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Sample records for coactivator gcn5 plays

  1. Subunits of ADA-two-A-containing (ATAC) or Spt-Ada-Gcn5-acetyltrasferase (SAGA) Coactivator Complexes Enhance the Acetyltransferase Activity of GCN5.

    PubMed

    Riss, Anne; Scheer, Elisabeth; Joint, Mathilde; Trowitzsch, Simon; Berger, Imre; Tora, László

    2015-11-27

    Histone acetyl transferases (HATs) play a crucial role in eukaryotes by regulating chromatin architecture and locus specific transcription. GCN5 (KAT2A) is a member of the GNAT (Gcn5-related N-acetyltransferase) family of HATs. In metazoans this enzyme is found in two functionally distinct coactivator complexes, SAGA (Spt Ada Gcn5 acetyltransferase) and ATAC (Ada Two A-containing). These two multiprotein complexes comprise complex-specific and shared subunits, which are organized in functional modules. The HAT module of ATAC is composed of GCN5, ADA2a, ADA3, and SGF29, whereas in the SAGA HAT module ADA2b is present instead of ADA2a. To better understand how the activity of human (h) hGCN5 is regulated in the two related, but different, HAT complexes we carried out in vitro HAT assays. We compared the activity of hGCN5 alone with its activity when it was part of purified recombinant hATAC or hSAGA HAT modules or endogenous hATAC or hSAGA complexes using histone tail peptides and full-length histones as substrates. We demonstrated that the subunit environment of the HAT complexes into which GCN5 incorporates determines the enhancement of GCN5 activity. On histone peptides we show that all the tested GCN5-containing complexes acetylate mainly histone H3K14. Our results suggest a stronger influence of ADA2b as compared with ADA2a on the activity of GCN5. However, the lysine acetylation specificity of GCN5 on histone tails or full-length histones was not changed when incorporated in the HAT modules of ATAC or SAGA complexes. Our results thus demonstrate that the catalytic activity of GCN5 is stimulated by subunits of the ADA2a- or ADA2b-containing HAT modules and is further increased by incorporation of the distinct HAT modules in the ATAC or SAGA holo-complexes.

  2. Cloning of SmNCoA-62, a novel nuclear receptor co-activator from Schistosoma mansoni: assembly of a complex with a SmRXR1/SmNR1 heterodimer, SmGCN5 and SmCBP1.

    PubMed

    Fantappié, Marcelo Rosado; Bastos de Oliveira, Francisco Meirelles; de Moraes Maciel, Renata; Rumjanek, Franklin David; Wu, Wenjie; Loverde, Philip T

    2008-08-01

    The Schistosoma mansoni nuclear receptors (NR) SmRXR1 and SmNR1 have recently been shown to form a heterodimer and to bind to canonic hormone response DNA elements. Recruitment of co-regulatory proteins to NRs is required for their transcriptional and biological activities. Here, we cloned a novel S. mansoni NR co-activator, SmNCoA-62. SmNCoA-62 is highly homologous to the human Vitamin D receptor co-activator NCoA62/SKIP. SmNCoA-62 contains the SNW nuclear receptor interaction domain and a putative C-terminus transactivation domain. By using in vitro pull-down assays, we fully mapped the interaction domains of S. mansoni NR co-activators, SmNCoA-62, SmGCN5 and SmCBP1 with SmRXR1 and SmNR1, as well as the domains that mediate interactions amongst the co-activators themselves. By mutagenesis analysis, we showed that SmCBP1 LxxLL motif 2 and LxxLL motif 3, but not LxxLL motif 1, were essential to mediate the interactions of SmCBP1 with the EF domains of SmRXR1 and SmNR1. Histone acetyltransferases SmGCN5 and SmCBP1 specifically acetylated the C/D domains of SmRXR1 and SmNR1. In addition, two acetylation sites of SmNR1 were identified. SmGCN5 and SmCBP1 also acetylated SmNCoA-62 but with significant differences in their acetylation activities. Using gel shift analysis, we were able to demonstrate, in vitro, the assembly of the co-activators on the SmRXR1/SmNR1 heterodimer bound to DNA. LxxLL motifs 2 and 3 of SmCBP1 seemed to play a crucial role for the assembly of the co-activators to the DNA-bound SmRXR1/SmNR1 heterodimer.

  3. Protein acetylation sites mediated by Schistosoma mansoni GCN5

    SciTech Connect

    Moraes Maciel, Renata de; Furtado Madeiro da Costa, Rodrigo; Meirelles Bastosde Oliveira, Francisco; Rumjanek, Franklin David; Fantappie, Marcelo Rosado

    2008-05-23

    The transcriptional co-activator GCN5, a histone acetyltransferase (HAT), is part of large multimeric complexes that are required for chromatin remodeling and transcription activation. As in other eukaryotes, the DNA from the parasite Schistosome mansoni is organized into nucleosomes and the genome encodes components of chromatin-remodeling complexes. Using a series of synthetic peptides we determined that Lys-14 of histone H3 was acetylated by the recombinant SmGCN5-HAT domain. SmGCN5 was also able to acetylate schistosome non-histone proteins, such as the nuclear receptors SmRXR1 and SmNR1, and the co-activator SmNCoA-62. Electron microscopy revealed the presence of SmGCN5 protein in the nuclei of vitelline cells. Within the nucleus, SmGCN5 was found to be located in interchromatin granule clusters (IGCs), which are transcriptionally active structures. The data suggest that SmGCN5 is involved in transcription activation.

  4. Function and subcellular localization of Gcn5, a histone acetyltransferase in Candida albicans.

    PubMed

    Chang, Peng; Fan, Xueyi; Chen, Jiangye

    2015-08-01

    Candida albicans is an opportunistic fungal pathogen commonly found in humans. It has the ability to switch reversibly between three growth forms: budding yeast, pseudohypha, and hypha. The transition between yeast and hyphal growth forms is critical for the pathogenesis of C. albicans. During the yeast-to-hypha morphologic transition, gene expression is regulated by transcriptional regulators including histone modifying complexes and chromatin remodeling complexes. We previously reported that Esa1, a catalytic subunit in the histone acetyltransferase complex NuA4, is essential for the hyphal development of C. albicans. In this study, we analyzed the functional roles of Gcn5, a catalytic subunit in the histone acetyltransferase complex SAGA, in C. albicans. Gcn5 is required for the invasive and filamentous growth of C. albicans. Deletion of GCN5 impaired hyphal elongation in sensing serum and attenuated the virulence of C. albicans in a mouse systemic infection model. The C. albicans gcn5/gcn5 mutant cells also exhibited sensitivity to cell wall stress. Functional analysis showed that the HAT domain and Bromodomain in Gcn5 play distinct roles in morphogenesis and cell wall stress response of C. albicans. Our results show that the conserved residue Glu188 is crucial for the Gcn5 HAT activity and for Gcn5 function during filamentous growth. In addition, the subcellular distribution of ectopically expressed GFP-Gcn5 correlates with the different growth states of C. albicans. In stationary phase, Gcn5 accumulated in the nucleus, while during vegetative growth it localized in the cytoplasm in a morpha-independent manner. Our results suggest that the nuclear localization of Gcn5 depends on the existence of its N-terminal NLS and HAT domains.

  5. Proper Gcn5 histone acetyltransferase expression is required for normal anteroposterior patterning of the mouse skeleton.

    PubMed

    Lin, Wenchu; Zhang, Zhijing; Chen, Chih-Hsin; Behringer, Richard R; Dent, Sharon Y R

    2008-06-01

    Histone acetylation plays important roles in gene regulation. However, the functions of individual histone acetyltransferases (HATs) in specific developmental transcription programs are not well defined. To define the functions of Gcn5, a prototypical HAT, during mouse development, we have created a series of mutant Gcn5 alleles. Our previous work revealed that deletion of Gcn5 leads to embryonic death soon after gastrulation. Embryos homozygous for point mutations in the catalytic center of Gcn5 survive longer, but die soon after E16.0 and exhibit defects in cranial neural tube closure. Embryos bearing a hypomorphic Gcn5(flox(neo)) allele also exhibit neural closure defects and die at or soon after birth. We report here that Gcn5(flox(neo)/flox(neo)) and Gcn5(flox(neo)/Delta) embryos exhibit anterior homeotic transformations in lower thoracic and lumbar vertebrae. These defects are accompanied by a shift in the anterior expression boundary of Hoxc8 and Hoxc9. These data provide the first evidence that Gcn5 contributes to Hox gene regulation and is required for normal anteroposterior patterning of the mouse skeleton.

  6. Gcn5 and SAGA Regulate Shelterin Protein Turnover and Telomere Maintenance

    PubMed Central

    Atanassov, Boyko S.; Evrard, Yvonne A.; Multani, Asha S.; Zhang, Zhijing; Tora, László; Devys, Didier; Chang, Sandy; Dent, Sharon Y.R.

    2009-01-01

    SUMMARY Histone acetyltransferases (HATs) play important roles in gene regulation and DNA repair by influencing the accessibility of chromatin to transcription factors and repair proteins. Here we show that deletion of Gcn5 leads to telomere dysfunction in mouse and human cells. Biochemical studies reveal that depletion of Gcn5 or ubiquitin specific protease 22 (Usp22), which is another bona fide component of the Gcn5-containing SAGA complex, increases ubiquitination and turnover of TRF1, a primary component of the telomeric shelterin complex. Inhibition of the proteasome or over expression of USP22 opposes this effect. The USP22 deubiquitinating module requires association with SAGA complexes for activity, and we find that depletion of Gcn5 compromises this association in mammalian cells. Thus, our results indicate that Gcn5 regulates TRF1 levels through effects on Usp22 activity and SAGA integrity. PMID:19683498

  7. Toxoplasma gondii lysine acetyltransferase GCN5-A functions in the cellular response to alkaline stress and expression of cyst genes.

    PubMed

    Naguleswaran, Arunasalam; Elias, Eliana V; McClintick, Jeanette; Edenberg, Howard J; Sullivan, William J

    2010-12-16

    Parasitic protozoa such as the apicomplexan Toxoplasma gondii progress through their life cycle in response to stimuli in the environment or host organism. Very little is known about how proliferating tachyzoites reprogram their expressed genome in response to stresses that prompt development into latent bradyzoite cysts. We have previously linked histone acetylation with the expression of stage-specific genes, but the factors involved remain to be determined. We sought to determine if GCN5, which operates as a transcriptional co-activator by virtue of its histone acetyltransferase (HAT) activity, contributed to stress-induced changes in gene expression in Toxoplasma. In contrast to other lower eukaryotes, Toxoplasma has duplicated its GCN5 lysine acetyltransferase (KAT). Disruption of the gene encoding for TgGCN5-A in type I RH strain did not produce a severe phenotype under normal culture conditions, but here we show that the TgGCN5-A null mutant is deficient in responding to alkaline pH, a common stress used to induce bradyzoite differentiation in vitro. We performed a genome-wide analysis of the Toxoplasma transcriptional response to alkaline pH stress, finding that parasites deleted for TgGCN5-A fail to up-regulate 74% of the stress response genes that are induced 2-fold or more in wild-type. Using chromatin immunoprecipitation, we verify an enrichment of TgGCN5-A at the upstream regions of genes activated by alkaline pH exposure. The TgGCN5-A knockout is also incapable of up-regulating key marker genes expressed during development of the latent cyst form, and is impaired in its ability to recover from alkaline stress. Complementation of the TgGCN5-A knockout restores the expression of these stress-induced genes and reverses the stress recovery defect. These results establish TgGCN5-A as a major contributor to the alkaline stress response in RH strain Toxoplasma.

  8. Toxoplasma gondii Lysine Acetyltransferase GCN5-A Functions in the Cellular Response to Alkaline Stress and Expression of Cyst Genes

    PubMed Central

    Naguleswaran, Arunasalam; Elias, Eliana V.; McClintick, Jeanette; Edenberg, Howard J.; Sullivan, William J.

    2010-01-01

    Parasitic protozoa such as the apicomplexan Toxoplasma gondii progress through their life cycle in response to stimuli in the environment or host organism. Very little is known about how proliferating tachyzoites reprogram their expressed genome in response to stresses that prompt development into latent bradyzoite cysts. We have previously linked histone acetylation with the expression of stage-specific genes, but the factors involved remain to be determined. We sought to determine if GCN5, which operates as a transcriptional co-activator by virtue of its histone acetyltransferase (HAT) activity, contributed to stress-induced changes in gene expression in Toxoplasma. In contrast to other lower eukaryotes, Toxoplasma has duplicated its GCN5 lysine acetyltransferase (KAT). Disruption of the gene encoding for TgGCN5-A in type I RH strain did not produce a severe phenotype under normal culture conditions, but here we show that the TgGCN5-A null mutant is deficient in responding to alkaline pH, a common stress used to induce bradyzoite differentiation in vitro. We performed a genome-wide analysis of the Toxoplasma transcriptional response to alkaline pH stress, finding that parasites deleted for TgGCN5-A fail to up-regulate 74% of the stress response genes that are induced 2-fold or more in wild-type. Using chromatin immunoprecipitation, we verify an enrichment of TgGCN5-A at the upstream regions of genes activated by alkaline pH exposure. The TgGCN5-A knockout is also incapable of up-regulating key marker genes expressed during development of the latent cyst form, and is impaired in its ability to recover from alkaline stress. Complementation of the TgGCN5-A knockout restores the expression of these stress-induced genes and reverses the stress recovery defect. These results establish TgGCN5-A as a major contributor to the alkaline stress response in RH strain Toxoplasma. PMID:21179246

  9. Gcn5 determines the fate of Drosophila germline stem cells through degradation of Cyclin A.

    PubMed

    Liu, Tianqi; Wang, Qi; Li, Wenqing; Mao, Feiyu; Yue, Shanshan; Liu, Sun; Liu, Xiaona; Xiao, Shan; Xia, Laixin

    2017-02-10

    The fluctuating CDK-CYCLIN complex plays a general role in cell-cycle control. Many types of stem cells use unique features of the cell cycle to facilitate asymmetric division. However, the manner in which these features are established remains poorly understood. The cell cycle of Drosophila female germline stem cells (GSCs) is characterized by short G1 and very long G2 phases, making it an excellent model for the study of cell cycle control in stem cell fate determination. Using a Drosophila female GSCs model, we found Gcn5, the first discovered histone acetyltransferase, to maintain germline stem cells in Drosophila ovaries. Results showed that Gcn5 is dispensable for the transcriptional silencing of bam, but interacts with Cyclin A to facilitate proper turnover in GSCs. Results also showed that Gcn5 promotes Cyclin A ubiquitination, which is dependent on its acetylating activity. Finally, results showed that knockdown of Cyclin A rescued the GSC-loss phenotype caused by lack of Gcn5. Collectively, these findings support the conclusion that Gcn5 acts through acetylation to facilitate Cyclin A ubiquitination and proper turnover, thereby determining the fate of GSCs.-Liu, T., Wang, Q., Li, W., Mao, F., Yue, S., Liu, S., Liu, X., Xiao, S., Xia, L. Gcn5 determines the fate of Drosophila germline stem cells through degradation of Cyclin A.

  10. The Histone H3 Acetylase dGcn5 Is a Key Player in Drosophila melanogaster Metamorphosis

    PubMed Central

    Carré, Clément; Szymczak, Dimitri; Pidoux, Josette; Antoniewski, Christophe

    2005-01-01

    Although it has been well established that histone acetyltransferases (HATs) are involved in the modulation of chromatin structure and gene transcription, there is only little information on their developmental role in higher organisms. Gcn5 was the first transcription factor with HAT activity identified in eukaryotes. Here we report the isolation and characterization of Drosophila melanogaster dGcn5 mutants. Null dGcn5 alleles block the onset of both oogenesis and metamorphosis, while hypomorphic dGcn5 alleles impair the formation of adult appendages and cuticle. Strikingly, the dramatic loss of acetylation of the K9 and K14 lysine residues of histone H3 in dGcn5 mutants has no noticeable effect on larval tissues. In contrast, strong cell proliferation defects in imaginal tissues are observed. In vivo complementation experiments revealed that dGcn5 integrates specific functions in addition to chromosome binding and acetylation. Surprisingly, a dGcn5 variant protein with a deletion of the bromodomain, which has been shown to recognize acetylated histones, appears to be fully functional. Our results establish dGcn5 as a major histone H3 acetylase in Drosophila which plays a key role in the control of specific morphogenetic cascades during developmental transitions. PMID:16135811

  11. The p38-interacting Protein (p38IP) Regulates G2/M Progression by Promoting α-Tubulin Acetylation via Inhibiting Ubiquitination-induced Degradation of the Acetyltransferase GCN5*

    PubMed Central

    Liu, Xin; Xiao, Wei; Wang, Xu-Dong; Li, Yue-Fang; Han, Jiahuai; Li, Yingqiu

    2013-01-01

    p38-interacting protein (p38IP) is a component of the GCN5 histone acetyltransferase-containing coactivator complex (GCN5-SAGA complex). It remains unclear whether p38IP or GCN5-SAGA is involved in cell cycle regulation. Using RNA interference to knock down p38IP, we observed that cells were arrested at the G2/M phase, exhibiting accumulation of cyclins, shrunken spindles, and hypoacetylation of α-tubulin. Further analysis revealed that knockdown of p38IP led to proteasome-dependent degradation of GCN5. GCN5 associated with and acetylated α-tubulin, and recovering GCN5 protein levels in p38IP knockdown cells by ectopic expression of GCN5 efficiently reversed α-tubulin hypoacetylation and G2/M arrest. During the G2/M transition, the association of α-tubulin with GCN5 increased, and the acetylation of α-tubulin reached a peak. Biochemical analyses demonstrated that the interaction between p38IP and GCN5 depended on the p38IP N terminus (1–381 amino acids) and GCN5 histone acetyltransferase domain and bromodomain. The p38IP N terminus could effectively reverse p38IP depletion-induced GCN5 degradation, thus recovering α-tubulin acetylation and G2/M progression. p38IP-mediated suppression of GCN5 ubiquitination most likely occurs via nuclear sequestration of GCN5. Our data indicate that the GCN5-SAGA complex is required for G2/M progression, mainly because p38IP promotes the acetylation of α-tubulin by preventing the degradation of GCN5, in turn facilitating the formation of the mitotic spindle. PMID:24220028

  12. A role for Gcn5 in cardiomyocyte differentiation of rat mesenchymal stem cells.

    PubMed

    Li, Li; Zhu, Jing; Tian, Jie; Liu, Xiaoyan; Feng, Chuan

    2010-12-01

    MSCs possess the capacity of self-renewal and potential of differentiation into various kinds of specialized tissue cells including myocardiocytes. From self-renewing to oriented differentiation, chromatin is remodeled into heritable states that allow activation or maintain the repression of regulatory genes, which means specific genes in self-renewing switched off and specific genes in oriented differentiation activated (Bernstein et al. Cell 125:315-326, 2006). These epigenetic states are established and controlled largely by specific patterns of histone posttranslational modifications, in particular, histone acetylation (Li Nat Rev Genet 3:662-673, 2002). In cardiomyocyte differentiation of rat MSCs, we focused on Gcn5, which linked a known transcriptional coactivator with catalytic histone acetyltransferase activity (Brownell et al. Cell 84:843-851, 1996). To clarify participatory in vivo role of Gcn5, using an RNA interference (RNAi) strategy employing shRNA to specifically knockdown Gcn5 expression in MSCs, we found that HAT activity altered dynamically depended on the inhibition of Gcn5 during MSCs differentiation. Chromatin immunoprecipitation (ChIP) assay showed the increased binding of acetyl histone H3 to the early cardiomyocyte-specific genes GATA4 and NKx2.5 promoters in cardiomyocyte differentiation of MSCs by 5-azacytidine inducing, whereas the decreased binding with lower Gcn5 expression. Cell ultrastructure analysis revealed that MSCs induced by 5-azacytidine possess morphological characteristics of cardiomyocyte cells. The shape of MSCs transfected by Gcn5 RNAi was similar to normal MSCs, but the chromatin showed heavy electron-density and a hard-packed structure. This intermediate state of chromatin may be an inactive part of MSCs differentiation. These results demonstrate that Gcn5, possessing acetyltransferase activity, is involved in regulating chromatin configuration around GATA4 and NKx2.5 in cardiomyocyte differentiation of rat MSCs by

  13. The Histone Acetyltransferase GCN5 Expression Is Elevated and Regulated by c-Myc and E2F1 Transcription Factors in Human Colon Cancer

    PubMed Central

    Yin, Yan-Wei; Jin, Hong-Jian; Zhao, Wenjing; Gao, Beixue; Fang, Jiangao; Wei, Junmin; Zhang, Donna D.; Zhang, Jianing; Fang, Deyu

    2017-01-01

    The histone acetyltransferase GCN5 has been suggested to be involved in promoting cancer cell growth. But its role in human colon cancer development remains unknown. Herein we discovered that GCN5 expression is significantly upregulated in human colon adenocarcinoma tissues. We further demonstrate that GCN5 is upregulated in human colon cancer at the mRNA level. Surprisingly, two transcription factors, the oncogenic c-Myc and the proapoptotic E2F1, are responsible for GCN5 mRNA transcription. Knockdown of c-Myc inhibited colon cancer cell proliferation largely through downregulating GCN5 transcription, which can be fully rescued by the ectopic GCN5 expression. In contrast, E2F1 expression induced human colon cancer cell death, and suppression of GCN5 expression in cells with E2F1 overexpression further facilitated cell apoptosis, suggesting that GCN5 expression is induced by E2F1 as a possible negative feedback in suppressing E2F1-mediated cell apoptosis. In addition, suppression of GCN5 with its specific inhibitor CPTH2 inhibited human colon cancer cell growth. Our studies reveal that GCN5 plays a positive role in human colon cancer development, and its suppression holds a great therapeutic potential in antitumor therapy. PMID:26637399

  14. The GCN5-CITED2-PKA signalling module controls hepatic glucose metabolism through a cAMP-induced substrate switch

    PubMed Central

    Sakai, Mashito; Tujimura-Hayakawa, Tomoko; Yagi, Takashi; Yano, Hiroyuki; Mitsushima, Masaru; Unoki-Kubota, Hiroyuki; Kaburagi, Yasushi; Inoue, Hiroshi; Kido, Yoshiaki; Kasuga, Masato; Matsumoto, Michihiro

    2016-01-01

    Hepatic gluconeogenesis during fasting results from gluconeogenic gene activation via the glucagon–cAMP–protein kinase A (PKA) pathway, a process whose dysregulation underlies fasting hyperglycemia in diabetes. Such transcriptional activation requires epigenetic changes at promoters by mechanisms that have remained unclear. Here we show that GCN5 functions both as a histone acetyltransferase (HAT) to activate fasting gluconeogenesis and as an acetyltransferase for the transcriptional co-activator PGC-1α to inhibit gluconeogenesis in the fed state. During fasting, PKA phosphorylates GCN5 in a manner dependent on the transcriptional coregulator CITED2, thereby increasing its acetyltransferase activity for histone and attenuating that for PGC-1α. This substrate switch concomitantly promotes both epigenetic changes associated with transcriptional activation and PGC-1α–mediated coactivation, thereby triggering gluconeogenesis. The GCN5-CITED2-PKA signalling module and associated GCN5 substrate switch thus serve as a key driver of gluconeogenesis. Disruption of this module ameliorates hyperglycemia in obese diabetic animals, offering a potential therapeutic strategy for such conditions. PMID:27874008

  15. Histone acetyltransferase AtGCN5/HAG1 is a versatile regulator of developmental and inducible gene expression in Arabidopsis.

    PubMed

    Servet, Caroline; Conde e Silva, Natalia; Zhou, Dao-Xiu

    2010-07-01

    Histone acetylation/deacetylation is a dynamic process and plays an important role in gene regulation. Histone acetylation homeostasis is regulated by antagonist actions of histone acetyltransferases (HAT) and deacetylases (HDAC). Plant genome encodes multiple HATs and HDACs. The Arabidopsis HAT gene AtGCN5/HAG1plays an essential role in many plant development processes, such as meristem function, cell differentiation, leaf and floral organogenesis, and responses to environmental conditions such as light and cold, indicating an important role of this HAT in the regulation of both long-term developmental switches and short-term inducible gene expression. AtGCN5 targets to a large number of promoters and is required for acetylation of several histone H3 lysine residues. Recruitment of AtGCN5 to target promoters is likely to be mediated by direct or indirect interaction with DNA-binding transcription factors and/or by interaction with acetylated histone lysine residues on the targets. Interplay between AtGCN5 and other HAT and HDAC is demonstrated to control specific regulatory pathways. Analysis of the role of AtGCN5 in light-inducible gene expression suggests a function of AtGCN5 in preparing chromatin commitment for priming inducible gene activation in plants.

  16. Histone H3 Ser10 Phosphorylation-Independent Function of Snf1 and Reg1 Proteins Rescues a gcn5− Mutant in HIS3 Expression

    PubMed Central

    Liu, Yang; Xu, Xinjing; Singh-Rodriguez, Soumya; Zhao, Yan; Kuo, Min-Hao

    2005-01-01

    Gcn5 protein is a prototypical histone acetyltransferase that controls transcription of multiple yeast genes. To identify molecular functions that act downstream of or in parallel with Gcn5 protein, we screened for suppressors that rescue the transcriptional defects of HIS3 caused by a catalytically inactive mutant Gcn5, the E173H mutant. One bypass of Gcn5 requirement gene (BGR) suppressor was mapped to the REG1 locus that encodes a semidominant mutant truncated after amino acid 740. Reg1(1-740) protein does not rescue the complete knockout of GCN5, nor does it suppress other gcn5− defects, including the inability to utilize nonglucose carbon sources. Reg1(1-740) enhances HIS3 transcription while HIS3 promoter remains hypoacetylated, indicating that a noncatalytic function of Gcn5 is targeted by this suppressor protein. Reg1 protein is a major regulator of Snf1 kinase that phosphorylates Ser10 of histone H3. However, whereas Snf1 protein is important for HIS3 expression, replacing Ser10 of H3 with alanine or glutamate neither attenuates nor augments the BGR phenotypes. Overproduction of Snf1 protein also preferentially rescues the E173H allele. Biochemically, both Snf1 and Reg1(1-740) proteins copurify with Gcn5 protein. Snf1 can phosphorylate recombinant Gcn5 in vitro. Together, these data suggest that Reg1 and Snf1 proteins function in an H3 phosphorylation-independent pathway that also involves a noncatalytic role played by Gcn5 protein. PMID:16287868

  17. GCN5 is a required cofactor for a ubiquitin ligase that targets NF-κB/RelA

    PubMed Central

    Mao, Xicheng; Gluck, Nathan; Li, Duo; Maine, Gabriel N.; Li, Haiying; Zaidi, Iram W.; Repaka, Aparna; Mayo, Marty W.; Burstein, Ezra

    2009-01-01

    The transcription factor NF-κB is a critical regulator of inflammatory and cell survival signals. Proteasomal degradation of NF-κB subunits plays an important role in the termination of NF-κB activity, and at least one of the identified ubiquitin ligases is a multimeric complex containing Copper Metabolism Murr1 Domain 1 (COMMD1) and Cul2. We report here that GCN5, a histone acetyltransferase, associates with COMMD1 and other components of the ligase, promotes RelA ubiquitination, and represses κB-dependent transcription. In this role, the acetyltransferase activity of GCN5 is not required. Interestingly, GCN5 binds more avidly to RelA after phosphorylation on Ser 468, an event that is dependent on IKK activity. Consistent with this, we find that both GCN5 and the IκB Kinase (IKK) complex promote RelA degradation. Collectively, the data indicate that GCN5 participates in the ubiquitination process as an accessory factor for a ubiquitin ligase, where it provides a novel link between phosphorylation and ubiquitination. PMID:19339690

  18. Human ATAC Is a GCN5/PCAF-containing acetylase complex with a novel NC2-like histone fold module that interacts with the TATA-binding protein.

    PubMed

    Wang, Yuan-Liang; Faiola, Francesco; Xu, Muyu; Pan, Songqin; Martinez, Ernest

    2008-12-05

    Eukaryotic GCN5 acetyltransferases influence diverse biological processes by acetylating histones and non-histone proteins and regulating chromatin and gene-specific transcription as part of multiprotein complexes. In lower eukaryotes and invertebrates, these complexes include the yeast ADA complex that is still incompletely understood; the SAGA (Spt-Ada-Gcn5 acetylase) complexes from yeast to Drosophila that are mostly coactivators; and the ATAC (Ada Two-A containing) complex, only known in Drosophila and still poorly characterized. In contrast, vertebrate organisms, express two paralogous GCN5-like acetyltransferases (GCN5 and PCAF), which have been found so far only in SAGA-type complexes referred to hereafter as the STAGA (SPT3-TAF9-GCN5/PCAF acetylase) complexes. We now report the purification and characterization of vertebrate (human) ATAC-type complexes and identify novel components of STAGA. We show that human ATAC complexes incorporate in addition to GCN5 or PCAF (GCN5/PCAF), other epigenetic coregulators (ADA2-A, ADA3, STAF36, and WDR5), cofactors of chromatin assembly/remodeling and DNA replication machineries (POLE3/CHRAC17 and POLE4), the stress- and TGFbeta-activated protein kinase (TAK1/MAP3K7) and MAP3-kinase regulator (MBIP), additional cofactors of unknown function, and a novel YEATS2-NC2beta histone fold module that interacts with the TATA-binding protein (TBP) and negatively regulates transcription when recruited to a promoter. We further identify the p38 kinase-interacting protein (p38IP/FAM48A) as a novel component of STAGA with distant similarity to yeast Spt20. These results suggest that vertebrate ATAC-type and STAGA-type complexes link specific extracellular signals to modification of chromatin structure and regulation of the basal transcription machinery.

  19. Distinct but overlapping roles of histone acetylase PCAF and of the closely related PCAF-B/GCN5 in mouse embryogenesis

    PubMed Central

    Yamauchi, Teruo; Yamauchi, Jun; Kuwata, Takeshi; Tamura, Tomohiko; Yamashita, Tsuyoshi; Bae, Nancy; Westphal, Heiner; Ozato, Keiko; Nakatani, Yoshihiro

    2000-01-01

    PCAF plays a role in transcriptional activation, cell-cycle arrest, and cell differentiation in cultured cells. PCAF contributes to transcriptional activation by acetylating chromatin and transcription factors through its intrinsic histone acetylase activity. In this report, we present evidence for the in vivo function of PCAF and the closely related PCAF-B/GCN5. Mice lacking PCAF are developmentally normal without a distinct phenotype. In PCAF null-zygous mice, protein levels of PCAF-B/GCN5 are drastically elevated in lung and liver, where PCAF is abundantly expressed in wild-type mice, suggesting that PCAF-B/GCN5 functionally compensates for PCAF. In contrast, animals lacking PCAF-B/GCN5 die between days 9.5 and 11.5 of gestation. Normally, PCAF-B/GCN5 mRNA is expressed at high levels already by day 8, whereas PCAF mRNA is first detected on day 12.5, which may explain, in part, the distinct knockout phenotypes. These results provide evidence that PCAF and PCAF-B/GCN5 play distinct but functionally overlapping roles in embryogenesis. PMID:11027331

  20. Structural basis for acyl-group discrimination by human Gcn5L2

    PubMed Central

    Ringel, Alison E.; Wolberger, Cynthia

    2016-01-01

    Gcn5 is a conserved acetyltransferase that regulates transcription by acetylating the N-terminal tails of histones. Motivated by recent studies identifying a chemically diverse array of lysine acyl modifications in vivo, the acyl-chain specificity of the acetyltransferase human Gcn5 (Gcn5L2) was examined. Whereas Gcn5L2 robustly catalyzes lysine acetylation, the acyltransferase activity of Gcn5L2 becomes progressively weaker with increasing acyl-chain length. To understand how Gcn5 discriminates between different acyl-CoA molecules, structures of the catalytic domain of human Gcn5L2 bound to propionyl-CoA and butyryl-CoA were determined. Although the active site of Gcn5L2 can accommodate propionyl-CoA and butyryl-CoA without major structural rearrangements, butyryl-CoA adopts a conformation incompatible with catalysis that obstructs the path of the incoming lysine residue and acts as a competitive inhibitor of Gcn5L2 versus acetyl-CoA. These structures demonstrate how Gcn5L2 discriminates between acyl-chain donors and explain why Gcn5L2 has weak activity for acyl moieties that are larger than an acetyl group. PMID:27377381

  1. Coiled-coil coactivators play a structural role mediating interactions in hypoxia-inducible factor heterodimerization

    DOE PAGES

    Guo, Yirui; Scheuermann, Thomas H.; Partch, Carrie L.; ...

    2015-01-27

    The hypoxia-inducible factor complex (HIF-α·aryl hydrocarbon receptor nuclear translocator (ARNT)) requires association with several transcription coactivators for a successful cellular response to hypoxic stress. In addition to the conventional global transcription coactivator CREB-binding protein/p300 (CBP/p300) that binds to the HIF-α transactivation domain, a new group of transcription coactivators called the coiled-coil coactivators (CCCs) interact directly with the second PER-ARNT-SIM (PAS) domain of ARNT (ARNT PAS-B). These less studied transcription coactivators play essential roles in the HIF-dependent hypoxia response, and CCC misregulation is associated with several forms of cancer. To better understand CCC protein recruitment by the heterodimeric HIF transcription factor,more » we used x-ray crystallography, NMR spectroscopy, and biochemical methods to investigate the structure of the ARNT PAS-B domain in complex with the C-terminal fragment of a coiled-coil coactivator protein, transforming acidic coiled-coil coactivator 3 (TACC3). We found that the HIF-2α PAS-B domain also directly interacts with TACC3, motivating an NMR data-derived model suggesting a means by which TACC3 could form a ternary complex with HIF-2α PAS-B and ARNT PAS-B via β-sheet/coiled-coil interactions. Furthermore, these findings suggest that TACC3 could be recruited as a bridge to cooperatively mediate between the HIF-2α PAS-B·ARNT PAS-B complex, thereby participating more directly in HIF-dependent gene transcription than previously anticipated.« less

  2. Coiled-coil coactivators play a structural role mediating interactions in hypoxia-inducible factor heterodimerization

    SciTech Connect

    Guo, Yirui; Scheuermann, Thomas H.; Partch, Carrie L.; Tomchick, Diana R.; Gardner, Kevin H.

    2015-01-27

    The hypoxia-inducible factor complex (HIF-α·aryl hydrocarbon receptor nuclear translocator (ARNT)) requires association with several transcription coactivators for a successful cellular response to hypoxic stress. In addition to the conventional global transcription coactivator CREB-binding protein/p300 (CBP/p300) that binds to the HIF-α transactivation domain, a new group of transcription coactivators called the coiled-coil coactivators (CCCs) interact directly with the second PER-ARNT-SIM (PAS) domain of ARNT (ARNT PAS-B). These less studied transcription coactivators play essential roles in the HIF-dependent hypoxia response, and CCC misregulation is associated with several forms of cancer. To better understand CCC protein recruitment by the heterodimeric HIF transcription factor, we used x-ray crystallography, NMR spectroscopy, and biochemical methods to investigate the structure of the ARNT PAS-B domain in complex with the C-terminal fragment of a coiled-coil coactivator protein, transforming acidic coiled-coil coactivator 3 (TACC3). We found that the HIF-2α PAS-B domain also directly interacts with TACC3, motivating an NMR data-derived model suggesting a means by which TACC3 could form a ternary complex with HIF-2α PAS-B and ARNT PAS-B via β-sheet/coiled-coil interactions. Furthermore, these findings suggest that TACC3 could be recruited as a bridge to cooperatively mediate between the HIF-2α PAS-B·ARNT PAS-B complex, thereby participating more directly in HIF-dependent gene transcription than previously anticipated.

  3. Coiled-coil coactivators play a structural role mediating interactions in hypoxia-inducible factor heterodimerization.

    PubMed

    Guo, Yirui; Scheuermann, Thomas H; Partch, Carrie L; Tomchick, Diana R; Gardner, Kevin H

    2015-03-20

    The hypoxia-inducible factor complex (HIF-α·aryl hydrocarbon receptor nuclear translocator (ARNT)) requires association with several transcription coactivators for a successful cellular response to hypoxic stress. In addition to the conventional global transcription coactivator CREB-binding protein/p300 (CBP/p300) that binds to the HIF-α transactivation domain, a new group of transcription coactivators called the coiled-coil coactivators (CCCs) interact directly with the second PER-ARNT-SIM (PAS) domain of ARNT (ARNT PAS-B). These less studied transcription coactivators play essential roles in the HIF-dependent hypoxia response, and CCC misregulation is associated with several forms of cancer. To better understand CCC protein recruitment by the heterodimeric HIF transcription factor, we used x-ray crystallography, NMR spectroscopy, and biochemical methods to investigate the structure of the ARNT PAS-B domain in complex with the C-terminal fragment of a coiled-coil coactivator protein, transforming acidic coiled-coil coactivator 3 (TACC3). We found that the HIF-2α PAS-B domain also directly interacts with TACC3, motivating an NMR data-derived model suggesting a means by which TACC3 could form a ternary complex with HIF-2α PAS-B and ARNT PAS-B via β-sheet/coiled-coil interactions. These findings suggest that TACC3 could be recruited as a bridge to cooperatively mediate between the HIF-2α PAS-B·ARNT PAS-B complex, thereby participating more directly in HIF-dependent gene transcription than previously anticipated.

  4. Coiled-coil Coactivators Play a Structural Role Mediating Interactions in Hypoxia-inducible Factor Heterodimerization*

    PubMed Central

    Guo, Yirui; Scheuermann, Thomas H.; Partch, Carrie L.; Tomchick, Diana R.; Gardner, Kevin H.

    2015-01-01

    The hypoxia-inducible factor complex (HIF-α·aryl hydrocarbon receptor nuclear translocator (ARNT)) requires association with several transcription coactivators for a successful cellular response to hypoxic stress. In addition to the conventional global transcription coactivator CREB-binding protein/p300 (CBP/p300) that binds to the HIF-α transactivation domain, a new group of transcription coactivators called the coiled-coil coactivators (CCCs) interact directly with the second PER-ARNT-SIM (PAS) domain of ARNT (ARNT PAS-B). These less studied transcription coactivators play essential roles in the HIF-dependent hypoxia response, and CCC misregulation is associated with several forms of cancer. To better understand CCC protein recruitment by the heterodimeric HIF transcription factor, we used x-ray crystallography, NMR spectroscopy, and biochemical methods to investigate the structure of the ARNT PAS-B domain in complex with the C-terminal fragment of a coiled-coil coactivator protein, transforming acidic coiled-coil coactivator 3 (TACC3). We found that the HIF-2α PAS-B domain also directly interacts with TACC3, motivating an NMR data-derived model suggesting a means by which TACC3 could form a ternary complex with HIF-2α PAS-B and ARNT PAS-B via β-sheet/coiled-coil interactions. These findings suggest that TACC3 could be recruited as a bridge to cooperatively mediate between the HIF-2α PAS-B·ARNT PAS-B complex, thereby participating more directly in HIF-dependent gene transcription than previously anticipated. PMID:25627682

  5. Differential Effects of Histone Acetyltransferase GCN5 or PCAF Knockdown on Urothelial Carcinoma Cells

    PubMed Central

    Koutsogiannouli, Evangelia A.; Hader, Christiane; Pinkerneil, Maria; Hoffmann, Michèle J.; Schulz, Wolfgang A.

    2017-01-01

    Disturbances in histone acetyltransferases (HATs) are common in cancers. In urothelial carcinoma (UC), p300 and CBP are often mutated, whereas the GNAT family HATs GCN5 and PCAF (General Control Nonderepressible 5, p300/CBP-Associated Factor) are often upregulated. Here, we explored the effects of specific siRNA-mediated knockdown of GCN5, PCAF or both in four UC cell lines (UCCs). Expression of various HATs and marker proteins was measured by qRT-PCR and western blot. Cellular effects of knockdowns were analyzed by flow cytometry and ATP-, caspase-, and colony forming-assays. GCN5 was regularly upregulated in UCCs, whereas PCAF was variable. Knockdown of GCN5 or both GNATs, but not of PCAF alone, diminished viability and inhibited clonogenic growth in 2/4 UCCs, inducing cell cycle changes and caspase-3/7 activity. PCAF knockdown elicited GCN5 mRNA upregulation. Double knockdown increased c-MYC and MDM2 (Mouse Double Minute 2) in most cell lines. In conclusion, GCN5 upregulation is especially common in UCCs. GCN5 knockdown impeded growth of specific UCCs, whereas PCAF knockdown elicited minor effects. The limited sensitivity towards GNAT knockdown and its variation between the cell lines might be due to compensatory effects including HAT, c-MYC and MDM2 upregulation. Our results predict that developing drugs targeting individual HATs for UC treatment may be challenging. PMID:28678170

  6. The Histone Acetyltransferase Gcn5 Regulates ncRNA-ICR1 and FLO11 Expression during Pseudohyphal Development in Saccharomyces cerevisiae.

    PubMed

    Wang, Long-Chi; Montalvo-Munoz, Fernando; Tsai, Yuan-Chan; Liang, Chung-Yi; Chang, Chun-Chuan; Lo, Wan-Sheng

    2015-01-01

    Filamentous growth is one of the key features of pathogenic fungi during the early infectious phase. The pseudohyphal development of yeast Saccharomyces cerevisiae shares similar characteristics with hyphae elongation in pathogenic fungi. The expression of FLO11 is essential for adhesive growth and filament formation in yeast and is governed by a multilayered transcriptional network. Here we discovered a role for the histone acetyltransferase general control nonderepressible 5 (Gcn5) in regulating FLO11-mediated pseudohyphal growth. The expression patterns of FLO11 were distinct in haploid and diploid yeast under amino acid starvation induced by 3-amino-1,2,4-triazole (3AT). In diploids, FLO11 expression was substantially induced at a very early stage of pseudohyphal development and decreased quickly, but in haploids, it was gradually induced. Furthermore, the transcription factor Gcn4 was recruited to the Sfl1-Flo8 toggle sites at the FLO11 promoter under 3AT treatment. Moreover, the histone acetylase activity of Gcn5 was required for FLO11 induction. Finally, Gcn5 functioned as a negative regulator of the noncoding RNA ICR1, which is known to suppress FLO11 expression. Gcn5 plays an important role in the regulatory network of FLO11 expression via Gcn4 by downregulating ICR1 expression, which derepresses FLO11 for promoting pseudohyphal development.

  7. Snf1p-dependent Spt-Ada-Gcn5-acetyltransferase (SAGA) recruitment and chromatin remodeling activities on the HXT2 and HXT4 promoters.

    PubMed

    van Oevelen, Chris J C; van Teeffelen, Hetty A A M; van Werven, Folkert J; Timmers, H Th Marc

    2006-02-17

    We previously showed that the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex is recruited to the activated HXT2 and HXT4 genes and plays a role in the association of TBP-associated factors. Using the HXT2 and HXT4 genes, we now present evidence for a functional link between Snf1p-dependent activation, recruitment of the SAGA complex, histone H3 removal, and H3 acetylation. Recruitment of the SAGA complex is dependent on the release of Ssn6p-Tup1p repression by Snf1p. In addition, we found that the Gcn5p subunit of the SAGA complex preferentially acetylates histone H3K18 on the HXT2 and HXT4 promoters and that Gcn5p activity is required for removal of histone H3 from the HXT4 promoter TATA region. In contrast, histone H3 removal from the HXT2 promoter does not require Gcn5p. In conclusion, although similar protein complexes are involved, induction of HXT2 and HXT4 displays important mechanistic differences.

  8. Garcinol Inhibits GCN5-Mediated Lysine Acetyltransferase Activity and Prevents Replication of the Parasite Toxoplasma gondii

    PubMed Central

    Jeffers, Victoria; Gao, Hongyu; Checkley, Lisa A.; Liu, Yunlong; Ferdig, Michael T.

    2016-01-01

    Lysine acetylation is a critical posttranslational modification that influences protein activity, stability, and binding properties. The acetylation of histone proteins in particular is a well-characterized feature of gene expression regulation. In the protozoan parasite Toxoplasma gondii, a number of lysine acetyltransferases (KATs) contribute to gene expression and are essential for parasite viability. The natural product garcinol was recently reported to inhibit enzymatic activities of GCN5 and p300 family KATs in other species. Here we show that garcinol inhibits TgGCN5b, the only nuclear GCN5 family KAT known to be required for Toxoplasma tachyzoite replication. Treatment of tachyzoites with garcinol led to a reduction of global lysine acetylation, particularly on histone H3 and TgGCN5b itself. We also performed transcriptome sequencing (RNA-seq), which revealed increasing aberrant gene expression coincident with increasing concentrations of garcinol. The majority of the genes that were most significantly affected by garcinol were also associated with TgGCN5b in a previously reported chromatin immunoprecipitation assay with microarray technology (ChIP-chip) analysis. The dysregulated gene expression induced by garcinol significantly inhibits Toxoplasma tachyzoite replication, and the concentrations used exhibit no overt toxicity on human host cells. Garcinol also inhibits Plasmodium falciparum asexual replication with a 50% inhibitory concentration (IC50) similar to that for Toxoplasma. Together, these data support that pharmacological inhibition of TgGCN5b leads to a catastrophic failure in gene expression control that prevents parasite replication. PMID:26810649

  9. Diencephalic Size Is Restricted by a Novel Interplay Between GCN5 Acetyltransferase Activity and Retinoic Acid Signaling.

    PubMed

    Wilde, Jonathan J; Siegenthaler, Julie A; Dent, Sharon Y R; Niswander, Lee A

    2017-03-08

    Diencephalic defects underlie an array of neurological diseases. Previous studies have suggested that retinoic acid (RA) signaling is involved in diencephalic development at late stages of embryonic development, but its roles and mechanisms of action during early neural development are still unclear. Here we demonstrate that mice lacking enzymatic activity of the acetyltransferase GCN5 ((Gcn5(hat/hat) )), which were previously characterized with respect to their exencephalic phenotype, exhibit significant diencephalic expansion, decreased diencephalic RA signaling, and increased diencephalic WNT and SHH signaling. Using a variety of molecular biology techniques in both cultured neuroepithelial cells treated with a GCN5 inhibitor and forebrain tissue from (Gcn5(hat/hat) ) embryos, we demonstrate that GCN5, RARα/γ, and the poorly characterized protein TACC1 form a complex in the nucleus that binds specific retinoic acid response elements in the absence of RA. Furthermore, RA triggers GCN5-mediated acetylation of TACC1, which results in dissociation of TACC1 from retinoic acid response elements and leads to transcriptional activation of RA target genes. Intriguingly, RA signaling defects caused by in vitro inhibition of GCN5 can be rescued through RA-dependent mechanisms that require RARβ. Last, we demonstrate that the diencephalic expansion and transcriptional defects seen in (Gcn5(hat/hat) ) mutants can be rescued with gestational RA supplementation, supporting a direct link between GCN5, TACC1, and RA signaling in the developing diencephalon. Together, our studies identify a novel, nonhistone substrate for GCN5 whose modification regulates a previously undescribed, tissue-specific mechanism of RA signaling that is required to restrict diencephalic size during early forebrain development.SIGNIFICANCE STATEMENT Changes in diencephalic size and shape, as well as SNPs associated with retinoic acid (RA) signaling-associated genes, have been linked to neuropsychiatric

  10. Synergistic action of histone acetyltransferase GCN5 and receptor CLAVATA1 negatively affects ethylene responses in Arabidopsis thaliana.

    PubMed

    Poulios, Stylianos; Vlachonasios, Konstantinos E

    2016-02-01

    GENERAL CONTROL NON-REPRESSIBLE 5 (GCN5) is a histone acetyltransferase (HAT) and the catalytic subunit of several multicomponent HAT complexes that acetylate lysine residues of histone H3. Mutants in AtGCN5 display pleiotropic developmental defects including aberrant meristem function. Shoot apical meristem (SAM) maintenance is regulated by CLAVATA1 (CLV1), a receptor kinase that controls the size of the shoot and floral meristems. Upon activation through CLV3 binding, CLV1 signals to the transcription factor WUSCHEL (WUS), restricting WUS expression and thus the meristem size. We hypothesized that GCN5 and CLV1 act together to affect SAM function. Using genetic and molecular approaches, we generated and characterized clv gcn5 mutants. Surprisingly, the clv1-1 gcn5-1 double mutant exhibited constitutive ethylene responses, suggesting that GCN5 and CLV signaling act synergistically to inhibit ethylene responses in Arabidopsis. This genetic and molecular interaction was mediated by ETHYLENE INSENSITIVE 3/ EIN3-LIKE1 (EIN3/EIL1) transcription factors. Our data suggest that signals from the CLV transduction pathway reach the GCN5-containing complexes in the nucleus and alter the histone acetylation status of ethylene-responsive genes, thus translating the CLV information to transcriptional activity and uncovering a link between histone acetylation and SAM maintenance in the complex mode of ethylene signaling.

  11. The oncoprotein HBXIP promotes migration of breast cancer cells via GCN5-mediated microtubule acetylation.

    PubMed

    Li, Leilei; Liu, Bowen; Zhang, Xiaodong; Ye, Lihong

    2015-03-13

    We have documented that the oncoprotein hepatitis B X-interacting protein (HBXIP) is able to promote migration of breast cancer cells. A subset of acetylated microtubules that accumulates in the cell leading edge is necessary for cell polarization and directional migration. In this study, we explored the hypothesis that HBXIP contributes to migration of breast cancer cells by supporting microtubule acetylation in breast cancer cells. We found that HBXIP could induce acetylated microtubules accumulating into the leading protrusion in wound-induced directional migration in breast cancer cells by immunofluorescence staining analysis. Interestingly, HBXIP was able to increase the acetylation of α-tubulin in the cells by immunofluorescence staining and Western blot analysis. Furthermore, we observed that acetyltransferase GCN5 was involved in the event that HBXIP induced increase of acetylated microtubules and their expansion in protrusions in breast cancer cells by Western blot analysis and immunofluorescence staining. Moreover, GCN5 was required for the HBXIP-enhanced migration of breast cancer cells by wound healing assay. Thus, we conclude that HBXIP promotes the migration of breast cancer cells through modulating microtubule acetylation mediated by GCN5. Therapeutically, HBXIP may serve as a novel target in breast cancer.

  12. SAGA complex and Gcn5 are necessary for respiration in budding yeast.

    PubMed

    Canzonetta, Claudia; Leo, Manuela; Guarino, Salvatore Rocco; Montanari, Arianna; Francisci, Silvia; Filetici, Patrizia

    2016-12-01

    In budding yeast, growth through fermentation and/or respiration is dependent on the type of carbon source present in the medium. SAGA complex is the main acetylation complex and is required, together with Rtg factors, for nucleus-mitochondria communication and transcriptional activation of specific nuclear genes. Even though acetylation is necessary for mitochondria activity and respiratory pathways the direct role of histone acetyltransferases and SAGA complex has never been investigated directly. In this study we demonstrate, for the first time, that Gcn5 and SAGA are needed for respiratory metabolism and oxygen consumption. According to a central role for acetylation in respiration we find that the Gcn5 inhibitor CPTH2 had higher efficacy on cells grown in glycerol containing media. We also demonstrated that the opposing activities of Gcn5 and Hda1 modify selectively H3-AcK18 and are essential for respiration. Taken together our results suggest a novel paradigm coupling acetyltransferase activity to respiratory metabolism. Correspondingly we propose the selective utilization of KAT inhibitor CPTH2, combined to the modulation of the respiratory metabolism of the cell, as a promising novel tool of intervention in cancer cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Gcn5 regulates the dissociation of SWI/SNF from chromatin by acetylation of Swi2/Snf2

    PubMed Central

    Kim, Jeong-Hoon; Saraf, Anita; Florens, Laurence; Washburn, Michael; Workman, Jerry L.

    2010-01-01

    The positive link between the SWI/SNF and the Gcn5 histone acetyltransferase in transcriptional activation has been well described. Here we report an inhibitory role for Gcn5 in SWI/SNF targeting. We demonstrate that Gcn5-containing complexes directly acetylate the Snf2 subunit of the SWI/SNF complex in vitro, as well as in vivo. Moreover, the acetylation of Snf2 facilitates the dissociation of the SWI/SNF complex from acetylated histones, and reduces its association with promoters in vivo. These data reveal a novel mechanism by which Gcn5 modulates chromatin structure not only through the acetylation of histones, but also by directly acetylating Snf2. PMID:21159817

  14. Genome-wide cooperation by HAT Gcn5, remodeler SWI/SNF, and chaperone Ydj1 in promoter nucleosome eviction and transcriptional activation

    PubMed Central

    Qiu, Hongfang; Chereji, Răzvan V.; Hu, Cuihua; Cole, Hope A.; Rawal, Yashpal; Clark, David J.; Hinnebusch, Alan G.

    2016-01-01

    Chaperones, nucleosome remodeling complexes, and histone acetyltransferases have been implicated in nucleosome disassembly at promoters of particular yeast genes, but whether these cofactors function ubiquitously, as well as the impact of nucleosome eviction on transcription genome-wide, is poorly understood. We used chromatin immunoprecipitation of histone H3 and RNA polymerase II (Pol II) in mutants lacking single or multiple cofactors to address these issues for about 200 genes belonging to the Gcn4 transcriptome, of which about 70 exhibit marked reductions in H3 promoter occupancy on induction by amino acid starvation. Examining four target genes in a panel of mutants indicated that SWI/SNF, Gcn5, the Hsp70 cochaperone Ydj1, and chromatin-associated factor Yta7 are required downstream from Gcn4 binding, whereas Asf1/Rtt109, Nap1, RSC, and H2AZ are dispensable for robust H3 eviction in otherwise wild-type cells. Using ChIP-seq to interrogate all 70 exemplar genes in single, double, and triple mutants implicated Gcn5, Snf2, and Ydj1 in H3 eviction at most, but not all, Gcn4 target promoters, with Gcn5 generally playing the greatest role and Ydj1 the least. Remarkably, these three cofactors cooperate similarly in H3 eviction at virtually all yeast promoters. Defective H3 eviction in cofactor mutants was coupled with reduced Pol II occupancies for the Gcn4 transcriptome and the most highly expressed uninduced genes, but the relative Pol II levels at most genes were unaffected or even elevated. These findings indicate that nucleosome eviction is crucial for robust transcription of highly expressed genes but that other steps in gene activation are more rate-limiting for most other yeast genes. PMID:26602697

  15. The impact of a 48-h fast on SIRT1 and GCN5 in human skeletal muscle.

    PubMed

    Edgett, Brittany A; Scribbans, Trisha D; Raleigh, James P; Matusiak, Jennifer B L; Boonstra, Kristen; Simpson, Craig A; Perry, Christopher G R; Quadrilatero, Joe; Gurd, Brendon J

    2016-09-01

    The present study examined the impact of a 48 h fast on the expression and activation status of SIRT1 and GCN5, the relationship between SIRT1/GCN5 and the gene expression of PGC-1α, and the PGC-1α target PDK4 in the skeletal muscle of 10 lean healthy men (age, 22.0 ± 1.5 years; peak oxygen uptake, 47.2 ± 6.7 mL/(min·kg)). Muscle biopsies and blood samples were collected 1 h postprandial (Fed) and following 48 h of fasting (Fasted). Plasma insulin (Fed, 80.8 ± 47.9 pmol/L; Fasted, not detected) and glucose (Fed, 4.36 ± 0.86; Fasted, 3.74 ± 0.25 mmol/L, p = 0.08) decreased, confirming participant adherence to fasting. Gene expression of PGC-1α decreased (p < 0.05, -24%), while SIRT1 and PDK4 increased (p < 0.05, +11% and +1023%, respectively), and GCN5 remained unchanged. No changes were observed for whole-muscle protein expression of SIRT1, GCN5, PGC-1α, or COX IV. Phosphorylation of SIRT1, AMPKα, ACC, p38 MAPK, and PKA substrates as well as nuclear acetylation status was also unaltered. Additionally, nuclear SIRT1 activity, GCN5, and PGC-1α content remained unchanged. Preliminary findings derived from regression analysis demonstrate that changes in nuclear GCN5 and SIRT1 activity/phosphorylation may contribute to the control of PGC-1α, but not PDK4, messenger RNA expression following fasting. Collectively, and in contrast with previous animal studies, our data are inconsistent with the altered activation status of SIRT1 and GCN5 in response to 48 h of fasting in human skeletal muscle.

