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Sample records for aba receptor family

  1. The unique mode of action of a divergent member of the ABA-receptor protein family in ABA and stress signaling

    PubMed Central

    Zhao, Yang; Chan, Zhulong; Xing, Lu; Liu, Xiaodong; Hou, Yueh-Ju; Chinnusamy, Viswanathan; Wang, Pengcheng; Duan, Chengguo; Zhu, Jian-Kang

    2013-01-01

    Proteins in the PYR/PYL/RCAR family (PYLs) are known as receptors for the phytohormone ABA. Upon ABA binding, PYL adopts a conformation that allows it to interact with and inhibit clade A protein phosphatase 2Cs (PP2Cs), which are known as the co-receptors for ABA. Inhibition of the PP2Cs then leads to the activation of the SnRK2 family protein kinases that phosphorylate and activate downstream effectors in ABA response pathways. The PYL family has 14 members in Arabidopsis, 13 of which have been demonstrated to function as ABA receptors. The function of PYL13, a divergent member of the family, has been enigmatic. We report here that PYL13 differs from the other PYLs in three key residues that affect ABA perception, and mutations in these three residues can convert PYL13 into a partially functional ABA receptor. Transgenic plants overexpressing PYL13 show increased ABA sensitivity in seed germination and postgermination seedling establishment as well as decreased stomatal conductance, increased water-use efficiency, accelerated stress-responsive gene expression, and enhanced drought resistance. pyl13 mutant plants are less sensitive to ABA inhibition of postgermination seedling establishment. PYL13 interacts with and inhibits some members of clade A PP2Cs (PP2CA in particular) in an ABA-independent manner. PYL13 also interacts with the other PYLs and antagonizes their function as ABA receptors. Our results show that PYL13 is not an ABA receptor but can modulate the ABA pathway by interacting with and inhibiting both the PYL receptors and the PP2C co-receptors. PMID:24189045

  2. Identification and mechanism of ABA receptor antagonism

    SciTech Connect

    Melcher, Karsten; Xu, Yong; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Chinnusamy, Viswanathan; Suino-Powell, Kelly M; Kovach, Amanda; Tham, Fook S.; Cutler, Sean R.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H. Eric

    2010-11-11

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands.

  3. ABA Receptors: Past, Present and Future

    SciTech Connect

    Guo, Jianjun; Yang, Xiaohan; Weston, David; Chen, Jay

    2011-01-01

    Abscisic acid (ABA) is the key plant stress hormone. Consistent with the earlier studies in support of the presence of both membrane- and cytoplasm-localized ABA receptors, recent studies have identified multiple ABA receptors located in various subcellular locations. These include a chloroplast envelope-localized receptor (the H subunit of Chloroplast Mg2+-chelatase/ABA Receptor), two plasma membrane-localized receptors (G-protein Coupled Receptor 2 and GPCR-type G proteins), and one cytosol/nucleus-localized Pyrabactin Resistant (PYR)/PYR-Like (PYL)/Regulatory Component of ABA Receptor 1 (RCAR). Although the downstream molecular events for most of the identified ABA receptors are currently unknown, one of them, PYR/PYL/RACR was found to directly bind and regulate the activity of a long-known central regulator of ABA signaling, the A-group protein phosphatase 2C (PP2C). Together with the Sucrose Non-fermentation Kinase Subfamily 2 (SnRK2s) protein kinases, a central signaling complex (ABA-PYR-PP2Cs-SnRK2s) that is responsible for ABA signal perception and transduction is supported by abundant genetic, physiological, biochemical and structural evidence. The identification of multiple ABA receptors has advanced our understanding of ABA signal perception and transduction while adding an extra layer of complexity.

  4. Conformationally restricted 3'-modified ABA analogs for controlling ABA receptors.

    PubMed

    Takeuchi, Jun; Ohnishi, Toshiyuki; Okamoto, Masanori; Todoroki, Yasushi

    2015-04-14

    The physiological functions of abscisic acid (ABA) are regulated by a signal transduction pathway involving cytosolic ABA receptors, which include 14 PYR/PYL/RCAR (PYL) proteins in Arabidopsis. The development of a PYL antagonist could be a valuable tool to improve our understanding of the roles of ABA. We previously developed 3'-hexylsulfanyl-ABA (AS6), whose S-hexyl chain blocks protein phosphatase 2C (PP2C) binding by steric hindrance. This finding not only validated our structure-based approach to the design of a PYL antagonist, but also provided a basis for the development of a more potent or subclass/subtype selective PYL antagonist. In the present study, we synthesized a conformationally restricted analog of AS6, namely propenyl-ABA with an O-butyl chain (PAO4), to improve the affinity for PYL proteins by reducing the entropic penalty for binding to the receptors. In seed germination assays, (+)-PAO4 was a slightly stronger antagonist than AS6 in Arabidopsis and a significantly stronger antagonist in lettuce. Analysis of the thermodynamic parameters associated with the formation of the Arabidopsis PYL-(+)-PAO4 complex revealed that (+)-PAO4 binds more strongly to PYL5 than AS6 owing to an entropic advantage. In PP2C assays, this enhancement effect was observed only for the monomeric PYL subclass containing PYL5, suggesting that (+)-PAO4 is more effective than AS6 in physiological events involving monomeric PYL proteins as ABA receptors. PMID:25758810

  5. Rapid Phosphoproteomic Effects of Abscisic Acid (ABA) on Wild-Type and ABA Receptor-Deficient A. thaliana Mutants*

    PubMed Central

    Minkoff, Benjamin B.; Stecker, Kelly E.; Sussman, Michael R.

    2015-01-01

    Abscisic acid (ABA)1 is a plant hormone that controls many aspects of plant growth, including seed germination, stomatal aperture size, and cellular drought response. ABA interacts with a unique family of 14 receptor proteins. This interaction leads to the activation of a family of protein kinases, SnRK2s, which in turn phosphorylate substrates involved in many cellular processes. The family of receptors appears functionally redundant. To observe a measurable phenotype, four of the fourteen receptors have to be mutated to create a multilocus loss-of-function quadruple receptor (QR) mutant, which is much less sensitive to ABA than wild-type (WT) plants. Given these phenotypes, we asked whether or not a difference in ABA response between the WT and QR backgrounds would manifest on a phosphorylation level as well. We tested WT and QR mutant ABA response using isotope-assisted quantitative phosphoproteomics to determine what ABA-induced phosphorylation changes occur in WT plants within 5 min of ABA treatment and how that phosphorylation pattern is altered in the QR mutant. We found multiple ABA-induced phosphorylation changes that occur within 5 min of treatment, including three SnRK2 autophosphorylation events and phosphorylation on SnRK2 substrates. The majority of robust ABA-dependent phosphorylation changes observed were partially diminished in the QR mutant, whereas many smaller ABA-dependent phosphorylation changes observed in the WT were not responsive to ABA in the mutant. A single phosphorylation event was increased in response to ABA treatment in both the WT and QR mutant. A portion of the discovery data was validated using selected reaction monitoring-based targeted measurements on a triple quadrupole mass spectrometer. These data suggest that different subsets of phosphorylation events depend upon different subsets of the ABA receptor family to occur. Altogether, these data expand our understanding of the model by which the family of ABA receptors directs

  6. Rapid Phosphoproteomic Effects of Abscisic Acid (ABA) on Wild-Type and ABA Receptor-Deficient A. thaliana Mutants.

    PubMed

    Minkoff, Benjamin B; Stecker, Kelly E; Sussman, Michael R

    2015-05-01

    Abscisic acid (ABA)¹ is a plant hormone that controls many aspects of plant growth, including seed germination, stomatal aperture size, and cellular drought response. ABA interacts with a unique family of 14 receptor proteins. This interaction leads to the activation of a family of protein kinases, SnRK2s, which in turn phosphorylate substrates involved in many cellular processes. The family of receptors appears functionally redundant. To observe a measurable phenotype, four of the fourteen receptors have to be mutated to create a multilocus loss-of-function quadruple receptor (QR) mutant, which is much less sensitive to ABA than wild-type (WT) plants. Given these phenotypes, we asked whether or not a difference in ABA response between the WT and QR backgrounds would manifest on a phosphorylation level as well. We tested WT and QR mutant ABA response using isotope-assisted quantitative phosphoproteomics to determine what ABA-induced phosphorylation changes occur in WT plants within 5 min of ABA treatment and how that phosphorylation pattern is altered in the QR mutant. We found multiple ABA-induced phosphorylation changes that occur within 5 min of treatment, including three SnRK2 autophosphorylation events and phosphorylation on SnRK2 substrates. The majority of robust ABA-dependent phosphorylation changes observed were partially diminished in the QR mutant, whereas many smaller ABA-dependent phosphorylation changes observed in the WT were not responsive to ABA in the mutant. A single phosphorylation event was increased in response to ABA treatment in both the WT and QR mutant. A portion of the discovery data was validated using selected reaction monitoring-based targeted measurements on a triple quadrupole mass spectrometer. These data suggest that different subsets of phosphorylation events depend upon different subsets of the ABA receptor family to occur. Altogether, these data expand our understanding of the model by which the family of ABA receptors directs

  7. An ABA-increased interaction of the PYL6 ABA receptor with MYC2 Transcription Factor: A putative link of ABA and JA signaling

    PubMed Central

    Aleman, Fernando; Yazaki, Junshi; Lee, Melissa; Takahashi, Yohei; Kim, Alice Y.; Li, Zixing; Kinoshita, Toshinori; Ecker, Joseph R.; Schroeder, Julian I.

    2016-01-01

    Abscisic acid (ABA) is a plant hormone that mediates abiotic stress tolerance and regulates growth and development. ABA binds to members of the PYL/RCAR ABA receptor family that initiate signal transduction inhibiting type 2C protein phosphatases. Although crosstalk between ABA and the hormone Jasmonic Acid (JA) has been shown, the molecular entities that mediate this interaction have yet to be fully elucidated. We report a link between ABA and JA signaling through a direct interaction of the ABA receptor PYL6 (RCAR9) with the basic helix-loop-helix transcription factor MYC2. PYL6 and MYC2 interact in yeast two hybrid assays and the interaction is enhanced in the presence of ABA. PYL6 and MYC2 interact in planta based on bimolecular fluorescence complementation and co-immunoprecipitation of the proteins. Furthermore, PYL6 was able to modify transcription driven by MYC2 using JAZ6 and JAZ8 DNA promoter elements in yeast one hybrid assays. Finally, pyl6 T-DNA mutant plants show an increased sensitivity to the addition of JA along with ABA in cotyledon expansion experiments. Overall, the present study identifies a direct mechanism for transcriptional modulation mediated by an ABA receptor different from the core ABA signaling pathway, and a putative mechanistic link connecting ABA and JA signaling pathways. PMID:27357749

  8. Structural basis for selective activation of ABA receptors

    SciTech Connect

    Peterson, Francis C.; Burgie, E. Sethe; Park, Sang-Youl; Jensen, Davin R.; Weiner, Joshua J.; Bingman, Craig A.; Chang, Chia-En A.; Cutler, Sean R.; Phillips, Jr., George N.; Volkman, Brian F.

    2010-11-01

    Changing environmental conditions and lessening fresh water supplies have sparked intense interest in understanding and manipulating abscisic acid (ABA) signaling, which controls adaptive responses to drought and other abiotic stressors. We recently discovered a selective ABA agonist, pyrabactin, and used it to discover its primary target PYR1, the founding member of the PYR/PYL family of soluble ABA receptors. To understand pyrabactin's selectivity, we have taken a combined structural, chemical and genetic approach. We show that subtle differences between receptor binding pockets control ligand orientation between productive and nonproductive modes. Nonproductive binding occurs without gate closure and prevents receptor activation. Observations in solution show that these orientations are in rapid equilibrium that can be shifted by mutations to control maximal agonist activity. Our results provide a robust framework for the design of new agonists and reveal a new mechanism for agonist selectivity.

  9. ABA receptor PYL9 promotes drought resistance and leaf senescence.

    PubMed

    Zhao, Yang; Chan, Zhulong; Gao, Jinghui; Xing, Lu; Cao, Minjie; Yu, Chunmei; Hu, Yuanlei; You, Jun; Shi, Haitao; Zhu, Yingfang; Gong, Yuehua; Mu, Zixin; Wang, Haiqing; Deng, Xin; Wang, Pengcheng; Bressan, Ray A; Zhu, Jian-Kang

    2016-02-16

    Drought stress is an important environmental factor limiting plant productivity. In this study, we screened drought-resistant transgenic plants from 65 promoter-pyrabactin resistance 1-like (PYL) abscisic acid (ABA) receptor gene combinations and discovered that pRD29A::PYL9 transgenic lines showed dramatically increased drought resistance and drought-induced leaf senescence in both Arabidopsis and rice. Previous studies suggested that ABA promotes senescence by causing ethylene production. However, we found that ABA promotes leaf senescence in an ethylene-independent manner by activating sucrose nonfermenting 1-related protein kinase 2s (SnRK2s), which subsequently phosphorylate ABA-responsive element-binding factors (ABFs) and Related to ABA-Insensitive 3/VP1 (RAV1) transcription factors. The phosphorylated ABFs and RAV1 up-regulate the expression of senescence-associated genes, partly by up-regulating the expression of Oresara 1. The pyl9 and ABA-insensitive 1-1 single mutants, pyl8-1pyl9 double mutant, and snrk2.2/3/6 triple mutant showed reduced ABA-induced leaf senescence relative to the WT, whereas pRD29A::PYL9 transgenic plants showed enhanced ABA-induced leaf senescence. We found that leaf senescence may benefit drought resistance by helping to generate an osmotic potential gradient, which is increased in pRD29A::PYL9 transgenic plants and causes water to preferentially flow to developing tissues. Our results uncover the molecular mechanism of ABA-induced leaf senescence and suggest an important role of PYL9 and leaf senescence in promoting resistance to extreme drought stress. PMID:26831097

  10. ABA receptor PYL9 promotes drought resistance and leaf senescence

    PubMed Central

    Zhao, Yang; Chan, Zhulong; Gao, Jinghui; Xing, Lu; Cao, Minjie; Yu, Chunmei; Hu, Yuanlei; You, Jun; Shi, Haitao; Zhu, Yingfang; Gong, Yuehua; Mu, Zixin; Wang, Haiqing; Deng, Xin; Wang, Pengcheng; Bressan, Ray A.; Zhu, Jian-Kang

    2016-01-01

    Drought stress is an important environmental factor limiting plant productivity. In this study, we screened drought-resistant transgenic plants from 65 promoter-pyrabactin resistance 1-like (PYL) abscisic acid (ABA) receptor gene combinations and discovered that pRD29A::PYL9 transgenic lines showed dramatically increased drought resistance and drought-induced leaf senescence in both Arabidopsis and rice. Previous studies suggested that ABA promotes senescence by causing ethylene production. However, we found that ABA promotes leaf senescence in an ethylene-independent manner by activating sucrose nonfermenting 1-related protein kinase 2s (SnRK2s), which subsequently phosphorylate ABA-responsive element-binding factors (ABFs) and Related to ABA-Insensitive 3/VP1 (RAV1) transcription factors. The phosphorylated ABFs and RAV1 up-regulate the expression of senescence-associated genes, partly by up-regulating the expression of Oresara 1. The pyl9 and ABA-insensitive 1-1 single mutants, pyl8-1pyl9 double mutant, and snrk2.2/3/6 triple mutant showed reduced ABA-induced leaf senescence relative to the WT, whereas pRD29A::PYL9 transgenic plants showed enhanced ABA-induced leaf senescence. We found that leaf senescence may benefit drought resistance by helping to generate an osmotic potential gradient, which is increased in pRD29A::PYL9 transgenic plants and causes water to preferentially flow to developing tissues. Our results uncover the molecular mechanism of ABA-induced leaf senescence and suggest an important role of PYL9 and leaf senescence in promoting resistance to extreme drought stress. PMID:26831097

  11. ABA receptor PYL9 promotes drought resistance and leaf senescence.

    PubMed

    Zhao, Yang; Chan, Zhulong; Gao, Jinghui; Xing, Lu; Cao, Minjie; Yu, Chunmei; Hu, Yuanlei; You, Jun; Shi, Haitao; Zhu, Yingfang; Gong, Yuehua; Mu, Zixin; Wang, Haiqing; Deng, Xin; Wang, Pengcheng; Bressan, Ray A; Zhu, Jian-Kang

    2016-02-16

    Drought stress is an important environmental factor limiting plant productivity. In this study, we screened drought-resistant transgenic plants from 65 promoter-pyrabactin resistance 1-like (PYL) abscisic acid (ABA) receptor gene combinations and discovered that pRD29A::PYL9 transgenic lines showed dramatically increased drought resistance and drought-induced leaf senescence in both Arabidopsis and rice. Previous studies suggested that ABA promotes senescence by causing ethylene production. However, we found that ABA promotes leaf senescence in an ethylene-independent manner by activating sucrose nonfermenting 1-related protein kinase 2s (SnRK2s), which subsequently phosphorylate ABA-responsive element-binding factors (ABFs) and Related to ABA-Insensitive 3/VP1 (RAV1) transcription factors. The phosphorylated ABFs and RAV1 up-regulate the expression of senescence-associated genes, partly by up-regulating the expression of Oresara 1. The pyl9 and ABA-insensitive 1-1 single mutants, pyl8-1pyl9 double mutant, and snrk2.2/3/6 triple mutant showed reduced ABA-induced leaf senescence relative to the WT, whereas pRD29A::PYL9 transgenic plants showed enhanced ABA-induced leaf senescence. We found that leaf senescence may benefit drought resistance by helping to generate an osmotic potential gradient, which is increased in pRD29A::PYL9 transgenic plants and causes water to preferentially flow to developing tissues. Our results uncover the molecular mechanism of ABA-induced leaf senescence and suggest an important role of PYL9 and leaf senescence in promoting resistance to extreme drought stress.

  12. The ABA receptor PYL9 together with PYL8 plays an important role in regulating lateral root growth.

    PubMed

    Xing, Lu; Zhao, Yang; Gao, Jinghui; Xiang, Chengbin; Zhu, Jian-Kang

    2016-01-01

    Abscisic acid is a phytohormone regulating plant growth, development and stress responses. PYR1/PYL/RCAR proteins are ABA receptors that function by inhibiting PP2Cs to activate SnRK2s, resulting in phosphorylation of ABFs and other effectors of ABA response pathways. Exogenous ABA induces growth quiescence of lateral roots, which is prolonged by knockout of the ABA receptor PYL8. Among the 14 members of PYR1/PYL/RCAR protein family, PYL9 is a close relative of PYL8. Here we show that knockout of both PYL9 and PYL8 resulted in a longer ABA-induced quiescence on lateral root growth and a reduced sensitivity to ABA on primary root growth and lateral root formation compared to knockout of PYL8 alone. Induced overexpression of PYL9 promoted the lateral root elongation in the presence of ABA. The prolonged quiescent phase of the pyl8-1pyl9 double mutant was reversed by exogenous IAA. PYL9 may regulate auxin-responsive genes in vivo through direct interaction with MYB77 and MYB44. Thus, PYL9 and PYL8 are both responsible for recovery of lateral root from ABA inhibition via MYB transcription factors. PMID:27256015

  13. The ABA receptor PYL9 together with PYL8 plays an important role in regulating lateral root growth

    PubMed Central

    Xing, Lu; Zhao, Yang; Gao, Jinghui; Xiang, Chengbin; Zhu, Jian-Kang

    2016-01-01

    Abscisic acid is a phytohormone regulating plant growth, development and stress responses. PYR1/PYL/RCAR proteins are ABA receptors that function by inhibiting PP2Cs to activate SnRK2s, resulting in phosphorylation of ABFs and other effectors of ABA response pathways. Exogenous ABA induces growth quiescence of lateral roots, which is prolonged by knockout of the ABA receptor PYL8. Among the 14 members of PYR1/PYL/RCAR protein family, PYL9 is a close relative of PYL8. Here we show that knockout of both PYL9 and PYL8 resulted in a longer ABA-induced quiescence on lateral root growth and a reduced sensitivity to ABA on primary root growth and lateral root formation compared to knockout of PYL8 alone. Induced overexpression of PYL9 promoted the lateral root elongation in the presence of ABA. The prolonged quiescent phase of the pyl8-1pyl9 double mutant was reversed by exogenous IAA. PYL9 may regulate auxin-responsive genes in vivo through direct interaction with MYB77 and MYB44. Thus, PYL9 and PYL8 are both responsible for recovery of lateral root from ABA inhibition via MYB transcription factors. PMID:27256015

  14. Mg-chelatase H subunit affects ABA signaling in stomatal guard cells, but is not an ABA receptor in Arabidopsis thaliana.

    PubMed

    Tsuzuki, Tomo; Takahashi, Koji; Inoue, Shin-ichiro; Okigaki, Yukiko; Tomiyama, Masakazu; Hossain, Mohammad Anowar; Shimazaki, Ken-ichiro; Murata, Yoshiyuki; Kinoshita, Toshinori

    2011-07-01

    Mg-chelatase H subunit (CHLH) is a multifunctional protein involved in chlorophyll synthesis, plastid-to-nucleus retrograde signaling, and ABA perception. However, whether CHLH acts as an actual ABA receptor remains controversial. Here we present evidence that CHLH affects ABA signaling in stomatal guard cells but is not itself an ABA receptor. We screened ethyl methanesulfonate-treated Arabidopsis thaliana plants with a focus on stomatal aperture-dependent water loss in detached leaves and isolated a rapid transpiration in detached leaves 1 (rtl1) mutant that we identified as a novel missense mutant of CHLH. The rtl1 and CHLH RNAi plants showed phenotypes in which stomatal movements were insensitive to ABA, while the rtl1 phenotype showed normal sensitivity to ABA with respect to seed germination and root growth. ABA-binding analyses using (3)H-labeled ABA revealed that recombinant CHLH did not bind ABA, but recombinant pyrabactin resistance 1, a reliable ABA receptor used as a control, showed specific binding. Moreover, we found that the rtl1 mutant showed ABA-induced stomatal closure when a high concentration of extracellular Ca(2+) was present and that a knockout mutant of Mg-chelatase I subunit (chli1) showed the same ABA-insensitive phenotype as rtl1. These results suggest that the Mg-chelatase complex as a whole affects the ABA-signaling pathway for stomatal movements.

  15. Overexpression of the Artemisia Orthologue of ABA Receptor, AaPYL9, Enhances ABA Sensitivity and Improves Artemisinin Content in Artemisia annua L

    PubMed Central

    Zhang, Fangyuan; Lu, Xu; Lv, Zongyou; Zhang, Ling; Zhu, Mengmeng; Jiang, Weiming; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2013-01-01

    The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. In this study, we cloned an ABA receptor orthologue, AaPYL9, from Artemisia annua L. AaPYL9 is expressed highly in leaf and flower. AaPYL9 protein can be localized in both nucleus and cytoplasm. Yeast two-hybrid assay shows AaPYL9 can specifically interact with AtABI1 but not with AtABI2, AtHAB1 or AtHAB2. ABA can enhance the interaction between AaPYL9 and AtABI1 while AaPYL9-89 Pro→Ser and AaPYL9-116 His→Ala point mutations abolishes the interaction. BiFC assay shows that AaPYL9 interacts with AtABI1 in nucleus in planta. Transgenic Arabidopsis plants over-expressing AaPYL9 are more sensitive to ABA in the seed germination and primary root growth than wild type. Consistent with this, ABA report genes have higher expression in AaPYL9 overexpressing plants compared to wild type after ABA treatment. Moreover, overexpression of AaPYL9 in A. annua increases not only drought tolerance, but also artemisinin content after ABA treatment, with significant enhancement of the expression of key genes in artemisinin biosynthesis. This study provides a way to develop A. annua with high-yielding artemisinin and high drought resistance. PMID:23437216

  16. Degradation of the ABA co-receptor ABI1 by PUB12/13 U-box E3 ligases

    PubMed Central

    Kong, Lingyao; Cheng, Jinkui; Zhu, Yujuan; Ding, Yanglin; Meng, Jingjing; Chen, Zhizhong; Xie, Qi; Guo, Yan; Li, Jigang; Yang, Shuhua; Gong, Zhizhong

    2015-01-01

    Clade A protein phosphatase 2Cs (PP2Cs) are abscisic acid (ABA) co-receptors that block ABA signalling by inhibiting the downstream protein kinases. ABA signalling is activated after PP2Cs are inhibited by ABA-bound PYR/PYL/RCAR ABA receptors (PYLs) in Arabidopsis. However, whether these PP2Cs are regulated by other factors remains unknown. Here, we report that ABI1 (ABA-INSENSITIVE 1) can interact with the U-box E3 ligases PUB12 and PUB13, but is ubiquitinated only when it interacts with ABA receptors in an in vitro assay. A mutant form of ABI1-1 that is unable to interact with PYLs is more stable than the wild-type protein. Both ABI1 degradation and all tested ABA responses are reduced in pub12 pub13 mutants compared with the wild type. Introducing the abi1-3 loss-of-function mutation into pub12 pub13 mutant recovers the ABA-insensitive phenotypes of the pub12 pub13 mutant. We thus uncover an important regulatory mechanism for regulating ABI1 levels by PUB12 and PUB13. PMID:26482222

  17. An ABA-mimicking ligand that reduces water loss and promotes drought resistance in plants

    PubMed Central

    Cao, Minjie; Liu, Xue; Zhang, Yan; Xue, Xiaoqian; Zhou, X Edward; Melcher, Karsten; Gao, Pan; Wang, Fuxing; Zeng, Liang; Zhao, Yang; Zhao, Yang; Deng, Pan; Zhong, Dafang; Zhu, Jian-Kang; Xu, H Eric; Xu, Yong

    2013-01-01

    Abscisic acid (ABA) is the most important hormone for plants to resist drought and other abiotic stresses. ABA binds directly to the PYR/PYL family of ABA receptors, resulting in inhibition of type 2C phosphatases (PP2C) and activation of downstream ABA signaling. It is envisioned that intervention of ABA signaling by small molecules could help plants to overcome abiotic stresses such as drought, cold and soil salinity. However, chemical instability and rapid catabolism by plant enzymes limit the practical application of ABA itself. Here we report the identification of a small molecule ABA mimic (AM1) that acts as a potent activator of multiple members of the family of ABA receptors. In Arabidopsis, AM1 activates a gene network that is highly similar to that induced by ABA. Treatments with AM1 inhibit seed germination, prevent leaf water loss, and promote drought resistance. We solved the crystal structure of AM1 in complex with the PYL2 ABA receptor and the HAB1 PP2C, which revealed that AM1 mediates a gate-latch-lock interacting network, a structural feature that is conserved in the ABA-bound receptor/PP2C complex. Together, these results demonstrate that a single small molecule ABA mimic can activate multiple ABA receptors and protect plants from water loss and drought stress. Moreover, the AM1 complex crystal structure provides a structural basis for designing the next generation of ABA-mimicking small molecules. PMID:23835477

  18. A 14-3-3 Family Protein from Wild Soybean (Glycine Soja) Regulates ABA Sensitivity in Arabidopsis

    PubMed Central

    Sun, Xiaoli; Sun, Mingzhe; Jia, Bowei; Chen, Chao; Qin, Zhiwei; Yang, Kejun; Shen, Yang; Meiping, Zhang; Mingyang, Cong; Zhu, Yanming

    2015-01-01

    It is widely accepted that the 14-3-3 family proteins are key regulators of multiple stress signal transduction cascades. By conducting genome-wide analysis, researchers have identified the soybean 14-3-3 family proteins; however, until now, there is still no direct genetic evidence showing the involvement of soybean 14-3-3s in ABA responses. Hence, in this study, based on the latest Glycine max genome on Phytozome v10.3, we initially analyzed the evolutionary relationship, genome organization, gene structure and duplication, and three-dimensional structure of soybean 14-3-3 family proteins systematically. Our results suggested that soybean 14-3-3 family was highly evolutionary conserved and possessed segmental duplication in evolution. Then, based on our previous functional characterization of a Glycine soja 14-3-3 protein GsGF14o in drought stress responses, we further investigated the expression characteristics of GsGF14o in detail, and demonstrated its positive roles in ABA sensitivity. Quantitative real-time PCR analyses in Glycine soja seedlings and GUS activity assays in PGsGF14O:GUS transgenic Arabidopsis showed that GsGF14o expression was moderately and rapidly induced by ABA treatment. As expected, GsGF14o overexpression in Arabidopsis augmented the ABA inhibition of seed germination and seedling growth, promoted the ABA induced stomata closure, and up-regulated the expression levels of ABA induced genes. Moreover, through yeast two hybrid analyses, we further demonstrated that GsGF14o physically interacted with the AREB/ABF transcription factors in yeast cells. Taken together, results presented in this study strongly suggested that GsGF14o played an important role in regulation of ABA sensitivity in Arabidopsis. PMID:26717241

  19. A 14-3-3 Family Protein from Wild Soybean (Glycine Soja) Regulates ABA Sensitivity in Arabidopsis.

    PubMed

    Sun, Xiaoli; Sun, Mingzhe; Jia, Bowei; Chen, Chao; Qin, Zhiwei; Yang, Kejun; Shen, Yang; Meiping, Zhang; Mingyang, Cong; Zhu, Yanming

    2015-01-01

    It is widely accepted that the 14-3-3 family proteins are key regulators of multiple stress signal transduction cascades. By conducting genome-wide analysis, researchers have identified the soybean 14-3-3 family proteins; however, until now, there is still no direct genetic evidence showing the involvement of soybean 14-3-3s in ABA responses. Hence, in this study, based on the latest Glycine max genome on Phytozome v10.3, we initially analyzed the evolutionary relationship, genome organization, gene structure and duplication, and three-dimensional structure of soybean 14-3-3 family proteins systematically. Our results suggested that soybean 14-3-3 family was highly evolutionary conserved and possessed segmental duplication in evolution. Then, based on our previous functional characterization of a Glycine soja 14-3-3 protein GsGF14o in drought stress responses, we further investigated the expression characteristics of GsGF14o in detail, and demonstrated its positive roles in ABA sensitivity. Quantitative real-time PCR analyses in Glycine soja seedlings and GUS activity assays in PGsGF14O:GUS transgenic Arabidopsis showed that GsGF14o expression was moderately and rapidly induced by ABA treatment. As expected, GsGF14o overexpression in Arabidopsis augmented the ABA inhibition of seed germination and seedling growth, promoted the ABA induced stomata closure, and up-regulated the expression levels of ABA induced genes. Moreover, through yeast two hybrid analyses, we further demonstrated that GsGF14o physically interacted with the AREB/ABF transcription factors in yeast cells. Taken together, results presented in this study strongly suggested that GsGF14o played an important role in regulation of ABA sensitivity in Arabidopsis. PMID:26717241

  20. A 14-3-3 Family Protein from Wild Soybean (Glycine Soja) Regulates ABA Sensitivity in Arabidopsis.

    PubMed

    Sun, Xiaoli; Sun, Mingzhe; Jia, Bowei; Chen, Chao; Qin, Zhiwei; Yang, Kejun; Shen, Yang; Meiping, Zhang; Mingyang, Cong; Zhu, Yanming

    2015-01-01

    It is widely accepted that the 14-3-3 family proteins are key regulators of multiple stress signal transduction cascades. By conducting genome-wide analysis, researchers have identified the soybean 14-3-3 family proteins; however, until now, there is still no direct genetic evidence showing the involvement of soybean 14-3-3s in ABA responses. Hence, in this study, based on the latest Glycine max genome on Phytozome v10.3, we initially analyzed the evolutionary relationship, genome organization, gene structure and duplication, and three-dimensional structure of soybean 14-3-3 family proteins systematically. Our results suggested that soybean 14-3-3 family was highly evolutionary conserved and possessed segmental duplication in evolution. Then, based on our previous functional characterization of a Glycine soja 14-3-3 protein GsGF14o in drought stress responses, we further investigated the expression characteristics of GsGF14o in detail, and demonstrated its positive roles in ABA sensitivity. Quantitative real-time PCR analyses in Glycine soja seedlings and GUS activity assays in PGsGF14O:GUS transgenic Arabidopsis showed that GsGF14o expression was moderately and rapidly induced by ABA treatment. As expected, GsGF14o overexpression in Arabidopsis augmented the ABA inhibition of seed germination and seedling growth, promoted the ABA induced stomata closure, and up-regulated the expression levels of ABA induced genes. Moreover, through yeast two hybrid analyses, we further demonstrated that GsGF14o physically interacted with the AREB/ABF transcription factors in yeast cells. Taken together, results presented in this study strongly suggested that GsGF14o played an important role in regulation of ABA sensitivity in Arabidopsis.

  1. The Arabidopsis F-box E3 ligase RIFP1 plays a negative role in abscisic acid signalling by facilitating ABA receptor RCAR3 degradation.

    PubMed

    Li, Ying; Zhang, Liang; Li, Dekuan; Liu, Zhibin; Wang, Jianmei; Li, Xufeng; Yang, Yi

    2016-03-01

    The phytohormone abscisic acid (ABA) plays a vital role in plant growth and development. The function of ABA is mediated by a group of newly discovered ABA receptors, named PYRABACTIN RESISTANCE 1/PYR-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORs (PYR1/PYLs/RCARs). Here, we report that an Arabidopsis thaliana F-box protein RCAR3 INTERACTING F-BOX PROTEIN 1 (RIFP1) interacts with ABA receptor (RCAR3) and SCF E3 ligase complex subunits Arabidopsis SKP1-LIKE PROTEINs (ASKs) in vitro and in vivo. The rifp1 mutant plants displayed increased ABA-mediated inhibition of seed germination and water loss of detached leaves, while the overexpression of RIFP1 in Arabidopsis led to plants being insensitive to ABA. Meanwhile, the rifp1 mutant plants showed greater tolerance to water deficit. In addition, the RCAR3 protein level was more stable in the rifp1 mutant plants than in the wild-type plants, indicating that RIFP1 facilitates the proteasome degradation of RCAR3. Accordingly, the loss of RIFP1 increased the transcript levels of several ABA-responsive genes. Taken together, these data indicate that RIFP1 plays a negative role in the RCAR3-mediated ABA signalling pathway and likely functions as an adaptor subunit of the SCF ubiquitin ligase complex to regulate ABA receptor RCAR3 stability. PMID:26386272

  2. Nitric oxide modulates sensitivity to ABA.

    PubMed

    Lozano-Juste, Jorge; León, José

    2010-03-01

    Nitric oxide (NO) is a gas with crucial signaling functions in plant defense and development. As demonstrated by generating a triple nia1nia2noa1-2 mutant with extremely low levels of NO (February 2010 issue of Plant Physiology), NO is synthesized in plants through mainly two different pathways involving nitrate reductase (NR/NIA) and NO Associated 1 (AtNOA1) proteins. Depletion of basal NO levels leads to a priming of ABA-triggered responses that causes hypersensitivity to this hormone and results in enhanced seed dormancy and decreased seed germination and seedling establishment in the triple mutant. NO produced under non-stressed conditions represses inhibition of seed developmental transitions by ABA. Moreover, NO plays a positive role in post-germinative vegetative development and also exerts a critical control of ABA-related functions on stomata closure. The triple nia1nia2noa1-2 mutant is hypersensitive to ABA in stomatal closure thus resulting in a extreme phenotype of resistance to drought. In the light of the recent discovery of PYR/PYL/RCAR as a family of potential ABA receptors, regulation of ABA sensitivity by NO may be exerted either directly on ABA receptors or on downstream signaling components; both two aspects that deserve our present and future attention.

  3. From the Classroom to the Family Room: Using ABA for Best Behavior

    ERIC Educational Resources Information Center

    Smith, Dawn

    2010-01-01

    When it comes to supporting individuals with disabilities including Autism Spectrum Disorder (ASD), Applied Behavior Analysis (ABA) can be an invaluable tool in understanding and changing behavior. More than a technique or method, ABA is a disciplined approach rooted in science to teach specific skills and then reinforce them so individuals can…

  4. The somatostatin receptor family.

    PubMed

    Patel, Y C; Greenwood, M T; Panetta, R; Demchyshyn, L; Niznik, H; Srikant, C B

    1995-01-01

    The diverse biological effects of somatostatin (SST) are mediated through a family of G protein coupled receptors of which 5 members have been recently identified by molecular cloning. This review focuses on the molecular biology, pharmacology, expression, and function of these receptors with particular emphasis on the human (h) homologs. hSSTRs are encoded by a family of 5 genes which map to separate chromosomes and which, with one exception, are intronless. SSTR2 gives rise to spliced variants, SSTR2A and 2B. hSSTR1-4 display weak selectivity for SST-14 binding whereas hSSTR5 is SST-28 selective. Based on structural similarity and reactivity for octapeptide and hexapeptide SST analogs, hSSTR2,3, and 5 belong to a similar SSTR subclass. hSSTR1 and 4 react poorly with these analogs and belong to a separate subclass. All 5 hSSTRs are functionally coupled to inhibition of adenylyl cyclase via pertussis toxin sensitive GTP binding proteins. Some of the subtypes are also coupled to tyrosine phosphatase (SSTR1,2), Ca2+ channels (SSTR2), Na+/H+ exchanger (SSTR1), PLA-2 (SSTR4), and MAP kinase (SSTR4). mRNA for SSTR1-5 is widely expressed in brain and peripheral organs and displays an overlapping but characteristic pattern that is subtype-selective, and tissue- and species-specific. Pituitary and islet tumors express several SSTR genes suggesting that multiple SSTR subtypes are coexpressed in the same cell. Structure-function studies indicate that the core residues in SST-14 ligand Phe6-Phe11 dock within a ligand binding pocket located in TMDs 3-7 which is lined by hydrophobic and charged amino acid residues.

  5. Function of ABA in Stomatal Defense against Biotic and Drought Stresses.

    PubMed

    Lim, Chae Woo; Baek, Woonhee; Jung, Jangho; Kim, Jung-Hyun; Lee, Sung Chul

    2015-01-01

    The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses--especially ABA receptors--have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases. PMID:26154766

  6. Function of ABA in Stomatal Defense against Biotic and Drought Stresses

    PubMed Central

    Lim, Chae Woo; Baek, Woonhee; Jung, Jangho; Kim, Jung-Hyun; Lee, Sung Chul

    2015-01-01

    The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses—especially ABA receptors—have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases. PMID:26154766

  7. ABA homeostasis and signaling involving multiple subcellular compartments and multiple receptors.

    PubMed

    Xu, Zheng-Yi; Kim, Dae Heon; Hwang, Inhwan

    2013-06-01

    The plant hormone abscisic acid (ABA) plays pivotal roles in many important physiological processes including stomatal closure, seed dormancy, growth and various environmental stresses. In these responses, ABA action is under the control of complex regulatory mechanisms involving homeostasis, perception and signaling. Recent studies provide new insights into these processes, which are of great importance in understanding the mechanisms underlying the evolutionary principle of how plants can survive as a sessile organism under ever-changing environmental conditions. They also form the basis for designing plants that have an enhanced resistance to various stresses in particular abiotic stress.

  8. Elevated CO2-Induced Responses in Stomata Require ABA and ABA Signaling.

    PubMed

    Chater, Caspar; Peng, Kai; Movahedi, Mahsa; Dunn, Jessica A; Walker, Heather J; Liang, Yun-Kuan; McLachlan, Deirdre H; Casson, Stuart; Isner, Jean Charles; Wilson, Ian; Neill, Steven J; Hedrich, Rainer; Gray, Julie E; Hetherington, Alistair M

    2015-10-19

    An integral part of global environment change is an increase in the atmospheric concentration of CO2 ([CO2]) [1]. Increased [CO2] reduces leaf stomatal apertures and density of stomata that plays out as reductions in evapotranspiration [2-4]. Surprisingly, given the importance of transpiration to the control of terrestrial water fluxes [5] and plant nutrient acquisition [6], we know comparatively little about the molecular components involved in the intracellular signaling pathways by which [CO2] controls stomatal development and function [7]. Here, we report that elevated [CO2]-induced closure and reductions in stomatal density require the generation of reactive oxygen species (ROS), thereby adding a new common element to these signaling pathways. We also show that the PYR/RCAR family of ABA receptors [8, 9] and ABA itself are required in both responses. Using genetic approaches, we show that ABA in guard cells or their precursors is sufficient to mediate the [CO2]-induced stomatal density response. Taken together, our results suggest that stomatal responses to increased [CO2] operate through the intermediacy of ABA. In the case of [CO2]-induced reductions in stomatal aperture, this occurs by accessing the guard cell ABA signaling pathway. In both [CO2]-mediated responses, our data are consistent with a mechanism in which ABA increases the sensitivity of the system to [CO2] but could also be explained by requirement for a CO2-induced increase in ABA biosynthesis specifically in the guard cell lineage. Furthermore, the dependency of stomatal [CO2] signaling on ABA suggests that the ABA pathway is, in evolutionary terms, likely to be ancestral.

  9. Elevated CO2-Induced Responses in Stomata Require ABA and ABA Signaling.

    PubMed

    Chater, Caspar; Peng, Kai; Movahedi, Mahsa; Dunn, Jessica A; Walker, Heather J; Liang, Yun-Kuan; McLachlan, Deirdre H; Casson, Stuart; Isner, Jean Charles; Wilson, Ian; Neill, Steven J; Hedrich, Rainer; Gray, Julie E; Hetherington, Alistair M

    2015-10-19

    An integral part of global environment change is an increase in the atmospheric concentration of CO2 ([CO2]) [1]. Increased [CO2] reduces leaf stomatal apertures and density of stomata that plays out as reductions in evapotranspiration [2-4]. Surprisingly, given the importance of transpiration to the control of terrestrial water fluxes [5] and plant nutrient acquisition [6], we know comparatively little about the molecular components involved in the intracellular signaling pathways by which [CO2] controls stomatal development and function [7]. Here, we report that elevated [CO2]-induced closure and reductions in stomatal density require the generation of reactive oxygen species (ROS), thereby adding a new common element to these signaling pathways. We also show that the PYR/RCAR family of ABA receptors [8, 9] and ABA itself are required in both responses. Using genetic approaches, we show that ABA in guard cells or their precursors is sufficient to mediate the [CO2]-induced stomatal density response. Taken together, our results suggest that stomatal responses to increased [CO2] operate through the intermediacy of ABA. In the case of [CO2]-induced reductions in stomatal aperture, this occurs by accessing the guard cell ABA signaling pathway. In both [CO2]-mediated responses, our data are consistent with a mechanism in which ABA increases the sensitivity of the system to [CO2] but could also be explained by requirement for a CO2-induced increase in ABA biosynthesis specifically in the guard cell lineage. Furthermore, the dependency of stomatal [CO2] signaling on ABA suggests that the ABA pathway is, in evolutionary terms, likely to be ancestral. PMID:26455301

  10. Involvement of RD20, a member of caleosin family, in ABA-mediated regulation of germination in Arabidopsis thaliana.

    PubMed

    Aubert, Yann; Leba, Louis-Jérome; Cheval, Cécilia; Ranty, Benoit; Vavasseur, Alain; Aldon, Didier; Galaud, Jean-Philippe

    2011-04-01

    The RD20 gene encodes a member of the caleosin family, which is primarily known to function in the mobilization of seed storage lipids during germination. In contrast to other caleosins, RD20 expression is early-induced by water deficit conditions and we recently provided genetic evidence for its positive role in drought tolerance in Arabidopsis. RD20 is also responsive to pathogen infection and is constitutively expressed in diverse tissues and organs during development suggesting additional roles for this caleosin. This addendum describes further exploration of phenotypic alterations in T-DNA insertional rd20 mutant and knock-out complemented transgenic plants in the context of early development and susceptibility to a phytopathogenic bacteria. We show that the RD20 gene is involved in ABA-mediated inhibition of germination and does not play a significant role in plant defense against Pseudomonas syringae. PMID:21673513

  11. Involvement of RD20, a member of caleosin family, in ABA-mediated regulation of germination in Arabidopsis thaliana

    PubMed Central

    Cheval, Cécilia; Ranty, Benoit; Vavasseur, Alain; Aldon, Didier

    2011-01-01

    The RD20 gene encodes a member of the caleosin family, which is primarily known to function in the mobilization of seed storage lipids during germination. In contrast to other caleosins, RD20 expression is early-induced by water deficit conditions and we recently provided genetic evidence for its positive role in drought tolerance in Arabidopsis. RD20 is also responsive to pathogen infection and is constitutively expressed in diverse tissues and organs during development suggesting additional roles for this caleosin. This addendum describes further exploration of phenotypic alterations in T-DNA insertional rd20 mutant and knock-out complemented transgenic plants in the context of early development and susceptibility to a phytopathogenic bacteria. We show that the RD20 gene is involved in ABA-mediated inhibition of germination and does not play a significant role in plant defense against Pseudomonas syringae. PMID:21673513

  12. GEM, a member of the GRAM domain family of proteins, is part of the ABA signaling pathway

    PubMed Central

    Mauri, Nuria; Fernández-Marcos, María; Costas, Celina; Desvoyes, Bénédicte; Pichel, Antonio; Caro, Elena; Gutierrez, Crisanto

    2016-01-01

    Abscisic acid (ABA) is fundamental for plant development. Multiple factors have been identified that participate in the ABA signaling network, although a role of many proteins still await to be demonstrated. Here we have investigated the role of GEM (GL2 EXPRESSION MODULATOR), originally annotated as an ABA-responsive protein. GEM contains a GRAM domain, a feature shared with other eight Arabidopsis proteins for which we propose the name of GRE (GEM-RELATED) proteins. We found that (i) GEM expression responds to ABA, (ii) its promoter contains ABRE sites required for ABA response, and (iii) GEM expression depends on members of the ABA signaling pathway. This is consistent with the expression pattern of GEM during development in plant locations were ABA is known to play a direct role. We also found that GEM binds various phospholipids, e.g. mono and diphosphates and phosphatidic acid, suggesting a potential link of GEM with membrane-associated processes. Consistent with this, we found that the phosphoinositol-4-phosphate kinase PIP5K9 binds GEM in vivo. Finally, we demonstrated a role of GEM in seed dormancy. Together, our data led us to propose that GEM is an ABA-responsive protein that may function downstream of ABI5 as part of the ABA signaling pathway. PMID:26939893

  13. BRI1-Associated Receptor Kinase 1 Regulates Guard Cell ABA Signaling Mediated by Open Stomata 1 in Arabidopsis.

    PubMed

    Shang, Yun; Dai, Changbo; Lee, Myeong Min; Kwak, June M; Nam, Kyoung Hee

    2016-03-01

    Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid (ABA) plays key roles in regulating stomatal closure under various abiotic stresses. In this study, we revealed a novel role of BAK1 in guard cell ABA signaling. We found that the brassinosteroid (BR) signaling mutant bak1 lost more water than wild-type plants and showed ABA insensitivity in stomatal closure. ABA-induced OST1 expression and reactive oxygen species (ROS) production were also impaired in bak1. Unlike direct treatment with H2O2, overexpression of OST1 did not completely rescue the insensitivity of bak1 to ABA. We demonstrated that BAK1 forms a complex with OST1 near the plasma membrane and that the BAK1/OST1 complex is increased in response to ABA in planta. Brassinolide, the most active BR, exerted a negative effect on ABA-induced formation of the BAK1/OST1 complex and OST1 expression. Moreover, we found that BAK1 and ABI1 oppositely regulate OST1 phosphorylation in vitro, and that ABI1 interacts with BAK1 and inhibits the interaction of BAK1 and OST1. Taken together, our results suggest that BAK1 regulates ABA-induced stomatal closure in guard cells.

  14. New 2',6'-dimethyl-L-tyrosine (Dmt) opioid peptidomimetics based on the Aba-Gly scaffold. Development of unique mu-opioid receptor ligands.

    PubMed

    Ballet, Steven; Salvadori, Severo; Trapella, Claudio; Bryant, Sharon D; Jinsmaa, Yunden; Lazarus, Lawrence H; Negri, Lucia; Giannini, Elisa; Lattanzi, Roberta; Tourwé, Dirk; Balboni, Gianfranco

    2006-06-29

    The Aba-Gly scaffold, incorporated into Dmt-Tic ligands (H-Dmt-Tic-Gly-NH-CH2-Ph, H-Dmt-Tic-Gly-NH-Ph, H-Dmt-Tic-NH-CH2-Bid), exhibited mixed micro/delta or delta opioid receptor activities with micro agonism. Substitution of Tic by Aba-Gly coupled to -NH-CH2-Ph (1), -NH-Ph (2), or -Bid (Bid=1H-benzimidazole-2-yl) (3) shifted affinity (Ki(micro)=0.46, 1.48, and 19.9 nM, respectively), selectivity, and bioactivity to micro-opioid receptors. These compounds represent templates for a new class of lead opioid agonists that are easily synthesized and suitable for therapeutic pain relief.

  15. A Glycine soja ABA-responsive receptor-like cytoplasmic kinase, GsRLCK, positively controls plant tolerance to salt and drought stresses.

    PubMed

    Sun, XiaoLi; Sun, Mingzhe; Luo, Xiao; Ding, XiaoDong; Ji, Wei; Cai, Hua; Bai, Xi; Liu, XiaoFei; Zhu, YanMing

    2013-06-01

    Receptor such as protein kinases are proposed to work as sensors to initiate signaling cascades in higher plants. However, little is known about the precise functions of receptor such as protein kinases in abiotic stress response in plants, especially in wild soybean. Here, we focused on characterization of the biological functions of a receptor-like cytoplasmic serine/threonine protein kinase gene, GsRLCK, which was previously identified as a putative salt-alkali stress-related gene from the transcriptome profiles of Glycine soja. Bioinformatic analysis showed that GsRLCK protein contained a conserved kinase catalytic domain and two transmembrane domains at the N-terminus, but no typical extracellular domain. Consistently, GsRLCK-eGFP fusion protein was observed on the plasma membrane, but eGFP alone was distributing throughout the cytoplasm in onion epidermal cells. Quantitative real-time PCR analysis revealed the induced expression of GsRLCK by ABA, salt, alkali, and drought stresses. However, the expression levels of GsRLCK seemed to be similar in different tissues, except soybean pod. Phenotypic assays demonstrated that GsRLCK overexpression decreased ABA sensitivity and altered expression levels of ABA-responsive genes. Furthermore, we also found that GsRLCK conferred increased tolerance to salt and drought stresses and increased expression levels of a handful of stress-responsive genes, when overexpressing in Arabidopsis. In a word, we gave exact evidence that GsRLCK was a novel receptor-like cytoplasmic protein kinase and played a crucial role in plant responses to ABA, salt, and drought stresses.

  16. Seed dormancy and ABA signaling

    PubMed Central

    del Carmen Rodríguez-Gacio, María; Matilla-Vázquez, Miguel A

    2009-01-01

    The seed is an important organ in higher plants, it is an important organ for plant survival and species dispersion. The transition between seed dormancy and germination represents a critical stage in the plant life cycle and it is an important ecological and commercial trait. A dynamic balance of synthesis and catabolism of two antagonistic hormones, abscisic acid (ABA) and giberellins (GAs), controls the equilibrium between seed dormancy and germination. Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth. Therefore, the ABA metabolism must be highly regulated at both temporal and spatial levels during phase of dessication tolerance. On the other hand, the ABA levels do not depend exclusively on the seeds because sometimes it becomes a strong sink and imports it from the roots and rhizosphere through the xylem and/or phloem. These events are discussed in depth here. Likewise, the role of some recently characterized genes belonging to seeds of woody species and related to ABA signaling are also included. Finally, although four possible ABA receptors have been reported, not much is known about how they mediate ABA signaling transduction. However, new publications seem to show that almost all these receptors lack several properties to consider them as such. PMID:19875942

  17. Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

    PubMed Central

    Waadt, Rainer; Schroeder, Julian I.

    2016-01-01

    The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

  18. Epigenetic chromatin modifiers in barley: III. Isolation and characterization of the barley GNAT-MYST family of histone acetyltransferases and responses to exogenous ABA.

    PubMed

    Papaefthimiou, Dimitra; Likotrafiti, Eleni; Kapazoglou, Aliki; Bladenopoulos, Konstantinos; Tsaftaris, Athanasios

    2010-01-01

    Histone acetylation is a vital mechanism for the activation of chromatin and the corresponding expression of genes competing the action of histone deacetylation and leading to chromatin inactivation. Histone acetyltransferases (HATs) comprise a superfamily including the GNAT/MYST, CBP and TF(II)250 families. Histone acetyltransferases have been well studied in Arabidopsis but information from agronomically important crops is limited. In the present work three full-length sequences encoding members of the GNAT/MYST family, namely HvMYST, HvELP3 and HvGCN5, respectively, were isolated and characterized from barley (Hordeum vulgare L.), a crop of high economic value. Expression analysis of the barley GNAT/MYST genes revealed significant quantitative differences in different seed developmental stages and between cultivars with varying seed size and weight, suggesting an association of these genes with barley seed development. Furthermore, all three HvGNAT/MYST genes were inducible by the stress-related phytohormone abscisic acid (ABA) involved in seed maturation, dormancy and germination, implying a possible regulation of these genes by ABA, during barley seed development, germination and stress response. PMID:20117010

  19. A new family of insect tyramine receptors.

    PubMed

    Cazzamali, Giuseppe; Klaerke, Dan A; Grimmelikhuijzen, Cornelis J P

    2005-12-16

    The Drosophila Genome Project database contains a gene, CG7431, annotated to be an "unclassifiable biogenic amine receptor." We have cloned this gene and expressed it in Chinese hamster ovary cells. After testing various ligands for G protein-coupled receptors, we found that the receptor was specifically activated by tyramine (EC(50), 5x10(-7)M) and that it showed no cross-reactivity with beta-phenylethylamine, octopamine, dopa, dopamine, adrenaline, noradrenaline, tryptamine, serotonin, histamine, and a library of 20 Drosophila neuropeptides (all tested in concentrations up to 10(-5) or 10(-4)M). The receptor was also expressed in Xenopus oocytes, where it was, again, specifically activated by tyramine with an EC(50) of 3x10(-7)M. Northern blots showed that the receptor is already expressed in 8-hour-old embryos and that it continues to be expressed in all subsequent developmental stages. Adult flies express the receptor both in the head and body (thorax/abdomen) parts. In addition to the Drosophila tyramine receptor gene, CG7431, we found another closely related Drosophila gene, CG16766, that probably also codes for a tyramine receptor. Furthermore, we annotated similar tyramine-like receptor genes in the genomic databases from the malaria mosquito Anopheles gambiae and the honeybee Apis mellifera. These four tyramine or tyramine-like receptors constitute a new receptor family that is phylogenetically distinct from the previously identified insect octopamine/tyramine receptors. The Drosophila tyramine receptor is, to our knowledge, the first cloned insect G protein-coupled receptor that appears to be fully specific for tyramine.

  20. Transcriptional regulation of SlPYL, SlPP2C, and SlSnRK2 gene families encoding ABA signal core components during tomato fruit development and drought stress

    PubMed Central

    Sun, Liang; Wang, Yan-Ping; Chen, Pei; Ren, Jie; Ji, Kai; Li, Qian; Li, Ping; Dai, Sheng-Jie; Leng, Ping

    2011-01-01

    In order to characterize the potential transcriptional regulation of core components of abscisic acid (ABA) signal transduction in tomato fruit development and drought stress, eight SlPYL (ABA receptor), seven SlPP2C (type 2C protein phosphatase), and eight SlSnRK2 (subfamily 2 of SNF1-related kinases) full-length cDNA sequences were isolated from the tomato nucleotide database of NCBI GenBank. All SlPYL, SlPP2C, and SlSnRK2 genes obtained are homologous to Arabidopsis AtPYL, AtPP2C, and AtSnRK2 genes, respectively. Based on phylogenetic analysis, SlPYLs and SlSnRK2s were clustered into three subfamilies/subclasses, and all SlPP2Cs belonged to PP2C group A. Within the SlPYL gene family, SlPYL1, SlPYL2, SlPYL3, and SlPYL6 were the major genes involved in the regulation of fruit development. Among them, SlPYL1 and SlPYL2 were expressed at high levels throughout the process of fruit development and ripening; SlPYL3 was strongly expressed at the immature green (IM) and mature green (MG) stages, while SlPYL6 was expressed strongly at the IM and red ripe (RR) stages. Within the SlPP2C gene family, the expression of SlPP2C, SlPP2C3, and SlPP2C4 increased after the MG stage; SlPP2C1 and SlPP2C5 peaked at the B3 stage, while SlPP2C2 and SlPP2C6 changed little during fruit development. Within the SlSnRK2 gene family, the expression of SlSnRK2.2, SlSnRK2.3, SlSnRK2.4, and SlSnRK2C was higher than that of other members during fruit development. Additionally, most SlPYL genes were down-regulated, while most SlPP2C and SlSnRK2 genes were up-regulated by dehydration in tomato leaf. PMID:21873532

  1. Cloning of new members of heat shock protein HSP101 gene family in wheat (Triticum aestivum (L.) Moench) inducible by heat, dehydration, and ABA(1).

    PubMed

    Campbell, J L; Klueva, N Y; Zheng, H G; Nieto-Sotelo, J; Ho, T D; Nguyen, H T

    2001-01-26

    We have cloned two cDNAs, TaHSP101B and TaHSP101C, encoding two heat stress-inducible members of HSP101/ClpB family in bread wheat (Triticum aestivum (L.) Moench.). Proteins encoded by these cDNAs are highly similar at the primary sequence level and diverged from the previously reported TaHSP101 (designated TaHSP101A) both in the consensus ATP/GTP-binding region II and in the carboxy terminal region. The HSP101 gene was determined to be a single copy gene or a member of a small gene family in hexaploid wheat. Messages encoding HSP101 proteins were inducible by heat stress treatments in both wheat leaves and roots. Accumulation of the TaHSP101C mRNA was less abundant than that of TaHSP101B mRNA. We are showing for the first time that in addition to heat stress, expression of HSP101 mRNAs in wheat leaves was induced by a 2-h dehydration and a treatment with 5x10(-5)M ABA, but not affected by chilling or wounding, indicating that HSP101 proteins may be involved in both heat and drought responses in wheat. PMID:11342108

  2. ABA and cytokinins: challenge and opportunity for plant stress research.

    PubMed

    Verslues, Paul E

    2016-08-01

    Accumulation of the stress hormone abscisic acid (ABA) induces many cellular mechanisms associated with drought resistance. Recent years have seen a rapid advance in our knowledge of how increased ABA levels are perceived by ABA receptors, particularly the PYL/RCAR receptors, but there has been relatively less new information about how ABA accumulation is controlled and matched to stress severity. ABA synthesis and catabolism, conjugation and deconjugation to glucose, and ABA transport all are involved in controlling ABA levels. This highly buffered system of ABA metabolism represents both a challenge and opportunity in developing a mechanistic understanding of how plants detect and respond to drought. Recent data have also shown that direct manipulation of cytokinin levels in transgenic plants has dramatic effect on drought phenotypes and prompted new interest in the role of cytokinins and cytokinin signaling in drought. Both ABA and cytokinins will continue to be major foci of drought research but likely with different trajectories both in terms of basic research and in translational research aimed at increasing plant performance during drought. PMID:26910054

  3. A thermodynamic switch modulates abscisic acid receptor sensitivity

    PubMed Central

    Dupeux, Florine; Santiago, Julia; Betz, Katja; Twycross, Jamie; Park, Sang-Youl; Rodriguez, Lesia; Gonzalez-Guzman, Miguel; Jensen, Malene Ringkjøbing; Krasnogor, Natalio; Blackledge, Martin; Holdsworth, Michael; Cutler, Sean R; Rodriguez, Pedro L; Márquez, José Antonio

    2011-01-01

    Abscisic acid (ABA) is a key hormone regulating plant growth, development and the response to biotic and abiotic stress. ABA binding to pyrabactin resistance (PYR)/PYR1-like (PYL)/Regulatory Component of Abscisic acid Receptor (RCAR) intracellular receptors promotes the formation of stable complexes with certain protein phosphatases type 2C (PP2Cs), leading to the activation of ABA signalling. The PYR/PYL/RCAR family contains 14 genes in Arabidopsis and is currently the largest plant hormone receptor family known; however, it is unclear what functional differentiation exists among receptors. Here, we identify two distinct classes of receptors, dimeric and monomeric, with different intrinsic affinities for ABA and whose differential properties are determined by the oligomeric state of their apo forms. Moreover, we find a residue in PYR1, H60, that is variable between family members and plays a key role in determining oligomeric state. In silico modelling of the ABA activation pathway reveals that monomeric receptors have a competitive advantage for binding to ABA and PP2Cs. This work illustrates how receptor oligomerization can modulate hormonal responses and more generally, the sensitivity of a ligand-dependent signalling system. PMID:21847091

  4. LRP receptor family member associated bone disease.

    PubMed

    Lara-Castillo, N; Johnson, M L

    2015-06-01

    A dozen years ago the identification of causal mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene involved in two rare bone disorders propelled research in the bone field in totally new directions. Since then, there have been an explosion in the number of reports that highlight the role of the Wnt/β-catenin pathway in the regulation of bone homeostasis. In this review we discuss some of the most recent reports (in the past 2 years) highlighting the involvement of the members of the LRP family (LRP5, LRP6, LRP4, and more recently LRP8) in the maintenance of bone and their implications in bone diseases. These reports include records of new single nucleotides polymorphisms (SNPs) and haplotypes that suggest variants in these genes can contribute to subtle variation in bone traits to mutations that give rise to extreme bone phenotypes. All of these serve to further support and reinforce the importance of this tightly regulated pathway in bone. Furthermore, we discuss provocative reports suggesting novel approaches through inhibitors of this pathway to treat rarer diseases such as Osteoporosis-Pseudoglioma Syndrome (OPPG), Osteogenesis Imperfecta (OI), and Sclerosteosis/Van Buchem disease. It is hoped that by understanding the role of each component of the pathway and their involvement in bone diseases that this knowledge will allow us to develop new, more effective therapeutic approaches for more common diseases such as post-menopausal osteoporosis, osteoarthritis, and rheumatoid arthritis as well as these rarer bone diseases.

  5. Calcium-dependent oligomerization of CAR proteins at cell membrane modulates ABA signaling

    PubMed Central

    Diaz, Maira; Sanchez-Barrena, Maria Jose; Gonzalez-Rubio, Juana Maria; Rodriguez, Lesia; Fernandez, Daniel; Antoni, Regina; Yunta, Cristina; Belda-Palazon, Borja; Gonzalez-Guzman, Miguel; Peirats-Llobet, Marta; Menendez, Margarita; Boskovic, Jasminka; Marquez, Jose A.; Rodriguez, Pedro L.; Albert, Armando

    2016-01-01

    Regulation of ion transport in plants is essential for cell function. Abiotic stress unbalances cell ion homeostasis, and plants tend to readjust it, regulating membrane transporters and channels. The plant hormone abscisic acid (ABA) and the second messenger Ca2+ are central in such processes, as they are involved in the regulation of protein kinases and phosphatases that control ion transport activity in response to environmental stimuli. The identification and characterization of the molecular mechanisms underlying the effect of ABA and Ca2+ signaling pathways on membrane function are central and could provide opportunities for crop improvement. The C2-domain ABA-related (CAR) family of small proteins is involved in the Ca2+-dependent recruitment of the pyrabactin resistance 1/PYR1-like (PYR/PYL) ABA receptors to the membrane. However, to fully understand CAR function, it is necessary to define a molecular mechanism that integrates Ca2+ sensing, membrane interaction, and the recognition of the PYR/PYL interacting partners. We present structural and biochemical data showing that CARs are peripheral membrane proteins that functionally cluster on the membrane and generate strong positive membrane curvature in a Ca2+-dependent manner. These features represent a mechanism for the generation, stabilization, and/or specific recognition of membrane discontinuities. Such structures may act as signaling platforms involved in the recruitment of PYR/PYL receptors and other signaling components involved in cell responses to stress. PMID:26719420

  6. LRP Receptor Family Member Associated Bone Disease

    PubMed Central

    Lara-Castillo, N; Johnson, ML

    2015-01-01

    A dozen years ago the identification of causal mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene involved in two rare bone disorders propelled research in the bone field in totally new directions. Since then, there have been an explosion in the number of reports that highlight the role of the Wnt/β-catenin pathway in the regulation of bone homeostasis. In this review we discuss some of the most recent reports (in the past 2 years) highlighting the involvement of the members of the LRP family (LRP5, LRP6, LRP4, and more recently LRP8) in the maintenance of bone and their implications in bone diseases. These reports include records of new single nucleotides polymorphisms (SNPs) and haplotypes that suggest variants in these genes can contribute to subtle variation in bone traits to mutations that give rise to extreme bone phenotypes. All of these serve to further support and reinforce the importance of this tightly regulated pathway in bone. Furthermore, we discuss provocative reports suggesting novel approaches through inhibitors of this pathway to treat rarer diseases such as Osteoporosis-Pseudoglioma Syndrome (OPPG), Osteogenesis Imperfecta (OI), and Sclerosteosis/Van Buchem disease. It is hoped that by understanding the role of each component of the pathway and their involvement in bone diseases that this knowledge will allow us to develop new, more effective therapeutic approaches for more common diseases such as post-menopausal osteoporosis, osteoarthritis, and rheumatoid arthritis as well as these rarer bone diseases. PMID:26048454

  7. A key ABA catabolic gene, OsABA8ox3, is involved in drought stress resistance in rice.

    PubMed

    Cai, Shanlan; Jiang, Guobin; Ye, Nenghui; Chu, Zhizhan; Xu, Xuezhong; Zhang, Jianhua; Zhu, Guohui

    2015-01-01

    Expressions of ABA biosynthesis genes and catabolism genes are generally co-regulated in plant development and responses to environmental stress. Up-regulation of OsNCED3 gene, a key gene in ABA biosynthesis, has been suggested as a way to enhance plant drought resistance but little is known for the role of ABA catabolic genes during drought stress. In this study, we found that OsABA8ox3 was the most highly expressed gene of the OsABA8ox family in rice leaves. Expression of OsABA8ox3 was promptly induced by rehydration after PEG-mimic dehydration, a tendency opposite to the changes of ABA level. We therefore constructed rice OsABA8ox3 silencing (RNA interference, RNAi) and overexpression plants. There were no obvious phenotype differences between the transgenic seedlings and wild type under normal condition. However, OsABA8ox3 RNAi lines showed significant improvement in drought stress tolerance while the overexpression seedlings were hypersensitive to drought stress when compared with wild type in terms of plant survival rates after 10 days of unwatering. Enzyme activity analysis indicated that OsABA8ox3 RNAi plants had higher superoxide dismutase (SOD) and catalase (CAT) activities and less malondialdehyde (MDA) content than those of wild type when the plants were exposed to dehydration treatment, indicating a better anti-oxidative stress capability and less membrane damage. DNA microarray and real-time PCR analysis under dehydration treatment revealed that expressions of a group of stress/drought-related genes, i.e. LEA genes, were enhanced with higher transcript levels in OsABA8ox3 RNAi transgenic seedlings. We therefore conclude that that OsABA8ox3 gene plays an important role in controlling ABA level and drought stress resistance in rice. PMID:25647508

  8. The Human Laminin Receptor is a Member of the Integrin Family of Cell Adhesion Receptors

    NASA Astrophysics Data System (ADS)

    Gehlsen, Kurt R.; Dillner, Lena; Engvall, Eva; Ruoslahti, Erkki

    1988-09-01

    A receptor for the adhesive basement membrane protein, laminin, was isolated from human glioblastoma cells by affinity chromatography on laminin. This receptor has a heterodimeric structure similar to that of receptors for other extracellular matrix proteins such as fibronectin and vitronectin. Incorporation of the laminin receptor into liposomal membranes makes it possible for liposomes to attach to surfaces coated with laminin. The receptor liposomes also attached to some extent to surfaces coated with fibronectin, but not with other matrix proteins. These properties identify the laminin receptor as a member of the integrin family of cell adhesion receptors.

  9. Structural basis and functions of abscisic acid receptors PYLs

    PubMed Central

    Zhang, Xing L.; Jiang, Lun; Xin, Qi; Liu, Yang; Tan, Jian X.; Chen, Zhong Z.

    2015-01-01

    Abscisic acid (ABA) plays a key role in many developmental processes and responses to adaptive stresses in plants. Recently, a new family of nucleocytoplasmic PYR/PYL/RCAR (PYLs) has been identified as bona fide ABA receptors. PYLs together with protein phosphatases type-2C (PP2Cs), Snf1 (Sucrose-non-fermentation 1)-related kinases subfamily 2 (SnRK2s) and downstream substrates constitute the core ABA signaling network. Generally, PP2Cs inactivate SnRK2s kinases by physical interaction and direct dephosphorylation. Upon ABA binding, PYLs change their conformations and then contact and inhibit PP2Cs, thus activating SnRK2s. Here, we reviewed the recent progress in research regarding the structures of the core signaling pathways of ABA, including the (+)-ABA, (−)-ABA and ABA analogs pyrabactin as well as 6AS perception by PYLs, SnRK2s mimicking PYLs in binding PP2Cs. PYLs inhibited PP2Cs in both the presence and absence of ABA and activated SnRK2s. The present review elucidates multiple ABA signal perception and transduction by PYLs, which might shed light on how to design small chemical compounds for improving plant performance in the future. PMID:25745428

  10. Abscisic Acid Analogues That Act as Universal or Selective Antagonists of Phytohormone Receptors.

    PubMed

    Rajagopalan, Nandhakishore; Nelson, Ken M; Douglas, Amy F; Jheengut, Vishal; Alarcon, Idralyn Q; McKenna, Sean A; Surpin, Marci; Loewen, Michele C; Abrams, Suzanne R

    2016-09-13

    The plant hormone abscisic acid (ABA) plays many important roles in controlling plant development and physiology, from flowering to senescence. ABA is now known to exert its effects through a family of soluble ABA receptors, which in Arabidopsis thaliana has 13 members divided into three clades. Homologues of these receptors are present in other plants, also in relatively large numbers. Investigation of the roles of each homologue in mediating the diverse physiological roles of ABA is hampered by this genetic redundancy. We report herein the in vitro screening of a targeted ABA-like analogue library and identification of novel antagonist hits, including the analogue PBI686 that had been developed previously as a probe for identifying ABA-binding proteins. Further in vitro characterization of PBI686 and development of second-generation leads yielded both receptor-selective and universal antagonist hits. In planta assays in different species have demonstrated that these antagonist leads can overcome various ABA-induced physiological changes. While the general antagonists open up a hitherto unexplored avenue for controlling plant growth through inhibition of ABA-regulated physiological processes, the receptor-selective antagonist can be developed into chemical probes to explore the physiological roles of individual receptors.

  11. Abscisic Acid Analogues That Act as Universal or Selective Antagonists of Phytohormone Receptors.

    PubMed

    Rajagopalan, Nandhakishore; Nelson, Ken M; Douglas, Amy F; Jheengut, Vishal; Alarcon, Idralyn Q; McKenna, Sean A; Surpin, Marci; Loewen, Michele C; Abrams, Suzanne R

    2016-09-13

    The plant hormone abscisic acid (ABA) plays many important roles in controlling plant development and physiology, from flowering to senescence. ABA is now known to exert its effects through a family of soluble ABA receptors, which in Arabidopsis thaliana has 13 members divided into three clades. Homologues of these receptors are present in other plants, also in relatively large numbers. Investigation of the roles of each homologue in mediating the diverse physiological roles of ABA is hampered by this genetic redundancy. We report herein the in vitro screening of a targeted ABA-like analogue library and identification of novel antagonist hits, including the analogue PBI686 that had been developed previously as a probe for identifying ABA-binding proteins. Further in vitro characterization of PBI686 and development of second-generation leads yielded both receptor-selective and universal antagonist hits. In planta assays in different species have demonstrated that these antagonist leads can overcome various ABA-induced physiological changes. While the general antagonists open up a hitherto unexplored avenue for controlling plant growth through inhibition of ABA-regulated physiological processes, the receptor-selective antagonist can be developed into chemical probes to explore the physiological roles of individual receptors. PMID:27523384

  12. Arabidopsis PYL8 Plays an Important Role for ABA Signaling and Drought Stress Responses.

    PubMed

    Lim, Chae Woo; Baek, Woonhee; Han, Sang-Wook; Lee, Sung Chul

    2013-12-01

    Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress. PMID:25288979

  13. A family of photoswitchable NMDA receptors

    PubMed Central

    Berlin, Shai; Szobota, Stephanie; Reiner, Andreas; Carroll, Elizabeth C; Kienzler, Michael A; Guyon, Alice; Xiao, Tong; Trauner, Dirk; Isacoff, Ehud Y

    2016-01-01

    NMDA receptors, which regulate synaptic strength and are implicated in learning and memory, consist of several subtypes with distinct subunit compositions and functional properties. To enable spatiotemporally defined, rapid and reproducible manipulation of function of specific subtypes, we engineered a set of photoswitchable GluN subunits ('LiGluNs'). Photo-agonism of GluN2A or GluN2B elicits an excitatory drive to hippocampal neurons that can be shaped in time to mimic synaptic activation. Photo-agonism of GluN2A at single dendritic spines evokes spine-specific calcium elevation and expansion, the morphological correlate of LTP. Photo-antagonism of GluN2A alone, or in combination with photo-antagonism of GluN1a, reversibly blocks excitatory synaptic currents, prevents the induction of long-term potentiation and prevents spine expansion. In addition, photo-antagonism in vivo disrupts synaptic pruning of developing retino-tectal projections in larval zebrafish. By providing precise and rapidly reversible optical control of NMDA receptor subtypes, LiGluNs should help unravel the contribution of specific NMDA receptors to synaptic transmission, integration and plasticity. DOI: http://dx.doi.org/10.7554/eLife.12040.001 PMID:26929991

  14. Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

    SciTech Connect

    Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M.H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun; Yong, Eu-Leong; Cutler, Sean; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

    2014-10-02

    Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.

  15. Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

    PubMed Central

    Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M. H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun; Yong, Eu-Leong; Cutler, Sean; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

    2013-01-01

    Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites. PMID:22116026

  16. Signal transduction through the IL-4 and insulin receptor families.

    PubMed

    Wang, L M; Keegan, A; Frankel, M; Paul, W E; Pierce, J H

    1995-07-01

    Activation of tyrosine kinase-containing receptors and intracellular tyrosine kinases by ligand stimulation is known to be crucial for mediating initial and subsequent events involved in mitogenic signal transduction. Receptors for insulin and insulin-like growth factor 1 (IGF-1) contain cytoplasmic tyrosine kinase domains that undergo autophosphorylation upon ligand stimulation. Activation of these receptors also leads to pronounced and rapid tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1) in cells of connective tissue origin. A related substrate, designated 4PS, is similarly phosphorylated by insulin and IGF-1 stimulation in many hematopoietic cell types. IRS-1 and 4PS possess a number of tyrosine phosphorylation sites that are within motifs that bind specific SH2-containing molecules known to be involved in mitogenic signaling such as PI-3 kinase, SHPTP-2 (Syp) and Grb-2. Thus, they appear to act as docking substrates for a variety of signaling molecules. The majority of hematopoietic cytokines bind to receptors that do not possess intrinsic kinase activity, and these receptors have been collectively termed as members of the hematopoietin receptor superfamily. Despite their lack of tyrosine kinase domains, stimulation of these receptors has been demonstrated to activate intracellular kinases leading to tyrosine phosphorylation of multiple substrates. Recent evidence has demonstrated that activation of different members of the Janus family of tyrosine kinases is involved in mediating tyrosine phosphorylation events by specific cytokines. Stimulation of the interleukin 4 (IL-4) receptor, a member of the hematopoietin receptor superfamily, is thought to result in activation of Jak1, Jak3, and/or Fes tyrosine kinases.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    SciTech Connect

    Melcher, Karsten; Ng, Ley-Moy; Zhou, X Edward; Soon, Fen-Fen; Xu, Yong; Suino-Powell, Kelly M; Park, Sang-Youl; Weiner, Joshua J; Fujii, Hiroaki; Chinnusamy, Viswanathan; Kovach, Amanda; Li, Jun; Wang, Yonghong; Li, Jiayang; Peterson, Francis C; Jensen, Davin R; Yong, Eu-Leong; Volkman, Brian F; Cutler, Sean R; Zhu, Jian-Kang; Xu, H Eric

    2010-01-12

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved β-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.

  18. ABA Regulates Subcellular Redistribution of OsABI-LIKE2, a Negative Regulator in ABA Signaling, to Control Root Architecture and Drought Resistance in Oryza sativa.

