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Sample records for aba receptor family

  1. 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.

  2. Identification and characterization of the abscisic acid (ABA) receptor gene family and its expression in response to hormones in the rubber tree

    PubMed Central

    Guo, Dong; Zhou, Ying; Li, Hui-Liang; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

    2017-01-01

    Abscisic acid (ABA) is an essential phytohormone involved in diverse physiological processes. Although genome-wide analyses of the ABA receptor PYR/PYL/RCAR (PYL) protein/gene family have been performed in certain plant species, little is known about the ABA receptor protein/gene family in the rubber tree (Hevea brasiliensis). In this study, we identified 14 ABA receptor PYL proteins/genes (designated HbPYL1 through HbPYL14) in the most recent rubber tree genome. A phylogenetic tree was constructed, which demonstrated that HbPYLs can be divided into three subfamilies that correlate well with the corresponding Arabidopsis subfamilies. Eight HbPYLs are highly expressed in laticifers. Five of the eight genes are simultaneously regulated by ABA, jasmonic acid (JA) and ethylene (ET). The identification and characterization of HbPYLs should enable us to further understand the role of ABA signal in the rubber tree. PMID:28332623

  3. The ABA receptors -- we report you decide.

    PubMed

    McCourt, Peter; Creelman, Robert

    2008-10-01

    The plant hormone abscisic acid (ABA) has been implicated in a variety of physiological responses ranging from seed dormancy to stomatal conductance. Recently, three groups have reported the molecular identification of three disparate ABA receptors. Unlike the identification of other hormone receptors, in these three cases high affinity binding to ABA rather than the isolation of ABA insensitive mutants led to these receptor genes. Interestingly, two of the receptors encode genes involved in floral timing and chlorophyll biosynthesis, which are not considered traditional ABA responses. And the third receptor has been clouded in issues of its molecular identity. To clearly determine the roles of these genes in ABA perception it will require placing of these ABA-binding proteins into the rich ABA physiological context that has built up over the years.

  4. 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.

  5. 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.

  6. Inactivation of PYR/PYL/RCAR ABA receptors by tyrosine nitration may enable rapid inhibition of ABA signaling by nitric oxide in plants.

    PubMed

    Castillo, Mari-Cruz; Lozano-Juste, Jorge; González-Guzmán, Miguel; Rodriguez, Lesia; Rodriguez, Pedro L; León, José

    2015-09-01

    Abscisic acid (ABA) is a phytohormone that inhibits growth and enhances adaptation to stress in plants. ABA perception and signaling rely on its binding to receptors of the pyrabactin resistance1/PYR1-like/regulatory components of ABA receptors (PYR/PYL/RCAR) family, the subsequent inhibition of clade A type 2C protein phosphatases (PP2Cs), and the phosphorylation of ion channels and transcription factors by protein kinases of the SnRK2 family. Nitric oxide (NO) may inhibit ABA signaling because NO-deficient plants are hypersensitive to ABA. Regulation by NO often involves posttranslational modification of proteins. Mass spectrometry analysis of ABA receptors expressed in plants and recombinant receptors modified in vitro revealed that the receptors were nitrated at tyrosine residues and S-nitrosylated at cysteine residues. In an in vitro ABA-induced, PP2C inhibition assay, tyrosine nitration reduced receptor activity, whereas S-nitrosylated receptors were fully capable of ABA-induced inhibition of the phosphatase. PYR/PYL/RCAR proteins with nitrated tyrosine, which is an irreversible covalent modification, were polyubiquitylated and underwent proteasome-mediated degradation. We propose that tyrosine nitration, which requires NO and superoxide anions, is a rapid mechanism by which NO limits ABA signaling under conditions in which NO and reactive oxygen species are both produced.

  7. Characterization of potential ABA receptors in Vitis vinifera.

    PubMed

    Boneh, Uri; Biton, Iris; Zheng, Chuanlin; Schwartz, Amnon; Ben-Ari, Giora

    2012-02-01

    Molecular control mechanisms for abiotic stress tolerance are based on the activation and regulation of specific stress-related genes. The phytohormone abscisic acid (ABA) is a key endogenous messenger in a plant's response to such stresses. A novel ABA binding mechanism which plays a key role in plant cell signaling cascades has recently been uncovered. In the absence of ABA, a type 2C protein phosphatase (PP2C) interacts and inhibits the kinase SnRK2. Binding of ABA to the PYR/PYLs receptors enables interaction between the ABA receptor and the PP2C protein, and abrogates the SnRK2 inactivation. The active SnRK2 is then free to activate the ABA-responsive element Binding Factors which target ABA-dependent gene expression. We used the grape as a model to study the ABA perception mechanism in fruit trees. The grape ABA signaling cascade consists of at least seven ABA receptors and six PP2Cs. We used a yeast two-hybrid system to examine physical interaction in vitro between the grape ABA receptors and their interacting partners, and found that twenty-two receptor-PP2C interactions can occur. Moreover, quantifying these affinities by the use of the LacZ reporter enables us to show that VvPP2C4 and VvPP2C9 are the major binding partners of the ABA receptor. We also tested in vivo the root and leaf gene expression of the various ABA receptors and PP2Cs in the presence of exogenic ABA and under different abiotic stresses such as high salt concentration, cold and drought, and found that many of these genes are regulated by such abiotic environmental factors. Our results indicate organ specificity in the ABA receptor genes and stress specificity in the VvPP2Cs. We suggest that VvPP2C4 is the major PP2C involved in ABA perception in leaves and roots, and VvRCAR6 and VvRCAR5 respectively, are the major receptors involved in ABA perception in these organs. Identification, characterization and manipulation of the central players in the ABA signaling cascades in fruit trees is

  8. Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance

    PubMed Central

    Okamoto, Masanori; Peterson, Francis C.; Defries, Andrew; Park, Sang-Youl; Endo, Akira; Nambara, Eiji; Volkman, Brian F.; Cutler, Sean R.

    2013-01-01

    Abscisic acid (ABA) is an essential molecule in plant abiotic stress responses. It binds to soluble pyrabactin resistance1/PYR1-like/regulatory component of ABA receptor receptors and stabilizes them in a conformation that inhibits clade A type II C protein phosphatases; this leads to downstream SnRK2 kinase activation and numerous cellular outputs. We previously described the synthetic naphthalene sulfonamide ABA agonist pyrabactin, which activates seed ABA responses but fails to trigger substantial responses in vegetative tissues in Arabidopsis thaliana. Here we describe quinabactin, a sulfonamide ABA agonist that preferentially activates dimeric ABA receptors and possesses ABA-like potency in vivo. In Arabidopsis, the transcriptional responses induced by quinabactin are highly correlated with those induced by ABA treatments. Quinabactin treatments elicit guard cell closure, suppress water loss, and promote drought tolerance in adult Arabidopsis and soybean plants. The effects of quinabactin are sufficiently similar to those of ABA that it is able to rescue multiple phenotypes observed in the ABA-deficient mutant aba2. Genetic analyses show that quinabactin’s effects in vegetative tissues are primarily mediated by dimeric ABA receptors. A PYL2-quinabactin-HAB1 X-ray crystal structure solved at 1.98-Å resolution shows that quinabactin forms a hydrogen bond with the receptor/PP2C “lock” hydrogen bond network, a structural feature absent in pyrabactin-receptor/PP2C complexes. Our results demonstrate that ABA receptors can be chemically controlled to enable plant protection against water stress and define the dimeric receptors as key targets for chemical modulation of vegetative ABA responses. PMID:23818638

  9. Activation of dimeric ABA receptors elicits guard cell closure, ABA-regulated gene expression, and drought tolerance.

    PubMed

    Okamoto, Masanori; Peterson, Francis C; Defries, Andrew; Park, Sang-Youl; Endo, Akira; Nambara, Eiji; Volkman, Brian F; Cutler, Sean R

    2013-07-16

    Abscisic acid (ABA) is an essential molecule in plant abiotic stress responses. It binds to soluble pyrabactin resistance1/PYR1-like/regulatory component of ABA receptor receptors and stabilizes them in a conformation that inhibits clade A type II C protein phosphatases; this leads to downstream SnRK2 kinase activation and numerous cellular outputs. We previously described the synthetic naphthalene sulfonamide ABA agonist pyrabactin, which activates seed ABA responses but fails to trigger substantial responses in vegetative tissues in Arabidopsis thaliana. Here we describe quinabactin, a sulfonamide ABA agonist that preferentially activates dimeric ABA receptors and possesses ABA-like potency in vivo. In Arabidopsis, the transcriptional responses induced by quinabactin are highly correlated with those induced by ABA treatments. Quinabactin treatments elicit guard cell closure, suppress water loss, and promote drought tolerance in adult Arabidopsis and soybean plants. The effects of quinabactin are sufficiently similar to those of ABA that it is able to rescue multiple phenotypes observed in the ABA-deficient mutant aba2. Genetic analyses show that quinabactin's effects in vegetative tissues are primarily mediated by dimeric ABA receptors. A PYL2-quinabactin-HAB1 X-ray crystal structure solved at 1.98-Å resolution shows that quinabactin forms a hydrogen bond with the receptor/PP2C "lock" hydrogen bond network, a structural feature absent in pyrabactin-receptor/PP2C complexes. Our results demonstrate that ABA receptors can be chemically controlled to enable plant protection against water stress and define the dimeric receptors as key targets for chemical modulation of vegetative ABA responses.

  10. 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.

  11. 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

  12. ESCRT-I Component VPS23A Affects ABA Signaling by Recognizing ABA Receptors for Endosomal Degradation.

    PubMed

    Yu, Feifei; Lou, Lijuan; Tian, Miaomiao; Li, Qingliang; Ding, Yanglin; Cao, Xiaoqiang; Wu, Yaorong; Belda-Palazon, Borja; Rodriguez, Pedro L; Yang, Shuhua; Xie, Qi

    2016-12-05

    Recent discovery of PYR/PYL/RCAR-type abscisic acid (ABA) receptors has become one of most significant advances in plant science in the past decade. In mammals, endosomal sorting acts as an important pathway to downregulate different types of receptors, but its role in plant hormone signaling is poorly understood. Here, we report that an ubiquitin E2-like protein, VPS23A, which is a key component of ESCRT-I, negatively regulates ABA signaling. VPS23A has epistatic relationship with PYR/PYL/RCAR-type ABA receptors and disruption of VPS23A enhanced the activity of key kinase OST1 in the ABA signaling pathway under ABA treatment. Moreover, VPS23A interacts with PYR1/PYLs and K63-linked diubiquitin, and PYL4 possesses K63-linked ubiquitinated modification in vivo. Further analysis revealed that VPS23A affects the subcellular localization of PYR1 and the stability of PYL4. Taken together, our results suggest that VPS23A affects PYR1/PYL4 via vacuole-mediated degradation, providing an advanced understanding of both the turnover of ABA receptors and ESCRTs in plant hormone signaling.

  13. Abscisic acid (ABA) receptors: light at the end of the tunnel

    PubMed Central

    McCormick, Sheila

    2010-01-01

    The plant hormone abscisic acid (ABA) plays a role in several aspects of plant growth and development. Understanding how this hormonal stimulus is sensed and transduced turned out to be one of the major tasks in the field of plant signaling. A series of recent papers proposed several different proteins that could receive the ABA signal and initiate the signaling cascade. The winner appears to be PYR/PYL/RCAR (PYrabactin Resistance/PYrabactin Resistance-Like/Regulatory Component of Abscisic acid Receptor) proteins, as crystal structures were recently published. The crystal structures support the idea that upon ABA binding to a PYR/PYL/RCAR protein, the activity of a phosphatase 2C, with known repressive activity on ABA signaling, is inhibited. PMID:20948817

  14. FYVE1/FREE1 Interacts with the PYL4 ABA Receptor and Mediates its Delivery to the Vacuolar Degradation Pathway.

    PubMed

    Belda-Palazon, Borja; Rodriguez, Lesia; Fernandez, Maria A; Castillo, Mari-Cruz; Anderson, Erin A; Gao, Caiji; González-Guzmán, Miguel; Peirats-Llobet, Marta; Zhao, Qiong; De Winne, Nancy; Gevaert, Kris; De Jaeger, Geert; Jiang, Liwen; Leon, Jose; Mullen, Robert T; Rodriguez, Pedro L

    2016-08-05

    Recently, we described the ubiquitylation of PYL4 and PYR1 by the RING E3 ubiquitin ligase RSL1 at the plasma membrane of Arabidopsis thaliana. This suggested that ubiquitylated ABA receptors might be targeted to the vacuolar degradation pathway because such ubiquitylation is usually an internalization signal for the endocytic route. Here, we show that FYVE1 (previously termed FREE1), a recently described component of the endosomal sorting complex required for transport (ESCRT) machinery, interacted with RSL1-receptor complexes and recruited PYL4 to endosomal compartments. Although the ESCRT pathway has been assumed to be reserved for integral membrane proteins, we show the involvement of this pathway in the degradation of ABA receptors, which can be associated with membranes but are not integral membrane proteins. Knock-down fyve1 alleles are hypersensitive to ABA, illustrating the biological relevance of the ESCRT pathway for the modulation of ABA signaling. In addition, fyve1 mutants are impaired in the targeting of ABA receptors for vacuolar degradation, leading to increased accumulation of PYL4 and an enhanced response to ABA. Pharmacological and genetic approaches revealed a dynamic turnover of ABA receptors from the plasma membrane to the endosomal/vacuolar degradation pathway, which was mediated by FYVE1 and was dependent on RSL1. This process involves clathrin-mediated endocytosis and trafficking of PYL4 through the ESCRT pathway, which helps to regulate the turnover of ABA receptors and attenuate ABA signaling.

  15. 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

  16. [The LDL receptor family].

    PubMed

    Meilinger, Melinda

    2002-12-29

    The members of the LDL receptor family are structurally related endocytic receptors. Our view on these receptors has considerably changed in recent years. Not only have new members of the family been identified, but also several interesting observations have been published concerning the biological function of these molecules. The LDL receptor family members are able to bind and internalize a plethora of ligands; as a consequence, they play important roles in diverse physiological processes. These receptors are key players in the lipoprotein metabolism, vitamin homeostasis, Ca2+ homeostasis, cell migration, and embryonic development. Until recently, LDL receptor family members were thought to be classic endocytic receptors that provide cells with metabolites on one hand, while regulating the concentration of their ligands in the extracellular fluids on the other hand. However, recent findings indicate that in addition to their cargo transport function, LDL receptor family members can act as signal transducers, playing important roles in the development of the central nervous system or the skeleton. Better understanding of physiological and pathophysiological functions of these molecules may open new avenues for the treatment or prevention of many disorders.

  17. 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.

  18. BnSIP1-1, a Trihelix Family Gene, Mediates Abiotic Stress Tolerance and ABA Signaling in Brassica napus

    PubMed Central

    Luo, Junling; Tang, Shaohua; Mei, Fengling; Peng, Xiaojue; Li, Jun; Li, Xiaofei; Yan, Xiaohong; Zeng, Xinhua; Liu, Fang; Wu, Yuhua; Wu, Gang

    2017-01-01

    The trihelix family genes have important functions in light-relevant and other developmental processes, but their roles in response to adverse environment are largely unclear. In this study, we identified a new gene, BnSIP1-1, which fell in the SIP1 (6b INTERACTING PROTEIN1) clade of the trihelix family with two trihelix DNA binding domains and a fourth amphipathic α-helix. BnSIP1-1 protein specifically targeted to the nucleus, and its expression can be induced by abscisic acid (ABA) and different stresses. Overexpression of BnSIP1-1 improved seed germination under osmotic pressure, salt, and ABA treatments. Moreover, BnSIP1-1 decreased the susceptibility of transgenic seedlings to osmotic pressure and ABA treatments, whereas there was no difference under salt stress between the transgenic and wild-type seedlings. ABA level in the transgenic seedlings leaves was higher than those in the control plants under normal condition. Under exogenous ABA treatment and mannitol stress, the accumulation of ABA in the transgenic plants was higher than that in the control plants; while under salt stress, the difference of ABA content before treatment was gradually smaller with the prolongation of salt treatment time, then after 24 h of treatment the ABA level was similar in transgenic and wild-type plants. The transcription levels of several general stress marker genes (BnRD29A, BnERD15, and BnLEA1) were higher in the transgenic plants than the wild-type plants, whereas salt-responsive genes (BnSOS1, BnNHX1, and BnHKT) were not significantly different or even reduced compared with the wild-type plants, which indicated that BnSIP1-1 specifically exerted different regulatory mechanisms on the osmotic- and salt-response pathways in seedling period. Overall, these findings suggested that BnSIP1-1 played roles in ABA synthesis and signaling, salt and osmotic stress response. To date, information about the involvement of the Brassica napus trihelix gene in abiotic response is scarce

  19. Nitric oxide modulates sensitivity to ABA

    PubMed Central

    Lozano-Juste, Jorge

    2010-01-01

    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 signalling components; both two aspects that deserve our present and future attention. PMID:20168082

  20. 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…

  1. The NAC family transcription factor OsNAP confers abiotic stress response through the ABA pathway.

    PubMed

    Chen, Xu; Wang, Yaofeng; Lv, Bo; Li, Jie; Luo, Liqiong; Lu, Songchong; Zhang, Xuan; Ma, Hong; Ming, Feng

    2014-03-01

    Plants respond to environmental stresses by altering gene expression, and several genes have been found to mediate stress-induced expression, but many additional factors are yet to be identified. OsNAP is a member of the NAC transcription factor family; it is localized in the nucleus, and shows transcriptional activator activity in yeast. Analysis of the OsNAP transcript levels in rice showed that this gene was significantly induced by ABA and abiotic stresses, including high salinity, drought and low temperature. Rice plants overexpressing OsNAP did not show growth retardation, but showed a significantly reduced rate of water loss, enhanced tolerance to high salinity, drought and low temperature at the vegetative stage, and improved yield under drought stress at the flowering stage. Microarray analysis of transgenic plants overexpressing OsNAP revealed that many stress-related genes were up-regulated, including OsPP2C06/OsABI2, OsPP2C09, OsPP2C68 and OsSalT, and some genes coding for stress-related transcription factors (OsDREB1A, OsMYB2, OsAP37 and OsAP59). Our data suggest that OsNAP functions as a transcriptional activator that plays a role in mediating abiotic stress responses in rice.

  2. The ABA signal transduction mechanism in commercial crops: learning from Arabidopsis.

    PubMed

    Ben-Ari, Giora

    2012-08-01

    The phytohormone abscisic acid (ABA) affects a wide range of stages of plant development as well as the plant's response to biotic and abiotic stresses. Manipulation of ABA signaling in commercial crops holds promising potential for improving crop yields. Several decades of research have been invested in attempts to identify the first components of the ABA signaling cascade. It was only in 2009, that two independent groups identified the PYR/PYL/RCAR protein family as the plant ABA receptor. This finding was followed by a surge of studies on ABA signal transduction, many of them using Arabidopsis as their model. The ABA signaling cascade was found to consist of a double-negative regulatory mechanism assembled from three protein families. These include the ABA receptors, the PP2C family of inhibitors, and the kinase family, SnRK2. It was found that ABA-bound PYR/RCARs inhibit PP2C activity, and that PP2Cs inactivate SnRK2s. Researchers today are examining how the elucidation of the ABA signaling cascade in Arabidopsis can be applied to improvements in commercial agriculture. In this article, we have attempted to review recent studies which address this issue. In it, we discuss various approaches useful in identifying the genetic and protein components involved. Finally, we suggest possible commercial applications of genetic manipulation of ABA signaling to improve crop yields.

  3. Abscisic acid (ABA) receptors: light at the end of the tunnel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The plant hormone abscisic acid (ABA) plays a role in several aspects of plant growth and development. Understanding how this hormonal stimulus is sensed and transduced turned out to be one of the major tasks in the field of plant signaling. A series of recent papers proposed several different prote...

  4. A DTX/MATE-type transporter facilitates abscisic acid efflux and modulates ABA sensitivity and drought tolerance in Arabidopsis.

    PubMed

    Zhang, Haiwen; Zhu, Huifen; Pan, Yajun; Yu, Yuexuan; Luan, Sheng; Li, Legong

    2014-10-01

    Abscisic acid (ABA) regulates numerous physiological and developmental processes in plants. Recent studies identify intracellular ABA receptors, implicating the transport of ABA across cell membranes as crucial for ABA sensing and response. Here, we report that a DTX/Multidrug and Toxic Compound Extrusion (MATE) family member in Arabidopsis thaliana, AtDTX50, functions as an ABA efflux transporter. When expressed heterologously in both an Escherichia coli strain and Xenopus oocyte cells, AtDTX50 was found to facilitate ABA efflux. Furthermore, dtx50 mutant mesophyll cells preloaded with ABA released less ABA compared with the wild-type (WT). The AtDTX50 gene was expressed mainly in the vascular tissues and guard cells and its expression was strongly up-regulated by exogenous ABA. The AtDTX50::GFP fusion protein was localized predominantly to the plasma membrane. The dtx50 mutant plants were observed to be more sensitive to ABA in growth inhibition. In addition, compared with the WT, dtx50 mutant plants were more tolerant to drought with lower stomatal conductance, consistent with its function as an ABA efflux carrier in guard cells.

  5. 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.

  6. 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.

  7. GsCBRLK, a calcium/calmodulin-binding receptor-like kinase, is a positive regulator of plant tolerance to salt and ABA stress.

    PubMed

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

    2010-05-01

    Calcium/calmodulin-dependent kinases play vital roles in protein phosphorylation in eukaryotes, yet little is known about the phosphorylation process of calcium/calmodulin-dependent protein kinase and its role in stress signal transduction in plants. A novel plant-specific calcium-dependent calmodulin-binding receptor-like kinase (GsCBRLK) has been isolated from Glycine soja. A subcellular localization study using GFP fusion protein indicated that GsCBRLK is localized in the plasma membrane. Binding assays demonstrated that calmodulin binds to GsCBRLK with an affinity of 25.9 nM in a calcium-dependent manner and the binding motif lies between amino acids 147 to169 within subdomain II of the kinase domain. GsCBRLK undergoes autophosphorylation and Myelin Basis Protein phosphorylation in the presence of calcium. It was also found that calcium/calmodulin positively regulates GsCBRLK kinase activity through direct interaction between the calmodulin-binding domain and calmodulin. So, it is likely that GsCBRLK responds to an environmental stimulus in two ways: by increasing the protein expression level and by regulating its kinase activity through the calcium/calmodulin complex. Furthermore, cold, salinity, drought, and ABA stress induce GsCBRLK gene transcripts. Over-expression of GsCBRLK in transgenic Arabidopsis resulted in enhanced plant tolerance to high salinity and ABA and increased the expression pattern of a number of stress gene markers in response to ABA and high salt. These results identify GsCBRLK as a molecular link between the stress- and ABA-induced calcium/calmodulin signal and gene expression in plant cells.

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

    PubMed

    Li, Zixing; Waadt, Rainer; Schroeder, Julian I

    2016-05-01

    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.

  9. Genome-wide identification and expression analysis of the CaNAC family members in chickpea during development, dehydration and ABA treatments.

    PubMed

    Ha, Chien Van; Esfahani, Maryam Nasr; Watanabe, Yasuko; Tran, Uyen Thi; Sulieman, Saad; Mochida, Keiichi; Nguyen, Dong Van; Tran, Lam-Son Phan

    2014-01-01

    The plant-specific NAC transcription factors (TFs) play important roles in regulation of diverse biological processes, including development, growth, cell division and responses to environmental stimuli. In this study, we identified the members of the NAC TF family of chickpea (Cicer arietinum) and assess their expression profiles during plant development and under dehydration and abscisic acid (ABA) treatments in a systematic manner. Seventy-one CaNAC genes were detected from the chickpea genome, including 8 membrane-bound members of which many might be involved in dehydration responses as judged from published literature. Phylogenetic analysis of the chickpea and well-known stress-related Arabidopsis and rice NACs enabled us to predict several putative stress-related CaNACs. By exploring available transcriptome data, we provided a comprehensive expression atlas of CaNACs in various tissues at different developmental stages. With the highest interest in dehydration responses, we examined the expression of the predicted stress-related and membrane-bound CaNACs in roots and leaves of chickpea seedlings, subjected to well-watered (control), dehydration and ABA treatments, using real-time quantitative PCR (RT-qPCR). Nine-teen of the 23 CaNACs examined were found to be dehydration-responsive in chickpea roots and/or leaves in either ABA-dependent or -independent pathway. Our results have provided a solid foundation for selection of promising tissue-specific and/or dehydration-responsive CaNAC candidates for detailed in planta functional analyses, leading to development of transgenic chickpea varieties with improved productivity under drought.

  10. 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

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

    PubMed

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

    2011-11-01

    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.

  12. Muscarinic receptor family interacting proteins: role in receptor function.

    PubMed

    Borroto-Escuela, Dasiel O; Correia, Patrícia A; Romero-Fernandez, Wilber; Narvaez, Manuel; Fuxe, Kjell; Ciruela, Francisco; Garriga, Pere

    2011-02-15

    G protein-coupled receptors constitute one of the most important families of membrane receptors through which cells respond to extracellular stimuli. Receptors of this superfamily likely function as signal transduction complexes. The identification and analysis of their components provide new insights into a better understanding of these receptors' function and regulation. We used tandem-affinity purification and mass spectrometry as a systematic approach to characterize multiprotein complexes in the acetylcholine muscarinic receptor subfamily. To overcome the limitations associated with membrane protein receptor solubilization with detergents, we developed a strategy in which receptors are co-expressed with a cytoplasmic minigene construct, encoding the third intracellular loop and the C-terminal tail tagged to the tandem-affinity-cassette of each receptor subtype. Numerous protein complexes were identified, including many new interactions in various signalling pathways. Systematic identification data set together with protein interactions reported in the literature revealed a high degree of connectivity. These allow the proposal, for the first time, of an outline of the muscarinic interactome as a network of protein complexes and a context for a more reasoned and informed approach to drug discovery and muscarinic receptor subtype specificities.

  13. Evolutionary Conservation of ABA Signaling for Stomatal Closure in Ferns.

    PubMed

    Cai, Shengguan; Chen, Guang; Wang, Yuanyuan; Huang, Yuqing; Marchant, Blaine; Wang, Yizhou; Yang, Qian; Dai, Fei; Hills, Adrian; Franks, Peter J; Nevo, Eviatar; Soltis, Doug; Soltis, Pamela; Sessa, Emily; Wolf, Paul G; Xue, Dawei; Zhang, Guoping; Pogson, Barry J; Blatt, Mike R; Chen, Zhong-Hua

    2017-02-23

    ABA-driven stomatal regulation reportedly evolved after the divergence of ferns, during the early evolution of seed plants approximately 360 Mya. This hypothesis is based on the observation that the stomata of certain fern species are unresponsive to ABA, but exhibit passive hydraulic control. However, ABA-induced stomatal closure was detected in some mosses and lycophytes. Here, we observed that a number of ABA signaling and membrane transporter protein families diversified over the evolutionary history of land plants. The aquatic ferns Azolla filiculoides and Salvinia cucullata have representatives of 23 families of proteins orthologous to those of Arabidopsis thaliana and all other land plant species studied. Phylogenetic analysis of the key ABA signaling proteins indicates an evolutionarily conserved stomatal response to ABA. Moreover, comparative transcriptomic analysis has identified a suite of ABA responsive genes that differentially expressed in a terrestrial fern species, Polystichum proliferum. These genes encode proteins associated with ABA biosynthesis, transport, reception, transcription, signaling, and ion and sugar transport, which fit the general ABA signaling pathway constructed from Arabidopsis thaliana and Hordeum vulgare. The retention of these key ABA-responsive genes could have had a profound effect on the adaptation of ferns to dry conditions. Furthermore, stomatal assays have shown the primary evidence for ABA-induced closure of stomata in two terrestrial fern species P. proliferum and Nephrolepis exaltata. In summary, we report new molecular and physiological evidence for the presence of active stomatal control in ferns.

  14. 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.

  15. 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

  16. ABA control of plant macroelement membrane transport systems in response to water deficit and high salinity.

    PubMed

    Osakabe, Yuriko; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

    2014-04-01

    Plant growth and productivity are adversely affected by various abiotic stressors and plants develop a wide range of adaptive mechanisms to cope with these adverse conditions, including adjustment of growth and development brought about by changes in stomatal activity. Membrane ion transport systems are involved in the maintenance of cellular homeostasis during exposure to stress and ion transport activity is regulated by phosphorylation/dephosphorylation networks that respond to stress conditions. The phytohormone abscisic acid (ABA), which is produced rapidly in response to drought and salinity stress, plays a critical role in the regulation of stress responses and induces a series of signaling cascades. ABA signaling involves an ABA receptor complex, consisting of an ABA receptor family, phosphatases and kinases: these proteins play a central role in regulating a variety of diverse responses to drought stress, including the activities of membrane-localized factors, such as ion transporters. In this review, recent research on signal transduction networks that regulate the function ofmembrane transport systems in response to stress, especially water deficit and high salinity, is summarized and discussed. The signal transduction networks covered in this review have central roles in mitigating the effect of stress by maintaining plant homeostasis through the control of membrane transport systems.

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

    PubMed

    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

    2016-01-19

    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 Ca(2+) 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 Ca(2+) 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 Ca(2+)-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 Ca(2+) 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 Ca(2+)-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.

  18. 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

  19. Inhibition of FUSCA3 degradation at high temperature is dependent on ABA signaling and is regulated by the ABA/GA ratio.

    PubMed

    Chiu, Rex Shun; Saleh, Yazan; Gazzarrini, Sonia

    2016-11-01

    During seed imbibition at supra-optimal temperature, an increase in the abscisic acid (ABA)/gibberellin (GA) ratio imposes secondary dormancy to prevent germination (thermoinhibition). FUSCA3 (FUS3), a positive regulator of seed dormancy, accumulates in seeds imbibed at high temperature and increases ABA levels to inhibit germination. Recently, we showed that ABA inhibits FUS3 degradation at high temperature, and that ABA and high temperature also inhibit the ubiquitin-proteasome system, by dampening both proteasome activity and protein polyubiquitination. Here, we investigated the role of ABA signaling components and the ABA antagonizing hormone, GA, in the regulation of FUS3 levels. We show that the ABA receptor mutant, pyl1-1, is less sensitive to ABA and thermoinhibition. In this mutant background, FUS3 degradation in vitro is faster. Similarly, GA alleviates thermoinhibition and also increases FUS3 degradation. These results indicate that inhibition of FUS3 degradation at high temperature is dependent on a high ABA/GA ratio and a functional ABA signaling pathway. Thus, FUS3 constitutes an important node in ABA-GA crosstalk during germination at supra-optimal temperature.

  20. 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.

  1. 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

  2. Molecular mimicry regulates ABA signaling by SnRK2 kinases and PP2C phosphatases.

    PubMed

    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

    2012-01-06

    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.

  3. Identification of a family of muscarinic acetylcholine receptor genes

    SciTech Connect

    Bonner, T.I.; Buckley, N.J.; Young, A.C.; Brann, M.R.

    1987-07-31

    Complementary DNAs for three different muscarinic acetylcholine receptors were isolated from a rat cerebral cortex library, and the cloned receptors were expressed in mammalian cells. Analysis of human and rat genomic clones indicates that there are at least four functional muscarinic receptor genes and that these genes lack introns in the coding sequence. This gene family provides a new basis for evaluating the diversity of muscarinic mechanisms in the nervous system.

  4. Complexing receptor pharmacology: modulation of family B G protein-coupled receptor function by RAMPs.

    PubMed

    Sexton, Patrick M; Morfis, Maria; Tilakaratne, Nanda; Hay, Debbie L; Udawela, Madhara; Christopoulos, George; Christopoulos, Arthur

    2006-07-01

    The most well-characterized subgroup of family B G protein-coupledreceptors (GPCRs) comprises receptors for peptide hormones, such as secretin, calcitonin (CT), glucagon, and vasoactive intestinal peptide (VIP). Recent data suggest that many of these receptors can interact with a novel family of GPCR accessory proteins termed receptor activity modifying proteins (RAMPs). RAMP interaction with receptors can lead to a variety of actions that include chaperoning of the receptor protein to the cell surface as is the case for the calcitonin receptor-like receptor (CLR) and the generation of novel receptor phenotypes. RAMP heterodimerization with the CLR and related CT receptor is required for the formation of specific CT gene-related peptide, adrenomedullin (AM) or amylin receptors. More recent work has revealed that the specific RAMP present in a heterodimer may modulate other functions such as receptor internalization and recycling and also the strength of activation of downstream signaling pathways. In this article we review our current state of knowledge of the consequence of RAMP interaction with family B GPCRs.

  5. 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

  6. Molecular basis of the core regulatory network in ABA responses: sensing, signaling and transport.

    PubMed

    Umezawa, Taishi; Nakashima, Kazuo; Miyakawa, Takuya; Kuromori, Takashi; Tanokura, Masaru; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2010-11-01

    ABA is a major phytohormone that regulates a broad range of plant traits and is especially important for adaptation to environmental conditions. Our understanding of the molecular basis of ABA responses in plants improved dramatically in 2009 and 2010, banner years for ABA research. There are three major components; PYR/PYL/ RCAR (an ABA receptor), type 2C protein phosphatase (PP2C; a negative regulator) and SNF1-related protein kinase 2 (SnRK2; a positive regulator), and they offer a double negative regulatory system, [PYR/PYL/RCAR-| PP2C-| SnRK2]. In the absence of ABA, PP2C inactivates SnRK2 by direct dephosphorylation. In response to environmental or developmental cues, ABA promotes the interaction of PYR/PYL/RCAR and PP2C, resulting in PP2C inhibition and SnRK2 activation. This signaling complex can work in both the nucleus and cytosol, as it has been shown that SnRK2 phosphorylates basic-domain leucine zipper (bZIP) transcription factors or membrane proteins. Several structural analyses of PYR/PYL/RCAR have provided the mechanistic basis for this 'core signaling' model, by elucidating the mechanism of ABA binding of receptors, or the 'gate-latch-lock' mechanism of interaction with PP2C in inhibiting activity. On the other hand, intercellular ABA transport had remained a major issue, as had intracellular ABA signaling. Recently, two plasma membrane-type ABC transporters were identified and shed light on the influx/efflux system of ABA, resolving how ABA is transported from cell to cell in plants. Our knowledge of ABA responses in plants has been greatly expanded from intracellular signaling to intercellular transport of ABA.

  7. The EGFR Family: Not So Prototypical Receptor Tyrosine Kinases

    PubMed Central

    Lemmon, Mark A.; Schlessinger, Joseph; Ferguson, Kathryn M.

    2014-01-01

    The epidermal growth factor receptor (EGFR) was among the first receptor tyrosine kinases (RTKs) for which ligand binding was studied and for which the importance of ligand-induced dimerization was established. As a result, EGFR and its relatives have frequently been termed “prototypical” RTKs. Many years of mechanistic studies, however, have revealed that—far from being prototypical—the EGFR family is quite unique. As we discuss in this review, the EGFR family uses a distinctive “receptor-mediated” dimerization mechanism, with ligand binding inducing a dramatic conformational change that exposes a dimerization arm. Intracellular kinase domain regulation in this family is also unique, being driven by allosteric changes induced by asymmetric dimer formation rather than the more typical activation-loop phosphorylation. EGFR family members also distinguish themselves from other RTKs in having an intracellular juxtamembrane (JM) domain that activates (rather than autoinhibits) the receptor and a very large carboxy-terminal tail that contains autophosphorylation sites and serves an autoregulatory function. We discuss recent advances in mechanistic aspects of all of these components of EGFR family members, attempting to integrate them into a view of how RTKs in this important class are regulated at the cell surface. PMID:24691965

  8. 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.

  9. Maturing of the nuclear receptor family.

    PubMed

    Lazar, Mitchell A

    2017-04-03

    Members of the nuclear receptor (NR) superfamily of ligand-regulated transcription factors play important roles in reproduction, development, and physiology. In humans, genetic mutations in NRs are causes of rare diseases, while hormones and drugs that target NRs are in widespread therapeutic use. The present issue of the JCI includes a series of Review articles focused on specific NRs and their wide range of biological functions. Here I reflect on the past, present, and potential future highlights of research on the NR superfamily.

  10. The epidermal growth factor receptor family: Biology driving targeted therapeutics

    PubMed Central

    Wieduwilt, M. J.; Moasser, M. M.

    2011-01-01

    The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in regulating cell proliferation, survival, differentiation and migration. The ErbB receptors carry out both redundant and restricted functions in mammalian development and in the maintenance of tissues in the adult mammal. Loss of regulation of the ErbB receptors underlies many human diseases, most notably cancer. Our understanding of the function and complex regulation of these receptors has fueled the development of targeted therapeutic agents for human malignancies in the last 15 years. Here we review the biology of ErbB receptors, including their structure, signaling, regulation, and roles in development and disease, then briefly touch on their increasing roles as targets for cancer therapy. PMID:18259690

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

    PubMed

    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.

  12. Negative regulation of ErbB family receptor tyrosine kinases.

    PubMed

    Sweeney, C; Carraway, K L

    2004-01-26

    Receptors of the EGF receptor or ErbB family of growth factor receptor tyrosine kinases are frequently overexpressed in a variety of solid tumours, and the aberrant activation of their tyrosine kinase activities is thought to contribute to tumour growth and progression. Much effort has been put into developing inhibitors of ErbB receptors, and both antibody and small-molecule approaches have exhibited clinical success. Recently, a number of endogenous negative regulatory proteins have been identified that suppress the signalling activity of ErbB receptors in cells. These include intracellular RING finger E3 ubiquitin ligases such as cbl and Nrdp1 that mediate ErbB receptor degradation, and may include a wide variety of secreted and transmembrane proteins that suppress receptor activation by growth factor ligands. It will be of interest to determine the extent to which tumour cells suppress these pathways to promote their progression, and whether restoration of endogenous receptor-negative regulatory pathways may be exploited for therapeutic benefit.

  13. 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)

  14. Receptor-like kinases from Arabidopsis form a monophyletic gene family related to animal receptor kinases

    PubMed Central

    Shiu, Shin-Han; Bleecker, Anthony B.

    2001-01-01

    Plant receptor-like kinases (RLKs) are proteins with a predicted signal sequence, single transmembrane region, and cytoplasmic kinase domain. Receptor-like kinases belong to a large gene family with at least 610 members that represent nearly 2.5% of Arabidopsis protein coding genes. We have categorized members of this family into subfamilies based on both the identity of the extracellular domains and the phylogenetic relationships between the kinase domains of subfamily members. Surprisingly, this structurally defined group of genes is monophyletic with respect to kinase domains when compared with the other eukaryotic kinase families. In an extended analysis, animal receptor kinases, Raf kinases, plant RLKs, and animal receptor tyrosine kinases form a well supported group sharing a common origin within the superfamily of serine/threonine/tyrosine kinases. Among animal kinase sequences, Drosophila Pelle and related cytoplasmic kinases fall within the plant RLK clade, which we now define as the RLK/Pelle family. A survey of expressed sequence tag records for land plants reveals that mosses, ferns, conifers, and flowering plants have similar percentages of expressed sequence tags representing RLK/Pelle homologs, suggesting that the size of this gene family may have been close to the present-day level before the diversification of land plant lineages. The distribution pattern of four RLK subfamilies on Arabidopsis chromosomes indicates that the expansion of this gene family is partly a consequence of duplication and reshuffling of the Arabidopsis genome and of the generation of tandem repeats. PMID:11526204

  15. Trace amine-associated receptor 1-Family archetype or iconoclast?

    PubMed

    Grandy, David K

    2007-12-01

    Interest has recently been rekindled in receptors that are activated by low molecular weight, noncatecholic, 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" (TA) beta-phenylethylamine (PEA), tyramine (TYR), octopamine (OCT), synephrine (SYN), and tryptamine (TRYP) is the direct result of 2 publications that appeared in 2001 describing the cloning of a novel G protein-coupled receptor (GPCR) referred to by their discoverers Borowsky et al. as TA1 and Bunzow et al. as TA receptor 1 (TAR1). When heterologously expressed in Xenopus laevis oocytes and various eukaryotic cell lines, recombinant rodent and human TAR dose-dependently couple to the stimulation of adenosine 3',5'-monophosphate (cAMP) production. Structure-activity profiling based on this functional response has revealed that in addition to the TA, other biologically active compounds containing a 2-carbon aliphatic side chain linking an amino group to at least 1 benzene ring are potent and efficacious TA receptor agonists with amphetamine (AMPH), methamphetamine, 3-iodothyronamine, thyronamine, and dopamine (DA) among the most notable. Almost 100 years after the search for TAR began, numerous TA1/TAR1-related sequences, now called TA-associated receptors (TAAR), 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 TAR, 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 GPCR. Only then will it be possible to establish whether TAAR1 is the family archetype or an iconoclast.

  16. 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

  17. 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.

  18. Catalytic mechanism and kinase interactions of ABA-signaling PP2C phosphatases.

    PubMed

    Zhou, X Edward; Soon, Fen-Fen; Ng, Ley-Moy; Kovach, Amanda; Suino-Powell, Kelly M; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H Eric; Melcher, Karsten

    2012-05-01

    Abscisic acid (ABA) is an essential hormone that controls plant growth, development and responses to abiotic stresses. ABA signaling is mediated by type 2C protein phosphatases (PP2Cs), including HAB1 and ABI2, which inhibit stress-activated SnRK2 kinases and whose activity is regulated by ABA and ABA receptors. Based on biochemical data and our previously determined crystal structures of ABI2 and the SnRK2.6-HAB1 complex, we present the catalytic mechanism of PP2C and provide new insight into PP2C-SnRK2 interactions and possible roles of other SnRK2 kinases in ABA signaling.

  19. 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

  20. The HAB1 PP2C is inhibited by ABA-dependent PYL10 interaction.

    PubMed

    Li, Juan; Shi, Chaowei; Sun, Demeng; He, Yao; Lai, Chaohua; Lv, Pei; Xiong, Ying; Zhang, Longhua; Wu, Fangming; Tian, Changlin

    2015-06-05

    PYL10 is a monomeric abscisic acid (ABA) receptor that inhibits protein phosphatase 2C (PP2C) activity in Arabidopsis thaliana. Previous studies reported that the PP2C phosphatase inhibition by PYL10 was ABA-independent. Here, systematic PYL10 biochemical studies demonstrated that PYL10 activity was ABA-dependent, and the previously reported studies was interfered by the presence of BSA in the commercial kit. To investigate dynamic mechanism of how ABA binding to PYL10 induces PP2C phosphatase inhibiting activity, solution NMR relaxation analysis of apo-PYL10 and PYL10/ABA were conducted following backbone resonance assignments. Reduced spectrum density mapping of the backbone relaxation data revealed that PYL10 was more flexible in ABA bound form than apo-PYL10, indicating an increased conformational entropy upon ligand binding. Moreover, to illustrate conformation exchanges of PYL10 upon ABA binding, NMR line shape analysis was performed with increasing concentrations of ABA, and the results indicated that PYL10 backbone conformational changes occur at different time scales.

  1. 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

  2. ABA-mediated transcriptional regulation in response to osmotic stress in plants.

    PubMed

    Fujita, Yasunari; Fujita, Miki; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2011-07-01

    The plant hormone abscisic acid (ABA) plays a pivotal role in a variety of developmental processes and adaptive stress responses to environmental stimuli in plants. Cellular dehydration during the seed maturation and vegetative growth stages induces an increase in endogenous ABA levels, which control many dehydration-responsive genes. In Arabidopsis plants, ABA regulates nearly 10% of the protein-coding genes, a much higher percentage than other plant hormones. Expression of the genes is mainly regulated by two different families of bZIP transcription factors (TFs), ABI5 in the seeds and AREB/ABFs in the vegetative stage, in an ABA-responsive-element (ABRE) dependent manner. The SnRK2-AREB/ABF pathway governs the majority of ABA-mediated ABRE-dependent gene expression in response to osmotic stress during the vegetative stage. In addition to osmotic stress, the circadian clock and light conditions also appear to participate in the regulation of ABA-mediated gene expression, likely conferring versatile tolerance and repressing growth under stress conditions. Moreover, various other TFs belonging to several classes, including AP2/ERF, MYB, NAC, and HD-ZF, have been reported to engage in ABA-mediated gene expression. This review mainly focuses on the transcriptional regulation of ABA-mediated gene expression in response to osmotic stress during the vegetative growth stage in Arabidopsis.