  16. Mutagenesis of tGCN5 core region reveals two critical surface residues F90 and R140

    SciTech Connect

    Mehta, Kinjal Rajesh; Chan, Yan M.; Lee, Man X.; Yang, Ching Yao; Voloshchuk, Natalya; Montclare, Jin Kim

    2010-09-24

    Research highlights: {yields} Mutagenesis of the tGCN5 core region reveals two residues important for function. {yields} Developed a fluorescent lysate-based activity assay to assess mutants. {yields} Surface-exposed residues F90 and R140 of tGCN5 are critical for H3 acetylation. -- Abstract: Tetrahymena General Control Non-Derepressor 5 (tGCN5) is a critical regulator of gene transcription via acetylation of histones. Since the acetylation ability has been attributed to the 'core region', we perform mutagenesis of residues within the tGCN5 'core region' in order to identify those critical for function and stability. Residues that do not participate in catalysis are identified, mutated and characterized for activity, structure and thermodynamic stability. Variants I107V, Q114L, A121T and A130S maintain the acetylation function relative to wild-type tGCN5, while variants F90Y, F112R and R140H completely abolish function. Of the three non-functional variants, since F112 is mutated into a non-homologous charged residue, a loss in function is expected. However, the remaining two variants are mutated into homologous residues, suggesting that F90 and R140 are critical for the activity of tGCN5. While mutation to homologous residue maintains acetylation of histone H3 for the majority of the variants, the two surface-exposed residues, F90 and R140, appear to be essential for tGCN5 function, structure or stability.

  17. Glucocorticoid-stimulated preadipocyte differentiation is mediated through acetylation of C/EBPbeta by GCN5.

    PubMed

    Wiper-Bergeron, Nadine; Salem, Houssein Abdou; Tomlinson, Julianna J; Wu, Dongmei; Haché, Robert J G

    2007-02-20

    Preadipocyte differentiation in culture is driven by an insulin and cAMP dependant transcriptional cascade which induces the bzip transcription factors C/EBPbeta and C/EBPdelta. We have previously shown that glucocorticoid treatment, which strongly potentiates this differentiation pathway, stimulates the titration of the corepressor histone deacetylase 1 (HDAC1) from C/EBPbeta. This results in a dramatic enhancement of C/EBPbeta-dependent transcription from the C/EBPalpha promoter, concomitant with potentiation of preadipocyte differentiation. Here, we show that C/EBPbeta is acetylated by GCN5 and PCAF within a cluster of lysine residues between amino acids 98-102 and that this acetylation is strongly induced by glucocorticoid treatment. Arginine substitution of the lysine residues within the acetylation motif of C/EBPbeta prevented acetylation and blocked the ability of glucocorticoids to enhance C/EBPbeta-directed transcription and to potentiate C/EBPbeta-dependent preadipocyte differentiation. Moreover, acetylation of C/EBPbeta appeared to directly interfere with the interaction of HDAC1 with C/EBPbeta, suggesting that PCAF/GCN5-dependent acetylation of C/EBPbeta serves as an important molecular switch in determining the transcriptional regulatory potential of this transcription factor.

  18. Autoregulation of the Rsc4 Tandem Bromodomain by Gcn5 Acetylation

    SciTech Connect

    VanDemark,A.; Kasten, M.; Ferris, E.; Heroux, A.; Hill, C.; Cairns, B.

    2007-01-01

    An important issue for chromatin remodeling complexes is how their bromodomains recognize particular acetylated lysine residues in histones. The Rsc4 subunit of the yeast remodeler RSC contains an essential tandem bromodomain (TBD) that binds acetylated K14 of histone H3 (H3K14ac). We report a series of crystal structures that reveal a compact TBD that binds H3K14ac in the second bromodomain and, remarkably, binds acetylated K25 of Rsc4 itself in the first bromodomain. Endogenous Rsc4 is acetylated only at K25, and Gcn5 is identified as necessary and sufficient for Rsc4 K25 acetylation in vivo and in vitro. Rsc4 K25 acetylation inhibits binding to H3K14ac, and mutation of Rsc4 K25 results in altered growth rates. These data suggest an autoregulatory mechanism in which Gcn5 performs both the activating (H3K14ac) and inhibitory (Rsc4 K25ac) modifications, perhaps to provide temporal regulation. Additional regulatory mechanisms are indicated as H3S10 phosphorylation inhibits Rsc4 binding to H3K14ac peptides.

  19. Expression of PCAF, p300 and Gcn5 and more highly acetylated histone H4 in pediatric tumors.

    PubMed

    Armas-Pineda, C; Arenas-Huertero, F; Pérezpeñia-Diazconti, M; Chico-Ponce de León, F; Sosa-Sáinz, G; Lezama, P; Recillas-Targa, F

    2007-06-01

    Any deregulation of histone acetyltransferases (HATs) could affect several processes in tumors. In this paper, the expression of the PCAF, p300 and Gcn5 HATs by RT-PCR in 34 tumor samples was evaluated. Samples of both central nervous system tumors (CNST, 13 cases) and Wilm's tumors (WT, 11 cases) over-expressed PCAF up to 1.6-, and Gcn5 up to 1.3-fold, respectively. In 9 out of 10 samples of benign tumors (BT), PCAF was not expressed. The p300 gene was the least expressed in all tumors. The medians of expression of PCAF (124.0 DU) and Gcn5 (127.0 DU) genes were higher in CNST than in both WT (102.0 and 101.0 DU, respectively) and BT (70.0 and 82.4 DU, respectively). There was a trend to decrease the expression of PCAF and Gcn5 genes in CNST, according to: chemotherapy (110.0 and 96.0 DU, respectively), chemo plus radiotherapy (124.0 and 115.0 DU, respectively) or no treatment (134.0 and 142.0 DU, respectively) in the tumors. A similar trend was observed in WT. Finally, we revealed more highly acetylated forms of histone H4 in CNST and WT. The over-expression of PCAF could represent a new molecular tumor marker in malignant tumors, especially in CNST in pediatric patients.

  20. GCN5L1 modulates cross-talk between mitochondria and cell signaling to regulate FoxO1 stability and gluconeogenesis.

    PubMed

    Wang, Lingdi; Scott, Iain; Zhu, Lu; Wu, Kaiyuan; Han, Kim; Chen, Yong; Gucek, Marjan; Sack, Michael N

    2017-09-12

    The mitochondrial enriched GCN5-like 1 (GCN5L1) protein has been shown to modulate mitochondrial protein acetylation, mitochondrial content and mitochondrial retrograde signaling. Here we show that hepatic GCN5L1 ablation reduces fasting glucose levels and blunts hepatic gluconeogenesis without affecting systemic glucose tolerance. PEPCK and G6Pase transcript levels are downregulated in hepatocytes from GCN5L1 liver specific knockout mice and their upstream regulator, FoxO1 protein levels are decreased via proteasome-dependent degradation and via reactive oxygen species mediated ERK-1/2 phosphorylation. ERK inhibition restores FoxO1, gluconeogenic enzyme expression and glucose production. Reconstitution of mitochondrial-targeted GCN5L1 blunts mitochondrial ROS, ERK activation and increases FoxO1, gluconeogenic enzyme expression and hepatocyte glucose production. We suggest that mitochondrial GCN5L1 modulates post-translational control of FoxO1, regulates gluconeogenesis and controls metabolic pathways via mitochondrial ROS mediated ERK activation. Exploring mechanisms underpinning GCN5L1 mediated ROS signaling may expand our understanding of the role of mitochondria in gluconeogenesis control.Hepatic gluconeogenesis is tightly regulated at transcriptional level and is essential for survival during prolonged fasting. Here Wang et al. show that the mitochondrial enriched GCN5-like 1 protein controls hepatic glucose production by regulating FoxO1 protein levels via proteasome-dependent degradation and, in turn, gluconeogenic gene expression.

  1. Repression of GCN5 Histone Acetyltransferase Activity via Bromodomain-Mediated Binding and Phosphorylation by the Ku–DNA-Dependent Protein Kinase Complex

    PubMed Central

    Barlev, Nickolai A.; Poltoratsky, Vladimir; Owen-Hughes, Tom; Ying, Carol; Liu, Lin; Workman, Jerry L.; Berger, Shelley L.

    1998-01-01

    GCN5, a putative transcriptional adapter in humans and yeast, possesses histone acetyltransferase (HAT) activity which has been linked to GCN5’s role in transcriptional activation in yeast. In this report, we demonstrate a functional interaction between human GCN5 (hGCN5) and the DNA-dependent protein kinase (DNA-PK) holoenzyme. Yeast two-hybrid screening detected an interaction between the bromodomain of hGCN5 and the p70 subunit of the human Ku heterodimer (p70-p80), which is the DNA-binding component of DNA-PK. Interaction between intact hGCN5 and Ku70 was shown biochemically using recombinant proteins and by coimmunoprecipitation of endogenous proteins following chromatography of HeLa nuclear extracts. We demonstrate that the catalytic subunit of DNA-PK phosphorylates hGCN5 both in vivo and in vitro and, moreover, that the phosphorylation inhibits the HAT activity of hGCN5. These findings suggest a possible regulatory mechanism of HAT activity. PMID:9488450

  2. Two different Drosophila ADA2 homologues are present in distinct GCN5 histone acetyltransferase-containing complexes.

    PubMed

    Muratoglu, Selen; Georgieva, Sofia; Pápai, Gábor; Scheer, Elisabeth; Enünlü, Izzet; Komonyi, Orbán; Cserpán, Imre; Lebedeva, Lubov; Nabirochkina, Elena; Udvardy, Andor; Tora, László; Boros, Imre

    2003-01-01

    We have isolated a novel Drosophila (d) gene coding for two distinct proteins via alternative splicing: a homologue of the yeast adaptor protein ADA2, dADA2a, and a subunit of RNA polymerase II (Pol II), dRPB4. Moreover, we have identified another gene in the Drosophila genome encoding a second ADA2 homologue (dADA2b). The two dADA2 homologues, as well as many putative ADA2 homologues from different species, all contain, in addition to the ZZ and SANT domains, several evolutionarily conserved domains. The dada2a/rpb4 and dada2b genes are differentially expressed at various stages of Drosophila development. Both dADA2a and dADA2b interacted with the GCN5 histone acetyltransferase (HAT) in a yeast two-hybrid assay, and dADA2b, but not dADA2a, also interacted with Drosophila ADA3. Both dADA2s further potentiate transcriptional activation in insect and mammalian cells. Antibodies raised either against dADA2a or dADA2b both immunoprecipitated GCN5 as well as several Drosophila TATA binding protein-associated factors (TAFs). Moreover, following glycerol gradient sedimentation or chromatographic purification combined with gel filtration of Drosophila nuclear extracts, dADA2a and dGCN5 were detected in fractions with an apparent molecular mass of about 0.8 MDa whereas dADA2b was found in fractions corresponding to masses of at least 2 MDa, together with GCN5 and several Drosophila TAFs. Furthermore, in vivo the two dADA2 proteins showed different localizations on polytene X chromosomes. These results, taken together, suggest that the two Drosophila ADA2 homologues are present in distinct GCN5-containing HAT complexes.

  3. Two Different Drosophila ADA2 Homologues Are Present in Distinct GCN5 Histone Acetyltransferase-Containing Complexes

    PubMed Central

    Muratoglu, Selen; Georgieva, Sofia; Pápai, Gábor; Scheer, Elisabeth; Enünlü, Izzet; Komonyi, Orbán; Cserpán, Imre; Lebedeva, Lubov; Nabirochkina, Elena; Udvardy, Andor; Tora, László; Boros, Imre

    2003-01-01

    We have isolated a novel Drosophila (d) gene coding for two distinct proteins via alternative splicing: a homologue of the yeast adaptor protein ADA2, dADA2a, and a subunit of RNA polymerase II (Pol II), dRPB4. Moreover, we have identified another gene in the Drosophila genome encoding a second ADA2 homologue (dADA2b). The two dADA2 homologues, as well as many putative ADA2 homologues from different species, all contain, in addition to the ZZ and SANT domains, several evolutionarily conserved domains. The dada2a/rpb4 and dada2b genes are differentially expressed at various stages of Drosophila development. Both dADA2a and dADA2b interacted with the GCN5 histone acetyltransferase (HAT) in a yeast two-hybrid assay, and dADA2b, but not dADA2a, also interacted with Drosophila ADA3. Both dADA2s further potentiate transcriptional activation in insect and mammalian cells. Antibodies raised either against dADA2a or dADA2b both immunoprecipitated GCN5 as well as several Drosophila TATA binding protein-associated factors (TAFs). Moreover, following glycerol gradient sedimentation or chromatographic purification combined with gel filtration of Drosophila nuclear extracts, dADA2a and dGCN5 were detected in fractions with an apparent molecular mass of about 0.8 MDa whereas dADA2b was found in fractions corresponding to masses of at least 2 MDa, together with GCN5 and several Drosophila TAFs. Furthermore, in vivo the two dADA2 proteins showed different localizations on polytene X chromosomes. These results, taken together, suggest that the two Drosophila ADA2 homologues are present in distinct GCN5-containing HAT complexes. PMID:12482983

  4. Spt-Ada-Gcn5-Acetyltransferase (SAGA) Complex in Plants: Genome Wide Identification, Evolutionary Conservation and Functional Determination

    PubMed Central

    Srivastava, Rakesh; Rai, Krishan Mohan; Pandey, Bindu; Singh, Sudhir P.; Sawant, Samir V.

    2015-01-01

    The recruitment of RNA polymerase II on a promoter is assisted by the assembly of basal transcriptional machinery in eukaryotes. The Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex plays an important role in transcription regulation in eukaryotes. However, even in the advent of genome sequencing of various plants, SAGA complex has been poorly defined for their components and roles in plant development and physiological functions. Computational analysis of Arabidopsis thaliana and Oryza sativa genomes for SAGA complex resulted in the identification of 17 to 18 potential candidates for SAGA subunits. We have further classified the SAGA complex based on the conserved domains. Phylogenetic analysis revealed that the SAGA complex proteins are evolutionary conserved between plants, yeast and mammals. Functional annotation showed that they participate not only in chromatin remodeling and gene regulation, but also in different biological processes, which could be indirect and possibly mediated via the regulation of gene expression. The in silico expression analysis of the SAGA components in Arabidopsis and O. sativa clearly indicates that its components have a distinct expression profile at different developmental stages. The co-expression analysis of the SAGA components suggests that many of these subunits co-express at different developmental stages, during hormonal interaction and in response to stress conditions. Quantitative real-time PCR analysis of SAGA component genes further confirmed their expression in different plant tissues and stresses. The expression of representative salt, heat and light inducible genes were affected in mutant lines of SAGA subunits in Arabidopsis. Altogether, the present study reveals expedient evidences of involvement of the SAGA complex in plant gene regulation and stress responses. PMID:26263547

  5. Spt-Ada-Gcn5-Acetyltransferase (SAGA) Complex in Plants: Genome Wide Identification, Evolutionary Conservation and Functional Determination.

    PubMed

    Srivastava, Rakesh; Rai, Krishan Mohan; Pandey, Bindu; Singh, Sudhir P; Sawant, Samir V

    2015-01-01

    The recruitment of RNA polymerase II on a promoter is assisted by the assembly of basal transcriptional machinery in eukaryotes. The Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex plays an important role in transcription regulation in eukaryotes. However, even in the advent of genome sequencing of various plants, SAGA complex has been poorly defined for their components and roles in plant development and physiological functions. Computational analysis of Arabidopsis thaliana and Oryza sativa genomes for SAGA complex resulted in the identification of 17 to 18 potential candidates for SAGA subunits. We have further classified the SAGA complex based on the conserved domains. Phylogenetic analysis revealed that the SAGA complex proteins are evolutionary conserved between plants, yeast and mammals. Functional annotation showed that they participate not only in chromatin remodeling and gene regulation, but also in different biological processes, which could be indirect and possibly mediated via the regulation of gene expression. The in silico expression analysis of the SAGA components in Arabidopsis and O. sativa clearly indicates that its components have a distinct expression profile at different developmental stages. The co-expression analysis of the SAGA components suggests that many of these subunits co-express at different developmental stages, during hormonal interaction and in response to stress conditions. Quantitative real-time PCR analysis of SAGA component genes further confirmed their expression in different plant tissues and stresses. The expression of representative salt, heat and light inducible genes were affected in mutant lines of SAGA subunits in Arabidopsis. Altogether, the present study reveals expedient evidences of involvement of the SAGA complex in plant gene regulation and stress responses.

  6. KNOCKDOWN OF GCN5 HISTONE ACETYLTRANSFERASE by siRNA DECREASES ETHANOL INDUCED HISTONE ACETYLATION AND AFFECTS DIFFERENTIAL EXPRESSION OF GENES IN HUMAN HEPATOMA CELLS

    PubMed Central

    Choudhury, Mahua; Pandey, Ravi S.; Clemens, Dahn L.; Davis, J. Wade; Lim, Robert W.; Shukla, Shivendra D.

    2011-01-01

    We have investigated whether Gcn5, a histone acetyltransferase (HAT), is involved in ethanol induced acetylation of histone H3 at lysine 9 (H3AcK9) and has any effect on the gene expression. Human hepatoma HepG2 cells transfected with ethanol metabolizing enzyme alcohol dehydrogenase 1 (VA 13 cells) were used. Knockdown of Gcn5 by siRNA silencing decreased mRNA and protein levels of GCN5, HAT activity, and also attenuated ethanol induced H3AcK9 in VA13 cells. Illumina gene microarray analysis using total RNA showed 940 transcripts affected by GCN5 silencing or ethanol. Silencing caused differential expression of 891 transcripts (≥ 1.5 fold up- or down- regulated). Among these, 492 transcripts were up- and 399 were down- regulated compared to their respective controls. Using a more stringent threshold (≥ 2.5 fold) the array data from GCN5 silenced samples showed 57 genes differentially expressed (39 up-regulated and 18 down-regulated). Likewise, ethanol caused differential regulation of 57 transcripts with ≥ 1.5 fold change (35 gene up-regulated and 22 down-regulated). Further analysis showed that eight genes were differentially regulated that were common for both ethanol treatment and GCN5 silencing. Among these, SLC44A2 (a putative choline transporter) was strikingly up-regulated by ethanol (3 fold), and GCN5 silencing down regulated it (1.5 fold). The quantitative RT-PCR profile corroborated the array findings. This report demonstrates for the first time that (a) GCN5 differentially affects expression of multiple genes, (b) ethanol induced histone H3-lysine 9 acetylation is mediated via GCN5 and (c) that GCN5 is involved in ethanol induced expression of the putative choline transporter SLC44A2. PMID:21367571

  7. Structure and Functional Diversity of GCN5-Related N-Acetyltransferases (GNAT)

    PubMed Central

    Salah Ud-Din, Abu Iftiaf Md; Tikhomirova, Alexandra; Roujeinikova, Anna

    2016-01-01

    General control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) catalyze the transfer of an acyl moiety from acyl coenzyme A (acyl-CoA) to a diverse group of substrates and are widely distributed in all domains of life. This review of the currently available data acquired on GNAT enzymes by a combination of structural, mutagenesis and kinetic methods summarizes the key similarities and differences between several distinctly different families within the GNAT superfamily, with an emphasis on the mechanistic insights obtained from the analysis of the complexes with substrates or inhibitors. It discusses the structural basis for the common acetyltransferase mechanism, outlines the factors important for the substrate recognition, and describes the mechanism of action of inhibitors of these enzymes. It is anticipated that understanding of the structural basis behind the reaction and substrate specificity of the enzymes from this superfamily can be exploited in the development of novel therapeutics to treat human diseases and combat emerging multidrug-resistant microbial infections. PMID:27367672

  8. Conformational flexibility and subunit arrangement of the modular yeast Spt-Ada-Gcn5 acetyltransferase complex.

    PubMed

    Setiaputra, Dheva; Ross, James D; Lu, Shan; Cheng, Derrick T; Dong, Meng-Qiu; Yip, Calvin K

    2015-04-17

    The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is a highly conserved, 19-subunit histone acetyltransferase complex that activates transcription through acetylation and deubiquitination of nucleosomal histones in Saccharomyces cerevisiae. Because SAGA has been shown to display conformational variability, we applied gradient fixation to stabilize purified SAGA and systematically analyzed this flexibility using single-particle EM. Our two- and three-dimensional studies show that SAGA adopts three major conformations, and mutations of specific subunits affect the distribution among these. We also located the four functional modules of SAGA using electron microscopy-based labeling and transcriptional activator binding analyses and show that the acetyltransferase module is localized in the most mobile region of the complex. We further comprehensively mapped the subunit interconnectivity of SAGA using cross-linking mass spectrometry, revealing that the Spt and Taf subunits form the structural core of the complex. These results provide the necessary restraints for us to generate a model of the spatial arrangement of all SAGA subunits. According to this model, the chromatin-binding domains of SAGA are all clustered in one face of the complex that is highly flexible. Our results relate information of overall SAGA structure with detailed subunit level interactions, improving our understanding of its architecture and flexibility.

  9. Acetylation of mitochondrial proteins by GCN5L1 promotes enhanced fatty acid oxidation in the heart.

    PubMed

    Thapa, Dharendra; Zhang, Manling; Manning, Janet R; Guimarães, Danielle A; Stoner, Michael W; O'Doherty, Robert M; Shiva, Sruti; Scott, Iain

    2017-08-01

    Lysine acetylation is a reversible posttranslational modification and is particularly important in the regulation of mitochondrial metabolic enzymes. Acetylation uses acetyl-CoA derived from fuel metabolism as a cofactor, thereby linking nutrition to metabolic activity. In the present study, we investigated how mitochondrial acetylation status in the heart is controlled by food intake and how these changes affect mitochondrial metabolism. We found that there was a significant increase in cardiac mitochondrial protein acetylation in mice fed a long-term high-fat diet and that this change correlated with an increase in the abundance of the mitochondrial acetyltransferase-related protein GCN5L1. We showed that the acetylation status of several mitochondrial fatty acid oxidation enzymes (long-chain acyl-CoA dehydrogenase, short-chain acyl-CoA dehydrogenase, and hydroxyacyl-CoA dehydrogenase) and a pyruvate oxidation enzyme (pyruvate dehydrogenase) was significantly upregulated in high-fat diet-fed mice and that the increase in long-chain and short-chain acyl-CoA dehydrogenase acetylation correlated with increased enzymatic activity. Finally, we demonstrated that the acetylation of mitochondrial fatty acid oxidation proteins was decreased after GCN5L1 knockdown and that the reduced acetylation led to diminished fatty acid oxidation in cultured H9C2 cells. These data indicate that lysine acetylation promotes fatty acid oxidation in the heart and that this modification is regulated in part by the activity of GCN5L1.NEW & NOTEWORTHY Recent research has shown that acetylation of mitochondrial fatty acid oxidation enzymes has greatly contrasting effects on their activity in different tissues. Here, we provide new evidence that acetylation of cardiac mitochondrial fatty acid oxidation enzymes by GCN5L1 significantly upregulates their activity in diet-induced obese mice. Copyright © 2017 the American Physiological Society.

  10. Histone modifying proteins Gcn5 and Hda1 affect flocculation in Saccharomyces cerevisiae during high-gravity fermentation.

    PubMed

    Dietvorst, Judith; Brandt, Anders

    2010-02-01

    The performance of yeast is often limited by the constantly changing environmental conditions present during high-gravity fermentation. Poor yeast performance contributes to incomplete and slow utilization of the main fermentable sugars which can lead to flavour problems in beer production. The expression of the FLO and MAL genes, which are important for the performance of yeast during industrial fermentations, is affected by complex proteins associated with Set1 (COMPASS) resulting in the induction of flocculation and improved maltose fermentation capacity during the early stages of high-gravity fermentation. In this study, we investigated a possible role for other histone modifying proteins. To this end, we tested a number of histone deacetylases (HDACs) and histone acetyltransferases and we report that flocculation is induced in absence of the histone deacetylase Hda1 or the histone acetyltransferase Gcn5 during high-gravity fermentation. The absence of Gcn5 protein also improved utilization of high concentrations of maltose. Deletion of SIR2 encoding the HDA of the silent informator regulator complex, did not affect flocculation under high-gravity fermentation conditions. Despite the obvious roles for Hda1 and Gcn5 in flocculation, this work indicates that COMPASS mediated silencing is the most important amongst the histone modifying components to control the expression of the FLO genes during high-gravity fermentation.

  11. Interplay among Gcn5, Sch9 and Mitochondria during Chronological Aging of Wine Yeast Is Dependent on Growth Conditions

    PubMed Central

    Picazo, Cecilia; Orozco, Helena; Matallana, Emilia; Aranda, Agustín

    2015-01-01

    Saccharomyces cerevisiae chronological life span (CLS) is determined by a wide variety of environmental and genetic factors. Nutrient limitation without malnutrition, i.e. dietary restriction, expands CLS through the control of nutrient signaling pathways, of which TOR/Sch9 has proven to be the most relevant, particularly under nitrogen deprivation. The use of prototrophic wine yeast allows a better understanding of the role of nitrogen in longevity in natural and more demanding environments, such as grape juice fermentation. We previously showed that acetyltransferase Gcn5, a member of the SAGA complex, has opposite effects on CLS under laboratory and winemaking conditions, and is detrimental under the latter. Here we demonstrate that integrity of the SAGA complex is necessary for prolonged longevity, as its dismantling by SPT20 deletion causes a drop in CLS under both laboratory and winemaking conditions. The sch9Δ mutant is long-lived in synthetic SC medium, as expected, and the combined deletion of GCN5 partially suppresses this phenotype. However it is short-lived in grape juice, likely due to its low nitrogen/carbon ratio. Therefore, unbalance of nutrients can be more relevant for life span than total amounts of them. Deletion of RTG2, which codes for a protein associated with Gcn5 and is a component of the mitochondrial retrograde signal, and which communicates mitochondrial dysfunction to the nucleus, is detrimental under laboratory, but not under winemaking conditions, where respiration seems not so relevant for longevity. Transcription factor Rgm1 was found to be a novel CLS regulator Sch9-dependently. PMID:25658705

  12. Loss of GCN5 leads to increased neuronal apoptosis by upregulating E2F1- and Egr-1-dependent BH3-only protein Bim

    PubMed Central

    Wu, Yanna; Ma, Shanshan; Xia, Yong; Lu, Yangpeng; Xiao, Shiyin; Cao, Yali; Zhuang, Sidian; Tan, Xiangpeng; Fu, Qiang; Xie, Longchang; Li, Zhiming; Yuan, Zhongmin

    2017-01-01

    Cellular acetylation homeostasis is a kinetic balance precisely controlled by histone acetyl-transferase (HAT) and histone deacetylase (HDAC) activities. The loss of the counterbalancing function of basal HAT activity alters the precious HAT:HDAC balance towards enhanced histone deacetylation, resulting in a loss of acetylation homeostasis, which is closely associated with neuronal apoptosis. However, the critical HAT member whose activity loss contributes to neuronal apoptosis remains to be identified. In this study, we found that inactivation of GCN5 by either pharmacological inhibitors, such as CPTH2 and MB-3, or by inactivation with siRNAs leads to a typical apoptosis in cultured cerebellar granule neurons. Mechanistically, the BH3-only protein Bim is transcriptionally upregulated by activated Egr-1 and E2F1 and mediates apoptosis following GCN5 inhibition. Furthermore, in the activity withdrawal- or glutamate-evoked neuronal apoptosis models, GCN5 loses its activity, in contrast to Bim induction. Adenovirus-mediated overexpression of GCN5 suppresses Bim induction and apoptosis. Interestingly, the loss of GCN5 activity and the induction of Egr-1, E2F1 and Bim are involved in the early brain injury (EBI) following subarachnoid haemorrhage (SAH) in rats. HDAC inhibition not only significantly rescues Bim expression and apoptosis induced by either potassium deprivation or GCN5 inactivation but also ameliorates these events and EBI in SAH rats. Taken together, our results highlight a new mechanism by which the loss of GCN5 activity promotes neuronal apoptosis through the transcriptional upregulation of Bim, which is probably a critical event in triggering neuronal death when cellular acetylation homeostasis is impaired. PMID:28125090

  13. Loss of GCN5 leads to increased neuronal apoptosis by upregulating E2F1- and Egr-1-dependent BH3-only protein Bim.

    PubMed

    Wu, Yanna; Ma, Shanshan; Xia, Yong; Lu, Yangpeng; Xiao, Shiyin; Cao, Yali; Zhuang, Sidian; Tan, Xiangpeng; Fu, Qiang; Xie, Longchang; Li, Zhiming; Yuan, Zhongmin

    2017-01-26

    Cellular acetylation homeostasis is a kinetic balance precisely controlled by histone acetyl-transferase (HAT) and histone deacetylase (HDAC) activities. The loss of the counterbalancing function of basal HAT activity alters the precious HAT:HDAC balance towards enhanced histone deacetylation, resulting in a loss of acetylation homeostasis, which is closely associated with neuronal apoptosis. However, the critical HAT member whose activity loss contributes to neuronal apoptosis remains to be identified. In this study, we found that inactivation of GCN5 by either pharmacological inhibitors, such as CPTH2 and MB-3, or by inactivation with siRNAs leads to a typical apoptosis in cultured cerebellar granule neurons. Mechanistically, the BH3-only protein Bim is transcriptionally upregulated by activated Egr-1 and E2F1 and mediates apoptosis following GCN5 inhibition. Furthermore, in the activity withdrawal- or glutamate-evoked neuronal apoptosis models, GCN5 loses its activity, in contrast to Bim induction. Adenovirus-mediated overexpression of GCN5 suppresses Bim induction and apoptosis. Interestingly, the loss of GCN5 activity and the induction of Egr-1, E2F1 and Bim are involved in the early brain injury (EBI) following subarachnoid haemorrhage (SAH) in rats. HDAC inhibition not only significantly rescues Bim expression and apoptosis induced by either potassium deprivation or GCN5 inactivation but also ameliorates these events and EBI in SAH rats. Taken together, our results highlight a new mechanism by which the loss of GCN5 activity promotes neuronal apoptosis through the transcriptional upregulation of Bim, which is probably a critical event in triggering neuronal death when cellular acetylation homeostasis is impaired.

  14. GCN5 and E2F1 stimulate nucleotide excision repair by promoting H3K9 acetylation at sites of damage

    PubMed Central

    Guo, Ruifeng; Chen, Jie; Mitchell, David L.; Johnson, David G.

    2011-01-01

    Chromatin structure is known to be a barrier to DNA repair and a large number of studies have now identified various factors that modify histones and remodel nucleosomes to facilitate repair. In response to ultraviolet (UV) radiation several histones are acetylated and this enhances the repair of DNA photoproducts by the nucleotide excision repair (NER) pathway. However, the molecular mechanism by which UV radiation induces histone acetylation to allow for efficient NER is not completely understood. We recently discovered that the E2F1 transcription factor accumulates at sites of UV-induced DNA damage and directly stimulates NER through a non-transcriptional mechanism. Here we demonstrate that E2F1 associates with the GCN5 acetyltransferase in response to UV radiation and recruits GCN5 to sites of damage. UV radiation induces the acetylation of histone H3 lysine 9 (H3K9) and this requires both GCN5 and E2F1. Moreover, as previously observed for E2F1, knock down of GCN5 results in impaired recruitment of NER factors to sites of damage and inefficient DNA repair. These findings demonstrate a direct role for GCN5 and E2F1 in NER involving H3K9 acetylation and increased accessibility to the NER machinery. PMID:20972224

  15. N-acetylglucosamine sensing by a GCN5-related N-acetyltransferase induces transcription via chromatin histone acetylation in fungi

    PubMed Central

    Su, Chang; Lu, Yang; Liu, Haoping

    2016-01-01

    N-acetylglucosamine (GlcNAc) exists ubiquitously as a component of the surface on a wide range of cells, from bacteria to humans. Many fungi are able to utilize environmental GlcNAc to support growth and induce cellular development, a property important for their survival in various host niches. However, how the GlcNAc signal is sensed and subsequently transduced is largely unknown. Here, we identify a gene that is essential for GlcNAc signalling (NGS1) in Candida albicans, a commensal and pathogenic yeast of humans. Ngs1 can bind GlcNAc through the N-terminal β-N-acetylglucosaminidase homology domain. This binding activates N-acetyltransferase activity in the C-terminal GCN5-related N-acetyltransferase domain, which is required for GlcNAc-induced promoter histone acetylation and transcription. Ngs1 is targeted to the promoters of GlcNAc-inducible genes constitutively by the transcription factor Rep1. Ngs1 is conserved in diverse fungi that have GlcNAc catabolic genes. Thus, fungi use Ngs1 as a GlcNAc-sensor and transducer for GlcNAc-induced transcription. PMID:27694804

  16. A co-activator of nitrogen-regulated transcription in Saccharomyces cerevisiae.

    PubMed

    Soussi-Boudekou, S; André, B

    1999-02-01

    In Saccharomyces cerevisiae, the transcription factors Gln3p and Nil1p of the GATA family play a determinant role in expression of genes that are subject to nitrogen catabolite repression. Here we report the isolation of a new yeast mutant, gan1-1, exhibiting dramatically decreased NAD-linked glutamate dehydrogenase (NAD-GDH) and glutamine synthetase (GS) activities. The GAN1 gene was cloned and found to encode a 488-amino-acid polypeptide bearing no typical DNA binding domain. Gan1p is required for full expression of GLN1, GDH2 and also other nitrogen utilization genes, including GAP1, PUT4, MEP2 and GDH1. The extent to which Gan1p is required, however, varies according to the gene and to the nitrogen source available. We show that Gan1p is in fact involved in Gln3p- and Nil1p-dependent transcription. In the case of Gln3p-dependent transcription, the degree to which Gan1p is required appears to be gene specific. The contribution of Gan1p to gene expression is also influenced by the nitrogen status of the cell. We found that GAN1 is identical to ADA1, which encodes a component of the ADA/GCN5 co-activator complex. Ada1/Gan1p thus represents the first reported case of an accessory protein (a co-activator) linking the GATA-binding proteins Gln3p and Nil1p, mediating nitrogen-regulated transcription, to the basal transcription machinery.

  17. SWI/SNF recruitment to a DNA double-strand break by the NuA4 and Gcn5 histone acetyltransferases.

    PubMed

    Bennett, Gwendolyn; Peterson, Craig L

    2015-06-01

    The DNA damage response to double-strand breaks (DSBs) is critical for cellular viability. Recent work has shown that a host of chromatin regulators are recruited to a DSB, and that they are important for the DNA damage response. However, the functional relationships between different chromatin regulators at DSBs remain unclear. Here we describe a conserved functional interaction among the chromatin remodeling enzyme, SWI/SNF, the NuA4 and Gcn5 histone acetyltransferases, and phosphorylation of histone H2A.X (γH2AX). Specifically, we find that the NuA4 and Gcn5 enzymes are both required for the robust recruitment of SWI/SNF to a DSB, which in turn promotes the phosphorylation of H2A.X.

  18. The SAGA coactivator complex acts on the whole transcribed genome and is required for RNA polymerase II transcription

    PubMed Central

    Bonnet, Jacques; Wang, Chen-Yi; Baptista, Tiago; Vincent, Stéphane D.; Hsiao, Wei-Chun; Stierle, Matthieu; Kao, Cheng-Fu; Tora, László

    2014-01-01

    The SAGA (Spt–Ada–Gcn5 acetyltransferase) coactivator complex contains distinct chromatin-modifying activities and is recruited by DNA-bound activators to regulate the expression of a subset of genes. Surprisingly, recent studies revealed little overlap between genome-wide SAGA-binding profiles and changes in gene expression upon depletion of subunits of the complex. As indicators of SAGA recruitment on chromatin, we monitored in yeast and human cells the genome-wide distribution of histone H3K9 acetylation and H2B ubiquitination, which are respectively deposited or removed by SAGA. Changes in these modifications after inactivation of the corresponding enzyme revealed that SAGA acetylates the promoters and deubiquitinates the transcribed region of all expressed genes. In agreement with this broad distribution, we show that SAGA plays a critical role for RNA polymerase II recruitment at all expressed genes. In addition, through quantification of newly synthesized RNA, we demonstrated that SAGA inactivation induced a strong decrease of mRNA synthesis at all tested genes. Analysis of the SAGA deubiquitination activity further revealed that SAGA acts on the whole transcribed genome in a very fast manner, indicating a highly dynamic association of the complex with chromatin. Thus, our study uncovers a new function for SAGA as a bone fide cofactor for all RNA polymerase II transcription. PMID:25228644

  19. Broad-substrate screen as a tool to identify substrates for bacterial Gcn5-related N-acetyltransferases with unknown substrate specificity.

    PubMed

    Kuhn, Misty L; Majorek, Karolina A; Minor, Wladek; Anderson, Wayne F

    2013-02-01

    Due to a combination of efforts from individual laboratories and structural genomics centers, there has been a surge in the number of members of the Gcn5-related acetyltransferasesuperfamily that have been structurally determined within the past decade. Although the number of three-dimensional structures is increasing steadily, we know little about the individual functions of these enzymes. Part of the difficulty in assigning functions for members of this superfamily is the lack of information regarding how substrates bind to the active site of the protein. The majority of the structures do not show ligand bound in the active site, and since the substrate-binding domain is not strictly conserved, it is difficult to predict the function based on structure alone. Additionally, the enzymes are capable of acetylating a wide variety of metabolites and many may exhibit promiscuity regarding their ability to acetylate multiple classes of substrates, possibly having multiple functions for the same enzyme. Herein, we present an approach to identify potential substrates for previously uncharacterized members of the Gcn5-related acetyltransferase superfamily using a variety of metabolites including polyamines, amino acids, antibiotics, peptides, vitamins, catecholamines, and other metabolites. We have identified potential substrates for eight bacterial enzymes of this superfamily. This information will be used to further structurally and functionally characterize them.

  20. Arabidopsis thaliana transcriptional co-activators ADA2b and SGF29a are implicated in salt stress responses.

    PubMed

    Kaldis, Athanasios; Tsementzi, Despoina; Tanriverdi, Oznur; Vlachonasios, Konstantinos E

    2011-04-01

    The transcriptional co-activator ADA2b is a component of GCN5-containing complexes in eukaryotes. In Arabidopsis, ada2b mutants result in pleiotropic developmental defects and altered responses to low-temperature stress. SGF29 has recently been identified as another component of GCN5-containing complexes. In the Arabidopsis genome there are two orthologs of yeast SGF29, designated as SGF29a and SGF29b. We hypothesized that, in Arabidopsis, one or both SGF29 proteins may work in concert with ADA2b to regulate genes in response to abiotic stress, and we set out to explore the role of SGF29a and ADA2b in salt stress responses. In root growth and seed germination assays, sgf29a-1 mutants were more resistant to salt stress than their wild-type counterparts, whereas ada2b-1 mutant was hypersensitive. The sgf29a;ada2b double mutant displayed similar phenotypes to ada2b-1 mutant with reduced salt sensitivity. The expression of several abiotic stress-responsive genes was reduced in ada2b-1 mutants after 3 h of salt stress in comparison with sgf29a-1 and wild-type plants. In the sgf29a-1;ada2b-1 double mutant, the salt-induced gene expression was affected similarly to ada2b-1. These results suggest that under salt stress the function of SGF29a was masked by ADA2b and perhaps SGF29a could play an auxiliary role to ADA2b action. In chromatin immunoprecipitation assays, reduced levels of histone H3 and H4 acetylation in the promoter and coding region of COR6.6, RAB18, and RD29b genes were observed in ada2b-1 mutants relative to wild-type plants. In conclusion, ADA2b positively regulates salt-induced gene expression by maintaining the locus-specific acetylation of histones H4 and H3.

  1. Host Cell Factor and an Uncharacterized SANT Domain Protein Are Stable Components of ATAC, a Novel dAda2A/dGcn5-Containing Histone Acetyltransferase Complex in Drosophila

    PubMed Central

    Guelman, Sebastián; Suganuma, Tamaki; Florens, Laurence; Swanson, Selene K.; Kiesecker, Cheri L.; Kusch, Thomas; Anderson, Scott; Yates, John R.; Washburn, Michael P.; Abmayr, Susan M.; Workman, Jerry L.

    2006-01-01

    Gcn5 is a conserved histone acetyltransferase (HAT) found in a number of multisubunit complexes from Saccharomyces cerevisiae, mammals, and flies. We previously identified Drosophila melanogaster homologues of the yeast proteins Ada2, Ada3, Spt3, and Tra1 and showed that they associate with dGcn5 to form at least two distinct HAT complexes. There are two different Ada2 homologues in Drosophila named dAda2A and dAda2B. dAda2B functions within the Drosophila version of the SAGA complex (dSAGA). To gain insight into dAda2A function, we sought to identify novel components of the complex containing this protein, ATAC (Ada two A containing) complex. Affinity purification and mass spectrometry revealed that, in addition to dAda3 and dGcn5, host cell factor (dHCF) and a novel SANT domain protein, named Atac1 (ATAC component 1), copurify with this complex. Coimmunoprecipitation experiments confirmed that these proteins associate with dGcn5 and dAda2A, but not with dSAGA-specific components such as dAda2B and dSpt3. Biochemical fractionation revealed that ATAC has an apparent molecular mass of 700 kDa and contains dAda2A, dGcn5, dAda3, dHCF, and Atac1 as stable subunits. Thus, ATAC represents a novel histone acetyltransferase complex that is distinct from previously purified Gcn5/Pcaf-containing complexes from yeast and mammalian cells. PMID:16428443

  2. Assessment of dual inhibition property of newly discovered inhibitors against PCAF and GCN5 through in silico screening, molecular dynamics simulation and DFT approach.

    PubMed

    Suryanarayanan, Venkatesan; Singh, Sanjeev Kumar

    2015-01-01

    p300/CBP-associated factor (PCAF) is one among the histone acetyltransferase (HAT) family enzymes. It is involved in the regulation of transcription by modifying the chromatin structure indirectly through the acetylation of histones. It has been emerged as a promising drug target for various types of cancer. A four-point pharmacophore with two hydrogen bond acceptor, one aromatic ring and one hydrophobic feature, was generated for six highly active isothiazolone derivatives as PCAF inhibitors in order to elucidate their anticancer activity. The generated pharmacophore was used for screening three different databases such as Maybridge, Life Chemicals and Chembridge databases. The screened compounds were further filtered through docking studies. Then the compounds were further carried for ADME prediction. The best three compounds BTB09406, F1418-0051 and F1880-1727 were docked to GCN5 to explore the dual inhibitory properties. The conformational stability of the protein-ligand complexes were analyzed through molecular dynamics simulation. Three best compounds were finally went through electronic structure analysis using density functional theory (DFT) at B3LYP/6-31**G level to understand their molecular reactivity. The results obtained from this study exploit that the three best compounds (BTB09406, F1418-0051 and F1880-1727) were found to have more potent and dual inhibitory properties.

  3. The TDH-GCN5L1-Fbxo15-KBP axis limits mitochondrial biogenesis in mouse embryonic stem cells.

    PubMed

    Donato, Valerio; Bonora, Massimo; Simoneschi, Daniele; Sartini, Davide; Kudo, Yasusei; Saraf, Anita; Florens, Laurence; Washburn, Michael P; Stadtfeld, Matthias; Pinton, Paolo; Pagano, Michele

    2017-03-20

    Self-renewing naive mouse embryonic stem cells (mESCs) contain few mitochondria, which increase in number and volume at the onset of differentiation. KBP (encoded by Kif1bp) is an interactor of the mitochondrial-associated kinesin Kif1Bα. We found that TDH, responsible for mitochondrial production of acetyl-CoA in mESCs, and the acetyltransferase GCN5L1 cooperate to acetylate Lys501 in KBP, allowing its recognition by and degradation via Fbxo15, an F-box protein transcriptionally controlled by the pluripotency core factors and repressed following differentiation. Defects in KBP degradation in mESCs result in an unscheduled increase in mitochondrial biogenesis, enhanced respiration and ROS production, and inhibition of cell proliferation. Silencing of Kif1Bα reverts the aberrant increase in mitochondria induced by KBP stabilization. Notably, following differentiation, Kif1bp(-/-) mESCs display impaired expansion of the mitochondrial mass and form smaller embryoid bodies. Thus, KBP proteolysis limits the accumulation of mitochondria in mESCs to preserve their optimal fitness, whereas KBP accumulation promotes mitochondrial biogenesis in differentiating cells.

  4. Transcriptional coactivators are not required for herpes simplex virus type 1 immediate-early gene expression in vitro.

    PubMed

    Kutluay, Sebla B; DeVos, Sarah L; Klomp, Jennifer E; Triezenberg, Steven J

    2009-04-01

    Virion protein 16 (VP16) of herpes simplex virus type 1 (HSV-1) is a potent transcriptional activator of viral immediate-early (IE) genes. The VP16 activation domain can recruit various transcriptional coactivators to target gene promoters. However, the role of transcriptional coactivators in HSV-1 IE gene expression during lytic infection had not been fully defined. We showed previously that transcriptional coactivators such as the p300 and CBP histone acetyltransferases and the BRM and Brg-1 chromatin remodeling complexes are recruited to viral IE gene promoters in a manner dependent mostly on the presence of the activation domain of VP16. In this study, we tested the hypothesis that these transcriptional coactivators are required for viral IE gene expression during infection of cultured cells. The disrupted expression of the histone acetyltransferases p300, CBP, PCAF, and GCN5 or the BRM and Brg-1 chromatin remodeling complexes did not diminish IE gene expression. Furthermore, IE gene expression was not impaired in cell lines that lack functional p300, or BRM and Brg-1. We also tested whether these coactivators are required for the VP16-dependent induction of IE gene expression from transcriptionally inactive viral genomes associated with high levels of histones in cultured cells. We found that the disruption of coactivators also did not affect IE gene expression in this context. Thus, we conclude that the transcriptional coactivators that can be recruited by VP16 do not contribute significantly to IE gene expression during lytic infection or the induction of IE gene expression from nucleosomal templates in vitro.

  5. A Nonnatural Transcriptional Coactivator

    NASA Astrophysics Data System (ADS)

    Nyanguile, Origene; Uesugi, Motonari; Austin, David J.; Verdine, Gregory L.

    1997-12-01

    In eukaryotes, sequence-specific DNA-binding proteins activate gene expression by recruiting the transcriptional apparatus and chromatin remodeling proteins to the promoter through protein-protein contacts. In many instances, the connection between DNA-binding proteins and the transcriptional apparatus is established through the intermediacy of adapter proteins known as coactivators. Here we describe synthetic molecules with low molecular weight that act as transcriptional coactivators. We demonstrate that a completely nonnatural activation domain in one such molecule is capable of stimulating transcription in vitro and in vivo. The present strategy provides a means of gaining external control over gene activation through intervention using small molecules.

  6. Play.

    ERIC Educational Resources Information Center

    Rogers, Fred; Sharapan, Hedda

    1993-01-01

    Contends that, in childhood, work and play seem to come together. Says that for young children their play is their work, and the more adults encourage children to play, the more they emphasize important lifelong resource. Examines some uses of children's play, making and building, artwork, dramatic play, monsters and superheroes, gun play, and…

  7. Human ADA3 regulates RARα transcriptional activity through direct contact between LxxLL motifs and the receptor coactivator pocket

    PubMed Central

    Li, Chia-Wei; Ai, Ni; Dinh, Gia Khanh; Welsh, William J.; Chen, J. Don

    2010-01-01

    The alternation/deficiency in activation-3 (ADA3) is an essential component of the human p300/CBP-associated factor (PCAF) and yeast Spt-Ada-Gcn5-acetyltransferase (SAGA) histone acetyltransferase complexes. These complexes facilitate transactivation of target genes by association with transcription factors and modification of local chromatin structure. It is known that the yeast ADA3 is required for nuclear receptor (NR)-mediated transactivation in yeast cells; however, the role of mammalian ADA3 in NR signaling remains elusive. In this study, we have investigated how the human (h) ADA3 regulates retinoic acid receptor (RAR) α-mediated transactivation. We show that hADA3 interacts directly with RARα in a hormone-dependent manner and this interaction contributes to RARα transactivation. Intriguingly, this interaction involves classical LxxLL motifs in hADA3, as demonstrated by both ‘loss’ and ‘gain’ of function mutations, as well as a functional coactivator pocket of the receptor. Additionally, we show that hADA3 associates with RARα target gene promoter in a hormone-dependent manner and ADA3 knockdown impairs RARβ2 expression. Furthermore, a structural model was established to illustrate an interaction network within the ADA3/RARα complex. These results suggest that hADA3 is a bona fide transcriptional coactivator for RARα, acting through a conserved mechanism involving direct contacts between NR boxes and the receptor’s co-activator pocket. PMID:20413580

  8. Play

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    Designing a game with a serious purpose involves considering the worlds of Reality and Meaning yet it is undeniably impossible to create a game without a third world, one that is specifically concerned with what makes a game a game: the play elements. This third world, the world of people like designers and artists, and disciplines as computer science and game design, I call the world of Play and this level is devoted to it. The level starts off with some of the misperceptions people have of play. Unlike some may think, we play all the time, even when we grow old—this was also very noticeable in designing the game Levee Patroller as the team exhibited very playful behavior at many occasions. From there, I go into the aspects that characterize this world. The first concerns the goal of the game. This relates to the objectives people have to achieve within the game. This is constituted by the second aspect: the gameplay. Taking actions and facing challenges is subsequently constituted by a gameworld, which concerns the third aspect. And all of it is not possible without the fourth and final aspect, the type of technology that creates and facilitates the game. The four aspects together make up a “game concept” and from this world such a concept can be judged on the basis of three closely interrelated criteria: engagement, immersion, and fun.

  9. Maintenance of Glucose Homeostasis through Acetylation of the Metabolic Transcriptional Coactivator PGC1-alpha

    DTIC Science & Technology

    2009-02-01

    highlight that PGC-1α chemical acetylation is directly controlled by two enzymes: GCN5 and SIRT1 ; this strengths the possibility to use small...acetylated through GCN5 acetyltransferase activity, however under low nutrient conditions Sirt1 deacetylase will keep PGC-1α de-acetylated in an active form...acetylated by GCN5, we decided to use R13 because it did not respond to low glucose levels or Sirt1 activators. We think that the additional acetylation

  10. Sirtuin 1 (SIRT1) Deacetylase Activity Is Not Required for Mitochondrial Biogenesis or Peroxisome Proliferator-activated Receptor-γ Coactivator-1α (PGC-1α) Deacetylation following Endurance Exercise*

    PubMed Central

    Philp, Andrew; Chen, Ai; Lan, Debin; Meyer, Gretchen A.; Murphy, Anne N.; Knapp, Amy E.; Olfert, I. Mark; McCurdy, Carrie E.; Marcotte, George R.; Hogan, Michael C.; Baar, Keith; Schenk, Simon

    2011-01-01

    The protein deacetylase, sirtuin 1 (SIRT1), is a proposed master regulator of exercise-induced mitochondrial biogenesis in skeletal muscle, primarily via its ability to deacetylate and activate peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). To investigate regulation of mitochondrial biogenesis by SIRT1 in vivo, we generated mice lacking SIRT1 deacetylase activity in skeletal muscle (mKO). We hypothesized that deacetylation of PGC-1α and mitochondrial biogenesis in sedentary mice and after endurance exercise would be impaired in mKO mice. Skeletal muscle contractile characteristics were determined in extensor digitorum longus muscle ex vivo. Mitochondrial biogenesis was assessed after 20 days of voluntary wheel running by measuring electron transport chain protein content, enzyme activity, and mitochondrial DNA expression. PGC-1α expression, nuclear localization, acetylation, and interacting protein association were determined following an acute bout of treadmill exercise (AEX) using co-immunoprecipitation and immunoblotting. Contrary to our hypothesis, skeletal muscle endurance, electron transport chain activity, and voluntary wheel running-induced mitochondrial biogenesis were not impaired in mKO versus wild-type (WT) mice. Moreover, PGC-1α expression, nuclear translocation, activity, and deacetylation after AEX were similar in mKO versus WT mice. Alternatively, we made the novel observation that deacetylation of PGC-1α after AEX occurs in parallel with reduced nuclear abundance of the acetyltransferase, general control of amino-acid synthesis 5 (GCN5), as well as reduced association between GCN5 and nuclear PGC-1α. These findings demonstrate that SIRT1 deacetylase activity is not required for exercise-induced deacetylation of PGC-1α or mitochondrial biogenesis in skeletal muscle and suggest that changes in GCN5 acetyltransferase activity may be an important regulator of PGC-1α activity after exercise. PMID:21757760

  11. The crystal structure of Rv1347c, a putative antibiotic resistance protein from Mycobacterium tuberculosis, reveals a GCN5-related fold and suggests an alternative function in siderophore biosynthesis

    SciTech Connect

    Card, G L; Peterson, N A; Smith, C A; Rupp, B; Schick, B M; Baker, E N

    2005-02-15

    Mycobacterium tuberculosis, the cause of TB, is a devastating human pathogen. The emergence of multi-drug resistance in recent years has prompted a search for new drug targets and for a better understanding of mechanisms of resistance. Here we focus on the gene product of an open reading frame from M. tuberculosis, Rv1347c, which is annotated as a putative aminoglycoside N-acetyltransferase. The Rv1347c protein does not show this activity, however, and we show from its crystal structure, coupled with functional and bioinformatic data, that its most likely role is in the biosynthesis of mycobactin, the M. tuberculosis siderophore. The crystal structure of Rv1347c was determined by MAD phasing from selenomethionine-substituted protein and refined at 2.2 {angstrom} resolution (R = 0.227, R{sub free} = 0.257). The protein is monomeric, with a fold that places it in the GCN5-related N-acetyltransferase (GNAT) family of acyltransferases. Features of the structure are an acylCoA binding site that is shared with other GNAT family members, and an adjacent hydrophobic channel leading to the surface that could accommodate long-chain acyl groups. Modeling the postulated substrate, the N{sup {var_epsilon}}-hydroxylysine side chain of mycobactin, into the acceptor substrate binding groove identifies two residues at the active site, His130 and Asp168, that have putative roles in substrate binding and catalysis.