    PubMed

    Li, Chengxiang; Shen, Hongyun; Wang, Tao; Wang, Xuelu

    2015-12-01

    The phytohormone ABA is a key stress signal in plants. Although the identification of ABA receptors led to significant progress in understanding the Arabidopsis ABA signaling pathway, there are still many unsolved mysteries regarding ABA signaling in monocots, such as rice. Here, we report that a rice ortholog of AtABI1 and AtABI2, named OsABI-LIKE2 (OsABIL2), plays a negative role in rice ABA signaling. Overexpression of OsABIL2 not only led to ABA insensitivity, but also significantly altered plant developmental phenotypes, including stomatal density and root architecture, which probably caused the hypersensitivity to drought stress. OsABIL2 interacts with OsPYL1, SAPK8 and SAPK10 both in vitro and in vivo, and the phosphatase activity of OsABIL2 was repressed by ABA-bound OsPYL1. However, unlike many other solely nuclear-localized clade A type 2C protein phosphatases (PP2Cs), OsABIL2 is localized in both the nucleus and cytosol. Furthermore, OsABIL2 interacts with and co-localized with OsPYL1 mainly in the cytosol, and ABA treatment regulates the nucleus-cytosol distribution of OsABIL2, suggesting a different mechanism for the activation of ABA signaling. Taken together, this study provides significant insights into rice ABA signaling and indicates the important role of OsABIL2 in regulating root development. PMID:26491145

  19. Arabidopsis DREB2C modulates ABA biosynthesis during germination.

    PubMed

    Je, Jihyun; Chen, Huan; Song, Chieun; Lim, Chae Oh

    2014-09-12

    Plant dehydration-responsive element binding factors (DREBs) are transcriptional regulators of the APETELA2/Ethylene Responsive element-binding Factor (AP2/ERF) family that control expression of abiotic stress-related genes. We show here that under conditions of mild heat stress, constitutive overexpression seeds of transgenic DREB2C overexpression Arabidopsis exhibit delayed germination and increased abscisic acid (ABA) content compared to untransformed wild-type (WT). Treatment with fluridone, an inhibitor of the ABA biosynthesis abrogated these effects. Expression of an ABA biosynthesis-related gene, 9-cis-epoxycarotenoid dioxygenase 9 (NCED9) was up-regulated in the DREB2C overexpression lines compared to WT. DREB2C was able to trans-activate expression of NCED9 in Arabidopsis leaf protoplasts in vitro. Direct and specific binding of DREB2C to a complete DRE on the NCED9 promoter was observed in electrophoretic mobility shift assays. Exogenous ABA treatment induced DREB2C expression in germinating seeds of WT. Vegetative growth of transgenic DREB2C overexpression lines was more strongly inhibited by exogenous ABA compared to WT. These results suggest that DREB2C is a stress- and ABA-inducible gene that acts as a positive regulator of ABA biosynthesis in germinating seeds through activating NCED9 expression.

  20. Receptor Specificity of the Fibroblast Growth Factor Family

    PubMed Central

    Zhang, Xiuqin; Ibrahimi, Omar A.; Olsen, Shaun K.; Umemori, Hisashi; Mohammadi, Moosa; Ornitz, David M.

    2007-01-01

    In mammals, fibroblast growth factors (FGFs) are encoded by 22 genes. FGFs bind and activate alternatively spliced forms of four tyrosine kinase FGF receptors (FGFRs 1–4). The spatial and temporal expression patterns of FGFs and FGFRs and the ability of specific ligand-receptor pairs to actively signal are important factors regulating FGF activity in a variety of biological processes. FGF signaling activity is regulated by the binding specificity of ligands and receptors and is modulated by extrinsic cofactors such as heparan sulfate proteoglycans. In previous studies, we have engineered BaF3 cell lines to express the seven principal FGFRs and used these cell lines to determine the receptor binding specificity of FGFs 1–9 by using relative mitogenic activity as the readout. Here we have extended these semiquantitative studies to assess the receptor binding specificity of the remaining FGFs 10–23. This study completes the mitogenesis-based comparison of receptor specificity of the entire FGF family under standard conditions and should help in interpreting and predicting in vivo biological activity. PMID:16597617

  1. The venus kinase receptor (VKR) family: structure and evolution

    PubMed Central

    2013-01-01

    Background Receptor tyrosine kinases (RTK) form a family of transmembrane proteins widely conserved in Metazoa, with key functions in cell-to-cell communication and control of multiple cellular processes. A new family of RTK named Venus Kinase Receptor (VKR) has been described in invertebrates. The VKR receptor possesses a Venus Fly Trap (VFT) extracellular module, a bilobate structure that binds small ligands to induce receptor kinase activity. VKR was shown to be highly expressed in the larval stages and gonads of several invertebrates, suggesting that it could have functions in development and/or reproduction. Results Analysis of recent genomic data has allowed us to extend the presence of VKR to five bilaterian phyla (Platyhelminthes, Arthropoda, Annelida, Mollusca, Echinodermata) as well as to the Cnidaria phylum. The presence of NveVKR in the early-branching metazoan Nematostella vectensis suggested that VKR arose before the bilaterian radiation. Phylogenetic and gene structure analyses showed that the 40 receptors identified in 36 animal species grouped monophyletically, and likely evolved from a common ancestor. Multiple alignments of tyrosine kinase (TK) and VFT domains indicated their important level of conservation in all VKRs identified up to date. We showed that VKRs had inducible activity upon binding of extracellular amino-acids and molecular modeling of the VFT domain confirmed the structure of the conserved amino-acid binding site. Conclusions This study highlights the presence of VKR in a large number of invertebrates, including primitive metazoans like cnidarians, but also its absence from nematodes and chordates. This little-known RTK family deserves to be further explored in order to determine its evolutionary origin, its possible interest for the emergence and specialization of Metazoa, and to understand its function in invertebrate development and/or reproductive biology. PMID:23721482

  2. Signaling Receptors for TGF-β Family Members.

    PubMed

    Heldin, Carl-Henrik; Moustakas, Aristidis

    2016-01-01

    Transforming growth factor β (TGF-β) family members signal via heterotetrameric complexes of type I and type II dual specificity kinase receptors. The activation and stability of the receptors are controlled by posttranslational modifications, such as phosphorylation, ubiquitylation, sumoylation, and neddylation, as well as by interaction with other proteins at the cell surface and in the cytoplasm. Activation of TGF-β receptors induces signaling via formation of Smad complexes that are translocated to the nucleus where they act as transcription factors, as well as via non-Smad pathways, including the Erk1/2, JNK and p38 MAP kinase pathways, and the Src tyrosine kinase, phosphatidylinositol 3'-kinase, and Rho GTPases. PMID:27481709

  3. Targeting a family B GPCR/RAMP receptor complex: CGRP receptor antagonists and migraine

    PubMed Central

    Moore, Eric L; Salvatore, Christopher A

    2012-01-01

    The clinical effectiveness of antagonizing the calcitonin gene-related peptide (CGRP) receptor for relief of migraine pain has been clearly demonstrated, but the road to the development of these small molecule antagonists has been daunting. The key hurdle that needed to be overcome was the CGRP receptor itself. The vast majority of the current antagonists recognize similar epitopes on the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1). RAMP1 is a relatively small, single, transmembrane-spanning protein and along with the G-protein-coupled receptor CLR comprise a functional CGRP receptor. The tri-helical extracellular domain of RAMP1 plays a key role in the high affinity binding of CGRP receptor antagonists and drives their species-selective pharmacology. Over the years, a significant amount of mutagenesis data has been generated to identify specific amino acids or regions within CLR and RAMP1 that are critical to antagonist binding and has directed attention to the CLR/RAMP1 extracellular domain (ECD) complex. Recently, the crystal structure of the CGRP receptor ECD has been elucidated and not only reinforces the early mutagenesis data, but provides critical insight into the molecular mechanism of CGRP receptor antagonism. This review will highlight the drug design hurdles that must be overcome to meet the desired potency, selectivity and pharmacokinetic profile while retaining drug-like properties. Although the development of these antagonists has proved challenging, blocking the CGRP receptor may one day represent a new way to manage migraine and offer hope to migraine sufferers. LINKED ARTICLES This article is part of a themed section on Secretin Family (Class B) G Protein-Coupled Receptors. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.166.issue-1 PMID:21871019

  4. Recent progresses in identifying nuclear receptors and their families.

    PubMed

    Xiao, Xuan; Wang, Pu; Chou, Kuo-Chen

    2013-01-01

    Nuclear receptors (NRs) are members of a large superfamily of evolutionarily related DNA-binding transcription factors. They regulate diverse functions, such as homeostasis, reproduction, development and metabolism. As nuclear receptors bind small molecules that can easily be modified by drug design, and control functions associated with major diseases (e.g. cancer, osteoporosis and diabetes), they are promising pharmacological targets. According to their different action mechanisms or functions, NR superfamily has been classified into seven families: NR1 (thyroid hormone like), NR2 (HNF4-like), NR3 (estrogen like), NR4 (nerve growth factor IB-like), NR5 (fushi tarazu-F1 like), NR6 (germ cell nuclear factor like), and NR0 (knirps or DAX like). With the avalanche of protein sequences generated in the postgenomic age, Scientists are facing the following challenging problems. Given an uncharacterized protein sequence, how can we identify whether it is a nuclear receptor? If it is, what family even subfamily it belongs to? To address these problems, many cheminformatics tools have been developed for nuclear receptor prediction. The current review is mainly focused on this field, including the functions, computational methods and limitations of these tools. PMID:23647541

  5. ABD1 is an Arabidopsis DCAF substrate receptor for CUL4-DDB1-based E3 ligases that acts as a negative regulator of abscisic acid signaling.

    PubMed

    Seo, Kyoung-In; Lee, Jae-Hoon; Nezames, Cynthia D; Zhong, Shangwei; Song, Eunyoung; Byun, Myung-Ok; Deng, Xing Wang

    2014-02-01

    Members of the DDB1-CUL4-associated factors (DCAFs) family directly bind to DAMAGED DNA BINDING PROTEIN1 (DDB1) and function as the substrate receptors in CULLIN4-based E3 (CUL4) ubiquitin ligases, which regulate the selective ubiquitination of proteins. Here, we describe a DCAF protein, ABD1 (for ABA-hypersensitive DCAF1), that negatively regulates abscisic acid (ABA) signaling in Arabidopsis thaliana. ABD1 interacts with DDB1 in vitro and in vivo, indicating that it likely functions as a CUL4 E3 ligase substrate receptor. ABD1 expression is induced by ABA, and mutations in ABD1 result in ABA- and NaCl-hypersensitive phenotypes. Loss of ABD1 leads to hyperinduction of ABA-responsive genes and higher accumulation of the ABA-responsive transcription factor ABA INSENSITIVE5 (ABI5), hypersensitivity to ABA during seed germination and seedling growth, enhanced stomatal closure, reduced water loss, and, ultimately, increased drought tolerance. ABD1 directly interacts with ABI5 in yeast two-hybrid assays and associates with ABI5 in vivo by coimmunoprecipitation, and the interaction was found in the nucleus by bimolecular fluorescence complementation. Furthermore, loss of ABD1 results in a retardation of ABI5 degradation by the 26S proteasome. Taken together, these data suggest that the DCAF-CUL4 E3 ubiquitin ligase assembled with ABD1 is a negative regulator of ABA responses by directly binding to and affecting the stability of ABI5 in the nucleus. PMID:24563203

  6. Type One Protein Phosphatase 1 and Its Regulatory Protein Inhibitor 2 Negatively Regulate ABA Signaling

    PubMed Central

    Zhao, Yang; Xie, Shaojun; Batelli, Giorgia; Wang, Bangshing; Duan, Cheng-Guo; Wang, Xingang; Xing, Lu; Lei, Mingguang; Yan, Jun; Zhu, Xiaohong; Zhu, Jian-Kang

    2016-01-01

    The phytohormone abscisic acid (ABA) regulates plant growth, development and responses to biotic and abiotic stresses. The core ABA signaling pathway consists of three major components: ABA receptor (PYR1/PYLs), type 2C Protein Phosphatase (PP2C) and SNF1-related protein kinase 2 (SnRK2). Nevertheless, the complexity of ABA signaling remains to be explored. To uncover new components of ABA signal transduction pathways, we performed a yeast two-hybrid screen for SnRK2-interacting proteins. We found that Type One Protein Phosphatase 1 (TOPP1) and its regulatory protein, At Inhibitor-2 (AtI-2), physically interact with SnRK2s and also with PYLs. TOPP1 inhibited the kinase activity of SnRK2.6, and this inhibition could be enhanced by AtI-2. Transactivation assays showed that TOPP1 and AtI-2 negatively regulated the SnRK2.2/3/6-mediated activation of the ABA responsive reporter gene RD29B, supporting a negative role of TOPP1 and AtI-2 in ABA signaling. Consistent with these findings, topp1 and ati-2 mutant plants displayed hypersensitivities to ABA and salt treatments, and transcriptome analysis of TOPP1 and AtI-2 knockout plants revealed an increased expression of multiple ABA-responsive genes in the mutants. Taken together, our results uncover TOPP1 and AtI-2 as negative regulators of ABA signaling. PMID:26943172

  7. A Putative PP2C-Encoding Gene Negatively Regulates ABA Signaling in Populus euphratica

    PubMed Central

    Chen, Jinhuan; Zhang, Dongzhi; Zhang, Chong; Xia, Xinli; Yin, Weilun; Tian, Qianqian

    2015-01-01

    A PP2C homolog gene was cloned from the drought-treated cDNA library of Populus euphratica. Multiple sequence alignment analysis suggested that the gene is a potential ortholog of HAB1. The expression of this HAB1 ortholog (PeHAB1) was markedly induced by drought and moderately induced by ABA. To characterize its function in ABA signaling, we generated transgenic Arabidopsis thaliana plants overexpressing this gene. Transgenic lines exhibited reduced responses to exogenous ABA and reduced tolerance to drought compared to wide-type lines. Yeast two-hybrid analyses indicated that PeHAB1 could interact with the ABA receptor PYL4 in an ABA-independent manner. Taken together; these results indicated that PeHAB1 is a new negative regulator of ABA responses in poplar. PMID:26431530

  8. An activation switch in the rhodopsin family of G protein-coupled receptors: the thyrotropin receptor.

    PubMed

    Urizar, Eneko; Claeysen, Sylvie; Deupí, Xavier; Govaerts, Cedric; Costagliola, Sabine; Vassart, Gilbert; Pardo, Leonardo

    2005-04-29

    We aimed at understanding molecular events involved in the activation of a member of the G protein-coupled receptor family, the thyrotropin receptor. We have focused on the transmembrane region and in particular on a network of polar interactions between highly conserved residues. Using molecular dynamics simulations and site-directed mutagenesis techniques we have identified residue Asn-7.49, of the NPxxY motif of TM 7, as a molecular switch in the mechanism of thyrotropin receptor (TSHr) activation. Asn-7.49 appears to adopt two different conformations in the inactive and active states. These two states are characterized by specific interactions between this Asn and polar residues in the transmembrane domain. The inactive gauche+ conformation is maintained by interactions with residues Thr-6.43 and Asp-6.44. Mutation of these residues into Ala increases the constitutive activity of the receptor by factors of approximately 14 and approximately 10 relative to wild type TSHr, respectively. Upon receptor activation Asn-7.49 adopts the trans conformation to interact with Asp-2.50 and a putatively charged residue that remains to be identified. In addition, the conserved Leu-2.46 of the (N/S)LxxxD motif also plays a significant role in restraining the receptor in the inactive state because the L2.46A mutation increases constitutive activity by a factor of approximately 13 relative to wild type TSHr. As residues Leu-2.46, Asp-2.50, and Asn-7.49 are strongly conserved, this molecular mechanism of TSHr activation can be extended to other members of the rhodopsin-like family of G protein-coupled receptors.

  9. Evolution of the protease-activated receptor family in vertebrates

    PubMed Central

    JIN, MIN; YANG, HAI-WEI; TAO, AI-LIN; WEI, JI-FU

    2016-01-01

    Belonging to the G protein-coupled receptor (GPcr) family, the protease-activated receptors (Pars) consist of 4 members, PAR1-4. PARs mediate the activation of cells via thrombin, serine and other proteases. Such protease-triggered signaling events are thought to be critical for hemostasis, thrombosis and other normal pathological processes. In the present study, we examined the evolution of PARs by analyzing phylogenetic trees, chromosome location, selective pressure and functional divergence based on the 169 functional gene alignment sequences from 57 vertebrate gene sequences. We found that the 4 PARs originated from 4 invertebrate ancestors by phylogenetic trees analysis. The selective pressure results revealed that only PAR1 appeared by positive selection during its evolution, while the other PAR members did not. In addition, we noticed that although these PARs evolved separately, the results of functional divergence indicated that their evolutional rates were similar and their functions did not significantly diverge. The findings of our study provide valuable insight into the evolutionary history of the vertebrate PAR family. PMID:26820116

  10. ABA-HYPERSENSITIVE BTB/POZ PROTEIN 1 functions as a negative regulator in ABA-mediated inhibition of germination in Arabidopsis.

    PubMed

    Kim, Hani; Kim, Soon-Hee; Seo, Dong Hye; Chung, Sunglan; Kim, Sang-Woo; Lee, Jeong-Soo; Kim, Woo Taek; Lee, Jae-Hoon

    2016-02-01

    To elucidate the contribution of CRL3-ABA-mediated responses, we attempted to find CRL3 substrate receptors involved in ABA signaling. One gene named ABA-HYPERSENSITIVE BTB/POZ PROTEIN 1 (AHT1) was upregulated more than 2.5 times by ABA, and its coding region possessed a BTB/POZ domain, which is the common feature of CRL3 substrate receptors. Loss of AHT1 led to retardation of the germination process, not inhibition of root growth. AHT1 transcripts also increased in response to mannitol, NaCl and drought treatments at the seedling stage and in dry seeds. High expression of AHT1 in dry seeds was inhibited by the defect of ABA signaling components such as ABI1, ABI3 and SRKs indicating that the expression of AHT1 is dependent on ABA signaling. Among bZIP transcription factors participating in ABA signaling, the losses of ABI5/DPBF1, AREB1/ABF2, EEL/DPBF4 and DPBF2/bZIP67 resulted in reduced AHT1 expression, showing that these transcription factors play a positive role in ABA-induced AHT1 expression. While loss of AHT1 did not affect the expression pattern of NCED3, ABI2, SRKs and AREB/ABF genes, it led to hyperinduction of ABI5/DPBF genes such as ABI5/DPBF1, EEL/DPBF4 and AREB3/DPBF3, which are mainly involved in seed development and germination, as well as ABA-inducible genes transactivated by ABI5. Overall, these findings indicate that AHT1 negatively regulates ABA-mediated inhibition of germination, possibly by repressing the expression of a subset of ABI5/DPBF subfamily genes, and that AHT1 may be regulated by a negative feedback process through its linkage with a part of ABI5/DPBF proteins. PMID:26667153

  11. Potent and selective activation of abscisic acid receptors in vivo by mutational stabilization of their agonist-bound conformation

    PubMed Central

    Mosquna, Assaf; Peterson, Francis C.; Park, Sang-Youl; Lozano-Juste, Jorge; Volkman, Brian F.; Cutler, Sean R.

    2011-01-01

    Pyrabactin resistance (PYR) 1 and its relatives belong to a family of soluble abscisic acid (ABA) receptors that inhibit type 2C protein phosphatases (PP2C) when in their agonist-stabilized conformation. Given their switch-like properties, we envisioned that mutations that stabilize their agonist-bound conformation could be used to activate signaling in vivo. To identify such mutations, we subjected PYR1 to site-saturation mutagenesis at 39 highly conserved residues that participate in ABA or PP2C contacts. All 741 possible single amino acid substitutions at these sites were tested to identify variants that increase basal PYR1-PP2C interactions, which uncovered activating mutations in 10 residues that preferentially cluster in PYR1's gate loop and C-terminal helix. The mutations cause measurable but incomplete receptor activation in vitro; however, specific triple and quadruple mutant combinations were constructed that promote an agonist-bound conformation, as measured by heteronuclear single quantum coherence NMR, and lead to full receptor activation. Moreover, these mutations retain functionality when introduced into divergent family members, and can therefore be used to dissect individual receptor function in vivo, which has been problematic because of redundancy and family size. Expression of activated PYL2 in Arabidopsis seeds activates ABA signaling by a number of measures: modulation of ABA-regulated gene expression, induction of hyperdormancy, and suppression of ABA deficiency phenotypes in the aba2-1 mutant. Our results set the stage for systematic gain-of-function studies of PYR1 and related ABA receptors and reveal that, despite the large number of receptors, activation of a single receptor is sufficient to activate signaling in planta. PMID:22139369

  12. Activation of family C G-protein-coupled receptors by the tripeptide glutathione.

    PubMed

    Wang, Minghua; Yao, Yi; Kuang, Donghui; Hampson, David R

    2006-03-31

    The Family C G-protein-coupled receptors include the metabotropic glutamate receptors, the gamma-aminobutyric acid, type B (GABAB) receptor, the calcium-sensing receptor (CaSR), which participates in the regulation of calcium homeostasis in the body, and a diverse group of sensory receptors that encompass the amino acid-activated fish 5.24 chemosensory receptor, the mammalian T1R taste receptors, and the V2R pheromone receptors. A common feature of Family C receptors is the presence of an amino acid binding site. In this study, a preliminary in silico analysis of the size and shape of the amino acid binding pocket in selected Family C receptors suggested that some members of this family could accommodate larger ligands such as peptides. Subsequent screening and docking experiments identified GSH as a potential ligand or co-ligand at the fish 5.24 receptor and the rat CaSR. These in silico predictions were confirmed using an [3H]GSH radioligand binding assay and a fluorescence-based functional assay performed on wild-type and chimeric receptors. Glutathione was shown to act as an orthosteric agonist at the 5.24 receptor and as a potent enhancer of calcium-induced activation of the CaSR. Within the mammalian receptors, this effect was specific to the CaSR because GSH neither directly activated nor potentiated other Family C receptors including GPRC6A (the putative mammalian homolog of the fish 5.24 receptor), the metabotropic glutamate receptors, or the GABAB receptor. Our findings reveal a potential new role for GSH and suggest that this peptide may act as an endogenous modulator of the CaSR in the parathyroid gland where this receptor is known to control the release of parathyroid hormone, and in other tissues such as the brain and gastrointestinal tract where the role of the calcium receptor appears to subserve other, as yet unknown, physiological functions. PMID:16455645

  13. C2-domain abscisic acid-related proteins mediate the interaction of PYR/PYL/RCAR abscisic acid receptors with the plasma membrane and regulate abscisic acid sensitivity in Arabidopsis.

    PubMed

    Rodriguez, Lesia; Gonzalez-Guzman, Miguel; Diaz, Maira; Rodrigues, Americo; Izquierdo-Garcia, Ana C; Peirats-Llobet, Marta; Fernandez, Maria A; Antoni, Regina; Fernandez, Daniel; Marquez, Jose A; Mulet, Jose M; Albert, Armando; Rodriguez, Pedro L

    2014-12-01

    Membrane-delimited abscisic acid (ABA) signal transduction plays a critical role in early ABA signaling, but the molecular mechanisms linking core signaling components to the plasma membrane are unclear. We show that transient calcium-dependent interactions of PYR/PYL ABA receptors with membranes are mediated through a 10-member family of C2-domain ABA-related (CAR) proteins in Arabidopsis thaliana. Specifically, we found that PYL4 interacted in an ABA-independent manner with CAR1 in both the plasma membrane and nucleus of plant cells. CAR1 belongs to a plant-specific gene family encoding CAR1 to CAR10 proteins, and bimolecular fluorescence complementation and coimmunoprecipitation assays showed that PYL4-CAR1 as well as other PYR/PYL-CAR pairs interacted in plant cells. The crystal structure of CAR4 was solved, which revealed that, in addition to a classical calcium-dependent lipid binding C2 domain, a specific CAR signature is likely responsible for the interaction with PYR/PYL receptors and their recruitment to phospholipid vesicles. This interaction is relevant for PYR/PYL function and ABA signaling, since different car triple mutants affected in CAR1, CAR4, CAR5, and CAR9 genes showed reduced sensitivity to ABA in seedling establishment and root growth assays. In summary, we identified PYR/PYL-interacting partners that mediate a transient Ca(2+)-dependent interaction with phospholipid vesicles, which affects PYR/PYL subcellular localization and positively regulates ABA signaling. PMID:25465408

  14. C2-domain abscisic acid-related proteins mediate the interaction of PYR/PYL/RCAR abscisic acid receptors with the plasma membrane and regulate abscisic acid sensitivity in Arabidopsis.

    PubMed

    Rodriguez, Lesia; Gonzalez-Guzman, Miguel; Diaz, Maira; Rodrigues, Americo; Izquierdo-Garcia, Ana C; Peirats-Llobet, Marta; Fernandez, Maria A; Antoni, Regina; Fernandez, Daniel; Marquez, Jose A; Mulet, Jose M; Albert, Armando; Rodriguez, Pedro L

    2014-12-01

    Membrane-delimited abscisic acid (ABA) signal transduction plays a critical role in early ABA signaling, but the molecular mechanisms linking core signaling components to the plasma membrane are unclear. We show that transient calcium-dependent interactions of PYR/PYL ABA receptors with membranes are mediated through a 10-member family of C2-domain ABA-related (CAR) proteins in Arabidopsis thaliana. Specifically, we found that PYL4 interacted in an ABA-independent manner with CAR1 in both the plasma membrane and nucleus of plant cells. CAR1 belongs to a plant-specific gene family encoding CAR1 to CAR10 proteins, and bimolecular fluorescence complementation and coimmunoprecipitation assays showed that PYL4-CAR1 as well as other PYR/PYL-CAR pairs interacted in plant cells. The crystal structure of CAR4 was solved, which revealed that, in addition to a classical calcium-dependent lipid binding C2 domain, a specific CAR signature is likely responsible for the interaction with PYR/PYL receptors and their recruitment to phospholipid vesicles. This interaction is relevant for PYR/PYL function and ABA signaling, since different car triple mutants affected in CAR1, CAR4, CAR5, and CAR9 genes showed reduced sensitivity to ABA in seedling establishment and root growth assays. In summary, we identified PYR/PYL-interacting partners that mediate a transient Ca(2+)-dependent interaction with phospholipid vesicles, which affects PYR/PYL subcellular localization and positively regulates ABA signaling.

  15. C2-Domain Abscisic Acid-Related Proteins Mediate the Interaction of PYR/PYL/RCAR Abscisic Acid Receptors with the Plasma Membrane and Regulate Abscisic Acid Sensitivity in Arabidopsis[C][W

    PubMed Central

    Rodriguez, Lesia; Diaz, Maira; Rodrigues, Americo; Izquierdo-Garcia, Ana C.; Peirats-Llobet, Marta; Fernandez, Maria A.; Antoni, Regina; Fernandez, Daniel; Marquez, Jose A.; Mulet, Jose M.; Albert, Armando; Rodriguez, Pedro L.

    2014-01-01

    Membrane-delimited abscisic acid (ABA) signal transduction plays a critical role in early ABA signaling, but the molecular mechanisms linking core signaling components to the plasma membrane are unclear. We show that transient calcium-dependent interactions of PYR/PYL ABA receptors with membranes are mediated through a 10-member family of C2-domain ABA-related (CAR) proteins in Arabidopsis thaliana. Specifically, we found that PYL4 interacted in an ABA-independent manner with CAR1 in both the plasma membrane and nucleus of plant cells. CAR1 belongs to a plant-specific gene family encoding CAR1 to CAR10 proteins, and bimolecular fluorescence complementation and coimmunoprecipitation assays showed that PYL4-CAR1 as well as other PYR/PYL-CAR pairs interacted in plant cells. The crystal structure of CAR4 was solved, which revealed that, in addition to a classical calcium-dependent lipid binding C2 domain, a specific CAR signature is likely responsible for the interaction with PYR/PYL receptors and their recruitment to phospholipid vesicles. This interaction is relevant for PYR/PYL function and ABA signaling, since different car triple mutants affected in CAR1, CAR4, CAR5, and CAR9 genes showed reduced sensitivity to ABA in seedling establishment and root growth assays. In summary, we identified PYR/PYL-interacting partners that mediate a transient Ca2+-dependent interaction with phospholipid vesicles, which affects PYR/PYL subcellular localization and positively regulates ABA signaling. PMID:25465408

  16. Structural, signalling and regulatory properties of the group I metabotropic glutamate receptors: prototypic family C G-protein-coupled receptors.

    PubMed Central

    Hermans, E; Challiss, R A

    2001-01-01

    In 1991 a new type of G-protein-coupled receptor (GPCR) was cloned, the type 1a metabotropic glutamate (mGlu) receptor, which, despite possessing the defining seven-transmembrane topology of the GPCR superfamily, bore little resemblance to the growing number of other cloned GPCRs. Subsequent studies have shown that there are eight mammalian mGlu receptors that, together with the calcium-sensing receptor, the GABA(B) receptor (where GABA is gamma-aminobutyric acid) and a subset of pheromone, olfactory and taste receptors, make up GPCR family C. Currently available data suggest that family C GPCRs share a number of structural, biochemical and regulatory characteristics, which differ markedly from those of the other GPCR families, most notably the rhodopsin/family A GPCRs that have been most widely studied to date. This review will focus on the group I mGlu receptors (mGlu1 and mGlu5). This subgroup of receptors is widely and differentially expressed in neuronal and glial cells within the brain, and receptor activation has been implicated in the control of an array of key signalling events, including roles in the adaptative changes needed for long-term depression or potentiation of neuronal synaptic connectivity. In addition to playing critical physiological roles within the brain, the mGlu receptors are also currently the focus of considerable attention because of their potential as drug targets for the treatment of a variety of neurological and psychiatric disorders. PMID:11672421

  17. A new family of cytokinin receptors from Cereales.

    PubMed

    Kulaeva, O N; Zagranichnaya, T K; Brovko, F A; Karavaiko, N N; Selivankina, S Y; Zemlyachenko, Y V; Hall, M; Lipkin, V M; Boziev, K M

    1998-02-20

    The highly specific recognition of a natural cytokinin, trans-zeatin, by cytokinin-binding protein (CBP) of 67 kDa from barley leaves was detected with an assay developed on the basis of cytokinin competition in ELISA with anti-idiotype antibodies (raised against antibodies to zeatin) for complex formation with CBP. Monoclonal antibodies (mAbs) raised against 70 kDa CBP from etiolated maize seedlings cross-reacted with barley 67 kDa CBP and prevented barley CBP and trans-zeatin induced activation of transcription elongation directed by RNA polymerase I associated with barley chromatin. One mAb (Z-6) had an agonistic effect. Maize CBP replaced barley CBP in activation of RNA synthesis with cytokinin in the barley transcription system. Hence, a new family of cytokinin receptors with common functions and immunodeterminants including maize and barley CBPs was found.

  18. Biochemical characterization of the aba2 and aba3 mutants in Arabidopsis thaliana.

    PubMed

    Schwartz, S H; Léon-Kloosterziel, K M; Koornneef, M; Zeevaart, J A

    1997-05-01

    Abscisic acid (ABA)-deficient mutants in a variety of species have been identified by screening for precocious germination and a wilty phenotype. Mutants at two new loci, aba2 and aba3, have recently been isolated in Arabidopsis thaliana (L.) Hynh. (K.M. Léon-Kloosterziel, M. Alvarez-Gil, G.J. Ruijs, S.E. Jacobsen, N.E. Olszewski, S.H. Schwartz, J.A.D. Zeevaart, M. Koornneef [1996] Plant J 10: 655-661), and the biochemical characterization of these mutants is presented here. Protein extracts from aba2 and aba3 plants displayed a greatly reduced ability to convert xanthoxin to ABA relative to the wild type. The next putative intermediate in ABA synthesis, ABA-aldehyde, was efficiently converted to ABA by extracts from aba2 but not by extracts from aba3 plants. This indicates that the aba2 mutant is blocked in the conversion of xanthoxin to ABA-aldehyde and that aba3 is impaired in the conversion of ABA-aldehyde to ABA. Extracts from the aba3 mutant also lacked additional activities that require a molybdenum cofactor (Moco). Nitrate reductase utilizes a Moco but its activity was unaffected in extracts from aba3 plants. Moco hydroxylases in animals require a desulfo moiety of the cofactor. A sulfido ligand can be added to the Moco by treatment with Na2S and dithionite. Treatment of aba3 extracts with Na2S restored ABA-aldehyde oxidase activity. Therefore, the genetic lesion in aba3 appears to be in the introduction of S into the Moco. PMID:9159947

  19. Molecular basis for amino acid sensing by family C G-protein-coupled receptors

    PubMed Central

    Wellendorph, P; Bräuner-Osborne, H

    2009-01-01

    Family C of human G-protein-coupled receptors (GPCRs) is constituted by eight metabotropic glutamate receptors, two γ-aminobutyric acid type B (GABAB1–2) subunits forming the heterodimeric GABAB receptor, the calcium-sensing receptor, three taste1 receptors (T1R1–3), a promiscuous L-α-amino acid receptor G-protein-coupled receptor family C, group 6, subtype A (GPRC6A) and seven orphan receptors. Aside from the orphan receptors, the family C GPCRs are dimeric receptors characterized by a large extracellular Venus flytrap domain which bind the endogenous agonists. Except from the GABAB1–2 and T1R2–3 receptor, all receptors are either activated or positively modulated by amino acids. In this review, we outline mutational, biophysical and structural studies which have elucidated the interaction of the amino acids with the Venus flytrap domains, molecular mechanisms of receptor selectivity and the initial steps in receptor activation. PMID:19298394

  20. The Citrus ABA signalosome: identification and transcriptional regulation during sweet orange fruit ripening and leaf dehydration

    PubMed Central

    Rodrigo, María J.

    2012-01-01

    The abscisic acid (ABA) signalling core in plants include the cytosolic ABA receptors (PYR/PYL/RCARs), the clade-A type 2C protein phosphatases (PP2CAs), and the subclass III SNF1-related protein kinases 2 (SnRK2s). The aim of this work was to identify these ABA perception system components in sweet orange and to determine the influence of endogenous ABA on their transcriptional regulation during fruit development and ripening, taking advantage of the comparative analysis between a wild-type and a fruit-specific ABA-deficient mutant. Transcriptional changes in the ABA signalosome during leaf dehydration were also studied. Six PYR/PYL/RCAR, five PP2CA, and two subclass III SnRK2 genes, homologous to those of Arabidopsis, were identified in the Citrus genome. The high degree of homology and conserved motifs for protein folding and for functional activity suggested that these Citrus proteins are bona fide core elements of ABA perception in orange. Opposite expression patterns of CsPYL4 and CsPYL5 and ABA accumulation were found during ripening, although there were few differences between varieties. In contrast, changes in expression of CsPP2CA genes during ripening paralleled those of ABA content and agreeed with the relevant differences between wild-type and mutant fruit transcript accumulation. CsSnRK2 gene expression continuously decreased with ripening and no remarkable differences were found between cultivars. Overall, dehydration had a minor effect on CsPYR/PYL/RCAR and CsSnRK2 expression in vegetative tissue, whereas CsABI1, CsAHG1, and CsAHG3 were highly induced by water stress. The global results suggest that responsiveness to ABA changes during citrus fruit ripening, and leaf dehydration was higher in the CsPP2CA gene negative regulators than in the other ABA signalosome components. PMID:22888124

  1. The Citrus ABA signalosome: identification and transcriptional regulation during sweet orange fruit ripening and leaf dehydration.

    PubMed

    Romero, Paco; Lafuente, María T; Rodrigo, María J

    2012-08-01

    The abscisic acid (ABA) signalling core in plants include the cytosolic ABA receptors (PYR/PYL/RCARs), the clade-A type 2C protein phosphatases (PP2CAs), and the subclass III SNF1-related protein kinases 2 (SnRK2s). The aim of this work was to identify these ABA perception system components in sweet orange and to determine the influence of endogenous ABA on their transcriptional regulation during fruit development and ripening, taking advantage of the comparative analysis between a wild-type and a fruit-specific ABA-deficient mutant. Transcriptional changes in the ABA signalosome during leaf dehydration were also studied. Six PYR/PYL/RCAR, five PP2CA, and two subclass III SnRK2 genes, homologous to those of Arabidopsis, were identified in the Citrus genome. The high degree of homology and conserved motifs for protein folding and for functional activity suggested that these Citrus proteins are bona fide core elements of ABA perception in orange. Opposite expression patterns of CsPYL4 and CsPYL5 and ABA accumulation were found during ripening, although there were few differences between varieties. In contrast, changes in expression of CsPP2CA genes during ripening paralleled those of ABA content and agreeed with the relevant differences between wild-type and mutant fruit transcript accumulation. CsSnRK2 gene expression continuously decreased with ripening and no remarkable differences were found between cultivars. Overall, dehydration had a minor effect on CsPYR/PYL/RCAR and CsSnRK2 expression in vegetative tissue, whereas CsABI1, CsAHG1, and CsAHG3 were highly induced by water stress. The global results suggest that responsiveness to ABA changes during citrus fruit ripening, and leaf dehydration was higher in the CsPP2CA gene negative regulators than in the other ABA signalosome components. PMID:22888124

  2. Characterization of Aryl Hydrocarbon Receptor Interacting Protein (AIP) Mutations in Familial Isolated Pituitary Adenoma Families

    PubMed Central

    Igreja, Susana; Chahal, Harvinder S; King, Peter; Bolger, Graeme B; Srirangalingam, Umasuthan; Guasti, Leonardo; Chapple, J Paul; Trivellin, Giampaolo; Gueorguiev, Maria; Guegan, Katie; Stals, Karen; Khoo, Bernard; Kumar, Ajith V; Ellard, Sian; Grossman, Ashley B; Korbonits, Márta

    2010-01-01

    Familial isolated pituitary adenoma (FIPA) is an autosomal dominant condition with variable genetic background and incomplete penetrance. Germline mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene have been reported in 15–40% of FIPA patients. Limited data are available on the functional consequences of the mutations or regarding the regulation of the AIP gene. We describe a large cohort of FIPA families and characterize missense and silent mutations using minigene constructs, luciferase and β-galactosidase assays, as well as in silico predictions. Patients with AIP mutations had a lower mean age at diagnosis (23.6±11.2 years) than AIP mutation-negative patients (40.4±14.5 years). A promoter mutation showed reduced in vitro activity corresponding to lower mRNA expression in patient samples. Stimulation of the protein kinase A-pathway positively regulates the AIP promoter. Silent mutations led to abnormal splicing resulting in truncated protein or reduced AIP expression. A two-hybrid assay of protein–protein interaction of all missense variants showed variable disruption of AIP-phosphodiesterase-4A5 binding. In summary, exonic, promoter, splice-site, and large deletion mutations in AIP are implicated in 31% of families in our FIPA cohort. Functional characterization of AIP changes is important to identify the functional impact of gene sequence variants. Hum Mutat 31:1–11, 2010. © 2010 Wiley-Liss, Inc. PMID:20506337

  3. ABA-alcohol is an intermediate in abscisic acid biosynthesis

    SciTech Connect

    Rock, C.D.; Zeevaart, J.A.D. )

    1990-05-01

    It has been established that ABA-aldehyde is a precursor to ABA. The ABA-deficient flacca and sitiens mutants of tomato are blocked in the conversion of ABA-aldehyde to ABA, and accumulate trans-ABA-alcohol. {sup 18}O-Labeling studies of ABA in flacca and sitiens show that these mutants synthesize a large percentage of ({sup 18}O)ABA which contains two {sup 18}O atoms in the carboxyl group. Furthermore, the mutants synthesize much greater amounts of trans-ABA-glucose ester (t-ABA-GE) compared with the wild type, and this ({sup 18}O)t-ABA-GE is also double labeled in the carboxyl group. Our interpretation of these data is that the {sup 18}O in ABA-aldehyde is trapped in the side chain by reduction to ({sup 18}O)ABA-alcohol, followed by isomerization to ({sup 18}O)t-ABA-alcohol and oxidation with {sup 18}O{sub 2} to ({sup 18}O)t-ABA. The ({sup 18}O)t-ABA is then rapidly converted to ({sup 18}O)t-ABA-GE. Because ({sup 18}O)ABA doubly labeled in the carboxyl group has been observed in small amounts in labeling experiments with several species, and various species have been shown to convert ABA-aldehyde to ABA-alcohol and t-ABA-alcohol, we propose that ABA-alcohol is an ABA intermediate in a shunt pathway.

  4. Evolution of an Expanded Mannose Receptor Gene Family

    PubMed Central

    Staines, Karen; Hunt, Lawrence G.; Young, John R.; Butter, Colin

    2014-01-01

    Sequences of peptides from a protein specifically immunoprecipitated by an antibody, KUL01, that recognises chicken macrophages, identified a homologue of the mammalian mannose receptor, MRC1, which we called MRC1L-B. Inspection of the genomic environment of the chicken gene revealed an array of five paralogous genes, MRC1L-A to MRC1L-E, located between conserved flanking genes found either side of the single MRC1 gene in mammals. Transcripts of all five genes were detected in RNA from a macrophage cell line and other RNAs, whose sequences allowed the precise definition of spliced exons, confirming or correcting existing bioinformatic annotation. The confirmed gene structures were used to locate orthologues of all five genes in the genomes of two other avian species and of the painted turtle, all with intact coding sequences. The lizard genome had only three genes, one orthologue of MRC1L-A and two orthologues of the MRC1L-B antigen gene resulting from a recent duplication. The Xenopus genome, like that of most mammals, had only a single MRC1-like gene at the corresponding locus. MRC1L-A and MRC1L-B genes had similar cytoplasmic regions that may be indicative of similar subcellular migration and functions. Cytoplasmic regions of the other three genes were very divergent, possibly indicating the evolution of a new functional repertoire for this family of molecules, which might include novel interactions with pathogens. PMID:25390371

  5. Familial polycythemia due to truncations of the erythropoietin receptor.

    PubMed Central

    Forget, B. G.; Degan, B. A.; Arcasoy, M. O.

    2000-01-01

    We studied a kindred with dominantly inherited familial erythrocytosis associated with heterozygosity for a deletion of seven nucleotides in exon 8 of the EpoR gene resulting in an EpoR peptide that is truncated by 59 amino acids in its C-terminal intracytoplasmic signal transduction domain. A seven basepair direct repeat sequence is present in the normal EpoR gene at the site of this mutation, consistent with the slipped mispairing model for the generation of short deletions during DNA replication. Hypersensitivity to erythropoietin of primary erythroid progenitors from an affected individual was observed in in vitro cultures of peripheral blood mononuclear cells, as indicated by the growth, at suboptimal concentrations of added Epo, of more numerous and larger BFU-E-derived erythroid cell colonies compared to those obtained from a normal control subject. To study mutant EpoR function, the cDNA encoding the mutant EpoR was stably transfected into murine growth factor (IL-3)-dependent 32D tissue culture cells. In proliferation assays, cells expressing the mutant EpoR displayed 5 to 10-fold increased sensitivity to Epo compared to cells expressing similar numbers of the wild type EpoR. In addition, the cells transfected with the mutant truncated receptor demonstrated prolonged activity of Jak2 kinase and Stat5 activity, molecules that mediate signal transduction by the EpoR. PMID:10881330

  6. ABA-induced CCCH tandem zinc finger protein OsC3H47 decreases ABA sensitivity and promotes drought tolerance in Oryza sativa.

    PubMed

    Wang, Wenyi; Liu, Bohan; Xu, Mengyun; Jamil, Muhammad; Wang, Guoping

    2015-08-14

    Water deficit causes multiple negative impacts on plants, such as reactive oxygen species (ROS) accumulation, abscisic acid (ABA) induction, stomatal closure, and decreased photosynthesis. Here, we characterized OsC3H47, which belongs to CCCH zinc-finger families, as a drought-stress response gene. It can be strongly induced by NaCl, PEG, ABA, and drought conditions. Overexpression of OsC3H47 significantly enhanced tolerance to drought and salt stresses in rice seedlings, which indicates that OsC3H47 plays important roles in post-stress recovery. However, overexpression of OsC3H47 reduced the ABA sensitivity of rice seedlings. This suggests that OsC3H47 is a newly discovered gene that can control rice drought-stress response, and it may play an important role in ABA feedback and post-transcription processes. PMID:26047696

  7. A nonsense mutation in the LDL receptor gene leads to familial hypercholesterolemia in the Druze sect

    SciTech Connect

    Landsberger, D.; Meiner, V.; Reshef, A.; Leitersdorf, E. ); Levy, Yishai ); Westhytzen, D.R. van der; Coetzee, G.A. )

    1992-02-01

    Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the LDL receptor gene. Here the authors characterize and LDL receptor mutation that is associated with a distinct haplotype and causes FH in the Druze, a small Middle Eastern Islamic sect with a high degree of inbreeding. The mutation was found in FH families from two distinct Druze villages from the Golan Heights (northern Israel). It was not found either in another Druze FH family residing in a different geographical area nor in eight Arab and four Jewish FH heterozygote index cases whose hypercholesterolemia cosegregates with an identical LDL receptor gene haplotype. The mutation, a single-base substitution, results in a termination codon in exon 4 of the LDL receptor gene that encodes for the fourth repeat of the binding domain of the mature receptor. It can be diagnosed by allele-specific oligonucleotide hybridization of PCR-amplified DNA from FH patients.

  8. Cloning and localization of two multigene receptor families in goldfish olfactory epithelium

    PubMed Central

    Cao, Yanxiang; Oh, Bryan C.; Stryer, Lubert

    1998-01-01

    Goldfish reproduction is coordinated by pheromones that are released by ovulating females and detected by males. Two highly potent pheromones, a dihydroxyprogesterone and a prostaglandin, previously have been identified, and their effects on goldfish behavior have been studied in depth. We have cloned goldfish olfactory epithelium cDNAs belonging to two multigene G-protein coupled receptor families as a step toward elucidating the molecular basis of pheromone recognition. One gene family (GFA) consists of homologs of putative odorant receptors (≈320 residues) found in the olfactory epithelium of other fish and mammals. The other family (GFB) consists of homologs of putative pheromone receptors found in the vomeronasal organ (VNO) of mammals and also in the nose of pufferfish. GFB receptors (≈840 residues) are akin to the V2R family of VNO receptors, which possess a large extracellular N-terminal domain and are homologs of calcium-sensing and metabotropic glutamate receptors. In situ hybridization showed that the two families of goldfish receptors are differentially expressed in the olfactory epithelium. GFB mRNA is abundant in rather compact cells whose nuclei are near the apical surface. In contrast, GFA mRNA is found in elongated cells whose nuclei are positioned deeper in the epithelium. Our findings support the hypothesis that the separate olfactory organ and VNO of terrestrial vertebrates arose in evolution by the segregation of distinct classes of neurons that were differentially positioned in the olfactory epithelium of a precursor aquatic vertebrate. PMID:9751777

  9. Discovery of a novel member of the histamine receptor family.

    PubMed

    Nguyen, T; Shapiro, D A; George, S R; Setola, V; Lee, D K; Cheng, R; Rauser, L; Lee, S P; Lynch, K R; Roth, B L; O'Dowd, B F

    2001-03-01

    We report the discovery, tissue distribution and pharmacological characterization of a novel receptor, which we have named H4. Like the three histamine receptors reported previously (H1, H2, and H3), the H4 receptor is a G protein-coupled receptor and is most closely related to the H3 receptor, sharing 58% identity in the transmembrane regions. The gene encoding the H4 receptor was discovered initially in a search of the GenBank databases as sequence fragments retrieved in a partially sequenced human genomic contig mapped to chromosome 18. These sequences were used to retrieve a partial cDNA clone and, in combination with genomic fragments, were used to determine the full-length open reading frame of 390 amino acids. Northern analysis revealed a 3.0-kb transcript in rat testis and intestine. Radioligand binding studies indicated that the H4 receptor has a unique pharmacology and binds [(3)H]histamine (K(d) = 44 nM) and [(3)H]pyrilamine (K(d) = 32 nM) and several psychoactive compounds (amitriptyline, chlorpromazine, cyproheptadine, mianserin) with moderate affinity (K(i) range of 33-750 nM). Additionally, histamine induced a rapid internalization of HA-tagged H4 receptors in transfected human embryonic kidney 293 cells.

  10. Leveraging abscisic acid receptors for efficient water use in Arabidopsis.

    PubMed

    Yang, Zhenyu; Liu, Jinghui; Tischer, Stefanie V; Christmann, Alexander; Windisch, Wilhelm; Schnyder, Hans; Grill, Erwin

    2016-06-14

    Plant growth requires the influx of atmospheric CO2 through stomatal pores, and this carbon uptake for photosynthesis is inherently associated with a large efflux of water vapor. Under water deficit, plants reduce transpiration and are able to improve carbon for water exchange leading to higher water use efficiency (WUE). Whether increased WUE can be achieved without trade-offs in plant growth is debated. The signals mediating the WUE response under water deficit are not fully elucidated but involve the phytohormone abscisic acid (ABA). ABA is perceived by a family of related receptors known to mediate acclimation responses and to reduce transpiration. We now show that enhanced stimulation of ABA signaling via distinct ABA receptors can result in plants constitutively growing at high WUE in the model species Arabidopsis WUE was assessed by three independent approaches involving gravimetric analyses, (13)C discrimination studies of shoots and derived cellulose fractions, and by gas exchange measurements of whole plants and individual leaves. Plants expressing the ABA receptors RCAR6/PYL12 combined up to 40% increased WUE with high growth rates, i.e., are water productive. Water productivity was associated with maintenance of net carbon assimilation by compensatory increases of leaf CO2 gradients, thereby sustaining biomass acquisition. Leaf surface temperatures and growth potentials of plants growing under well-watered conditions were found to be reliable indicators for water productivity. The study shows that ABA receptors can be explored to generate more plant biomass per water transpired, which is a prime goal for a more sustainable water use in agriculture. PMID:27247417

  11. Leveraging abscisic acid receptors for efficient water use in Arabidopsis

    PubMed Central

    Yang, Zhenyu; Liu, Jinghui; Tischer, Stefanie V.; Christmann, Alexander; Windisch, Wilhelm; Schnyder, Hans; Grill, Erwin

    2016-01-01

    Plant growth requires the influx of atmospheric CO2 through stomatal pores, and this carbon uptake for photosynthesis is inherently associated with a large efflux of water vapor. Under water deficit, plants reduce transpiration and are able to improve carbon for water exchange leading to higher water use efficiency (WUE). Whether increased WUE can be achieved without trade-offs in plant growth is debated. The signals mediating the WUE response under water deficit are not fully elucidated but involve the phytohormone abscisic acid (ABA). ABA is perceived by a family of related receptors known to mediate acclimation responses and to reduce transpiration. We now show that enhanced stimulation of ABA signaling via distinct ABA receptors can result in plants constitutively growing at high WUE in the model species Arabidopsis. WUE was assessed by three independent approaches involving gravimetric analyses, 13C discrimination studies of shoots and derived cellulose fractions, and by gas exchange measurements of whole plants and individual leaves. Plants expressing the ABA receptors RCAR6/PYL12 combined up to 40% increased WUE with high growth rates, i.e., are water productive. Water productivity was associated with maintenance of net carbon assimilation by compensatory increases of leaf CO2 gradients, thereby sustaining biomass acquisition. Leaf surface temperatures and growth potentials of plants growing under well-watered conditions were found to be reliable indicators for water productivity. The study shows that ABA receptors can be explored to generate more plant biomass per water transpired, which is a prime goal for a more sustainable water use in agriculture. PMID:27247417

  12. Theoretical and Computational Studies of Peptides and Receptors of the Insulin Family

    PubMed Central

    Vashisth, Harish

    2015-01-01

    Synergistic interactions among peptides and receptors of the insulin family are required for glucose homeostasis, normal cellular growth and development, proliferation, differentiation and other metabolic processes. The peptides of the insulin family are disulfide-linked single or dual-chain proteins, while receptors are ligand-activated transmembrane glycoproteins of the receptor tyrosine kinase (RTK) superfamily. Binding of ligands to the extracellular domains of receptors is known to initiate signaling via activation of intracellular kinase domains. While the structure of insulin has been known since 1969, recent decades have seen remarkable progress on the structural biology of apo and liganded receptor fragments. Here, we review how this useful structural information (on ligands and receptors) has enabled large-scale atomically-resolved simulations to elucidate the conformational dynamics of these biomolecules. Particularly, applications of molecular dynamics (MD) and Monte Carlo (MC) simulation methods are discussed in various contexts, including studies of isolated ligands, apo-receptors, ligand/receptor complexes and intracellular kinase domains. The review concludes with a brief overview and future outlook for modeling and computational studies in this family of proteins. PMID:25680077

  13. Chemical and biological profiling of an annotated compound library directed to the nuclear receptor family.

    PubMed

    Cases, Montserrat; García-Serna, Ricard; Hettne, Kristina; Weeber, Marc; van der Lei, Johan; Boyer, Scott; Mestres, Jordi

    2005-01-01

    Nuclear receptors form a family of ligand-activated transcription factors that regulate a wide variety of biological processes and are thus generally considered relevant targets in drug discovery. We have constructed an annotated compound library directed to nuclear receptors (NRacl) as a means for integrating the chemical and biological data being generated within this family. Special care has been put in the appropriate storage of annotations by using hierarchical classification schemes for both molecules and nuclear receptors, which takes the ability to extract knowledge from annotated compound libraries to another level. Analysis of NRacl has ultimately led to the identification of scaffolds with highly promiscuous nuclear receptor profiles and to the classification of nuclear receptor groups with similar scaffold promiscuity patterns. This information can be exploited in the design of probing libraries for deorphanization activities as well as for devising screening batteries to address selectivity issues.

  14. The βc receptor family - Structural insights and their functional implications.

    PubMed

    Broughton, Sophie E; Nero, Tracy L; Dhagat, Urmi; Kan, Winnie L; Hercus, Timothy R; Tvorogov, Denis; Lopez, Angel F; Parker, Michael W

    2015-08-01

    Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) and IL-5 are members of a small family of cytokines that share a beta receptor subunit (βc). These cytokines regulate the growth, differentiation, migration and effector function activities of many hematopoietic cells in bone marrow, blood and sites of inflammation. Excessive or aberrant signaling can result in chronic inflammatory conditions and myeloid leukemias. The crystal structures of the GM-CSF ternary complex, the IL-5 binary complex and the very recent IL-3 receptor alpha subunit build upon decades of structure-function studies, giving new insights into cytokine-receptor specificity and signal transduction. Selective modulation of receptor function is now a real possibility and the structures of the βc receptor family are being used to discover novel and disease-specific therapeutics. PMID:25982846

  15. Isolation of an additional member of the fibroblast growth factor receptor family, FGFR-3.

    PubMed Central

    Keegan, K; Johnson, D E; Williams, L T; Hayman, M J

    1991-01-01

    The fibroblast growth factors are a family of polypeptide growth factors involved in a variety of activities including mitogenesis, angiogenesis, and wound healing. Fibroblast growth factor receptors (FGFRs) have previously been identified in chicken, mouse, and human and have been shown to contain an extracellular domain with either two or three immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tyrosine kinase domain. We have isolated a human cDNA for another tyrosine kinase receptor that is highly homologous to the previously described FGFR. Expression of this receptor cDNA in COS cells directs the expression of a 125-kDa glycoprotein. We demonstrate that this cDNA encodes a biologically active receptor by showing that human acidic and basic fibroblast growth factors activate this receptor as measured by 45Ca2+ efflux assays. These data establish the existence of an additional member of the FGFR family that we have named FGFR-3. Images PMID:1847508

  16. Molecular Characterization of the Aphis gossypii Olfactory Receptor Gene Families

    PubMed Central

    Walker, William B.; Li, Jianhong; Wang, Guirong

    2014-01-01

    The cotton aphid, Aphis gossypii Glover, is a polyphagous pest that inflicts great damage to cotton yields worldwide. Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, our aim is to identify chemosensory receptors in the cotton aphid genome, as a means to uncover olfactory encoding of the polyphagous feeding habits as well as to aid the discovery of new targets for behavioral interference. We identified a total of 45 candidate ORs and 14 IRs in the cotton aphid genome. Among the candidate AgoORs, 9 are apparent pseudogenes, while 19 can be clustered with ORs from the pea aphid, forming 16 AgoOR/ApOR orthologous subgroups. Among the candidate IRs, we identified homologs of the two highly conserved co-receptors IR8a and IR25a; no AgoIR retain the complete glutamic acid binding domain, suggesting that putative AgoIRs bind different ligands. Our results provide the necessary information for functional characterization of the chemosensory receptors of A. gossypii, with potential for new or refined applications of semiochemicals-based control of this pest insect. PMID:24971460

  17. Molecular characterization of the Aphis gossypii olfactory receptor gene families.

    PubMed

    Cao, Depan; Liu, Yang; Walker, William B; Li, Jianhong; Wang, Guirong

    2014-01-01

    The cotton aphid, Aphis gossypii Glover, is a polyphagous pest that inflicts great damage to cotton yields worldwide. Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, our aim is to identify chemosensory receptors in the cotton aphid genome, as a means to uncover olfactory encoding of the polyphagous feeding habits as well as to aid the discovery of new targets for behavioral interference. We identified a total of 45 candidate ORs and 14 IRs in the cotton aphid genome. Among the candidate AgoORs, 9 are apparent pseudogenes, while 19 can be clustered with ORs from the pea aphid, forming 16 AgoOR/ApOR orthologous subgroups. Among the candidate IRs, we identified homologs of the two highly conserved co-receptors IR8a and IR25a; no AgoIR retain the complete glutamic acid binding domain, suggesting that putative AgoIRs bind different ligands. Our results provide the necessary information for functional characterization of the chemosensory receptors of A. gossypii, with potential for new or refined applications of semiochemicals-based control of this pest insect. PMID:24971460

  18. Molecular evolution of a chordate specific family of G protein-coupled receptors

    PubMed Central

    2011-01-01

    Background Chordate evolution is a history of innovations that is marked by physical and behavioral specializations, which led to the development of a variety of forms from a single ancestral group. Among other important characteristics, vertebrates obtained a well developed brain, anterior sensory structures, a closed circulatory system and gills or lungs as blood oxygenation systems. The duplication of pre-existing genes had profound evolutionary implications for the developmental complexity in vertebrates, since mutations modifying the function of a duplicated protein can lead to novel functions, improving the evolutionary success. Results We analyzed here the evolution of the GPRC5 family of G protein-coupled receptors by comprehensive similarity searches and found that the receptors are only present in chordates and that the size of the receptor family expanded, likely due to genome duplication events in the early history of vertebrate evolution. We propose that a single GPRC5 receptor coding gene originated in a stem chordate ancestor and gave rise by duplication events to a gene family comprising three receptor types (GPRC5A-C) in vertebrates, and a fourth homologue present only in mammals (GPRC5D). Additional duplications of GPRC5B and GPRC5C sequences occurred in teleost fishes. The finding that the expression patterns of the receptors are evolutionarily conserved indicates an important biological function of these receptors. Moreover, we found that expression of GPRC5B is regulated by vitamin A in vivo, confirming previous findings that linked receptor expression to retinoic acid levels in tumor cell lines and strengthening the link between the receptor expression and the development of a complex nervous system in chordates, known to be dependent on retinoic acid signaling. Conclusions GPRC5 receptors, a class of G protein-coupled receptors with unique sequence characteristics, may represent a molecular novelty that helped non-chordates to become

  19. Role of abscisic acid (ABA) and Arabidopsis thaliana ABA-insensitive loci in low water potential-induced ABA and proline accumulation.

    PubMed

    Verslues, Paul E; Bray, Elizabeth A

    2006-01-01

    The mechanisms by which plants respond to reduced water availability (low water potential) include both ABA-dependent and ABA-independent processes. Pro accumulation and osmotic adjustment are two important traits for which the mechanisms of regulation by low water potential, and the involvement of ABA, is not well understood. The ABA-deficient mutant, aba2-1, was used to investigate the regulatory role of ABA in low water potential-induced Pro accumulation and osmotic adjustment in seedlings of Arabidopsis thaliana. Low water potential-induced Pro accumulation required wild-type levels of ABA, as well as a change in ABA sensitivity or ABA-independent events. Osmotic adjustment, in contrast, occurred independently of ABA accumulation in aba2-1. Quantification of low water potential-induced ABA and Pro accumulation in five ABA-insensitive mutants, abi1-1, abi2-1, abi3, abi4, and abi5, revealed that abi4 had increased Pro accumulation at low water potential, but a reduced response to exogenous ABA. Both of these responses were modified by sucrose treatment, indicating that ABI4 has a role in connecting ABA and sugar in regulating Pro accumulation. Of the other abi mutants, only abi1 had reduced Pro accumulation in response to low water potential and ABA application. It was also observed that abi1-1 and abi2-1 had increased ABA accumulation. The involvement of these loci in feedback regulation of ABA accumulation may occur through an effect on ABA catabolism or conjugation. These data provide new information on the function of ABA in seedlings exposed to low water potential and define new roles for three of the well-studied abi loci.

  20. International Union of Basic and Clinical Pharmacology. XCIII. The parathyroid hormone receptors--family B G protein-coupled receptors.

    PubMed

    Gardella, Thomas J; Vilardaga, Jean-Pierre

    2015-01-01

    The type-1 parathyroid hormone receptor (PTHR1) is a family B G protein-coupled receptor (GPCR) that mediates the actions of two polypeptide ligands; parathyroid hormone (PTH), an endocrine hormone that regulates the levels of calcium and inorganic phosphate in the blood by acting on bone and kidney, and PTH-related protein (PTHrP), a paracrine-factor that regulates cell differentiation and proliferation programs in developing bone and other tissues. The type-2 parathyroid hormone receptor (PTHR2) binds a peptide ligand, called tuberoinfundibular peptide-39 (TIP39), and while the biologic role of the PTHR2/TIP39 system is not as defined as that of the PTHR1, it likely plays a role in the central nervous system as well as in spermatogenesis. Mechanisms of action at these receptors have been explored through a variety of pharmacological and biochemical approaches, and the data obtained support a basic "two-site" mode of ligand binding now thought to be used by each of the family B peptide hormone GPCRs. Recent crystallographic studies on the family B GPCRs are providing new insights that help to further refine the specifics of the overall receptor architecture and modes of ligand docking. One intriguing pharmacological finding for the PTHR1 is that it can form surprisingly stable complexes with certain PTH/PTHrP ligand analogs and thereby mediate markedly prolonged cell signaling responses that persist even when the bulk of the complexes are found in internalized vesicles. The PTHR1 thus appears to be able to activate the Gα(s)/cAMP pathway not only from the plasma membrane but also from the endosomal domain. The cumulative findings could have an impact on efforts to develop new drug therapies for the PTH receptors.

  1. Systematic biochemical characterization of the SAM domains in Eph receptor family from Mus Musculus.

    PubMed

    Wang, Yue; Li, Qingxia; Zheng, Yunhua; Li, Gang; Liu, Wei

    2016-05-13

    The Eph receptor family is the largest subfamily of receptor tyrosine kinases and well-known for their pivotal roles in axon guidance, synaptogenesis, artery/venous differentiation and tumorigenesis, etc. Activation of the Eph receptor needs multimerization of the receptors. The intracellular C-terminal SAM domain of Eph receptor was reported to mediate self-association of Eph receptors via the homo SAM-SAM interaction. In this study, we systematically expressed and purified the SAM domain proteins of all fourteen Eph receptors of Mus musculus in Escherichia coli. The FPLC (fast protein liquid chromatography) results showed the recombinant SAM domains were highly homogeneous. Using CD (circular dichroism) spectrometry, we found that the secondary structure of all the SAM domains was typically alpha helical folded and remarkably similar. The thermo-stability tests showed that they were quite stable in solution. SEC-MALS (size exclusion chromatography coupled with multiple angle light scattering) results illustrated 200 μM Eph SAM domains behaved as good monomers in the size-exclusion chromatography. More importantly, DLS (dynamic light scattering) results revealed the overwhelming majority of SAM domains was not multimerized in solution either at 200 μM or 2000 μM protein concentration, which indicating the SAM domain alone was not sufficient to mediate the polymerization of Eph receptor. In summary, our studies provided the systematic biochemical characterizations of the Eph receptor SAM domains and implied their roles in Eph receptor mediated signaling pathways. PMID:27086853

  2. The Under-Appreciated Promiscuity of the Epidermal Growth Factor Receptor Family

    PubMed Central

    Kennedy, Sean P.; Hastings, Jordan F.; Han, Jeremy Z. R.; Croucher, David R.

    2016-01-01

    Each member of the epidermal growth factor receptor (EGFR) family plays a key role in normal development, homeostasis, and a variety of pathophysiological conditions, most notably in cancer. According to the prevailing dogma, these four receptor tyrosine kinases (RTKs; EGFR, ERBB2, ERBB3, and ERBB4) function exclusively through the formation of homodimers and heterodimers within the EGFR family. These combinatorial receptor interactions are known to generate increased interactome diversity and therefore influence signaling output, subcellular localization and function of the heterodimer. This molecular plasticity is also thought to play a role in the development of resistance toward targeted cancer therapies aimed at these known oncogenes. Interestingly, many studies now challenge this dogma and suggest that the potential for EGFR family receptors to interact with more distantly related RTKs is much greater than currently appreciated. Here we discuss how the promiscuity of these oncogenic receptors may lead to the formation of many unexpected receptor pairings and the significant implications for the efficiency of many targeted cancer therapies.

  3. The Under-Appreciated Promiscuity of the Epidermal Growth Factor Receptor Family.

    PubMed

    Kennedy, Sean P; Hastings, Jordan F; Han, Jeremy Z R; Croucher, David R

    2016-01-01

    Each member of the epidermal growth factor receptor (EGFR) family plays a key role in normal development, homeostasis, and a variety of pathophysiological conditions, most notably in cancer. According to the prevailing dogma, these four receptor tyrosine kinases (RTKs; EGFR, ERBB2, ERBB3, and ERBB4) function exclusively through the formation of homodimers and heterodimers within the EGFR family. These combinatorial receptor interactions are known to generate increased interactome diversity and therefore influence signaling output, subcellular localization and function of the heterodimer. This molecular plasticity is also thought to play a role in the development of resistance toward targeted cancer therapies aimed at these known oncogenes. Interestingly, many studies now challenge this dogma and suggest that the potential for EGFR family receptors to interact with more distantly related RTKs is much greater than currently appreciated. Here we discuss how the promiscuity of these oncogenic receptors may lead to the formation of many unexpected receptor pairings and the significant implications for the efficiency of many targeted cancer therapies. PMID:27597943

  4. The Under-Appreciated Promiscuity of the Epidermal Growth Factor Receptor Family

    PubMed Central

    Kennedy, Sean P.; Hastings, Jordan F.; Han, Jeremy Z. R.; Croucher, David R.

    2016-01-01

    Each member of the epidermal growth factor receptor (EGFR) family plays a key role in normal development, homeostasis, and a variety of pathophysiological conditions, most notably in cancer. According to the prevailing dogma, these four receptor tyrosine kinases (RTKs; EGFR, ERBB2, ERBB3, and ERBB4) function exclusively through the formation of homodimers and heterodimers within the EGFR family. These combinatorial receptor interactions are known to generate increased interactome diversity and therefore influence signaling output, subcellular localization and function of the heterodimer. This molecular plasticity is also thought to play a role in the development of resistance toward targeted cancer therapies aimed at these known oncogenes. Interestingly, many studies now challenge this dogma and suggest that the potential for EGFR family receptors to interact with more distantly related RTKs is much greater than currently appreciated. Here we discuss how the promiscuity of these oncogenic receptors may lead to the formation of many unexpected receptor pairings and the significant implications for the efficiency of many targeted cancer therapies. PMID:27597943

  5. Non-canonical signaling mode of the epidermal growth factor receptor family

    PubMed Central

    Lee, Heng-Huan; Wang, Ying-Nai; Hung, Mien-Chie

    2015-01-01

    Epidermal growth factor receptor (EGFR) and its family members are key players in both physiological and pathological settings for which they are well recognized as models for investigating the functions and regulations of other membrane receptor tyrosine kinases (RTKs) and serve as therapeutic targets critical to clinical need and fundamental research. The canonical view of the pivotal functions in the EGFR family has been well documented as being an initiator of signaling amplification cascades from the plasma membrane to different subcellular compartments via receptor endocytic trafficking, intermolecular interaction, and kinase-substrate reaction in a temporalspatial manner. However, several lines of evidence have identified non-canonical roles of the EGFR family, acting as a transcriptional factor and a chromatin regulator in the nucleus to regulate gene expression, DNA replication, and DNA damage repair. Moreover, the EGFR family can even exert its impact outside the host cell through exosomal vesicle secretion. The emerging concept of the non-canonical roles of the EGFR family reveals an astonishing and elaborate scheme on the molecular functions of membrane RTKs, offering new insights into the receptor biology as well as the development of comprehensive therapeutic strategies in the future. PMID:26693051

  6. Exploring the Evolutionary Relationship of Insulin Receptor Substrate Family Using Computational Biology

    PubMed Central

    Chakraborty, Chiranjib; Agoramoorthy, Govindasamy; Hsu, Minna J.

    2011-01-01

    Insulin receptor substrate (IRS) harbors proteins such as IRS1, IRS2, IRS3, IRS4, IRS5 and IRS6. These key proteins act as vital downstream regulators in the insulin signaling pathway. However, little is known about the evolutionary relationship among the IRS family members. This study explores the potential to depict the evolutionary relationship among the IRS family using bioinformatics, algorithm analysis and mathematical models. PMID:21364910

  7. Mouse T-cell receptor variable gene segment families

    SciTech Connect

    Arden, B.; Kabelitz, D.; Clark, S.P.; Mak, T.W.

    1995-10-01

    All mouse T-cell receptor {alpha}/{delta}, {beta}, and {gamma} variable (Tcra/d-, b-, and g-V) gene segments were aligned to compare the sequences with one another, to group them into subfamilies, and to derive a name which complies with the standard nomenclature. it was necessary to change the names of some V gene segments because they conflicted with those of other segments. The traditional classification into subfamilies was re-evaluated using a much larger pool of sequences. In the mouse, most V gene segments can be grouped into subfamilies of closely related genes with significantly less similarity between different subfamilies. 118 refs., 11 figs., 4 tabs.

  8. Neuropeptide Y family receptors Y1 and Y2 from sea lamprey, Petromyzon marinus.

    PubMed

    Xu, Bo; Lagman, David; Sundström, Görel; Larhammar, Dan

    2015-10-01

    The vertebrate gene family for neuropeptide Y (NPY) receptors expanded by duplication of the chromosome carrying the ancestral Y1-Y2-Y5 gene triplet. After loss of some duplicates, the ancestral jawed vertebrate had seven receptor subtypes forming the Y1 (including Y1, Y4, Y6, Y8), Y2 (including Y2, Y7) and Y5 (only Y5) subfamilies. Lampreys are considered to have experienced the same chromosome duplications as gnathostomes and should also be expected to have multiple receptor genes. However, previously only a Y4-like and a Y5 receptor have been cloned and characterized. Here we report the cloning and characterization of two additional receptors from the sea lamprey Petromyzon marinus. Sequence phylogeny alone could not with certainty assign their identity, but based on synteny comparisons of P. marinus and the Arctic lamprey, Lethenteron camtschaticum, with jawed vertebrates, the two receptors most likely are Y1 and Y2. Both receptors were expressed in human HEK293 cells and inositol phosphate assays were performed to determine the response to the three native lamprey peptides NPY, PYY and PMY. The three peptides have similar potencies in the nanomolar range for Y1. No obvious response to the three peptides was detected for Y2. Synteny analysis supports identification of the previously cloned receptor as Y4. No additional NPY receptor genes could be identified in the presently available lamprey genome assemblies. Thus, four NPY-family receptors have been identified in lampreys, orthologs of the same subtypes as in humans (Y1, Y2, Y4 and Y5), whereas many other vertebrate lineages have retained additional ancestral subtypes.

  9. Dynamic Evolution of Toll-Like Receptor Multigene Families in Echinoderms

    PubMed Central

    Buckley, Katherine M.; Rast, Jonathan P.

    2012-01-01

    The genome sequence of the purple sea urchin, Strongylocentrotus purpuratus, a large and long-lived invertebrate, provides a new perspective on animal immunity. Analysis of this genome uncovered a highly complex immune system in which the gene families that encode homologs of the pattern recognition receptors that form the core of vertebrate innate immunity are encoded in large multigene families. The sea urchin genome contains 253 Toll-like receptor (TLR) sequences, more than 200 Nod-like receptors and 1095 scavenger receptor cysteine-rich domains, a 10-fold expansion relative to vertebrates. Given their stereotypic protein structure and simple intron-exon architecture, the TLRs are the most tractable of these families for more detailed analysis. A role for these receptors in immune defense is suggested by their similarity to TLRs in other organisms, sequence diversity, and expression in immunologically active tissues, including phagocytes. The complexity of the sea urchin TLR multigene families is largely derived from expansions independent of those in vertebrates and protostomes, although a small family of TLRs with structure similar to that of Drosophila Toll can be traced to an ancient eumetazoan ancestor. Several other echinoderm sequences are now available, including Lytechinus variegatus, as well as partial sequences from two other sea urchin species. Here, we present an analysis of the invertebrate deuterostome TLRs with emphasis on the echinoderms. Representatives of most of the S. purpuratus TLR subfamilies and homologs of the mccTLR sequences are found in L. variegatus, although the L. variegatus TLR gene family is notably smaller (68 TLR sequences). The phylogeny of these genes within sea urchins highlights lineage-specific expansions at higher resolution than is evident at the phylum level. These analyses identify quickly evolving TLR subfamilies that are likely to have novel immune recognition functions and other, more stable, subfamilies that may

  10. A missense mutation in the Ca-sensing receptor gene causes familial autosomal dominant hypoparathyroidism

    SciTech Connect

    Perry, Y.M.; Finegold, D.N.; Armitage, M.M.

    1994-09-01

    A large family was identified in which hypoparathyroidism was observed to segregate as an autosomal dominant trait in 3 generations. Linkage analysis using short tandem repeat polymorphisms linked the disease phenotype to chromosomal region 3q13. This region contains a newly identified Ca-sensing receptor (PCAR1) gene. This receptor regulates the secretion of parathyroid hormone from parathyroid cells in response to extracellular ionized Ca concentration ([Ca{sup +2}]). PCR-based single stranded conformational analysis of exonic sequences of the PCAR1 gene revealed an abnormal conformer in exon 3 in affected individuals. Direct sequencing of the amplification product from an affected and an unaffected family member showed an A {yields} G transition at nucleotide 770 of the PCAR1 gene [numbering based on the bovine sequence (Genbank accession number S67307)]. This substitution created a Msp1 restriction site which cosegregated with hypoparathyroidism in this family. This substitution was not observed in unaffected family members, unrelated spouses, or unrelated population controls. This substitution is predicted to result in the replacement of a glutamine residue at amino acid 246 by an arginine residue. The Ca-sensing receptor appears to be a member of the family of seven membrane spanning G-protein linked receptors. The extracellular location of this amino acid substitution appears to produce a gain of function mutation increasing the receptor sensitivity to [Ca{sup +2}] and decreasing the calcium {open_quotes}set point{close_quotes}. This is in contrast to the loss of function mutations observed in the PCAR1 gene in pedigrees with familial hypercalcemic hypocalciuria.

  11. NTB-A Receptor Crystal Structure: Insights into Homophilic Interactions in the Signaling Lymphocytic Activation Molecule Receptor Family

    SciTech Connect

    Cao,E.; Ramagopal, U.; Fedorov, A.; Fedorov, E.; Yan, Q.; Lary, J.; Cole, J.; Nathenson, S.; Almo, S.

    2006-01-01

    The signaling lymphocytic activation molecule (SLAM) family includes homophilic and heterophilic receptors that regulate both innate and adaptive immunity. The ectodomains of most SLAM family members are composed of an N-terminal IgV domain and a C-terminal IgC2 domain. NK-T-B-antigen (NTB-A) is a homophilic receptor that stimulates cytotoxicity in natural killer (NK) cells, regulates bactericidal activities in neutrophils, and potentiates T helper 2 (Th2) responses. The 3.0 {angstrom} crystal structure of the complete NTB-A ectodomain revealed a rod-like monomer that self-associates to form a highly kinked dimer spanning an end-to-end distance of {approx}100 {angstrom}. The NTB-A homophilic and CD2-CD58 heterophilic dimers show overall structural similarities but differ in detailed organization and physicochemical properties of their respective interfaces. The NTB-A structure suggests a mechanism responsible for binding specificity within the SLAM family and imposes physical constraints relevant to the colocalization of SLAM-family proteins with other signaling molecules in the immunological synapse.