  3. The transient receptor potential family of ion channels.

    PubMed

    Nilius, Bernd; Owsianik, Grzegorz

    2011-01-01

    The transient receptor potential (TRP) multigene superfamily encodes integral membrane proteins that function as ion channels. Members of this family are conserved in yeast, invertebrates and vertebrates. The TRP family is subdivided into seven subfamilies: TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), TRPA (ankyrin) and TRPN (NOMPC-like); the latter is found only in invertebrates and fish. TRP ion channels are widely expressed in many different tissues and cell types, where they are involved in diverse physiological processes, such as sensation of different stimuli or ion homeostasis. Most TRPs are non-selective cation channels, only few are highly Ca2+ selective, some are even permeable for highly hydrated Mg2+ ions. This channel family shows a variety of gating mechanisms, with modes of activation ranging from ligand binding, voltage and changes in temperature to covalent modifications of nucleophilic residues. Activated TRP channels cause depolarization of the cellular membrane, which in turn activates voltage-dependent ion channels, resulting in a change of intracellular Ca2+ concentration; they serve as gatekeeper for transcellular transport of several cations (such as Ca2+ and Mg2+), and are required for the function of intracellular organelles (such as endosomes and lysosomes). Because of their function as intracellular Ca2+ release channels, they have an important regulatory role in cellular organelles. Mutations in several TRP genes have been implicated in diverse pathological states, including neurodegenerative disorders, skeletal dysplasia, kidney disorders and pain, and ongoing research may help find new therapies for treatments of related diseases.

  4. Fine specificity and molecular competition in SLAM family receptor signalling.

    PubMed

    Wilson, Timothy J; Garner, Lee I; Metcalfe, Clive; King, Elliott; Margraf, Stefanie; Brown, Marion H

    2014-01-01

    SLAM family receptors regulate activation and inhibition in immunity through recruitment of activating and inhibitory SH2 domain containing proteins to immunoreceptor tyrosine based switch motifs (ITSMs). Binding of the adaptors, SAP and EAT-2 to ITSMs in the cytoplasmic regions of SLAM family receptors is important for activation. We analysed the fine specificity of SLAM family receptor phosphorylated ITSMs and the conserved tyrosine motif in EAT-2 for SH2 domain containing signalling proteins. Consistent with the literature describing dependence of CRACC (SLAMF7) on EAT-2, CRACC bound EAT-2 (KD = 0.003 μM) with approximately 2 orders of magnitude greater affinity than SAP (KD = 0.44 μM). RNA interference in cytotoxicity assays in NK92 cells showed dependence of CRACC on SAP in addition to EAT-2, indicating selectivity of SAP and EAT-2 may depend on the relative concentrations of the two adaptors. The concentration of SAP was four fold higher than EAT-2 in NK92 cells. Compared with SAP, the significance of EAT-2 recruitment and its downstream effectors are not well characterised. We identified PLCγ1 and PLCγ2 as principal binding partners for the EAT-2 tail. Both PLCγ1 and PLCγ2 are functionally important for cytotoxicity in NK92 cells through CD244 (SLAMF4), NTB-A (SLAMF6) and CRACC. Comparison of the specificity of SH2 domains from activating and inhibitory signalling mediators revealed a hierarchy of affinities for CD244 (SLAMF4) ITSMs. While binding of phosphatase SH2 domains to individual ITSMs of CD244 was weak compared with SAP or EAT-2, binding of tandem SH2 domains of SHP-2 to longer peptides containing tandem phosphorylated ITSMs in human CD244 increased the affinity ten fold. The concentration of the tyrosine phosphatase, SHP-2 was in the order of a magnitude higher than the adaptors, SAP and EAT-2. These data demonstrate a mechanism for direct recruitment of phosphatases in inhibitory signalling by ITSMs, while explaining competitive

  5. 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

  6. Overexpression of Poplar Pyrabactin Resistance-Like Abscisic Acid Receptors Promotes Abscisic Acid Sensitivity and Drought Resistance in Transgenic Arabidopsis.

    PubMed

    Yu, Jingling; Yang, Lei; Liu, Xiaobing; Tang, Renjie; Wang, Yuan; Ge, Haiman; Wu, Mengting; Zhang, Jiang; Zhao, Fugeng; Luan, Sheng; Lan, Wenzhi

    2016-01-01

    Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA) is a phytohormone that positively regulates seed dormancy and drought resistance. The PYR1 (Pyrabactin Resistance 1)/ PYRL (PYR-Like)/ RCAR (Regulatory Component of ABA Receptor) (PYR/PYL/RCAR) ABA receptor family has been identified and widely characterized in Arabidopsis thaliana. However, their functions in poplars remain unknown. Here, we report that 2 of 14 PYR/PYL/RCAR orthologues in poplar (Populus trichocarpa) (PtPYRLs) function as a positive regulator of the ABA signal transduction pathway. The Arabidopsis transient expression and yeast two-hybrid assays showed the interaction among PtPYRL1 and PtPYRL5, a clade A protein phosphatase 2C, and a SnRK2, suggesting that a core signalling complex for ABA signaling pathway exists in poplars. Phenotypic analysis of PtPYRL1 and PtPYRL5 transgenic Arabidopsis showed that these two genes positively regulated the ABA responses during the seed germination. More importantly, the overexpression of PtPYRL1 and PtPYRL5 substantially improved ABA sensitivity and drought stress tolerance in transgenic plants. In summary, we comprehensively uncovered the properties of PtPYRL1 and PtPYRL5, which might be good target genes to genetically engineer drought-Resistant plants.

  7. Overexpression of Poplar Pyrabactin Resistance-Like Abscisic Acid Receptors Promotes Abscisic Acid Sensitivity and Drought Resistance in Transgenic Arabidopsis

    PubMed Central

    Liu, Xiaobing; Tang, Renjie; Wang, Yuan; Ge, Haiman; Wu, Mengting; Zhang, Jiang; Zhao, Fugeng; Luan, Sheng; Lan, Wenzhi

    2016-01-01

    Drought stress is an important environmental factor limiting productivity of plants, especially fast growing species with high water consumption like poplar. Abscisic acid (ABA) is a phytohormone that positively regulates seed dormancy and drought resistance. The PYR1 (Pyrabactin Resistance 1)/ PYRL (PYR-Like)/ RCAR (Regulatory Component of ABA Receptor) (PYR/PYL/RCAR) ABA receptor family has been identified and widely characterized in Arabidopsis thaliana. However, their functions in poplars remain unknown. Here, we report that 2 of 14 PYR/PYL/RCAR orthologues in poplar (Populus trichocarpa) (PtPYRLs) function as a positive regulator of the ABA signal transduction pathway. The Arabidopsis transient expression and yeast two-hybrid assays showed the interaction among PtPYRL1 and PtPYRL5, a clade A protein phosphatase 2C, and a SnRK2, suggesting that a core signalling complex for ABA signaling pathway exists in poplars. Phenotypic analysis of PtPYRL1 and PtPYRL5 transgenic Arabidopsis showed that these two genes positively regulated the ABA responses during the seed germination. More importantly, the overexpression of PtPYRL1 and PtPYRL5 substantially improved ABA sensitivity and drought stress tolerance in transgenic plants. In summary, we comprehensively uncovered the properties of PtPYRL1 and PtPYRL5, which might be good target genes to genetically engineer drought-Resistant plants. PMID:27992471

  8. Adhesion family of G protein-coupled receptors and cancer.

    PubMed

    Lin, Hsi-Hsien

    2012-01-01

    The adhesion-class G protein-coupled receptors (adhesion-GPCRs) constitute the second largest GPCR sub-family in humans. Adhesion-GPCRs are defined by the chimeric structure of an unusually large extracellular cell-adhesion domain and a GPCR-like seven-pass transmembrane domain. Adhesion-GPCRs are hence expected to display both cellular adhesion and signaling functions in many biological systems. Adhesion-GPCRs are normally expressed in the central nervous, immune, and reproductive systems in a cell type- or tissue-restricted fashion. However, aberrant expression of distinct adhesion-GPCR molecules has been identified in various human cancers with some of the receptors closely associated with cancer development. Tumor-associated adhesion-GPCRs are thought to involve in tumorigenesis by affecting the growth of tumor cells, angiogenesis, tumor cell migration, invasion and metastasis either positively or negatively. Furthermore, some adhesion-GPCRs are considered potential biomarkers for specific types of cancers. In this review article, the expressional characteristics and functional role of cancer-associated adhesion-GPCRs are discussed in depth.

  9. Characterization of lamprey IL-17 family members and their receptors

    PubMed Central

    Han, Qifeng; Das, Sabyasachi; Hirano, Masayuki; Holland, Stephen J.; McCurley, Nathanael; Guo, Peng; Rosenberg, Charles S.; Boehm, Thomas; Cooper, Max D.

    2015-01-01

    Interleukin-17 is an ancient cytokine implicated in a variety of immune defense reactions. We have indentified five members of the sea lamprey IL-17 family (IL-17D.1, IL-17D.2, IL-17E, IL-17B and IL-17C) and six IL-17 receptor genes (IL-17RA.1, IL-17RA.2, IL-17RA.3, IL-17RF, IL-17RE/RC and IL-17RD), determined their relationship with mammalian orthologues, and examined their expression patterns and potential interactions in order to explore their roles in innate and adaptive immunity. The most highly expressed IL-17 family member is IL-17D.1 (mammalian IL-17D like), which was found to be preferentially expressed by epithelial cells of skin, intestine and gills and by the two types of lamprey T-like cells. IL-17D.1 binding to recombinant IL-17RA.1 and to the surface of IL-17RA.1-expressing B-like cells and monocytes of lamprey larvae was demonstrated, and treatment of lamprey blood cells with recombinant IL-17D.1 protein enhanced transcription of genes expressed by the B-like cells. These findings suggest a potential role for IL-17 in coordinating the interactions between T-like cells and other cells of the adaptive and innate immune systems in jawless vertebrates. PMID:26491201

  10. A Comprehensive Proteomic Survey of ABA-Induced Protein Phosphorylation in Rice (Oryza sativa L.)

    PubMed Central

    Qiu, Jiehua; Hou, Yuxuan; Wang, Yifeng; Li, Zhiyong; Zhao, Juan; Tong, Xiaohong; Lin, Haiyan; Wei, Xiangjin; Ao, Hejun; Zhang, Jian

    2017-01-01

    abscisic acid (ABA) is a key phytohormone regulating plant development and stress response. The signal transduction of ABA largely relies on protein phosphorylation. However; little is known about the phosphorylation events occurring during ABA signaling in rice thus far. By employing a label-free; MS (Mass Spectrometry)-based phosphoproteomic approach; we identified 2271 phosphosites of young rice seedlings and their intensity dynamics in response to ABA; during which 1060 proteins were found to be differentially phosphorylated. Western-blot analysis verified the differential phosphorylation pattern of D1, SMG1 and SAPK9 as indicated by the MS result; suggesting the high reliability of our phosphoproteomic data. The DP (differentially phosphorylated) proteins are extensively involved in ABA as well as other hormone signaling pathways. It is suggested that ABA antagonistically regulates brassinosteroid (BR) signaling via inhibiting BR receptor activity. The result of this study not only expanded our knowledge of rice phosphoproteome, but also shed more light on the pattern of protein phosphorylation in ABA signaling. PMID:28054942

  11. Characterization of aryl hydrocarbon receptor interacting protein (AIP) mutations in familial isolated pituitary adenoma families.

    PubMed

    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

    2010-08-01

    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 beta-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.

  12. 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

  13. Evolution of an expanded mannose receptor gene family.

    PubMed

    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.

  14. Diverse systems for pheromone perception: multiple receptor families in two olfactory systems.

    PubMed

    Hagino-Yamagishi, Kimiko

    2008-12-01

    Traditionally, the olfactory epithelium is considered to recognize conventional odors, while the vomeronasal organ detects pheromones. However, recent advances suggest that vertebrate pheromones can also be detected by the olfactory epithelium. In the vomeronasal organ and the olfactory epithelium, structurally distinct multiple receptor families are expressed. In rodents, two of these receptor families, V1R and V2R, are expressed specifically in the vomeronasal organ and detect pheromones and pheromone candidates. A newly isolated trace amine-associated receptor detects some of the putative pheromones in the mouse olfactory epithelium. In addition, distinct second-messenger pathways and neural circuits are used for pheromone perception mediated by each receptor family. Furthermore, the function of these receptor families in these olfactory organs appears to differ among various vertebrate species. The systems for pheromone perception in vertebrates are far more complex than previously predicted.

  15. The low-density lipoprotein receptor gene family: a cellular Swiss army knife?

    PubMed

    Nykjaer, Anders; Willnow, Thomas E

    2002-06-01

    The low-density lipoprotein receptor gene family is an evolutionarily conserved group of cell-surface receptors produced by mammals and other organisms. Initially thought to be endocytic receptors that mediate the uptake of lipoproteins, recent findings have shown that these receptors have other roles in a range of cellular processes. Among other activities, members of this family act as signal transducers in neuronal migration processes, regulate synaptic plasticity or control vitamin homeostasis. Such multifunctionality is achieved by interaction with diverse cell-surface proteins including glycolipid-anchored receptors, G-protein-coupled receptors and ion channels. Here, we review the molecular interactions of this protein family with other cell-surface proteins that provide specificity and versatility - a versatility that may be reminiscent of a cellular Swiss army knife.

  16. 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.

  17. 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

  18. The receptor kinase family: primary structure of rhodopsin kinase reveals similarities to the beta-adrenergic receptor kinase.

    PubMed Central

    Lorenz, W; Inglese, J; Palczewski, K; Onorato, J J; Caron, M G; Lefkowitz, R J

    1991-01-01

    Light-dependent deactivation of rhodopsin as well as homologous desensitization of beta-adrenergic receptors involves receptor phosphorylation that is mediated by the highly specific protein kinases rhodopsin kinase (RK) and beta-adrenergic receptor kinase (beta ARK), respectively. We report here the cloning of a complementary DNA for RK. The deduced amino acid sequence shows a high degree of homology to beta ARK. In a phylogenetic tree constructed by comparing the catalytic domains of several protein kinases, RK and beta ARK are located on a branch close to, but separate from the cyclic nucleotide-dependent protein kinase and protein kinase C subfamilies. From the common structural features we conclude that both RK and beta ARK are members of a newly delineated gene family of guanine nucleotide-binding protein (G protein)-coupled receptor kinases that may function in diverse pathways to regulate the function of such receptors. Images PMID:1656454

  19. Complete Disruption of the Kainate Receptor Gene Family Results in Corticostriatal Dysfunction in Mice.

    PubMed

    Xu, Jian; Marshall, John J; Fernandes, Herman B; Nomura, Toshihiro; Copits, Bryan A; Procissi, Daniele; Mori, Susumu; Wang, Lei; Zhu, Yongling; Swanson, Geoffrey T; Contractor, Anis

    2017-02-21

    Kainate receptors are members of the glutamate receptor family that regulate synaptic function in the brain. They modulate synaptic transmission and the excitability of neurons; however, their contributions to neural circuits that underlie behavior are unclear. To understand the net impact of kainate receptor signaling, we generated knockout mice in which all five kainate receptor subunits were ablated (5ko). These mice displayed compulsive and perseverative behaviors, including over-grooming, as well as motor problems, indicative of alterations in striatal circuits. There were deficits in corticostriatal input to spiny projection neurons (SPNs) in the dorsal striatum and correlated reductions in spine density. The behavioral alterations were not present in mice only lacking the primary receptor subunit expressed in adult striatum (GluK2 KO), suggesting that signaling through multiple receptor types is required for proper striatal function. This demonstrates that alterations in striatal function dominate the behavioral phenotype in mice without kainate receptors.

  20. Neuronal localization of the 5-HT2 receptor family in the amygdaloid complex.

    PubMed

    Bombardi, Cristiano

    2014-01-01

    The amygdaloid complex (or amygdala), a heterogeneous structure located in the medial portion of the temporal lobe, is composed of deep, superficial, and "remaining" nuclei. This structure is involved in the generation of emotional behavior, in the formation of emotional memories and in the modulation of the consolidation of explicit memories for emotionally arousing events. The serotoninergic fibers originating in the dorsal and medial raphe nuclei are critically involved in amygdalar functions. Serotonin (5-hydroxytryptamine, 5-HT) regulates amygdalar activity through the activation of the 5-HT2 receptor family, which includes three receptor subtypes: 5-HT2A, 5-HT2B, and 5-HT2C. The distribution and the functional activity of the 5-HT2 receptor family has been studied more extensively than that of the 5-HT2A receptor subtypes, especially in the deep nuclei. In these nuclei, the 5-HT2A receptor is expressed on both pyramidal and non-pyramidal neurons, and could play a critical role in the formation of emotional memories. However, the exact role of the 5-HT2A receptor subtypes, as well as that of the 5-HT2B and 5-HT2C receptor subtypes, in the modulation of the amygdalar microcircuits requires additional study. The present review reports data concerning the distribution and the functional roles of the 5-HT2 receptor family in the amygdala.

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

    SciTech Connect

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

    1991-02-15

    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. The authors 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. They 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 {sup 45}Ca{sup 2+} efflux assays. These data establish the existence of an additional member of the FGFR family that they have named FGFR-3.

  2. Toll-like Receptors, Triggering Receptor Expressed on Myeloid Cells Family Members and Receptor for Advanced Glycation End-products in Allergic Airway Inflammation

    PubMed Central

    Hall, Sannette C.; Agrawal, Devendra K.

    2016-01-01

    Asthma is a chronic disorder of the airways characterized by cellular infiltration, airway hyper-responsive and airway inflammation. Innate immune cells are the first line of defense against endogenous and exogenous signals in the airways and as such possess a diverse array of pattern recognition receptors. Toll-like receptors are crucial sentinels which when activated, can either promote or ameliorate the inflammatory response in predisposed individuals. The recently discovered triggering receptor expressed on myeloid cells family members are emerging mediators of inflammation. These receptors are believed to modulate inflammatory responses by collaborating with classic PRRs. Endogenous signals like HMGB-1, signaling through the receptor for advanced glycation end products, also promotes inflammation, however, its contribution to inflammation in the airways is not well known. Here, we discuss the role of each receptor in airway inflammation and highlight potential synergistic mechanisms, which contribute to disease pathogenesis in allergic asthma. PMID:26678062

  3. 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.

  4. 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

  5. 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.

  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. Function of the HD-Zip I gene Oshox22 in ABA-mediated drought and salt tolerances in rice.

    PubMed

    Zhang, Shuxin; Haider, Imran; Kohlen, Wouter; Jiang, Li; Bouwmeester, Harro; Meijer, Annemarie H; Schluepmann, Henriette; Liu, Chun-Ming; Ouwerkerk, Pieter B F

    2012-12-01

    Oshox22 belongs to the homeodomain-leucine zipper (HD-Zip) family I of transcription factors, most of which have unknown functions. Here we show that the expression of Oshox22 is strongly induced by salt stress, abscisic acid (ABA), and polyethylene glycol treatment (PEG), and weakly by cold stress. Trans-activation assays in yeast and transient expression analyses in rice protoplasts demonstrated that Oshox22 is able to bind the CAAT(G/C)ATTG element and acts as a transcriptional activator that requires both the HD and Zip domains. Rice plants homozygous for a T-DNA insertion in the promoter region of Oshox22 showed reduced Oshox22 expression and ABA content, decreased sensitivity to ABA, and enhanced tolerance to drought and salt stresses at the seedling stage. In contrast, transgenic rice over-expressing Oshox22 showed increased sensitivity to ABA, increased ABA content, and decreased drought and salt tolerances. Based on these results, we conclude that Oshox22 affects ABA biosynthesis and regulates drought and salt responses through ABA-mediated signal transduction pathways.

  8. 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.

  9. 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.

  10. Expansion of the Receptor-Like Kinase/Pelle Gene Family and Receptor-Like Proteins in Arabidopsis1[w

    PubMed Central

    Shin-Han, Shiu; Bleecker, Anthony B.

    2003-01-01

    Receptor-like kinases (RLKs) are a family of transmembrane proteins with versatile N-terminal extracellular domains and C-terminal intracellular kinases. They control a wide range of physiological responses in plants and belong to one of the largest gene families in the Arabidopsis genome with more than 600 members. Interestingly, this gene family constitutes 60% of all kinases in Arabidopsis and accounts for nearly all transmembrane kinases in Arabidopsis. Analysis of four fungal, six metazoan, and two Plasmodium sp. genomes indicates that the family was represented in all but fungal genomes, indicating an ancient origin for the family with a more recent expansion only in the plant lineages. The RLK/Pelle family can be divided into several subfamilies based on three independent criteria: the phylogeny based on kinase domain sequences, the extracellular domain identities, and intron locations and phases. A large number of receptor-like proteins (RLPs) resembling the extracellular domains of RLKs are also found in the Arabidopsis genome. However, not all RLK subfamilies have corresponding RLPs. Several RLK/Pelle subfamilies have undergone differential expansions. More than 33% of the RLK/Pelle members are found in tandem clusters, substantially higher than the genome average. In addition, 470 of the RLK/Pelle family members are located within the segmentally duplicated regions in the Arabidopsis genome and 268 of them have a close relative in the corresponding regions. Therefore, tandem duplications and segmental/whole-genome duplications represent two of the major mechanisms for the expansion of the RLK/Pelle family in Arabidopsis. PMID:12805585

  11. A combined LDL receptor/LDL receptor adaptor protein 1 mutation as the cause for severe familial hypercholesterolemia.

    PubMed

    Soufi, Muhidien; Rust, Stephan; Walter, Michael; Schaefer, Juergen R

    2013-05-25

    Familial hypercholesterolemia (FH) results from impaired catabolism of plasma low density lipoproteins (LDL), thus leading to high cholesterol, atherosclerosis, and a high risk of premature myocardial infarction. FH is commonly caused by defects of the LDL receptor or its main ligand apoB, together mediating cellular uptake and clearance of plasma LDL. In some cases FH is inherited by mutations in the genes of PCSK9 and LDLRAP1 (ARH) in a dominant or recessive trait. The encoded proteins are required for LDL receptor stability and internalization within the LDLR pathway. To detect the underlying genetic defect in a family of Turkish descent showing unregular inheritance of severe FH, we screened the four candidate genes by denaturing gradient gel electrophoresis (DGGE) mutation analysis. We identified different combinatory mixtures of LDLR- and LDLRAP1-gene defects as the cause for severe familial hypercholesterolemia in this family. We also show for the first time that a heterozygous LDLR mutation combined with a homozygous LDLRAP1 mutation produces a more severe hypercholesterolemia phenotype in the same family than a homozygous LDLR mutation alone.

  12. Is the ABA concentration in the sap collected by pressurizing leaves relevant for analysing drought effects on stomata? Evidence from ABA-fed leaves of transgenic plants with modified capacities to synthesize ABA.

    PubMed

    Borel, Charlotte; Simonneau, Thierry

    2002-02-01

    Most studies on the role of ABA in the stomatal response of the whole plant to drought rely on a good estimate of ABA concentration in xylem sap. In this report, varying volumes of sap (V(sap)) were collected by pressurizing leaves cut from several lines of N. plumbaginifolia with modified capacities to synthesize ABA. Leaves were fed with solutions of known ABA concentration ([ABA](solution) from 0-500 micromol m(-3)) for 2-3 h before sap collection. ABA concentration in extruded sap ([ABA](sap)) was compared with [ABA](solution). In low-volume extracts (less than 0.35 mm(3) cm(-2) leaf area) collected from leaves of well-watered plants, [ABA](sap) was close to [ABA](solution). For all lines, [ABA](sap) decreased with increasing V(sap). The same dilution effect was observed for leaves pressurized just after sampling on droughted plants, suggesting, as for detached leaves fed with ABA, that [ABA](sap) in low-volume extracts approximated well with the concentration of ABA entering leaves still attached on droughted plants. However, ABA-fed leaves sampled from droughted plants yielded higher [ABA](sap) than ABA-fed leaves sampled from well-watered plants. [ABA](sap) was also increased, although very slightly, when leaves were preincubated in highly enriched ABA solution. This indicates that some leaf ABA contributed to the ABA concentration returned in the extruded sap. Consistently, [ABA](sap) in medium-volume extracts (0.35-0.65 mm(3) cm(-2) leaf area) was lower for leaves sampled on under-producing lines than on the wild type. Despite these distortions between [ABA](solution) and [ABA](sap) in medium-volume extracts, stomatal conductance of ABA-fed leaves closely correlated with [ABA](sap) with a similar relationship in all cases, whilst relationships with [ABA](solution) were more scattered.

  13. 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

  14. Multigene families of immunoglobulin domain-containing innate immune receptors in zebrafish: deciphering the differences

    PubMed Central

    Rodríguez-Nunez, Iván; Wcisel, Dustin J.; Litman, Gary W.; Yoder, Jeffrey A.

    2014-01-01

    Five large multigene families encoding innate-type immune receptors that are comprised of immunoglobulin domains have been identified in bony fish, of which four do not possess definable mammalian orthologs. The members of some of the multigene families exhibit unusually extensive patterns of divergence and the individual family members demonstrate marked variation in interspecific comparisons. As a group, the gene families reveal striking differences in domain type and content, mechanisms of intracellular signaling, basic structural features, haplotype and allelic variation and ligand binding. The potential functional roles of these innate immune receptors, their relationships to immune genes in higher vertebrate species and the basis for their adaptive evolution are of broad interest. Ongoing investigations are expected to provide new insight into alternative mechanisms of immunity. PMID:24548770

  15. 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.

  16. Ligand Activation of TAM Family Receptors-Implications for Tumor Biology and Therapeutic Response

    PubMed Central

    Davra, Viralkumar; Kimani, Stanley G.; Calianese, David; Birge, Raymond B.

    2016-01-01

    The TAM family of receptors (i.e., Tyro3, Axl, and Mertk), and their ligands Growth arrest specific factor 6 (Gas6) and Protein S (Pros1) contribute to several oncogenic processes, such as cell survival, invasion, migration, chemo-resistance, and metastasis, whereby expression often correlates with poor clinical outcomes. In recent years, there has been great interest in the study of TAM receptors in cancer, stemming both from their roles as oncogenic signaling receptors, as well as their roles in tumor immunology. As a result, several classes of TAM inhibitors that include small molecule tyrosine kinase inhibitors, monoclonal antibodies, decoy receptors, as well as novel strategies to target TAM ligands are being developed. This paper will review the biology of TAM receptors and their ligands with a focus on cancer, as well as evidence-based data for the continued pursuit of TAM/Gas6 inhibitors in clinical practice. PMID:27916840

  17. 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.

  18. Brassinosteroids modulate ABA-induced stomatal closure in Arabidopsis

    PubMed Central

    Ha, Yunmi; Shang, Yun; Nam, Kyoung Hee

    2016-01-01

    Stomatal movement in response to water availability is an important physiological process in the survival of land plants. The plant hormone abscisic acid (ABA) and brassinosteroids (BRs) regulate stomatal closure. The physiological functions of ABA and BRs, including germination, cell elongation and stomatal movement, are generally known to be antagonistic. Here, we investigated how BRs affect stomatal movement alone and in combination with ABA. We demonstrate that brassinoslide (BL), the most active BR, promotes stomatal closure in an ABA-independent manner. Interestingly, BL also inhibited ABA-induced stomatal closure when a high concentration of BL was added to ABA. Furthermore, we found that the induction of some genes for reactive oxygen species (ROS) generation by ABA (AtrbohD, NIA1 and NIA2) and subsequent ROS production were repressed by BL treatment. The BR signaling mutant bri1-301 failed to inhibit ABA-induced stomatal closure upon BL treatment. However, BRI1-overexpressing transgenic plants were hypersensitive to ABA during stomatal closure, and BL reversed ABA-induced stomatal closure more completely than in wild type plants. Taken together, these results suggest that BRs can positively and negatively modulate ABA-induced stomatal closure. Therefore, interactions between ABA and BR signaling are important for the regulation of stomatal closure. PMID:27856707

  19. Dynamic evolution of toll-like receptor multigene families in echinoderms.

    PubMed

    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

  20. The pyrokinin/ pheromone biosynthesis-activating neuropeptide (PBAN) family of peptides and their receptors in Insecta: evolutionary trace indicates potential receptor ligand-binding domains.

    PubMed

    Jurenka, R; Nusawardani, T

    2011-06-01

    The pyrokinin/pheromone biosynthesis-activating neuropeptide (PBAN) family of G-protein-coupled receptors and their ligands have been identified in various insects. Physiological functions of pyrokinin peptides include muscle contraction, whereas PBAN regulates, among other functions, pheromone production in moths which indicates the pleiotropic nature of these peptides. Based on the alignment of annotated genomic sequences, the pyrokinin/PBAN family of receptors have similarity with the corresponding structures of the capa or periviscerokinin receptors of insects and the neuromedin U receptors of vertebrates. In our study, evolutionary trace (ET) analysis on the insect receptor sequences was conducted to predict the putative ligand recognition and binding sites. The ET analysis of four class-specific receptors indicated several amino acid residues that are conserved in the transmembrane domains. The receptor extracellular domains exhibit several class-specific amino acid residues, which could indicate putative domains for activation of these receptors by ligand recognition and binding.

  1. 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.

  2. 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

  3. Molecular basis of association of receptor activity-modifying protein 3 with the family B G protein-coupled secretin receptor.

    PubMed

    Harikumar, Kaleeckal G; Simms, John; Christopoulos, George; Sexton, Patrick M; Miller, Laurence J

    2009-12-15

    The three receptor activity-modifying proteins (RAMPs) have been recognized as being important for the trafficking and function of a subset of family B G protein-coupled receptors, although the structural basis for this has not been well established. In the current work, we use morphological fluorescence techniques, bioluminescence resonance energy transfer, and bimolecular fluorescence complementation to demonstrate that the secretin receptor associates specifically with RAMP3, but not with RAMP1 or RAMP2. We use truncation constructs, peptide competition experiments, and chimeric secretin-GLP1 receptor constructs to establish that this association is structurally specific, dependent on the intramembranous region of the RAMP and TM6 and TM7 of this receptor. There were no observed changes in secretin-stimulated cAMP, intracellular calcium, ERK1/2 phosphorylation, or receptor internalization in receptor-bearing COS or CHO-K1 cells in the presence or absence of exogenous RAMP transfection, although the secretin receptor trafficks normally to the cell surface in these cells in a RAMP-independent manner, resulting in both free and RAMP-associated receptor on the cell surface. RAMP3 association with this receptor was shown to be capable of rescuing a receptor mutant (G241C) that is normally trapped intracellularly in the biosynthetic machinery. Similarly, secretin receptor expression had functional effects on adrenomedullin activity, with increasing secretin receptor expression competing for RAMP3 association with the calcitonin receptor-like receptor to yield a functional adrenomedullin receptor. These data provide important new insights into the structural basis for RAMP3 interaction with a family B G protein-coupled receptor, potentially providing a highly selective target for drug action. This may be representative of similar interactions between other members of this receptor family and RAMP proteins.

  4. Activation by SLAM Family Receptors Contributes to NK Cell Mediated "Missing-Self" Recognition.

    PubMed

    Alari-Pahissa, Elisenda; Grandclément, Camille; Jeevan-Raj, Beena; Leclercq, Georges; Veillette, André; Held, Werner

    2016-01-01

    Natural Killer (NK) cells attack normal hematopoietic cells that do not express inhibitory MHC class I (MHC-I) molecules, but the ligands that activate NK cells remain incompletely defined. Here we show that the expression of the Signaling Lymphocyte Activation Molecule (SLAM) family members CD48 and Ly9 (CD229) by MHC-I-deficient tumor cells significantly contributes to NK cell activation. When NK cells develop in the presence of T cells or B cells that lack inhibitory MHC-I but express activating CD48 and Ly9 ligands, the NK cells' ability to respond to MHC-I-deficient tumor cells is severely compromised. In this situation, NK cells express normal levels of the corresponding activation receptors 2B4 (CD244) and Ly9 but these receptors are non-functional. This provides a partial explanation for the tolerance of NK cells to MHC-I-deficient cells in vivo. Activating signaling via 2B4 is restored when MHC-I-deficient T cells are removed, indicating that interactions with MHC-I-deficient T cells dominantly, but not permanently, impair the function of the 2B4 NK cell activation receptor. These data identify an important role of SLAM family receptors for NK cell mediated "missing-self" reactivity and suggest that NK cell tolerance in MHC-I mosaic mice is in part explained by an acquired dysfunction of SLAM family receptors.

  5. 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.

  6. Wounding of potato tubers induces increases in ABA biosynthesis and catabolism and alters expression of ABA metabolic genes.

    PubMed

    Suttle, Jeffrey C; Lulai, Edward C; Huckle, Linda L; Neubauer, Jonathan D

    2013-04-15

    The effects of physical wounding on ABA biosynthesis and catabolism and expression of genes encoding key ABA metabolic enzymes were determined in potato tubers. An increase in ABA and ABA metabolite content was observed 48h after wounding and remained elevated through 96h. Wounding induced dramatic increases in the expression of the ABA metabolic genes encoding zeaxanthin epoxidase (ZEP), 9-cis-epoxycarotenoid dioxygenase (NCED), and ABA-8'-hydroxylase. Although the patterns of wound-induced expression of individual genes varied, increased gene expression was observed within 3h of wounding and remained elevated through 96h. An apparent correlation between expression of the gene encoding ZEP and the increase in ABA content suggested that the wound-induced increase in ABA biosynthesis was regulated by both substrate availability and increased NCED activity. Suppression of wound-induced jasmonic acid accumulation by rinsing the wounded tissue with water did not inhibit the subsequent increase in ABA content. Exogenous ethylene completely suppressed the wound-induced increase in ABA content and dramatically reduced wound-induced up-regulation of ABA metabolic genes. This study is the first to identify the molecular bases for increased ABA accumulation following physical trauma in potato tubers and highlights the complex physiological interactions between various wound-induced hormones.

  7. The gustatory receptor family in the silkworm moth Bombyx mori is characterized by a large expansion of a single lineage of putative bitter receptors.

    PubMed

    Wanner, K W; Robertson, H M

    2008-12-01

    The gustatory receptor (Gr) family of insect chemoreceptors includes receptors for sugars and bitter compounds, as well as cuticular hydrocarbons and odorants such as carbon dioxide. We have annotated a total of 65 Gr genes from the silkworm Bombyx mori genome. The Gr family in the silkworm moth includes putative carbon dioxide receptors and sugar receptors, as well as duplicated orthologues of the orphan DmGr43a receptor. Most prominent in this 65-gene family, however, is a single large expansion of 55 Grs that we propose are predominantly 'bitter' receptors involved in perception of the large variety of secondary plant chemicals that caterpillars and moths encounter. These Grs might therefore mediate food choice and avoidance as well as oviposition site preference.

  8. A novel mutation of the erythropoietin receptor gene associated with primary familial and congenital polycythaemia.

    PubMed

    O'Rourke, Kacey; Fairbairn, David J; Jackson, Kathryn A; Morris, Kirk L; Tey, Siok-Keen; Kennedy, Glen A

    2011-04-01

    Primary familial and congenital polycythaemia (PFCP) is a rare form of inherited erythrocytosis caused by heterozygous mutations in the erythropoietin receptor gene (EPOR). We present a novel mutation in the EPOR in a 15-year-old male who was referred to our clinic for investigation of a persistently elevated haemoglobin level. A significant family history of unexplained erythrocytosis spanning four generations of the patient's family was established. The family history was also significant for an apparent increased rate of cerebrovascular disease in individuals with erythrocytosis. The mutation detected in our patient resides in exon 8 of EPOR, similar to all other EPOR mutations responsible for PFCP. These mutations result in truncation of the cytoplasmic domain of the receptor and impair down-regulation of signalling via the erythropoietin receptor (EPOR). Clinical manifestations in published cases have varied widely and there is a paucity of firm recommendations regarding the management of affected patients. Given the strong family history of complications attributable to erythrocytosis we have recommended venesection with a haematocrit target of ≤0.45 for our patient.

  9. The cellular response to neuregulins is governed by complex interactions of the erbB receptor family.

    PubMed Central

    Riese, D J; van Raaij, T M; Plowman, G D; Andrews, G C; Stern, D F

    1995-01-01

    Deregulated signaling by the four members of the epidermal growth factor receptor tyrosine kinase family (erbB family) is implicated in the genesis or progression of human cancers. However, efforts to analyze signaling by these receptors have been hampered by the diversity of ligands and extensive interreceptor cross talk. We have expressed the four human erbB family receptors, singly and in pairwise combinations, in a pro-B-lymphocyte cell line (Ba/F3) and investigated the range of interactions activated by the epidermal growth factor homology domain of the agonist neuregulin beta. The results provide the first comprehensive analysis of the response of this receptor family to a single peptide agonist. This peptide induced complex patterns of receptor tyrosine phosphorylation and regulation of Ba/F3 cell survival and proliferation. These data demonstrate the existence of several previously undocumented receptor interactions driven by neuregulin. PMID:7565730

  10. 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

  11. Developmental Impact of a Familial GABAA Receptor Epilepsy Mutation

    PubMed Central

    Chiu, Cindy; Reid, Christopher A.; Tan, Heneu O.; Davies, Philip J.; Single, Frank N.; Koukoulas, Irene; Berkovic, Samuel F.; Tan, Seong-Seng; Sprengel, Rolf; Jones, Mathew V.; Petrou, Steven

    2013-01-01

    Objective A major goal of epilepsy research is to understand the molecular and functional basis of seizure genesis. A human GABAA γ2 gene mutation (R43Q) is associated with generalized epilepsy. Introduction of this mutation into a mouse by gene targeting recapitulates the human phenotype demonstrating a strong genotype to phenotype link. GABAA receptors play a role in the moment-to-moment control of brain function and also on the long-term wiring of the brain by directing neuronal development. Our objective was to determine whether developmental expression of the mutation alters seizure susceptibility later in life. Methods A tetracycline-based conditional model for activation of a hypomorphic Q43 disease allele was created and validated. Seizure susceptibility was assessed using the subcutaneous pentylenetetrazole model. Results Seizure susceptibility was significantly reduced in mice where the Q43 allele was suppressed during development. Interpretation These results demonstrate that a human epilepsy-causing mutation impacts network stability during a critical developmental period. These data suggest that identification of presymptomatic children may provide a window for therapeutic intervention before overt symptoms are observed, potentially altering the course of epileptogenesis. PMID:18825662

  12. CRDB: Database of Chemosensory Receptor Gene Families in Vertebrate

    PubMed Central

    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. PMID:22393364

  13. 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.

  14. 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

  15. 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

  16. Versatility in ligand recognition by LDL receptor family proteins: advances and frontiers.

    PubMed

    Blacklow, Stephen C

    2007-08-01

    Proteins of the low-density lipoprotein receptor family transport cholesterol-carrying particles into cells, clear protease-inhibitor complexes from the circulation, participate in biological signaling cascades, and even serve as viral receptors. These receptors utilize clusters of cysteine-rich LDL receptor type-A (LA) modules to bind many of their ligands. Recent structures show that these modules typically exhibit a characteristic binding mode to recognize their partners, relying primarily on electrostatic complementarity and avidity effects. The dominant contribution of electrostatic interactions with small interface areas in these complexes allows binding to be regulated by changes in pH via at least two distinct mechanisms. The structure of the subtilisin/kexin family protease PCSK9, a newly identified molecular partner of the LDLR also implicated in LDL-cholesterol homeostasis, also raises the possibility that the LDLR and its related family members may employ other strategies for pH-sensitive binding that have yet to be uncovered.

  17. Antigen receptor-induced B lymphocyte apoptosis mediated via a protease of the caspase family.

    PubMed

    Andjelic, S; Liou, H C

    1998-02-01

    An extensive body of data, in a variety of systems, denoted the caspase family of proteases as a key player in the execution of programmed cell death. This family consists of cysteine proteases that cleave after asparagine-containing motifs. It is well established that the caspases are essential for the apoptosis mediated by Fas (CD95) and TNF receptor p55, molecules that contain the "death domain" in the cytoplasmic tail. However, little is known about the mechanisms underlying the antigen receptor-mediated cell death in B lymphocytes, a process instrumental in negative selection of potentially autoreactive B cells. Here, we investigated the involvement of caspases in cell death triggered via the antigen receptor in B lymphocytes (BCR) by using specific inhibitors. Initially, we used a well-established cell line, CH31, which is a model of B cell tolerance, to demonstrate that these proteases indeed participate in the BCR-induced apoptotic pathway. Next, we confirmed the physiological relevance of the caspase-mediated cell death pathway in splenic B cell populations isolated ex vivo that were induced to undergo apoptosis by extensive cross-linking of their BCR. Most interestingly, our data demonstrated that caspases regulate not only the nuclear DNA fragmentation, but also the surface membrane phosphatidylserine translocation as well as the degradation of a specific nuclear substrate. Taken together, this report supports the hypothesis that regulation of the caspase family is crucial in controlling the life/death decision in B lymphocytes mediated by the antigen receptor signal transduction.

  18. Family History and Breast Cancer Hormone Receptor Status in a Spanish Cohort

    PubMed Central

    Chavez-Uribe, Elisabet; Rodriguez, Beatriz Fernandez; Muñoz, Catuxa Celeiro; Redondo, Carmen M.; Fernandez, Maite Peña; Dominguez, Alejandro Novo; Pereira, Carina Doris; Martínez, María Elena; García-Caballero, Tomás; Rodriguez, Máximo Fraga; Antúnez, José; Carracedo, Angel; Forteza-Vila, Jerónimo; Gago-Dominguez, Manuela

    2012-01-01

    Background Breast cancer is a heterogenous disease that impacts racial/ethnic groups differently. Differences in genetic composition, lifestyles, reproductive factors, or environmental exposures may contribute to the differential presentation of breast cancer among Hispanic women. Materials and Methods A population-based study was conducted in the city of Santiago de Compostela, Spain. A total of 645 women diagnosed with operable invasive breast cancer between 1992 and 2005 participated in the study. Data on demographics, breast cancer risk factors, and clinico-pathological characteristics of the tumors were collected. Hormone receptor negative tumors were compared with hormone receptor postive tumors on their clinico-pathological characteristics as well as risk factor profiles. Results Among the 645 breast cancer patients, 78% were estrogen receptor-positive (ER+) or progesterone receptor-positive (PR+), and 22% were ER−&PR−. Women with a family history of breast cancer were more likely to have ER−&PR− tumors than women without a family history (Odds ratio, 1.43; 95% confidence interval, 0.91–2.26). This association was limited to cancers diagnosed before age 50 (Odds ratio, 2.79; 95% confidence interval, 1.34–5.81). Conclusions An increased proportion of ER−&PR− breast cancer was observed among younger Spanish women with a family history of the disease. PMID:22238615

  19. 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

  20. Novel Bioluminescent Binding Assays for Ligand–Receptor Interaction Studies of the Fibroblast Growth Factor Family

    PubMed Central

    Song, Ge; Shao, Xiao-Xia; Wu, Qing-Ping; Xu, Zeng-Guang; Liu, Ya-Li; Guo, Zhan-Yun

    2016-01-01

    We recently developed novel bioluminescent binding assays for several protein/peptide hormones to study their interactions with receptors using the so far brightest NanoLuc reporter. To validate the novel bioluminescent binding assay using a variety of protein/peptide hormones, in the present work we applied it to the fibroblast growth factor (FGF) family using the prototype member FGF2 as an example. A fully active recombinant FGF2 retaining a unique exposed cysteine (Cys) residue was chemically conjugated with an engineered NanoLuc carrying a unique exposed Cys residue at the C-terminus via formation of an intermolecular disulfide linkage. The NanoLuc-conjugated FGF2 (FGF2-Luc) retained high binding affinity to the overexpressed FGFR1 and the endogenous FGF receptor with the calculated dissociation constants of 161 ± 21 pM (n = 3) and 25 ± 4 pM (n = 3), respectively. In competition binding assays using FGF2-Luc as a tracer, receptor-binding potencies of wild-type or mutant FGF2s were accurately quantified. Thus, FGF2-Luc represents a novel non-radioactive tracer for the quantitative measurement of ligand–receptor interactions in the FGF family. These data suggest that the novel bioluminescent binding assay can be applied to a variety of protein/peptide hormones for ligand–receptor interaction studies. PMID:27414797

  1. [Study of LDL receptors and response to lovastatin therapy in familial homozygotic hypercholesterolemia].