  12. Novel Coactivators for Androgen Receptor

    DTIC Science & Technology

    2005-04-01

    ARA55, it may be overly simplistic to assume that their actions as O’Malley, B. W. The Angelman syndrome -associated protein, E6-AP, is a coactivator...Induction of senescence-like phenotypes by Beckerle, M. C., and Summers, M. F. Structure of the carboxyl-terminal LIM domain forced expression ofhic-5

  13. Emerging roles of TEAD transcription factors and its coactivators in cancers

    PubMed Central

    Pobbati, Ajaybabu V.; Hong, Wanjin

    2013-01-01

    TEAD proteins are transcription factors that are crucial for development, but also play a role in cancers. Several developmentally and pathologically important genes are upregulated by TEADs. TEADs have a TEA domain that enables them to bind specific DNA elements and a transactivation domain that enables them to interact with coactivators. TEADs on their own are unable to activate transcription and they require the help of coactivators. Several TEAD-interacting coactivators are known and they can be classified into three groups: (1) YAP and its paralog TAZ; (2) Vgll proteins; and (3) p160s. Accordingly, these coactivators also play a role in development and cancers. Recent studies have shown that TEADs and their coactivators aid in the progression of various cancers, including the difficult to treat glioblastoma, liver and ovarian cancers. They facilitate cancer progression through expression of proliferation promoting genes such as c-myc, survivin, Axl, CTGF and Cyr61. There is also a good correlation between high TEAD or its coactivator expression and poor prognosis in various cancers. Given the fact that TEADs and their coactivators need to work together for a functional outcome, disrupting the interaction between them appears to be a viable option for cancer therapy. Structures of TEAD-coactivator complexes have been elucidated and will facilitate drug design and development. PMID:23380592

  14. Emerging roles of TEAD transcription factors and its coactivators in cancers.

    PubMed

    Pobbati, Ajaybabu V; Hong, Wanjin

    2013-05-01

    TEAD proteins are transcription factors that are crucial for development, but also play a role in cancers. Several developmentally and pathologically important genes are upregulated by TEADs. TEADs have a TEA domain that enables them to bind specific DNA elements and a transactivation domain that enables them to interact with coactivators. TEADs on their own are unable to activate transcription and they require the help of coactivators. Several TEAD-interacting coactivators are known and they can be classified into three groups: (1) YAP and its paralog TAZ; (2) Vgll proteins; and (3) p160s. Accordingly, these coactivators also play a role in development and cancers. Recent studies have shown that TEADs and their coactivators aid in the progression of various cancers, including the difficult to treat glioblastoma, liver and ovarian cancers. They facilitate cancer progression through expression of proliferation promoting genes such as c-myc, survivin, Axl, CTGF and Cyr61. There is also a good correlation between high TEAD or its coactivator expression and poor prognosis in various cancers. Given the fact that TEADs and their coactivators need to work together for a functional outcome, disrupting the interaction between them appears to be a viable option for cancer therapy. Structures of TEAD-coactivator complexes have been elucidated and will facilitate drug design and development.

  15. Tudor Staphylococcal Nuclease (Tudor-SN), a Novel Regulator Facilitating G1/S Phase Transition, Acting as a Co-activator of E2F-1 in Cell Cycle Regulation*

    PubMed Central

    Su, Chao; Zhang, Chunyan; Tecle, Adiam; Fu, Xue; He, Jinyan; Song, Juan; Zhang, Wei; Sun, Xiaoming; Ren, Yuanyuan; Silvennoinen, Olli; Yao, Zhi; Yang, Xi; Wei, Minxin; Yang, Jie

    2015-01-01

    Tudor staphylococcal nuclease (Tudor-SN) is a multifunctional protein implicated in a variety of cellular processes. In the present study, we identified Tudor-SN as a novel regulator in cell cycle. Tudor-SN was abundant in proliferating cells whereas barely expressed in terminally differentiated cells. Functional analysis indicated that ectopic overexpression of Tudor-SN promoted the G1/S transition, whereas knockdown of Tudor-SN caused G1 arrest. Moreover, the live-cell time-lapse experiment demonstrated that the cell cycle of MEF−/− (knock-out of Tudor-SN in mouse embryonic fibroblasts) was prolonged compared with wild-type MEF+/+. We noticed that Tudor-SN was constantly expressed in every cell cycle phase, but was highly phosphorylated in the G1/S border. Further study revealed that Tudor-SN was a potential substrate of Cdk2/4/6, supportively, we found the physical interaction of endogenous Tudor-SN with Cdk4/6 in G1 and the G1/S border, and with Cdk2 in the G1/S border and S phase. In addition, roscovitine (Cdk1/2/5 inhibitor) or CINK4 (Cdk4/6 inhibitor) could inhibit the phosphorylation of Tudor-SN, whereas ectopic overexpression of Cdk2/4/6 increased the Tudor-SN phosphorylation. The underlying molecular mechanisms indicated that Tudor-SN could physically interact with E2F-1 in vivo, and could enhance the physical association of E2F-1 with GCN5 (a cofactor of E2F-1, which possesses histone acetyltransferase activity), and promote the binding ability of E2F-1 to the promoter region of its target genes CYCLIN A and E2F-1, and as a result, facilitate the gene transcriptional activation. Taken together, Tudor-SN is identified as a novel co-activator of E2F-1, which could facilitate E2F-1-mediated gene transcriptional activation of target genes, which play essential roles in G1/S transition. PMID:25627688

  16. Tudor staphylococcal nuclease (Tudor-SN), a novel regulator facilitating G1/S phase transition, acting as a co-activator of E2F-1 in cell cycle regulation.

    PubMed

    Su, Chao; Zhang, Chunyan; Tecle, Adiam; Fu, Xue; He, Jinyan; Song, Juan; Zhang, Wei; Sun, Xiaoming; Ren, Yuanyuan; Silvennoinen, Olli; Yao, Zhi; Yang, Xi; Wei, Minxin; Yang, Jie

    2015-03-13

    Tudor staphylococcal nuclease (Tudor-SN) is a multifunctional protein implicated in a variety of cellular processes. In the present study, we identified Tudor-SN as a novel regulator in cell cycle. Tudor-SN was abundant in proliferating cells whereas barely expressed in terminally differentiated cells. Functional analysis indicated that ectopic overexpression of Tudor-SN promoted the G1/S transition, whereas knockdown of Tudor-SN caused G1 arrest. Moreover, the live-cell time-lapse experiment demonstrated that the cell cycle of MEF(-/-) (knock-out of Tudor-SN in mouse embryonic fibroblasts) was prolonged compared with wild-type MEF(+/+). We noticed that Tudor-SN was constantly expressed in every cell cycle phase, but was highly phosphorylated in the G1/S border. Further study revealed that Tudor-SN was a potential substrate of Cdk2/4/6, supportively, we found the physical interaction of endogenous Tudor-SN with Cdk4/6 in G1 and the G1/S border, and with Cdk2 in the G1/S border and S phase. In addition, roscovitine (Cdk1/2/5 inhibitor) or CINK4 (Cdk4/6 inhibitor) could inhibit the phosphorylation of Tudor-SN, whereas ectopic overexpression of Cdk2/4/6 increased the Tudor-SN phosphorylation. The underlying molecular mechanisms indicated that Tudor-SN could physically interact with E2F-1 in vivo, and could enhance the physical association of E2F-1 with GCN5 (a cofactor of E2F-1, which possesses histone acetyltransferase activity), and promote the binding ability of E2F-1 to the promoter region of its target genes CYCLIN A and E2F-1, and as a result, facilitate the gene transcriptional activation. Taken together, Tudor-SN is identified as a novel co-activator of E2F-1, which could facilitate E2F-1-mediated gene transcriptional activation of target genes, which play essential roles in G1/S transition. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Maintenance of Glucose Homeostasis through Acetylation of the Metabolic Transcriptional Coactivator PGC-1alpha

    DTIC Science & Technology

    2008-02-01

    GCN5 in cells using adenoviruses that encode both proteins. 12 hours before harvesting, cells were treated with nicotinamide (a SIRT1 deacetylase...Hepatic SIRT1 . Proc. Natl. Acad. Sci. USA. 2007 104(31) 12861-12866. C. Lerin, T.J. Kelly, W. Haas, S.P. Gygi, and P. Puigserver. GCN5-Mediated...Puigserver. Metabolic Adaptations Through PGC-1α and SIRT1 Pathways. FEBS Letters. 582: 46-53. 2008 - University of Utah. Department of

  18. PGC-1 coactivators in cardiac development and disease

    PubMed Central

    Rowe, Glenn C.; Jiang, Aihua; Arany, Zolt

    2010-01-01

    The beating heart requires a constant flux of ATP to maintain contractile function, and there is increasing evidence that energetic defects contribute to the development of heart failure. The last ten years have seen a resurgent interest in cardiac intermediary metabolism, and a dramatic increase in our understanding of transcriptional networks that regulate cardiac energetics. The PPAR-gamma coactivator (PGC)-1 family of proteins plays a central role in these pathways. The mechanisms by which PGC-1 proteins regulate transcriptional networks and are regulated by physiological cues, and the roles they play in cardiac development and disease, are reviewed here. PMID:20884884

  19. Fluorescence anisotropy microplate assay to investigate the interaction of full-length steroid receptor coactivator-1a with steroid receptors

    PubMed Central

    Zhang, Chen; Nordeen, Steven K.; Shapiro, David J.

    2013-01-01

    Estrogens, acting via estrogen receptor (ER) play key roles in growth, differentiation and gene regulation in the reproductive, central nervous and skeletal systems. ER-mediated gene transcription contributes to the development and spread of breast, uterine, and liver cancer. Steroid receptor coactivator-1a (SRC1a) belongs to the P160 family of coactivators, which is the best known of the many coactivators implicated in ER-mediated transactivation. Binding of full-length P160 coactivators to steroid receptors has been difficult to investigate in vitro. This chapter details how to investigate the interaction of SRC1a with ER using the fluorescence anisotropy/polarization microplate assay (FAMA). PMID:23436375

  20. Bimodal Bilinguals Co-activate Both Languages during Spoken Comprehension

    PubMed Central

    Shook, Anthony; Marian, Viorica

    2012-01-01

    Bilinguals have been shown to activate their two languages in parallel, and this process can often be attributed to overlap in input between the two languages. The present study examines whether two languages that do not overlap in input structure, and that have distinct phonological systems, such as American Sign Language (ASL) and English, are also activated in parallel. Hearing ASL-English bimodal bilinguals’ and English monolinguals’ eye-movements were recorded during a visual world paradigm, in which participants were instructed, in English, to select objects from a display. In critical trials, the target item appeared with a competing item that overlapped with the target in ASL phonology. Bimodal bilinguals looked more at competing items than at phonologically unrelated items, and looked more at competing items relative to monolinguals, indicating activation of the sign-language during spoken English comprehension. The findings suggest that language co-activation is not modality specific, and provide insight into the mechanisms that may underlie cross-modal language co-activation in bimodal bilinguals, including the role that top-down and lateral connections between levels of processing may play in language comprehension. PMID:22770677

  1. Molecular cloning and properties of a full-length putative thyroid hormone receptor coactivator.

    PubMed

    Takeshita, A; Yen, P M; Misiti, S; Cardona, G R; Liu, Y; Chin, W W

    1996-08-01

    Thyroid hormone receptors (TRs) are ligand-dependent transcription factors that regulate target gene transcription. The conserved carboxy-terminal region of the ligand-binding domain (AF-2) has been thought to play a critical role in mediating ligand-dependent transactivation by the interaction with coactivator(s). Using bacterially-expressed TR as a probe, far-Western-based expression cDNA library screening identified cDNAs that encode, in part, the recently reported partial steroid receptor coactivator-1 (SRC-1) sequence. Additional work, including 5' RACE, has characterized a full-length cDNA that encodes a approximately 160 kD protein as a putative thyroid hormone receptor coactivator (F-SRC-1). In vitro binding studies show that F-SRC-1 binds to a variety of nuclear hormone receptors in a ligand-dependent manner, along with TBP and TFIIB, suggesting that F-SRC-1 may play a role as a bridging molecule between nuclear hormone receptors and general transcription factors. Interestingly, AF-2 mutants also retain ligand-dependent interaction with F-SRC-1. Although F-SRC-1 recognizes the ligand-induced conformational changes of nuclear hormone receptors, our observations suggest that F-SRC-1 may bind directly with subregion(s) in nuclear hormone receptors other than the AF-2 region.

  2. The Role of Steroid Receptor Coactivator-1 in Breast Cancer

    DTIC Science & Technology

    2001-06-01

    Tsai, B.W. O’Malley, The Angelman syndrome -associated protein, E6-AP, is a coactivator for the nuclear hormone recep-the profusion of coactivators known...deletion of the SRC-1 gene in our labo- The hormone-dependent recruitment of co-activators by NRs ratory. The SRC-1 null phenotype is characterized by...coactivators, the phenotype of the SRC- SRC-I complex, Cell 97 (1999) 17-27. I mouse being the most obvious testament in this [11] V.V. Ogryzko, R.L

  3. Protein arginine methyltransferase 5 (PRMT5) is a novel coactivator of constitutive androstane receptor (CAR)

    SciTech Connect

    Kanno, Yuichiro Inajima, Jun; Kato, Sayaka; Matsumoto, Maika; Tokumoto, Chikako; Kure, Yuki; Inouye, Yoshio

    2015-03-27

    The constitutive androstane receptor (CAR) plays a key role in the expression of xenobiotic/steroid and drug metabolizing enzymes and their transporters. In this study, we demonstrated that protein arginine methyltransferase 5 (PRMT5) is a novel CAR-interacting protein. Furthermore, the PRMT-dependent induction of a CAR reporter gene, which was independent of methyltransferase activity, was enhanced in the presence of steroid receptor coactivator 1 (SRC1), peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) or DEAD box DNA/RNA helicase DP97. Using tetracycline inducible-hCAR system in HepG2 cells, we showed that knockdown of PRMT5 with small interfering RNA suppressed tetracycline -induced mRNA expression of CYP2B6 but not of CYP2C9 or CYP3A4. PRMT5 enhanced phenobarbital-mediated transactivation of a phenobarbital-responsive enhancer module (PBREM)-driven reporter gene in co-operation with PGC-1α in rat primary hepatocytes. Based on these findings, we suggest PRMT5 to be a gene (or promoter)-selective coactivator of CAR by mediating the formation of complexes between hCAR and appropriate coactivators. - Highlights: • Nuclear receptor CAR interact with PRMT5. • PRMT5 enhances transcriptional activity of CAR. • PRMT5 synergistically enhances transactivity of CAR by the co-expression of SRC-1, DP97 or PGC1α. • PRMT5 is a gene-selective co-activator for hCAR.

  4. Structural and Functional Impacts of ER Coactivator Sequential Recruitment.

    PubMed

    Yi, Ping; Wang, Zhao; Feng, Qin; Chou, Chao-Kai; Pintilie, Grigore D; Shen, Hong; Foulds, Charles E; Fan, Guizhen; Serysheva, Irina; Ludtke, Steven J; Schmid, Michael F; Hung, Mien-Chie; Chiu, Wah; O'Malley, Bert W

    2017-09-07

    Nuclear receptors recruit multiple coactivators sequentially to activate transcription. This "ordered" recruitment allows different coactivator activities to engage the nuclear receptor complex at different steps of transcription. Estrogen receptor (ER) recruits steroid receptor coactivator-3 (SRC-3) primary coactivator and secondary coactivators, p300/CBP and CARM1. CARM1 recruitment lags behind the binding of SRC-3 and p300 to ER. Combining cryo-electron microscopy (cryo-EM) structure analysis and biochemical approaches, we demonstrate that there is a close crosstalk between early- and late-recruited coactivators. The sequential recruitment of CARM1 not only adds a protein arginine methyltransferase activity to the ER-coactivator complex, it also alters the structural organization of the pre-existing ERE/ERα/SRC-3/p300 complex. It induces a p300 conformational change and significantly increases p300 HAT activity on histone H3K18 residues, which, in turn, promotes CARM1 methylation activity on H3R17 residues to enhance transcriptional activity. This study reveals a structural role for a coactivator sequential recruitment and biochemical process in ER-mediated transcription. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. PGC-1 coactivators in the cardiovascular system.

    PubMed

    Patten, Ian S; Arany, Zolt

    2012-02-01

    The beating heart consumes more ATP per weight than any other organ. The machineries required for this are many and complex. Fuel and oxygen must be transported via the vasculature, absorbed by cardiomyocytes, broken down, and regulated to match cellular demands. Much of this occurs in mitochondria, which comprise fully one third of cardiac mass. The PGC-1 proteins are transcriptional coactivators that have emerged as powerful orchestrators of these numerous processes, ensuring their proper coregulation in response to intracellular and extracellular cues. An important role for PGC-1s in cardiac function has been revealed over the past few years, and more recently interest in their role in the vasculature has been burgeoning. We review this literature, focusing on recent developments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. The Wnt signaling pathway in cellular proliferation and differentiation: A tale of two coactivators.

    PubMed

    Teo, Jia-Ling; Kahn, Michael

    2010-09-30

    Wnt signaling pathways play divergent roles during development, normal homeostasis and disease. The responses that result from the activation of the pathway control both proliferation and differentiation. Tight regulation and controlled coordination of the Wnt signaling cascade is required to maintain the balance between proliferation and differentiation. The non-redundant roles of the coactivator proteins CBP and p300, within the context of Wnt signaling are discussed. We highlight their roles as integrators of the various inputs that a cell receives to elicit the correct and coordinated response. We propose that essentially all cellular information - i.e. from other signaling pathways, nutrient levels, etc. - is funneled down into a choice of coactivators usage, either CBP or p300, by their interacting partner beta-catenin (or catenin-like molecules in the absence of beta-catenin) to make the critical decision to either remain quiescent, or once entering cycle to proliferate without differentiation or to initiate the differentiation process.

  7. On play and playing.

    PubMed

    Rudan, Dusko

    2013-12-01

    The paper offers a review of the development of the concept of play and playing. The true beginnings of the development of the theories of play are set as late as in the 19th century. It is difficult to define play as such; it may much more easily be defined through its antipode--work. In the beginning, play used to be connected with education; it was not before Freud's theory of psychoanalysis and Piaget's developmental psychology that the importance of play in a child's development began to be explained in more detail. The paper further tackles the role of play in the adult age. Detailed attention is paid to psychodynamic and psychoanalytic authors, in particular D. W. Winnicott and his understanding of playing in the intermediary (transitional) empirical or experiential space. In other words, playing occupies a space and time of its own. The neuroscientific concept of playing is also tackled, in the connection with development as well.

  8. Transcription coactivators for peroxisome proliferator-activated receptors.

    PubMed

    Yu, Songtao; Reddy, Janardan K

    2007-08-01

    Peroxisome proliferator-activated receptors (PPARs) regulate diverse biological processes such as development, differentiation, neoplastic conversion, inflammation and wound healing in addition to their critical roles in energy (lipid and carbohydrate) metabolism. Unliganded PPARs heterodimerize with retinoid X receptor alpha and repress transcription when bound to DNA by interacting with corepressor molecules. Upon canonical ligand binding, PPARs manifest conformational changes that facilitate the dissociation of corepressor molecules to enable a spatiotemporally orchestrated recruitment (association) of coactivators and coactivator-associated proteins to the liganded receptor. Functional significance for the existence of over 200 nuclear receptor cofactors is not readily evident, but emerging gene knockout mouse models show that some of the coactivators are essential for embryonic growth and survival and for controlling receptor specific target gene expression in a cell specific need based demands. Coactivators contain one or more highly conserved LXXLL amphiphatic alpha-helix motif, called nuclear receptor box, for direct interaction with the activation function 2 (AF-2) regions in nuclear receptors. PPARs interact with large multisubunit coactivator protein complexes, some exhibiting intrinsic histone acetyltransferase or methyltransferase activity, while others functioning as facilitators of ATP-dependent chromatin remodeling or as linkers to the basal transcription machinery. While the dynamic and coordinated changes in nuclear receptor expression and differences in the nature of their key target genes are important, it is becoming increasingly evident that perturbations in the expression of coactivators may affect the function of many nuclear receptors including PPARs. Tissue specific differences in coactivator expression add another dimension to the complexity of gene- and cell-specific transcriptional regulation. Identification of PPAR specific

  9. Exploiting receptor tyrosine kinase co-activation for cancer therapy

    PubMed Central

    Tan, Aik-Choon; Vyse, Simon; Huang, Paul H

    2017-01-01

    Studies over the past decade have shown that Receptor Tyrosine Kinase (RTK) co-activation is prevalent in many cancer types. Compelling data demonstrates that cancers are likely to have evolved RTK co-activation as a generic means for driving tumour growth and providing a buffering system to limit the lethal effects of microenvironmental insults including therapy. In this review, we summarise the general principles of RTK co-activation gleaned from key studies over the last decade. We discuss direct and indirect approaches to exploit RTK co-activation for cancer therapy and describe recent developments in computational approaches to predict kinase co-dependencies by integrating drug screening data and kinase inhibitor selectivity profiles. We offer a perspective on the outstanding questions in the field focusing on the implications of RTK co-activation on tumour heterogeneity and cancer evolution and conclude by surveying emerging computational and experimental approaches that will provide further insights into the biology of RTK co-activation and deliver new developments in effective cancer therapies. PMID:27452454

  10. DIFFERENTIAL REGULATION OF EPIDERMAL FUNCTION BY VDR COACTIVATORS

    PubMed Central

    Bikle, D. D.; Teichert, A.; Arnold, L. A.; Uchida, Y.; Elias, P.M.; Oda, Y.

    2010-01-01

    The transcriptional activity of the vitamin D receptor (VDR) is regulated by a number of coactivator and corepressor complexes, which bind to the VDR in a ligand (1,25(OH)2D3) dependent (coactivators) or inhibited (corepressors) process. In the keratinocyte the major coactivator complexes include the vitamin D interacting protein (DRIP) complex and the steroid receptor coactivator (SRC) complexes. These coactivator complexes are not interchangeable in their regulation of keratinocyte proliferation and differentiation. We found that the DRIP complex is the main complex binding to VDR in the proliferating keratinocyte, whereas SRC2 and 3 and their associated proteins are the major coactivators binding to VDR in the differentiated keratinocyte. Moreover, we have found a specific role for DRIP205 in the regulation of β-catenin pathways regulating keratinocyte proliferation, whereas SRC3 uniquely regulates the ability of 1,25(OH)2D3 to induce more differentiated functions such as lipid synthesis and processing required for permeability barrier formation and the innate immune response triggered by disruption of the barrier. These findings provide a basis by which we can understand how one receptor (VDR) and one ligand (1,25(OH)2D3) can regulate a large number of genes in a sequential and differentiation specific fashion. PMID:20298785

  11. Coactivators p300 and CBP maintain the identity of mouse embryonic stem cells by mediating long-range chromatin structure.

    PubMed

    Fang, Fang; Xu, Yifeng; Chew, Kai-Khen; Chen, Xi; Ng, Huck-Hui; Matsudaira, Paul

    2014-07-01

    Master transcription factors Oct4, Sox2, and Nanog are required to maintain the pluripotency and self-renewal of embryonic stem cells (ESCs) by regulating a specific transcriptional network. A few other transcription factors have been shown to be important in ESCs by interacting with these master transcription factors; however, little is known about the transcriptional mechanisms regulated by coregulators (coactivators and corepressors). In this study, we examined the function of two highly homologous coactivators, p300 and CREB-binding protein (CBP), in ESCs. We find that these two coactivators play redundant roles in maintaining the undifferentiated state of ESCs. They are recruited by Nanog through physical interaction to Nanog binding loci, mediating the formation of long-range chromatin looping structures, which is essential to maintain ESC-specific gene expression. Further functional studies reveal that the p300/CBP binding looping fragments contain enhancer activities, suggesting that the formation of p300/CBP-mediated looping structures may recruit distal enhancers to create a concentration of factors for the transcription activation of genes that are involved in self-renewal and pluripotency. Overall, these results provide a total new insight into the transcriptional regulation mechanism of coactivators p300 and CBP in ESCs, which is important in maintaining self-renewal and pluripotency, by mediating the formation of higher order chromosome structures. © 2014 AlphaMed Press.

  12. Molecular Dynamics of "Fuzzy" Transcriptional Activator-Coactivator Interactions

    PubMed Central

    Scholes, Natalie S.; Weinzierl, Robert O. J.

    2016-01-01

    Transcriptional activation domains (ADs) are generally thought to be intrinsically unstructured, but capable of adopting limited secondary structure upon interaction with a coactivator surface. The indeterminate nature of this interface made it hitherto difficult to study structure/function relationships of such contacts. Here we used atomistic accelerated molecular dynamics (aMD) simulations to study the conformational changes of the GCN4 AD and variants thereof, either free in solution, or bound to the GAL11 coactivator surface. We show that the AD-coactivator interactions are highly dynamic while obeying distinct rules. The data provide insights into the constant and variable aspects of orientation of ADs relative to the coactivator, changes in secondary structure and energetic contributions stabilizing the various conformers at different time points. We also demonstrate that a prediction of α-helical propensity correlates directly with the experimentally measured transactivation potential of a large set of mutagenized ADs. The link between α-helical propensity and the stimulatory activity of ADs has fundamental practical and theoretical implications concerning the recruitment of ADs to coactivators. PMID:27175900

  13. PRIC295, a Nuclear Receptor Coactivator, Identified from PPARα-Interacting Cofactor Complex

    PubMed Central

    Pyper, Sean R.; Viswakarma, Navin; Jia, Yuzhi; Zhu, Yi-Jun; Fondell, Joseph D.; Reddy, Janardan K.

    2010-01-01

    The peroxisome proliferator-activated receptor-α (PPARα) plays a key role in lipid metabolism and energy combustion. Chronic activation of PPARα in rodents leads to the development of hepatocellular carcinomas. The ability of PPARα to induce expression of its target genes depends on Mediator, an evolutionarily conserved complex of cofactors and, in particular, the subunit 1 (Med1) of this complex. Here, we report the identification and characterization of PPARα-interacting cofactor (PRIC)-295 (PRIC295), a novel coactivator protein, and show that it interacts with the Med1 and Med24 subunits of the Mediator complex. PRIC295 contains 10 LXXLL signature motifs that facilitate nuclear receptor binding and interacts with PPARα and five other members of the nuclear receptor superfamily in a ligand-dependent manner. PRIC295 enhances the transactivation function of PPARα, PPARγ, and ERα. These data demonstrate that PRIC295 interacts with nuclear receptors such as PPARα and functions as a transcription coactivator under in vitro conditions and may play an important role in mediating the effects in vivo as a member of the PRIC complex with Med1 and Med24. PMID:20885938

  14. Co-activation Probability Estimation (CoPE): An approach for modeling functional co-activation architecture based on neuroimaging coordinates

    PubMed Central

    Chu, Congying; Fan, Lingzhong; Eickhoff, Claudia R.; Liu, Yong; Yang, Yong; Eickhoff, Simon B.; Jiang, Tianzi

    2016-01-01

    Recent progress in functional neuroimaging has prompted studies of brain activation during various cognitive tasks. Coordinate-based meta-analysis has been utilized to discover the brain regions that are consistently activated across experiments. However, within-experiment co-activation relationships, which can reflect the underlying functional relationships between different brain regions, have not been widely studied. In particular, voxel-wise co-activation, which may be able to provide a detailed configuration of the co-activation network, still needs to be modeled. To estimate the voxel-wise co-activation pattern and deduce the co-activation network, a Co-activation Probability Estimation (CoPE) method was proposed to model within-experiment activations for the purpose of defining the co-activations. A permutation test was adopted as a significance test. Moreover, the co-activations were automatically separated into local and long-range ones, based on distance. The two types of co-activations describe distinct features: the first reflects convergent activations; the second represents co-activations between different brain regions. The validation of CoPE was based on five simulation tests and one real dataset derived from studies of working memory. Both the simulated and the real data demonstrated that CoPE was not only able to find local convergence but also significant long-range co-activation. In particular, CoPE was able to identify a ‘core’ co-activation network in the working memory dataset. As a data-driven method, the CoPE method can be used to mine underlying co-activation relationships across experiments in future studies. PMID:26037052

  15. Antagonist coactivation of trunk stabilizer muscles during Pilates exercises.

    PubMed

    Rossi, Denise Martineli; Morcelli, Mary Hellen; Marques, Nise Ribeiro; Hallal, Camilla Zamfolini; Gonçalves, Mauro; Laroche, Dain P; Navega, Marcelo Tavella

    2014-01-01

    The purpose of this study was to compare the antagonist coactivation of the local and global trunk muscles during mat-based exercises of Skilled Modern Pilates. Twelve women performed five exercises and concurrently, surface EMG from internal oblique (OI), multifidus (MU), rectus abdominis (RA) and iliocostalis lumborum (IL) muscles was recorded bilaterally. The percentage of antagonist coactivation between local (OI/MU) and global muscles (RA/IL) was calculated. Individuals new to the practice of these exercises showed differences in coactivation of the trunk muscles between the exercises and these results were not similar bilaterally. Thus, in clinical practice, the therapist should be aware of factors such as compensation and undesirable rotation movements of the trunk. Moreover, the coactivation of global muscles was higher bilaterally in all exercises analyzed. This suggests that the exercises of Skilled Modern Pilates only should be performed after appropriate learning and correct execution of all principles, mainly the Centering Principle. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. A Coactive Sign System for Children Who Are Dual-Sensory Impaired.

    ERIC Educational Resources Information Center

    Watkins, Susan; Clark, Thomas C.

    1991-01-01

    The SKI*HI Institute (Utah) has developed a system of coactive signing for children who are deaf and blind. The system includes optimized coactive signs that are functional, easy to feel, easy to relate to the referent, and easy to make. It also includes techniques for effective coactive sign use. Videotapes of lessons are described. (Author/DB)

  17. Dopaminergic influences on changes in human tactile acuity induced by tactile coactivation.

    PubMed

    Bliem, Barbara; Frombach, Elke; Ragert, Patrick; Knossalla, Frauke; Woitalla, Dirk; Tegenthoff, Martin; Dinse, Hubert R

    2007-07-01

    As shown in animal experiments, dopaminergic mechanisms participate in N-methyl-D-aspartate (NMDA) receptor-dependent neuroplasticity. Dopamine is thought to play a similar role in humans, where it influences learning and memory. Here, we tested the dopaminergic action on learning in the tactile domain. To induce tactile non-associative learning, we applied a tactile coactivation protocol, which is known to improve tactile two-point discrimination of the stimulated finger. We studied the influence of a single oral dose of levodopa (25, 50, 100, 250 or 350 mg) administered preceding the coactivation protocol on changes in tactile performance in different groups of subjects. In addition, 3 x 100 mg levodopa was administered over a time period of 3 h in another group. Under placebo conditions, tactile two-point discrimination was improved on the coactivated index finger. Similar improvement was found when 25, 50 and 250 mg levodopa was applied. On the contrary, tactile improvement was completely eliminated by 1 x 100 and 3 x 100 mg levodopa. No drug effects were found on the left index finger indicating that the drug had no effect on performance per se. In contrast to previous findings in the motor and speech domain, we found that the administration of levodopa exerts either no or even negative effects on non-associative learning in the human somatosensory system. Whenever levodopa is used in neurorehabilitative context, it has to be kept in mind that beneficial effects in the motor or speech domain cannot be easily generalized to other systems.

  18. Effects of fear of falling on muscular coactivation during walking.

    PubMed

    Nagai, Koutatsu; Yamada, Minoru; Uemura, Kazuki; Tanaka, Buichi; Mori, Shuhei; Yamada, Yosuke; Aoyama, Tomoki; Ichihashi, Noriaki; Tsuboyama, Tadao

    2012-04-01

    Increased fear of falling is associated with greater muscular coactivation during standing postural control. Excessive muscular coactivation reduces the performance of agonist muscles. Although several recent studies have observed increased muscular coactivation during walking in older adults, little is known about the relationship between fear of falling and muscular coactivation during walking. The purpose of this study was to compare muscular coactivation during walking between older adults with fear of falling and older adults without fear of falling. Thirty-eight healthy older adults (82.3 ± 6.8 years) participated in this study. Walking speed and step length were measured. Electromyography (EMG) data were collected from the tibialis anterior and soleus during walking to calculate the co-contraction index (CI). Subjects were divided into those with fear of falling and those without fear of falling, on the basis of a modified Falls Efficacy Scale (FES). Stepwise multiple regression analysis was used, with CI as the dependent variable, and fear of falling, experience of falling (during the past year), walking speed, step length, and age as independent variables. Mean values of CI during walking, walking speed, and step length were 51.9 ± 11.7%, 0.90 ± 0.40 m/s, and 0.43±0.11 m, respectively. Eight subjects (21.1%) had fallen within the past year, and 19 subjects (50.0%) had fear of falling. All subjects without fear of falling had FES scores of 10 (maximum score). Subjects with fear of falling had a median FES score of 17 (interquartile range, 13 to 25). Stepwise multiple regression analysis revealed that fear of falling remained significantly associated with CI (p<0.01): CIs for subjects with fear and those without fear were 59.5 ± 12.2% and 46.7 ± 8.5%, respectively. Individuals with a fear of falling have increased muscular co-activation at the ankle joint during walking, at least in a certain subgroup of older adults. Further research is needed to

  19. Reciprocal roles of DBC1 and SIRT1 in regulating estrogen receptor α activity and co-activator synergy

    PubMed Central

    Ji Yu, Eun; Kim, Seok-Hyung; Heo, Kyu; Ou, Chen-Yin; Kim, Jeong Hoon

    2011-01-01

    Estrogen receptor α (ERα) plays critical roles in development and progression of breast cancer. Because ERα activity is strictly dependent upon the interaction with coregulators, coregulators are also believed to contribute to breast tumorigenesis. Cell Cycle and Apoptosis Regulator 1 (CCAR1) is an important co-activator for estrogen-induced gene expression and estrogen-dependent growth of breast cancer cells. Here, we identified Deleted in Breast Cancer 1 (DBC1) as a CCAR1 binding protein. DBC1 was recently shown to function as a negative regulator of the NAD-dependent protein deacetylase SIRT1. DBC1 associates directly with ERα and cooperates synergistically with CCAR1 to enhance ERα function. DBC1 is required for estrogen-induced expression of a subset of ERα target genes as well as breast cancer cell proliferation and for estrogen-induced recruitment of ERα to the target promoters in a gene-specific manner. The mechanism of DBC1 action involves inhibition of SIRT1 interaction with ERα and of SIRT1-mediated deacetylation of ERα. SIRT1 also represses the co-activator synergy between DBC1 and CCAR1 by binding to DBC1 and disrupting its interaction with CCAR1. Our results indicate that DBC1 and SIRT1 play reciprocal roles as major regulators of ERα activity, by regulating DNA binding by ERα and by regulating co-activator synergy. PMID:21596782

  20. Outdoor Play and Play Equipment.

    ERIC Educational Resources Information Center

    Naylor, Heather

    1985-01-01

    Discusses aspects of the play environment and its effect on children's play behavior. Indoor and outdoor play spaces are considered along with factors affecting the use of outdoor environments for play. Children's preferences for different outdoor play environments and for various play structures are explored. Guides for choosing play equipment…

  1. Outdoor Play and Play Equipment.

    ERIC Educational Resources Information Center

    Naylor, Heather

    1985-01-01

    Discusses aspects of the play environment and its effect on children's play behavior. Indoor and outdoor play spaces are considered along with factors affecting the use of outdoor environments for play. Children's preferences for different outdoor play environments and for various play structures are explored. Guides for choosing play equipment…

  2. Development of Novel Vitamin D Receptor–Coactivator Inhibitors

    PubMed Central

    2014-01-01

    Nuclear receptor coregulators are master regulators of transcription and selectively interact with the vitamin D receptor (VDR) to modulate cell differentiation, cell proliferation, and calcium homeostasis. Herein, we report the syntheses and evaluation of highly potent and selective VDR–coactivator inhibitors based on a recently identified 3-indolylmethanamine scaffold. The most active compound, PS121912, selectively inhibited VDR-mediated transcription among eight other nuclear receptors tested. PS121912 is also selectively disrupting the binding between VDR and the third nuclear receptor interaction domain of the coactivator SRC2. Genetic studies revealed that PS121912 behaves like a VDR antagonist by repressing 1,25-(OH)2D3 activated gene transcription. In addition, PS121912 induced apoptosis in HL-60. PMID:24799995

  3. Transcription Coactivators p300 and CBP Are Necessary for Photoreceptor-Specific Chromatin Organization and Gene Expression

    PubMed Central

    Hennig, Anne K.; Peng, Guang-Hua; Chen, Shiming

    2013-01-01

    Rod and cone photoreceptor neurons in the mammalian retina possess specialized cellular architecture and functional features for converting light to a neuronal signal. Establishing and maintaining these characteristics requires appropriate expression of a specific set of genes, which is tightly regulated by a network of photoreceptor transcription factors centered on the cone-rod homeobox protein CRX. CRX recruits transcription coactivators p300 and CBP to acetylate promoter-bound histones and activate transcription of target genes. To further elucidate the role of these two coactivators, we conditionally knocked out Ep300 and/or CrebBP in differentiating rods or cones, using opsin-driven Cre recombinase. Knockout of either factor alone exerted minimal effects, but loss of both factors severely disrupted target cell morphology and function: the unique nuclear chromatin organization seen in mouse rods was reversed, accompanied by redistribution of nuclear territories associated with repressive and active histone marks. Transcription of many genes including CRX targets was severely impaired, correlating with reduced histone H3/H4 acetylation (the products of p300/CBP) on target gene promoters. Interestingly, the presence of a single wild-type allele of either coactivator prevented many of these defects, with Ep300 more effective than Cbp. These results suggest that p300 and CBP play essential roles in maintaining photoreceptor-specific structure, function and gene expression. PMID:23922782

  4. Promoter-specific co-activation by Drosophila Mastermind

    PubMed Central

    Caudy, Michael A.

    2008-01-01

    Mastermind (Mam) is a co-activator protein of binary complexes consisting of Suppressor of Hairless (Su(H)) and Notch Intracellular Domain (NICD) proteins assembled on cis-regulatory regions of target genes activated by Notch signaling. Current evidence indicates that Mastermind is necessary and sufficient for the formation of a functional Su(H)/NICD/Mam ternary complex on at least one specific architecture of Su(H) binding sites, called the SPS element (Su(H) Paired Sites). However, using transcription assays with a combination of native and synthetic Notch target gene promoters in Drosophila cultured cells, we show here that co-activation of Su(H)/NICD complexes on SPS elements by Mam is promoter-specific. Our novel results suggest this promoter specificity is mediated by additional unknown cis-regulatory elements present in the native promoters that are required for the recruitment of Mam and formation of functional Su(H)/NICD/Mam complexes on SPS elements. Together, the findings in this study suggest Mam is not always necessary and sufficient for co-activation of binary Su(H)/NICD complexes on SPS elements. PMID:18930034

  5. Can co-activation reduce kinematic variability? A simulation study.

    PubMed

    Selen, Luc P J; Beek, Peter J; van Dieën, Jaap H

    2005-11-01

    Impedance modulation has been suggested as a means to suppress the effects of internal 'noise' on movement kinematics. We investigated this hypothesis in a neuro-musculo-skeletal model. A prerequisite is that the muscle model produces realistic force variability. We found that standard Hill-type models do not predict realistic force variability in response to variability in stimulation. In contrast, a combined motor-unit pool model and a pool of parallel Hill-type motor units did produce realistic force variability as a function of target force, largely independent of how the force was transduced to the tendon. To test the main hypothesis, two versions of the latter model were simulated as an antagonistic muscle pair, controlling the position of a frictionless hinge joint, with a distal segment having realistic inertia relative to the muscle strength. Increasing the impedance through co-activation resulted in less kinematic variability, except for the lowest levels of co-activation. Model behavior in this region was affected by the noise amplitude and the inertial properties of the model. Our simulations support the idea that muscular co-activation is in principle an effective strategy to meet accuracy demands.

  6. Defining the Communication between Agonist and Coactivator Binding in the Retinoid X Receptor α Ligand Binding Domain*

    PubMed Central

    Boerma, LeeAnn J.; Xia, Gang; Qui, Cheng; Cox, Bryan D.; Chalmers, Michael J.; Smith, Craig D.; Lobo-Ruppert, Susan; Griffin, Patrick R.; Muccio, Donald D.; Renfrow, Matthew B.

    2014-01-01

    Retinoid X receptors (RXRs) are obligate partners for several other nuclear receptors, and they play a key role in several signaling processes. Despite being a promiscuous heterodimer partner, this nuclear receptor is a target of therapeutic intervention through activation using selective RXR agonists (rexinoids). Agonist binding to RXR initiates a large conformational change in the receptor that allows for coactivator recruitment to its surface and enhanced transcription. Here we reveal the structural and dynamical changes produced when a coactivator peptide binds to the human RXRα ligand binding domain containing two clinically relevant rexinoids, Targretin and 9-cis-UAB30. Our results show that the structural changes are very similar for each rexinoid and similar to those for the pan-agonist 9-cis-retinoic acid. The four structural changes involve key residues on helix 3, helix 4, and helix 11 that move from a solvent-exposed environment to one that interacts extensively with helix 12. Hydrogen-deuterium exchange mass spectrometry reveals that the dynamics of helices 3, 11, and 12 are significantly decreased when the two rexinoids are bound to the receptor. When the pan-agonist 9-cis-retinoic acid is bound to the receptor, only the dynamics of helices 3 and 11 are reduced. The four structural changes are conserved in all x-ray structures of the RXR ligand-binding domain in the presence of agonist and coactivator peptide. They serve as hallmarks for how RXR changes conformation and dynamics in the presence of agonist and coactivator to initiate signaling. PMID:24187139

  7. PGC-1-Related Coactivator, a Novel, Serum-Inducible Coactivator of Nuclear Respiratory Factor 1-Dependent Transcription in Mammalian Cells

    PubMed Central

    Andersson, Ulf; Scarpulla, Richard C.

    2001-01-01

    The thermogenic peroxisome proliferator-activated receptor γ (PPAR-γ) coactivator 1 (PGC-1) has previously been shown to activate mitochondrial biogenesis in part through a direct interaction with nuclear respiratory factor 1 (NRF-1). In order to identify related coactivators that act through NRF-1, we searched the databases for sequences with similarities to PGC-1. Here, we describe the first characterization of a 177-kDa transcriptional coactivator, designated PGC-1-related coactivator (PRC). PRC is ubiquitously expressed in murine and human tissues and cell lines; but unlike PGC-1, PRC was not dramatically up-regulated during thermogenesis in brown fat. However, its expression was down-regulated in quiescent BALB/3T3 cells and was rapidly induced by reintroduction of serum, conditions where PGC-1 was not detected. PRC activated NRF-1-dependent promoters in a manner similar to that observed for PGC-1. Moreover, NRF-1 was immunoprecipitated from cell extracts by antibodies directed against PRC, and both proteins were colocalized to the nucleoplasm by confocal laser scanning microscopy. PRC interacts in vitro with the NRF-1 DNA binding domain through two distinct recognition motifs that are separated by an unstructured proline-rich region. PRC also contains a potent transcriptional activation domain in its amino terminus adjacent to an LXXLL motif. The spatial arrangement of these functional domains coincides with those found in PGC-1, supporting the conclusion that PRC and PGC-1 are structurally and functionally related. We conclude that PRC is a functional relative of PGC-1 that operates through NRF-1 and possibly other activators in response to proliferative signals. PMID:11340167

  8. Steroid receptor coactivator-3 regulates glucose metabolism in bladder cancer cells through coactivation of hypoxia inducible factor 1α.

    PubMed

    Zhao, Wei; Chang, Cunjie; Cui, Yangyan; Zhao, Xiaozhi; Yang, Jun; Shen, Lan; Zhou, Ji; Hou, Zhibo; Zhang, Zhen; Ye, Changxiao; Hasenmayer, Donald; Perkins, Robert; Huang, Xiaojing; Yao, Xin; Yu, Like; Huang, Ruimin; Zhang, Dianzheng; Guo, Hongqian; Yan, Jun

    2014-04-18

    Cancer cell proliferation is a metabolically demanding process, requiring high glycolysis, which is known as "Warburg effect," to support anabolic growth. Steroid receptor coactivator-3 (SRC-3), a steroid receptor coactivator, is overexpressed and/or amplified in multiple cancer types, including non-steroid targeted cancers, such as urinary bladder cancer (UBC). However, whether SRC-3 regulates the metabolic reprogramming for cancer cell growth is unknown. Here, we reported that overexpression of SRC-3 accelerated UBC cell growth, accompanied by the increased expression of genes involved in glycolysis. Knockdown of SRC-3 reduced the UBC cell glycolytic rate under hypoxia, decreased tumor growth in nude mice, with reduction of proliferating cell nuclear antigen and lactate dehydrogenase expression levels. We further revealed that SRC-3 could interact with hypoxia inducible factor 1α (HIF1α), which is a key transcription factor required for glycolysis, and coactivate its transcriptional activity. SRC-3 was recruited to the promoters of HIF1α-target genes, such as glut1 and pgk1. The positive correlation of expression levels between SRC-3 and Glut1 proteins was demonstrated in human UBC patient samples. Inhibition of glycolysis through targeting HK2 or LDHA decelerated SRC-3 overexpression-induced cell growth. In summary, overexpression of SRC-3 promoted glycolysis in bladder cancer cells through HIF1α to facilitate tumorigenesis, which may be an intriguing drug target for bladder cancer therapy.

  9. Playful Gaming.

    ERIC Educational Resources Information Center

    Makedon, Alexander

    A philosophical analysis of play and games is undertaken in this paper. Playful gaming, which is shown to be a synthesis of play and games, is utilized as a category for undertaking the examination of play and games. The significance of playful gaming to education is demonstrated through analyses of Plato's, Dewey's, Sartre's, and Marcuse's…

  10. The role of peroxisome proliferator-activated receptor-coactivator-1 gene in skin aging.

    PubMed

    Aghaei, Shahrzad; Nilforoushzadeh, Mohammad Ali; Aghaei, Maryam

    2016-01-01

    Skin aging is a continuous process that exhibits fine and deep wrinkles, thin and transparent skin, loss of underlying fat, dry skin and itch, following decreased collagen and elastin synthesis. Both extrinsic and intrinsic agents are considered in the pathogenesis on skin aging. Extrinsic factors such as sun exposure, windy and dry weather, nutrition, and lifestyle may induce premature aging, toxic-free radicals, and reactive oxygen species due to decreasing normal function of mitochondria which play the major intrinsic factors in premature skin aging. One of the major genetic factors in mitochondrial function is peroxisome proliferator-activated receptor-coactivator-1 (PGC-1) gene. This factor could delay skin aging by increasing the mitochondrial biogenesis and replication and oxidative phosphorylation and so may induce free radical scavenging. This review is focused on intrinsic skin aging and the role of PGC-1 protein in decreasing effect of aging causes.

  11. The role of peroxisome proliferator-activated receptor-coactivator-1 gene in skin aging

    PubMed Central

    Aghaei, Shahrzad; Nilforoushzadeh, Mohammad Ali; Aghaei, Maryam

    2016-01-01

    Skin aging is a continuous process that exhibits fine and deep wrinkles, thin and transparent skin, loss of underlying fat, dry skin and itch, following decreased collagen and elastin synthesis. Both extrinsic and intrinsic agents are considered in the pathogenesis on skin aging. Extrinsic factors such as sun exposure, windy and dry weather, nutrition, and lifestyle may induce premature aging, toxic-free radicals, and reactive oxygen species due to decreasing normal function of mitochondria which play the major intrinsic factors in premature skin aging. One of the major genetic factors in mitochondrial function is peroxisome proliferator-activated receptor-coactivator-1 (PGC-1) gene. This factor could delay skin aging by increasing the mitochondrial biogenesis and replication and oxidative phosphorylation and so may induce free radical scavenging. This review is focused on intrinsic skin aging and the role of PGC-1 protein in decreasing effect of aging causes. PMID:27904582

  12. CRTC2 Is a Coactivator of GR and Couples GR and CREB in the Regulation of Hepatic Gluconeogenesis

    PubMed Central

    Hill, Micah J.; Suzuki, Shigeru; Segars, James H.

    2016-01-01

    Glucocorticoid hormones play essential roles in the regulation of gluconeogenesis in the liver, an adaptive response that is required for the maintenance of circulating glucose levels during fasting. Glucocorticoids do this by cooperating with glucagon, which is secreted from pancreatic islets to activate the cAMP-signaling pathway in hepatocytes. The cAMP-response element-binding protein (CREB)-regulated transcription coactivator 2 (CRTC2) is a coactivator known to be specific to CREB and plays a central role in the glucagon-mediated activation of gluconeogenesis in the early phase of fasting. We show here that CRTC2 also functions as a coactivator for the glucocorticoid receptor (GR). CRTC2 strongly enhances GR-induced transcriptional activity of glucocorticoid-responsive genes. CRTC2 physically interacts with the ligand-binding domain of the GR through a region spanning amino acids 561–693. Further, CRTC2 is required for the glucocorticoid-associated cooperative mRNA expression of the glucose-6-phosphatase, a rate-limiting enzyme for hepatic gluconeogenesis, by facilitating the attraction of GR and itself to its promoter region already occupied by CREB. CRTC2 is required for the maintenance of blood glucose levels during fasting in mice by enhancing the GR transcriptional activity on both the G6p and phosphoenolpyruvate carboxykinase (Pepck) genes. Finally, CRTC2 modulates the transcriptional activity of the progesterone receptor, indicating that it may influence the transcriptional activity of other steroid/nuclear receptors. Taken together, these results reveal that CRTC2 plays an essential role in the regulation of hepatic gluconeogenesis through coordinated regulation of the glucocorticoid/GR- and glucagon/CREB-signaling pathways on the key genes G6P and PEPCK. PMID:26652733

  13. CRTC2 Is a Coactivator of GR and Couples GR and CREB in the Regulation of Hepatic Gluconeogenesis.

    PubMed

    Hill, Micah J; Suzuki, Shigeru; Segars, James H; Kino, Tomoshige

    2016-01-01

    Glucocorticoid hormones play essential roles in the regulation of gluconeogenesis in the liver, an adaptive response that is required for the maintenance of circulating glucose levels during fasting. Glucocorticoids do this by cooperating with glucagon, which is secreted from pancreatic islets to activate the cAMP-signaling pathway in hepatocytes. The cAMP-response element-binding protein (CREB)-regulated transcription coactivator 2 (CRTC2) is a coactivator known to be specific to CREB and plays a central role in the glucagon-mediated activation of gluconeogenesis in the early phase of fasting. We show here that CRTC2 also functions as a coactivator for the glucocorticoid receptor (GR). CRTC2 strongly enhances GR-induced transcriptional activity of glucocorticoid-responsive genes. CRTC2 physically interacts with the ligand-binding domain of the GR through a region spanning amino acids 561-693. Further, CRTC2 is required for the glucocorticoid-associated cooperative mRNA expression of the glucose-6-phosphatase, a rate-limiting enzyme for hepatic gluconeogenesis, by facilitating the attraction of GR and itself to its promoter region already occupied by CREB. CRTC2 is required for the maintenance of blood glucose levels during fasting in mice by enhancing the GR transcriptional activity on both the G6p and phosphoenolpyruvate carboxykinase (Pepck) genes. Finally, CRTC2 modulates the transcriptional activity of the progesterone receptor, indicating that it may influence the transcriptional activity of other steroid/nuclear receptors. Taken together, these results reveal that CRTC2 plays an essential role in the regulation of hepatic gluconeogenesis through coordinated regulation of the glucocorticoid/GR- and glucagon/CREB-signaling pathways on the key genes G6P and PEPCK.

  14. Coactivator Recruitment of AhR/ARNT1

    PubMed Central

    Endler, Alexander; Chen, Li; Shibasaki, Futoshi

    2014-01-01

    A common feature of nuclear receptors (NRs) is the transformation of external cell signals into specific transcriptions of the signal molecule. Signal molecules function as ligands for NRs and, after their uptake, activated NRs form homo- or heterodimers at promoter recognition sequences of the specific genes in the nucleus. Another common feature of NRs is their dependence on coactivators, which bridge the basic transcriptional machinery and other cofactors to the target genes, in order to initiate transcription and to unwind histone-bound DNA for exposing additional promoter recognition sites via their histone acetyltransferase (HAT) function. In this review, we focus on our recent findings related to the recruitment of steroid receptor coactivator 1 (SRC1/NCoA1) by the estrogen receptor-α (ERα) and by the arylhydrocarbon receptor/arylhydrocarbon receptor nuclear translocator 1 (AhR/ARNT1) complex. We also describe the extension of our previously published findings regarding the binding between ARNT1.1 exon16 and SRC1e exon 21, via in silico analyses of androgen receptor (AR) NH2-carboxyl-terminal interactions, the results of which were verified by in vitro experiments. Based on these data, we suggest a newly derived tentative binding site of nuclear coactivator 2/glucocorticoid receptor interacting protein-1/transcriptional intermediary factor 2 (NCOA-2/ GRIP-1/TIF-2) for ARNT1.1 exon 16. Furthermore, results obtained by immunoprecipitation have revealed a second leucine-rich binding site for hARNT1.1 exon 16 in SRC1e exon 21 (LSSTDLL). Finally, we discuss the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an endocrine disruptor for estrogen related transcription. PMID:24950180

  15. Co-activation based parcellation of the human frontal pole

    PubMed Central

    Ray, KL.; Zald, DH.; Bludau, S.; Riedel, MC.; Bzdok, D.; Yanes, J.; Falcone, KE.; Amunts, K.; Fox, PT.; Eickhoff, SB.; Laird, AR.