  12. Nuclear receptor NR1H3 in familial multiple sclerosis

    PubMed Central

    Wang, Zhe; Sadovnick, A. Dessa; Traboulsee, Anthony L.; Ross, Jay P.; Bernales, Cecily Q.; Encarnacion, Mary; Yee, Irene M.; de Lemos, Madonna; Greenwood, Talitha; Lee, Joshua D.; Wright, Galen; Ross, Colin J.; Zhang, Si; Song, Weihong; Vilariño-Güell, Carles

    2016-01-01

    SUMMARY Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss and neuronal dysfunction. Despite the aggregation observed in some families, pathogenic mutations have remained elusive. In this study we describe the identification of NR1H3 p.Arg415Gln in seven MS patients from two multi-incident families presenting severe and progressive disease, with an average age at onset of 34 years. Additionally, association analysis of common variants in NR1H3 identified rs2279238 conferring a 1.35-fold increased risk of developing progressive MS. The p.Arg415Gln position is highly conserved in orthologs and paralogs, and disrupts NR1H3 heterodimerization and transcriptional activation of target genes. Protein expression analysis revealed that mutant NR1H3 (LXRA) alters gene expression profiles, suggesting a disruption in transcriptional regulation as one of the mechanisms underlying MS pathogenesis. Our study indicates that pharmacological activation of LXRA or its targets may lead to effective treatments for the highly debilitating and currently untreatable progressive phase of MS. PMID:27253448

  13. Alcohol dependence, family history, and D2 dopamine receptor function as neuroendocrinologically assessed with apomorphine.

    PubMed

    Wiesbeck, G A; Mauerer, C; Thome, J; Jakob, F; Boening, J

    1995-11-01

    Fifteen alcohol dependent men with an alcohol dependent first degree relative (i.e. family history positive or FHP), 15 well matched alcohol dependent men without a family history for alcohol dependence (i.e. family history negative or FHN), and 15 healthy controls (CONTR) participated in this study. The three groups were compared according to their postsynaptic D2 dopamine receptor function as assessed by growth hormone release after stimulation with the dopamine receptor agonist apomorphine. Statistical evaluation was done by planned comparisons within a one-way ANOVA. Alcohol dependent subjects significantly differed from CONTRs as long as family history was not taken into account (t(42) = 2.38; P = 0.022*). When differentiating according to family history, both FHPs and FHNs maintained a blunted growth hormone response. However, the difference between FHNs and CONTRs, though present, dropped out of statistical significance (t(42) = 1.65; P = 0.105); at the same time, the difference between FHPs and CONTRs became slightly stronger (t(42) = 2.47; p = 0.017*). In conclusion, our data give neuroendocrinological support to the assumption that a reduced D2 dopamine receptor function in alcohol dependent men is not only a state marker of residual heavy drinking but also a genetically determined trait marker.

  14. Isolation and Characterization of ScGluD2, a New Sugarcane beta-1,3-Glucanase D Family Gene Induced by Sporisorium scitamineum, ABA, H2O2, NaCl, and CdCl2 Stresses

    PubMed Central

    Su, Yachun; Wang, Zhuqing; Liu, Feng; Li, Zhu; Peng, Qiong; Guo, Jinlong; Xu, Liping; Que, Youxiong

    2016-01-01

    Beta-1,3-glucanases (EC 3.2.1.39), commonly known as pathogenesis-related (PR) proteins, play an important role not only in plant defense against fungal pathogens but also in plant physiological and developmental processes. However, only a limited number of sugarcane beta-1,3-glucanase genes have been isolated. In the present study, we identified and characterized a new beta-1,3-glucanase gene ScGluD2 (GenBank Acc No. KF664181) from sugarcane. An X8 domain was present at the C terminal region of ScGluD2, suggesting beta-1,3-glucan-binding function. Phylogenetic analysis showed that the predicted ScGluD2 protein was classified into subfamily D beta-1,3-glucanase. Localization of the ScGluD2 protein in the plasma membrane was determined by tagging it with green fluorescent protein. The expression of ScGluD2 was more up-regulated in sugarcane smut-resistant cultivars in the early stage (1 or 3 days) than in the susceptible ones after being challenged by the smut pathogen, revealing that ScGluD2 may be involved in defense against the invasion of Sporisorium scitamineum. Transient overexpression of ScGluD2 in Nicotiana benthamiana leaves induced a defense response and exhibited antimicrobial action on the tobacco pathogens Pseudomonas solanacearum and Botrytis cinerea, further demonstrating that ScGluD2 was related to the resistance to plant pathogens. However, the transcripts of ScGluD2 partially increased (12 h) under NaCl stress, and were steadily up-regulated from 6 to 24 h upon ABA, H2O2, and CdCl2 treatments, suggesting that ABA may be a signal molecule regulating oxidative stress and play a role in the salt and heavy metal stress-induced stimulation of ScGluD2 transcripts. Taken together, ScGluD2, a novel member of subfamily D beta-1,3-glucanase, was a stress-related gene of sugarcane involved in plant defense against smut pathogen attack and salt and heavy metal stresses.

  15. Isolation and Characterization of ScGluD2, a New Sugarcane beta-1,3-Glucanase D Family Gene Induced by Sporisorium scitamineum, ABA, H2O2, NaCl, and CdCl2 Stresses.

    PubMed

    Su, Yachun; Wang, Zhuqing; Liu, Feng; Li, Zhu; Peng, Qiong; Guo, Jinlong; Xu, Liping; Que, Youxiong

    2016-01-01

    Beta-1,3-glucanases (EC 3.2.1.39), commonly known as pathogenesis-related (PR) proteins, play an important role not only in plant defense against fungal pathogens but also in plant physiological and developmental processes. However, only a limited number of sugarcane beta-1,3-glucanase genes have been isolated. In the present study, we identified and characterized a new beta-1,3-glucanase gene ScGluD2 (GenBank Acc No. KF664181) from sugarcane. An X8 domain was present at the C terminal region of ScGluD2, suggesting beta-1,3-glucan-binding function. Phylogenetic analysis showed that the predicted ScGluD2 protein was classified into subfamily D beta-1,3-glucanase. Localization of the ScGluD2 protein in the plasma membrane was determined by tagging it with green fluorescent protein. The expression of ScGluD2 was more up-regulated in sugarcane smut-resistant cultivars in the early stage (1 or 3 days) than in the susceptible ones after being challenged by the smut pathogen, revealing that ScGluD2 may be involved in defense against the invasion of Sporisorium scitamineum. Transient overexpression of ScGluD2 in Nicotiana benthamiana leaves induced a defense response and exhibited antimicrobial action on the tobacco pathogens Pseudomonas solanacearum and Botrytis cinerea, further demonstrating that ScGluD2 was related to the resistance to plant pathogens. However, the transcripts of ScGluD2 partially increased (12 h) under NaCl stress, and were steadily up-regulated from 6 to 24 h upon ABA, H2O2, and CdCl2 treatments, suggesting that ABA may be a signal molecule regulating oxidative stress and play a role in the salt and heavy metal stress-induced stimulation of ScGluD2 transcripts. Taken together, ScGluD2, a novel member of subfamily D beta-1,3-glucanase, was a stress-related gene of sugarcane involved in plant defense against smut pathogen attack and salt and heavy metal stresses. PMID:27642288

  16. Isolation and Characterization of ScGluD2, a New Sugarcane beta-1,3-Glucanase D Family Gene Induced by Sporisorium scitamineum, ABA, H2O2, NaCl, and CdCl2 Stresses

    PubMed Central

    Su, Yachun; Wang, Zhuqing; Liu, Feng; Li, Zhu; Peng, Qiong; Guo, Jinlong; Xu, Liping; Que, Youxiong

    2016-01-01

    Beta-1,3-glucanases (EC 3.2.1.39), commonly known as pathogenesis-related (PR) proteins, play an important role not only in plant defense against fungal pathogens but also in plant physiological and developmental processes. However, only a limited number of sugarcane beta-1,3-glucanase genes have been isolated. In the present study, we identified and characterized a new beta-1,3-glucanase gene ScGluD2 (GenBank Acc No. KF664181) from sugarcane. An X8 domain was present at the C terminal region of ScGluD2, suggesting beta-1,3-glucan-binding function. Phylogenetic analysis showed that the predicted ScGluD2 protein was classified into subfamily D beta-1,3-glucanase. Localization of the ScGluD2 protein in the plasma membrane was determined by tagging it with green fluorescent protein. The expression of ScGluD2 was more up-regulated in sugarcane smut-resistant cultivars in the early stage (1 or 3 days) than in the susceptible ones after being challenged by the smut pathogen, revealing that ScGluD2 may be involved in defense against the invasion of Sporisorium scitamineum. Transient overexpression of ScGluD2 in Nicotiana benthamiana leaves induced a defense response and exhibited antimicrobial action on the tobacco pathogens Pseudomonas solanacearum and Botrytis cinerea, further demonstrating that ScGluD2 was related to the resistance to plant pathogens. However, the transcripts of ScGluD2 partially increased (12 h) under NaCl stress, and were steadily up-regulated from 6 to 24 h upon ABA, H2O2, and CdCl2 treatments, suggesting that ABA may be a signal molecule regulating oxidative stress and play a role in the salt and heavy metal stress-induced stimulation of ScGluD2 transcripts. Taken together, ScGluD2, a novel member of subfamily D beta-1,3-glucanase, was a stress-related gene of sugarcane involved in plant defense against smut pathogen attack and salt and heavy metal stresses. PMID:27642288

  17. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

    PubMed Central

    Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

    2016-01-01

    Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

  18. Human T-cell receptor variable gene segment families

    SciTech Connect

    Arden, B.; Kabelitz, D.; Clark, S.P.; Mak, T.W.

    1995-10-01

    Multiple DNA and protein sequence alignments have been constructed for the human T-cell receptor {alpha}/{delta}, {beta}, and {gamma} (TCRA/D, B, and G) variable (V) gene segments. The traditional classification into subfamilies was confirmed using a much larger pool of sequences. For each sequence, a name was derived which complies with the standard nomenclature. The traditional numbering of V gene segments in the order of their discovery was continued and changed when in conflict with names of other segments. By discriminating between alleles at the same locus versus genes from different loci, we were able to reduce the number of more than 150 different TCRBV sequences in the database to a repertoire of only 47 functional TCRBV gene segments. An extension of this analysis to the over 100 TCRAV sequences results in a predicted repertoire of 42 functional TCRAV gene segments. Our alignment revealed two residues that distinguish between the highly homologous V{delta} and V{alpha}, one at a site that in V{sub H} contacts the constant region, the other at the interface between immunoglobulin V{sub H} and V{sub L}. This site may be responsible for restricted pairing between certain V{delta} and V{gamma} chains. On the other hand, V{beta} and V{gamma} appear to be related by the fact that their CDR2 length is increased by four residues as compared with that of V{alpha}/{delta} peptides. 150 refs., 12 figs., 5 tabs.

  19. CRDB: database of chemosensory receptor gene families in vertebrate.

    PubMed

    Dong, Dong; Jin, Ke; Wu, Xiaoli; Zhong, Yang

    2012-01-01

    Chemosensory receptors (CR) are crucial for animals to sense the environmental changes and survive on earth. The emergence of whole-genome sequences provides us an opportunity to identify the entire CR gene repertoires. To completely gain more insight into the evolution of CR genes in vertebrates, we identified the nearly all CR genes in 25 vertebrates using homology-based approaches. Among these CR gene repertoires, nearly half of them were identified for the first time in those previously uncharacterized species, such as the guinea pig, giant panda and elephant, etc. Consistent with previous findings, we found that the numbers of CR genes vary extensively among different species, suggesting an extreme form of 'birth-and-death' evolution. For the purpose of facilitating CR gene analysis, we constructed a database with the goals to provide a resource for CR genes annotation and a web tool for exploring their evolutionary patterns. Besides a search engine for the gene extraction from a specific chromosome region, an easy-to-use phylogenetic analysis tool was also provided to facilitate online phylogeny study of CR genes. Our work can provide a rigorous platform for further study on the evolution of CR genes in vertebrates.

  20. Chemical inhibition of potato ABA-8'-hydroxylase activity alters in vitro and in vivo ABA metabolism and endogenous ABA levels but does not affect potato microtuber dormancy duration.

    PubMed

    Suttle, Jeffrey C; Abrams, Suzanne R; De Stefano-Beltrán, Luis; Huckle, Linda L

    2012-09-01

    The effects of azole-type P450 inhibitors and two metabolism-resistant abscisic acid (ABA) analogues on in vitro ABA-8'-hydroxylase activity, in planta ABA metabolism, endogenous ABA content, and tuber meristem dormancy duration were examined in potato (Solanum tuberosum L. cv. Russet Burbank). When functionally expressed in yeast, three potato CYP707A genes were demonstrated to encode enzymatically active ABA-8'-hydroxylases with micromolar affinities for (+)-ABA. The in vitro activity of the three enzymes was inhibited by the P450 azole-type inhibitors ancymidol, paclobutrazol, diniconazole, and tetcyclasis, and by the 8'-acetylene- and 8'-methylene-ABA analogues, with diniconazole and tetcyclasis being the most potent inhibitors. The in planta metabolism of [(3)H](±)-ABA to phaseic acid and dihydrophaseic acid in tuber meristems was inhibited by diniconazole, tetcyclasis, and to a lesser extent by 8'-acetylene- and 8'-methylene-ABA. Continuous exposure of in vitro generated microtubers to diniconazole resulted in a 2-fold increase in endogenous ABA content and a decline in dihydrophaseic acid content after 9 weeks of development. Similar treatment with 8'-acetylene-ABA had no effects on the endogenous contents of ABA or phaseic acid but reduced the content of dihydrophaseic acid. Tuber meristem dormancy progression was determined ex vitro in control, diniconazole-, and 8'-acetylene-ABA-treated microtubers following harvest. Continuous exposure to diniconazole during microtuber development had no effects on subsequent sprouting at any time point. Continuous exposure to 8'-acetylene-ABA significantly increased the rate of microtuber sprouting. The results indicate that, although a decrease in ABA content is a hallmark of tuber dormancy progression, the decline in ABA levels is not a prerequisite for dormancy exit and the onset of tuber sprouting.

  1. Evolution of spatially coexpressed families of type-2 vomeronasal receptors in rodents.

    PubMed

    Francia, Simona; Silvotti, Lucia; Ghirardi, Filippo; Catzeflis, François; Percudani, Riccardo; Tirindelli, Roberto

    2014-12-23

    The vomeronasal organ (VNO) is an olfactory structure for the detection of pheromones. VNO neurons express three groups of unrelated G-protein-coupled receptors. Type-2 vomeronasal receptors (V2Rs) are specifically localized in the basal neurons of the VNO and are believed to sense protein pheromones eliciting specific reproductive behaviors. In murine species, V2Rs are organized into four families. Family-ABD V2Rs are expressed monogenically and coexpress with family-C V2Rs of either subfamily C1 (V2RC1) or subfamily C2 (V2RC2), according to a coordinate temporal diagram. Neurons expressing the phylogenetically ancient V2RC1 coexpress family-BD V2Rs or a specific group of subfamily-A V2Rs (V2RA8-10), whereas a second neuronal subset (V2RC2-positive) coexpresses a recently expanded group of five subfamily-A V2Rs (V2RA1-5) along with vomeronasal-specific Major Histocompatibility Complex molecules (H2-Mv). Through database mining and Sanger sequencing, we have analyzed the onset, diversification, and expansion of the V2R-families throughout the phylogeny of Rodentia. Our results suggest that the separation of V2RC1 and V2RC2 occurred in a Cricetidae ancestor in coincidence with the evolution of the H2-Mv genes; this phylogenetic event did not correspond with the origin of the coexpressing V2RA1-5 genes, which dates back to an ancestral myomorphan lineage. Interestingly, the evolution of receptors within the V2RA1-5 group may be implicated in the origin and diversification of some of the V2R putative cognate ligands, the exocrine secreting peptides. The establishment of V2RC2, which probably reflects the complex expansion and diversification of family-A V2Rs, generated receptors that have probably acquired a more subtle functional specificity.

  2. Trace Amine-Associated Receptor 1 – Family Archetype or Iconoclast?

    PubMed Central

    Grandy, David K.

    2009-01-01

    Interest has recently been rekindled in receptors that are activated by low molecular weight, non-catecholic, biogenic amines that are typically found as trace constituents of various vertebrate and invertebrate tissues and fluids. The timing of this resurgent focus on receptors activated by the ‘trace amines’ (TAs) β-phenylethylamine (PEA), tyramine (TYR), octopamine (OCT), synephrine (SYN), and tryptamine (TRYP) is the direct result of two publications that appeared in 2001 describing the cloning of a novel G protein-coupled receptor (GPCR) referred to by their discoverers as TA1 (Borowsky et al., 2001) and TAR1 (Bunzow et al., 2001). When heterologously expressed in Xenopus laevis oocytes and various eukaryotic cell lines recombinant rodent and human TA receptors dose-dependently couple to the stimulation of cAMP production. Structure-activity profiling based on this functional response has revealed that in addition to the TAs, other biologically active compounds containing a 2 carbon aliphatic side chain linking an amino group to at least one benzene ring are potent and efficacious TA receptor agonists with amphetamine, methamphetamine, 3-iodothyronamine, thyronamine, and dopamine among the most notable. Almost 100 years after the search for TA receptors began numerous TA1/TAR1-related sequences, now called Trace Amine-Associated Receptors (TAARs), have been identified in the genome of every species of vertebrate examined to date. Consequently, even though heterologously expressed TAAR1 fits the pharmacological criteria established for a bona fide TA receptor a major challenge for those working in the field is to discern the in vivo pharmacology and physiology of each purported member of this extended family of GPCRs. Only then will it be possible to establish whether TAAR1 is the family archetype or an iconoclast. PMID:17888514

  3. Differential Binding Activity of TGF-β Family Proteins to Select TGF-β Receptors.

    PubMed

    Khalil, Ashraf M; Dotimas, Hyna; Kahn, Julius; Lamerdin, Jane E; Hayes, David B; Gupta, Priyanka; Franti, Michael

    2016-09-01

    Growth differentiation factor-11 (GDF11) and myostatin (MSTN) are highly related transforming growth factor-β (TGF-β) ligands with 89% amino acid sequence homology. They have different biologic activities and diverse tissue distribution patterns. However, the activities of these ligands are indistinguishable in in vitro assays. SMAD2/3 signaling has been identified as the canonical pathway for GDF11 and MSTN, However, it remains unclear which receptor heterodimer and which antagonists preferentially mediate and regulate signaling. In this study, we investigated the initiation and regulation of GDF11 and MSTN signaling at the receptor level using a novel receptor dimerization detection technology. We used the dimerization platform to link early receptor binding events to intracellular downstream signaling. This approach was instrumental in revealing differential receptor binding activity within the TGF-β family. We verified the ActR2b/ALK5 heterodimer as the predominant receptor for GDF11- and MSTN-induced SMAD2/3 signaling. We also showed ALK7 specifically mediates activin-B signaling. We verified follistatin as a potent antagonist to neutralize both SMAD2/3 signaling and receptor dimerization. More remarkably, we showed that the two related antagonists, growth and differentiation factor-associated serum protein (GASP)-1 and GASP2, differentially regulate GDF11 (and MSTN) signaling. GASP1 blocks both receptor dimerization and downstream signaling. However, GASP2 blocks only downstream signaling without interference from receptor dimerization. Our data strongly suggest that physical binding of GDF11 (and MSTN) to both ActR2b and ALK5 receptors is required for initiation of signaling. PMID:27340210

  4. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors

    PubMed Central

    Culhane, Kelly J.; Liu, Yuting; Cai, Yingying; Yan, Elsa C. Y.

    2015-01-01

    Although family B G protein-coupled receptors (GPCRs) contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs. PMID:26594176

  5. Isolation and characterization of novel mutant loci suppressing the ABA hypersensitivity of the Arabidopsis coronatine insensitive 1-16 (coi1-16) mutant during germination and seedling growth.

    PubMed

    Fernández-Arbaizar, Alejandro; Regalado, José J; Lorenzo, Oscar

    2012-01-01

    The phytohormone ABA regulates seed germination and stress responses. The identification of clade A protein phosphatase type 2C (PP2C)-interacting proteins PYRABACTIN RESISTANCE 1 (PYR1)/RCAR (REGULATORY COMPONENT OF ABA RECEPTOR) and PYR1-LIKEs (PYLs) as ABA receptors has been a major advance in understanding this process. Here, our aim was to identify additional ABA response loci by suppressor screening of the jasmonate (JA)-insensitive coronatine insensitive 1-16 (coi1-16) mutant using its ABA-hypersensitive phenotype. The identification and genetic characterization of Coi1-16 Resistant to ABA (CRA) loci revealed several unknown and three previously known abi mutants (abi1, abi3 and abi4), thus providing proof-of-concept evidence for this study. The synergistic effect of ABA and JA on seed germination and cotyledon expansion was analyzed in depth and the roles of cra5 coi1-16, cra6 coi1-16, cra7 coi1-16 and cra8 coi1-16 in ABA signaling during seed germination and stress responses were functionally characterized. The cra5 coi1-16 mutant showed resistance to ABA, paclobutrazol, and abiotic stresses during germination and early developmental stages. Furthermore, the cra5 coi1-16 mutation was mapped to the short arm of chromosome V and mutants exhibited differential expression of ABA-responsive genes, suggesting that CRA5 may function as a positive regulator of ABA signaling. Interestingly, cra6 coi1-16, cra7 coi1-16 and cra8 coi1-16 mutants display similar ABA- and abiotic stress-insensitive phenotypes during seed germination and seedling establishment. Taken together, our results demonstrate a key role for CRA genes in regulating the onset of seed germination by ABA, and highlight how cra mutants can be used as powerful tools to analyze novel molecular components of ABA signaling in seeds. PMID:22156383

  6. GsAPK, an ABA-activated and calcium-independent SnRK2-type kinase from G. soja, mediates the regulation of plant tolerance to salinity and ABA stress.

    PubMed

    Yang, Liang; Ji, Wei; Gao, Peng; Li, Yong; Cai, Hua; Bai, Xi; Chen, Qin; Zhu, Yanming

    2012-01-01

    Plant Snf1 (sucrose non-fermenting-1) related protein kinase (SnRK), a subfamily of serine/threonine kinases, has been implicated as a crucial upstream regulator of ABA and osmotic signaling as in many other signaling cascades. In this paper, we have isolated a novel plant specific ABA activated calcium independent protein kinase (GsAPK) from a highly salt tolerant plant, Glycine soja (50109), which is a member of the SnRK2 family. Subcellular localization studies using GFP fusion protein indicated that GsAPK is localized in the plasma membrane. We found that autophosphorylation and Myelin Basis Protein phosphorylation activity of GsAPK is only activated by ABA and the kinase activity also was observed when calcium was replaced by EGTA, suggesting its independence of calcium in enzyme activity. We also found that cold, salinity, drought, and ABA stress alter GsAPK gene transcripts and heterogonous overexpression of GsAPK in Arabidopsis alters plant tolerance to high salinity and ABA stress. In summary, we demonstrated that GsAPK is a Glycine soja ABA activated calcium independent SnRK-type kinase presumably involved in ABA mediated stress signal transduction.

  7. Consequences of splice variation on Secretin family G protein-coupled receptor function

    PubMed Central

    Furness, Sebastian GB; Wootten, Denise; Christopoulos, Arthur; Sexton, Patrick M

    2012-01-01

    The Secretin family of GPCRs are endocrine peptide hormone receptors that share a common genomic organization and are the subject of a wide variety of alternative splicing. All GPCRs contain a central seven transmembrane domain responsible for transducing signals from the outside of the cell as well as extracellular amino and intracellular carboxyl termini. Members of the Secretin receptor family have a relatively large N-terminus and a variety of lines of evidence support a common mode of ligand binding and a common ligand binding fold. These receptors are best characterized as coupling to intracellular signalling pathways via Gαs and Gαq but are also reported to couple to a multitude of other signalling pathways. The intracellular loops are implicated in regulating the interaction between the receptor and heterotrimeric G protein complexes. Alternative splicing of exons encoding both the extracellular N-terminal domain as well as the extracellular loops of some family members has been reported and as expected these splice variants display altered ligand affinity as well as differential activation by endogenous ligands. Various forms of alternative splicing have also been reported to alter intracellular loops 1 and 3 as well as the C-terminus and as one might expect these display differences in signalling bias towards downstream effectors. These diverse pharmacologies require that the physiological role of these splice variants be addressed but should provide unique opportunities for drug design and development. LINKED ARTICLES This article is part of a themed section on Secretin Family (Class B) G Protein-Coupled Receptors. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.166.issue-1 PMID:21718310

  8. Novel Fc gamma receptor I family gene products in human mononuclear cells.

    PubMed Central

    Porges, A J; Redecha, P B; Doebele, R; Pan, L C; Salmon, J E; Kimberly, R P

    1992-01-01

    Unlike the human Fc gamma RII and Fc gamma RIII families, which exhibit considerable diversity at both the nucleic acid and protein levels, the human Fc gamma RI family has only a single recognized product expressed as a 70-kD cell surface receptor with high affinity for monomeric IgG (hFc gamma RIa1). Using both polymerase chain reaction-based amplification and Northern hybridization, we document multiple interferon-gamma-inducible hFc gamma RI RNA transcripts in human mononuclear cells and neutrophils. The sequences of two of these Fc gamma RI related transcripts indicate that they are alternatively spliced products of a second Fc gamma RI family gene, termed Fc gamma RIB. The cDNA derived from the larger of these transcripts, termed hFc gamma RIb1, encodes a surface molecule that is not recognized by Fc gamma RI specific monoclonal antibodies when transfected into COS-7 cells. Unlike the interferon-gamma-inducible hFc gamma RIA gene product, hFc gamma RIb1 does not bind monomeric IgG with high affinity. However, both hFc gamma RIa1 and hFc gamma RIb1 do bind aggregated human IgG. Previously unrecognized diversity within the hFc gamma RI family includes an interferon-gamma-inducible, putative low affinity Fc gamma receptor that may play an important role in the mechanism by which Fc gamma receptors participate in the humoral immune response. Images PMID:1430234

  9. Natural killer cell receptor genes in the family Equidae: not only Ly49.

    PubMed

    Futas, Jan; Horin, Petr

    2013-01-01

    Natural killer (NK) cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR) and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR) represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA) and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM) domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for evolutionary biology of

  10. Natural Killer Cell Receptor Genes in the Family Equidae: Not only Ly49

    PubMed Central

    Futas, Jan; Horin, Petr

    2013-01-01

    Natural killer (NK) cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR) and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR) represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA) and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM) domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for evolutionary biology of

  11. Natural killer cell receptor genes in the family Equidae: not only Ly49.

    PubMed

    Futas, Jan; Horin, Petr

    2013-01-01

    Natural killer (NK) cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR) and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR) represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA) and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM) domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for evolutionary biology of

  12. Methuselah/Methuselah-like G protein-coupled receptors constitute an ancient metazoan gene family

    PubMed Central

    de Mendoza, Alexandre; Jones, Jeffery W.; Friedrich, Markus

    2016-01-01

    Inconsistent conclusions have been drawn regarding the phylogenetic age of the Methuselah/Methuselah-like (Mth/Mthl) gene family of G protein-coupled receptors, the founding member of which regulates development and lifespan in Drosophila. Here we report the results from a targeted homolog search of 39 holozoan genomes and phylogenetic analysis of the conserved seven transmembrane domain. Our findings reveal that the Mth/Mthl gene family is ancient, has experienced numerous extinction and expansion events during metazoan evolution, and acquired the current definition of the Methuselah ectodomain during its exceptional expansion in arthropods. In addition, our findings identify Mthl1, Mthl5, Mthl14, and Mthl15 as the oldest Mth/Mthl gene family paralogs in Drosophila. Future studies of these genes have the potential to define ancestral functions of the Mth/Mthl gene family. PMID:26915348

  13. Auxiliary subunits of the CKAMP family differentially modulate AMPA receptor properties

    PubMed Central

    Farrow, Paul; Khodosevich, Konstantin; Sapir, Yechiam; Schulmann, Anton; Aslam, Muhammad

    2015-01-01

    AMPA receptor (AMPAR) function is modulated by auxiliary subunits. Here, we report on three AMPAR interacting proteins—namely CKAMP39, CKAMP52 and CKAMP59—that, together with the previously characterized CKAMP44, constitute a novel family of auxiliary subunits distinct from other families of AMPAR interacting proteins. The new members of the CKAMP family display distinct regional and developmental expression profiles in the mouse brain. Notably, despite their structural similarities they exert diverse modulation on AMPAR gating by influencing deactivation, desensitization and recovery from desensitization, as well as glutamate and cyclothiazide potency to AMPARs. This study indicates that AMPAR function is very precisely controlled by the cell-type specific expression of the CKAMP family members. DOI: http://dx.doi.org/10.7554/eLife.09693.001 PMID:26623514

  14. A diverse family of proteins containing tumor necrosis factor receptor-associated factor domains.

    PubMed

    Zapata, J M; Pawlowski, K; Haas, E; Ware, C F; Godzik, A; Reed, J C

    2001-06-29

    We have identified three new tumor necrosis factor-receptor associated factor (TRAF) domain-containing proteins in humans using bioinformatics approaches, including: MUL, the product of the causative gene in Mulibrey Nanism syndrome; USP7 (HAUSP), an ubiquitin protease; and SPOP, a POZ domain-containing protein. Unlike classical TRAF family proteins involved in TNF family receptor (TNFR) signaling, the TRAF domains (TDs) of MUL, USP7, and SPOP are located near the NH(2) termini or central region of these proteins, rather than carboxyl end. MUL and USP7 are capable of binding in vitro via their TDs to all of the previously identified TRAF family proteins (TRAF1, TRAF2, TRAF3, TRAF4, TRAF5, and TRAF6), whereas the TD of SPOP interacts weakly with TRAF1 and TRAF6 only. The TD of MUL also interacted with itself, whereas the TDs of USP7 and SPOP did not self-associate. Analysis of various MUL and USP7 mutants by transient transfection assays indicated that the TDs of these proteins are necessary and sufficient for suppressing NF-kappaB induction by TRAF2 and TRAF6 as well as certain TRAF-binding TNF family receptors. In contrast, the TD of SPOP did not inhibit NF-kappaB induction. Immunofluorescence confocal microscopy indicated that MUL localizes to cytosolic bodies, with targeting to these structures mediated by a RBCC tripartite domain within the MUL protein. USP7 localized predominantly to the nucleus, in a TD-dependent manner. Data base searches revealed multiple proteins containing TDs homologous to those found in MUL, USP7, and SPOP throughout eukaryotes, including yeast, protists, plants, invertebrates, and mammals, suggesting that this branch of the TD family arose from an ancient gene. We propose the moniker TEFs (TD-encompassing factors) for this large family of proteins.

  15. A Comparative Structural Bioinformatics Analysis of the Insulin Receptor Family Ectodomain Based on Phylogenetic Information

    PubMed Central

    Rentería, Miguel E.; Gandhi, Neha S.; Vinuesa, Pablo; Helmerhorst, Erik; Mancera, Ricardo L.

    2008-01-01

    The insulin receptor (IR), the insulin-like growth factor 1 receptor (IGF1R) and the insulin receptor-related receptor (IRR) are covalently-linked homodimers made up of several structural domains. The molecular mechanism of ligand binding to the ectodomain of these receptors and the resulting activation of their tyrosine kinase domain is still not well understood. We have carried out an amino acid residue conservation analysis in order to reconstruct the phylogeny of the IR Family. We have confirmed the location of ligand binding site 1 of the IGF1R and IR. Importantly, we have also predicted the likely location of the insulin binding site 2 on the surface of the fibronectin type III domains of the IR. An evolutionary conserved surface on the second leucine-rich domain that may interact with the ligand could not be detected. We suggest a possible mechanical trigger of the activation of the IR that involves a slight ‘twist’ rotation of the last two fibronectin type III domains in order to face the likely location of insulin. Finally, a strong selective pressure was found amongst the IRR orthologous sequences, suggesting that this orphan receptor has a yet unknown physiological role which may be conserved from amphibians to mammals. PMID:18989367

  16. Mannose Phosphate Isomerase Regulates Fibroblast Growth Factor Receptor Family Signaling and Glioma Radiosensitivity

    PubMed Central

    Cazet, Aurélie; Charest, Jonathan; Bennett, Daniel C.; Sambrooks, Cecilia Lopez; Contessa, Joseph N.

    2014-01-01

    Asparagine-linked glycosylation is an endoplasmic reticulum co- and post- translational modification that enables the transit and function of receptor tyrosine kinase (RTK) glycoproteins. To gain insight into the regulatory role of glycosylation enzymes on RTK function, we investigated shRNA and siRNA knockdown of mannose phosphate isomerase (MPI), an enzyme required for mature glycan precursor biosynthesis. Loss of MPI activity reduced phosphorylation of FGFR family receptors in U-251 and SKMG-3 malignant glioma cell lines and also resulted in significant decreases in FRS2, Akt, and MAPK signaling. However, MPI knockdown did not affect ligand-induced activation or signaling of EGFR or MET RTKs, suggesting that FGFRs are more susceptible to MPI inhibition. The reductions in FGFR signaling were not caused by loss of FGF ligands or receptors, but instead were caused by interference with receptor dimerization. Investigations into the cellular consequences of MPI knockdown showed that cellular programs driven by FGFR signaling, and integral to the clinical progression of malignant glioma, were impaired. In addition to a blockade of cellular migration, MPI knockdown also significantly reduced glioma cell clonogenic survival following ionizing radiation. Therefore our results suggest that targeted inhibition of enzymes required for cell surface receptor glycosylation can be manipulated to produce discrete and limited consequences for critical client glycoproteins expressed by tumor cells. Furthermore, this work identifies MPI as a potential enzymatic target for disrupting cell surface receptor-dependent survival signaling and as a novel approach for therapeutic radiosensitization. PMID:25314669

  17. IL-12 Family Cytokines: General Characteristics, Pathogenic Microorganisms, Receptors, and Signalling Pathways.

    PubMed

    Behzadi, Payam; Behzadi, Elham; Ranjbar, Reza

    2016-03-01

    Among a wide range of cytokines, the Interleukin 12 (IL-12) family has its unique structural, functional, and immunological characteristics that have made this family as important immunological playmakers. Because of the importance of IL-12 heterodimeric cytokines in microbial infections, autoimmune diseases, and cancers, the authors of this literature discuss about the general characteristics of IL-12 family members, the interactions between IL-12 cytokines and pathogenic microorganisms, the interleukins receptors and their strategies for selecting different signalling pathways. IL-12 and IL-23 are similar in p40 subunits and both are involved in proinflammatory responses while, IL-27 and IL-35 contribute to anti-inflammatory activities; however, IL-27 is also involved in pro-inflammatory responses. There are some similarities and dissimilarities among IL-12 family members which make them a unique bridge between innate and adaptive immune systems. The bioactivities of IL-12 family indicate a brilliant promise for their applications in different fields of medicine. The members of IL-12 family are candidate for several therapeutics including gene therapy, cancer therapy, tumour therapy, and vaccination. To have an accurate diagnostic technique and definite treatment regarding to infectious diseases, the playmakers of IL-12 family as effective criteria together with microarray technology are the best choices for current and future applications.

  18. IL-12 Family Cytokines: General Characteristics, Pathogenic Microorganisms, Receptors, and Signalling Pathways.

    PubMed

    Behzadi, Payam; Behzadi, Elham; Ranjbar, Reza

    2016-03-01

    Among a wide range of cytokines, the Interleukin 12 (IL-12) family has its unique structural, functional, and immunological characteristics that have made this family as important immunological playmakers. Because of the importance of IL-12 heterodimeric cytokines in microbial infections, autoimmune diseases, and cancers, the authors of this literature discuss about the general characteristics of IL-12 family members, the interactions between IL-12 cytokines and pathogenic microorganisms, the interleukins receptors and their strategies for selecting different signalling pathways. IL-12 and IL-23 are similar in p40 subunits and both are involved in proinflammatory responses while, IL-27 and IL-35 contribute to anti-inflammatory activities; however, IL-27 is also involved in pro-inflammatory responses. There are some similarities and dissimilarities among IL-12 family members which make them a unique bridge between innate and adaptive immune systems. The bioactivities of IL-12 family indicate a brilliant promise for their applications in different fields of medicine. The members of IL-12 family are candidate for several therapeutics including gene therapy, cancer therapy, tumour therapy, and vaccination. To have an accurate diagnostic technique and definite treatment regarding to infectious diseases, the playmakers of IL-12 family as effective criteria together with microarray technology are the best choices for current and future applications. PMID:27020866

  19. Identification of Arabidopsis thaliana NRT1/PTR FAMILY (NPF) proteins capable of transporting plant hormones.

    PubMed

    Chiba, Yasutaka; Shimizu, Takafumi; Miyakawa, Shinya; Kanno, Yuri; Koshiba, Tomokazu; Kamiya, Yuji; Seo, Mitsunori

    2015-07-01

    NRT1/PTR FAMILY (NPF) proteins were originally identified as nitrate or di/tri-peptide transporters. Recent studies revealed that this transporter family also transports the plant hormones auxin (indole-3-acetic acid), abscisic acid (ABA), and gibberellin (GA), as well as secondary metabolites (glucosinolates). We developed modified yeast two-hybrid systems with receptor complexes for GA and jasmonoyl-isoleucine (JA-Ile), to detect GA and JA-Ile transport activities of proteins expressed in the yeast cells. Using these GA and JA-Ile systems as well as the ABA system that we had introduced previously, we determined the capacities of Arabidopsis NPFs to transport these hormones. Several NPFs induced the formation of receptor complexes under relatively low hormone concentrations. Hormone transport activities were confirmed for some NPFs by direct analysis of hormone uptake of yeast cells by liquid chromatography-tandem mass spectrometry. Our results suggest that at least some NPFs could function as hormone transporters.

  20. Endocytosis and the Src family of non-receptor tyrosine kinases.

    PubMed

    Reinecke, James; Caplan, Steve

    2014-05-01

    The regulated intracellular transport of nutrient, adhesion, and growth factor receptors is crucial for maintaining cell and tissue homeostasis. Endocytosis, or endocytic membrane trafficking, involves the steps of intracellular transport that include, but are not limited to, internalization from the plasma membrane, sorting in early endosomes, transport to late endosomes/lysosomes followed by degradation, and/or recycling back to the plasma membrane through tubular recycling endosomes. In addition to regulating the localization of transmembrane receptor proteins, the endocytic pathway also controls the localization of non-receptor molecules. The non-receptor tyrosine kinase c-Src (Src) and its closely related family members Yes and Fyn represent three proteins whose localization and signaling activities are tightly regulated by endocytic trafficking. Here, we provide a brief overview of endocytosis, Src function and its biochemical regulation. We will then concentrate on recent advances in understanding how Src intracellular localization is regulated and how its subcellular localization ultimately dictates downstream functioning. As Src kinases are hyperactive in many cancers, it is essential to decipher the spatiotemporal regulation of this important family of tyrosine kinases. PMID:25372749

  1. A novel fibroblast growth factor receptor family member promotes neuronal outgrowth and synaptic plasticity in aplysia.

    PubMed

    Pollak, Daniela D; Minh, Bui Quang; Cicvaric, Ana; Monje, Francisco J

    2014-11-01

    Fibroblast Growth Factor (FGF) Receptors (FGFRs) regulate essential biological processes, including embryogenesis, angiogenesis, cellular growth and memory-related long-term synaptic plasticity. Whereas canonical FGFRs depend exclusively on extracellular Immunoglobulin (Ig)-like domains for ligand binding, other receptor types, including members of the tropomyosin-receptor-kinase (Trk) family, use either Ig-like or Leucine-Rich Repeat (LRR) motifs, or both. Little is known, however, about the evolutionary events leading to the differential incorporation of LRR domains into Ig-containing tyrosine kinase receptors. Moreover, although FGFRs have been identified in many vertebrate species, few reports describe their existence in invertebrates. Information about the biological relevance of invertebrate FGFRs and evolutionary divergences between them and their vertebrate counterparts is therefore limited. Here, we characterized ApLRRTK, a neuronal cell-surface protein recently identified in Aplysia. We unveiled ApLRRTK as the first member of the FGFRs family deprived of Ig-like domains that instead contains extracellular LRR domains. We describe that ApLRRTK exhibits properties typical of canonical vertebrate FGFRs, including promotion of FGF activity, enhancement of neuritic outgrowth and signaling via MAPK and the transcription factor CREB. ApLRRTK also enhanced the synaptic efficiency of neurons known to mediate in vivo memory-related defensive behaviors. These data reveal a novel molecular regulator of neuronal function in invertebrates, provide the first evolutionary linkage between LRR proteins and FGFRs and unveil an unprecedented mechanism of FGFR gene diversification in primeval central nervous systems.

  2. The acidic domains of the Toc159 chloroplast preprotein receptor family are intrinsically disordered protein domains

    PubMed Central

    2009-01-01

    Background The Toc159 family of proteins serve as receptors for chloroplast-destined preproteins. They directly bind to transit peptides, and exhibit preprotein substrate selectivity conferred by an unknown mechanism. The Toc159 receptors each include three domains: C-terminal membrane, central GTPase, and N-terminal acidic (A-) domains. Although the function(s) of the A-domain remains largely unknown, the amino acid sequences are most variable within these domains, suggesting they may contribute to the functional specificity of the receptors. Results The physicochemical properties of the A-domains are characteristic of intrinsically disordered proteins (IDPs). Using CD spectroscopy we show that the A-domains of two Arabidopsis Toc159 family members (atToc132 and atToc159) are disordered at physiological pH and temperature and undergo conformational changes at temperature and pH extremes that are characteristic of IDPs. Conclusions Identification of the A-domains as IDPs will be important for determining their precise function(s), and suggests a role in protein-protein interactions, which may explain how these proteins serve as receptors for such a wide variety of preprotein substrates. PMID:20042108

  3. The D1 family dopamine receptor, DopR, potentiates hind leg grooming behavior in Drosophila

    PubMed Central

    Pitmon, E.; Stephens, G.; Parkhurst, S. J.; Wolf, F. W.; Kehne, G.; Taylor, M.

    2016-01-01

    Drosophila groom away debris and pathogens from the body using their legs in a stereotyped sequence of innate motor behaviors. Here, we investigated one aspect of the grooming repertoire by characterizing the D1 family dopamine receptor, DopR. Removal of DopR results in decreased hind leg grooming, as substantiated by quantitation of dye remaining on mutant and RNAi animals vs. controls and direct scoring of behavioral events. These data are also supported by pharmacological results that D1 receptor agonists fail to potentiate grooming behaviors in headless DopR flies. DopR protein is broadly expressed in the neuropil of the thoracic ganglion and overlaps with TH‐positive dopaminergic neurons. Broad neuronal expression of dopamine receptor in mutant animals restored normal grooming behaviors. These data provide evidence for the role of DopR in potentiating hind leg grooming behaviors in the thoracic ganglion of adult Drosophila. This is a remarkable juxtaposition to the considerable role of D1 family dopamine receptors in rodent grooming, and future investigations of evolutionary relationships of circuitry may be warranted. PMID:26749475

  4. A gene recently inactivated in human defines a new olfactory receptor family in mammals.

    PubMed

    Rouquier, S; Friedman, C; Delettre, C; van den Engh, G; Blancher, A; Crouau-Roy, B; Trask, B J; Giorgi, D

    1998-09-01

    The olfactory receptor (OR) gene family constitutes one of the largest multigene families and is distributed among many chromosomal sites in the human genome. Four OR families have been defined in mammals. We previously demonstrated that a high fraction of human OR sequences have incurred deleterious mutations, thus reducing the repertoire of functional OR genes. In this study, we have characterized a new OR gene, 912-93, in primates. This gene is unique and it defines a new OR family. It localizes to human chromosome 11q11-12 and at syntenical sites in other hominoids. The sequence marks a previously unrecognized rearrangement of pericentromeric material from chromosome 11 to the centromeric region of gibbon chromosome 5. The human gene contains a nonsense point mutation in the region corresponding to the extracellular N-terminus of the receptor. This mutation is present in humans of various ethnic groups, but is absent in apes, suggesting that it probably appeared during the divergence of humans from other apes, <4 000 000-5 000 000 years ago. A second mutation, a frameshift at a different location, has occurred in the gorilla copy of this gene. These observations suggest that OR 912-93 has been recently silenced in human and gorilla, adding to a pool of OR pseudogenes whose growth may parallel a reduction in the sense of smell in primates.

  5. A critical role of nucleus accumbens dopamine D1-family receptors in renewal of alcohol seeking after punishment-imposed abstinence.

    PubMed

    Marchant, Nathan J; Kaganovsky, Konstantin

    2015-06-01

    In humans, places or contexts previously associated with alcohol use often provoke relapse during abstinence. This phenomenon is modeled in laboratory animals using the ABA renewal procedure, in which extinction training in context (B) suppresses alcohol seeking, and renewal of this seeking occurs when the animal returns to the original training context (A). However, extinction training does not adequately capture the motivation for abstinence in human alcoholics who typically self-initiate abstinence in response to the negative consequences of excessive use. We recently developed a procedure to study renewal in laboratory rats after abstinence imposed by negative consequences (footshock punishment). The mechanisms of renewal of punished alcohol seeking are largely unknown. Here, we used the D1-family receptor antagonist SCH 23390 to examine the role of nucleus accumbens (NAc) shell and core dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We trained alcohol-preferring "P rats" to self-administer 20% alcohol in Context A and subsequently suppressed alcohol taking via response-contingent footshock punishment in Context B. We tested the effects of systemic, NAc shell, or NAc core injections of SCH 23390 on renewal of alcohol seeking after punishment-imposed abstinence. We found that both systemic and NAc shell and core injections of SCH 23390 decreased renewal of punished alcohol seeking. Our results demonstrate a critical role of NAc dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We discuss these results in reference to the brain mechanisms of renewal of alcohol seeking after extinction versus punishment. PMID:25914922

  6. A critical role of nucleus accumbens dopamine D1-family receptors in renewal of alcohol seeking after punishment-imposed abstinence

    PubMed Central

    Marchant, Nathan J.; Kaganovsky, Konstantin

    2015-01-01

    In humans, places or contexts previously associated with alcohol use often provoke relapse during abstinence. This phenomenon is modeled in laboratory animals using the ABA renewal procedure, where alcohol seeking that is suppressed with extinction training in a context (B) renews when the animal returns to the original training context (A). However, extinction training does not adequately capture the motivation for abstinence in human alcoholics who typically self-initiate abstinence due to the negative consequences of excessive use. We recently developed a procedure to study renewal in laboratory rats after abstinence is imposed by negative consequences (footshock punishment). The mechanisms of renewal of punished alcohol seeking are largely unknown. Here we used the D1-family receptor antagonist SCH 23390 to examine the role of nucleus accumbens (NAc) shell and core dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We trained alcohol preferring ‘P rats’ to self-administer 20% alcohol in context A and subsequently suppressed alcohol taking via response-contingent footshock punishment in context B. We tested the effects of systemic, NAc shell, or NAc core injections of SCH 23390 on renewal of alcohol seeking after punishment-imposed abstinence. We found that both systemic and NAc shell and core injections of SCH 23390 decreased renewal of punished alcohol seeking. Our results demonstrate a critical role of NAc dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We discuss these results in reference to the brain mechanisms of renewal of alcohol seeking after extinction versus punishment. PMID:25914922

  7. A critical role of nucleus accumbens dopamine D1-family receptors in renewal of alcohol seeking after punishment-imposed abstinence.

    PubMed

    Marchant, Nathan J; Kaganovsky, Konstantin

    2015-06-01

    In humans, places or contexts previously associated with alcohol use often provoke relapse during abstinence. This phenomenon is modeled in laboratory animals using the ABA renewal procedure, in which extinction training in context (B) suppresses alcohol seeking, and renewal of this seeking occurs when the animal returns to the original training context (A). However, extinction training does not adequately capture the motivation for abstinence in human alcoholics who typically self-initiate abstinence in response to the negative consequences of excessive use. We recently developed a procedure to study renewal in laboratory rats after abstinence imposed by negative consequences (footshock punishment). The mechanisms of renewal of punished alcohol seeking are largely unknown. Here, we used the D1-family receptor antagonist SCH 23390 to examine the role of nucleus accumbens (NAc) shell and core dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We trained alcohol-preferring "P rats" to self-administer 20% alcohol in Context A and subsequently suppressed alcohol taking via response-contingent footshock punishment in Context B. We tested the effects of systemic, NAc shell, or NAc core injections of SCH 23390 on renewal of alcohol seeking after punishment-imposed abstinence. We found that both systemic and NAc shell and core injections of SCH 23390 decreased renewal of punished alcohol seeking. Our results demonstrate a critical role of NAc dopamine in renewal of alcohol seeking after punishment-imposed abstinence. We discuss these results in reference to the brain mechanisms of renewal of alcohol seeking after extinction versus punishment.

  8. International Union of Basic and Clinical Pharmacology. LXXIII. Nomenclature for the Formyl Peptide Receptor (FPR) Family

    PubMed Central

    YE, RICHARD D.; BOULAY, FRANÇOIS; WANG, JI MING; DAHLGREN, CLAES; GERARD, CRAIG; PARMENTIER, MARC; SERHAN, CHARLES N.; MURPHY, PHILIP M.

    2009-01-01

    Formyl peptide receptors (FPRs) are a small group of seven-transmembrane domain, G protein-coupled receptors that are expressed mainly by mammalian phagocytic leukocytes and are known to be important in host defense and inflammation. The three human FPRs (FPR1, FPR2/ALX, and FPR3) share significant sequence homology and are encoded by clustered genes. Collectively, these receptors bind an extraordinarily numerous and structurally diverse group of agonistic ligands, including N-formyl and nonformyl peptides of different composition, that chemoattract and activate phagocytes. N-formyl peptides, which are encoded in nature only by bacterial and mitochondrial genes and result from obligatory initiation of bacterial and mitochondrial protein synthesis with N-formylmethionine, is the only ligand class common to all three human receptors. Surprisingly, the endogenous anti-inflammatory peptide annexin 1 and its N-terminal fragments also bind human FPR1 and FPR2/ALX, and the anti-inflammatory eicosanoid lipoxin A4 is an agonist at FPR2/ALX. In comparison, fewer agonists have been identified for FPR3, the third member in this receptor family. Structural and functional studies of the FPRs have produced important information for understanding the general pharmacological principles governing all leukocyte chemoattractant receptors. This article aims to provide an overview of the discovery and pharmacological characterization of FPRs, to introduce an International Union of Basic and Clinical Pharmacology (IUPHAR)-recommended nomenclature, and to discuss unmet challenges, including the mechanisms used by these receptors to bind diverse ligands and mediate different biological functions. PMID:19498085

  9. Evolution of Spatially Coexpressed Families of Type-2 Vomeronasal Receptors in Rodents

    PubMed Central

    Francia, Simona; Silvotti, Lucia; Ghirardi, Filippo; Catzeflis, François; Percudani, Riccardo; Tirindelli, Roberto

    2015-01-01

    The vomeronasal organ (VNO) is an olfactory structure for the detection of pheromones. VNO neurons express three groups of unrelated G-protein-coupled receptors. Type-2 vomeronasal receptors (V2Rs) are specifically localized in the basal neurons of the VNO and are believed to sense protein pheromones eliciting specific reproductive behaviors. In murine species, V2Rs are organized into four families. Family-ABD V2Rs are expressed monogenically and coexpress with family-C V2Rs of either subfamily C1 (V2RC1) or subfamily C2 (V2RC2), according to a coordinate temporal diagram. Neurons expressing the phylogenetically ancient V2RC1 coexpress family-BD V2Rs or a specific group of subfamily-A V2Rs (V2RA8-10), whereas a second neuronal subset (V2RC2-positive) coexpresses a recently expanded group of five subfamily-A V2Rs (V2RA1-5) along with vomeronasal-specific Major Histocompatibility Complex molecules (H2-Mv). Through database mining and Sanger sequencing, we have analyzed the onset, diversification, and expansion of the V2R-families throughout the phylogeny of Rodentia. Our results suggest that the separation of V2RC1 and V2RC2 occurred in a Cricetidae ancestor in coincidence with the evolution of the H2-Mv genes; this phylogenetic event did not correspond with the origin of the coexpressing V2RA1-5 genes, which dates back to an ancestral myomorphan lineage. Interestingly, the evolution of receptors within the V2RA1-5 group may be implicated in the origin and diversification of some of the V2R putative cognate ligands, the exocrine secreting peptides. The establishment of V2RC2, which probably reflects the complex expansion and diversification of family-A V2Rs, generated receptors that have probably acquired a more subtle functional specificity. PMID:25539725

  10. Evolution of spatially coexpressed families of type-2 vomeronasal receptors in rodents.

    PubMed

    Francia, Simona; Silvotti, Lucia; Ghirardi, Filippo; Catzeflis, François; Percudani, Riccardo; Tirindelli, Roberto

    2015-01-01

    The vomeronasal organ (VNO) is an olfactory structure for the detection of pheromones. VNO neurons express three groups of unrelated G-protein-coupled receptors. Type-2 vomeronasal receptors (V2Rs) are specifically localized in the basal neurons of the VNO and are believed to sense protein pheromones eliciting specific reproductive behaviors. In murine species, V2Rs are organized into four families. Family-ABD V2Rs are expressed monogenically and coexpress with family-C V2Rs of either subfamily C1 (V2RC1) or subfamily C2 (V2RC2), according to a coordinate temporal diagram. Neurons expressing the phylogenetically ancient V2RC1 coexpress family-BD V2Rs or a specific group of subfamily-A V2Rs (V2RA8-10), whereas a second neuronal subset (V2RC2-positive) coexpresses a recently expanded group of five subfamily-A V2Rs (V2RA1-5) along with vomeronasal-specific Major Histocompatibility Complex molecules (H2-Mv). Through database mining and Sanger sequencing, we have analyzed the onset, diversification, and expansion of the V2R-families throughout the phylogeny of Rodentia. Our results suggest that the separation of V2RC1 and V2RC2 occurred in a Cricetidae ancestor in coincidence with the evolution of the H2-Mv genes; this phylogenetic event did not correspond with the origin of the coexpressing V2RA1-5 genes, which dates back to an ancestral myomorphan lineage. Interestingly, the evolution of receptors within the V2RA1-5 group may be implicated in the origin and diversification of some of the V2R putative cognate ligands, the exocrine secreting peptides. The establishment of V2RC2, which probably reflects the complex expansion and diversification of family-A V2Rs, generated receptors that have probably acquired a more subtle functional specificity. PMID:25539725

  11. Fscn1 is required for the trafficking of TGF-β family type I receptors during endoderm formation

    PubMed Central

    Liu, Zhaoting; Ning, Guozhu; Xu, Ranran; Cao, Yu; Meng, Anming; Wang, Qiang

    2016-01-01

    Microtubules function in TGF-β signalling by facilitating the cytoplasmic trafficking of internalized receptors and the nucleocytoplasmic shuttling of Smads. However, nothing is known about whether actin filaments are required for these processes. Here we report that zebrafish actin-bundling protein fscn1a is highly expressed in mesendodermal precursors and its expression is directly regulated by the TGF-β superfamily member Nodal. Knockdown or knockout of fscn1a leads to a reduction of Nodal signal transduction and endoderm formation in zebrafish embryos. Fscn1 specifically interacts with TGF-β family type I receptors, and its depletion disrupts the association between receptors and actin filaments and sequesters the internalized receptors into clathrin-coated vesicles. Therefore, Fscn1 acts as a molecular linker between TGF-β family type I receptors and the actin filaments to promote the trafficking of internalized receptors from clathrin-coated vesicles to early endosomes during zebrafish endoderm formation. PMID:27545838

  12. PLASTID MOVEMENT IMPAIRED1 mediates ABA sensitivity during germination and implicates ABA in light-mediated Chloroplast movements.

    PubMed

    Rojas-Pierce, Marcela; Whippo, Craig W; Davis, Phillip A; Hangarter, Roger P; Springer, Patricia S

    2014-10-01

    The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development, including seed development, germination and responses to water-deficit stress. A complex ABA signaling network integrates environmental signals including water availability and light intensity and quality to fine-tune the response to a changing environment. To further define the regulatory pathways that control water-deficit and ABA responses, we carried out a gene-trap tagging screen for water-deficit-regulated genes in Arabidopsis thaliana. This screen identified PLASTID MOVEMENT IMPAIRED1 (PMI1), a gene involved in blue-light-induced chloroplast movement, as functioning in ABA-response pathways. We provide evidence that PMI1 is involved in the regulation of seed germination by ABA, acting upstream of the intersection between ABA and low-glucose signaling pathways. Furthermore, PMI1 participates in the regulation of ABA accumulation during periods of water deficit at the seedling stage. The combined phenotypes of pmi1 mutants in chloroplast movement and ABA responses indicate that ABA signaling may modulate chloroplast motility. This result was further supported by the detection of altered chloroplast movements in the ABA mutants aba1-6, aba2-1 and abi1-1.

  13. A missense mutation in the second transmembrane segment of the luteinizing hormone receptor causes familial male-limited precocious puberty

    SciTech Connect

    Kraaij, R.; Post, M.; Grootegoed, J.A.

    1995-10-01

    Patients with familial male-limited precocious puberty present with early onset of puberty. Several missense mutations in the LH receptor gene that cause amino acid substitutions in the sixth transmembrane segment of the receptor protein have been shown to be a cause of the disorder. We have identified a novel LH receptor gene mutation in a patient with familial male-limited precocious puberty that results in a threonine for methionine substitution at position 398 in the second transmembrane segment of the receptor protein. In vitro expression in human embryonic kidney 293 cells of this LH receptor mutant and two previously described LH receptor mutants showed that cAMP production in the absence of hormone was elevated up to 25-fold compared to the basal level of the wild-type receptor. The ED{sub 50} values of hormone-induced cAMP production was relatively low for mutant receptors. We also produced receptors containing amino acid substitutions in both the second and sixth transmembrane segments. For these double mutants, basal receptor activities were similar to the basal activities observed in single mutants, whereas hormone-induced receptor activation was almost completely abolished. 31 refs., 2 figs.

  14. Expansion of a bitter taste receptor family in a polyphagous insect herbivore

    PubMed Central

    Xu, Wei; Papanicolaou, Alexie; Zhang, Hui-Jie; Anderson, Alisha

    2016-01-01

    The Insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. Gustatory receptors form the interface between the insect taste system and the environment. From genome and transcriptome sequencing we identified 197 novel gustatory receptor (GR) genes from the polyphagous pest Helicoverpa armigera. These GRs include a significantly expanded bitter receptor family (180 GRs) that could be further divided into three categories based on polypeptide lengths, gene structure and amino acid sequence. Type 1 includes 29 bitter Gr genes that possess introns. Type 2 includes 13 long intronless bitter Gr genes, while Type 3 comprises 131 short intronless bitter Gr genes. Calcium imaging analysis demonstrated that three Type 3 GRs (HarmGR35, HarmGR50 and HarmGR195) can be activated by a crude extract of cotton leaves. HarmGR195, a GR specifically and selectively expressed in adult tarsi, showed a specific response to proline, an amino acid widely present in plant tissues. We hypothesise that the expansion in the H. armigera GR family may be functionally tied to its polyphagous behavior. Understanding the molecular basis of polyphagy may provide opportunities for the development of new environmentally friendly pest control strategies. PMID:27032373

  15. Expansion of a bitter taste receptor family in a polyphagous insect herbivore.

    PubMed

    Xu, Wei; Papanicolaou, Alexie; Zhang, Hui-Jie; Anderson, Alisha

    2016-01-01

    The Insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. Gustatory receptors form the interface between the insect taste system and the environment. From genome and transcriptome sequencing we identified 197 novel gustatory receptor (GR) genes from the polyphagous pest Helicoverpa armigera. These GRs include a significantly expanded bitter receptor family (180 GRs) that could be further divided into three categories based on polypeptide lengths, gene structure and amino acid sequence. Type 1 includes 29 bitter Gr genes that possess introns. Type 2 includes 13 long intronless bitter Gr genes, while Type 3 comprises 131 short intronless bitter Gr genes. Calcium imaging analysis demonstrated that three Type 3 GRs (HarmGR35, HarmGR50 and HarmGR195) can be activated by a crude extract of cotton leaves. HarmGR195, a GR specifically and selectively expressed in adult tarsi, showed a specific response to proline, an amino acid widely present in plant tissues. We hypothesise that the expansion in the H. armigera GR family may be functionally tied to its polyphagous behavior. Understanding the molecular basis of polyphagy may provide opportunities for the development of new environmentally friendly pest control strategies. PMID:27032373

  16. Novel Small Molecule Activators of the Trk Family of Receptor Tyrosine Kinases

    PubMed Central

    Obianyo, Obiamaka; Ye, Keqiang

    2012-01-01

    The Tropomyosin-related kinase (Trk) receptors are a subset of the receptor tyrosine kinase family with an important functionality in the regulation of neurotrophic signaling in the peripheral and central nervous system. As the receptors are able to mediate neuronal survival by associating with their respective neurotrophin ligands, many studies have focused on the therapeutic potential of generating small-molecule mimetic compounds that elicit agonistic effects similar to those of the natural protein ligands. To this end, various structure-based studies have led to the generation of bivalent peptide-based agonists and antibodies that selectively initiate Trk receptor signaling; however, these compounds do not possess the ideal characteristics of a potential drug. Additionally, the reliance of structure-based data to generate the compound libraries, limits the potential identification of novel chemical structures with desirable activity. Therefore, subsequent investigations utilized a cell-based apoptotic screen to facilitate the analysis of large, diverse chemical libraries of small molecules and quickly identify compounds with Trk-dependent antiapoptotic activity. Herein, we describe the Trk agonists that have been identified by this screening methodology and summarize their in vitro and in vivo neurotrophic activity as well as their efficacy in various neurological disease models, implicating their future utility as therapeutic compounds. PMID:22982231

  17. Evolution of Parathyroid Hormone Receptor Family and Their Ligands in Vertebrate

    PubMed Central

    On, Jason S. W.; Chow, Billy K. C.; Lee, Leo T. O.

    2015-01-01

    The presence of the parathyroid hormones in vertebrates, including PTH, PTH-related peptide (PTHrP), and tuberoinfundibular peptide of 39 residues (TIP39), has been proposed to be the result of two rounds of whole genome duplication in the beginning of vertebrate diversification. Bioinformatics analyses, in particular chromosomal synteny study and the characterization of the PTH ligands and their receptors from various vertebrate species, provide evidence that strongly supports this hypothesis. In this mini-review, we summarize recent advances in studies regarding the molecular evolution and physiology of the PTH ligands and their receptors, with particular focus on non-mammalian vertebrates. In summary, the PTH family of peptides probably predates early vertebrate evolution, indicating a more ancient existence as well as a function of these peptides in invertebrates. PMID:25806022

  18. A transcriptional approach to unravel the connection between phospholipases A₂ and D and ABA signal in citrus under water stress.

    PubMed

    Romero, Paco; Lafuente, M Teresa; Alférez, Fernando

    2014-07-01

    The effect of water stress on the interplay between phospholipases (PL) A2 and D and ABA signalling was investigated in fruit and leaves from the sweet orange Navelate and its fruit-specific ABA-deficient mutant Pinalate by studying simultaneously expression of 5 PLD and 3 PLA2-encoding genes. In general, expression levels of PLD-encoding genes were higher at harvest in the flavedo (coloured outer part of the peel) from Pinalate. Moreover, a higher and transient increase in expression of CsPLDα, CsPLDβ, CsPLDδ and CsPLDζ was observed in the mutant as compared to Navelate fruit under water stress, which may reflect a mechanism of acclimation to water stress influenced by ABA deficiency. An early induction in CsPLDγ gene expression, when increase in peel damage during fruit storage was most evident, suggested a role for this gene in membrane degradation processes during water stress. Exogenous ABA on mutant fruit modified the expression of all PLD genes and reduced the expression of CsPLDα and CsPLDβ by 1 week to levels similar to those of Navelate, suggesting a repressor role of ABA on these genes. In general, CssPLA2α and β transcript levels were lower in flavedo from Pinalate than from Navelate fruit during the first 3 weeks of storage, suggesting that expression of these genes also depends at least partially on ABA levels. Patterns of expression of PLD and PLA2-encoding genes were very similar in Navelate and Pinalate leaves, which have similar ABA levels, when comparing both RH conditions. Results comparison with other from previous works in the same experimental systems helped to decipher the effect of the stress severity on the differential response of some of these genes under dehydration conditions and pointed out the interplay between PLA2 and PLD families and their connection with ABA signalling in citrus. PMID:24713122

  19. A transcriptional approach to unravel the connection between phospholipases A₂ and D and ABA signal in citrus under water stress.

    PubMed

    Romero, Paco; Lafuente, M Teresa; Alférez, Fernando

    2014-07-01

    The effect of water stress on the interplay between phospholipases (PL) A2 and D and ABA signalling was investigated in fruit and leaves from the sweet orange Navelate and its fruit-specific ABA-deficient mutant Pinalate by studying simultaneously expression of 5 PLD and 3 PLA2-encoding genes. In general, expression levels of PLD-encoding genes were higher at harvest in the flavedo (coloured outer part of the peel) from Pinalate. Moreover, a higher and transient increase in expression of CsPLDα, CsPLDβ, CsPLDδ and CsPLDζ was observed in the mutant as compared to Navelate fruit under water stress, which may reflect a mechanism of acclimation to water stress influenced by ABA deficiency. An early induction in CsPLDγ gene expression, when increase in peel damage during fruit storage was most evident, suggested a role for this gene in membrane degradation processes during water stress. Exogenous ABA on mutant fruit modified the expression of all PLD genes and reduced the expression of CsPLDα and CsPLDβ by 1 week to levels similar to those of Navelate, suggesting a repressor role of ABA on these genes. In general, CssPLA2α and β transcript levels were lower in flavedo from Pinalate than from Navelate fruit during the first 3 weeks of storage, suggesting that expression of these genes also depends at least partially on ABA levels. Patterns of expression of PLD and PLA2-encoding genes were very similar in Navelate and Pinalate leaves, which have similar ABA levels, when comparing both RH conditions. Results comparison with other from previous works in the same experimental systems helped to decipher the effect of the stress severity on the differential response of some of these genes under dehydration conditions and pointed out the interplay between PLA2 and PLD families and their connection with ABA signalling in citrus.

  20. Working memory span capacity improved by a D2 but not D1 receptor family agonist.

    PubMed

    Tarantino, Isadore S; Sharp, Richard F; Geyer, Mark A; Meves, Jessica M; Young, Jared W

    2011-06-01

    Patients with schizophrenia exhibit poor working memory (WM). Although several subcomponents of WM can be measured, evidence suggests the primary subcomponent affected in schizophrenia is span capacity (WMC). Indeed, the NIMH-funded MATRICS initiative recommended assaying the WMC when assessing the efficacy of a putative therapeutic for FDA approval. Although dopamine D1 receptor agonists improve delay-dependent memory in animals, evidence for improvements in WMC due to dopamine D1 receptor activation is limited. In contrast, the dopamine D2-family agonist bromocriptine improves WMC in humans. The radial arm maze (RAM) can be used to assess WMC, although complications due to ceiling effects or strategy confounds have limited its use. We describe a 12-arm RAM protocol designed to assess whether the dopamine D1-family agonist SKF 38393 (0, 1, 3, and 10 mg/kg) or bromocriptine (0, 1, 3, and 10 mg/kg) could improve WMC in C57BL/6N mice (n=12) in cross-over designs. WMC increased and strategy usage decreased with training. The dopamine D1 agonist SKF 38393 had no effect on WMC or long-term memory. Bromocriptine decreased WMC errors, without affecting long-term memory, consistent with human studies. These data confirm that WMC can be measured in mice and reveal drug effects that are consistent with reported effects in humans. Future research is warranted to identify the subtype of the D2-family of receptors responsible for the observed improvement in WMC. Finally, this RAM procedure may prove useful in developing animal models of deficient WMC to further assess putative treatments for the cognitive deficits in schizophrenia. PMID:21232557

  1. Signaling Lymphocytic Activation Molecule Family Receptor Homologs in New World Monkey Cytomegaloviruses

    PubMed Central

    Pérez-Carmona, Natàlia; Farré, Domènec; Martínez-Vicente, Pablo; Terhorst, Cox; Engel, Pablo

    2015-01-01

    ABSTRACT Throughout evolution, large DNA viruses have been usurping genes from their hosts to equip themselves with proteins that restrain host immune defenses. Signaling lymphocytic activation molecule (SLAM) family (SLAMF) receptors are involved in the regulation of both innate and adaptive immunity, which occurs upon engagement with their ligands via homotypic or heterotypic interactions. Here we report a total of seven SLAMF genes encoded by the genomes of two cytomegalovirus (CMV) species, squirrel monkey CMV (SMCMV) and owl monkey CMV (OMCMV), that infect New World monkeys. Our results indicate that host genes were captured by retrotranscription at different stages of the CMV-host coevolution. The most recent acquisition led to S1 in SMCMV. S1 is a SLAMF6 homolog with an amino acid sequence identity of 97% to SLAMF6 in its ligand-binding N-terminal Ig domain. We demonstrate that S1 is a cell surface glycoprotein capable of binding to host SLAMF6. Furthermore, the OMCMV genome encodes A33, an LY9 (SLAMF3) homolog, and A43, a CD48 (SLAMF2) homolog, two soluble glycoproteins which recognize their respective cellular counterreceptors and thus are likely to be viral SLAMF decoy receptors. In addition, distinct copies of further divergent CD48 homologs were found to be encoded by both CMV genomes. Remarkably, all these molecules display a number of unique features, including cytoplasmic tails lacking characteristic SLAMF signaling motifs. Taken together, our findings indicate a novel immune evasion mechanism in which incorporation of host SLAMF receptors that retain their ligand-binding properties enables viruses to interfere with SLAMF functions and to supply themselves with convenient structural molds for expanding their immunomodulatory repertoires. IMPORTANCE The way in which viruses shape their genomes under the continual selective pressure exerted by the host immune system is central for their survival. Here, we report that New World monkey cytomegaloviruses

  2. The TAM family: phosphatidylserine sensing receptor tyrosine kinases gone awry in cancer.

    PubMed

    Graham, Douglas K; DeRyckere, Deborah; Davies, Kurtis D; Earp, H Shelton

    2014-12-01

    The TYRO3, AXL (also known as UFO) and MERTK (TAM) family of receptor tyrosine kinases (RTKs) are aberrantly expressed in multiple haematological and epithelial malignancies. Rather than functioning as oncogenic drivers, their induction in tumour cells predominately promotes survival, chemoresistance and motility. The unique mode of maximal activation of this RTK family requires an extracellular lipid–protein complex. For example, the protein ligand, growth arrest-specific protein 6 (GAS6), binds to phosphatidylserine (PtdSer) that is externalized on apoptotic cell membranes, which activates MERTK on macrophages. This triggers engulfment of apoptotic material and subsequent anti-inflammatory macrophage polarization. In tumours, autocrine and paracrine ligands and apoptotic cells are abundant, which provide a survival signal to the tumour cell and favour an anti-inflammatory, immunosuppressive microenvironment. Thus, TAM kinase inhibition could stimulate antitumour immunity, reduce tumour cell survival, enhance chemosensitivity and diminish metastatic potential. PMID:25568918

  3. The TAM family: phosphatidylserine sensing receptor tyrosine kinases gone awry in cancer.

    PubMed

    Graham, Douglas K; DeRyckere, Deborah; Davies, Kurtis D; Earp, H Shelton

    2014-12-01

    The TYRO3, AXL (also known as UFO) and MERTK (TAM) family of receptor tyrosine kinases (RTKs) are aberrantly expressed in multiple haematological and epithelial malignancies. Rather than functioning as oncogenic drivers, their induction in tumour cells predominately promotes survival, chemoresistance and motility. The unique mode of maximal activation of this RTK family requires an extracellular lipid–protein complex. For example, the protein ligand, growth arrest-specific protein 6 (GAS6), binds to phosphatidylserine (PtdSer) that is externalized on apoptotic cell membranes, which activates MERTK on macrophages. This triggers engulfment of apoptotic material and subsequent anti-inflammatory macrophage polarization. In tumours, autocrine and paracrine ligands and apoptotic cells are abundant, which provide a survival signal to the tumour cell and favour an anti-inflammatory, immunosuppressive microenvironment. Thus, TAM kinase inhibition could stimulate antitumour immunity, reduce tumour cell survival, enhance chemosensitivity and diminish metastatic potential.

  4. Structure of 5-hydroxymethylcytosine-specific restriction enzyme, AbaSI, in complex with DNA

    SciTech Connect

    Horton, John R.; Borgaro, Janine G.; Griggs, Rose M.; Quimby, Aine; Guan, Shengxi; Zhang, Xing; Wilson, Geoffrey G.; Zheng, Yu; Zhu, Zhenyu; Cheng, Xiaodong

    2014-07-03

    AbaSI, a member of the PvuRts1I-family of modification-dependent restriction endonucleases, cleaves DNA containing 5-hydroxymethylctosine (5hmC) and glucosylated 5hmC (g5hmC), but not DNA containing unmodified cytosine. AbaSI has been used as a tool for mapping the genomic locations of 5hmC, an important epigenetic modification in the DNA of higher organisms. Here we report the crystal structures of AbaSI in the presence and absence of DNA. These structures provide considerable, although incomplete, insight into how this enzyme acts. AbaSI appears to be mainly a homodimer in solution, but interacts with DNA in our structures as a homotetramer. Each AbaSI subunit comprises an N-terminal, Vsr-like, cleavage domain containing a single catalytic site, and a C-terminal, SRA-like, 5hmC-binding domain. Two N-terminal helices mediate most of the homodimer interface. Dimerization brings together the two catalytic sites required for double-strand cleavage, and separates the 5hmC binding-domains by ~ 70 Å, consistent with the known activity of AbaSI which cleaves DNA optimally between symmetrically modified cytosines ~ 22 bp apart. The eukaryotic SET and RING-associated (SRA) domains bind to DNA containing 5-methylcytosine (5mC) in the hemi-methylated CpG sequence. They make contacts in both the major and minor DNA grooves, and flip the modified cytosine out of the helix into a conserved binding pocket. In contrast, the SRA-like domain of AbaSI, which has no sequence specificity, contacts only the minor DNA groove, and in our current structures the 5hmC remains intra-helical. A conserved, binding pocket is nevertheless present in this domain, suitable for accommodating 5hmC and g5hmC. We consider it likely, therefore, that base-flipping is part of the recognition and cleavage mechanism of AbaSI, but that our structures represent an earlier, pre-flipped stage, prior to actual recognition.

  5. Biological effects of insulin and its analogs on cancer cells with different insulin family receptor expression.

    PubMed

    Sciacca, Laura; Cassarino, Maria Francesca; Genua, Marco; Vigneri, Paolo; Giovanna Pennisi, Maria; Malandrino, Pasqualino; Squatrito, Sebastiano; Pezzino, Vincenzo; Vigneri, Riccardo

    2014-11-01

    Hyperinsulinemia is a likely cause of the increased cancer incidence and mortality in diabetic patients, but its role is difficult to define in vivo. Previous in vitro studies testing the mitogenic potential of insulin and its analogs provided incomplete and sometimes contradictory results. To better evaluate cancer cell responsiveness to insulin, to its analogs and to IGF-I, we measured under identical experimental conditions cell proliferation, invasiveness, and foci formation in six cancer cell lines with different insulin receptor family expression levels. The cancer cells studied have a different expression of insulin receptor (IR), its isoforms (IR-A and IR-B), and of the IGF-I receptor. The data indicate that insulin stimulates proliferation in all cancer cell lines, invasiveness in some, and foci formation in none. Cancer cell responses to insulin (and IGF-I) are not related to receptor expression levels; moreover, hormone-stimulated proliferation and invasiveness are not correlated. IGF-I is a more potent stimulator than insulin in most but not all cancer cell lines. Insulin analogs including M1 and M2 Glargine metabolites stimulate cancer cells similar to insulin. However, exceptions occur for specific analogs in particular cancer cells. In conclusion, in vitro insulin is an effective growth factor for all cancer cells but the biological response to insulin cannot be predicted on the basis of receptor expression levels. In the clinical setting, these observations should be taken in account when deciding treatment for diabetic patients who are at risk of undiscovered cancer or survivors of oncological diseases.