    PubMed

    Ausina Gómez, A; Gilsanz Peral, A; Montero Brens, C; Dalmau Serra, J

    1991-11-01

    This study shows the results obtained with lovastatin as a combined therapy with probucol and cholestyramine on the lipid profile of two patients with homozygous familial hypercholesterolemia. Both have been diagnosed according to the clinical and biochemical criteria (tipe IIa hypercholesterolemia) as well as by the cholesterol or low density lipoprotein (LDL-C) receptor analysis. After the initial probucol and cholestyramine treatment we observed a drop of total cholesterol (T-C) of 41.7% and 46% as well as LDL-C of 51.6% and 49.3% in both patients. Respectively when lovastatin were associated an additional drop of T-C of 23.7%, LDL-C of 23.2%, high-density lipoprotein cholesterol (HDL-C) of 22.4% and the apoprotein B (Apo B) of 37% were obtained in one patient (receptor-defective) but no change in the lipid profile were obtained in the other patient (receptor-negative). No adverse effects were observed with this drug. This drug could be of help as a combined therapy in the treatment of homozygous familial hypercholesterolemia, even though the treatment of choice is the LDL-plasma feresis and/or liver transplantation. We expound the difficulties relate to LDL receptor study in homocygous receptor-negative patients.

  2. 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

  3. 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

  4. ABA Inducible Rice Protein Phosphatase 2C Confers ABA Insensitivity and Abiotic Stress Tolerance in Arabidopsis

    PubMed Central

    Singh, Amarjeet; Jha, Saroj K.; Bagri, Jayram; Pandey, Girdhar K.

    2015-01-01

    Arabidopsis PP2C belonging to group A have been extensively worked out and known to negatively regulate ABA signaling. However, rice (Oryza sativa) orthologs of Arabidopsis group A PP2C are scarcely characterized functionally. We have identified a group A PP2C from rice (OsPP108), which is highly inducible under ABA, salt and drought stresses and localized predominantly in the nucleus. Genetic analysis revealed that Arabidopsis plants overexpressing OsPP108 are highly insensitive to ABA and tolerant to high salt and mannitol stresses during seed germination, root growth and overall seedling growth. At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants. Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance. Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively. Transgenic rice plants overexpressing this gene might provide an answer to the problem of low crop yield and productivity during adverse environmental conditions. PMID:25886365

  5. ABA inducible rice protein phosphatase 2C confers ABA insensitivity and abiotic stress tolerance in Arabidopsis.

    PubMed

    Singh, Amarjeet; Jha, Saroj K; Bagri, Jayram; Pandey, Girdhar K

    2015-01-01

    Arabidopsis PP2C belonging to group A have been extensively worked out and known to negatively regulate ABA signaling. However, rice (Oryza sativa) orthologs of Arabidopsis group A PP2C are scarcely characterized functionally. We have identified a group A PP2C from rice (OsPP108), which is highly inducible under ABA, salt and drought stresses and localized predominantly in the nucleus. Genetic analysis revealed that Arabidopsis plants overexpressing OsPP108 are highly insensitive to ABA and tolerant to high salt and mannitol stresses during seed germination, root growth and overall seedling growth. At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants. Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance. Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively. Transgenic rice plants overexpressing this gene might provide an answer to the problem of low crop yield and productivity during adverse environmental conditions.

  6. 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

  7. 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.

  8. The EGFR family of receptors sensitizes cancer cells towards UV light

    NASA Astrophysics Data System (ADS)

    Petersen, Steffen; Neves-Petersen, Maria Teresa; Olsen, Birgitte

    2008-02-01

    A combination of bioinformatics, biophysical, advanced laser studies and cell biology lead to the realization that laser-pulsed UV light stops cancer growth and induces apoptosis. We have previously shown that laser-pulsed UV (LP-UV) illumination of two different skin-derived cancer cell lines both over expressing the EGF receptor, lead to arrest of the EGFR signaling pathway. We have investigated the available sequence and experimental 3D structures available in the Protein Data Bank. The EGF receptor contains a Furin like cystein rich extracellular domain. The cystein content is highly unusual, 25 disulphide bridges supports the 621 amino acid extracellular protein domain scaffold (1mb6.pdb). In two cases a tryptophan is neighboring a cystein in the primary sequence, which in itself is a rare observation. Aromatic residues is observed to be spatially close to all observed 25 disulphide bridges. The EGF receptor is often overexpressed in cancers and other proliferative skin disorders, it might be possible to significantly reduce the proliferative potential of these cells making them good targets for laser-pulsed UV-light treatment. The discovery that UV light can be used to open disulphide bridges in proteins upon illumination of nearby aromatic amino acids was the first step that lead to the hypothesis that UV light could modulate the structure and therefore the function of these key receptor proteins. The observation that membrane receptors (EGFR) contained exactly the motifs that are sensitive to UV light lead to the prediction that UV light could modify these receptors permanently and stop cancer proliferation. We hereby show that the EGFR family of receptors has the necessary structural motifs that make this family of proteins highly sensitive to UV light.

  9. Familial isolated pituitary adenomas (FIPA) and mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene.

    PubMed

    Daly, Adrian F; Beckers, Albert

    2015-03-01

    The most frequent conditions that are associated with inherited/familial pituitary adenomas are familial isolated pituitary adenoma (FIPA) and multiple endocrine neoplasia type 1 (MEN1), which together account for up to 5% of pituitary adenomas. One important genetic cause of FIPA are inactivating mutations or deletions in the aryl hydrocarbon receptor interacting protein (AIP) gene. FIPA is the most frequent clinical presentation of AIP mutations. This article traces the current state of knowledge regarding the clinical features of FIPA and the particular genetic, pathologic, and clinical characteristics of pituitary adenomas due to AIP mutations.

  10. Genomic organization of the mouse T-cell receptor beta-chain gene family.

    PubMed Central

    Lai, E; Barth, R K; Hood, L

    1987-01-01

    We have combined three different methods, deletion mapping of T-cell lines, field-inversion gel electrophoresis, and the restriction mapping of a cosmid clone, to construct a physical map of the murine T-cell receptor beta-chain gene family. We have mapped 19 variable (V beta) gene segments and the two clusters of diversity (D beta) and joining (J beta) gene segments and constant (C beta) genes. These members of the beta-chain gene family span approximately equal to 450 kilobases of DNA, excluding one potential gap in the DNA fragment alignments. Images PMID:3035555

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Activin receptor-like kinases: a diverse family playing an important role in cancer

    PubMed Central

    Loomans, Holli A; Andl, Claudia D

    2016-01-01

    The role and function of the members of the TGFβ superfamily has been a substantial area of research focus for the last several decades. During that time, it has become apparent that aberrations in TGFβ family signaling, whether through the BMP, Activin, or TGFβ arms of the pathway, can result in tumorigenesis or contribute to its progression. Downstream signaling regulates cellular growth under normal physiological conditions yet induces diverse processes during carcinogenesis, ranging from epithelial- to-mesenchymal transition to cell migration and invasion to angiogenesis. Due to these observations, the question has been raised how to utilize and target components of these signaling pathways in cancer therapy. Given that these cascades include both ligands and receptors, there are multiple levels at which to interfere. Activin receptor-like kinases (ALKs) are a group of seven type I receptors responsible for TGFβ family signal transduction and are utilized by many ligands within the superfamily. The challenge lies in specifically targeting the often-overlapping functional effects of BMP, Activin, or TGFβ signaling during cancer progression. This review focuses on the characteristic function of the individual receptors within each subfamily and their recognized roles in cancer. We next explore the clinical utility of therapeutically targeting ALKs as some have shown partial responses in Phase I clinical trials but disappointing outcomes when used in Phase II studies. Finally, we discuss the challenges and future directions of this body of work. PMID:27904762

  19. 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

  20. 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.

  1. Sequence analysis of the non-recurring C-terminal domains shows that insect lipoprotein receptors constitute a distinct group of LDL receptor family members.

    PubMed

    Rodenburg, Kees W; Smolenaars, Marcel M W; Van Hoof, Dennis; Van der Horst, Dick J

    2006-04-01

    Lipoprotein-mediated delivery of lipids in mammals involves endocytic receptors of the low density lipoprotein (LDL) receptor (LDLR) family. In contrast, in insects, the lipoprotein, lipophorin (Lp), functions as a reusable lipid shuttle in lipid delivery, and these animals, therefore, were not supposed to use endocytic receptors. However, recent data indicate additional endocytic uptake of Lp, mediated by a Lp receptor (LpR) of the LDLR family. The two N-terminal domains of LDLR family members are involved in ligand binding and dissociation, respectively, and are composed of a mosaic of multiple repeats. The three C-terminal domains, viz., the optional O-linked glycosylation domain, the transmembrane domain, and the intracellular domain, are of a non-repetitive sequence. The present classification of newly discovered LDLR family members, including the LpRs, bears no relevance to physiological function. Therefore, as a novel approach, the C-terminal domains of LDLR family members across the entire animal kingdom were used to perform a sequence comparison analysis in combination with a phylogenetic tree analysis. The LpRs appeared to segregate into a specific group distinct from the groups encompassing the other family members, and each of the three C-terminal domains of the insect receptors is composed of unique set of sequence motifs. Based on conservation of sequence motifs and organization of these motifs in the domains, LpR resembles most the groups of the LDLRs, very low density lipoprotein (VLDL) receptors, and vitellogenin receptors. However, in sequence aspects in which LpR deviates from these three receptor groups, it most notably resembles LDLR-related protein-2, or megalin. These features might explain the functional differences disclosed between insect and mammalian lipoprotein receptors.

  2. Interaction mechanism of insulin-like peptide 5 with relaxin family peptide receptor 4.

    PubMed

    Hu, Meng-Jun; Wei, Dian; Shao, Xiao-Xia; Wang, Jia-Hui; Liu, Ya-Li; Xu, Zeng-Guang; Guo, Zhan-Yun

    2017-04-01

    Insulin-like peptide 5 (INSL5) is a gut peptide hormone belonging to the insulin/relaxin superfamily. It is implicated in the regulation of food intake and glucose homeostasis by activating relaxin family peptide receptor 4 (RXFP4). Previous studies have suggested that the B-chain is important for INSL5 activity against RXFP4. However, functionalities of the B-chain residues have not yet been systematically studied. In the present work, we conducted alanine-scanning mutagenesis of the B-chain residues of human INSL5 to obtain an overview of their contributions. Binding and activation assays of these INSL5 mutants with human RXFP4 identified two essential exposed B-chain C-terminal residues (B23Arg and B24Trp) and one important exposed central B-chain residue (B16Ile). These three determinant residues together with the C-terminal carboxylate moiety probably constitute a central receptor-binding patch that forms critical hydrophobic and electrostatic interactions with RXFP4 during INSL5 binding. Some other exposed residues, including B10Glu, B12Ile, B13Arg, B17Tyr, B21Ser, and B22Ser, made minor contributions to INSL5 function. These auxiliary residues are scattered around the edge of the central receptor-binding patch, and thus form a peripheral receptor-binding patch on the surface of INSL5. Our present work provides new insights into the interaction mechanism of INSL5 with its receptor RXFP4.

  3. 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

  4. Complex Determinants in Specific Members of the Mannose Receptor Family Govern Collagen Endocytosis*

    PubMed Central

    Jürgensen, Henrik J.; Johansson, Kristina; Madsen, Daniel H.; Porse, Astrid; Melander, Maria C.; Sørensen, Kristine R.; Nielsen, Christoffer; Bugge, Thomas H.; Behrendt, Niels; Engelholm, Lars H.

    2014-01-01

    Members of the well-conserved mannose receptor (MR) protein family have been functionally implicated in diverse biological and pathological processes. Importantly, a proposed common function is the internalization of collagen for intracellular degradation occurring during bone development, cancer invasion, and fibrosis protection. This functional relationship is suggested by a common endocytic capability and a candidate collagen-binding domain. Here we conducted a comparative investigation of each member's ability to facilitate intracellular collagen degradation. As expected, the family members uPARAP/Endo180 and MR bound collagens in a purified system and internalized collagens for degradation in cellular settings. In contrast, the remaining family members, PLA2R and DEC-205, showed no collagen binding activity and were unable to mediate collagen internalization. To pinpoint the structural elements discriminating collagen from non-collagen receptors, we constructed a series of receptor chimeras and loss- and gain-of-function mutants. Using this approach we identified a critical collagen binding loop in the suggested collagen binding region (an FN-II domain) in uPARAP/Endo180 and MR, which was different in PLA2R or DEC-205. However, we also found that an active FN-II domain was not a sufficient determinant to allow collagen internalization through these receptors. Nevertheless, this ability could be acquired by the transfer of a larger segment of uPARAP/Endo180 (the Cys-rich domain, the FN-II domain and two CTLDs) to DEC-205. These data underscore the importance of the FN-II domain in uPARAP/Endo180 and MR-mediated collagen internalization but at the same time uncover a critical interplay with flanking domains. PMID:24500714

  5. Complex determinants in specific members of the mannose receptor family govern collagen endocytosis.

    PubMed

    Jürgensen, Henrik J; Johansson, Kristina; Madsen, Daniel H; Porse, Astrid; Melander, Maria C; Sørensen, Kristine R; Nielsen, Christoffer; Bugge, Thomas H; Behrendt, Niels; Engelholm, Lars H

    2014-03-14

    Members of the well-conserved mannose receptor (MR) protein family have been functionally implicated in diverse biological and pathological processes. Importantly, a proposed common function is the internalization of collagen for intracellular degradation occurring during bone development, cancer invasion, and fibrosis protection. This functional relationship is suggested by a common endocytic capability and a candidate collagen-binding domain. Here we conducted a comparative investigation of each member's ability to facilitate intracellular collagen degradation. As expected, the family members uPARAP/Endo180 and MR bound collagens in a purified system and internalized collagens for degradation in cellular settings. In contrast, the remaining family members, PLA2R and DEC-205, showed no collagen binding activity and were unable to mediate collagen internalization. To pinpoint the structural elements discriminating collagen from non-collagen receptors, we constructed a series of receptor chimeras and loss- and gain-of-function mutants. Using this approach we identified a critical collagen binding loop in the suggested collagen binding region (an FN-II domain) in uPARAP/Endo180 and MR, which was different in PLA2R or DEC-205. However, we also found that an active FN-II domain was not a sufficient determinant to allow collagen internalization through these receptors. Nevertheless, this ability could be acquired by the transfer of a larger segment of uPARAP/Endo180 (the Cys-rich domain, the FN-II domain and two CTLDs) to DEC-205. These data underscore the importance of the FN-II domain in uPARAP/Endo180 and MR-mediated collagen internalization but at the same time uncover a critical interplay with flanking domains.

  6. 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

  7. 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…

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

    PubMed

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

    2016-10-13

    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.

  9. 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

  10. An ABA-regulated and Golgi-localized protein phosphatase controls water loss during leaf senescence in Arabidopsis.

    PubMed

    Zhang, Kewei; Xia, Xiuying; Zhang, Yanyan; Gan, Su-Sheng

    2012-02-01

    It is known that a senescing leaf loses water faster than a non-senescing leaf and that ABA has an important role in promoting leaf senescence. However, questions such as why water loss is faster, how water loss is regulated, and how ABA functions in leaf senescence are not well understood. Here we report on the identification and functional analysis of a leaf senescence associated gene called SAG113. The RNA blot and GUS reporter analyses all show that SAG113 is expressed in senescing leaves and is induced by ABA in Arabidopsis. The SAG113 expression levels are significantly reduced in aba2 and abi4 mutants. A GFP fusion protein analysis revealed that SAG113 protein is localized in the Golgi apparatus. SAG113 encodes a protein phosphatase that belongs to the PP2C family and is able to functionally complement a yeast PP2C-deficient mutant TM126 (ptc1Δ). Leaf senescence is delayed in the SAG113 knockout mutant compared with that in the wild type, stomatal movement in the senescing leaves of SAG113 knockouts is more sensitive to ABA than that of the wild type, and the rate of water loss in senescing leaves of SAG113 knockouts is significantly reduced. In contrast, inducible over-expression of SAG113 results in a lower sensitivity of stomatal movement to ABA treatment, more rapid water loss, and precocious leaf senescence. No other aspects of growth and development, including seed germination, were observed. These findings suggest that SAG113, a negative regulator of ABA signal transduction, is specifically involved in the control of water loss during leaf senescence.

  11. The barley HvNAC6 transcription factor affects ABA accumulation and promotes basal resistance against powdery mildew.

    PubMed

    Chen, Yan-Jun; Perera, Venura; Christiansen, Michael W; Holme, Inger B; Gregersen, Per L; Grant, Murray R; Collinge, David B; Lyngkjær, Michael F

    2013-12-01

    Barley HvNAC6 is a member of the plant-specific NAC (NAM, ATAF1,2, CUC2) transcription factor family and we have shown previously that it acts as a positive regulator of basal resistance in barley against the biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we use a transgenic approach to constitutively silence HvNAC6 expression, using RNA interference (RNAi), to investigate the in vivo functions of HvNAC6 in basal resistance responses in barley in relation to the phytohormone ABA. The HvNAC6 RNAi plants displayed reduced HvNAC6 transcript levels and were more susceptible to Bgh than wild-type plants. Application of exogenous ABA increased basal resistance against Bgh in wild-type plants, but not in HvNAC6 RNAi plants, suggesting that ABA is a positive regulator of basal resistance which depends on HvNAC6. Silencing of HvNAC6 expression altered the light/dark rhythm of ABA levels which were, however, not influenced by Bgh inoculation. The expression of the two ABA biosynthetic genes HvNCED1 and HvNCED2 was compromised, and transcript levels of the ABA conjugating HvBG7 enzyme were elevated in the HvNAC6 RNAi lines, but this effect was not clearly associated with transgene-mediated resistance. Together, these data support a function of HvNAC6 as a regulator of ABA-mediated defence responses for maintenance of effective basal resistance against Bgh.

  12. 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

  13. Positive and negative regulation of antigen receptor signaling by the Shc family of protein adapters.

    PubMed

    Finetti, Francesca; Savino, Maria Teresa; Baldari, Cosima T

    2009-11-01

    The Shc adapter family includes four members that are expressed as multiple isoforms and participate in signaling by a variety of cell-surface receptors. The biological relevance of Shc proteins as well as their variegated function, which relies on their highly conserved modular structure, is underscored by the distinct and dramatic phenotypic alterations resulting from deletion of individual Shc isoforms both in the mouse and in two model organisms, Drosophila melanogaster and Caenorhabditis elegans. The p52 isoform of ShcA couples antigen and cytokine receptors to Ras activation in both lymphoid and myeloid cells. However, the recognition of the spectrum of activities of p52ShcA in the immune system has been steadily expanding in recent years to other fundamental processes both at the cell and organism levels. Two other Shc family members, p66ShcA and p52ShcC/Rai, have been identified recently in T and B lymphocytes, where they antagonize survival and attenuate antigen receptor signaling. These developments reveal an unexpected and complex interplay of multiple Shc proteins in lymphocytes.

  14. Physiological functions of TNF family receptor/ligand interactions in hematopoiesis and transplantation.

    PubMed

    Mizrahi, Keren; Askenasy, Nadir

    2014-07-10

    Secretion of ligands of the tumor necrosis factor (TNF) superfamily is a conserved response of parenchymal tissues to injury and inflammation that commonly perpetuates elimination of dysfunctional cellular components by apoptosis. The same signals of tissue injury that induce apoptosis in somatic cells activate stem cells and initiate the process of tissue regeneration as a coupling mechanism of injury and recovery. Hematopoietic stem and progenitor cells upregulate the TNF family receptors under stress conditions and are transduced with trophic signals. The progeny gradually acquires sensitivity to receptor-mediated apoptosis along the differentiation process, which becomes the major mechanism of negative regulation of mature proliferating hematopoietic lineages and immune homeostasis. Receptor/ligand interactions of the TNF family are physiological mechanisms transducing the need for repair, which may be harnessed in pathological conditions and transplantation. Because these interactions are physiological mechanisms of injury, neutralization of these pathways has to be carefully considered in disorders that do not involve intrinsic aberrations of excessive susceptibility to apoptosis.

  15. Regulation of floral patterning and organ identity by Arabidopsis ERECTA-family receptor kinase genes.

    PubMed

    Bemis, Shannon M; Lee, Jin Suk; Shpak, Elena D; Torii, Keiko U

    2013-12-01

    Due to the lack of cell migration, plant organogenesis relies on coordinated cell proliferation, cell growth, and differentiation. A flower possesses a complex structure, with sepals and petals constituting the perianth, and stamens and pistils where male and female gametophytes differentiate. While advances have been made in our understanding of gene regulatory networks controlling flower development, relatively little is known of how cell-cell coordination influences floral organ specification. The Arabidopsis ERECTA (ER)-family receptor kinases, ER, ER-LIKE1 (ERL1), and ERL2, regulate inflorescence architecture, organ shape, and epidermal stomatal patterning. Here it is reported that ER-family genes together regulate floral meristem organization and floral organ identity. The stem cell marker CLAVATA3 exhibits misplaced expression in the floral meristems of the er erl1 erl2 mutant. Strikingly, homeotic conversion of sepals to carpels was observed in er erl1 erl2 flowers. Consistently, ectopic expression of AGAMOUS, which determines carpel identity, was detected in er erl1 erl2 flower primordia. Among the known downstream components of ER-family receptor kinases in stomatal patterning, YODA (YDA) is also required for proper floral patterning. YDA and the ER-family show complex, synergistic genetic interactions: er erl1 erl2 yda quadruple mutant plants become extremely small, callus-like masses. While a constitutively active YDA fully rescues stomatal clustering in er erl1 erl2, it only partially rescues er erl1 erl2 flower defects. The study suggests that ER-family signalling is crucial for ensuring proper expression domains of floral meristem and floral organ identity determinants, and further implies the existence of a non-canonical downstream pathway.

  16. Response to IL-1-receptor antagonist in a child with familial cold autoinflammatory syndrome.

    PubMed

    O'Connell, Susan M; O'Regan, Grainne M; Bolger, Turlough; Hoffman, Hal M; Cant, Andrew; Irvine, Alan D; Watson, Rosemarie M

    2007-01-01

    Familial cold auto-inflammatory syndrome, Muckle-Wells syndrome and chronic infantile neurologic, cutaneous, articular syndrome are related disorders associated with mutations in the CIAS1 gene. They appear to represent a continuum of one disease characterized by IL-1-mediated inflammation. Until recently, these conditions have been difficult to treat; however, with the advent of IL-1-receptor antagonist therapy, many reports of successful treatment of patients with these autoinflammatory diseases have emerged in the past 2 years. We describe an 8-year-old girl, diagnosed with Familial cold auto-inflammatory syndrome, confirmed by presence of a novel CIAS1 mutation, who was refractory to symptomatic treatment. As frequent attacks of urticaria and associated arthralgia had a debilitating effect on the child's lifestyle, a trial of IL-1-receptor antagonist (anakinra) was instituted. Dramatic sustained clinical improvement was evident within days and serum amyloid and C-reactive protein levels normalized within a month. Although several authors have reported successful use of this agent in children with chronic infantile neurologic, cutaneous, articular syndrome, we believe ours is the first report of successful treatment with anakinra in a young child with familial cold auto-inflammatory syndrome.

  17. The EGF receptor family--multiple roles in proliferation, differentiation, and neoplasia with an emphasis on HER4.

    PubMed Central

    Earp, H. Shelton; Calvo, Benjamin F.; Sartor, Carolyn I.

    2003-01-01

    The EGF Receptor (EGFR), the first transmembrane receptor tyrosine kinase cloned and sequenced, and its closely related family members HER2, HER3, and HER4, play myriad roles in mammalian growth and development. Receptor activation involves ligand binding to separate receptors followed by formation of active dimers. These receptors can signal as homodimers or they can subtly alter signaling output by heterodimerizing with other family members. Adding complexity, these receptors with varying specificity bind at least 10 ligands from two ligand families, the EGF and neuregulin/heregulin families. This signaling system's impact on human neoplasia is underscored by the following: i.) EGFR is overexpressed or activated by autocrine or paracrine growth factor loops in at least 50% of epithelial malignancies; ii.) HER2 is amplified and dramatically overexpressed in approximately 20%-25% or breast cancers; iii) HER3 and HER4 are variably expressed in breast and other cancers. Overexpression and/or activation of EGFR, HER2 and HER3 has been correlated with poor tumor prognosis; antibody and small molecule inhibitors of their activity are being tested as therapy in cancer patients. However, the signaling complexity engendered by four interacting receptors and ten ligands makes it difficult to definitively measure receptor signaling output in human tumors and even makes mechanistic studies of the family's role in normal physiology and neoplastic transformation a challenge. In spite of the literature's emphasis on growth control, activation by some EGF receptor family member ligands can produce tumor cell differentiation, characterized by growth cessation and differentiation gene product synthesis. The present work delineates a role for HER4 in breast cancer cell differentiation and demonstrates that HER4 is both necessary and sufficient to produce an anti-proliferative signal. These Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:12813928

  18. Wheat ABA-insensitive mutants result in reduced grain dormancy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes the isolation of wheat mutants in the hard red spring Scarlet resulting in reduced sensitivity to the plant hormone abscisic acid (ABA) during seed germination. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature seeds. Wheat sensitivity t...

  19. Investigation of Interactions at the Extracellular Loops of the Relaxin Family Peptide Receptor 1 (RXFP1)*

    PubMed Central

    Diepenhorst, Natalie A.; Petrie, Emma J.; Chen, Catherine Z.; Wang, Amy; Hossain, Mohammed Akhter; Bathgate, Ross A. D.; Gooley, Paul R.

    2014-01-01

    Relaxin, an emerging pharmaceutical treatment for acute heart failure, activates the relaxin family peptide receptor (RXFP1), which is a class A G-protein-coupled receptor. In addition to the classic transmembrane (TM) domain, RXFP1 possesses a large extracellular domain consisting of 10 leucine-rich repeats and an N-terminal low density lipoprotein class A (LDLa) module. Relaxin-mediated activation of RXFP1 requires multiple coordinated interactions between the ligand and various receptor domains including a high affinity interaction involving the leucine-rich repeats and a predicted lower affinity interaction involving the extracellular loops (ELs). The LDLa is essential for signal activation; therefore the ELs/TM may additionally present an interaction site to facilitate this LDLa-mediated signaling. To overcome the many challenges of investigating relaxin and the LDLa module interactions with the ELs, we engineered the EL1 and EL2 loops onto a soluble protein scaffold, mapping specific ligand and loop interactions using nuclear magnetic resonance spectroscopy. Key EL residues were subsequently mutated in RXFP1, and changes in function and relaxin binding were assessed alongside the RXFP1 agonist ML290 to monitor the functional integrity of the TM domain of these mutant receptors. The outcomes of this work make an important contribution to understanding the mechanism of RXFP1 activation and will aid future development of small molecule RXFP1 agonists/antagonists. PMID:25352603

  20. 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

  1. Differential expression of CD150 (SLAM) family receptors by human hematopoietic stem and progenitor cells

    PubMed Central

    Sintes, Jordi; Romero, Xavier; Marin, Pedro; Terhorst, Cox; Engel, Pablo

    2015-01-01

    Objectives Human hematopoietic stem cell (HSC)–containing grafts are most commonly used to treat various blood diseases, including leukemias and autoimmune disorders. CD150 (SLAM) family receptors have recently been shown to be differentially expressed by mouse HSC and progenitor cells. Members of the CD150 family are key regulators of leukocyte activation and differentiation. The goal of the present study is to analyze the expression patterns of the CD150 receptors CD48, CD84, CD150 (SLAM), CD229 (Ly9), and CD244 (2B4) on the different sources of human hematopoietic stem and progenitor cells. Materials and Methods Expression of CD150 receptors was analyzed on human mobilized peripheral blood CD133+-isolated cells and CD34+ bone marrow (BM) and umbilical cord blood (CB) cells using multicolor flow cytometry. Results CD244 was present on most CD133+Lin−-mobilized cells and CD34+Lin− BM and CB cells, including virtually all CD38−Lin− primitive progenitor cells. CD48 had a restricted expression pattern on CD133+Lin−CD38− cells, while its levels were significantly higher in CD34+Lin− BM and CB cells. In addition, CD84 was present on a significant number of CD133+Lin− cells, but only on a small fraction of CD133+Lin−CD38− peripheral blood mobilized cells. In contrast, CD84 was expressed on practically all CD34+Lin− BM cells. No CD150 expression was observed in mobilized peripheral blood CD133+Lin− or CD34+Lin− BM and CB cells. Furthermore, only a small fraction of CD34+Lin− BM and CB cells expressed CD229. Conclusions Our results show that CD150 family molecules are present on human hematopoietic stem and progenitor cells and that their expression patterns differ between humans and mice. PMID:18495325

  2. 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

  3. Association of Killer Cell Immunoglobulin-Like Receptor Genes with Hodgkin's Lymphoma in a Familial Study

    PubMed Central

    Williams, Fionnuala; Orsi, Laurent; Amiel, Corinne; Lependeven, Catherine; Antoni, Guillemette; Hermine, Olivier; Brice, Pauline; Ferme, Christophe; Carde, Patrice; Canioni, Danielle; Brière, Josette; Raphael, Martine; Nicolas, Jean-Claude; Clavel, Jacqueline; Middleton, Derek; Vivier, Eric; Abel, Laurent

    2007-01-01

    Background Epstein-Barr virus (EBV) is the major environmental factor associated with Hodgkin's lymphoma (HL), a common lymphoma in young adults. Natural killer (NK) cells are key actors of the innate immune response against viruses. The regulation of NK cell function involves activating and inhibitory Killer cell Immunoglobulin-like receptors (KIRs), which are expressed in variable numbers on NK cells. Various viral and virus-related malignant disorders have been associated with the presence/absence of certain KIR genes in case/control studies. We investigated the role of the KIR cluster in HL in a family-based association study. Methodology We included 90 families with 90 HL index cases (age 16–35 years) and 255 first-degree relatives (parents and siblings). We developed a procedure for reconstructing full genotypic information (number of gene copies) at each KIR locus from the standard KIR gene content. Out of the 90 collected families, 84 were informative and suitable for further analysis. An association study was then carried out with specific family-based analysis methods on these 84 families. Principal Findings Five KIR genes in strong linkage disequilibrium were found significantly associated with HL. Refined haplotype analysis showed that the association was supported by a dominant protective effect of KIR3DS1 and/or KIR2DS1, both of which are activating receptors. The odds ratios for developing HL in subjects with at least one copy of KIR3DS1 or KIR2DS1 with respect to subjects with neither of these genes were 0.44[95% confidence interval 0.23–0.85] and 0.42[0.21–0.85], respectively. No significant association was found in a tentative replication case/control study of 68 HL cases (age 18–71 years). In the familial study, the protective effect of KIR3DS1/KIR2DS1 tended to be stronger in HL patients with detectable EBV in blood or tumour cells. Conclusions This work defines a template for family-based association studies based on full genotypic

  4. Normal and Cancer-Related Functions of the p160 Steroid Receptor Coactivator (SRC) Family

    PubMed Central

    Xu, Jianming; Wu, Ray-Chang; O’Malley, Bert W.

    2010-01-01

    The three homologous members of the p160 SRC family (SRC-1, SRC-2 and SRC-3) mediate the transcriptional functions of nuclear receptors and other transcription factors, and are the most studied of all transcriptional coactivators. Recent work has indicated that the SRC genes are subject to amplification and overexpression in various human cancers. Some of the molecular mechanisms responsible for SRC overexpression along with the mechanisms by which SRCs promote breast and prostate cancer cell proliferation and survival have been identified, as have the specific contributions of individual SRC family members in spontaneous breast and prostate carcinogenesis in genetically manipulated mouse models. These studies have identified new challenges for cancer research and therapy. PMID:19701241

  5. 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.

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

    PubMed

    Wang, Song; Xu, Haikun; An, Wei; Zhu, Dechun; Li, Dejun

    2016-06-01

    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.

  7. 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

  8. 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

  9. 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

  10. Three austin family compounds from Penicillium brasilianum exhibit selective blocking action on cockroach nicotinic acetylcholine receptors.

    PubMed

    Kataoka, Saori; Furutani, Shogo; Hirata, Koichi; Hayashi, Hideo; Matsuda, Kazuhiko

    2011-01-01

    Austin (AT) and its derivatives (dehydroaustin (DAT) and acetoxydehydroaustin (ADAT)) produced by Penicillium brasilianum MG-11 exhibit toxicity to insects, yet their targets are unknown. Here, we used whole-cell patch-clamp electrophysiology to investigate the action of AT family compounds on cockroach acetylcholine (ACh), γ-aminobutyric acid (GABA) and l-glutamate receptors expressed in the American cockroach (Periplaneta americana) neuron. U-tube application of AT or its derivatives did not induce any current amplitudes, suggesting that they did not act as agonist of these three receptors. In the second step of experiments, they were bath-applied for 1min before co-application with the corresponding ligand. We found that AT and its derivatives had no effect on GABA and l-glutamate-induced currents, whereas they significantly reduced ACh- and epibatidine-induced currents, showing that these compounds acted as selective antagonists of nicotinic acetylcholine receptors (nAChRs) expressed in the cockroach neuron. Of the compounds, DAT showed the highest blocking potency for nAChRs, differentially attenuating the peak and slowly desensitizing current amplitude of ACh-induced responses with pIC(50) (=-logIC(50) (M)) values of 6.11 and 5.91, respectively. DAT reduced the maximum normalized response to ACh without a significant shift in EC(50), suggesting that the blocking action is not competitive with ACh.

  11. Nitric oxide and ABA in the control of plant function.

    PubMed

    Hancock, J T; Neill, S J; Wilson, I D

    2011-11-01

    Abscisic acid (ABA) and nitric oxide (NO) are both extremely important signalling molecules employed by plants to control many aspects of physiology. ABA has been extensively studied in the mechanisms which control stomatal movement as well as in seed dormancy and germination and plant development. The addition of either ABA or NO to plant cells is known to instigate the actions of many signal transduction components. Both may have an influence on the phosphorylation of proteins in cells mediated by effects on protein kinases and phosphatases, as well as recruiting a wide range of other signal transduction molecules to mediate the final effects. Both ABA and NO may also lead to the regulation of gene expression. However, it is becoming more apparent that NO may be acting downstream of ABA, with such action being mediated by reactive oxygen species such as hydrogen peroxide in some cases. However not all ABA responses require the action of NO. Here, examples of where ABA and NO have been put together into the same signal transduction pathways are discussed.

  12. 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.

  13. 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.

  14. Molecular characterisation of the STRUBBELIG-RECEPTOR FAMILY of genes encoding putative leucine-rich repeat receptor-like kinases in Arabidopsis thaliana

    PubMed Central

    Eyüboglu, Banu; Pfister, Karen; Haberer, Georg; Chevalier, David; Fuchs, Angelika; Mayer, Klaus FX; Schneitz, Kay

    2007-01-01

    Background Receptor-like kinases are a prominent class of surface receptors that regulate many aspects of the plant life cycle. Despite recent advances the function of most receptor-like kinases remains elusive. Therefore, it is paramount to investigate these receptors. The task is complicated by the fact that receptor-like kinases belong to a large monophyletic family with many sub-clades. In general, functional analysis of gene family members by reverse genetics is often obscured by several issues, such as redundancy, subtle or difficult to detect phenotypes in mutants, or by decision problems regarding suitable biological and biochemical assays. Therefore, in many cases additional strategies have to be employed to allow inference of hypotheses regarding gene function. Results We approached the function of genes encoding the nine-member STRUBBELIG-RECEPTOR FAMILY (SRF) class of putative leucine-rich repeat receptor-like kinases. Sequence comparisons show overall conservation but also divergence in predicted functional domains among SRF proteins. Interestingly, SRF1 undergoes differential splicing. As a result, SRF1 is predicted to exist in a standard receptor configuration and in a membrane-anchored receptor-like version that lacks most of the intracellular domain. Furthermore, SRF1 is characterised by a high degree of polymorphism between the Ler and Col accessions. Two independent T-DNA-based srf4 mutants showed smaller leaves while 35S::SRF4 plants displayed enlarged leaves. This is in addition to the strubbelig phenotype which has been described before. Additional single and several key double mutant combinations did not reveal obvious mutant phenotypes. Ectopic expression of several SRF genes, using the 35S promoter, resulted in male sterility. To gain possible insights into SRF gene function we employed a computational analysis of publicly available microarray data. We performed global expression profiling, coexpression analysis, and an analysis of the

  15. 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

  16. 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.

  17. Unnatural agrochemical ligands for engineered abscisic acid receptors.

    PubMed

    Rodriguez, Pedro L; Lozano-Juste, Jorge

    2015-06-01

    Existing agrochemicals can be endowed with new applications through protein engineering of plant receptors. A recent study shows an engineered PYR1 ABA receptor can be activated by mandipropamid. Plants engineered with such PYR1 variant are responsive to this agrochemical, which confers protection against drought through activation of ABA signaling.

  18. Electrophysiological properties of AMPA receptors are differentially modulated depending on the associated member of the TARP family.

    PubMed

    Kott, Sabine; Werner, Markus; Körber, Christoph; Hollmann, Michael

    2007-04-04

    The family of AMPA receptors is encoded by four genes that are differentially spliced to result in the flip or flop versions of the four subunits GluR1 to GluR4. GluR2 is further modified at the so-called Q/R site by posttranscriptional RNA editing. Delivery of AMPA receptors to the plasma membrane and synaptic trafficking are controlled by transmembrane AMPA receptor regulatory proteins (TARPs). Additionally, TARPs influence essential electrophysiological properties of AMPA receptor channels such as desensitization and agonist efficacies. Here, we compare the influence of all known TARPs (gamma2, gamma3, gamma4, and gamma8) on agonist-induced currents of the four AMPA receptor subunits, including flip and flop splice variants and editing variants. We show that, although agonist-induced currents of all homomeric AMPA receptor subunits as well as all heteromeric combinations tested are significantly potentiated when coexpressed with members of the TARP family in Xenopus laevis oocytes, the extent of TARP-mediated increase in agonist-induced responses is highly dependent on both the AMPA receptor subunit and the coexpressed TARP. Moreover, we demonstrate that the splice variant of the AMPA receptor plays a key role in determining the modulation of electrophysiological properties by associated TARPs. We furthermore present evidence that individual TARP-AMPA receptor interactions control the degree of desensitization of AMPA receptors. Consequently, because of their subunit-specific impact on the electrophysiological properties, TARPs play a major role as modulatory subunits of AMPA receptors and thus contribute to the functional diversity of AMPA receptors encountered in the CNS.

  19. 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.

  20. Familial hypercholesterolemia in a rhesus monkey pedigree: molecular basis of low density lipoprotein receptor deficiency.

    PubMed Central

    Hummel, M; Li, Z G; Pfaffinger, D; Neven, L; Scanu, A M

    1990-01-01

    We have recently identified a family of rhesus monkeys with members exhibiting a spontaneous hypercholesterolemia associated with a low density lipoprotein receptor (LDLR) deficiency. By using the polymerase chain reaction, we now show that the affected monkeys are heterozygous for a nonsense mutation in exon 6 of the LDLR gene. This mutation changes the sequence of the codon for amino acid 284 (tryptophan) from TGG to TAG, thereby generating a nonsense codon potentially resulting in a truncated 283-amino acid protein, which needs documentation, however. This G----A mutation also creates a site for the restriction endonuclease Spe I. Using this site as a marker for this nonsense mutation, we have shown that the mutation is present in all of the affected members of the pedigree and absent in unaffected members and that the mutation segregates with the phenotype of spontaneous hypercholesterolemia through three generations. Quantitative analyses of RNA obtained from liver biopsies show that the abundance of the LDLR RNA is also reduced by about 50%. Thus, we have identified a primate model for human familial hypercholesterolemia which will be useful for studying the relationship between the LDLR and lipoprotein metabolism and for assessing the efficacy of diets and drugs in the treatment of human familial hypercholesterolemia. Images PMID:2326270

  1. Cloning of two members of the calcitonin-family receptors from stingray, Dasyatis akajei: possible physiological roles of the calcitonin family in osmoregulation.

    PubMed

    Suzuki, Nobuo; Sekiguchi, Toshio; Satake, Honoo; Kato, Kanoko; Nishiyama, Yudai; Takahashi, Hideya; Danks, Janine A; Martin, T John; Hattori, Atsuhiko; Nakano, Masaki; Kakikawa, Makiko; Yamada, Sotoshi; Ogoshi, Maho; Hyodo, Susumu; Yamaguchi, Yoko; Chowdhury, Vishwajit S; Hayakawa, Kazuichi; Funahashi, Hisayuki; Sakamoto, Tatsuya; Sasayama, Yuichi

    2012-05-15

    In cartilaginous fish, two cDNAs encoding calcitonin-family receptors were isolated for the first time from the stingray brain. The open reading frame of one receptor cDNA coded a 525-amino acid protein. The amino acid identity of this receptor to human calcitonin-receptor-like receptor (CRLR) is 64.5%, frog CRLR is 64.7%, and flounder CRLR is 61.2% and this was higher than to human calcitonin receptor (CTR) (46.1%), frog CTR (54.7%), and flounder CTR (48.9%). We strongly suggested that this receptor is a ray CRLR based on phylogenetic analysis. In case of the second receptor, amino acid identity among CRLRs (human 50.5%, frog 50.7%, flounder 48.0%) and CTRs (human 43.2%, frog 49.1%, flounder 41.8%) was similar. From phylogenetic analysis of both CRLRs and CTRs, we believe that this receptor is ray CTR. The expression of ray CRLR mRNA was predominantly detected in the nervous system (brain) and vascular system (atrium, ventricle, and gill), which reflects the similar localization of CGRP in the nervous and vascular systems as mammals. It was observed that the second receptor was expressed in several tissues, namely cartilage, brain, pituitary gland, gill, atrium, ventricle, pancreas, spleen, liver, gall bladder, intestine, rectal gland, kidney, testis and ovary. This localization pattern was very similar to flounder CTR. Both receptor mRNAs were strongly expressed in the gill. This suggests that the calcitonin-family members are involved in the osmoregulation of stingray as this fish is known to be euryhaline. When a stingray was transferred to diluted seawater (20% seawater), the expression of both receptors significantly decreased in the gill. Similar results were obtained in the kidney of the stingray. Thus, our cloning and isolation of both receptors in the stingray will be helpful for elucidation of their physiological role(s) such as osmoregulation including calcium metabolism of cartilaginous fish.

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

    PubMed

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

    2010-03-01

    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 FcRgamma subunit. Our findings suggest that if KRIRs of various vertebrates have any common function at all, such a function is activating rather than inhibitory.

  3. Insights into the structural basis of endogenous agonist activation of family B G protein-coupled receptors.

    PubMed

    Dong, Maoqing; Gao, Fan; Pinon, Delia I; Miller, Laurence J

    2008-06-01

    Agonist drugs targeting the glucagon-like peptide-1 (GLP1) receptor represent important additions to the clinical management of patients with diabetes mellitus. In the current report, we have explored whether the recently described concept of a receptor-active endogenous agonist sequence within the amino terminus of the secretin receptor may also be applicable to the GLP1 receptor. If so, this could provide a lead for the development of additional small molecule agonists targeting this and other important family members. Indeed, the region of the GLP1 receptor analogous to that containing the active WDN within the secretin receptor was found to possess full agonist activity at the GLP1 receptor. The minimal fragment within this region that had full agonist activity was NRTFD. Despite having no primary sequence identity with the WDN, it was also active at the secretin receptor, where it had similar potency and efficacy to WDN, suggesting common structural features. Molecular modeling demonstrated that an intradomain salt bridge between the side chains of arginine and aspartate could yield similarities in structure with cyclic WDN. This directly supports the relevance of the endogenous agonist concept to the GLP1 receptor and provides new insights into the rational development and refinement of new types of drugs activating this important receptor.

  4. 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

  5. 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

  6. The L-, N-, and T-type triple calcium channel blocker benidipine acts as an antagonist of mineralocorticoid receptor, a member of nuclear receptor family.