    2015-01-01

    Historically, the human frontal pole (FP) has been considered as a single architectonic area. Brodmann’s area 10, in the frontal lobe with known contributions in the execution of various higher order cognitive processes. However, recent cytoarchitectural studies of the FP in humans have shown that this portion of cortex contains two distinct cytoarchitectonic regions. Since architectonic differences are accompanied by differential connectivity and functions, the frontal pole qualifies as a candidate region for exploratory parcellation into functionally discrete subregions. We investigated whether this functional heterogeneity is reflected in distinct segregations within cytoarchitectonically defined FP-areas using meta-analytic co-activation based parcellation (CBP). The CBP method examined the co-activation patterns of all voxels within the FP as reported in functional neuroimaging studies archived in the BrainMap database. Voxels within the FP were subsequently clustered into sub-regions based on the similarity of their respective meta-analytically derived co-activation maps. Performing this CBP analysis on the FP via k-means clustering produced a distinct 3-cluster parcellation for each hemisphere corresponding to previously identified cytoarchitectural differences. Post-hoc functional characterization of clusters via BrainMap metadata revealed that lateral regions of the FP mapped to memory and emotion domains, while the dorso- and ventromedial clusters were associated broadly with emotion and social cognition processes. Furthermore, the dorsomedial regions contain an emphasis on theory of mind and affective related paradigms whereas ventromedial regions couple with reward tasks. Results from this study support previous segregations of the FP and provide meta-analytic contributions to the ongoing discussion of elucidating functional architecture within human FP. PMID:26254112

  16. Quadriceps and Hamstrings Coactivation During Common Therapeutic Exercises

    PubMed Central

    Begalle, Rebecca L.; DiStefano, Lindsay J.; Blackburn, Troy; Padua, Darin A.

    2012-01-01

    Context Anterior tibial shear force and knee valgus moment increase anterior cruciate ligament (ACL) loading. Muscle coactivation of the quadriceps and hamstrings influences anterior tibial shear force and knee valgus moment, thus potentially influencing ACL loading and injury risk. Therefore, identifying exercises that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in ACL injury rehabilitation and prevention. Objective To quantify and compare quadriceps with hamstrings coactivation electromyographic (EMG) ratios during commonly used closed kinetic chain exercises. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants Twenty-seven healthy, physically active volunteers (12 men, 15 women; age = 22.1 ± 3.1 years, height = 171.4 ± 10 cm, mass = 72.4 ± 16.7 kg). Intervention(s) Participants completed 9 separate closed chain therapeutic exercises in a randomized order. Main Outcome Measure(s) Surface electromyography quantified the activity level of the vastus medialis (VM), vastus lateralis (VL), medial hamstrings (MH), and biceps femoris (BF) muscles. The quadriceps-to-hamstrings (Q:H) coactivation ratio was computed as the sum of average quadriceps (VM, VL) EMG amplitude divided by the sum of average hamstrings (MH, BF) EMG amplitude for each trial. We used repeated-measures analyses of variance to compare Q:H ratios and individual muscle contributions across exercises (α = .05), then used post hoc Tukey analyses. Results We observed a main effect for exercise (F3,79 = 22.6, P < .001). The post hoc Tukey analyses revealed smaller Q:H ratios during the single-limb dead lift (2.87 ± 1.77) than the single-limb squat (5.52 ± 2.89) exercise. The largest Q:H ratios were observed during the transverse-lunge (7.78 ± 5.51, P < .001), lateral-lunge (9.30 ± 5.53, P < .001), and forward-lunge (9.70 ± 5.90, P < .001) exercises. Conclusions The most balanced (smallest) coactivation ratios were

  17. Play Therapy

    PubMed Central

    Kool, Ritesh

    2010-01-01

    Play therapy represents a unique form of treatment that is not only geared toward young children, but is translated into a language children can comprehend and utilize—the language of play. For the referring provider or practitioner, questions may remain regarding the nature, course, and efficacy of play therapy. This article reviews the theoretical underpinnings of play therapy, some practical considerations, and finally a summary of the current state of research in regard to play therapy. The authors present the practicing psychiatrist with a road map for referring a patient to play therapy or initiating it in appropriate cases. PMID:21103141

  18. Development of potent small-molecule inhibitors to drug the undruggable steroid receptor coactivator-3

    PubMed Central

    Song, Xianzhou; Chen, Jianwei; Zhao, Mingkun; Zhang, Chengwei; Yu, Yang; Lonard, David M.; Chow, Dar-Chone; Palzkill, Timothy; Xu, Jianming; O’Malley, Bert W.; Wang, Jin

    2016-01-01

    Protein–protein interactions (PPIs) play a central role in most biological processes, and therefore represent an important class of targets for therapeutic development. However, disrupting PPIs using small-molecule inhibitors (SMIs) is challenging and often deemed as “undruggable.” We developed a cell-based functional assay for high-throughput screening to identify SMIs for steroid receptor coactivator-3 (SRC-3 or AIB1), a large and mostly unstructured nuclear protein. Without any SRC-3 structural information, we identified SI-2 as a highly promising SMI for SRC-3. SI-2 meets all of the criteria of Lipinski’s rule [Lipinski et al. (2001) Adv Drug Deliv Rev 46(1-3):3–26] for a drug-like molecule and has a half-life of 1 h in a pharmacokinetics study and a reasonable oral availability in mice. As a SRC-3 SMI, SI-2 can selectively reduce the transcriptional activities and the protein concentrations of SRC-3 in cells through direct physical interactions with SRC-3, and selectively induce breast cancer cell death with IC50 values in the low nanomolar range (3–20 nM), but not affect normal cell viability. Furthermore, SI-2 can significantly inhibit primary tumor growth and reduce SRC-3 protein levels in a breast cancer mouse model. In a toxicology study, SI-2 caused minimal acute cardiotoxicity based on a hERG channel blocking assay and an unappreciable chronic toxicity to major organs based on histological analyses. We believe that this work could significantly improve breast cancer treatment through the development of “first-in-class” drugs that target oncogenic coactivators. PMID:27084884

  19. Sertad1 encodes a novel transcriptional co-activator of SMAD1 in mouse embryonic hearts

    SciTech Connect

    Peng, Yin; Zhao, Shaomin; Song, Langying; Wang, Manyuan; Jiao, Kai

    2013-11-29

    Highlights: •SERTAD1 interacts with SMAD1. •Sertad1 is expressed in mouse embryonic hearts. •SERTAD1 is localized in both cytoplasm and nucleus of cardiomyocytes. •SERTAD1 enhances expression of BMP target cardiogenic genes as a SMAD1 co-activator. -- Abstract: Despite considerable advances in surgical repairing procedures, congenital heart diseases (CHDs) remain the leading noninfectious cause of infant morbidity and mortality. Understanding the molecular/genetic mechanisms underlying normal cardiogenesis will provide essential information for the development of novel diagnostic and therapeutic strategies against CHDs. BMP signaling plays complex roles in multiple cardiogenic processes in mammals. SMAD1 is a canonical nuclear mediator of BMP signaling, the activity of which is critically regulated through its interaction partners. We screened a mouse embryonic heart yeast two-hybrid library using Smad1 as bait and identified SERTAD1 as a novel interaction partner of SMAD1. SERTAD1 contains multiple potential functional domains, including two partially overlapping transactivation domains at the C terminus. The SERTAD1-SMAD1 interaction in vitro and in mammalian cells was further confirmed through biochemical assays. The expression of Sertad1 in developing hearts was demonstrated using RT-PCR, western blotting and in situ hybridization analyses. We also showed that SERTAD1 was localized in both the cytoplasm and nucleus of immortalized cardiomyocytes and primary embryonic cardiomyocyte cultures. The overexpression of SERTAD1 in cardiomyocytes not only enhanced the activity of two BMP reporters in a dose-dependent manner but also increased the expression of several known BMP/SMAD regulatory targets. Therefore, these data suggest that SERTAD1 acts as a SMAD1 transcriptional co-activator to promote the expression of BMP target genes during mouse cardiogenesis.

  20. TBLR1 as an AR coactivator selectively activates AR target genes to inhibit prostate cancer growth

    PubMed Central

    Daniels, Garrett; Li, Yirong; Gellert, Lan Lin; Zhou, Albert; Melamed, Jonathan; Wu, Xinyu; Zhang, Xinming; Zhang, David; Meruelo, Daniel; Logan, Susan K.; Basch, Ross; Lee, Peng

    2014-01-01

    Androgen Receptor (AR), a steroid hormone receptor, is critical for prostate cancer growth. However, activation of AR by androgens can also lead to growth suppression and differentiation. Transcriptional cofactors play an important role in this switch between proliferative and anti-proliferative AR target gene programs. TBLR1, a core component of the nuclear receptor corepressor (NCoR) complex, shows both co-repressor and co-activator activities on nuclear receptors, but little is known about its effects on AR and prostate cancer. We characterized TBLR1 as a coactivator of AR in prostate cancer cells and the activation is both phosphorylation and 19S proteosome dependent. We showed that TBLR1 physically interacts with AR and directly occupies the androgen response elements of affected AR target genes in an androgen-dependent manner. TBLR1 is primarily localized in the nucleus in benign prostate cells and nuclear expression is significantly reduced in prostate cancer cells in culture. Similarly, in human tumor samples, the expression of TBLR1 in the nucleus is significantly reduced in the malignant glands compared to the surrounding benign prostatic glands (p<0.005). Stable ectopic expression of nuclear TBLR1 leads to androgen-dependent growth suppression of prostate cancer cells in vitro and in vivo by selective activation of androgen regulated genes associated with differentiation (e.g. KRT18) and growth suppression (e.g. NKX3.1), but not cell proliferation of the prostate. Understanding the molecular switches involved in the transition from AR dependent growth promotion to AR dependent growth suppression will lead to more successful prostate cancer treatments. PMID:24243687

  1. The Steroid Receptor Coactivator-3 Is Required for the Development of Castration-resistant Prostate Cancer

    PubMed Central

    Tien, Jean Ching-Yi; Liu, Zhaoliang; Liao, Lan; Wang, Fen; Xu, Yixiang; Wu, Ye-Lin; Zhou, Niya; Ittmann, Michael; Xu, Jianming

    2013-01-01

    The transcriptional coactivator SRC-3 plays a key role to enhance prostate cancer (CaP) cell proliferation. Although SRC-3 is highly expressed in advanced CaP, its role in castration resistant CaP (CRPC) driven by PTEN mutation is unknown. We documented elevated SRC-3 in human CRPC and in PTEN-negative human CaP. Patients with high SRC-3 and undetectable PTEN exhibited decreased recurrence-free survival. To explore the causal relationship in these observations, we generated mice in which both Pten and SRC-3 were inactivated in prostate epithelial cells (Pten3CKO mice), comparing them to mice in which only Pten was inactivated in these cells (PtenCKO mice). SRC-3 deletion impaired cellular proliferation and reduced tumor size. Notably, while castration of PtenCKO control mice increased the aggressiveness of prostate tumors relative to non-castrated counterparts, deletion of SRC-3 in Pten3CKO mice reversed all these changes. In support of this finding, castrated Pten3CKO mice also exhibited decreased levels of phospho-Akt, S6 kinase (RPS6KB1) and phosphorylated S6 protein (RPS6), all of which mediate cell growth and proliferation. Moreover, these tumors appeared to be more differentiated as evidenced by higher levels of Fkbp5, an AR-responsive gene that inhibits Akt signaling. Lastly, these tumors also displayed lower levels of certain androgen-repressed genes such as cyclin E2 and MMP10. Together, our results show that SRC-3 drives CRPC formation and offer preclinical proof of concept for a transcriptional coactivator as a therapeutic target to abrogate CRPC progression. PMID:23650284

  2. ICA model order selection of task co-activation networks.

    PubMed

    Ray, Kimberly L; McKay, D Reese; Fox, Peter M; Riedel, Michael C; Uecker, Angela M; Beckmann, Christian F; Smith, Stephen M; Fox, Peter T; Laird, Angela R

    2013-01-01

    Independent component analysis (ICA) has become a widely used method for extracting functional networks in the brain during rest and task. Historically, preferred ICA dimensionality has widely varied within the neuroimaging community, but typically varies between 20 and 100 components. This can be problematic when comparing results across multiple studies because of the impact ICA dimensionality has on the topology of its resultant components. Recent studies have demonstrated that ICA can be applied to peak activation coordinates archived in a large neuroimaging database (i.e., BrainMap Database) to yield whole-brain task-based co-activation networks. A strength of applying ICA to BrainMap data is that the vast amount of metadata in BrainMap can be used to quantitatively assess tasks and cognitive processes contributing to each component. In this study, we investigated the effect of model order on the distribution of functional properties across networks as a method for identifying the most informative decompositions of BrainMap-based ICA components. Our findings suggest dimensionality of 20 for low model order ICA to examine large-scale brain networks, and dimensionality of 70 to provide insight into how large-scale networks fractionate into sub-networks. We also provide a functional and organizational assessment of visual, motor, emotion, and interoceptive task co-activation networks as they fractionate from low to high model-orders.

  3. ICA model order selection of task co-activation networks

    PubMed Central

    Ray, Kimberly L.; McKay, D. Reese; Fox, Peter M.; Riedel, Michael C.; Uecker, Angela M.; Beckmann, Christian F.; Smith, Stephen M.; Fox, Peter T.; Laird, Angela R.

    2013-01-01

    Independent component analysis (ICA) has become a widely used method for extracting functional networks in the brain during rest and task. Historically, preferred ICA dimensionality has widely varied within the neuroimaging community, but typically varies between 20 and 100 components. This can be problematic when comparing results across multiple studies because of the impact ICA dimensionality has on the topology of its resultant components. Recent studies have demonstrated that ICA can be applied to peak activation coordinates archived in a large neuroimaging database (i.e., BrainMap Database) to yield whole-brain task-based co-activation networks. A strength of applying ICA to BrainMap data is that the vast amount of metadata in BrainMap can be used to quantitatively assess tasks and cognitive processes contributing to each component. In this study, we investigated the effect of model order on the distribution of functional properties across networks as a method for identifying the most informative decompositions of BrainMap-based ICA components. Our findings suggest dimensionality of 20 for low model order ICA to examine large-scale brain networks, and dimensionality of 70 to provide insight into how large-scale networks fractionate into sub-networks. We also provide a functional and organizational assessment of visual, motor, emotion, and interoceptive task co-activation networks as they fractionate from low to high model-orders. PMID:24339802

  4. A histone chaperone, DEK, transcriptionally coactivates a nuclear receptor

    PubMed Central

    Sawatsubashi, Shun; Murata, Takuya; Lim, Jinseon; Fujiki, Ryoji; Ito, Saya; Suzuki, Eriko; Tanabe, Masahiko; Zhao, Yue; Kimura, Shuhei; Fujiyama, Sally; Ueda, Takashi; Umetsu, Daiki; Ito, Takashi; Takeyama, Ken-ichi; Kato, Shigeaki

    2010-01-01

    Chromatin reorganization is essential for transcriptional control by sequence-specific transcription factors. However, the molecular link between transcriptional control and chromatin reconfiguration remains unclear. By colocalization of the nuclear ecdysone receptor (EcR) on the ecdysone-induced puff in the salivary gland, Drosophila DEK (dDEK) was genetically identified as a coactivator of EcR in both insect cells and intact flies. Biochemical purification and characterization of the complexes containing fly and human DEKs revealed that DEKs serve as histone chaperones via phosphorylation by forming complexes with casein kinase 2. Consistent with the preferential association of the DEK complex with histones enriched in active epigenetic marks, dDEK facilitated H3.3 assembly during puff formation. In some human myeloid leukemia patients, DEK was fused to CAN by chromosomal translocation. This mutation significantly reduced formation of the DEK complex, which is required for histone chaperone activity. Thus, the present study suggests that at least one histone chaperone can be categorized as a type of transcriptional coactivator for nuclear receptors. PMID:20040570

  5. Steroid receptor coactivator 1 deficiency increases MMTV-neu mediated tumor latency and differentiation specific gene expression, decreases metastasis, and inhibits response to PPAR ligands

    PubMed Central

    2010-01-01

    Background The peroxisome proliferator activated receptor (PPAR) subgroup of the nuclear hormone receptor superfamily is activated by a variety of natural and synthetic ligands. PPARs can heterodimerize with retinoid X receptors, which have homology to other members of the nuclear receptor superfamily. Ligand binding to PPAR/RXRs results in recruitment of transcriptional coactivator proteins such as steroid receptor coactivator 1 (SRC-1) and CREB binding protein (CBP). Both SRC-1 and CBP are histone acetyltransferases, which by modifying nucleosomal histones, produce more open chromatin structure and increase transcriptional activity. Nuclear hormone receptors can recruit limiting amounts of coactivators from other transcription factor binding sites such as AP-1, thereby inhibiting the activity of AP-1 target genes. PPAR and RXR ligands have been used in experimental breast cancer therapy. The role of coactivator expression in mammary tumorigenesis and response to drug therapy has been the subject of recent studies. Methods We examined the effects of loss of SRC-1 on MMTV-neu mediated mammary tumorigenesis. Results SRC-1 null mutation in mammary tumor prone mice increased the tumor latency period, reduced tumor proliferation index and metastasis, inhibited response to PPAR and RXR ligands, and induced genes involved in mammary gland differentiation. We also examined human breast cancer cell lines overexpressing SRC-1 or CBP. Coactivator overexpression increased cellular proliferation with resistance to PPAR and RXR ligands and remodeled chromatin of the proximal epidermal growth factor receptor promoter. Conclusions These results indicate that histone acetyltransferases play key roles in mammary tumorigenesis and response to anti-proliferative therapies. PMID:21080969

  6. City Play.

    ERIC Educational Resources Information Center

    Dargan, Amanda; Zeitlin, Steve

    2000-01-01

    Today, fewer city blocks preserve the confidence of lifestyle and urban geography that sustain traditional games and outdoor play. Large groups of children choosing sides and organizing Red Rover games are no longer commonplace. Teachers must encourage free play; urban planners must build cities that are safe play havens. (MLH)

  7. Wanna Play?

    ERIC Educational Resources Information Center

    Chenfeld, Mimi Brodsky

    2006-01-01

    In this article, the author talks about the importance of play in the lives of children and describes how games and imaginative play contribute to the development of children. From her decades-old collection of countless incidents demonstrating children's love for self-directed, informal, imaginative play, the author shares three incidents that…

  8. City Play.

    ERIC Educational Resources Information Center

    Dargan, Amanda; Zeitlin, Steve

    2000-01-01

    Today, fewer city blocks preserve the confidence of lifestyle and urban geography that sustain traditional games and outdoor play. Large groups of children choosing sides and organizing Red Rover games are no longer commonplace. Teachers must encourage free play; urban planners must build cities that are safe play havens. (MLH)

  9. Play Therapy

    PubMed Central

    Lawver, Timothy; Blankenship, Kelly

    2008-01-01

    Play therapy is a treatment modality in which the therapist engages in play with the child. Its use has been documented in a variety of settings and with a variety of diagnoses. Treating within the context of play brings the therapist and the therapy to the level of the child. By way of an introduction to this approach, a case is presented of a six-year-old boy with oppositional defiant disorder. The presentation focuses on the events and interactions of a typical session with an established patient. The primary issues of the session are aggression, self worth, and self efficacy. These themes manifest themselves through the content of the child’s play and narration of his actions. The therapist then reflects these back to the child while gently encouraging the child toward more positive play. Though the example is one of nondirective play therapy, a wide range of variation exists under the heading of play therapy. PMID:19724720

  10. Coactivation of Lower Limb Muscles during Gait in Patients with Multiple Sclerosis

    PubMed Central

    Boudarham, Julien; Hameau, Sophie; Zory, Raphael; Hardy, Alexandre; Bensmail, Djamel; Roche, Nicolas

    2016-01-01

    Background Coactivation of agonist and antagonist lower limb muscles during gait stiffens joints and ensures stability. In patients with multiple sclerosis, coactivation of lower limb muscles might be a compensatory mechanism to cope with impairments of balance and gait. Objective The aim of this study was to assess coactivation of agonist and antagonist muscles at the knee and ankle joints during gait in patients with multiple sclerosis, and to evaluate the relationship between muscle coactivation and disability, gait performance, dynamic ankle strength measured during gait, and postural stability. Methods The magnitude and duration of coactivation of agonist-antagonist muscle pairs at the knee and ankle were determined for both lower limbs (more and less-affected) in 14 patients with multiple sclerosis and 11 healthy subjects walking at a spontaneous speed, using 3D-gait analysis. Results In the patient group, coactivation was increased in the knee muscles during single support (proximal strategy) and in the ankle muscles during double support (distal strategy). The magnitude of coactivation was highest in the patients with the slowest gait, the greatest motor impairment and the most instability. Conclusion Increased muscle coactivation is likely a compensatory mechanism to limit the number of degrees of freedom during gait in patients with multiple sclerosis, particularly when postural stability is impaired. PMID:27336442

  11. Measuring Mathematics Teachers' Professional Competence by Using Video Clips (COACTIV Video)

    ERIC Educational Resources Information Center

    Bruckmaier, G.; Krauss, S.; Blum, W.; Leiss, D.

    2016-01-01

    The COACTIV video study is part of the COACTIV research program in which secondary mathematics teachers whose students participated in PISA 03/04 were examined, with respect to their professional knowledge, motivational orientations, beliefs, and self-regulation. In the video study, 284 German secondary mathematics teachers were asked to specify…

  12. Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

    PubMed Central

    Rothmuller, C; Cafarelli, E

    1995-01-01

    1. Biceps femoris antagonist coactivation increases during progressive fatigue. Our purpose was to determine if the mechanism that increases coactivation during fatigue is susceptible to vibration. Vibration drives alpha-motoneurons via the Ia loop, producing force without descending motor drive, and thus uncoupling antagonist and agonist activation. Evidence that vibration increases coactivation disproportionately from its 'common drive' would suggest the possibility that some of the effects of fatigue are mediated through a segmental reflex loop. 2. Ten male subjects performed repeated maximal voluntary isometric contractions (MVCs) of the knee extensors of one leg. Paired submaximal test contractions (50% of MVC), without visual feedback, were performed when MVC reached 85, 70 and then 50% of its initial value. Vibration was applied to the patellar tendon during one test contraction in each pair. 3. Vibration reduced test contraction force below control values. However, coactivation increased at the same rate in both conditions. Biceps femoris coactivation was greater during vibration, but did not change during fatigue in either condition. 4. Our observations suggest that agonist-antagonist muscle pairs are controlled as a single motor unit pool by a common central drive. Vibrating the agonist increases antagonist coactivity, but does not alter the rate at which coactivation increases during fatigue. This supports the idea that agonist coactivation is controlled by a central mechanism. PMID:7562623

  13. Effect of vibration on antagonist muscle coactivation during progressive fatigue in humans.

    PubMed

    Rothmuller, C; Cafarelli, E

    1995-06-15

    1. Biceps femoris antagonist coactivation increases during progressive fatigue. Our purpose was to determine if the mechanism that increases coactivation during fatigue is susceptible to vibration. Vibration drives alpha-motoneurons via the Ia loop, producing force without descending motor drive, and thus uncoupling antagonist and agonist activation. Evidence that vibration increases coactivation disproportionately from its 'common drive' would suggest the possibility that some of the effects of fatigue are mediated through a segmental reflex loop. 2. Ten male subjects performed repeated maximal voluntary isometric contractions (MVCs) of the knee extensors of one leg. Paired submaximal test contractions (50% of MVC), without visual feedback, were performed when MVC reached 85, 70 and then 50% of its initial value. Vibration was applied to the patellar tendon during one test contraction in each pair. 3. Vibration reduced test contraction force below control values. However, coactivation increased at the same rate in both conditions. Biceps femoris coactivation was greater during vibration, but did not change during fatigue in either condition. 4. Our observations suggest that agonist-antagonist muscle pairs are controlled as a single motor unit pool by a common central drive. Vibrating the agonist increases antagonist coactivity, but does not alter the rate at which coactivation increases during fatigue. This supports the idea that agonist coactivation is controlled by a central mechanism.

  14. Play Sheets. Let's Play! Project.

    ERIC Educational Resources Information Center

    State Univ. of New York, Buffalo. Center for Assistive Technology.

    This collection of play sheets for parents and early intervention personnel was developed by the "Let's Play! Project," a 3-year federally supported project that worked to promote play in infants and toddlers with disabilities through the use of "low-tech" assistive technology. Each single page guide provides guidance to…

  15. Pontin functions as an essential coactivator for Oct4-dependent lincRNA expression in mouse embryonic stem cells

    PubMed Central

    Boo, Kyungjin; Bhin, Jinhyuk; Jeon, Yoon; Kim, Joomyung; Shin, Hi-Jai R.; Park, Jong-Eun; Kim, Kyeongkyu; Kim, Chang Rok; Jang, Hyonchol; Kim, In-Hoo; Kim, V. Narry; Hwang, Daehee; Lee, Ho; Baek, Sung Hee

    2015-01-01

    The actions of transcription factors, chromatin modifiers and noncoding RNAs are crucial for the programming of cell states. Although the importance of various epigenetic machineries for controlling pluripotency of embryonic stem (ES) cells has been previously studied, how chromatin modifiers cooperate with specific transcription factors still remains largely elusive. Here, we find that Pontin chromatin remodelling factor plays an essential role as a coactivator for Oct4 for maintenance of pluripotency in mouse ES cells. Genome-wide analyses reveal that Pontin and Oct4 share a substantial set of target genes involved in ES cell maintenance. Intriguingly, we find that the Oct4-dependent coactivator function of Pontin extends to the transcription of large intergenic noncoding RNAs (lincRNAs) and in particular linc1253, a lineage programme repressing lincRNA, is a Pontin-dependent Oct4 target lincRNA. Together, our findings demonstrate that the Oct4-Pontin module plays critical roles in the regulation of genes involved in ES cell fate determination. PMID:25857206

  16. Simultaneous absorption of SO2 and NO from flue gas using ultrasound/Fe(2+)/heat coactivated persulfate system.

    PubMed

    Liu, Yangxian; Liu, Ziyang; Wang, Yan; Yin, Yanshan; Pan, Jianfeng; Zhang, Jun; Wang, Qian

    2017-08-19

    A novel process on simultaneous absorption of SO2 and NO from flue gas using ultrasound (US)/Fe(2+)/heat coactivated persulfate system was proposed. The influencing factors, active species, products and mechanism of SO2 and NO removal were investigated. The results indicate that US enhances NO removal due to enhancement of mass transfer and chemical reaction. US of 28kHz is more effective than that of 40kHz. NO removal efficiency increases with increasing persulfate concentration, ultrasonic power density and Fe(2+) concentration (at high persulfate concentration). Solution pH, solution temperature and Fe(2+) concentration (at low persulfate concentration) have double effect on NO removal. SO2 is completely removed in most of tested removal systems, except for using water absorption. US, Fe(2+) and heat have a synergistic effect for activating persulfate to produce free radicals, and US/Fe(2+)/heat coactivated persulfate system achieves the highest NO removal efficiency. ·OH and SO4(-)· play a leading role for NO oxidation, and persulfate only plays a complementary role for NO oxidation. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Pretend play.

    PubMed

    Weisberg, Deena Skolnick

    2015-01-01

    Pretend play is a form of playful behavior that involves nonliteral action. Although on the surface this activity appears to be merely for fun, recent research has discovered that children's pretend play has connections to important cognitive and social skills, such as symbolic thinking, theory of mind, and counterfactual reasoning. The current article first defines pretend play and then reviews the arguments and evidence for these three connections. Pretend play has a nonliteral correspondence to reality, hence pretending may provide children with practice with navigating symbolic relationships, which may strengthen their language skills. Pretend play and theory of mind reasoning share a focus on others' mental states in order to correctly interpret their behavior, hence pretending and theory of mind may be mutually supportive in development. Pretend play and counterfactual reasoning both involve representing nonreal states of affairs, hence pretending may facilitate children's counterfactual abilities. These connections make pretend play an important phenomenon in cognitive science: Studying children's pretend play can provide insight into these other abilities and their developmental trajectories, and thereby into human cognitive architecture and its development. © 2015 John Wiley & Sons, Ltd.

  18. Expression, purification, crystallization and preliminary crystallographic study of isolated modules of the mouse coactivator-associated arginine methyltransferase 1

    SciTech Connect

    Troffer-Charlier, Nathalie; Cura, Vincent; Hassenboehler, Pierre; Moras, Dino; Cavarelli, Jean

    2007-04-01

    Isolated modules of mouse coactivator-associated arginine methyltransferase 1 encompassing the protein arginine N-methyltransferase catalytic domain have been overexpressed, purified and crystallized. X-ray diffraction data have been collected and have enabled determination of the structures by multiple isomorphous replacement using anomalous scattering. Coactivator-associated arginine methyltransferase 1 (CARM1) plays a crucial role in gene expression as a coactivator of several nuclear hormone receptors and also of non-nuclear receptor systems. Its recruitment by the transcriptional machinery induces protein methylation, leading to chromatin remodelling and gene activation. CARM1{sub 28–507} and two structural states of CARM1{sub 140–480} were expressed, purified and crystallized. Crystals of CARM1{sub 28–507} belong to space group P6{sub 2}22, with unit-cell parameters a = b = 136.0, c = 125.3 Å; they diffract to beyond 2.5 Å resolution using synchrotron radiation and contain one monomer in the asymmetric unit. The structure of CARM1{sub 28–507} was solved by multiple isomorphous replacement and anomalous scattering methods. Crystals of apo CARM1{sub 140–480} belong to space group I222, with unit-cell parameters a = 74.6, b = 99.0, c = 207.4 Å; they diffract to beyond 2.7 Å resolution and contain two monomers in the asymmetric unit. Crystals of CARM1{sub 140–480} in complex with S-adenosyl-l-homocysteine belong to space P2{sub 1}2{sub 1}2, with unit-cell parameters a = 74.6, b = 98.65, c = 206.08 Å; they diffract to beyond 2.6 Å resolution and contain four monomers in the asymmetric unit. The structures of apo and holo CARM1{sub 140–480} were solved by molecular-replacement techniques from the structure of CARM1{sub 28–507}.

  19. The protooncogene TCL1 is an Akt kinase coactivator.

    PubMed

    Laine, J; Künstle, G; Obata, T; Sha, M; Noguchi, M

    2000-08-01

    Human T cell prolymphocytic leukemia can result from chromosomal translocations involving 14q32.1 or Xq28 regions. The regions encode a family of protooncogenes (TCL1, MTCP1, and TCL1b) of unknown function. In yeast two-hybrid screening, we found that TCL1 interacts with Akt. All TCL1 isoforms bind to the Akt pleckstrin homology domain. Both in vitro and in vivo TCL1 increases Akt kinase activity and as a consequence enhances substrate phosphorylation. In vivo, TCL1 stabilizes the mitochondrial transmembrane potential and enhances cell proliferation and survival. In vivo, TCL1 forms trimers, which associate with Akt. TCL1 facilitates the oligomerization and activation of Akt. Our data show that TCL1 is a novel Akt kinase coactivator, which promotes Akt-induced cell survival and proliferation.

  20. Shadow Play

    ERIC Educational Resources Information Center

    Trundle, Kathy Cabe; Hilson, Margilee P.

    2012-01-01

    A bunny rabbit playfully hops across the wall. Then hands realign and fingers shift to make a hawk soar toward the ceiling. Most children have enjoyed the delightful experience of playing with shadow puppets. The authors build on this natural curiosity to help students link shadows to complex astronomical concepts such as seasons. The…

  1. Playful Gaming.

    ERIC Educational Resources Information Center

    Makedon, Alex

    1984-01-01

    Discusses the concept of playful gaming (an idea not expressed fully by either term alone) and uses it as an analytical tool to study the playfulness of games in the context of several social phenomena; i.e., social change, socialization, utopian systems, and educational gaming. An extensive reference list is provided. (MBR)

  2. Why Play?

    ERIC Educational Resources Information Center

    Weininger, O.

    This paper draws together briefly theories and knowledge from research in morphology and cognitive psychology, as well as some hypothetical information from traditional psychiatry, to show the ramifications of play in children's development. Play is defined as any of a wide variety of behaviors through which an individual attempts to discover what…

  3. Shadow Play

    ERIC Educational Resources Information Center

    Trundle, Kathy Cabe; Hilson, Margilee P.

    2012-01-01

    A bunny rabbit playfully hops across the wall. Then hands realign and fingers shift to make a hawk soar toward the ceiling. Most children have enjoyed the delightful experience of playing with shadow puppets. The authors build on this natural curiosity to help students link shadows to complex astronomical concepts such as seasons. The…

  4. Playing Shakespeare.

    ERIC Educational Resources Information Center

    Bashian, Kathleen Ryniker

    1993-01-01

    Describes a yearlong project at 12 Catholic middle schools in the Diocese of Arlington, Virginia, to incorporate the plays of William Shakespeare into the curriculum. Teachers attended university lectures and directed students in performances of the plays. Concludes that Shakespeare can be understood and enjoyed by middle school students. (BCY)

  5. Heterogeneous fractionation profiles of meta-analytic coactivation networks.

    PubMed

    Laird, Angela R; Riedel, Michael C; Okoe, Mershack; Jianu, Radu; Ray, Kimberly L; Eickhoff, Simon B; Smith, Stephen M; Fox, Peter T; Sutherland, Matthew T

    2017-04-01

    Computational cognitive neuroimaging approaches can be leveraged to characterize the hierarchical organization of distributed, functionally specialized networks in the human brain. To this end, we performed large-scale mining across the BrainMap database of coordinate-based activation locations from over 10,000 task-based experiments. Meta-analytic coactivation networks were identified by jointly applying independent component analysis (ICA) and meta-analytic connectivity modeling (MACM) across a wide range of model orders (i.e., d=20-300). We then iteratively computed pairwise correlation coefficients for consecutive model orders to compare spatial network topologies, ultimately yielding fractionation profiles delineating how "parent" functional brain systems decompose into constituent "child" sub-networks. Fractionation profiles differed dramatically across canonical networks: some exhibited complex and extensive fractionation into a large number of sub-networks across the full range of model orders, whereas others exhibited little to no decomposition as model order increased. Hierarchical clustering was applied to evaluate this heterogeneity, yielding three distinct groups of network fractionation profiles: high, moderate, and low fractionation. BrainMap-based functional decoding of resultant coactivation networks revealed a multi-domain association regardless of fractionation complexity. Rather than emphasize a cognitive-motor-perceptual gradient, these outcomes suggest the importance of inter-lobar connectivity in functional brain organization. We conclude that high fractionation networks are complex and comprised of many constituent sub-networks reflecting long-range, inter-lobar connectivity, particularly in fronto-parietal regions. In contrast, low fractionation networks may reflect persistent and stable networks that are more internally coherent and exhibit reduced inter-lobar communication.

  6. Transcriptional Coactivator PC4, a Chromatin-Associated Protein, Induces Chromatin Condensation▿ †

    PubMed Central

    Das, Chandrima; Hizume, Kohji; Batta, Kiran; Kumar, B. R. Prashanth; Gadad, Shrikanth S.; Ganguly, Semanti; Lorain, Stephanie; Verreault, Alain; Sadhale, Parag P.; Takeyasu, Kunio; Kundu, Tapas K.

    2006-01-01

    Human transcriptional coactivator PC4 is a highly abundant multifunctional protein which plays diverse important roles in cellular processes, including transcription, replication, and repair. It is also a unique activator of p53 function. Here we report that PC4 is a bona fide component of chromatin with distinct chromatin organization ability. PC4 is predominantly associated with the chromatin throughout the stages of cell cycle and is broadly distributed on the mitotic chromosome arms in a punctate manner except for the centromere. It selectively interacts with core histones H3 and H2B; this interaction is essential for PC4-mediated chromatin condensation, as demonstrated by micrococcal nuclease (MNase) accessibility assays, circular dichroism spectroscopy, and atomic force microscopy (AFM). The AFM images show that PC4 compacts the 100-kb reconstituted chromatin distinctly compared to the results seen with the linker histone H1. Silencing of PC4 expression in HeLa cells results in chromatin decompaction, as evidenced by the increase in MNase accessibility. Knocking down of PC4 up-regulates several genes, leading to the G2/M checkpoint arrest of cell cycle, which suggests its physiological role as a chromatin-compacting protein. These results establish PC4 as a new member of chromatin-associated protein family, which plays an important role in chromatin organization. PMID:16982701

  7. The association between antagonist hamstring coactivation and episodes of knee joint shifting and buckling

    PubMed Central

    Segal, N.A.; Nevitt, M.C.; Welborn, R.D.; Nguyen, U.-S.D.T.; Niu, J.; Lewis, C.E.; Felson, D.T.; Frey-Law, L.

    2016-01-01

    SUMMARY Objective Hamstring coactivation during quadriceps activation is necessary to counteract the quadriceps pull on the tibia, but coactivation can be elevated with symptomatic knee osteoarthritis (OA). To guide rehabilitation to attenuate risk for mobility limitations and falls, this study evaluated whether higher antagonistic open kinetic chain hamstring coactivation is associated with knee joint buckling (sudden loss of support) and shifting (a sensation that the knee might give way). Design At baseline, median hamstring coactivation was assessed during maximal isokinetic knee extensor strength testing and at baseline and 24-month follow-up, knee buckling and shifting was self-reported. Associations between tertiles of co-activation and knee (1) buckling, (2) shifting and (3) either buckling or shifting were assessed using logistic regression, adjusted for age, sex, knee OA and pain. Results 1826 participants (1089 women) were included. Mean ± SD age was 61.7 ± 7.7 years, BMI was 30.3 ± 5.5 kg/m2 and 38.2% of knees had OA. There were no consistent statistically significant associations between hamstring coactivation and ipsilateral prevalent or incident buckling or the combination of buckling and shifting. The odds ratios for incident shifting in the highest in comparison with the lowest tertile of coactivation had similar magnitudes in the combined and medial hamstrings, but only reached statistical significance for lateral hamstring coactivation, OR(95%CI) 1.53 (0.99, 2.36). Conclusions Hamstring coactivation during an open kinetic chain quadriceps exercise was not consistently associated with prevalent or incident self-reported knee buckling or shifting in older adults with or at risk for knee OA. PMID:25765501

  8. On the way of revealing coactivator complexes cross-talk during transcriptional activation.

    PubMed

    Krasnov, Aleksey N; Mazina, Marina Yu; Nikolenko, Julia V; Vorobyeva, Nadezhda E

    2016-01-01

    Transcriptional activation is a complex, multistage process implemented by hundreds of proteins. Many transcriptional proteins are organized into coactivator complexes, which participate in transcription regulation at numerous genes and are a driver of this process. The molecular action mechanisms of coactivator complexes remain largely understudied. Relevant publications usually deal with the involvement of these complexes in the entire process of transcription, and only a few studies are aimed to elucidate their functions at its particular stages. This review summarizes available information on the participation of key coactivator complexes in transcriptional activation. The timing of coactivator complex binding/removal has been used for restructuring previously described information about the transcriptional process. Several major stages of transcriptional activation have been distinguished based on the presence of covalent histone modifications and general transcriptional factors, and the recruitment and/or removal phases have been determined for each coactivator included in analysis. Recruitment of Mediator, SWItch/Sucrose Non-Fermentable and NUcleosome Remodeling Factor complexes during transcription activation has been investigated thoroughly; CHD and INOsitol auxotrophy 80 families are less well studied. In most cases, the molecular mechanisms responsible for the removal of certain coactivator complexes after the termination of their functions at the promoters are still not understood. On the basis of the summarized information, we propose a scheme that illustrates the involvement of coactivator complexes in different stages of the transcription activation process. This scheme may help to gain a deeper insight into the molecular mechanism of functioning of coactivator complexes, find novel participants of the process, and reveal novel structural or functional connections between different coactivators.

  9. Expression, purification and primary crystallographic study of human androgen receptor in complex with DNA and coactivator motifs

    SciTech Connect

    Zhou, X. Edward; Suino-Powell, Kelly; Ludidi, Phumzile L.; McDonnell, Donald P.; Xu, H. Eric

    2012-10-24

    The androgen receptor (AR) is a DNA-binding and hormone-activated transcription factor that plays critical roles in the development and progression of prostate cancer. The transcriptional function of AR is modulated by intermolecular interactions with DNA elements and coactivator proteins, as well as intramolecular interactions between AR domains; thus, the structural information from the full-length AR or a multi-domain fragment is essential for understanding the molecular basis of AR functions. Here we report the expression and purification of full-length AR protein and of a fragment containing its DNA-binding and ligand-binding domains connected by the hinge region in the presence of its natural ligand, dihydrotestosterone. Crystals of ligand-bound full-length AR and of the AR fragment in complex with DNA elements and coactivator motifs have been obtained and diffracted to low resolutions. These results help establish a foundation for pursuing further crystallographic studies of an AR/DNA complex.

  10. Sweet Play

    ERIC Educational Resources Information Center

    Leung, Shuk-kwan S.; Lo, Jane-Jane

    2010-01-01

    This article features Sweet play math, a "math by the month" activity that involves decorating and making sugar cubes. Teachers may want to substitute straws, paper squares, alphabet blocks, or such commercially made manipulatives as Unifix[R] cubes for the real sweets. Given no allergy concerns, teachers and students alike would enjoy some sweet…

  11. Game playing.

    PubMed

    Rosin, Christopher D

    2014-03-01

    Game playing has been a core domain of artificial intelligence research since the beginnings of the field. Game playing provides clearly defined arenas within which computational approaches can be readily compared to human expertise through head-to-head competition and other benchmarks. Game playing research has identified several simple core algorithms that provide successful foundations, with development focused on the challenges of defeating human experts in specific games. Key developments include minimax search in chess, machine learning from self-play in backgammon, and Monte Carlo tree search in Go. These approaches have generalized successfully to additional games. While computers have surpassed human expertise in a wide variety of games, open challenges remain and research focuses on identifying and developing new successful algorithmic foundations. WIREs Cogn Sci 2014, 5:193-205. doi: 10.1002/wcs.1278 CONFLICT OF INTEREST: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. © 2014 John Wiley & Sons, Ltd.

  12. Water Play

    ERIC Educational Resources Information Center

    Cline, Jane E.; Smith, Brandy A.

    The inclusion of activities to develop sensory awareness, spatial thinking, and physical dexterity, operationalized through hands-on science lessons such as water play, have long been part of early childhood education. This practical article addresses Next Generation Science Standards K-2 ETS1-3 and K-2 ETS1-2 by having four-year-old…

  13. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  14. Play School

    ERIC Educational Resources Information Center

    Rich, Jennifer L.

    2004-01-01

    This article describes Fifth Dimension, an after-school program which mixes play and computer games to improve the education and social skills of mostly poor, disadvantaged kids. Although Fifth Dimension seems tailor-made for a poor, rural community, its roots are urban. The after-school program was founded by a group of researchers in San Diego…

  15. Playing Teacher.

    ERIC Educational Resources Information Center

    Gilbert, Juan E.

    The acceptance of animation technologies is increasing. Video games, such as Sony PlayStation (SONY, 2002), have become part of the culture for young people from kindergarten through undergraduate school. Animation technologies have been implemented into educational systems in the form of animated pedagogical agents (Johnson, 2000). The research…

  16. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  17. Sweet Play

    ERIC Educational Resources Information Center

    Leung, Shuk-kwan S.; Lo, Jane-Jane

    2010-01-01

    This article features Sweet play math, a "math by the month" activity that involves decorating and making sugar cubes. Teachers may want to substitute straws, paper squares, alphabet blocks, or such commercially made manipulatives as Unifix[R] cubes for the real sweets. Given no allergy concerns, teachers and students alike would enjoy some sweet…

  18. PADI4 acts as a coactivator of Tal1 by counteracting repressive histone arginine methylation

    NASA Astrophysics Data System (ADS)

    Kolodziej, Stephan; Kuvardina, Olga N.; Oellerich, Thomas; Herglotz, Julia; Backert, Ingo; Kohrs, Nicole; Buscató, Estel. La; Wittmann, Sandra K.; Salinas-Riester, Gabriela; Bonig, Halvard; Karas, Michael; Serve, Hubert; Proschak, Ewgenij; Lausen, Jörn

    2014-05-01

    The transcription factor Tal1 is a critical activator or repressor of gene expression in hematopoiesis and leukaemia. The mechanism by which Tal1 differentially influences transcription of distinct genes is not fully understood. Here we show that Tal1 interacts with the peptidylarginine deiminase IV (PADI4). We demonstrate that PADI4 can act as an epigenetic coactivator through influencing H3R2me2a. At the Tal1/PADI4 target gene IL6ST the repressive H3R2me2a mark triggered by PRMT6 is counteracted by PADI4, which augments the active H3K4me3 mark and thus increases IL6ST expression. In contrast, at the CTCF promoter PADI4 acts as a repressor. We propose that the influence of PADI4 on IL6ST transcription plays a role in the control of IL6ST expression during lineage differentiation of hematopoietic stem/progenitor cells. These results open the possibility to pharmacologically influence Tal1 in leukaemia.

  19. Functional insights from structures of coactivator-associated arginine methyltransferase 1 domains

    PubMed Central

    Troffer-Charlier, Nathalie; Cura, Vincent; Hassenboehler, Pierre; Moras, Dino; Cavarelli, Jean

    2007-01-01

    Coactivator-associated arginine methyltransferase 1 (CARM1), a protein arginine methyltransferase recruited by several transcription factors, methylates a large variety of proteins and plays a critical role in gene expression. We report, in this paper, four crystal structures of isolated modules of CARM1. The 1.7 Å crystal structure of the N-terminal domain of CARM1 reveals an unexpected PH domain, a scaffold frequently found to regulate protein–protein interactions in a large variety of biological processes. Three crystal structures of the CARM1 catalytic module, two free and one cofactor-bound forms (refined at 2.55 Å, 2.4 Å and 2.2 Å, respectively) reveal large structural modifications including disorder to order transition, helix to strand transition and active site modifications. The N-terminal and the C-terminal end of CARM1 catalytic module contain molecular switches that may inspire how CARM1 regulates its biological activities by protein–protein interactions. PMID:17882262

  20. Developmental expression of the SRF co-activator MAL in brain: role in regulating dendritic morphology.

    PubMed

    Shiota, Jun; Ishikawa, Mitsuru; Sakagami, Hiroyuki; Tsuda, Masaaki; Baraban, Jay M; Tabuchi, Akiko

    2006-09-01

    The dynamic changes in dendritic morphology displayed by developing and mature neurons have stimulated interest in deciphering the signaling pathways involved. Recent studies have identified megakaryocytic acute leukemia (MAL), a serum response factor (SRF) co-activator, as a key component of a signaling pathway linking changes in the actin cytoskeleton to SRF-mediated transcription. To help define the role of this pathway in regulating dendritic morphology, we have characterized the pattern of MAL expression in the developing and adult brain, and have examined its role in regulating dendritic morphology in cultured cortical neurons. In histological studies of mouse brain, we found prominent expression of MAL in neurons in adult hippocampus and cerebral cortex. MAL immunostaining revealed localization of this protein in neuronal cell bodies and apical dendrites. During development, an increase in MAL expression occurs during the second post-natal week. Expression of dominant negative MAL constructs or MAL siRNA in cortical neurons grown in primary culture reduces the number of dendritic processes and decreases the basal level of SRF-mediated transcription. Taken together, these findings indicate that the MAL-SRF signaling pathway plays a key role in regulating dendritic morphology.

  1. Identification and expression of an encoding steroid receptor coactivator (SRA) in amphioxus (Branchiostoma japonicum).

    PubMed

    Sun, Huanhuan; Gao, Lili; Pang, Qiuxiang; Sun, Lele; Wu, Di; Bai, Yun; Zhao, Bosheng; Dong, Juan

    2013-11-01

    Steroid receptor coactivator (SRA), a class of genes encoding both functional RNA and protein, has been shown to be present in vertebrates but little is known in invertebrates. Here we isolated a cDNA encoding a SRA homolog from amphioxus Branchiostoma japonicum, named AmphiSRA. The cDNA contained a 525 bp open reading frame corresponding to a deduced protein of 174 amino acids with a predicted molecular mass of ~21 kDa. Phylogenetic analysis showed that AmphiSRA was located at the base of its vertebrate counterparts, suggesting that it represents the archetype of vertebrate SRA. The genomic DNA sequence of AmphiSRA contained four exons and three introns, which was similar to B. floridae SRA exon/intron organization. The recombinant SRAP expressed in vitro shows a band with a molecular mass of 21 kDa and western blot confirmed it, which proved it is an encoding isoform. AmphiSRA is found to display a tissue specific expression pattern, with a predominant expression in gill, intestine, testis, neural tube and notochord. The whole-mount in situ hybridization demonstrated the expression of AmphiSRA in all the stages of development assayed. These implicated that SRA maybe play an important role during embryonic development of cephalochordate amphioxus.

  2. Development of Coactivator-Dependent, First-in-Class Therapies for Breast Cancer

    DTIC Science & Technology

    2014-09-01

    AD_________________ Award Number: W81XWH-13-1-0285 TITLE: Development of Coactivator- Dependent ...COACTIVATOR- DEPENDENT FIRST-IN-CLASS THERAPIES FOR BREAST CANCER 5b. GRANT NUMBER W81XWH-13-1-0285 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...through the inhibition of SRCs. However, bufalin has toxicity to the heart, and medicinal chemistry modification is therefore needed to find non -toxic

  3. Sekikaic acid and lobaric acid target a dynamic interface of the coactivator CBP/p300.

    PubMed

    Majmudar, Chinmay Y; Højfeldt, Jonas W; Arevang, Carl J; Pomerantz, William C; Gagnon, Jessica K; Schultz, Pamela J; Cesa, Laura C; Doss, Conor H; Rowe, Steven P; Vásquez, Victor; Tamayo-Castillo, Giselle; Cierpicki, Tomasz; Brooks, Charles L; Sherman, David H; Mapp, Anna K

    2012-11-05

    Capturing a coactivator, naturally: the natural products sekikaic acid and lobaric acid, isolated after a high-throughput screen of a structurally diverse extract collection, effectively target the dynamic binding interfaces of the GACKIX domain of the coactivator CBP/p300. These molecules are the most effective inhibitors of the GACKIX domain yet described and are uniquely selective for this domain. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Synthesis and evaluation of methylsulfonylnitrobenzamides (MSNBAs) as inhibitors of the thyroid hormone receptor-coactivator interaction

    PubMed Central

    Hwang, Jong Yeon; Attia, Ramy R.; Carrillo, Angela K.; Connelly, Michele C.; Guy, R. Kiplin

    2013-01-01

    We previously identified the methylsulfonylnitrobenzoates (MSNBs) that block the interaction of the thyroid hormone receptor with its obligate transcriptional coactivators and prevent thyroid hormone signaling. As part of our lead optimization work we demonstrated that sulfonylnitrophenylthiazoles (SNPTs), which replace the ester linkage of MSNBs with a thiazole, also inhibited coactivator binding to TR. Here we report that replacement of the ester with an amide (methylsulfonylnitrobenzamides, MSNBA) also provides active TR antagonists. PMID:23414840

  5. The transcriptional coactivator TAZ regulates mesenchymal differentiation in malignant glioma

    PubMed Central

    Bhat, Krishna P.L.; Salazar, Katrina L.; Balasubramaniyan, Veerakumar; Wani, Khalida; Heathcock, Lindsey; Hollingsworth, Faith; James, Johanna D.; Gumin, Joy; Diefes, Kristin L.; Kim, Se Hoon; Turski, Alice; Azodi, Yasaman; Yang, Yuhui; Doucette, Tiffany; Colman, Howard; Sulman, Erik P.; Lang, Frederick F.; Rao, Ganesh; Copray, Sjef; Vaillant, Brian D.; Aldape, Kenneth D.

    2011-01-01

    Recent molecular classification of glioblastoma (GBM) has shown that patients with a mesenchymal (MES) gene expression signature exhibit poor overall survival and treatment resistance. Using regulatory network analysis of available expression microarray data sets of GBM, including The Cancer Genome Atlas (TCGA), we identified the transcriptional coactivator with PDZ-binding motif (TAZ), to be highly associated with the MES network. TAZ expression was lower in proneural (PN) GBMs and lower-grade gliomas, which correlated with CpG island hypermethylation of the TAZ promoter compared with MES GBMs. Silencing of TAZ in MES glioma stem cells (GSCs) decreased expression of MES markers, invasion, self-renewal, and tumor formation. Conversely, overexpression of TAZ in PN GSCs as well as murine neural stem cells (NSCs) induced MES marker expression and aberrant osteoblastic and chondrocytic differentiation in a TEAD-dependent fashion. Using chromatin immunoprecipitation (ChIP), we show that TAZ is directly recruited to a majority of MES gene promoters in a complex with TEAD2. The coexpression of TAZ, but not a mutated form of TAZ that lacks TEAD binding, with platelet-derived growth factor-B (PDGF-B) resulted in high-grade tumors with MES features in a murine model of glioma. Our studies uncover a direct role for TAZ and TEAD in driving the MES differentiation of malignant glioma. PMID:22190458

  6. The transcriptional coactivator TAZ regulates mesenchymal differentiation in malignant glioma.

    PubMed

    Bhat, Krishna P L; Salazar, Katrina L; Balasubramaniyan, Veerakumar; Wani, Khalida; Heathcock, Lindsey; Hollingsworth, Faith; James, Johanna D; Gumin, Joy; Diefes, Kristin L; Kim, Se Hoon; Turski, Alice; Azodi, Yasaman; Yang, Yuhui; Doucette, Tiffany; Colman, Howard; Sulman, Erik P; Lang, Frederick F; Rao, Ganesh; Copray, Sjef; Vaillant, Brian D; Aldape, Kenneth D

    2011-12-15

    Recent molecular classification of glioblastoma (GBM) has shown that patients with a mesenchymal (MES) gene expression signature exhibit poor overall survival and treatment resistance. Using regulatory network analysis of available expression microarray data sets of GBM, including The Cancer Genome Atlas (TCGA), we identified the transcriptional coactivator with PDZ-binding motif (TAZ), to be highly associated with the MES network. TAZ expression was lower in proneural (PN) GBMs and lower-grade gliomas, which correlated with CpG island hypermethylation of the TAZ promoter compared with MES GBMs. Silencing of TAZ in MES glioma stem cells (GSCs) decreased expression of MES markers, invasion, self-renewal, and tumor formation. Conversely, overexpression of TAZ in PN GSCs as well as murine neural stem cells (NSCs) induced MES marker expression and aberrant osteoblastic and chondrocytic differentiation in a TEAD-dependent fashion. Using chromatin immunoprecipitation (ChIP), we show that TAZ is directly recruited to a majority of MES gene promoters in a complex with TEAD2. The coexpression of TAZ, but not a mutated form of TAZ that lacks TEAD binding, with platelet-derived growth factor-B (PDGF-B) resulted in high-grade tumors with MES features in a murine model of glioma. Our studies uncover a direct role for TAZ and TEAD in driving the MES differentiation of malignant glioma.