  6. Mutational analysis of the androgen receptor gene in two Chinese families with complete androgen insensitivity syndrome

    PubMed Central

    WANG, SONG; XU, HAIKUN; AN, WEI; ZHU, DECHUN; LI, DEJUN

    2016-01-01

    Androgens are essential for normal male sex differentiation and are responsible for the normal development of male secondary sexual characteristics at puberty. The physiological effects of androgens are mediated by the androgen receptor (AR). Mutations in the AR gene are the most common cause of androgen insensitivity syndrome. The present study undertook a genetic analysis of the AR gene in two unrelated families affected by complete androgen insensitivity syndrome (CAIS) in China. In family 1, a previously reported nonsense mutation (G-to-A; p.W751X) was identified in exon 5 of the AR gene. In addition, a novel missense mutation was detected in exon 6 of the AR gene from family 2; this mutation resulted in a predicted amino acid change from phenylalanine to serine at codon 804 (T-to-C; p.F804S) in the ligand-binding domain (LBD) of AR. Computer simulation of the structural changes generated by the p.F804S substitution revealed marked conformational alterations in the hydrophobic core responsible for the stability and function of the AR-LBD. In conclusion, the present study identified two mutations from two unrelated Chinese families affected by CAIS. The novel mutation (p.F804S) may provide insights into the molecular mechanism underlying CAIS. Furthermore, it expands on the number of mutational hot spots in the international AR mutation database, which may be useful in the future for prenatal diagnosis and genetic counseling. PMID:27284311

  7. Evolution of T cell receptor genes. Extensive diversity of V beta families in the Mexican axolotl.

    PubMed

    Fellah, J S; Kerfourn, F; Charlemagne, J

    1994-11-15

    We have cloned 36 different rearranged variable regions (V beta) genes encoding the beta-chain of the T cell receptor in an amphibian species, Ambystoma mexicanum (the Mexican axolotl). Eleven different V beta segments were identified, which can be classified into 9 families on the basis of a minimum of 75% nucleotide identity. All the cloned V beta segments have the canonical features of known mammalian and avian V beta, including conserved residues Cys23, Trp34, Arg69, Tyr90, and Cys92. There seems to be a greater genetic distance between the axolotl V beta families than between the different V beta families of any mammalian species examined to date: most of the axolotl V beta s have fewer than 35% identical nucleotides and the less related families (V beta 4 and V beta 8) have no more than 23.2% identity (13.5% at the amino acid level). Despite their great mutual divergence, several axolotl V beta are sequence-related to some mammalian V beta genes, like the human V beta 13 and V beta 20 segments and their murine V beta 8 and V beta 14 homologues. However, the axolotl V beta 8 and V beta 9 families are not significantly related to any other V beta sequence at the nucleotide level and show limited amino acid similarity to mammalian V alpha, V kappa III, or VH sequences. The detection of nine V beta families among 35 randomly cloned V beta segments suggests that the V beta gene repertoire in the axolotl is probably larger than presently estimated. PMID:7963525

  8. Abscisic acid (ABA) regulation of Arabidopsis SR protein gene expression.

    PubMed

    Cruz, Tiago M D; Carvalho, Raquel F; Richardson, Dale N; Duque, Paula

    2014-01-01

    Serine/arginine-rich (SR) proteins are major modulators of alternative splicing, a key generator of proteomic diversity and flexible means of regulating gene expression likely to be crucial in plant environmental responses. Indeed, mounting evidence implicates splicing factors in signal transduction of the abscisic acid (ABA) phytohormone, which plays pivotal roles in the response to various abiotic stresses. Using real-time RT-qPCR, we analyzed total steady-state transcript levels of the 18 SR and two SR-like genes from Arabidopsis thaliana in seedlings treated with ABA and in genetic backgrounds with altered expression of the ABA-biosynthesis ABA2 and the ABA-signaling ABI1 and ABI4 genes. We also searched for ABA-responsive cis elements in the upstream regions of the 20 genes. We found that members of the plant-specific SC35-Like (SCL) Arabidopsis SR protein subfamily are distinctively responsive to exogenous ABA, while the expression of seven SR and SR-related genes is affected by alterations in key components of the ABA pathway. Finally, despite pervasiveness of established ABA-responsive promoter elements in Arabidopsis SR and SR-like genes, their expression is likely governed by additional, yet unidentified cis-acting elements. Overall, this study pinpoints SR34, SR34b, SCL30a, SCL28, SCL33, RS40, SR45 and SR45a as promising candidates for involvement in ABA-mediated stress responses. PMID:25268622

  9. Abscisic Acid (ABA) Regulation of Arabidopsis SR Protein Gene Expression

    PubMed Central

    Cruz, Tiago M. D.; Carvalho, Raquel F.; Richardson, Dale N.; Duque, Paula

    2014-01-01

    Serine/arginine-rich (SR) proteins are major modulators of alternative splicing, a key generator of proteomic diversity and flexible means of regulating gene expression likely to be crucial in plant environmental responses. Indeed, mounting evidence implicates splicing factors in signal transduction of the abscisic acid (ABA) phytohormone, which plays pivotal roles in the response to various abiotic stresses. Using real-time RT-qPCR, we analyzed total steady-state transcript levels of the 18 SR and two SR-like genes from Arabidopsis thaliana in seedlings treated with ABA and in genetic backgrounds with altered expression of the ABA-biosynthesis ABA2 and the ABA-signaling ABI1 and ABI4 genes. We also searched for ABA-responsive cis elements in the upstream regions of the 20 genes. We found that members of the plant-specific SC35-Like (SCL) Arabidopsis SR protein subfamily are distinctively responsive to exogenous ABA, while the expression of seven SR and SR-related genes is affected by alterations in key components of the ABA pathway. Finally, despite pervasiveness of established ABA-responsive promoter elements in Arabidopsis SR and SR-like genes, their expression is likely governed by additional, yet unidentified cis-acting elements. Overall, this study pinpoints SR34, SR34b, SCL30a, SCL28, SCL33, RS40, SR45 and SR45a as promising candidates for involvement in ABA-mediated stress responses. PMID:25268622

  10. EIN4 and ERS2 are members of the putative ethylene receptor gene family in Arabidopsis.

    PubMed Central

    Hua, J; Sakai, H; Nourizadeh, S; Chen, Q G; Bleecker, A B; Ecker, J R; Meyerowitz, E M

    1998-01-01

    The Arabidopsis ethylene receptor gene ETR1 and two related genes, ERS1 and ETR2, were identified previously. These three genes encode proteins homologous to the two-component regulators that are widely used for environment sensing in bacteria. Mutations in these genes confer ethylene insensitivity to wild-type plants. Here, we identified two Arabidopsis genes, EIN4 and ERS2, by cross-hybridizing them with ETR2. Sequence analysis showed that they are more closely related to ETR2 than they are to ETR1 or ERS1. EIN4 previously was isolated as a dominant ethylene-insensitive mutant. ERS2 also conferred dominant ethylene insensitivity when certain mutations were introduced into it. Double mutant analysis indicated that ERS2, similar to ETR1, ETR2, ERS1, and EIN4, acts upstream of CTR1. Therefore, EIN4 and ERS2, along with ETR1, ETR2, and ERS1, are members of the ethylene receptor-related gene family of Arabidopsis. RNA expression patterns of members of this gene family suggest that they might have distinct as well as redundant functions in ethylene perception. PMID:9707532

  11. The syndecan family of proteoglycans. Novel receptors mediating internalization of atherogenic lipoproteins in vitro.

    PubMed Central

    Fuki, I V; Kuhn, K M; Lomazov, I R; Rothman, V L; Tuszynski, G P; Iozzo, R V; Swenson, T L; Fisher, E A; Williams, K J

    1997-01-01

    Cell-surface heparan sulfate proteoglycans have been shown to participate in lipoprotein catabolism, but the roles of specific proteoglycan classes have not been examined previously. Here, we studied the involvement of the syndecan proteoglycan family. First, transfection of CHO cells with expression vectors for several syndecan core proteins produced parallel increases in the cell association and degradation of lipoproteins enriched in lipoprotein lipase, a heparan-binding protein. Second, a chimeric construct, FcR-Synd1, that consists of the ectodomain of the IgG Fc receptor Ia linked to the highly conserved transmembrane and cytoplasmic domains of syndecan-1 directly mediated efficient internalization, in a process triggered by ligand clustering. Third, internalization of lipase-enriched lipoproteins via syndecan-1 and of clustered IgGs via the chimera showed identical kinetics (t1/2 = 1 h) and identical dose-response sensitivities to cytochalasin B, which disrupts microfilaments, and to genistein, which inhibits tyrosine kinases. In contrast, internalization of the receptor-associated protein, which proceeds via coated pits, showed a t1/2 < 15 min, limited sensitivity to cytochalasin B, and complete insensitivity to genistein. Thus, syndecan proteoglycans can directly mediate ligand catabolism through a pathway with characteristics distinct from coated pits, and might act as receptors for atherogenic lipoproteins and other ligands in vivo. PMID:9294130

  12. Differential Expression of Two Novel Members of the Tomato Ethylene-Receptor Family

    PubMed Central

    Tieman, Denise M.; Klee, Harry J.

    1999-01-01

    The phytohormone ethylene regulates many aspects of plant growth, development, and environmental responses. Much of the developmental regulation of ethylene responses in tomato (Lycopersicon esculentum) occurs at the level of hormone sensitivity. In an effort to understand the regulation of ethylene responses, we isolated and characterized tomato genes with sequence similarity to the Arabidopsis ETR1 (ethylene response 1) ethylene receptor. Previously, we isolated three genes that exhibit high similarity to ETR1 and to each other. Here we report the isolation of two additional genes, LeETR4 and LeETR5, that are only 42% and 40% identical to ETR1, respectively. Although the amino acids known to be involved in ethylene binding are conserved, LeETR5 lacks the histidine within the kinase domain that is predicted to be phosphorylated. This suggests that histidine kinase activity is not necessary for an ethylene response, because mutated forms of both LeETR4 and LeETR5 confer dominant ethylene insensitivity in transgenic Arabidopsis plants. Expression analysis indicates that LeETR4 accounts for most of the putative ethylene-receptor mRNA present in reproductive tissues, but, like LeETR5, it is less abundant in vegetative tissues. Taken together, ethylene perception in tomato is potentially quite complex, with at least five structurally divergent, putative receptor family members exhibiting significant variation in expression levels throughout development. PMID:10318694

  13. Cross-talk between the NR3B and NR4A families of orphan nuclear receptors

    SciTech Connect

    Lammi, Johanna; Rajalin, Ann-Marie; Huppunen, Johanna; Aarnisalo, Piia . E-mail: piia.aarnisalo@helsinki.fi

    2007-07-27

    Estrogen-related receptors (NR3B family) and Nurr1, NGFI-B, and Nor1 (NR4A family) are orphan nuclear receptors lacking identified natural ligands. The mechanisms regulating their transcriptional activities have remained elusive. We have previously observed that the members of NR3B and NR4A families are coexpressed in certain cell types such as osteoblasts and that the ability of Nurr1 to transactivate the osteopontin promoter is repressed by ERRs. We have now studied the cross-talk between NR3B and NR4A receptors. We show that NR3B and NR4A receptors mutually repress each others' transcriptional activity. The repression involves intact DNA-binding domains and dimerization interfaces but does not result from competition for DNA binding or from heterodimerization. The activation functions of NR3B and NR4A receptors are dispensable for the cross-talk. In conclusion, we report that cross-talk between NR3B and NR4A receptors is a mechanism modulating the transcriptional activities of these orphan nuclear receptors.

  14. The B7 family of immunoregulatory receptors: A comparative and evolutionary perspective

    USGS Publications Warehouse

    Hansen, J.D.; Pasquier, L.D.; Lefranc, M.-P.; Lopez, V.; Benmansour, A.; Boudinot, P.

    2009-01-01

    In mammals, T cell activation requires specific recognition of the peptide-MHC complex by the TcR and co-stimulatory signals. Important co-stimulatory receptors expressed by T cells are the molecules of the CD28 family, that regulate T cell activation, proliferation and tolerance. These receptors recognize B7s and B7-homologous (B7H) molecules that are typically expressed by the antigen presenting cells. In teleost fish, typical T cell responses have been described and the TcR, MHC and CD28/CTLA4 genes have been characterized. In contrast, the members of the B7 gene family have only been described in mammals and birds and have yet to be addressed in lower vertebrates. To learn more about the evolution of components guiding T cell activation in vertebrates, we performed a systematic genomic survey for the B7 co-stimulatory and co-inhibitory IgSF receptors in lower vertebrates with an emphasis on teleost fish. Our search identified fish sequences that are orthologous to B7, B7-H1/B7-DC, B7-H3 and B7-H4 as defined by sequence identity, phylogeny and combinations of short or long-range syntenic relationships. However, we were unable to identify clear orthologs for B7-H2 (CD275, ICOS ligand) in bony fish, which correlates with our prior inability to find ICOS in fish. Interestingly, our results indicate that teleost fish possess a single B7.1/B7.2 (CD80/86) molecule that likely interacts with CD28/CTLA4 as the ligand-binding regions seem to be conserved in both partners. Overall, our analyses implies that gene duplication (and loss) have shaped a molecular repertoire of B7-like molecules that was recruited for the refinement of T cell activation during the evolution of the vertebrates.

  15. The Functional Role of the T1R Family of Receptors in Sweet Taste and Feeding

    PubMed Central

    Treesukosol, Yada; Smith, Kimberly R.; Spector, Alan C.

    2011-01-01

    The discovery of the T1R family of Class C G protein-coupled receptors in the peripheral gustatory system a decade ago has been a tremendous advance for taste research, and its conceptual reach has extended to other organ systems. There are three proteins in the family, T1R1, T1R2, and T1R3, encoded by their respective genes, Tas1r1, Tas1r2, and Tas1r3. T1R2 combines with T1R3 to form a heterodimer that binds with sugars and other sweeteners. T1R3 also combines with T1R1 to form a heterodimer that binds with L-amino acids. These proteins are expressed not only in taste bud cells, but one or more of these T1Rs have also been identified in the nasal epithelium, gut, pancreas, liver, kidney, testes and brain in various mammalian species. Here we review current perspectives regarding the functional role of these receptors, concentrating on sweet taste and feeding. We also discuss behavioral findings suggesting that a glucose polymer mixture, Polycose, which rodents avidly prefer, appears to activate a receptor that does not depend on the combined expression of T1R2 and T1R3. In addition, although the T1Rs have been implicated as playing a role in glucose sensing, T1R2 knock-out (KO) and T1R3 KO mice display normal chow and fluid intake as well as normal body weight compared with same-sex littermate wild type (WT) controls. Moreover, regardless of whether they are fasted or not, these KO mice do not differ from their WT counterparts in their Polycose intake across a broad range of concentrations in 30-min intake tests. The functional implications of these results and those in the literature are considered. PMID:21376068

  16. The nicotinic acetylcholine receptor gene family of the honey bee, Apis mellifera.

    PubMed

    Jones, Andrew K; Raymond-Delpech, Valerie; Thany, Steeve H; Gauthier, Monique; Sattelle, David B

    2006-11-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission and play roles in many cognitive processes. They are under intense research as potential targets of drugs used to treat neurodegenerative diseases and neurological disorders such as Alzheimer's disease and schizophrenia. Invertebrate nAChRs are targets of anthelmintics as well as a major group of insecticides, the neonicotinoids. The honey bee, Apis mellifera, is one of the most beneficial insects worldwide, playing an important role in crop pollination, and is also a valuable model system for studies on social interaction, sensory processing, learning, and memory. We have used the A. mellifera genome information to characterize the complete honey bee nAChR gene family. Comparison with the fruit fly Drosophila melanogaster and the malaria mosquito Anopheles gambiae shows that the honey bee possesses the largest family of insect nAChR subunits to date (11 members). As with Drosophila and Anopheles, alternative splicing of conserved exons increases receptor diversity. Also, we show that in one honey bee nAChR subunit, six adenosine residues are targeted for RNA A-to-I editing, two of which are evolutionarily conserved in Drosophila melanogaster and Heliothis virescens orthologs, and that the extent of editing increases as the honey bee lifecycle progresses, serving to maximize receptor diversity at the adult stage. These findings on Apis mellifera enhance our understanding of nAChR functional genomics and provide a useful basis for the development of improved insecticides that spare a major beneficial insect species.

  17. Abscisic acid (ABA) regulates grape bud dormancy, and dormancy release stimuli may act through modification of ABA metabolism

    PubMed Central

    Zheng, Chuanlin; Halaly, Tamar; Acheampong, Atiako Kwame; Takebayashi, Yumiko; Jikumaru, Yusuke; Kamiya, Yuji; Or, Etti

    2015-01-01

    In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8’OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Interestingly, an inhibitor of ethylene signalling attenuated these effects of HC on ABA metabolism. HC also modulated the expression of ABA signalling regulators, in a manner that supports a decreased ABA level and response. Taken together, the data support HC-induced removal of ABA-mediated repression via regulation of ABA metabolism and signalling. Expression profiling during the natural dormancy cycle revealed that at maximal dormancy, the HC-regulated VvNCED1 transcript level starts to drop. In parallel, levels of VvA8H-CYP707A4 transcript and ABA catabolites increase sharply. This may provide initial support for the involvement of ABA metabolism also in the execution of natural dormancy. PMID:25560179

  18. Abscisic acid (ABA) regulates grape bud dormancy, and dormancy release stimuli may act through modification of ABA metabolism.

    PubMed

    Zheng, Chuanlin; Halaly, Tamar; Acheampong, Atiako Kwame; Takebayashi, Yumiko; Jikumaru, Yusuke; Kamiya, Yuji; Or, Etti

    2015-03-01

    In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8'OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Interestingly, an inhibitor of ethylene signalling attenuated these effects of HC on ABA metabolism. HC also modulated the expression of ABA signalling regulators, in a manner that supports a decreased ABA level and response. Taken together, the data support HC-induced removal of ABA-mediated repression via regulation of ABA metabolism and signalling. Expression profiling during the natural dormancy cycle revealed that at maximal dormancy, the HC-regulated VvNCED1 transcript level starts to drop. In parallel, levels of VvA8H-CYP707A4 transcript and ABA catabolites increase sharply. This may provide initial support for the involvement of ABA metabolism also in the execution of natural dormancy.

  19. The Heat Stress Factor HSFA6b Connects ABA Signaling and ABA-Mediated Heat Responses1[OPEN

    PubMed Central

    Yang, Chen-Ru

    2016-01-01

    Heat stress response (HSR) is a conserved mechanism developed to increase the expression of heat shock proteins (HSPs) via a heat shock factor (HSF)-dependent mechanism. Signaling by the stress phytohormone abscisic acid (ABA) is involved in acquired thermotolerance as well. Analysis of Arabidopsis (Arabidopsis thaliana) microarray databases revealed that the expression of HSFA6b, a class A HSF, extensively increased with salinity, osmotic, and cold stresses, but not heat. Here, we show that HSFA6b plays a pivotal role in the response to ABA and in thermotolerance. Salt-inducible HSFA6b expression was down-regulated in ABA-insensitive and -deficient mutants; however, exogenous ABA application restored expression in ABA-deficient, but not -insensitive plants. Thus, ABA signaling is required for proper HSFA6b expression. A transcriptional activation assay of protoplasts revealed that ABA treatment and coexpression of an ABA signaling master effector, ABA-RESPONSIVE ELEMENT-BINDING PROTEIN1, could activate the HSFA6b promoter. In addition, HSFA6b directly bound to the promoter of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN2A and enhanced its expression. Analysis of ABA responses in seed germination, cotyledon greening, and root growth as well as salt and drought tolerance in HSFA6b-null, overexpression, and dominant negative mutants revealed that HSFA6b is a positive regulator participating in ABA-mediated salt and drought resistance. Thermoprotection tests showed that HSFA6b was required for thermotolerance acquisition. Our study reveals a network in which HSFA6b operates as a downstream regulator of the ABA-mediated stress response and is required for heat stress resistance. This new ABA-signaling pathway is integrated into the complex HSR network in planta. PMID:27493213

  20. Research Resource: Tissue- and Pathway-Specific Metabolomic Profiles of the Steroid Receptor Coactivator (SRC) Family

    PubMed Central

    York, Brian; Sagen, Jørn V.; Tsimelzon, Anna; Louet, Jean-Francios; Chopra, Atul R.; Reineke, Erin L.; Zhou, Suoling; Stevens, Robert D.; Wenner, Brett R.; Ilkayeva, Olga; Bain, James R.; Xu, Jianming; Hilsenbeck, Susan G.; Newgard, Christopher B.

    2013-01-01

    The rapidly growing family of transcriptional coregulators includes coactivators that promote transcription and corepressors that harbor the opposing function. In recent years, coregulators have emerged as important regulators of metabolic homeostasis, including the p160 steroid receptor coactivator (SRC) family. Members of the SRC family have been ascribed important roles in control of gluconeogenesis, fat absorption and storage in the liver, and fatty acid oxidation in skeletal muscle. To provide a deeper and more granular understanding of the metabolic impact of the SRC family members, we performed targeted metabolomic analyses of key metabolic byproducts of glucose, fatty acid, and amino acid metabolism in mice with global knockouts (KOs) of SRC-1, SRC-2, or SRC-3. We measured amino acids, acyl carnitines, and organic acids in five tissues with key metabolic functions (liver, heart, skeletal muscle, brain, plasma) isolated from SRC-1, -2, or -3 KO mice and their wild-type littermates under fed and fasted conditions, thereby unveiling unique metabolic functions of each SRC. Specifically, SRC-1 ablation revealed the most significant impact on hepatic metabolism, whereas SRC-2 appeared to impact cardiac metabolism. Conversely, ablation of SRC-3 primarily affected brain and skeletal muscle metabolism. Surprisingly, we identified very few metabolites that changed universally across the three SRC KO models. The findings of this Research Resource demonstrate that coactivator function has very limited metabolic redundancy even within the homologous SRC family. Furthermore, this work also demonstrates the use of metabolomics as a means for identifying novel metabolic regulatory functions of transcriptional coregulators. PMID:23315938

  1. The Mg-Chelatase H Subunit of Arabidopsis Antagonizes a Group of WRKY Transcription Repressors to Relieve ABA-Responsive Genes of Inhibition[W][OA

    PubMed Central

    Shang, Yi; Yan, Lu; Liu, Zhi-Qiang; Cao, Zheng; Mei, Chao; Xin, Qi; Wu, Fu-Qing; Wang, Xiao-Fang; Du, Shu-Yuan; Jiang, Tao; Zhang, Xiao-Feng; Zhao, Rui; Sun, Hai-Li; Liu, Rui; Yu, Yong-Tao; Zhang, Da-Peng

    2010-01-01

    The phytohormone abscisic acid (ABA) plays a vital role in plant development and response to environmental challenges, but the complex networks of ABA signaling pathways are poorly understood. We previously reported that a chloroplast protein, the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR), functions as a receptor for ABA in Arabidopsis thaliana. Here, we report that ABAR spans the chloroplast envelope and that the cytosolic C terminus of ABAR interacts with a group of WRKY transcription factors (WRKY40, WRKY18, and WRKY60) that function as negative regulators of ABA signaling in seed germination and postgermination growth. WRKY40, a central negative regulator, inhibits expression of ABA-responsive genes, such as ABI5. In response to a high level of ABA signal that recruits WRKY40 from the nucleus to the cytosol and promotes ABAR–WRKY40 interaction, ABAR relieves the ABI5 gene of inhibition by repressing WRKY40 expression. These findings describe a unique ABA signaling pathway from the early signaling events to downstream gene expression. PMID:20543028

  2. Role of ErbB family receptor tyrosine kinases in intrahepatic cholangiocarcinoma

    PubMed Central

    Sirica, Alphonse E

    2008-01-01

    Aberrant expression and signaling of epidermal growth factor receptor (ErbB) family receptor tyrosine kinases, most notably that of ErbB2 and ErbB1, have been implicated in the molecular pathogenesis of intrahepatic cholangiocarcinoma. Constitutive overexpression of ErbB2 and/or ErbB1 in malignant cholangiocytes has raised interest in the possibility that agents which selectively target these receptors could potentially be effective in cholangiocarcinoma therapy. However, current experience with such ErbB-directed therapies have at best produced only modest responses in patients with biliary tract cancers. This review provides a comprehensive and critical analysis of both preclinical and clinical studies aimed at assessing the role of altered ErbB2 and/or ErbB1 expression, genetic modifications, and dysregulated signaling on cholangiocarcinoma development and progression. Specific limitations in experimental approaches that have been used to assess human cholangiocarcinoma specimens for ErbB2 and/or ErbB1 overexpression and gene amplification are discussed. In addition, current rodent models of intrahepatic cholangiocarcinogenesis associated with constitutive ErbB2 overexpression are reviewed. Select interactive relationships between ErbB2 or ErbB1 with other relevant molecular signaling pathways associated with intrahepatic cholangiocarcinoma development and progression are also detailed, including those linking ErbB receptors to bile acid, cyclooxygenase-2, interleukin-6/gp130, transmembrane mucins, hepatocyte growth factor/Met, and vascular endothelial growth factor signaling. Lastly, various factors that can limit therapeutic efficacy of ErbB-targeted agents against cholangiocarcinoma are considered. PMID:19084911

  3. International Union of Basic and Clinical Pharmacology. [corrected]. LXXXIX. Update on the extended family of chemokine receptors and introducing a new nomenclature for atypical chemokine receptors.

    PubMed

    Bachelerie, Francoise; Ben-Baruch, Adit; Burkhardt, Amanda M; Combadiere, Christophe; Farber, Joshua M; Graham, Gerard J; Horuk, Richard; Sparre-Ulrich, Alexander Hovard; Locati, Massimo; Luster, Andrew D; Mantovani, Alberto; Matsushima, Kouji; Murphy, Philip M; Nibbs, Robert; Nomiyama, Hisayuki; Power, Christine A; Proudfoot, Amanda E I; Rosenkilde, Mette M; Rot, Antal; Sozzani, Silvano; Thelen, Marcus; Yoshie, Osamu; Zlotnik, Albert

    2014-01-01

    Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145-176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human Genome

  4. International Union of Pharmacology. LXXXIX. Update on the Extended Family of Chemokine Receptors and Introducing a New Nomenclature for Atypical Chemokine Receptors

    PubMed Central

    Bachelerie, Francoise; Ben-Baruch, Adit; Burkhardt, Amanda M.; Combadiere, Christophe; Farber, Joshua M.; Graham, Gerard J.; Horuk, Richard; Sparre-Ulrich, Alexander Hovard; Locati, Massimo; Luster, Andrew D.; Mantovani, Alberto; Matsushima, Kouji; Nibbs, Robert; Nomiyama, Hisayuki; Power, Christine A.; Proudfoot, Amanda E. I.; Rosenkilde, Mette M.; Rot, Antal; Sozzani, Silvano; Thelen, Marcus; Yoshie, Osamu; Zlotnik, Albert

    2014-01-01

    Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145–176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human

  5. Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism.

    PubMed

    Sartorato, Paola; Lapeyraque, Anne-Laure; Armanini, Decio; Kuhnle, Ursula; Khaldi, Yasmina; Salomon, Rémi; Abadie, Véronique; Di Battista, Eliana; Naselli, Arturo; Racine, Alain; Bosio, Maurizio; Caprio, Massimiliano; Poulet-Young, Véronique; Chabrolle, Jean-Pierre; Niaudet, Patrick; De Gennes, Christiane; Lecornec, Marie-Hélène; Poisson, Elodie; Fusco, Anna Maria; Loli, Paola; Lombès, Marc; Zennaro, Maria-Christina

    2003-06-01

    We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease. PMID:12788847

  6. Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism.

    PubMed

    Sartorato, Paola; Lapeyraque, Anne-Laure; Armanini, Decio; Kuhnle, Ursula; Khaldi, Yasmina; Salomon, Rémi; Abadie, Véronique; Di Battista, Eliana; Naselli, Arturo; Racine, Alain; Bosio, Maurizio; Caprio, Massimiliano; Poulet-Young, Véronique; Chabrolle, Jean-Pierre; Niaudet, Patrick; De Gennes, Christiane; Lecornec, Marie-Hélène; Poisson, Elodie; Fusco, Anna Maria; Loli, Paola; Lombès, Marc; Zennaro, Maria-Christina

    2003-06-01

    We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease.

  7. The amphibians Xenopus laevis and Silurana tropicalis possess a family of activating KIR-related Immunoglobulin-like receptors

    PubMed Central

    Guselnikov, Sergey V; Reshetnikova, Evdokiya S; Najakshin, Alexander M; Mechetina, Ludmila V; Robert, Jacques; Taranin, Alexander V

    2009-01-01

    In this study, we searched the amphibian species Xenopus laevis and Silurana (Xenopus) tropicalis for the presence of genes homologous to mammalian KIRs and avian CHIRs (KRIR family). By experimental and computational procedures, we identified four related ILR (Ig-like receptors) genes in S. tropicalis and three in X. laevis. ILRs encode type I transmembrane receptors with 3–4 Ig-like extracellular domains. All predicted ILR proteins appear to be activating receptors. ILRs have a broad expression pattern, the gene transcripts were found in both lymphoid and non-lymphoid tissues. Phylogenetic analysis shows that the amphibian KRIR family receptors evolved independently from their mammalian and avian counterparts. The only conserved structural element of tetrapod KRIRs is the NxxR motif-containing transmembrane domain that facilitates association with FcR subunit. Our findings suggest that if KRIRs of various vertebrates have any common function at all, such a function is activating rather than inhibitory. PMID:19896971

  8. Plant nuclear hormone receptors: a role for small molecules in protein-protein interactions.

    PubMed

    Lumba, Shelley; Cutler, Sean; McCourt, Peter

    2010-01-01

    Plant hormones are a group of chemically diverse small molecules that direct processes ranging from growth and development to biotic and abiotic stress responses. Surprisingly, genome analyses suggest that classic animal nuclear hormone receptor homologs do not exist in plants. It now appears that plants have co-opted several protein families to perceive hormones within the nucleus. In one solution to the problem, the hormones auxin and jasmonate (JA) act as “molecular glue” that promotes protein-protein interactions between receptor F-boxes and downstream corepressor targets. In another solution, gibberellins (GAs) bind and elicit a conformational change in a novel soluble receptor family related to hormone-sensitive lipases. Abscisic acid (ABA), like GA, also acts through an allosteric mechanism involving a START-domain protein. The molecular identification of plant nuclear hormone receptors will allow comparisons with animal nuclear receptors and testing of fundamental questions about hormone function in plant development and evolution.

  9. Receptor Activity-modifying Protein-directed G Protein Signaling Specificity for the Calcitonin Gene-related Peptide Family of Receptors*

    PubMed Central

    Weston, Cathryn; Winfield, Ian; Harris, Matthew; Hodgson, Rose; Shah, Archna; Dowell, Simon J.; Mobarec, Juan Carlos; Woodlock, David A.; Reynolds, Christopher A.; Poyner, David R.; Watkins, Harriet A.; Ladds, Graham

    2016-01-01

    The calcitonin gene-related peptide (CGRP) family of G protein-coupled receptors (GPCRs) is formed through the association of the calcitonin receptor-like receptor (CLR) and one of three receptor activity-modifying proteins (RAMPs). Binding of one of the three peptide ligands, CGRP, adrenomedullin (AM), and intermedin/adrenomedullin 2 (AM2), is well known to result in a Gαs-mediated increase in cAMP. Here we used modified yeast strains that couple receptor activation to cell growth, via chimeric yeast/Gα subunits, and HEK-293 cells to characterize the effect of different RAMP and ligand combinations on this pathway. We not only demonstrate functional couplings to both Gαs and Gαq but also identify a Gαi component to CLR signaling in both yeast and HEK-293 cells, which is absent in HEK-293S cells. We show that the CGRP family of receptors displays both ligand- and RAMP-dependent signaling bias among the Gαs, Gαi, and Gαq/11 pathways. The results are discussed in the context of RAMP interactions probed through molecular modeling and molecular dynamics simulations of the RAMP-GPCR-G protein complexes. This study further highlights the importance of RAMPs to CLR pharmacology and to bias in general, as well as identifying the importance of choosing an appropriate model system for the study of GPCR pharmacology. PMID:27566546

  10. Genome Sequence of vB_AbaS_TRS1, a Viable Prophage Isolated from Acinetobacter baumannii Strain A118

    PubMed Central

    Turner, Dann; Wand, Matthew E.; Sutton, J. Mark; Centron, Daniela; Kropinski, Andrew M.

    2016-01-01

    A novel temperate phage, vB_AbaS_TRS1, was isolated from cultures of Acinetobacter baumannii strain A118 that had been exposed to mitomycin C. Phage TRS1 belongs to the Siphoviridae family of bacteriophages and encapsulates a 40,749-bp genome encoding 70 coding sequences and a single tRNA. PMID:27738026

  11. Formative Evaluation of an ABA Outreach Training Program for Parents of Children with Autism in Remote Areas

    ERIC Educational Resources Information Center

    Heitzman-Powell, Linda S.; Buzhardt, Jay; Rusinko, Lisa C.; Miller, Todd M.

    2014-01-01

    Families in rural or remote areas have limited access to evidence-based intervention for their children with autism. Using web-based training and telemedicine technology, the current study investigated the feasibility of training seven parents to implement Applied Behavior Analysis (ABA) strategies with their children with autism. In this…

  12. Mechanisms of signal transduction by ethylene: overlapping and non-overlapping signalling roles in a receptor family

    PubMed Central

    Shakeel, Samina N.; Wang, Xiaomin; Binder, Brad M.; Schaller, G. Eric

    2013-01-01

    The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional regulation within the nucleus. Here, we present our current understanding of ethylene signal transduction, focusing on recent developments that support a model with overlapping and non-overlapping roles for members of the ethylene receptor family. We consider the evidence supporting this model for sub-functionalization within the receptor family, and then discuss mechanisms by which such a sub-functionalization may occur. To this end, we consider the importance of receptor interactions in modulating their signal output and how such interactions vary in the receptor family. In addition, we consider evidence indicating that ethylene signal output by the receptors involves both phosphorylation-dependent and phosphorylation-independent mechanisms. We conclude with a current model for signalling by the ethylene receptors placed within the overall context of ethylene signal transduction. PMID:23543258

  13. The Nod-Like Receptor (NLR) Family: A Tale of Similarities and Differences

    PubMed Central

    Proell, Martina; Riedl, Stefan J.; Fritz, Jörg H.; Rojas, Ana M.; Schwarzenbacher, Robert

    2008-01-01

    Innate immunity represents an important system with a variety of vital processes at the core of many diseases. In recent years, the central role of the Nod-like receptor (NLR) protein family became increasingly appreciated in innate immune responses. NLRs are classified as part of the signal transduction ATPases with numerous domains (STAND) clade within the AAA+ ATPase family. They typically feature an N-terminal effector domain, a central nucleotide-binding domain (NACHT) and a C-terminal ligand-binding region that is composed of several leucine-rich repeats (LRRs). NLRs are believed to initiate or regulate host defense pathways through formation of signaling platforms that subsequently trigger the activation of inflammatory caspases and NF-kB. Despite their fundamental role in orchestrating key pathways in innate immunity, their mode of action in molecular terms remains largely unknown. Here we present the first comprehensive sequence and structure modeling analysis of NLR proteins, revealing that NLRs posses a domain architecture similar to the apoptotic initiator protein Apaf-1. Apaf-1 performs its cellular function by the formation of a heptameric platform, dubbed apoptosome, ultimately triggering the controlled demise of the affected cell. The mechanism of apoptosome formation by Apaf-1 potentially offers insight into the activation mechanisms of NLR proteins. Multiple sequence alignment analysis and homology modeling revealed Apaf-1-like structural features in most members of the NLR family, suggesting a similar biochemical behaviour in catalytic activity and oligomerization. Evolutionary tree comparisons substantiate the conservation of characteristic functional regions within the NLR family and are in good agreement with domain distributions found in distinct NLRs. Importantly, the analysis of LRR domains reveals surprisingly low conservation levels among putative ligand-binding motifs. The same is true for the effector domains exhibiting distinct

  14. The plant-specific SR45 protein negatively regulates glucose and ABA signaling during early seedling development in Arabidopsis.

    PubMed

    Carvalho, Raquel Fonseca; Carvalho, Sofia Domingues; Duque, Paula

    2010-10-01

    The plant-specific SR45 belongs to the highly conserved family of serine/arginine-rich (SR) proteins, which play key roles in precursor-mRNA splicing and other aspects of RNA metabolism. An Arabidopsis (Arabidopsis thaliana) loss-of-function mutant, sr45-1, displays pleiotropic phenotypes, such as defects in flower and leaf morphology, root growth, and flowering time. Here, we show that the sr45-1 mutation confers hypersensitivity to glucose (Glc) during early seedling growth in Arabidopsis. Unlike wild-type plants, the sr45-1 mutant displays impaired cotyledon greening and expansion as well as reduced hypocotyl elongation of dark-grown seedlings when grown in the presence of low (3%) Glc concentrations. In addition, SR45 is involved in the control of Glc-responsive gene expression, as the mutant displays enhanced repression of photosynthetic and nitrogen metabolism genes and overinduction of starch and anthocyanin biosynthesis genes. Like many other sugar response mutants, sr45-1 also shows hypersensitivity to abscisic acid (ABA) but appears to be unaffected in ethylene signaling. Importantly, the sr45-1 mutant shows enhanced ability to accumulate ABA in response to Glc, and the ABA biosynthesis inhibitor fluridone partially rescues the sugar-mediated growth arrest. Moreover, three ABA biosynthesis genes and two key ABA signaling genes, ABI3 and ABI5, are markedly overinduced by Glc in sr45-1. These results provide evidence that the SR45 protein defines a novel player in plant sugar response that negatively regulates Glc signaling during early seedling development by down-regulating both Glc-specific ABA accumulation and ABA biosynthesis and signaling gene expression. PMID:20699397

  15. Characterization of Triticum aestivum Abscisic Acid Receptors and a Possible Role for These in Mediating Fusairum Head Blight Susceptibility in Wheat

    PubMed Central

    Gordon, Cameron S.; Rajagopalan, Nandhakishore; Risseeuw, Eddy P.; Surpin, Marci; Ball, Fraser J.; Barber, Carla J.; Buhrow, Leann M.; Clark, Shawn M.; Page, Jonathan E.; Todd, Chris D.; Abrams, Suzanne R.; Loewen, Michele C.

    2016-01-01

    Abscisic acid (ABA) is a well-characterized plant hormone, known to mediate developmental aspects as well as both abiotic and biotic stress responses. Notably, the exogenous application of ABA has recently been shown to increase susceptibility to the fungal pathogen Fusarium graminearum, the causative agent of Fusarium head blight (FHB) in wheat and other cereals. However roles and mechanisms associated with ABA’s modulation of pathogen responses remain enigmatic. Here the identification of putative ABA receptors from available genomic databases for Triticum aestivum (bread wheat) and Brachypodium distachyon (a model cereal) are reported. A number of these were cloned for recombinant expression and their functionality as ABA receptors confirmed by in vitro assays against protein phosphatases Type 2Cs. Ligand selectivity profiling of one of the wheat receptors (Ta_PYL2DS_FL) highlighted unique activities compared to Arabidopsis AtPYL5. Mutagenic analysis showed Ta_PYL2DS_FL amino acid D180 as being a critical contributor to this selectivity. Subsequently, a virus induced gene silencing (VIGS) approach was used to knockdown wheat Ta_PYL4AS_A (and similar) in planta, yielding plants with increased early stage resistance to FHB progression and decreased mycotoxin accumulation. Together these results confirm the existence of a family of ABA receptors in wheat and Brachypodium and present insight into factors modulating receptor function at the molecular level. That knockdown of Ta_PYL4AS_A (and similar) leads to early stage FHB resistance highlights novel targets for investigation in the future development of disease resistant crops. PMID:27755583

  16. Protein interactions with HER-family receptors can have different characteristics depending on the hosting cell line.

    PubMed

    Barta, Pavel; Malmberg, Jennie; Melicharova, Ludmila; Strandgård, John; Orlova, Anna; Tolmachev, Vladimir; Laznicek, Milan; Andersson, Karl

    2012-05-01

    Cell lines are common model systems in the development of therapeutic proteins and in the research on cellular functions and dysfunctions. In this field, the protein interaction assay is a frequently used tool for assessing the adequacy of a protein for diagnostic and therapeutic purposes. In this study, we investigated the extent to which the interaction characteristics depend on the choice of cell line for HER-family receptors. The interaction characteristics of two therapeutic antibodies (trastuzumab and cetuximab) and one Affibody molecule (ZHER2:342), interacting with the intended receptor were characterized with high precision using an automated real-time interaction method, in different cell lines (HaCaT, A431, HEP-G2, SKOV3, PC3, DU-145). Clear differences in binding affinity and kinetics, up to one order of magnitude, were found for the interaction of the same protein binding to the same receptor on different cells for all three proteins. For HER-family receptors, it is therefore important to refer to the measured affinity for a protein-receptor interaction together with the hosting cell line. The ability to accurately measure affinity and kinetics of a protein-receptor interaction on cell lines of different origins may increase the understanding of underlying receptor biology, and impact the selection of candidates in the development of therapeutic or diagnostic agents. PMID:22200885

  17. Minireview: Nuclear Receptor Coregulators of the p160 Family: Insights into Inflammation and Metabolism

    PubMed Central

    Rollins, David A.; Coppo, Maddalena

    2015-01-01

    Nuclear receptor coactivators (NCOAs) are multifunctional transcriptional coregulators for a growing number of signal-activated transcription factors. The members of the p160 family (NCOA1/2/3) are increasingly recognized as essential and nonredundant players in a number of physiological processes. In particular, accumulating evidence points to the pivotal roles that these coregulators play in inflammatory and metabolic pathways, both under homeostasis and in disease. Given that chronic inflammation of metabolic tissues (“metainflammation”) is a driving force for the widespread epidemic of obesity, insulin resistance, cardiovascular disease, and associated comorbidities, deciphering the role of NCOAs in “normal” vs “pathological” inflammation and in metabolic processes is indeed a subject of extreme biomedical importance. Here, we review the evolving and, at times, contradictory, literature on the pleiotropic functions of NCOA1/2/3 in inflammation and metabolism as related to nuclear receptor actions and beyond. We then briefly discuss the potential utility of NCOAs as predictive markers for disease and/or possible therapeutic targets once a better understanding of their molecular and physiological actions is achieved. PMID:25647480

  18. Regulation of the neuronal nicotinic acetylcholine receptor by SRC family tyrosine kinases.

    PubMed

    Wang, Kan; Hackett, John T; Cox, Michael E; Van Hoek, Monique; Lindstrom, Jon M; Parsons, Sarah J

    2004-03-01

    Src family kinases (SFKs) are abundant in chromaffin cells that reside in the adrenal medulla and respond to cholinergic stimulation by secreting catecholamines. Our previous work indicated that SFKs regulate acetylcholine- or nicotine-induced secretion, but the site of modulatory action was unclear. Using whole cell recordings, we found that inhibition of SFK tyrosine kinase activity by PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine) treatment or expression of a kinase-defective c-Src reduced the peak amplitude of nicotine-induced currents in chromaffin cells or in human embryonic kidney cells ectopically expressing functional neuronal alpha3beta4alpha5 acetylcholine receptors (AChRs). Conversely, the phosphotyrosine phosphatase inhibitor, sodium vanadate, or expression of mutationally activated c-Src resulted in enhanced current amplitudes. These results suggest that SFKs and putative phosphotyrosine phosphatases regulate the activity of AChRs by opposing actions. This proposed model was supported further by the findings that SFKs physically associate with the receptor and that the AChR is tyrosine-phosphorylated.

  19. The AP-1 family member FOS blocks transcriptional activity of the nuclear receptor steroidogenic factor 1

    PubMed Central

    Sirianni, Rosa; Nogueira, Edson; Bassett, Mary H.; Carr, Bruce R.; Suzuki, Takashi; Pezzi, Vincenzo; Andò, Sebastiano; Rainey, William E.

    2010-01-01

    Steroid production in the adrenal zona glomerulosa is under the control of angiotensin II (Ang II), which, upon binding to its receptor, activates protein kinase C (PKC) within these cells. PKC is a potent inhibitor of the steroidogenic enzyme CYP17. We have demonstrated that, in the ovary, PKC activates expression of FOS, a member of the AP-1 family, and increased expression of this gene is linked to CYP17 downregulation. However, the pathway and the molecular mechanism responsible for the inhibitory effect of PKC on CYP17 expression are not defined. Herein, we demonstrated that Ang II inhibited CYP17 through PKC and ERK1/2-activated FOS and that blocking FOS expression decreased PKC-mediated inhibition. Although CYP17 transcription was activated by the nuclear receptor SF-1, expression of FOS resulted in a decrease in SF-1-mediated gene transcription. FOS physically interacted with the hinge region of SF-1 and modulated its transactivity, thus preventing binding of cofactors such as SRC1 and CBP, which were necessary to fully activate CYP17 transcription. Collectively, these results indicate a new regulatory mechanism for SF-1 transcriptional activity that might influence adrenal zone-specific expression of CYP17, a mechanism that can potentially be applied to other steroidogenic tissues. PMID:20980388

  20. Role of nutrient-sensing taste 1 receptor (T1R) family members in gastrointestinal chemosensing.

    PubMed

    Shirazi-Beechey, Soraya P; Daly, Kristian; Al-Rammahi, Miran; Moran, Andrew W; Bravo, David

    2014-06-01

    Luminal nutrient sensing by G-protein-coupled receptors (GPCR) expressed on the apical domain of enteroendocrine cells activates intracellular pathways leading to secretion of gut hormones that control vital physiological processes such as digestion, absorption, food intake and glucose homeostasis. The taste 1 receptor (T1R) family of GPCR consists of three members: T1R1; T1R2; T1R3. Expression of T1R1, T1R2 and T1R3 at mRNA and protein levels has been demonstrated in the intestinal tissue of various species. It has been shown that T1R2-T1R3, in association with G-protein gustducin, is expressed in intestinal K and L endocrine cells, where it acts as the intestinal glucose (sweet) sensor. A number of studies have demonstrated that activation of T1R2-T1R3 by natural sugars and artificial sweeteners leads to secretion of glucagon-like peptides 1&2 (GLP-1 and GLP-2) and glucose dependent insulinotropic peptide (GIP). GLP-1 and GIP enhance insulin secretion; GLP-2 increases intestinal growth and glucose absorption. T1R1-T1R3 combination co-expressed on the apical domain of cholecystokinin (CCK) expressing cells is a luminal sensor for a number of L-amino acids; with amino acid-activation of the receptor eliciting CCK secretion. This article focuses on the role of the gut-expressed T1R1, T1R2 and T1R3 in intestinal sweet and L-amino acid sensing. The impact of exploiting T1R2-T1R3 as a nutritional target for enhancing intestinal glucose absorption and gut structural maturity in young animals is also highlighted.

  1. Stabilin-1 and -2 constitute a novel family of fasciclin-like hyaluronan receptor homologues.

    PubMed Central

    Politz, Oliver; Gratchev, Alexei; McCourt, Peter A G; Schledzewski, Kai; Guillot, Pierre; Johansson, Sophie; Svineng, Gunbjorg; Franke, Peter; Kannicht, Christoph; Kzhyshkowska, Julia; Longati, Paola; Velten, Florian W; Johansson, Staffan; Goerdt, Sergij

    2002-01-01

    MS-1, a high-molecular-mass protein expressed by non-continuous and angiogenic endothelial cells and by alternatively activated macrophages (Mphi2), and the hepatic sinusoidal endothelial hyaluronan clearance receptor are similar with respect to tissue distribution and biochemical characteristics. In the present study we purified these proteins by immuno- and hyaluronan-affinity chromatography respectively, sequenced tryptic peptides and generated full-length cDNA sequences in both mouse and human. The novel genes, i.e. stabilin-1 and stabilin-2, code for homologous transmembrane proteins featuring seven fasciclin-like adhesion domains, 18-20 epidermal-growth-factor domains, one X-link domain and three to six B-(X(7))-B hyaluronan-binding motifs. Northern-blotting experiments revealed the presence of both stabilins in organs with predominant endothelial sinuses such as liver, spleen and lymph node: stabilin-1 mRNA was also detected in organs with predominant Mphi2 cells, such as placenta, and in interleukin-4/glucocorticoid-stimulated Mphi2 cells in vitro. A polyclonal antibody made against human recombinant stabilin-1 confirmed the expression of stabilin-1 protein in splenic sinus endothelial cells in vivo and in Mphi2 in vitro. On the basis of high similarity at the protein level and the unique domain composition, which differs from that of all other known fasciclin-like proteins and hyaluronan receptors, stabilin-1 and stabilin-2 define a novel family of fasciclin-like hyaluronan receptor homologues that might play a role in cell-cell and cell-matrix interactions in vascular function and inflammatory processes. PMID:11829752

  2. The p160/Steroid Receptor Coactivator Family: Potent Arbiters of Uterine Physiology and Dysfunction1

    PubMed Central

    Szwarc, Maria M.; Kommagani, Ramakrishna; Lessey, Bruce A.; Lydon, John P.

    2014-01-01

    ABSTRACT The p160/steroid receptor coactivator (SRC) family comprises three pleiotropic coregulators (SRC-1, SRC-2, and SRC-3; otherwise known as NCOA1, NCOA2, and NCOA3, respectively), which modulate a wide spectrum of physiological responses and clinicopathologies. Such pleiotropy is achieved through their inherent structural complexity, which allows this coregulator class to control both nuclear receptor and non-nuclear receptor signaling. As observed in other physiologic systems, members of the SRC family have recently been shown to play pivotal roles in uterine biology and pathobiology. In the murine uterus, SRC-1 is required to launch a full steroid hormone response, without which endometrial decidualization is markedly attenuated. From “dovetailing” clinical and mouse studies, an isoform of SRC-1 was recently identified which promotes endometriosis by reprogramming endometrial cells to evade apoptosis and to colonize as endometriotic lesions within the peritoneal cavity. The endometrium fails to decidualize without SRC-2, which accounts for the infertility phenotype exhibited by mice devoid of this coregulator. In related studies on human endometrial stromal cells, SRC-2 was shown to act as a molecular “pacemaker” of the glycolytic flux. This finding is significant because acceleration of the glycolytic flux provides the necessary bioenergy and biomolecules for endometrial stromal cells to switch from quiescence to a proliferative phenotype, a critical underpinning in the decidual progression program. Although studies on uterine SRC-3 function are in their early stages, clinical studies provide tantalizing support for the proposal that SRC-3 is causally linked to endometrial hyperplasia as well as with endometrial pathologies in patients diagnosed with polycystic ovary syndrome. This proposal is now driving the development and application of innovative technologies, particularly in the mouse, to further understand the functional role of this elusive

  3. The nicotinic acetylcholine receptor gene family of the malaria mosquito, Anopheles gambiae.

    PubMed

    Jones, Andrew K; Grauso, Marta; Sattelle, David B

    2005-02-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission in the insect nervous system and are targets of widely selling insecticides. We have identified the nAChR gene family from the genome of the malaria mosquito vector, Anopheles gambiae, to be the second complete insect nAChR gene family described following that of Drosophila melanogaster. Like Drosophila, Anopheles possesses 10 nAChR subunits with orthologous relationships evident between the two insects. Interestingly, the Anopheles orthologues of Dbeta2 and Dbeta3 possess the vicinal cysteines that define alpha subunits. As with Dalpha4 and Dalpha6, the Anopheles orthologues are alternatively spliced at equivalent exons. Reverse transcription-polymerase chain reaction analysis shows that RNA A-to-I editing sites conserved between Dalpha6 of Drosophila and alpha7-2 of the tobacco budworm, Heliothis virescens, are not shared with the equivalent nAChR subunit of Anopheles. Indeed, RNA-editing sites identified in functionally significant regions of Dbeta1, Dalpha5, and Dalpha6 are not conserved in the mosquito orthologues, indicating considerable divergence of RNA molecules targeted for editing within the insect order Diptera. These findings shed further light on the diversity of nAChR subunits and may present a useful basis for the development of improved malaria control agents by enhancing our understanding of a validated mosquito insecticide target.

  4. The human thyrotropin receptor: a heptahelical receptor capable of stimulating members of all four G protein families.

    PubMed Central

    Laugwitz, K L; Allgeier, A; Offermanns, S; Spicher, K; Van Sande, J; Dumont, J E; Schultz, G

    1996-01-01

    Thyrotropin is the primary hormone that, via one heptahelical receptor, regulates thyroid cell functions such as secretion, specific gene expression, and growth. In human thyroid, thyrotropin receptor activation leads to stimulation of the adenylyl cyclase and phospholipase C cascades. However, the G proteins involved in thyrotropin receptor action have been only partially defined. In membranes of human thyroid gland, we immunologically identified alpha subunits of the G proteins Gs short, Gs long, Gi1, Gi2, Gi3, G(o) (Go2 and another form of Go, presumably Go1), Gq, G11, G12, and G13. Activation of the thyrotropin (TSH) receptor by bovine TSH led to increased incorporation of the photoreactive GTP analogue [alpha-32P]GTP azidoanilide into immunoprecipitated alpha subunits of all G proteins detected in thyroid membranes. This effect was receptor-dependent and not due to direct G protein stimulation because it was mimicked by TSH receptor-stimulating antibodies of patients suffering from Grave disease and was abolished by a receptor-blocking antiserum from a patient with autoimmune hypothyroidism. The TSH-induced activation of individual G proteins occurred with EC50 values of 5-50 milliunits/ml, indicating that the activated TSH receptor coupled with similar potency to different G proteins. When human thyroid slices were pretreated with pertussis toxin, the TSH receptor-mediated accumulation of cAMP increased by approximately 35% with TSH at 1 milliunits/ml, indicating that the TSH receptor coupled to Gs and G(i). Taken together, these findings show that, at least in human thyroid membranes, in which the protein is expressed at its physiological levels, the TSH receptor resembles a naturally occurring example of a general G protein-activating receptor. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8552586

  5. ABA says NO to UV-B: a universal response?

    PubMed

    Tossi, Vanesa; Cassia, Raul; Bruzzone, Santina; Zocchi, Elena; Lamattina, Lorenzo

    2012-09-01

    Abscisic acid (ABA) signaling pathways have been widely characterized in plants, whereas the function of ABA in animals is less well understood. However, recent advances show ABA production by a wide range of lower animals and higher mammals. This enables a new evaluation of ABA signaling pathways in different organisms in response to common environmental stress, such as ultraviolet (UV)-B. In this opinion article, we propose that the induction of common signaling components, such as ABA, nitric oxide (NO) and Ca(2+), in plant and animal cells in response to high doses of UV-B, suggests that the evolution of a general mechanism activated by UV-B is conserved in divergent multicellular organisms challenged by a changing common environment.

  6. Functional Expression of Two Neuronal Nicotinic Acetylcholine Receptors from cDNA Clones Identifies a Gene Family

    NASA Astrophysics Data System (ADS)

    Boulter, Jim; Connolly, John; Deneris, Evan; Goldman, Dan; Heinemann, Steven; Patrick, Jim

    1987-11-01

    A family of genes coding for proteins homologous to the α subunit of the muscle nicotinic acetylcholine receptor has been identified in the rat genome. These genes are transcribed in the central and peripheral nervous systems in areas known to contain functional nicotinic receptors. In this paper, we demonstrate that three of these genes, which we call alpha3, alpha4, and beta2, encode proteins that form functional nicotinic acetylcholine receptors when expressed in Xenopus oocytes. Oocytes expressing either alpha3 or alpha4 protein in combination with the beta2 protein produced a strong response to acetylcholine. Oocytes expressing only the alpha4 protein gave a weak response to acetylcholine. These receptors are activated by acetylcholine and nicotine and are blocked by Bungarus toxin 3.1. They are not blocked by α -bungarotoxin, which blocks the muscle nicotinic acetylcholine receptor. Thus, the receptors formed by the alpha3, alpha4, and beta2 subunits are pharmacologically similar to the ganglionic-type neuronal nicotinic acetylcholine receptor. These results indicate that the alpha3, alpha4, and beta2 genes encode functional nicotinic acetylcholine receptor subunits that are expressed in the brain and peripheral nervous system.

  7. A hub for ABA signaling to the nucleus: significance of a cytosolic and nuclear dual-localized PPR protein SOAR1 acting downstream of Mg-chelatase H subunit.

    PubMed

    Jiang, Shang-Chuan; Mei, Chao; Wang, Xiao-Fang; Zhang, Da-Peng

    2014-01-01

    SOAR1 is a cytosol-nucleus dual-localized pentatricopeptide repeat (PPR) protein, which we indentified recently as a crucial regulator in the CHLH/ABAR (Mg-chelatase H subunit /putative ABA receptor)-mediated signaling pathway, acting downstream of CHLH/ABAR and upstream of a nuclear ABA-responsive bZIP transcription factor ABI5. Downregulation and upregulation of SOAR1 expression alter dramatically both ABA sensitivity and expression of a subset of key, nuclear ABA-responsive genes, suggesting that SOAR1 is a hub for ABA signaling to the nucleus, and CHLH/ABAR mediates a central signaling pathway to regulate downstream gene expression through SOAR1.

  8. Expression of bitter taste receptors of the T2R family in the gastrointestinal tract and enteroendocrine STC-1 cells

    PubMed Central

    Wu, S. Vincent; Rozengurt, Nora; Yang, Moon; Young, Steven H.; Sinnett-Smith, James; Rozengurt, Enrique

    2002-01-01

    Although a role for the gastric and intestinal mucosa in molecular sensing has been known for decades, the initial molecular recognition events that sense the chemical composition of the luminal contents has remained elusive. Here we identified putative taste receptor gene transcripts in the gastrointestinal tract. Our results, using reverse transcriptase–PCR, demonstrate the presence of transcripts corresponding to multiple members of the T2R family of bitter taste receptors in the antral and fundic gastric mucosa as well as in the lining of the duodenum. In addition, cDNA clones of T2R receptors were detected in a rat gastric endocrine cell cDNA library, suggesting that these receptors are expressed, at least partly, in enteroendocrine cells. Accordingly, expression of multiple T2R receptors also was found in STC-1 cells, an enteroendocrine cell line. The expression of α subunits of G proteins implicated in intracellular taste signal transduction, namely Gαgust, and Gαt-2, also was demonstrated in the gastrointestinal mucosa as well as in STC-1 cells, as revealed by reverse transcriptase–PCR and DNA sequencing, immunohistochemistry, and Western blotting. Furthermore, addition of compounds widely used in bitter taste signaling (e.g., denatonium, phenylthiocarbamide, 6-n-propil-2-thiouracil, and cycloheximide) to STC-1 cells promoted a rapid increase in intracellular Ca2+ concentration. These results demonstrate the expression of bitter taste receptors of the T2R family in the mouse and rat gastrointestinal tract. PMID:11854532

  9. Application of comparative genomics in the identification and analysis of novel families of membrane-associated receptors in bacteria

    PubMed Central

    Anantharaman, Vivek; Aravind, L

    2003-01-01

    Background A great diversity of multi-pass membrane receptors, typically with 7 transmembrane (TM) helices, is observed in the eukaryote crown group. So far, they are relatively rare in the prokaryotes, and are restricted to the well-characterized sensory rhodopsins of various phototropic prokaryotes. Results Utilizing the currently available wealth of prokaryotic genomic sequences, we set up a computational screen to identify putative 7 (TM) and other multi-pass membrane receptors in prokaryotes. As a result of this procedure we were able to recover two widespread families of 7 TM receptors in bacteria that are distantly related to the eukaryotic 7 TM receptors and prokaryotic rhodopsins. Using sequence profile analysis, we were able to establish that the first members of these receptor families contain one of two distinct N-terminal extracellular globular domains, which are predicted to bind ligands such as carbohydrates. In their intracellular portions they contain fusions to a variety of signaling domains, which suggest that they are likely to transduce signals via cyclic AMP, cyclic diguanylate, histidine phosphorylation, dephosphorylation, and through direct interactions with DNA. The second family of bacterial 7 TM receptors possesses an α-helical extracellular domain, and is predicted to transduce a signal via an intracellular HD hydrolase domain. Based on comparative analysis of gene neighborhoods, this receptor is predicted to function as a regulator of the diacylglycerol-kinase-dependent glycerolipid pathway. Additionally, our procedure also recovered other types of putative prokaryotic multi-pass membrane associated receptor domains. Of these, we characterized two widespread, evolutionarily mobile multi-TM domains that are fused to a variety of C-terminal intracellular signaling domains. One of these typified by the Gram-positive LytS protein is predicted to be a potential sensor of murein derivatives, whereas the other one typified by the Escherichia

  10. PYR/PYL/RCAR Abscisic Acid Receptors Regulate K+ and Cl− Channels through Reactive Oxygen Species-Mediated Activation of Ca2+ Channels at the Plasma Membrane of Intact Arabidopsis Guard Cells1[W][OPEN

    PubMed Central

    Wang, Yizhou; Chen, Zhong-Hua; Zhang, Ben; Hills, Adrian; Blatt, Michael R.

    2013-01-01

    The discovery of the START family of abscisic acid (ABA) receptors places these proteins at the front of a protein kinase/phosphatase signal cascade that promotes stomatal closure. The connection of these receptors to Ca2+ signals evoked by ABA has proven more difficult to resolve, although it has been implicated by studies of the pyrbactin-insensitive pyr1/pyl1/pyl2/pyl4 quadruple mutant. One difficulty is that flux through plasma membrane Ca2+ channels and Ca2+ release from endomembrane stores coordinately elevate cytosolic free Ca2+ concentration ([Ca2+]i) in guard cells, and both processes are facilitated by ABA. Here, we describe a method for recording Ca2+ channels at the plasma membrane of intact guard cells of Arabidopsis (Arabidopsis thaliana). We have used this method to resolve the loss of ABA-evoked Ca2+ channel activity at the plasma membrane in the pyr1/pyl1/pyl2/pyl4 mutant and show the consequent suppression of [Ca2+]i increases in vivo. The basal activity of Ca2+ channels was not affected in the mutant; raising the concentration of Ca2+ outside was sufficient to promote Ca2+ entry, to inactivate current carried by inward-rectifying K+ channels and to activate current carried by the anion channels, both of which are sensitive to [Ca2+]i elevations. However, the ABA-dependent increase in reactive oxygen species (ROS) was impaired. Adding the ROS hydrogen peroxide was sufficient to activate the Ca2+ channels and trigger stomatal closure in the mutant. These results offer direct evidence of PYR/PYL/RCAR receptor coupling to the activation by ABA of plasma membrane Ca2+ channels through ROS, thus affecting [Ca2+]i and its regulation of stomatal closure. PMID:23899646

  11. The emergence of the vasopressin and oxytocin hormone receptor gene family lineage: Clues from the characterization of vasotocin receptors in the sea lamprey (Petromyzon marinus).

    PubMed

    Mayasich, Sally A; Clarke, Benjamin L

    2016-01-15

    The sea lamprey (Petromyzon marinus) is a jawless vertebrate at an evolutionary nexus between invertebrates and jawed vertebrates. Lampreys are known to possess the arginine vasotocin (AVT) hormone utilized by all non-mammalian vertebrates. We postulated that the lamprey would possess AVT receptor orthologs of predecessors to the arginine vasopressin (AVP)/oxytocin (OXT) family of G protein-coupled receptors found in mammals, providing insights into the origins of the mammalian V1A, V1B, V2 and OXT receptors. Among the earliest animals to diverge from the vertebrate lineage in which these receptors are characterized is the jawed, cartilaginous elephant shark, which has genes orthologous to all four mammalian receptor types. Therefore, our work was aimed at helping resolve the critical gap concerning the outcomes of hypothesized large-scale (whole-genome) duplication events. We sequenced one partial and four full-length putative lamprey AVT receptor genes and determined their mRNA expression patterns in 15 distinct tissues. Phylogenetically, three of the full-coding genes possess structural characteristics of the V1 clade containing the V1A, V1B and OXT receptors. Another full-length coding gene and the partial sequence are part of the V2 clade and appear to be most closely related to the newly established V2B and V2C receptor subtypes. Our synteny analysis also utilizing the Japanese lamprey (Lethenteron japonicum) genome supports the recent proposal that jawless and jawed vertebrates shared one-round (1R) of WGD as the most likely scenario.

  12. Genome-Wide Analysis of the bZIP Gene Family Identifies Two ABI5-Like bZIP Transcription Factors, BrABI5a and BrABI5b, as Positive Modulators of ABA Signalling in Chinese Cabbage.

    PubMed

    Bai, Yili; Zhu, Wenbo; Hu, Xiaochen; Sun, Congcong; Li, Yanlin; Wang, Dandan; Wang, Qinhu; Pei, Guoliang; Zhang, Yanfeng; Guo, Aiguang; Zhao, Huixian; Lu, Haibin; Mu, Xiaoqian; Hu, Jingjiang; Zhou, Xiaona; Xie, Chang Gen

    2016-01-01

    bZIP (basic leucine zipper) transcription factors coordinate plant growth and development and control responses to environmental stimuli. The genome of Chinese cabbage (Brassica rapa) encodes 136 putative bZIP transcription factors. The bZIP transcription factors in Brassica rapa (BrbZIP) are classified into 10 subfamilies. Phylogenetic relationship analysis reveals that subfamily A consists of 23 BrbZIPs. Two BrbZIPs within subfamily A, Bra005287 and Bra017251, display high similarity to ABI5 (ABA Insensitive 5). Expression of subfamily A BrbZIPs, like BrABI5a (Bra005287/BrbZIP14) and BrABI5b (Bra017251/BrbZIP13), are significantly induced by the plant hormone ABA. Subcellular localization assay reveal that both BrABI5a and BrABI5b have a nuclear localization. BrABI5a and BrABI5b could directly stimulate ABA Responsive Element-driven HIS (a HIS3 reporter gene, which confers His prototrophy) or LUC (LUCIFERASE) expression in yeast and Arabidopsis protoplast. Deletion of the bZIP motif abolished BrABI5a and BrABI5b transcriptional activity. The ABA insensitive phenotype of Arabidopsis abi5-1 is completely suppressed in transgenic lines expressing BrABI5a or BrABI5b. Overall, these results suggest that ABI5 orthologs, BrABI5a and BrABI5b, have key roles in ABA signalling in Chinese cabbage.

  13. Genome-Wide Analysis of the bZIP Gene Family Identifies Two ABI5-Like bZIP Transcription Factors, BrABI5a and BrABI5b, as Positive Modulators of ABA Signalling in Chinese Cabbage

    PubMed Central

    Hu, Xiaochen; Sun, Congcong; Li, Yanlin; Wang, Dandan; Wang, Qinhu; Pei, Guoliang; Zhang, Yanfeng; Guo, Aiguang; Zhao, Huixian; Lu, Haibin; Mu, Xiaoqian; Hu, Jingjiang; Zhou, Xiaona; Xie, Chang Gen

    2016-01-01

    bZIP (basic leucine zipper) transcription factors coordinate plant growth and development and control responses to environmental stimuli. The genome of Chinese cabbage (Brassica rapa) encodes 136 putative bZIP transcription factors. The bZIP transcription factors in Brassica rapa (BrbZIP) are classified into 10 subfamilies. Phylogenetic relationship analysis reveals that subfamily A consists of 23 BrbZIPs. Two BrbZIPs within subfamily A, Bra005287 and Bra017251, display high similarity to ABI5 (ABA Insensitive 5). Expression of subfamily A BrbZIPs, like BrABI5a (Bra005287/BrbZIP14) and BrABI5b (Bra017251/BrbZIP13), are significantly induced by the plant hormone ABA. Subcellular localization assay reveal that both BrABI5a and BrABI5b have a nuclear localization. BrABI5a and BrABI5b could directly stimulate ABA Responsive Element-driven HIS (a HIS3 reporter gene, which confers His prototrophy) or LUC (LUCIFERASE) expression in yeast and Arabidopsis protoplast. Deletion of the bZIP motif abolished BrABI5a and BrABI5b transcriptional activity. The ABA insensitive phenotype of Arabidopsis abi5-1 is completely suppressed in transgenic lines expressing BrABI5a or BrABI5b. Overall, these results suggest that ABI5 orthologs, BrABI5a and BrABI5b, have key roles in ABA signalling in Chinese cabbage. PMID:27414644

  14. Genome-Wide Analysis of the bZIP Gene Family Identifies Two ABI5-Like bZIP Transcription Factors, BrABI5a and BrABI5b, as Positive Modulators of ABA Signalling in Chinese Cabbage.

    PubMed

    Bai, Yili; Zhu, Wenbo; Hu, Xiaochen; Sun, Congcong; Li, Yanlin; Wang, Dandan; Wang, Qinhu; Pei, Guoliang; Zhang, Yanfeng; Guo, Aiguang; Zhao, Huixian; Lu, Haibin; Mu, Xiaoqian; Hu, Jingjiang; Zhou, Xiaona; Xie, Chang Gen

    2016-01-01

    bZIP (basic leucine zipper) transcription factors coordinate plant growth and development and control responses to environmental stimuli. The genome of Chinese cabbage (Brassica rapa) encodes 136 putative bZIP transcription factors. The bZIP transcription factors in Brassica rapa (BrbZIP) are classified into 10 subfamilies. Phylogenetic relationship analysis reveals that subfamily A consists of 23 BrbZIPs. Two BrbZIPs within subfamily A, Bra005287 and Bra017251, display high similarity to ABI5 (ABA Insensitive 5). Expression of subfamily A BrbZIPs, like BrABI5a (Bra005287/BrbZIP14) and BrABI5b (Bra017251/BrbZIP13), are significantly induced by the plant hormone ABA. Subcellular localization assay reveal that both BrABI5a and BrABI5b have a nuclear localization. BrABI5a and BrABI5b could directly stimulate ABA Responsive Element-driven HIS (a HIS3 reporter gene, which confers His prototrophy) or LUC (LUCIFERASE) expression in yeast and Arabidopsis protoplast. Deletion of the bZIP motif abolished BrABI5a and BrABI5b transcriptional activity. The ABA insensitive phenotype of Arabidopsis abi5-1 is completely suppressed in transgenic lines expressing BrABI5a or BrABI5b. Overall, these results suggest that ABI5 orthologs, BrABI5a and BrABI5b, have key roles in ABA signalling in Chinese cabbage. PMID:27414644

  15. Association between olfactory receptor genes, eating behavior traits and adiposity: results from the Quebec Family Study.

    PubMed

    Choquette, Anne C; Bouchard, Luigi; Drapeau, Vicky; Lemieux, Simone; Tremblay, Angelo; Bouchard, Claude; Vohl, Marie-Claude; Pérusse, Louis

    2012-02-01

    Obesity is a major health problem that can be influenced by eating behaviors. Evidence suggests that the sensory properties of food influence eating behaviors and lead to overeating and overweight. A previous genome-wide linkage scan for eating behavior traits assessed with the Three-Factor Eating Questionnaire (cognitive dietary restraint, disinhibition and hunger) performed in the Quebec Family Study (QFS) revealed a quantitative trait locus for disinhibition on chromosome 19p13. This region encodes a cluster of seven olfactory receptor (OR) genes, including OR7D4, previously associated with odor perceptions. Direct sequencing of the OR7D4 gene revealed 16 sequence variants. Nine OR7D4 sequence variants with minor allele frequency (MAF)>1% as well as 100 SNPs spanning the cluster of OR genes on 19p13 were tested for association with age- and sex-adjusted eating behaviors as well as adiposity traits in 890 subjects. One OR7D4 sequence variant (rs2878329 G>A) showed evidence of association with reduced levels of adiposity (p=0.03), cognitive dietary restraint (p=0.05) and susceptibility to hunger (p=0.008). None of the OR7D4 SNPs was associated with disinhibition, but a SNP (rs2240927) in another OR gene (OR7E24) showed evidence of association (p=0.03). Another SNP in the OR7G3 gene (rs10414255) was also found to be associated with adiposity and eating behaviors. These results are the first to suggest that variations in human olfactory receptor genes can influence eating behaviors and adiposity. The associations reported in the present study should be interpreted with caution considering the number of tests performed and considered as potential new hypotheses about the effects OR polymorphisms on eating behaviors and obesity that need to be further explored in other populations.

  16. Killer Cell Immunoglobulin-Like Receptor (KIR) Genotype Distribution in Familial Mediterranean Fever (FMF) Patients

    PubMed Central

    Erken, Ertugrul; Ozturk, Ozlem Goruroglu; Kudas, Ozlem; Tas, Didem Arslan; Demirtas, Ahmet; Kibar, Filiz; Dinkci, Suzan; Erken, Eren

    2015-01-01

    Background Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disease predominantly affecting Mediterranean populations. The gene associated with FMF is the MEFV gene, which encodes for a protein called pyrin. Mutations of pyrin lead to uncontrolled attacks of inflammation, and subclinical inflammation continues during attack-free intervals. Killer cell immunoglobulin-like receptor (KIR) genes encode HLA class I receptors expressed by NK cells. The aim this study was to look for immunogenetic determinants in the pathogenesis of FMF and find out if KIR are related to susceptibility to disease or complications like renal amyloidosis. Material/Methods One hundred and five patients with FMF and 100 healthy individuals were involved in the study. Isolated DNA from peripheral blood was amplified by sequence specific PCR probes and analyzed by Luminex for KIR genotypes. Fisher Exact test was used to evaluate the variation of KIR gene distribution. Results All patients and healthy controls expressed the framework genes. An activator KIR gene, KIR2DS2, was significantly more frequent in FMF patients (p=0.036). Renal amyloidosis and presence of arthritis were not associated with KIR genes and genotype. KIR3DL1 gene was more common in patients with high serum CRP (p=0.016). Conclusions According to our findings, we suggest that presence of KIR2DS2, which is an activator gene for NK cell functions, might be related to the autoinflammation in FMF. The potential effect of KIR genes on amyloidosis and other clinical features requires studies with larger sample sizes. PMID:26574972

  17. Sorting nexin 6, a novel SNX, interacts with the transforming growth factor-beta family of receptor serine-threonine kinases.

    PubMed

    Parks, W T; Frank, D B; Huff, C; Renfrew Haft, C; Martin, J; Meng, X; de Caestecker, M P; McNally, J G; Reddi, A; Taylor, S I; Roberts, A B; Wang, T; Lechleider, R J

    2001-06-01

    Sorting nexins (SNX) comprise a family of proteins with homology to several yeast proteins, including Vps5p and Mvp1p, that are required for the sorting of proteins to the yeast vacuole. Human SNX1, -2, and -4 have been proposed to play a role in receptor trafficking and have been shown to bind to several receptor tyrosine kinases, including receptors for epidermal growth factor, platelet-derived growth factor, and insulin as well as the long form of the leptin receptor, a glycoprotein 130-associated receptor. We now describe a novel member of this family, SNX6, which interacts with members of the transforming growth factor-beta family of receptor serine-threonine kinases. These receptors belong to two classes: type II receptors that bind ligand, and type I receptors that are subsequently recruited to transduce the signal. Of the type II receptors, SNX6 was found to interact strongly with ActRIIB and more moderately with wild type and kinase-defective mutants of TbetaRII. Of the type I receptors, SNX6 was found to interact only with inactivated TbetaRI. SNXs 1-4 also interacted with the transforming growth factor-beta receptor family, showing different receptor preferences. Conversely, SNX6 behaved similarly to the other SNX proteins in its interactions with receptor tyrosine kinases. Strong heteromeric interactions were also seen among SNX1, -2, -4, and -6, suggesting the formation in vivo of oligomeric complexes. These findings are the first evidence for the association of the SNX family of molecules with receptor serine-threonine kinases.

  18. GPR109A, GPR109B and GPR81, a family of hydroxy-carboxylic acid receptors.

    PubMed

    Ahmed, Kashan; Tunaru, Sorin; Offermanns, Stefan

    2009-11-01

    G-protein-coupled receptors (GPCRs) are the most versatile receptor family as they have the ability to respond to chemically diverse ligands. Despite intensive efforts during the past two decades, there are still more than 100 orphan GPCRs for which endogenous ligands are unknown. Recently, GPR109A, GPR109B and GPR81, which form a GPCR subfamily, have been deorphanized. The physiological ligands of these receptors are the ketone body 3-hydroxy-butyrate, the metabolite 2-hydroxy-propanoate (lactate) as well as the beta-oxidation intermediate 3-hydroxy-octanoate. Thus, this receptor subfamily is activated by hydroxy-carboxylic acid ligands which are intermediates of energy metabolism. All three receptors are predominantly expressed in adipocytes and mediate antilipolytic effects. In this article, we propose that the hydroxy-carboxylic acid structure of their endogenous ligands is the defining property of this receptor subfamily and that hydroxy-carboxylic acid receptors function as metabolic sensors which fine-tune the regulation of metabolic pathways.

  19. A large deletion/insertion-induced frameshift mutation of the androgen receptor gene in a family with a familial complete androgen insensitivity syndrome.

    PubMed

    Cong, Peikuan; Ye, Yinghui; Wang, Yue; Lu, Lingping; Yong, Jing; Yu, Ping; Joseph, Kimani Kagunda; Jin, Fan; Qi, Ming

    2012-06-01

    Androgen insensitivity syndrome (AIS) is an X-linked recessive genetic disorder with a normal 46, XY karyotype caused by abnormality of the androgen receptor (AR) gene. One Chinese family consisting of the proband and 5 other members with complete androgen insensitivity syndrome (CAIS) was investigated. Mutation analysis by DNA sequencing on all 8 exons and flanking intron regions of the AR gene revealed a unique large deletion/insertion mutation in the family. A 287 bp deletion and 77 bp insertion (c.933_1219delins77) mutation at codon 312 resulted in a frameshift which caused a premature stop (p.Phe312Aspfs*7) of polypeptide formation. The proband's mother and grandmother were heterozygous for the mutant allele. The proband's father, uncle and grandfather have the normal allele. From the pedigree constructed from mutational analysis of the family, it is revealed that the probably pathogenic mutation comes from the maternal side.