    PubMed

    Kosaka, Hiromichi; Hirayama, Kazunori; Yoda, Nobuyuki; Sasaki, Katsutoshi; Kitayama, Tetsuya; Kusaka, Hideaki; Matsubara, Masahiro

    2010-06-10

    Aldosterone-induced activation of mineralocorticoid receptor, a member of the nuclear receptor family, results in increased tissue damage such as vascular inflammation and cardiac and perivascular fibrosis. Benidipine, a long-lasting dihydropyridine calcium channel blocker, is used for hypertension and angina. Benidipine exhibits pleiotropic pharmacological features such as renoprotective and cardioprotective effects through triple blockade of L-, N-, and T-type calcium channels. However, the mechanism of additional beneficial effects on end-organ damage is poorly understood. Here, we examined the effects of benidipine and other calcium channel blockers on aldosterone-induced mineralocorticoid receptor activation using luciferase reporter assay system. Benidipine showed more potent activity than efonidipine, amlodipine, or azelnidipine. Benidipine depressed the response to higher concentrations of aldosterone, whereas pretreatment of eplerenone, a steroidal mineralocorticoid receptor antagonist, did not. Binding studies using [(3)H] aldosterone indicated that benidipine and other calcium channel blockers competed for binding to mineralocorticoid receptor. Benidipine and other calcium channel blockers showed antagonistic activity on Ser810 to Leu mutant mineralocorticoid receptor, which is identified in patients with early-onset hypertension. On the other hand, eplerenone partially activated the mutant. Results of analysis using optical isomers of benidipine indicated that inhibitory effect of aldosterone-induced mineralocorticoid receptor activation was independent of its primary blockade of calcium channels. These results suggested that benidipine directly inhibits aldosterone-induced mineralocorticoid receptor activation, and the antagonistic activity might contribute to the drug's pleiotropic pharmacological features.

  7. Genetically determined hypercholesterolemia in a rhesus monkey family due to a deficiency of the LDL receptor.

    PubMed

    Scanu, A M; Khalil, A; Neven, L; Tidore, M; Dawson, G; Pfaffinger, D; Jackson, E; Carey, K D; McGill, H C; Fless, G M

    1988-12-01

    A family of rhesus monkeys comprising a sire, a dam, and four male offspring were fed a cholesterol-free Purina Chow diet for several months. The sire, 431-J, and two of the offspring, B-8204 and B-8806, had persistent plasma cholesterol levels in the range of 100-130 mg/dl, whereas the dam, 766-I, and the two other offspring, B-1000 and B-7643, exhibited a marked hypercholesterolemia in the 250-300 mg/dl range associated with an elevation of plasma LDL and apoB. When fed for 12 weeks a diet containing 12.5% lard and 0.25% cholesterol, sire, dam, B-1000 and B-7643 exhibited a marked hypercholesterolemia (500-800 mg/dl range), whereas B-8204 and B-8806 developed only a modest hypercholesterolemia (200-250 mg/dl). All animals were Lp[a]+. Skin fibroblasts from each animal and from control cells were grown in 10% fetal calf serum, transferred to 10% lipoprotein-deficient serum for 48 hr, and then incubated at 4 degrees C or 37 degrees C with 125I-labeled Lp[a]-free LDL. The fibroblasts from dam and offspring B-1000 and B-7643 bound and internalized 125I-labeled LDL less efficiently than control cells. Mathematical analyses of the 4 degrees C binding data indicated that there were no significant differences in LDL binding affinity between test and control cells suggesting that cells from the animals with a spontaneous hypercholesterolemia had a decreased number of LDL receptors. This conclusion was supported by the results of ligand and immunoblot analyses carried out on cell lysates separated by gradient gel electrophoresis. We conclude that a genetically determined LDL receptor deficiency was responsible, in part, for the spontaneous hypercholesterolemia observed in three out of the six family members and that this deficiency accounted for the hyperresponsiveness to a dietary fat and cholesterol challenge by the dam and the two offspring, B-1000 and B-7643. The hyperresponsiveness noted in the sire that had no evidence for LDL-receptor deficiency illustrates that

  8. 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

  9. 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

  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. Characterization of the ABA signal transduction pathway in Vitis vinifera.

    PubMed

    Boneh, Uri; Biton, Iris; Schwartz, Amnon; Ben-Ari, Giora

    2012-05-01

    The plant hormone abscisic acid (ABA) regulates many key processes in plants including the response to abiotic stress. ABA signal transduction consists of a double-negative regulatory mechanism, whereby ABA-bound PYR/RCARs inhibit PP2C activity, and PP2Cs inactivate SnRK2s. We studied and analyzed the various genes participating in the ABA signaling cascade of the grape (Vitis vinifera). The grape ABA signal transduction consists of at least six SnRK2s. Yeast two-hybrid system was used to test direct interactions between core components of grape ABA signal transduction. We found that a total of forty eight interactions can occur between the various components. Exogenous abscisic acid (ABA) and abiotic stresses such as drought, high salt concentration and cold, were applied to vines growing in a hydroponic system. These stresses regulated the expression of various grape SnRK2s as well as ABFs in leaves and roots. Based on the interactions between SnRK2s and its targets and the expression pattern, we suggest that VvSnRK2.1 and VvSnRK2.6, can be considered the major VvSnRK2 candidates involved in the stomata response to abiotic stress. Furthermore, we found that the expression pattern of the two grape ABF genes indicates organ specificity of these genes. The key role of ABA signaling in response to abiotic stresses makes the genes involve in this signaling potential candidates for manipulation in programs designed to improve fruit tree performance in extreme environments.

  12. abaA controls phialide differentiation in Aspergillus nidulans.

    PubMed Central

    Sewall, T C; Mims, C W; Timberlake, W E

    1990-01-01

    Aspergillus nidulans is an ascomycetous fungus that reproduces asexually by forming multicellular conidiophores and uninucleate spores called conidia. Loss of function mutations in the abacus A (abaA) regulatory locus result in formation of aberrant conidiophores that fail to produce conidia. Wild-type conidiophores form two tiers of sterigmata. The first tier, metulae, divide to produce the second tier, phialides. Phialides are sporogenous cells that produce conidia through a specialized apical budding process. We have examined conidiophore development in an abaA- strain at the ultrastructural level. The results showed that in the mutant metulae produce supernumerary tiers of cells with metula-like, rather than phialide-like, properties. Temperature shift experiments with an abaA14ts strain demonstrated that abaA+ function induced phialide formation by the aberrant abacus cells and was continuously required for maintenance of phialide function. In the absence of abaA+ activity, metulae simply proliferated and later developmental steps never occurred. We conclude that abaA+ directs the differentiation of phialides and is continuously required for maintenance of their function. PMID:2152124

  13. Are hormones from the neuropeptide Y family recognized by their receptors from the membrane-bound state?

    PubMed

    Bader, Reto; Zerbe, Oliver

    2005-09-01

    Hormones and many other neurotransmitters, growth factors, odorant molecules, and light all present stimuli for a class of membrane-anchored receptors called G protein-coupled receptors (GPCRs). The GPCRs are the largest family of cell-surface receptors involved in signal transduction. About 1% of all known genes of Drosophila and more than 5% of the genes of Caenorhabditis elegans encode GPCRs. In addition, more than 50% of current therapeutic agents on the market target these receptors. When the enormous biological and pharmaceutical importance of these receptors is considered, it is surprising how little is known about the mechanism with which these receptors recognize their natural ligands. In this review we present a structural approach, utilizing techniques of high-resolution NMR spectroscopy, to address the question of whether peptides from the neuropeptide Y family of neurohormones are recognized directly from solution or from the membrane-bound state. In our studies we discovered that the structures of the membrane-bound species are better correlated to the pharmacological properties of these peptides than the solution structures are. These findings are supported by the observation that many biophysical properties of these peptides seem to be optimized for membrane binding. We finally present a scenario of possible events during receptor recognition.

  14. 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.

  15. Conserved residues in the HAMP domain define a new family of proposed bipartite energy taxis receptors.

    PubMed

    Elliott, Kathryn T; Zhulin, Igor B; Stuckey, Jeanne A; DiRita, Victor J

    2009-01-01

    HAMP domains, found in many bacterial signal transduction proteins, generally transmit an intramolecular signal between an extracellular sensory domain and an intracellular signaling domain. Studies of HAMP domains in proteins where both the input and output signals occur intracellularly are limited to those of the Aer energy taxis receptor of Escherichia coli, which has both a HAMP domain and a sensory PAS domain. Campylobacter jejuni has an energy taxis system consisting of the domains of Aer divided between two proteins, CetA (HAMP domain containing) and CetB (PAS domain containing). In this study, we found that the CetA HAMP domain differs significantly from that of Aer in the predicted secondary structure. Using similarity searches, we identified 55 pairs of HAMP/PAS proteins encoded by adjacent genes in a diverse group of microorganisms. We propose that these HAMP/PAS pairs form a new family of bipartite energy taxis receptors. Within these proteins, we identified nine residues in the HAMP domain and proximal signaling domain that are highly conserved, at least three of which are required for CetA function. Additionally, we demonstrated that CetA contributes to the invasion of human epithelial cells by C. jejuni, while CetB does not. This finding supports the hypothesis that members of HAMP/PAS pairs possess the capacity to act independently of each other in cellular traits other than energy taxis.

  16. Neuroprotective Effects of a Structurally New Family of High Affinity Imidazoline I2 Receptor Ligands.

    PubMed

    Abás, Sònia; Erdozain, Amaia M; Keller, Benjamin; Rodríguez-Arévalo, Sergio; Callado, Luis F; García-Sevilla, Jesús A; Escolano, Carmen

    2017-01-04

    The imidazoline I2 receptors (I2-IRs) are widely distributed in the brain, and I2-IR ligands may have therapeutic potential as neuroprotective agents. Since structural data for I2-IR remains unknown, the discovery of selective I2-IR ligands devoid of α2-adrenoceptor (α2-AR) affinity is likely to provide valuable tools in defining the pharmacological characterization of these receptors. We report the pharmacological characterization of a new family of (2-imidazolin-4-yl)phosphonates. Radioligand binding studies showed that they displayed a higher affinity for I2-IRs than idazoxan, and high I2/α2 selectivity. In vivo studies in mice showed that acute treatments with 1b and 2c significantly increased p-FADD/FADD ratio (an index of cell survival) in the hippocampus when compared with vehicle-treated controls. Additionally, acute and repeated treatments with 2c, but not with 1b, markedly reduced hippocampal p35 cleavage into neurotoxic p25. The present results indicate a neuroprotective potential of (2-imidazolin-4-yl)phosphonates acting at I2-IRs.

  17. The molecular basis of ABA-independent inhibition of PP2Cs by a subclass of PYL proteins.

    PubMed

    Hao, Qi; Yin, Ping; Li, Wenqi; Wang, Li; Yan, Chuangye; Lin, Zhaohu; Wu, Jim Zhen; Wang, Jiawei; Yan, S Frank; Yan, Nieng

    2011-06-10

    PYR1/PYL/RCAR proteins (PYLs) are confirmed abscisic acid (ABA) receptors, which inhibit protein phosphatase 2C (PP2C) upon binding to ABA. Arabidopsis thaliana has 14 PYLs, yet their functional distinction remains unclear. Here, we report systematic biochemical characterization of PYLs. A subclass of PYLs, represented by PYL10, inhibited PP2C in the absence of any ligand. Crystal structures of PYL10, both in the free form and in the HAB1 (PP2C)-bound state, revealed the structural basis for its constitutive activity. Structural-guided biochemical analyses revealed that ABA-independent inhibition of PP2C requires the PYLs to exist in a monomeric state. In addition, the residues guarding the entrance to the ligand-binding pocket of these PYLs should be bulky and hydrophobic. Based on these principles, we were able to generate monomeric PYL2 variants that gained constitutive inhibitory effect on PP2Cs. These findings provide an important framework for understanding the complex regulation of ABA signaling by PYL proteins.

  18. LRAD3, a Novel LDL Receptor Family Member that Modulates Amyloid Precursor Protein Trafficking

    PubMed Central

    Ranganathan, Sripriya; Noyes, Nathaniel C.; Migliorini, Mary; Winkles, Jeffrey A.; Battey, Frances D.; Hyman, Bradley T.; Smith, Elizabeth; Yepes, Manuel; Mikhailenko, Irina; Strickland, Dudley K.

    2011-01-01

    We have identified a novel LDL receptor family member, termed LDL receptor class A domain containing 3 (LRAD3), which is expressed in neurons. The LRAD3 gene encodes an approximately 50 kDa type I transmembrane receptor with an ectodomain containing three LDLa repeats, a transmembrane domain and a cytoplasmic domain containing a conserved dileucine internalization motif and two polyproline motifs with potential to interact with WW domain containing proteins. Immunohistochemical analysis of mouse brain reveals LRAD3 expression in the cortex and hippocampus. In the mouse hippocampal derived cell line, HT22, LRAD3 partially co-localizes with amyloid precursor protein (APP), and interacts with APP as revealed by co-immunoprecipitation experiments. To identify the portion of APP that interacts with LRAD3, we employed solid phase binding assays which demonstrated that LRAD3 failed to bind to a soluble APP fragment (sAPPα) released following α-secretase cleavage. In contrast, C99, the β-secretase product that remains cell associated, co-precipitated with LRAD3, confirming that regions within this portion of APP are important for associating with LRAD3. The association of LRAD3 with APP increases the amyloidogenic pathway of APP processing, resulting in a decrease in sAPPα production and increased Aβ peptide production. Pulse-chase experiments confirm that LRAD3 expression significantly decreases the cellular half-live of mature APP. These results reveal that LRAD3 influences APP processing and raises the possibility that LRAD3 alters APP function in neurons including its downstream signaling. PMID:21795536

  19. 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

  20. Ror family receptor tyrosine kinases regulate the maintenance of neural progenitor cells in the developing neocortex.

    PubMed

    Endo, Mitsuharu; Doi, Ryosuke; Nishita, Michiru; Minami, Yasuhiro

    2012-04-15

    The Ror family receptor tyrosine kinases (RTKs), Ror1 and Ror2, have been shown to play crucial roles in developmental morphogenesis by acting as receptors or co-receptors to mediate Wnt5a-induced signaling. Although Ror1, Ror2 and Wnt5a are expressed in the developing brain, little is known about their roles in the neural development. Here we show that Ror1, Ror2 and their ligand Wnt5a are highly expressed in neocortical neural progenitor cells (NPCs). Small interfering RNA (siRNA)-mediated suppression of Ror1, Ror2 or Wnt5a in cultured NPCs isolated from embryonic neocortex results in the reduction of βIII-tubulin-positive neurons that are produced from NPCs possibly through the generation of T-box brain 2 (Tbr2)-positive intermediate progenitors. BrdU-labeling experiments further reveal that the proportion of proliferative and neurogenic NPCs, which are positive for neural progenitor cell marker (Pax6) but negative for glial cell marker (glial fibrillary acidic protein; GFAP), is reduced within a few days in culture following knockdown of these molecules, suggesting that Ror1, Ror2 and Wnt5a regulate neurogenesis through the maintenance of NPCs. Moreover, we show that Dishevelled 2 (Dvl2) is involved in Wnt5a-Ror1 and Wnt5a-Ror2 signaling in NPCs, and that suppressed expression of Dvl2 indeed reduces the proportion of proliferative and neurogenic NPCs. Interestingly, suppressed expression of either Ror1 or Ror2 in NPCs in the developing neocortex results in the precocious differentiation of NPCs into neurons, and their forced expression results in delayed differentiation. Collectively, these results indicate that Wnt5a-Ror1 and Wnt5a-Ror2 signaling pathways play roles in maintaining proliferative and neurogenic NPCs during neurogenesis of the developing neocortex.

  1. Expression, clinical significance, and receptor identification of the newest B7 family member HHLA2 protein

    PubMed Central

    Janakiram, Murali; Chinai, Jordan M; Fineberg, Susan; Fiser, Andras; Montagna, Cristina; Medaverepu, Ramadevi; Castano, Ekaterina; Jeon, Hyungjun; Ohaegbulam, Kim C; Zhao, Ruihua; Zhao, Aimin; Almo, Steven C.; Sparano, Joseph A; Zang, Xingxing

    2014-01-01

    Purpose HHLA2 (B7H7/B7-H5/B7y) is a newly identified B7 family member that regulates human T cell functions. However, its protein expression in human organs and significance in human diseases are unknown. The objective of this study was to analyze HHLA2 protein expression in normal human tissues and cancers, its prognostic significance, to explore mechanisms regulating HHLA2 expression, and to identify candidate HHLA2 receptors. Experimental Design An immunohistochemistry protocol and a flow cytometry assay with newly generated monoclonal antibodies were developed to examine HHLA2 protein. HHLA2 gene copy number variation was analyzed from cancer genomic data. The combination of bioinformatics analysis and immunological approaches was established to explore HHLA2 receptors. Results HHLA2 protein was detected in trophoblastic cells of the placenta and the epithelium of gut, kidney, gallbladder and breast, but not in most other organs. In contrast, HHLA2 protein was widely expressed in human cancers from the breast, lung, thyroid, melanoma, pancreas, ovary, liver, bladder, colon, prostate, kidney, and esophagus. In a cohort of 50 patients with stage I–III triple negative breast cancer, 56% of patients had aberrant expression of HHLA2 on their tumors, and high HHLA2 expression was significantly associated with regional lymph node metastasis and stage. The Cancer Genome Atlas revealed that HHLA2 copy number gains were present in 29% of basal breast cancers, providing a potential mechanism for increased HHLA2 protein expression in breast cancer. Finally, Transmembrane and Immunoglobulin Domain Containing 2 (TMIGD2) was identified as one of the receptors for HHLA2. Conclusion Wide expression of HHLA2 in human malignancies, association with poor prognostic factors and its T cell coinhibitory capability, suggests that the HHLA2 pathway represents a novel immunosuppressive mechanism within the tumor microenvironment and an attractive target for human cancer therapy. PMID

  2. LIG Family Receptor Tyrosine Kinase-Associated Proteins Modulate Growth Factor Signals During Neural Development

    PubMed Central

    Mandai, Kenji; Guo, Ting; Hillaire, Coryse St.; Meabon, James S.; Kanning, Kevin C.; Bothwell, Mark; Ginty, David D.

    2009-01-01

    SUMMARY Genome-wide screens were performed to identify transmembrane proteins that mediate axonal growth, guidance and target field innervation of somatosensory neurons. One gene, Linx (alias Islr2), encoding a leucine-rich repeat and immunoglobulin (LIG) family protein, is expressed in a subset of developing sensory and motor neurons. Domain and genomic structures of Linx and other LIG family members suggest that they are evolutionarily related to Trk receptor tyrosine kinases (RTKs). Several LIGs, including Linx are expressed in subsets of somatosensory and motor neurons and select members interact with TrkA and Ret RTKs. Moreover, axonal projection defects in mice harboring a null mutation in Linx resemble those in mice lacking Ngf, TrkA and Ret. In addition, Linx modulates NGF–TrkA- and GDNF–GFRα1/Ret-mediated axonal extension in cultured sensory and motor neurons, respectively. These findings show that LIGs physically interact with RTKs and modulate their activities to control axonal extension, guidance and branching. PMID:19755105

  3. Mutational analysis of the androgen receptor gene in two Indian families with partial androgen insensitivity syndrome.

    PubMed

    Nagaraja, M R; Rastogi, Amit; Raman, Rajiva; Gupta, Dinesh K; Singh, S K

    2009-12-01

    Mutation in the androgen receptor gene (AR) is known to cause androgen insensitivity syndrome (AIS). In an X-linked recessive manner, an AR mutation gets transmitted to the offspring through carrier mothers in 70% of cases, the other 30% arising de novo. However, reports on AR mutations amongst Indian patients with AIS are scarce in the literature. This study reports mutations in AR from two Indian families, each having a proband with partial androgen insensitivity syndrome (PAIS) phenotype. Clinical, endocrine and cytogenetic evaluation of these affected children was performed. Mutational analysis was carried out by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis followed by sequencing. The two point mutations were in exon 5: p.M742I, familial in patient 1 and p.V746M de novo in patient 2. These are hitherto unrecognized mutations in our population. Similar mutational studies are suggested in patients with AIS, in order to identify their frequency and clinical severity in our population.

  4. LIG family receptor tyrosine kinase-associated proteins modulate growth factor signals during neural development.

    PubMed

    Mandai, Kenji; Guo, Ting; St Hillaire, Coryse; Meabon, James S; Kanning, Kevin C; Bothwell, Mark; Ginty, David D

    2009-09-10

    Genome-wide screens were performed to identify transmembrane proteins that mediate axonal growth, guidance and target field innervation of somatosensory neurons. One gene, Linx (alias Islr2), encoding a leucine-rich repeat and immunoglobulin (LIG) family protein, is expressed in a subset of developing sensory and motor neurons. Domain and genomic structures of Linx and other LIG family members suggest that they are evolutionarily related to Trk receptor tyrosine kinases (RTKs). Several LIGs, including Linx, are expressed in subsets of somatosensory and motor neurons, and select members interact with TrkA and Ret RTKs. Moreover, axonal projection defects in mice harboring a null mutation in Linx resemble those in mice lacking Ngf, TrkA, and Ret. In addition, Linx modulates NGF-TrkA- and GDNF-GFRalpha1/Ret-mediated axonal extension in cultured sensory and motor neurons, respectively. These findings show that LIGs physically interact with RTKs and modulate their activities to control axonal extension, guidance and branching.

  5. The p160/steroid receptor coactivator family: potent arbiters of uterine physiology and dysfunction.

    PubMed

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

    2014-11-01

    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 uterine

  6. Insight into pattern of codon biasness and nucleotide base usage in serotonin receptor gene family from different mammalian species.

    PubMed

    Dass, J Febin Prabhu; Sudandiradoss, C

    2012-07-15

    5-HT (5-Hydroxy-tryptamine) or serotonin receptors are found both in central and peripheral nervous system as well as in non-neuronal tissues. In the animal and human nervous system, serotonin produces various functional effects through a variety of membrane bound receptors. In this study, we focus on 5-HT receptor family from different mammals and examined the factors that account for codon and nucleotide usage variation. A total of 110 homologous coding sequences from 11 different mammalian species were analyzed using relative synonymous codon usage (RSCU), correspondence analysis (COA) and hierarchical cluster analysis together with nucleotide base usage frequency of chemically similar amino acid codons. The mean effective number of codon (ENc) value of 37.06 for 5-HT(6) shows very high codon bias within the family and may be due to high selective translational efficiency. The COA and Spearman's rank correlation reveals that the nucleotide compositional mutation bias as the major factors influencing the codon usage in serotonin receptor genes. The hierarchical cluster analysis suggests that gene function is another dominant factor that affects the codon usage bias, while species is a minor factor. Nucleotide base usage was reported using Goldman, Engelman, Stietz (GES) scale reveals the presence of high uracil (>45%) content at functionally important hydrophobic regions. Our in silico approach will certainly help for further investigations on critical inference on evolution, structure, function and gene expression aspects of 5-HT receptors family which are potential antipsychotic drug targets.

  7. Interactions between the S-Domain Receptor Kinases and AtPUB-ARM E3 Ubiquitin Ligases Suggest a Conserved Signaling Pathway in Arabidopsis1[W][OA

    PubMed Central

    Samuel, Marcus A.; Mudgil, Yashwanti; Salt, Jennifer N.; Delmas, Frédéric; Ramachandran, Shaliny; Chilelli, Andrea; Goring, Daphne R.

    2008-01-01

    The Arabidopsis (Arabidopsis thaliana) genome encompasses multiple receptor kinase families with highly variable extracellular domains. Despite their large numbers, the various ligands and the downstream interacting partners for these kinases have been deciphered only for a few members. One such member, the S-receptor kinase, is known to mediate the self-incompatibility (SI) response in Brassica. S-receptor kinase has been shown to interact and phosphorylate a U-box/ARM-repeat-containing E3 ligase, ARC1, which, in turn, acts as a positive regulator of the SI response. In an effort to identify conserved signaling pathways in Arabidopsis, we performed yeast two-hybrid analyses of various S-domain receptor kinase family members with representative Arabidopsis plant U-box/ARM-repeat (AtPUB-ARM) E3 ligases. The kinase domains from S-domain receptor kinases were found to interact with ARM-repeat domains from AtPUB-ARM proteins. These kinase domains, along with M-locus protein kinase, a positive regulator of SI response, were also able to phosphorylate the ARM-repeat domains in in vitro phosphorylation assays. Subcellular localization patterns were investigated using transient expression assays in tobacco (Nicotiana tabacum) BY-2 cells and changes were detected in the presence of interacting kinases. Finally, potential links to the involvement of these interacting modules to the hormone abscisic acid (ABA) were investigated. Interestingly, AtPUB9 displayed redistribution to the plasma membrane of BY-2 cells when either treated with ABA or coexpressed with the active kinase domain of ARK1. As well, T-DNA insertion mutants for ARK1 and AtPUB9 lines were altered in their ABA sensitivity during germination and acted at or upstream of ABI3, indicating potential involvement of these proteins in ABA responses. PMID:18552232

  8. 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

  9. Abscisic acid metabolizing rhizobacteria decrease ABA concentrations in planta and alter plant growth.

    PubMed

    Belimov, Andrey A; Dodd, Ian C; Safronova, Vera I; Dumova, Valentina A; Shaposhnikov, Alexander I; Ladatko, Alexander G; Davies, William J

    2014-01-01

    Although endogenous phytohormones such as abscisic acid (ABA) regulate root growth, and many rhizobacteria can modulate root phytohormone status, hitherto there have been no reports of rhizobacteria mediating root ABA concentrations and growth by metabolising ABA. Using a selective ABA-supplemented medium, two bacterial strains were isolated from the rhizosphere of rice (Oryza sativa) seedlings grown in sod-podzolic soil and assigned to Rhodococcus sp. P1Y and Novosphingobium sp. P6W using partial 16S rRNA gene sequencing and phenotypic patterns by the GEN III MicroPlate test. Although strain P6W had more rapid growth in ABA-supplemented media than strain P1Y, both could utilize ABA as a sole carbon source in batch culture. When rice seeds were germinated on filter paper in association with bacteria, root ABA concentration was not affected, but shoot ABA concentration of inoculated plants decreased by 14% (strain P6W) and 22% (strain P1Y). When tomato (Solanum lycopersicum) genotypes differing in ABA biosynthesis (ABA deficient mutants flacca - flc, and notabilis - not and the wild-type cv. Ailsa Craig, WT) were grown in gnotobiotic cultures on nutrient solution agar, rhizobacterial inoculation decreased root and/or leaf ABA concentrations, depending on plant and bacteria genotypes. Strain P6W inhibited primary root elongation of all genotypes, but increased leaf biomass of WT plants. In WT plants treated with silver ions that inhibit ethylene perception, both ABA-metabolising strains significantly decreased root ABA concentration, and strain P6W decreased leaf ABA concentration. Since these changes in ABA status also occurred in plants that were not treated with silver, it suggests that ethylene was probably not involved in regulating bacteria-mediated changes in ABA concentration. Correlations between plant growth and ABA concentrations in planta suggest that ABA-metabolising rhizobacteria may stimulate growth via an ABA-dependent mechanism.

  10. The GM-CSF/IL-3/IL-5 cytokine receptor family: from ligand recognition to initiation of signaling.

    PubMed

    Broughton, Sophie E; Dhagat, Urmi; Hercus, Timothy R; Nero, Tracy L; Grimbaldeston, Michele A; Bonder, Claudine S; Lopez, Angel F; Parker, Michael W

    2012-11-01

    Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 are members of a discrete family of cytokines that regulates the growth, differentiation, migration and effector function activities of many hematopoietic cells and immunocytes. These cytokines are involved in normal responses to infectious agents, bridging innate and adaptive immunity. However, in certain cases, the overexpression of these cytokines or their receptors can lead to excessive or aberrant initiation of signaling resulting in pathological conditions, with chronic inflammatory diseases and myeloid leukemias the most notable examples. Recent crystal structures of the GM-CSF receptor ternary complex and the IL-5 binary complex have revealed new paradigms of cytokine receptor activation. Together with a wealth of associated structure-function studies, they have significantly enhanced our understanding of how these receptors recognize cytokines and initiate signals across cell membranes. Importantly, these structures provide opportunities for structure-based approaches for the discovery of novel and disease-specific therapeutics. In addition, recent biochemical evidence has suggested that the GM-CSF/IL-3/IL-5 receptor family is capable of interacting productively with other membrane proteins at the cell surface. Such interactions may afford additional or unique biological activities and might be harnessed for selective modulation of the function of these receptors in disease.

  11. Chromosomal localization of glutamate receptor genes: relationship to familial amyotrophic lateral sclerosis and other neurological disorders of mice and humans.

    PubMed Central

    Gregor, P; Reeves, R H; Jabs, E W; Yang, X; Dackowski, W; Rochelle, J M; Brown, R H; Haines, J L; O'Hara, B F; Uhl, G R

    1993-01-01

    Receptors for the major excitatory neurotransmitter glutamate may play key roles in neurodegeneration. The mouse Glur-5 gene maps to chromosome 16 between App and Sod-1. The homologous human GLUR5 gene maps to the corresponding region of human chromosome 21, which contains the locus for familial amyotrophic lateral sclerosis. This location, and other features, render GLUR5 a possible candidate gene for familial amyotrophic lateral sclerosis. In addition, dosage imbalance of GLUR5 may have a role in the trisomy 21 (Down syndrome). Further characterization of the murine glutamate receptor family includes mapping of Glur-1 to the same region as neurological mutants spasmodic, shaker-2, tipsy, and vibrator on chromosome 11; Glur-2 near spastic on chromosome 3; Glur-6 near waltzer and Jackson circler on chromosome 10; and Glur-7 near clasper on chromosome 4. Images Fig. 3 PMID:8464923

  12. The Role and Regulation of ABI5 (ABA-Insensitive 5) in Plant Development, Abiotic Stress Responses and Phytohormone Crosstalk

    PubMed Central

    Skubacz, Anna; Daszkowska-Golec, Agata; Szarejko, Iwona

    2016-01-01

    ABA Insensitive 5 (ABI5) is a basic leucine zipper transcription factor that plays a key role in the regulation of seed germination and early seedling growth in the presence of ABA and abiotic stresses. ABI5 functions in the core ABA signaling, which is composed of PYR/PYL/RCAR receptors, PP2C phosphatases and SnRK2 kinases, through the regulation of the expression of genes that contain the ABSCISIC ACID RESPONSE ELEMENT (ABRE) motif within their promoter region. The regulated targets include stress adaptation genes, e.g., LEA proteins. However, the expression and activation of ABI5 is not only dependent on the core ABA signaling. Many transcription factors such as ABI3, ABI4, MYB7 and WRKYs play either a positive or a negative role in the regulation of ABI5 expression. Additionally, the stability and activity of ABI5 are also regulated by other proteins through post-translational modifications such as phosphorylation, ubiquitination, sumoylation and S-nitrosylation. Moreover, ABI5 also acts as an ABA and other phytohormone signaling integrator. Components of auxin, cytokinin, gibberellic acid, jasmonate and brassinosteroid signaling and metabolism pathways were shown to take part in ABI5 regulation and/or to be regulated by ABI5. Monocot orthologs of AtABI5 have been identified. Although their roles in the molecular and physiological adaptations during abiotic stress have been elucidated, knowledge about their detailed action still remains elusive. Here, we describe the recent advances in understanding the action of ABI5 in early developmental processes and the adaptation of plants to unfavorable environmental conditions. We also focus on ABI5 relation to other phytohormones in the abiotic stress response of plants. PMID:28018412

  13. 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

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

    PubMed

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

    2013-09-01

    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.

  15. 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.

  16. 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

  17. Molecular cloning and characterization of the ABA-specific glucosyltransferase gene from bean (Phaseolus vulgaris L.).

    PubMed

    Palaniyandi, Sasikumar Arunachalam; Chung, Gyuhwa; Kim, Sang Hyon; Yang, Seung Hwan

    2015-04-15

    Levels of the plant hormone abscisic acid (ABA) are maintained in homeostasis by a balance of its biosynthesis, catabolism and conjugation. The detailed molecular and signaling events leading to strict homeostasis are not completely understood in crop plants. In this study, we obtained cDNA of an ABA-inducible, ABA-specific UDP-glucosyltransferase (ABAGT) from the bean plant (Phaseolus vulgaris L.) involved in conjugation of a glucose residue to ABA to form inactive ABA-glucose ester (ABA-GE) to examine its role during development and abiotic stress in bean. The bacterially expressed PvABAGTase enzyme showed ABA-specific glucosylation activity in vitro. A higher level of the PvABAGT transcript was observed in mature leaves, mature flowers, roots, seed coats and embryos as well as upon rehydration following a period of dehydration. Overexpression of 35S::PvABAGT in Arabidopsis showed reduced sensitivity to ABA compared with WT. The transgenic plants showed a high level of ABA-GE without significant decrease in the level of ABA compared with the wild type (WT) during dehydration stress. Upon rehydration, the levels of ABA and phaseic acid (PA) decreased in the WT and the PvABAGT-overexpressing lines with high levels of ABA-GE only in the transgenic plants. Our findings suggest that the PvABAGT gene could play a role in ABA homeostasis during development and stress responses in bean and its overexpression in Arabidopsis did not alter ABA homeostasis during dehydration stress.

  18. Expression and clinical significance of erb-B receptor family in hepatocellular carcinoma

    PubMed Central

    Ito, Y; Takeda, T; Sakon, M; Tsujimoto, M; Higashiyama, S; Noda, K; Miyoshi, E; Monden, M; Matsuura, N

    2001-01-01

    In order to elucidate the clinical significance of the erbB family, epidermal growth factor receptor (EGF-R), c-erbB-2, c-erbB-3 and c-erbB-4 in hepatocellular carcinoma (HCC), we investigated the expression of these proteins by means of immunohistochemistry for HCC as well as adjacent noncancerous lesions. EGF-R was expressed in 68% of the HCC examined and showed correlation with the proliferating activity, stage, intrahepatic metastasis and carcinoma differentiation. c-erbB-2 was expressed in only 21% of the cases and showed no relationships with the clinicopathological parameters. c-erbB-3 protein was observed in 84% of the HCC and 38.1% of the noncancerous lesions. Its expression in HCC was equal to or greater than noncancerous lesions in 90.5% of the cases, and was related to the stage, portal invasion, cell proliferating activity, tumour size, intrahepatic metastasis and carcinoma differentiation. c-erbB-4 protein was expressed in 61.0% of HCC and in as much as 86.1% of the noncancerous lesions. Unlike the expression of c-erbB-3, that of c-erbB-4 in HCC was less than that of the adjacent noncancerous lesions in 51.2% of the cases. No statistical significance could be established between this protein expression in HCC and clinicopathological features. EGF-R and c-erbB-3 affected disease-free survival, but were not recognized as independent prognostic factors by multivariate analysis. The present study suggests that, of the four receptors, EGF-R and c-erbB-3 play important roles in the progression of HCC. © 2001 Cancer Research Campaign www.bjcancer.com PMID:11355950

  19. Familial glucocorticoid resistance caused by a splice site deletion in the human glucocorticoid receptor gene

    SciTech Connect

    Karl, M.; Lamberts, S.W.J.; Detera-Wadleigh, S.D.; Encio, I.J.; Stratakis, C.A.; Hurley, D.M.; Accili, D.; Chrousos, G.P. Erasmus Univ. of Rotterdam )

    1993-03-01

    The clinical syndrome of generalized, compensated glucocorticoid resistance is characterized by increased cortisol secretion without clinical evidence of hyper- or hypocortisolism, and manifestations of androgen and/or mineralocorticoid excess. This condition results from partial failure of the glucocorticoid receptor (GR) to modulate transcription of its target genes. The authors studied the molecular mechanisms of this syndrome in a Dutch kindred, whose affected members had hypercortisolism and approximately half of normal GRs, and whose proband was a young woman with manifestations of hyperandrogenism. Using the polymerase chain reaction to amplify and sequence each of the nine exons of the GR gene [alpha], along with their 5[prime]- and 3[prime]-flanking regions, the authors identified a 4-base deletion at the 3[prime]-boundary of exon 6 in one GR allele ([Delta][sub 4]), which removed a donor splice site in all three affected members studied. In contrast, the sequence of exon 6 in the two unaffected siblings was normal. A single nucleotide substitution causing an amino acid substitution in the amino terminal domain of the GR (asparagine to serine, codon 363) was also discovered in exon 2 of the other allele (G[sub 1220]) in the proband, in one of her affected brothers and in her unaffected sister. This deletion in the glucocorticoid receptor gene was associated with the expression of only one allele and a decrease of GR protein by 50% in affected members of this glucocorticoid resistant family. The mutation identified in exon 2 did not segregate with the disease and appears to be of no functional significance. The presence of the null allele was apparently compensated for by increased cortisol production at the expense of concurrent hyperandrogenism. 40 refs., 3 figs.

  20. 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.

  1. 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.

  2. miRNAome analysis of the mammalian neuronal nicotinic acetylcholine receptor gene family.

    PubMed

    Hogan, Eric M; Casserly, Alison P; Scofield, Michael D; Mou, Zhongming; Zhao-Shea, Rubing; Johnson, Chris W; Tapper, Andrew R; Gardner, Paul D

    2014-12-01

    Nicotine binds to and activates a family of ligand-gated ion channels, neuronal nicotinic acetylcholine receptors (nAChRs). Chronic nicotine exposure alters the expression of various nAChR subtypes, which likely contributes to nicotine dependence; however, the underlying mechanisms regulating these changes remain unclear. A growing body of evidence indicates that microRNAs (miRNAs) may be involved in nAChR regulation. Using bioinformatics, miRNA library screening, site-directed mutagenesis, and gene expression analysis, we have identified a limited number of miRNAs that functionally interact with the 3'-untranslated regions (3' UTRs) of mammalian neuronal nAChR subunit genes. In silico analyses revealed specific, evolutionarily conserved sites within the 3' UTRs through which the miRNAs regulate gene expression. Mutating these sites disrupted miRNA regulation confirming the in silico predictions. In addition, the miRNAs that target nAChR 3' UTRs are expressed in mouse brain and are regulated by chronic nicotine exposure. Furthermore, we show that expression of one of these miRNAs, miR-542-3p, is modulated by nicotine within the mesocorticolimbic reward pathway. Importantly, overexpression of miR-542-3p led to a decrease in the protein levels of its target, the nAChR β2 subunit. Bioinformatic analysis suggests that a number of the miRNAs play a general role in regulating cholinergic signaling. Our results provide evidence for a novel mode of nicotine-mediated regulation of the mammalian nAChR gene family.

  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. 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.

  5. 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.

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

    PubMed Central

    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

    2016-01-01

    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

  7. Characterization of myelin ligand complexes with neuronal Nogo-66 receptor family members.

    PubMed

    Laurén, Juha; Hu, Fenghua; Chin, Joanna; Liao, Ji; Airaksinen, Matti S; Strittmatter, Stephen M

    2007-02-23

    Nogo, MAG, and OMgp are myelin-associated proteins that bind to a neuronal Nogo-66 receptor (NgR/NgR1) to limit axonal regeneration after central nervous system injury. Within Nogo-A, two separate domains are known interact with NgR1. NgR1 is the founding member of the three-member NgR family, whereas Nogo-A (RTN4A) belongs to a four-member reticulon family. Here, we systematically mapped the interactions between these superfamilies, demonstrating novel nanomolar interactions of RTN2 and RTN3 with NgR1. Because RTN3 is expressed in spinal cord white matter, it may have a role in myelin inhibition of axonal growth. Further analysis of the Nogo-A and NgR1 interactions revealed a novel third interaction site between the proteins, suggesting a trivalent Nogo-A interaction with NgR1. We also confirmed here that MAG binds to NgR2, but not to NgR3. Unexpectedly, we found that OMgp interacts with MAG with a higher affinity compared with NgR1. To better define how these multiple structurally distinct ligands bind to NgR1, we examined a series of Ala-substituted NgR1 mutants for ligand binding activity. We found that the core of the binding domain is centered in the middle of the concave surface of the NgR1 leucine-rich repeat domain and surrounded by differentially utilized residues. This detailed knowledge of the molecular interactions between NgR1 and its ligands is imperative when assessing options for development of NgR1-based therapeutics for central nervous system injuries.

  8. 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

  9. 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.

  10. 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.

  11. Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families.

    PubMed

    Patten, Glen S; Abeywardena, Mahinda Y; Bennett, Louise E

    2016-01-01

    Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

  12. 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

  13. Assessment battery for communication (ABaCo): normative data.

    PubMed

    Angeleri, Romina; Bosco, Francesca M; Gabbatore, Ilaria; Bara, Bruno G; Sacco, Katiuscia

    2012-09-01

    The Assessment Battery for Communication (ABaCo) was introduced to evaluate pragmatic abilities in patients with cerebral lesions. The battery is organized into five evaluation scales focusing on separate components of pragmatic competence. In the present study, we present normative data for individuals 15-75 years of age (N = 300). The sample was stratified by age, sex, and years of education, according to Italian National Institute of Statistics indications in order to be representative of the general national population. Since performance on the ABaCo decreases with age and lower years of education, the norms were stratified for both age and education. The ABaCo is a valuable tool in clinical practice; the normative data provided here will enable clinicians to determine different kinds and specific levels of communicative impairments more precisely.

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

    PubMed Central

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

    2016-01-01

    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

  15. A family of plasmodesmal proteins with receptor-like properties for plant viral movement proteins.

    PubMed

    Amari, Khalid; Boutant, Emmanuel; Hofmann, Christina; Schmitt-Keichinger, Corinne; Fernandez-Calvino, Lourdes; Didier, Pascal; Lerich, Alexander; Mutterer, Jérome; Thomas, Carole L; Heinlein, Manfred; Mély, Yves; Maule, Andrew J; Ritzenthaler, Christophe

    2010-09-23

    Plasmodesmata (PD) are essential but poorly understood structures in plant cell walls that provide symplastic continuity and intercellular communication pathways between adjacent cells and thus play fundamental roles in development and pathogenesis. Viruses encode movement proteins (MPs) that modify these tightly regulated pores to facilitate their spread from cell to cell. The most striking of these modifications is observed for groups of viruses whose MPs form tubules that assemble in PDs and through which virions are transported to neighbouring cells. The nature of the molecular interactions between viral MPs and PD components and their role in viral movement has remained essentially unknown. Here, we show that the family of PD-located proteins (PDLPs) promotes the movement of viruses that use tubule-guided movement by interacting redundantly with tubule-forming MPs within PDs. Genetic disruption of this interaction leads to reduced tubule formation, delayed infection and attenuated symptoms. Our results implicate PDLPs as PD proteins with receptor-like properties involved the assembly of viral MPs into tubules to promote viral movement.

  16. Amyloid Precursor Protein family as unconventional Go-coupled receptors and the control of neuronal motility.

    PubMed

    Ramaker, Jenna M; Copenhaver, Philip F

    2017-01-01

    Cleavage of the Amyloid Precursor Protein (APP) generates amyloid peptides that accumulate in Alzheimer Disease (AD), but APP is also upregulated by developing and injured neurons, suggesting that it regulates neuronal motility. APP can also function as a G protein-coupled receptor that signals via the heterotrimeric G protein Gαo, but evidence for APP-Gαo signaling in vivo has been lacking. Using Manduca as a model system, we showed that insect APP (APPL) regulates neuronal migration in a Gαo-dependent manner. Recently, we also demonstrated that Manduca Contactin (expressed by glial cells) induces APPL-Gαo retraction responses in migratory neurons, consistent with evidence that mammalian Contactins also interact with APP family members. Preliminary studies using cultured hippocampal neurons suggest that APP-Gαo signaling can similarly regulate growth cone motility. Whether Contactins (or other APP ligands) induce this response within the developing nervous system, and how this pathway is disrupted in AD, remains to be explored.

  17. Inhibiting EGF receptor or SRC family kinase signaling overcomes BRAF inhibitor resistance in melanoma

    PubMed Central

    Girotti, Maria R; Pedersen, Malin; Sanchez-Laorden, Berta; Viros, Amaya; Turajlic, Samra; Niculescu-Duvaz, Dan; Zambon, Alfonso; Sinclair, John; Hayes, Andrew; Gore, Martin; Lorigan, Paul; Springer, Caroline; Larkin, James; Jorgensen, Claus; Marais, Richard

    2017-01-01

    We generated cell lines resistant to BRAF inhibitors and show that the EGF receptor (EGFR)–SRC family kinase (SFK)–STAT3 signaling pathway was upregulated in these cells. In addition to driving proliferation of resistant cells, this pathway also stimulated invasion and metastasis. EGFR inhibitors cooperated with BRAF inhibitors to block the growth of the resistant cells in vitro and in vivo, and monotherapy with the broad specificity tyrosine kinase inhibitor dasatinib blocked growth and metastasis in vivo. We analyzed tumors from patients with intrinsic or acquired resistance to vemurafenib and observed increased EGFR and SFK activity. Furthermore, dasatinib blocked the growth and metastasis of one of the resistant tumors in immunocompromised mice. Our data shows that BRAF inhibitor-mediated activation of EFGR/SFK/STAT3 signaling can mediate resistance in BRAF mutant melanoma patients. We describe two treatments that appear to overcome this resistance and could deliver therapeutic efficacy in drug-resistant BRAF mutant melanoma patients. PMID:23242808

  18. 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

  19. 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.