  7. SIP, a novel ankyrin repeat containing protein, sequesters steroid receptor coactivators in the cytoplasm.

    PubMed

    Zhang, Ying; Zhang, Hua; Liang, Jing; Yu, Wenhua; Shang, Yongfeng

    2007-06-06

    Steroid receptor coactivators (SRCs) exert profound effects on animal development and physiology. These coactivators are nuclear proteins and transcription co-regulators that function to facilitate the transcription initiation mediated by nuclear receptors, as well as by other well-known transcription factors. However, how these co-regulators are functionally regulated is poorly understood. During genome-wide screening for SRC-interacting proteins, we identified a novel ankyrin repeat containing protein, SIP (SRC-Interacting Protein), which interacts with SRC coactivators in the cytoplasm. We demonstrated that extracellular stimuli such as the addition of estrogen, induced phosphorylation of SIP in its PEST (Proline, Glutamate, Serine, and Threonine rich) domain by casein kinase II. The phosphorylation of SIP resulted in dissociation of SRC proteins from SIP in the cytoplasm and led to subsequent nuclear translocation of SRC proteins and gene coactivation. Both gain-of-function and loss-of-function experiments indicate that SIP functions to sequester SRC coactivators in the cytoplasm and buffer the availability of these coactivators, thus providing a mechanism for the regulation of the transcription regulators.

  8. Comparison of humeral rotation co-activation of breast cancer population and healthy shoulders.

    PubMed

    Brookham, Rebecca L; Dickerson, Clark R

    2016-08-01

    Upper limb morbidities are common amongst the breast cancer population (BCP) and have a direct impact on independence. Comparing muscle co-activation strategies between BCP and healthy populations may assist in identifying muscle dysfunction and promote clinical interpretation of dysfunction, which could direct preventative and therapeutic interventions. The purposes of this study were to define humeral rotation muscle co-activation of a BCP and to compare it with a previously defined co-activation relationship of a healthy population. Fifty BCP survivors performed 18 isometric internal and external rotation exertions at various postures and intensities. Surface and intramuscular electrodes recorded shoulder muscle activity. BCP co-activation was predicted at r(2)=0.77 during both exertion types. Humeral abduction angle and task intensity were important factors in the prediction of co-activation in both populations. Comparisons made between populations identified differing muscle strategies used by BCP to maintain postural control. Compared to healthy co-activation, the BCP demonstrated greater activation of internal (IR) and external rotator (ER) type muscles during their respective rotation type. The BCP demonstrated increased (⩾8.7%) activation of pectoralis major. This study has provided insight into how BCP muscles compensate during dysfunction. Continued advancement of this knowledge can provide more understanding of dysfunction, promote generation of evidence-based therapies, and can be useful in biomechanical modeling. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Spatial play.

    PubMed

    Forrest, D V

    1978-02-01

    More than sharpening our tools or making them sterile, our task in psychotherapy and analysis is to enliven them, find in them the organic, the animate, and the fecund. For our tools are formed of language, more like living nets than like knives, dies, taps, or templates, and our familiary with them might as well be a marriage of love as one of convenience. One's own onymy (Forrest, 1973) of words and phrases that seem to be one's property and private treasury will include, in the case of a doctor who uses words, several such verbal tools that have acquired greater frequency of use and richer and deeper meanings with experience. For me the word play in its affinity for very spatial senses has grown increasingly helpful in meeting both the practical demands of therapeutic communication and the personal need to maintain theoretical structures to support therapeutic work. I wish here to explore the concept of play--contributions to its definition, its developmental stages, applications of play, and its extended properties.

  10. Ligand-controlled interaction of histone acetyltransferase binding to ORC-1 (HBO1) with the N-terminal transactivating domain of progesterone receptor induces steroid receptor coactivator 1-dependent coactivation of transcription.

    PubMed

    Georgiakaki, Maria; Chabbert-Buffet, Nathalie; Dasen, Boris; Meduri, Geri; Wenk, Sandra; Rajhi, Leila; Amazit, Larbi; Chauchereau, Anne; Burger, Curt W; Blok, Leen J; Milgrom, Edwin; Lombès, Marc; Guiochon-Mantel, Anne; Loosfelt, Hugues

    2006-09-01

    Modulators of cofactor recruitment by nuclear receptors are expected to play an important role in the coordination of hormone-induced transactivation processes. To identify such factors interacting with the N-terminal domain (NTD) of the progesterone receptor (PR), we used this domain as bait in the yeast Sos-Ras two-hybrid system. cDNAs encoding the C-terminal MYST (MOZ-Ybf2/Sas3-Sas2-Tip60 acetyltransferases) domain of HBO1 [histone acetyltransferase binding to the origin recognition complex (ORC) 1 subunit], a member of the MYST acetylase family, were thus selected from a human testis cDNA library. In transiently transfected CV1 cells, the wild-type HBO1 [611 amino acids (aa)] enhanced transcription mediated by steroid receptors, notably PR, mineralocorticoid receptor, and glucocorticoid receptor, and strongly induced PR and estrogen receptor coactivation by steroid receptor coactivator 1a (SRC-1a). As assessed by two-hybrid and glutathione-S-transferase pull-down assays, the HBO1 MYST acetylase domain (aa 340-611) interacts mainly with the NTD, and also contacts the DNA-binding domain and the hinge domains of hormone-bound PR. The HBO1 N-terminal region (aa 1-340) associates additionally with PR ligand-binding domain (LBD). HBO1 was found also to interact through its NTD with SRC-1a in the absence of steroid receptor. The latter coassociation enhanced specifically activation function 2 activation function encompassed in the LBD. Conversely, the MYST acetylase domain specifically enhanced SRC-1 coupling with PR NTD, through a hormone-dependent mechanism. In human embryonic kidney 293 cells expressing human PRA or PRB, HBO1 raised selectively an SRC-1-dependent response of PRB but failed to regulate PRA activity. We show that HBO1 acts through modification of an LBD-controlled structure present in the N terminus of PRB leading to the modulation of SRC-1 functional coupling with activation function 3-mediated transcription. Importantly, real-time RT-PCR analysis

  11. A structural model of the anaphase promoting complex co-activator (Cdh1) and in silico design of inhibitory compounds

    PubMed Central

    Rahimi, H.; Negahdari, B.; Shokrgozar, M.A.; Madadkar-Sobhani, A.; Mahdian, R.; Foroumadi, A.; Amin, M. Kafshdouzi; Karimipoor, M.

    2015-01-01

    Anaphase promoting complex (APC) controls cell cycle and chromosome segregation. The APC activation occurs after binding of co-activators, cdh1 and cdc20. Cdh1 plays a role in cancer pathogenesis and is known as a potential drug target. The main aim of this study was prediction of 3D structure of cdh1 and designing the inhibitory compounds based on the structural model. First, 3D structure of cdh1 was predicted by means of homology modelling and molecular dynamics tools, MODELLER and Gromacs package, respectively. Then, inhibitory compounds were designed using virtual screening and molecular docking by means AutoDock package. The overall structure of cdh1 is propeller like and each DW40 repeat contains four anti-parallel beta-sheets. Moreover, binding pocket of the inhibitory compounds was determined. The results might be helpful in finding a suitable cdh1 inhibitor for the treatment of cancer. PMID:26430458

  12. A structural model of the anaphase promoting complex co-activator (Cdh1) and in silico design of inhibitory compounds.

    PubMed

    Rahimi, H; Negahdari, B; Shokrgozar, M A; Madadkar-Sobhani, A; Mahdian, R; Foroumadi, A; Amin, M Kafshdouzi; Karimipoor, M

    2015-01-01

    Anaphase promoting complex (APC) controls cell cycle and chromosome segregation. The APC activation occurs after binding of co-activators, cdh1 and cdc20. Cdh1 plays a role in cancer pathogenesis and is known as a potential drug target. The main aim of this study was prediction of 3D structure of cdh1 and designing the inhibitory compounds based on the structural model. First, 3D structure of cdh1 was predicted by means of homology modelling and molecular dynamics tools, MODELLER and Gromacs package, respectively. Then, inhibitory compounds were designed using virtual screening and molecular docking by means AutoDock package. The overall structure of cdh1 is propeller like and each DW40 repeat contains four anti-parallel beta-sheets. Moreover, binding pocket of the inhibitory compounds was determined. The results might be helpful in finding a suitable cdh1 inhibitor for the treatment of cancer.

  13. Developing through relationships: an embodied coactive systems framework.

    PubMed

    Mascolo, Michael F

    2013-01-01

    In recent decades, the developmental sciences have undergone a relational turn. Epigenetic (Gottlieb & Lickliter, 2007), embodied (Thompson, 2007), relational (Lerner & Overton, 2008) and systems (Kelso, 2003) approaches are transforming the ways in which we think about the nature and origins of psychological structures. At their most basic level, relational and systems approaches analyze the developmental origins of order and variability not in terms of sets of separable causal forces but instead in analyses of relations between causal systems. From this view, genes and environment, biology and culture, cognition and emotion, self and other, and so forth are inseparable as causal processes in the development of action and experience. Drawing on these principles, this paper contains an outline of an embodied coactive systems framework for understanding how individual psychological structures develop as a product of socially distributed coactions that occur among elements of the extended person-environment system. Based on these principles, a system for the Developmental Analysis of Joint Action is described. This system provides a set of conceptual and empirical tools for making precise assessments of dynamic structure of jointly constructed patterns of thinking, feeling and acting. By tracking developmental changes in joint action, the system allows researchers to track the origins of higher order psychological structures through particular sequences of coconstructive activity. The holistic analytic system is illustrated through microdevelopmental analyses of (1) the joint construction of shoe-tying skill between a 5-year-old boy and a caregiver, and (2) socioemotional organization developing representations of self in a young adult over the course of a single session of psychotherapy.

  14. The variability of co-activation pattern of antagonist muscles in human infant crawling.

    PubMed

    Xiong, Qi L; Wu, Xiao Y; Nong Xiao; Zeng, Si Y; Zheng, Xiao L; Di Wu; Hou, Wen S

    2016-08-01

    Infant crawling is part of normal human gross motor development, and a 4-beat gait that involves rhythmical flexion and extension of limbs and the underlying muscle co-activation of antagonist muscle around the joint. However, detection the co-activation pattern of antagonist muscle are sparse due to the general difficulty of measuring locomotion in human infants. In this paper, sEMG of antagonist muscles and the corresponding kinematics data of limbs were collected when infants were crawling on hands and knees at their self-selected speed. The infant's gross motor developmental status was assessed by the global Gross Motor Function Measure Scale (GMFM-88) as well. The method based on EMG-EMG plots was used to quantify the variability of co-activation pattern of antagonist muscle. After that, we observed that antagonist muscles of upper limb (triceps brachii and biceps brachii) showed less variability of co-activation pattern of muscles than lower limb(quadriceps femoris and hamstrings) during crawling, and this variability was also varied in different crawling phases (stance and swing). Furthermore, we found some varied behaviors in the co-activation patterns of antagonist muscles when gross motor developmental level increased. The preliminary work suggests that such adaptive changes may be related to the adjustment of neuromuscular in the early stage of gross motor development.

  15. Identification of SRC3/AIB1 as a Preferred Coactivator for Hormone-activated Androgen Receptor

    SciTech Connect

    Zhou, X. Edward; Suino-Powell, Kelly M.; Li, Jun; He, Yuanzheng; MacKeigan, Jeffrey P.; Melcher, Karsten; Yong, Eu-Leong; Xu, H.Eric

    2010-09-17

    Transcription activation by androgen receptor (AR), which depends on recruitment of coactivators, is required for the initiation and progression of prostate cancer, yet the mechanisms of how hormone-activated AR interacts with coactivators remain unclear. This is because AR, unlike any other nuclear receptor, prefers its own N-terminal FXXLF motif to the canonical LXXLL motifs of coactivators. Through biochemical and crystallographic studies, we identify that steroid receptor coactivator-3 (SRC3) (also named as amplified in breast cancer-1 or AIB1) interacts strongly with AR via synergistic binding of its first and third LXXLL motifs. Mutagenesis and functional studies confirm that SRC3 is a preferred coactivator for hormone-activated AR. Importantly, AR mutations found in prostate cancer patients correlate with their binding potency to SRC3, corroborating with the emerging role of SRC3 as a prostate cancer oncogene. These results provide a molecular mechanism for the selective utilization of SRC3 by hormone-activated AR, and they link the functional relationship between AR and SRC3 to the development and growth of prostate cancer.

  16. The Hippo coactivator YAP1 mediates EGFR overexpression and confers chemo-resistance in esophageal cancer

    PubMed Central

    Song, Shumei; Honjo, Soichiro; Jin, Jiankang; Chang, Shih-Shin; Scott, Ailing W; Chen, Qiongrong; Kalhor, Neda; Correa, Arlene M.; Hofstetter, Wayne L.; Albarracin, Constance T.; Wu, Tsung-Teh; Johnson, Randy L.; Hung, Mien-Chie; Ajani, Jaffer A.

    2015-01-01

    Purpose Esophageal cancer (EC) is an aggressive malignancy and often resistant to therapy. Overexpression of EGFR has been associated with poor prognosis of EC patients. However, clinical trials using EGFR inhibitors have not provided benefit for EC patients. Failure of EGFR inhibition may be due to crosstalk with other oncogenic pathways. Experimental Design In this study, expression of YAP1 and EGFR were examined in EAC resistant tumor tissues vs sensitive tissues by immunohistochemistry. Western blot, immunofluorescence, real-time PCR, promoter analysis, site-directed mutagenesis and in vitro and in vivo functional assays were performed to elucidate the YAP1 mediate EGFR expression and transcription and the relationship with chemoresistance in esophageal cancer. Results We demonstrate that Hippo pathway coactivator YAP1 can induce EGFR expression and transcription in multiple cell systems. Both YAP1 and EGFR are overexpressed in resistant EC tissues compared to sensitive EC tissues. Further, we found that YAP1 increases EGFR expression at the level of transcription requiring an intact TEAD binding site in the EGFR promoter. Most importantly, exogenous induction of YAP1 induces resistance to 5-FU and docetaxcel, while knockdown of YAP sensitizes EC cells to these cytotoxics. Verteporfin, a YAP1 inhibitor, effectively inhibits both YAP1 and EGFR expression and sensitizes cells to cytotoxics. Conclusions Our data provide evidence that YAP1 up-regulation of EGFR plays an important role in conferring therapy resistance in EC cells. Targeting YAP1-EGFR axis may be more efficacious than targeting EGFR alone in EC. PMID:25739674

  17. The CREB Coactivator CRTC3 Links Catecholamine Signaling to Energy Balance

    PubMed Central

    Song, Youngsup; Altarejos, Judith; Goodarzi, Mark O.; Inoue, Hiroshi; Guo, Xiuqing; Berdeaux, Rebecca; Kim, Jeong-Ho; Goode, Jason; Igata, Motoyuki; Paz, Jose; Hogan, Meghan F.; Singh, Pankaj K.; Goebel, Naomi; Vera, Lili; Miller, Nina; Cui, Jinrui; Jones, Michelle R.; Consortium, CHARGE; Consortium, GIANT; Chen, Yii-Der I.; Taylor, Kent D.; Hsueh, Willa A.; Rotter, Jerome I.; Montminy, Marc

    2011-01-01

    Under lean conditions, the adipose-derived hormone leptin maintains energy balance in part through CNS-mediated increases in sympathetic outflow that enhance fat burning 1,2. Triggering of beta adrenergic receptors in adipocytes stimulates energy expenditure via cAMP-dependent increases in lipolysis and fatty acid oxidation 3. Although the underlying mechanism is unclear, catecholamine signaling in fat cells is thought to be disrupted in obesity 4, where it may contribute to the ectopic accumulation of lipid in liver and to the development of insulin resistance 5,6. Here we show that the cAMP responsive CREB coactivator CRTC3 promotes obesity by attenuating beta adrenergic receptor signaling in adipose; mice with a knockout of the CRTC3 gene have increased energy expenditure, are resistant to diet induced obesity, and are protected from the development of hepatic steatosis under high fat diet feeding conditions. CRTC3 was activated in response to catecholamine signals, when it reduced adenyl cyclase activity by upregulating the expression of RGS2 7–9, a metabolic syndrome susceptibility gene 10, which we show here is also a direct target of CREB and CRTC3. RGS2 expression was down-regulated in adipocytes from CRTC3−/− mice, leading to increases in insulin and catecholamine signaling that enhanced glucose and fatty acid oxidation. As a common human CRTC3 variant (Ser72Asn), with increased transcriptional activity, is associated with several anthropometric indices of adiposity in two distinct Mexican-American cohorts, our results suggest that adipocyte CRTC3 may play a role in the development of obesity in this population. PMID:21164481

  18. Expression, purification, crystallization and preliminary crystallographic study of isolated modules of the mouse coactivator-associated arginine methyltransferase 1

    PubMed Central

    Troffer-Charlier, Nathalie; Cura, Vincent; Hassenboehler, Pierre; Moras, Dino; Cavarelli, Jean

    2007-01-01

    Coactivator-associated arginine methyltransferase 1 (CARM1) plays a crucial role in gene expression as a coactivator of several nuclear hormone receptors and also of non-nuclear receptor systems. Its recruitment by the transcriptional machinery induces protein methylation, leading to chromatin remodelling and gene activation. CARM128–507 and two structural states of CARM1140–480 were expressed, purified and crystallized. Crystals of CARM128–507 belong to space group P6222, with unit-cell parameters a = b = 136.0, c = 125.3 Å; they diffract to beyond 2.5 Å resolution using synchrotron radiation and contain one monomer in the asymmetric unit. The structure of CARM128–507 was solved by multiple isomorphous replacement and anomalous scattering methods. Crystals of apo CARM1140–480 belong to space group I222, with unit-cell parameters a = 74.6, b = 99.0, c = 207.4 Å; they diffract to beyond 2.7 Å resolution and contain two monomers in the asymmetric unit. Crystals of CARM1140–480 in complex with S-­adenosyl-l-homocysteine belong to space P21212, with unit-cell parameters a = 74.6, b = 98.65, c = 206.08 Å; they diffract to beyond 2.6 Å resolution and contain four monomers in the asymmetric unit. The structures of apo and holo CARM1140–480 were solved by molecular-replacement techniques from the structure of CARM128–507. PMID:17401209

  19. Steroid receptor coactivator-1 mediates letrozole induced downregulation of postsynaptic protein PSD-95 in the hippocampus of adult female rats.

    PubMed

    Liu, Mengying; Huangfu, Xuhong; Zhao, Yangang; Zhang, Dongmei; Zhang, Jiqiang

    2015-11-01

    Hippocampus local estrogen which is converted from androgen that catalyzed by aromatase has been shown to play important roles in the regulation of learning and memory as well as cognition through action on synaptic plasticity, but the underlying mechanisms are poorly understood. Steroid receptor coactivator-1 (SRC-1) is one of the coactivators of steroid nuclear receptors; it is widely distributed in brain areas that related to learning and memory, reproductive regulation, sensory and motor information integration. Previous studies have revealed high levels of SRC-1 immunoreactivities in the hippocampus; it is closely related to the levels of synaptic proteins such as PSD-95 under normal development or gonadectomy, but its exact roles in the regulation of these proteins remains unclear. In this study, we used aromatase inhibitor letrozole in vivo and SRC-1 RNA interference in vitro to investigate whether SRC-1 mediated endogenous estrogen regulation of hippocampal PSD-95. The results revealed that letrozole injection synchronously decreased hippocampal SRC-1 and PSD-95 in a dose-dependant manner. Furthermore, when SRC-1 specific shRNA pool was applied to block the expression of SRC-1 in the primary hippocampal neuron culture, both immunocytochemistry and Western blot revealed that levels of PSD-95 were also decreased significantly. Taking together, these results provided the first evidence that SRC-1 mediated endogenous estrogen regulation of hippocampal synaptic plasticity by targeting the expression of synaptic protein PSD-95. Additionally, since letrozole is frequently used to treat estrogen-sensitive breast cancer, the above results also indicate its potential side effects in clinical administration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. TBLR1 as an androgen receptor (AR) coactivator selectively activates AR target genes to inhibit prostate cancer growth.

    PubMed

    Daniels, Garrett; Li, Yirong; Gellert, Lan Lin; Zhou, Albert; Melamed, Jonathan; Wu, Xinyu; Zhang, Xinming; Zhang, David; Meruelo, Daniel; Logan, Susan K; Basch, Ross; Lee, Peng

    2014-02-01

    Androgen receptor (AR), a steroid hormone receptor, is critical for prostate cancer growth. However, activation of AR by androgens can also lead to growth suppression and differentiation. Transcriptional cofactors play an important role in this switch between proliferative and anti-proliferative AR target gene programs. Transducin β-like-related protein 1 (TBLR1), a core component of the nuclear receptor corepressor complex, shows both corepressor and coactivator activities on nuclear receptors, but little is known about its effects on AR and prostate cancer. We characterized TBLR1 as a coactivator of AR in prostate cancer cells and determined that the activation is dependent on both phosphorylation and 19S proteosome. We showed that TBLR1 physically interacts with AR and directly occupies the androgen-response elements of the affected AR target genes in an androgen-dependent manner. TBLR1 is primarily localized in the nucleus in benign prostate cells and nuclear expression is significantly reduced in prostate cancer cells in culture. Similarly, in human tumor samples, the expression of TBLR1 in the nucleus is significantly reduced in the malignant glands compared with the surrounding benign prostatic glands (P<0.005). Stable ectopic expression of nuclear TBLR1 leads to androgen-dependent growth suppression of prostate cancer cells in vitro and in vivo by selective activation of androgen-regulated genes associated with differentiation (e.g. KRT18) and growth suppression (e.g. NKX3-1), but not cell proliferation of the prostate cancer. Understanding the molecular switches involved in the transition from AR-dependent growth promotion to AR-dependent growth suppression will lead to more successful treatments for prostate cancer.

  1. Synthesis and evaluation of sulfonylnitrophenylthiazoles (SNPT's) as thyroid hormone receptor-coactivator interaction inhibitors

    PubMed Central

    Hwang, Jong Yeon; Attia, Ramy R.; Zhu, Fangyi; Yang, Lei; Lemoff, Andrew; Jeffries, Cynthia; Connelly, Michele C.; Guy, R. Kiplin

    2012-01-01

    We previously identified a series of methylsulfonylnitrobenzoates (MSNB's) that block the interaction of the thyroid hormone receptor with its coactivators. MSNB's inhibits coactivator binding through irreversibly modifying cysteine 298 of thyroid hormone receptor (TR). Although MSNB's have better pharmacological features than our first generation inhibitors (β-aminoketones) they contain a potentially unstable ester linkage. Here we report the bioisosteric replacement of the ester linkage with a thiazole moiety, yielding sulfonylnitrophenylthiazoles (SNPT's). An array of SNPT's representing optimal side chains from the MSNB series was constructed using parallel chemistry and evaluated to test their antagonism of the TR-coactivator interaction. Selected active compounds were evaluated in secondary confirmatory assays including regulation of thyroid response element driven transcription in reporter constructs and native genes. In addition the selected SNPT's shown to be selective for TR relative to other nuclear hormone receptor (NR). PMID:22324546

  2. Targeting AR Variant-Coactivator Interactions to Exploit Prostate Cancer Vulnerabilities.

    PubMed

    Magani, Fiorella; Peacock, Stephanie O; Rice, Meghan A; Martinez, Maria J; Greene, Ann M; Magani, Pablo S; Lyles, Rolando; Weitz, Jonathan R; Burnstein, Kerry L

    2017-08-15

    Castration-resistant prostate cancer (CRPC) progresses rapidly and is incurable. Constitutively active androgen receptor splice variants (AR-Vs) represent a well-established mechanism of therapeutic resistance and disease progression. These variants lack the AR ligand-binding domain and, as such, are not inhibited by androgen deprivation therapy (ADT), which is the standard systemic approach for advanced prostate cancer. Signaling by AR-Vs, including the clinically relevant AR-V7, is augmented by Vav3, an established AR coactivator in CRPC. Using mutational and biochemical studies, we demonstrated that the Vav3 Diffuse B-cell lymphoma homology (DH) domain interacted with the N-terminal region of AR-V7 (and full length AR). Expression of the Vav3 DH domain disrupted Vav3 interaction with and enhancement of AR-V7 activity. The Vav3 DH domain also disrupted AR-V7 interaction with other AR coactivators: Src1 and Vav2, which are overexpressed in PC. This Vav3 domain was used in proof-of-concept studies to evaluate the effects of disrupting the interaction between AR-V7 and its coactivators on CRPC cells. This disruption decreased CRPC cell proliferation and anchorage-independent growth, caused increased apoptosis, decreased migration, and resulted in the acquisition of morphological changes associated with a less aggressive phenotype. While disrupting the interaction between FL-AR and its coactivators decreased N-C terminal interaction, disrupting the interaction of AR-V7 with its coactivators decreased AR-V7 nuclear levels.Implications: This study demonstrates the potential therapeutic utility of inhibiting constitutively active AR-V signaling by disrupting coactivator binding. Such an approach is significant, as AR-Vs are emerging as important drivers of CRPC that are particularly recalcitrant to current therapies. Mol Cancer Res; 1-12. ©2017 AACR. ©2017 American Association for Cancer Research.

  3. Characteristics of diffuse muscular coactivation (DMC) in persons with fibromyalgia -- part 2.

    PubMed

    Donaldson, C C S; MacInnis, A L; Snelling, L S; Sella, G E; Mueller, H H

    2002-01-01

    This study examined the electrical characteristics (Root Mean Square -- RMS and median frequency) of Diffuse Muscular Coactivation (DMC) associated with the tender points of fibromyalgia. DMC is defined as an increase from resting levels (tonus) in the electrical activity of any muscle during a movement which does not involve that muscle and is not part of the agonist -- antagonist unit. The results show an increase in RMS in fibromyalgia sufferers as compared to controls. Coactivation was stronger proximal to the neck and decreased in intensity as the area recorded moved distally. Median frequency changed over time but not significantly between groups. Possible neurological mechanisms are discussed.

  4. Coaching Younger Practitioners and Students Using Components of the Co-Active Coaching Model

    PubMed Central

    2010-01-01

    Coaching is used to improve performance, achieve preset goals and obtain desired results. Several coaching models have been used in health professions for leadership and professional development. This article describes some components of Co-Active Coaching® that can be applied while coaching pharmacy students and younger practitioners. Co-Active Coaching requires the coach to use a broad range of communication skills, including listening, asking powerful questions, making insightful comments, offering encouragement, and giving sincere praise. The characteristics of the ideal candidate for coaching and the value of coaching are also discussed. PMID:20498744

  5. The Structure of A Biologically Active Estrogen Receptor-Coactivator Complex on DNA

    PubMed Central

    Yi, Ping; Wang, Zhao; Feng, Qin; Pintilie, Grigore D.; Foulds, Charles E.; Lanz, Rainer B.; Ludtke, Steven J.; Schmid, Michael F.; Chiu, Wah; O’Malley, Bert W.

    2015-01-01

    SUMMARY Estrogen receptor (ER) is a transcription factor critical for development, reproduction, metabolism and cancer. ER function hinges on its ability to recruit primary and secondary coactivators, yet structural information on the full-length receptor-coactivator complex to complement pre-existing and sometimes controversial biochemical information is lacking. Here we use cryo-EM to determine the quaternary structure of an active complex of DNA-bound ERα, steroid receptor coactivator 3 (SRC-3) and a secondary coactivator (p300). Our structural model suggests the following assembly mechanism for the complex: each of the two ligand-bound ERα monomers independently recruits one SRC-3 protein via the transactivation domain of ERα; the two SRC-3s in turn bind to different regions of one p300 protein through multiple contacts. We also present structural evidence for the location of activation function 1 (AF-1) in a full-length nuclear receptor, which supports a role for AF-1 in SRC-3 recruitment. PMID:25728767

  6. Resisting the Marginalization of Science in an Urban School: Coactivating Social, Cultural, Material, and Strategic Resources

    ERIC Educational Resources Information Center

    Rivera Maulucci, Maria S.

    2010-01-01

    This study describes the resources and strategies middle school teachers, urban fellows, and a district science staff developer coactivated to resist the marginalization of science in a high-poverty, low-performing urban school. Through critical narrative inquiry, I document factors that marginalized science in three teachers' classrooms. The…

  7. The Race that Precedes Coactivation: Development of Multisensory Facilitation in Children

    ERIC Educational Resources Information Center

    Barutchu, Ayla; Crewther, David P.; Crewther, Sheila G.

    2009-01-01

    Rationale: The facilitating effect of multisensory integration on motor responses in adults is much larger than predicted by race-models and is in accordance with the idea of coactivation. However, the development of multisensory facilitation of endogenously driven motor processes and its relationship to the development of complex cognitive skills…

  8. Effects of Response Task and Accessory Stimuli on Redundancy Gain: Tests of the Hemispheric Coactivation Model

    ERIC Educational Resources Information Center

    Miller, Jeff; Van Nes, Fenna

    2007-01-01

    Two experiments tested predictions of the hemispheric coactivation model for redundancy gain (J. O. Miller, 2004). Simple reaction time was measured in divided attention tasks with visual stimuli presented to the left or right of fixation or redundantly to both sides. Experiment 1 tested the prediction that redundancy gain--the decrease in…

  9. SRC-2 is an essential coactivator for orchastrating metabolism and circadian rhythm

    USDA-ARS?s Scientific Manuscript database

    Synchrony of the mammalian circadian clock is achieved by complex transcriptional and translational feedback loops centered on the BMAL1:CLOCK heterodimer. Modulation of circadian feedback loops is essential for maintaining rhythmicity, yet the role of transcriptional coactivators in driving BMAL1:C...

  10. Involvement of Novel Multifunctional Steroid Hormone Receptor Coactivator, E6-Associated Protein, in Prostate Gland Tumorigenesis

    DTIC Science & Technology

    2008-01-01

    Angelman syndrome-associated protein, E6-AP, is a coactivator for the nuclear hormone receptor superfamily. Mol Cell Biol 19:1182-9. 26. Hsiao PW, Chang C...Albrecht U, Atkins CM, Noebels JL, Eichele G, Sweatt JD, Beaudet AL 1998 Mutation of the Angelman ubiquitin ligase in mice causes increased cytoplasmic

  11. Superficial shoulder muscle co-activations during lifting tasks: Influence of lifting height, weight and phase.

    PubMed

    Blache, Y; Dal Maso, F; Desmoulins, L; Plamondon, A; Begon, M

    2015-04-01

    This study aimed to assess the level of co-activation of the superficial shoulder muscles during lifting movement. Boxes containing three different loads (6, 12, and 18 kg) were lifted by fourteen subjects from the waist to shoulder or eye level. The 3D kinematics and electromyograms of the three deltoids, latissimus dorsi and pectoralis major were recorded. A musculoskeletal model was used to determine direction of the moment arm of these muscles. Finally an index of muscle co-activation named the muscle focus was used to evaluate the effects of lifting height, weight lifted and phase (pulling, lifting and dropping phases) on superficial shoulder muscle coactivation. The muscle focus was lower (more co-contraction) during the dropping phase compared to the two other phases (-13%, p<0.001). This was explained by greater muscle activations and by a change in the direction of the muscle moment arm as a function of glenohumeral joint position. Consequently, the function of the shoulder superficial muscles varied with respect to the glenohumeral joint position. To increase the superficial muscle coactivation during the dropping phase may be a solution to increase glenohumeral joint stiffness.

  12. Effects of Response Task and Accessory Stimuli on Redundancy Gain: Tests of the Hemispheric Coactivation Model

    ERIC Educational Resources Information Center

    Miller, Jeff; Van Nes, Fenna

    2007-01-01

    Two experiments tested predictions of the hemispheric coactivation model for redundancy gain (J. O. Miller, 2004). Simple reaction time was measured in divided attention tasks with visual stimuli presented to the left or right of fixation or redundantly to both sides. Experiment 1 tested the prediction that redundancy gain--the decrease in…

  13. Co-Activation of Cultured Human Natural Killer Cells: Enhanced Function and Decreased Inhibition.

    PubMed

    Urlaub, Doris; Bhat, Rauf; Messmer, Birgitta; Watzl, Carsten

    2016-01-01

    Natural killer (NK) cells are important immune effector cells that protect the organism against viral infections and cancer. The cytotoxic activity of NK cells is induced by the engagement of a number of different activating surface receptors and controlled by inhibitory receptors to ensure self-tolerance. Resting NK cells need to be co-activated by involvement of at least two distinct activating receptors in order to induce their functional activity. However, in cultured NK cells, which have been expanded in cytokines such as interleukin (IL)-2, the engagement of a single activating receptor may be sufficient to induce their function. Data demonstrated that also cultured NK cells may be co-activated by involvement of certain combinations of activating receptors. This co-activation results in enhanced activation of Vav-1 and ERK signaling pathways and produces greater degranulation. In addition to enhanced functionality, co-activation makes NK cells more resistant to the effect of inhibitory receptors, thereby inducing more potent and efficient NK cell responses.

  14. Transcriptional regulation through Mediator-like coactivators in yeast and metazoan cells.

    PubMed

    Malik, S; Roeder, R G

    2000-06-01

    A novel multiprotein complex has recently been identified as a coactivator for transcriptional control of protein-encoding genes by RNA polymerase II in higher eukaryotic cells. This complex is evolutionarily related to the Mediator complex from yeast and, on the basis of its structural and functional characteristics, promises to be a key target of diverse regulatory circuits.

  15. Blocking Estrogen Signaling After the Hormone: Pyrimidine-Core Inhibitors of Estrogen Receptor-Coactivator Binding

    PubMed Central

    Parent, Alexander A.; Gunther, Jillian R.; Katzenellenbogen, John A.

    2009-01-01

    As an alternative approach to blocking estrogen action, we have developed small molecules that directly disrupt the key estrogen receptor (ER)/coactivator interaction necessary for gene activation. The more direct, protein-protein nature of this disruption might be effective even in hormone-refractory breast cancer. We have synthesized a pyrimidine-core library of moderate size, members of which act as α-helix mimics to block ERα/coactivator interaction. Structure- activity relationships have been explored with various C, N, O and S-substituents on the pyrimidine core. Time-resolved fluorescence resonance energy transfer and cell-based reporter gene assays show that the most active members inhibit the ERα/steroid receptor coactivator interaction with Ki’s in the low micromolar range. Through these studies, we have obtained a refined pharmacophore model for activity in this pyrimidine series. Furthermore, the favorable activities of several of these compounds support the feasibility that this coactivator binding inhibition mechanism for blocking estrogen action might provide a potential alternative approach to endocrine therapy. PMID:18785725

  16. Dissection of the LXXLL Nuclear Receptor-Coactivator Interaction Motif Using Combinatorial Peptide Libraries: Discovery of Peptide Antagonists of Estrogen Receptors α and β

    PubMed Central

    Chang, Ching-yi; Norris, John D.; Grøn, Hanne; Paige, Lisa A.; Hamilton, Paul T.; Kenan, Daniel J.; Fowlkes, Dana; McDonnell, Donald P.

    1999-01-01

    Recruitment of transcriptional coactivators following ligand activation is a critical step in nuclear receptor-mediated target gene expression. Upon binding an agonist, the receptor undergoes a conformational change which facilitates the formation of a specific coactivator binding pocket within the carboxyl terminus of the receptor. This permits the α-helical LXXLL motif within some coactivators to interact with the nuclear receptors. Until recently, the LXXLL motif was thought to function solely as a docking module; however, it now appears that sequences flanking the core motif may play a role in determining receptor selectivity. To address this issue, we used a combinatorial phage display approach to evaluate the role of flanking sequences in influencing these interactions. We sampled more than 108 variations of the core LXXLL motif with estradiol-activated estrogen receptor alpha (ERα) as a target and found three different classes of peptides. All of these peptides interacted with ERα in an agonist-dependent manner and disrupted ERα-mediated transcriptional activity when introduced into target cells. Using a series of ERα-mutants, we found that these three classes of peptides showed different interaction patterns from each other, suggesting that not all LXXLL motifs are the same and that receptor binding selectivity can be achieved by altering sequences flanking the LXXLL core motif. Most notable in this regard was the discovery of a peptide which, when overexpressed in cells, selectively disrupted ERβ- but not ERα-mediated reporter gene expression. This novel ERβ-specific antagonist may be useful in identifying and characterizing the ERβ-regulated process in estradiol-responsive cells. In conclusion, using a combinatorial approach to define cofactor-receptor interactions, we have clearly been able to demonstrate that not all LXXLL motifs are functionally equivalent, a finding which suggests that it may be possible to target receptor-LXXLL interactions

  17. A key role of PGC-1α transcriptional coactivator in production of VEGF by a novel angiogenic agent COA-Cl in cultured human fibroblasts.

    PubMed

    Igarashi, Junsuke; Okamoto, Ryuji; Yamashita, Tetsuo; Hashimoto, Takeshi; Karita, Sakiko; Nakai, Kozo; Kubota, Yasuo; Takata, Maki; Yamaguchi, Fuminori; Tokuda, Masaaki; Sakakibara, Norikazu; Tsukamoto, Ikuko; Konishi, Ryoji; Hirano, Katsuya

    2016-03-01

    We previously demonstrated a potent angiogenic effect of a newly developed adenosine-like agent namedCOA-Cl.COA-Cl exerted tube forming activity in human umbilical vein endothelial cells in the presence of normal human dermal fibroblasts (NHDF). We therefore explored whether and howCOA-Cl modulates gene expression and protein secretion ofVEGF, a master regulator of angiogenesis, inNHDFRT-PCRandELISArevealed thatCOA-Cl upregulatedVEGF mRNAexpression and protein secretion inNHDFHIF1α(hypoxia-inducible factor 1α), a transcription factor, andPGC-1α(peroxisome proliferator-activated receptor-γcoactivator-1α), a transcriptional coactivator, are known to positively regulate theVEGFgene. Immunoblot andRT-PCRanalyses revealed thatCOA-Cl markedly upregulated the expression ofPGC-1αprotein andmRNACOA-Cl had no effect on the expression ofHIF1αprotein andmRNAin both hypoxia and normoxia. SilencingPGC-1αgene, but notHIF1αgene, by small interferingRNAattenuated the ability ofCOA-Cl to promoteVEGFsecretion. When an N-terminal fragment ofPGC-1αwas cotransfected with its partner transcription factorERRα(estrogen-related receptor-α) inCOS-7 cells,COA-Cl upregulated the expression of the endogenousVEGF mRNA However,COA-Cl had no effect on the expression ofVEGF, whenHIF1αwas transfected.COA-Cl inducesVEGFgene expression and protein secretion in fibroblasts. The transcriptional coactivatorPGC-1α, in concert withERRα, plays a key role in theCOA-Cl-inducedVEGFproduction.COA-Cl-induced activation ofPGC-1α-ERRα-VEGFpathway has a potential as a novel means for therapeutic angiogenesis.

  18. A muscle-specific knockout implicates nuclear receptor coactivator MED1 in the regulation of glucose and energy metabolism.

    PubMed

    Chen, Wei; Zhang, Xiaoting; Birsoy, Kivanc; Roeder, Robert G

    2010-06-01

    As conventional transcriptional factors that are activated in diverse signaling pathways, nuclear receptors play important roles in many physiological processes that include energy homeostasis. The MED1 subunit of the Mediator coactivator complex plays a broad role in nuclear receptor-mediated transcription by anchoring the Mediator complex to diverse promoter-bound nuclear receptors. Given the significant role of skeletal muscle, in part through the action of nuclear receptors, in glucose and fatty acid metabolism, we generated skeletal muscle-specific Med1 knockout mice. Importantly, these mice show enhanced insulin sensitivity and improved glucose tolerance as well as resistance to high-fat diet-induced obesity. Furthermore, the white muscle of these mice exhibits increased mitochondrial density and expression of genes specific to type I and type IIA fibers, indicating a fast-to-slow fiber switch, as well as markedly increased expression of the brown adipose tissue-specific UCP-1 and Cidea genes that are involved in respiratory uncoupling. These dramatic results implicate MED1 as a powerful suppressor in skeletal muscle of genetic programs implicated in energy expenditure and raise the significant possibility of therapeutical approaches for metabolic syndromes and muscle diseases through modulation of MED1-nuclear receptor interactions.

  19. Novel interaction between nuclear co-activator CBP and the CDK5 activator binding protein - C53.

    PubMed

    Yin, Xiaolong; Warner, Dennis R; Roberts, Emily A; Pisano, M Michele; Greene, Robert M

    2005-08-01

    cAMP response element-binding protein (CREB)-binding protein (CBP) is a multifunctional transcriptional co-activator that plays important roles in cell proliferation and differentiation. CBP is expressed in murine embryonic orofacial tissue and is developmentally regulated. To identify nuclear factors associating with CBP in developing orofacial tissue, a yeast two-hybrid screen of a cDNA library derived from embryonic orofacial tissue from gestational days 11-13 mouse embryos was conducted. The carboxy terminal region of CBP (including the C/H3 region) was utilized as a bait. C53, a 57 kDa protein known to bind to the p25 activator of cyclin-dependent kinase 5, was identified as a novel binding partner of CBP. The association of C53 with CBP was confirmed in vitro by glutathione S-transferase pull-down assays, and in vivo by co-immunoprecipitation. Reporter assays demonstrated that C53 had little effect on CBP mediated transcriptional activation. These results identify C53 as a novel binding partner for CBP. Recent research on presenilin-loss induced neurodegeneration demonstrated decreased expression of CBP and increased levels of the Cdk5 activator p25, both C53 binding proteins, suggesting that C53 might play a role in regulating neuronal proliferation, migration and/or differentiation in embryonic development.

  20. FLASH interacts with p160 coactivator subtypes and differentially suppresses transcriptional activity of steroid hormone receptors.

    PubMed

    Kino, Tomoshige; Ichijo, Takamasa; Chrousos, George P

    2004-12-01

    We previously reported that tumor necrosis factor alpha receptor- and Fas-associated FLASH interacts with one of the p160 nuclear receptor coactivators, glucocorticoid receptor-interacting protein (GRIP) 1, at its nuclear receptor-binding (NRB) domain, and that inhibits the transcriptional activity of the glucocorticoid receptor (GR) by interfering with association of GR and GRIP1. Here, we further examined the specificity of FLASH suppressive effect and the physical/functional interactions between this protein and two other p160 family subtypes. The suppressive effect of FLASH on GR transactivation was observed in several cell lines and on the chromatin-integrated mouse mammary tumor virus (MMTV) promoter. FLASH strongly interacted with the NRB domain of the thyroid hormone receptor activator molecule (TRAM) 1, a member of the steroid hormone receptor coactivator (SRC) 3/nuclear receptor coactivator (N-CoA) 3 subtypes, as well as with SRC2/N-CoA2 p160 coactivator GRIP1, while its interaction with SRC1a, one of the SRC1/N-CoA1 proteins, was faint in yeast two-hybrid assays. Accordingly, FLASH strongly suppressed TRAM1- and GRIP1-induced enhancement of GR-stimulated transactivation of the MMTV promoter in HCT116 cells, while it did not affect SRC1a-induced potentiation of transcription. Furthermore, FLASH suppressed androgen- and progesterone receptor-induced transcriptional activity, but did not influence estrogen receptor-induced transactivation, possibly due to their preferential use of p160 coactivators in HCT116 and HeLa cells. Thus, FLASH differentially suppresses steroid hormone receptor-induced transcriptional activity by interfering with their association with SRC2/N-CoA2 and SRC3/N-CoA3 but not with SRC1/N-CoA1.

  1. The relationship between external knee moments and muscle co-activation in subjects with medial knee osteoarthritis.

    PubMed

    Selistre, Luiz Fernando Approbato; Mattiello, Stela Márcia; Nakagawa, Theresa Helissa; Gonçalves, Glaucia Helena; Petrella, Marina; Jones, Richard Keith

    2017-04-01

    External knee moments are reliable to measure knee load but it does not take into account muscle activity. Considering that muscle co-activation increases compressive forces at the knee joint, identifying relationships between muscle co-activations and knee joint load would complement the investigation of the knee loading in subjects with knee osteoarthritis. The purpose of this study was to identify relationships between muscle co-activation and external knee moments during walking in subjects with medial knee osteoarthritis. 19 controls (11 males, aged 56.6±5, and BMI 25.2±3.3) and 25 subjects with medial knee osteoarthritis (12 males, aged 57.3±5.3, and BMI 28.2±4) were included in this study. Knee adduction and flexion moments, and co-activation (ratios and sums of quadriceps, hamstring, and gastrocnemius) were assessed during walking and compared between groups. The relationship between knee moments and co-activation was investigated in both groups. Subjects with knee osteoarthritis presented a moderate and strong correlation between co-activation (ratios and sums) and knee moments. Muscle co-activation should be used to measure the contribution of quadriceps, hamstring, and gastrocnemius on knee loading. This information would cooperate to develop a more comprehensive approach of knee loading in this population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Corepressive function of nuclear receptor coactivator 2 in androgen receptor of prostate cancer cells treated with antiandrogen.

    PubMed

    Takeda, Keisuke; Hara, Noboru; Nishiyama, Tsutomu; Tasaki, Masayuki; Ishizaki, Fumio; Tomita, Yoshihiko

    2016-05-25

    Recruitment of cofactors in the interaction of the androgen receptor (AR) and AR ligands plays a critical role in determining androgenic/antiandrogenic effects of the AR ligand on signaling, but the functions of key cofactors, including nuclear receptor coactivator (NCOA), remain poorly understood in prostate cancer cells treated with AR ligands. We examined prostate cancer cell lines LNCaP and VCaP expressing mutated and wild-type ARs, respectively, to clarify the significance of NCOAs in the effect of antiandrogens. Hydroxyflutamide showed antagonistic activity against VCaP and an agonistic effect on LNCaP. Bicalutamide served as an antagonist for both. We analyzed mRNA transcription and protein expression of NCOAs in these cells pretreated with dihydrotestosterone and thereafter treated with the mentioned antiandrogens. Transcriptional silencing of candidate NCOAs and AR was performed using small interfering RNA (siRNA). Cell proliferation was evaluated with MTT assay. LNCaP treated with bicalutamide showed an about four-fold increase in the expression of NCOA2 mRNA compared to those pretreated with dihydrotestosterone alone (P <0.01). In VCaP pretreated with dihydrotestosterone, transcriptions of NCOA2 and NCOA7 were slightly increased with bicalutamide (1.96- and 2.42-fold, respectively) and hydroxyflutamide (1.33-fold in both). With Western blotting, the expression of NCOA2 protein also increased in LNCaP cells treated with bicalutamide compared with that in control cells pretreated with dihydrotestosterone alone. Following silencing with siRNA for NCOA2, PSA levels in media with LNCaP receiving bicalutamide were elevated compared with those in non-silencing controls (101.6 ± 4.2 vs. 87.8 ± 1.4 ng/mL, respectively, P =0.0495). In LNCaP cells treated with dihydrotestosterone and bicalutamide, NCOA2-silencing was associated with a higher proliferation activity compared with non-silencing control and AR-silencing. NCOA2, which has been thought to be

  3. NRC-interacting factor 1 is a novel cotransducer that interacts with and regulates the activity of the nuclear hormone receptor coactivator NRC.

    PubMed

    Mahajan, Muktar A; Murray, Audrey; Samuels, Herbert H

    2002-10-01

    We previously reported the cloning and characterization of a novel nuclear hormone receptor transcriptional coactivator, which we refer to as NRC. NRC is a 2,063-amino-acid nuclear protein which contains a potent N-terminal activation domain and several C-terminal modules which interact with CBP and ligand-bound nuclear hormone receptors as well as c-Fos and c-Jun. In this study we sought to clone and identify novel factors that interact with NRC to modulate its transcriptional activity. Here we describe the cloning and characterization of a novel protein we refer to as NIF-1 (NRC-interacting factor 1). NIF-1 was cloned from rat pituitary and human cell lines and was found to interact in vivo and in vitro with NRC. NIF-1 is a 1,342-amino-acid nuclear protein containing a number of conserved domains, including six Cys-2/His-2 zinc fingers, an N-terminal stretch of acidic amino acids, and a C-terminal leucine zipper-like motif. Zinc fingers 1 to 3 are potential DNA-binding BED finger domains recently proposed to play a role in altering local chromatin architecture. We mapped the interaction domains of NRC and NIF-1. Although NIF-1 does not directly interact with nuclear receptors, it markedly enhances ligand-dependent transcriptional activation by nuclear hormone receptors in vivo as well as activation by c-Fos and c-Jun. These results, and the finding that NIF-1 interacts with NRC in vivo, suggest that NIF-1 functions to regulate transcriptional activation through NRC. We suggest that NIF-1, and factors which associate with coactivators but not receptors, be referred to as cotransducers, which act in vivo either as part of a coactivator complex or downstream of a coactivator complex to modulate transcriptional activity. Our findings suggest that NIF-1 may be a functional component of an NRC complex and acts as a regulator or cotransducer of NRC function.

  4. Ligand-dependent interactions of the Ah receptor with coactivators in a mammalian two-hybrid assay

    SciTech Connect

    Zhang Shu; Rowlands, Craig; Safe, Stephen

    2008-03-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a high affinity ligand for the aryl hydrocarbon receptor (AhR). In this study, we investigated structure-dependent differences in activation of the AhR by a series of halogenated aromatic hydrocarbons. TCDD, 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 3,3',4,4',5-pentachlorobiphenyl (PCB126) induced CYP1A1-dependent activities in HEK293 human embryonic kidney, Panc1 pancreatic cancer, and Hepa1c1c7 mouse hepatoma cell lines. There was a structure-dependent difference in the efficacy of TCDF and PCB126 in HEK293 and Panc1 cells since induced CYP1A1 mRNA levels were lower than observed for the other congeners. A mammalian two-hybrid assay in cells transfected with GAL4-coactivator and AhR-VP16 chimeras was used to investigate structure-dependent interactions of these chimeras in Panc1, HEK293, and Hepa1c1c7 cells. The reporter construct pGAL4-luc contains five tandem GAL4 response elements linked to the luciferase gene and the GAL4-coactivator chimeras express several coactivators including steroid receptor coactivator 1 (SRC-1), SRC-2 and SRC-3, the mediator coactivator TRAP220, coactivator associated arginine methyl transferase 1 (CARM-1), and peroxisome proliferator-activated receptor {gamma} coactivator 1 (PGC-1). Results of the mammalian two-hybrid studies clearly demonstrate that activation of pGAL4-luc in cells transfected with VP-AhR and GAL4-coactivator chimeras is dependent on the structure of the HAH congener, cell context, and coactivator, suggesting that the prototypical HAH congeners used in this study exhibit selective AhR modulator activity.

  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. Macrophage PPAR gamma Co-activator-1 alpha participates in repressing foam cell formation and atherosclerosis in response to conjugated linoleic acid

    PubMed Central

    McCarthy, Cathal; Lieggi, Nora T; Barry, Denis; Mooney, Declan; de Gaetano, Monica; James, William G; McClelland, Sarah; Barry, Mary C; Escoubet-Lozach, Laure; Li, Andrew C; Glass, Christopher K; Fitzgerald, Desmond J; Belton, Orina

    2013-01-01

    Conjugated linoleic acid (CLA) has the unique property of inducing regression of pre-established murine atherosclerosis. Understanding the mechanism(s) involved may help identify endogenous pathways that reverse human atherosclerosis. Here, we provide evidence that CLA inhibits foam cell formation via regulation of the nuclear receptor coactivator, peroxisome proliferator-activated receptor (PPAR)-γ coactivator (PGC)-1α, and that macrophage PGC-1α plays a role in atheroprotection in vivo. PGC-1α was identified as a hub gene within a cluster in the aorta of the apoE−/− mouse in the CLA-induced regression model. PGC-1α was localized to macrophage/foam cells in the murine aorta where its expression was increased during CLA-induced regression. PGC-1α expression was also detected in macrophages in human atherosclerosis and was inversely linked to disease progression in patients with the disease. Deletion of PGC-1α in bone marrow derived macrophages promoted, whilst over expression of the gene inhibited foam cell formation. Importantly, macrophage specific deletion of PGC-1α accelerated atherosclerosis in the LDLR−/− mouse in vivo. These novel data support a functional role for PGC-1α in atheroprotection. PMID:23964012

  7. Regulation of tumor necrosis factor alpha gene expression by mycobacteria involves the assembly of a unique enhanceosome dependent on the coactivator proteins CBP/p300.

    PubMed

    Barthel, Robert; Tsytsykova, Alla V; Barczak, Amy K; Tsai, Eunice Y; Dascher, Christopher C; Brenner, Michael B; Goldfeld, Anne E

    2003-01-01

    Tumor necrosis factor alpha (TNF-alpha) plays an important role in host containment of infection by Mycobacterium tuberculosis, one of the leading causes of death by an infectious agent globally. Using the pathogenic M. tuberculosis strain H37Rv, we present evidence that upon stimulation of monocytic cells by M. tuberculosis a unique TNF-alpha enhanceosome is formed, and it is distinct from the TNF-alpha enhanceosome that forms in T cells stimulated by antigen engagement or virus infection. A distinct set of activators including ATF-2, c-jun, Ets, Sp1, Egr-1 and the coactivator proteins CBP/p300 are recruited to the TNF-alpha promoter after stimulation with M. tuberculosis. Furthermore, the formation of this enhanceosome is dependent on inducer-specific helical phasing relationships between transcription factor binding sites. We also show that the transcriptional activity of CBP/p300 is potentiated by mycobacterial stimulation of monocytes. The identification of TNF-alpha regulatory elements and coactivators involved in M. tuberculosis-stimulated gene expression thus provides potential selective molecular targets in the modulation of TNF-alpha gene expression in the setting of mycobacterial infection.