  20. Diversity and Inter-Connections in the CXCR4 Chemokine Receptor/Ligand Family: Molecular Perspectives

    PubMed Central

    Pawig, Lukas; Klasen, Christina; Weber, Christian; Bernhagen, Jürgen; Noels, Heidi

    2015-01-01

    CXCR4 and its ligand CXCL12 mediate the homing of progenitor cells in the bone marrow and their recruitment to sites of injury, as well as affect processes such as cell arrest, survival, and angiogenesis. CXCL12 was long thought to be the sole CXCR4 ligand, but more recently the atypical chemokine macrophage migration inhibitory factor (MIF) was identified as an alternative, non-cognate ligand for CXCR4 and shown to mediate chemotaxis and arrest of CXCR4-expressing T-cells. This has complicated the understanding of CXCR4-mediated signaling and associated biological processes. Compared to CXCL12/CXCR4-induced signaling, only few details are known on MIF/CXCR4-mediated signaling and it remains unclear to which extent MIF and CXCL12 reciprocally influence CXCR4 binding and signaling. Furthermore, the atypical chemokine receptor 3 (ACKR3) (previously CXCR7) has added to the complexity of CXCR4 signaling due to its ability to bind CXCL12 and MIF, and to evoke CXCL12- and MIF-triggered signaling independently of CXCR4. Also, extracellular ubiquitin (eUb) and the viral protein gp120 (HIV) have been reported as CXCR4 ligands, whereas viral chemokine vMIP-II (Herpesvirus) and human β3-defensin (HBD-3) have been identified as CXCR4 antagonists. This review will provide insight into the diversity and inter-connections in the CXCR4 receptor/ligand family. We will discuss signaling pathways initiated by binding of CXCL12 vs. MIF to CXCR4, elaborate on how ACKR3 affects CXCR4 signaling, and summarize biological functions of CXCR4 signaling mediated by CXCL12 or MIF. Also, we will discuss eUb and gp120 as alternative ligands for CXCR4, and describe vMIP-II and HBD-3 as antagonists for CXCR4. Detailed insight into biological effects of CXCR4 signaling und underlying mechanisms, including diversity of CXCR4 ligands and inter-connections with other (chemokine) receptors, is clinically important, as the CXCR4 antagonist AMD3100 has been approved as stem cell mobilizer in specific

  1. Parathyroid hormone induces the Nrna family of nuclear orphan receptors in vivo

    SciTech Connect

    Pirih, Flavia Q. . E-mail: fqpirih@ucla.edu; Aghaloo, Tara L. . E-mail: taghaloo@ucla.edu; Bezouglaia, Olga . E-mail: obezougl@ucla.edu; Nervina, Jeanne M. . E-mail: jnervina@ucla.edu; Tetradis, Sotirios; E-mail: sotirist@dent.ucla.edu

    2005-07-01

    Parathyroid hormone (PTH) has both anabolic and catabolic effects on bone metabolism, although the molecular mechanisms mediating these effects are largely unknown. Among the transcription factors induced by Pth in osteoblasts are the nerve growth factor-inducible factor B (NR4A; NGFI-B) family of orphan nuclear receptors: Nurr1, Nur77, and NOR-1. PTH induces NR4A members through the cAMP-protein kinase A (PKA) pathway in vitro. We report here that PTH rapidly and transiently induced expression of all three NR4A genes in PTH-target tissues in vivo. In calvaria, long bones, and kidneys, NR4A induction was maximal 0.5-1 h after a single intraperitoneal (i.p.) injection of 80 {mu}g/kg PTH. Nur77 demonstrated the highest expression, followed, in order, by Nurr1 and NOR-1. In calvaria and long bone, PTH-induced expression of each NR4A gene was detectable at 10 {mu}g/kg i.p. with maximum induction at 40-80 {mu}g/kg. PTH (3-34) did not induce NR4A mRNA levels in calvaria, long bone, and kidney in vivo, confirming our in vitro results that NR4A genes are induced primarily through the cAMP-PKA pathway. The magnitude of PTH-induced NR4A expression was comparable in vivo and in vitro. However, NR4A mRNA levels peaked and returned to baseline faster in vivo. Both in vivo and in vitro, PTH induced NR4A pre-mRNA levels suggesting that induction of these genes is, at least in part, through activation of mRNA synthesis. The in vivo induction of the NR4A family members by PTH suggests their involvement in, at least some, PTH-induced changes in bone metabolism.

  2. Structure-function relationships of peptides forming the calcin family of ryanodine receptor ligands.

    PubMed

    Xiao, Liang; Gurrola, Georgina B; Zhang, Jing; Valdivia, Carmen R; SanMartin, Mario; Zamudio, Fernando Z; Zhang, Liming; Possani, Lourival D; Valdivia, Héctor H

    2016-05-01

    Calcins are a novel family of scorpion peptides that bind with high affinity to ryanodine receptors (RyRs) and increase their activity by inducing subconductance states. Here, we provide a comprehensive analysis of the structure-function relationships of the eight calcins known to date, based on their primary sequence, three-dimensional modeling, and functional effects on skeletal RyRs (RyR1). Primary sequence alignment and evolutionary analysis show high similarity among all calcins (≥78.8% identity). Other common characteristics include an inhibitor cysteine knot (ICK) motif stabilized by three pairs of disulfide bridges and a dipole moment (DM) formed by positively charged residues clustering on one side of the molecule and neutral and negatively charged residues segregating on the opposite side. [(3)H]Ryanodine binding assays, used as an index of the open probability of RyRs, reveal that all eight calcins activate RyR1 dose-dependently with Kd values spanning approximately three orders of magnitude and in the following rank order: opicalcin1 > opicalcin2 > vejocalcin > hemicalcin > imperacalcin > hadrucalcin > maurocalcin > urocalcin. All calcins significantly augment the bell-shaped [Ca(2+)]-[(3)H]ryanodine binding curve with variable effects on the affinity constants for Ca(2+) activation and inactivation. In single channel recordings, calcins induce the appearance of a subconductance state in RyR1 that has a unique fractional value (∼20% to ∼60% of the full conductance state) but bears no relationship to binding affinity, DM, or capacity to stimulate Ca(2+) release. Except for urocalcin, all calcins at 100 nM concentration stimulate Ca(2+) release and deplete Ca(2+) load from skeletal sarcoplasmic reticulum. The natural variation within the calcin family of peptides offers a diversified set of high-affinity ligands with the capacity to modulate RyRs with high dynamic range and potency. PMID:27114612

  3. Structure–function relationships of peptides forming the calcin family of ryanodine receptor ligands

    PubMed Central

    Xiao, Liang; Gurrola, Georgina B.; Zhang, Jing; Valdivia, Carmen R.; SanMartin, Mario; Zamudio, Fernando Z.; Zhang, Liming; Possani, Lourival D.

    2016-01-01

    Calcins are a novel family of scorpion peptides that bind with high affinity to ryanodine receptors (RyRs) and increase their activity by inducing subconductance states. Here, we provide a comprehensive analysis of the structure–function relationships of the eight calcins known to date, based on their primary sequence, three-dimensional modeling, and functional effects on skeletal RyRs (RyR1). Primary sequence alignment and evolutionary analysis show high similarity among all calcins (≥78.8% identity). Other common characteristics include an inhibitor cysteine knot (ICK) motif stabilized by three pairs of disulfide bridges and a dipole moment (DM) formed by positively charged residues clustering on one side of the molecule and neutral and negatively charged residues segregating on the opposite side. [3H]Ryanodine binding assays, used as an index of the open probability of RyRs, reveal that all eight calcins activate RyR1 dose-dependently with Kd values spanning approximately three orders of magnitude and in the following rank order: opicalcin1 > opicalcin2 > vejocalcin > hemicalcin > imperacalcin > hadrucalcin > maurocalcin >> urocalcin. All calcins significantly augment the bell-shaped [Ca2+]-[3H]ryanodine binding curve with variable effects on the affinity constants for Ca2+ activation and inactivation. In single channel recordings, calcins induce the appearance of a subconductance state in RyR1 that has a unique fractional value (∼20% to ∼60% of the full conductance state) but bears no relationship to binding affinity, DM, or capacity to stimulate Ca2+ release. Except for urocalcin, all calcins at 100 nM concentration stimulate Ca2+ release and deplete Ca2+ load from skeletal sarcoplasmic reticulum. The natural variation within the calcin family of peptides offers a diversified set of high-affinity ligands with the capacity to modulate RyRs with high dynamic range and potency. PMID:27114612

  4. Exome Sequence Data From Multigenerational Families Implicate AMPA Receptor Trafficking in Neurocognitive Impairment and Schizophrenia Risk.

    PubMed

    Kos, Mark Z; Carless, Melanie A; Peralta, Juan; Blackburn, August; Almeida, Marcio; Roalf, David; Pogue-Geile, Michael F; Prasad, Konasale; Gur, Ruben C; Nimgaonkar, Vishwajit; Curran, Joanne E; Duggirala, Ravi; Glahn, David C; Blangero, John; Gur, Raquel E; Almasy, Laura

    2016-03-01

    Schizophrenia is a mental disorder characterized by impairments in behavior, thought, and neurocognitive performance. We searched for susceptibility loci at a quantitative trait locus (QTL) previously reported for abstraction and mental flexibility (ABF), a cognitive function often compromised in schizophrenia patients and their unaffected relatives. Exome sequences were determined for 134 samples in 8 European American families from the original linkage study, including 25 individuals with schizophrenia or schizoaffective disorder. At chromosome 5q32-35.3, we analyzed 407 protein-altering variants for association with ABF and schizophrenia status. For replication, significant, Bonferroni-corrected findings were tested against cognitive traits in Mexican American families (n = 959), as well as interrogated for schizophrenia risk using GWAS results from the Psychiatric Genomics Consortium (PGC). From the gene SYNPO, rs6579797 (MAF = 0.032) shows significant associations with ABF (P = .015) and schizophrenia (P = .040), as well as jointly (P = .0027). In the Mexican American pedigrees, rs6579797 exhibits significant associations with IQ (P = .011), indicating more global effects on neurocognition. From the PGC results, other SYNPO variants were identified with near significant effects on schizophrenia risk, with a local linkage disequilibrium block displaying signatures of positive selection. A second missense variant within the QTL, rs17551608 (MAF = 0.19) in the gene WWC1, also displays a significant effect on schizophrenia in our exome sequences (P = .038). Remarkably, the protein products of SYNPO and WWC1 are interaction partners involved in AMPA receptor trafficking, a brain process implicated in synaptic plasticity. Our study reveals variants in these genes with significant effects on neurocognition and schizophrenia risk, identifying a potential pathogenic mechanism for schizophrenia spectrum disorders. PMID:26405221

  5. N-terminal {beta}{sub 2}-adrenergic receptor polymorphisms do not correlate with bronchodilator response in asthma families

    SciTech Connect

    Holyroyd, K.J.; Dragwa, C.; Xu, J.

    1994-09-01

    Family and twin studies have suggested that susceptibility to asthma is inherited. One clinically relevant phenotype in asthma is the bronchodilator response to beta adrenergic therapy (reversibility) which may also be inherited and vary among asthmatics. Two polymorphisms of the {beta}{sub 2}-adrenergic receptor common to both asthmatic and normal individuals have been reported. One polymorphism, an amino acid polymorphism at position 16, correlated in one study with the need for long-term corticosteriod use in a population of asthmatics. It is conceivable that the increased use of corticosteroids needed to control symptoms in these patients may be explained by a decreased responsiveness to brochodilators mediated through this amino acid polymorphism in the {beta}{sub 2}-adrenergic receptor. However, the response to {beta}{sub 2} bronchodilators was not tested in these patients. In our Dutch asthma families, DNA sequencing of the {beta}{sub 2}-adrenergic receptor has been performed for N-terminal polymorphisms at amino acid positions 16 and 27 in over 100 individuals, and no correlation was found with the increase of FEV{sub 1} in response to bronchodilator. Linkage analysis between bronchodilator response and marker D5S412 near the {beta}{sub 2}-adrenergic receptor gene was performed in 286 sibpairs from these families. Using a bronchodilator response of >10% in FEV{sub 1} as a qualitative definition of affected individuals, there were 145 unaffected sibpairs, 121 sibpairs where one was affected, and 20 in which both were affected. Linear regression analysis of these sibpair data suggested possible linkage (p=0.007). This supports further examination of the {beta}{sub 2}-adrenergic receptor and its regulatory regions for polymorphisms that correlate with the bronchodilator response in asthma families.

  6. International Union of Basic and Clinical Pharmacology. XCIII. The Parathyroid Hormone Receptors—Family B G Protein–Coupled Receptors

    PubMed Central

    Vilardaga, Jean-Pierre

    2015-01-01

    The type-1 parathyroid hormone receptor (PTHR1) is a family B G protein–coupled receptor (GPCR) that mediates the actions of two polypeptide ligands; parathyroid hormone (PTH), an endocrine hormone that regulates the levels of calcium and inorganic phosphate in the blood by acting on bone and kidney, and PTH-related protein (PTHrP), a paracrine-factor that regulates cell differentiation and proliferation programs in developing bone and other tissues. The type-2 parathyroid hormone receptor (PTHR2) binds a peptide ligand, called tuberoinfundibular peptide-39 (TIP39), and while the biologic role of the PTHR2/TIP39 system is not as defined as that of the PTHR1, it likely plays a role in the central nervous system as well as in spermatogenesis. Mechanisms of action at these receptors have been explored through a variety of pharmacological and biochemical approaches, and the data obtained support a basic “two-site” mode of ligand binding now thought to be used by each of the family B peptide hormone GPCRs. Recent crystallographic studies on the family B GPCRs are providing new insights that help to further refine the specifics of the overall receptor architecture and modes of ligand docking. One intriguing pharmacological finding for the PTHR1 is that it can form surprisingly stable complexes with certain PTH/PTHrP ligand analogs and thereby mediate markedly prolonged cell signaling responses that persist even when the bulk of the complexes are found in internalized vesicles. The PTHR1 thus appears to be able to activate the Gαs/cAMP pathway not only from the plasma membrane but also from the endosomal domain. The cumulative findings could have an impact on efforts to develop new drug therapies for the PTH receptors. PMID:25713287

  7. Characterization of two patched receptors for the vertebrate hedgehog protein family

    PubMed Central

    Carpenter, David; Stone, Donna M.; Brush, Jennifer; Ryan, Anne; Armanini, Mark; Frantz, Gretchen; Rosenthal, Arnon; de Sauvage, Frederic J.

    1998-01-01

    The multitransmembrane protein Patched (PTCH) is the receptor for Sonic Hedgehog (Shh), a secreted molecule implicated in the formation of embryonic structures and in tumorigenesis. Current models suggest that binding of Shh to PTCH prevents the normal inhibition of the seven-transmembrane-protein Smoothened (SMO) by PTCH. According to this model, the inhibition of SMO signaling is relieved after mutational inactivation of PTCH in the basal cell nevus syndrome. Recently, PTCH2, a molecule with sequence homology to PTCH, has been identified. To characterize both PTCH molecules with respect to the various Hedgehog proteins, we have isolated the human PTCH2 gene. Biochemical analysis of PTCH and PTCH2 shows that they both bind to all hedgehog family members with similar affinity and that they can form a complex with SMO. However, the expression patterns of PTCH and PTCH2 do not fully overlap. While PTCH is expressed throughout the mouse embryo, PTCH2 is found at high levels in the skin and in spermatocytes. Because Desert Hedgehog (Dhh) is expressed specifically in the testis and is required for germ cell development, it is likely that PTCH2 mediates its activity in vivo. Chromosomal localization of PTCH2 places it on chromosome 1p33–34, a region deleted in some germ cell tumors, raising the possibility that PTCH2 may be a tumor suppressor in Dhh target cells. PMID:9811851

  8. Genetic functions of the NAIP family of inflammasome receptors for bacterial ligands in mice.

    PubMed

    Zhao, Yue; Shi, Jianjin; Shi, Xuyan; Wang, Yupeng; Wang, Fengchao; Shao, Feng

    2016-05-01

    Biochemical studies suggest that the NAIP family of NLR proteins are cytosolic innate receptors that directly recognize bacterial ligands and trigger NLRC4 inflammasome activation. In this study, we generated Naip5(-/-), Naip1(-/-), and Naip2(-/-) mice and showed that bone marrow macrophages derived from these knockout mice are specifically deficient in detecting bacterial flagellin, the type III secretion system needle, and the rod protein, respectively. Naip1(-/-), Naip2(-/-), and Naip5(-/-) mice also resist lethal inflammasome activation by the corresponding ligand. Furthermore, infections performed in the Naip-deficient macrophages have helped to define the major signal in Legionella pneumophila, Salmonella Typhimurium and Shigella flexneri that is detected by the NAIP/NLRC4 inflammasome. Using an engineered S. Typhimurium infection model, we demonstrate the critical role of NAIPs in clearing bacterial infection and protecting mice from bacterial virulence-induced lethality. These results provide definitive genetic evidence for the important physiological function of NAIPs in antibacterial defense and inflammatory damage-induced lethality in mice. PMID:27114610

  9. The oxytocin/vasopressin receptor family has at least five members in the gnathostome lineage, inclucing two distinct V2 subtypes.

    PubMed

    Ocampo Daza, Daniel; Lewicka, Michalina; Larhammar, Dan

    2012-01-01

    The vertebrate oxytocin and vasopressin receptors form a family of G-protein-coupled receptors (GPCRs) that mediate a large variety of functions, including social behavior and the regulation of blood pressure, water balance and reproduction. In mammals four family members have been identified, three of which respond to vasopressin (VP) named V1A, V1B and V2, and one of which is activated by oxytocin (OT), called the OT receptor. Four receptors have been identified in chicken as well, but these have received different names. Until recently only V1-type receptors have been described in several species of teleost fishes. We have identified family members in several gnathostome genomes and performed phylogenetic analyses to classify OT/VP-receptors across species and determine orthology relationships. Our phylogenetic tree identifies five distinct ancestral gnathostome receptor subtypes in the OT/VP receptor family: V1A, V1B, V2A, V2B and OT receptors. The existence of distinct V2A and V2B receptors has not been previously recognized. We have found these two subtypes in all examined teleost genomes as well as in available frog and lizard genomes and conclude that the V2A-type is orthologous to mammalian V2 receptors whereas the V2B-type is orthologous to avian V2 receptors. Some teleost fishes have acquired additional and more recent gene duplicates with up to eight receptor family members. Thus, this analysis reveals an unprecedented complexity in the gnathostome repertoire of OT/VP receptors, opening interesting research avenues regarding functions such as regulation of water balance, reproduction and behavior, particularly in reptiles, amphibians, teleost fishes and cartilaginous fishes. PMID:22057000

  10. Conformationally constrained opioid ligands: the Dmt-Aba and Dmt-Aia versus Dmt-Tic scaffold.

    PubMed

    Ballet, Steven; Feytens, Debby; Wachter, Rien De; Vlaeminck, Magali De; Marczak, Ewa D; Salvadori, Severo; Graaf, Chris de; Rognan, Didier; Negri, Lucia; Lattanzi, Roberta; Lazarus, Lawrence H; Tourwé, Dirk; Balboni, Gianfranco

    2009-01-15

    Replacement of the constrained phenylalanine analogue 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) in the opioid Dmt-Tic-Gly-NH-Bn scaffold by the 4-amino-1,2,4,5-tetrahydro-indolo[2,3-c]azepin-3-one (Aia) and 4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one (Aba) scaffolds has led to the discovery of novel potent mu-selective agonists (Structures 5 and 12) as well as potent and selective delta-opioid receptor antagonists (Structures 9 and 15). Both stereochemistry and N-terminal N,N-dimethylation proved to be crucial factors for opioid receptor selectivity and functional bioactivity in the investigated small peptidomimetic templates. In addition to the in vitro pharmacological evaluation, automated docking models of Dmt-Tic and Dmt-Aba analogues were constructed in order to rationalize the observed structure-activity data.

  11. The induction of free proline accumulation by endogenous ABA in Arabidopsis thaliana during drought

    SciTech Connect

    Gottlieb, M.L.; Bray, E.A. )

    1991-05-01

    Endogenous levels of abscisic acid (ABA) and free proline increase in response to drought stress. Exogenous ABA has been shown to induce proline accumulation, suggesting that ABA triggers the amino acid response. To determine if endogenous ABA induces free proline accumulation, increases in ABA and proline during drought stress were compared between wild type (WT), ABA-insensitive (abi) and ABA-deficient (aba) mutants of Arabidopsis thaliana. If elevated levels of endogenous ABA signal the proline response, then the mutants would not be expected to accumulate proline during stress. abi should be unable to respond to increased levels of endogenous ABA, while aba should be unable to accumulate sufficient ABA to elicit a proline response. Drought-stressed three week old shoots of WT, abi, and aba exhibited different patterns of endogenous ABA accumulation, but similar patterns of proline accumulation over 24 hours. Although the patterns of endogenous ABA accumulation differed, maximum levels were similar in WT and abi, but aba produced approximately 25% less. However, free proline accumulated in all three plant lines. abi exhibited a greater, more rapid increase in free proline over that in either WT or aba. aba, however, showed the same pattern and levels of accumulation as that in WT. Since free proline accumulated to at least similar levels in both WT and mutants, regardless of the levels of ABA accumulation, it may be that only a small endogenous ABA accumulation is required for proline accumulation. Alternatively, endogenous ABA may not be the direct signal for the proline response during drought stress.

  12. Identification of a novel germline missense mutation of the androgen receptor in African American men with familial prostate cancer

    PubMed Central

    Hu, Si-Yi; Liu, Tao; Liu, Zhen-Zhen; Ledet, Elisa; Velasco-Gonzalez, Cruz; Mandal, Diptasri M; Koochekpour, Shahriar

    2010-01-01

    Race, family history and age are the unequivocally accepted risk factors for prostate cancer (PCa). Androgen receptor (AR)-dependent signaling is an important element in prostate carcinogenesis and its progression to metastatic disease. We examined the possibility of genomic changes in the AR in association with familial PCa in African Americans who have a higher incidence and mortality rate and a clinically more aggressive disease presentation than Caucasians. Genomic DNAs of 60 patients from 30 high-risk African American and Caucasian families participating in the Louisiana State University Health Sciences Center genetic linkage study of PCa were studied. Exon-specific polymerase-chain reaction, bi-directional automated sequencing and restriction enzyme genotyping were used to analyze for mutations in the coding region of the AR gene. We identified a germline AR (A1675T) (T559S) substitution mutation in the DNA-binding domain in three PCa-affected members of an African-American family with a history of early-onset disease. The present study describes the first AR germline mutation in an African-American family with a history of familial PCa. The AR (T559S) mutation may contribute to the disease by altering AR DNA-binding affinity and/or its response to androgens, non-androgenic steroids or anti-androgens. Additional studies will be required to define the frequency and contribution of the AR (A1675T) allele to early-onset and/or familial PCa in African Americans. PMID:20173765

  13. Deletion of exon 3 of the insulin receptor gene in a kindred with a familial form of insulin resistance

    SciTech Connect

    Wertheimer, E.; Barbetti, F.; Accili, D.; Taylor, S.I.; Litvin, Y.; Ebstein, R.P.; Bennet, E.R.

    1994-05-01

    Molecular scanning techniques, such as denaturing gradient gel electrophoresis (DGGE), greatly facilitate screening candidate genes for mutations. The authors have used DGGE to screen for mutations in the insulin receptor gene in a family in which four of five daughters were affected by type A insulin resistance in association with acanthosis nigricans and hyperandrogenism. DGGE did not detect mutations in any of the 22 exons of the insulin receptor gene. Nevertheless, Southern blot analysis suggested that there was a deletion of exon 3 in the other paternal allele of the insulin receptor gene. Analysis of the father`s cDNA confirmed that exon 3 was deleted from mRNA molecules derived from one of his two alleles of the insulin receptor gene. Furthermore, the father was found to be hemizygous for a polymorphic sequence (GAC{sup Asp} at codon 234) in exon 3 that was not inherited by any of the five daughters. Instead, all five daughters inherited the paternal allele with the deletion mutation. They did not detect mutations in the mother`s insulin receptor gene. Furthermore, the clinical syndrome did not segregate with either of the mother`s two alleles of the insulin receptor gene. Although the youngest daughter inherited the mutant allele from her father, she was not clinically affected. The explanation for the incomplete penetrance is not known. These results emphasize the importance of specifically searching for deletion mutations when screening candidate genes for mutations. Furthermore, the existence of apparently asymptomatic carriers of mutations in the insulin receptor gene, such as the father in the present study, suggests that the prevalence of mutations in the insulin receptor gene may be higher than would be predicted on the basis of the observed prevalence of patients with extreme insulin resistance. 34 refs., 6 figs., 1 tab.

  14. Familial acromegaly due to aryl hydrocarbon receptor-interacting protein (AIP) gene mutation in a Turkish cohort.

    PubMed

    Niyazoglu, Mutlu; Sayitoglu, Muge; Firtina, Sinem; Hatipoglu, Esra; Gazioglu, Nurperi; Kadioglu, Pinar

    2014-06-01

    Aryl hydrocarbon receptor-interacting protein (AIP) is associated with 15-20% of familial isolated pituitary adenomas and 50-80% of cases with AIP mutation exhibit a somatotropinoma. Herein we report clinical characteristics of a large family where AIP R304X variants have been identified. AIP mutation analysis was performed on a large (n = 52) Turkish family across six generations. Sella MRIs of 30 family members were obtained. Basal pituitary hormone levels were evaluated in 13 family members harboring an AIP mutation. Thirteen of 52 family members (25%) were found to have a heterozygous nonsense germline R304X mutation in the AIP gene. Seven of the 13 mutation carriers (53.8%) had current or previous history of pituitary adenoma. Of these 7 mutation carriers, all but one had somatotropinoma/somatolactotropinoma (85.7% of the pituitary adenomas). Of the 6 acromegaly patients with AIP mutation (F/M: 3/3) the mean age at diagnosis of acromegaly was 32 ± 10.3 years while the mean age of symptom onset was 24.8 ± 9.9 years. Three of the six (50%) acromegaly cases with AIP mutation within the family presented with a macroadenoma and none presented with gigantism. Biochemical disease control was achieved in 66.6% (4/6) of the mutation carriers with acromegaly after a mean follow-up period of 18.6 ± 17.6 years. Common phenotypic characteristics of familial pituitary adenoma or somatotropinoma due to AIP mutation vary between families or even between individuals within a family. PMID:23743763

  15. A novel member of the integrin receptor family mediates Arg-Gly-Asp- stimulated neutrophil phagocytosis

    PubMed Central

    1989-01-01

    Human neutrophils (PMN) express a heterodimeric receptor that has ligand binding specificity for the Arg-Gly-Asp (RGD) sequence within many adhesive proteins. A monoclonal antibody, B6H12, which binds to this receptor, inhibits both RGD-mediated ligand binding and stimulation of IgG-mediated phagocytosis by fibronectin, fibrinogen, vitronectin, von Willebrand's factor, and collagen type IV. By several criteria this receptor is neither a known very late antigen, a known cytoadhesin (gp IIb/IIIa-vitronectin receptor), nor a member of the LFA- 1, Mac-1, p150,95 group of integrin receptors. Ligand binding via this receptor is rapidly inactivated by products of the myeloperoxidase- hydrogen peroxide-halide system of PMN. We conclude that this receptor, for which we propose the name leukocyte response integrin, is a signal- transducing molecule on PMN which may have a significant early role in modulation of PMN function at inflammatory sites. PMID:2785522

  16. Modes of Action and Functions of ERECTA-family Receptor-like Kinases in Plant Organ Growth and Development

    SciTech Connect

    TORII, Keiko U.

    2012-05-01

    Higher plants constitute the central resource for renewable lignocellulose biomass that can supplement for the world's depleting stores of fossil fuels. As such, understanding the molecular and genetic mechanisms of plant organ growth will provide key knowledge and genetic resources that enables manipulation of plant biomass feedstock for better growth and productivity. The goal of this proposal is to understand how cell proliferation and growth are coordinated during aboveground organ morphogenesis, and how cell-cell signaling mediated by a family of receptor kinases coordinates plant organogenesis. The well-established model plant Arabidopsis thaliana is used for our research to facilitate rapid progress. Specifically, we focus on how ERECTA-family leucine-rich repeat receptor kinases (LRR-RLKs) interact in a synergistic manner to promote organogenesis and pattern formation in Arabidopsis. This project was highly successful, resulted in fourteen publications including nine peer-reviewed original research articles. One provisional US patent has been filed through this DOE funding. We have addressed the critical roles for a family of receptor kinases in coordinating proliferation and differentiation of plants, and we successfully elucidated the downstream targets of this signaling pathway in specifying stomatal patterning.

  17. [Considerations about study on mechanisms of thermal efficacies of moxibustion from activities of transient receptor potential family].

    PubMed

    Lu, Sheng-Feng; Yin, Hai-Yan; Tang, Yong; Zhang, Cheng-Shun; Yu, Mei-Ling; Luo, Ling; Yu, Shu-Guang

    2012-04-01

    Of the mammalian transient receptor potential (TRP) superfamily members, transient receptor potential vanilloid 1 (TRPV 1), TRPV 2,TRPV 3,TRPV 4,melastatin transient receptor potential (TRPM) 4, TRPM 5, and TRP ankyrin 1 (TRPA 1), are mostly permeable to both monovalent and divalent cation channels and are able to sense to changes of the temperature. Cutaneous TRPV 1, TRPV 2, TRPV 3, TRPV 4, TRPM 4 and TRPM 5 are sensitive to warm stimulation. Moxibustion, a type of physical thermal stimulus, can bring forth some curative effects after applying to certain acupoints for a period of time. Therefore, it is possible to reveal the underlying mechanisms of moxibustion in improving some related clinical disorders through studying activities of transient receptor potential family members. In the present paper, the authors summarize various characteristics of the activated TRP family members in the cutaneous tissue. Moreover, the authors also put forward some researching ideas about the local triggering mechanism of moxibustion stimulation and the resultant cascading effects by combining with its characters of local special responses in experimental studies.

  18. Prognostic roles for fibroblast growth factor receptor family members in malignant peripheral nerve sheath tumor

    PubMed Central

    Song, Fengju; Zheng, Hong; Chen, Kexin; Zhang, Wei; Yang, Jilong

    2016-01-01

    Background Malignant peripheral nerve sheath tumors (MPNST) are rare, highly malignant, and poorly understood sarcomas. The often poor outcome of MPNST highlights the necessity of identifying prognostic predictors for this aggressive sarcoma. Here, we investigate the role of fibroblast growth factor receptor (FGFR) family members in human MPNSTs. Results aCGH and bioinformatics analysis identified frequent amplification of the FGFR1 gene. FISH analysis revealed that 26.9% MPNST samples had amplification of FGFR1, with both focal and polysomy patterns observed. IHC identified that FGFR1 protein expression was positively correlated with FGFR1 gene amplification. High expression of FGFR1 protein was associated with better overall survival (OS) and was an independent prognostic predictor for OS of MPNST patients. Additionally, combined expression of FGFR1 and FGFR2 protein characterized a subtype of MPNST with better OS. FGFR4 protein was expressed 82.3% of MPNST samples, and was associated with poor disease-free survival. Materials and Methods We performed microarray-based comparative genomic hybridization (aCGH) profiling of two cohorts of primary MPNST tissue samples including 25 patients treated at The University of Texas MD Anderson Cancer Center and 26 patients from Tianjin Medical University Cancer Institute and Hospital. Fluorescence in situ hybridization (FISH) was used to validate the gene amplification detected by aCGH analysis. Another cohort of 63 formalin-fixed paraffin-embedded MPNST samples (including 52 samples for FISH assay) was obtained to explore FGFR1, 2, 3, and 4 protein expression by immunohistochemical (IHC) analysis. Conclusions Our integrated genomic and molecular studies provide evidence that FGFRs play different prognostic roles in MPNST. PMID:26993773

  19. Sex bias in copy number variation of olfactory receptor gene family depends on ethnicity.

    PubMed

    Shadravan, Farideh

    2013-01-01

    Gender plays a pivotal role in the human genetic identity and is also manifested in many genetic disorders particularly mental retardation. In this study its effect on copy number variation (CNV), known to cause genetic disorders was explored. As the olfactory receptor (OR) repertoire comprises the largest human gene family, it was selected for this study, which was carried out within and between three populations, derived from 150 individuals from the 1000 Genome Project. Analysis of 3872 CNVs detected among 791 OR loci, in which 307 loci showed CNV, revealed the following novel findings: Sex bias in CNV was significantly more prevalent in uncommon than common CNV variants of OR pseudogenes, in which the male genome showed more CNVs; and in one-copy number loss compared to complete deletion of OR pseudogenes; both findings implying a more recent evolutionary role for gender. Sex bias in copy number gain was also detected. Another novel finding was that the observed sex bias was largely dependent on ethnicity and was in general absent in East Asians. Using a CNV public database for sick children (International Standard Cytogenomic Array Consortium) the application of these findings for improving clinical molecular diagnostics is discussed by showing an example of sex bias in CNV among kids with autism. Additional clinical relevance is discussed, as the most polymorphic CNV-enriched OR cluster in the human genome, located on chr 15q11.2, is found near the Prader-Willi syndrome/Angelman syndrome bi-directionally imprinted region associated with two well-known mental retardation syndromes. As olfaction represents the primitive cognition in most mammals, arguably in competition with the development of a larger brain, the extensive retention of OR pseudogenes in females of this study, might point to a parent-of-origin indirect regulatory role for OR pseudogenes in the embryonic development of human brain. Thus any perturbation in the temporal regulation of olfactory

  20. Calcium signaling regulates trafficking of familial hypocalciuric hypercalcemia (FHH) mutants of the calcium sensing receptor.

    PubMed

    Grant, Michael P; Stepanchick, Ann; Breitwieser, Gerda E

    2012-12-01

    Calcium-sensing receptors (CaSRs) regulate systemic Ca(2+) homeostasis. Loss-of-function mutations cause familial benign hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism (NSHPT). FHH/NSHPT mutations can reduce trafficking of CaSRs to the plasma membrane. CaSR signaling is potentiated by agonist-driven anterograde CaSR trafficking, leading to a new steady state level of plasma membrane CaSR, which is maintained, with minimal functional desensitization, as long as extracellular Ca(2+) is elevated. This requirement for CaSR signaling to drive CaSR trafficking to the plasma membrane led us to reconsider the mechanism(s) contributing to dysregulated trafficking of FHH/NSHPT mutants. We simultaneously monitored dynamic changes in plasma membrane levels of CaSR and intracellular Ca(2+), using a chimeric CaSR construct, which allowed explicit tracking of plasma membrane levels of mutant or wild-type CaSRs in the presence of nonchimeric partners. Expression of mutants alone revealed severe defects in plasma membrane targeting and Ca(2+) signaling, which were substantially rescued by coexpression with wild-type CaSR. Biasing toward heterodimerization of wild-type and FHH/NSHPT mutants revealed that intracellular Ca(2+) oscillations were insufficient to rescue plasma membrane targeting. Coexpression of the nonfunctional mutant E297K with the truncation CaSRΔ868 robustly rescued trafficking and Ca(2+) signaling, whereas coexpression of distinct FHH/NSHPT mutants rescued neither trafficking nor signaling. Our study suggests that rescue of FHH/NSHPT mutants requires a steady state intracellular Ca(2+) response when extracellular Ca(2+) is elevated and argues that Ca(2+) signaling by wild-type CaSRs rescues FHH mutant trafficking to the plasma membrane.

  1. GEm-Related 5 (GER5), an ABA and stress-responsive GRAM domain protein regulating seed development and inflorescence architecture.

    PubMed

    Baron, Kevin N; Schroeder, Dana F; Stasolla, Claudio

    2014-06-01

    We have identified an abscisic acid (ABA) and stress-responsive GRAM (Glucosyltransferases, Rab-like GTPase activators and Myotubularins) domain protein GER5 (GEm-Related 5) closely related to GEM (GLABRA2 Expression Modulator), a novel regulator of cell division and cell fate determination in epidermal cells. A loss-of-function T-DNA line (ger5-2) and transgenic lines silencing (GER5(RNAi)) or overexpressing (GER5(OE)) GER5 displayed several defects in reproductive development affecting seed and embryo development. RNA in situ studies revealed GER5 and related GRAM genes (GEM and GEm-Related 1 (GER1)) have both overlapping and unique expression domains in male and female reproductive organs. Hormone immunolocalization experiments further indicate GER5 transcripts preferentially localize to reproductive tissues which accumulate ABA. Expression analysis revealed members of the GRAM family (GER5, GER1, GEM) display tissue-specific expression patterns and are responsive to phytohormones and abiotic stress, in addition to genetic lesions (aba1, aba2, ctr1) affecting ABA biosynthesis or ethylene signalling. Mature seeds of ger5-2 mutants also exhibit reduced sensitivity to ABA during seed germination assays. Microarray analysis of aborting and developing seeds isolated from ger5-2 mutants revealed underlying transcriptional changes in carbohydrate metabolism, hormone signalling and catabolic processes (e.g. protein degradation, autophagy). Taken together, our results indicate ABA-responsive GRAM genes play a novel role in regulating the reproductive development of plants, and raise intriguing questions regarding the functional relationship between members of the GRAM gene family.

  2. Functional Pairing of Class B1 Ligand-GPCR in Cephalochordate Provides Evidence of the Origin of PTH and PACAP/Glucagon Receptor Family

    PubMed Central

    On, Jason S.W.; Duan, Cumming; Chow, Billy K.C.; Lee, Leo T.O.

    2015-01-01

    Several hypotheses have been proposed regarding the origin and evolution of the secretin family of peptides and receptors. However, identification of homologous ligand–receptor pairs in invertebrates and vertebrates is difficult because of the low levels of sequence identity between orthologs of distant species. In this study, five receptors structurally related to the vertebrate class B1 G protein-coupled receptor (GPCR) family were characterized from amphioxus (Branchiostoma floridae). Phylogenetic analysis showed that they clustered with vertebrate parathyroid hormone receptors (PTHR) and pituitary adenylate cyclase-activating polypeptide (PACAP)/glucagon receptors. These PTHR-like receptors shared synteny with several PTH and PACAP/glucagon receptors identified in spotted gar, Xenopus, and human, indicating that amphioxus preserves the ancestral chordate genomic organization of these receptor subfamilies. According to recent data by Mirabeau and Joly, amphioxus also expresses putative peptide ligands including homologs of PTH (bfPTH1 and 2) and PACAP/GLUC-like peptides (bfPACAP/GLUCs) that may interact with these receptors. Functional analyses showed that bfPTH1 and bfPTH2 activated one of the amphioxus receptors (bf98C) whereas bfPACAP/GLUCs strongly interacted with bf95. In summary, our data confirm the presence of PTH and PACAP/GLUC ligand–receptor pairs in amphioxus, demonstrating that functional homologs of vertebrate PTH and PACAP/glucagon GPCR subfamilies arose before the cephalochordate divergence from the ancestor of tunicates and vertebrates. PMID:25841489

  3. Functional Pairing of Class B1 Ligand-GPCR in Cephalochordate Provides Evidence of the Origin of PTH and PACAP/Glucagon Receptor Family.

    PubMed

    On, Jason S W; Duan, Cumming; Chow, Billy K C; Lee, Leo T O

    2015-08-01

    Several hypotheses have been proposed regarding the origin and evolution of the secretin family of peptides and receptors. However, identification of homologous ligand-receptor pairs in invertebrates and vertebrates is difficult because of the low levels of sequence identity between orthologs of distant species. In this study, five receptors structurally related to the vertebrate class B1 G protein-coupled receptor (GPCR) family were characterized from amphioxus (Branchiostoma floridae). Phylogenetic analysis showed that they clustered with vertebrate parathyroid hormone receptors (PTHR) and pituitary adenylate cyclase-activating polypeptide (PACAP)/glucagon receptors. These PTHR-like receptors shared synteny with several PTH and PACAP/glucagon receptors identified in spotted gar, Xenopus, and human, indicating that amphioxus preserves the ancestral chordate genomic organization of these receptor subfamilies. According to recent data by Mirabeau and Joly, amphioxus also expresses putative peptide ligands including homologs of PTH (bfPTH1 and 2) and PACAP/GLUC-like peptides (bfPACAP/GLUCs) that may interact with these receptors. Functional analyses showed that bfPTH1 and bfPTH2 activated one of the amphioxus receptors (bf98C) whereas bfPACAP/GLUCs strongly interacted with bf95. In summary, our data confirm the presence of PTH and PACAP/GLUC ligand-receptor pairs in amphioxus, demonstrating that functional homologs of vertebrate PTH and PACAP/glucagon GPCR subfamilies arose before the cephalochordate divergence from the ancestor of tunicates and vertebrates.

  4. Functional Pairing of Class B1 Ligand-GPCR in Cephalochordate Provides Evidence of the Origin of PTH and PACAP/Glucagon Receptor Family.

    PubMed

    On, Jason S W; Duan, Cumming; Chow, Billy K C; Lee, Leo T O

    2015-08-01

    Several hypotheses have been proposed regarding the origin and evolution of the secretin family of peptides and receptors. However, identification of homologous ligand-receptor pairs in invertebrates and vertebrates is difficult because of the low levels of sequence identity between orthologs of distant species. In this study, five receptors structurally related to the vertebrate class B1 G protein-coupled receptor (GPCR) family were characterized from amphioxus (Branchiostoma floridae). Phylogenetic analysis showed that they clustered with vertebrate parathyroid hormone receptors (PTHR) and pituitary adenylate cyclase-activating polypeptide (PACAP)/glucagon receptors. These PTHR-like receptors shared synteny with several PTH and PACAP/glucagon receptors identified in spotted gar, Xenopus, and human, indicating that amphioxus preserves the ancestral chordate genomic organization of these receptor subfamilies. According to recent data by Mirabeau and Joly, amphioxus also expresses putative peptide ligands including homologs of PTH (bfPTH1 and 2) and PACAP/GLUC-like peptides (bfPACAP/GLUCs) that may interact with these receptors. Functional analyses showed that bfPTH1 and bfPTH2 activated one of the amphioxus receptors (bf98C) whereas bfPACAP/GLUCs strongly interacted with bf95. In summary, our data confirm the presence of PTH and PACAP/GLUC ligand-receptor pairs in amphioxus, demonstrating that functional homologs of vertebrate PTH and PACAP/glucagon GPCR subfamilies arose before the cephalochordate divergence from the ancestor of tunicates and vertebrates. PMID:25841489

  5. Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8'-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition.

    PubMed

    Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

    2013-03-01

    Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8'-hydroxyase gene which was highly expressed during seed development (TaABA8'OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8'OH1 on the D genome (TaABA8'OH1-D) was identified in Japanese cultivars including 'Tamaizumi'. However, a single mutation in TaABA8'OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8'OH1 on the A genome (TaABA8'OH1-A), TM1833, was identified from gamma-ray irradiation lines of 'Tamaizumi'. TM1833 (a double mutant in TaABA8'OH1-A and TaABA8'OH1-D) showed lower TaABA8'OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in 'Tamaizumi' (a single mutant in TaABA8'OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8'OH1 may be effective in germination inhibition in field-grown wheat.

  6. Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8′-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition

    PubMed Central

    Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

    2013-01-01

    Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8′-hydroxyase gene which was highly expressed during seed development (TaABA8′OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8′OH1 on the D genome (TaABA8′OH1-D) was identified in Japanese cultivars including ‘Tamaizumi’. However, a single mutation in TaABA8′OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8′OH1 on the A genome (TaABA8′OH1-A), TM1833, was identified from gamma-ray irradiation lines of ‘Tamaizumi’. TM1833 (a double mutant in TaABA8′OH1-A and TaABA8′OH1-D) showed lower TaABA8′OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in ‘Tamaizumi’ (a single mutant in TaABA8′OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8′OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

  7. cGMP-dependent ABA-induced stomatal closure in the ABA-insensitive Arabidopsis mutant abi1-1.

    PubMed

    Dubovskaya, Lyudmila V; Bakakina, Yulia S; Kolesneva, Ekaterina V; Sodel, Dmitry L; McAinsh, Martin R; Hetherington, Alistair M; Volotovski, Igor D

    2011-07-01

    • The drought hormone abscisic acid (ABA) is widely known to produce reductions in stomatal aperture in guard cells. The second messenger cyclic guanosine 3', 5'-monophosphate (cGMP) is thought to form part of the signalling pathway by which ABA induces stomatal closure. • We have examined the signalling events during cGMP-dependent ABA-induced stomatal closure in wild-type Arabidopsis plants and plants of the ABA-insensitive Arabidopsis mutant abi1-1. • We show that cGMP acts downstream of hydrogen peroxide (H(2) O(2) ) and nitric oxide (NO) in the signalling pathway by which ABA induces stomatal closure. H(2) O(2) - and NO-induced increases in the cytosolic free calcium concentration ([Ca(2+) ](cyt) ) were cGMP-dependent, positioning cGMP upstream of [Ca(2+) ](cyt) , and involved the action of the type 2C protein phosphatase ABI1. Increases in cGMP were mediated through the stimulation of guanylyl cyclase by H(2) O(2) and NO. We identify nucleoside diphosphate kinase as a new cGMP target protein in Arabidopsis. • This study positions cGMP downstream of ABA-induced changes in H(2) O(2) and NO, and upstream of increases in [Ca(2+) ](cyt) in the signalling pathway leading to stomatal closure.

  8. Transactivation of ErbB Family of Receptor Tyrosine Kinases Is Inhibited by Angiotensin-(1-7) via Its Mas Receptor

    PubMed Central

    Akhtar, Saghir; Chandrasekhar, Bindu; Attur, Sreeja; Dhaunsi, Gursev S.; Yousif, Mariam H. M.; Benter, Ibrahim F.

    2015-01-01

    Transactivation of the epidermal growth factor receptor (EGFR or ErbB) family members, namely EGFR and ErbB2, appears important in the development of diabetes-induced vascular dysfunction. Angiotensin-(1–7) [Ang-(1–7)] can prevent the development of hyperglycemia-induced vascular complications partly through inhibiting EGFR transactivation. Here, we investigated whether Ang-(1–7) can inhibit transactivation of ErbB2 as well as other ErbB receptors in vivo and in vitro. Streptozotocin-induced diabetic rats were chronically treated with Ang-(1–7) or AG825, a selective ErbB2 inhibitor, for 4 weeks and mechanistic studies performed in the isolated mesenteric vasculature bed as well as in cultured vascular smooth muscle cells (VSMCs). Ang-(1–7) or AG825 treatment inhibited diabetes-induced phosphorylation of ErbB2 receptor at tyrosine residues Y1221/22, Y1248, Y877, as well as downstream signaling via ERK1/2, p38 MAPK, ROCK, eNOS and IkB-α in the mesenteric vascular bed. In VSMCs cultured in high glucose (25 mM), Ang-(1–7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1–7). Ang-(1–7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors. Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1–7) that could be prevented by D-Pro7-Ang-(1–7) in VSMC. These data suggest that Ang-(1–7) via its Mas receptor acts as a pan-ErbB inhibitor and might represent a novel general mechanism by which Ang-(1–7) exerts its beneficial effects in many disease states including diabetes-induced vascular complications. PMID:26536590

  9. Transactivation of ErbB Family of Receptor Tyrosine Kinases Is Inhibited by Angiotensin-(1-7) via Its Mas Receptor.

    PubMed

    Akhtar, Saghir; Chandrasekhar, Bindu; Attur, Sreeja; Dhaunsi, Gursev S; Yousif, Mariam H M; Benter, Ibrahim F

    2015-01-01

    Transactivation of the epidermal growth factor receptor (EGFR or ErbB) family members, namely EGFR and ErbB2, appears important in the development of diabetes-induced vascular dysfunction. Angiotensin-(1-7) [Ang-(1-7)] can prevent the development of hyperglycemia-induced vascular complications partly through inhibiting EGFR transactivation. Here, we investigated whether Ang-(1-7) can inhibit transactivation of ErbB2 as well as other ErbB receptors in vivo and in vitro. Streptozotocin-induced diabetic rats were chronically treated with Ang-(1-7) or AG825, a selective ErbB2 inhibitor, for 4 weeks and mechanistic studies performed in the isolated mesenteric vasculature bed as well as in cultured vascular smooth muscle cells (VSMCs). Ang-(1-7) or AG825 treatment inhibited diabetes-induced phosphorylation of ErbB2 receptor at tyrosine residues Y1221/22, Y1248, Y877, as well as downstream signaling via ERK1/2, p38 MAPK, ROCK, eNOS and IkB-α in the mesenteric vascular bed. In VSMCs cultured in high glucose (25 mM), Ang-(1-7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1-7). Ang-(1-7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors. Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1-7) that could be prevented by D-Pro7-Ang-(1-7) in VSMC. These data suggest that Ang-(1-7) via its Mas receptor acts as a pan-ErbB inhibitor and might represent a novel general mechanism by which Ang-(1-7) exerts its beneficial effects in many disease states including diabetes-induced vascular complications. PMID:26536590

  10. Expression analysis of abscisic acid (ABA) and metabolic signalling factors in developing endosperm and embryo of barley☆

    PubMed Central

    Chen, Zhiwei; Huang, Jianhua; Muttucumaru, Nira; Powers, Stephen J.; Halford, Nigel G.

    2013-01-01

    The expression of genes encoding components of ABA and metabolic signalling pathways in developing barley endosperm and embryo was investigated. The genes included HvRCAR35_47387 and HvRCAR35_2538 (encoding ABA receptors), HvABI1d (protein phosphatase 2C), HvSnRK2.4, HvSnRK2.6 and HvPKABA1 (SnRK2-type protein kinases) and HvABI5 (ABA response element binding protein; AREBP), as well as two genes encoding SnRK1-type protein kinases. Both SnRK1 and SnRK2 phosphorylate AREBPs, but SnRK2 is activated by ABA whereas SnRK1 may be broken down. Multiple cereal AREBPs with two conserved SnRK1/2 target sites and another class of BZIP transcription factors with SnRK1/2 binding sites, including HvBLZ1, were identified. Barley grain (cv. Triumph) was sampled at 15, 20, 25 and 30 days post-anthesis (dpa). HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 were expressed highly in the endosperm but at much lower levels in the embryo. Conversely, HvPKABA1 and HvRCAR35_2538 were expressed at higher levels in the embryo than the endosperm, while HvSnRK2.6 was expressed at similar levels in both. HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 all peaked in expression in the endosperm at 20 dpa. A model is proposed in which ABA brings about a transition from a SnRK1-dominated state in the endosperm during grain filling to a SnRK2-dominated state during maturation. PMID:24748715

  11. Identification and functional analysis of olfactory receptor family reveal unusual characteristics of the olfactory system in the migratory locust.

    PubMed

    Wang, Zhifeng; Yang, Pengcheng; Chen, Dafeng; Jiang, Feng; Li, Yan; Wang, Xianhui; Kang, Le

    2015-11-01

    Locusts represent the excellent model of insect olfaction because the animals are equipped with an unusual olfactory system and display remarkable density-dependent olfactory plasticity. However, information regarding receptor molecules involved in the olfactory perception of locusts is very limited. On the basis of genome sequence and antennal transcriptome of the migratory locust, we conduct the identification and functional analysis of two olfactory receptor families: odorant receptors (ORs) and ionotropic receptors (IRs). In the migratory locust, there is an expansion of OR family (142 ORs) while distinctly lower number of IR genes (32 IRs) compared to the repertoires of other insects. The number of the locust OR genes is much less than that of glomeruli in antennal lobe, challenging the general principle of the "one glomerulus-one receptor" observed in other insects. Most OR genes are found in tandem arrays, forming two large lineage-specific subfamilies in the phylogenetic tree. The "divergent IR" subfamily displays a significant contraction, and most of the IRs belong to the "antennal IR" subfamily in the locust. Most ORs/IRs have olfactory-specific expression while some broadly- or internal-expressed members are also found. Differing from holometabolous insects, the migratory locust contains very similar expression profiles of ORs/IRs between nymph and adult stages. RNA interference and behavioral assays indicate that an OR-based signaling pathway, not IR-based, mediates the attraction of locusts to aggregation pheromones. These discoveries provide insights into the unusual olfactory system of locusts and enhance our understanding of the evolution of insect olfaction. PMID:26265180

  12. Identification and functional analysis of olfactory receptor family reveal unusual characteristics of the olfactory system in the migratory locust.

    PubMed

    Wang, Zhifeng; Yang, Pengcheng; Chen, Dafeng; Jiang, Feng; Li, Yan; Wang, Xianhui; Kang, Le

    2015-11-01

    Locusts represent the excellent model of insect olfaction because the animals are equipped with an unusual olfactory system and display remarkable density-dependent olfactory plasticity. However, information regarding receptor molecules involved in the olfactory perception of locusts is very limited. On the basis of genome sequence and antennal transcriptome of the migratory locust, we conduct the identification and functional analysis of two olfactory receptor families: odorant receptors (ORs) and ionotropic receptors (IRs). In the migratory locust, there is an expansion of OR family (142 ORs) while distinctly lower number of IR genes (32 IRs) compared to the repertoires of other insects. The number of the locust OR genes is much less than that of glomeruli in antennal lobe, challenging the general principle of the "one glomerulus-one receptor" observed in other insects. Most OR genes are found in tandem arrays, forming two large lineage-specific subfamilies in the phylogenetic tree. The "divergent IR" subfamily displays a significant contraction, and most of the IRs belong to the "antennal IR" subfamily in the locust. Most ORs/IRs have olfactory-specific expression while some broadly- or internal-expressed members are also found. Differing from holometabolous insects, the migratory locust contains very similar expression profiles of ORs/IRs between nymph and adult stages. RNA interference and behavioral assays indicate that an OR-based signaling pathway, not IR-based, mediates the attraction of locusts to aggregation pheromones. These discoveries provide insights into the unusual olfactory system of locusts and enhance our understanding of the evolution of insect olfaction.

  13. Structural basis for specificity of TGF[beta] family receptor small molecule inhibitors

    SciTech Connect

    Ogunjimi, Abiodun A.; Zeqiraj, Elton; Ceccarelli, Derek F.; Sicheri, Frank; Wrana, Jeffrey L.; David, Laurent

    2012-07-24

    Transforming growth factor-{beta} (TGF{beta}) receptor kinase inhibitors have a great therapeutic potential. SB431542 is one of the mainly used kinase inhibitors of the TGF{beta}/Activin pathway receptors, but needs improvement of its EC{sub 50} (EC{sub 50} = 1 {mu}M) to be translated to clinical use. A key feature of SB431542 is that it specifically targets receptors from the TGF{beta}/Activin pathway but not the closely related receptors from the bone morphogenic proteins (BMP) pathway. To understand the mechanisms of this selectivity, we solved the crystal structure of the TGF{beta} type I receptor (T{beta}RI) kinase domain in complex with SB431542. We mutated T{beta}RI residues coordinating SB431542 to their counterparts in activin-receptor like kinase 2 (ALK2), a BMP receptor kinase, and tested the kinase activity of mutated T{beta}RI. We discovered that a Ser280Thr mutation yielded a T{beta}RI variant that was resistant to SB431542 inhibition. Furthermore, the corresponding Thr283Ser mutation in ALK2 yielded a BMP receptor sensitive to SB431542. This demonstrated that Ser280 is the key determinant of selectivity for SB431542. This work provides a framework for optimising the SB431542 scaffold to more potent and selective inhibitors of the TGF{beta}/Activin pathway.

  14. Family.

    ERIC Educational Resources Information Center

    Hurst, Hunter, Ed.; And Others

    1985-01-01

    This document contains the fourth volume of "Today's Delinquent," an annual publication of the National Center for Juvenile Justice. This volume deals with the issue of the family and delinquency. "The Family and Delinquency" (LaMar T. Empey) systematically reviews and weighs the evidence to support prominent theories on the origins of…

  15. Identification of new ABA- and MEJA-activated sugarcane bZIP genes by data mining in the SUCEST database.

    PubMed

    Schlögl, Paulo Sérgio; Nogueira, Fábio Tebaldi S; Drummond, Rodrigo; Felix, Juliana M; De Rosa, Vicente E; Vicentini, Renato; Leite, Adilson; Ulian, Eugênio C; Menossi, Marcelo

    2008-02-01

    Sugarcane is generally propagated by cuttings of the stalk containing one or more lateral buds, which will develop into a new plant. The transition from the dormant into the active stage constitutes a complex phenomenon characterized by changes in accumulation of phytohormones and several other physiological aspects. Abscisic acid (ABA) and methyl-jasmonate (MeJA) are major signaling molecules, which influence plant development and stress responses. These plant regulators modulate gene expression with the participation of many transcriptional factors. Basic leucine zipper proteins (bZIPs) form a large family of transcriptional factors involved in a variety of plant physiological processes, such as development and responses to stress. Query sequences consisting of full-length protein sequence of each of the Arabidopsis bZIP families were utilized to screen the sugarcane EST database (SUCEST) and 86 sugarcane assembled sequences (SAS) coding for bZIPs were identified. cDNA arrays and RNA-gel blots were used to study the expression of these sugarcane bZIP genes during early plantlet development and in response to ABA and MeJA. Six bZIP genes were found to be differentially expressed during development. ABA and MeJA modulated the expression of eight sugarcane bZIP genes. Our findings provide novel insights into the expression of this large protein family of transcriptional factors in sugarcane.

  16. Skeletal receptors for steroid-family regulating glycoprotein hormones: A multilevel, integrated physiological control system.

    PubMed

    Blair, Harry C; Robinson, Lisa J; Sun, Li; Isales, Carlos; Davies, Terry F; Zaidi, Mone

    2011-12-01

    Pituitary glycoprotein hormone receptors, including ACTH-R, TSH-R, and FSH-R, occur in bone. Their skeletal expression reflects that central endocrine control is evolutionarily recent. ACTH receptors, in osteoblasts or the adrenal cortex, drive VEGF synthesis. VEGF is essential to maintain vasculature. In bone, ACTH suppression by glucocorticoids can cause osteonecrosis. TSH receptors occur on osteoblasts and osteoclasts, in both cases reducing activity. Thus, TSH directly reduces skeletal turnover, consistent with evolutionary adaptation to stress. FSH receptors accelerate bone resorption, whereas estrogen promotes bone formation, the forces usually balancing. With ovarian failure, low estrogen with high FSH causes rapid bone loss. The skeletal FSH effect in the menopause seems paradoxical, but it is a logical adaptation in lactation, where prolonged FSH elevation also occurs. In addition to receptors, there is some synthesis of pituitary glycoproteins at distributed sites; this is not well studied, but it may further modify the paradigm of central endocrine regulation.

  17. ABA flow modelling in Ricinus communis exposed to salt stress and variable nutrition

    PubMed Central

    Peuke, Andreas D.

    2016-01-01

    In a series of experiments with Ricinus communis, abscisic acid (ABA) concentrations in tissues and transport saps, its de novo biosynthesis, long-distance transport, and metabolism (degradation) were affected by nutritional conditions, nitrogen (N) source, and nutrient limitation, or salt stress. In the present study these data were statistically re-evaluated, and new correlations presented that underpin the importance of this universal phytohormone. The biggest differences in ABA concentration were observed in xylem sap. N source had the strongest effect; however, nutrient limitation (particularly phosphorus limitation) and salt also had significant effects. ABA was found in greater concentration in phloem sap compared with xylem sap; however, the effect of treatment on ABA concentration in phloem was lower. In the leaves, ABA concentration was most variable compared with the other tissues. This variation was only affected by the N source. In roots, ABA was significantly decreased by nutrient limitation. Of the compartments in which ABA was quantified, xylem sap ABA concentration was most significantly correlated with leaf stomatal conductance and leaf growth. Additionally, ABA concentration in xylem was significantly correlated to that in phloem, indicating a 6-fold concentration increase from xylem to phloem. The ABA flow model showed that biosynthesis of ABA in roots affected the xylem flow of ABA. Moreover, ABA concentration in xylem affected the degradation of the phytohormone in shoots and also its export from shoots via phloem. The role of phloem transport is discussed since it stimulates ABA metabolism in roots. PMID:27440939

  18. PSD-95 family MAGUKs are essential for anchoring AMPA and NMDA receptor complexes at the postsynaptic density

    PubMed Central

    Chen, Xiaobing; Levy, Jonathan M.; Hou, Austin; Winters, Christine; Azzam, Rita; Sousa, Alioscka A.; Leapman, Richard D.; Nicoll, Roger A.; Reese, Thomas S.

    2015-01-01

    The postsynaptic density (PSD)-95 family of membrane-associated guanylate kinases (MAGUKs) are major scaffolding proteins at the PSD in glutamatergic excitatory synapses, where they maintain and modulate synaptic strength. How MAGUKs underlie synaptic strength at the molecular level is still not well understood. Here, we explore the structural and functional roles of MAGUKs at hippocampal excitatory synapses by simultaneous knocking down PSD-95, PSD-93, and synapse-associated protein (SAP)102 and combining electrophysiology and transmission electron microscopic (TEM) tomography imaging to analyze the resulting changes. Acute MAGUK knockdown greatly reduces synaptic transmission mediated by α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (AMPARs) and N-methyl-d-aspartate receptors (NMDARs). This knockdown leads to a significant rise in the number of silent synapses, diminishes the size of PSDs without changes in pre- or postsynaptic membrane, and depletes the number of membrane-associated PSD-95–like vertical filaments and transmembrane structures, identified as AMPARs and NMDARs by EM tomography. The differential distribution of these receptor-like structures and dependence of their abundance on PSD size matches that of AMPARs and NMDARs in the hippocampal synapses. The loss of these structures following MAGUK knockdown tracks the reduction in postsynaptic AMPAR and NMDAR transmission, confirming the structural identities of these two types of receptors. These results demonstrate that MAGUKs are required for anchoring both types of glutamate receptors at the PSD and are consistent with a structural model where MAGUKs, corresponding to membrane-associated vertical filaments, are the essential structural proteins that anchor and organize both types of glutamate receptors and govern the overall molecular organization of the PSD. PMID:26604311

  19. Inactivation of the first nucleotide-binding fold of the sulfonylurea receptor, and familial persistent hyperinsulinemic hypoglycemia of infancy

    SciTech Connect

    Thomas, P.M.; Wohllk, N.; Huang, E.

    1996-09-01

    Familial persistent hyperinsulinemic hypoglycemia of infancy is a disorder of glucose homeostasis and is characterized by unregulated insulin secretion and profound hypoglycemia. Loss-of-function mutations in the second nucleotide-binding fold of the sulfonylurea receptor, a subunit of the pancreatic-islet {beta}-cell ATP-dependent potassium channel, has been demonstrated to be causative for persistent hyperinsulinemic hypoglycemia of infancy. We now describe three additional mutations in the first nucleotide-binding fold of the sulfonylurea-receptor gene. One point mutation disrupts the highly conserved Walker A motif of the first nucleotide-binding-fold region. The other two mutations occur in noncoding sequences required for RNA processing and are predicted to disrupt the normal splicing pathway of the sulfonylurea-receptor mRNA precursor. These data suggest that both nucleotide-binding-fold regions of the sulfortylurea receptor are required for normal regulation of {beta}-cell ATP-dependent potassium channel activity and insulin secretion. 32 refs., 4 figs., 1 tab.

  20. Reduced ABA Accumulation in the Root System is Caused by ABA Exudation in Upland Rice (Oryza sativa L. var. Gaoshan1) and this Enhanced Drought Adaptation.

    PubMed

    Shi, Lu; Guo, Miaomiao; Ye, Nenghui; Liu, Yinggao; Liu, Rui; Xia, Yiji; Cui, Suxia; Zhang, Jianhua

    2015-05-01

    Lowland rice (Nipponbare) and upland rice (Gaoshan 1) that are comparable under normal and moderate drought conditions showed dramatic differences in severe drought conditions, both naturally occurring long-term drought and simulated rapid water deficits. We focused on their root response and found that enhanced tolerance of upland rice to severe drought conditions was mainly due to the lower level of ABA in its roots than in those of the lowland rice. We first excluded the effect of ABA biosynthesis and catabolism on root-accumulated ABA levels in both types of rice by monitoring the expression of four OsNCED genes and two OsABA8ox genes. Next, we excluded the impact of the aerial parts on roots by suppressing leaf-biosynthesized ABA with fluridone and NDGA (nordihydroguaiaretic acid), and measuring the ABA level in detached roots. Instead, we proved that upland rice had the ability to export considerably more root-sourced ABA than lowland rice under severe drought, which improved ABA-dependent drought adaptation. The investigation of apoplastic pH in root cells and root anatomy showed that ABA leakage in the root system of upland rice was related to high apoplastic pH and the absence of Casparian bands in the sclerenchyma layer. Finally, taking some genes as examples, we predicted that different ABA levels in rice roots stimulated distinct ABA perception and signaling cascades, which influenced its response to water stress.

  1. The type I interferon receptor: structure, function, and evolution of a family business.

    PubMed

    Mogensen, K E; Lewerenz, M; Reboul, J; Lutfalla, G; Uzé, G

    1999-10-01

    Recent results indicate that coherent models of how multiple interferons (IFN) are recognized and signal selectively through a common receptor are now feasible. A proposal is made that the IFN receptor, with its subunits IFNAR-1 and IFNAR-2, presents two separate ligand binding sites, and this double structure is both necessary and sufficient to ensure that the different IFN are recognized and can act selectively. The key feature is the duplication of the extracellular domain of the IFNAR-1 subunit and the configurational geometry that this imposes on the intracellular domains of the receptor subunits and their associated tyrosine kinases. PMID:10547147

  2. The Plant-Specific SR45 Protein Negatively Regulates Glucose and ABA Signaling during Early Seedling Development in Arabidopsis1[W

    PubMed Central

    Carvalho, Raquel Fonseca; Carvalho, Sofia Domingues; Duque, Paula

    2010-01-01

    The plant-specific SR45 belongs to the highly conserved family of serine/arginine-rich (SR) proteins, which play key roles in precursor-mRNA splicing and other aspects of RNA metabolism. An Arabidopsis (Arabidopsis thaliana) loss-of-function mutant, sr45-1, displays pleiotropic phenotypes, such as defects in flower and leaf morphology, root growth, and flowering time. Here, we show that the sr45-1 mutation confers hypersensitivity to glucose (Glc) during early seedling growth in Arabidopsis. Unlike wild-type plants, the sr45-1 mutant displays impaired cotyledon greening and expansion as well as reduced hypocotyl elongation of dark-grown seedlings when grown in the presence of low (3%) Glc concentrations. In addition, SR45 is involved in the control of Glc-responsive gene expression, as the mutant displays enhanced repression of photosynthetic and nitrogen metabolism genes and overinduction of starch and anthocyanin biosynthesis genes. Like many other sugar response mutants, sr45-1 also shows hypersensitivity to abscisic acid (ABA) but appears to be unaffected in ethylene signaling. Importantly, the sr45-1 mutant shows enhanced ability to accumulate ABA in response to Glc, and the ABA biosynthesis inhibitor fluridone partially rescues the sugar-mediated growth arrest. Moreover, three ABA biosynthesis genes and two key ABA signaling genes, ABI3 and ABI5, are markedly overinduced by Glc in sr45-1. These results provide evidence that the SR45 protein defines a novel player in plant sugar response that negatively regulates Glc signaling during early seedling development by down-regulating both Glc-specific ABA accumulation and ABA biosynthesis and signaling gene expression. PMID:20699397

  3. Human Epidermal Growth Factor Receptor Family-Targeted Therapies in the Treatment of HER2-Overexpressing Breast Cancer

    PubMed Central

    Eroglu, Zeynep; Tagawa, Tomoko

    2014-01-01

    Breast cancer characterized by overexpression of human epidermal growth factor receptor 2 (HER2) has been associated with more aggressive disease progression and a poorer prognosis. Although an improved understanding of breast cancer pathogenesis and the role of HER2 signaling has resulted in significant survival improvements in the past 20 years, resistance to HER2-targeted therapy remains a concern. A number of strategies to prevent or overcome resistance to HER2-targeted therapy in breast cancer are being evaluated. This article provides a comprehensive review of (a) the role of HER2 signaling in breast cancer pathogenesis, (b) potential receptor and downstream therapeutic targets in breast cancer to overcome resistance to HER2-targeted therapy, and (c) clinical trials evaluating agents targeting one or more members of the HER family and/or downstream pathways for the treatment of breast cancer, with a focus on metastatic disease. PMID:24436312

  4. Ewing's sarcoma family tumors are sensitive to tumor necrosis factor-related apoptosis-inducing ligand and express death receptor 4 and death receptor 5.

    PubMed

    Mitsiades, N; Poulaki, V; Mitsiades, C; Tsokos, M

    2001-03-15

    In this study, we investigated the sensitivity of Ewing's sarcoma family tumors (ESFTs) of children and adolescents to the tumor necrosis factor-related apoptosis-inducing Ligand (TRAIL). TRAIL binds to death receptors (DRs) DR4, DR5, DcR1, and DcR2. Either DR4 or DR5 can induce apoptosis, whereas DcR1 and DcR2 are considered inhibitory receptors. Nine of 10 ESFT cell lines, including several that were Fas resistant, underwent apoptosis with TRAIL through activation of caspase-10, capase-8 (FLICE), caspase-3, and caspase-9. In contrast to the Fas signaling pathway, caspase-10, but not caspase-8 or the Fas-associated death domain-containing molecule, was recruited to the TRAIL receptor-associated signaling complex. We found that 9 of 10 ESFT cell lines expressed both DR4 and DR5 by Western blotting, whereas the TRAIL-resistant line expressed only DR4. However, DR4 was absent from the cell surface in the resistant and two additional lines (three of five tested lines), suggesting that it may have been nonfunctional. On the contrary, DR5 was located on the cell surface in all four sensitive lines tested, being absent only from the cell surface of the resistant line that was also DR5-negative by Western blotting. In agreement with these findings, the resistance of the line was overcome by restoration of DR5 levels by transfection. Levels of DcR1 and DcR2 or levels of the FLICE-inhibitory protein (FLIP) did not correlate with TRAIL resistance, and protein synthesis inhibition did not sensitize the TRAIL-resistant line to TRAIL. Because these data suggested that sensitivity of ESFTs to TRAIL was mainly based on the presence of DR4/DR5, we investigated the presence of these receptors in 32 ESFT tissue sections by immunohistochemistry. We found that 23 of 32 tumor tissues (72%) expressed both receptors, 8 of 32 (25%) expressed one receptor only, and 1 was negative for both. Our finding of wide expression of DR4/DR5 in ESFT in vivo, in combination with their high sensitivity

  5. Definition of the Cattle Killer Cell Ig–like Receptor Gene Family: Comparison with Aurochs and Human Counterparts

    PubMed Central

    Sanderson, Nicholas D.; Norman, Paul J.; Guethlein, Lisbeth A.; Ellis, Shirley A.; Williams, Christina; Breen, Matthew; Park, Steven D. E.; Magee, David A.; Babrzadeh, Farbod; Warry, Andrew; Watson, Mick; Bradley, Daniel G.; MacHugh, David E.; Parham, Peter

    2014-01-01

    Under selection pressure from pathogens, variable NK cell receptors that recognize polymorphic MHC class I evolved convergently in different species of placental mammal. Unexpectedly, diversified killer cell Ig–like receptors (KIRs) are shared by simian primates, including humans, and cattle, but not by other species. Whereas much is known of human KIR genetics and genomics, knowledge of cattle KIR is limited to nine cDNA sequences. To facilitate comparison of the cattle and human KIR gene families, we determined the genomic location, structure, and sequence of two cattle KIR haplotypes and defined KIR sequences of aurochs, the extinct wild ancestor of domestic cattle. Larger than its human counterpart, the cattle KIR locus evolved through successive duplications of a block containing ancestral KIR3DL and KIR3DX genes that existed before placental mammals. Comparison of two cattle KIR haplotypes and aurochs KIR show the KIR are polymorphic and the gene organization and content appear conserved. Of 18 genes, 8 are functional and 10 were inactivated by point mutation. Selective inactivation of KIR3DL and activating receptor genes leaves a functional cohort of one inhibitory KIR3DL, one activating KIR3DX, and six inhibitory KIR3DX. Functional KIR diversity evolved from KIR3DX in cattle and from KIR3DL in simian primates. Although independently evolved, cattle and human KIR gene families share important function-related properties, indicating that cattle KIR are NK cell receptors for cattle MHC class I. Combinations of KIR and MHC class I are the major genetic factors associated with human disease and merit investigation in cattle. PMID:25398326

  6. Definition of the cattle killer cell Ig-like receptor gene family: comparison with aurochs and human counterparts.

    PubMed

    Sanderson, Nicholas D; Norman, Paul J; Guethlein, Lisbeth A; Ellis, Shirley A; Williams, Christina; Breen, Matthew; Park, Steven D E; Magee, David A; Babrzadeh, Farbod; Warry, Andrew; Watson, Mick; Bradley, Daniel G; MacHugh, David E; Parham, Peter; Hammond, John A

    2014-12-15

    Under selection pressure from pathogens, variable NK cell receptors that recognize polymorphic MHC class I evolved convergently in different species of placental mammal. Unexpectedly, diversified killer cell Ig-like receptors (KIRs) are shared by simian primates, including humans, and cattle, but not by other species. Whereas much is known of human KIR genetics and genomics, knowledge of cattle KIR is limited to nine cDNA sequences. To facilitate comparison of the cattle and human KIR gene families, we determined the genomic location, structure, and sequence of two cattle KIR haplotypes and defined KIR sequences of aurochs, the extinct wild ancestor of domestic cattle. Larger than its human counterpart, the cattle KIR locus evolved through successive duplications of a block containing ancestral KIR3DL and KIR3DX genes that existed before placental mammals. Comparison of two cattle KIR haplotypes and aurochs KIR show the KIR are polymorphic and the gene organization and content appear conserved. Of 18 genes, 8 are functional and 10 were inactivated by point mutation. Selective inactivation of KIR3DL and activating receptor genes leaves a functional cohort of one inhibitory KIR3DL, one activating KIR3DX, and six inhibitory KIR3DX. Functional KIR diversity evolved from KIR3DX in cattle and from KIR3DL in simian primates. Although independently evolved, cattle and human KIR gene families share important function-related properties, indicating that cattle KIR are NK cell receptors for cattle MHC class I. Combinations of KIR and MHC class I are the major genetic factors associated with human disease and merit investigation in cattle.

  7. Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying.

    PubMed

    Puértolas, Jaime; Conesa, María R; Ballester, Carlos; Dodd, Ian C

    2015-04-01

    Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0-10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm(3) cm(-3) for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction. PMID:25547916

  8. Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying

    PubMed Central

    Puértolas, Jaime; Conesa, María R.; Ballester, Carlos; Dodd, Ian C.

    2015-01-01

    Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0–10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm3 cm–3 for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction. PMID:25547916

  9. Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying.

    PubMed

    Puértolas, Jaime; Conesa, María R; Ballester, Carlos; Dodd, Ian C

    2015-04-01

    Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0-10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm(3) cm(-3) for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction.

  10. The Role of TAM Family Receptors in Immune Cell Function: Implications for Cancer Therapy

    PubMed Central

    Paolino, Magdalena; Penninger, Josef M.

    2016-01-01

    The TAM receptor protein tyrosine kinases—Tyro3, Axl, and Mer—are essential regulators of immune homeostasis. Guided by their cognate ligands Growth arrest-specific gene 6 (Gas6) and Protein S (Pros1), these receptors ensure the resolution of inflammation by dampening the activation of innate cells as well as by restoring tissue function through promotion of tissue repair and clearance of apoptotic cells. Their central role as negative immune regulators is highlighted by the fact that deregulation of TAM signaling has been linked to the pathogenesis of autoimmune, inflammatory, and infectious diseases. Importantly, TAM receptors have also been associated with cancer development and progression. In a cancer setting, TAM receptors have a dual regulatory role, controlling the initiation and progression of tumor development and, at the same time, the associated anti-tumor responses of diverse immune cells. Thus, modulation of TAM receptors has emerged as a potential novel strategy for cancer treatment. In this review, we discuss our current understanding of how TAM receptors control immunity, with a particular focus on the regulation of anti-tumor responses and its implications for cancer immunotherapy. PMID:27775650

  11. The Top 10 Reasons Children With Autism Deserve ABA

    PubMed Central

    Walsh, Mary Beth

    2011-01-01

    We who advocate for applied behavior analysis (ABA) for children with autism spectrum disorders often construct our arguments based on the scientific evidence. However, the audience that most needs to hear this argument, that is, the parents of children, especially very young children, diagnosed with autism, may not be convinced by the science alone. This essay attempts to make the case for the multiple benefits of ABA intervention through the use of humor and anecdotes couched in a “Top Ten List,” and illustrating most points with stories of an engaging child with autism (my son, Ben). PMID:22532906

  12. Functions of third extracellular loop and helix 8 of Family B GPCRs complexed with RAMPs and characteristics of their receptor trafficking.