  20. 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

  1. The NAC-type transcription factor OsNAC2 regulates ABA-dependent genes and abiotic stress tolerance in rice

    PubMed Central

    Shen, Jiabin; Lv, Bo; Luo, Liqiong; He, Jianmei; Mao, Chanjuan; Xi, Dandan; Ming, Feng

    2017-01-01

    Plants can perceive environmental changes and respond to external stressors. Here, we show that OsNAC2, a member of the NAC transcription factor family, was strongly induced by ABA and osmotic stressors such as drought and high salt. With reduced yields under drought conditions at the flowering stage, OsNAC2 overexpression lines had lower resistance to high salt and drought conditions. RNAi plants showed enhanced tolerance to high salinity and drought stress at both the vegetative and flowering stages. Furthermore, RNAi plants had improved yields after drought stress. A microarray assay indicated that many ABA-dependent stress-related genes were down-regulated in OsNAC2 overexpression lines. We further confirmed that OsNAC2 directly binds the promoters of LATE EMBRYOGENESIS ABUNDANT 3 (OsLEA3) and Stress-Activated Protein Kinases 1 (OsSAPK1), two marker genes in the abiotic stress and ABA response pathways, respectively. Our results suggest that in rice OsNAC2 regulates both abiotic stress responses and ABA-mediated responses, and acts at the junction between the ABA and abiotic stress pathways. PMID:28074873

  2. 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.

  3. A family of MHC class I-like genes located in the vicinity of the mouse leukocyte receptor complex

    PubMed Central

    Kasahara, Masanori; Watanabe, Yutaka; Sumasu, Motoko; Nagata, Taeko

    2002-01-01

    Some members of the major histocompatibility complex (MHC) class I gene family are encoded outside the MHC. Here we describe a family of mouse class I-like genes mapping to the vicinity of the leukocyte receptor complex (LRC) on chromosome 7. This family, which we call Mill (MHC class I-like located near the LRC), has two members designated Mill1 and Mill2. Both genes are predicted to encode membrane glycoproteins with domain organization essentially similar to that of MHC class I heavy chains. The following features of Mill are noteworthy. (i) The deduced MILL proteins lack most of the residues known to be involved in the docking of peptides in classical MHC class I molecules. (ii) Among the known members of the class I gene family, MILL1 and MILL2 are related most closely to MICA/MICB encoded in the human MHC. (iii) Unlike all other known members of the class I gene family, Mill1 and Mill2 have an exon between those coding for the signal peptide and the α1 domain. (iv) Mill1 has a more restricted expression profile than Mill2. (v) The gene orthologous to Mill1 or Mill2 apparently is absent in the human. (vi) Mill1 and Mill2 show a limited degree of polymorphism in laboratory mice. The observation that the Mill family is related most closely to the MIC family, together with its apparent absence in the human, suggests its involvement in innate immunity. PMID:12370446

  4. 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.

  5. Improved cold tolerance in Elymus nutans by exogenous application of melatonin may involve ABA-dependent and ABA-independent pathways

    PubMed Central

    Fu, Juanjuan; Wu, Ye; Miao, Yanjun; Xu, Yamei; Zhao, Enhua; Wang, Jin; Sun, Huaien; Liu, Qian; Xue, Yongwei; Xu, Yuefei; Hu, Tianming

    2017-01-01

    Melatonin is an important secondary messenger that plays a central role in plant growth, as well as abiotic and biotic stress tolerance. However, the underlying physiological and molecular mechanisms of melatonin-mediated cold tolerance, especially interactions between melatonin and other key molecules in the plant stress response, remain unknown. Here, the interrelation between melatonin and abscisic acid (ABA) was investigated in two genotypes of Elymus nutans Griseb., the cold-tolerant Damxung (DX) and the cold-sensitive Gannan (GN) under cold stress. Pre-treatment with exogenous melatonin or ABA alleviated oxidative injury via scavenging ROS, while enhancing both antioxidant enzyme activities and non-enzymatic antioxidant contents. Treatment of fluridone, an ABA biosynthesis inhibitor caused membrane lipid peroxidation and lowered melatonin-induced antioxidant defense responses. It is worth noting that cold stress significantly induced both endogenous melatonin and ABA levels in both genotypes. Application of melatonin increased ABA production, while fluridone significantly suppressed melatonin-induced ABA accumulation. ABA and fluridone pre-treatments failed to affect the endogenous melatonin concentration. Moreover, exogenous melatonin up-regulated the expression of cold-responsive genes in an ABA-independent manner. These results indicate that both ABA-dependent and ABA-independent pathways may contribute to melatonin-induced cold tolerance in E. nutans. PMID:28045095

  6. The Adam family metalloprotease Kuzbanian regulates the cleavage of the roundabout receptor to control axon repulsion at the midline.

    PubMed

    Coleman, Hope A; Labrador, Juan-Pablo; Chance, Rebecca K; Bashaw, Greg J

    2010-07-01

    Slits and their Roundabout (Robo) receptors mediate repulsive axon guidance at the Drosophila ventral midline and in the vertebrate spinal cord. Slit is cleaved to produce fragments with distinct signaling properties. In a screen for genes involved in Slit-Robo repulsion, we have identified the Adam family metalloprotease Kuzbanian (Kuz). Kuz does not regulate midline repulsion through cleavage of Slit, nor is Slit cleavage essential for repulsion. Instead, Kuz acts in neurons to regulate repulsion and Kuz can cleave the Robo extracellular domain in Drosophila cells. Genetic rescue experiments using an uncleavable form of Robo show that this receptor does not maintain normal repellent activity. Finally, Kuz activity is required for Robo to recruit its downstream signaling partner, Son of sevenless (Sos). These observations support the model that Kuz-directed cleavage is important for Robo receptor activation.

  7. Applied Behaviour Analysis: Does Intervention Intensity Relate to Family Stressors and Maternal Well-Being?

    ERIC Educational Resources Information Center

    Schwichtenberg, A.; Poehlmann, J.

    2007-01-01

    Background: Interventions based on applied behaviour analysis (ABA) are commonly recommended for children with an autism spectrum disorder (ASD); however, few studies address how this intervention model impacts families. The intense requirements that ABA programmes place on children and families are often cited as a critique of the programme,…

  8. Low-density lipoprotein receptor gene mutation analysis and structure-function correlation in an Omani arab family with familial hypercholesterolemia.

    PubMed

    Al-Rasadi, Khalid; Al-Waili, Khalid; Al-Zidi, Ward Al-Muna; Al-Abri, Abdul Rahim; Al-Hinai, Ali T; Al-Sabti, Hilal Ali; Al-Tobi, Sheikha; Al-Zakwani, Ibrahim; Al-Zadjali, Fahad; Al-Hashmi, Khamis; Banerjee, Yajnavalka

    2014-11-01

    Familial hypercholesterolemia (FH) is an autosomal dominant disorder typified by elevated low-density lipoprotein cholesterol (LDL-C) levels caused by mutations in the LDL receptor (LDLR), apolipoprotein B (ApoB), or proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Previously, we reported a novel mutation in the exon-3 of LDLR gene, observed in a 9-year-old Omani Arab female. Here, we investigated the mode of inheritance of this mutation and confirmed that FH in this family is due to mutation only in the LDLR and not PCSK9 and ApoB genes. Further, the effect of the mutation has been appraised in silico on the tertiary structure of LDLR. A model of the mutant LDLR has been constructed using the coordinates of the wild-type LDLR extracellular domain. Based on the model, we present a mechanistic justification behind the observed detrimental effect of the mutation on LDL-C levels.

  9. 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.

  10. 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.

  11. 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.

    PubMed

    Tsigos, C; Arai, K; Latronico, A C; DiGeorge, A M; Rapaport, R; Chrousos, G P

    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 families with triple A syndrome. The proband with IGD was a homozygote for an A-->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.

  12. Mutant p53 amplifies Epidermal Growth Factor Receptor family signaling to promote mammary tumorigenesis

    PubMed Central

    Yallowitz, Alisha; Li, Dun; Lobko, Antony; Nemajerova, Alice; Marchenko, Natalia

    2016-01-01

    The epidermal growth factor receptor family (ErbB2/Her2 and EGFR/ErbB1/Her1) often modulates the transcriptional program involved in promoting mammary tumorigenesis. In humans, more than 70% of ErbB2-positive sporadic breast cancers harbor p53 mutations, which correlate with poor prognosis. Also, the extremely high incidence of ErbB2-positive breast cancer in women with p53 germ-line mutations (Li-Fraumeni Syndrome) suggests the key role of mutant p53 specifically in ErbB2-mediated mammary tumorigenesis. To examine the role of mutant p53 during ErbB2-mediated mammary tumorigenesis we introduced a mutant p53 R172H allele into a (MMTV)-ErbB2/Neu mouse model. We show in heterozygous p53 mice that mutp53 R172H is a more potent activator of ErbB2-mediated mammary tumorigenesis than simple loss of p53. The more aggressive disease in mutant p53 animals was reflected by earlier tumor onset, increased mammary tumor multiplicity, and shorter survival. We provide molecular evidence that mutant p53 amplifies ErbB2 and EGFR signaling to promote the expansion of mammary stem cells and induce cancer cell proliferation. This study therefore identifies mutant p53 as an essential player in ErbB2 and EGFR-mediated breast cancer and indicates the potential translational importance of targeting mutant p53 in this subset of breast cancer patients. PMID:25573952

  13. Investigating the role of ABA signaling in wheat drought tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Allohexaploid wheat (Triticum aestivum L.) is one of the three major cereal crops supporting human nutrition. Because wheat is often grown under dryland conditions, it is subject to losses as a result of drought stress. This study examines the role of the plant hormone ABA is wheat responses to wate...

  14. 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,…

  15. 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,…

  16. 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…

  17. 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…

  18. 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…

  19. Effects of high night temperature and abscisic acid (ABA) on rice (Oryza sativa L.) physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High night temperature (HNT) is known to decrease rice yields. The impact of abscisic acid (ABA) on plants has been the subject of many studies. However, little or no work has been carried out on rice response to ABA under HNT-stress conditions. This study determined the effects of ABA on rice leaf ...

  20. ABA and Instruction of Students with Autism Spectrum Disorders: Introduction to the Special Series.

    ERIC Educational Resources Information Center

    Heflin, L. Juane; Alberto, Paul A.

    2001-01-01

    This introductory article to this special issue on the use of applied behavior analysis (ABA) with autism spectrum disorders (ASD) notes the 40-year history of ABA strategy development, verification, and generalization. It briefly introduces the following articles, which are intended to illustrate the range of ABA applications and the depth of…

  1. 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…

  2. Family Economic Hardship, Corticotropin-Releasing Hormone Receptor Polymorphisms, and Depressive Symptoms in Rural African American Youths

    PubMed Central

    Chen, Yi-fu; Brody, Gene H.

    2015-01-01

    Purpose To use pooled data from 2 independent studies of rural African American youths to test the moderation effect of the corticotropin-releasing hormone receptor 1 gene (CRHR1) on the link between family economic hardship and trajectories of depressive symptoms. Methods Two longitudinal studies were conducted involving African Americans, 16 (N = 474) and 18 (N = 419) years of age, who were randomly recruited in rural Georgia. Family economic hardship and youths’ depressive symptoms were assessed 4 times across 2 1/2 years. Genetic data also were collected. Haplotype analysis was performed on single nucleotide polymorphisms of CRHR1; 2 haplotypes were aggregated to form a CRHR1 index. Growth curve models were executed to determine whether CRHR1 moderated the link between Wave 1 family economic hardship and youths’ development of depression. Results CRHR1 × family economic hardship interactions significantly predicted youths’ depressive symptoms. When exposed to family economic hardship 1 standard deviation above the mean at Wave 1, youths who scored 0 on the CRHR1 index showed high and increasing depressive symptoms across time, whereas those who scored 2 on the index showed a decrease in depressive symptoms. Conclusions The CRHR1 gene reduces the risk for depressive symptoms among youths living in families undergoing high levels of economic hardship. PMID:26206446

  3. 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

  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.

  5. A novel point mutation (R840S) in the androgen receptor in a Brazilian family with partial androgen insensitivity syndrome.

    PubMed

    Melo, K F; Latronico, A C; Costa, E M; Billerbeck, A E; Mendonca, B B; Arnhold, I J

    1999-10-01

    Mutations of the androgen receptor gene causing androgen insensitivity syndrome in 46, XY individuals, result in phenotypes ranging from complete female to ambiguous genitalia to males with minor degrees of undervirilization. We studied two Brazilian brothers with partial androgen insensitivity syndrome. They were born with perineal hypospadias, bifid scrotum, small penis and cryptorchidism, and developed gynecomastia at puberty. Genomic DNA was extracted and denaturinggradient gel electrophoresis of exon 7 of the androgen receptor gene followed by sequence analysis revealed a new mutation, a C A transversion, altering codon 840 from arginine (CGT) to serine (AGT). R840 is located in the androgen binding domain, in a "hot spot" region, important for the formation and function of the hormone receptor-complex and within the region that is involved in androgen receptor dimerization. Replacement of arginine (basic) by serine (neutral and polar) is a nonconservative substitution. Three mutations in this residue (R840C, R840G nonconservative and R840H, conservative) were previously reported in patients with partial androgen insensitivity syndrome and when expressed "in vitro" lead to a subnormal transactivation of a reporter gene. We conclude that the novel R840 mutation in the androgen receptor is the cause of partial androgen insensitivity syndrome in this Brazilian family.

  6. 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

  7. A new point mutation in the luteinising hormone receptor gene in familial and sporadic male limited precocious puberty: genotype does not always correlate with phenotype.

    PubMed Central

    Evans, B A; Bowen, D J; Smith, P J; Clayton, P E; Gregory, J W

    1996-01-01

    Genomic DNA from two families with male limited precocious puberty was examined for mutations of the LH receptor gene. In family 1, several members of the pedigree have FMPP, whereas in family 2 there is only one affected subject. A point mutation (T --> C at nucleotide 1192) resulting in substitution of threonine for methionine 398 in the second transmembrane domain of the LH receptor protein was found in both families. In addition, one member of family 1 has the mutation, but no evidence of precocious puberty. All obligate carriers within this family were shown to have the mutation, and it was not detected in 94 chromosomes from unaffected and unrelated white subjects. In family 2, the index case was the only one to have the mutation. A previously unreported neutral dimorphism (C --> T at nucleotide 1065) is also described. Images PMID:8929952

  8. 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.

  9. Molecular evolution of the toll-like receptor multigene family in birds.

    PubMed

    Alcaide, Miguel; Edwards, Scott V

    2011-05-01

    Toll-like receptors (TLR) are membrane-bound sensors of the innate immune system that recognize invariant and distinctive molecular features of invading microbes and are also essential for initiating adaptive immunity in vertebrates. The genetic variation at TLR genes has been directly related to differential pathogen outcomes in humans and livestock. Nonetheless, new insights about the impact of TLRs polymorphism on the evolutionary ecology of infectious diseases can be gained through the investigation of additional vertebrate groups not yet investigated in detail. In this study, we have conducted the first characterization of the entire TLR multigene family (N = 10 genes) in non-model avian species. Using primers targeting conserved coding regions, we aimed at amplifying large segments of the extracellular domains (275-435 aa) involved in pathogen recognition across seven phylogenetically diverse bird species. Our analyses suggest avian TLRs are dominated by stabilizing selection, suggesting that slow rates of nonsynonymous substitution help preserve biological function. Overall, mean values of ω (= d(n)/d(s)) at each TLR locus ranged from 0.196 to 0.517. However, we also found patterns of positive selection acting on specific amino acid sites that could be linked to species-specific differences in pathogen-associated molecular pattern recognition. Only 39 of 2,875 (∼1.35%) of the codons analyzed exhibited significant patterns of positive selection. At least one half of these positively selected codons can be mapped to putative ligand-binding regions, as suggested by crystallographic structures of TLRs and their ligands and mutagenic analyses. We also surveyed TLR polymorphism in wild populations of two bird species, the Lesser Kestrel Falco naumanni and the House Finch Carpodacus mexicanus. In general, avian TLRs displayed low to moderate single nucleotide polymorphism levels and an excess of silent nucleotide substitutions, but also conspicuous instances of

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

    PubMed Central

    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

  11. 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.

  12. Agonist selectivity in the oxytocin/vasopressin receptor family: new insights and challenges.

    PubMed

    Chini, B; Manning, M

    2007-08-01

    The design and development of selective agonists acting at the OT (oxytocin)/AVP (vasopressin) receptors has been and continues to be a difficult task because of the great similarity among the different receptor subtypes as well as the high degree of chemical similarity between the active ligands. In recent decades, at least a thousand synthetic peptides have been synthesized and examined for their ability to bind to and activate the different OT/AVP receptors; an effort that has led to the identification of several receptor subtype-selective agonists in the rat. However, owing to species differences between rat and human AVP/OT receptors, these peptides do not exhibit the same selectivities in human receptor assays. Furthermore, the discovery of receptor promiscuity, which is the ability of a single receptor subtype to couple to several different G-proteins, has led to the definition of a completely new class of compounds, referred to here as coupling-selective ligands, which may activate, within a single receptor subtype, only a specific signalling pathway. Finally, the accumulating evidence that GPCRs (G-protein-coupled receptors) do not function as monomers, but as dimers/oligomers, opens up the design of another class of specific ligands, bivalent ligands, in which two agonist and/or antagonist moieties are joined by a spacer of the appropriate length to allow the simultaneous binding at the two subunits within the dimer. The pharmacological properties and selectivity profiles of these bivalent ligands, which remain to be investigated, could lead to highly novel research tools and potential therapeutic agents.

  13. The aba mutant of Arabidopsis thaliana is impaired in epoxy-carotenoid biosynthesis

    SciTech Connect

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

    1991-09-01

    The three mutant alleles of the ABA locus of Arabidopsis thaliana result in plants that are deficient in the plant growth regulator abscisic acid (ABA). The authors have used {sup 18}O{sub 2} to label ABA in water-stressed leaves of mutant and wild-type Arabidopsis. Analysis by selected ion monitoring and tandem mass spectrometry of ({sup 18}O)ABA and its catabolites, phaseic acid and ABA-glucose ester ({beta}-D-glucopyranosyl abscisate), indicates that the aba genotypes are impaired in ABA biosynthesis and have a small ABA precursor pool of compounds that contain oxygens on the rings, presumably oxygenated carotenoids (xanthophylls). Quantitation of the carotenoids form mutant and wild-type leaves establishes that the aba alleles cause a deficiency of the epoxy-carotenoids violaxanthin and neoxanthin and an accumulation of their biosynthetic precursor, zeaxanthin. These results provide evidence that ABA is synthesized by oxidative cleavage of epoxy-carotenoids (the indirect pathway). Furthermore the carotenoid mutant they describe undergoes normal greening. Thus the aba alleles provide an opportunity to study the physiological roles of epoxy-carotenoids in photosynthesis in a higher plants.

  14. The Ethylene Receptors ETHYLENE RESPONSE1 and ETHYLENE RESPONSE2 Have Contrasting Roles in Seed Germination of Arabidopsis during Salt Stress1[W][OPEN

    PubMed Central

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

    2014-01-01

    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. PMID:24820022

  15. Reduced Accumulation of ABA during Water Stress in a Molybdenum Cofactor Mutant of Barley 1

    PubMed Central

    Walker-Simmons, Mary; Kudrna, David A.; Warner, Robert L.

    1989-01-01

    A barley (Hordeum vulgare L.) mutant (Az34) has been identified with low basal levels of abscisic acid (ABA) and with reduced capacity for producing ABA in response to water stress. The mutation is in a gene controlling the molybdenum cofactor resulting in a pleiotropic deficiency in at least three molybdoenzymes, nitrate reductase, xanthine dehydrogenase, and aldehyde oxidase. The mutant was found to lack aldehyde oxidase activity with several substrates including: (a) ABA aldehyde, a putative precursor of ABA; (b) an acetylenic analog of ABA aldehyde; and (c) heptaldehyde. Elevating the growth temperature from 18 to 26°C caused mutant leaves to wilt and brown. Desiccation of mutant leaves was prevented by applying ABA. These results indicate that ABA biosynthesis at some developmental stages is dependent upon a molybdoenzyme which may be an aldehyde oxidase. Images Figure 5 PMID:16666835

  16. Polymer-based cell-free expression of ligand-binding family B G-protein coupled receptors without detergents

    PubMed Central

    Klammt, Christian; Perrin, Marilyn H; Maslennikov, Innokentiy; Renault, Ludovic; Krupa, Martin; Kwiatkowski, Witek; Stahlberg, Henning; Vale, Wylie; Choe, Senyon

    2011-01-01

    G-protein coupled receptors (GPCRs) constitute the largest family of intercellular signaling molecules and are estimated to be the target of more than 50% of all modern drugs. As with most integral membrane proteins (IMPs), a major bottleneck in the structural and biochemical analysis of GPCRs is their expression by conventional expression systems. Cell-free (CF) expression provides a relatively new and powerful tool for obtaining preparative amounts of IMPs. However, in the case of GPCRs, insufficient homogeneity of the targeted protein is a problem as the in vitro expression is mainly done with detergents, in which aggregation and solubilization difficulties, as well as problems with proper folding of hydrophilic domains, are common. Here, we report that using CF expression with the help of a fructose-based polymer, NV10 polymer (NVoy), we obtained preparative amounts of homogeneous GPCRs from the three GPCR families. We demonstrate that two GPCR B family members, corticotrophin-releasing factor receptors 1 and 2β are not only solubilized in NVoy but also have functional ligand-binding characteristics with different agonists and antagonists in a detergent-free environment as well. Our findings open new possibilities for functional and structural studies of GPCRs and IMPs in general. PMID:21465615

  17. Arabidopsis CBL interacting protein kinase 3 interacts with ABR1, an APETALA2 domain transcription factor, to regulate ABA responses.

    PubMed

    Sanyal, Sibaji K; Kanwar, Poonam; Yadav, Akhilesh K; Sharma, Cheshta; Kumar, Ashish; Pandey, Girdhar K

    2017-01-01

    Calcium (Ca(2+)) plays a vital role as a second messenger in several signaling pathways in plants. The calcineurin B-like proteins (CBLs) represent a family of plant calcium-binding proteins that function in propagating Ca(2+) signals by interacting with CBL interacting protein kinases (CIPKs). Phosphorylation of CBL by CIPK is essential for the module to display full activity towards its target protein. Previous genetic analysis showed that the function of CBL9-CIPK3 module was implicated in negatively regulating seed germination and early development. In the present study, we have biochemically investigated the interaction of CBL9-CIPK3 module and our findings show that CBL9 is phosphorylated by CIPK3. Moreover, Abscisic acid repressor 1 (ABR1) is identified as the downstream target of CIPK3 and CIPK3-ABR1 function to regulate ABA responses during seed germination. Our study also indicates that the role of ABR1 is not limited to seed germination but it also regulates the ABA dependent processes in the adult stage of plant development. Combining our results, we conclude that the CBL9-CIPK3-ABR1 pathway functions to regulate seed germination and ABA dependent physiological processes in Arabidopsis.

  18. Modulation of abscisic acid signaling in vivo by an engineered receptor-insensitive protein phosphatase type 2C allele.

    PubMed

    Dupeux, Florine; Antoni, Regina; Betz, Katja; Santiago, Julia; Gonzalez-Guzman, Miguel; Rodriguez, Lesia; Rubio, Silvia; Park, Sang-Youl; Cutler, Sean R; Rodriguez, Pedro L; Márquez, José A

    2011-05-01

    The plant hormone abscisic acid (ABA) plays a crucial role in the control of the stress response and the regulation of plant growth and development. ABA binding to PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS intracellular receptors leads to inhibition of key negative regulators of ABA signaling, i.e. clade A protein phosphatases type 2C (PP2Cs) such as ABA-INSENSITIVE1 and HYPERSENSITIVE TO ABA1 (HAB1), causing the activation of the ABA signaling pathway. To gain further understanding on the mechanism of hormone perception, PP2C inhibition, and its implications for ABA signaling, we have performed a structural and functional analysis of the PYR1-ABA-HAB1 complex. Based on structural data, we generated a gain-of-function mutation in a critical residue of the phosphatase, hab1(W385A), which abolished ABA-dependent receptor-mediated PP2C inhibition without impairing basal PP2C activity. As a result, hab1(W385A) caused constitutive inactivation of the protein kinase OST1 even in the presence of ABA and PYR/PYL proteins, in contrast to the receptor-sensitive HAB1, and therefore hab1(W385A) qualifies as a hypermorphic mutation. Expression of hab1(W385A) in Arabidopsis (Arabidopsis thaliana) plants leads to a strong, dominant ABA insensitivity, which demonstrates that this conserved tryptophan residue can be targeted for the generation of dominant clade A PP2C alleles. Moreover, our data highlight the critical role of molecular interactions mediated by tryptophan-385 equivalent residues for clade A PP2C function in vivo and the mechanism of ABA perception and signaling.

  19. On the origin of ion selectivity in the Cys-loop receptor family.

    PubMed

    Sine, Steven M; Wang, Hai-Long; Hansen, Scott; Taylor, Palmer

    2010-01-01

    Agonist binding to Cys-loop receptors promotes a large transmembrane ion flux of several million cations or anions per second. To investigate structural bases for the dynamics (MD) simulations, X-ray crystallography, and single channel recording. MD simulations of the muscle nicotinic receptor, imbedded in a lipid bilayer with an applied transmembrane potential, reveal single cation translocation events during transient periods of channel hydration. During the simulation trajectory, cations paused for prolonged periods near several rings of anionic residues projecting from the lumen of the extracellular domain of the receptor, but subsequently the cation moved rapidly through the hydrophobic transmembrane region as the constituent alpha-helices exhibited back and forth rocking motions. Cocrystallization of acetylcholine binding protein with sulfate ions revealed coordination of five sulfates with residues from one of these charged rings; in cation-selective Cys-loop receptors this ring contains negatively charged residues, whereas in anion-selective receptors it contains positively charged residues. In the muscle nicotinic receptor, charge reversal of residues of this ring decreases unitary conductance by up to 80%. Thus in Cys-loop receptors, a series of charged rings along the ion translocation pathway concentrates hydrated ions relative to bulk solution, giving rise to charge selectivity, and then subtle motions of the hydrophobic transmembrane, coupled with transient periods of water filling, enable rapid ion flux.

  20. 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.

  1. Association of GABA(B) receptors and members of the 14-3-3 family of signaling proteins.

    PubMed

    Couve, A; Kittler, J T; Uren, J M; Calver, A R; Pangalos, M N; Walsh, F S; Moss, S J

    2001-02-01

    Two GABA(B) receptors, GABA(B)R1 and GABA(B)R2, have been cloned recently. Unlike other G protein-coupled receptors, the formation of a heterodimer between GABA(B)R1 and GABA(B)R2 is required for functional expression. We have used the yeast two hybrid system to identify proteins that interact with the C-terminus of GABA(B)R1. We report a direct association between GABA(B) receptors and two members of the 14-3-3 protein family, 14-3-3eta and 14-3-3zeta. We demonstrate that the C-terminus of GABA(B)R1 associates with 14-3-3zeta in rat brain preparations and tissue cultured cells, that they codistribute after rat brain fractionation, colocalize in neurons, and that the binding site overlaps partially with the coiled-coil domain of GABA(B)R1. Furthermore we show a reduced interaction between the C-terminal domains of GABA(B)R1 and GABA(B)R2 in the presence of 14-3-3. The results strongly suggest that GABA(B)R1 and 14-3-3 associate in the nervous system and begin to reveal the signaling complexities of the GABA(B)R1/GABA(B)R2 receptor heterodimer.

  2. The PR5K receptor protein kinase from Arabidopsis thaliana is structurally related to a family of plant defense proteins.

    PubMed Central

    Wang, X; Zafian, P; Choudhary, M; Lawton, M

    1996-01-01

    We have isolated an Arabidopsis thaliana gene that codes for a receptor related to antifungal pathogenesis-related (PR) proteins. The PR5K gene codes for a predicted 665-amino acid polypeptide that comprises an extracellular domain related to the PR5 proteins, a central transmembrane-spanning domain, and an intracellular protein-serine/threonine kinase. The extracellular domain of PR5K (PR5-like receptor kinase) is most highly related to acidic PR5 proteins that accumulate in the extracellular spaces of plants challenged with pathogenic microorganisms. The kinase domain of PR5K is related to a family of protein-serine/threonine kinases that are involved in the expression of self-incompatibility and disease resistance. PR5K transcripts accumulate at low levels in all tissues examined, although particularly high levels are present in roots and inflorescence stems. Treatments that induce authentic PR5 proteins had no effect on the level of PR5K transcripts, suggesting that the receptor forms part of a preexisting surveillance system. When the kinase domain of PR5K was expressed in Escherichia coli, the resulting polypeptide underwent autophosphorylation, consistent with its predicted enzyme activity. These results are consistent with PR5K encoding a functional receptor kinase. Moreover, the structural similarity between the extracellular domain of PR5K and the antimicrobial PR5- proteins suggests a possible interaction with common or related microbial targets. Images Fig. 2 Fig. 3 Fig. 4 PMID:8637920

  3. 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.

  4. Fulvestrant regulates epidermal growth factor (EGF) family ligands to activate EGF receptor (EGFR) signaling in breast cancer cells.

    PubMed

    Zhang, Xihong; Diaz, Michael R; Yee, Douglas

    2013-06-01

    Estrogen receptor-α (ER) targeted therapies are routinely used to treat breast cancer. However, patient responses are limited by resistance to endocrine therapy. Breast cancer cells resistant to the pure steroidal ER antagonist fulvestrant (fulv) demonstrate increased activation of epidermal growth factor receptor (EGFR) family members and downstream ERK signaling. In this study, we investigated the effects of fulv on EGFR signaling and ligand regulation in several breast cancer cell lines. EGFR/HER2/HER3 phosphorylation and ERK1,2 activation were seen after 24-48 h after fulvestrant treatment in ER-positive breast cancer cell lines. 4-Hydroxy-tamoxifen and estradiol did not cause EGFR activation. Fulvestrant did not affect EGFR expression. Cycloheximide abolished the ability of fulv to activate EGFR suggesting the autocrine production of EGFR ligands might be responsible for fulvestrant induced EGFR signaling. qRT-PCR results showed fulv differentially regulated EGFR ligands; HB-EGF mRNA was increased, while amphiregulin and epiregulin mRNAs were decreased. Fulvestrant induced EGFR activation and upregulation of EGFR ligands were ER dependent since fulv treatment in C4-12, an ER-negative cell line derivative of MCF-7 cells, did not result in EGFR activation or change in ligand mRNA levels. ER downregulation by siRNA induced similar EGFR activation and regulation of EGFR ligands as fulvestrant. Neutralizing HB-EGF antibody blocked fulv-induced EGFR activation. Combination of fulv and EGFR family tyrosine kinase inhibitors (erlotinib and lapatinib) significantly decreased EGFR signaling and cell survival. In conclusion, fulvestrant-activated EGFR family members accompanied by ER dependent upregulation of HB-EGF within 48 h. EGF receptor or ligand inhibition might enhance or prolong the therapeutic effects of targeting ER by fulvestrant in breast cancer.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Family structure and phylogenetic analysis of odorant receptor genes in the large yellow croaker (Larimichthys crocea)

    PubMed Central

    2011-01-01

    Background Chemosensory receptors, which are all G-protein-coupled receptors (GPCRs), come in four types: odorant receptors (ORs), vomeronasal receptors, trace-amine associated receptors and formyl peptide receptor-like proteins. The ORs are the most important receptors for detecting a wide range of environmental chemicals in daily life. Most fish OR genes have been identified from genome databases following the completion of the genome sequencing projects of many fishes. However, it remains unclear whether these OR genes from the genome databases are actually expressed in the fish olfactory epithelium. Thus, it is necessary to clone the OR mRNAs directly from the olfactory epithelium and to examine their expression status. Results Eighty-nine full-length and 22 partial OR cDNA sequences were isolated from the olfactory epithelium of the large yellow croaker, Larimichthys crocea. Bayesian phylogenetic analysis classified the vertebrate OR genes into two types, with several clades within each type, and showed that the L. crocea OR genes of each type are more closely related to those of fugu, pufferfish and stickleback than they are to those of medaka, zebrafish and frog. The reconciled tree showed 178 duplications and 129 losses. The evolutionary relationships among OR genes in these fishes accords with their evolutionary history. The fish OR genes have experienced functional divergence, and the different clades of OR genes have evolved different functions. The result of real-time PCR shows that different clades of ORs have distinct expression levels. Conclusion We have shown about 100 OR genes to be expressed in the olfactory epithelial tissues of L. crocea. The OR genes of modern fishes duplicated from their common ancestor, and were expanded over evolutionary time. The OR genes of L. crocea are closely related to those of fugu, pufferfish and stickleback, which is consistent with its evolutionary position. The different expression levels of OR genes of large

  10. Complex Evolutionary Dynamics of Massively Expanded Chemosensory Receptor Families in an Extreme Generalist Chelicerate Herbivore

    PubMed Central

    Ngoc, Phuong Cao Thi; Greenhalgh, Robert; Dermauw, Wannes; Rombauts, Stephane; Bajda, Sabina; Zhurov, Vladimir; Grbić, Miodrag; Van de Peer, Yves; Van Leeuwen, Thomas; Rouzé, Pierre; Clark, Richard M.

    2016-01-01

    While mechanisms to detoxify plant produced, anti-herbivore compounds have been associated with plant host use by herbivores, less is known about the role of chemosensory perception in their life histories. This is especially true for generalists, including chelicerate herbivores that evolved herbivory independently from the more studied insect lineages. To shed light on chemosensory perception in a generalist herbivore, we characterized the chemosensory receptors (CRs) of the chelicerate two-spotted spider mite, Tetranychus urticae, an extreme generalist. Strikingly, T. urticae has more CRs than reported in any other arthropod to date. Including pseudogenes, 689 gustatory receptors were identified, as were 136 degenerin/Epithelial Na+ Channels (ENaCs) that have also been implicated as CRs in insects. The genomic distribution of T. urticae gustatory receptors indicates recurring bursts of lineage-specific proliferations, with the extent of receptor clusters reminiscent of those observed in the CR-rich genomes of vertebrates or C. elegans. Although pseudogenization of many gustatory receptors within clusters suggests relaxed selection, a subset of receptors is expressed. Consistent with functions as CRs, the genomic distribution and expression of ENaCs in lineage-specific T. urticae expansions mirrors that observed for gustatory receptors. The expansion of ENaCs in T. urticae to > 3-fold that reported in other animals was unexpected, raising the possibility that ENaCs in T. urticae have been co-opted to fulfill a major role performed by unrelated CRs in other animals. More broadly, our findings suggest an elaborate role for chemosensory perception in generalist herbivores that are of key ecological and agricultural importance. PMID:27797949

  11. 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

  12. 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

  13. ABA inhibits entry into stomatal-lineage development in Arabidopsis leaves.

    PubMed

    Tanaka, Yoko; Nose, Tomoe; Jikumaru, Yusuke; Kamiya, Yuji

    2013-05-01

    The number and density of stomata are controlled by endogenous and environmental factors. Despite recent advances in our understanding of stomatal development, mechanisms which prevent stomatal-lineage entry remain unclear. Here, we propose that abscisic acid (ABA), a phytohormone known to induce stomatal closure, limits initiation of stomatal development and induces enlargement of pavement cells in Arabidopsis cotyledons. An ABA-deficient aba2-2 mutant had an increased number/proportion of stomata within a smaller cotyledon, as well as reduced expansion of pavement cells. This tendency was reversed after ABA application or in an ABA over-accumulating cyp707a1cyp707a3 doublemutant. Our time course analysis revealed that aba2-2 shows prolonged formation of meristemoids and guard mother cells, both precursors of stoma. This finding is in accordance with prolonged gene expression of SPCH and MUTE, master regulators for stomatal formation, indicating that ABA acts upstream of these genes. Only aba2-2 mute, but not aba2-2 spch double mutant showed additive phenotypes and displayed inhibition of pavement cell enlargement with increased meristemoid number, indicating that ABA action on pavement cell expansion requires the presence of stomatal-lineage cells.

  14. 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

  15. [Accumulation of ABA and ODAP in Lathyrus sativus under water stress].

    PubMed

    Xing, G; Zhou, G; Li, Z; Cui, K

    2000-10-01

    The roots of fifteen days old Lathyrus sativus seedlings were treated by PEG, PEG + ABA and ABA, and their leaves were sampled to determine the contents of endogenic ABA, ODAP, MDA and H2O2 and the activity of superoxide dismutase, catalase, peroxidase and glutathione reductase. The results showed that after treated, the contents of ABA and ODAP in leaves increased markedly. The addition of exogenous ABA decreased the increment of MDA and H2O2 contents and retarded the attenuation of CAT activity, which were induced by PEG stress, and enhanced the GR activity. In addition, when materials were treated with exogenous ABA in a long time, the ABA content in leaves was increased markedly, and ODAP was then accumulated. There was no significant effect on metabolism of active oxygen in the early days(0-3 days) of ABA treatment, but the activities of SOD, POD, CAT and GR decreased, and the contents of MDA and H2O2 increased in leaves of Lathyrus sativus with the duration of ABA treatment(7-15 days). The results indicated that ABA could promote the accumulation of ODAP in leaves of Lathyrus sativus.

  16. Comprehensive Analysis of ABA Effects on Ethylene Biosynthesis and Signaling during Tomato Fruit Ripening.

    PubMed

    Mou, Wangshu; Li, Dongdong; 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.

  17. 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

  18. 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.

  19. 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

  20. Nuclear Receptor 4A (NR4A) Family – Orphans No More

    PubMed Central

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

    2015-01-01

    The orphan nuclear receptors NR4A1, NR4A2 and NR4A3 are immediate early genes induced by multiple stressors, and the NR4A1 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. PMID:25917081

  1. Frequent overexpression of ErbB--receptor family members in brain metastases of non-small cell lung cancer patients.

    PubMed

    Berghoff, Anna Sophie; Magerle, Manuel; Ilhan-Mutlu, Ayseguel; Dinhof, Carina; Widhalm, Georg; Dieckman, Karin; Marosi, Christine; Wöhrer, Adelheid; Hackl, Monika; Zöchbauer-Müller, Sabine; Preusser, Matthias; Birner, Peter

    2013-12-01

    The ErbB receptor family has been implicated in brain metastases (BM) formation in various cancer types and specific targeted therapies are available. We investigated the overexpression of EGFR, HER2 and HER3 in BM of non-small cell lung cancer (NSCLC) patients to get a better insight on pathobiology of BM and potential drugable targets. We performed immunohistochemical analysis of EGFR, HER2 and HER3 on tissue microarrays of 131 NSCLC-BM. Fifty-one of 131 (38.9%) specimens were considered as positive for EGFR overexpression, 12/131 (9.2%) for HER2 and 27/131 (20.6%) for HER3 respectively. Sixty-nine of 131 (52.7%) of the cases showed overexpression of at least one marker. Four of 131 (3.1%) were positive for all three markers. Strong correlation was observed between HER2 and HER3 overexpression (p = 0.009; Chi-square test after Bonferroni-Holmes correction). No statistically significant correlation of EGFR, HER2 or HER3 overexpression with clinico-pathological parameters including overall survival times was observed. We observed overexpression of ErbB receptor family members, which represent established therapeutic targets in various primary tumours, in approximately half of NSCLC-BM. Further studies should investigate the role of the ErbB pathway in development of and as a therapeutic target in BM of NSCLC patients.

  2. The epidermal growth factor receptor/Erb-B/HER family in normal and malignant breast biology.

    PubMed

    Eccles, Suzanne A

    2011-01-01

    The EGFR/Erb-B receptor tyrosine kinases each play distinct and complementary roles in normal breast development. The four receptors form both homodimers and heterodimers in response to binding by ligands which show selectivity for one or more of the receptors (except Erb-B2). Together with the additional flexibility generated by the formation of different dimer pairs, these signalling networks play key roles in directing a variety of both autocrine and paracrine cellular responses. Complex two-way interactions between mammary epithelial cells and the surrounding stroma direct proliferation, duct formation, branching and terminal differentiation during puberty, pregnancy and lactation, with each receptor and ligand fulfilling distinct roles. Caricatures of the normal role of EGFR/Erb-B signalling resulting in aberrant cellular responses are seen in breast cancers, where over-expression and/or (less commonly) mutation of one or more of the receptors results in enhanced cell proliferation, motility, release of proteases and angiogenic factors. Given their importance in tumour progression, compared with most normal adult tissues and their links with resistance to chemotherapy and anti-endocrine therapy, Erb-B receptors (most notably Erb-B2) have been exploited as therapeutic targets. Monoclonal antibodies (e.g. trastuzumab, pertuzumab) and small molecule tyrosine kinase inhibitors (e.g. lapatinib, afatinib) have shown significant clinical responses in some breast cancer subtypes. Additional approaches include targeted toxins or drugs, peptide vaccines, immunRNase and chaperone inhibitors to deplete Erb-B2 protein levels. Greater understanding of the full spectrum of Erb-B-mediated signalling pathways and their misregulation in breast cancer will provide additional strategies to control malignant progression.

  3. 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.

  4. 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

  5. Depletion of abscisic acid levels in roots of flooded Carrizo citrange (Poncirus trifoliata L. Raf. × Citrus sinensis L. Osb.) plants is a stress-specific response associated to the differential expression of PYR/PYL/RCAR receptors.

    PubMed

    Arbona, Vicent; Zandalinas, Sara I; Manzi, Matías; González-Guzmán, Miguel; Rodriguez, Pedro L; Gómez-Cadenas, Aurelio

    2017-04-01

    Soil flooding reduces root abscisic acid (ABA) levels in citrus, conversely to what happens under drought. Despite this reduction, microarray analyses suggested the existence of a residual ABA signaling in roots of flooded Carrizo citrange seedlings. The comparison of ABA metabolism and signaling in roots of flooded and water stressed plants of Carrizo citrange revealed that the hormone depletion was linked to the upregulation of CsAOG, involved in ABA glycosyl ester (ABAGE) synthesis, and to a moderate induction of catabolism (CsCYP707A, an ABA 8'-hydroxylase) and buildup of dehydrophaseic acid (DPA). Drought strongly induced both ABA biosynthesis and catabolism (CsNCED1, 9-cis-neoxanthin epoxycarotenoid dioxygenase 1, and CsCYP707A) rendering a significant hormone accumulation. In roots of flooded plants, restoration of control ABA levels after stress release was associated to the upregulation of CsBGLU18 (an ABA β-glycosidase) that cleaves ABAGE. Transcriptional profile of ABA receptor genes revealed a different induction in response to soil flooding (CsPYL5) or drought (CsPYL8). These two receptor genes along with CsPYL1 were cloned and expressed in a heterologous system. Recombinant CsPYL5 inhibited ΔNHAB1 activity in vitro at lower ABA concentrations than CsPYL8 or CsPYL1, suggesting its better performance under soil flooding conditions. Both stress conditions induced ABA-responsive genes CsABI5 and CsDREB2A similarly, suggesting the occurrence of ABA signaling in roots of flooded citrus seedlings. The impact of reduced ABA levels in flooded roots on CsPYL5 expression along with its higher hormone affinity reinforce the role of this ABA receptor under soil-flooding conditions and explain the expression of certain ABA-responsive genes.

  6. Familial ligand-defective apolipoprotein B. Identification of a new mutation that decreases LDL receptor binding affinity.