  8. YAP/TEAD Co-Activator Regulated Pluripotency and Chemoresistance in Ovarian Cancer Initiated Cells

    PubMed Central

    Yu, Chao; Chang, Ting; Fan, Heng-Yu

    2014-01-01

    Recent evidence suggests that some solid tumors, including ovarian cancer, contain distinct populations of stem cells that are responsible for tumor initiation, growth, chemo-resistance, and recurrence. The Hippo pathway has attracted considerable attention and some investigators have focused on YAP functions for maintaining stemness and cell differentiation. In this study, we successfully isolated the ovarian cancer initiating cells (OCICs) and demonstrated YAP promoted self-renewal of ovarian cancer initiated cell (OCIC) through its downstream co-activator TEAD. YAP and TEAD families were required for maintaining the expression of specific genes that may be involved in OCICs' stemness and chemoresistance. Taken together, our data first indicate that YAP/TEAD co-activator regulated ovarian cancer initiated cell pluripotency and chemo-resistance. It proposed a new mechanism on the drug resistance in cancer stem cell that Hippo-YAP signal pathway might serve as therapeutic targets for ovarian cancer treatment in clinical. PMID:25369529

  9. YAP/TEAD co-activator regulated pluripotency and chemoresistance in ovarian cancer initiated cells.

    PubMed

    Xia, Yan; Zhang, Yin-Li; Yu, Chao; Chang, Ting; Fan, Heng-Yu

    2014-01-01

    Recent evidence suggests that some solid tumors, including ovarian cancer, contain distinct populations of stem cells that are responsible for tumor initiation, growth, chemo-resistance, and recurrence. The Hippo pathway has attracted considerable attention and some investigators have focused on YAP functions for maintaining stemness and cell differentiation. In this study, we successfully isolated the ovarian cancer initiating cells (OCICs) and demonstrated YAP promoted self-renewal of ovarian cancer initiated cell (OCIC) through its downstream co-activator TEAD. YAP and TEAD families were required for maintaining the expression of specific genes that may be involved in OCICs' stemness and chemoresistance. Taken together, our data first indicate that YAP/TEAD co-activator regulated ovarian cancer initiated cell pluripotency and chemo-resistance. It proposed a new mechanism on the drug resistance in cancer stem cell that Hippo-YAP signal pathway might serve as therapeutic targets for ovarian cancer treatment in clinical.

  10. Coactivation of GR and NFKB alters the repertoire of their binding sites and target genes

    PubMed Central

    Rao, Nagesha A.S.; McCalman, Melysia T.; Moulos, Panagiotis; Francoijs, Kees-Jan; Chatziioannou, Aristotelis; Kolisis, Fragiskos N.; Alexis, Michael N.; Mitsiou, Dimitra J.; Stunnenberg, Hendrik G.

    2011-01-01

    Glucocorticoid receptor (GR) exerts anti-inflammatory action in part by antagonizing proinflammatory transcription factors such as the nuclear factor kappa-b (NFKB). Here, we assess the crosstalk of activated GR and RELA (p65, major NFKB component) by global identification of their binding sites and target genes. We show that coactivation of GR and p65 alters the repertoire of regulated genes and results in their association with novel sites in a mutually dependent manner. These novel sites predominantly cluster with p65 target genes that are antagonized by activated GR and vice versa. Our data show that coactivation of GR and NFKB alters signaling pathways that are regulated by each factor separately and provide insight into the networks underlying the GR and NFKB crosstalk. PMID:21750107

  11. Coactivation of GR and NFKB alters the repertoire of their binding sites and target genes.

    PubMed

    Rao, Nagesha A S; McCalman, Melysia T; Moulos, Panagiotis; Francoijs, Kees-Jan; Chatziioannou, Aristotelis; Kolisis, Fragiskos N; Alexis, Michael N; Mitsiou, Dimitra J; Stunnenberg, Hendrik G

    2011-09-01

    Glucocorticoid receptor (GR) exerts anti-inflammatory action in part by antagonizing proinflammatory transcription factors such as the nuclear factor kappa-b (NFKB). Here, we assess the crosstalk of activated GR and RELA (p65, major NFKB component) by global identification of their binding sites and target genes. We show that coactivation of GR and p65 alters the repertoire of regulated genes and results in their association with novel sites in a mutually dependent manner. These novel sites predominantly cluster with p65 target genes that are antagonized by activated GR and vice versa. Our data show that coactivation of GR and NFKB alters signaling pathways that are regulated by each factor separately and provide insight into the networks underlying the GR and NFKB crosstalk.

  12. Listening to Puns Elicits the Co-Activation of Alternative Homophone Meanings during Language Production

    PubMed Central

    Rose, Sebastian Benjamin; Spalek, Katharina; Rahman, Rasha Abdel

    2015-01-01

    Recent evidence suggests that lexical-semantic activation spread during language production can be dynamically shaped by contextual factors. In this study we investigated whether semantic processing modes can also affect lexical-semantic activation during word production. Specifically, we tested whether the processing of linguistic ambiguities, presented in the form of puns, has an influence on the co-activation of unrelated meanings of homophones in a subsequent language production task. In a picture-word interference paradigm with word distractors that were semantically related or unrelated to the non-depicted meanings of homophones we found facilitation induced by related words only when participants listened to puns before object naming, but not when they heard jokes with unambiguous linguistic stimuli. This finding suggests that a semantic processing mode of ambiguity perception can induce the co-activation of alternative homophone meanings during speech planning. PMID:26114942

  13. Neural co-activation as a yardstick of implicit motor learning and the propensity for conscious control of movement.

    PubMed

    Zhu, F F; Poolton, J M; Wilson, M R; Maxwell, J P; Masters, R S W

    2011-04-01

    Two studies examined EEG co-activation (coherence) between the verbal-analytical (T3) and motor planning (Fz) regions during a golf putting task. In Study 1, participants with a strong propensity to consciously monitor and control their movements, determined psychometrically by high scores on a movement specific Reinvestment Scale, displayed more alpha2 T3-Fz co-activation than participants with a weak propensity. In Study 2, participants who practiced a golf putting task implicitly (via an errorless learning protocol) displayed less alpha2 T3-Fz co-activation than those who practiced explicitly (by errorful learning). In addition, explicit but not implicit motor learners displayed more T3-Fz co-activation during golf putting under pressure, implying that verbal-analytical processing of putting movements increased under pressure. These findings provide neuropsychological evidence that supports claims that implicit motor learning can be used to limit movement specific reinvestment.

  14. The RXR{alpha} C-terminus T462 is a NMR sensor for coactivator peptide binding

    SciTech Connect

    Lu Jianyun Chen Minghe; DeKoster, Gregory T.; Cistola, David P.; Li, Ellen

    2008-02-22

    The C-terminal activation function-2 (AF-2) helix plays a crucial role in retinoid X receptor alpha (RXR{alpha})-mediated gene expression. Here, we report a nuclear magnetic resonance (NMR) study of the RXR{alpha} ligand-binding domain complexed with 9-cis-retinoic acid and a glucocorticoid receptor-interacting protein 1 peptide. The AF-2 helix and most of the C-terminal residues were undetectable due to a severe line-broadening effect. Due to its outstanding signal-to-noise ratio, the C-terminus residue, threonine 462 (T462) exhibited two distinct crosspeaks during peptide titration, suggesting that peptide binding was in a slow exchange regime on the chemical shift timescale. Consistently, the K{sub d} derived from T462 intensity decay agreed with that derived from isothermal titration calorimetry. Furthermore, the exchange contribution to the {sup 15}N transverse relaxation rate was measurable in either T462 or the bound peptide. These results suggest that T462 is a sensor for coactivator binding and is a potential probe for AF-2 helix mobility.

  15. Inhibition of CCAR1, a Coactivator of β-Catenin, Suppresses the Proliferation and Migration of Gastric Cancer Cells

    PubMed Central

    Chang, Te-Sheng; Wei, Kuo-Liang; Lu, Chung-Kuang; Chen, Yi-Hsing; Cheng, Ying-Tung; Tung, Shui-Yi; Wu, Cheng-Shyong; Chiang, Ming-Ko

    2017-01-01

    The aberrant activation of Wnt signaling has been implicated in a variety of human cancers, including gastric cancer. Given the current hypothesis that cancer arises from cancer stem cells (CSCs), targeting the critical signaling pathways that support CSC self-renewal appears to be a useful approach for cancer therapy. Cell cycle and apoptosis regulator 1 (CCAR1) is a transcriptional coactivator which has been shown to be a component of Wnt/β-catenin signaling, and which plays an important role in transcriptional regulation by β-catenin. However, the function and clinical significance of CCAR1 in gastric cancer have not been elucidated. Here, we show that elevated CCAR1 nuclear expression correlates with the occurrence of gastric cancer. In addition, RNAi-mediated CCAR1 reduction not only suppressed the cell growth and increased apoptosis in AGS and MKN28 cells, but also reduced the migration and invasion ability of these cells. Furthermore, an in vivo xenograft assay revealed that the expression level of CCAR1 was critical for tumorigenesis. Our data demonstrates that CCAR1 contributes to carcinogenesis in gastric cancer and is required for the survival of gastric cancer cells. Moreover, CCAR1 may serve as a diagnostic marker and a potential therapeutic target. PMID:28230774

  16. MiR130b-Regulation of PPARγ Coactivator- 1α Suppresses Fat Metabolism in Goat Mammary Epithelial Cells

    PubMed Central

    Chen, Zhi; Luo, Jun; Ma, LiuAn; Wang, Hui; Cao, WenTing; Xu, HuiFei; Zhu, JiangJiang; Sun, YuTing; Li, Jun; Yao, DaWei; Kang, Kang; Gou, Deming

    2015-01-01

    Fat metabolism is a complicated process regulated by a series of factors. microRNAs (miRNAs) are a class of negative regulator of proteins and play crucial roles in many biological processes; including fat metabolism. Although there have been some researches indicating that miRNAs could influence the milk fat metabolism through targeting some factors, little is known about the effect of miRNAs on goat milk fat metabolism. Here we utilized an improved miRNA detection assay, S-Poly-(T), to profile the expression of miRNAs in the goat mammary gland in different periods, and found that miR-130b was abundantly and differentially expressed in goat mammary gland. Additionally, overexpressing miR-130b impaired adipogenesis while inhibiting miR-130b enhanced adipogenesis in goat mammary epithelial cells. Utilizing 3’-UTR assay and Western Blot analusis, the protein peroxisome proliferator-activated receptor coactivator-1α (PGC1α), a major regulator of fat metabolism, was demonstrated to be a potential target of miR-130b. Interestingly, miR-130b potently repressed PGC1α expression by targeting both the PGC1α mRNA coding and 3’ untranslated regions. These findings have some insight of miR-130b in mediating adipocyte differentiation by repressing PGC1α expression and this contributes to further understanding about the functional significance of miRNAs in milk fat synthesis. PMID:26579707

  17. Computational Characterization and Prediction of Estrogen Receptor Coactivator Binding Site Inhibitors

    DTIC Science & Technology

    2005-09-01

    Gutendorf, andJ. Westendorf. 2000. Endocrine disruptors in fried meat: PhIP is an estrogen. Proceedings of the American Association for Cancer...binding site of the ERa LBD [3-5]. Because these studies have focused on the estradiol binding site, new potential ER disruptors that bind in the co...activator site have been missed. Our proposal focuses on developing a new computational approach to predict therapeutically useful ERa disruptors by

  18. A novel meta-analytic approach: Mining frequent co-activation patterns in neuroimaging databases

    PubMed Central

    Caspers, Julian; Zilles, Karl; Beierle, Christoph; Rottschy, Claudia; Eickhoff, Simon B.

    2016-01-01

    In recent years, coordinate-based meta-analyses have become a powerful and widely used tool to study coactivity across neuroimaging experiments, a development that was supported by the emergence of large-scale neuroimaging databases like BrainMap. However, the evaluation of co-activation patterns is constrained by the fact that previous coordinate-based meta-analysis techniques like Activation Likelihood Estimation (ALE) and Multilevel Kernel Density Analysis (MKDA) reveal all brain regions that show convergent activity within a dataset without taking into account actual within-experiment co-occurrence patterns. To overcome this issue we here propose a novel meta-analytic approach named PaMiNI that utilizes a combination of two well-established data-mining techniques, Gaussian mixture modeling and the Apriori algorithm. By this, PaMiNI enables a data-driven detection of frequent co-activation patterns within neuroimaging datasets. The feasibility of the method is demonstrated by means of several analyses on simulated data as well as a real application. The analyses of the simulated data show that PaMiNI identifies the brain regions underlying the simulated activation foci and perfectly separates the co-activation patterns of the experiments in the simulations. Furthermore, PaMiNI still yields good results when activation foci of distinct brain regions become closer together or if they are non-Gaussian distributed. For the further evaluation, a real dataset on working memory experiments is used, which was previously examined in an ALE meta-analysis and hence allows a cross-validation of both methods. In this latter analysis, PaMiNI revealed a fronto-parietal “core” network of working memory and furthermore indicates a left-lateralization in this network. Finally, to encourage a widespread usage of this new method, the PaMiNI approach was implemented into a publicly available software system. PMID:24365675

  19. Transient neuronal coactivations embedded in globally propagating waves underlie resting-state functional connectivity.

    PubMed

    Matsui, Teppei; Murakami, Tomonari; Ohki, Kenichi

    2016-06-07

    Resting-state functional connectivity (FC), which measures the correlation of spontaneous hemodynamic signals (HemoS) between brain areas, is widely used to study brain networks noninvasively. It is commonly assumed that spatial patterns of HemoS-based FC (Hemo-FC) reflect large-scale dynamics of underlying neuronal activity. To date, studies of spontaneous neuronal activity cataloged heterogeneous types of events ranging from waves of activity spanning the entire neocortex to flash-like activations of a set of anatomically connected cortical areas. However, it remains unclear how these various types of large-scale dynamics are interrelated. More importantly, whether each type of large-scale dynamics contributes to Hemo-FC has not been explored. Here, we addressed these questions by simultaneously monitoring neuronal calcium signals (CaS) and HemoS in the entire neocortex of mice at high spatiotemporal resolution. We found a significant relationship between two seemingly different types of large-scale spontaneous neuronal activity-namely, global waves propagating across the neocortex and transient coactivations among cortical areas sharing high FC. Different sets of cortical areas, sharing high FC within each set, were coactivated at different timings of the propagating global waves, suggesting that spatial information of cortical network characterized by FC was embedded in the phase of the global waves. Furthermore, we confirmed that such transient coactivations in CaS were indeed converted into spatially similar coactivations in HemoS and were necessary to sustain the spatial structure of Hemo-FC. These results explain how global waves of spontaneous neuronal activity propagating across large-scale cortical network contribute to Hemo-FC in the resting state.

  20. Nuclear Control of Respiratory Chain Expression by Nuclear Respiratory Factors and PGC-1-Related Coactivator

    PubMed Central

    Scarpulla, Richard C.

    2010-01-01

    Expression of the respiratory apparatus depends on both nuclear and mitochondrial genes. Although these genes are sequestered in distinct cellular organelles, their transcription relies on nucleus-encoded factors. Certain of these factors are directed to the mitochondria, where they sponsor the bi-directional transcription of mitochondrial DNA. Others act on nuclear genes that encode the majority of the respiratory subunits and many other gene products required for the assembly and function of the respiratory chain. The nuclear respiratory factors, NRF-1 and NRF-2, contribute to the expression of respiratory subunits and mitochondrial transcription factors and thus have been implicated in nucleo-mitochondrial interactions. In addition, coactivators of the PGC-1 family serve as mediators between the environment and the transcriptional machinery governing mitochondrial biogenesis. One family member, peroxisome proliferator-activated receptor γ coactivator PGC-1-related coactivator (PRC), is an immediate early gene product that is rapidly induced by mitogenic signals in the absence of de novo protein synthesis. Like other PGC-1 family members, PRC binds NRF-1 and activates NRF-1 target genes. In addition, PRC complexes with NRF-2 and HCF-1 (host cell factor-1) in the activation of NRF-2-dependent promoters. HCF-1 functions in cell-cycle progression and has been identified as an NRF-2 coactivator. The association of these factors with PRC is suggestive of a role for the complex in cell growth. Finally, shRNA-mediated knock down of PRC expression results in a complex phenotype that includes the inhibition of respiratory growth on galactose and the loss of respiratory complexes. Thus, PRC may help integrate the expression of the respiratory apparatus with the cell proliferative program. PMID:19076454

  1. Transient neuronal coactivations embedded in globally propagating waves underlie resting-state functional connectivity

    PubMed Central

    Matsui, Teppei; Murakami, Tomonari; Ohki, Kenichi

    2016-01-01

    Resting-state functional connectivity (FC), which measures the correlation of spontaneous hemodynamic signals (HemoS) between brain areas, is widely used to study brain networks noninvasively. It is commonly assumed that spatial patterns of HemoS-based FC (Hemo-FC) reflect large-scale dynamics of underlying neuronal activity. To date, studies of spontaneous neuronal activity cataloged heterogeneous types of events ranging from waves of activity spanning the entire neocortex to flash-like activations of a set of anatomically connected cortical areas. However, it remains unclear how these various types of large-scale dynamics are interrelated. More importantly, whether each type of large-scale dynamics contributes to Hemo-FC has not been explored. Here, we addressed these questions by simultaneously monitoring neuronal calcium signals (CaS) and HemoS in the entire neocortex of mice at high spatiotemporal resolution. We found a significant relationship between two seemingly different types of large-scale spontaneous neuronal activity—namely, global waves propagating across the neocortex and transient coactivations among cortical areas sharing high FC. Different sets of cortical areas, sharing high FC within each set, were coactivated at different timings of the propagating global waves, suggesting that spatial information of cortical network characterized by FC was embedded in the phase of the global waves. Furthermore, we confirmed that such transient coactivations in CaS were indeed converted into spatially similar coactivations in HemoS and were necessary to sustain the spatial structure of Hemo-FC. These results explain how global waves of spontaneous neuronal activity propagating across large-scale cortical network contribute to Hemo-FC in the resting state. PMID:27185944

  2. 'Co-active coaching' could help HIV patients. New type of counseling involves goal-setting.

    PubMed

    Garfinkel, M; Blumenthal, E

    2001-08-01

    A counseling technique that takes an action-oriented approach to helping people make major life changes, much used by business executives and other professionals in recent years, now appears to offer some value to HIV patients. Co-active coaching could be a solution to mild depression and inertia for some HIV-infected patients who have difficulty making decisions about how to spend a life-time living with the disease.

  3. Dcp1 links coactivators of mRNA decapping to Dcp2 by proline recognition.

    PubMed

    Borja, Mark S; Piotukh, Kirill; Freund, Christian; Gross, John D

    2011-02-01

    Cap hydrolysis is a critical step in several eukaryotic mRNA decay pathways and is carried out by the evolutionarily conserved decapping complex containing Dcp2 at the catalytic core. In yeast, Dcp1 is an essential activator of decapping and coactivators such as Edc1 and Edc2 are thought to enhance activity, though their mechanism remains elusive. Using kinetic analysis we show that a crucial function of Dcp1 is to couple the binding of coactivators of decapping to activation of Dcp2. Edc1 and Edc2 bind Dcp1 via its EVH1 proline recognition site and stimulate decapping by 1000-fold, affecting both the K(M) for mRNA and rate of the catalytic step. The C-terminus of Edc1 is necessary and sufficient to enhance the catalytic step, while the remainder of the protein likely increases mRNA binding to the decapping complex. Lesions in the Dcp1 EVH1 domain or the Edc1 proline-rich sequence are sufficient to block stimulation. These results identify a new role of Dcp1, which is to link the binding of coactivators to substrate recognition and activation of Dcp2.

  4. Physical and functional interactions of human papillomavirus E2 protein with nuclear receptor coactivators

    SciTech Connect

    Wu, M.-H.; Huang, C.-J.; Liu, S.-T.; Liu, P.-Y.; Ho, C.-L. . E-mail: shihming@ndmctsgh.edu.tw

    2007-05-11

    In addition to the human papillomavirus (HPV)-induced immortalization of epithelial cells, which usually requires integration of the viral DNA into the host cell genome, steroid hormone-activated nuclear receptors (NRs) are thought to bind to specific DNA sequences within transcriptional regulatory regions on the long control region to either increase or suppress transcription of dependent genes. In this study, our data suggest that the NR coactivator function of HPV E2 proteins might be mediated through physical and functional interactions with not only NRs but also the NR coactivators GRIP1 (glucocorticoid receptor-interacting protein 1) and Zac1 (zinc-finger protein which regulates apoptosis and cell cycle arrest 1), reciprocally regulating their transactivation activities. GRIP1 and Zac1 both were able to act synergistically with HPV E2 proteins on the E2-, androgen receptor-, and estrogen receptor-dependent transcriptional activation systems. GRIP1 and Zac1 might selectively function with HPV E2 proteins on thyroid receptor- and p53-dependent transcriptional activation, respectively. Hence, the transcriptional function of E2 might be mediated through NRs and NR coactivators to regulate E2-, NR-, and p53-dependent transcriptional activations.

  5. Human ZCCHC12 activates AP-1 and CREB signaling as a transcriptional co-activator.

    PubMed

    Li, Hong; Liu, Qian; Hu, Xiang; Feng, Du; Xiang, Shuanglin; He, Zhicheng; Hu, Xingwang; Zhou, Jianlin; Ding, Xiaofeng; Zhou, Chang; Zhang, Jian

    2009-07-01

    Mouse zinc finger CCHC domain containing 12 gene (ZCCHC12) has been identified as a transcriptional co-activator of bone morphogenetic protein (BMP) signaling, and human ZCCHC12 was reported to be related to non-syndromic X-linked mental retardation (NS-XLMR). However, the details of how human ZCCHC12 involve in the NS-XLMR still remain unclear. In this study, we identified a novel nuclear localization signal (NLS) in the middle of human ZCCHC12 protein which is responsible for the nuclear localization. Multiple-tissue northern blot analysis indicated that ZCCHC12 is highly expressed in human brain. Furthermore, in situ hybridization showed that ZCCHC12 is specifically expressed in neuroepithelium of forebrain, midbrain, and diencephalon regions of mouse E10.5 embryos. Luciferase reporter assays demonstrated that ZCCHC12 enhanced the transcriptional activities of activator protein 1 (AP-1) and cAMP response element binding protein (CREB) as a coactivator. In conclusion, we identified a new NLS in ZCCHC12 and figured out that ZCCHC12 functions as a transcriptional co-activator of AP-1 and CREB.

  6. Control of Foxo1 Gene Expression by Co-activator P300*

    PubMed Central

    Wondisford, Anne R.; Xiong, Lishou; Chang, Evan; Meng, Shumei; Meyers, David J.; Li, Mingsong; Cole, Philip A.; He, Ling

    2014-01-01

    FOXO1 is an important downstream mediator of the insulin signaling pathway. In the fed state, elevated insulin phosphorylates FOXO1 via AKT, leading to its nuclear exclusion and degradation. A reduction in nuclear FOXO1 levels then leads to suppression of hepatic glucose production. However, the mechanism leading to expression of Foxo1 gene in the fasted state is less clear. We found that Foxo1 mRNA and FOXO1 protein levels of Foxo1 were increased significantly in the liver of mice after 16 h of fasting. Furthermore, dibutyrl cAMP stimulated the expression of Foxo1 at both mRNA and protein level in hepatocytes. Because cAMP-PKA regulates hepatic glucose production through cAMP-response element-binding protein co-activators, we depleted these co-activators using adenoviral shRNAs. Interestingly, only depletion of co-activator P300 resulted in the decrease of Foxo1 mRNA and FOXO1 protein levels. In addition, inhibition of histone acetyltransferase activity of P300 significantly decreased hepatic Foxo1 mRNA and FOXO1 protein levels in fasted mice, as well as fasting blood glucose levels. By characterization of Foxo1 gene promoter, P300 regulates the Foxo1 gene expression through the binding to tandem cAMP-response element sites in the proximal promoter region of Foxo1 gene. PMID:24379407

  7. Antagonist muscle co-activation of limbs in human infant crawling: A pilot study.

    PubMed

    Xiong, Qi L; Wu, Xiao Y; Xiao, Nong; Zeng, Si Y; Wan, Xiao P; Zheng, Xiao L; Hou, Wen S

    2015-01-01

    Muscle Co-activation (MCo) is the simultaneous muscular activation of agonist and antagonist muscle groups, which provides adequate joint stability, movement accuracy during movement. Infant crawling is an important stage of motor function development that manifests non-synchronization growth and development of upper and lower limbs due to the well-known gross motor development principle of head to toe. However, the effect of MCo level for agonist and antagonist muscle groups on motor function development of limbs has not been previously reported. In this paper, sEMG signals were collected from triceps brachii (TB) and biceps brachii (BB), quadriceps femoris (QF) and hamstrings (HS) of limbs when fourteen infants were crawling at their self-selected speed. Antagonist muscle co-activation was evaluated by measuring two common indexes (co-activation index and Pearson's correlation coefficient).A significant difference was observed between upper limbs and lower limbs, but the relationship between MCo and speed of crawling was poor. This study is an opening for further investigation including a longitudinal study and compare against infant with CNS disorders.

  8. PRIC320, a transcription coactivator, isolated from peroxisome proliferator-binding protein complex

    SciTech Connect

    Surapureddi, Sailesh; Viswakarma, Navin; Yu Songtao; Guo Dongsheng; Rao, M. Sambasiva; Reddy, Janardan K. . E-mail: jkreddy@northwestern.edu

    2006-05-05

    Ciprofibrate, a potent peroxisome proliferator, induces pleiotropic responses in liver by activating peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}), a nuclear receptor. Transcriptional regulation by liganded nuclear receptors involves the participation of coregulators that form multiprotein complexes possibly to achieve cell and gene specific transcription. SDS-PAGE and matrix-assisted laser desorption/ionization reflection time-of-flight mass spectrometric analyses of ciprofibrate-binding proteins from liver nuclear extracts obtained using ciprofibrate-Sepharose affinity matrix resulted in the identification of a new high molecular weight nuclear receptor coactivator, which we designated PRIC320. The full-length human cDNA encoding this protein has an open-reading frame that codes for a 320 kDa protein containing 2882 amino acids. PRIC320 contains five LXXLL signature motifs that mediate interaction with nuclear receptors. PRIC320 binds avidly to nuclear receptors PPAR{alpha}, CAR, ER{alpha}, and RXR, but only minimally with PPAR{gamma}. PRIC320 also interacts with transcription cofactors CBP, PRIP, and PBP. Immunoprecipitation-immunoblotting as well as cellular localization studies confirmed the interaction between PPAR{alpha} and PRIC320. PRIC320 acts as a transcription coactivator by stimulating PPAR{alpha}-mediated transcription. We conclude that ciprofibrate, a PPAR{alpha} ligand, binds a multiprotein complex and PRIC320 cloned from this complex functions as a nuclear receptor coactivator.

  9. Regulation of homocysteine homeostasis through the transcriptional coactivator PGC-1α

    PubMed Central

    Li, Siming; Arning, Erland; Liu, Chang; Vitvitsky, Victor; Hernandez, Carlos; Banerjee, Ruma; Bottiglieri, Teodoro; Lin, Jiandie D.

    2009-01-01

    Plasma homocysteine (Hcy) is an independent risk factor for cardiovascular disease. Hcy is a nonprotein amino acid derivative that is generated from the methionine cycle, which provides the methyl group for essentially all biological methylation reactions. Although plasma Hcy levels are elevated in patients with cardiovascular disease, the mechanisms that regulate Hcy homeostasis remain poorly defined. In this study, we found that the expression of key enzymes involved in Hcy metabolism is induced in the liver in response to fasting. This induction coincides with increased expression of peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, a transcriptional coactivator that regulates hepatic gluconeogenesis and mitochondrial function. PGC-1α stimulates the expression of genes involved in Hcy metabolism in cultured primary hepatocytes as well as in the liver. Adenoviral-mediated expression of PGC-1α in vivo leads to elevated plasma Hcy levels. In contrast, mice deficient in PGC-1α have lower plasma Hcy concentrations. These results define a novel role for the PGC-1α coactivator pathway in the regulation of Hcy homeostasis and suggest a potential pathogenic mechanism that contributes to hyperhomocysteinemia. PMID:19158324

  10. Identification of the functional domains of ANT-1, a novel coactivator of the androgen receptor

    SciTech Connect

    Fan Shuli; Goto, Kiminobu; Chen Guangchun; Morinaga, Hidetaka; Nomura, Masatoshi; Okabe, Taijiro; Nawata, Hajime; Yanase, Toshihiko . E-mail: yanase@intmed3.med.kyushu-u.ac.jp

    2006-03-03

    Previously, we identified a transcriptional coactivator for the activation function-1 (AF-1) domain of the human androgen receptor (AR) and designated it androgen receptor N-terminal domain transactivating protein-1 (ANT-1). This coactivator, which contains multiple tetratricopeptide repeat (TPR) motifs from amino acid (aa) 294, is identical to a component of U5 small nuclear ribonucleoprotein particles and binds specifically to the AR or glucocorticoid receptor. Here, we identified four distinct functional domains. The AR-AF-1-binding domain, which bound to either aa 180-360 or 360-532 in AR-AF-1, clearly overlapped with TAU-1 and TAU-5. This domain and the subnuclear speckle formation domain in ANT-1 were assigned within the TPR motifs, while the transactivating and nuclear localization signal domains resided within the N-terminal sequence. The existence of these functional domains may further support the idea that ANT-1 can function as an AR-AF-1-specific coactivator while mediating a transcription-splicing coupling.

  11. Agonist ligands mediate the transcriptional response of nuclear receptor heterodimers through distinct stoichiometric assemblies with coactivators.

    PubMed

    Pavlin, Mark Remec; Brunzelle, Joseph S; Fernandez, Elias J

    2014-09-05

    The constitutive androstane (CAR) and retinoid X receptors (RXR) are ligand-mediated transcription factors of the nuclear receptor protein superfamily. Functional CAR:RXR heterodimers recruit coactivator proteins, such as the steroid receptor coactivator-1 (SRC1). Here, we show that agonist ligands can potentiate transactivation through both coactivator binding sites on CAR:RXR, which distinctly bind two SRC1 molecules. We also observe that SRC1 transitions from a structurally plastic to a compact form upon binding CAR:RXR. Using small angle x-ray scattering (SAXS) we show that the CAR(tcp):RXR(9c)·SRC1 complex can encompass two SRC1 molecules compared with the CAR(tcp):RXR·SRC1, which binds only a single SRC1. Moreover, sedimentation coefficients and molecular weights determined by analytical ultracentrifugation confirm the SAXS model. Cell-based transcription assays show that disrupting the SRC1 binding site on RXR alters the transactivation by CAR:RXR. These data suggest a broader role for RXR within heterodimers, whereas offering multiple strategies for the assembly of the transcription complex. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. The p160 nuclear receptor co-activator RAC3 exerts an anti-apoptotic role through a cytoplasmatic action.

    PubMed

    Colo, G P; Rubio, M F; Nojek, I M; Werbajh, S E; Echeverría, P C; Alvarado, C V; Nahmod, V E; Galigniana, M D; Costas, M A

    2008-04-10

    The p160 nuclear receptor co-activators represent a family of molecules, which are recruited by steroid nuclear receptors as well as other transcription factors that are overexpressed in several tumors. We investigated the role of one member of this family on the sensitivity of cells to apoptosis. We observed that overexpression of the RAC3 (receptor-associated co-activator-3) p160 co-activator inhibits hydrogen peroxide-induced cell death in human embryonic kidney 293 (HEK293) cells. The mechanism involves the activation of anti-apoptotic pathways mediated through enhanced nuclear factor kappa B (NF-kappaB) activity, inhibition of caspase-9 activation, diminished apoptotic-inducing factor (AIF) nuclear localization and a change in the activation pattern of several kinases, including an increase in both AKT and p38 kinase activities, and inhibition of ERK2. Moreover, RAC3 has been found associated with a protein complex containing AIF, Hsp90 and dynein, suggesting a role for the co-activator in the cytoplasmatic nuclear transport of these proteins associated with cytoskeleton. These results demonstrate that there are several molecular pathways that could be affected by their overexpression, including those not restricted to steroid regulation or the nuclear action of co-activators, which results in diminished sensitivity to apoptosis. Furthermore, this could represent one mechanism by which co-activators contribute to tumor development.

  13. Dax-1 and Steroid Receptor RNA Activator (SRA) Function as Transcriptional Coactivators for Steroidogenic Factor 1 in Steroidogenesis▿

    PubMed Central

    Xu, Bin; Yang, Wei-Hsiung; Gerin, Isabelle; Hu, Chang-Deng; Hammer, Gary D.; Koenig, Ronald J.

    2009-01-01

    The nuclear receptor steroidogenic factor 1 (SF-1) is essential for adrenal development and steroidogenesis. The atypical orphan nuclear receptor Dax-1 binds to SF-1 and represses SF-1 target genes. Paradoxically, however, loss-of-function mutations of Dax-1 also cause adrenal hypoplasia, suggesting that Dax-1 may function as an SF-1 coactivator under some circumstances. Indeed, we found that Dax-1 can function as a dosage-dependent SF-1 coactivator. Both SF-1 and Dax-1 bind to steroid receptor RNA activator (SRA), a coactivator that functions as an RNA. The coactivator TIF2 also associates with Dax-1 and synergistically coactivates SF-1 target gene transcription. A naturally occurring Dax-1 mutation inhibits this transactivation, and the mutant Dax-1-TIF2 complex mislocalizes in living cells. Coactivation by Dax-1 is abolished by SRA knockdown. The expression of the steroidogenic gene products steroidogenic acute regulatory protein (StAR) and melanocortin 2 receptor is reduced in adrenal Y1 cells following the knockdown of endogenous SRA. Similarly, the knockdown of endogenous Dax-1 downregulates the expression of the steroidogenic gene products CYP11A1 and StAR in both H295R adrenal and MA-10 Leydig cells. These findings reveal novel functions of SRA and Dax-1 in steroidogenesis and adrenal biology. PMID:19188450

  14. A coactivator trap identifies NONO (p54nrb) as a component of the cAMP-signaling pathway.

    PubMed

    Amelio, Antonio L; Miraglia, Loren J; Conkright, Juliana J; Mercer, Becky A; Batalov, Serge; Cavett, Valerie; Orth, Anthony P; Busby, Jennifer; Hogenesch, John B; Conkright, Michael D

    2007-12-18

    Signal transduction pathways often use a transcriptional component to mediate adaptive cellular responses. Coactivator proteins function prominently in these pathways as the conduit to the basic transcriptional machinery. Here we present a high-throughput cell-based screening strategy, termed the "coactivator trap," to study the functional interactions of coactivators with transcription factors. We applied this strategy to the cAMP signaling pathway, which utilizes two families of coactivators, the cAMP response element binding protein (CREB) binding protein (CBP)/p300 family and the recently identified transducers of regulated CREB activity family (TORCs1-3). In addition to identifying numerous known interactions of these coactivators, this analysis identified NONO (p54(nrb)) as a TORC-interacting protein. RNA interference experiments demonstrate that NONO is necessary for cAMP-dependent activation of CREB target genes in vivo. Furthermore, TORC2 and NONO complex on cAMP-responsive promoters, and NONO acts as a bridge between the CREB/TORC complex and RNA polymerase II. These data demonstrate the utility of the coactivator trap by identification of a component of cAMP-mediated transcription.

  15. Play Therapy: A Review

    ERIC Educational Resources Information Center

    Porter, Maggie L.; Hernandez-Reif, Maria; Jessee, Peggy

    2009-01-01

    This article discusses the current issues in play therapy and its implications for play therapists. A brief history of play therapy is provided along with the current play therapy approaches and techniques. This article also touches on current issues or problems that play therapists may face, such as interpreting children's play, implementing…

  16. Play Therapy: A Review

    ERIC Educational Resources Information Center

    Porter, Maggie L.; Hernandez-Reif, Maria; Jessee, Peggy

    2009-01-01

    This article discusses the current issues in play therapy and its implications for play therapists. A brief history of play therapy is provided along with the current play therapy approaches and techniques. This article also touches on current issues or problems that play therapists may face, such as interpreting children's play, implementing…

  17. Abnormal coactivation of knee and ankle extensors is related to changes in heteronymous spinal pathways after stroke

    PubMed Central

    2011-01-01

    Background Abnormal coactivation of leg extensors is often observed on the paretic side of stroke patients while they attempt to move. The mechanisms underlying this coactivation are not well understood. This study (1) compares the coactivation of leg extensors during static contractions in stroke and healthy individuals, and (2) assesses whether this coactivation is related to changes in intersegmental pathways between quadriceps and soleus (Sol) muscles after stroke. Methods Thirteen stroke patients and ten healthy individuals participated in the study. Levels of coactivation of knee extensors and ankle extensors were measured in sitting position, during two tasks: maximal isometric voluntary contractions in knee extension and in plantarflexion. The early facilitation and later inhibition of soleus voluntary EMG evoked by femoral nerve stimulation were assessed in the paretic leg of stroke participants and in one leg of healthy participants. Results Coactivation levels of ankle extensors (mean ± SEM: 56 ± 7% of Sol EMG max) and of knee extensors (52 ± 10% of vastus lateralis (VL) EMG max) during the knee extension and the ankle extension tasks respectively were significantly higher in the paretic leg of stroke participants than in healthy participants (26 ± 5% of Sol EMG max and 10 ± 3% of VL EMG max, respectively). Early heteronymous facilitation of Sol voluntary EMG in stroke participants (340 ± 62% of Sol unconditioned EMG) was significantly higher than in healthy participants (98 ± 34%). The later inhibition observed in all control participants was decreased in the paretic leg. Levels of coactivation of ankle extensors during the knee extension task were significantly correlated with both the increased facilitation (Pearson r = 0.59) and the reduced inhibition (r = 0.56) in the paretic leg. Measures of motor impairment were more consistently correlated with the levels of coactivation of biarticular muscles than those of monoarticular muscles

  18. Children's Play and Television.

    ERIC Educational Resources Information Center

    Powell, Mark

    2001-01-01

    Discusses adverse effects of FCC deregulation of children's television programming on children's play behavior. Discusses the difference between play and imitation, the role of high quality dramatic play in healthy child development, the popularity of war play, and use of toys to increase dramatic play. Considers ways to help children gain control…

  19. Children's Play and Television.

    ERIC Educational Resources Information Center

    Powell, Mark

    2001-01-01

    Discusses adverse effects of FCC deregulation of children's television programming on children's play behavior. Discusses the difference between play and imitation, the role of high quality dramatic play in healthy child development, the popularity of war play, and use of toys to increase dramatic play. Considers ways to help children gain control…

  20. The Denial of Play.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Well meaning parents and teachers often use children's play for the purposes of literacy and socialization. Yet, these attempts may deny play to children by subordinating play to some other concept. Evidence shows that even when parents play with their very young children they generally play games like shopping, cooking, and eating; whereas when…

  1. The Denial of Play.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Well meaning parents and teachers often use children's play for the purposes of literacy and socialization. Yet, these attempts may deny play to children by subordinating play to some other concept. Evidence shows that even when parents play with their very young children they generally play games like shopping, cooking, and eating; whereas when…

  2. War, Conflict and Play. Debating Play

    ERIC Educational Resources Information Center

    Hyder, Tina

    2004-01-01

    Young refugees from many parts of the world are increasingly present in UK early years settings. This book explores the crucial importance of play for young refugee children's development. It considers the implications of war and conflict on young children and notes how opportunities for play are denied. It provides a framework for early years…

  3. A temporal examination of co-activated emotion valence networks in schizophrenia and schizotypy.

    PubMed

    Cohen, Alex S; Callaway, Dallas A; Mitchell, Kyle R; Larsen, Jeff T; Strauss, Gregory P

    2016-02-01

    Emotional abnormalities are prominent across the schizophrenia spectrum. To better define these abnormalities, we examined state emotional functions across opposing ends of the spectrum, notably in chronic outpatients with schizophrenia (Study 1) and college students with psychometrically defined schizotypy (Study 2). In line with existing studies, we predicted that individuals with schizophrenia would show unusually co-activated positive and negative emotions while college students with schizotypy would show abnormally low positive and abnormally high negative emotions. Drawing from the affective science literature, we employed continuous emotion ratings in response to a dynamic and evocatively "bittersweet" stimulus. Participants included 27 individuals with schizophrenia, 39 individuals with psychometrically defined schizotypy and 26 community and 35 college control participants. Participants continuously rated their state happiness and sadness throughout a six-minute clip from a tragicomic film (i.e., Life is Beautiful). In contrast to expectations as well as the extant literature, there were no state emotional abnormalities noted from either schizophrenia-spectrum group. Of particular note, neither individuals with schizophrenia nor individuals with schizotypy were abnormal in their experience of state negative, positive or coactivated emotions. Conversely, abnormalities in trait emotion were observed in both groups relative to their respective control groups. These results help confirm that the schizophrenia-spectrum is not characterized by deficits in state emotional experience and suggest that sadness is not abnormally co-activated with pleasant emotions. These results are critical for clarifying the "chronometry" of emotional dysfunctions across the schizophrenia-spectrum. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Insights into Degron Recognition by APC/C Coactivators from the Structure of an Acm1-Cdh1 Complex

    PubMed Central

    He, Jun; Chao, William C.H.; Zhang, Ziguo; Yang, Jing; Cronin, Nora; Barford, David

    2013-01-01

    Summary The anaphase-promoting complex/cyclosome (APC/C) regulates sister chromatid segregation and the exit from mitosis. Selection of most APC/C substrates is controlled by coactivator subunits (either Cdc20 or Cdh1) that interact with substrate destruction motifs—predominantly the destruction (D) box and KEN box degrons. How coactivators recognize D box degrons and how this is inhibited by APC/C regulatory proteins is not defined at the atomic level. Here, from the crystal structure of S. cerevisiae Cdh1 in complex with its specific inhibitor Acm1, which incorporates D and KEN box pseudosubstrate motifs, we describe the molecular basis for D box recognition. Additional interactions between Acm1 and Cdh1 identify a third protein-binding site on Cdh1 that is likely to confer coactivator-specific protein functions including substrate association. We provide a structural rationalization for D box and KEN box recognition by coactivators and demonstrate that many noncanonical APC/C degrons bind APC/C coactivators at the D box coreceptor. PMID:23707760

  5. Identification of SRC3/AIB1 as a Preferred Coactivator for Hormone-activated Androgen Receptor*♦

    PubMed Central

    Zhou, X. Edward; Suino-Powell, Kelly M.; Li, Jun; He, Yuanzheng; MacKeigan, Jeffrey P.; Melcher, Karsten; Yong, Eu-Leong; Xu, H. Eric

    2010-01-01

    Transcription activation by androgen receptor (AR), which depends on recruitment of coactivators, is required for the initiation and progression of prostate cancer, yet the mechanisms of how hormone-activated AR interacts with coactivators remain unclear. This is because AR, unlike any other nuclear receptor, prefers its own N-terminal FXXLF motif to the canonical LXXLL motifs of coactivators. Through biochemical and crystallographic studies, we identify that steroid receptor coactivator-3 (SRC3) (also named as amplified in breast cancer-1 or AIB1) interacts strongly with AR via synergistic binding of its first and third LXXLL motifs. Mutagenesis and functional studies confirm that SRC3 is a preferred coactivator for hormone-activated AR. Importantly, AR mutations found in prostate cancer patients correlate with their binding potency to SRC3, corroborating with the emerging role of SRC3 as a prostate cancer oncogene. These results provide a molecular mechanism for the selective utilization of SRC3 by hormone-activated AR, and they link the functional relationship between AR and SRC3 to the development and growth of prostate cancer. PMID:20086010

  6. Agonist muscle activity and antagonist muscle co-activity levels during standardized isotonic and isokinetic knee extensions.

    PubMed

    Remaud, Anthony; Cornu, Christophe; Guével, Arnaud

    2009-06-01

    This study aimed to analyze the effects of the contraction mode (isotonic vs. isokinetic concentric conditions), the joint angle and the investigated muscle on agonist muscle activity and antagonist muscle co-activity during standardized knee extensions. Twelve healthy adult subjects performed three sets of isotonic knee extensions at 40% of their maximal voluntary isometric torque followed by three sets of maximal isokinetic knee extensions on an isokinetic dynamometer. For each set, the mean angular velocity and the total external amount of work performed were standardized during the two contraction modes. Surface electromyographic activity of vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), semitendinosus (ST) and biceps femoris (BF) muscles was recorded. Root mean square values were then calculated for each 10 degrees between 85 degrees and 45 degrees of knee extension (0 degrees =horizontal position). Results show that agonist muscle activity and antagonist muscle co-activity levels are significantly greater in isotonic mode compared to isokinetic mode. Quadriceps activity and hamstrings co-activity are significantly lower at knee extended position in both contraction modes. Considering agonist muscles, VL reveals a specific pattern of activity compared to VM and RF; whereas considering hamstring muscles, BF shows a significantly higher co-activity than ST in both contraction modes. Results of this study confirmed our hypothesis that higher quadriceps activity is required during isotonic movements compared to isokinetic movements leading to a higher hamstrings co-activity.

  7. Distinct roles of the steroid receptor coactivator 1 and of MED1 in retinoid-induced transcription and cellular differentiation.

    PubMed

    Flajollet, Sébastien; Lefebvre, Bruno; Rachez, Christophe; Lefebvre, Philippe

    2006-07-21

    Retinoic acid receptors (RARs) are the molecular relays of retinoid action on transcription, cellular differentiation and apoptosis. Transcriptional activation of retinoid-regulated promoters requires the dismissal of corepressors and the recruitment of coactivators to promoter-bound RAR. RARs recruit in vitro a plethora of coactivators whose actual contribution to retinoid-induced transcription is poorly characterized in vivo. Embryonal carcinoma P19 cells, which are highly sensitive to retinoids, were depleted from archetypical coactivators by RNAi. SRC1-deficient P19 cells showed severely compromised retinoid-induced responses, in agreement with the supposed role of SRC1 as a RAR coactivator. Unexpectedly, Med1/TRAP220/DRIP205-depleted cells exhibited an exacerbated response to retinoids, both in terms transcriptional responses and of cellular differentiation. Med1 depletion affected TFIIH and cdk9 detection at the prototypical retinoid-regulated RARbeta2 promoter, and favored a higher RNA polymerase II detection in transcribed regions of the RARbeta2 gene. Furthermore, the nature of the ligand impacted strongly on the ability of RARs to interact with a given coactivator and to activate transcription in intact cells. Thus RAR accomplishes transcriptional activation as a function of the ligand structure, by recruiting regulatory complexes which control distinct molecular events at retinoid-regulated promoters.

  8. Task vs. rest—different network configurations between the coactivation and the resting-state brain networks

    PubMed Central

    Di, Xin; Gohel, Suril; Kim, Eun H.; Biswal, Bharat B.

    2013-01-01

    There is a growing interest in studies of human brain networks using resting-state functional magnetic resonance imaging (fMRI). However, it is unclear whether and how brain networks measured during the resting-state exhibit comparable properties to brain networks during task performance. In the present study, we investigated meta-analytic coactivation patterns among brain regions based upon published neuroimaging studies, and compared the coactivation network configurations with those in the resting-state network. The strength of resting-state functional connectivity between two regions were strongly correlated with the coactivation strength. However, the coactivation network showed greater global efficiency, smaller mean clustering coefficient, and lower modularity compared with the resting-state network, which suggest a more efficient global information transmission and between system integrations during task performing. Hub shifts were also observed within the thalamus and the left inferior temporal cortex. The thalamus and the left inferior temporal cortex exhibited higher and lower degrees, respectively in the coactivation network compared with the resting-state network. These results shed light regarding the reconfiguration of the brain networks between task and resting-state conditions, and highlight the role of the thalamus in change of network configurations in task vs. rest. PMID:24062654

  9. Targeting of the Nuclear Receptor Coactivator Isoform DELTA3AIB1 in Breast Cancer

    DTIC Science & Technology

    2007-03-01

    lab showed that the downregulation of overall levels of AIB1 plus ∆3AIB1, using a regulatable AIB1 directed ribozyme , resulted in reduced tumor...overall levels of AIB1 plus ∆3AIB1, using a regulatable AIB1 directed ribozyme , resulted in reduced tumor growth in vivo. Overall, these data indicate a...Reiter R, Powers C, Wellstein A, Riegel AT. Ribozyme targeting shows that the nuclear receptor coactivator AIB1 is a rate-limiting factor for estrogen

  10. Targeting of the Nuclear Receptor Coactivator Isoform Delta3Air in Breast Cancer

    DTIC Science & Technology

    2005-03-01

    Annabell Oh on a study in which siRNA directed at nucleotides 564-582 of AIBI to selectively reduce AIBI gene expression in the MCF-7 breast cancer...I mediates Insulin-like Growth Factor 1-Induced Phenotypic Changes in Human Breast Cancer Cells." Annabell Oh, Heinz Joachim List, Ronald Reiter...Receptor Coactivator AIB1 Mediates Insulin-like Growth Factor I-induced Phenotypic Changes in Human Breast Cancer Cells Annabell Oh,1 Heinz-Joachim List,1

  11. EGF Regulation of Nuclear Co-Activator AIB1 Function in Breast Cancer

    DTIC Science & Technology

    2005-04-01

    AD Award Number: DAMDl7-02-1-0394 TITLE: EGF Regulation of Nuclear Co-Activator AIBI Function in Breast Cancer PRINCIPAL INVESTIGATOR: Annabell S. Oh...Activator AIBI Function in DAMD17-02-1-0394 Breast Cancer 6. AUTHOR(S) Annabell S. Oh 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING...Factor-i Signaling in Human Breast Cancer. Doctoral dissertation of Annabell S. Oh, B.S. from the Department 14 of Tumor Biology, Georgetown

  12. Structural basis for cooperativity in recruitment of MAML coactivators to Notch transcription complexes.

    PubMed

    Nam, Yunsun; Sliz, Piotr; Song, Luyan; Aster, Jon C; Blacklow, Stephen C

    2006-03-10

    Notch receptors transduce essential developmental signals between neighboring cells by forming a complex that leads to transcription of target genes upon activation. We report here the crystal structure of a Notch transcriptional activation complex containing the ankyrin domain of human Notch1 (ANK), the transcription factor CSL on cognate DNA, and a polypeptide from the coactivator Mastermind-like-1 (MAML-1). Together, CSL and ANK create a groove to bind the MAML-1 polypeptide as a kinked, 70 A helix. The composite binding surface likely restricts the recruitment of MAML proteins to promoters on which Notch:CSL complexes have been preassembled, ensuring tight transcriptional control of Notch target genes.

  13. Involvement of Steroid Receptor Coactivators/Ubiquitin Pathway Enzymes in Mammary Gland Tumorigenesis

    DTIC Science & Technology

    2005-06-01

    PRINCIPAL INVESTIGATOR: Xiuhua Gao, M.D., Ph.D. CONTRACTING ORGANIZATION: Baylor College of Medicine Houston, TX 77030 REPORT DATE: June 2005 TYPE OF REPORT...Summary 13 May 2002 - 12 May 2005 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Involvement of Steroid Receptor Coactivators/Ubiquitin Pathway 5b...Usell tc localization of MUcle ~s. Eý a, Eý Ca exaressiorn Crofile; E-p groffle; W1~’, API staining for nUcleUs. E6-AP DAMP -HI +E Figure 2: Effect of

  14. Validation of chemical compound library screening for transcriptional co-activator with PDZ-binding motif inhibitors using GFP-fused transcriptional co-activator with PDZ-binding motif.

    PubMed

    Nagashima, Shunta; Maruyama, Junichi; Kawano, Shodai; Iwasa, Hiroaki; Nakagawa, Kentaro; Ishigami-Yuasa, Mari; Kagechika, Hiroyuki; Nishina, Hiroshi; Hata, Yutaka

    2016-06-01

    Transcriptional co-activator with PDZ-binding motif (TAZ) plays versatile roles in cell proliferation and differentiation. It is phosphorylated by large tumor suppressor kinases, the core kinases of the tumor-suppressive Hippo pathway. Phosphorylation induces the cytoplasmic accumulation of TAZ and its degradation. In human cancers, the deregulation of the Hippo pathway and gene amplification enhance TAZ activity. TAZ interacts with TEA domain family members (TEAD), and upregulates genes implicated in epithelial-mesenchymal transition. It also confers stemness to cancer cells. Thus, TAZ activation provides cancer cells with malignant properties and worsens the clinical prognosis. Therefore, TAZ attracts attention as a therapeutic target in cancer therapy. We applied 18 606 small chemical compounds to human osteosarcoma U2OS cells expressing GFP-fused TAZ (GFP-TAZ), monitored the subcellular localization of GFP-TAZ, and selected 33 compounds that shifted GFP-TAZ to the cytoplasm. Unexpectedly, only a limited number of compounds suppressed TAZ-mediated enhancement of TEAD-responsive reporter activity. Moreover, the compounds that weakened TEAD reporter activity did not necessarily decrease the unphosphorylated TAZ. In this study, we focused on three compounds that decreased both TEAD reporter activity and unphosphorylated TAZ, and treated several human cancer cells with these compounds. One compound did not show a remarkable effect, whereas the other two compounds compromised the cell viability in certain cancer cells. In conclusion, the GFP-TAZ-based assay can be used as the first screening for compounds that inhibit TAZ and show anticancer properties. To develop anticancer drugs, we need additional assays to select the compounds.

  15. Nuclear receptor coactivator/coregulator NCoA6(NRC) is a pleiotropic coregulator involved in transcription, cell survival, growth and development

    PubMed Central

    Mahajan, Muktar A.; Samuels, Herbert H.