    PubMed

    Kuwasako, Kenji; Hay, Debbie L; Nagata, Sayaka; Murakami, Manabu; Kitamura, Kazuo; Kato, Johji

    2013-08-01

    At least one of three receptor activity-modifying proteins (RAMP1, RAMP2 and RAMP3) can interact with 10 G protein-coupled receptors (GPCRs; nine Family B GPCRs and a Family C GPCR). All three RAMPs interact with the calcitonin (CT) receptor (CTR), the CTR-like receptor (CLR), the vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating polypeptide (PACAP) 1 (VPAC1) and the VPAC2 receptor, which are all Family B GPCRs. Three RAMPs enable CTR to function as three heterodimeric receptors for amylin, which is a feeding suppression peptide. These RAMPs also transport the CLR to the cell surface, where they function as a CT gene-related peptide (CGRP) receptor (CLR/RAMP1 heterodimer) and two adrenomedullin (AM) receptors (CLR/RAMP2 and CLR/RAMP3 heterodimers). CGRP and AM are potent hypotensive peptides that exert powerful protective effects against multi-organ damage. We recently reported that the third extracellular loop (ECL3) of CLR governs the activation of AM, but not CGRP, signaling in the three CLR/RAMP heterodimers. Furthermore, we showed that in the presence of RAMP2, the eighth helix (helix 8) in the proximal portion of the cytoplasmic C-terminal tail of the CLR, which is thought to be present in all family B GPCRs, participates in receptor signaling. In addition, we demonstrated that overexpression of GPCR kinase (GRK) 2, GRK3 and GRK4 enhances the AM-induced internalization of the CLR/RAMP2 heterodimer. In this review, we describe these studies and consider their implications for other Family B GPCRs that can interact with RAMPs.

  13. GsSKP21, a Glycine soja S-phase kinase-associated protein, mediates the regulation of plant alkaline tolerance and ABA sensitivity.

    PubMed

    Liu, Ailin; Yu, Yang; Duan, Xiangbo; Sun, Xiaoli; Duanmu, Huizi; Zhu, Yanming

    2015-01-01

    Plant SKP1-like family proteins, components of the SCF complex E3 ligases, are involved in the regulation of plant development and stress responses. Little is known about the precise function of SKP genes in plant responses to environmental stresses. GsSKP21 was initially identified as a potential stress-responsive gene based on the transcriptome sequencing of Glycine soja. In this study, we found that GsSKP21 protein contains highly conserved SKP domains in its N terminus and an extra unidentified domain in its C terminus. The transcript abundance of GsSKP21, detected by quantitative real-time PCR, was induced under the treatment of alkali and salt stresses. Overexpression of GsSKP21 in Arabidopsis dramatically increased plant tolerance to alkali stress. Furthermore, we found that overexpression of GsSKP21 resulted in decreased ABA sensitivity during both the seed germination and early seedling growth stages. GsSKP21 mediated ABA signaling by altering the expression levels of the ABA signaling-related and ABA-induced genes. We also investigated the tissue expression specificity and subcellular localization of GsSKP21. These results suggest that GsSKP21 is important for plant tolerance to alkali stress and plays a critical regulatory role in the ABA-mediated stress response.

  14. Identification and Quantification of a New Family of Peptide Endocannabinoids (Pepcans) Showing Negative Allosteric Modulation at CB1 Receptors*

    PubMed Central

    Bauer, Mark; Chicca, Andrea; Tamborrini, Marco; Eisen, David; Lerner, Raissa; Lutz, Beat; Poetz, Oliver; Pluschke, Gerd; Gertsch, Jürg

    2012-01-01

    The α-hemoglobin-derived dodecapeptide RVD-hemopressin (RVDPVNFKLLSH) has been proposed to be an endogenous agonist for the cannabinoid receptor type 1 (CB1). To study this peptide, we have raised mAbs against its C-terminal part. Using an immunoaffinity mass spectrometry approach, a whole family of N-terminally extended peptides in addition to RVD-Hpα were identified in rodent brain extracts and human and mouse plasma. We designated these peptides Pepcan-12 (RVDPVNFKLLSH) to Pepcan-23 (SALSDLHAHKLRVDPVNFKLLSH), referring to peptide length. The most abundant Pepcans found in the brain were tested for CB1 receptor binding. In the classical radioligand displacement assay, Pepcan-12 was the most efficacious ligand but only partially displaced both [3H]CP55,940 and [3H]WIN55,212-2. The data were fitted with the allosteric ternary complex model, revealing a cooperativity factor value α < 1, thus indicating a negative allosteric modulation. Dissociation kinetic studies of [3H]CP55,940 in the absence and presence of Pepcan-12 confirmed these results by showing increased dissociation rate constants induced by Pepcan-12. A fluorescently labeled Pepcan-12 analog was synthesized to investigate the binding to CB1 receptors. Competition binding studies revealed Ki values of several Pepcans in the nanomolar range. Accordingly, using competitive ELISA, we found low nanomolar concentrations of Pepcans in human plasma and ∼100 pmol/g in mouse brain. Surprisingly, Pepcan-12 exhibited potent negative allosteric modulation of the orthosteric agonist-induced cAMP accumulation, [35S]GTPγS binding, and CB1 receptor internalization. Pepcans are the first endogenous allosteric modulators identified for CB1 receptors. Given their abundance in the brain, Pepcans could play an important physiological role in modulating endocannabinoid signaling. PMID:22952224

  15. The relaxin family peptide receptors and their ligands: new developments and paradigms in the evolution from jawless fish to mammals.

    PubMed

    Yegorov, Sergey; Bogerd, Jan; Good, Sara V

    2014-12-01

    Relaxin family peptide receptors (Rxfps) and their ligands, relaxin (Rln) and insulin-like (Insl) peptides, are broadly implicated in the regulation of reproductive and neuroendocrine processes in mammals. Most placental mammals harbour genes for four receptors, namely rxfp1, rxfp2, rxfp3 and rxfp4. The number and identity of rxfps in other vertebrates are immensely variable, which is probably attributable to intraspecific variation in reproductive and neuroendocrine regulation. Here, we highlight several interesting, but greatly overlooked, aspects of the rln/insl-rxfp evolutionary history: the ancient origin, recruitment of novel receptors, diverse roles of selection, differential retention and lineage-specific loss of genes over evolutionary time. The tremendous diversity of rln/insl and rxfp genes appears to have arisen from two divergent receptors and one ligand that were duplicated by whole genome duplications (WGD) in early vertebrate evolution, although several genes, notably relaxin in mammals, were also duplicated via small scale duplications. Duplication and loss of genes have varied across lineages: teleosts retained more WGD-derived genes, dominated by those thought to be involved in neuroendocrine regulation (rln3, insl5 and rxfp 3/4 genes), while eutherian mammals witnessed the diversification and rapid evolution of genes involved in reproduction (rln/insl3). Several genes that arose early in evolutionary history were lost in most mammals, but retained in teleosts and, to a lesser extent, in early diverging tetrapods. To elaborate on their evolutionary history, we provide updated phylogenies of the Rxfp1/2 and Rxfp3/4 receptors and their ligands, including new sequences from early diverging vertebrate taxa such as coelacanth, skate, spotted gar, and lamprey. We also summarize the recent progress made towards understanding the functional biology of Rxfps in non-mammalian taxa, providing a new conceptual framework for research on Rxfp signaling across

  16. Exome Sequencing Reveals Novel Rare Variants in the Ryanodine Receptor and Calcium Channel Genes in Malignant Hyperthermia Families

    PubMed Central

    Kim, Jerry H.; Jarvik, Gail P.; Browning, Brian L.; Rajagopalan, Ramakrishnan; Gordon, Adam S.; Rieder, Mark J.; Robertson, Peggy D.; Nickerson, Deborah A.; Fisher, Nickla A.; Hopkins, Philip M.

    2014-01-01

    Background About half of malignant hyperthermia (MH) cases are associated with skeletal muscle ryanodine receptor 1 (RYR1) and calcium channel, voltage-dependent, L type, α1S subunit (CACNA1S) gene mutations, leaving many with an unknown cause. We chose to apply a sequencing approach to uncover causal variants in unknown cases. Sequencing the exome, the protein-coding region of the genome, has power at low sample sizes and identified the cause of over a dozen Mendelian disorders. Methods We considered four families with multiple MH cases but in whom no mutations in RYR1 and CACNA1S had been identified by Sanger sequencing of complementary DNA. Exome sequencing of two affecteds per family, chosen for maximum genetic distance, were compared. Variants were ranked by allele frequency, protein change, and measures of conservation among mammals to assess likelihood of causation. Finally, putative pathogenic mutations were genotyped in other family members to verify cosegregation with MH. Results Exome sequencing revealed 1 rare RYR1 nonsynonymous variant in each of 3 families (Asp1056His, Val2627Met, Val4234Leu), and 1 CACNA1S variant (Thr1009Lys) in a 4th family. These were not seen in variant databases or in our control population sample of 5379 exomes. Follow-up sequencing in other family members verified cosegregation of alleles with MH. Conclusions Using both exome sequencing and allele frequency data from large sequencing efforts may aid genetic diagnosis of MH. In our sample, it was more sensitive for variant detection in known genes than Sanger sequencing of complementary DNA, and allows for the possibility of novel gene discovery. PMID:24013571

  17. The Ethylene Receptors ETHYLENE RESPONSE1 and ETHYLENE RESPONSE2 Have Contrasting Roles in Seed Germination of Arabidopsis during Salt Stress.

    PubMed

    Wilson, Rebecca L; Kim, Heejung; Bakshi, Arkadipta; Binder, Brad M

    2014-05-12

    In Arabidopsis (Arabidopsis thaliana), ethylene responses are mediated by a family of five receptors that have both overlapping and nonoverlapping roles. In this study, we used loss-of-function mutants for each receptor isoform to determine the role of individual isoforms in seed germination under salt stress. From this analysis, we found subfunctionalization of the receptors in the control of seed germination during salt stress. Specifically, loss of ETHYLENE RESPONSE1 (ETR1) or ETHYLENE INSENSITIVE4 (EIN4) leads to accelerated germination, loss of ETR2 delays germination, and loss of either ETHYLENE RESPONSE SENSOR1 (ERS1) or ERS2 has no measurable effect on germination. Epistasis analysis indicates that ETR1 and EIN4 function additively with ETR2 to control this trait. Interestingly, regulation of germination by ETR1 requires the full-length receptor. The differences in germination between etr1 and etr2 loss-of-function mutants under salt stress could not be explained by differences in the production of or sensitivity to ethylene, gibberellin, or cytokinin. Instead, etr1 loss-of-function mutants have reduced sensitivity to abscisic acid (ABA) and germinate earlier than the wild type, whereas etr2 loss-of-function mutants have increased sensitivity to ABA and germinate slower than the wild type. Additionally, the differences in seed germination on salt between the two mutants and the wild type are eliminated by the ABA biosynthetic inhibitor norflurazon. These data suggest that ETR1 and ETR2 have roles independent of ethylene signaling that affect ABA signaling and result in altered germination during salt stress.

  18. Discovery of sea urchin NGFFFamide receptor unites a bilaterian neuropeptide family

    PubMed Central

    Semmens, Dean C.; Beets, Isabel; Rowe, Matthew L.; Blowes, Liisa M.; Oliveri, Paola; Elphick, Maurice R.

    2015-01-01

    Neuropeptides are ancient regulators of physiology and behaviour, but reconstruction of neuropeptide evolution is often difficult owing to lack of sequence conservation. Here, we report that the receptor for the neuropeptide NGFFFamide in the sea urchin Strongylocentrotus purpuratus (phylum Echinodermata) is an orthologue of vertebrate neuropeptide-S (NPS) receptors and crustacean cardioactive peptide (CCAP) receptors. Importantly, this has facilitated reconstruction of the evolution of two bilaterian neuropeptide signalling systems. Genes encoding the precursor of a vasopressin/oxytocin-type neuropeptide and its receptor duplicated in a common ancestor of the Bilateria. One copy of the precursor retained ancestral features, as seen in highly conserved vasopressin/oxytocin–neurophysin-type precursors. The other copy diverged, but this took different courses in protostomes and deuterostomes. In protostomes, the occurrence of a disulfide bridge in neuropeptide product(s) of the precursor was retained, as in CCAP, but with loss of the neurophysin domain. In deuterostomes, we see the opposite scenario—the neuropeptides lost the disulfide bridge, and neurophysin was retained (as in the NGFFFamide precursor) but was subsequently lost in vertebrate NPS precursors. Thus, the sea urchin NGFFFamide precursor and receptor are ‘missing links’ in the evolutionary history of neuropeptides that control ecdysis in arthropods (CCAP) and regulate anxiety in humans (NPS). PMID:25904544

  19. Nuclear receptor 4A (NR4A) family - orphans no more.

    PubMed

    Safe, Stephen; Jin, Un-Ho; Morpurgo, Benjamin; Abudayyeh, Ala; Singh, Mandip; Tjalkens, Ronald B

    2016-03-01

    The orphan nuclear receptors NR4A1, NR4A2 and NR4A3 are immediate early genes induced by multiple stressors, and the NR4A receptors play an important role in maintaining cellular homeostasis and disease. There is increasing evidence for the role of these receptors in metabolic, cardiovascular and neurological functions and also in inflammation and inflammatory diseases and in immune functions and cancer. Despite the similarities of NR4A1, NR4A2 and NR4A3 and their interactions with common cis-genomic elements, they exhibit unique activities and cell-/tissue-specific functions. Although endogenous ligands for NR4A receptors have not been identified, there is increasing evidence that structurally-diverse synthetic molecules can directly interact with the ligand binding domain of NR4A1 and act as agonists or antagonists, and ligands for NR4A2 and NR4A3 have also been identified. Since NR4A receptors are key factors in multiple diseases, there are opportunities for the future development of NR4A ligands for clinical applications in treating multiple health problems including metabolic, neurologic and cardiovascular diseases, other inflammatory conditions, and cancer.

  20. ABA-deficiency results in reduced plant and fruit size in tomato.

    PubMed

    Nitsch, L; Kohlen, W; Oplaat, C; Charnikhova, T; Cristescu, S; Michieli, P; Wolters-Arts, M; Bouwmeester, H; Mariani, C; Vriezen, W H; Rieu, I

    2012-06-15

    Abscisic acid (ABA) deficient mutants, such as notabilis and flacca, have helped elucidating the role of ABA during plant development and stress responses in tomato (Solanum lycopersicum L.). However, these mutants have only moderately decreased ABA levels. Here we report on plant and fruit development in the more strongly ABA-deficient notabilis/flacca (not/flc) double mutant. We observed that plant growth, leaf-surface area, drought-induced wilting and ABA-related gene expression in the different genotypes were strongly correlated with the ABA levels and thus most strongly affected in the not/flc double mutants. These mutants also had reduced fruit size that was caused by an overall smaller cell size. Lower ABA levels in fruits did not correlate with changes in auxin levels, but were accompanied by higher ethylene evolution rates. This suggests that in a wild-type background ABA stimulates cell enlargement during tomato fruit growth via a negative effect on ethylene synthesis.

  1. Designed abscisic acid analogs as antagonists of PYL-PP2C receptor interactions.

    PubMed

    Takeuchi, Jun; Okamoto, Masanori; Akiyama, Tomonori; Muto, Takuya; Yajima, Shunsuke; Sue, Masayuki; Seo, Mitsunori; Kanno, Yuri; Kamo, Tsunashi; Endo, Akira; Nambara, Eiji; Hirai, Nobuhiro; Ohnishi, Toshiyuki; Cutler, Sean R; Todoroki, Yasushi

    2014-06-01

    The plant stress hormone abscisic acid (ABA) is critical for several abiotic stress responses. ABA signaling is normally repressed by group-A protein phosphatases 2C (PP2Cs), but stress-induced ABA binds Arabidopsis PYR/PYL/RCAR (PYL) receptors, which then bind and inhibit PP2Cs. X-ray structures of several receptor-ABA complexes revealed a tunnel above ABA's 3' ring CH that opens at the PP2C binding interface. Here, ABA analogs with sufficiently long 3' alkyl chains were predicted to traverse this tunnel and block PYL-PP2C interactions. To test this, a series of 3'-alkylsulfanyl ABAs were synthesized with different alkyl chain lengths. Physiological, biochemical and structural analyses revealed that a six-carbon alkyl substitution produced a potent ABA antagonist that was sufficiently active to block multiple stress-induced ABA responses in vivo. This study provides a new approach for the design of ABA analogs, and the results validated structure-based design for this target class. PMID:24792952

  2. Designed abscisic acid analogs as antagonists of PYL-PP2C receptor interactions.

    PubMed

    Takeuchi, Jun; Okamoto, Masanori; Akiyama, Tomonori; Muto, Takuya; Yajima, Shunsuke; Sue, Masayuki; Seo, Mitsunori; Kanno, Yuri; Kamo, Tsunashi; Endo, Akira; Nambara, Eiji; Hirai, Nobuhiro; Ohnishi, Toshiyuki; Cutler, Sean R; Todoroki, Yasushi

    2014-06-01

    The plant stress hormone abscisic acid (ABA) is critical for several abiotic stress responses. ABA signaling is normally repressed by group-A protein phosphatases 2C (PP2Cs), but stress-induced ABA binds Arabidopsis PYR/PYL/RCAR (PYL) receptors, which then bind and inhibit PP2Cs. X-ray structures of several receptor-ABA complexes revealed a tunnel above ABA's 3' ring CH that opens at the PP2C binding interface. Here, ABA analogs with sufficiently long 3' alkyl chains were predicted to traverse this tunnel and block PYL-PP2C interactions. To test this, a series of 3'-alkylsulfanyl ABAs were synthesized with different alkyl chain lengths. Physiological, biochemical and structural analyses revealed that a six-carbon alkyl substitution produced a potent ABA antagonist that was sufficiently active to block multiple stress-induced ABA responses in vivo. This study provides a new approach for the design of ABA analogs, and the results validated structure-based design for this target class.

  3. Cell-free conversion of 1 prime -deoxy- sup 2 H-ABA to sup 2 H-ABA in extracts from Cercospora rosicola

    SciTech Connect

    Al-Nimri, L.; Coolbaugh, R.C. )

    1990-05-01

    The characteristics of the enzyme converting 1{prime}-deoxy-ABA into ABA have been studied in the fungus C. rosicola. Enzyme extracts were prepared from cold-pressed mycelia of C. rosicola. The suspension was a high speed supernatant and a microsomal fraction. A cell-free system was developed to convert 1{prime}-deoxy-{sup 2}H-ABA into {sup 2}H-ABA using a reaction mixture containing 300 {mu}l enzyme extract, 10 {mu}m 1{prime}-deoxy-{sup 2}H-ABA. The reaction products were chromatographed by reverse phase HPLC. The presumptive ABA fractions were collected and {sup 2}H-ABA was quantified by GC-MS using a {sup 2}H-(2Z, 4E)-ABA standard curve. 1{prime}-deoxy-{sup 2}H-ABA was converted to an average of 1.47 pmole {sup 2}H-ABA/mg protein per min. Most of the enzymic activity was found in the microsomal fraction. The reaction required NADPH and was enhanced by FAD. The reaction was not inhibited by triarimol.

  4. Primary structure of rat cardiac beta-adrenergic and muscarinic cholinergic receptors obtained by automated DNA sequence analysis: further evidence for a multigene family.

    PubMed Central

    Gocayne, J; Robinson, D A; FitzGerald, M G; Chung, F Z; Kerlavage, A R; Lentes, K U; Lai, J; Wang, C D; Fraser, C M; Venter, J C

    1987-01-01

    Two cDNA clones, lambda RHM-MF and lambda RHB-DAR, encoding the muscarinic cholinergic receptor and the beta-adrenergic receptor, respectively, have been isolated from a rat heart cDNA library. The cDNA clones were characterized by restriction mapping and automated DNA sequence analysis utilizing fluorescent dye primers. The rat heart muscarinic receptor consists of 466 amino acids and has a calculated molecular weight of 51,543. The rat heart beta-adrenergic receptor consists of 418 amino acids and has a calculated molecular weight of 46,890. The two cardiac receptors have substantial amino acid homology (27.2% identity, 50.6% with favored substitutions). The rat cardiac beta receptor has 88.0% homology (92.5% with favored substitutions) with the human brain beta receptor and the rat cardiac muscarinic receptor has 94.6% homology (97.6% with favored substitutions) with the porcine cardiac muscarinic receptor. The muscarinic cholinergic and beta-adrenergic receptors appear to be as conserved as hemoglobin and cytochrome c but less conserved than histones and are clearly members of a multigene family. These data support our hypothesis, based upon biochemical and immunological evidence, that suggests considerable structural homology and evolutionary conservation between adrenergic and muscarinic cholinergic receptors. To our knowledge, this is the first report utilizing automated DNA sequence analysis to determine the structure of a gene. Images PMID:2825184

  5. Cloning and characterization of additional members of the G protein-coupled receptor family.

    PubMed

    Lee, D K; Lynch, K R; Nguyen, T; Im, D S; Cheng, R; Saldivia, V R; Liu, Y; Liu, I S; Heng, H H; Seeman, P; George, S R; O'Dowd, B F; Marchese, A

    2000-02-29

    A search of the expressed sequence tag (EST) database retrieved a human cDNA sequence which partially encoded a novel G protein-coupled receptor (GPCR) GPR26. A human genomic DNA fragment encoding a partial open reading frame (ORF) and a rat cDNA encoding the full length ORF of GPR26 were obtained by library screening. The rat GPR26 cDNA encoded a protein of 317 amino acids, most similar (albeit distantly related) to the serotonin 5-HT(5A) and gastrin releasing hormone BB2 receptors. GPR26 mRNA expression analysis revealed signals in the striatum, pons, cerebellum and cortex. HEK293 and Rh7777 cells transfected with GPR26 cDNA displayed high basal cAMP levels, slow growth rate of clonal populations and derangements of normal cell shape. We also used a sequence reported only in the patent literature encoding GPR57 (a.k.a. HNHCI32) to PCR amplify a DNA fragment which was used to screen a human genomic library. This resulted in the cloning of a genomic fragment containing a pseudogene, psiGPR57, with a 99.6% nucleotide identity to GPR57. Based on shared sequence identities, the receptor encoded by GPR57 was predicted to belong to a novel subfamily of GPCRs together with GPR58 (a.k.a. phBL5, reported only in the patent literature), putative neurotransmitter receptor (PNR) and a 5-HT(4) pseudogene. Analysis of this subfamily revealed greatest identities (approximately 56%) between the receptors encoded by GPR57 and GPR58, each with shared identities of approximately 40% with PNR. Furthermore, psiGPR57, GPR58, PNR and the 5-HT(4) pseudogene were mapped in a cluster localized to chromosome 6q22-24. PNR and GPR58 were expressed in COS cells, however no specific binding was observed for various serotonin receptor-specific ligands.

  6. Microbial receptor assay for rapid detection and identification of seven families of antimicrobial drugs in milk: collaborative study.

    PubMed

    Charm, S E; Chi, R

    1988-01-01

    A microbial competitive receptor assay for detecting residues of antibiotic families in milk was studied collaboratively by 13 laboratories. The drugs and levels (ppb) tested in this study include penicillin G, 4.8; cephapirin, 5.0; cloxacillin, 100; tetracycline, 2000; chlortetracycline, 2000; oxytetracycline, 2000; erythromycin, 200; lincomycin, 400; clindamycin, 400; sulfamethazine, 75; sulfamethoxazole, 50; sulfisoxazole, 50; streptomycin, 1000; novobiocin, 50; and chloramphenicol, 800. In this method, microbial cells added to a milk sample provide specific binding sites for which 14C or 3H labeled drug competes with drug residues in the sample. The 14C or 3H binding to the specific binding sites is measured in a scintillation counter and compared with a zero standard milk. If the sample is statistically different from the zero standard, it is positive. The assay takes about 15 min. The binding reaction occurs between the receptor site and the drug functional group, so all members of a drug family are detected. In this case, beta-lactams, tetracyclines, macrolides, aminoglycosides, novobiocin, chloramphenicol, and sulfonamides, including p-aminobenzoic acid (PABA) and its other analogs, are detectable. The incidence of false negative determinations among samples is about 1%; the incidence of false positives is about 3%. For negative cases, the relative standard deviations for repeatability ranged from 0 to 5% and for reproducibility from 0 to 6%. For positive cases, relative standard deviations ranged from 0 to 13% for repeatability and from 0 to 14% for reproducibility. The method has been adopted official first action. PMID:3260233

  7. International Union of Basic and Clinical Pharmacology. XCV. Recent Advances in the Understanding of the Pharmacology and Biological Roles of Relaxin Family Peptide Receptors 1–4, the Receptors for Relaxin Family Peptides

    PubMed Central

    Halls, Michelle L.; Bathgate, Ross A. D.; Sutton, Steve W.; Dschietzig, Thomas B.

    2015-01-01

    Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1–4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gαs, Gαi, and Gαo proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gαs- and Gαo-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gαi/Gαo proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1–4, the challenges facing the field, and current prospects for new therapeutics. PMID:25761609

  8. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides.

    PubMed

    Halls, Michelle L; Bathgate, Ross A D; Sutton, Steve W; Dschietzig, Thomas B; Summers, Roger J

    2015-01-01

    Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics.

  9. Dissociations among ABA, ABC, and AAB Recovery Effects

    ERIC Educational Resources Information Center

    Ungor, Metin; Lachnit, Harald

    2008-01-01

    In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y-) was trained in Context A. During Phase 2, participants received discrimination reversal training (X-, Y+) either in Context A (Group AAB) or in…

  10. Personality Traits Associated with Occupational "Burnout" in ABA Therapists

    ERIC Educational Resources Information Center

    Hurt, Amy A.; Grist, Cathy Lann; Malesky, Lann A., Jr.; McCord, David M.

    2013-01-01

    Background: Applied behaviour analysis (ABA) therapists typically work one-to-one with children with autism for extended periods of time, which often leads to high levels of job-related stress, lower levels of job satisfaction, increased frequency of occupational "burnout" and higher than average job turnover (Journal of Autism…

  11. ABA, AAB and ABC Renewal in Taste Aversion Learning

    ERIC Educational Resources Information Center

    Bernal-Gamboa, Rodolfo; Juarez, Yectivani; Gonzalez-Martin, Gabriela; Carranza, Rodrigo; Sanchez-Carrasco, Livia; Nieto, Javier

    2012-01-01

    Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal,…

  12. ABA and Diverse Cultural and Linguistic Environments: A Welsh Perspective

    ERIC Educational Resources Information Center

    Jones, E. W.; Hoerger, M.; Hughes, J. C.; Williams, B. M.; Jones, B.; Moseley, Y.; Hughes, D. R.; Prys, D.

    2011-01-01

    Gwynedd Local Education Authority (LEA) in North West Wales, UK, is funding a small-scale autism-specific specialist education service using ABA methodology. The program is available through the medium of Welsh, English or bilingually, depending on the individual needs of the child (Jones and Hoerger in Eur J Behav Anal 10:249-253, "2009").…

  13. Adaptive Behaviour Assessment System: Indigenous Australian Adaptation Model (ABAS: IAAM)

    ERIC Educational Resources Information Center

    du Plessis, Santie

    2015-01-01

    The study objectives were to develop, trial and evaluate a cross-cultural adaptation of the Adaptive Behavior Assessment System-Second Edition Teacher Form (ABAS-II TF) ages 5-21 for use with Indigenous Australian students ages 5-14. This study introduced a multiphase mixed-method design with semi-structured and informal interviews, school…

  14. A New Family of Receptor Tyrosine Kinases with a Venus Flytrap Binding Domain in Insects and Other Invertebrates Activated by Aminoacids

    PubMed Central

    Ahier, Arnaud; Rondard, Philippe; Gouignard, Nadège; Khayath, Naji; Huang, Siluo; Trolet, Jacques; Donoghue, Daniel J.; Gauthier, Monique; Pin, Jean-Philippe; Dissous, Colette

    2009-01-01

    Background Tyrosine kinase receptors (RTKs) comprise a large family of membrane receptors that regulate various cellular processes in cell biology of diverse organisms. We previously described an atypical RTK in the platyhelminth parasite Schistosoma mansoni, composed of an extracellular Venus flytrap module (VFT) linked through a single transmembrane domain to an intracellular tyrosine kinase domain similar to that of the insulin receptor. Methods and Findings Here we show that this receptor is a member of a new family of RTKs found in invertebrates, and particularly in insects. Sixteen new members of this family, named Venus Kinase Receptor (VKR), were identified in many insects. Structural and phylogenetic studies performed on VFT and TK domains showed that VKR sequences formed monophyletic groups, the VFT group being close to that of GABAB receptors and the TK one being close to that of insulin receptors. We show that a recombinant VKR is able to autophosphorylate on tyrosine residues, and report that it can be activated by L-arginine. This is in agreement with the high degree of conservation of the alpha amino acid binding residues found in many amino acid binding VFTs. The presence of high levels of vkr transcripts in larval forms and in female gonads indicates a putative function of VKR in reproduction and/or development. Conclusion The identification of RTKs specific for parasites and insect vectors raises new perspectives for the control of human parasitic and infectious diseases. PMID:19461966

  15. Coping as a Predictor of Burnout and General Health in Therapists Working in ABA Schools

    ERIC Educational Resources Information Center

    Griffith, G. M.; Barbakou, A.; Hastings, R. P.

    2014-01-01

    Background: Little is known about the work-related well-being of applied behaviour analysis (ABA) therapists who work in school-based contexts and deliver ABA interventions to children with autism. Methods: A questionnaire on work-related stress (burnout), general distress, perceived supervisor support and coping was completed by 45 ABA therapists…

  16. Joint association of nicotinic acetylcholine receptor variants with abdominal obesity in American Indians: the Strong Heart Family Study.

    PubMed

    Zhu, Yun; Yang, Jingyun; Yeh, Fawn; Cole, Shelley A; Haack, Karin; Lee, Elisa T; Howard, Barbara V; Zhao, Jinying

    2014-01-01

    Cigarette smoke is a strong risk factor for obesity and cardiovascular disease. The effect of genetic variants involved in nicotine metabolism on obesity or body composition has not been well studied. Though many genetic variants have previously been associated with adiposity or body fat distribution, a single variant usually confers a minimal individual risk. The goal of this study is to evaluate the joint association of multiple variants involved in cigarette smoke or nicotine dependence with obesity-related phenotypes in American Indians. To achieve this goal, we genotyped 61 tagSNPs in seven genes encoding nicotine acetylcholine receptors (nAChRs) in 3,665 American Indians participating in the Strong Heart Family Study. Single SNP association with obesity-related traits was tested using family-based association, adjusting for traditional risk factors including smoking. Joint association of all SNPs in the seven nAChRs genes were examined by gene-family analysis based on weighted truncated product method (TPM). Multiple testing was controlled by false discovery rate (FDR). Results demonstrate that multiple SNPs showed weak individual association with one or more measures of obesity, but none survived correction for multiple testing. However, gene-family analysis revealed significant associations with waist circumference (p = 0.0001) and waist-to-hip ratio (p = 0.0001), but not body mass index (p = 0.20) and percent body fat (p = 0.29), indicating that genetic variants are jointly associated with abdominal, but not general, obesity among American Indians. The observed combined genetic effect is independent of cigarette smoking per se. In conclusion, multiple variants in the nAChR gene family are jointly associated with abdominal obesity in American Indians, independent of general obesity and cigarette smoking per se.

  17. Dopamine D2/3 receptor antagonism reduces activity-based anorexia

    PubMed Central

    Klenotich, S J; Ho, E V; McMurray, M S; Server, C H; Dulawa, S C

    2015-01-01

    Anorexia nervosa (AN) is an eating disorder characterized by severe hypophagia and weight loss, and an intense fear of weight gain. Activity-based anorexia (ABA) refers to the weight loss, hypophagia and paradoxical hyperactivity that develops in rodents exposed to running wheels and restricted food access, and provides a model for aspects of AN. The atypical antipsychotic olanzapine was recently shown to reduce both AN symptoms and ABA. We examined which component of the complex pharmacological profile of olanzapine reduces ABA. Mice received 5-HT2A/2C, 5-HT3, dopamine D1-like, D2, D3 or D2/3 antagonist treatment, and were assessed for food intake, body weight, wheel running and survival in ABA. D2/3 receptor antagonists eticlopride and amisulpride reduced weight loss and hypophagia, and increased survival during ABA. Furthermore, amisulpride produced larger reductions in weight loss and hypophagia than olanzapine. Treatment with either D3 receptor antagonist SB277011A or D2 receptor antagonist L-741,626 also increased survival. All the other treatments either had no effect or worsened ABA. Overall, selective antagonism of D2 and/or D3 receptors robustly reduces ABA. Studies investigating the mechanisms by which D2 and/or D3 receptors regulate ABA, and the efficacy for D2/3 and/or D3 antagonists to treat AN, are warranted. PMID:26241351

  18. Dopamine D2/3 receptor antagonism reduces activity-based anorexia.

    PubMed

    Klenotich, S J; Ho, E V; McMurray, M S; Server, C H; Dulawa, S C

    2015-08-04

    Anorexia nervosa (AN) is an eating disorder characterized by severe hypophagia and weight loss, and an intense fear of weight gain. Activity-based anorexia (ABA) refers to the weight loss, hypophagia and paradoxical hyperactivity that develops in rodents exposed to running wheels and restricted food access, and provides a model for aspects of AN. The atypical antipsychotic olanzapine was recently shown to reduce both AN symptoms and ABA. We examined which component of the complex pharmacological profile of olanzapine reduces ABA. Mice received 5-HT(2A/2C), 5-HT3, dopamine D1-like, D2, D3 or D2/3 antagonist treatment, and were assessed for food intake, body weight, wheel running and survival in ABA. D2/3 receptor antagonists eticlopride and amisulpride reduced weight loss and hypophagia, and increased survival during ABA. Furthermore, amisulpride produced larger reductions in weight loss and hypophagia than olanzapine. Treatment with either D3 receptor antagonist SB277011A or D2 receptor antagonist L-741,626 also increased survival. All the other treatments either had no effect or worsened ABA. Overall, selective antagonism of D2 and/or D3 receptors robustly reduces ABA. Studies investigating the mechanisms by which D2 and/or D3 receptors regulate ABA, and the efficacy for D2/3 and/or D3 antagonists to treat AN, are warranted.

  19. Diverse Transcriptional Programs Associated with Environmental Stress and Hormones in the Arabidopsis Receptor-Like Kinase Gene Family

    PubMed Central

    Chae, Lee; Sudat, Sylvia; Dudoit, Sandrine; Zhu, Tong; Luan, Sheng

    2009-01-01

    The genome of Arabidopsis thaliana encodes more than 600 receptor-like kinase (RLK) genes, by far the dominant class of receptors found in land plants. Although similar to the mammalian receptor tyrosine kinases, plant RLKs are serine/threonine kinases that represent a novel signaling innovation unique to plants and, consequently, an excellent opportunity to understand how extracellular signaling evolved and functions in plants as opposed to animals. RLKs are predicted to be major components of the signaling pathways that allow plants to respond to environmental and developmental conditions. However, breakthroughs in identifying these processes have been limited to only a handful of individual RLKs. Here, we used a Syngenta custom Arabidopsis GeneChip array to compile a detailed profile of the transcriptional activity of 604 receptor-like kinase genes after exposure to a cross-section of known signaling factors in plants, including abiotic stresses, biotic stresses, and hormones. In the 68 experiments comprising the study, we found that 582 of the 604 RLK genes displayed a two-fold or greater change in expression to at least one of 12 types of treatments, thereby providing a large body of experimental evidence for targeted functional screens of individual RLK genes. We investigated whether particular subfamilies of RLK genes are responsive to specific types of signals and found that each subfamily displayed broad ranges of expression, as opposed to being targeted towards particular signal classes. Finally, by analyzing the divergence of sequence and gene expression among the RLK subfamilies, we present evidence as to the functional basis for the expansion of the RLKs and how this expansion may have affected conservation and divergences in their function. Taken as a whole, our study represents a preliminary, working model of processes and interactions in which the members of the RLK gene family may be involved, where such information has remained elusive for so many

  20. Identification of dopamine receptors across the extant avian family tree and analysis with other clades uncovers a polyploid expansion among vertebrates

    PubMed Central

    Haug-Baltzell, Asher; Jarvis, Erich D.; McCarthy, Fiona M.; Lyons, Eric

    2015-01-01

    Dopamine is an important central nervous system transmitter that functions through two classes of receptors (D1 and D2) to influence a diverse range of biological processes in vertebrates. With roles in regulating neural activity, behavior, and gene expression, there has been great interest in understanding the function and evolution dopamine and its receptors. In this study, we use a combination of sequence analyses, microsynteny analyses, and phylogenetic relationships to identify and characterize both the D1 (DRD1A, DRD1B, DRD1C, and DRD1E) and D2 (DRD2, DRD3, and DRD4) dopamine receptor gene families in 43 recently sequenced bird genomes representing the major ordinal lineages across the avian family tree. We show that the common ancestor of all birds possessed at least seven D1 and D2 receptors, followed by subsequent independent losses in some lineages of modern birds. Through comparisons with other vertebrate and invertebrate species we show that two of the D1 receptors, DRD1A and DRD1B, and two of the D2 receptors, DRD2 and DRD3, originated from a whole genome duplication event early in the vertebrate lineage, providing the first conclusive evidence of the origin of these highly conserved receptors. Our findings provide insight into the evolutionary development of an important modulatory component of the central nervous system in vertebrates, and will help further unravel the complex evolutionary and functional relationships among dopamine receptors. PMID:26500483

  1. Receptor communication within the lymphocyte plasma membrane: a role for the thrombospondin family of matricellular proteins.

    PubMed

    Forslöw, A; Liu, Z; Sundqvist, K-G

    2007-01-01

    Lymphocytes, the principal cells of the immune system, carry out immune surveillance throughout the body by their unique capacity to constantly reposition themselves between a free-floating vascular state and a tissue state characterized by migration and frequent adhesive interactions with endothelial cells and components of the extracellular matrix. Therefore, mechanisms co-ordinating adhesion and migration with signals delivered through antigen recognition probably play a pivotal role for the regulation of lymphocyte behaviour and function. Endogenous thrombospondin-1 (TSP-1) seems to be the hub in such a mechanism for autocrine regulation of T cell adhesion and migration. TSP-1 functions as a mediator of cis interaction of vital receptors within the T lymphocyte plasma membrane, including integrins, low density lipoprotein receptor-related protein, calreticulin and integrin-associated protein.

  2. Feeding and the rhodopsin family g-protein coupled receptors in nematodes and arthropods.

    PubMed

    Cardoso, João C R; Félix, Rute C; Fonseca, Vera G; Power, Deborah M

    2012-01-01

    In vertebrates, receptors of the rhodopsin G-protein coupled superfamily (GPCRs) play an important role in the regulation of feeding and energy homeostasis and are activated by peptide hormones produced in the brain-gut axis. These peptides regulate appetite and energy expenditure by promoting or inhibiting food intake. Sequence and function homologs of human GPCRs involved in feeding exist in the nematode roundworm, Caenorhabditis elegans (C. elegans), and the arthropod fruit fly, Drosophila melanogaster (D. melanogaster), suggesting that the mechanisms that regulate food intake emerged early and have been conserved during metazoan radiation. Nematodes and arthropods are the most diverse and successful animal phyla on Earth. They can survive in a vast diversity of environments and have acquired distinct life styles and feeding strategies. The aim of the present review is to investigate if this diversity has affected the evolution of invertebrate GPCRs. Homologs of the C. elegans and D. melanogaster rhodopsin receptors were characterized in the genome of other nematodes and arthropods and receptor evolution compared. With the exception of bombesin receptors (BBR) that are absent from nematodes, a similar gene complement was found. In arthropods, rhodopsin GPCR evolution is characterized by species-specific gene duplications and deletions and in nematodes by gene expansions in species with a free-living stage and gene deletions in representatives of obligate parasitic taxa. Based upon variation in GPCR gene number and potentially divergent functions within phyla we hypothesize that life style and feeding diversity practiced by nematodes and arthropods was one factor that contributed to rhodopsin GPCR gene evolution. Understanding how the regulation of food intake has evolved in invertebrates will contribute to the development of novel drugs to control nematodes and arthropods and the pests and diseases that use them as vectors. PMID:23264768

  3. ApoC-III inhibits clearance of triglyceride-rich lipoproteins through LDL family receptors.

    PubMed

    Gordts, Philip L S M; Nock, Ryan; Son, Ni-Huiping; Ramms, Bastian; Lew, Irene; Gonzales, Jon C; Thacker, Bryan E; Basu, Debapriya; Lee, Richard G; Mullick, Adam E; Graham, Mark J; Goldberg, Ira J; Crooke, Rosanne M; Witztum, Joseph L; Esko, Jeffrey D

    2016-08-01

    Hypertriglyceridemia is an independent risk factor for cardiovascular disease, and plasma triglycerides (TGs) correlate strongly with plasma apolipoprotein C-III (ApoC-III) levels. Antisense oligonucleotides (ASOs) for ApoC-III reduce plasma TGs in primates and mice, but the underlying mechanism of action remains controversial. We determined that a murine-specific ApoC-III-targeting ASO reduces fasting TG levels through a mechanism that is dependent on low-density lipoprotein receptors (LDLRs) and LDLR-related protein 1 (LRP1). ApoC-III ASO treatment lowered plasma TGs in mice lacking lipoprotein lipase (LPL), hepatic heparan sulfate proteoglycan (HSPG) receptors, LDLR, or LRP1 and in animals with combined deletion of the genes encoding HSPG receptors and LDLRs or LRP1. However, the ApoC-III ASO did not lower TG levels in mice lacking both LDLR and LRP1. LDLR and LRP1 were also required for ApoC-III ASO-induced reduction of plasma TGs in mice fed a high-fat diet, in postprandial clearance studies, and when ApoC-III-rich or ApoC-III-depleted lipoproteins were injected into mice. ASO reduction of ApoC-III had no effect on VLDL secretion, heparin-induced TG reduction, or uptake of lipids into heart and skeletal muscle. Our data indicate that ApoC-III inhibits turnover of TG-rich lipoproteins primarily through a hepatic clearance mechanism mediated by the LDLR/LRP1 axis. PMID:27400128

  4. ApoC-III inhibits clearance of triglyceride-rich lipoproteins through LDL family receptors

    PubMed Central

    Gordts, Philip L.S.M.; Son, Ni-Huiping; Ramms, Bastian; Lew, Irene; Gonzales, Jon C.; Thacker, Bryan E.; Basu, Debapriya; Lee, Richard G.; Mullick, Adam E.; Graham, Mark J.; Goldberg, Ira J.; Crooke, Rosanne M.; Witztum, Joseph L.

    2016-01-01

    Hypertriglyceridemia is an independent risk factor for cardiovascular disease, and plasma triglycerides (TGs) correlate strongly with plasma apolipoprotein C-III (ApoC-III) levels. Antisense oligonucleotides (ASOs) for ApoC-III reduce plasma TGs in primates and mice, but the underlying mechanism of action remains controversial. We determined that a murine-specific ApoC-III–targeting ASO reduces fasting TG levels through a mechanism that is dependent on low-density lipoprotein receptors (LDLRs) and LDLR-related protein 1 (LRP1). ApoC-III ASO treatment lowered plasma TGs in mice lacking lipoprotein lipase (LPL), hepatic heparan sulfate proteoglycan (HSPG) receptors, LDLR, or LRP1 and in animals with combined deletion of the genes encoding HSPG receptors and LDLRs or LRP1. However, the ApoC-III ASO did not lower TG levels in mice lacking both LDLR and LRP1. LDLR and LRP1 were also required for ApoC-III ASO–induced reduction of plasma TGs in mice fed a high-fat diet, in postprandial clearance studies, and when ApoC-III–rich or ApoC-III–depleted lipoproteins were injected into mice. ASO reduction of ApoC-III had no effect on VLDL secretion, heparin-induced TG reduction, or uptake of lipids into heart and skeletal muscle. Our data indicate that ApoC-III inhibits turnover of TG-rich lipoproteins primarily through a hepatic clearance mechanism mediated by the LDLR/LRP1 axis. PMID:27400128

  5. Multiple functions and essential roles of nuclear receptor coactivators of bHLH-PAS family.

    PubMed

    Pecenova, L; Farkas, Robert

    2016-07-01

    Classical non-peptide hormones, such as steroids, retinoids, thyroid hormones, vitamin D3 and their derivatives including prostaglandins, benzoates, oxysterols, and bile acids, are collectively designated as small lipophilic ligands, acting via binding to the nuclear receptors (NRs). The NRs form a large superfamily of transcription factors that participate virtually in every key biological process. They control various aspects of animal development, fertility, gametogenesis, and numerous metabolic pathways, and can be misregulated in many types of cancers. Their enormous functional plasticity, as transcription factors, relates in part to NR-mediated interactions with plethora of coregulatory proteins upon ligand binding to their ligand binding domains (LBD), or following covalent modification. Here, we review some general views of a specific group of NR coregulators, so-called nuclear receptor coactivators (NRCs) or steroid receptor coactivators (SRCs) and highlight some of their unique functions/roles, which are less extensively mentioned and discussed in other reviews. We also try to pinpoint few neglected moments in the cooperative action of SRCs, which may also indicate their variable roles in the hormone-independent signaling pathways. PMID:27560800

  6. A member of the TGF-beta receptor gene family in the parasitic nematode Brugia pahangi.

    PubMed

    Gomez-Escobar, N; van den Biggelaar, A; Maizels, R

    1997-10-15

    The full length cDNA sequence of a Type I transforming growth factor-beta (TGF-beta) receptor has been isolated from the filarial parasitic nematode Brugia pahangi. This new gene, designated Bp-trk-1, encodes a predicted 645 amino acid sequence with an N-terminal hydrophobic stretch which may act as a signal peptide. The extracellular portion (residues 15-187) is cysteine-rich and has three potential N-glycosylation sites. At positions 250-255 the protein contains the glycine-serine rich motif characteristic of Type I receptors. The closest homologue is a Caenorhabditis elegans gene (Q09488) in cosmid C32D5.2 which shares 67% amino acid identity with Bp-trk-1 in the most conserved kinase domain (aa 259-482). Other type I receptors such as C. elegans daf-1 and Drosophila tkv show 38-53% identity in the same region. Some residues conserved in Drosophila and vertebrates are not present in the B. pahangi sequence. RT-PCR amplification has been used to show that the transcript is expressed in the three main stages of the B. pahangi life cycle: microfilariae, infective larvae and adults. The ligand remains unknown at this time but is likely to be most similar to that for C. elegans Q09488. PMID:9358045

  7. Family environment and adult resilience: contributions of positive parenting and the oxytocin receptor gene

    PubMed Central

    Bradley, Bekh; Davis, Telsie A.; Wingo, Aliza P.; Mercer, Kristina B.; Ressler, Kerry J.

    2013-01-01

    Background Abundant research shows that childhood adversity increases the risk for adult psychopathology while research on influences of positive family environment on risk for psychopathology is limited. Similarly, a growing body of research examines genetic and gene by environment predictors of psychopathology, yet such research on predictors of resilience is sparse. Objectives We examined the role of positive factors in childhood family environment (CFE) and the OXTR rs53576 genotype in predicting levels of adult resilient coping and positive affect. We also examined whether the relationship between positive factors in the CFEs and adult resilient coping and positive affect varied across OXTR rs53576 genotype. Methods We gathered self-report data on childhood environment, trauma history, and adult resilience and positive affect in a sample of 971 African American adults. Results We found that positive CFE was positively associated with higher levels of resilient coping and positive affect in adulthood after controlling for childhood maltreatment, other trauma, and symptoms of posttraumatic stress disorder. We did not find a direct effect of OXTR 53576 on a combined resilient coping/positive-affect-dependent variable, but we did find an interaction of OXTR rs53576 with family environment. Conclusions Our data suggest that even in the face of adversity, positive aspects of the family environment may contribute to resilience. These results highlight the importance of considering protective developmental experiences and the interaction of such experiences with genetic variants in risk and resilience research. PMID:24058725

  8. Green fluorescent protein fused to peptide agonists of two dissimilar G protein-coupled receptors: novel ligands of the bradykinin B2 (rhodopsin family) receptor and parathyroid hormone PTH1 (secretin family) receptor.

    PubMed

    Charest-Morin, Xavier; Fortin, Jean-Philippe; Bawolak, Marie-Thérèse; Lodge, Robert; Marceau, François

    2013-10-01

    We hypothesized that peptide hormone sequences that stimulate and internalize G protein-coupled receptors (GPCRs) could be prolonged with a functional protein cargo. To verify this, we have selected two widely different pairs of peptide hormones and GPCRs that nevertheless share agonist-induced arrestin-mediated internalization. For the parathyroid hormone (PTH) PTH1 receptor (PTH1R) and the bradykinin (BK) B2 receptor (B2R), we have designed fusion proteins of the agonists PTH1-34 and maximakinin (MK, a BK homologue) with the enhanced green fluorescent protein (EGFP), thus producing candidate high molecular weight ligands. According to docking models of each hormone to its receptor, EGFP was fused either at the N-terminus (MK) or C-terminus (PTH1-34) of the ligand; the last construction is also secretable due to inclusion of the preproinsulin signal peptide and has been produced as a conditioned medium. EGFP-MK has been produced as a lysate of transfected cells. Using an enzyme-linked immunosorbent assay (ELISA) for GFP, average concentrations of 1.5 and 1670 nmol/L, respectively, of ligand were found in these preparations. The functional properties and potential of these analogs for imaging receptor-expressing cells were examined. Microscopic and cytofluorometric evidence of specific binding and internalization of both fusion proteins was obtained using recipient HEK 293a cells that expressed the cognate recombinant receptor. Endosomal colocalization studies were conducted (Rab5, Rab7, β-arrestin1). Evidence of agonist signaling was obtained (expression of c-Fos, cyclic AMP responsive element (CRE) reporter gene for PTH1-34-EGFP). The constructs PTH1-34-EGFP and EGFP-MK represent bona fide agonists that support the feasibility of transporting protein cargoes inside cells using GPCRs.

  9. ABA signaling in stomatal guard cells: lessons from Commelina and Vicia.

    PubMed

    Mori, Izumi C; Murata, Yoshiyuki

    2011-07-01

    Abscisic acid (ABA) signaling mechanisms have been studied in a broad variety of plant species using complementary analyses, taking advantage of different methodologies suitable for each plant species. Early studies on ABA biosynthesis using Solanum lycopersicum mutants suggested an importance of ABA synthesis in stomatal closure. To understand ABA signaling in guard cells, cellular, biochemical and electrophysiological studies in Vicia faba and Commelina communis have been conducted, providing fundamental knowledge that was further reconfirmed by molecular genetic studies of Arabidopsis. In this article, examples of stomatal studies in several plants and prospects in ABA research are discussed.

  10. Overexpression of soybean miR172c confers tolerance to water deficit and salt stress, but increases ABA sensitivity in transgenic Arabidopsis thaliana.

    PubMed

    Li, Wenbin; Wang, Tao; Zhang, Yuhang; Li, Yongguang

    2016-01-01

    MiRNAs play crucial roles in many aspects of plant development and the response to the environment. The miR172 family has been shown to participate in the control of flowering time and the response to abiotic stress. This family regulates the expression of APETALA2 (AP2)-like transcription factors in Arabidopsis. In the present study, soybean (Glycine max L. Merr.) miR172c, a member of the miR172 family, and its target gene were investigated for abiotic stress responses in transgenic Arabidopsis. gma-miR172c was induced by abscisic acid (ABA) treatments and abiotic stresses, including salt and water deficit. 5'-RACE (5'-rapid amplification of cDNA ends) assays indicated that miR172c directed Glyma01g39520 mRNA cleavage in soybeans. Overexpression of gma-miR172c in Arabidopsis resulted in reduced leaf water loss and increased survival rate under stress conditions. Meanwhile, the root length, germination rate, and cotyledon greening of transgenic plants were improved during both high salt and water deficit conditions. In addition, transgenic plants exhibited hypersensitivity to ABA during both the seed germination and post-germination seedling growth stages. Stress-related physiological indicators and the expression of stress/ABA-responsive genes were affected by abiotic treatments. The overexpression of gma-miR172c in Arabidopsis promoted earlier flowering compared with the wild type through modulation of the expression of flowering genes, such as FT and LFY during long days, especially under drought conditions. Glyma01g39520 weakened ABA sensitivity and reduced the tolerance to drought stress in the snz mutant of Arabidopsis by reducing the expression of ABI3 and ABI5. Overall, the present results demonstrate that gma-miR172c confers water deficit and salt tolerance but increased ABA sensitivity by regulating Glyma01g39520, which also accelerates flowering under abiotic stresses.

  11. Crystal structure of murine coronavirus receptor sCEACAM1a[1,4],a member of the carcinoembtyonic antigen family

    SciTech Connect

    Tan, K.; Zelus, B. D.; Meijers, R.; Liu, J.-H.; Bergelson, J. M.; Zhang, R.; Duke, N.; Joachimiak, A.; Holmes, K. V.; Wang, J.-H.; Biosciences Division; Dana-Farber Cancer Inst.; Harvard Medical School; Univ. of Colorado Health Science Center; Univ. of Pennsylvania School of Medicine

    2002-05-01

    CEACAM1 is a member of the carcinoembryonic antigen (CEA) family. Isoforms of murine CEACAM1 serve as receptors for mouse hepatitis virus (MHV), a murine coronavirus. Here we report the crystal structure of soluble murine sCEACAM1a[1,4], which is composed of two Ig-like domains and has MHV neutralizing activity. Its N-terminal domain has a uniquely folded CC' loop that encompasses key virus-binding residues. This is the first atomic structure of any member of the CEA family, and provides a prototypic architecture for functional exploration of CEA family members. We discuss the structural basis of virus receptor activities of murine CEACAM1 proteins, binding of Neisseria to human CEACAM1, and other homophilic and heterophilic interactions of CEA family members.

  12. CmWRKY1 Enhances the Dehydration Tolerance of Chrysanthemum through the Regulation of ABA-Associated Genes.

    PubMed

    Fan, Qingqing; Song, Aiping; Jiang, Jiafu; Zhang, Ting; Sun, Hainan; Wang, Yinjie; Chen, Sumei; Chen, Fadi

    2016-01-01

    WRKY transcription factors serve as antagonistic or synergistic regulators in a variety of abiotic stress responses in plants. Here, we show that CmWRKY1, a member of the group IIb WRKY family isolated from Chrysanthemum morifolium, exhibits no transcriptional activation in yeast cells. The subcellular localization examination showed that CmWRKY1 localizes to the nucleus in vivo. Furthermore, CmWRKY1-overexpressing transgenic lines exhibit enhanced dehydration tolerance in response to polyethylene glycol (PEG) treatment compared with wild-type plants. We further confirmed that the transgenic plants exhibit suppressed expression levels of genes negatively regulated by ABA, such as PP2C, ABI1 and ABI2, and activated expression levels of genes positively regulated by ABA, such as PYL2, SnRK2.2, ABF4, MYB2, RAB18, and DREB1A. Taken together, our results indicate that CmWRKY1 plays an important role in the response to drought in chrysanthemum through an ABA-mediated pathway. PMID:26938878

  13. CmWRKY1 Enhances the Dehydration Tolerance of Chrysanthemum through the Regulation of ABA-Associated Genes

    PubMed Central

    Fan, Qingqing; Song, Aiping; Jiang, Jiafu; Zhang, Ting; Sun, Hainan; Wang, Yinjie; Chen, Sumei; Chen, Fadi

    2016-01-01

    WRKY transcription factors serve as antagonistic or synergistic regulators in a variety of abiotic stress responses in plants. Here, we show that CmWRKY1, a member of the group IIb WRKY family isolated from Chrysanthemum morifolium, exhibits no transcriptional activation in yeast cells. The subcellular localization examination showed that CmWRKY1 localizes to the nucleus in vivo. Furthermore, CmWRKY1-overexpressing transgenic lines exhibit enhanced dehydration tolerance in response to polyethylene glycol (PEG) treatment compared with wild-type plants. We further confirmed that the transgenic plants exhibit suppressed expression levels of genes negatively regulated by ABA, such as PP2C, ABI1 and ABI2, and activated expression levels of genes positively regulated by ABA, such as PYL2, SnRK2.2, ABF4, MYB2, RAB18, and DREB1A. Taken together, our results indicate that CmWRKY1 plays an important role in the response to drought in chrysanthemum through an ABA-mediated pathway. PMID:26938878

  14. Increased ABA sensitivity results in higher seed dormancy in soft white spring wheat cultivar 'Zak'.

    PubMed

    Schramm, Elizabeth C; Nelson, Sven K; Kidwell, Kimberlee K; Steber, Camille M

    2013-03-01

    As a strategy to increase the seed dormancy of soft white wheat, mutants with increased sensitivity to the plant hormone abscisic acid (ABA) were identified in mutagenized grain of soft white spring wheat "Zak". Lack of seed dormancy is correlated with increased susceptibility to preharvest sprouting in wheat, especially those cultivars with white kernels. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature grain. Three mutant lines called Zak ERA8, Zak ERA19A, and Zak ERA19B (Zak ENHANCED RESPONSE to ABA) were recovered based on failure to germinate on 5 μM ABA. All three mutants resulted in increased ABA sensitivity over a wide range of concentrations such that a phenotype can be detected at very low ABA concentrations. Wheat loses sensitivity to ABA inhibition of germination with extended periods of dry after-ripening. All three mutants recovered required more time to after-ripen sufficiently to germinate in the absence of ABA and to lose sensitivity to 5 μM ABA. However, an increase in ABA sensitivity could be detected after as long as 3 years of after-ripening using high ABA concentrations. The Zak ERA8 line showed the strongest phenotype and segregated as a single semi-dominant mutation. This mutation resulted in no obvious decrease in yield and is a good candidate gene for breeding preharvest sprouting tolerance. PMID:23212773

  15. Glucocorticoid-induced TNF receptor family-related protein ligand regulates the migration of monocytes to the inflamed intestine.

    PubMed

    Liao, Gongxian; van Driel, Boaz; Magelky, Erica; O'Keeffe, Michael S; de Waal Malefyt, Rene; Engel, Pablo; Herzog, Roland W; Mizoguchi, Emiko; Bhan, Atul K; Terhorst, Cox

    2014-01-01

    Glucocorticoid-induced TNF receptor family-related protein (GITR) regulates the function of both T cells and antigen-presenting cells (APCs), while the function of GITR ligand (GITR-L) is largely unknown. Here we evaluate the role of GITR-L, whose expression is restricted to APCs, in the development of enterocolitis. On injecting naive CD4(+) T cells, GITR-L(-/-)Rag(-/-) mice develop a markedly milder colitis than Rag(-/-) mice, which correlates with a 50% reduction of Ly6C(+)CD11b(+)MHCII(+) macrophages in the lamina propria and mesenteric lymph nodes. The same result was observed in αCD40-induced acute colitis and during peritonitis, suggesting an altered monocyte migration. In line with these observations, the number of nondifferentiated monocytes was approximately 3-fold higher in the spleen of GITR-L(-/-)Rag(-/-) mice than in Rag(-/-) mice after αCD40 induction. Consistent with the dynamic change in the formation of an active angiotensin II type 1 receptor (AT1) dimer in GITR-L(-/-) splenic monocytes during intestinal inflammation, the migratory capability of splenic monocytes from GITR-L-deficient mice was impaired in an in vitro transwell migration assay. Conversely, αGITR-L reduces the number of splenic Ly6C(hi) monocytes, concomitantly with an increase in AT1 dimers. We conclude that GITR-L regulates the number of proinflammatory macrophages in sites of inflammation by controlling the egress of monocytes from the splenic reservoir.

  16. CD28 family of receptors on T cells in chronic HBV infection: Expression characteristics, clinical significance and correlations with PD-1 blockade

    PubMed Central

    Tang, Zong-Sheng; Hao, You-Hua; Zhang, E-Juan; Xu, Chun-Li; Zhou, Yun; Zheng, Xin; Yang, Dong-Liang

    2016-01-01

    The aim of the present study was to investigate the overall clinical expression characteristics of the cluster of differentiation (CD)28 family receptors [CD28, inducible T-cell co-stimulator, programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 and B- and T-lymphocyte attenuator] on T cells in patients with chronic hepatitis B (CHB), analyze the correlations among these receptors and the clinical parameters, and to investigate the effects of PD-1 blockade on the receptor expression profiles, T-cell function and other biological effects. The expression characteristics of the CD28 family of receptors, the effects of PD-1 blockade on the receptor expression profiles and the levels of interferon (IFN)-γ were investigated in the T cells of patients with CHB. In addition, the transcription factor, T-box 21 (T-bet) and GATA binding protein 3 (GATA-3) mRNA expression levels were investigated in the peripheral blood mononuclear cells (PBMCs) of patients with CHB. The expression levels of the CD28 family receptors in the T cells of patients with CHB demonstrated distinct characteristics, for example levels of PD-1 and CTLA-4 on CD4 T cells and ICOS, PD-1, and BTLA on CD8 T cells were increased in cells from patients with CHB compared with those from the healthy individuals. A significant positive correlation was demonstrated among the serum HBV DNA titers and the levels of PD-1 on CD8+ T cells with the highest expression of PD-1 corresponding to viral levels >106 IU/ml. A significant positive correlation was observed between the serum HBV DNA titers and the expression levels of BTLA on CD8+ T cells with the highest expression of BTLA corresponding to viral levels >106 IU/ml. PD-1 blockade altered the expression profiles of CD28 family receptors in the T cells of patients with CHB, partly enhanced T cell function and increased the ratio of T-bet/GATA-3 mRNA in PBMCs. Thus, CD28 family receptors are potential clinical indicators for the rapid

  17. Metabotropic NMDA receptor signaling couples Src family kinases to pannexin-1 during excitotoxicity.

    PubMed

    Weilinger, Nicholas L; Lohman, Alexander W; Rakai, Brooke D; Ma, Evelyn M M; Bialecki, Jennifer; Maslieieva, Valentyna; Rilea, Travis; Bandet, Mischa V; Ikuta, Nathan T; Scott, Lucas; Colicos, Michael A; Teskey, G Campbell; Winship, Ian R; Thompson, Roger J

    2016-03-01

    Overactivation of neuronal N-methyl-D-aspartate receptors (NMDARs) causes excitotoxicity and is necessary for neuronal death. In the classical view, these ligand-gated Ca(2+)-permeable ionotropic receptors require co-agonists and membrane depolarization for activation. We report that NMDARs signal during ligand binding without activation of their ion conduction pore. Pharmacological pore block with MK-801, physiological pore block with Mg(2+) or a Ca(2+)-impermeable NMDAR variant prevented NMDAR currents, but did not block excitotoxic dendritic blebbing and secondary currents induced by exogenous NMDA. NMDARs, Src kinase and Panx1 form a signaling complex, and activation of Panx1 required phosphorylation at Y308. Disruption of this NMDAR-Src-Panx1 signaling complex in vitro or in vivo by administration of an interfering peptide either before or 2 h after ischemia or stroke was neuroprotective. Our observations provide insights into a new signaling modality of NMDARs that has broad-reaching implications for brain physiology and pathology.

  18. STC1 interference on calcitonin family of receptors signaling during osteoblastogenesis via adenylate cyclase inhibition.

    PubMed

    Terra, Silvia R; Cardoso, João Carlos R; Félix, Rute C; Martins, Leo Anderson M; Souza, Diogo Onofre G; Guma, Fatima C R; Canário, Adelino Vicente M; Schein, Vanessa

    2015-03-01

    Stanniocalcin 1 (STC1) and calcitonin gene-related peptide (CGRP) are involved in bone formation/remodeling. Here we investigate the effects of STC1 on functional heterodimer complex CALCRL/RAMP1, expression and activity during osteoblastogenesis. STC1 did not modify CALCRL and ramp1 gene expression during osteoblastogenesis when compared to controls. However, plasma membrane spatial distribution of CALCRL/RAMP1 was modified in 7-day pre-osteoblasts exposed to either CGRP or STC1, and both peptides induced CALCRL and RAMP1 assembly. CGRP, but not STC1 stimulated cAMP accumulation in 7-day osteoblasts and in CALCRL/RAMP1 transfected HEK293 cells. Furthermore, STC1 inhibited forskolin stimulated cAMP accumulation of HEK293 cells, but not in CALCRL/RAMP1 transfected HEK293 cells. However, STC1 inhibited cAMP accumulation in calcitonin receptor (CTR) HEK293 transfected cells stimulated by calcitonin. In conclusion, STC1 signals through inhibitory G-protein modulates CGRP receptor spatial localization during osteoblastogenesis and may function as a regulatory factor interacting with calcitonin peptide members during bone formation.

  19. Predicting G-protein-coupled receptors families using different physiochemical properties and pseudo amino acid composition.

    PubMed

    Rehman, Zia-Ur; Mirza, Muhammad Tayyeb; Khan, Asifullah; Xhaard, Henri

    2013-01-01

    G-protein-coupled receptors (GPCRs) initiate signaling pathways via trimetric guanine nucleotide-binding proteins. GPCRs are classified based on their ligand-binding properties and molecular phylogenetic analyses. Nonetheless, these later analyses are in most case dependent on multiple sequence alignments, themselves dependent on human intervention and expertise. Alignment-free classifications of GPCR sequences, in addition to being unbiased, present many applications uncovering hidden physicochemical parameters shared among specific groups of receptors, to being used in automated workflows for large-scale molecular modeling applications. Current alignment-free classification methods, however, do not reach a full accuracy. This chapter discusses how GPCRs amino acid sequences can be classified using pseudo amino acid composition and multiscale energy representation of different physiochemical properties of amino acids. A hybrid feature extraction strategy is shown to be suitable to represent GPCRs and to be able to exploit GPCR amino acid sequence discrimination capability in spatial as well as transform domain. Classification strategies such as support vector machine and probabilistic neural network are then discussed in regards to GPCRs classification. The work of GPCR-Hybrid web predictor is also discussed.

  20. ABA-Cloud: support for collaborative breath research.

    PubMed

    Elsayed, Ibrahim; Ludescher, Thomas; King, Julian; Ager, Clemens; Trosin, Michael; Senocak, Uygar; Brezany, Peter; Feilhauer, Thomas; Amann, Anton

    2013-06-01

    This paper introduces the advanced breath analysis (ABA) platform, an innovative scientific research platform for the entire breath research domain. Within the ABA project, we are investigating novel data management concepts and semantic web technologies to document breath analysis studies for the long run as well as to enable their full automatic reproducibility. We propose several concept taxonomies (a hierarchical order of terms from a glossary of terms), which can be seen as a first step toward the definition of conceptualized terms commonly used by the international community of breath researchers. They build the basis for the development of an ontology (a concept from computer science used for communication between machines and/or humans and representation and reuse of knowledge) dedicated to breath research. PMID:23619467

  1. Rheology and Relaxation Timescales of ABA Triblock Polymer Gels

    NASA Astrophysics Data System (ADS)

    Peters, Andrew; Lodge, Timothy

    When dissolved in a midblock selective solvent, ABA polymers form gels composed of aggregated end block micelles bridged by the midblocks. While much effort has been devoted to the study of the structure of these systems, the dynamics of these systems has received less attention. We examine the underlying mechanism of shear relaxation of ABA triblock polymer gels, especially as a function of chain length, composition, and concentration. Recent work using time-resolved small-angle neutron scattering of polystyrene (PS)-block-poly(ethylene-alt-propylene) (PEP) in squalane has elucidated many aspects of the dynamics of diblock chain exchange. By using rheology to study bulk relaxation phenomena of the triblock equivalent, PS-PEP-PS, we apply the knowledge gained from the chain exchange studies to bridge the gap between the molecular and macroscopic relaxation phenomena in PS-PEP-PS triblock gels.

  2. ABA-Cloud: support for collaborative breath research.

    PubMed

    Elsayed, Ibrahim; Ludescher, Thomas; King, Julian; Ager, Clemens; Trosin, Michael; Senocak, Uygar; Brezany, Peter; Feilhauer, Thomas; Amann, Anton

    2013-06-01

    This paper introduces the advanced breath analysis (ABA) platform, an innovative scientific research platform for the entire breath research domain. Within the ABA project, we are investigating novel data management concepts and semantic web technologies to document breath analysis studies for the long run as well as to enable their full automatic reproducibility. We propose several concept taxonomies (a hierarchical order of terms from a glossary of terms), which can be seen as a first step toward the definition of conceptualized terms commonly used by the international community of breath researchers. They build the basis for the development of an ontology (a concept from computer science used for communication between machines and/or humans and representation and reuse of knowledge) dedicated to breath research.

  3. Modulation of visceral hypersensitivity by glial cell line-derived neurotrophic factor family receptor α-3 in colorectal afferents

    PubMed Central

    Shinoda, M.; Feng, B.; Albers, K. M.; Gebhart, G. F.

    2011-01-01

    Irritable bowel syndrome is characterized by colorectal hypersensitivity and contributed to by sensitized mechanosensitive primary afferents and recruitment of mechanoinsensitive (silent) afferents. Neurotrophic factors are well known to orchestrate dynamic changes in the properties of sensory neurons. Although pain modulation by proteins in the glial cell line-derived neurotrophic factor (GDNF) family has been documented in various pathophysiological states, their role in colorectal hypersensitivity remains unexplored. Therefore, we investigated the involvement of the GDNF family receptor α-3 (GFRα3) signaling in visceral hypersensitivity by quantifying visceromotor responses (VMR) to colorectal distension before and after intracolonic treatment with 2,4,6-trinitrobenzene sulfonic acid (TNBS). Baseline responses to colorectal distension did not differ between C57BL/6 and GFRα3 knockout (KO) mice. Relative to intracolonic saline treatment, TNBS significantly enhanced the VMR to colorectal distension in C57BL/6 mice 2, 7, 10, and 14 days posttreatment, whereas TNBS-induced visceral hypersensitivity was significantly suppressed in GFRα3 KO mice. The proportion of GFRα3 immunopositive thoracolumbar and lumbosacral colorectal dorsal root ganglion neurons was significantly elevated 2 days after TNBS treatment. In single fiber recordings, responses to circumferential stretch of colorectal afferent endings in C57BL/6 mice were significantly increased (sensitized) after exposure to an inflammatory soup, whereas responses to stretch did not sensitize in GFRα3 KO mice. These findings suggest that enhanced GFRα3 signaling in visceral afferents may contribute to development of colorectal hypersensitivity. PMID:21193524

  4. The TAM family receptor tyrosine kinase TYRO3 is a negative regulator of type 2 immunity.

    PubMed

    Chan, Pamela Y; Carrera Silva, Eugenio A; De Kouchkovsky, Dimitri; Joannas, Leonel D; Hao, Liming; Hu, Donglei; Huntsman, Scott; Eng, Celeste; Licona-Limón, Paula; Weinstein, Jason S; Herbert, De'Broski R; Craft, Joseph E; Flavell, Richard A; Repetto, Silvia; Correale, Jorge; Burchard, Esteban G; Torgerson, Dara G; Ghosh, Sourav; Rothlin, Carla V

    2016-04-01

    Host responses against metazoan parasites or an array of environmental substances elicit type 2 immunity. Despite its protective function, type 2 immunity also drives allergic diseases. The mechanisms that regulate the magnitude of the type 2 response remain largely unknown. Here, we show that genetic ablation of a receptor tyrosine kinase encoded byTyro3in mice or the functional neutralization of its ortholog in human dendritic cells resulted in enhanced type 2 immunity. Furthermore, the TYRO3 agonist PROS1 was induced in T cells by the quintessential type 2 cytokine, interleukin-4. T cell-specificPros1knockouts phenocopied the loss ofTyro3 Thus, a PROS1-mediated feedback from adaptive immunity engages a rheostat, TYRO3, on innate immune cells to limit the intensity of type 2 responses.

  5. The TAM family receptor tyrosine kinase TYRO3 is a negative regulator of type 2 immunity

    PubMed Central

    Chan, Pamela Y.; Carrera Silva, Eugenio A.; De Kouchkovsky, Dimitri; Joannas, Leonel D.; Hao, Liming; Hu, Donglei; Huntsman, Scott; Eng, Celeste; Licona-Limón, Paula; Weinstein, Jason S.; Herbert, De’Broski R.; Craft, Joseph E.; Flavell, Richard A.; Repetto, Silvia; Correale, Jorge; Burchard, Esteban G.; Torgerson, Dara G.; Ghosh, Sourav; Rothlin, Carla V.

    2016-01-01

    Host responses against metazoan parasites or an array of environmental substances elicit type 2 immunity. Despite its protective function, type 2 immunity also drives allergic diseases. The mechanisms that regulate the magnitude of the type 2 response remain largely unknown. Here, we show that genetic ablation of a receptor tyrosine kinase encoded by Tyro3 in mice or the functional neutralization of its ortholog in human dendritic cells resulted in enhanced type 2 immunity. Furthermore, the TYRO3 agonist PROS1 was induced in T cells by the quintessential type 2 cytokine, interleukin-4. T cell–specific Pros1 knockouts phenocopied the loss of Tyro3. Thus, a PROS1-mediated feedback from adaptive immunity engages a rheostat, TYRO3, on innate immune cells to limit the intensity of type 2 responses. PMID:27034374

  6. The TAM family receptor tyrosine kinase TYRO3 is a negative regulator of type 2 immunity.

    PubMed

    Chan, Pamela Y; Carrera Silva, Eugenio A; De Kouchkovsky, Dimitri; Joannas, Leonel D; Hao, Liming; Hu, Donglei; Huntsman, Scott; Eng, Celeste; Licona-Limón, Paula; Weinstein, Jason S; Herbert, De'Broski R; Craft, Joseph E; Flavell, Richard A; Repetto, Silvia; Correale, Jorge; Burchard, Esteban G; Torgerson, Dara G; Ghosh, Sourav; Rothlin, Carla V

    2016-04-01

    Host responses against metazoan parasites or an array of environmental substances elicit type 2 immunity. Despite its protective function, type 2 immunity also drives allergic diseases. The mechanisms that regulate the magnitude of the type 2 response remain largely unknown. Here, we show that genetic ablation of a receptor tyrosine kinase encoded byTyro3in mice or the functional neutralization of its ortholog in human dendritic cells resulted in enhanced type 2 immunity. Furthermore, the TYRO3 agonist PROS1 was induced in T cells by the quintessential type 2 cytokine, interleukin-4. T cell-specificPros1knockouts phenocopied the loss ofTyro3 Thus, a PROS1-mediated feedback from adaptive immunity engages a rheostat, TYRO3, on innate immune cells to limit the intensity of type 2 responses. PMID:27034374

  7. Genetic diversity of bitter taste receptor gene family in Sichuan domestic and Tibetan chicken populations.

    PubMed

    Su, Yuan; Li, Diyan; Gaur, Uma; Wang, Yan; Wu, Nan; Chen, Binlong; Xu, Zhongxian; Yin, Huadong; Hu, Yaodong; Zhu, Qing

    2016-09-01

    The sense of bitter taste plays a critical role in animals as it can help them to avoid intake of toxic and harmful substances. Previous research had revealed that chicken has only three bitter taste receptor genes (Tas2r1, Tas2r2 and Tas2r7). To better understand the genetic polymorphisms and importance of bitter taste receptor genes (Tas2rs) in chicken, here, we sequenced Tas2rs of 30 Sichuan domestic chickens and 30 Tibetan chickens. Thirteen single-nucleotide polymorphisms (SNPs) including three nonsynonymous mutations (m.359G>C, m.503C>A and m.583A>G) were detected in Tas2r1 (m. is the abbreviation for mutation); three SNPs were detected in Tas2r2, but none of them were missense mutation; eight SNPs were detected in Tas2r7 including six nonsynonymous substitutions (m.178G>A, m.421A>C, m.787C>T, m.832G>T, m.907A>T and m.943G>A). Tajima's D neutral test indicates that there is no population expansion in both populations, and the size of the population is relatively stable. All the three networks indicate that red jungle fowls share haplotypes with domestic chickens. In addition, we found that haplotypes H1 and HE1 were positively associated with high-altitude adaptation, whereas haplotypes H4 and HE4 showed a negative correlation with high-altitude adaptation in Tas2rs. Although, chicken has only three Tas2rs, our results showed that both Sichuan domestic chickens and Tibetan chickens have abundant haplotypes in Tas2rs, especially in Tas2r7, which might help chickens to recognize a wide variety of bitter-tasting compounds. PMID:27659339

  8. Structure of Natural Killer Receptor 2B4 Bound to CD48 Reveals Basis for Heterophilic Recognition in Signaling Lymphocyte Activation Molecule Family

    SciTech Connect

    Velikovsky,C.; Deng, L.; Chlewicki, L.; Fernandez, M.; Kumar, V.; Mariuzza, R.