    PubMed Central

    Pullinger, C R; Hennessy, L K; Chatterton, J E; Liu, W; Love, J A; Mendel, C M; Frost, P H; Malloy, M J; Schumaker, V N; Kane, J P

    1995-01-01

    Detection of new ligand-defective mutations of apolipoprotein B (apoB) will enable identification of sequences involved in binding to the LDL receptor. Genomic DNA from patients attending a lipid clinic was screened by single-strand conformation polymorphism analysis for novel mutations in the putative LDL receptor-binding domain of apoB-100. A 46-yr-old woman of Celtic and Native American ancestry with primary hypercholesterolemia (total cholesterol [TC] 343 mg/dl; LDL cholesterol [LDL-C] 241 mg/dl) and pronounced peripheral vascular disease was found to be heterozygous for a novel Arg3531-->Cys mutation, caused by a C-->T transition at nucleotide 10800. One unrelated 59-yr-old man of Italian ancestry was found with the same mutation after screening 1,560 individuals. He had coronary heart disease, a TC of 310 mg/dl, and an LDL-C of 212 mg/dl. A total of eight individuals were found with the defect in the families of the two patients. They had an age- and sex-adjusted TC of 240 +/- 14 mg/dl and LDL-C of 169 +/- 10 mg/dl. This compares with eight unaffected family members with age- and sex-adjusted TC of 185 +/- 12 mg/dl and LDL-C of 124 +/- 12 mg/dl. In a dual-label fibroblast binding assay, LDL from the eight subjects with the mutation had an affinity for the LDL receptor that was 63% that of control LDL. LDL from eight unaffected family members had an affinity of 91%. By way of comparison, LDL from six patients heterozygous for the Arg3500-->Gln mutation had an affinity of 36%. The percentage mass ratio of the defective Cys3531 LDL to normal LDL was 59:41, as determined using the mAb MB19 and dynamic laser light scattering. Thus, the defective LDL had accumulated in the plasma of these patients. Using this mass ratio, it was calculated that the defective Cys3531 LDL particles bound with 27% of normal affinity. Deduced haplotypes using 10 apoB gene markers showed the Arg3531-->Cys alleles to be different in the two kindreds and indicates that the mutations arose

  7. The Medicago truncatula lysin [corrected] motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes.

    PubMed

    Arrighi, Jean-François; Barre, Annick; Ben Amor, Besma; Bersoult, Anne; Soriano, Lidia Campos; Mirabella, Rossana; de Carvalho-Niebel, Fernanda; Journet, Etienne-Pascal; Ghérardi, Michèle; Huguet, Thierry; Geurts, René; Dénarié, Jean; Rougé, Pierre; Gough, Clare

    2006-09-01

    Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide further evidence for this by showing that NFP is a lysin [corrected] motif (LysM)-receptor-like kinase (RLK). NFP was shown both to be expressed in association with infection thread development and to be involved in the infection process. Consistent with deviations from conserved kinase domain sequences, NFP did not show autophosphorylation activity, suggesting that NFP needs to associate with an active kinase or has unusual functional characteristics different from classical kinases. Identification of nine new M. truncatula LysM-RLK genes revealed a larger family than in the nonlegumes Arabidopsis (Arabidopsis thaliana) or rice (Oryza sativa) of at least 17 members that can be divided into three subfamilies. Three LysM domains could be structurally predicted for all M. truncatula LysM-RLK proteins, whereas one subfamily, which includes NFP, was characterized by deviations from conserved kinase sequences. Most of the newly identified genes were found to be expressed in roots and nodules, suggesting this class of receptors may be more extensively involved in nodulation than was previously known.

  8. Androgen Receptor Activation in Castration-Recurrent Prostate Cancer: The Role of Src-Family and Ack1 Tyrosine Kinases

    PubMed Central

    Gelman, Irwin H.

    2014-01-01

    There is growing appreciation that castration-recurrent prostate cancer (CR-CaP) is driven by the continued expression of androgen receptor (AR). AR activation in CR-CaP through various mechanisms, including AR overexpression, expression of AR splice variants or mutants, increased expression of co-regulator proteins, and by post-translational modification, allows for the induction of AR-regulated genes in response to very low levels of tissue-expressed, so-called intracrine androgens, resulting in pathways that mediate CaP proliferation, anti-apoptosis and oncogenic aggressiveness. The current review focuses on the role played by Src-family (SFK) and Ack1 non-receptor tyrosine kinases in activating AR through direct phosphorylation, respectively, on tyrosines 534 or 267, and how these modifications facilitate progression to CR-CaP. The fact that SFK and Ack1 are central mediators for multiple growth factor receptor signaling pathways that become activated in CR-CaP, especially in the context of metastatic growth in the bone, has contributed to recent therapeutic trials using SFK/Ack1 inhibitors in monotherapy or in combination with antagonists of the AR activation axis. PMID:24948875

  9. The Tetraspanin-Associated Uroplakins Family (UPK2/3) Is Evolutionarily Related to PTPRQ, a Phosphotyrosine Phosphatase Receptor

    PubMed Central

    Chicote, Javier U.; DeSalle, Rob; Segarra, José; Sun, Tung-Tien; García-España, Antonio

    2017-01-01

    Uroplakins are a widespread group of vertebrate integral membrane proteins that belong to two different families: UPK1a and UPK1b belong to the large tetraspanin (TSPAN) gene family, and UPK3a, UPK3b, UPK3c, UPK3d, UPK2a and UPK2b form a family of their own, the UPK2/3 tetraspanin-associated family. In a previous study, we reported that uroplakins first appeared in vertebrates, and that uroplakin tetraspanins (UPK1a and UPK1b) should have originated by duplication of an ancestor tetraspanin gene. However, the evolutionary origin of the UPK2/3 family remains unclear. In this study, we provide evidence that the UPK2/3 family originated by gene duplication and domain loss from a protoPTPRQ-like basal deuterostome gene. PTPRQs are members of the subtype R3 tyrosine phosphatase receptor (R3 PTPR) family, which are characterized by having a unique modular composition of extracellular fibronectin (FN3) repeats, a transmembrane helix, and a single intra-cytoplasmic phosphotyrosine phophatase (PTP) domain. Our assumption of a deuterostome protoPTPRQ-like gene as an ancestor of the UPK2/3 family by gene duplication and loss of its PTP and fibronectin (FN3) domains, excluding the one closest to the transmembrane helix, is based on the following: (i) phylogenetic analyses, (ii) the existence of an identical intron/exon gene pattern between UPK2/3 and the corresponding genetic region in R3 PTPRs, (iii) the conservation of cysteine patterns and protein motifs between UPK2/3 and PTPRQ proteins and, (iv) the existence in tunicates, the closest organisms to vertebrates, of two sequences related to PTPRQ; one with the full subtype R3 modular characteristic and another without the PTP domain but with a short cytoplasmic tail with some sequence similarity to that of UPK3a. This finding will facilitate further studies on the structure and function of these important proteins with implications in human diseases. PMID:28099513

  10. Signaling cross-talk in the resistance to HER family receptor targeted therapy.

    PubMed

    Yamaguchi, H; Chang, S-S; Hsu, J L; Hung, M-C

    2014-02-27

    Epidermal growth factor receptor (EGFR) and human EGFR 2 (HER2) have an important role in the initiation and progression of various types of cancer. Inhibitors targeting these receptor tyrosine kinases are some of the most successful targeted anticancer drugs widely used for cancer treatment; however, cancer cells have mechanisms of intrinsic and acquired drug resistance that pose as major obstacles in drug efficacy. Extensive studies from both clinical and laboratory research have identified several molecular mechanisms underlying resistance. Among them is the role of signaling cross-talk between the EGFR/HER2 and other signaling pathways. In this review, we focus particularly on this signaling cross-talk at the receptor, mediator and effector levels, and further discuss alternative approaches to overcome resistance. In addition to well-recognized signaling cross-talk involved in the resistance, we also introduce the cross-talk between EGFR/HER2-mediated pathways and pathways triggered by other types of receptors, including those of the Notch, Wnt and TNFR/IKK/NF-κB pathways, and discuss the potential role of targeting this cross-talk to sensitize cells to EGFR/HER2 inhibitors.

  11. Mapping of the toll like receptor family in channel catfish, Ictalurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Toll Like Receptors (TLRs) are key elements of the innate response to pathogens. They recognize Pathogen Associated Molecular Patterns (PAMPs) and activate the host defense responses. As such, they are candidate genes for disease resistance. In teleost, eight homologs of the endothermic vertebra...

  12. FoxG1, a member of the forkhead family, is a corepressor of the androgen receptor.

    PubMed

    Obendorf, Maik; Meyer, Rene; Henning, Konstanze; Mitev, Youri A; Schröder, Jens; Patchev, Vladimir K; Wolf, Siegmund S

    2007-05-01

    The androgen receptor (AR) is a ligand-dependent transcriptional regulator which belongs to the nuclear receptor superfamily. The basal transcriptional activity of the androgen receptor is regulated by interaction with coactivator or corepressor proteins. The exact mechanism whereby comodulators influence target gene transcription is only partially understood, especially for corepressors. Whereas several coactivators are described for the AR, only a few corepressors are known. Here, we describe the discovery of a new androgen receptor corepressor, FoxG1, which belongs to the forkhead family. By using a fragment of the AR (aa 325-919) as bait in a yeast two hybrid screen, the C-terminal region (aa 175-489) of FoxG1 (also known as BF1), was identified as AR-interacting protein. Binding of AR to the FoxG1 fragment was verified by one- and two-hybrid assays, and pull-down experiments. In addition, we show that the full-length form of FoxG1 functions as a strong corepressor in the AR-mediated transactivation. The FoxG1 expression profile in adult individuals is restricted to brain and testis in human and decreases during aging in the rodent brain. Both AR and FoxG1 expression are developmentally regulated. Besides its reported role in neurogenesis, the strong expression of FoxG1 in AR-abundant areas of the adult brain suggests possible involvement in neuroendocrine regulation. Taken together, the data presented suggest that, in addition to repression of transcription by direct binding to DNA, FoxG1 may interact with AR in vivo, thereby targeting its repressor function specifically to sex hormone signaling.

  13. Analysis of Somatic Mutations in Cancer: Molecular Mechanisms of Activation in the ErbB Family of Receptor Tyrosine Kinases

    PubMed Central

    Shih, Andrew J.; Telesco, Shannon E.; Radhakrishnan, Ravi

    2011-01-01

    The ErbB/EGFR/HER family of kinases consists of four homologous receptor tyrosine kinases which are important regulatory elements in many cellular processes, including cell proliferation, differentiation, and migration. Somatic mutations in, or over-expression of, the ErbB family is found in many cancers and is correlated with a poor prognosis; particularly, clinically identified mutations found in non-small-cell lung cancer (NSCLC) of ErbB1 have been shown to increase its basal kinase activity and patients carrying these mutations respond remarkably to the small tyrosine kinase inhibitor gefitinib. Here, we analyze the potential effects of the currently catalogued clinically identified mutations in the ErbB family kinase domains on the molecular mechanisms of kinase activation. Recently, we identified conserved networks of hydrophilic and hydrophobic interactions characteristic to the active and inactive conformation, respectively. Here, we show that the clinically identified mutants influence the kinase activity in distinctive fashion by affecting the characteristic interaction networks. PMID:21701703

  14. Duplex High Throughput Flow Cytometry Screen Identifies Two Novel Formylpeptide Receptor Family Probes1

    PubMed Central

    Young, Susan M.; Bologa, Cristian M.; Fara, Dan; Bryant, Bj K.; Strouse, J. Jacob; Arterburn, Jeffrey B.; Ye, Richard D.; Oprea, Tudor I.; Prossnitz, Eric R.; Sklar, Larry A.; Edwards, Bruce S.

    2008-01-01

    Introduction Of recent clinical interest have been two related human G-protein coupled receptors: formylpeptide receptor (FPR), linked to anti-bacterial inflammation and malignant glioma cell metastasis; and formylpeptide receptor like-1 (FPRL1), linked to chronic inflammation in systemic amyloidosis, Alzheimer’s disease and prion diseases. In association with the National Institutes of Health (NIH) Molecular Library Screening Network, we implemented a flow cytometry based high throughput screening (HTS) approach for identifying selective small molecule FPR and FPRL1 ligands. Methods The screening assay measured the ability of test compounds to competitively displace a high-affinity, fluorescein-labeled peptide ligand from FPR, FPRL1 or both. U937 cells expressing FPR and RBL cells expressing FPRL1 were tested together in a “duplex” format. The U937 cells were color-coded with red fluorescent dye allowing their distinction during analysis. Compounds, cells and fluorescent ligand were sequentially combined (no-wash) in 15 μL assay volumes in 384-well plates. Throughput averaged ∼11 min per plate to analyze ∼4000 cells (∼2000/receptor) in a 2 μL aspirate from each well. Results/Conclusions In primary single concentration HTS of 24,304 NIH Small Molecule Repository compounds, 253 resulted in inhibition >30% (181 for FPR, 72 for FPRL1) of which 40 had selective binding inhibition constants (Ki) ≤ 4 μM (34 for FPR and 6 for FPRL1). An additional 1,446 candidate compounds were selected by structure-activity -relationship analysis of the hits and screened to identify novel ligands for FPR (3570-0208, Ki= 95 ± 10 nM) and FPRL1 (BB-V-115, Ki= 270 ± 51 nM). Each was a selective antagonist in calcium response assays and the most potent small molecule antagonist reported for its respective receptor to date. The duplex assay format reduced assay time, minimized reagent requirements, and provided selectivity information at every screening stage, thus proving

  15. 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

  16. Activation and crosstalk between TNF family receptors in umbilical cord blood cells is not responsible for loss of engraftment capacity following culture

    PubMed Central

    Mizrahi, Keren; Askenasy, Nadir

    2013-01-01

    Umbilical cord blood (UCB) is a rich source of hematopoietic progenitors for transplantation. Murine and human progenitors are insensitive to apoptotic signaling mediated by the TNF family receptors, however extension of culture over 48 hours is accompanied by severe deterioration in engraftment and hematopoietic reconstituting capacity. In this study we assessed crosstalk between the Fas, TNF and TRAIL receptors, and questioned whether it contributes to increased mortality and decreased activity of UCB progenitors following extended ex vivo culture for 72 hours. The well-characterized TNF-induced expression of Fas is mediated by both TNF receptors, yet the TNF receptors determine survival rather than Fas: superior viability of TNF-R1 progenitors. Additional cross talk includes upregulation of TRAIL-R1 by Fas-ligand, mediated both by fast cycling and inductive crosstalk. These inductive interactions are not accompanied by concomitant sensitization of progenitors to receptor-mediated apoptosis during extended culture, but rather decreased fractional apoptosis in expanded progenitor subsets expressing the receptors. TRAIL upregulates both TRAIL-R1 and TRAIL-R2, accompanied by commensurate susceptibility to spontaneous apoptosis. The current data reveal inductive crosstalk between TNF family receptors, which are largely dissociated from the sensitivity of hematopoietic progenitors to apoptosis. Activation of Fas, TNF and TRAIL receptors and excessive apoptosis are not responsible for loss of engraftment and impaired reconstituting activity of UCB progenitors following extended culture. PMID:24396708

  17. Activation and crosstalk between TNF family receptors in umbilical cord blood cells is not responsible for loss of engraftment capacity following culture.

    PubMed

    Mizrahi, Keren; Askenasy, Nadir

    2013-01-01

    Umbilical cord blood (UCB) is a rich source of hematopoietic progenitors for transplantation. Murine and human progenitors are insensitive to apoptotic signaling mediated by the TNF family receptors, however extension of culture over 48 hours is accompanied by severe deterioration in engraftment and hematopoietic reconstituting capacity. In this study we assessed crosstalk between the Fas, TNF and TRAIL receptors, and questioned whether it contributes to increased mortality and decreased activity of UCB progenitors following extended ex vivo culture for 72 hours. The well-characterized TNF-induced expression of Fas is mediated by both TNF receptors, yet the TNF receptors determine survival rather than Fas: superior viability of TNF-R1 progenitors. Additional cross talk includes upregulation of TRAIL-R1 by Fas-ligand, mediated both by fast cycling and inductive crosstalk. These inductive interactions are not accompanied by concomitant sensitization of progenitors to receptor-mediated apoptosis during extended culture, but rather decreased fractional apoptosis in expanded progenitor subsets expressing the receptors. TRAIL upregulates both TRAIL-R1 and TRAIL-R2, accompanied by commensurate susceptibility to spontaneous apoptosis. The current data reveal inductive crosstalk between TNF family receptors, which are largely dissociated from the sensitivity of hematopoietic progenitors to apoptosis. Activation of Fas, TNF and TRAIL receptors and excessive apoptosis are not responsible for loss of engraftment and impaired reconstituting activity of UCB progenitors following extended culture.

  18. Expression Analysis of Four Peroxiredoxin Genes from Tamarix hispida in Response to Different Abiotic Stresses and Exogenous Abscisic Acid (ABA)

    PubMed Central

    Gao, Caiqiu; Zhang, Kaimin; Yang, Guiyan; Wang, Yucheng

    2012-01-01

    Peroxiredoxins (Prxs) are a recently discovered family of antioxidant enzymes that catalyze the reduction of peroxides and alkyl peroxides. In this study, four Prx genes (named as ThPrxII, ThPrxIIE, ThPrxIIF, and Th2CysPrx) were cloned from Tamarix hispida. Their expression profiles in response to stimulus of NaCl, NaHCO3, PEG, CdCl2 and abscisic acid (ABA) in roots, stems and leaves of T. hispida were investigated using real-time RT-PCR. The results showed that the four ThPrxs were all expressed in roots, stems and leaves. Furthermore, the transcript levels of ThPrxIIE and ThPrxII were the lowest and the highest, respectively, in all tissue types. All the ThPrx genes were induced by both NaCl and NaHCO3 and reached their highest expression levels at the onset of stress in roots. Under PEG and CdCl2 stress, the expression patterns of these ThPrxs showed temporal and spatial specificity. The expressions of the ThPrxs were all differentially regulated by ABA, indicating that they are all involved in the ABA signaling pathway. These findings reveal a complex regulation of Prxs that is dependent on the type of Prx, tissue, and the signaling molecule. The divergence of the stress-dependent transcriptional regulation of the ThPrx gene family in T. hispida may provide an essential basis for the elucidation of Prx function in future work. PMID:22489180

  19. Expression analysis of four peroxiredoxin genes from Tamarix hispida in response to different abiotic stresses and Exogenous Abscisic Acid (ABA).

    PubMed

    Gao, Caiqiu; Zhang, Kaimin; Yang, Guiyan; Wang, Yucheng

    2012-01-01

    Peroxiredoxins (Prxs) are a recently discovered family of antioxidant enzymes that catalyze the reduction of peroxides and alkyl peroxides. In this study, four Prx genes (named as ThPrxII, ThPrxIIE, ThPrxIIF, and Th2CysPrx) were cloned from Tamarix hispida. Their expression profiles in response to stimulus of NaCl, NaHCO(3), PEG, CdCl(2) and abscisic acid (ABA) in roots, stems and leaves of T. hispida were investigated using real-time RT-PCR. The results showed that the four ThPrxs were all expressed in roots, stems and leaves. Furthermore, the transcript levels of ThPrxIIE and ThPrxII were the lowest and the highest, respectively, in all tissue types. All the ThPrx genes were induced by both NaCl and NaHCO(3) and reached their highest expression levels at the onset of stress in roots. Under PEG and CdCl(2) stress, the expression patterns of these ThPrxs showed temporal and spatial specificity. The expressions of the ThPrxs were all differentially regulated by ABA, indicating that they are all involved in the ABA signaling pathway. These findings reveal a complex regulation of Prxs that is dependent on the type of Prx, tissue, and the signaling molecule. The divergence of the stress-dependent transcriptional regulation of the ThPrx gene family in T. hispida may provide an essential basis for the elucidation of Prx function in future work.

  20. 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.

  1. 77 FR 36231 - Americans With Disabilities Act (ADA) and Architectural Barriers Act (ABA) Accessibility...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ... standards for residential facilities are the Uniform Federal Accessibility Standards (UFAS). When HUD... residential facilities covered by the ABA are the Uniform Federal Accessibility Standards (UFAS).\\5\\ HUD...

  2. 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

  3. 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.

  4. Characterization of a family of gamma-ray-induced CHO mutants demonstrates that the ldlA locus is diploid and encodes the low-density lipoprotein receptor

    SciTech Connect

    Sege, R.D.; Kozarsky, K.F.; Krieger, M.

    1986-09-01

    The ldlA locus is one of four Chinese hamster ovary (CHO) cell loci which are known to be required for the synthesis of functional low-density lipoprotein (LDL) receptors. Previous studies have suggested that the ldlA locus is diploid and encodes the LDL receptor. To confirm this assignment, we have isolated a partial genomic clone of the Chinese hamster LDL receptor gene and used this and other nucleic acid and antibody probes to study a family of ldlA mutants isolated after gamma-irradiation. Our analysis suggests that there are two LDL receptor alleles in wild-type CHO cells. Each of the three mutants isolated after gamma-irradiation had detectable deletions affecting one of the two LDL receptor alleles. One of the mutants also had a disruption of the remaining allele, resulting in the synthesis of an abnormal receptor precursor which was not subject to Golgi-associated posttranslational glycoprotein processing. The correlation of changes in the expression, structure, and function of LDL receptors with deletions in the LDL receptor genes in these mutants directly demonstrated that the ldlA locus in CHO cells is diploid and encodes the LDL receptor. In addition, our analysis suggests that CHO cells in culture may contain a partial LDL receptor pseudogene.

  5. Characterization of a family of gamma-ray-induced CHO mutants demonstrates that the ldlA locus is diploid and encodes the low-density lipoprotein receptor.

    PubMed

    Sege, R D; Kozarsky, K F; Krieger, M

    1986-09-01

    The ldlA locus is one of four Chinese hamster ovary (CHO) cell loci which are known to be required for the synthesis of functional low-density lipoprotein (LDL) receptors. Previous studies have suggested that the ldlA locus is diploid and encodes the LDL receptor. To confirm this assignment, we have isolated a partial genomic clone of the Chinese hamster LDL receptor gene and used this and other nucleic acid and antibody probes to study a family of ldlA mutants isolated after gamma-irradiation. Our analysis suggests that there are two LDL receptor alleles in wild-type CHO cells. Each of the three mutants isolated after gamma-irradiation had detectable deletions affecting one of the two LDL receptor alleles. One of the mutants also had a disruption of the remaining allele, resulting in the synthesis of an abnormal receptor precursor which was not subject to Golgi-associated posttranslational glycoprotein processing. The correlation of changes in the expression, structure, and function of LDL receptors with deletions in the LDL receptor genes in these mutants directly demonstrated that the ldlA locus in CHO cells is diploid and encodes the LDL receptor. In addition, our analysis suggests that CHO cells in culture may contain a partial LDL receptor pseudogene.

  6. Familial hypercalcemia and hypercalciuria: no mutations in the Ca2+-sensing receptor gene.

    PubMed

    Rodríguez-Soriano, J; Vallo, A; Quintela, M J; Pérez de Nanclares, G; Bilbao, J R; Castaño, L

    2001-09-01

    A 6-year-old boy presented with persistent hypercalcemia, hypercalciuria and nephrocalcinosis from early infancy. His 40-year-old father also had hypercalcemia and hypercalciuria. In both individuals serum values of intact parathyroid hormone (PTH) were repeatedly normal. Although these findings suggest a functional abnormality of the calcium-sensing receptor (CaR), no mutations in coding regions of the CaR gene could be demonstrated.

  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. Jasmonic acid accumulation and systemic photosynthetic and electrical changes in locally burned wild type tomato, ABA-deficient sitiens mutants and sitiens pre-treated by ABA.

    PubMed

    Hlavinka, Jan; Nožková-Hlaváčková, Vladimíra; Floková, Kristýna; Novák, Ondřej; Nauš, Jan

    2012-05-01

    Burning the terminal leaflet of younger tomato (Lycopersicon esculentum Mill.) leaf caused local and systemic changes in the surface electrical potential (SEP) and gas exchange (GE) parameters. The local and systemic accumulation of endogenous abscisic acid (ABA) and jasmonic acid (JA) was measured 85 min after burning. The experiments were conducted with wild type (WT) plants, ABA-deficient mutant sitiens (SIT) and ABA pre-treated SIT plants (SITA). First changes in SEP were detected within 1.5 min after burning and were followed by a decrease in GE parameters within 3-6 min in WT, SIT and SITA plants. GE and SEP time courses of SIT were different and wave amplitudes of SEP of SIT were lower compared to WT and SITA. ABA content in WT and SITA control plants was similar and substantially higher compared to SIT, JA content was similar among WT, SIT and SITA. While changes in the ABA content in systemic leaves have not been recorded after burning, the systemic JA content was substantially increased in WT and more in SIT and SITA. The results suggest that ABA content governs the systemic reaction of GE and the SEP shape upon local burning. ABA, JA and SEP participate in triggering the GE reaction. The ABA shortage in the SIT in the reaction to burning is partly compensated by an enhanced JA accumulation. This JA compensation is maintained even in SIT endogenously supplied with ABA. A correlation between the systemic JA content and changes in GE parameters or SEP was not found.

  9. Plant responses to drought stress and exogenous ABA application are modulated differently by mycorrhization in tomato and an ABA-deficient mutant (sitiens).

    PubMed

    Aroca, Ricardo; Del Mar Alguacil, Maria; Vernieri, Paolo; Ruiz-Lozano, Juan Manuel

    2008-11-01

    The aims of the present study are to find out whether the effects of arbuscular mycorrhizal (AM) symbiosis on plant resistance to water deficit are mediated by the endogenous abscisic acid (ABA) content of the host plant and whether the exogenous ABA application modifies such effects. The ABA-deficient tomato mutant sitiens and its near-isogenic wild-type parental line were used. Plant development, physiology, and expression of plant genes expected to be modulated by AM symbiosis, drought, and ABA were studied. Results showed that only wild-type tomato plants responded positively to mycorrhizal inoculation, while AM symbiosis was not observed to have any effect on plant development in sitiens plants grown under well-watered conditions. The application of ABA to sitiens plants enhanced plant growth both under well-watered and drought stress conditions. In respect to sitiens plants subjected to drought stress, the addition of ABA had a cumulative effect in relation to that of inoculation with G. intraradices. Most of the genes analyzed in this study showed different regulation patterns in wild-type and sitiens plants, suggesting that their gene expression is modulated by the plant ABA phenotype. In the same way, the colonization of roots with the AM fungus G. intraradices differently regulated the expression of these genes in wild-type and in sitiens plants, which could explain the distinctive effect of the symbiosis on each plant ABA phenotype. This also suggests that the effects of the AM symbiosis on plant responses and resistance to water deficit are mediated by the plant ABA phenotype.

  10. 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

  11. 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.

  12. Duplex high-throughput flow cytometry screen identifies two novel formylpeptide receptor family probes.

    PubMed

    Young, Susan M; Bologa, Cristian M; Fara, Dan; Bryant, Bj K; Strouse, Juan Jacob; Arterburn, Jeffrey B; Ye, Richard D; Oprea, Tudor I; Prossnitz, Eric R; Sklar, Larry A; Edwards, Bruce S

    2009-03-01

    Of recent, clinical interest have been two related human G-protein coupled receptors: formylpeptide receptor (FPR), linked to antibacterial inflammation and malignant glioma cell metastasis; and FPR like-1 (FPRL1), linked to chronic inflammation in systemic amyloidosis, Alzheimer's disease, and prion diseases. In association with the National Institutes of Health (NIH) Molecular Library Screening Network, we implemented a flow-cytometry-based high-throughput screening (HTS) approach for identifying selective small molecule FPR and FPRL1 ligands. The screening assay measured the ability of test compounds to competitively displace a high-affinity, fluorescein- labeled peptide ligand from FPR, FPRL1, or both. U937 cells expressing FPR and rat basophil leukemia (RBL) cells expressing FPRL1 were tested together in a "duplex" format. The U937 cells were color coded with red-fluorescent dye allowing their distinction during analysis. Compounds, cells, and fluorescent ligand were sequentially combined (no wash) in 15 microl assay volumes in 384-well plates. Throughput averaged approximately 11 min per plate to analyze approximately 4,000 cells ( approximately 2,000/receptor) in a 2 microl aspirate from each well. In primary single concentration HTS of 24,304 NIH Small Molecule Repository compounds, 253 resulted in inhibition >30% (181 for FPR, 72 for FPRL1) of which 40 had selective binding inhibition constants (K(i)) < or = 4 microM (34 for FPR and 6 for FPRL1). An additional 1,446 candidate compounds were selected by structure-activity-relationship analysis of the hits and screened to identify novel ligands for FPR (3570-0208, K(i) = 95 +/- 10 nM) and FPRL1 (BB-V-115, K(i) = 270 +/- 51 nM). Each was a selective antagonist in calcium response assays and the most potent small molecule antagonist reported for its respective receptor to date. The duplex assay format reduced assay time, minimized reagent requirements, and provided selectivity information at every screening

  13. Arabidopsis ERECTA-family receptor kinases mediate morphological alterations stimulated by activation of NB-LRR-type UNI proteins.

    PubMed

    Uchida, Naoyuki; Igari, Kadunari; Bogenschutz, Naomi L; Torii, Keiko U; Tasaka, Masao

    2011-05-01

    Shoot apical meristems (SAMs), which maintain stem cells at the tips of stems, and axillary meristems (AMs), which arise at leaf axils for branch formation, play significant roles in the establishment of plant architecture. Previously, we showed that, in Arabidopsis thaliana, activation of NB-LRR (nucleotide-binding site-leucine-rich repeat)-type UNI proteins affects plant morphology through modulation of the regulation of meristems. However, information about genes involved in the processes was still lacking. Here, we report that ERECTA (ER) receptor kinase family members cooperatively mediate the morphological alterations that are stimulated by activation of UNI proteins. uni-1D is a gain-of-function mutation in the UNI gene and uni-1D mutants exhibit early termination of inflorescence stem growth and also formation of extra AMs at leaf axils. The former defect involves modulation of the SAM activity and is suppressed by er mutation. Though the AM phenotype is not affected by a single er mutation, it is suppressed by simultaneous mutations of ER-family members. It was previously shown that trans-zeatin (tZ)-type cytokinins were involved in the morphological phenotypes of uni-1D mutants and that expression of CYP735A2, which is essential for biosynthesis of tZ-type cytokinins, was modulated in uni-1D mutants. We show that this modulation of CYP735A2 expression requires activities of ER-family members. Moreover, the ER activity in UNI-expressing cells contributes to all morphological phenotypes of uni-1D mutants, suggesting that a cross-talk between ER-family-dependent and UNI-triggered signaling pathways plays a significant role in the morphological alterations observed in uni-1D mutants.

  14. 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.

  15. [ABA accumulation and distribution during the leaf tissues shows its role stomatal conductance regulation under short-term salinity].

    PubMed

    Akhiiarova, G R; Fricke, W; Veselov, D S; Kudoiarova, G R; Veselov, S Iu

    2006-01-01

    The regulative role of ABA in the rapid plant stomatal reactions in response to salinity was investigated. The influence of the short-term salinity on the overall ABA accumulation and its distribution within the mature leaf (revealed by immunohystochemical technique) and stomatal conductance of barley (Hordeum vulgare L.) were determined. Rapid bulk leaf ABA accumulation and increase in ABA immunolabeling in the mesophyl and guard cells of stomata were shown. The bulk ABA increasing in mature barley leaves coincided with stomatal closure induced by salt treatment indicating on the ABA contribution to the rapid stomatal closure.

  16. HER Family Receptors are Important Theranostic Biomarkers for Cervical Cancer: Blocking Glucose Metabolism Enhances the Therapeutic Effect of HER Inhibitors

    PubMed Central

    Martinho, Olga; Silva-Oliveira, Renato; Cury, Fernanda P.; Barbosa, Ana Martins; Granja, Sara; Evangelista, Adriane Feijó; Marques, Fábio; Miranda-Gonçalves, Vera; Cardoso-Carneiro, Diana; de Paula, Flávia E.; Zanon, Maicon; Scapulatempo-Neto, Cristovam; Moreira, Marise A.R.; Baltazar, Fátima; Longatto-Filho, Adhemar; Reis, Rui Manuel

    2017-01-01

    Persistent HPV infection alone is not sufficient for cervical cancer development, which requires additional molecular alterations for tumor progression and metastasis ultimately leading to a lethal disease. In this study, we performed a comprehensive analysis of HER family receptor alterations in cervical adenocarcinoma. We detected overexpression of HER protein, mainly HER2, which was an independent prognostic marker for these patients. By using in vitro and in vivo approaches, we provided evidence that HER inhibitors, allitinib and lapatinib, were effective in reducing cervical cancer aggressiveness. Furthermore, combination of these drugs with glucose uptake blockers could overcome the putative HIF1-α-mediated resistance to HER-targeted therapies. Thus, we propose that the use of HER inhibitors in association with glycolysis blockers can be a potentially effective treatment option for HER-positive cervical cancer patients. PMID:28255362

  17. A family of human receptors structurally related to Drosophila Toll

    PubMed Central

    Rock, Fernando L.; Hardiman, Gary; Timans, Jackie C.; Kastelein, Robert A.; Bazan, J. Fernando

    1998-01-01

    The discovery of sequence homology between the cytoplasmic domains of Drosophila Toll and human interleukin 1 receptors has sown the conviction that both molecules trigger related signaling pathways tied to the nuclear translocation of Rel-type transcription factors. This conserved signaling scheme governs an evolutionarily ancient immune response in both insects and vertebrates. We report the molecular cloning of a class of putative human receptors with a protein architecture that is similar to Drosophila Toll in both intra- and extracellular segments. Five human Toll-like receptors—named TLRs 1–5—are probably the direct homologs of the fly molecule and, as such, could constitute an important and unrecognized component of innate immunity in humans. Intriguingly, the evolutionary retention of TLRs in vertebrates may indicate another role—akin to Toll in the dorsoventralization of the Drosophila embryo—as regulators of early morphogenetic patterning. Multiple tissue mRNA blots indicate markedly different patterns of expression for the human TLRs. By using fluorescence in situ hybridization and sequence-tagged site database analyses, we also show that the cognate Tlr genes reside on chromosomes 4 (TLRs 1, 2, and 3), 9 (TLR4), and 1 (TLR5). Structure prediction of the aligned Toll-homology domains from varied insect and human TLRs, vertebrate interleukin 1 receptors and MyD88 factors, and plant disease-resistance proteins recognizes a parallel β/α fold with an acidic active site; a similar structure notably recurs in a class of response regulators broadly involved in transducing sensory information in bacteria. PMID:9435236

  18. Functional Evolution of a Multigene Family: Orthologous and Paralogous Pheromone Receptor Genes in the Turnip Moth, Agrotis segetum

    PubMed Central

    Zhang, Dan-Dan; Löfstedt, Christer

    2013-01-01

    Lepidopteran pheromone receptors (PRs), for which orthologies are evident among closely related species, provide an intriguing example of gene family evolution in terms of how new functions may arise. However, only a limited number of PRs have been functionally characterized so far and thus evolutionary scenarios suffer from elements of speculation. In this study we investigated the turnip moth Agrotis segetum, in which female moths produce a mixture of chemically related pheromone components that elicit specific responses from receptor cells on male antennae. We cloned nine A. segetum PR genes and the Orco gene by degenerate primer based RT-PCR. The nine PR genes, named as AsegOR1 and AsegOR3-10, fall into four distinct orthologous clusters of known lepidopteran PRs, of which one contains six paralogues. The paralogues are under relaxed selective pressure, contrasting with the purifying selection on other clusters. We identified the receptors AsegOR9, AsegOR4 and AsegOR5, specific for the respective homologous pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl and (Z)-9-tetradecenyl acetates, by two-electrode voltage clamp recording from Xenopus laevis oocytes co-expressing Orco and each PR candidate. These receptors occur in three different orthologous clusters. We also found that the six paralogues with high sequence similarity vary dramatically in ligand selectivity and sensitivity. Different from AsegOR9, AsegOR6 showed a relatively large response to the behavioural antagonist (Z)-5-decenol, and a small response to (Z)-5-decenyl acetate. AsegOR1 was broadly tuned, but most responsive to (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate and the behavioural antagonist (Z)-8-dodecenyl acetate. AsegOR8 and AsegOR7, which differ from AsegOR6 and AsegOR1 by 7 and 10 aa respectively, showed much lower sensitivities. AsegOR10 showed only small responses to all the tested compounds. These results suggest that new receptors arise through gene duplication, and relaxed

  19. Identification and functional analysis of Joka2, a tobacco member of the family of selective autophagy cargo receptors.

    PubMed

    Zientara-Rytter, Katarzyna; Lukomska, Jolanta; Moniuszko, Grzegorz; Gwozdecki, Rafał; Surowiecki, Przemysław; Lewandowska, Małgorzata; Liszewska, Frantz; Wawrzyńska, Anna; Sirko, Agnieszka

    2011-10-01

    Two main mechanisms of protein turnover exist in eukaryotic cells: the ubiquitin-proteasome system and the autophagy-lysosomal pathway. Autophagy is an emerging important constituent of many physiological and pathological processes, such as response to nutrient deficiency, programmed cell death and innate immune response. In mammalian cells the selectivity of autophagy is ensured by the presence of cargo receptors, such as p62/SQSTM1 and NBR1, responsible for sequestration of the ubiquitinated proteins. In plants no selective cargo receptors have been identified yet. The present report indicates that structural and functional homologs of p62 and NBR1 proteins exist in plants. The tobacco protein, named Joka2, has been identified in yeast two-hybrid search as a binding partner of a small coiled-coil protein, a member of UP9/LSU family of unknown function, encoded by the UP9C gene strongly and specifically induced during sulfur deficiency. The typical domains of p62 and NBR1 are conserved in Joka2. Similarly to p62, Joka2-YFP has dual localization (cytosolic speckles and the nucleus); it forms homodimers and interacts with a member of the ATG8 family. Increased expression of Joka2 and ATG8f was observed in roots of tobacco plants grown for two days in nutrient-deficient conditions. Constitutive ectopic expression of Joka2-YFP in tobacco resulted in attenuated response (manifested by lesser yellowing of the leaves) to nutrient deficiency. In conclusion, Joka2, and presumably the process of selective autophagy, might constitute an important part of plant response to environmental stresses.

  20. Identification and functional analysis of Joka2, a tobacco member of the family of selective autophagy cargo receptors

    PubMed Central

    Zientara-Rytter, Katarzyna; Łukomska, Jolanta; Moniuszko, Grzegorz; Gwozdecki, Rafał; Surowiecki, Przemysław; Lewandowska, Małgorzata; Liszewska, Frantz; Wawrzyńska, Anna

    2011-01-01

    Two main mechanisms of protein turnover exist in eukaryotic cells: the ubiquitin-proteasome system and the autophagy-lysosomal pathway. Autophagy is an emerging important constituent of many physiological and pathological processes, such as response to nutrient deficiency, programmed cell death and innate immune response. In mammalian cells the selectivity of autophagy is ensured by the presence of cargo receptors, such as p62/SQSTM1 and NBR1, responsible for sequestration of the ubiquitinated proteins. In plants no selective cargo receptors have been identified yet. The present report indicates that structural and functional homologs of p62 and NBR1 proteins exist in plants. The tobacco protein, named Joka2, has been identified in yeast two-hybrid search as a binding partner of a small coiled-coil protein, a member of UP9/LSU family of unknown function, encoded by the UP9C gene strongly and specifically induced during sulfur deficiency. The typical domains of p62 and NBR1 are conserved in Joka2. Similarly to p62, Joka2-YFP has dual localization (cytosolic speckles and the nucleus); it forms homodimers and interacts with a member of the ATG8 family. Increased expression of Joka2 and ATG8f was observed in roots of tobacco plants grown for two days in nutrient-deficient conditions. Constitutive ectopic expression of Joka2-YFP in tobacco resulted in attenuated response (manifested by lesser yellowing of the leaves) to nutrient deficiency. In conclusion, Joka2, and presumably the process of selective autophagy, might constitute an important part of plant response to environmental stresses. PMID:21670587

  1. Differences in the progesterone receptor contents between familial breast cancers and sporadic breast cancers stratified by patient age.

    PubMed

    Fukutomi, T; Akashi-Tanaka, S

    2001-01-01

    In the present study, we investigated the estrogen (ER) and progesterone receptor (PR) contents of familial breast cancers (FBCs) and compared the findings with those of sporadic breast cancers., stratified by the patients' age. To evaluate the hormone receptor contents of Japanese FBCs, we collected a consecutive series of 250 FBCs and 2,533 sporadic breast cancers (SBCs). These patients were divided into the three groups stratified by the patients' age at initial surgery (group I, under 40 years old; group II, 40-60 years old; group III, over 60 years old). The clinicopathological features of FBCs and SBCs, including ERs and PRs, were analyzed for each group. In all age groups, the PR contents of FBCs were significantly lower than those of SBCs, particularly for group III. In FBCs, the PR content was significantly lower in group III than in groups I or II. In addition, there was a nonsignificant trend towards a high frequency of ER-positive, PR-negative tumors in FBC patients aged 60 years and over. These data indicate that the loss of ER function and/or loss of binding capacity of PR to progesterone was associated with some late-onset FBCS.

  2. Expression profiles of relaxin family peptides and their receptors indicate their influence on spermatogenesis in the domestic cat (Felis catus).

    PubMed

    Braun, B C; Müller, K; Jewgenow, K

    2015-07-01

    Disturbed spermatogenesis is a common problem in felines. Studying spermatogenesis in the domestic cat can improve the understanding of the biological background and help to counteract fertility problems in other feline species. Here, we analyzed 3 relaxin family peptides (relaxin, relaxin-3, and INSL3) and their receptors (RXFP1, RXFP2, and RXFP3) as potential spermatogenic factors involving their expression in the testis at different stages of its development. It may be concluded from its stage-dependent expression that relaxin, together with RXFP1, appears to be involved in the first stage of spermatogenesis, whereas relaxin-3 via binding to RXFP3 influences spermiogenesis. Furthermore, correlations were observed between relaxin, relaxin-3, RXFP1, RXFP2 and RXFP3 messenger RNA expression, and the relative numbers of haploid cells in testes. The peptide INSL3 was highly expressed at all testis development stages. Because of the low and stage-independent expression of its receptor RXFP2, an auto- and/or paracrine function of INSL3 in spermatogenesis seems unlikely. In the adult testis, messenger RNA expression of relaxin, RXFP1, and RXFP3 predominantly occurs in the tubular testis compartment, whereas INLS3 is mainly expressed in the interstitium.

  3. Abelson Family Tyrosine Kinases Regulate the Function of Nicotinic Acetylcholine Receptors and Nicotinic Synapses on Autonomic NeuronsS⃞

    PubMed Central

    Jayakar, Selwyn S.

    2011-01-01

    Abelson family kinases (AFKs; Abl1, Abl2) are non-receptor tyrosine kinases (NRTKs) implicated in cancer, but they also have important physiological roles that include regulating synaptic structure and function. Recent studies using Abl-deficient mice and the antileukemia drug STI571 [imatinib mesylate (Gleevec); Novartis], which potently and selectively blocks Abl kinase activity, implicate AFKs in regulating presynaptic neurotransmitter release in hippocampus and postsynaptic clustering of nicotinic acetylcholine receptors (nAChRs) in muscle. Here, we tested whether AFKs are relevant for regulating nAChRs and nAChR-mediated synapses on autonomic neurons. AFK immunoreactivity was detected in ciliary ganglion (CG) lysates and neurons, and STI571 application blocked endogenous Abl tyrosine kinase activity. With similar potency, STI571 specifically reduced whole-cell current responses generated by both nicotinic receptor subtypes present on CG neurons (α3*- and α7-nAChRs) and lowered the frequency and amplitude of α3*-nAChR-mediated excitatory postsynaptic currents. Quantal analysis indicated that the synaptic perturbations were postsynaptic in origin, and confocal imaging experiments revealed they were unaccompanied by changes in nAChR clustering or alignment with presynaptic terminals. The results indicate that in autonomic neurons, Abl kinase activity normally supports postsynaptic nAChR function to sustain nAChR-mediated neurotransmission. Such consequences contrast with the influence of Abl kinase activity on presynaptic function and synaptic structure in hippocampus and muscle, respectively, demonstrating a cell-specific mechanism of action. Finally, because STI571 potently inhibits Abl kinase activity, the autonomic dysfunction side effects associated with its use as a chemotherapeutic agent may result from perturbed α3*- and/or α7-nAChR function. PMID:21502378

  4. Involvement of purinergic receptors and NOD-like receptor-family protein 3-inflammasome pathway in the adenosine triphosphate-induced cytokine release from macrophages.