    2008-01-01

    NCoA6 (also referred to as NRC, ASC-2, TRBP, PRIP and RAP250) was originally isolated as a ligand-dependent nuclear receptor interacting protein. However, NCoA6 is a multifunctional coregulator or coactivator necessary for transcriptional activation of a wide spectrum of target genes. The NCoA6 gene is amplified and overexpressed in breast, colon and lung cancers. NCoA6 is a 250 kDa protein which harbors a potent N-terminal activation domain, AD1; and a second, centrally-located activation domain, AD2, which is necessary for nuclear receptor signaling. The intrinsic activation potential of NCoA6 is regulated by its C-terminal STL regulatory domain. Near AD2 is an LxxLL-1 motif which interacts with a wide spectrum of ligand-bound NRs with high-affinity. A second LxxLL motif (LxxLL-2) located towards the C-terminal region is more restricted in its NR specificity. The potential role of NCoA6 as a co-integrator is suggested by its ability to enhance transcriptional activation of a wide variety of transcription factors and from its in vivo association with a number of known cofactors including CBP/p300. NCoA6 has been shown to associate with at least three distinct coactivator complexes containing Set methyltransferases as core polypeptides. The composition of these complexes suggests that NCoA6 may play a fundamental role in transcriptional activation by modulating chromatin structure through histone methylation. Knockout studies in mice suggest that NCoA6 is an essential coactivator. NCoA6-/- embryos die between 8.5-12.5 dpc from general growth retardation coupled with developmental defects in the heart, liver, brain and placenta. NCoA6-/- MEFs grow at a reduced rate compared to WT MEFs and spontaneously undergo apoptosis, indicating the importance of NCoA6 as a prosurvival and anti-apoptotic gene. Studies with NCoA6+/- and conditional knockout mice suggest that NCoA6 is a pleiotropic coregulator involved in growth, development, wound healing and maintenance of energy

  16. Understanding Playful Pedagogies, Play Narratives and Play Spaces

    ERIC Educational Resources Information Center

    Goouch, Kathy

    2008-01-01

    This paper is a tentative attempt to unwrap and understand one aspect of playful practice and the influences which determine its existence in early years settings. "Storying" events, those occasions when teachers and children together "make up" stories or parts of stories, develop roles or co-construct fantasies, occur moment by moment in some…

  17. Mitochondrial Biogenesis and Peroxisome Proliferator–Activated Receptor-γ Coactivator-1α (PGC-1α) Deacetylation by Physical Activity

    PubMed Central

    Li, Ling; Pan, Ruping; Li, Rong; Niemann, Bernd; Aurich, Anne-Cathleen; Chen, Ying; Rohrbach, Susanne

    2011-01-01

    OBJECTIVE Transcriptional peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α) plays a key role in mitochondrial biogenesis and energy metabolism and is suggested to be involved in the exercise-induced increase in mitochondrial content. PGC-1α activity is regulated by posttranslational modifications, among them acetylation or phosphorylation. Accordingly, the deacetylase SIRT1 and the kinase AMPK increase PGC-1α activity. RESEARCH DESIGN AND METHODS We tested whether chronic treadmill exercise or a single exercise session modifies PGC-1α activation and mitochondrial biogenesis differentially in obese ob/ob mice with dysregulated adiponectin/leptin-mediated AMPK activation compared with C57BL/6J wild-type mice. RESULTS Exercise training (12 weeks) induced adiponectin and lowered plasma insulin and glucose, suggesting improved insulin sensitivity in wild-type mice. It enhanced mitochondrial biogenesis in red gastrocnemius muscle, as indicated by increased mRNA expression of transcriptional regulators and primary mitochondrial transcripts, increased mtDNA content, and citrate synthase activity. Parallel to this, we observed AMPK activation, PGC-1α deacetylation, and SIRT1 induction in trained wild-type mice. Although none of these exercise-induced changes were detected in ob/ob mice, comparable effects on mitochondrial respiration were observed. A single exercise session resulted in comparable changes in wild-type mice. These changes remained detectable 6 h after the exercise session but had disappeared after 24 h. Treatment of C2C12 myoblasts with leptin or adiponectin resulted in increased AMPK phosphorylation and PGC-1α deacetylation. CONCLUSIONS Chronic exercise induces mitochondrial biogenesis in wild-type mice, which may require intact AMPK activation by adipocytokines and involve SIRT1-dependent PGC-1α deacetylation. Trained ob/ob mice appear to have partially adapted to reduced mitochondrial biogenesis by AMPK/SIRT1/PGC-1

  18. SIRT1 is a Direct Coactivator of Thyroid Hormone Receptor β1 with Gene-Specific Actions

    PubMed Central

    Suh, Ji Ho; Sieglaff, Douglas H.; Zhang, Aijun; Xia, Xuefeng; Cvoro, Aleksandra; Winnier, Glenn E.; Webb, Paul

    2013-01-01

    Sirtuin 1 (SIRT1) NAD+-dependent deacetylase regulates energy metabolism by modulating expression of genes involved in gluconeogenesis and other liver fasting responses. While many effects of SIRT1 on gene expression are mediated by deacetylation and activation of peroxisome proliferator activated receptor coactivator α (PGC-1α), SIRT1 also binds directly to DNA bound transcription factors, including nuclear receptors (NRs), to modulate their activity. Since thyroid hormone receptor β1 (TRβ1) regulates several SIRT1 target genes in liver and interacts with PGC-1α, we hypothesized that SIRT1 may influence TRβ1. Here, we confirm that SIRT1 cooperates with PGC-1α to enhance response to triiodothyronine, T3. We also find, however, that SIRT1 stimulates TRβ1 activity in a manner that is independent of PGC-1α but requires SIRT1 deacetylase activity. SIRT1 interacts with TRβ1 in vitro, promotes TRβ1 deacetylation in the presence of T3 and enhances ubiquitin-dependent TRβ1 turnover; a common response of NRs to activating ligands. More surprisingly, SIRT1 knockdown only strongly inhibits T3 response of a subset of TRβ1 target genes, including glucose 6 phosphatase (G-6-Pc), and this is associated with blockade of TRβ1 binding to the G-6-Pc promoter. Drugs that target the SIRT1 pathway, resveratrol and nicotinamide, modulate T3 response at dual TRβ1/SIRT1 target genes. We propose that SIRT1 is a gene-specific TRβ1 co-regulator and TRβ1/SIRT1 interactions could play important roles in regulation of liver metabolic response. Our results open possibilities for modulation of subsets of TR target genes with drugs that influence the SIRT1 pathway. PMID:23922917

  19. von Hippel-Lindau partner Jade-1 is a transcriptional co-activator associated with histone acetyltransferase activity.

    PubMed

    Panchenko, Maria V; Zhou, Mina I; Cohen, Herbert T

    2004-12-31

    Jade-1 was identified as a protein partner of the von Hippel-Lindau tumor suppressor pVHL. The interaction of Jade-1 and pVHL correlates with renal cancer risk. We have investigated the molecular function of Jade-1. Jade-1 has two zinc finger motifs called plant homeodomains (PHD). A line of evidence suggests that the PHD finger functions in chromatin remodeling and protein-protein interactions. We determined the cellular localization of Jade-1 and examined whether Jade-1 might have transcriptional and histone acetyltransferase (HAT) functions. Biochemical cell fractionation studies as well as confocal images of cells immunostained with a specific Jade-1 antibody revealed that endogenous Jade-1 is localized predominantly in the cell nucleus. Tethering of Gal4-Jade-1 fusion protein to Gal4-responsive promoters in co-transfection experiments activated transcription 5-6-fold, indicating that Jade-1 is a possible transcriptional activator. It was remarkable that overexpression of Jade-1 in cultured cells specifically increased levels of endogenous acetylated histone H4, but not histone H3, strongly suggesting that Jade-1 associates with HAT activity specific for histone H4. Deletion of the two PHD fingers completely abolished Jade-1 transcriptional and HAT activities, indicating that these domains are indispensable for Jade-1 nuclear functions. In addition, we demonstrated that TIP60, a known HAT with histone H4/H2A specificity, physically associates with Jade-1 and is able to augment Jade-1 HAT function in live cells, strongly suggesting that TIP60 might mediate Jade-1 HAT activity. Thus, Jade-1 is a novel candidate transcriptional co-activator associated with HAT activity and may play a key role in the pathogenesis of renal cancer and von Hippel-Lindau disease.

  20. Truncated Peroxisome Proliferator-Activated Receptor-γ Coactivator 1α Splice Variant Is Severely Altered in Huntington's Disease

    PubMed Central

    Johri, Ashu; Starkov, Anatoly A.; Chandra, Abhishek; Hennessey, Thomas; Sharma, Abhijeet; Orobello, Sara; Squitieri, Ferdinando; Yang, Lichuan; Beal, M. Flint

    2011-01-01

    Background Reduced peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) gene expression has been observed in striatal cell lines, transgenic mouse models of Huntington's disease (HD), and brain tissue from HD patients. As this protein is a key transcription regulator of the expression of many mitochondrial proteins, these observations strongly support the role of aberrant mitochondrial function in the pathogenesis of HD. The PGC1α protein undergoes posttranslational modifications that affect its transcriptional activity. The N-truncated splice variant of PGC1α (NT-PGC1α) is produced in tissues, but the role of truncated splice variants of PGC1α in HD and in the regulation of mitochondrial gene expression has not been elucidated. Objective To examine the expression and modulation of expression of NT-PGC1α levels in HD. Methods and Results We found that the NT-PGC1α protein, a splice variant of ∼38 kDa, but not full-length PGC1α is severely and consistently altered in human HD brain, human HD myoblasts, mouse HD models, and HD striatal cells. NT-PGC1α levels were significantly upregulated in HD cells and mouse brown fat by physiologically relevant stimuli that are known to upregulate PGC1α gene expression. This resulted in an increase in mitochondrial gene expression and cytochrome c content. Conclusion Our data suggest that NT-PGC1α is an important component of the PGC1α transcriptional network, which plays a significant role in the pathogenesis of HD. Copyright © 2011 S. Karger AG, Basel PMID:21757867

  1. Truncated peroxisome proliferator-activated receptor-γ coactivator 1α splice variant is severely altered in Huntington's disease.

    PubMed

    Johri, Ashu; Starkov, Anatoly A; Chandra, Abhishek; Hennessey, Thomas; Sharma, Abhijeet; Orobello, Sara; Squitieri, Ferdinando; Yang, Lichuan; Beal, M Flint

    2011-01-01

    Reduced peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) gene expression has been observed in striatal cell lines, transgenic mouse models of Huntington's disease (HD), and brain tissue from HD patients. As this protein is a key transcription regulator of the expression of many mitochondrial proteins, these observations strongly support the role of aberrant mitochondrial function in the pathogenesis of HD. The PGC1α protein undergoes posttranslational modifications that affect its transcriptional activity. The N-truncated splice variant of PGC1α (NT-PGC1α) is produced in tissues, but the role of truncated splice variants of PGC1α in HD and in the regulation of mitochondrial gene expression has not been elucidated. To examine the expression and modulation of expression of NT-PGC1α levels in HD. We found that the NT-PGC1α protein, a splice variant of ∼38 kDa, but not full-length PGC1α is severely and consistently altered in human HD brain, human HD myoblasts, mouse HD models, and HD striatal cells. NT-PGC1α levels were significantly upregulated in HD cells and mouse brown fat by physiologically relevant stimuli that are known to upregulate PGC1α gene expression. This resulted in an increase in mitochondrial gene expression and cytochrome c content. Our data suggest that NT-PGC1α is an important component of the PGC1α transcriptional network, which plays a significant role in the pathogenesis of HD. Copyright © 2011 S. Karger AG, Basel.

  2. Oxidized Low-Density Lipoprotein Contributes to Atherogenesis via Co-activation of Macrophages and Mast Cells

    PubMed Central

    Chen, Chong; Khismatullin, Damir B.

    2015-01-01

    Oxidized low-density lipoprotein (OxLDL) is a risk factor for atherosclerosis, due to its role in endothelial dysfunction and foam cell formation. Tissue-resident cells such as macrophages and mast cells release inflammatory mediators upon activation that in turn cause endothelial activation and monocyte adhesion. Two of these mediators are tumor necrosis factor (TNF)-α, produced by macrophages, and histamine, produced by mast cells. Static and microfluidic flow experiments were conducted to determine the number of adherent monocytes on vascular endothelium activated by supernatants of oxLDL-treated macrophages and mast cells or directly by oxLDL. The expression of adhesion molecules on activated endothelial cells and the concentration of TNF-α and histamine in the supernatants were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. A low dose of oxLDL (8 μg/ml), below the threshold for the clinical presentation of coronary artery disease, was sufficient to activate both macrophages and mast cells and synergistically increase monocyte-endothelium adhesion via released TNF-α and histamine. The direct exposure of endothelial cells to a much higher dose of oxLDL (80 μg/ml) had less effect on monocyte adhesion than the indirect activation via oxLDL-treated macrophages and mast cells. The results of this work indicate that the co-activation of macrophages and mast cells by oxLDL is an important mechanism for the endothelial dysfunction and atherogenesis. The observed synergistic effect suggests that both macrophages and mast cells play a significant role in early stages of atherosclerosis. Allergic patients with a lipid-rich diet may be at high risk for cardiovascular events due to high concentration of low-density lipoprotein and histamine in arterial vessel walls. PMID:25811595

  3. Oxidized low-density lipoprotein contributes to atherogenesis via co-activation of macrophages and mast cells.

    PubMed

    Chen, Chong; Khismatullin, Damir B

    2015-01-01

    Oxidized low-density lipoprotein (OxLDL) is a risk factor for atherosclerosis, due to its role in endothelial dysfunction and foam cell formation. Tissue-resident cells such as macrophages and mast cells release inflammatory mediators upon activation that in turn cause endothelial activation and monocyte adhesion. Two of these mediators are tumor necrosis factor (TNF)-α, produced by macrophages, and histamine, produced by mast cells. Static and microfluidic flow experiments were conducted to determine the number of adherent monocytes on vascular endothelium activated by supernatants of oxLDL-treated macrophages and mast cells or directly by oxLDL. The expression of adhesion molecules on activated endothelial cells and the concentration of TNF-α and histamine in the supernatants were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. A low dose of oxLDL (8 μg/ml), below the threshold for the clinical presentation of coronary artery disease, was sufficient to activate both macrophages and mast cells and synergistically increase monocyte-endothelium adhesion via released TNF-α and histamine. The direct exposure of endothelial cells to a much higher dose of oxLDL (80 μg/ml) had less effect on monocyte adhesion than the indirect activation via oxLDL-treated macrophages and mast cells. The results of this work indicate that the co-activation of macrophages and mast cells by oxLDL is an important mechanism for the endothelial dysfunction and atherogenesis. The observed synergistic effect suggests that both macrophages and mast cells play a significant role in early stages of atherosclerosis. Allergic patients with a lipid-rich diet may be at high risk for cardiovascular events due to high concentration of low-density lipoprotein and histamine in arterial vessel walls.

  4. PGC-1-related coactivator (PRC) negatively regulates endothelial adhesion of monocytes via inhibition of NF κB activity

    SciTech Connect

    Chengye, Zhan; Daixing, Zhou Qiang, Zhong; Shusheng, Li

    2013-09-13

    Highlights: •First time to display that LPS downregulate the expression of PRC. •First time to show that PRC inhibits the induction of VCAM-1 and E-selectin. •First time to show that PRC inhibit monocytes attachment to endothelial cells. •First time to display that PRC inhibits transcriptional activity of NF-κB. •PRC protects the respiration rate and suppresses the glycolysis rate against LPS. -- Abstract: PGC-1-related coactivator (PRC) is a growth-regulated transcriptional cofactor known to activate many of the nuclear genes specifying mitochondrial respiratory function. Endothelial dysfunction is a prominent feature found in many inflammatory diseases. Adhesion molecules, such as VCAM-1, mediate the attachment of monocytes to endothelial cells, thereby playing an important role in endothelial inflammation. The effects of PRC in regards to endothelial inflammation remain unknown. In this study, our findings show that PRC can be inhibited by the inflammatory cytokine LPS in cultured human umbilical vein endothelial cells (HUVECs). In the presence of LPS, the expression of endothelial cell adhesion molecular, such as VCAM1 and E-selectin, is found to be increased. These effects can be negated by overexpression of PRC. Importantly, monocyte adhesion to endothelial cells caused by LPS is significantly attenuated by PRC. In addition, overexpression of PRC protects mitochondrial metabolic function and suppresses the rate of glycolysis against LPS. It is also found that overexpression of PRC decreases the transcriptional activity of NF-κB. These findings suggest that PRC is a negative regulator of endothelial inflammation.

  5. AMP-activated protein kinase is required for exercise-induced peroxisome proliferator-activated receptor co-activator 1 translocation to subsarcolemmal mitochondria in skeletal muscle.

    PubMed

    Smith, Brennan K; Mukai, Kazutaka; Lally, James S; Maher, Amy C; Gurd, Brendon J; Heigenhauser, George J F; Spriet, Lawrence L; Holloway, Graham P

    2013-03-15

    In skeletal muscle, mitochondria exist as two subcellular populations known as subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria. SS mitochondria preferentially respond to exercise training, suggesting divergent transcriptional control of the mitochondrial genomes. The transcriptional co-activator peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and mitochondrial transcription factor A (Tfam) have been implicated in the direct regulation of the mitochondrial genome in mice, although SS and IMF differences may exist, and the potential signalling events regulating the mitochondrial content of these proteins have not been elucidated. Therefore, we examined the potential for PGC-1α and Tfam to translocate to SS and IMF mitochondria in human subjects, and performed experiments in rodents to identify signalling mechanisms regulating these translocation events. Acute exercise in humans and rats increased PGC-1α content in SS but not IMF mitochondria. Acute exposure to 5-aminoimidazole-4-carboxamide-1-β-ribofuranoside in rats recapitulated the exercise effect of increased PGC-1α protein within SS mitochondria only, suggesting that AMP-activated protein kinase (AMPK) signalling is involved. In addition, rendering AMPK inactive (AMPK kinase dead mice) prevented exercise-induced PGC-1α translocation to SS mitochondria, further suggesting that AMPK plays an integral role in these translocation events. In contrast to the conserved PGC-1α translocation to SS mitochondria across species (humans, rats and mice), acute exercise only increased mitochondrial Tfam in rats. Nevertheless, in rat resting muscle PGC-1α and Tfam co-immunoprecipate with α-tubulin, suggesting a common cytosolic localization. These data suggest that exercise causes translocation of PGC-1α preferentially to SS mitochondria in an AMPK-dependent manner.

  6. ETS (E26 transformation-specific) up-regulation of the transcriptional co-activator TAZ promotes cell migration and metastasis in prostate cancer.

    PubMed

    Liu, Chen-Ying; Yu, Tong; Huang, Yuji; Cui, Long; Hong, Wanjin

    2017-06-02

    Prostate cancer is a very common malignant disease and a leading cause of death for men in the Western world. Tumorigenesis and progression of prostate cancer involves multiple signaling pathways, including the Hippo pathway. Yes-associated protein (YAP) is the downstream transcriptional co-activator of the Hippo pathway, is overexpressed in prostate cancer, and plays a vital role in the tumorigenesis and progression of prostate cancer. However, the role of the YAP paralog and another downstream effector of the Hippo pathway, transcriptional co-activator with PDZ-binding motif (TAZ), in prostate cancer has not been fully elucidated. Here, we show that TAZ is a basal cell marker for the prostate epithelium. We found that overexpression of TAZ promotes the epithelial-mesenchymal transition (EMT), cell migration, and anchorage-independent growth in the RWPE1 prostate epithelial cells. Of note, knock down of TAZ in the DU145 prostate cancer cells inhibited cell migration and metastasis. We also found that SH3 domain binding protein 1 (SH3BP1), a RhoGAP protein that drives cell motility, is a direct target gene of TAZ in the prostate cancer cells, mediating TAZ function in enhancing cell migration. Moreover, the prostate cancer-related oncogenic E26 transformation-specific (ETS) transcription factors, ETV1, ETV4, and ETV5, were required for TAZ gene transcription in PC3 prostate cancer cells. MAPK inhibitor U0126 treatment decreased TAZ expression in RWPE1 cells, and ETV4 overexpression rescued TAZ expression in RWPE1 cells with U0126 treatment. Our results show a regulatory mechanism of TAZ transcription and suggest a significant role for TAZ in the progression of prostate cancer. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Curcumin regulates peroxisome proliferator-activated receptor-γ coactivator-1α expression by AMPK pathway in hepatic stellate cells in vitro.

    PubMed

    Zhai, Xuguang; Qiao, Haowen; Guan, Wei; Li, Ziqiang; Cheng, Yuanyuan; Jia, Xin; Zhou, Yajun

    2015-01-05

    Curcumin exerts an inhibitory effect on hepatic stellate cell (HSC) activation, a key step for liver fibrogenesis, and on liver fibrosis by up-regulation of peroxisome proliferator-activated receptor-γ (PPARγ) expression. PPARγ plays a crucial role in suppression of HSC activation. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) functions as a co-activator for PPARγ. Therefore, researches on the effect of curcumin on PGC-1α might contribute to understanding of the mechanisms underlying curcumin inhibition of HSC activation and liver fibrosis through PPARγ. The present study aimed to investigate the effect of curcumin on PGC-1α expression in HSCs in vitro and examine the underlying molecular mechanisms by western blot, reat-time PCR, and transfection. Our results showed that curcumin stimulation increased PGC-1α expression and the effects of curcumin on PGC-1α expression were correlated with the activation of adenosine monophosphate-activated protein kinase (AMPK). Curcumin increased superoxide dimutase-2 (SOD2) transcription and activity by AMPK/PGC-1α axis. Moreover, PGC-1α was demonstrated to inhibit α1(I) collagen (a marker for liver fibrosis) transcription in cultured HSCs. These results demonstrated the promotion effect of curcumin on PGC-1α expression through AMPK pathway, which led to the increases in PPARγ activity and in SOD-2 transcription and activity. These data might suggest a possible new explanation for the inhibitory effect of curcumin on HSC activation and on liver fibrogenesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Children's Empowerment in Play

    ERIC Educational Resources Information Center

    Canning, Natalie

    2007-01-01

    This article examines the level of empowerment and autonomy children can create in their play experiences. It examines the play discourses that children build and maintain and considers the importance of play contexts in supporting children's emotional and social development. These aspects of play are often unseen or misunderstood by the adult…

  9. The Play of Psychotherapy

    ERIC Educational Resources Information Center

    Marks-Tarlow, Terry

    2012-01-01

    The author reviews the role of play within psychotherapy. She does not discuss the formal play therapy especially popular for young children, nor play from the Jungian perspective that encourages the use of the sand tray with adults. Instead, she focuses on the informal use of play during psychotherapy as it is orchestrated intuitively. Because…

  10. Two people playing together: some thoughts on play, playing, and playfulness in psychoanalytic work.

    PubMed

    Vliegen, Nicole

    2009-01-01

    Children's play and the playfulness of adolescents and adults are important indicators of personal growth and development. When a child is not able to play, or an adolescent/adult is not able to be playful with thoughts and ideas, psychotherapy can help to find a more playful and creative stance. Elaborating Winnicott's (1968, p. 591) statement that "psychotherapy has to do with two people playing together," three perspectives on play in psychotherapy are discussed. In the first point of view, the child gets in touch with and can work through aspects of his or her inner world, while playing in the presence of the therapist. The power of play is then rooted in the playful communication with the self In a second perspective, in play the child is communicating aspects of his or her inner world to the therapist as a significant other. In a third view, in "playing together" child and therapist are coconstructing new meanings. These three perspectives on play are valid at different moments of a therapy process or for different children, depending on the complex vicissitudes of the child's constitution, life experiences, development, and psychic structure. Concerning these three perspectives, a parallel can be drawn between the therapist's attitude toward the child's play and the way the therapist responds to the verbal play of an adolescent or adult. We illustrate this with the case of Jacob, a late adolescent hardly able to play with ideas.

  11. Expression of glucocorticoid receptor and coactivators in ependymal cells of male rats.

    PubMed

    Iwata, Kinuyo; Ozawa, Hitoshi

    2014-08-29

    Glucocorticoid receptor (GR) is a ligand-activated nuclear receptor which is widely distributed in the brain. Many types of neurons and glial cells are known to express GR, but the expression of GR in ependymal cells has yet to be identified. The present study therefore was undertaken to determine whether ependymal cells express GR and coactivators of GR, such as steroid receptor coactivator 1 (SRC-1) and p300. GR immunoreactivity was found in cells immunopositive to vimentin, a marker of ependymal cells, around the third ventricle (3V), the lateral ventricle (LV), the cerebral aqueduct and the fourth ventricle (4V), whereas the expression of GR in vimentin-immunoreactive (ir) cells was significantly reduced by adrenalectomy (ADX) in male rats. Vimentin-ir cells also expressed both SRC-1 and p300 at around 3V, LV, the cerebral aqueduct and 4V. ADX had no effect on the expression of SRC-1 or p300 in vimentin-ir cells. These results suggest that glucocorticoid may exert effects on ependymal cells through binding to GR followed by association with SRC-1 and p300 to maintain brain environment under stressful conditions.

  12. Coactivator SRC-2-dependent metabolic reprogramming mediates prostate cancer survival and metastasis.

    PubMed

    Dasgupta, Subhamoy; Putluri, Nagireddy; Long, Weiwen; Zhang, Bin; Wang, Jianghua; Kaushik, Akash K; Arnold, James M; Bhowmik, Salil K; Stashi, Erin; Brennan, Christine A; Rajapakshe, Kimal; Coarfa, Cristian; Mitsiades, Nicholas; Ittmann, Michael M; Chinnaiyan, Arul M; Sreekumar, Arun; O'Malley, Bert W

    2015-03-02

    Metabolic pathway reprogramming is a hallmark of cancer cell growth and survival and supports the anabolic and energetic demands of these rapidly dividing cells. The underlying regulators of the tumor metabolic program are not completely understood; however, these factors have potential as cancer therapy targets. Here, we determined that upregulation of the oncogenic transcriptional coregulator steroid receptor coactivator 2 (SRC-2), also known as NCOA2, drives glutamine-dependent de novo lipogenesis, which supports tumor cell survival and eventual metastasis. SRC-2 was highly elevated in a variety of tumors, especially in prostate cancer, in which SRC-2 was amplified and overexpressed in 37% of the metastatic tumors evaluated. In prostate cancer cells, SRC-2 stimulated reductive carboxylation of α-ketoglutarate to generate citrate via retrograde TCA cycling, promoting lipogenesis and reprogramming of glutamine metabolism. Glutamine-mediated nutrient signaling activated SRC-2 via mTORC1-dependent phosphorylation, which then triggered downstream transcriptional responses by coactivating SREBP-1, which subsequently enhanced lipogenic enzyme expression. Metabolic profiling of human prostate tumors identified a massive increase in the SRC-2-driven metabolic signature in metastatic tumors compared with that seen in localized tumors, further implicating SRC-2 as a prominent metabolic coordinator of cancer metastasis. Moreover, SRC-2 inhibition in murine models severely attenuated the survival, growth, and metastasis of prostate cancer. Together, these results suggest that the SRC-2 pathway has potential as a therapeutic target for prostate cancer.

  13. Functional interaction of nuclear receptor coactivator 4 with aryl hydrocarbon receptor

    SciTech Connect

    Kollara, Alexandra; Brown, Theodore J. . E-mail: brown@mshri.on.ca

    2006-07-28

    Aryl hydrocarbon receptor (AhR) transcriptional activity is enhanced by interaction with p160 coactivators. We demonstrate here that NcoA4, a nuclear receptor coactivator, interacts with and amplifies AhR action. NcoA4-AhR and NcoA4-ARNT interactions were demonstrated by immunoprecipitation in T47D breast cancer and COS cells and was independent of ligand. Overexpression of NcoA4 enhanced AhR transcriptional activity 3.2-fold in the presence of dioxin, whereas overexpression of a splice variant, NcoA4{beta}, as well as a variant lacking the C-terminal region enhanced AhR transcriptional activity by only 1.6-fold. Enhanced AhR signaling by NcoA4 was independent of the LXXLL and FXXLF motifs or of the activation domain. NcoA4 protein localized to cytoplasm in the absence of dioxin and in both the cytoplasm and nucleus following dioxin treatment. NcoA4-facilitation of AhR activity was abolished by overexpression of androgen receptor, suggesting a potential competition of AhR and androgen receptor for NcoA4. These findings thus demonstrate a functional interaction between NcoA4 and AhR that may alter AhR activity to affect disease development and progression.

  14. Epidermal growth factor increases coactivation of the androgen receptor in recurrent prostate cancer.

    PubMed

    Gregory, Christopher W; Fei, Xiaoyin; Ponguta, Liliana A; He, Bin; Bill, Heather M; French, Frank S; Wilson, Elizabeth M

    2004-02-20

    Growth of normal and neoplastic prostate is mediated by the androgen receptor (AR), a ligand-dependent transcription factor activated by high affinity androgen binding. The AR is highly expressed in recurrent prostate cancer cells that proliferate despite reduced circulating androgen. In this report, we show that epidermal growth factor (EGF) increases androgen-dependent AR transactivation in the recurrent prostate cancer cell line CWR-R1 through a mechanism that involves a post-transcriptional increase in the p160 coactivator transcriptional intermediary factor 2/glucocorticoid receptor interacting protein 1 (TIF2/GRIP1). Site-specific mutagenesis and selective MAPK inhibitors linked the EGF-induced increase in AR transactivation to phosphorylation of TIF2/GRIP1. EGF signaling increased the coimmunoprecipitation of TIF2 and AR. AR transactivation and its stimulation by EGF were reduced by small interfering RNA inhibition of TIF2/GRIP1 expression. The data indicate that EGF signaling through MAPK increases TIF2/GRIP1 coactivation of AR transactivation in recurrent prostate cancer.

  15. The impact of language co-activation on L1 and L2 speech fluency.

    PubMed

    Bergmann, Christopher; Sprenger, Simone A; Schmid, Monika S

    2015-10-01

    Fluent speech depends on the availability of well-established linguistic knowledge and routines for speech planning and articulation. A lack of speech fluency in late second-language (L2) learners may point to a deficiency of these representations, due to incomplete acquisition. Experiments on bilingual language processing have shown, however, that there are strong reasons to believe that multilingual speakers experience co-activation of the languages they speak. We have studied to what degree language co-activation affects fluency in the speech of bilinguals, comparing a monolingual German control group with two bilingual groups: 1) first-language (L1) attriters, who have fully acquired German before emigrating to an L2 English environment, and 2) immersed L2 learners of German (L1: English). We have analysed the temporal fluency and the incidence of disfluency markers (pauses, repetitions and self-corrections) in spontaneous film retellings. Our findings show that learners to speak more slowly than controls and attriters. Also, on each count, the speech of at least one of the bilingual groups contains more disfluency markers than the retellings of the control group. Generally speaking, both bilingual groups-learners and attriters-are equally (dis)fluent and significantly more disfluent than the monolingual speakers. Given that the L1 attriters are unaffected by incomplete acquisition, we interpret these findings as evidence for language competition during speech production. Copyright © 2015. Published by Elsevier B.V.

  16. Novel CARM1-Interacting Protein, DZIP3, Is a Transcriptional Coactivator of Estrogen Receptor-α

    PubMed Central

    Purcell, Daniel J.; Chauhan, Swati; Jimenez-Stinson, Diane; Elliott, Kathleen R.; Tsewang, Tenzin D.; Lee, Young-Ho; Marples, Brian

    2015-01-01

    Coactivator-associated arginine methyltransferase 1 (CARM1) is known to promote estrogen receptor (ER)α-mediated transcription in breast cancer cells. To further characterize the regulation of ERα-mediated transcription by CARM1, we screened CARM1-interacting proteins by yeast two-hybrid. Here, we have identified an E3 ubiquitin ligase, DAZ (deleted in azoospermia)-interacting protein 3 (DZIP3), as a novel CARM1-binding protein. DZIP3-dependent ubiquitination of histone H2A has been associated with repression of transcription. However, ERα reporter gene assays demonstrated that DZIP3 enhanced ERα-mediated transcription and cooperated synergistically with CARM1. Interaction with CARM1 was observed with the E3 ligase RING domain of DZIP3. The methyltransferase activity of CARM1 partially contributed to the synergy with DZIP3 for transcription activation, but the E3 ubiquitin ligase activity of DZIP3 was dispensable. DZIP3 also interacted with the C-terminal activation domain 2 of glucocorticoid receptor-interacting protein 1 (GRIP1) and enhanced the interaction between GRIP1 and CARM1. Depletion of DZIP3 by small interfering RNA in MCF7 cells reduced estradiol-induced gene expression of ERα target genes, GREB1 and pS2, and DZIP3 was recruited to the estrogen response elements of the same ERα target genes. These results indicate that DZIP3 is a novel coactivator of ERα target gene expression. PMID:26505218

  17. Olympic weightlifting training causes different knee muscle-coactivation adaptations compared with traditional weight training.

    PubMed

    Arabatzi, Fotini; Kellis, Eleftherios

    2012-08-01

    The purpose of this study was to compare the effects of an Olympic weightlifting (OL) and traditional weight (TW) training program on muscle coactivation around the knee joint during vertical jump tests. Twenty-six men were assigned randomly to 3 groups: the OL (n = 9), the TW (n = 9), and Control (C) groups (n = 8). The experimental groups trained 3 d · wk(-1) for 8 weeks. Electromyographic (EMG) activity from the rectus femoris and biceps femoris, sagittal kinematics, vertical stiffness, maximum height, and power were collected during the squat jump, countermovement jump (CMJ), and drop jump (DJ), before and after training. Knee muscle coactivation index (CI) was calculated for different phases of each jump by dividing the antagonist EMG activity by the agonist. Analysis of variance showed that the CI recorded during the preactivation and eccentric phases of all the jumps increased in both training groups. The OL group showed a higher stiffness and jump height adaptation than the TW group did (p < 0.05). Further, the OL showed a decrease or maintenance of the CI recorded during the propulsion phase of the CMJ and DJs, which is in contrast to the increase in the CI observed after TW training (p < 0.05). The results indicated that the altered muscle activation patterns about the knee, coupled with changes of leg stiffness, differ between the 2 programs. The OL program improves jump performance via a constant CI, whereas the TW training caused an increased CI, probably to enhance joint stability.

  18. Motor co-activation in siblings of patients with juvenile myoclonic epilepsy: an imaging endophenotype?

    PubMed Central

    Wandschneider, Britta; Centeno, Maria; Vollmar, Christian; Symms, Mark; Thompson, Pamela J.; Duncan, John S.

    2014-01-01

    Juvenile myoclonic epilepsy is a heritable idiopathic generalized epilepsy syndrome, characterized by myoclonic jerks and frequently triggered by cognitive effort. Impairment of frontal lobe cognitive functions has been reported in patients with juvenile myoclonic epilepsy and their unaffected siblings. In a recent functional magnetic resonance imaging study we reported abnormal co-activation of the motor cortex and increased functional connectivity between the motor system and prefrontal cognitive networks during a working memory paradigm, providing an underlying mechanism for cognitively triggered jerks. In this study, we used the same task in 15 unaffected siblings (10 female; age range 18–65 years, median 40) of 11 of those patients with juvenile myoclonic epilepsy (six female; age range 22–54 years, median 35) and compared functional magnetic resonance imaging activations with 20 age- and gender-matched healthy control subjects (12 female; age range 23–46 years, median 30.5). Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to patients (P < 0.001 uncorrected; 20-voxel threshold extent). This finding in unaffected siblings suggests that altered motor system activation and functional connectivity is not medication- or seizure-related, but represents a potential underlying mechanism for impairment of frontal lobe functions in both patients and siblings, and so constitutes an endophenotype of juvenile myoclonic epilepsy. PMID:25001494

  19. SRC-2-mediated coactivation of anti-tumorigenic target genes suppresses MYC-induced liver cancer

    PubMed Central

    Zhou, Xiaorong; Comerford, Sarah A.; York, Brian; O’Donnell, Kathryn A.

    2017-01-01

    Hepatocellular carcinoma (HCC) is the fifth most common solid tumor in the world and the third leading cause of cancer-associated deaths. A Sleeping Beauty-mediated transposon mutagenesis screen previously identified mutations that cooperate with MYC to accelerate liver tumorigenesis. This revealed a tumor suppressor role for Steroid Receptor Coactivator 2/Nuclear Receptor Coactivator 2 (Src-2/Ncoa2) in liver cancer. In contrast, SRC-2 promotes survival and metastasis in prostate cancer cells, suggesting a tissue-specific and context-dependent role for SRC-2 in tumorigenesis. To determine if genetic loss of SRC-2 is sufficient to accelerate MYC-mediated liver tumorigenesis, we bred Src-2-/- mice with a MYC-induced liver tumor model and observed a significant increase in liver tumor burden. RNA sequencing of liver tumors and in vivo chromatin immunoprecipitation assays revealed a set of direct target genes that are bound by SRC-2 and exhibit downregulated expression in Src-2-/- liver tumors. We demonstrate that activation of SHP (Small Heterodimer Partner), DKK4 (Dickkopf-4), and CADM4 (Cell Adhesion Molecule 4) by SRC-2 suppresses tumorigenesis in vitro and in vivo. These studies suggest that SRC-2 may exhibit oncogenic or tumor suppressor activity depending on the target genes and nuclear receptors that are expressed in distinct tissues and illuminate the mechanisms of tumor suppression by SRC-2 in liver. PMID:28273073

  20. Statins enhance peroxisome proliferator-activated receptor gamma coactivator-1alpha activity to regulate energy metabolism.

    PubMed

    Wang, Wenxian; Wong, Chi-Wai

    2010-03-01

    Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) serves as an inducible coactivator for a number of transcription factors to control energy metabolism. Insulin signaling through Akt kinase has been demonstrated to phosphorylate PGC-1alpha at serine 571 and downregulate its activity in the liver. Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors that reduce cholesterol synthesis in the liver. In this study, we found that statins reduced the active form of Akt and enhanced PGC-1alpha activity. Specifically, statins failed to activate an S571A mutant of PGC-1alpha. The activation of PGC-1alpha by statins selectively enhanced the expression of energy metabolizing enzymes and regulators including peroxisome proliferator-activated receptor alpha, acyl-CoA oxidase, carnitine palmitoyl transferase-1A, and pyruvate dehydrogenase kinase 4. Importantly, a constitutively active form of Akt partially reduced the statin-enhanced gene expression. Our study thus provides a plausible mechanistic explanation for the hypolipidemic effect of statin through elevating the rate of beta-oxidation and mitochondrial Kreb's cycle capacity to enhance fatty acid utilization while reducing the rate of glycolysis.

  1. Implicit co-activation of American Sign Language in deaf readers: An ERP study.

    PubMed

    Meade, Gabriela; Midgley, Katherine J; Sevcikova Sehyr, Zed; Holcomb, Phillip J; Emmorey, Karen

    2017-07-01

    In an implicit phonological priming paradigm, deaf bimodal bilinguals made semantic relatedness decisions for pairs of English words. Half of the semantically unrelated pairs had phonologically related translations in American Sign Language (ASL). As in previous studies with unimodal bilinguals, targets in pairs with phonologically related translations elicited smaller negativities than targets in pairs with phonologically unrelated translations within the N400 window. This suggests that the same lexicosemantic mechanism underlies implicit co-activation of a non-target language, irrespective of language modality. In contrast to unimodal bilingual studies that find no behavioral effects, we observed phonological interference, indicating that bimodal bilinguals may not suppress the non-target language as robustly. Further, there was a subset of bilinguals who were aware of the ASL manipulation (determined by debrief), and they exhibited an effect of ASL phonology in a later time window (700-900ms). Overall, these results indicate modality-independent language co-activation that persists longer for bimodal bilinguals. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Defective co-activator recruitment in osteoclasts from microphthalmia-oak ridge mutant mice.

    PubMed

    Sharma, Sudarshana M; Sif, Said; Ostrowski, Michael C; Sankar, Uma

    2009-07-01

    The three basic DNA-binding domain mutations of the microphthalmia-associated transcription factor (Mitf), Mitf(mi/mi), Mitf(or/or), and Mitf(wh/wh) affect osteoclast differentiation with variable penetrance while completely impairing melanocyte development. Mitf(or/or) mice exhibit osteopetrosis that improves with age and their osteoclasts form functional multinuclear osteoclasts, raising the question as to why the Mitf(or/or) mutation results in osteopetrosis. Here we show that Mitf(or/or) osteoclasts express normal levels of acid phosphatase 5 (Acp5) mRNA and significantly lower levels of Cathepsin K (Ctsk) mRNA during receptor activator of nuclear factor kappa B (NFkappaB) ligand (RANKL)-mediated differentiation. Studies using chromatin immunoprecipitation (ChIP) analysis indicate that low levels of Mitf(or/or) protein are recruited to the Ctsk promoter. However, enrichment of Mitf-transcriptional co-activators PU.1 and Brahma-related gene 1 (Brg1) are severely impaired at the Ctsk promoter of Mitf(or/or) osteoclast precursors, indicating that defective recruitment of co-activators by the mutant Mitf(or/or) results in impaired Ctsk expression in osteoclasts. Cathepsin K may thus represent a unique class of Mitf-regulated osteoclast-specific genes that are important for osteoclast function.

  3. The CREB coactivator CRTC2 controls hepatic lipid metabolism by regulating SREBP1.

    PubMed

    Han, Jinbo; Li, Erwei; Chen, Liqun; Zhang, Yuanyuan; Wei, Fangchao; Liu, Jieyuan; Deng, Haiteng; Wang, Yiguo

    2015-08-13

    Abnormal accumulation of triglycerides in the liver, caused in part by increased de novo lipogenesis, results in non-alcoholic fatty liver disease and insulin resistance. Sterol regulatory element-binding protein 1 (SREBP1), an important transcriptional regulator of lipogenesis, is synthesized as an inactive precursor that binds to the endoplasmic reticulum (ER). In response to insulin signalling, SREBP1 is transported from the ER to the Golgi in a COPII-dependent manner, processed by proteases in the Golgi, and then shuttled to the nucleus to induce lipogenic gene expression; however, the mechanisms underlying enhanced SREBP1 activity in insulin-resistant obesity and diabetes remain unclear. Here we show in mice that CREB regulated transcription coactivator 2 (CRTC2) functions as a mediator of mTOR signalling to modulate COPII-dependent SREBP1 processing. CRTC2 competes with Sec23A, a subunit of the COPII complex, to interact with Sec31A, another COPII subunit, thus disrupting SREBP1 transport. During feeding, mTOR phosphorylates CRTC2 and attenuates its inhibitory effect on COPII-dependent SREBP1 maturation. As hepatic overexpression of an mTOR-defective CRTC2 mutant in obese mice improved the lipogenic program and insulin sensitivity, these results demonstrate how the transcriptional coactivator CRTC2 regulates mTOR-mediated lipid homeostasis in the fed state and in obesity.

  4. The function of steroid receptor coactivator-1 in normal tissues and cancer.

    PubMed

    Walsh, Claire A; Qin, Li; Tien, Jean Ching-Yi; Young, Leonie S; Xu, Jianming

    2012-01-01

    In 1995, the steroid receptor coactivator-1 (SRC-1) was identified as the first authentic steroid receptor coactivator. Since then, the SRC proteins have remained at the epicenter of coregulator biology, molecular endocrinology and endocrine-related cancer. Cumulative works on SRC-1 have shown that it is primarily a nuclear receptor coregulator and functions to construct highly specific enzymatic protein complexes which can execute efficient and successful transcriptional activation of designated target genes. The versatile nature of SRC-1 enables it to respond to steroid dependent and steroid independent stimulation, allowing it to bind across many families of transcription factors to orchestrate and regulate complex physiological reactions. This review highlights the multiple functions of SRC-1 in the development and maintenance of normal tissue functions as well as its major role in mediating hormone receptor responsiveness. Insights from genetically manipulated mouse models and clinical data suggest SRC-1 is significantly overexpressed in many cancers, in particular, cancers of the reproductive tissues. SRC-1 has been associated with cellular proliferation and tumor growth but its major tumorigenic contributions are promotion and execution of breast cancer metastasis and mediation of resistance to endocrine therapies. The ability of SRC-1 to coordinate multiple signaling pathways makes it an important player in tumor cells' escape of targeted therapy.

  5. A Transcription Factor-Binding Domain of the Coactivator CBP Is Essential for Long-Term Memory and the Expression of Specific Target Genes

    ERIC Educational Resources Information Center

    Oliveira, Ana M. M.; Brindle, Paul K.; Abel, Ted; Wood, Marcelo A.; Attner, Michelle A.

    2006-01-01

    Transcriptional activation is a key process required for long-term memory formation. Recently, the transcriptional coactivator CREB-binding protein (CBP) was shown to be critical for hippocampus-dependent long-term memory and hippocampal synaptic plasticity. As a coactivator with intrinsic histone acetyltransferase activity, CBP interacts with…

  6. Metoclopramide as pharmacological tool to assess vasopressinergic co-activation of the hypothalamus-pituitary-adrenal (HPA) axis: a study in healthy volunteers.

    PubMed

    Jacobs, G E; Hulskotte, E G J; de Kam, M L; Zha, G; Jiang, J; Hu, P; Zhao, Q; van Pelt, J; Goekoop, J G; Zitman, F G; van Gerven, J M A

    2010-12-01

    The synthetic vasopressin (AVP) analogue desmopressin (dDAVP) has been used as pharmacological function test to quantify vasopressinergic co-activation of the hypothalamus-pituitary-adrenal (HPA) axis in the past. Such exogenous vasopressinergic stimulation may induce confounding cardiovascular, pro-coagulatory and anti-diuretic effects and low endogenous corticotrophin-releasing-hormone (CRH) levels may limit its potential to reliably assess co-activation. Alternatively, the dopamine-2-(D2)-antagonist metoclopramide is believed to induce co-activation indirectly by releasing endogenous AVP. We investigated this indirect co-activation with metoclopramide under conditions of low and enhanced endogenous CRH release in healthy volunteers. A randomized, double-blind, placebo-controlled, four-way crossover study was performed in 12 healthy males. CRH release was induced by administering an oral 5-hydroxytryptophan (5-HTP) 200 mg function test. Co-activation was investigated by administering metoclopramide 10mg intravenously around the expected maximal effect of 5-HTP. The neuroendocrine effects were compared to those of metoclopramide alone, the 5-HTP test alone and matching placebo. Metoclopramide safely induced HPA-axis activation by itself, and potently synergized 5-HTP-induced corticotrophinergic activation of the HPA axis. These findings are indicative of vasopressinergic co-activation and suggest a role for metoclopramide as a practical function test for co-activation of the HPA axis. However, its application will be hampered pending clarification of the exact pharmacological mechanism by which metoclopramide induces co-activation of the HPA axis.

  7. A Transcription Factor-Binding Domain of the Coactivator CBP Is Essential for Long-Term Memory and the Expression of Specific Target Genes

    ERIC Educational Resources Information Center

    Oliveira, Ana M. M.; Brindle, Paul K.; Abel, Ted; Wood, Marcelo A.; Attner, Michelle A.

    2006-01-01

    Transcriptional activation is a key process required for long-term memory formation. Recently, the transcriptional coactivator CREB-binding protein (CBP) was shown to be critical for hippocampus-dependent long-term memory and hippocampal synaptic plasticity. As a coactivator with intrinsic histone acetyltransferase activity, CBP interacts with…

  8. Role-Playing Mitosis.

    ERIC Educational Resources Information Center

    Wyn, Mark A.; Stegink, Steven J.

    2000-01-01

    Introduces a role playing activity that actively engages students in the learning process of mitosis. Students play either chromosomes carrying information, or cells in the cell membrane. (Contains 11 references.) (Author/YDS)

  9. Role-Playing Mitosis.

    ERIC Educational Resources Information Center

    Wyn, Mark A.; Stegink, Steven J.

    2000-01-01

    Introduces a role playing activity that actively engages students in the learning process of mitosis. Students play either chromosomes carrying information, or cells in the cell membrane. (Contains 11 references.) (Author/YDS)

  10. Playing It Right

    ERIC Educational Resources Information Center

    Tooley, Kay

    1973-01-01

    Described is one technique, referred to as "playing it right," to aid the therapist in the treatment of borderline children. "Playing it right" is based on the introduction of reality rules into the fantasy world of the borderline child. (CS)

  11. Co-activator candidate interactions for orphan nuclear receptor NR2E1.

    PubMed

    Corso-Díaz, Ximena; de Leeuw, Charles N; Alonso, Vivian; Melchers, Diana; Wong, Bibiana K Y; Houtman, René; Simpson, Elizabeth M

    2016-10-26

    NR2E1 (Tlx) is an orphan nuclear receptor that regulates the maintenance and self-renewal of neural stem cells, and promotes tumourigenesis. Nr2e1-null mice exhibit reduced cortical and limbic structures and pronounced retinal dystrophy. NR2E1 functions mainly as a repressor of gene transcription in association with the co-repressors atrophin-1, LSD1, HDAC and BCL11A. Recent evidence suggests that NR2E1 also acts as an activator of gene transcription. However, co-activator complexes that interact with NR2E1 have not yet been identified. In order to find potential novel co-regulators for NR2E1, we used a microarray assay for real-time analysis of co-regulator-nuclear receptor interaction (MARCoNI) that contains peptides representing interaction motifs from potential co-regulatory proteins, including known co-activator nuclear receptor box sequences (LxxLL motif). We found that NR2E1 binds strongly to an atrophin-1 peptide (Atro box) used as positive control and to 19 other peptides that constitute candidate NR2E1 partners. Two of these proteins, p300 and androgen receptor (AR), were further validated by reciprocal pull-down assays. The specificity of NR2E1 binding to peptides in the array was evaluated using two single amino acid variants, R274G and R276Q, which disrupted the majority of the binding interactions observed with wild-type NR2E1. The decreased binding affinity of these variants to co-regulators was further validated by pull-down assays using atrophin1 as bait. Despite the high conservation of arginine 274 in vertebrates, its reduced interactions with co-regulators were not significant in vivo as determined by retinal phenotype analysis in single-copy Nr2e1-null mice carrying the variant R274G. We showed that MARCoNI is a specific assay to test interactions of NR2E1 with candidate co-regulators. In this way, we unveiled 19 potential co-regulator partners for NR2E1, including eight co-activators. All the candidates here identified need to be further

  12. Playful "Moments" in Psychotherapy

    ERIC Educational Resources Information Center

    Terr, Lenore C.; Deeney, John M.; Drell, Martin; Dodson, Jerry W.; Gaensbauer, Theodore J.; Massie, Henry; Minde, Klaus; Stewart, George; Teal, Stewart; Winters, Nancy C.

    2006-01-01

    This article demonstrates how taking the time out to play, commenting pungently on play, serving up surprise and adventure, and developing mutually understood codes or inside jokes help the psychiatrist to turn a child around. In this article, the authors categorized what principles of treatment their 10 vignettes about playfulness illustrated,…

  13. The Pedagogy of Play

    ERIC Educational Resources Information Center

    Giesbrecht, Sheila

    2012-01-01

    Play is important. Environmental educators Sobel and Louv write about the relationship between children and outside play and suggest that early transcendental experiences within nature allow children to develop empathetic orientations towards the natural world. Children who play out-of-doors develop an appreciation for the environment and…

  14. Life! Through Play.

    ERIC Educational Resources Information Center

    Van Anne, Nancy

    This speech presents a review of research concerning the nature of play. Some of the formal characteristics of play are: (a) it is distinct from ordinary life in its "temporariness" and its limitless location; (b) there is an element of tension in play that leads to uncertainty concerning the outcome but at the same time provides the opportunity…

  15. The Excellence of Play.

    ERIC Educational Resources Information Center

    Moyles, Janet R., Ed.

    Recognizing that for young children, play is a tool for learning, this book compiles contributions by different authors, reflecting both up-to-date research and current classroom practice as they relate to children's play. Part 1 of the book explores the value of play as a cross-cultural concept as well as one rooted in the Western world. Gender…

  16. Playing against the Game

    ERIC Educational Resources Information Center

    Remmele, Bernd

    2017-01-01

    The paper first outlines a differentiation of play/game-motivations that include "negative" attitudes against the play/game itself like cheating or spoilsporting. This problem is of particular importance in concern of learning games because they are not "played" for themselves--at least in the first place--but due to an…

  17. The Importance of Play.

    ERIC Educational Resources Information Center

    Sher, Allen

    Play is the spontaneous or organized recreational activity of children; it is at the heart of the preschool curriculum. Play aids in the development of physical, intellectual, and social skills. Children's play progresses through three developmental stages: solitary, parallel, and social. Preschool teachers should arrange for four kinds of…

  18. Outdoor Creative Play Areas.

    ERIC Educational Resources Information Center

    Miller, Peggy L.

    Guidelines are given for the development of outdoor play areas on school sites to provide children with natural areas and simple facilities for creative play. Site selection, analysis, and development are discussed. Natural, topographical features of the environment and natural play equipment are suggested. Illustrations are also presented to aid…

  19. Play Is the Way

    ERIC Educational Resources Information Center

    Gross, Steve; Sanderson, Rebecca Cornelli

    2012-01-01

    Historically, play has been viewed as a frivolous break from important endeavors like working and learning when, in fact, a child's ability to fully and freely engage in play is essential to their learning, productivity, and overall development. A natural drive to play is universal across all young mammals. Children from every society on earth…

  20. The Pedagogy of Play

    ERIC Educational Resources Information Center

    Giesbrecht, Sheila

    2012-01-01

    Play is important. Environmental educators Sobel and Louv write about the relationship between children and outside play and suggest that early transcendental experiences within nature allow children to develop empathetic orientations towards the natural world. Children who play out-of-doors develop an appreciation for the environment and…

  1. Play Is the Way

    ERIC Educational Resources Information Center

    Gross, Steve; Sanderson, Rebecca Cornelli

    2012-01-01

    Historically, play has been viewed as a frivolous break from important endeavors like working and learning when, in fact, a child's ability to fully and freely engage in play is essential to their learning, productivity, and overall development. A natural drive to play is universal across all young mammals. Children from every society on earth…

  2. Playful Teaching Practices

    ERIC Educational Resources Information Center

    Michaelis, Bill

    2005-01-01

    In physical education, playful teaching practices are essential to relationship building and creating "connections" for successful group dynamics. Perhaps most importantly, playful teachers develop positive attitudes in their students and help students understand that learning can be fun and joyful. Playful teaching practices also greatly enhance…

  3. Discovery of the First Irreversible Small Molecule Inhibitors of the Interaction between the Vitamin D Receptor and Coactivators

    PubMed Central

    Nandhikonda, Premchendar; Lynt, Wen Z.; McCallum, Megan M.; Ara, Tahniyath; Baranowski, Athena M.; Yuan, Nina Y.; Pearson, Dana; Bikle, Daniel D.; Guy, R. Kiplin; Arnold, Leggy A.

    2012-01-01

    The vitamin D receptor (VDR) is a nuclear hormone receptor that regulates cell proliferation, cell differentiation, and calcium homeostasis. The receptor is activated by vitamin D analogs that induce the disruption of VDR-corepressor binding and promote VDR-coactivator interactions. The interactions between VDR and coregulators are essential for VDR-mediated transcription. Small molecule inhibition of VDR–coregulator binding represents an alternative method to the traditional ligand-based approach in order to modulate the expression of VDR target genes. A high throughput fluorescence polarization screen that quantifies the inhibition of binding between VDR and a fluorescently labeled steroid receptor coactivator 2 peptide was applied to discover the new small molecule VDR–coactivator inhibitors, 3-indolyl-methanamines. Structure-activity relationship studies with 3-indolyl-methanamine analogs were used to determine their mode of VDR-binding and to produce the first VDR-selective and irreversible VDR–coactivator inhibitors with the ability to regulate the transcription of the human VDR target gene, TRPV6. PMID:22563729

  4. Lysine 246 of the vitamin D receptor is crucial for ligand-dependent interaction with coactivators and transcriptional activity.

    PubMed

    Jiménez-Lara, A M; Aranda, A

    1999-05-07

    Mutant K246A in the predicted helix 3 of the ligand-binding domain, as well as mutants L417S and E420Q in helix 12, which contains the core ligand-dependent transcriptional activation domain (AF-2), were generated to examine AF-2 activity of the vitamin D receptor (VDR). These mutations abolished vitamin D-dependent transactivation. In addition, VDR mediates a ligand-dependent repression of the response of the retinoic acid receptor beta2 promoter to retinoic acid, and the helix 3 and helix 12 mutants were unable to mediate transrepression. Furthermore, the VDR mutants, but not the native receptor, enhanced phorbol ester induction of the activator protein-1-containing collagenase promoter. The helix 3 and helix 12 mutations strikingly reduced the ability of VDR to interact with the coactivators steroid receptor coactivator-1, ACTR, and the CREB-binding protein. As a consequence, overexpression of steroid receptor coactivator-1 increased vitamin D-dependent transactivation by VDR but not by the K246A mutant. These results indicate that the lysine 246 participates, together with residues in helix 12, in the recruitment of coactivators and that AF-2 activity is involved both in ligand-dependent transactivation and in transrepression by VDR.