    2007-01-01

    Natural killer (NK) cells eliminate virally infected and tumor cells. Among the receptors regulating NK cell function is 2B4 (CD244), a member of the signaling lymphocyte-activation molecule (SLAM) family that binds CD48. 2B4 is the only heterophilic receptor of the SLAM family, whose other members, e.g., NK-T-B-antigen (NTB-A), are self-ligands. We determined the structure of the complex between the N-terminal domains of mouse 2B4 and CD48, as well as the structures of unbound 2B4 and CD48. The complex displayed an association mode related to, yet distinct from, that of the NTB-A dimer. Binding was accompanied by the rigidification of flexible 2B4 regions containing most of the polymorphic residues across different species and receptor isoforms. We propose a model for 2B4-CD48 interactions that permits the intermixing of SLAM receptors with major histocompatibility complex-specific receptors in the NK cell immune synapse. This analysis revealed the basis for heterophilic recognition within the SLAM family.

  9. Six DNA polymorphisms in the low density lipoprotein receptor gene: their genetic relationship and an example of their use for identifying affected relatives of patients with familial hypercholesterolaemia.

    PubMed Central

    Humphries, S; King-Underwood, L; Gudnason, V; Seed, M; Delattre, S; Clavey, V; Fruchart, J C

    1993-01-01

    We have determined the relative allele frequency and estimated linkage disequilibrium between six DNA polymorphisms of the low density lipoprotein (LDL) receptor gene. Polymorphisms were detected using the enzymes SfaNI, TaqI, StuI, HincII, AvaII, and NcoI after DNA amplification by the polymerase chain reaction. Strong linkage disequilibrium was detected between many of the pair wise comparisons in a sample of 60 patients heterozygous for familial hypercholesterolaemia (FH). Using the enzymes HincII, NcoI, and SfaNI, 85% of patients were heterozygous for at least one polymorphism and thus potentially informative for cosegregation studies. The polymorphisms were used to follow the inheritance of the defective allele of the LDL receptor gene in the relatives of a patient with FH. Assays of LDL receptor activity on lymphoblastoid cell lines from two members of the family was used to confirm that the proband, but not the hypercholesterolaemic brother, had a defect in the LDL receptor. In the family, none of the children had inherited the allele of the LDL receptor gene inferred to be defective. The problems associated with this cosegregation approach to identify relatives of patients with a clinical diagnosis of FH are discussed. PMID:8098067

  10. Regulation of the rab17 gene promoter in transgenic Arabidopsis wild-type, ABA-deficient and ABA-insensitive mutants.

    PubMed

    Vilardell, J; Martínez-Zapater, J M; Goday, A; Arenas, C; Pagès, M

    1994-02-01

    The abscisic acid-responsive gene rab17 is induced during maize embryo maturation and in vegetative tissues under water stress conditions. To investigate how ABA is involved in the induction of the rab17 gene, we present here a genetic approach to analyse the transcriptional regulation of the 1.3 kb rab17 promoter fragment in transgenic wild-type Arabidopsis and mutants which are deficient (aba) and insensitive (abi1, abi2 and abi3) to ABA. During seed development the rab17 promoter fragment confers similar temporal and spatial regulation on the reporter gene GUS, both in transgenic wild-type and ABA-deficient and ABA-insensitive mutants. The rab17 promoter was only active in embryo and endosperm during late seed development, although the ABA-deficient embryo mutant showed a reduction in the level of GUS activity. During germination rab17 promoter activity decreases, and GUS activity is not enhanced by water stress in transgenic wild-type and mutant plants. In contrast, transcription of the Arabidopsis endogenous rab gene is stimulated by water stress, both in wild-type and ABA-insensitive mutants. Our data suggest that different molecular mechanisms mediate seed-specific expression and ABA water stress induction of the rab17 gene and indicate strong conservation of the seed-specific regulatory mechanism for rab genes in monocot and dicot plants.

  11. Chromosomal localization of the human natural killer cell class I receptor family genes to 19q13.4 by fluorescence in situ hybridization

    SciTech Connect

    Suto, Yumiko; Maenaka, Katsumi; yabe, Toshio

    1996-07-01

    This report describes the localization of the human natural killer cell I receptor family genes to human chromosome 19q13.4 using fluorescence in situ hybridization. These genes mediate the inhibition of the cytotoxicity of subsets of natural killer cells. 8 refs., 1 fig.

  12. Identification of small molecule agonists of human relaxin family receptor 1 (RXFP1) by utilizing a homogenous cell-based cAMP assay

    PubMed Central

    Chen, Catherine Z.; Southall, Noel; Xiao, Jingbo; Marugan, Juan J.; Ferrer, Marc; Hu, Xin; Jones, Raisa E.; Feng, Shu; Agoulnik, Irina U.

    2016-01-01

    The relaxin hormone is involved in a variety of biological functions including female reproduction and parturition, regulation of cardiovascular, renal, pulmonary, and hepatic functions. It regulates extracellular matrix remodeling, cell invasiveness, proliferation, differentiation, and overall tissue homeostasis. The G protein-coupled receptor (GPCR) RXFP1, relaxin family receptor 1, is a cognate relaxin receptor that mainly signals through cyclic AMP second messenger. While agonists of the receptor could have a wide range of pharmacological utility, up to date, there are no reported small molecule agonists for relaxin receptors. Here, we report the development of quantitative high-throughput platform for RXFP1 agonist screen based on homogenous cell-based HTRF cAMP assay technology. Two small molecules of similar structure were independently identified from a screen of more than 365,677 compounds. Neither compound showed activity in a counter screen with HEK293T cells transfected with an unrelated GPCR vasopressin 1b receptor. These small molecule agonists also demonstrated selectivity against the RXFP2 receptor, providing a basis for future medicinal chemistry optimization of selective relaxin receptor agonists. PMID:23212924

  13. A New Triggering Receptor Expressed on Myeloid Cells (TREM) Family Member, TLT-6, is Involved in Activation and Proliferation of Macrophages

    PubMed Central

    Won, Kyung-Jong; Park, Sung-Won; Lee, Seunghoon; Kong, Il-Keun; Chae, Jung-Il; Kim, Bokyung; Lee, Eun-Jong

    2015-01-01

    The triggering receptor expressed on myeloid cells (TREM) family, which is abundantly expressed in myeloid lineage cells, plays a pivotal role in innate and adaptive immune response. In this study, we aimed to identify a novel receptor expressed on hematopoietic stem cells (HSCs) by using in silico bioinformatics and to characterize the identified receptor. We thus found the TREM-like transcript (TLT)-6, a new member of TREM family. TLT-6 has a single immunoglobulin domain in the extracellular region and a long cytoplasmic region containing 2 immunoreceptor tyrosine-based inhibitory motif-like domains. TLT-6 transcript was expressed in HSCs, monocytes and macrophages. TLT-6 protein was up-regulated on the surface of bone marrow-derived and peritoneal macrophages by lipopolysaccharide stimulation. TLT-6 exerted anti-proliferative effects in macrophages. Our results demonstrate that TLT-6 may regulate the activation and proliferation of macrophages. PMID:26557807

  14. Importance of ABA homeostasis under terminal drought stress in regulating grain filling events.

    PubMed

    Govind, Geetha; Seiler, Christiane; Wobus, Ulrich; Sreenivasulu, Nese

    2011-08-01

    Recent studies suggest that abscisic acid (ABA) at its basal level plays an important role during seed set and grain filling events. Under drought stress ABA levels were found to be significantly enhanced in the developing seed. Until now we lack an understanding of (A) ABA homeostasis in developing seeds under terminal drought and (B) the interactive role of ABA in regulating the starch biosynthesis pathway in developing grains under terminal drought. We have recently reported the possible regulation of ABA homeostasis in source (flag leaf) and sink (developing grains) tissues under post-anthesis drought stress in barley and concluded that significantly enhanced ABA levels in developing grains are due to strong activation of the ABA deconjugation pathway and fine regulation of the ABA biosynthesis-degradation pathway.1 Additionally, we provided evidence for the role of ABA in differential regulation of starch biosynthesis genes and a significant upregulation of starch degradation beta amylase genes under drought, i.e. ABA not only influences the rate of starch accumulation but also starch quality.

  15. Membrane-associated transcription factor peptidase, site-2 protease, antagonizes ABA signaling in Arabidopsis.

    PubMed

    Zhou, Shun-Fan; Sun, Le; Valdés, Ana Elisa; Engström, Peter; Song, Ze-Ting; Lu, Sun-Jie; Liu, Jian-Xiang

    2015-10-01

    Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood. We functionally characterized the role of membrane-associated transcription factor peptidase, site-2 protease (S2P), in ABA signaling during seed germination in Arabidopsis. Genetic analysis showed that loss-of-function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane-associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen-facing C-terminus were deleted, in the S2P mutant rescued its ABA-sensitive phenotype. MYC and green fluorescent protein (GFP)-tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up-regulated in seeds of the wild-type upon ABA treatment; this up-regulation was impaired in seeds of S2P mutants. Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane-associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling. PMID:25919792

  16. Comprehensive Analysis of ABA Effects on Ethylene Biosynthesis and Signaling during Tomato Fruit Ripening

    PubMed Central

    Bu, Jianwen; Jiang, Yuanyuan; Khan, Zia Ullah; Luo, Zisheng; Mao, Linchun; Ying, Tiejin

    2016-01-01

    ABA has been widely acknowledged to regulate ethylene biosynthesis and signaling during fruit ripening, but the molecular mechanism underlying the interaction between these two hormones are largely unexplored. In the present study, exogenous ABA treatment obviously promoted fruit ripening as well as ethylene emission, whereas NDGA (Nordihydroguaiaretic acid, an inhibitor of ABA biosynthesis) application showed the opposite biological effects. Combined RNA-seq with time-course RT-PCR analysis, our study not only helped to illustrate how ABA regulated itself at the transcription level, but also revealed that ABA can facilitate ethylene production and response probably by regulating some crucial genes such as LeACS4, LeACO1, GR and LeETR6. In addition, investigation on the fruits treated with 1-MCP immediately after ABA exposure revealed that ethylene might be essential for the induction of ABA biosynthesis and signaling at the onset of fruit ripening. Furthermore, some specific transcription factors (TFs) known as regulators of ethylene synthesis and sensibility (e.g. MADS-RIN, TAGL1, CNR and NOR) were also observed to be ABA responsive, which implied that ABA influenced ethylene action possibly through the regulation of these TFs expression. Our comprehensive physiological and molecular-level analysis shed light on the mechanism of cross-talk between ABA and ethylene during the process of tomato fruit ripening. PMID:27100326

  17. Abscisic acid (ABA) sensitivity regulates desiccation tolerance in germinated Arabidopsis seeds.

    PubMed

    Maia, Julio; Dekkers, Bas J W; Dolle, Miranda J; Ligterink, Wilco; Hilhorst, Henk W M

    2014-07-01

    During germination, orthodox seeds lose their desiccation tolerance (DT) and become sensitive to extreme drying. Yet, DT can be rescued, in a well-defined developmental window, by the application of a mild osmotic stress before dehydration. A role for abscisic acid (ABA) has been implicated in this stress response and in DT re-establishment. However, the path from the sensing of an osmotic cue and its signaling to DT re-establishment is still largely unknown. Analyses of DT, ABA sensitivity, ABA content and gene expression were performed in desiccation-sensitive (DS) and desiccation-tolerant Arabidopsis thaliana seeds. Furthermore, loss and re-establishment of DT in germinated Arabidopsis seeds was studied in ABA-deficient and ABA-insensitive mutants. We demonstrate that the developmental window in which DT can be re-established correlates strongly with the window in which ABA sensitivity is still present. Using ABA biosynthesis and signaling mutants, we show that this hormone plays a key role in DT re-establishment. Surprisingly, re-establishment of DT depends on the modulation of ABA sensitivity rather than enhanced ABA content. In addition, the evaluation of several ABA-insensitive mutants, which can still produce normal desiccation-tolerant seeds, but are impaired in the re-establishment of DT, shows that the acquisition of DT during seed development is genetically different from its re-establishment during germination.

  18. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination

    PubMed Central

    Arc, Erwann; Sechet, Julien; Corbineau, Françoise; Rajjou, Loïc; Marion-Poll, Annie

    2013-01-01

    Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8′-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8′-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination. PMID:23531630

  19. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination.

    PubMed

    Arc, Erwann; Sechet, Julien; Corbineau, Françoise; Rajjou, Loïc; Marion-Poll, Annie

    2013-01-01

    Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8'-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8'-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.

  20. Conserved signaling through vascular endothelial growth (VEGF) receptor family members in murine lymphatic endothelial cells.

    PubMed

    Coso, Sanja; Zeng, Yiping; Sooraj, Dhanya; Williams, Elizabeth D

    2011-10-15

    Lymphatic vessels guide interstitial fluid, modulate immune responses by regulating leukocyte and antigen trafficking to lymph nodes, and in a cancer setting enable tumor cells to track to regional lymph nodes. The aim of the study was to determine whether primary murine lymphatic endothelial cells (mLECs) show conserved vascular endothelial growth factor (VEGF) signaling pathways with human LECs (hLECs). LECs were successfully isolated from murine dermis and prostate. Similar to hLECs, vascular endothelial growth factor (VEGF) family ligands activated MAPK and pAkt intracellular signaling pathways in mLECs. We describe a robust protocol for isolation of mLECs which, by harnessing the power of transgenic and knockout mouse models, will be a useful tool to study how LEC phenotype contributes to alterations in lymphatic vessel formation and function.

  1. Friedrich Miescher Prize awardee lecture review. A conserved family of nuclear export receptors mediates the exit of messenger RNA to the cytoplasm.

    PubMed

    Izaurralde, E

    2001-07-01

    The distinguishing feature of eukaryotic cells is the segregation of RNA biogenesis and DNA replication in the nucleus, separate from the cytoplasmic machinery for protein synthesis. As a consequence, messenger RNAs (mRNAs) and all cytoplasmic RNAs from nuclear origin need to be transported from their site of synthesis in the nucleus to their final cytoplasmic destination. Nuclear export occurs through nuclear pore complexes (NPCs) and is mediated by saturable transport receptors, which shuttle between the nucleus and cytoplasm. The past years have seen great progress in the characterization of the mRNA export pathway and the identification of proteins involved in this process. A novel family of nuclear export receptors (the NXF family), distinct from the well-characterized family of importin beta-like proteins, has been implicated in the export of mRNA to the cytoplasm.

  2. Friedrich Miescher Prize awardee lecture review. A conserved family of nuclear export receptors mediates the exit of messenger RNA to the cytoplasm.

    PubMed

    Izaurralde, E

    2001-07-01

    The distinguishing feature of eukaryotic cells is the segregation of RNA biogenesis and DNA replication in the nucleus, separate from the cytoplasmic machinery for protein synthesis. As a consequence, messenger RNAs (mRNAs) and all cytoplasmic RNAs from nuclear origin need to be transported from their site of synthesis in the nucleus to their final cytoplasmic destination. Nuclear export occurs through nuclear pore complexes (NPCs) and is mediated by saturable transport receptors, which shuttle between the nucleus and cytoplasm. The past years have seen great progress in the characterization of the mRNA export pathway and the identification of proteins involved in this process. A novel family of nuclear export receptors (the NXF family), distinct from the well-characterized family of importin beta-like proteins, has been implicated in the export of mRNA to the cytoplasm. PMID:11529502

  3. Families of Nuclear Receptors in Vertebrate Models: Characteristic and Comparative Toxicological Perspective

    PubMed Central

    Zhao, Yanbin; Zhang, Kun; Giesy, John P.; Hu, Jianying

    2015-01-01

    Various synthetic chemicals are ligands for nuclear receptors (NRs) and can cause adverse effects in vertebrates mediated by NRs. While several model vertebrates, such as mouse, chicken, western clawed frog and zebrafish, are widely used in toxicity testing, few NRs have been well described for most of these classes. In this report, NRs in genomes of 12 vertebrates are characterized via bioinformatics approaches. Although numbers of NRs varied among species, with 40–42 genes in birds to 66–74 genes in teleost fishes, all NRs had clear homologs in human and could be categorized into seven subfamilies defined as NR0B-NR6A. Phylogenetic analysis revealed conservative evolutionary relationships for most NRs, which were consistent with traditional morphology-based systematics, except for some exceptions in Dolphin (Tursiops truncatus). Evolution of PXR and CAR exhibited unexpected multiple patterns and the existence of CAR possibly being traced back to ancient lobe-finned fishes and tetrapods (Sarcopterygii). Compared to the more conservative DBD of NRs, sequences of LBD were less conserved: Sequences of THRs, RARs and RXRs were ≥90% similar to those of the human, ERs, AR, GR, ERRs and PPARs were more variable with similarities of 60%–100% and PXR, CAR, DAX1 and SHP were least conserved among species. PMID:25711679

  4. Families of Nuclear Receptors in Vertebrate Models: Characteristic and Comparative Toxicological Perspective

    NASA Astrophysics Data System (ADS)

    Zhao, Yanbin; Zhang, Kun; Giesy, John P.; Hu, Jianying

    2015-02-01

    Various synthetic chemicals are ligands for nuclear receptors (NRs) and can cause adverse effects in vertebrates mediated by NRs. While several model vertebrates, such as mouse, chicken, western clawed frog and zebrafish, are widely used in toxicity testing, few NRs have been well described for most of these classes. In this report, NRs in genomes of 12 vertebrates are characterized via bioinformatics approaches. Although numbers of NRs varied among species, with 40-42 genes in birds to 66-74 genes in teleost fishes, all NRs had clear homologs in human and could be categorized into seven subfamilies defined as NR0B-NR6A. Phylogenetic analysis revealed conservative evolutionary relationships for most NRs, which were consistent with traditional morphology-based systematics, except for some exceptions in Dolphin (Tursiops truncatus). Evolution of PXR and CAR exhibited unexpected multiple patterns and the existence of CAR possibly being traced back to ancient lobe-finned fishes and tetrapods (Sarcopterygii). Compared to the more conservative DBD of NRs, sequences of LBD were less conserved: Sequences of THRs, RARs and RXRs were >=90% similar to those of the human, ERs, AR, GR, ERRs and PPARs were more variable with similarities of 60%-100% and PXR, CAR, DAX1 and SHP were least conserved among species.

  5. Venomous secretions from marine snails of the Terebridae family target acetylcholine receptors.

    PubMed

    Kendel, Yvonne; Melaun, Christian; Kurz, Alexander; Nicke, Annette; Peigneur, Steve; Tytgat, Jan; Wunder, Cora; Mebs, Dietrich; Kauferstein, Silke

    2013-05-21

    Venoms from cone snails (Conidae) have been extensively studied during the last decades, but those from other members of the suborder Toxoglossa, such as of Terebridae and Turridae superfamilies attracted less interest so far. Here, we report the effects of venom and gland extracts from three species of the superfamily Terebridae. By 2-electrode voltage-clamp technique the gland extracts were tested on Xenopus oocytes expressing nicotinic acetylcholine receptors (nAChRs) of rat neuronal (α3β2, α3β4, α4β2, α4β4, α7) and muscle subtypes (α1β1γδ), and expressing potassium (Kv1.2 and Kv1.3) and sodium channels (Nav1.2, 1.3, 1.4, 1.6). The extracts were shown to exhibit remarkably high inhibitory activities on almost all nAChRs tested, in particular on the α7 subtype suggesting the presence of peptides of the A-superfamily from the venom of Conus species. In contrast, no effects on the potassium and sodium channels tested were observed. The venoms of terebrid snails may offer an additional source of novel biologically active peptides.

  6. Ligand-receptor binding revealed by the TNF family member TALL-1.

    SciTech Connect

    Liu, Y. F.; Hong, X.; Kappler, J.; Jiang, L.; Zhang, R. G.; Xu, L. G.; Pan, C.-H.; Martin, W. E.; Murphy, R. C.; Shu, H.-B.; Dai, S. D.; Zhang, G. Y.; Biosciences Division; National Jewish Medical and Research Center; Howard Hughes Medical Inst.; Univ. of Colorado Health Science Center; Peking Univ.

    2003-05-01

    The tumour necrosis factor (TNF) ligand TALL-1 and its cognate receptors, BCMA, TACI and BAFF-R, were recently identified as members of the TNF superfamily, which are essential factors contributing to B-cell maturation. The functional, soluble fragment of TALL-1 (sTALL-1) forms a virus-like assembly for its proper function. Here we determine the crystal structures of sTALL-1 complexed with the extracellular domains of BCMA and BAFF-R at 2.6 and 2.5 {angstrom}, respectively. The single cysteine-rich domain of BCMA and BAFF-R both have saddle-like architectures, which sit on the horseback-like surface formed by four coil regions on each individual sTALL-1 monomer. Three novel structural modules, D2, X2 and N, were revealed from the current structures. Sequence alignments, structural modelling and mutagenesis revealed that one disulphide bridge in BAFF-R is critical for determining the binding specificity of the extracellular domain eBAFF-R to TALL-1 instead of APRIL, a closely related ligand of TALL-1, which was confirmed by binding experiments in vitro.

  7. A novel mutation of the adrenocorticotropin receptor (ACTH-R) gene in a family with the syndrome of isolated glucocorticoid deficiency, but no ACTH-R abnormalities in two families with the triple A syndrome

    SciTech Connect

    Tsigos, C.; Arai, K.; Latronico, A.C. ||

    1995-07-01

    Isolated glucocorticoid deficiency (IGD) is an autosomal recessive disorder characterized by primary adrenocortical insufficiency, usually without mineralocorticoid deficiency. Occasionally, the disorder is associated with alacrima and achalasia of the esophagus (triple A syndrome), suggesting potential heterogeneity in its etiology. Mutations in the ACTH receptor gene have been reported in several families with IGD. We have amplified and directly sequenced the entire intronless ACTH receptor gene in 1 other family with IGD and 2 famlies with triple A syndrome. The proband with IGD was a homozygote for an A {r_arrow}G substitution, changing tyrosine 254 to cysteine in the third extracellular loop of the receptor protein, probably interfering with ligand binding. Both of her parents were heterozygotes for this mutation, which was not detected in 100 normal alleles. No mutations were identified in the entire coding area of the ACTH receptor in the 2 families with triple A syndrome, supporting the idea of a developmental or postreceptor defect in this syndrome. 19 refs., 1 fig.

  8. The Transient Receptor Potential (TRP) Channel Family in Colletotrichum graminicola: A Molecular and Physiological Analysis

    PubMed Central

    Lange, Mario; Weihmann, Fabian; Schliebner, Ivo; Horbach, Ralf; Deising, Holger B.; Wirsel, Stefan G. R.

    2016-01-01

    Calcium (Ca2+) is a universal second messenger in all higher organisms and centrally involved in the launch of responses to environmental stimuli. Ca2+ signals in the cytosol are initiated by the activation of Ca2+ channels in the plasma membrane and/or in endomembranes. Yeast (Saccharomyces cerevisiae) contains a Ca2+-permeable channel of the TRP family, TRPY1, which is localized in the vacuolar membrane and contributes to cytosolic free Ca2+ ([Ca2+]cyt) elevations, for example in response to osmotic upshock. A TRPY1 homologue in the rice blast fungus is known to be important for growth and pathogenicity. To determine the role of the TRP channel family in the maize pathogen Colletotrichum graminicola, proteins homologous to TRPY1 were searched. This identified not one, but four genes in the C. graminicola genome, which had putative orthologs in other fungi, and which we named CgTRPF1 through 4. The topology of the CgTRPF proteins resembled that of TRPY1, albeit with a variable number of transmembrane (TM) domains additional to the six-TM-domain core and a diverse arrangement of putatively Ca2+-binding acidic motifs. All CgTRPF genes were expressed in axenic culture and throughout the infection of maize. Like TRPY1, all TRPF proteins of C. graminicola were localized intracellularly, albeit three of them were found not in large vacuoles, but co-localized in vesicular structures. Deletion strains for the CgTRPF genes were not altered in processes thought to involve Ca2+ release from internal stores, i.e. spore germination, the utilization of complex carbon sources, and the generation of tip-focussed [Ca2+]cyt spikes. Heterologous expression of CgTRPF1 through 4 in a tryp1Δ yeast mutant revealed that none of the channels mediated the release of Ca2+ in response to osmotic upshock. Accordingly, aequorin-based [Ca2+]cyt measurements of C. graminicola showed that in this fungus, osmotic upshock-triggered [Ca2+]cyt elevations were generated entirely by influx of Ca2

  9. The Transient Receptor Potential (TRP) Channel Family in Colletotrichum graminicola: A Molecular and Physiological Analysis.

    PubMed

    Lange, Mario; Weihmann, Fabian; Schliebner, Ivo; Horbach, Ralf; Deising, Holger B; Wirsel, Stefan G R; Peiter, Edgar

    2016-01-01

    Calcium (Ca2+) is a universal second messenger in all higher organisms and centrally involved in the launch of responses to environmental stimuli. Ca2+ signals in the cytosol are initiated by the activation of Ca2+ channels in the plasma membrane and/or in endomembranes. Yeast (Saccharomyces cerevisiae) contains a Ca2+-permeable channel of the TRP family, TRPY1, which is localized in the vacuolar membrane and contributes to cytosolic free Ca2+ ([Ca2+]cyt) elevations, for example in response to osmotic upshock. A TRPY1 homologue in the rice blast fungus is known to be important for growth and pathogenicity. To determine the role of the TRP channel family in the maize pathogen Colletotrichum graminicola, proteins homologous to TRPY1 were searched. This identified not one, but four genes in the C. graminicola genome, which had putative orthologs in other fungi, and which we named CgTRPF1 through 4. The topology of the CgTRPF proteins resembled that of TRPY1, albeit with a variable number of transmembrane (TM) domains additional to the six-TM-domain core and a diverse arrangement of putatively Ca2+-binding acidic motifs. All CgTRPF genes were expressed in axenic culture and throughout the infection of maize. Like TRPY1, all TRPF proteins of C. graminicola were localized intracellularly, albeit three of them were found not in large vacuoles, but co-localized in vesicular structures. Deletion strains for the CgTRPF genes were not altered in processes thought to involve Ca2+ release from internal stores, i.e. spore germination, the utilization of complex carbon sources, and the generation of tip-focussed [Ca2+]cyt spikes. Heterologous expression of CgTRPF1 through 4 in a tryp1Δ yeast mutant revealed that none of the channels mediated the release of Ca2+ in response to osmotic upshock. Accordingly, aequorin-based [Ca2+]cyt measurements of C. graminicola showed that in this fungus, osmotic upshock-triggered [Ca2+]cyt elevations were generated entirely by influx of Ca2

  10. Mechanism for insulin-like peptide 5 distinguishing the homologous relaxin family peptide receptor 3 and 4

    PubMed Central

    Hu, Meng-Jun; Shao, Xiao-Xia; Wang, Jia-Hui; Wei, Dian; Guo, Yu-Qi; Liu, Ya-Li; Xu, Zeng-Guang; Guo, Zhan-Yun

    2016-01-01

    The relaxin family peptides play a variety of biological functions by activating four G protein-coupled receptors, RXFP1–4. Among them, insulin-like peptide 5 (INSL5) and relaxin-3 share the highest sequence homology, but they have distinct receptor preference: INSL5 can activate RXFP4 only, while relaxin-3 can activate RXFP3, RXFP4, and RXFP1. Previous studies suggest that the A-chain is responsible for their different selectivity for RXFP1. However, the mechanism by which INSL5 distinguishes the homologous RXFP4 and RXFP3 remains unknown. In the present work, we chemically evolved INSL5 in vitro to a strong agonist of both RXFP4 and RXFP3 through replacement of its five B-chain residues with the corresponding residues of relaxin-3. We identified four determinants (B2Glu, B9Leu, B17Tyr, and a rigid B-chain C-terminus) on INSL5 that are responsible for its inactivity at RXFP3. In reverse experiments, we grafted these determinants onto a chimeric R3/I5 peptide, which contains the B-chain of relaxin-3 and the A-chain of INSL5, and retains full activation potency at RXFP3 and RXFP4. All resultant R3/I5 mutants retained high activation potency towards RXFP4, but most displayed significantly decreased or even abolished activation potency towards RXFP3, confirming the role of these four INSL5 determinants in distinguishing RXFP4 from RXFP3. PMID:27404393

  11. Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua

    PubMed Central

    2012-01-01

    Background Toll-like receptors (Tlrs) are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua) is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. Results In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. Conclusion Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs. PMID:23273344

  12. The alpha1-fetoprotein locus is activated by a nuclear receptor of the Drosophila FTZ-F1 family.

    PubMed

    Galarneau, L; Paré, J F; Allard, D; Hamel, D; Levesque, L; Tugwood, J D; Green, S; Bélanger, L

    1996-07-01

    The alpha1-fetoprotein (AFP) gene is located between the albumin and alpha-albumin genes and is activated by transcription factor FTF (fetoprotein transcription factor), presumed to transduce early developmental signals to the albumin gene cluster. We have identified FTF as an orphan nuclear receptor of the Drosophila FTZ-F1 family. FTF recognizes the DNA sequence 5'-TCAAGGTCA-3', the canonical recognition motif for FTZ-F1 receptors. cDNA sequence homologies indicate that rat FTF is the ortholog of mouse LRH-1 and Xenopus xFF1rA. Rodent FTF is encoded by a single-copy gene, related to the gene encoding steroidogenic factor 1 (SF-1). The 5.2-kb FTF transcript is translated from several in-frame initiator codons into FTF isoforms (54 to 64 kDa) which appear to bind DNA as monomers, with no need for a specific ligand, similar KdS (approximately equal 3 x 10(-10) M), and similar transcriptional effects. FTF activates the AFP promoter without the use of an amino-terminal activation domain; carboxy-terminus-truncated FTF exerts strong dominant negative effects. In the AFP promoter, FTF recruits an accessory trans-activator which imparts glucocorticoid reactivity upon the AFP gene. FTF binding sites are found in the promoters of other liver-expressed genes, some encoding liver transcription factors; FTF, liver alpha1-antitrypsin promoter factor LFB2, and HNF-3beta promoter factor UF2-H3beta are probably the same factor. FTF is also abundantly expressed in the pancreas and may exert differentiation functions in endodermal sublineages, similar to SF-1 in steroidogenic tissues. HepG2 hepatoma cells seem to express a mutated form of FTF.

  13. MBF1s regulate ABA-dependent germination of Arabidopsis seeds.

    PubMed

    Di Mauro, María Florencia; Iglesias, María José; Arce, Débora Pamela; Valle, Estela Marta; Arnold, Roberto Benech; Tsuda, Kenichi; Yamazaki, Ken-ichi; Casalongué, Claudia Anahí; Godoy, Andrea Verónica

    2012-02-01

    Transcriptional co-activators of the multiprotein bridging factor 1 (MBF1) controls gene expression by connecting transcription factors and the basal transcription machinery. In Arabidopsis thaliana functions of MBF1 genes have been related to stress tolerance and developmental alterations. Endogenous ABA plays a major role in the regulation of Arabidopsis seed dormancy and germination. Seed dormancy and ABA sensitivity are enhanced in ethylene insensitive mutants suggesting that ethylene signal transduction pathway is necessary to fully develop ABA-dependent germination. In this report we showed that a triple knock-down mutant for Arabidopsis MBF1 genes (abc-) has enhanced seed dormancy and displays hypersensitivity to exogenous ABA. In addition, higher ABA contents were detected in abc- seeds after imbibition. These evidences suggest a negative role of MBF1s genes in ABA-dependent inhibition of germination. The participation of MBF1s in ethylene signal transduction pathway is also discussed.

  14. TIM genes: a family of cell surface phosphatidylserine receptors that regulate innate and adaptive immunity

    PubMed Central

    Freeman, Gordon J.; Casasnovas, Jose M.; Umetsu, Dale T.; DeKruyff, Rosemarie H.

    2010-01-01

    Summary The TIM (T cell/transmembrane, immunoglobulin, and mucin) gene family plays a critical role in regulating immune responses, including allergy, asthma, transplant tolerance, autoimmunity, and the response to viral infections. The unique structure of TIM immunoglobulin variable region domains allows highly specific recognition of phosphatidylserine (PtdSer), exposed on the surface of apoptotic cells. TIM-1, TIM-3, and TIM-4 all recognize PtdSer but differ in expression, suggesting that they have distinct functions in regulating immune responses. TIM-1, an important susceptibility gene for asthma and allergy, is preferentially expressed on T-helper 2 (Th2) cells and functions as a potent costimulatory molecule for T-cell activation. TIM-3 is preferentially expressed on Th1 and Tc1 cells, and generates an inhibitory signal resulting in apoptosis of Th1 and Tc1 cells. TIM-3 is also expressed on some dendritic cells and can mediate phagocytosis of apoptotic cells and cross-presentation of antigen. In contrast, TIM-4 is exclusively expressed on antigen-presenting cells, where it mediates phagocytosis of apoptotic cells and plays an important role in maintaining tolerance. TIM molecules thus provide a functional repertoire for recognition of apoptotic cells, which determines whether apoptotic cell recognition leads to immune activation or tolerance, depending on the TIM molecule engaged and the cell type on which it is expressed. PMID:20536563

  15. Acidic Amino Acids Impart Enhanced Ca2+ Permeability and Flux in Two Members of the ATP-gated P2X Receptor Family

    PubMed Central

    Samways, Damien S.K.; Egan, Terrance M.

    2007-01-01

    P2X receptors are ATP-gated cation channels expressed in nerve, muscle, bone, glands, and the immune system. The seven family members display variable Ca2+ permeabilities that are amongst the highest of all ligand-gated channels (Egan and Khakh, 2004). We previously reported that polar residues regulate the Ca2+ permeability of the P2X2 receptor (Migita et al., 2001). Here, we test the hypothesis that the formal charge of acidic amino acids underlies the higher fractional Ca2+ currents (Pf%) of the rat and human P2X1 and P2X4 subtypes. We used patch-clamp photometry to measure the Pf% of HEK-293 cells transiently expressing a range of wild-type and genetically altered receptors. Lowering the pH of the extracellular solution reduced the higher Pf% of the P2X1 receptor but had no effect on the lower Pf% of the P2X2 receptor, suggesting that ionized side chains regulate the Ca2+ flux of some family members. Removing the fixed negative charges found at the extracellular ends of the transmembrane domains also reduced the higher Pf% of P2X1 and P2X4 receptors, and introducing these charges at homologous positions increased the lower Pf% of the P2X2 receptor. Taken together, the data suggest that COO− side chains provide an electrostatic force that interacts with Ca2+ in the mouth of the pore. Surprisingly, the glutamate residue that is partly responsible for the higher Pf% of the P2X1 and P2X4 receptors is conserved in the P2X3 receptor that has the lowest Pf% of all family members. We found that neutralizing an upstream His45 increased Pf% of the P2X3 channel, suggesting that this positive charge masks the facilitation of Ca2+ flux by the neighboring Glu46. The data support the hypothesis that formal charges near the extracellular ends of transmembrane domains contribute to the high Ca2+ permeability and flux of some P2X receptors. PMID:17325195

  16. A single amino acid substitution in the exoplasmic domain of the human growth hormone (GH) receptor confers familial GH resistance (Laron syndrome) with positive GH-binding activity by abolishing receptor homodimerization.

    PubMed Central

    Duquesnoy, P; Sobrier, M L; Duriez, B; Dastot, F; Buchanan, C R; Savage, M O; Preece, M A; Craescu, C T; Blouquit, Y; Goossens, M

    1994-01-01

    Growth hormone (GH) elicits a variety of biological activities mainly mediated by the GH receptor (GHR), a transmembrane protein that, based on in vitro studies, seemed to function as a homodimer. To test this hypothesis directly, we investigated patients displaying the classic features of Laron syndrome (familial GH resistance characterized by severe dwarfism and metabolic dysfunction), except for the presence of normal binding activity of the plasma GH-binding protein, a molecule that derives from the exoplasmic-coding domain of the GHR gene. In two unrelated families, the same GHR mutation was identified, resulting in the substitution of a highly conserved aspartate residue by histidine at position 152 (D152H) of the exoplasmic domain, within the postulated interface sequence involved in homodimerization. The recombinant mutated receptor protein was correctly expressed at the plasma membrane. It displayed subnormal GH-binding activity, a finding in agreement with the X-ray crystal structure data inferring this aspartate residue outside the GH-binding domain. However, mAb-based studies suggested the critical role of aspartate 152 in the proper folding of the interface area. We show that a recombinant soluble form of the mutant receptor is unable to dimerize, the D152H substitution also preventing the formation of heterodimers of wild-type and mutant molecules. These results provide in vivo evidence that monomeric receptors are inactive and that receptor dimerization is involved in the primary signalling of the GH-associated growth-promoting and metabolic actions. Images PMID:8137822

  17. Root ABA Accumulation in Long-Term Water-Stressed Plants is Sustained by Hormone Transport from Aerial Organs.

    PubMed

    Manzi, Matías; Lado, Joanna; Rodrigo, María Jesús; Zacarías, Lorenzo; Arbona, Vicent; Gómez-Cadenas, Aurelio

    2015-12-01

    The reduced pool of the ABA precursors, β,β-carotenoids, in roots does not account for the substantial increase in ABA content in response to water stress (WS) conditions, suggesting that ABA could be transported from other organs. Basipetal transport was interrupted by stem-girdling, and ABA levels were determined in roots after two cycles of WS induced by transplanting plants to dry perlite. Leaf applications of isotope-labeled ABA and reciprocal grafting of ABA-deficient tomato mutants were used to confirm the involvement of aerial organs on root ABA accumulation. Disruption of basipetal transport reduced ABA accumulation in roots, and this decrease was more severe after two consecutive WS periods. This effect was linked to a sharp decrease in the β,β-carotenoid pool in roots in response to water deficit. Significant levels of isotope-labeled ABA were transported from leaves to roots, mainly in plants subjected to water dehydration. Furthermore, the use of different ABA-deficient tomato mutants in reciprocal grafting combinations with wild-type genotypes confirmed the involvement of aerial organs in the ABA accumulation in roots. In conclusion, accumulation of ABA in roots after long-term WS periods largely relies on the aerial organs, suggesting a reduced ability of the roots to synthesize ABA from carotenoids. Furthermore, plants are able to transport ABA basipetally to sustain high hormone levels in roots.

  18. Ethylene-dependent/ethylene-independent ABA regulation of tomato plants colonized by arbuscular mycorrhiza fungi.

    PubMed

    Martín-Rodríguez, José Ángel; León-Morcillo, Rafael; Vierheilig, Horst; Ocampo, Juan Antonio; Ludwig-Müller, Jutta; García-Garrido, José Manuel

    2011-04-01

    We investigated the relationship between ABA and ethylene regulating the formation of the arbuscular mycorrhiza (AM) symbiosis in tomato (Solanum lycopersicum) plants and tried to define the specific roles played by each of these phytohormones in the mycorrhization process. We analysed the impact of ABA biosynthesis inhibition on mycorrhization by Glomus intraradices in transgenic tomato plants with an altered ethylene pathway. We also studied the effects on mycorrhization in sitiens plants treated with the aminoethoxyvinyl glycine hydrochloride (AVG) ethylene biosynthesis inhibitor and supplemented with ABA. In addition, the expression of plant and fungal genes involved in the mycorrhization process was studied. ABA biosynthesis inhibition qualitatively altered the parameters of mycorrhization in accordance with the plant's ethylene perception and ethylene biosynthesis abilities. Inhibition of ABA biosynthesis in wild-type plants negatively affected all the mycorrhization parameters studied, while tomato mutants impaired in ethylene synthesis only showed a reduced arbuscular abundance in mycorrhizal roots. Inhibition of ethylene synthesis in ABA-deficient sitiens plants increased the intensity of mycorrhiza development, while ABA application rescued arbuscule abundance in the root's mycorrhizal zones. The results of our study show an antagonistic interaction between ABA and ethylene, and different roles of each of the two hormones during AM formation. This suggests that a dual ethylene-dependent/ethylene-independent mechanism is involved in ABA regulation of AM formation.

  19. The site of water stress governs the pattern of ABA synthesis and transport in peanut

    PubMed Central

    Hu, Bo; Cao, Jiajia; Ge, Kui; Li, Ling

    2016-01-01

    Abscisic acid (ABA) is one of the most important phytohormones involved in stress responses in plants. However, knowledge of the effect on ABA distribution and transport of water stress at different sites on the plant is limited. In this study, water stress imposed on peanut leaves or roots by treatment with PEG 6000 is termed “leaf stress” or “root stress”, respectively. Immunoenzyme localization technolony was first used to detect ABA distribution in peanut. Under root stress, ABA biosynthesis and distribution level were all more pronounced in root than in leaf. However, ABA transport and the ability to induce stomatal closure were still better in leaf than in root during root stress; However, ABA biosynthesis initially increased in leaf, then rapidly accumulated in the vascular cambium of leaves and induced stomatal closure under leaf stress; ABA produced in root tissues was also transported to leaf tissues to maintain stomatal closure. The vascular system was involved in the coordination and integration of this complex regulatory mechanism for ABA signal accumulation. Water stress subject to root or leaf results in different of ABA biosynthesis and transport ability that trigger stoma close in peanut. PMID:27694957

  20. Dual Function of NAC072 in ABF3-Mediated ABA-Responsive Gene Regulation in Arabidopsis

    PubMed Central

    Li, Xiaoyun; Li, Xiaoling; Li, Meijuan; Yan, Youcheng; Liu, Xu; Li, Ling

    2016-01-01

    The NAM, ATAF1/2, and CUC2 (NAC) domain proteins play various roles in plant growth and stress responses. Arabidopsis NAC transcription factor NAC072 has been reported as a transcriptional activator in Abscisic acid (ABA)-responsive gene expression. However, the exact function of NAC072 in ABA signaling is still elusive. In this study, we present evidence for the interrelation between NAC072 and ABA-responsive element binding factor 3 (ABF3) that act as a positive regulator of ABA-responsive gene expression in Arabidopsis. The transcript of NAC072 is up-regulated by ABF3 in ABA response, and NAC072 protein interacts with ABF3. Enhanced ABA sensitivity occurs in nac072 mutant plants that overexpressed ABF3. However, overexpression of NAC072 weakened the ABA sensitivity in the abf3 mutant plants, but instead of recovering the ABA sensitivity of abf3. NAC072 and ABF3 cooperate to regulate RD29A expression, but are antagonistic when regulating RD29B expression. Therefore, NAC072 displays a dual function in ABF3-mediated ABA-responsive gene regulation. PMID:27486475

  1. The human gene for neurotrophic tyrosine kinase receptor type 2 (NTRK2) is located on chromosome 9 but is not the familial dysautonomia gene

    SciTech Connect

    Slaugenhaupt, S.A. |; Liebert, C.B.; Lucente, D.E.

    1995-02-10

    The neurotrophic tyrosine kinase receptor type 2 (NTRK2) gene is a member of the trk family of tyrosine protein kinases, which encode receptors for the nerve growth factor-related proteins known as neurotrophins. The neurotrophins and their receptors have long been considered candidate genes for familial dysautonomia (FD), a hereditary sensory neuropathy resulting from the congenital loss of both sensory and autonomic neurons. The DYS gene has recently been mapped to human chromosome 9q31-q33, and therefore we set out to determine the chromosomal localization of the candidate gene NTRK2. A mouse trkB probe was hybridized to both somatic cell hybrids containing human chromosome 9 and a human chromosome 9 flow-sorted cosmid library. The human homologue of trkB, NTRK2, was assigned to chromosome 9. To localize the NTRK2 gene further, a dinucleotide repeat polymorphism was identified within a cosmid that contains NTRK2 exon sequences. This marker was genotyped in the CEPH reference pedigrees and places the NTRK2 gene near D9S1 on the proximal long arm of human chromosome 9. The NTRK2 gene is located approximately 22 cm proximal to DYS and shows several recombinants in disease families. Therefore, the NTRK2 gene can now be excluded as a candidate gene for familial dysautonomia. 18 refs., 1 fig.

  2. Memantine, an NMDA receptor antagonist, differentially influences Go/No-Go performance and fMRI activity in individuals with and without a family history of alcoholism

    PubMed Central

    DeVito, E. E.; Jiantonio, R. E.; Meda, S. A.; Stevens, M. C.; Potenza, M. N.; Krystal, J. H.; Pearlson, G. D.

    2013-01-01

    Rationale Individuals with a family history of alcoholism (family history positive [FHP]) show higher alcoholism rates and are more impulsive than those without such a family history (family history negative [FHN]), possibly due to altered N-methyl-D-aspartate (NMDA) receptor function. Objectives We investigated whether memantine, an NMDA receptor antagonist, differentially influences impulsivity measures and Go/No-Go behavior and fMRI activity in matched FHP and FHN individuals. Methods On separate days, participants received a single dose of 40 mg memantine or identical-appearing placebo. Results No group performance differences were observed on placebo for Go correct hit or No-Go false alarm reaction time on the Go/No-Go task. During fMRI, right cingulate activation differed for FHP vs. FHN subjects during No-Go correct rejects. Memantine had attenuated effects in FHP vs. FHN subjects: For No-Go false alarms, memantine was associated with limited reduction in subcortical, cingulate, and temporal regions in FHP subjects and reduced activity in fronto-striatal–parietal networks in FHN subjects. For No-Go correct rejects, memantine (relative to placebo) reduced activity in left cingulate and caudate in FHP but not FHN subjects. Conclusions Lower sensitivity to the effects of memantine in FHP subjects is consistent with greater NMDA receptor function in this group. PMID:22311382

  3. A proteomic analysis of rice seed germination as affected by high temperature and ABA treatment.

    PubMed

    Liu, Shu-Jun; Xu, Heng-Heng; Wang, Wei-Qing; Li, Ni; Wang, Wei-Ping; Møller, Ian Max; Song, Song-Quan

    2015-05-01

    Seed germination is a critical phase in the plant life cycle, but the specific events associated with seed germination are still not fully understood. In this study, we used two-dimensional gel electrophoresis followed by mass spectrometry to investigate the changes in the proteome during imbibition of Oryza sativa seeds at optimal temperature with or without abscisic acid (ABA) and high temperature (germination thermoinhibition) to further identify and quantify key proteins required for seed germination. A total of 121 protein spots showed a significant change in abundance (1.5-fold increase/decrease) during germination under all conditions. Among these proteins, we found seven proteins specifically associated with seed germination including glycosyl hydrolases family 38 protein, granule-bound starch synthase 1, Os03g0842900 (putative steroleosin-B), N-carbamoylputrescine amidase, spermidine synthase 1, tubulin α-1 chain and glutelin type-A; and a total of 20 imbibition response proteins involved in energy metabolism, cell growth, cell defense and storage proteins. High temperature inhibited seed germination by decreasing the abundance of proteins involved in methionine metabolism, amino acid biosynthesis, energy metabolism, reserve degradation, protein folding and stress responses. ABA treatment inhibited germination and decreased the abundance of proteins associated with methionine metabolism, energy production and cell division. Our results show that changes in many biological processes including energy metabolism, protein synthesis and cell defense and rescue occurred as a result of all treatments, while enzymes involved in methionine metabolism and weakening of cell wall specifically accumulated when the seeds germinated at the optimal temperature.

  4. Towards the Identification of New Genes Involved in ABA-Dependent Abiotic Stresses Using Arabidopsis Suppressor Mutants of abh1 Hypersensitivity to ABA during Seed Germination

    PubMed Central

    Daszkowska-Golec, Agata; Chorazy, Edyta; Maluszynski, Miroslaw; Szarejko, Iwona

    2013-01-01

    Abscisic acid plays a pivotal role in the abiotic stress response in plants. Although great progress has been achieved explaining the complexity of the stress and ABA signaling cascade, there are still many questions to answer. Mutants are a valuable tool in the identification of new genes or new alleles of already known genes and in elucidating their role in signaling pathways. We applied a suppressor mutation approach in order to find new components of ABA and abiotic stress signaling in Arabidopsis. Using the abh1 (ABA hypersensitive 1) insertional mutant as a parental line for EMS mutagenesis, we selected several mutants with suppressed hypersensitivity to ABA during seed germination. Here, we present the response to ABA and a wide range of abiotic stresses during the seed germination and young seedling development of two suppressor mutants—soa2 (suppressor of abh1 hypersensitivity to ABA 2) and soa3 (suppressor of abh1 hypersensitivity to ABA 3). Generally, both mutants displayed a suppression of the hypersensitivity of abh1 to ABA, NaCl and mannitol during germination. Both mutants showed a higher level of tolerance than Columbia-0 (Col-0—the parental line of abh1) in high concentrations of glucose. Additionally, soa2 exhibited better root growth than Col-0 in the presence of high ABA concentrations. soa2 and soa3 were drought tolerant and both had about 50% fewer stomata per mm2 than the wild-type but the same number as their parental line—abh1. Taking into account that suppressor mutants had the same genetic background as their parental line—abh1, it was necessary to backcross abh1 with Landsberg erecta four times for the map-based cloning approach. Mapping populations, derived from the cross of abh1 in the Landsberg erecta background with each suppressor mutant, were created. Map based cloning in order to identify the suppressor genes is in progress. PMID:23807502

  5. Intermittent hypoxia induces the proliferation of rat vascular smooth muscle cell with the increases in epidermal growth factor family and erbB2 receptor

    SciTech Connect

    Kyotani, Yoji; Ota, Hiroyo; Itaya-Hironaka, Asako; Yamauchi, Akiyo; Sakuramoto-Tsuchida, Sumiyo; Zhao, Jing; Ozawa, Kentaro; Nagayama, Kosuke; Ito, Satoyasu; Takasawa, Shin; Kimura, Hiroshi; Uno, Masayuki; Yoshizumi, Masanori

    2013-11-15

    Obstructive sleep apnea is characterized by intermittent hypoxia (IH), and associated with cardiovascular diseases, such as stroke and heart failure. These cardiovascular diseases have a relation to atherosclerosis marked by the proliferation of vascular smooth muscle cells (VSMCs). In this study, we investigated the influence of IH on cultured rat aortic smooth muscle cell (RASMC). The proliferation of RASMC was significantly increased by IH without changing the level of apoptosis. In order to see what induces RASMC proliferation, we investigated the influence of normoxia (N)-, IH- and sustained hypoxia (SH)-treated cell conditioned media on RASMC proliferation. IH-treated cell conditioned medium significantly increased RASMC proliferation compared with N-treated cell conditioned medium, but SH-treated cell conditioned medium did not. We next investigated the epidermal growth factor (EGF) family as autocrine growth factors. Among the EGF family, we found significant increases in mRNAs for epiregulin (ER), amphiregulin (AR) and neuregulin-1 (NRG1) in IH-treated cells and mature ER in IH-treated cell conditioned medium. We next investigated the changes in erbB family receptors that are receptors for ER, AR and NRG1, and found that erbB2 receptor mRNA and protein expressions were increased by IH, but not by SH. Phosphorylation of erbB2 receptor at Tyr-1248 that mediates intracellular signaling for several physiological effects including cell proliferation was increased by IH, but not by SH. In addition, inhibitor for erbB2 receptor suppressed IH-induced cell proliferation. These results provide the first demonstration that IH induces VSMC proliferation, and suggest that EGF family, such as ER, AR and NRG1, and erbB2 receptor could be involved in the IH-induced VSMC proliferation. - Highlights: ●In vitro system for intermittent hypoxia (IH) and sustained hypoxia (SH). ●IH, but not SH, induces the proliferation of rat vascular smooth muscle cell. ●Epiregulin m

  6. Environmental signals generate a differential and coordinated expression of the heme receptor gene family of Bartonella quintana.

    PubMed

    Battisti, James M; Sappington, Kate N; Smitherman, Laura S; Parrow, Nermi L; Minnick, Michael F

    2006-06-01

    Of all bacteria, Bartonella quintana has the highest reported in vitro hemin requirement, yet an explanation for this remains elusive. To produce diseases such as trench fever, endocarditis, and bacillary angiomatosis, B. quintana must survive and replicate in the disparate environments of the Pediculus humanus corporis (body louse) gut and the human vasculature. We previously identified a five-member family of hemin binding proteins (Hbps) synthesized by B. quintana that bind hemin on the outer surface but share no similarity to known bacterial heme receptors. In the present study, we examine the transcription, regulation, and synthesis of this virulence factor family by cultivation of the bacterium in environments that simulate natural heme, oxygen, and temperature conditions encountered in the host and insect vector. First, quantitative real-time PCR data show that hbpC expression is regulated by temperature, where a >100-fold increase in transcript quantity was seen at 30 degrees C relative to 37 degrees C, suggesting that HbpC synthesis would be greatest in the cooler temperature of the louse. Second, cultivation at human bloodstream oxygen concentration (5% relative to 21% atmospheric) significantly decreases the transcript quantity of all hbp genes, indicating that expression is influenced by O2 and/or reactive oxygen species. Third, a differential expression pattern within the hbp family is revealed when B. quintana is grown in a range of hemin concentrations: subgroup I (hbpC and hbpB) predominates in a simulated louse environment (high heme), and subgroup II (hbpA, hbpD, and hbpE) is preferentially expressed in a simulated human background (low heme). By using two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and matrix-assisted laser desorption ionization-time of flight mass spectrometry fingerprinting, we demonstrate that synthesis of HbpA correlates with hbpA transcript increases observed at low hemin

  7. Genetic variation in the odorant receptors family 13 and the mhc loci influence mate selection in a multiple sclerosis dataset

    PubMed Central

    2010-01-01

    Background When selecting mates, many vertebrate species seek partners with major histocompatibility complex (MHC) genes different from their own, presumably in response to selective pressure against inbreeding and towards MHC diversity. Attempts at replication of these genetic results in human studies, however, have reached conflicting conclusions. Results Using a multi-analytical strategy, we report validated genome-wide relationships between genetic identity and human mate choice in 930 couples of European ancestry. We found significant similarity between spouses in the MHC at class I region in chromosome 6p21, and at the odorant receptor family 13 locus in chromosome 9. Conversely, there was significant dissimilarity in the MHC class II region, near the HLA-DQA1 and -DQB1 genes. We also found that genomic regions with significant similarity between spouses show excessive homozygosity in the general population (assessed in the HapMap CEU dataset). Conversely, loci that were significantly dissimilar among spouses were more likely to show excessive heterozygosity in the general population. Conclusions This study highlights complex patterns of genomic identity among partners in unrelated couples, consistent with a multi-faceted role for genetic factors in mate choice behavior in human populations. PMID:21067613

  8. The use of low density lipoprotein receptor activity of lymphocytes to determine the prevalence of familial hypercholesterolaemia in a rural South African community.

    PubMed Central

    Steyn, K; Weight, M J; Dando, B R; Christopher, K J; Rossouw, J E

    1989-01-01

    The diagnosis of heterozygous familial hypercholesterolaemia in three rural South African communities in which hypercholesterolaemia is very prevalent could be confirmed by the measurement of low density lipoprotein (LDL) receptor activity in circulating lymphocytes. A nominal cut off point could be proposed which separated the LDL receptor activity of 24 clinically diagnosed heterozygous FH patients and 31 healthy people. LDL receptor activity was measured as total degradation of 125I-LDL and expressed as ng LDL/mg cell protein/6 hours. The cut off point was set at 970 ng/mg protein/6 hours. This proposed cut off point was tested by assaying the LDL receptor of three homozygous FH patients and seven of their obligate heterozygous FH first degree relatives. The three homozygous FH patients showed no receptor activity and the activity of the seven obligate heterozygous first degree relatives fell below the proposed cut off point. To determine the prevalence of FH in the study population, all persons aged 15 to 24 years whose total cholesterol levels fell above the 80th centile for their age and sex, as well as their families, were approached (n = 114). The LDL receptor activity in lymphocytes of 77 of these persons aged 15 to 24 years was determined after applying the exclusion criteria. Ten of the 77 participants had LDL receptor activity below 970 ng LDL/mg protein/6 hours and were therefore diagnosed as being heterozygous FH patients. The calculation of the prevalence (corrected for exclusions) revealed that one in 71 of the 15 to 24 year old permanent residents in the predominantly Afrikaans speaking community suffered from heterozygous FH. This is higher than any FH prevalence previously reported for any group. PMID:2918524

  9. The Receptor Kinase IMPAIRED OOMYCETE SUSCEPTIBILITY1 Attenuates Abscisic Acid Responses in Arabidopsis1[C][W

    PubMed Central

    Hok, Sophie; Allasia, Valérie; Andrio, Emilie; Naessens, Elodie; Ribes, Elsa; Panabières, Franck; Attard, Agnès; Ris, Nicolas; Clément, Mathilde; Barlet, Xavier; Marco, Yves; Grill, Erwin; Eichmann, Ruth; Weis, Corina; Hückelhoven, Ralph; Ammon, Alexandra; Ludwig-Müller, Jutta; Voll, Lars M.; Keller, Harald

    2014-01-01

    In plants, membrane-bound receptor kinases are essential for developmental processes, immune responses to pathogens and the establishment of symbiosis. We previously identified the Arabidopsis (Arabidopsis thaliana) receptor kinase IMPAIRED OOMYCETE SUSCEPTIBILITY1 (IOS1) as required for successful infection with the downy mildew pathogen Hyaloperonospora arabidopsidis. We report here that IOS1 is also required for full susceptibility of Arabidopsis to unrelated (hemi)biotrophic filamentous oomycete and fungal pathogens. Impaired susceptibility in the absence of IOS1 appeared to be independent of plant defense mechanism. Instead, we found that ios1-1 plants were hypersensitive to the plant hormone abscisic acid (ABA), displaying enhanced ABA-mediated inhibition of seed germination, root elongation, and stomatal opening. These findings suggest that IOS1 negatively regulates ABA signaling in Arabidopsis. The expression of ABA-sensitive COLD REGULATED and RESISTANCE TO DESICCATION genes was diminished in Arabidopsis during infection. This effect on ABA signaling was alleviated in the ios1-1 mutant background. Accordingly, ABA-insensitive and ABA-hypersensitive mutants were more susceptible and resistant to oomycete infection, respectively, showing that the intensity of ABA signaling affects the outcome of downy mildew disease. Taken together, our findings suggest that filamentous (hemi)biotrophs attenuate ABA signaling in Arabidopsis during the infection process and that IOS1 participates in this pathogen-mediated reprogramming of the host. PMID:25274985

  10. Investigation of the Dimerization of Proteins from the Epidermal Growth Factor Receptor Family by Single Wavelength Fluorescence Cross-Correlation Spectroscopy

    PubMed Central

    Liu, Ping; Sudhaharan, Thankiah; Koh, Rosita M. L.; Hwang, Ling C.; Ahmed, Sohail; Maruyama, Ichiro N.; Wohland, Thorsten

    2007-01-01

    Single wavelength fluorescence cross-correlation spectroscopy (SW-FCCS), introduced to study biomolecular interactions, has recently been reported to monitor enzyme activity by using a newly developed fluorescent protein variant together with cyan fluorescent protein. Here, for the first time to our knowledge, SW-FCCS is applied to detect interactions between membrane receptors in vivo by using the widely used enhanced green fluorescent protein and monomeric red fluorescent protein. The biological system studied here is the epidermal growth factor/ErbB receptor family, which plays pivotal roles in the development of organisms ranging from worms to humans. It is widely thought that a ligand binds to the monomeric form of the receptor and induces its dimeric form for activation. By using SW-FCCS and Förster resonance energy transfer, we show that the epidermal growth factor receptor and ErbB2 have preformed homo- and heterodimeric structures on the cell surface and quantitation of dimer fractions is performed by SW-FCCS. These receptors are major targets of anti-cancer drug development, and the receptors' homo- and heterodimeric structures are relevant for such developments. PMID:17468161

  11. Microemulsions of ABA Amphiphilic Block Copolymers and Surfactants

    NASA Astrophysics Data System (ADS)

    Braun-Shmueli, Liora; Netanel, Ortal; Regev, Oren; Gottlieb, Moshe

    2001-03-01

    The system composed of oil (decane), water and an ABA amphiphilic block copolymer is capable of exhibiting an extremely rich phase and rheological behavior. In this paper we describe the rheological properties of a synthetic amphiphilic block copolymer dissolved in a water-in-oil microemulsion with and without the stabilizing effect of small molecular weight surfactant molecules. The block copolymer is an ABA type copolymer composed of poly(oxyethylene) (PEO) as the hydrophilic A block and poly(dimethyl siloxane) (PDMS) as the hydrophobic center B block. The resulting copolymer is insoluble in water and hardly soluble in decane (good solvent for the PDMS). In the presence of water in oil microemulsion stabilized by the small molecular weight surfactant AOT a one-phase region is maintained when the copolymer is added. Yet, peculiar rheological behavior is observed. For constant water-microemulsion concentration (φ) addition of polymer increases the system viscosity as expected. Yet, the lower φ the higher the viscosity and at high φ the effect of polymer addition is quite low. Furthermore, the insoluble block copolymer in oil turns into a gel-like one phase system upon addition of small amounts of either water or water and surfactant solution. Experiments show that a maximum in elasticity or viscosity is attained at a droplet concentration equivalent to about 80 polymer chains per drop. Small angle x-ray and neutron scattering experiments were carried out to elucidate the system morphology.

  12. The importance of molecular profiling in predicting response to epidermal growth factor receptor family inhibitors in non-small-cell lung cancer: focus on clinical trial results.

    PubMed

    Tsao, Anne S; Papadimitrakopoulou, Vassiliki

    2013-07-01

    In recent years, the epidermal growth factor receptor (EGFR) family has become a key focus of non-small-cell lung cancer biology and targeted therapies, such as the reversible EGFR tyrosine kinase inhibitors erlotinib and gefitinib. Initially, response to these agents was associated with certain demographic and clinical characteristics; subsequently, it was discovered that these subgroups were more likely to harbor specific mutations in the EGFR gene that enhanced tumor response. However, the presence of these mutations does not equate to therapeutic success. Other aspects of EGFR family signaling, including other types of EGFR mutations, EGFR protein expression, EGFR gene amplification, mediators of downstream signaling, and other receptors with similar downstream pathways may all play a role in response or resistance to treatment. The identification of these and other molecular determinants is driving the development of novel therapies designed to achieve improved clinical outcomes in patients.

  13. CD137, a member of the tumor necrosis factor receptor family, is located on chromosome 1p36, in a cluster of related genes, and colocalizes with several malignancies.

    PubMed

    Schwarz, H; Arden, K; Lotz, M

    1997-06-27

    CD137 (ILA/4-1BB) is a member of the tumor-necrosis-factor receptor family. Members of this receptor family and their structurally related ligands are important regulators of a wide variety of physiological processes and play an especially important role in the regulation of immune responses. CD137 regulates cell proliferation and survival of T-lymphocytes. Using Southern blot analysis and polymerase chain reaction, we localized the CD137 gene to chromosome 1p36. This chromosomal region harbors the genes of several other members of this receptor family and is associated with deletions and rearrangements in several malignancies.

  14. Mutations of the AMH type II receptor in two extended families with persistent Müllerian duct syndrome: lack of phenotype/genotype correlation.

    PubMed

    Abduljabbar, Mohammad; Taheini, Khalid; Picard, Jean-Yves; Cate, Richard L; Josso, Nathalie

    2012-01-01

    Our goal was to compare phenotype and genotype in two extended Middle-Eastern families affected by persistent Müllerian duct syndrome due to mutations of the type II anti-Müllerian hormone receptor (AMHR-II). The first, consanguineous, family consisted of 6 boys and 2 girls, the second consisted of 4 girls and 2 boys. In family I, 4 boys and 1 girl were homozygous for a stop mutation in the 9th exon of AMHR-II, removing part of the intracellular domain of the protein. In family II, 1 girl and 1 boy were homozygous for a transversion changing conserved histidine 254 into a glutamine. Both homozygous girls were normal. In the homozygous males, the degree of development of Müllerian derivatives was variable. The uterus was well developed in 2 boys of family I and in the patient from family II; however, in 1 subject from family I, Müllerian derivatives were undetectable. Taken together, the diversity of clinical symptoms within the same sibship and the lack of correlation between the development of the Müllerian derivatives and the severity of the molecular defects suggest highly variable penetrance of the abnormal alleles and/or the existence of other genetic or epigenetic modifiers of gene expression. PMID:22584735

  15. Mammalian α arrestins link activated seven transmembrane receptors to Nedd4 family e3 ubiquitin ligases and interact with β arrestins.

    PubMed

    Shea, Fortune F; Rowell, Jennie L; Li, Yechaowei; Chang, Tien-Hsien; Alvarez, Carlos E

    2012-01-01

    The complement of fungal cell surface proteins is widely regulated by ubiquitination of membrane proteins, which results in their endocytosis and vacuolar degradation. For diverse fungal transporters, the specificity of ubiquitination is conferred by alpha arrestin adaptors, which recruit the Nedd4 family E3 ubiquitin ligase Rsp5. A recent study showed that one mammalian alpha arrestin also mediates ubiquitination and lysosomal trafficking of an activated plasma membrane receptor. Here we first screen all five widely-expressed human alpha arrestins for subcellular localization in ligand-stimulated and -unstimulated cells overexpressing the seven transmembrane receptor vasopressin 2. We then characterize the effects of alpha arrestins ARRDC3 and ARRDC4 upon activation of the seven transmembrane receptors vasopressin 2 and beta adrenergic 2. Using biochemical and imaging approaches, we show that ligand-activated receptors interact with alpha arrestins, and this results in recruitment of Nedd4 family E3 ubiquitin ligases and receptor ubiquitination - which are known to result in lysosomal trafficking. Our time course studies show these effects occur in the first 1-5 minutes after ligand activation, the same time that beta arrestins are known to have roles in receptor endocytic trafficking and kinase signaling. We tested the possibility that alpha and beta arrestins function coordinately and found co-immunoprecipitation and colocalization evidence to support this. Others recently reported that Arrdc3 knockout mice are lean and resistant to obesity. In the course of breeding our own Arrdc3-deficient mice, we observed two novel phenotypes in homozygotes: skin abnormalities, and embryonic lethality on normal chow diet, but not on high fat diet. Our findings suggest that alpha and beta arrestins function coordinately to maintain the optimal complement and function of cell surface proteins according to cellular physiological context and external signals. We discuss the

  16. Overexpression of an ABA biosynthesis gene using a stress inducible promoter enhances drought resistance in petunia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants respond to drought stress by closing their stomata and reducing transpirational water loss. The plant hormone abscisic acid (ABA) regulates growth and stomatal closure particularly when the plant is under environmental stresses. One of the key enzymes in the ABA biosynthesis of higher plants ...

  17. The effects of abscisic acid (ABA) addition on cadmium accumulation of two ecotypes of Solanum photeinocarpum.

    PubMed

    Wang, Jin; Lin, Lijin; Luo, Li; Liao, Ming'an; Lv, Xiulan; Wang, Zhihui; Liang, Dong; Xia, Hui; Wang, Xun; Lai, Yunsong; Tang, Yi

    2016-03-01

    The study of the effects of exogenous abscisic acid (ABA) addition on cadmium (Cd) accumulation of two ecotypes (mining and farmland) of Solanum photeinocarpum was operated through a pot experiment. The results showed that the biomass and chlorophyll content of the two ecotypes of S. photeinocarpum increased with increasing ABA concentration. Applying exogenous ABA increased Cd content in the two ecotypes of S. photeinocarpum. The maximum Cd contents in shoots of the two ecotypes of S. photeinocarpum were obtained at 20 μmol/L ABA; shoot Cd contents respectively for the mining and farmland ecotypes were 33.92 and 24.71% higher than those for the control. Applying exogenous ABA also increased Cd extraction by the two ecotypes of S. photeinocarpum, and the highest Cd extraction was obtained at 20 μmol/L ABA with 569.42 μg/plant in shoots of the mining ecotype and 520.51 μg/plant in shoots of the farmland ecotype respectively. Therefore, exogenous ABA can be used for enhancing the Cd extraction ability of S. photeinocarpum, and 20 μmol/L ABA was the optimal dose. PMID:26899030

  18. ABA in bryophytes: how a universal growth regulator in life became a plant hormone?

    PubMed

    Takezawa, Daisuke; Komatsu, Kenji; Sakata, Yoichi

    2011-07-01

    Abscisic acid (ABA) is not a plant-specific compound but one found in organisms across kingdoms from bacteria to animals, suggesting that it is a ubiquitous and versatile substance that can modulate physiological functions of various organisms. Recent studies have shown that plants developed an elegant system for ABA sensing and early signal transduction mechanisms to modulate responses to environmental stresses for survival in terrestrial conditions. ABA-induced increase in stress tolerance has been reported not only in vascular plants but also in non-vascular bryophytes. Since bryophytes are the key group of organisms in the context of plant evolution, clarification of their ABA-dependent processes is important for understanding evolutionary adaptation of land plants. Molecular approaches using Physcomitrella patens have revealed that ABA plays a role in dehydration stress tolerance in mosses, which comprise a major group of bryophytes. Furthermore, we recently reported that signaling machinery for ABA responses is also conserved in liverworts, representing the most basal members of extant land plant lineage. Conservation of the mechanism for ABA sensing and responses in angiosperms and basal land plants suggests that acquisition of this mechanism for stress tolerance in vegetative tissues was one of the critical evolutionary events for adaptation to the land. This review describes the role of ABA in basal land plants as well as non-land plant organisms and further elaborates on recent progress in molecular studies of model bryophytes by comparative and functional genomic approaches.

  19. Involvement of plant endogenous ABA in Bacillus megaterium PGPR activity in tomato plants

    PubMed Central

    2014-01-01

    Background Plant growth-promoting rhizobacteria (PGPR) are naturally occurring soil bacteria which benefit plants by improving plant productivity and immunity. The mechanisms involved in these processes include the regulation of plant hormone levels such as ethylene and abscisic acid (ABA). The aim of the present study was to determine whether the activity of Bacillus megaterium PGPR is affected by the endogenous ABA content of the host plant. The ABA-deficient tomato mutants flacca and sitiens and their near-isogenic wild-type parental lines were used. Growth, stomatal conductance, shoot hormone concentration, competition assay for colonization of tomato root tips, and root expression of plant genes expected to be modulated by ABA and PGPR were examined. Results Contrary to the wild-type plants in which PGPR stimulated growth rates, PGPR caused growth inhibition in ABA-deficient mutant plants. PGPR also triggered an over accumulation of ethylene in ABA-deficient plants which correlated with a higher expression of the pathogenesis-related gene Sl-PR1b. Conclusions Positive correlation between over-accumulation of ethylene and a higher expression of Sl-PR1b in ABA-deficient mutant plants could indicate that maintenance of normal plant endogenous ABA content may be essential for the growth promoting action of B. megaterium by keeping low levels of ethylene production. PMID:24460926

  20. The effects of abscisic acid (ABA) addition on cadmium accumulation of two ecotypes of Solanum photeinocarpum.

    PubMed

    Wang, Jin; Lin, Lijin; Luo, Li; Liao, Ming'an; Lv, Xiulan; Wang, Zhihui; Liang, Dong; Xia, Hui; Wang, Xun; Lai, Yunsong; Tang, Yi

    2016-03-01

    The study of the effects of exogenous abscisic acid (ABA) addition on cadmium (Cd) accumulation of two ecotypes (mining and farmland) of Solanum photeinocarpum was operated through a pot experiment. The results showed that the biomass and chlorophyll content of the two ecotypes of S. photeinocarpum increased with increasing ABA concentration. Applying exogenous ABA increased Cd content in the two ecotypes of S. photeinocarpum. The maximum Cd contents in shoots of the two ecotypes of S. photeinocarpum were obtained at 20 μmol/L ABA; shoot Cd contents respectively for the mining and farmland ecotypes were 33.92 and 24.71% higher than those for the control. Applying exogenous ABA also increased Cd extraction by the two ecotypes of S. photeinocarpum, and the highest Cd extraction was obtained at 20 μmol/L ABA with 569.42 μg/plant in shoots of the mining ecotype and 520.51 μg/plant in shoots of the farmland ecotype respectively. Therefore, exogenous ABA can be used for enhancing the Cd extraction ability of S. photeinocarpum, and 20 μmol/L ABA was the optimal dose.

  1. ABA-Regulation of Two Classes of Embryo-Specific Sequences in Mature Wheat Embryos 1

    PubMed Central

    Williamson, John D.; Quatrano, Ralph S.

    1988-01-01

    We have previously described the isolation and characterization of ABA-enhanced sequences from developing wheat embryos. Here we use in vivo RNA labeling and the inhibitors α-amanitin and cycloheximide to determine the level at which ABA acts to modulate these sequences in cultured mature embryos. Sequences fell into two classes: one, represented by the 7S globulin clone, p511, appears to be regulated at the level of transcription, while the other, represented by the early methionine-labeled polypeptide (Em)-protein clone, p1015, has an additional posttranscriptional component. In mature embryos cultured in the absence of ABA, mRNA levels of p511 and p1015 declined rapidly until neither was detected at 3 days postimbibition. Levels of p511 increased in mature embryos cultured in the presence of ABA, but remained low in the presence of ABA + α-amanitin, suggesting p511 RNA is regulated at the level of transcription. Levels of p1015, in contrast, remained high not only in the presence of ABA, but also in the presence of ABA + α-amanitin or α-amanitin alone. This suggests p1015 regulation might be at the level of selective RNA stability. Cycloheximide had no detectable effect on ABA-mediated stabilization of p1015, suggesting that newly synthesized proteins are not involved. Em-protein synthesis rates closely paralleled Em RNA levels, suggesting Em expression is not controlled at the level of translation. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:16665868

  2. Lipoprotein-mediated lipid transport in insects: analogy to the mammalian lipid carrier system and novel concepts for the functioning of LDL receptor family members.

    PubMed

    Rodenburg, Kees W; Van der Horst, Dick J

    2005-09-01

    In all animals, lipoproteins are used to transport lipids through the aqueous circulation. Lipids are delivered to mammalian cells by two different mechanisms: via endocytic uptake of the complete lipoprotein particle mediated by members of the low density lipoprotein (LDL) receptor (LDLR) family, or by selective delivery of lipoprotein-carried lipids at the cell surface, such as lipid uptake following the action of a lipoprotein lipase. Although many structural elements of the lipid transport system of insects are similar to those of mammals, insect lipoprotein-mediated lipid transport was thought to apply only to the latter concept, since the single lipoprotein acts as a reusable lipid shuttle. However, the recent identification of lipoprotein receptors of the LDLR family in insects suggests that lipid transport in these animals may also adopt the first concept. Yet, the endocytic properties of the insect LDLR homologue appear to deviate from those of the mammalian LDLR family members, resulting in the recycling of endocytosed lipoprotein in a transferrin-like manner. This indicates that a hitherto unknown as well as unexpected function can be added to the plethora of functions of LDLR family members. Analysis of the molecular mechanism of the ligand-recycling function of the insect receptor provides also new insight into the possible functioning of the mammalian family members. In the last several years, mammalian and insect lipoprotein-mediated lipid transport systems have been reviewed separately with respect to functioning and lipid delivery. This review, in which new and important developments in the insect field with respect to our understanding of lipid delivery are discussed with a particular focus on the involvement of the LDLR homologue, aims at comparing the two systems, also from an evolutionary biological perspective, and proposes that the two systems are more similar than assumed previously. PMID:16099208

  3. Biodistribution of AAV8 Vectors Expressing Human Low-Density Lipoprotein Receptor in a Mouse Model of Homozygous Familial Hypercholesterolemia

    PubMed Central

    Chen, Shu-Jen; Sanmiguel, Julio; Lock, Martin; McMenamin, Deirdre; Draper, Christine; Limberis, Maria P.; Kassim, Sadik H.; Somanathan, Suryanarayan; Bell, Peter; Johnston, Julie C.; Rader, Daniel J.

    2013-01-01

    Abstract Recombinant adeno-associated viral vectors based on serotype 8 (AAV8) transduce liver with superior tropism following intravenous (IV) administration. Previous studies conducted by our lab demonstrated that AAV8-mediated transfer of the human low-density lipoprotein receptor (LDLR) gene driven by a strong liver-specific promoter (thyroxin-binding globulin [TBG]) leads to high level and persistent gene expression in the liver. The approach proved efficacious in reducing plasma cholesterol levels and resulted in the regression of atherosclerotic lesions in a murine model of homozygous familial hypercholesterolemia (hoFH). Prior to advancing this vector, called AAV8.TBG.hLDLR, to the clinic, we set out to investigate vector biodistribution in an hoFH mouse model following IV vector administration to assess the safety profile of this investigational agent. Although AAV genomes were present in all organs at all time points tested (up to 180 days), vector genomes were sequestered mainly in the liver, which contained levels of vector 3 logs higher than that found in other organs. In both sexes, the level of AAV genomes gradually declined and appeared to stabilize 90 days post vector administration in most organs although vector genomes remained high in liver. Vector loads in the circulating blood were high and close to those in liver at the early time point (day 3) but rapidly decreased to a level close to the limit of quantification of the assay. The results of this vector biodistribution study further support a proposed clinical trial to evaluate AAV8 gene therapy for hoFH patients. PMID:24070336

  4. Biodistribution of AAV8 vectors expressing human low-density lipoprotein receptor in a mouse model of homozygous familial hypercholesterolemia.