    PubMed

    Gicquel, Thomas; Victoni, Tatiana; Fautrel, Alain; Robert, Sacha; Gleonnec, Florence; Guezingar, Marie; Couillin, Isabelle; Catros, Véronique; Boichot, Elisabeth; Lagente, Vincent

    2014-04-01

    Adenosine triphosphate (ATP) has been described as a danger signal activating the NOD-like receptor-family protein 3 (NLRP3)-inflammasome leading to the pro-inflammatory cytokine, interleukin (IL)-1β, release in the lung. The NLRP3-inflammasome pathway has been previously described to be involved in experimental collagen deposition and the development of pulmonary fibrosis. The aim of the present study was to investigate the role of the NLRP3 inflammasome pathway and P2X7 purinergic receptor in the activation of human macrophages in vitro by ATP. We showed that adenosine 5'-[γ-thio]triphosphate tetralithium salt (ATPγS) and 2',3'-O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzATP), two stable analogs of ATP, are able to potentiate the release of IL-1β from human monocyte-derived macrophages induced by low concentration of lipopolysaccharide (LPS). However, in the same conditions no increase in IL-1α and IL-6 was observed. Immunochemistry has shown that human macrophages natively express NLRP3 and purinergic P2X7 receptors (P2X7 R). NLRP3 and IL-1β mRNA expression were induced from LPS-primed macrophages, but also after 5-h treatment of BzATP as analysed by reverse transcription quantitative polymerase chain reaction. However, other inflammasome pathways (NLRP1, NLRP2, NLRC4, NLRP6 and AIM2) and P2X7 R were not induced by BzATP. We observed that P2X7 R antagonists, A-438079 and A-740003, were able to reduce the release of IL-1β, but not of IL-1α and IL-6 from macrophages stimulated by ATPγS or BzATP. The present results showed the involvement of the P2X7 R-NLRP3 inflammasome pathway in the secretion of IL-1β from ATP-stimulated human macrophages, and suggest that P2X7 R were not involved in IL-1α and IL-6 release. This study also points out that repression of the P2X7 R represents a novel potential therapeutic approach to control fibrosis in lung injury.

  5. Family-based study of the association of the dopamine D2 receptor gene (DRD2) with habitual smoking.

    PubMed

    Bierut, L J; Rice, J P; Edenberg, H J; Goate, A; Foroud, T; Cloninger, C R; Begleiter, H; Conneally, P M; Crowe, R R; Hesselbrock, V; Li, T K; Nurnberger, J I; Porjesz, B; Schuckit, M A; Reich, T

    2000-02-14

    A recent study showed an association between the dopamine D2 receptor gene (DRD2) and smoking. The purpose of this study was to determine if the familial transmission of smoking is linked to variation at the DRD2 locus in a genetically informative sample. Subjects were identified in alcohol treatment centers and their relatives were recruited for study. All subjects were interviewed to assess alcohol dependence, smoking habits, and psychiatric disorders. Two polymorphisms within the DRD2 gene were analyzed, including the TaqIA polymorphism. The sample consisted of 138 nuclear families with at least one offspring with habitual smoking, and analysis was by the transmission disequilibrium test (TDT), which avoids problems due to population stratification. There was no significant difference in the frequency between DRD2 alleles transmitted and not transmitted to habitual smokers. There also was no evidence for unequal transmission of DRD2 alleles for the phenotypes "ever smoker" or comorbid alcohol dependence and habitual smoking. This study does not support linkage of the DRD2 with smoking.

  6. 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 ...

  7. None of the As in ABA Stand for Autism: Dispelling the Myths

    ERIC Educational Resources Information Center

    Dillenburger, Karola; Keenan, Mickey

    2009-01-01

    Interventions that are based on scientific principles of applied behaviour analysis (ABA) are recognised as effective treatments for children with autism spectrum disorder (ASD) by many governments and professionals (Office of the Surgeon General, 2000; Ontario IBI Initiative, 2002). However, many still view ABA as one of many treatments for…

  8. Douglass Developmental Disabilities Center: An ABA Program for Children and Adults with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Handleman, Jan S.; Harris, Sandra L.

    2005-01-01

    There is increasing evidence that Applied Behavior Analysis (ABA) is an effective, and often superior, method to teach children with Autism Spectrum Disorders ASD), than other methods. The Douglass Developmental Disabilities Center of Rutgers University (DDDC) has been using ABA for more than thirty years to teach toddlers, young children,…

  9. 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.

  10. A novel ABA insensitive mutant of Lotus japonicus with a wilty phenotype displays unaltered nodulation regulation.

    PubMed

    Biswas, Bandana; Chan, Pick Kuen; Gresshoff, Peter M

    2009-05-01

    An ABA insensitive mutant, Beyma, was isolated in Lotus japonicus MG-20 from an EMS mutagenesis population using root growth inhibition to applied ABA as the screening criterion. (The name 'Beyma' was taken from the Australian Aboriginal language, Wagiman, beyma, meaning 'drying up'.) The stable mutant that segregates as a dominant Mendelian mutation is insensitive to ABA induced inhibition of germination, vegetative growth, stomatal opening, as well as nodulation. Tissue ABA levels were normal, suggesting a sensitivity rather than biosynthesis mutation. It is slow-growing (50-70% of wild-type MG-20) and has a near-constitutive wilty phenotype associated with its inability to regulate stomatal opening. Whilst showing a wide range of ABA insensitive phenotypes, Beyma did not show alteration of nodule number control, as, in the absence of added ABA, the number and patterning (but not size) of nodules formed in the mutant were similar to that of MG-20. Split root experiments on MG-20 showed that application of ABA on one side of the root inhibited nodulation locally but not systemically. We propose that ABA is not involved directly in systemic autoregulation of nodulation (AON).

  11. Brief Report: Comparative ABA and DIR Trials in Twin Brothers with Autism

    ERIC Educational Resources Information Center

    Hilton, Jane C.; Seal, Brenda C.

    2007-01-01

    Trial interventions in DIR and ABA with twin brothers with autism were offered to help the parents choose one of the programs for their sons. Pre- and post-test scores on the Communication and Symbolic Behavior Scales (CSBS) revealed a slight gain in the composite score of the ABA child and a slight loss in the score of the DIR child. Contrasted…

  12. Antagonistic effect of polyamines on ABA-induced suppression of mitosis in Allium cepa L.

    PubMed

    Mahajan, Arpana; Sharma, Shashi

    2009-02-01

    Effect of abscisic acid (ABA) and polyamines (PAs) [putrescine (Put), spermidine (Spd) and spermine (Spm)] on mitosis in root tips of A. cepa was studied. Treatment with ABA (0.1 to 100 microM) for 24 hr suppressed the mitosis, measured as mitotic index (MI), in a concentration-dependent manner with approx. 50% suppression at 10 microM of ABA. Treatment with different PAs (1 to 100 microM) had differential mitosis suppression effect. Spm was most inhibitory followed by Spd and Put, respectively. The higher concentrations of PAs (1 mM Put; 0.1 and 1 mM Spd or Spm) caused cell distortion. Remarkably, a 24 hr pretreatment of root tips with PAs prior to ABA (100 microM) treatment resulted in a general concentration-dependent reversal of ABA-induced suppression of MI. Catalase (CAT) activity in the root tips, an indicator of redox metabolism, increased due to ABA treatment in a concentration-dependent manner, remained unaltered in response to Put and declined due to Spd and Spm (> or = 0.1 mM). However, all PAs, irrespective of their individual effects, generally antagonized the ABA-dependent increase in CAT activity. Data indicate the possibility of ABA-PA interaction in the regulation of mitosis.

  13. 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.

  14. 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

  15. Exome sequencing deciphers a germline MET mutation in familial epidermal growth factor receptor-mutant lung cancer.

    PubMed

    Tode, Naoki; Kikuchi, Toshiaki; Sakakibara, Tomohiro; Hirano, Taizou; Inoue, Akira; Ohkouchi, Shinya; Tamada, Tsutomu; Okazaki, Tatsuma; Koarai, Akira; Sugiura, Hisatoshi; Niihori, Tetsuya; Aoki, Yoko; Nakayama, Keiko; Matsumoto, Kunio; Matsubara, Yoichi; Yamamoto, Masayuki; Watanabe, Akira; Nukiwa, Toshihiro; Ichinose, Masakazu

    2017-03-13

    Lung cancer accompanied by somatic activating mutations in the epidermal growth factor receptor (EGFR) gene, which is associated with a significant clinical response to the targeted therapy, is frequently found in never-smoking Asian women with adenocarcinoma. Although this implies genetic factors underlying the carcinogenesis, the etiology remains unclear. To gain insight into the pathogenic mechanisms, we sequenced the exomes in the peripheral-blood DNA from six siblings, four affected and two unaffected siblings, of a kindred with familial EGFR-mutant lung adenocarcinoma. We identified a heterozygous missense mutation in MET proto-oncogene, p.Asn375Lys, in all four affected siblings. Combined with somatic loss of heterozygosity for MET, the higher allele frequency in a Japanese sequencing database supports a causative role of the MET mutation in EGFR-mutant lung cancer. Functional assays showed that the mutation reduces the binding affinity of MET for its ligand, hepatocyte growth factor, and damages the subsequent cellular processes including proliferation, clonogenicity, motility, and tumorigenicity. The MET mutation was further observed to abrogate the ERBB3-mediated AKT signal transduction, which is shared downstream by EGFR. These findings provide an etiological view that the MET mutation is involved in the pathogenesis of EGFR-mutant lung cancer because it generates oncogenic stress that induces compensatory EGFR activation. The identification of MET in a kindred with familial EGFR-mutant lung cancer is insightful to explore the pathogenic mechanism of not only familial, but also sporadic EGFR-mutant lung cancer by underscoring MET-related signaling molecules. This article is protected by copyright. All rights reserved.

  16. Cbl-family ubiquitin ligases and their recruitment of CIN85 are largely dispensable for epidermal growth factor receptor endocytosis

    PubMed Central

    Ahmad, Gulzar; Mohapatra, Bhopal; Schulte, Nancy A.; Nadeau, Scott; Luan, Haitao; Zutshi, Neha; Tom, Eric; Ortega-Cava, Cesar; Tu, Chun; Sanada, Masashi; Ogawa, Seishi; Toews, Myron L.; Band, Vimla; Band, Hamid

    2014-01-01

    Members of the Casitas B-Lineage Lymphoma (Cbl) family (Cbl, Cbl-b and Cbl-c) of ubiquitin ligases serve as negative regulators of receptor tyrosine kinases (RTKs). An essential role of Cbl-family protein-dependent ubiquitination for efficient ligand-induced lysosomal targeting and degradation is now well-accepted. However, a more proximal role of Cbl and Cbl-b as adapters for CIN85-endophilin recruitment to mediate ligand-induced initial internalization of RTKs is supported by some studies but refuted by others. Overexpression and/or incomplete depletion of Cbl proteins in these studies is likely to have contributed to this dichotomy. To address the role of endogenous Cbl and Cbl-b in the internalization step of RTK endocytic traffic, we established Cbl/Cbl-b double-knockout (DKO) mouse embryonic fibroblasts (MEFs) and demonstrated that these cells lack the expression of both Cbl-family members as well as endophilin A, while they express CIN85. We show that ligand-induced ubiquitination of EGFR, as a prototype RTK, was abolished in DKO MEFs, and EGFR degradation was delayed. These traits were reversed by ectopic human Cbl expression. EGFR endocytosis, assessed using the internalization of 125I-labeled or fluorescent EGF, or of EGFR itself, was largely retained in Cbl/Cbl-b DKO compared to wild type MEFs. EGFR internalization was also largely intact in Cbl/Cbl-b depleted MCF-10A human mammary epithelial cell line. Inducible shRNA-mediated knockdown of CIN85 in wild type or Cbl/Cbl-b DKO MEFs had no impact on EGFR internalization. Our findings, establish that, at physiological expression levels, Cbl, Cbl-b and CIN85 are largely dispensable for EGFR internalization. Our results support the model that Cbl-CIN85-endophilin complex is not required for efficient internalization of EGFR, a prototype RTK. PMID:25449262

  17. 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.

  18. Functional dissection of an abscisic acid (ABA)-inducible gene reveals two independent ABA-responsive complexes each containing a G-box and a novel cis-acting element.

    PubMed Central

    Shen, Q; Ho, T H

    1995-01-01

    To elucidate the mechanism by which abscisic acid (ABA) regulates gene expression, the promoter of the barley ABA-responsive HVA22 gene has been analyzed by both loss- and gain-of-function studies. Previous reports indicate that G-box sequences, which are present in genes responding to a variety of environmental and physiological cues, are involved in ABA response. However, our data suggest that G-box sequences are necessary but not sufficient for ABA response. Instead, an ABA response complex consisting of a G-box, namely, ABRE3 (GCCACGTACA), and a novel coupling element, CE1 (TGCCACCGG), is sufficient for high-level ABA induction, and replacement of either of these sequences abolishes ABA responsiveness. We suggest that the interaction between G-box sequences, such as ABRE3 in the HVA22 gene, and CE-type sequences determines the specificity in ABA-regulated gene expression. Our results also demonstrate that the ABA response complex is the minimal promoter unit governing high-level ABA induction; four copies of this 49-bp-long complex linked to a minimal promoter can confer more than 100-fold ABA-induced gene expression. In addition to ABA response complex 1, composed of ABRE3 and CE1, the HVA22 promoter contains another ABA response complex. The ABA responsiveness of this ABA response complex 2 relies on the interaction of G-box (ABRE2; CGCACGTGTC) with another yet unidentified coupling element. These two complexes contribute incrementally to the expression level of HVA22 in response to ABA. PMID:7734964

  19. 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.

  20. 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.

  1. Leaf gas exchange and ABA accumulation in Phaseolus vulgaris genotypes of contrasting drought tolerance

    SciTech Connect

    Bertrand, A.; Castonguay, Y.; Nadeau, P. )

    1991-05-01

    Drought tolerance mechanisms in Phaseolus vulgaris (Pv) are still largely unknown. Gas exchange responses and ABA accumulation were monitored in Pv genotypes differing in their drought adaptation. Higher rates of photosynthesis were observed under well-watered conditions in drought sensitive genotypes. Water stress caused a significant reduction in leaf water potential and photosynthetic rates regardless of drought adaptation. Higher photosynthetic rates were maintained under stress conditions in one drought tolerant genotype. Interestingly water stress caused significant ABA accumulation only in this genotype. Root ABA levels were similar among genotypes and were not modified by water stress. Endogenous levels of free ABA in leaves and roots did not correlated with gas exchange response to water stress. These results differ from previous reports on genotypic variation in ABA accumulation under water stress.

  2. 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

  3. 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

  4. Familial risk for mood disorder and the personality risk factor, neuroticism, interact in their association with frontolimbic serotonin 2A receptor binding.

    PubMed

    Frokjaer, Vibe G; Vinberg, Maj; Erritzoe, David; Baaré, William; Holst, Klaus Kähler; Mortensen, Erik Lykke; Arfan, Haroon; Madsen, Jacob; Jernigan, Terry L; Kessing, Lars Vedel; Knudsen, Gitte Moos

    2010-04-01

    Life stress is a robust risk factor for later development of mood disorders, particularly for individuals at familial risk. Likewise, scoring high on the personality trait neuroticism is associated with an increased risk for mood disorders. Neuroticism partly reflects stress vulnerability and is positively correlated to frontolimbic serotonin 2A (5-HT(2A)) receptor binding. Here, we investigate whether neuroticism interacts with familial risk in relation to frontolimbic 5-HT(2A) receptor binding. Twenty-one healthy twins with a co-twin history of mood disorder and 16 healthy twins without a co-twin history of mood disorder were included. They answered self-report personality questionnaires and underwent [(18)F]altanserin positron emission tomography. We found a significant interaction between neuroticism and familial risk in predicting the frontolimbic 5-HT(2A) receptor binding (p=0.026) in an analysis adjusting for age and body mass index. Within the high-risk group only, neuroticism and frontolimbic 5-HT(2A) receptor binding was positively associated (p=0.0037). In conclusion, our data indicate that familial risk and neuroticism interact in their relation to frontolimbic 5-HT(2A) receptor binding. These findings point at a plausible neurobiological link between genetic and personality risk factors and vulnerability to developing mood disorders. It contributes to our understanding of why some people at high risk develop mood disorders while others do not. We speculate that an increased stress reactivity in individuals at high familial risk for mood disorders might enhance the effect of neuroticism in shaping the impact of potential environmental stress and thereby influence serotonergic neurotransmission.

  5. 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

  6. TISSUE-SPECIFIC VENOUS EXPRESSION OF THE EPH FAMILY RECEPTOR EPHB1 IN THE SKIN VASCULATURE

    PubMed Central

    Li, Wenling; Mukouyama, Yoh-suke

    2013-01-01

    Background The major arteries and veins are formed early during development. The molecular tools to identify arterial and venous endothelial cells improve our understanding of arterial-venous differentiation and branching morphogenesis. Compared to arterial differentiation, relatively little is known about what controls venous development, due to a lack of definitive molecular markers for venous endothelial cells. Results Here we report that the antibody against EphB1, an EphB class receptor, makes it possible to establish a reliable whole-mount immunohistochemical analysis of venous identity with greater resolution than previously possible in embryonic and adult skin vasculature models. EphB1 expression is restricted to the entire venous vasculature throughout embryonic development to adulthood, whereas the previously established venous marker EphB4 is also detectable in lymphatic vasculature. This venous-restricted expression of EphB1 is established after the vascular remodeling of the primary capillary plexus has occurred. Compared to its venous-specific expression in the skin, however, EphB1 is not restricted to the venous vasculature in yolk sac, trunk and lung. Conclusions These studies introduce EphB1 as a new venous-restricted marker in a tissue-specific and time-dependent manner. PMID:23649798

  7. 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.

  8. 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.

  9. 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.

  10. 40 CFR 63.1297 - Standards for slabstock flexible polyurethane foam production-HAP ABA emissions from the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... polyurethane foam production-HAP ABA emissions from the production line. 63.1297 Section 63.1297 Protection of... foam production—HAP ABA emissions from the production line. (a) Each owner or operator of a new or... § 63.1293(a)(1) shall control HAP ABA emissions from the slabstock polyurethane foam production line...

  11. 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

  12. Association of the dopamine receptor D1 gene, DRD1, with inattention symptoms in families selected for reading problems.

    PubMed

    Luca, P; Laurin, N; Misener, V L; Wigg, K G; Anderson, B; Cate-Carter, T; Tannock, R; Humphries, T; Lovett, M W; Barr, C L

    2007-08-01

    Twin studies have provided evidence for shared genetic influences between attention-deficit/hyperactivity disorder (ADHD) and specific reading disabilities (RD), with this overlap being highest for the inattentive symptom dimension of ADHD. Previously, we found evidence for association of the dopamine receptor D1 gene (DRD1) with ADHD, and with the inattentive symptom dimension in particular. This, combined with evidence for working memory (WM) deficits in individuals with RD or ADHD, and the importance of D1 receptors in attentional processes and WM function, suggests that DRD1 may be a common genetic influence underlying both disorders. Here, in a study of 232 families ascertained through probands with reading problems, we tested for association of the DRD1 gene with RD, as a categorical trait, and with quantitative measures of key reading component skills, WM ability, and inattentive symptoms. Although no associations were found with RD, or with reading component skills or verbal WM, we found evidence for association with inattentive behaviour. Specifically, DRD1 Haplotype 3, the haplotype previously found to be associated with inattentive symptoms in ADHD, is also associated with parent- and teacher-reported symptoms of inattention in this sample selected for reading problems (P=0.023 and 0.004, respectively). Together, the replicated finding of Haplotype 3 association with inattentive symptoms in two independent study samples strongly supports a role for DRD1 in attentional ability. Furthermore, the association of DRD1 with inattention, but not with RD, or the other reading and reading-related phenotypes analysed, suggests that DRD1 contributes uniquely to inattention, without overlap for reading ability.

  13. 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.

  14. The alpha1-fetoprotein locus is activated by a nuclear receptor of the Drosophila FTZ-F1 family.

    PubMed Central

    Galarneau, L; Paré, J F; Allard, D; Hamel, D; Levesque, L; Tugwood, J D; Green, S; Bélanger, L

    1996-01-01

    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. PMID:8668203

  15. 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

  16. A novel BRET-based binding assay for interaction studies of relaxin family peptide receptor 3 with its ligands.

    PubMed

    Wang, Jia-Hui; Shao, Xiao-Xia; Hu, Meng-Jun; Wei, Dian; Liu, Ya-Li; Xu, Zeng-Guang; Guo, Zhan-Yun

    2017-02-04

    Relaxin family peptide receptor 3 (RXFP3) is an A-class G protein-coupled receptor that is implicated in the regulation of food intake and stress response upon activation by its cognate agonist relaxin-3. To study its interaction with various ligands, we developed a novel bioluminescence resonance energy transfer (BRET)-based binding assay using the brightest NanoLuc as an energy donor and a newly developed cyan-excitable orange fluorescent protein (CyOFP) as an energy acceptor. An engineered CyOFP without intrinsic cysteine residues but with an introduced cysteine at the C-terminus was overexpressed in Escherichia coli and chemically conjugated to the A-chain N-terminus of an easily labeled chimeric R3/I5 peptide via an intermolecular disulfide linkage. After the CyOFP-conjugated R3/I5 bound to a shortened human RXFP3 (removal of 33 N-terminal residues) fused with the NanoLuc reporter at the N-terminus, high BRET signals were detected. Saturation binding and real-time binding assays demonstrated that this BRET pair retained high binding affinity with fast association/dissociation. Using this BRET pair, binding potencies of various ligands with RXFP3 were conveniently measured through competition binding assays. Thus, the novel BRET-based binding assay facilitates interaction studies of RXFP3 with various ligands. The engineered CyOFP without intrinsic cysteine residues may also be applied to other BRET-based binding assays in future studies.

  17. Synapse organization and modulation via C1q family proteins and their receptors in the central nervous system.

    PubMed

    Matsuda, Keiko

    2016-11-12

    Several C1q family members, related to the C1q complement component are extensively expressed in the central nervous system. Cbln1, which belongs to the Cbln subfamily of C1q proteins and released from cerebellar granule cells, plays an indispensable role in the synapse formation and function at parallel fiber-Purkinje cell synapses. This is achieved by formation of a trans-synaptic tripartite complex which is composed of one unit of the Cbln1 hexamer, monomeric neurexin (NRX) containing a splice site 4 insertion at presynaptic terminals and the postsynaptic GluD2 dimers. Recently an increasing number of soluble or transmembrane proteins have been identified to bind directly to the amino-terminal domains of iGluR and regulate the recruitment and function of iGluRs at synapses. Especially at mossy fiber (MF)-CA3 synapses in the hippocampus, postsynaptic kainate-type glutamate receptors (KARs) are involved in synaptic network activity through their characteristic channel kinetics. C1ql2 and C1ql3, which belong to the C1q-like subfamily of C1q proteins, are produced by MFs and serve as extracellular organizers to recruit functional postsynaptic KAR complexes at MF-CA3 synapses via binding to the amino-terminal domains of GluK2 and GluK4 KAR subunits. In addition, C1ql2 and C1ql3 directly bind to NRX3 containing sequences encoded by exon 25b insertion at splice site 5. In the present review, we highlighted the generality of the strategy by tripartite complex formation of the specific type of NRX and iGluR via C1q family members.

  18. Whole genome sequencing of an African American family highlights toll like receptor 6 variants in Kawasaki disease susceptibility

    PubMed Central

    Veeraraghavan, Narayanan; Levy, Eric; Ribeiro dos Santos, Andre M.; Yang, Hai; Hibberd, Martin L.; Tremoulet, Adriana H.; Harismendy, Olivier; Ohno-Machado, Lucila; Burns, Jane C.

    2017-01-01

    Kawasaki disease (KD) is the most common acquired pediatric heart disease. We analyzed Whole Genome Sequences (WGS) from a 6-member African American family in which KD affected two of four children. We sought rare, potentially causative genotypes by sequentially applying the following WGS filters: sequence quality scores, inheritance model (recessive homozygous and compound heterozygous), predicted deleteriousness, allele frequency, genes in KD-associated pathways or with significant associations in published KD genome-wide association studies (GWAS), and with differential expression in KD blood transcriptomes. Biologically plausible genotypes were identified in twelve variants in six genes in the two affected children. The affected siblings were compound heterozygous for the rare variants p.Leu194Pro and p.Arg247Lys in Toll-like receptor 6 (TLR6), which affect TLR6 signaling. The affected children were also homozygous for three common, linked (r2 = 1) intronic single nucleotide variants (SNVs) in TLR6 (rs56245262, rs56083757 and rs7669329), that have previously shown association with KD in cohorts of European descent. Using transcriptome data from pre-treatment whole blood of KD subjects (n = 146), expression quantitative trait loci (eQTL) analyses were performed. Subjects homozygous for the intronic risk allele (A allele of TLR6 rs56245262) had differential expression of Interleukin-6 (IL-6) as a function of genotype (p = 0.0007) and a higher erythrocyte sedimentation rate at diagnosis. TLR6 plays an important role in pathogen-associated molecular pattern recognition, and sequence variations may affect binding affinities that in turn influence KD susceptibility. This integrative genomic approach illustrates how the analysis of WGS in multiplex families with a complex genetic disease allows examination of both the common disease–common variant and common disease–rare variant hypotheses. PMID:28151979

  19. Familial glucocorticoid receptor haploinsufficiency by non-sense mediated mRNA decay, adrenal hyperplasia and apparent mineralocorticoid excess.

    PubMed

    Bouligand, Jérôme; Delemer, Brigitte; Hecart, Annie-Claude; Meduri, Geri; Viengchareun, Say; Amazit, Larbi; Trabado, Séverine; Fève, Bruno; Guiochon-Mantel, Anne; Young, Jacques; Lombès, Marc

    2010-10-22

    Primary glucocorticoid resistance (OMIM 138040) is a rare hereditary disease that causes a generalized partial insensitivity to glucocorticoid action, due to genetic alterations of the glucocorticoid receptor (GR). Investigation of adrenal incidentalomas led to the discovery of a family (eight affected individuals spanning three generations), prone to cortisol resistance, bilateral adrenal hyperplasia, arterial hypertension and hypokalemia. This phenotype exacerbated over time, cosegregates with the first heterozygous nonsense mutation p.R469[R,X] reported to date for the GR, replacing an arginine (CGA) by a stop (TGA) at amino-acid 469 in the second zinc finger of the DNA-binding domain of the receptor. In vitro, this mutation leads to a truncated 50-kDa GR lacking hormone and DNA binding capacity, devoid of hormone-dependent nuclear translocation and transactivation properties. In the proband's fibroblasts, we provided evidence for the lack of expression of the defective allele in vivo. The absence of detectable mutated GR mRNA was accompanied by a 50% reduction in wild type GR transcript and protein. This reduced GR expression leads to a significantly below-normal induction of glucocorticoid-induced target genes, FKBP5 in fibroblasts. We demonstrated that the molecular mechanisms of glucocorticoid signaling dysfunction involved GR haploinsufficiency due to the selective degradation of the mutated GR transcript through a nonsense-mediated mRNA Decay that was experimentally validated on emetine-treated propositus' fibroblasts. GR haploinsufficiency leads to hypertension due to illicit occupation of renal mineralocorticoid receptor by elevated cortisol rather than to increased mineralocorticoid production reported in primary glucocorticoid resistance. Indeed, apparent mineralocorticoid excess was demonstrated by a decrease in urinary tetrahydrocortisone-tetrahydrocortisol ratio in affected patients, revealing reduced glucocorticoid degradation by renal activity of

  20. Activation of Relaxin Family Receptor 1 from Different Mammalian Species by Relaxin Peptide and Small-Molecule Agonist ML290

    PubMed Central

    Huang, Zaohua; Myhr, Courtney; Bathgate, Ross A. D.; Ho, Brian A.; Bueno, Amaya; Hu, Xin; Xiao, Jingbo; Southall, Noel; Barnaeva, Elena; Agoulnik, Irina U.; Marugan, Juan J.; Ferrer, Marc; Agoulnik, Alexander I.

    2015-01-01

    Relaxin peptide (RLN), which signals through the relaxin family peptide 1 (RXFP1) GPCR receptor, has shown therapeutic effects in an acute heart failure clinical trial. We have identified a small-molecule agonist of human RXFP1, ML290; however, it does not activate the mouse receptor. To find a suitable animal model for ML290 testing and to gain mechanistic insights into the interaction of various ligands with RXFP1, we have cloned rhesus macaque, pig, rabbit, and guinea pig RXFP1s and analyzed their activation by RLN and ML290. HEK293T cells expressing macaque or pig RXFP1 responded to relaxin and ML290 treatment as measured by an increase of cAMP production. Guinea pig RXFP1 responded to relaxin but had very low response to ML290 treatment only at highest concentrations used. The rabbit RXFP1 amino acid sequence was the most divergent, with a number of unique substitutions within the ectodomain and the seven-transmembrane domain (7TM). Two splice variants of rabbit RXFP1 derived through alternative splicing of the fourth exon were identified. In contrast to the other species, rabbit RXFP1s were activated by ML290, but not with human, pig, mouse, or rabbit RLNs. Using FLAG-tagged constructs, we have shown that both rabbit RXFP1 variants are expressed on the cell surface. No binding of human Eu-labeled RLN to rabbit RXFP1 was detected, suggesting that in this species, RXFP1 might be non-functional. We used chimeric rabbit–human and guinea pig–human constructs to identify regions important for RLN or ML290 receptor activation. Chimeras with the human ectodomain and rabbit 7TM domain were activated by RLN, whereas substitution of part of the guinea pig 7TM domain with the human sequence only partially restored ML290 activation, confirming the allosteric mode of action for the two ligands. Our data demonstrate that macaque and pig models can be used for ML290 testing. PMID:26347712

  1. ABA inhibits germination but not dormancy release in mature imbibed seeds of Lolium rigidum Gaud.

    PubMed Central

    Goggin, Danica E.; Steadman, Kathryn J.; Emery, R. J. Neil; Farrow, Scott C.; Benech-Arnold, Roberto L.; Powles, Stephen B.

    2009-01-01

    Dormancy release in imbibed annual ryegrass (Lolium rigidum Gaud.) seeds is promoted in the dark but inhibited in the light. The role of abscisic acid (ABA) in inhibition of dormancy release was found to be negligible, compared with its subsequent effect on germination of dormant and non-dormant seeds. Inhibitors of ABA metabolism had the expected effects on seed germination but did not influence ABA concentration, suggesting that they act upon other (unknown) factors regulating dormancy. Although gibberellin (GA) synthesis was required for germination, the influence of exogenous GA on both germination and dormancy release was minor or non-existent. Embryo ABA concentration was the same following treatments to promote (dark stratification) and inhibit (light stratification) dormancy release; exogenous ABA had no effect on this process. However, the sensitivity of dark-stratified seeds to ABA supplied during germination was lower than that of light-stratified seeds. Therefore, although ABA definitely plays a role in the germination of annual ryegrass seeds, it is not the major factor mediating inhibition of dormancy release in imbibed seeds. PMID:19487389

  2. The Dynamics of Embolism Refilling in Abscisic Acid (ABA)-Deficient Tomato Plants

    PubMed Central

    Secchi, Francesca; Perrone, Irene; Chitarra, Walter; Zwieniecka, Anna K.; Lovisolo, Claudio; Zwieniecki, Maciej A.

    2013-01-01

    Plants are in danger of embolism formation in xylem vessels when the balance between water transport capacity and transpirational demand is compromised. To maintain this delicate balance, plants must regulate the rate of transpiration and, if necessary, restore water transport in embolized vessels. Abscisic acid (ABA) is the dominant long-distance signal responsible for plant response to stress, and it is possible that it plays a role in the embolism/refilling cycle. To test this idea, a temporal analysis of embolism and refilling dynamics, transpiration rate and starch content was performed on ABA-deficient mutant tomato plants. ABA-deficient mutants were more vulnerable to embolism formation than wild-type plants, and application of exogenous ABA had no effect on vulnerability. However, mutant plants treated with exogenous ABA had lower stomatal conductance and reduced starch content in the xylem parenchyma cells. The lower starch content could have an indirect effect on the plant’s refilling activity. The results confirm that plants with high starch content (moderately stressed mutant plants) were more likely to recover from loss of water transport capacity than plants with low starch content (mutant plants with application of exogenous ABA) or plants experiencing severe water stress. This study demonstrates that ABA most likely does not play any direct role in embolism refilling, but through the modulation of carbohydrate content, it could influence the plant’s capacity for refilling. PMID:23263667

  3. Production of ABA responses requires both the nuclear and cytoplasmic functional involvement of PYR1.

    PubMed

    Park, EunJoo; Kim, Tae-Houn

    2017-02-26

    Abscisic acid (ABA) enhances stress tolerant responses in plants against unfavorable environmental conditions. In Arabidopsis, ABA promotes interactions between PYR/PYL/RCARs and PP2C, thereby allowing SnRK2s to phosphorylate downstream components required for the regulation of gene expression or for gating ion channels. Because PYR1 is known to localize to nucleus and cytoplasm it is a question whether nuclear or cytoplasmic PYR1 confer different functions to the ABA signaling pathway, as has been previously shown for regulatory proteins. In order to answer this question, transgenic lines expressing nuclear PYR1 were generated in an ABA insensitive mutant background. Enforced nuclear expression of PYR1 was examined by confocal microscopy and western blot analysis. Physiological analyses of the transgenic lines demonstrated that nuclear PYR1 is sufficient to generate ABA responses, such as, the inhibition of seed germination, root growth inhibition, the induction of gene expression, and stomatal closing movement. However, for the full recovery of ABA responses in the mutant background cytoplasmic PYR1 was required. The study suggests both nuclear and cytoplasmic PYR1 participate in the control of ABA signal transduction.

  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. Validation of functional fetal autonomic brain age score fABAS in 5 min short recordings.

    PubMed

    Hoyer, Dirk; Schneider, Uwe; Kowalski, Eva-Maria; Schmidt, Alexander; Witte, Otto W; Schleußner, Ekkehard; Hatzmann, Wolfgang; Grönemeyer, Dietrich Hw; van Leeuwen, Peter

    2015-11-01

    With the objective of evaluating the functional maturation age and developmental disturbances we have previously introduced the fetal autonomic brain age score (fABAS) using 30 min fetal magnetocardiographic recordings (fMCG, Jena). The score is based on heart rate pattern indices that are related to universal principles of developmental biology. The present work aims at the validation of the fABAS methodology on 5 min recordings from an independent database (fMCG, Bochum).We found high agreement of fABAS obtained from Jena normal fetuses (5 min subsets, n =  364) and Bochum recordings (n =  322, normal fetuses). fABAS of 48 recordings from fetuses with intra-uterine growth restriction (IUGR, Bochum) was reduced in most of the cases, a result consistent with IUGR fetuses from Jena previously reported. fABAS calculated from 5 min snapshots only partly covers the accuracy when compared to fABAS from 30 min recordings. More precise diagnosis requires longer recordings.fABAS obtained from fMCG recordings is a strong candidate for standardized assessment of functional maturation age and developmental disturbances. Even 5 min recordings seem to be valuable for screening for maturation problems.

  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. Chemical Promotion of Endogenous Amounts of ABA in Arabidopsis thaliana by a Natural Product, Theobroxide.

    PubMed

    Yamashita, Yudai; Ota, Maremichi; Inoue, Yutaka; Hasebe, Youko; Okamoto, Masanori; Inukai, Tsuyoshi; Masuta, Chikra; Sakihama, Yasuko; Hashidoko, Yasuyuki; Kojima, Mikiko; Sakakibara, Hitoshi; Inage, Yasuyuki; Takahashi, Kosaku; Yoshihara, Teruhiko; Matsuura, Hideyuki

    2016-05-01

    Plant hormones are a group of structurally diverse small compounds that orchestrate the cellular processes governing proper plant growth and environmental adaptation. To understand the details of hormonal activity, we must study not only their inherent activities but also the cross-talk among plant hormones. In addition to their use in agriculture, plant chemical activators, such as probenazole and uniconazole, have made great contributions to understand hormonal cross-talk. However, the use of plant chemical activators is limited due to the lack of activators for certain hormones. For example, to the best of our knowledge, there are only a few chemical activators previously known to stimulate the accumulation of ABA in plants, such as absinazoles and proanthocyanidins. In many cases, antagonistic effects have been examined in experiments using exogenously applied ABA, although these studies did not account for biologically relevant concentrations. In this report, it was found that a natural product, theobroxide, had potential as a plant chemical activator for stimulating the accumulation of ABA. Using theobroxide, the antagonistic effect of ABA against GAs was proved without exogenously applying ABA or using mutant plants. Our results suggest that ABA levels could be chemically controlled to elicit ABA-dependent biological phenomena.

  8. ABA inhibits germination but not dormancy release in mature imbibed seeds of Lolium rigidum Gaud.

    PubMed

    Goggin, Danica E; Steadman, Kathryn J; Emery, R J Neil; Farrow, Scott C; Benech-Arnold, Roberto L; Powles, Stephen B

    2009-01-01

    Dormancy release in imbibed annual ryegrass (Lolium rigidum Gaud.) seeds is promoted in the dark but inhibited in the light. The role of abscisic acid (ABA) in inhibition of dormancy release was found to be negligible, compared with its subsequent effect on germination of dormant and non-dormant seeds. Inhibitors of ABA metabolism had the expected effects on seed germination but did not influence ABA concentration, suggesting that they act upon other (unknown) factors regulating dormancy. Although gibberellin (GA) synthesis was required for germination, the influence of exogenous GA on both germination and dormancy release was minor or non-existent. Embryo ABA concentration was the same following treatments to promote (dark stratification) and inhibit (light stratification) dormancy release; exogenous ABA had no effect on this process. However, the sensitivity of dark-stratified seeds to ABA supplied during germination was lower than that of light-stratified seeds. Therefore, although ABA definitely plays a role in the germination of annual ryegrass seeds, it is not the major factor mediating inhibition of dormancy release in imbibed seeds.

  9. The dynamics of embolism refilling in abscisic acid (ABA)-deficient tomato plants.

    PubMed

    Secchi, Francesca; Perrone, Irene; Chitarra, Walter; Zwieniecka, Anna K; Lovisolo, Claudio; Zwieniecki, Maciej A

    2012-12-24

    Plants are in danger of embolism formation in xylem vessels when the balance between water transport capacity and transpirational demand is compromised. To maintain this delicate balance, plants must regulate the rate of transpiration and, if necessary, restore water transport in embolized vessels. Abscisic acid (ABA) is the dominant long-distance signal responsible for plant response to stress, and it is possible that it plays a role in the embolism/refilling cycle. To test this idea, a temporal analysis of embolism and refilling dynamics, transpiration rate and starch content was performed on ABA-deficient mutant tomato plants. ABA-deficient mutants were more vulnerable to embolism formation than wild-type plants, and application of exogenous ABA had no effect on vulnerability. However, mutant plants treated with exogenous ABA had lower stomatal conductance and reduced starch content in the xylem parenchyma cells. The lower starch content could have an indirect effect on the plant's refilling activity. The results confirm that plants with high starch content (moderately stressed mutant plants) were more likely to recover from loss of water transport capacity than plants with low starch content (mutant plants with application of exogenous ABA) or plants experiencing severe water stress. This study demonstrates that ABA most likely does not play any direct role in embolism refilling, but through the modulation of carbohydrate content, it could influence the plant's capacity for refilling.

  10. High ambient temperature reverses hypothalamic MC4 receptor overexpression in an animal model of anorexia nervosa.

    PubMed

    Gutiérrez, E; Churruca, I; Zárate, J; Carrera, O; Portillo, M P; Cerrato, M; Vázquez, R; Echevarría, E

    2009-04-01

    The potential involvement of the melanocortin system in the beneficial effects of heat application in rats submitted to activity-based anorexia (ABA), an analogous model of anorexia nervosa (AN), was studied. Once ABA rats had lost 20% of body weight, half of the animals were exposed to a high ambient temperature (HAT) of 32 degrees C, whereas the rest were maintained at 21 degrees C. Control sedentary rats yoked to ABA animals received the same treatment. ABA rats (21 degrees C) showed increased Melanocortin 4 (MC4) receptor and Agouti gene Related Peptide (AgRP) expression, and decreased pro-opiomelanocortin (POMC) mRNA levels (Real Time PCR), with respect to controls. Heat application increased weight gain and food intake, and reduced running rate in ABA rats, when compared with ABA rats at 21 degrees C. However, no changes in body weight and food intake were observed in sedentary rats exposed to heat. Moreover, heat application reduced MC4 receptor, AgRP and POMC expression in ABA rats, but no changes were observed in control rats. These results indicate that hypothalamic MC4 receptor overexpression could occur on the basis of the characteristic hyperactivity, weight loss, and self-starvation of ABA rats, and suggest the involvement of hypothalamic melanocortin neural circuits in behavioural changes shown by AN patients. Changes in AgRP and POMC expression could represent an adaptative response to equilibrate energy balance. Moreover, the fact that HAT reversed hypothalamic MC4 receptor overexpression in ABA rats indicates the involvement of brain melanocortin system in the reported beneficial effects of heat application in AN. A combination of MC4 receptor antagonists and heat application could improve the clinical management of AN.

  11. 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

  12. [Relaxin-3 and relaxin family peptide receptors--from structure to functions of a newly discovered mammalian brain system].

    PubMed

    Kania, Alan; Lewandowski, Marian H; Błasiak, Anna

    2014-01-01

    Relaxin-3, a member of the relaxin peptide family, was discovered in 2001 as a homologue of relaxin--a well-known reproductive hormone. However, it is the brain which turned out to be a major expression site of this newly discovered peptide. Both its molecular structure and expression pattern were shown to be very conserved among vertebrates. Extensive research carried out since the discovery of relaxin-3 contributed to the significant progress in our knowledge regarding this neuropeptide. The endogenous relaxin-3 receptor (RXFP3) was identified and the anatomy of the yet uncharacterized mammalian brain system was described, with nucleus incertus as the main center of relaxin-3 expression. Not only its diffusive projections throughout the whole brain, which reach various brain structures such as the hippocampus, septum, intergeniculate leaflet or amygdala, but also functional studies of the relaxin-3/RXFP3 signaling system, allowed this brain network to be classified as one of the ascending nonspecific brain systems. Thus far, research depicts the connection of relaxin-3 with phenomena such as feeding behavior, spatial memory, sleep/wake cycle or modulation of pituitary gland hormone secretion. Responsiveness of relaxin-3 neurons to stress factors and the strong orexigenic effect exerted by this peptide suggest its participation in modulation of feeding by stress, in particular of the chronic type. The discovery of relaxin-3 opened a new research field which will contribute to our better understanding of the neurobiological basis of feeding disorders.

  13. Identification and Functional Characterization of a Calcium-Sensing Receptor Mutation in an Infant with Familial Hypocalciuric Hypercalcemia

    PubMed Central

    Papadopoulou, Anna; Gole, Evangelia; Melachroinou, Katerina; Meristoudis, Christos; Siahanidou, Tania; Papadimitriou, Anastasios

    2016-01-01

    Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder, associated with inactivating mutations of the calcium-sensing receptor (CaSR). To evaluate the functional significance of a CaSR mutation, identified in a young infant who presented with hypercalcemia and hypocalciuria. The CaSR gene coding sequences were analyzed by polymerase chain reaction amplification and direct sequencing analysis. The mutation identified was introduced by site-directed mutagenesis into a wild-type (WT) CaSR plasmid, and human embryonic kidney 293 T cells were transfected with either the WT or mutant CaSR. The function of the mutated CaSR protein was analyzed by evaluating the free intracellular calcium [(Ca2+)i] response after challenge with extracellular calcium (Ca2+). We identified a heterozygous mutation c.772_773delGTinsA in exon 4 resulting in the substitution of amino acid valine (Val) with amino acid arginine (Arg) and the premature pause of the translation 46 amino acids later (Val258ArgfsTer47). Functional assay showed that cells transfected with the mutant CaSR had a significantly poorer response to extracellular Ca2+ stimulation compared with the WT. We have shown that the c.772_773delGTinsA mutation causes a significant alteration of CaSR function leading to features of FHH in an affected young infant since the first months of life. PMID:27087013

  14. The three members of the selectin receptor family recognize a common carbohydrate epitope, the sialyl Lewis(x) oligosaccharide

    PubMed Central

    1992-01-01

    The selectins (lectin-EGF-complement binding-cell adhesion molecules [LEC-CAMs]) are a family of mammalian receptors implicated in the initial interactions between leukocytes and vascular endothelia, leading to lymphocyte homing, platelet binding, and neutrophil extravasation. The three known selectins, L-selectin (leukocyte adhesion molecule-1 [LECAM-1]), E-selectin (endothelial-leukocyte adhesion molecule-1 [ELAM-1]), and P-selectin (GMP-140) share structural features that include a calcium-dependent lectin domain. The sialyl Lewis(x) carbohydrate epitope has been reported as a ligand for both E- and P-selectins. Although L-selectin has been demonstrated to bind to carbohydrates, structural features of potential mammalian carbohydrate ligand(s) have not been well defined. Using an ELISA developed with a sialyl Lewis(x)-containing glycolipid and an E- selectin-IgG chimera, we have demonstrated the direct binding of the L- selectin-IgG chimera to sialyl Lewis(x). This recognition was calcium dependent, and could be blocked by Mel-14 antibody but not by other antibodies. Recognition was confirmed by the ability of cells expressing the native L-selectin to adhere to immobilized sialyl Lewis(x). These data suggest that the sialyl Lewis(x) oligosaccharide may form the basis of a recognition domain common to all three selectins. PMID:1374413

  15. 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

  16. 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.