    PubMed

    Chen, Shu-Jen; Sanmiguel, Julio; Lock, Martin; McMenamin, Deirdre; Draper, Christine; Limberis, Maria P; Kassim, Sadik H; Somanathan, Suryanarayan; Bell, Peter; Johnston, Julie C; Rader, Daniel J; Wilson, James M

    2013-12-01

    Recombinant adeno-associated viral vectors based on serotype 8 (AAV8) transduce liver with superior tropism following intravenous (IV) administration. Previous studies conducted by our lab demonstrated that AAV8-mediated transfer of the human low-density lipoprotein receptor (LDLR) gene driven by a strong liver-specific promoter (thyroxin-binding globulin [TBG]) leads to high level and persistent gene expression in the liver. The approach proved efficacious in reducing plasma cholesterol levels and resulted in the regression of atherosclerotic lesions in a murine model of homozygous familial hypercholesterolemia (hoFH). Prior to advancing this vector, called AAV8.TBG.hLDLR, to the clinic, we set out to investigate vector biodistribution in an hoFH mouse model following IV vector administration to assess the safety profile of this investigational agent. Although AAV genomes were present in all organs at all time points tested (up to 180 days), vector genomes were sequestered mainly in the liver, which contained levels of vector 3 logs higher than that found in other organs. In both sexes, the level of AAV genomes gradually declined and appeared to stabilize 90 days post vector administration in most organs although vector genomes remained high in liver. Vector loads in the circulating blood were high and close to those in liver at the early time point (day 3) but rapidly decreased to a level close to the limit of quantification of the assay. The results of this vector biodistribution study further support a proposed clinical trial to evaluate AAV8 gene therapy for hoFH patients. PMID:24070336

  5. Physiological impacts of ABA-JA interactions under water-limitation.

    PubMed

    de Ollas, Carlos; Dodd, Ian C

    2016-08-01

    Plant responses to drought stress depend on highly regulated signal transduction pathways with multiple interactions. This complex crosstalk can lead to a physiological outcome of drought avoidance or tolerance/resistance. ABA is the principal mediator of these responses due to the regulation of stomatal closure that determines plant growth and survival, but also other strategies of drought resistance such as osmotic adjustment. However, other hormones such as JA seem responsible for regulating a subset of plant responses to drought by regulating ABA biosynthesis and accumulation and ABA-dependent signalling, but also by ABA independent pathways. Here, we review recent reports of ABA-JA hormonal and molecular interactions within a physiological framework of drought tolerance. Understanding the physiological significance of this complex regulation offers opportunities to find strategies of drought tolerance that avoid unwanted side effects that limit growth and yield, and may allow biotechnological crop improvement. PMID:27299601

  6. Physiological impacts of ABA-JA interactions under water-limitation.

    PubMed

    de Ollas, Carlos; Dodd, Ian C

    2016-08-01

    Plant responses to drought stress depend on highly regulated signal transduction pathways with multiple interactions. This complex crosstalk can lead to a physiological outcome of drought avoidance or tolerance/resistance. ABA is the principal mediator of these responses due to the regulation of stomatal closure that determines plant growth and survival, but also other strategies of drought resistance such as osmotic adjustment. However, other hormones such as JA seem responsible for regulating a subset of plant responses to drought by regulating ABA biosynthesis and accumulation and ABA-dependent signalling, but also by ABA independent pathways. Here, we review recent reports of ABA-JA hormonal and molecular interactions within a physiological framework of drought tolerance. Understanding the physiological significance of this complex regulation offers opportunities to find strategies of drought tolerance that avoid unwanted side effects that limit growth and yield, and may allow biotechnological crop improvement.

  7. The Role of MAPK Modules and ABA during Abiotic Stress Signaling.

    PubMed

    de Zelicourt, Axel; Colcombet, Jean; Hirt, Heribert

    2016-08-01

    To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses in plants, triggering major changes in plant physiology. The ABA core signaling pathway largely relies on the activation of SnRK2 kinases to mediate several rapid responses, including gene regulation, stomatal closure, and plant growth modulation. Mitogen-activated protein kinases (MAPKs) have also been implicated in ABA signaling, but an entire ABA-activated MAPK module was uncovered only recently. In this review, we discuss the evidence for a role of MAPK modules in the context of different plant ABA signaling pathways. PMID:27143288

  8. Unravelling the Evolution of the Allatostatin-Type A, KISS and Galanin Peptide-Receptor Gene Families in Bilaterians: Insights from Anopheles Mosquitoes

    PubMed Central

    Felix, Rute C.; Trindade, Marlene; Pires, Isa R. P.; Fonseca, Vera G.; Martins, Rute S.; Silveira, Henrique; Power, Deborah M.; Cardoso, João C. R.

    2015-01-01

    Allatostatin type A receptors (AST-ARs) are a group of G-protein coupled receptors activated by members of the FGL-amide (AST-A) peptide family that inhibit food intake and development in arthropods. Despite their physiological importance the evolution of the AST-A system is poorly described and relatively few receptors have been isolated and functionally characterised in insects. The present study provides a comprehensive analysis of the origin and comparative evolution of the AST-A system. To determine how evolution and feeding modified the function of AST-AR the duplicate receptors in Anopheles mosquitoes, were characterised. Phylogeny and gene synteny suggested that invertebrate AST-A receptors and peptide genes shared a common evolutionary origin with KISS/GAL receptors and ligands. AST-ARs and KISSR emerged from a common gene ancestor after the divergence of GALRs in the bilaterian genome. In arthropods, the AST-A system evolved through lineage-specific events and the maintenance of two receptors in the flies and mosquitoes (Diptera) was the result of a gene duplication event. Speciation of Anopheles mosquitoes affected receptor gene organisation and characterisation of AST-AR duplicates (GPRALS1 and 2) revealed that in common with other insects, the mosquito receptors were activated by insect AST-A peptides and the iCa2+-signalling pathway was stimulated. GPRALS1 and 2 were expressed mainly in mosquito midgut and ovaries and transcript abundance of both receptors was modified by feeding. A blood meal strongly up-regulated expression of both GPRALS in the midgut (p < 0.05) compared to glucose fed females. Based on the results we hypothesise that the AST-A system in insects shared a common origin with the vertebrate KISS system and may also share a common function as an integrator of metabolism and reproduction. Highlights: AST-A and KISS/GAL receptors and ligands shared common ancestry prior to the protostome-deuterostome divergence. Phylogeny and gene

  9. Association of advanced glycation end products with A549 cells, a human pulmonary epithelial cell line, is mediated by a receptor distinct from the scavenger receptor family and RAGE.

    PubMed

    Nakano, Nahoko; Fukuhara-Takaki, Kaori; Jono, Tadashi; Nakajou, Keisuke; Eto, Nobuaki; Horiuchi, Seikoh; Takeya, Motohiro; Nagai, Ryoji

    2006-05-01

    Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE.

  10. Expansion of the. alpha. sub 2 -adrenergic receptor family: Cloning and characterization of a human. alpha. sub 2 -adrenergic receptor subtype, the gene for which is located on chromosome 2

    SciTech Connect

    Lomasney, J.W.; Lorenz, W.; Allen, L.F.; King, K.; Caron, M.G.; Lefkowitz, R.J. ); Regan, J.W. ); Yang-Feng, T.L. )

    1990-07-01

    Pharmacologic, biochemical, and genetic analyses have demonstrated the existence of multiple {alpha}{sub 2}-adrenergic receptor ({alpha}{sub 2}AR) subtypes. The authors have cloned a human {alpha}{sub 2}AR by using the polymerase chain reaction with oligonucleotide primers homologous to conserved regions of the previously cloned {alpha}{sub 2}ARs, the genes for which are located on human chromosomes 4 (C4) and 10 (C10). The deduced amino acid sequence encodes a protein of 450 amino acids whose putative topology is similar to that of the family of guanine nucleotide-binding protein-coupled receptors, but whose structure most closely resembles that of the {alpha}{sub 2}ARs. Competition curve analysis of the binding properties of the receptor expressed in COS-7 cells with a variety of adrenergic ligands demonstrates a unique {alpha}{sub 2}AR pharmacology. Hybridization with somatic cell hybrids shows that the gene for this receptor is located on chromosome 2. Northern blot analysis of various rat tissues shows expression in liver and kidney. The unique pharmacology and tissue localization of this receptor suggest that this is an {alpha}{sub 2}AR subtype not previously identified by classical pharmacological or ligand binding approaches.

  11. The role of ABA in triggering ethylene biosynthesis and ripening of tomato fruit

    PubMed Central

    Zhang, Mei; Yuan, Bing; Leng, Ping

    2009-01-01

    In order to understand more details about the role of abscisic acid (ABA) in fruit ripening and senescence of tomato, two cDNAs (LeNCED1 and LeNCED2) which encode 9-cis-epoxycarotenoid dioxygenase (NCED) as a key enzyme in ABA biosynthesis, two cDNAs (LeACS2 and LeACS4) which encode 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, and one cDNA (LeACO1) which encodes ACC oxidase involved in ethylene biosynthesis were cloned from tomato fruit using a reverse transcription-PCR (RT-PCR) approach. The relationship between ABA and ethylene during ripening was also investigated. Among six sampling times in tomato fruits, the LeNCED1 gene was highly expressed only at the breaker stage when the ABA content becomes high. After this, the LeACS2, LeACS4, and LeACO1 genes were expressed with some delay. The change in pattern of ACO activity was in accordance with ethylene production reaching its peak at the pink stage. The maximum ABA content preceded ethylene production in both the seeds and the flesh. The peak value of ABA, ACC, and ACC oxidase activity, and ethylene production all started to increase earlier in seeds than in flesh tissues, although they occurred at different ripening stages. Exogenous ABA treatment increased the ABA content in both flesh and seed, inducing the expression of both ACS and ACO genes, and promoting ethylene synthesis and fruit ripening, while treatment with fluridone or nordihydroguaiaretic acid (NDGA) inhibited them, delaying fruit ripening and softening. Based on the results obtained in this study, it was concluded that LeNCED1 initiates ABA biosynthesis at the onset of fruit ripening, and might act as an original inducer, and ABA accumulation might play a key role in the regulation of ripeness and senescence of tomato fruit. PMID:19246595

  12. AbaA Regulates Conidiogenesis in the Ascomycete Fungus Fusarium graminearum

    PubMed Central

    Son, Hokyoung; Kim, Myung-Gu; Min, Kyunghun; Seo, Young-Su; Lim, Jae Yun; Choi, Gyung Ja; Kim, Jin-Cheol; Chae, Suhn-Kee; Lee, Yin-Won

    2013-01-01

    Fusarium graminearum (teleomorph Gibberella zeae) is a prominent pathogen that infects major cereal crops such as wheat, barley, and maize. Both sexual (ascospores) and asexual (conidia) spores are produced in F. graminearum. Since conidia are responsible for secondary infection in disease development, our objective of the present study was to reveal the molecular mechanisms underlying conidiogenesis in F. graminearum based on the framework previously described in Aspergillus nidulans. In this study, we firstly identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. Results from RNA-sequencing analysis suggest that AbaA plays a pivotal role in conidiation by regulating cell cycle pathways and other conidiation-related genes. Thus, the conserved roles of the AbaA ortholog in both A. nidulans and F. graminearum give new insight into the genetics of conidiation in filamentous fungi. PMID:24039821

  13. Genetic polymorphisms of estrogen receptor alpha and catechol-O-methyltransferase genes in Turkish patients with familial prostate carcinoma

    PubMed Central

    Pazarbasi, Ayfer; Yilmaz, M. Bertan; Alptekin, Davut; Luleyap, Umit; Tansug, Zuhtu; Ozpak, Lutfiye; Izmirli, Muzeyyen; Onatoglu-Arikan, Dilge; Kocaturk-Sel, Sabriye; Erkoc, Mehmet Ali; Turgut, Ozgur; Bereketoglu, Ceyhun; Tunc, Erdal; Akbal, Eylul

    2013-01-01

    OBJECTIVES: Estrogen is one of the most crucial hormones participating in the proliferation and carcinogenesis of the prostate glands. Genetic polymorphisms in the estrogen metabolism pathway might be involved in the risk of prostate carcinoma development. We evaluated the association between genetic polymorphisms in estrogen receptor alpha (ESR1) and catechol-O-methyltransferase (COMT) genes and the risk of developing familial prostate carcinoma. MATERIALS AND METHODS: In this study, 34 cases with prostate carcinoma whose first-degree relatives had prostate carcinoma and 30 healthy age-matched male controls were enrolled. The genotypes of ESR1 and COMT genes were analyzed employing polymerase chain reaction-restriction fragment length polymorphism method. 34 cases with prostate carcinoma, whose first degree relatives had prostate carcinoma and 14 age-matched male controls were enrolled to analyze the genotype of these two genes. RESULTS: Among control patients, the ESR1 PvuII genotypes of C/C, C/T and T/T were observed in 37%, 26% and 37%, respectively, whereas the C/C, C/T and T/T genotypes were observed in 18%, 41% and 41% of case patients, respectively. Among controls, the ESR1 PvuII allele frequencies of C and T were equally observed, whereas the C and T allele frequencies were observed in 38% and 62% of patients, respectively. Among ESR1 PvuII genotypes there were not any significant difference in terms of genotype (P = 0.199) and allele (P = 0.181) frequencies. Among controls, the ESR1 XbaI genotypes of G/G, G/A and A/A were observed in 33%, 37% and 33%, respectively, whereas the G/G, G/A and A/A genotypes were observed in 12%, 47% and 41% of patients, respectively. Among controls, the ESR1 XbaI allele frequencies of A and G were observed equally, respectively, whereas the A and G frequencies were observed in 65% and 35% of patients, respectively. Among ESR1 Χ baI, there was not any significant difference in terms of genotype (P = 0.111) and allele (P = 0

  14. N-Benzyl-5-methoxytryptamines as Potent Serotonin 5-HT2 Receptor Family Agonists and Comparison with a Series of Phenethylamine Analogues

    PubMed Central

    2015-01-01

    A series of N-benzylated-5-methoxytryptamine analogues was prepared and investigated, with special emphasis on substituents in the meta position of the benzyl group. A parallel series of several N-benzylated analogues of 2,5-dimethoxy-4-iodophenethylamine (2C-I) also was included for comparison of the two major templates (i.e., tryptamine and phenethylamine). A broad affinity screen at serotonin receptors showed that most of the compounds had the highest affinity at the 5-HT2 family receptors. Substitution at the para position of the benzyl group resulted in reduced affinity, whereas substitution in either the ortho or the meta position enhanced affinity. In general, introduction of a large lipophilic group improved affinity, whereas functional activity often followed the opposite trend. Tests of the compounds for functional activity utilized intracellular Ca2+ mobilization. Function was measured at the human 5-HT2A, 5-HT2B, and 5-HT2C receptors, as well as at the rat 5-HT2A and 5-HT2C receptors. There was no general correlation between affinity and function. Several of the tryptamine congeners were very potent functionally (EC50 values from 7.6 to 63 nM), but most were partial agonists. Tests in the mouse head twitch assay revealed that many of the compounds induced the head twitch and that there was a significant correlation between this behavior and functional potency at the rat 5-HT2A receptor. PMID:25547199

  15. The three-dimensional structure of the N-terminal domain of corticotropin-releasing factor receptors: sushi domains and the B1 family of G protein-coupled receptors.

    PubMed

    Perrin, Marilyn H; Grace, Christy R R; Riek, Roland; Vale, Wylie W

    2006-07-01

    The corticotropin-releasing factor (CRF) receptors, CRF-R1 and CRF-R2, belong to the B1 subfamily of G protein-coupled Receptors (GPCRs), including receptors for secretin, growth hormone-releasing hormone (GHRH), vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), calcitonin, parathyroid hormone (PTH), glucagon, and glucagon-like peptide-1 (GLP-1). The peptide ligand family comprises CRF, Ucn 1, 2, and 3. CRF plays the major role in integrating the response to stress. Additionally, the ligands exhibit many effects on muscle, pancreas, heart, and the GI, reproductive, and immune systems. CRF-R1 has higher affinity for CRF than does CRF-R2 while both receptors bind Ucn 1 equally. CRF-R2 shows specificity for Ucns 2 and 3. A major binding domain of the CRFRs is the N terminus/first extracellular domain (ECD1). Soluble proteins corresponding to the ECD1s of each receptor bind CRF ligands with nanomolar affinities. Our three-dimensional (3D) nuclear magnetic resonance (NMR) structure of a soluble protein corresponding to the ECD1 of CRF-R2beta (1) identified its structural fold as a Sushi domain/short consensus repeat (SCR), stabilized by three disulfide bridges, two tryptophan residues, and an internal salt bridge (Asp65-Arg101). Disruption of the bridge by D65A mutation abrogates ligand recognition and results in loss of the well-defined disulfide pattern and Sushi domain structure. NMR analysis of the ECD1 in complex with astressin identified key amino acids involved in ligand recognition. Mutation of some of these residues in the full-length receptor reduces its affinity for CRF ligands. A structure-based sequence comparison shows conservation of key amino acids in all the B1 subfamily receptors, suggesting a corresponding conservation of a Sushi domain structural fold of their ECD1s.

  16. A Maize Jasmonate Zim-Domain Protein, ZmJAZ14, Associates with the JA, ABA, and GA Signaling Pathways in Transgenic Arabidopsis

    PubMed Central

    Li, Suzhen; Li, Jie; Xu, Miaoyun; Liu, Xiaoqing; Zhang, Shaojun; Zhao, Qianqian; Li, Ye; Fan, Yunliu; Chen, Rumei; Wang, Lei

    2015-01-01

    Jasmonate (JA) is an important signaling molecule involved in the regulation of many physiological and stress-related processes in plants. Jasmonate ZIM-domain (JAZ) proteins have been implicated in regulating JA signaling pathways and the cross talk between various phytohormones. Maize is not only an important cereal crop, but also a model plant for monocotyledon studies. Although many JAZ proteins have been characterized in Arabidopsis and rice, few reports have examined the function of JAZ proteins in maize. In this report, we examined the phylogenetic relationship and expression pattern of JAZ family genes in maize. In addition, a tassel and endosperm-specific JAZ gene, ZmJAZ14, was identified using microarray data analysis and real-time RT-PCR, and its expression was induced by polyethylene glycol (PEG), jasmonate (JA), abscisic acid (ABA), and gibberellins (GAs). ZmJAZ14 was shown to be localized in the nucleus and possessed no transcriptional activating activity, suggesting that it functions as a transcriptional regulator. We found that overexpression of ZmJAZ14 in Arabidopsis enhanced plant tolerance to JA and ABA treatment, as well as PEG stress, while it promoted growth under GA stimulus. Moreover, ZmJAZ14 interacted with a subset of transcription factors in Arabidopsis, and the accumulation of several marker genes involved in JA, ABA, and GA signaling pathways were altered in the overexpression lines. These results suggest that ZmJAZ14 may serve as a hub for the cross talk among the JA, ABA, and GA signaling pathways. Our results can be used to further characterize the function of JAZ family proteins in maize, and the gene cloned in this study may serve as a candidate for drought tolerance and growth promotion regulation in maize. PMID:25807368

  17. Self-assembly of ABA triblock copolymers under soft confinement

    NASA Astrophysics Data System (ADS)

    Sheng, Yuping; An, Jian; Zhu, Yutian

    2015-05-01

    Using Monte Carlo method, the self-assembly of ABA triblock copolymers under soft confinement is investigated in this study. The soft confinement is achieved by a poor solvent environment for the polymer, which makes the polymer aggregate into a droplet. Various effects, including the block length ratio, the solvent quality for the blocks B, and the incompatibility between blocks A and B, on the micellar structures induced by soft confinement are examined. By increasing the solvent quality of B blocks, the micellar structure transforms from stacked lamella to bud-like structure, and then to onion-like structure for A5B8A5 triblock copolymers, while the inner micellar structure changes from spherical phase to various cylindrical phase, such as inner single helix, double helixes, stacked rings and cage-like structures, for A7B4A7 triblock copolymers. Moreover, the formation pathways of some typical aggregates are examined to illustrate their growth mechanisms.

  18. 40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... foam production—HAP ABA equipment leaks. Each owner or operator of a new or existing slabstock affected... control HAP ABA emissions from leaks from transfer pumps, valves, connectors, pressure-relief valves,...

  19. 40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... foam production—HAP ABA storage vessels. Each owner or operator of a new or existing slabstock affected... control HAP ABA storage vessels in accordance with the provisions of this section. (a) Each HAP...

  20. NADPH oxidase AtrbohD and AtrbohF genes function in ROS-dependent ABA signaling in Arabidopsis.

    PubMed

    Kwak, June M; Mori, Izumi C; Pei, Zhen-Ming; Leonhardt, Nathalie; Torres, Miguel Angel; Dangl, Jeffery L; Bloom, Rachel E; Bodde, Sara; Jones, Jonathan D G; Schroeder, Julian I

    2003-06-01

    Reactive oxygen species (ROS) have been proposed to function as second messengers in abscisic acid (ABA) signaling in guard cells. However, the question whether ROS production is indeed required for ABA signal transduction in vivo has not yet been addressed, and the molecular mechanisms mediating ROS production during ABA signaling remain unknown. Here, we report identification of two partially redundant Arabidopsis guard cell-expressed NADPH oxidase catalytic subunit genes, AtrbohD and AtrbohF, in which gene disruption impairs ABA signaling. atrbohD/F double mutations impair ABA-induced stomatal closing, ABA promotion of ROS production, ABA-induced cytosolic Ca(2+) increases and ABA- activation of plasma membrane Ca(2+)-permeable channels in guard cells. Exogenous H(2)O(2) rescues both Ca(2+) channel activation and stomatal closing in atrbohD/F. ABA inhibition of seed germination and root elongation are impaired in atrbohD/F, suggesting more general roles for ROS and NADPH oxidases in ABA signaling. These data provide direct molecular genetic and cell biological evidence that ROS are rate-limiting second messengers in ABA signaling, and that the AtrbohD and AtrbohF NADPH oxidases function in guard cell ABA signal transduction.

  1. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance

    PubMed Central

    Lu, Kai; Liang, Shan; Wu, Zhen; Bi, Chao; Yu, Yong-Tao; Wang, Xiao-Fang; Zhang, Da-Peng

    2016-01-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana. Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 K372E with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. PMID:27406784

  2. An ochre mutation in the vitamin D receptor gene causes hereditary 1,25-dihydroxyvitamin D sub 3 -resistant rickets in three families

    SciTech Connect

    Ritchie, H.H.; Hughes, M.R.; Thompson, E.T.; Pike, J.W.; O'Malley, B.W. ); Malloy, P.J.; Feldman, D. ); Hochberg, Z. )

    1989-12-01

    Hereditary 1,25-dihydroxyvitamin D{sub 3}-resistant rickets is a rare autosomal-recessive disease resulting from target-organ resistance to the action of the active hormonal form of vitamin D. Four affected children from three related families with the classical syndrome of hereditary 1,25-dihydroxyvitamin D{sub 3}-resistant rickets and the absence of detectable binding to the vitamin D receptor (VDR) in cultured fibroblasts or lymphoblasts were examined for genetic abnormalities in the VDR gene. Genomic DNA from Epstein-Barr virus-transformed lymphoblasts of eight family members was isolated and amplified by polymerase chain reaction techniques. Amplified fragments containing the eight structural exons encoding the VDR protein were sequenced. The DNA from all affected children exhibited a single C {yields} A base substitution within exon 7 at nucleotide 970. Although the affected children were all homozygotic for the mutation, the four parents tested all exhibited both wild-type and mutant alleles, indicating a heterozygous state. Recreated mutant receptor exhibited no specific 1,25-({sup 3}H)dihydroxyvitamin D{sub 3} binding and failed to activate a cotransfected VDR promoter-reporter gene construct. Thus these findings identify an ochre mutation in a human steroid hormone receptor in patients with hereditary 1,25-dihydroxyvitamin D{sub 3}-resistant rickets.

  3. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis1[OPEN

    PubMed Central

    Wang, Zhen-Yu; Gehring, Chris; Zhu, Jianhua; Li, Feng-Min; Zhu, Jian-Kang; Xiong, Liming

    2015-01-01

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1. PMID:25416474

  4. The Arabidopsis transcription factor ABIG1 relays ABA signaled growth inhibition and drought induced senescence

    PubMed Central

    Liu, Tie; Longhurst, Adam D; Talavera-Rauh, Franklin; Hokin, Samuel A; Barton, M Kathryn

    2016-01-01

    Drought inhibits plant growth and can also induce premature senescence. Here we identify a transcription factor, ABA INSENSITIVE GROWTH 1 (ABIG1) required for abscisic acid (ABA) mediated growth inhibition, but not for stomatal closure. ABIG1 mRNA levels are increased both in response to drought and in response to ABA treatment. When treated with ABA, abig1 mutants remain greener and produce more leaves than comparable wild-type plants. When challenged with drought, abig1 mutants have fewer yellow, senesced leaves than wild-type. Induction of ABIG1 transcription mimics ABA treatment and regulates a set of genes implicated in stress responses. We propose a model in which drought acts through ABA to increase ABIG1 transcription which in turn restricts new shoot growth and promotes leaf senescence. The results have implications for plant breeding: the existence of a mutant that is both ABA resistant and drought resistant points to new strategies for isolating drought resistant genetic varieties. DOI: http://dx.doi.org/10.7554/eLife.13768.001 PMID:27697148

  5. Endodermal ABA signaling promotes lateral root quiescence during salt stress in Arabidopsis seedlings.

    PubMed

    Duan, Lina; Dietrich, Daniela; Ng, Chong Han; Chan, Penny Mei Yeen; Bhalerao, Rishikesh; Bennett, Malcolm J; Dinneny, José R

    2013-01-01

    The endodermal tissue layer is found in the roots of vascular plants and functions as a semipermeable barrier, regulating the transport of solutes from the soil into the vascular stream. As a gateway for solutes, the endodermis may also serve as an important site for sensing and responding to useful or toxic substances in the environment. Here, we show that high salinity, an environmental stress widely impacting agricultural land, regulates growth of the seedling root system through a signaling network operating primarily in the endodermis. We report that salt stress induces an extended quiescent phase in postemergence lateral roots (LRs) whereby the rate of growth is suppressed for several days before recovery begins. Quiescence is correlated with sustained abscisic acid (ABA) response in LRs and is dependent upon genes necessary for ABA biosynthesis, signaling, and transcriptional regulation. We use a tissue-specific strategy to identify the key cell layers where ABA signaling acts to regulate growth. In the endodermis, misexpression of the ABA insensitive1-1 mutant protein, which dominantly inhibits ABA signaling, leads to a substantial recovery in LR growth under salt stress conditions. Gibberellic acid signaling, which antagonizes the ABA pathway, also acts primarily in the endodermis, and we define the crosstalk between these two hormones. Our results identify the endodermis as a gateway with an ABA-dependent guard, which prevents root growth into saline environments.

  6. Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J

    2016-07-01

    Stomatal responses to changes in vapor pressure deficit (VPD) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability.

  7. Loss of ACS7 confers abiotic stress tolerance by modulating ABA sensitivity and accumulation in Arabidopsis.

    PubMed

    Dong, Hui; Zhen, Zhiqin; Peng, Jinying; Chang, Li; Gong, Qingqiu; Wang, Ning Ning

    2011-10-01

    The phytohormones ethylene and abscisic acid (ABA) play essential roles in the abiotic stress adaptation of plants, with both cross-talk of ethylene signalling and ABA biosynthesis and signalling reported. Any reciprocal effects on each other's biosynthesis, however, remain elusive. ACC synthase (ACS) acts as the key enzyme in ethylene biosynthesis. A pilot study on changes in ACS promoter activities in response to abiotic stresses revealed the unique involvement in abiotic stress responses of the only type 3 ACC synthase, ACS7, among all nine ACSs of Arabidopsis. Hence an acs7 mutant was characterized and its abiotic stress responses were analysed. The acs7 mutant germinated slightly faster than the wild type and subsequently maintained a higher growth rate at the vegetative growth stage. Ethylene emission of acs7 was merely one-third of that of the wild type. acs7 exhibited enhanced tolerance to salt, osmotic, and heat stresses. Furthermore, acs7 seeds were hypersensitive to both ABA and glucose during germination. Transcript analyses revealed that acs7 had elevated transcript levels of the stress-responsive genes involved in the ABA-dependent pathway under salt stress. The ABA level was also higher in acs7 following salt treatment. Our data suggest that ACS7 acts as a negative regulator of ABA sensitivity and accumulation under stress and appears as a node in the cross-talk between ethylene and ABA.

  8. Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J

    2016-07-01

    Stomatal responses to changes in vapor pressure deficit (VPD) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability. PMID:27208264

  9. [Role of NO signal in ABA-induced phenolic acids accumulation in Salvia miltiorrhiza hairy roots].

    PubMed

    Shen, Lihong; Ren, Jiahui; Jin, Wenfang; Wang, Ruijie; Ni, Chunhong; Tong, Mengjiao; Liang, Zongsuo; Yang, Dongfeng

    2016-02-01

    To investigate roles of nitric oxide (NO) signal in accumulations of phenolic acids in abscisic.acid (ABA)-induced Salvia miltiorrhiza hairy roots, S. miltiorrhiza hairy roots were treated with different concentrations of sodium nitroprusside (SNP)-an exogenous NO donor, for 6 days, and contents of phenolic acids in the hairy roots are determined. Then with treatment of ABA and NO scavenger (2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1- oxyl-3-oxide, c-PTIO) or NO synthase inhibitor (NG-nitro-L-arginine methyl ester, L-NAME), contents of phenolic acids and expression levels of three key genes involved in phenolic acids biosynthesis were detected. Phenolic acids production in S. miltiorrhiza hairy roots was most significantly improved by 100 µmoL/L SNP. Contents of RA and salvianolic acid B increased by 3 and 4 folds. ABA significantly improved transcript levels of PAL (phenylalanine ammonia lyase), TAT (tyrosine aminotransferase) and RAS (rosmarinic acid synthase), and increased phenolic acids accumulations. However, with treatments of ABA+c-PTIO or ABA+L-NAME, accumulations of phenolic acids and expression levels of the three key genes were significantly inhibited. Both NO and ABA can increase accumulations of phenolic acids in S. miltiorrhiza hairy roots. NO signal probably mediates the ABA-induced phenolic acids production. PMID:27382772

  10. ABA is required for Leptosphaeria maculans resistance via ABI1- and ABI4-dependent signaling.

    PubMed

    Kaliff, Maria; Staal, Jens; Myrenås, Mattias; Dixelius, Christina

    2007-04-01

    Abscisic acid (ABA) is a defense hormone with influence on callose-dependent and -independent resistance against Leptosphaeria maculans acting in the RLMcol pathway. ABA-deficient and -insensitive mutants in Ler-0 background (abal-3 and abil-1) displayed susceptibility to L. maculans, along with a significantly decreased level of callose depositions, whereas abi2-1 and abi3-1 remained resistant, together with the abi5-1 mutant of Ws-0 background. Suppressor mutants of abil-1 confirmed that the L. maculans-susceptible response was due to the dominant negative nature of the abil-1 mutant. Highly induced camalexin levels made ABA mutants in Col-0 background (aba2-1, aba3-1, and abi4-1) appear resistant, but displayed enhanced susceptibility as double mutants with pad3-1, impaired in camalexin biosynthesis. beta-Aminobutyric acid (BABA) pretreatment of Ler-0 contributed to an elevated level of endogenous ABA after L. maculans inoculation. Comparisons between (RLM1co1)pad3 and rlmlLerpad3 showed that ABA and BABA enhancement of callose deposition requires induction from RLM1col. ABII, but not ABI2, was found to be involved in a feedback mechanism that modulates RLM1co, expression. Genetic analysis showed further that this feedback occurs upstream of ABI4 and that components downstream of ABI4 modulate ABIJ activity. ABA and BABA treatments of the L. maculans-susceptible callose synthase mutant pmr4 showed that ABA also induces a callose-independent resistance. Similar treatments enhanced callose depositions and induced resistance to L. maculans in oilseed rape, and BABA-induced resistance was found to be independent of salicylic acid.

  11. POLYAMINE OXIDASE2 of Arabidopsis contributes to ABA mediated plant developmental processes.

    PubMed

    Wimalasekera, Rinukshi; Schaarschmidt, Frank; Angelini, Riccardo; Cona, Alessandra; Tavladoraki, Parasklevi; Scherer, Günther F E

    2015-11-01

    Polyamines (PA) are catabolised by two groups of amine oxidases, the copper-binding amine oxidases (CuAOs) and the FAD-binding polyamine oxidases (PAOs). Previously, we have shown that CuAO1 is involved in ABA associated growth responses and ABA- and PA-mediated rapid nitric oxide (NO) production. Here we report the differential regulation of expression of POLYAMINE OXIDASE2 of Arabidopsis (AtPAO2) in interaction with ABA, nitrate and ammonium. Without ABA treatment germination, cotyledon growth and fresh weight of pao2 knockdown mutants as well as PAO2OX over-expressor plants were comparable to those of the wild type (WT) plants irrespective of the N source. In the presence of ABA, in pao2 mutants cotyledon growth and fresh weights were more sensitive to inhibition by ABA while PAO2OX over-expressor plants showed a rather similar response to WT. When NO3(-) was the only N source primary root lengths and lateral root numbers were lower in pao2 mutants both without and with exogenous ABA. PAO2OX showed enhanced primary and lateral root growth in media with NO3(-) or NH4(+). Vigorous root growth of PAO2OX and the hypersensitivity of pao2 mutants to ABA suggest a positive function of AtPAO2 in root growth. ABA-induced NO production in pao2 mutants was lower indicating a potential contributory function of AtPAO2 in NO-mediated effects on root growth. PMID:26310141

  12. A new point mutation (C446R) in the thyroid hormone receptor-{beta} gene of a family with resistance to thyroid hormone

    SciTech Connect

    Weiss, R.E.; Chyna, B.; Hayashi, Yoshitaka; Sunthornthepvarakul, T.; Refetoff, S.; Duell, P.B.

    1994-05-01

    Resistance to thyroid hormone (RTH) is a condition of impaired end-organ responsiveness to thyroid hormone characterized by goiter and elevated thyroid hormone levels with an appropriately normal TSH. RTH has been associated with mutations in the thyroid hormone receptor-{beta} (TR{beta}) gene. The authors report studies carried out in 21 members of a family (F119), 12 of whom exhibited the RTH phenotype. A point mutation was detected in the T{sub 3}-binding domain of the TR{beta} gene. It resulted in replacement of the normal cysteine-446 with an arginine (C446R) that has not been previously reported. The clinical characteristics of this family are similar to those reported in other families with RTH, namely goiter, tachycardia, and learning disabilities. Thyroid function tests are also typical of other subjects with RTH. The mean values ({+-}SD) in untreated affected subjects compared to those in unaffected family members were: free T{sub 4} index, 250 {+-} 21 vs. 108 {+-} 13; total T{sub 3}, 4.3 {+-} 0.4 vs. 2.4 {+-} 0.4 nmol/L; and TSH, 4.5 {+-} 1.1 vs. 2.4 {+-} 1.1 mU/L. DNA samples from 18 family members were screened for the TR{beta} mutation, which results in the loss of a BsmI restriction site, and each of the 11 subjects with abnormal thyroid function tests were heterozygous for the mutant allele. The mutant TR{beta} expressed in Cos-I cells did not bind T{sub 3} (K{sub a} of C446R/wild-type, <0.05). T{sub 3} at a concentration up to 100 nmol/L failed to enhance the transactivation of a reporter gene, and the mutant receptor inhibited the T{sub 3}-mediated transcriptional activation of the wild-type TR{beta}. 17 refs., 3 figs., 1 tab.

  13. Evidence for a partial deficiency of the LDL (apo B,E) receptor within a family of rhesus monkeys with a spontaneous hypercholesterolemia

    SciTech Connect

    Scanu, A.M.; Khalil, A.; Tidore, M.; Kaiser, M.; Pfaffinger, D.; Carey, D.; Dawson, G.

    1987-05-01

    Spontaneous hypercholesterolemia is rare among non-human primates. Through screening of a rhesus monkey colony they have identified a family in which 3 out of its 6 members have a persistent hypercholesterolemia on a cholesterol-free Purina Chow diet and are high responders to a dietary fat challenge. On a basal diet the 3 affected animals also exhibited high plasma levels of LDL and apoB. To shed light on the mechanism of the hypercholesterolemia they have grown in culture fibroblasts from skin biopsies obtained from all members of the rhesus monkey family and 12 control. Binding studies at 4/sup 0/C and ligand blotting experiments using /sup 125/I-LDL of either normolipidemic rhesus monkeys or human subjects have shown that the fibroblasts from the 3 monkeys with a spontaneous hypercholesterolemia have a significant reduction of the number of LDL receptor and to the same extent as fibroblasts derived from subjects with heterozygous FH studied at the same time. The data suggest that the spontaneous elevation of plasma cholesterol observed in the 3 family members is related, at least in part, to a defective uptake of LDL by the LDL receptor pathway.

  14. Loss of heterophylly in aquatic plants: not ABA-mediated stress but exogenous ABA treatment induces stomatal leaves in Potamogeton perfoliatus.

    PubMed

    Iida, Satoko; Ikeda, Miyuki; Amano, Momoe; Sakayama, Hidetoshi; Kadono, Yasuro; Kosuge, Keiko

    2016-09-01

    Heterophyllous aquatic plants produce aerial (i.e., floating and terrestrial) and submerged leaves-the latter lack stomata-while homophyllous plants contain only submerged leaves, and cannot survive on land. To identify whether differences in morphogenetic potential and/or physiological stress responses are responsible for variation in phenotypic plasticity between two plants types, responses to abscisic acid (ABA) and salinity stress were compared between the closely related, but ecologically diverse pondweeds, Potamogeton wrightii (heterophyllous) and P. perfoliatus (homophyllous). The ABA-treated (1 or 10 μM) P. wrightii plants exhibited heterophylly and produced leaves with stomata. The obligate submerged P. perfoliatus plants were able to produce stomata on their leaves, but there were no changes to leaf shape, and stomatal production occurred only at a high ABA concentration (10 μM). Under salinity stress conditions, only P. wrightii leaves formed stomata. Additionally, the expression of stress-responsive NCED genes, which encode a key enzyme in ABA biosynthesis, was consistently up-regulated in P. wrightii, but only temporarily in P. perfoliatus. The observed species-specific gene expression patterns may be responsible for the induction or suppression of stomatal production during exposure to salinity stress. These results suggest that the two Potamogeton species have an innate morphogenetic ability to form stomata, but the actual production of stomata depends on ABA-mediated stress responses specific to each species and habitat. PMID:27324202

  15. Rice salT promoter is activated in Papaver somniferum and Nicotiana tabacum transgenic cells in the absence of exogenous ABA.

    PubMed

    Elleuch; Belbahri; Boetti; David; Thomassetb; David

    2001-01-01

    With the aim of modifying secondary metabolism in Opium poppy (Papaver somniferum) and tobacco (Nicotiana tabacum) cells, gene transfer was performed using the sam1 gene from Arabidopsis thaliana under the control of the salT promoter. This promoter is induced by ABA in rice and in tobacco and we have shown that it is also induced in poppy cells (gus gene). Putatively transformed poppy and tobacco cell lines with the sam1 gene were obtained. In the absence of exogenous inducer we noticed the expression of the transgene resulting in a significant increase of SAM-S activity in all tested transformants of poppy and in half the transgenic tobacco cell lines tested. Addition of ABA to the culture medium failed to enhance the expression of the transgene in both species and resulted in a decrease of the sam1 gene expression in some cell lines. Since the salT promoter is induced by exogenous ABA in both species (gus reporter gene), we suggest a partial sam1 transgene inactivation in certain cell lines. These results show that the efficiency of a regulatory sequence may be different when fused with a reporter gene (gus) compared to fusion with a gene belonging to the housekeeping family (sam1).

  16. High relative air humidity and continuous light reduce stomata functionality by affecting the ABA regulation in rose leaves.

    PubMed

    Arve, Louise E; Terfa, Meseret T; Gislerød, Hans Ragnar; Olsen, Jorunn E; Torre, Sissel

    2013-02-01

    Plants developed under high (90%) relative air humidity (RH) have previously been shown to have large, malfunctioning stomata, which results in high water loss during desiccation and reduced dark induced closure. Stomatal movement is to a large extent regulated by abscisic acid (ABA). It has therefore been proposed that low ABA levels contribute to the development of malfunctioning stomata. In this study, we investigated the regulation of ABA content in rose leaves, through hormone analysis and β-glucosidase quantification. Compared with high RH, rose plants developed in moderate RH (60%) and 20 h photoperiod contained higher levels of ABA and β-glucosidase activity. Also, the amount of ABA increased during darkness simultaneously as the ABA-glucose ester (GE) levels decreased. In contrast, plants developed under high RH with 20 h photoperiod showed no increase in ABA levels during darkness, and had low β-glucosidase activity converting ABA-GE to ABA. Continuous lighting (24 h) resulted in low levels of β-glucosidase activity irrespective of RH, indicating that a dark period is essential to activate β-glucosidase. Our results provide new insight into the regulation of ABA under different humidities and photoperiods, and clearly show that β-glucosidase is a key enzyme regulating the ABA pool in rose plants. PMID:22812416

  17. Increased ABA sensitivity results in higher seed dormancy in soft white spring wheat cultivar ‘Zak’

    PubMed Central

    Schramm, Elizabeth C.; Nelson, Sven K.; Kidwell, Kimberlee K.

    2014-01-01

    As a strategy to increase the seed dormancy of soft white wheat, mutants with increased sensitivity to the plant hormone abscisic acid (ABA) were identified in mutagenized grain of soft white spring wheat “Zak”. Lack of seed dormancy is correlated with increased susceptibility to preharvest sprouting in wheat, especially those cultivars with white kernels. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature grain. Three mutant lines called Zak ERA8, Zak ERA19A, and Zak ERA19B (Zak ENHANCED RESPONSE to ABA) were recovered based on failure to germinate on 5 µM ABA. All three mutants resulted in increased ABA sensitivity over a wide range of concentrations such that a phenotype can be detected at very low ABA concentrations. Wheat loses sensitivity to ABA inhibition of germination with extended periods of dry after-ripening. All three mutants recovered required more time to after-ripen sufficiently to germinate in the absence of ABA and to lose sensitivity to 5 µM ABA. However, an increase in ABA sensitivity could be detected after as long as 3 years of after-ripening using high ABA concentrations. The Zak ERA8 line showed the strongest phenotype and segregated as a single semi-dominant mutation. This mutation resulted in no obvious decrease in yield and is a good candidate gene for breeding preharvest sprouting tolerance. PMID:23212773

  18. Arabidopsis CPR5 Independently Regulates Seed Germination and Postgermination Arrest of Development through LOX Pathway and ABA Signaling

    PubMed Central

    Yang, Xiang; Wang, Yaqin; Su, Xiaojun; Du, Jinju; Yang, Chengwei

    2011-01-01

    The phytohormone abscisic acid (ABA) and the lipoxygenases (LOXs) pathway play important roles in seed germination and seedling growth and development. Here, we reported on the functional characterization of Arabidopsis CPR5 in the ABA signaling and LOX pathways. The cpr5 mutant was hypersensitive to ABA in the seed germination, cotyledon greening and root growth, whereas transgenic plants overexpressing CPR5 were insensitive. Genetic analysis demonstrated that CPR5 gene may be located downstream of the ABI1 in the ABA signaling pathway. However, the cpr5 mutant showed an ABA independent drought-resistant phenotype. It was also found that the cpr5 mutant was hypersensitive to NDGA and NDGA treatment aggravated the ABA-induced delay in the seed germination and cotyledon greening. Taken together, these results suggest that the CPR5 plays a regulatory role in the regulation of seed germination and early seedling growth through ABA and LOX pathways independently. PMID:21556325

  19. The molecular evolutionary dynamics of the vomeronasal receptor (class 1) genes in primates: a gene family on the verge of a functional breakdown

    PubMed Central

    Yoder, Anne D.; Larsen, Peter A.

    2014-01-01

    Olfaction plays a critical role in both survival of the individual and in the propagation of species. Studies from across the mammalian clade have found a remarkable correlation between organismal lifestyle and molecular evolutionary properties of receptor genes in both the main olfactory system (MOS) and the vomeronasal system (VNS). When a large proportion of intact (and putatively functional) copies is observed, the inference is made that a particular mode of chemoreception is critical for an organism’s fit to its environment and is thus under strong positive selection. Conversely, when the receptors in question show a disproportionately large number of pseudogene copies, this contraction is interpreted as evidence of relaxed selection potentially leading to gene family extinction. Notably, it appears that a risk factor for gene family extinction is a high rate of nonsynonymous substitution. A survey of intact vs. pseudogene copies among primate vomeronasal receptor Class one genes (V1Rs) appears to substantiate this hypothesis. Molecular evolutionary complexities in the V1R gene family combine rapid rates of gene duplication, gene conversion, lineage-specific expansions, deletions, and/or pseudogenization. An intricate mix of phylogenetic footprints and current adaptive landscapes have left their mark on primate V1Rs suggesting that the primate clade offers an ideal model system for exploring the molecular evolutionary and functional properties of the VNS of mammals. Primate V1Rs tell a story of ancestral function and divergent selection as species have moved into ever diversifying adaptive regimes. The sensitivity to functional collapse in these genes, consequent to their precariously high rates of nonsynonymous substitution, confer a remarkable capacity to reveal the lifestyles of the genomes that they presently occupy as well as those of their ancestors. PMID:25565978

  20. Taci Is a Traf-Interacting Receptor for Tall-1, a Tumor Necrosis Factor Family Member Involved in B Cell Regulation

    PubMed Central

    Xia, Xing-Zhong; Treanor, James; Senaldi, Giorgio; Khare, Sanjay D.; Boone, Tom; Kelley, Michael; Theill, Lars E.; Colombero, Anne; Solovyev, Irina; Lee, Frances; McCabe, Susan; Elliott, Robin; Miner, Kent; Hawkins, Nessa; Guo, Jane; Stolina, Marina; Yu, Gang; Wang, Judy; Delaney, John; Meng, Shi-Yuan; Boyle, William J.; Hsu, Hailing

    2000-01-01

    We and others recently reported tumor necrosis factor (TNF) and apoptosis ligand–related leukocyte-expressed ligand 1 (TALL-1) as a novel member of the TNF ligand family that is functionally involved in B cell proliferation. Transgenic mice overexpressing TALL-1 have severe B cell hyperplasia and lupus-like autoimmune disease. Here, we describe expression cloning of a cell surface receptor for TALL-1 from a human Burkitt's lymphoma RAJI cell library. The cloned receptor is identical to the previously reported TNF receptor (TNFR) homologue transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI). Murine TACI was subsequently isolated from the mouse B lymphoma A20 cells. Human and murine TACI share 54% identity overall. Human TACI exhibits high binding affinities to both human and murine TALL-1. Soluble TACI extracellular domain protein specifically blocks TALL-1–mediated B cell proliferation without affecting CD40- or lipopolysaccharide-mediated B cell proliferation in vitro. In addition, when injected into mice, soluble TACI inhibits antibody production to both T cell–dependent and –independent antigens. By yeast two-hybrid screening of a B cell library with TACI intracellular domain, we identified that, like many other TNFR family members, TACI intracellular domain interacts with TNFR-associated factor (TRAF)2, 5, and 6. Correspondingly, TACI activation in a B cell line results in nuclear factor κB and c-Jun NH2-terminal kinase activation. The identification and characterization of the receptor for TALL-1 provides useful information for the development of a treatment for B cell–mediated autoimmune diseases such as systemic lupus erythematosus. PMID:10880535

  1. Differences in respiration between dormant and non-dormant buds suggest the involvement of ABA in the development of endodormancy in grapevines.

    PubMed

    Parada, Francisca; Noriega, Ximena; Dantas, Débora; Bressan-Smith, Ricardo; Pérez, Francisco J

    2016-08-20

    Grapevine buds (Vitis vinifera L) enter endodormancy (ED) after perceiving the short-day (SD) photoperiod signal and undergo metabolic changes that allow them to survive the winter temperatures. In the present study, we observed an inverse relationship between the depth of ED and the respiration rate of grapevine buds. Moreover, the respiration of dormant and non-dormant buds differed in response to temperature and glucose, two stimuli that normally increase respiration in plant tissues. While respiration in non-dormant buds rose sharply in response to both stimuli, respiration in dormant buds was only slightly affected. This suggests that a metabolic inhibitor is present. Here, we propose that the plant hormone abscisic acid (ABA) could be this inhibitor. ABA inhibits respiration in non-dormant buds and represses the expression of respiratory genes, such as ALTERNATIVE NADH DEHYDROGENASE (VaND1, VvaND2), CYTOCHROME OXIDASE (VvCOX6) and CYTOCHROME C (VvCYTC), and induces the expression of VvSnRK1, a gene encoding a member of a highly conserved family of protein kinases that act as energy sensors and regulate gene expression in response to energy depletion. In addition to inducing ED the SD-photoperiod up-regulated the expression of VvNCED, a gene that encodes a key enzyme in ABA synthesis. Taken together, these results suggest that ABA through the mediation of VvSnRK1, could play a key role in the regulation of the metabolic changes accompanying the entry into ED of grapevine buds. PMID:27448722

  2. Molecular Characterization and Sex Distribution of Chemosensory Receptor Gene Family Based on Transcriptome Analysis of Scaeva pyrastri

    PubMed Central

    Li, Xiao-Ming; Zhu, Xiu-Yun; He, Peng; Xu, Lu; Sun, Liang; Chen, Li; Wang, Zhi-Qiang; Deng, Dao-Gui

    2016-01-01

    Chemosensory receptors play key roles in insect behavior. Thus, genes encoding these receptors have great potential for use in integrated pest management. The hover fly Scaeva pyrastri (L.) is an important pollinating insect and a natural enemy of aphids, mainly distributed in the Palearctic and Nearctic regions. However, a systematic identification of their chemosensory receptor genes in the antennae has not been reported. In the present study, we assembled the antennal transcriptome of S. pyrastri by using Illumina sequencing technology. Analysis of the transcriptome data identified 60 candidate chemosensory genes, including 38 for odorant receptors (ORs), 16 for ionotropic receptors (IRs), and 6 for gustatory receptors (GRs). The numbers are similar to those of other Diptera species, suggesting that we were able to successfully identify S. pyrastri chemosensory genes. We analyzed the expression patterns of all genes by using reverse transcriptase PCR (RT-PCR), and found that some genes exhibited sex-biased or sex-specific expression. These candidate chemosensory genes and their tissue expression profiles provide information for further studies aimed at fully understanding the molecular basis behind chemoreception-related behaviors in S. pyrastri. PMID:27171401

  3. Molecular Characterization and Sex Distribution of Chemosensory Receptor Gene Family Based on Transcriptome Analysis of Scaeva pyrastri.

    PubMed

    Li, Xiao-Ming; Zhu, Xiu-Yun; He, Peng; Xu, Lu; Sun, Liang; Chen, Li; Wang, Zhi-Qiang; Deng, Dao-Gui; Zhang, Ya-Nan

    2016-01-01

    Chemosensory receptors play key roles in insect behavior. Thus, genes encoding these receptors have great potential for use in integrated pest management. The hover fly Scaeva pyrastri (L.) is an important pollinating insect and a natural enemy of aphids, mainly distributed in the Palearctic and Nearctic regions. However, a systematic identification of their chemosensory receptor genes in the antennae has not been reported. In the present study, we assembled the antennal transcriptome of S. pyrastri by using Illumina sequencing technology. Analysis of the transcriptome data identified 60 candidate chemosensory genes, including 38 for odorant receptors (ORs), 16 for ionotropic receptors (IRs), and 6 for gustatory receptors (GRs). The numbers are similar to those of other Diptera species, suggesting that we were able to successfully identify S. pyrastri chemosensory genes. We analyzed the expression patterns of all genes by using reverse transcriptase PCR (RT-PCR), and found that some genes exhibited sex-biased or sex-specific expression. These candidate chemosensory genes and their tissue expression profiles provide information for further studies aimed at fully understanding the molecular basis behind chemoreception-related behaviors in S. pyrastri. PMID:27171401

  4. Assessment of association of D3 dopamine receptor MscI polymorphism with schizophrenia: Analysis of symptom ratings, family history, age at onset, and movement disorders

    SciTech Connect

    Gaitonde, E.J.; Mollon, J.D.; McKenna, P.J.

    1996-09-20

    Several studies have reported an association between schizophrenia and homozygosity for the MscI restriction site in exon 1 of the D3 dopamine receptor gene, but other studies have failed to find this association. Recent reports have suggested that the association is most salient in male patients with a family history of schizophrenia. We examined this restriction site in a group of schizophrenic patients (n = 84) and in normal controls (n = 77). Patients were subdivided according to demographic and clinical features, particular attention being paid to movement disorders. No significant difference in allelic or genotypic distribution was seen between the two groups. No association was seen between homozygosity and a positive family history, age at onset of illness, clinical subtype, negative symptom score, or movement disorder scores. 33 refs., 2 tabs.

  5. Expression of receptors for glial cell line-derived neurotrophic factor family ligands in sacral spinal cord reveals separate targets of pelvic afferent fibers.

    PubMed

    Forrest, Shelley L; Keast, Janet R

    2008-02-20

    Nerve growth factor has been proposed to mediate many structural and chemical changes in bladder sensory neurons after injury or inflammation. We have examined the expression of receptors for the glial cell line-derived neurotrophic factor (GDNF) family within sensory terminals located in the sacral spinal cord and in bladder-projecting sacral dorsal root ganglion neurons of adult female Sprague-Dawley rats. Nerve fibers immunolabelled for GFRalpha1 (GDNF receptor), GFRalpha2 (neurturin receptor), or GFRalpha3 (artemin receptor) showed distinct distribution patterns in the spinal cord, suggesting separate populations of sensory fibers with different functions: GFRalpha1-labeled fibers were in outer lamina II and the lateral-collateral pathway and associated with autonomic interneurons and preganglionic neurons; GFRalpha2-labeled fibers were only in inner lamina II; GFRalpha3-labeled fibers were in lamina I, the lateral-collateral pathway, and areas surrounding dorsal groups of preganglionic neurons and associated interneurons. Immunofluorescence studies of retrogradely labelled bladder-projecting neurons in sacral dorsal root ganglia showed that approximately 25% expressed GFRalpha1 or GFRalpha3 immunoreactivity, the preferred receptors for GDNF and artemin, respectively. After cyclophosphamide-induced bladder inflammation, fluorescence intensity of GFRalpha1-positive fibers increased within the dorsal horn, but there was no change in the GFRalpha2- or GFRalpha3-positive fibers. These studies have shown that GDNF and artemin may target bladder sensory neurons and potentially mediate plasticity of sacral visceral afferent neurons following inflammation. Our results have also revealed three distinct subpopulations of sensory fibers within the sacral spinal cord, which have not been identified previously using other markers.

  6. Molecular analysis of exons 8, 9 and 10 of the fibroblast growth factor receptor 2 (FGFR2) gene in two families with index cases of Apert Syndrome

    PubMed Central

    Hernández, Gualberto; Barrera, Alejandro; Ospina, Sandra; Prada, Rolando

    2015-01-01

    Introduction: Apert syndrome (AS) is a craniosynostosis condition caused by mutations in the Fibroblast Growth Factor Receptor 2 (FGFR2) gene. Clinical features include cutaneous and osseous symmetric syndactily in hands and feet, with variable presentations in bones, brain, skin and other internal organs. Methods: Members of two families with an index case of Apert Syndrome were assessed to describe relevant clinical features and molecular analysis (sequencing and amplification) of exons 8, 9 and 10 of FGFR2 gen. Results: Family 1 consists of the mother, the index case and half -brother who has a cleft lip and palate. In this family we found a single FGFR2 mutation, S252W, in the sequence of exon 8. Although mutations were not found in the study of the patient affected with cleft lip and palate, it is known that these diseases share signaling pathways, allowing suspected alterations in shared genes. In the patient of family 2, we found a sequence variant T78.501A located near the splicing site, which could interfere in this process, and consequently with the protein function. PMID:26600631

  7. Change Detection of Lake Aba Samuel in Ethiopia

    NASA Astrophysics Data System (ADS)

    Kaczynski, R.; Rylko, A.

    2016-06-01

    Old topographic map published in 1975 elaborated from aerial photographs taken in 1972, Landsat TM data acquired in May 1986 and Landsat ETM+ from June 2002 have been used to assess the changes of the lake Aba Samuel in Ethiopia. First map of the lake has been done in the framework of UNDP project running in 1988-90 in the Ethiopian Mapping Authority. The second classification map has been done as M.Sc. thesis in the MUT in 2015. Supervised classification methods with the use of ground truth data have been used for elaboration of the Landsat TM data. From the year 1972 up to 1986 the area of the lake has decreased by 23%. From 1986 up to 2002 the area of the lake has decreased by 20%. Therefore, after 30 years the lake was smaller by 43%. This have had very bad influence on the lives of the local population. From other recent data in the period from 2002-2015 the lake has practically disappeared and now it is only a small part of the river Akaki. ENVI 5.2 and ERDAS IMAGINE 9.2 have been used for Radiometric Calibration, Quick Atmospheric Correction (QUAC) and supervised classification of Landsat ETM+ data. The Optimum Index Factor shows the best combination of Landsat TM and ETM+ bands for color composite as 1,4,5 in the color filters: B, G, R for the signature development. Methodology and final maps are enclosed in the paper.

  8. Imidazolium-Containing ABA Triblock Copolymers as Electroactive Devices.

    PubMed

    Margaretta, Evan; Fahs, Gregory B; Inglefield, David L; Jangu, Chainika; Wang, Dong; Heflin, James R; Moore, Robert B; Long, Timothy E

    2016-01-20

    Two-step reversible addition-fragmentation chain transfer (RAFT) polymerization and two subsequent postpolymerization modification steps afforded well-defined ABA triblock copolymers featuring mechanically reinforcing polystyrene outer blocks and 1-methylimidazole-neutralized poly(acrylic acid)-based central blocks. Size exclusion chromatography and (1)H NMR spectroscopy confirmed predictable molecular weights and narrow distributions. The ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIm][OTf]) was incorporated at 30 wt % into polymeric films. Thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis determined the thermomechanical properties of the polymers and polymer-IL composites. Atomic force microscopy, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) determined surface and bulk morphologies, and poly(Sty-b-AA(MeIm)-b-Sty) exhibited a change from packed cylindrical to lamellar morphology in SAXS upon IL incorporation. Electrochemical impedance spectroscopy determined the in-plane ionic conductivities of the polymer-IL membranes (σ ∼ 10(-4) S/cm). A device fabricated from poly(Sty-b-AA(MeIm)-b-Sty) with 30 wt % incorporated IL demonstrated mechanical actuation under a low applied voltage of 4 V. PMID:26699795

  9. Differences in phosphatidic acid signalling and metabolism between ABA and GA treatments of barley aleurone cells.

    PubMed

    Villasuso, Ana Laura; Di Palma, Maria A; Aveldaño, Marta; Pasquaré, Susana J; Racagni, Graciela; Giusto, Norma M; Machado, Estela E

    2013-04-01

    Phosphatidic acid (PA) is the common lipid product in abscisic acid (ABA) and gibberellic acid (GA) response. In this work we investigated the lipid metabolism in response to both hormones. We could detect an in vivo phospholipase D activity (PLD, EC 3.1.4.4). This PLD produced [(32)P]PA (phosphatidic acid) rapidly (minutes) in the presence of ABA, confirming PA involvement in signal transduction, and transiently, indicating rapid PA removal after generation. The presence of PA removal by phosphatidate phosphatase 1 and 2 isoforms (E.C. 3.1.3.4) was verified in isolated aleurone membranes in vitro, the former but not the latter being specifically responsive to the presence of GA or ABA. The in vitro DGPP phosphatase activity was not modified by short time incubation with GA or ABA while the in vitro PA kinase - that allows the production of 18:2-DGPP from 18:2-PA - is stimulated by ABA. The long term effects (24 h) of ABA or GA on lipid and fatty acid composition of aleurone layer cells were then investigated. An increase in PC and, to a lesser extent, in PE levels is the consequence of both hormone treatments. ABA, in aleurone layer cells, specifically activates a PLD whose product, PA, could be the substrate of PAP1 and/or PAK activities. Neither PLD nor PAK activation can be monitored by GA treatment. The increase in PAP1 activity monitored after ABA or GA treatment might participate in the increase in PC level observed after 24 h hormone incubation.

  10. G-protein coupling and nuclear translocation of the human abscisic acid receptor LANCL2

    PubMed Central

    Fresia, Chiara; Vigliarolo, Tiziana; Guida, Lucrezia; Booz, Valeria; Bruzzone, Santina; Sturla, Laura; Di Bona, Melody; Pesce, Mattia; Usai, Cesare; De Flora, Antonio; Zocchi, Elena

    2016-01-01

    Abscisic acid (ABA), a long known phytohormone, has been recently demonstrated to be present also in humans, where it targets cells of the innate immune response, mesenchymal and hemopoietic stem cells and cells involved in the regulation of systemic glucose homeostasis. LANCL2, a peripheral membrane protein, is the mammalian ABA receptor. We show that N-terminal glycine myristoylation causes LANCL2 localization to the plasmamembrane and to cytoplasmic membrane vesicles, where it interacts with the α subunit of a Gi protein and starts the ABA signaling pathway via activation of adenylate cyclase. Demyristoylation of LANCL2 by chemical or genetic means triggers its nuclear translocation. Nuclear enrichment of native LANCL2 is also induced by ABA treatment. Therefore human LANCL2 is a non-transmembrane G protein-coupled receptor susceptible to hormone-induced nuclear translocation. PMID:27222287

  11. Inspection of the Grapevine BURP Superfamily Highlights an Expansion of RD22 Genes with Distinctive Expression Features in Berry Development and ABA-Mediated Stress Responses

    PubMed Central

    Matus, José Tomás; Aquea, Felipe; Espinoza, Carmen; Vega, Andrea; Cavallini, Erika; Santo, Silvia Dal; Cañón, Paola; de la Guardia, Amparo Rodríguez-Hoces; Serrano, Jennifer; Tornielli, Giovanni Battista; Arce-Johnson, Patricio

    2014-01-01

    The RESPONSIVE TO DEHYDRATION 22 (RD22) gene is a molecular link between abscisic acid (ABA) signalling and abiotic stress responses. Its expression has been used as a reliable ABA early response marker. In Arabidopsis, the single copy RD22 gene possesses a BURP domain also located at the C-terminus of USP embryonic proteins and the beta subunit of polygalacturonases. In grapevine, a RD22 gene has been identified but putative paralogs are also found in the grape genome, possibly forming a large RD22 family in this species. In this work, we searched for annotations containing BURP domains in the Vitis vinifera genome. Nineteen proteins were defined by a comparative analysis between the two genome predictions and RNA-Seq data. These sequences were compared to other plant BURPs identified in previous genome surveys allowing us to reconceive group classifications based on phylogenetic relationships and protein motif occurrence. We observed a lineage-specific evolution of the RD22 family, with the biggest expansion in grapevine and poplar. In contrast, rice, sorghum and maize presented highly expanded monocot-specific groups. The Vitis RD22 group may have expanded from segmental duplications as most of its members are confined to a region in chromosome 4. The inspection of transcriptomic data revealed variable expression of BURP genes in vegetative and reproductive organs. Many genes were induced in specific tissues or by abiotic and biotic stresses. Three RD22 genes were further studied showing that they responded oppositely to ABA and to stress conditions. Our results show that the inclusion of RNA-Seq data is essential while describing gene families and improving gene annotations. Robust phylogenetic analyses including all BURP members from other sequenced species helped us redefine previous relationships that were erroneously established. This work provides additional evidence for RD22 genes serving as marker genes for different organs or stresses in grapevine. PMID

  12. Molecular characterization of an ABA insensitive 5 orthologue in Brassica oleracea.

    PubMed

    Zhou, Xiaona; Yuan, Feifei; Wang, Mengyao; Guo, Aiguang; Zhang, Yanfeng; Xie, Chang Gen

    2013-01-18

    ABI5 (ABA insensitive 5), a bZIP (Basic leucine zipper) transcription factor, has been shown to be a major mediator of plant ABA responses during seed germination. Although the molecular basis of ABI5-modulated processes has been well demonstrated in Arabidopsis thaliana, its identity and function in cabbage (Brassica oleracea var. capitata L.) remain elusive. Here, we describe our identification of BolABI5 (an ABI5 orthologue in B.oleracea) as a functional bZIP transcription factor in the modulation of plant ABA responses. Expression of BolABI5 was dramatically induced by drought stress and exogenous ABA. Heterogeneous expression of BolABI5 rescued the insensitive phenotype of Arabidopsis abi5-1 to ABA during seed germination. Subcellular localization and trans-activation assays revealed that BolABI5 was localized in the nucleus and possessed DNA binding and trans-activation activities. Deletion of the bZIP domain generated BolABI5ΔbZIP, which no longer localized exclusively in the nucleus and had almost no detectable DNA-binding or trans-activation activities. Overall, these results suggest that BolABI5 may function as ABI5 in the positive regulation of plant ABA responses. PMID:23246838

  13. Dihydrothiazolopyridone Derivatives as a Novel Family of Positive Allosteric Modulators of the Metabotropic Glutamate 5 (mGlu5) Receptor

    PubMed Central

    Bartolomé-Nebreda, José Manuel; Conde-Ceide, Susana; Delgado, Francisca; Iturrino, Laura; Pastor, Joaquín; Pena, Miguel Ángel; Trabanco, Andrés A.; Tresadern, Gary; Wassvik, Carola M.; Stauffer, Shaun R.; Jadhav, Satyawan; Gogi, Kiran; Vinson, Paige N.; Noetzel, Meredith J.; Days, Emily; Weaver, C. David; Lindsley, Craig W.; Niswender, Colleen M.; Jones, Carrie K.; Conn, P. Jeffrey; Rombouts, Frederik; Lavreysen, Hilde; Macdonald, Gregor J.; Mackie, Claire; Steckler, Thomas

    2014-01-01

    Starting from a singleton chromanone high throughput screening (HTS) hit, we describe a focused medicinal chemistry optimization effort leading to the identification of a novel series of phenoxymethyl-dihydrothiazolopyridone derivatives as selective positive allosteric modulators (PAMs) of the metabotropic glutamate 5 (mGlu5) receptor. These dihydrothiazolopyridones potentiate receptor responses in recombinant systems. In vitro and in vivo drug metabolism and pharmacokinetic (DMPK) evaluation allowed us to select compound 16a for its assessment in a preclinical animal screen of possible antipsychotic activity. 16a was able to reverse amphetamine-induced hyperlocomotion in rats in a dose-dependent manner without showing any significant motor impairment or overt neurological side effects at comparable doses. Evolution of our medicinal chemistry program, structure activity, and properties relationships (SAR and SPR) analysis as well as a detailed profile for optimized mGlu5 receptor PAM 16a are described. PMID:23947773

  14. Identification of a point mutation in growth factor repeat C of the low density lipoprotein-receptor gene in a patient with homozygous familial hypercholesterolemia

    SciTech Connect

    Soutar, A.K.; Knight, B.L.; Patel, D.D. )

    1989-06-01

    The coding region of the low density lipoprotein (LDL)-receptor gene from a patient (MM) with homozygous familial hypercholesterolemia (FH) has been sequenced from six overlapping 500-base-pair amplified fragments of the cDNA from cultured skin fibroblasts. Two separate single nucleotide base changes from the normal sequence were detected. The first involved substitution of guanine for adenine in the third position of the codon for amino acid residue Cys-27 and did not affect the protein sequence. The second mutation was substitution of thymine for cytosine in the DNA for the codon for amino acid residue 664, changing the codon from CCG (proline) to CTG (leucine) and introducing a new site for the restriction enzyme PstI. MM is a true homozygote with two identical genes, and the mutation cosegregated with clinically diagnosed FH in his family in which first cousin marriages occurred frequently. LDL receptors in MM's skin fibroblasts bind less LDL than normal and with reduced affinity. Thus this naturally occurring single point mutation affects both intracellular transport of the protein and ligand binding and occurs in growth factor-like repeat C, a region that has not previously been found to influence LDL binding.

  15. The C-terminal TPR domain of Tom70 defines a family of mitochondrial protein import receptors found only in animals and fungi.

    PubMed

    Chan, Nickie C; Likić, Vladimir A; Waller, Ross F; Mulhern, Terrence D; Lithgow, Trevor

    2006-05-12

    In fungi and animals the translocase in the outer mitochondrial membrane (TOM complex) consists of multiple components including the receptor subunit Tom70. Genome sequence analyses suggest no Tom70 receptor subunit exists in plants or protozoans, raising questions about its ancestry, function and the importance of its activity. Here we characterise the relationships within the Tom70 family of proteins. We find that in both fungi and animals, a conserved domain structure exists within the Tom70 family, with a transmembrane segment followed by 11 tetratricopeptide repeat motifs organised in three distinct domains. The C-terminal domain of Tom70 is highly conserved, and crucial for the import of hydrophobic substrate proteins, including those with and those without N-terminal presequences. Tom70 likely arose after fungi and animals diverged from other eukaryote lineages including plants, and subsequent gene duplication gave rise to a paralogue specific to the Saccharomyces group of yeasts. In animals and in fungi, Tom70 plays a fundamental role in the import of precursor proteins, by assisting relatively hydrophobic regions of substrate proteins into the translocation channel in the outer mitochondrial membrane. Proteins that function equivalently to Tom70 may have arisen independently in plants and protists.

  16. Deletion of the steroid-binding domain of the human androgen receptor gene in one family with complete androgen insensitivity syndrome: Evidence for further genetic heterogeneity in this syndrome

    SciTech Connect

    Brown, T.R.; Lubahn, D.B.; Wilson, E.M.; Joseph, D.R.; French, F.S.; Migeon, C.J. )

    1988-11-01

    The cloning of a cDNA for the human androgen receptor gene has resulted in the availability for cDNA probes that span various parts of the gene, including the entire steroid-binding domain and part of the DNA-binding domain, as well as part of the 5' region of the gene. The radiolabeled probes were used to screen for androgen receptor mutations on Southern blots prepared by restriction endonuclease digestion of genomic DNA from human subjects with complete androgen insensitivity syndrome (AIS). In this investigation, the authors considered only patients presenting complete AIS and with the androgen receptor (-) form as the most probably subjects to show a gene deletion. One subject from each of six unrelated families with the receptor (-) form of complete AIS and 10 normal subjects were studied. In the 10 normal subjects and in 5 of the 6 patients, identical DNA restriction fragment patterns were observed with EcoRI and BamHI. Analysis of other members of this family confirmed the apparent gene deletion. The data provide direct proof that complete AIS in some families can result from a deletion of the androgen receptor structural gene. However, other families do not demonstrate such a deletion, suggesting that point mutations may also result in the receptor (-) form of complete AIS, adding further to the genetic heterogeneity of this syndrome.

  17. Schizophrenia and the androgen receptor gene: Report of a sibship showing co-segregation with Reifenstein Syndrome but no evidence for linkage in 23 multiply affected families

    SciTech Connect

    Arranz, M.; Sharma, T.; Sham, P.; Kerwin, R.

    1995-10-09

    Crow et al. have reported excess sharing of alleles by male sibling pairs with schizophrenia, at a triplet repeat marker within the androgen receptor gene, indicating that mutations at or near this gene may be a risk factor for males. In this report, we describe a pair of male siblings concordant for both schizophrenia and Reifenstein syndrome, which is caused by a mutation in this gene. This provides support for the hypothesis that the androgen receptor may contribute to liability to develop schizophrenia. Because of this, we have examined a collection of 23 pedigrees multiply affected by schizophrenia for linkage to the androgen receptor. We have found no evidence for linkage by both the LOD score and affected sibling-pair methods, under a range of genetic models with a broad and narrow definition of phenotype, and when families with male-to-male transmission are excluded. However, because of the small number of informative male-male pairs in our sample, we cannot confirm or refute the excess allele sharing for males reported by Crow. 35 refs., 1 fig., 2 tabs.

  18. Melanocortin 4 receptor sequence variations are seldom a cause of human obesity: the Swedish Obese Subjects, the HERITAGE Family Study, and a Memphis cohort.

    PubMed

    Jacobson, Peter; Ukkola, Olavi; Rankinen, Tuomo; Snyder, Eric E; Leon, Arthur S; Rao, D C; Skinner, James S; Wilmore, Jack H; Lönn, Lars; Cowan, George S; Sjöström, Lars; Bouchard, Claude

    2002-10-01

    The prevalence of mutations within and in the flanking regions of the gene encoding the melanocortin 4 receptor was investigated in severely obese and normal-weight subjects from the Swedish Obese Subjects study, the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family study, and a Memphis cohort. A total of 433 white and 95 black subjects (94% females) were screened for mutations by direct sequencing. Three previously described missense variants and nine novel (three missense, six silent) variants were detected. None of them showed significant association with obesity or related phenotypes. In addition, two novel deletions were found in two heterozygous obese women: a -65_-64delTG mutation within the 5' noncoding region and a 171delC frameshift mutation predicted to result in a truncated nonfunctional receptor. No pathogenic mutations were found among obese blacks or nonobese controls. Furthermore, none of the null mutations found in other populations was present in this sample. In conclusion, our results do not support the prevailing notion that sequence variation in the melanocortin 4 receptor gene is a frequent cause of human obesity.

  19. Familial congenital hypothyroidism due to inactivating mutation of the thyrotropin receptor causing profound hypoplasia of the thyroid gland.

    PubMed Central

    Abramowicz, M J; Duprez, L; Parma, J; Vassart, G; Heinrichs, C

    1997-01-01

    Thyroid gland agenesis is the most common cause of congenital hypothyroidism and is usually sporadic. We investigated a brother and sister from consanguineous parents, ascertained through systematic newborn screening, and initially diagnosed with thyroid agenesis. Careful cervical ultrasonography in both patients revealed a very hypoplastic thyroid gland. By direct sequencing of the thyrotropin receptor gene, we identified the substitution of threonine in place of a highly conserved alanine at position 553, in the fourth predicted transmembrane domain. The mutation was found homozygous in the affected siblings, and heterozygous in both parents and two unaffected siblings. Functional analysis in transfected COS-7 cells showed that it resulted in extremely low expression at the cell surface as compared with the wild-type receptor, in spite of an apparently normal intracellular synthesis. The small amount of mutated receptor expressed at the surface of transfected cells bound thyrotropin with normal affinity and responded in terms of cAMP production, but the in vivo significance of these data from overexpressed receptor in transfected cells is unclear. Of note, blood thyroglobulin was unexpectedly elevated in the patients at the time of diagnosis, a finding that might prove useful in refining etiologies of congenital hypothyroidism. PMID:9185526

  20. Familial Isolated Pituitary Adenomas (FIPA) and the Pituitary Adenoma Predisposition due to Mutations in the Aryl Hydrocarbon Receptor Interacting Protein (AIP) Gene

    PubMed Central

    Aaltonen, Lauri A.; Daly, Adrian F.

    2013-01-01

    Pituitary adenomas are one of the most frequent intracranial tumors and occur with a prevalence of approximately 1:1000 in the developed world. Pituitary adenomas have a serious disease burden, and their management involves neurosurgery, biological therapies, and radiotherapy. Early diagnosis of pituitary tumors while they are smaller may help increase cure rates. Few genetic predictors of pituitary adenoma development exist. Recent years have seen two separate, complimentary advances in inherited pituitary tumor research. The clinical condition of familial isolated pituitary adenomas (FIPA) has been described, which encompasses the familial occurrence of isolated pituitary adenomas outside of the setting of syndromic conditions like multiple endocrine neoplasia type 1 and Carney complex. FIPA families comprise approximately 2% of pituitary adenomas and represent a clinical entity with homogeneous or heterogeneous pituitary adenoma types occurring within the same kindred. The aryl hydrocarbon receptor interacting protein (AIP) gene has been identified as causing a pituitary adenoma predisposition of variable penetrance that accounts for 20% of FIPA families. Germline AIP mutations have been shown to associate with the occurrence of large pituitary adenomas that occur at a young age, predominantly in children/adolescents and young adults. AIP mutations are usually associated with somatotropinomas, but prolactinomas, nonfunctioning pituitary adenomas, Cushing disease, and other infrequent clinical adenoma types can also occur. Gigantism is a particular feature of AIP mutations and occurs in more than one third of affected somatotropinoma patients. Study of pituitary adenoma patients with AIP mutations has demonstrated that these cases raise clinical challenges to successful treatment. Extensive research on the biology of AIP and new advances in mouse Aip knockout models demonstrate multiple pathways by which AIP may contribute to tumorigenesis. This review assesses