  17. Markedly reduced activity of mutant calcium-sensing receptor with an inserted Alu element from a kindred with familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism.

    PubMed Central

    Bai, M; Janicic, N; Trivedi, S; Quinn, S J; Cole, D E; Brown, E M; Hendy, G N

    1997-01-01

    Missense mutations have been identified in the coding region of the extracellular calcium-sensing receptor (CASR) gene and cause human autosomal dominant hypo- and hypercalcemic disorders. The functional effects of several of these mutations have been characterized in either Xenopus laevis oocytes or in human embryonic kidney (HEK293) cells. All of the mutations that have been examined to date, however, cause single putative amino acid substitutions. In this report, we studied a mutant CASR with an Alu-repetitive element inserted at codon 876, which was identified in affected members of families with the hypercalcemic disorders, familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT), to understand how this insertion affects CASR function. After cloning of the Alu-repetitive element into the wild-type CASR cDNA, we transiently expressed the mutant receptor in HEK293 cells. Expression of mutant and wild-type receptors was assessed by Western analysis, and the effects of the mutation on extracellular calcium (Ca2+(o)) and gadolinium (Gd3+(o)) elicited increases in the cytosolic calcium concentration (Ca2+(i)) were examined in fura-2-loaded cells using dual wavelength fluorimetry. The insertion resulted in truncated receptor species that had molecular masses some 30 kD less than that of the wild-type CASR and exhibited no Ca2+(i) responses to either Ca2+(o) or Gd3+(o). A similar result was observed with a mutated CASR truncated at residue 876. However, the Alu mutant receptor had no impact on the function of the coexpressed wild-type receptor. Interestingly, the Alu mutant receptor demonstrated decreased cell surface expression relative to the wild-type receptor, whereas the CASR (A877stop) mutant exhibited increased cell surface expression. Thus, like the missense mutations that have been characterized to date in families with FHH, the Alu insertion in this family is a loss-of-function mutation that produces hypercalcemia by

  18. Twenty years of research on Asr (ABA-stress-ripening) genes and proteins.

    PubMed

    González, Rodrigo M; Iusem, Norberto D

    2014-05-01

    Investigating how plants cope with different abiotic stresses-mainly drought and extreme temperatures-is pivotal for both understanding the underlying signaling pathways and improving genetically engineered crops. Plant cells are known to react defensively to mild and severe dehydration by initiating several signal transduction pathways that result in the accumulation of different proteins, sugar molecules and lipophilic anti-oxidants. Among the proteins that build up under these adverse conditions are members of the ancestral ASR (ABA-stress-ripening) family, which is conserved in the plant kingdom but lacks orthologs in Arabidopsis. This review provides a comprehensive summary of the state of the art regarding ASRs, going back to the original description and cloning of the tomato ASR cDNA. That seminal discovery sparked worldwide interest amongst research groups spanning multiple fields: biochemistry, cell biology, evolution, physiology and epigenetics. As these proteins function as both chaperones and transcription factors; this review also covers the progress made on relevant molecular features that account for these dual roles-including the recent identification of their target genes-which may inspire future basic research. In addition, we address reports of drought-tolerant ASR-transgenic plants of different species, highlighting the influential work of authors taking more biotechnological approaches.

  19. The function and structural influence of selective relaxed constraint at functional intracellular loop3 of 5-HT(1A) serotonin-1 receptor family.

    PubMed

    Dass, J Febin Prabhu; Sudandiradoss, C

    2012-10-25

    Serotonin (5-HT) and its receptors have been involved in critical signal transduction mechanism and deregulation implicated in mood-related disorders. 5-HT activities are mediated through a family of transmembrane spanning serotonin receptors. Both within the family and species, 5-HT receptor protein sequence diversity and 7-transmembrane structural homogeneity have long been intriguing. In this study, we have analyzed the codon site constraint in 5-HT1 subclass receptors from 13 orthologous mammalian mRNA coding sequence. Further, the study was extended to computationally investigate the impact of non-synonymous sites with respect to function and structural significance through sequence homology algorithm and molecular dynamics simulation (MDS). Codon sites with significant posterior probability were observed in 5-HT(1A), 5-HT(1B) and 5-HT(1D) receptor indicating variations in site constraint within the 5-HT1 sub-class genes. In 5-HT(1A) receptor, seven sites were detected at the functional intracellular loop(3) (ICL(3)) with higher substitution rate through Codeml program. Sequence homology algorithm identifies that these sites were functionally tolerant within the mammals representing a selectively relaxed constraint at this domain. On the other hand, the root mean square deviation (rmsd) values from MDS suggest differences in structural conformation of ICL(3) models among the species. Specifically, the human ICL(3) model fluctuation was comparatively more stable than other species. Hence, we argue that these sites may have varying influence in G-proteins coupling and activation of effectors systems through downstream interacting accessory proteins of cell among the species. However, further experimental studies are required to elucidate the precise role and the seeming difference of these sites in 5-HT receptors between species.

  20. 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

  1. The ABA effect on the accumulation of an invertase inhibitor transcript that is driven by the CAMV35S promoter in ARABIDOPSIS.

    PubMed

    Koh, Eun-Ji; Lee, Sung June; Hong, Suk-Whan; Lee, Hoi Seon; Lee, Hojoung

    2008-09-30

    Invertase (beta-D-fructofuranosidase; EC 3.2.1.26) catalyzes the conversion of sucrose into glucose and fructose and is involved in an array of important processes, including phloem unloading, carbon partitioning, the response to pathogens, and the control of cell differentiation and development. Its importance may have caused the invertases to evolve into a multigene family whose members are regulated by a variety of different mechanisms, such as pH, sucrose levels, and inhibitor proteins. Although putative invertase inhibitors in the Arabidopsis genome are easy to locate, few studies have been conducted to elucidate their individual functions in vivo in plant growth and development because of their high redundancy. In this study we assessed the functional role of the putative invertase inhibitors in Arabidopsis by generating transgenic plants harboring a putative invertase inhibitor gene under the control of the CaMV35S promoter. A transgenic plant that expressed high levels of the putative invertase inhibitor transcript when grown under normal conditions was chosen for the current study. To our surprise, the stability of the invertase inhibitor transcripts was shown to be down-regulated by the phytohormone ABA (abscisic acid). It is well established that ABA enhances invertase activity in vivo but the underlying mechanisms are still poorly understood. Our results thus suggest that one way ABA regulates invertase activity is by down-regulating its inhibitor.

  2. Overexpression of Arabidopsis translationally controlled tumor protein gene AtTCTP enhances drought tolerance with rapid ABA-induced stomatal closure.

    PubMed

    Kim, Yong-Min; Han, Yun-Jeong; Hwang, Ok-Jin; Lee, Si-Seok; Shin, Ah-Young; Kim, Soo Young; Kim, Jeong-Il

    2012-06-01

    Translationally controlled tumor protein (TCTP), also termed P23 in human, belongs to a family of calcium- and tubulin-binding proteins, and it is generally regarded as a growth-regulating protein. Recently, Arabidopsis TCTP (AtTCTP) has been reported to function as an important growth regulator in plants. On the other hand, plant TCTP has been suggested to be involved in abiotic stress signaling such as aluminum, salt, and water deficit by a number of microarray or proteomic analyses. In this study, the biological functions of AtTCTP were investigated by using transgenic Arabidopsis plants overexpressing AtTCTP. Interestingly, AtTCTP overexpression enhanced drought tolerance in plants. The expression analysis showed that AtTCTP was expressed in guard cells as well as in actively growing tissues. Physiological studies of the overexpression lines showed increased ABA- and calcium-induced stomatal closure ratios and faster stomatal closing responses to ABA. Furthermore, in vitro protein-protein interaction analysis confirmed the interaction between AtTCTP and microtubules, and microtubule cosedimentation assays revealed that the microtubule binding of AtTCTP increased after calcium treatment. These results demonstrate that the overexpression of AtTCTP confers drought tolerance to plants by rapid ABA-mediated stomatal closure via the interaction with microtubules in which calcium binding enhances the interaction. Collectively, the present results suggest that the plant TCTP has molecular properties similar to animal TCTPs, such as tubulin- and calcium-binding, and that it functions in ABA-mediated stomatal movement, in addition to regulating the growth of plants.

  3. 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.

  4. SYNTHESIS OF A NEW FAMILY OF FLUORINATED BORONATE COMPOUNDS AS ANION RECEPTORS AND STUDIES OF THEIR USE AS ADDITIVES IN LITHIUM BATTERY ELECTROLYTES.

    SciTech Connect

    MCBREEN,J.; LEE,H.S.; YANG,X.Q.

    2001-06-08

    Numerous studies have been done on developing new electrolytes for lithium batteries with high ionic conductivity, and good chemical and electrochemical stability. In addition to the research on new salts and solvents, the use of cation receptors to reduce ion pairing in non-aqueous electrolytes has been considered as an approach to improve the properties of electrolytes. Although both cation and anion receptors enhance the dissociation of ion pairs and increase the conductivity of electrolytes, the use of anion receptors is more attractive for a lithium battery electrolyte because anion receptors increase the lithium transference number in the electrolyte. However, most available neutral anion receptors complex with anions through hydrogen binding and cannot be used in lithium batteries. Recently, we have reported on synthesis of a series of new neutral boron compounds as anion receptors based on the idea that electron-deficient boron would complex the anion of the ion pair. The anion complexation effect of these boron compounds was further enhanced by attaching electron-withdrawing groups. Here we report synthesis of another new family of boronate compounds. The effect of these new compounds on conductivity of lithium salts in non-aqueous solution was studied. The molecular weights of these new boronate compounds are lower than our previously reported boron compounds. Therefore, their effects on conductivity enhancement are superior. They also display high electrochemical stability up to 5 V.

  5. 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

  6. Ligand Receptor-Mediated Regulation of Growth in Plants.

    PubMed

    Haruta, Miyoshi; Sussman, Michael R

    2017-01-01

    Growth and development of multicellular organisms are coordinately regulated by various signaling pathways involving the communication of inter- and intracellular components. To form the appropriate body patterns, cellular growth and development are modulated by either stimulating or inhibiting these pathways. Hormones and second messengers help to mediate the initiation and/or interaction of the various signaling pathways in all complex multicellular eukaryotes. In plants, hormones include small organic molecules, as well as larger peptides and small proteins, which, as in animals, act as ligands and interact with receptor proteins to trigger rapid biochemical changes and induce the intracellular transcriptional and long-term physiological responses. During the past two decades, the availability of genetic and genomic resources in the model plant species, Arabidopsis thaliana, has greatly helped in the discovery of plant hormone receptors and the components of signal transduction pathways and mechanisms used by these immobile but highly complex organisms. Recently, it has been shown that two of the most important plant hormones, auxin and abscisic acid (ABA), act through signaling pathways that have not yet been recognized in animals. For example, auxins stimulate cell elongation by bringing negatively acting transcriptional repressor proteins to the proteasome to be degraded, thus unleashing the gene expression program required for increasing cell size. The "dormancy" inducing hormone, ABA, binds to soluble receptor proteins and inhibits a specific class of protein phosphatases (PP2C), which activates phosphorylation signaling leading to transcriptional changes needed for the desiccation of the seeds prior to entering dormancy. While these two hormone receptors have no known animal counterparts, there are also many similarities between animal and plant signaling pathways. For example, in plants, the largest single gene family in the genome is the protein kinase

  7. 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.

  8. 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.

  9. Ascorbate Alleviates Fe Deficiency-Induced Stress in Cotton (Gossypium hirsutum) by Modulating ABA Levels.

    PubMed

    Guo, Kai; Tu, Lili; Wang, Pengcheng; Du, Xueqiong; Ye, Shue; Luo, Ming; Zhang, Xianlong

    2016-01-01

    Fe deficiency causes significant losses to crop productivity and quality. To understand better the mechanisms of plant responses to Fe deficiency, we used an in vitro cotton ovule culture system. We found that Fe deficiency suppressed the development of ovules and fibers, and led to tissue browning. RNA-seq analysis showed that the myo-inositol and galacturonic acid pathways were activated and cytosolic APX (ascorbate peroxidase) was suppressed in Fe-deficient treated fibers, which increased ASC (ascorbate) concentrations to prevent tissue browning. Suppression of cytosolic APX by RNAi in cotton increased ASC contents and delayed tissue browning by maintaining ferric reduction activity under Fe-deficient conditions. Meanwhile, APX RNAi line also exhibited the activation of expression of iron-regulated transporter (IRT1) and ferric reductase-oxidase2 (FRO2) to adapt to Fe deficiency. Abscisic acid (ABA) levels were significantly decreased in Fe-deficient treated ovules and fibers, while the upregulated expression of ABA biosynthesis genes and suppression of ABA degradation genes in Fe-deficient ovules slowed down the decreased of ABA in cytosolic APX suppressed lines to delay the tissue browning. Moreover, the application of ABA in Fe-deficient medium suppressed the development of tissue browning and completely restored the ferric reduction activity. In addition, ABA 8'-hydroxylase gene (GhABAH1) overexpressed cotton has a decreased level of ABA and shows more sensitivity to Fe deficiency. Based on the results, we speculate that ASC could improve the tolerance to Fe deficiency through activating Fe uptake and maintaining ABA levels in cotton ovules and fibers, which in turn reduces symptom formation.

  10. Ascorbate Alleviates Fe Deficiency-Induced Stress in Cotton (Gossypium hirsutum) by Modulating ABA Levels

    PubMed Central

    Guo, Kai; Tu, Lili; Wang, Pengcheng; Du, Xueqiong; Ye, Shue; Luo, Ming; Zhang, Xianlong

    2017-01-01

    Fe deficiency causes significant losses to crop productivity and quality. To understand better the mechanisms of plant responses to Fe deficiency, we used an in vitro cotton ovule culture system. We found that Fe deficiency suppressed the development of ovules and fibers, and led to tissue browning. RNA-seq analysis showed that the myo-inositol and galacturonic acid pathways were activated and cytosolic APX (ascorbate peroxidase) was suppressed in Fe-deficient treated fibers, which increased ASC (ascorbate) concentrations to prevent tissue browning. Suppression of cytosolic APX by RNAi in cotton increased ASC contents and delayed tissue browning by maintaining ferric reduction activity under Fe-deficient conditions. Meanwhile, APX RNAi line also exhibited the activation of expression of iron-regulated transporter (IRT1) and ferric reductase–oxidase2 (FRO2) to adapt to Fe deficiency. Abscisic acid (ABA) levels were significantly decreased in Fe-deficient treated ovules and fibers, while the upregulated expression of ABA biosynthesis genes and suppression of ABA degradation genes in Fe-deficient ovules slowed down the decreased of ABA in cytosolic APX suppressed lines to delay the tissue browning. Moreover, the application of ABA in Fe-deficient medium suppressed the development of tissue browning and completely restored the ferric reduction activity. In addition, ABA 8′-hydroxylase gene (GhABAH1) overexpressed cotton has a decreased level of ABA and shows more sensitivity to Fe deficiency. Based on the results, we speculate that ASC could improve the tolerance to Fe deficiency through activating Fe uptake and maintaining ABA levels in cotton ovules and fibers, which in turn reduces symptom formation. PMID:28101095

  11. Development of a conditional Mesd (mesoderm development) allele for functional analysis of the low-density lipoprotein receptor-related family in defined tissues.

    PubMed

    Taibi, Andrew V; Lighthouse, Janet K; Grady, Richard C; Shroyer, Kenneth R; Holdener, Bernadette C

    2013-01-01

    The Low-density lipoprotein receptor-Related Protein (LRP) family members are essential for diverse processes ranging from the regulation of gastrulation to the modulation of lipid homeostasis. Receptors in this family bind and internalize a diverse array of ligands in the extracellular matrix (ECM). As a consequence, LRPs regulate a wide variety of cellular functions including, but not limited to lipid metabolism, membrane composition, cell motility, and cell signaling. Not surprisingly, mutations in single human LRPs are associated with defects in cholesterol metabolism and development of atherosclerosis, abnormalities in bone density, or aberrant eye vasculature, and may be a contributing factor in development of Alzheimer's disease. Often, members of this diverse family of receptors perform overlapping roles in the same tissues, complicating the analysis of their function through conventional targeted mutagenesis. Here, we describe development of a mouse Mesd (Mesoderm Development) conditional knockout allele, and demonstrate that ubiquitous deletion of Mesd using Cre-recombinase blocks gastrulation, as observed in the traditional knockout and albino-deletion phenotypes. This conditional allele will serve as an excellent tool for future characterization of the cumulative contribution of LRP members in defined tissues.

  12. Proteomic Plasma Membrane Profiling Reveals an Essential Role for gp96 in the Cell Surface Expression of LDLR Family Members, Including the LDL Receptor and LRP6

    PubMed Central

    2012-01-01

    The endoplasmic reticulum chaperone gp96 is required for the cell surface expression of a narrow range of proteins, including toll-like receptors (TLRs) and integrins. To identify a more comprehensive repertoire of proteins whose cell surface expression is dependent on gp96, we developed plasma membrane profiling (PMP), a technique that combines SILAC labeling with selective cell surface aminooxy-biotinylation. This approach allowed us to compare the relative abundance of plasma membrane (PM) proteins on gp96-deficient versus gp96-reconstituted murine pre-B cells. Analysis of unfractionated tryptic peptides initially identified 113 PM proteins, which extended to 706 PM proteins using peptide prefractionation. We confirmed a requirement for gp96 in the cell surface expression of certain TLRs and integrins and found a marked decrease in cell surface expression of four members of the extended LDL receptor family (LDLR, LRP6, Sorl1 and LRP8) in the absence of gp96. Other novel gp96 client proteins included CD180/Ly86, important in the B-cell response to lipopolysaccharide. We highlight common structural motifs in these client proteins that may be recognized by gp96, including the beta-propeller and leucine-rich repeat. This study therefore identifies the extended LDL receptor family as an important new family of proteins whose cell surface expression is regulated by gp96. PMID:22292497

  13. A common W556S mutation in the LDL receptor gene of Danish patients with familial hypercholesterolemia encodes a transport-defective protein.

    PubMed

    Jensen, H K; Holst, H; Jensen, L G; Jørgensen, M M; Andreasen, P H; Jensen, T G; Andresen, B S; Heath, F; Hansen, P S; Neve, S; Kristiansen, K; Faergeman, O; Kølvraa, S; Bolund, L; Gregersen, N

    1997-05-01

    In a group of unrelated Danish patients with familial hypercholesterolemia (FH) we recently reported two common low-density lipoprotein (LDL) receptor mutations, W23X and W66G, accounting for 30% of the cases. In this study, we describe another common LDL receptor mutation, a G to C transition at cDNA position 1730 in exon 12, causing a tryptophan to serine substitution in amino acid position 556 (W556S). In the Danish patients, the W556S mutation was present in 12% of 65 possible mutant alleles. The pathogenicity of the W556S mutation, which is located in one of the five conserved motifs Tyr-Trp-Thr-Asp in the epidermal growth factor homology region, was studied in transfected COS-7 cells expressing normal and mutant LDL receptor cDNAs. Results obtained by immunofluorescence flow cytometry and confocal microscopy, as well as by immunoprecipitation, were compatible with complete retention of the mutant protein in the endoplasmic reticulum. The transport-defective W556S mutation and the W23X and W66G mutations seem to account for about 40% of the LDL receptor defects in Danish families with FH.

  14. Clinical features and growth hormone receptor gene mutations of patients with Laron syndrome from a Chinese family.

    PubMed

    Ying, Yan-Qin; Wei, Hong; Cao, Li-Zhi; Lu, Juan-Juan; Luo, Xiao-Ping

    2007-08-01

    Laron syndrome is an autosomal recessive disorder caused by defects of growth hormone receptor (GHR) gene. It is characterized by severe postnatal growth retardation and characteristic facial features as well as high circulating levels of growth hormone (GH) and low levels of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3). This report described the clinical features and GHR gene mutations in 2 siblings with Laron syndrome in a Chinese family. Their heights and weights were in the normal range at birth, but the growth was retarded after birth. When they presented to the clinic, the heights of the boy (8 years old) and his sister (11 years old) were 80.0 cm (-8.2 SDS) and 96.6 cm (-6.8 SDS) respectively. They had typical appearance features of Laron syndrome such as short stature and obesity, with protruding forehead, saddle nose, large eyes, sparse and thin silky hair and high-pitched voice. They had higher basal serum GH levels and lower serum levels of IGF-I, IGFBP-3 and growth hormone binding protein (GHBP) than normal controls. The peak serum GH level after colonidine and insulin stimulations in the boy was over 350 ng/mL. After one-year rhGH treatment, the boy's height increased from 80.0 cm to 83.3 cm. The gene mutation analysis revealed that two patients had same homozygous mutation of S65H (TCA -->CCA) in exon 4, which is a novel gene mutation. It was concluded that a definite diagnosis of Laron syndrome can be made based on characteristic appearance features and serum levels of GH, IGF-I, IGFBP-3 and GHBP. The S65H mutation might be the cause of Laron syndrome in the two patients.

  15. A Novel RNA-Binding Protein Involves ABA Signaling by Post-transcriptionally Repressing ABI2

    PubMed Central

    Xu, Jianwen; Chen, Yihan; Qian, Luofeng; Mu, Rong; Yuan, Xi; Fang, Huimin; Huang, Xi; Xu, Enshun; Zhang, Hongsheng; Huang, Ji

    2017-01-01

    The Stress Associated RNA-binding protein 1 (SRP1) repressed by ABA, salt and cold encodes a C2C2-type zinc finger protein in Arabidopsis. The knock-out mutation in srp1 reduced the sensitivity of seed to ABA and salt stress during germination and post-germinative growth stages. In contrast, SRP1-overexpressing seedlings were more sensitive to ABA and salt compared to wild type plants. In the presence of ABA, the transcript levels of ABA signaling and germination-related genes including ABI3. ABI5. EM1 and EM6 were less induced in srp1 compared to WT. Interestingly, expression of ABI2 encoding a protein phosphatase 2C protein were significantly up-regulated in srp1 mutants. By in vitro analysis, SRP1 was identified as a novel RNA-binding protein directly binding to 3′UTR of ABI2 mRNA. Moreover, transient expression assay proved the function of SRP1 in reducing the activity of luciferase whose coding sequence was fused with the ABI2 3’UTR. Together, it is suggested that SRP1 is involved in the ABA signaling by post-transcriptionally repressing ABI2 expression in Arabidopsis. PMID:28174577

  16. Role of PP2C-mediated ABA signaling in the moss Physcomitrella patens.

    PubMed

    Sakata, Yoichi; Komatsu, Kenji; Taji, Teruaki; Tanaka, Shigeo

    2009-09-01

    Plant hormone abscisic acid (ABA) is found in a wide range of land plants, from mosses to angiosperms. However, our knowledge concerning the function of ABA is limited to some angiosperm plant species. We have shown that the basal land plant Physcomitrella patens and the model plant Arabidopsis thaliana share a conserved abscisic acid (ABA) signaling pathway mediated through ABI1-related type 2C protein phosphatases (PP2Cs). Ectopic expression of Arabidopsis abi1-1, a dominant allele of ABI1 that functions as a negative regulator of ABA signaling, or targeted disruption of Physcomitrella ABI1-related gene (PpABI1A) resulted in altered ABA sensitivity and abiotic stress tolerance of Physcomitrella, as demonstrated by osmostress and freezing stress. Moreover, transgenic Physcomitrella overexpressing abi1-1 showed altered morphogenesis. These transgenic plants had longer stem lengths compared to the wild type, and continuous growth of archegonia (female organ) with few sporophytes under non-stress conditions. Our results suggest that PP2C-mediated ABA signaling is involved in both the abiotic stress responses and developmental regulation of Physcomitrella.

  17. Down-regulation of cell surface insulin receptor and insulin receptor substrate-1 phosphorylation by inhibitor of 90-kDa heat-shock protein family: endoplasmic reticulum retention of monomeric insulin receptor precursor with calnexin in adrenal chromaffin cells.

    PubMed

    Saitoh, Tomokazu; Yanagita, Toshihiko; Shiraishi, Seiji; Yokoo, Hiroki; Kobayashi, Hideyuki; Minami, Shin-Ichi; Onitsuka, Toshio; Wada, Akihiko

    2002-10-01

    Treatment (>/=6 h) of cultured bovine adrenal chromaffin cells with geldanamycin (GA) or herbimycin A (HA), an inhibitor of the 90-kDa heat-shock protein (Hsp90) family, decreased cell surface (125)I-insulin binding. The effect of GA was concentration (EC(50) = 84 nM)- and time (t(1/2) = 8.5 h)-dependent; GA (1 microM for 24 h) lowered the B(max) value of (125)I-insulin binding by 80%, without changing the K(d) value. Western blot analysis showed that GA (>/=3 h) lowered insulin receptor (IR) level by 83% (t(1/2) = 7.4 h; EC(50) = 74 nM), while raising IR precursor level by 100% (t(1/2) = 7.9 h; EC(50) = 300 nM). Pulse-label followed by reducing and nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that monomeric IR precursor (~190 kDa) developed into the homodimeric IR precursor (approximately 380 kDa) and the mature alpha(2)beta(2) IR (~410 kDa) in nontreated cells, but not in GA-treated cells; in GA-treated cells, the homodimerization-incompetent form of monomeric IR precursor was degraded via endoplasmic reticulum (ER)-associated protein degradation. Immunoprecipitation followed by immunoblot analysis showed that IR precursor was associated with calnexin (CNX) to a greater extent in GA-treated cells, compared with nontreated cells. GA had no effect on IR mRNA levels and internalization rate of cell surface IRs. In GA-treated cells, insulin-induced tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) was attenuated by 77%, with no change in IRS-1 level. Thus, inhibition of the Hsp90 family by GA or HA interrupts homodimerization of monomeric IR precursor in the ER and increases retention of monomeric IR precursor with CNX; this event retards cell surface expression of IR and attenuates insulin-induced activation of IRS-1.

  18. 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

  19. ABA accumulation in water-stressed Citrus roots does not rely on carotenoid content in this organ.

    PubMed

    Manzi, Matías; Lado, Joanna; Rodrigo, María Jesús; Arbona, Vicent; Gómez-Cadenas, Aurelio

    2016-11-01

    Sustained abscisic acid (ABA) accumulation in dehydrated citrus roots depends on the transport from aerial organs. Under this condition, the role of the β,β-carotenoids (ABA precursors) to the de novo synthesis of ABA in roots needs to be clarified since their low availability in this organ restricts its accumulation. To accomplish that, detached citrus roots were exposed to light (to increase their carotenoid content) and subsequently dehydrated (to trigger ABA accumulation). Stress imposition sharply decreased the pool of β,β-carotenoids but, unexpectedly, no concomitant rise in ABA content was observed. Contrastingly, roots of intact plants (with low levels of carotenoids) showed a similar decrease of ABA precursor together with a significant ABA accumulation. Furthermore, upon dehydration both types of roots showed similar upregulation of the key genes involved in biosynthesis of carotenoids and ABA (CsPSY3a; CsβCHX1; CsβCHX2; CsNCED1; CsNCED2), demonstrating a conserved transcriptional response triggered by water stress. Thus, the sharp decrease in root carotenoid levels in response to dehydration should be related to other stress-related signals instead of contributing to ABA biosynthesis. In summary, ABA accumulation in dehydrated-citrus roots largely relies on the presence of the aerial organs and it is independent of the amount of available root β,β-carotenoids.

  20. 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

  1. 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

  2. Orphan Nuclear Receptor NR4A1 Binds a Novel Protein Interaction Site on Anti-apoptotic B Cell Lymphoma Gene 2 Family Proteins.

    PubMed

    Godoi, Paulo H C; Wilkie-Grantham, Rachel P; Hishiki, Asami; Sano, Renata; Matsuzawa, Yasuko; Yanagi, Hiroko; Munte, Claudia E; Chen, Ya; Yao, Yong; Marassi, Francesca M; Kalbitzer, Hans R; Matsuzawa, Shu-Ichi; Reed, John C

    2016-07-01

    B cell lymphoma gene 2 (Bcl-2) family proteins are key regulators of programmed cell death and important targets for drug discovery. Pro-apoptotic and anti-apoptotic Bcl-2 family proteins reciprocally modulate their activities in large part through protein interactions involving a motif known as BH3 (Bcl-2 homology 3). Nur77 is an orphan member of the nuclear receptor family that lacks a BH3 domain but nevertheless binds certain anti-apoptotic Bcl-2 family proteins (Bcl-2, Bfl-1, and Bcl-B), modulating their effects on apoptosis and autophagy. We used a combination of NMR spectroscopy-based methods, mutagenesis, and functional studies to define the interaction site of a Nur77 peptide on anti-apoptotic Bcl-2 family proteins and reveal a novel interaction surface. Nur77 binds adjacent to the BH3 peptide-binding crevice, suggesting the possibility of cross-talk between these discrete binding sites. Mutagenesis of residues lining the identified interaction site on Bcl-B negated the interaction with Nur77 protein in cells and prevented Nur77-mediated modulation of apoptosis and autophagy. The findings establish a new protein interaction site with the potential to modulate the apoptosis and autophagy mechanisms governed by Bcl-2 family proteins.

  3. Reported Early Family Environment Covaries with Menarcheal Age as a Function of Polymorphic Variation in Estrogen Receptor-α (ESR1)

    PubMed Central

    Manuck, Stephen B.; Craig, Anna E.; Flory, Janine D.; Halder, Indrani; Ferrell, Robert E.

    2010-01-01

    Age at menarche, a sentinel index of pubertal maturation, was examined in relation to early family relationships (conflict, cohesion) and polymorphic variation in the gene encoding estrogen receptor-α (ESR1) in a midlife sample of 455 European American women. Consistent with prior literature, women who reported being raised in families characterized by close interpersonal relationships and little conflict tended to reach menarche at a later age than participants reared in families lacking cohesion and prone to discord. Moreover, this association was moderated by ESR1 variation, such that quality of the family environment covaried positively with menarcheal age among participants homozygous for minor alleles of the two ESR1 polymorphisms studied here (rs9304799, rs2234693), but not among women of other ESR1 genotypes. In addition, a) family relationship variables were unrelated to ESR1 variation, and b) genotype-dependent effects of childhood environment on age at menarche could not be accounted for by personality traits elsewhere shown to explain heritable variation in reported family conflict and cohesion. These findings are consistent with theories of differential susceptibility to environmental influence, as well as the more specific hypothesis (by Belsky) that girls differ genetically in their sensitivity to rearing effects on pubertal maturation. PMID:21262040

  4. 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

  5. Hepatitis C Virus Activates a Neuregulin-Driven Circuit to Modify Surface Expression of Growth Factor Receptors of the ErbB Family

    PubMed Central

    Stindt, Sabine; Cebula, Patricia; Albrecht, Ute; Keitel, Verena; Schulte am Esch, Jan; Knoefel, Wolfram T.; Bartenschlager, Ralf; Häussinger, Dieter; Bode, Johannes G.

    2016-01-01

    Recently, the epidermal growth factor (EGF) receptor (EGFR), a member of the ErbB receptor family, and its down-stream signalling have been identified as co-factors for HCV entry and replication. Since EGFR also functions as a heterodimer with other ErbB receptor family members, the subject of the present study was to investigate a possible viral interference with these cellular components. By using genotype 1b replicon cells as well as an infection-based system we found that while transcript and protein levels of EGFR and ErbB2 were up-regulated or unaffected, respectively, HCV induced a substantial reduction of ErbB3 and ErbB4 expression. Down-regulation of ErbB3 expression by HCV involves specificity protein (Sp)1-mediated induction of Neuregulin (NRG)1 expression as well as activation of Akt. Consistently, at transcript level disruption of ErbB3 expression by HCV can be prevented by knockdown of NRG1 or Sp1 expression, whereas reconstitution of ErbB3 protein levels requires inhibition of HCV-induced NRG1 expression and of Akt activity. Interestingly, the NRG1-mediated suppression of ErbB3 expression by HCV results in an enhanced expression of EGFR and ErbB2 on the cell surface, which can be mimicked by siRNA-mediated knockdown of ErbB3 expression. These data delineate a novel mechanism enabling HCV to sway the composition of the ErbB family members on the surface of its host cell by an NRG1-driven circuit and unravels a yet unknown cross-regulation between ErbB3 and the two other family members ErbB2 and EGFR. The shift of the receptor surface expression of the ErbB family towards enhanced expression of ErbB2 and EGFR triggered by HCV was found to promote viral RNA replication and infectivity. This suggests that HCV rearranges expression of ErbB family members to adapt the cellular environment to its requirements. PMID:26886748

  6. A convenient method for europium-labeling of a recombinant chimeric relaxin family peptide R3/I5 for receptor-binding assays.

    PubMed

    Zhang, Wei-Jie; Jiang, Qian; Wang, Xin-Yi; Song, Ge; Shao, Xiao-Xia; Guo, Zhan-Yun

    2013-06-01

    Relaxin family peptides have important biological functions, and so far, four G-protein-coupled receptors have been identified as their receptors (RXFP1-4). A chimeric relaxin family peptide R3/I5, containing the B-chain of relaxin-3 and the A-chain of INSL5, is a selective agonist for both RXFP3 and RXFP4. In a previous study, europium-labeled R3/I5, as a nonradioactive and low-background receptor-binding tracer, was prepared through a chemical synthesis approach. In the present study, we established a convenient alternative approach for preparing the europium-labeled R3/I5 tracer based on a recombinant R3/I5 designed to carry a solubilizing tag at the A-chain N-terminus and a pyroglutamate residue at the B-chain N-terminus. Because of the presence of a single primary amine moiety, the recombinant R3/I5 peptide was site-specifically mono-labeled at the A-chain N-terminus by a diethylenetriaminepentaacetic acid/europium moiety through a convenient one-step procedure. The diethylenetriaminepentaacetic acid/Eu3+-labeled R3/I5 bound both receptors RXFP3 and RXFP4 with high binding affinities and low nonspecific binding. Thus, we have presented a valuable nonradioactive tracer for future interaction studies on RXFP3 and RXFP4 with various natural or designed ligands. The present approach could also be adapted for preparing and labeling of other chimeric relaxin family peptides.

  7. Water deficit effect on ABA accumulation in leaves of two Phaseolus species that differ in drought tolerance

    SciTech Connect

    Janssen, M.G.; Markhart, A.H. )

    1991-05-01

    Phaseolus acutifolius Gray (Pa) is regarded as a dehydration postponer and has stomata that are more sensitive to low leaf water potential than P. vulgaris L. (Pv). This study was designed to determine if the greater sensitivity of Pa stomata is related to greater ABA concentration in Pa or to a greater sensitivity of Pa stomata to ABA. To test these hypotheses bulk leaf ABA accumulation was measured and the sensitivity to ABA was monitored using epidermal strips. To determine if part of the ABA accumulated in the leaves is produced in the roots a novel detached leaf system was used. Stomatal behavior and ABA accumulation at low leaf water potential was monitored and compared to intact leaves. The results of these experiments and the usefulness of the detached leaf system are discussed.

  8. Root water potential integrates discrete soil physical properties to influence ABA signalling during partial rootzone drying.

    PubMed

    Dodd, Ian C; Egea, Gregorio; Watts, Chris W; Whalley, W Richard

    2010-08-01

    To investigate the influence of different growing substrates (two mineral, two organic) on root xylem ABA concentration ([ABA](root)) and the contribution of the drying root system to total sap flow during partial rootzone drying (PRD), sunflower (Helianthus annuus L.) shoots were grafted onto the root systems of two plants grown in separate pots. Sap flow through each hypocotyl was measured below the graft union when one pot ('wet') was watered and other ('dry') was not. Each substrate gave unique relationships between dry pot matric potential (Psi(soil)), volumetric water content ((v)) or penetrometer resistance (Q) and either the fraction of photoperiod sap flow from roots in drying soil or [ABA](root). However, decreased relative sap flow, and increased [ABA](root), from roots in drying soil varied with root water potential (Psi(root)) more similarly across a range of substrates. The gradient between Psi(soil) and Psi(root) was greater in substrates with high sand or peat proportions, which may have contributed to a more sensitive response of [ABA](root) to Psi(soil) in these substrates. Whole plant transpiration was most closely correlated with the mean Psi(soil) of both pots, and then with detached leaf xylem ABA concentration. Although Psi(root) best predicted decreased relative sap flow, and increased [ABA](root), from roots in drying soil across a range of substrates, the inaccessibility of this variable in field studies requires a better understanding of how measurable soil variables (Psi(soil), (v), Q) affect Psi(root).

  9. 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.

  10. Bidirectional regulation of synaptic plasticity in the basolateral amygdala induced by the D1-like family of dopamine receptors and group II metabotropic glutamate receptors

    PubMed Central

    Li, Chenchen; Rainnie, Donald G

    2014-01-01

    Competing mechanisms of long-term potentiation (LTP) and long-term depression (LTD) in principal neurons of the basolateral amygdala (BLA) are thought to underlie the acquisition and consolidation of fear memories, and their subsequent extinction. However, no study to date has examined the locus of action and/or the cellular mechanism(s) by which these processes interact. Here, we report that synaptic plasticity in the cortical pathway onto BLA principal neurons is frequency-dependent and shows a transition from LTD to LTP at stimulation frequencies of ∼10 Hz. At the crossover point from LTD to LTP induction we show that concurrent activation of D1 and group II metabotropic glutamate (mGluR2/3) receptors act to nullify any net change in synaptic strength. Significantly, blockade of either D1 or mGluR2/3 receptors unmasked 10 Hz stimulation-induced LTD and LTP, respectively. Significantly, prior activation of presynaptic D1 receptors caused a time-dependent attenuation of mGluR2/3-induced depotentiation of previously induced LTP. Furthermore, studies with cell type-specific postsynaptic transgene expression of designer receptors activated by designer drugs (DREADDs) suggest that the interaction results via bidirectional modulation of adenylate cyclase activity in presynaptic glutamatergic terminals. The results of our study raise the possibility that the temporal sequence of activation of either presynaptic D1 receptors or mGluR2/3 receptors may critically regulate the direction of synaptic plasticity in afferent pathways onto BLA principal neurons. Hence, the interaction of these two neurotransmitter systems may represent an important mechanism for bidirectional metaplasticity in BLA circuits and thus modulate the acquisition and extinction of fear memory. PMID:25107924

  11. Functional and evolutionary analysis of flatfish gonadotropin receptors reveals cladal- and lineage-level divergence of the teleost glycoprotein receptor family.

    PubMed

    Chauvigné, François; Tingaud-Sequeira, Angèle; Agulleiro, María J; Calusinska, Magdalena; Gómez, Ana; Finn, Roderick Nigel; Cerdà, Joan

    2010-06-01

    Pituitary gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) act via their cognate glycoprotein hormone receptors (GpHRs), FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR) to regulate gonad physiology. Here, we show that the flatfish Senegalese sole (Solea senegalensis) expresses functional isoforms of fshr and lhcgr, but the genomic origin, ligand activation, and tissue distribution of the receptor transcripts are more complex than expected. By integrating the molecular phylogeny of GpHRs with the syntenic loci of vertebrate orthologs, and by subsequently characterizing the physical maps with the phylogeny of flanking genes, we found that vertebrate GpHRs have undergone a divergent evolution. In Teleostei, fshr genes have a common descent and can be classified as fshra, whereas lhcgrb genes exist as alternatively coded genes even in closely related species. Structural analyses of the receptors revealed that Fshra has an elongated ligand-binding domain, containing an extra leucine-rich repeat that specifically arose in the Acanthomorpha because of exon duplication. Ectopic expression in Xenopus laevis oocytes demonstrated that sole Fshra responded to piscine Fsh and Lh, whereas Lhcgrba was preferentially activated by its cognate hormone. The expression pattern of sole fshra and lhcgrba in gonads during the reproductive cycle was consistent with earlier observations wherein Fshra regulates ovarian growth and spermatogenesis and Lhcgrb triggers gamete maturation, respectively. However, contrary to observations in other teleosts, fshra was localized exclusively in Sertoli cells of the testis, whereas lhcgrba was expressed in Leydig cells as well as in spermatids. These results demonstrate the presence of alternatively coded lhcgr isoforms (lhcgrba and lhcgrbb) in teleosts and suggest a role of the lhcgrba receptor in the differentiation of spermatids into spermatozoa in Senegalese sole.

  12. Polymorphic haplotypes and recombination rates at the LDL receptor gene locus in subjects with and without familial hypercholesterolemia who are from different populations.

    PubMed

    Miserez, A R; Schuster, H; Chiodetti, N; Keller, U

    1993-04-01

    RFLPs at the low-density lipoprotein (LDL) receptor locus for TaqI, StuI, HincII, AvaII, ApaLI (5' and 3'), PvuII, and NcoI were studied in Swiss and German families with familial hypercholesterolemia (FH). A total of 1,104 LDL receptor alleles were analyzed using Southern blotting and new PCR-based techniques for detection of the TaqI, StuI, HincII, AvaII, NcoI RFLPs. Two hundred fifty-six independent haplotypes from 368 individuals of 61 unrelated Swiss families, as well as 114 independent haplotypes from 184 subjects of 25 unrelated German families, were constructed. In 76 families, clinical diagnosis of FH was confirmed by cosegregation analysis. Of the 43 unique haplotypes consisting of seven RFLPs detected in the Swiss and Germans, only 9 were common in both population samples. Analysis of linkage disequilibrium revealed nonrandom associations between several of the investigated RFLPs. ApaLI (5'), NcoI, PvuII, TaqI, and AvaII or HincII were particularly informative (cumulative informativeness .85). Relative frequencies, heterozygosity indexes, and PICs of the RFLPs from the Swiss and Germans were compared with values calculated from reported haplotype data for Italians, Icelanders, North American Caucasians, South African Caucasians, and Japanese. Pairwise comparisons of population samples by common RFLPs demonstrated unexpected differences even between geographically adjacent populations (e.g., the Swiss and Germans). Furthermore, genetic distances from the Germans to the other Caucasians were larger than to the Japanese. An unexpected lack of correlation between linkage disequilibria and physical distances was detected for the German and Japanese data, possibly because of nonuniform recombination with excessively high rates between exon 13 and intron 15. Hence, the present study revealed a striking variety of polymorphic haplotypes and heterogeneity of RFLP frequencies and recombination rates among the seven population samples.

  13. Polymorphic haplotypes and recombination rates at the LDL receptor gene locus in subjects with and without familial hypercholesterolemia who are from different populations.

    PubMed Central

    Miserez, A R; Schuster, H; Chiodetti, N; Keller, U

    1993-01-01

    RFLPs at the low-density lipoprotein (LDL) receptor locus for TaqI, StuI, HincII, AvaII, ApaLI (5' and 3'), PvuII, and NcoI were studied in Swiss and German families with familial hypercholesterolemia (FH). A total of 1,104 LDL receptor alleles were analyzed using Southern blotting and new PCR-based techniques for detection of the TaqI, StuI, HincII, AvaII, NcoI RFLPs. Two hundred fifty-six independent haplotypes from 368 individuals of 61 unrelated Swiss families, as well as 114 independent haplotypes from 184 subjects of 25 unrelated German families, were constructed. In 76 families, clinical diagnosis of FH was confirmed by cosegregation analysis. Of the 43 unique haplotypes consisting of seven RFLPs detected in the Swiss and Germans, only 9 were common in both population samples. Analysis of linkage disequilibrium revealed nonrandom associations between several of the investigated RFLPs. ApaLI (5'), NcoI, PvuII, TaqI, and AvaII or HincII were particularly informative (cumulative informativeness .85). Relative frequencies, heterozygosity indexes, and PICs of the RFLPs from the Swiss and Germans were compared with values calculated from reported haplotype data for Italians, Icelanders, North American Caucasians, South African Caucasians, and Japanese. Pairwise comparisons of population samples by common RFLPs demonstrated unexpected differences even between geographically adjacent populations (e.g., the Swiss and Germans). Furthermore, genetic distances from the Germans to the other Caucasians were larger than to the Japanese. An unexpected lack of correlation between linkage disequilibria and physical distances was detected for the German and Japanese data, possibly because of nonuniform recombination with excessively high rates between exon 13 and intron 15. Hence, the present study revealed a striking variety of polymorphic haplotypes and heterogeneity of RFLP frequencies and recombination rates among the seven population samples. PMID:8096361

  14. A new point mutation (C446R) in the thyro