  5. African oil plays

    SciTech Connect

    Clifford, A.J. )

    1989-09-01

    The vast continent of Africa hosts over eight sedimentary basins, covering approximately half its total area. Of these basins, only 82% have entered a mature exploration phase, 9% have had little or no exploration at all. Since oil was first discovered in Africa during the mid-1950s, old play concepts continue to bear fruit, for example in Egypt and Nigeria, while new play concepts promise to become more important, such as in Algeria, Angola, Chad, Egypt, Gabon, and Sudan. The most exciting developments of recent years in African oil exploration are: (1) the Gamba/Dentale play, onshore Gabon; (2) the Pinda play, offshore Angola; (3) the Lucula/Toca play, offshore Cabinda; (4) the Metlaoui play, offshore Libya/Tunisia; (5) the mid-Cretaceous sand play, Chad/Sudan; and (6) the TAG-I/F6 play, onshore Algeria. Examples of these plays are illustrated along with some of the more traditional oil plays. Where are the future oil plays likely to develop No doubt, the Saharan basins of Algeria and Libya will feature strongly, also the presalt of Equatorial West Africa, the Central African Rift System and, more speculatively, offshore Ethiopia and Namibia, and onshore Madagascar, Mozambique, and Tanzania.

  6. A wrench-shaped synthetic molecule that modulates a transcription factor-coactivator interaction.

    PubMed

    Shimogawa, Hiroki; Kwon, Youngjoo; Mao, Qian; Kawazoe, Yoshinori; Choi, Yongmun; Asada, Shinichi; Kigoshi, Hideo; Uesugi, Motonari

    2004-03-24

    Development of synthetic molecules that provide external control over the transcription of a given gene represents a challenge in medicinal and bioorganic chemistry. Here we report design and analysis of wrenchnolol, a wrench-shaped synthetic molecule that impairs the transcription of the Her2 oncogene by disrupting association of transcription factor ESX with its coactivator Sur-2. The "jaw" part of the compound mimics the alpha-helical interface of the activation domain of ESX, and the "handle" region accepts chemical modifications for a range of analysis. A water-soluble handle permitted NMR study in aqueous solution; a biotinylated handle verified the selectivity of the interaction, and a fluorescent handle confirmed the cell permeability of the compound. The case study of wrenchnolol foreshadows the promise and the challenge of targeting protein-protein interactions in the nucleus and may lead to the development of unique synthetic modulators of gene transcription.

  7. Ankle antagonist coactivation in the double-support phase of walking: Stroke vs. healthy subjects.

    PubMed

    Silva, Augusta; Sousa, Andreia S P; Silva, Cláudia; Tavares, João Manuel R S; Santos, Rubim; Sousa, Filipa

    2015-01-01

    Lesions in ipsilateral systems related to postural control in the ipsilesional side may justify the lower performance of stroke subjects during walking. To analyze bilateral ankle antagonist coactivation during double support in stroke subjects. Sixteen (8 females; 8 males) subjects with a first isquemic stroke and 22 controls (12 females; 10 males) participated in this study. The double-support phase was assessed through ground reaction forces and the electromyography of ankle muscles was assessed in both limbs. The ipsilesional limb presented statistically significant differences from the control when assuming specific roles during double support. The tibialis anterior and soleus pair was the one in which this atypical behavior was more pronounced. The ipsilesional limb presents a dysfunctional behavior when a higher postural control activity was demanded.

  8. Human transcriptional coactivator PC4 stimulates DNA end joining and activates DSB repair activity.

    PubMed

    Batta, Kiran; Yokokawa, Masatoshi; Takeyasu, Kunio; Kundu, Tapas K

    2009-01-23

    Human transcriptional coactivator PC4 is a highly abundant nuclear protein that is involved in diverse cellular processes ranging from transcription to chromatin organization. Earlier, we have shown that PC4, a positive activator of p53, overexpresses upon genotoxic insult in a p53-dependent manner. In the present study, we show that PC4 stimulates ligase-mediated DNA end joining irrespective of the source of DNA ligase. Pull-down assays reveal that PC4 helps in the association of DNA ends through its C-terminal domain. In vitro nonhomologous end-joining assays with cell-free extracts show that PC4 enhances the joining of noncomplementary DNA ends. Interestingly, we found that PC4 activates double-strand break (DSB) repair activity through stimulation of DSB rejoining in vivo. Together, these findings demonstrate PC4 as an activator of nonhomologous end joining and DSB repair activity.

  9. Task-dependence of jaw elevator and depressor co-activation.

    PubMed

    Proeschel, P A; Raum, J

    2003-08-01

    Elevator muscle activity per unit bite-force has been shown to be higher in chewing than in isometric biting. We tested the hypothesis that surplus elevator activity is evoked in response to a possible co-activation of jaw-opener muscles during the masticatory power stroke. In 32 subjects, digastric and bilateral masseter and temporalis activities were recorded during unilateral chewing of test foods, isometric biting on a force transducer, and during balancing of the jaw against maximum effort of depressor muscles. During elevator peak effort in chewing, the digastric activity was 113% higher than during peak effort in isometric biting. Comparison of balancing and chewing trials revealed that a 6% increase of elevator activity would suffice to compensate for this increased depressor action. Elevator activity in chewing, however, was up to 130% higher than in clenching. We conclude that depressor counteraction could have only a minor influence on the generation of surplus muscle activity in chewing.

  10. 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

  11. Ash2 acts as an ecdysone receptor coactivator by stabilizing the histone methyltransferase Trr

    PubMed Central

    Carbonell, Albert; Mazo, Alexander; Serras, Florenci; Corominas, Montserrat

    2013-01-01

    The molting hormone ecdysone triggers chromatin changes via histone modifications that are important for gene regulation. On hormone activation, the ecdysone receptor (EcR) binds to the SET domain–containing histone H3 methyltransferase trithorax-related protein (Trr). Methylation of histone H3 at lysine 4 (H3K4me), which is associated with transcriptional activation, requires several cofactors, including Ash2. We find that ash2 mutants have severe defects in pupariation and metamorphosis due to a lack of activation of ecdysone-responsive genes. This transcriptional defect is caused by the absence of the H3K4me3 marks set by Trr in these genes. We present evidence that Ash2 interacts with Trr and is required for its stabilization. Thus we propose that Ash2 functions together with Trr as an ecdysone receptor coactivator. PMID:23197473

  12. Steroid receptor coactivator 3 regulates autophagy in breast cancer cells through macrophage migration inhibitory factor

    PubMed Central

    Wu, Mei-Yi; Fu, Junjiang; Xu, Jianming; O'Malley, Bert W; Wu, Ray-Chang

    2012-01-01

    SRC-3/AIB1 (steroid receptor coactivator 3/amplified in breast cancer 1) is an authentic oncogene that contributes to the development of drug resistance and poor disease-free survival in cancer patients. Autophagy is also an important cell death mechanism that has tumor suppressor function. In this study, we identified macrophage migration inhibitory factor (MIF) as a novel target gene of SRC-3 and demonstrated its importance in cell survival. Specifically, we showed that MIF is a strong suppressor of autophagic cell death. We further showed that suppression of MIF, in turn, induced autophagic cell death, enhanced chemosensitivity and inhibited tumorigenesis in a xenograft mouse tumorigenesis model. Our study demonstrated that regulation of MIF expression and suppression of autophagic cell death is a potent mechanism by which SRC-3 contributes to increased chemoresistance and tumorigenicity. PMID:22430150

  13. The steroid receptor coactivator, GRIP-1, is necessary for MEF-2C-dependent gene expression and skeletal muscle differentiation

    PubMed Central

    Chen, Shen Liang; Dowhan, Dennis H.; Hosking, Brett M.; Muscat, George E.O.

    2000-01-01

    Nuclear receptor-mediated activation of transcription involves coactivation by cofactors collectively denoted the steroid receptor coactivators (SRCs). The process also involves the subsequent recruitment of p300/CBP and PCAF to a complex that synergistically regulates transcription and remodels the chromatin. PCAF and p300 have also been demonstrated to function as critical coactivators for the muscle-specific basic helix–loop–helix (bHLH) protein MyoD during myogenic commitment. Skeletal muscle differentiation and the activation of muscle-specific gene expression is dependent on the concerted action of another bHLH factor, myogenin, and the MADS protein, MEF-2, which function in a cooperative manner. We examined the functional role of one SRC, GRIP-1, in muscle differentiation, an ideal paradigm for the analysis of the determinative events that govern the cell's decision to divide or differentiate. We observed that the mRNA encoding GRIP-1 is expressed in proliferating myoblasts and post-mitotic differentiated myotubes, and that protein levels increase during differentiation. Exogenous/ectopic expression studies with GRIP-1 sense and antisense vectors in myogenic C2C12 cells demonstrated that this SRC is necessary for (1) induction/activation of myogenin, MEF-2, and the crucial cell cycle regulator, p21, and (2) contractile protein expression and myotube formation. Furthermore, we demonstrate that the SRC GRIP-1 coactivates MEF-2C-mediated transcription. GRIP-1 also coactivates the synergistic transactivation of E box-dependent transcription by myogenin and MEF-2C. GST-pulldowns, mammalian two-hybrid analysis, and immunoprecipitation demonstrate that the mechanism involves direct interactions between MEF-2C and GRIP-1 and is associated with the ability of the SRC to interact with the MADS domain of MEF-2C. The HLH region of myogenin mediates the direct interaction of myogenin and GRIP-1. Interestingly, interaction with myogenic factors is mediated by two

  14. Interactions with the Bifunctional Interface of the Transcriptional Coactivator DCoH1 Are Kinetically Regulated

    SciTech Connect

    Wang, Dongli; Coco, Matthew W.; Rose, Robert B.

    2014-12-23

    Pterin-4a-carbinolamine dehydratase (PCD) is a highly conserved enzyme that evolved a second, unrelated function in mammals, as a transcriptional coactivator. As a coactivator, PCD is known as DCoH or dimerization cofactor of the transcription factor HNF-1. These two activities are associated with a change in oligomeric state: from two dimers interacting as an enzyme in the cytoplasm to a dimer interacting with a dimer of HNF-1 in the nucleus. The same interface of DCoH forms both complexes. To determine how DCoH partitions between its two functions, we studied in this paper the folding and stability of the DCoH homotetramer. We show that the DCoH1 homotetramer is kinetically trapped, meaning once it forms it will not dissociate to interact with HNF-1. In contrast, DCoH2, a paralog of DCoH1, unfolds within hours. A simple mutation in the interface of DCoH2 from Ser-51 to Thr, as found in DCoH1, increases the kinetic stability by 9 orders of magnitude, to τ½ ~2 million years. This suggests that the DCoH1·HNF-1 complex must co-fold to interact. We conclude that simple mutations can dramatically affect the dissociation kinetics of a complex. Residue 51 represents a “kinetic hot spot” instead of a “thermodynamic hot spot.” Kinetic regulation allows PCD to adopt two distinct functions. Finally, mutations in DCoH1 associated with diabetes affect both functions of DCoH1, perhaps by disrupting the balance between the two DCoH complexes.

  15. The progesterone receptor coactivator Hic-5 is involved in the pathophysiology of endometriosis.

    PubMed

    Aghajanova, Lusine; Velarde, Michael C; Giudice, Linda C

    2009-08-01

    Endometriosis is an estrogen-dependent disorder primarily associated with pelvic pain and infertility in up to 10% of women of reproductive age. Recent studies suggest that resistance to progesterone action may contribute to the development and pathophysiology of this disorder. In this study we examined the in vivo and in vitro expression and function of one progesterone receptor (PR) coactivator, Hic-5, in human endometrium and endometrial stromal fibroblasts (hESFs) from 29 women with and 30 (control) women without endometriosis. Hic-5 was highly expressed in stromal, but not epithelial, cells in women without endometriosis, in a cycle-dependent manner. In contrast, Hic-5 expression was not regulated during the menstrual cycle in hESFs from women with endometriosis and was significantly reduced in hESFs from women with vs. without disease. Hic-5 mRNA expression throughout the cycle in endometrium from control women, but not those with endometriosis, correlated with expression of PR. Hic-5 mRNA in hESFs was significantly up-regulated in control but not endometriosis hESFs after treatment in vitro with 8-bromoadenosine-cAMP for 96 h but only modestly after 14 d of progesterone treatment. Hic-5 silencing did not influence cAMP-regulated gene expression but affected genes regulated solely by progesterone (e.g. DKK1 and calcitonin). Together the data suggest that the proposed progesterone resistance in endometrium from women with endometriosis derives, in part, from impaired expression of the PR coactivator, Hic-5, in endometrial tissue and cultured endometrial stromal fibroblasts.

  16. Co-activated yet disconnected-Neural correlates of eye closures when trying to stay awake.

    PubMed

    Ong, Ju Lynn; Kong, Danyang; Chia, Tiffany T Y; Tandi, Jesisca; Thomas Yeo, B T; Chee, Michael W L

    2015-09-01

    Spontaneous eye-closures that herald sleep onset become more frequent when we are sleep deprived. Although these are typically associated with decreased responsiveness to external stimuli, it is less clear what occurs in the brain at these transitions to drowsiness and light sleep. To investigate this, task-free fMRI of sleep-deprived participants was acquired. BOLD activity associated with periods of spontaneously occurring eye closures were marked and analyzed. We observed concurrent and extensive hypnagogic co-activation of the extrastriate visual, auditory, and somatosensory cortices as well as the default mode network, consistent with internal sensory activity without external stimulation. Co-activation of fronto-parietal areas known to mediate attentional control could correspond with participants resisting sleep or additional engagement of mental imagery. This constellation of signal changes differed from those elicited by cued eye closures of similar duration and distribution in the same, rested participants. They also differ from signal changes associated with mind-wandering and consolidated light sleep. Concurrent with the observed event-related changes, eye closures elicited additional reduction in functional connectivity within nodes of the DMN and DAN, superposed on already reduced connectivity associated with sleep deprivation. There was concurrent deactivation of the thalamus during eye-closure during the sleep-deprived state but almost similar changes occurred in the well-rested state that may also be relevant. These findings highlight the dynamic shifts in brain activity and connectivity at border between wakefulness and sleep. Copyright © 2015. Published by Elsevier Inc.

  17. Effect of posterior cruciate ligament creep on muscular co-activation around knee: a pilot study.

    PubMed

    Cheng, Xiangrong; Zhang, Tailai; Shan, Xinhai; Wang, Jingyuan

    2014-04-01

    The effect of posterior cruciate ligament (PCL) on muscle co-activation (MCO) is not known though MCO has been extensively studied. The purpose of the study was to investigate the effect of PCL creep on MCO and on joint moment around the knee. Twelve males and twelve females volunteered for this study. PCL creep was estimated via tibial posterior displacement which was elicited by a 20kg dumbbell hanged on horizontal shank near patella for 10min. Electromyography activity from both rectus femoris and biceps femoris as well as muscle strength on the right thigh was recorded synchronically during knee isokinetic flexion-extension performance in speed of 60deg/s as well as 120deg/s on a dynamometer before and after PCL creep. A one-way ANOVA with repeated measures was used to evaluate the effect of creep, gender and speed. The results showed that significant tibial posterior displacement was found (p=0.01) in both male and female groups. No significant increase of joint moment was found in flexion as well as in extension phase in both female and male groups. There was a significant effect of speed (p=0.036) on joint moment in extension phase. Co-activation index (CI) decreased significantly (p=0.049) in extension phase with a significant effect of gender (p⩽0.001). It was concluded that creep developed in PCL due to static posterior load on the proximal tibia could significantly elicit the increase of the activation of agonist muscles but with no compensation from the antagonist in flexion as well as in extension phase. The creep significantly elicited the decrease of the antagonist-agonist CI in extension phase. MCO in females was reduced significantly in extension phase. It was suggested that PCL creep might be one of risk factors to the knee injury in sports activity. Copyright © 2014. Published by Elsevier Ltd.

  18. PIAS1 interacts with FLASH and enhances its co-activation of c-Myb

    PubMed Central

    2011-01-01

    Background FLASH is a huge nuclear protein involved in various cellular functions such as apoptosis signalling, NF-κB activation, S-phase regulation, processing of histone pre-mRNAs, and co-regulation of transcription. Recently, we identified FLASH as a co-activator of the transcription factor c-Myb and found FLASH to be tightly associated with active transcription foci. As a huge multifunctional protein, FLASH is expected to have many interaction partners, some which may shed light on its function as a transcriptional regulator. Results To find additional FLASH-associated proteins, we performed a yeast two-hybrid (Y2H) screening with FLASH as bait and identified the SUMO E3 ligase PIAS1 as an interaction partner. The association appears to involve two distinct interaction surfaces in FLASH. We verified the interaction by Y2H-mating, GST pulldowns, co-IP and ChIP. FLASH and PIAS1 were found to co-localize in nuclear speckles. Functional assays revealed that PIAS1 enhances the intrinsic transcriptional activity of FLASH in a RING finger-dependent manner. Furthermore, PIAS1 also augments the specific activity of c-Myb, and cooperates with FLASH to further co-activate c-Myb. The three proteins, FLASH, PIAS1, and c-Myb, are all co-localized with active RNA polymerase II foci, resembling transcription factories. Conclusions We conclude that PIAS1 is a common partner for two cancer-related nuclear factors, c-Myb and FLASH. Our results point to a functional cooperation between FLASH and PIAS1 in the enhancement of c-Myb activity in active nuclear foci. PMID:21338522

  19. DuOx2 Promoter Regulation by Hormones, Transcriptional Factors and the Coactivator TAZ.

    PubMed

    Cardoso-Weide, L C; Cardoso-Penha, R C; Costa, M W; Ferreira, A C F; Carvalho, D P; Santisteban, P S

    2015-03-01

    The production of H2O2, which is essential to thyroid hormone synthesis, involves two NADPH oxidases: dual oxidases 1 and 2 (DuOx1 and DuOx2). A functional study with human DuOx genes and their 5'-flanking regions showed that DuOx1 and -2 promoters are different from thyroid-specific gene promoters. Furthermore, their transcriptional activities are not restricted to thyroid cells. While regulation of Tg (thyroglobulin) and TPO (thyroperoxidase) expression have been extensively studied, DuOx2 promoter regulation by hormones and transcriptional factors need to be more explored. Herein we investigated the role of TSH, insulin and insulin-like growth factor 1 (IGF-1), as well as the cAMP effect on DuOx2 promoter (ptx41) activity in transfected rat thyroid cell lines (PCCL3). We also assessed DuOx2 promoter activity in the presence of transcriptional factors crucial to thyroid development such as TTF-1 (thyroid transcription factor 1), PAX8, CREB, DREAM, Nkx2.5 and the coactivator TAZ in HeLa and HEK 293T-transfected cells. Our results show that TSH and forskolin, which increase cAMP in thyroid cells, stimulated DuOx2 promoter activity. IGF-1 led to pronounced stimulation, while insulin induction was not statistically different from DuOx2 promoter basal activity. All transcriptional factors selected for this work and coactivator TAZ, except DREAM, stimulated DuOx2 promoter activity. Moreover, Nkx2.5 and TAZ synergistically increased DuOx2 promoter activity. In conclusion, we show that DuOx2 expression is regulated by hormones and transcription factors involved in thyroid organogenesis and carcinogenesis, reinforcing the importance of the control of H2O2 generation in the thyroid.

  20. DuOx2 Promoter Regulation by Hormones, Transcriptional Factors and the Coactivator TAZ

    PubMed Central

    Cardoso-Weide, L.C.; Cardoso-Penha, R.C.; Costa, M.W.; Ferreira, A.C.F.; Carvalho, D.P.; Santisteban, P.S.

    2015-01-01

    The production of H2O2, which is essential to thyroid hormone synthesis, involves two NADPH oxidases: dual oxidases 1 and 2 (DuOx1 and DuOx2). A functional study with human DuOx genes and their 5′-flanking regions showed that DuOx1 and −2 promoters are different from thyroid-specific gene promoters. Furthermore, their transcriptional activities are not restricted to thyroid cells. While regulation of Tg (thyroglobulin) and TPO (thyroperoxidase) expression have been extensively studied, DuOx2 promoter regulation by hormones and transcriptional factors need to be more explored. Herein we investigated the role of TSH, insulin and insulin-like growth factor 1 (IGF-1), as well as the cAMP effect on DuOx2 promoter (ptx41) activity in transfected rat thyroid cell lines (PCCL3). We also assessed DuOx2 promoter activity in the presence of transcriptional factors crucial to thyroid development such as TTF-1 (thyroid transcription factor 1), PAX8, CREB, DREAM, Nkx2.5 and the coactivator TAZ in HeLa and HEK 293T-transfected cells. Our results show that TSH and forskolin, which increase cAMP in thyroid cells, stimulated DuOx2 promoter activity. IGF-1 led to pronounced stimulation, while insulin induction was not statistically different from DuOx2 promoter basal activity. All transcriptional factors selected for this work and coactivator TAZ, except DREAM, stimulated DuOx2 promoter activity. Moreover, Nkx2.5 and TAZ synergistically increased DuOx2 promoter activity. In conclusion, we show that DuOx2 expression is regulated by hormones and transcription factors involved in thyroid organogenesis and carcinogenesis, reinforcing the importance of the control of H2O2 generation in the thyroid. PMID:25960956

  1. Steroid Receptor Coactivator 1 is an Integrator of Glucose and NAD+/NADH Homeostasis

    PubMed Central

    Motamed, Massoud; Rajapakshe, Kimal I.; Hartig, Sean M.; Coarfa, Cristian; Moses, Robb E.; Lonard, David M.

    2014-01-01

    Steroid receptor coactivator 1 (SRC-1) drives diverse gene expression programs necessary for the dynamic regulation of cancer metastasis, inflammation and gluconeogenesis, pointing to its overlapping roles as an oncoprotein and integrator of cell metabolic programs. Nutrient utilization has been intensely studied with regard to cellular adaptation in both cancer and noncancerous cells. Nonproliferating cells consume glucose through the citric acid cycle to generate NADH to fuel ATP generation via mitochondrial oxidative phosphorylation. In contrast, cancer cells undergo metabolic reprogramming to support rapid proliferation. To generate lipids, nucleotides, and proteins necessary for cell division, most tumors switch from oxidative phosphorylation to glycolysis, a phenomenon known as the Warburg Effect. Because SRC-1 is a key coactivator responsible for driving a hepatic gluconeogenic program under fasting conditions, we asked whether SRC-1 responds to alterations in nutrient availability to allow for adaptive metabolism. Here we show SRC-1 is stabilized by the 26S proteasome in the absence of glucose. RNA profiling was used to examine the effects of SRC-1 perturbation on gene expression in the absence or presence of glucose, revealing that SRC-1 affects the expression of complex I of the mitochondrial electron transport chain, a set of enzymes responsible for the conversion of NADH to NAD+. NAD+ and NADH were subsequently identified as metabolites that underlie SRC-1's response to glucose deprivation. Knockdown of SRC-1 in glycolytic cancer cells abrogated their ability to grow in the absence of glucose consistent with SRC-1's role in promoting cellular adaptation to reduced glucose availability. PMID:24438340

  2. Adr1 and Cat8 Mediate Coactivator Recruitment and Chromatin Remodeling at Glucose-Regulated Genes

    PubMed Central

    Biddick, Rhiannon K.; Law, G. Lynn; Young, Elton T.

    2008-01-01

    Background Adr1 and Cat8 co-regulate numerous glucose-repressed genes in S. cerevisiae, presenting a unique opportunity to explore their individual roles in coactivator recruitment, chromatin remodeling, and transcription. Methodology/Principal Findings We determined the individual contributions of Cat8 and Adr1 on the expression of a cohort of glucose-repressed genes and found three broad categories: genes that need both activators for full derepression, genes that rely mostly on Cat8 and genes that require only Adr1. Through combined expression and recruitment data, along with analysis of chromatin remodeling at two of these genes, ADH2 and FBP1, we clarified how these activators achieve this wide range of co-regulation. We find that Adr1 and Cat8 are not intrinsically different in their abilities to recruit coactivators but rather, promoter context appears to dictate which activator is responsible for recruitment to specific genes. These promoter-specific contributions are also apparent in the chromatin remodeling that accompanies derepression: ADH2 requires both Adr1 and Cat8, whereas, at FBP1, significant remodeling occurs with Cat8 alone. Although over-expression of Adr1 can compensate for loss of Cat8 at many genes in terms of both activation and chromatin remodeling, this over-expression cannot complement all of the cat8Δ phenotypes. Conclusions/Significance Thus, at many of the glucose-repressed genes, Cat8 and Adr1 appear to have interchangeable roles and promoter architecture may dictate the roles of these activators. PMID:18197247

  3. Interactions with the Bifunctional Interface of the Transcriptional Coactivator DCoH1 Are Kinetically Regulated

    DOE PAGES

    Wang, Dongli; Coco, Matthew W.; Rose, Robert B.

    2014-12-23

    Pterin-4a-carbinolamine dehydratase (PCD) is a highly conserved enzyme that evolved a second, unrelated function in mammals, as a transcriptional coactivator. As a coactivator, PCD is known as DCoH or dimerization cofactor of the transcription factor HNF-1. These two activities are associated with a change in oligomeric state: from two dimers interacting as an enzyme in the cytoplasm to a dimer interacting with a dimer of HNF-1 in the nucleus. The same interface of DCoH forms both complexes. To determine how DCoH partitions between its two functions, we studied in this paper the folding and stability of the DCoH homotetramer. Wemore » show that the DCoH1 homotetramer is kinetically trapped, meaning once it forms it will not dissociate to interact with HNF-1. In contrast, DCoH2, a paralog of DCoH1, unfolds within hours. A simple mutation in the interface of DCoH2 from Ser-51 to Thr, as found in DCoH1, increases the kinetic stability by 9 orders of magnitude, to τ½ ~2 million years. This suggests that the DCoH1·HNF-1 complex must co-fold to interact. We conclude that simple mutations can dramatically affect the dissociation kinetics of a complex. Residue 51 represents a “kinetic hot spot” instead of a “thermodynamic hot spot.” Kinetic regulation allows PCD to adopt two distinct functions. Finally, mutations in DCoH1 associated with diabetes affect both functions of DCoH1, perhaps by disrupting the balance between the two DCoH complexes.« less

  4. Fatigue-induced adjustment in antagonist coactivation by old adults during a steadiness task.

    PubMed

    Arellano, Christopher J; Caha, David; Hennessey, Joseph E; Amiridis, Ioannis G; Baudry, Stéphane; Enoka, Roger M

    2016-05-01

    The purpose of this study was to determine the adjustments in the level of coactivation during a steadiness task performed by young and old adults after the torque-generating capacity of the antagonist muscles was reduced by a fatiguing contraction. Torque steadiness (coefficient of variation) and electromyographic activity of the extensor and flexor carpi radialis muscles were measured as participants matched a wrist extensor target torque (10% maximum) before and after sustaining an isometric contraction (30% maximum) with wrist flexors to task failure. Time to failure was similar (P = 0.631) for young (417 ± 121 s) and old (452 ± 174 s) adults. The reduction in maximal voluntary contraction torque (%initial) for the wrist flexors after the fatiguing contraction was greater (P = 0.006) for young (32.5 ± 13.7%) than old (21.8 ± 6.6%) adults. Moreover, maximal voluntary contraction torque for the wrist extensors declined for old (-13.7 ± 12.7%; P = 0.030), but not young (-5.4 ± 13.8%; P = 0.167), adults. Torque steadiness during the matching task with the wrist extensors was similar before and after the fatiguing contraction for both groups, but the level of coactivation increased after the fatiguing contraction for old (P = 0.049) but not young (P = 0.137) adults and was twice the amplitude for old adults (P = 0.002). These data reveal that old adults are able to adjust the amount of antagonist muscle activity independent of the agonist muscle during steady submaximal contractions.

  5. Deletion of the metabolic transcriptional coactivator PGC1β induces cardiac arrhythmia

    PubMed Central

    Gurung, Iman S.; Medina-Gomez, Gema; Kis, Adrienn; Baker, Michael; Velagapudi, Vidya; Neogi, Sudeshna Guha; Campbell, Mark; Rodriguez-Cuenca, Sergio; Lelliott, Christopher; McFarlane, Ian; Oresic, Matej; Grace, Andrew A.; Vidal-Puig, Antonio; Huang, Christopher L.-H.

    2011-01-01

    Aims Peroxisome proliferator-activated receptor-γ coactivators PGC1α and PGC1β modulate mitochondrial biogenesis and energy homeostasis. The function of these transcriptional coactivators is impaired in obesity, insulin resistance, and type 2 diabetes. We searched for transcriptomic, lipidomic, and electrophysiological alterations in PGC1β−/− hearts potentially associated with increased arrhythmic risk in metabolic diseases. Methods and results Microarray analysis in mouse PGC1β−/− hearts confirmed down-regulation of genes related to oxidative phosphorylation and the electron transport chain and up-regulation of hypertrophy- and hypoxia-related genes. Lipidomic analysis showed increased levels of the pro-arrhythmic and pro-inflammatory lipid, lysophosphatidylcholine. PGC1β−/− mouse electrocardiograms showed irregular heartbeats and an increased incidence of polymorphic ventricular tachycardia following isoprenaline infusion. Langendorff-perfused PGC1β−/− hearts showed action potential alternans, early after-depolarizations, and ventricular tachycardia. PGC1β−/− ventricular myocytes showed oscillatory resting potentials, action potentials with early and delayed after-depolarizations, and burst firing during sustained current injection. They showed abnormal diastolic Ca2+ transients, whose amplitude and frequency were increased by isoprenaline, and Ca2+ currents with negatively shifted inactivation characteristics, with increased window currents despite unaltered levels of CACNA1C RNA transcripts. Inwardly and outward rectifying K+ currents were all increased. Quantitiative RT-PCR demonstrated increased SCN5A, KCNA5, RYR2, and Ca2+-calmodulin dependent protein kinase II expression. Conclusion PGC1β−/− hearts showed a lysophospholipid-induced cardiac lipotoxicity and impaired bioenergetics accompanied by an ion channel remodelling and altered Ca2+ homeostasis, converging to produce a ventricular arrhythmic phenotype particularly during

  6. Identification of polyproline II regions derived from the proline-rich nuclear receptor coactivators PNRC and PNRC2: new insights for ERα coactivator interactions.

    PubMed

    Byrne, C; Miclet, E; Broutin, I; Gallo, D; Pelekanou, V; Kampa, M; Castanas, E; Leclercq, G; Jacquot, Y

    2013-10-01

    Protein-protein interactions are crucial for signal transductions required for cell differentiation and proliferation. Their modulation is therefore key to the development of therapeutic alternatives, particularly in the context of cancer. According to literature data, the polyproline-rich nuclear receptor coactivators PNRC and PNRC2 interact with estrogen receptor (ERα) through their PxxP SH3-binding motifs. In a search to identify the molecular features governing this interaction, we explored using electronic circular dichroism (ECD) spectroscopy and molecular dynamics (MD) calculations, the capacity of a range of putative biologically active peptides derived from these proteins and containing this PxxP motif(s) to form polyproline II (PPII) domains. An additional more exhaustive structural study on a lead PPII peptide was also performed using 2D nuclear magnetic resonance (NMR) spectroscopy. With the exception of one of all the investigated peptides (PNRC-D), binding assays failed to detect any affinity for Grb2 SH3 domains, suggesting that PPII motifs issued from Grb2 antagonists have a binding mode distinct from those derived from Grb2 agonists. Instead, the peptides revealed a competitive binding ability against a synthetic peptide (ERα17p) with a putative PPII-cognate domain located within a coregulator recruitment region of ERα (AF-2 site). Our work, which constitutes the first structure-related interaction study concerning PNRC and PNRC2, supports not only the existence of PxxP-induced PPII sequences in these coregulators, but also confirms the presence of a PPII recognition site in the AF-2 of the steroid receptor ERα, a region important for transcription regulation. © 2013 Wiley Periodicals, Inc.

  7. Mediator subunit MED1 is a T3-dependent and T3-independent coactivator on the thyrotropin β gene promoter

    SciTech Connect

    Matsui, Keiji; Oda, Kasumi; Mizuta, Shumpei; Ishino, Ruri; Urahama, Norinaga; Hasegawa, Natsumi; Roeder, Robert G.; Ito, Mitsuhiro

    2013-10-11

    Highlights: •MED1 is a bona fide T3-dependent coactivator on TSHB promoter. •Mice with LxxLL-mutant MED1 have attenuated TSHβ mRNA and thyroid hormone levels. •MED1 activates TSHB promoter T3-dependently in cultured cells. •T3-dependent MED1 action is enhanced when SRC1/SRC2 or HDAC2 is downregulated. •MED1 is also a T3-independent GATA2/Pit1 coactivator on TSHB promoter. -- Abstract: The MED1 subunit of the Mediator transcriptional coregulator complex is a nuclear receptor-specific coactivator. A negative feedback mechanism of thyroid-stimulating hormone (TSH, or thyrotropin) expression in the thyrotroph in the presence of triiodothyronine (T3) is employed by liganded thyroid hormone receptor β (TRβ) on the TSHβ gene promoter, where conventional histone-modifying coactivators act as corepressors. We now provide evidence that MED1 is a ligand-dependent positive cofactor on this promoter. TSHβ gene transcription was attenuated in MED1 mutant mice in which the nuclear receptor-binding ability of MED1 was specifically disrupted. MED1 stimulated GATA2- and Pit1-mediated TSHβ gene promoter activity in a ligand-independent manner in cultured cells. MED1 also stimulated transcription from the TSHβ gene promoter in a T3-dependent manner. The transcription was further enhanced when the T3-dependent corepressors SRC1, SRC2, and HDAC2 were downregulated. Hence, MED1 is a T3-dependent and -independent coactivator on the TSHβ gene promoter.

  8. Coactivation of the PI3K/Akt and ERK signaling pathways in PCB153-induced NF-κB activation and caspase inhibition

    SciTech Connect

    Liu, Changjiang; Yang, Jixin; Fu, Wenjuan; Qi, Suqin; Wang, Chenmin; Quan, Chao; Yang, Kedi

    2014-06-15

    Polychlorinated biphenyls (PCBs) are a group of persistent and widely distributed environmental pollutants that have various deleterious effects, e.g., neurotoxicity, endocrine disruption and reproductive abnormalities. In order to verify the hypothesis that the PI3K/Akt and MAPK pathways play important roles in hepatotoxicity induced by PCBs, Sprague–Dawley (SD) rats were dosed with PCB153 intraperitoneally at 0, 4, 16 and 32 mg/kg for five consecutive days; BRL cells (rat liver cell line) were treated with PCB153 (0, 1, 5, and 10 μM) for 24 h. Results indicated that the PI3K/Akt and ERK pathways were activated in vivo and in vitro after exposure to PCB153, and protein levels of phospho-Akt and phospho-ERK were significantly increased. Nuclear factor-κB (NF-κB) activation and caspase-3, -8 and -9 inhibition caused by PCB153 were also observed. Inhibiting the ERK pathway significantly attenuated PCB153-induced NF-κB activation, whereas inhibiting the PI3K/Akt pathway hardly influenced phospho-NF-κB level. However, inhibiting the PI3K/Akt pathway significantly elevated caspase-3, -8 and -9 activities, while the ERK pathway only synergistically regulated caspase-9. Proliferating cell nuclear antigen (PCNA), a reliable indicator of cell proliferation, was also induced. Moreover, PCB153 led to hepatocellular hypertrophy and elevated liver weight. Taken together, PCB153 leads to aberrant proliferation and apoptosis of hepatocytes through NF-κB activation and caspase inhibition, and coactivated PI3K/Akt and ERK pathways play critical roles in PCB153-induced hepatotoxicity. - Highlights: • PCB153 led to hepatotoxicity through NF-κB activation and caspase inhibition. • The PI3K/Akt and ERK pathways were coactivated in vivo and in vitro by PCB153. • The ERK pathway regulated levels of phospho-NF-κB and caspase-9. • The PI3K/Akt pathway regulated levels of caspase-3, -8 and -9.

  9. Growing Up with Play

    ERIC Educational Resources Information Center

    Katch, Jane

    2008-01-01

    Many adults are afraid of boys' play today, believing that the aggression that is so common in boys' fantasies is dangerous and might make them become violent men. This personal reflection describes the importance of multiage play in showing little boys how to become big boys while encouraging empathy and emotional growth in older boys. The author…

  10. Play and Digital Media

    ERIC Educational Resources Information Center

    Johnson, James E.; Christie, James F.

    2009-01-01

    This article examines how play is affected by computers and digital toys. Research indicates that when computer software targeted at children is problem-solving oriented and open-ended, children tend to engage in creative play and interact with peers in a positive manner. On the other hand, drill-and-practice programs can be quite boring and limit…

  11. Return to Play

    ERIC Educational Resources Information Center

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  12. Play as Experience

    ERIC Educational Resources Information Center

    Henricks, Thomas S.

    2015-01-01

    The author investigates what he believes one of the more important aspects of play--the experience it generates in its participants. He considers the quality of this experience in relation to five ways of viewing play--as action, interaction, activity, disposition, and within a context. He treats broadly the different forms of affect, including…

  13. Let's Just Play

    ERIC Educational Resources Information Center

    Schmidt, Janet

    2003-01-01

    Children have a right to play. The idea is so simple it seems self-evident. But a stroll through any toy superstore, or any half-hour of so-called "children's" programming on commercial TV, makes it clear that violence, not play, dominates what's being sold. In this article, the author discusses how teachers and parents share the responsibility in…

  14. Clinical Intuition at Play

    ERIC Educational Resources Information Center

    Marks-Tarlow, Terry

    2014-01-01

    A clinical psychologist and consulting psychotherapist discusses how elements of play, inherent in the intuition required in analysis, can provide a cornerstone for serious therapeutic work. She argues that many aspects of play--its key roles in human development, individual growth, and personal creativity, among others--can help therapists and…

  15. The Play's the Thing

    ERIC Educational Resources Information Center

    Bateman, Barbara

    2005-01-01

    The modern special education theater in the United States has hosted many plays, none with a larger or more diverse cast than the learning disabilities (LD) play. During the prologue, the children with LD were waiting in the wings, not yet identified as LD but there, nonetheless. With the advent of compulsory education in this country, awareness…

  16. Let's Just Play

    ERIC Educational Resources Information Center

    Schmidt, Janet

    2003-01-01

    Children have a right to play. The idea is so simple it seems self-evident. But a stroll through any toy superstore, or any half-hour of so-called "children's" programming on commercial TV, makes it clear that violence, not play, dominates what's being sold. In this article, the author discusses how teachers and parents share the responsibility in…

  17. Role Playing and Skits

    ERIC Educational Resources Information Center

    Letwin, Robert, Ed.

    1975-01-01

    Explores non-scripted role playing, dialogue role playing, sociodrama, and skits as variations of simulation techniques. Provides step-by-step guidelines for conducting such sessions. Successful Meetings, Bill Communications, Inc., 1422 Chestnut Street, Philadelphia, Pa. 19102. Subscription Rates: yearly (US, Canada, Mexico) $14.00; elsewhere,…

  18. Role Playing and Skits

    ERIC Educational Resources Information Center

    Letwin, Robert, Ed.

    1975-01-01

    Explores non-scripted role playing, dialogue role playing, sociodrama, and skits as variations of simulation techniques. Provides step-by-step guidelines for conducting such sessions. Successful Meetings, Bill Communications, Inc., 1422 Chestnut Street, Philadelphia, Pa. 19102. Subscription Rates: yearly (US, Canada, Mexico) $14.00; elsewhere,…

  19. Is Play Serious?

    ERIC Educational Resources Information Center

    Darling, John

    1983-01-01

    The importance of play (1) to players--players' values, attitudes, and mental states, and whether or not players take their playing seriously; (2) in child development as argued by Rousseau, Froebel, and Neill; and (3) as serious or nonserious business as argued by Johan Huizinga and R. F. Dearden is examined. (SR)

  20. Return to Play

    ERIC Educational Resources Information Center

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  1. Play, Epideictic and Argument.

    ERIC Educational Resources Information Center

    Hoffman, David C.

    This paper explores the relationship between epideictic and argument, noting that the relationship is a "troublesome" one. The first part moves toward new definitions of epideictic and argument (taking the view that epideictic rises out of human play) and locates argument on the boundary where the play-world meets the "real" or…

  2. The Fear of Play

    ERIC Educational Resources Information Center

    Almon, Joan

    2009-01-01

    Real play--play that is initiated and directed by children and that bubbles up from within the child rather than being imposed by adults--has largely disappeared from the landscape of childhood in the United States. There are many reasons for this, such as the long hours spent in front of screens each day or in activities organized by adults. In…

  3. The Fear of Play

    ERIC Educational Resources Information Center

    Almon, Joan

    2009-01-01

    Real play--play that is initiated and directed by children and that bubbles up from within the child rather than being imposed by adults--has largely disappeared from the landscape of childhood in the United States. There are many reasons for this, such as the long hours spent in front of screens each day or in activities organized by adults. In…

  4. Play, Policy & Practice.

    ERIC Educational Resources Information Center

    Klugman, Edgar, Ed.

    In 1992, the U.S.-Israel Binational Science Foundation (BSF), in conjunction with Wheelock College (Boston), sponsored its second workshop on children's play, entitled "Play and Cognitive Ability: The Cultural Context." This volume reflects the presentations and discussions held at the workshop, offering perspectives on children's play…

  5. Play, Policy & Practice.

    ERIC Educational Resources Information Center

    Klugman, Edgar, Ed.

    In 1992, the U.S.-Israel Binational Science Foundation (BSF), in conjunction with Wheelock College (Boston), sponsored its second workshop on children's play, entitled "Play and Cognitive Ability: The Cultural Context." This volume reflects the presentations and discussions held at the workshop, offering perspectives on children's play…

  6. Theories of Play.

    ERIC Educational Resources Information Center

    Peller, Lili E.

    1996-01-01

    Discusses several theories of play advanced before the development of psychoanalysis, including the theories of surplus energy, recreation, and practice. Examines the psychoanalytical view advanced by Freud and others, which focuses on the emotional release of play and its role in discovery and learning. (MDM)

  7. Play, Toys and Television.

    ERIC Educational Resources Information Center

    Brougere, Gilles

    In Western societies, television has transformed the life, culture, and points of reference of the child. Its particular sphere of influence is the child's play culture. This play culture is not hermetic: it is very oriented toward manipulation; has a symbolic role as a representational medium; evolves along with the child; has a certain amount of…

  8. An Invitation to Play.

    ERIC Educational Resources Information Center

    Lange, Jenny; Zieher, Connie

    The manual is intended to provide suggestions for play to parents of young children with exceptional educational needs. Nineteen types of activities are described and pictured, including make believe with boxes, dress-up activities, kitchen play, bubbles, small motor activities using beans and buttons, use of throw-away materials, painting,…

  9. Play, experimentation and creativity.

    PubMed

    Caper, R

    1996-10-01

    Beginning with Klein's description of a psychotic boy's inability to play, published in 1930, the author explores the relationship between play and symbol-formation, and the use of play by children and adults as a serious type of experimentation by means of which one learns about the internal and external worlds. In this view, play is a way of externalising fantasies originating in one's inner world so they may be seen and learned about. Play is also a vehicle of projection, a fact that allows one to use it to assess the impact of one's inner world on the external world, especially on the minds of one's objects. In this way, playing becomes a way of probing external reality as well. This type of learning depends on the ability to keep internal and external realities distinct even while projecting the former into the latter. In psychotic states, this ability is lost, and the psychotic patient's projections, instead of being usable as a form of playful experimentation, lead to delusions and claustrophobic anxiety. A brief clinical vignette is presented to illustrate these points. The author then explores the application of these ideas to an understanding of artistic creativity, and makes some observations about possible underlying unities between play, scientific experimentation and artistic creativity.

  10. A Role for Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α in Nucleus Accumbens Neuron Subtypes in Cocaine Action.

    PubMed

    Chandra, Ramesh; Engeln, Michel; Francis, T Chase; Konkalmatt, Prasad; Patel, Dipal; Lobo, Mary Kay

    2017-04-01

    Molecules critically involved in cocaine behavioral plasticity are known to regulate and interact with peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α). In addition, the PGC-1α promoter has binding sites for early growth response 3 (Egr3), which plays a dynamic role in cocaine action in nucleus accumbens (NAc) medium spiny neuron (MSN) subtypes, those enriched in dopamine receptor D1 (D1-MSN) versus D2 (D2-MSN). However, the role of PGC-1α in NAc in cocaine action is unknown. PGC-1α messenger RNA and protein were examined in NAc after repeated cocaine exposure. Binding of Egr3 to and histone methylation at the PGC-1α promoter was examined in NAc using chromatin immunoprecipitation after repeated cocaine. PGC-1α ribosome-associated messenger RNA in MSN subtypes was assessed after repeated cocaine using D1-Cre-RiboTag and D2-Cre-RiboTag lines. Finally, PGC-1α was expressed in NAc D1-MSNs versus D2-MSNs using a Cre-inducible adeno-associated virus and Cre lines during cocaine conditioned place preference and cocaine-induced locomotion. Repeated cocaine increased PGC-1α levels and increased Egr3 binding and H3K4me3 at the PGC-1α promoter in NAc. Increased PGC-1α occurred in D1-MSNs, while D2-MSNs showed reduced levels. Viral-mediated expression of PGC-1α in D1-MSNs enhanced behavioral responses to cocaine, while expression in D2-MSNs blunted these behaviors. We demonstrate a novel role for PGC-1α in NAc in cocaine action. PGC-1α is enhanced in NAc D1-MSNs, specifically after cocaine exposure. These data are consistent with increased active methylation and Egr3 binding at the PGC-1α promoter. Finally, we demonstrate a bidirectional role for PGC-1α in mediating behavioral plasticity to cocaine through D1-MSNs versus D2-MSNs. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  11. The Scottish Play.

    ERIC Educational Resources Information Center

    Wheat, Chris

    1999-01-01

    Recounts an episode when, as young schoolboys, Prince Charles and classmates presented "Macbeth" as an end-of-term-play. Traces the events at school that took on different meanings when viewed from maturity. (NH)

  12. Taiman acts as a coactivator of Yorkie in the Hippo pathway to promote tissue growth and intestinal regeneration

    PubMed Central

    Wang, Chao; Yin, Meng-Xin; Wu, Wei; Dong, Liang; Wang, Shimin; Lu, Yi; Xu, Jinjin; Wu, Wenqing; Li, Sheng; Zhao, Yun; Zhang, Lei

    2016-01-01

    The Hippo signaling pathway regulates tissue growth and organ size through controlling cell growth, proliferation and apoptosis. During these processes, the coactivator Yorkie partners with the transcription factor Scalloped to mediate Hippo pathway-regulated cellular functions. Here, we demonstrate that Taiman facilitates the activity of Yorkie. First, Taiman overexpression upregulates Hippo pathway-responsive genes and induces tissue overgrowth. Second, the loss of tai downregulates the expression of Hippo pathway target genes and reduces organ size as well as tissue overgrowth caused by Yorkie overexpression. Furthermore, we provide evidence that Taiman binds to Yorkie and facilitates the activity of Yorkie-Scalloped to activate the transcription of several Hippo pathway target genes. Moreover, we found that the C-terminus of Taiman is indispensable for the function of Taiman in Hippo signaling. Finally, we demonstrate that Taiman is also required in intestinal stem cell proliferation. Our findings suggest Taiman is an essential coactivator of Yorkie. PMID:27462453

  13. Multifunctional human transcriptional coactivator protein PC4 is a substrate of Aurora kinases and activates the Aurora enzymes.

    PubMed

    Dhanasekaran, Karthigeyan; Kumari, Sujata; Boopathi, Ramachandran; Shima, Hiroki; Swaminathan, Amrutha; Bachu, Mahesh; Ranga, Udaykumar; Igarashi, Kazuhiko; Kundu, Tapas K

    2016-03-01

    Positive coactivator 4 (PC4), a human transcriptional coactivator, is involved in diverse processes like chromatin organization and transcription regulation. It is hyperphosphorylated during mitosis, with unknown significance. For the first time, we demonstrate the function of PC4 outside the nucleus upon nuclear envelope breakdown. A fraction of PC4 associates with Aurora A and Aurora B and undergoes phosphorylation, following which PC4 activates both Aurora A and B to sustain optimal kinase activity to maintain the phosphorylation gradient for the proper functioning of the mitotic machinery. This mitotic role is evident in PC4 knockdown cells where the defects are rescued only by the catalytically active Aurora kinases, but not the kinase-dead mutants. Similarly, the PC4 phosphodeficient mutant failed to rescue such defects. Hence, our observations establish a novel mitotic function of PC4 that might be dependent on Aurora kinase-mediated phosphorylation.

  14. Bifurcation analysis and potential landscapes of the p53-Mdm2 module regulated by the co-activator programmed cell death 5.

    PubMed

    Bi, Yuanhong; Yang, Zhuoqin; Zhuge, Changjing; Lei, Jinzhi

    2015-11-01

    The dynamics of p53 play important roles in the regulation of cell fate decisions in response to various stresses, and programmed cell death 5 (PDCD5) functions as a co-activator of p53 that modulates p53 dynamics. In the present paper, we investigated how p53 dynamics are modulated by PDCD5 during the deoxyribose nucleic acid damage response using methods of bifurcation analysis and potential landscape. Our results revealed that p53 activities display rich dynamics under different PDCD5 levels, including monostability, bistability with two stable steady states, oscillations, and the coexistence of a stable steady state (or two states) and an oscillatory state. The physical properties of the p53 oscillations were further demonstrated by the potential landscape in which the potential force attracts the system state to the limit cycle attractor, and the curl flux force drives coherent oscillation along the cyclic trajectory. We also investigated the efficiency with which PDCD5 induced p53 oscillations. We show that Hopf bifurcation can be induced by increasing the PDCD5 efficiency and that the system dynamics exhibited clear transition features in both barrier height and energy dissipation when the efficiency was close to the bifurcation point.

  15. Bifurcation analysis and potential landscapes of the p53-Mdm2 module regulated by the co-activator programmed cell death 5

    NASA Astrophysics Data System (ADS)

    Bi, Yuanhong; Yang, Zhuoqin; Zhuge, Changjing; Lei, Jinzhi

    2015-11-01

    The dynamics of p53 play important roles in the regulation of cell fate decisions in response to various stresses, and programmed cell death 5 (PDCD5) functions as a co-activator of p53 that modulates p53 dynamics. In the present paper, we investigated how p53 dynamics are modulated by PDCD5 during the deoxyribose nucleic acid damage response using methods of bifurcation analysis and potential landscape. Our results revealed that p53 activities display rich dynamics under different PDCD5 levels, including monostability, bistability with two stable steady states, oscillations, and the coexistence of a stable steady state (or two states) and an oscillatory state. The physical properties of the p53 oscillations were further demonstrated by the potential landscape in which the potential force attracts the system state to the limit cycle attractor, and the curl flux force drives coherent oscillation along the cyclic trajectory. We also investigated the efficiency with which PDCD5 induced p53 oscillations. We show that Hopf bifurcation can be induced by increasing the PDCD5 efficiency and that the system dynamics exhibited clear transition features in both barrier height and energy dissipation when the efficiency was close to the bifurcation point.

  16. Correspondent Functional Topography of the Human Left Inferior Parietal Lobule at Rest and Under Task Revealed Using Resting-State fMRI and Coactivation Based Parcellation.

    PubMed

    Wang, Jiaojian; Xie, Sangma; Guo, Xin; Becker, Benjamin; Fox, Peter T; Eickhoff, Simon B; Jiang, Tianzi

    2017-03-01

    The human left inferior parietal lobule (LIPL) plays a pivotal role in many cognitive functions and is an important node in the default mode network (DMN). Although many previous studies have proposed different parcellation schemes for the LIPL, the detailed functional organization of the LIPL and the exact correspondence between the DMN and LIPL subregions remain unclear. Mounting evidence indicates that spontaneous fluctuations in the brain are strongly associated with cognitive performance at the behavioral level. However, whether a consistent functional topographic organization of the LIPL during rest and under task can be revealed remains unknown. Here, they used resting-state functional connectivity (RSFC) and task-related coactivation patterns separately to parcellate the LIPL and identified seven subregions. Four subregions were located in the supramarginal gyrus (SMG) and three subregions were located in the angular gyrus (AG). The subregion-specific networks and functional characterization revealed that the four anterior subregions were found to be primarily involved in sensorimotor processing, movement imagination and inhibitory control, audition perception and speech processing, and social cognition, whereas the three posterior subregions were mainly involved in episodic memory, semantic processing, and spatial cognition. The results revealed a detailed functional organization of the LIPL and suggested that the LIPL is a functionally heterogeneous area. In addition, the present study demonstrated that the functional architecture of the LIPL during rest corresponds with that found in task processing. Hum Brain Mapp 38:1659-1675, 2017. © 2017 Wiley Periodicals, Inc.

  17. The High Mobility Group Protein 1 Is a Coactivator of Herpes Simplex Virus ICP4 In Vitro

    PubMed Central

    Carrozza, Michael J.; DeLuca, Neal

    1998-01-01

    ICP4 is an activator of herpes simplex virus early and late gene transcription during infection and in vitro can efficiently activate the transcription of a core promoter template containing only a TATA box and an initiator element. In this study, we noted that the extent of activation by ICP4 in vitro was highly dependent on the purity of TFIID when recombinant TFIIB, TFIIE, and TFIIF were used as sources of these factors. ICP4 efficiently activated transcription with a crude TFIID fraction. However, when immunoaffinity-purified TFIID was used in place of the less pure TFIID, ICP4 activated transcription to a significantly lesser extent. This finding indicated that the crude TFIID fraction may contain additional factors that serve as coactivators of ICP4. To test this hypothesis, the crude TFIID preparation was further fractionated by gel filtration chromatography. The TFIID that eluted from the column lacked the hypothesized coactivator activity. A fraction well separated from TFIID contained an activity that when added with the TFIID fraction resulted in higher levels of transcription in the presence ICP4. Further purification of the coactivator-containing fraction resulted in the isolation of a single 30-kDa polypeptide (p30). p30 was also shown to serve as a coactivator of ICP4 with immunoaffinity-purified TFIID; however, p30 had no effect on basal transcription. Amino acid sequence analysis revealed that p30 was the high mobility group protein 1, which has been shown to facilitate the formation of higher-order DNA-protein complexes. PMID:9658123

  18. Modeling violations of the race model inequality in bimodal paradigms: co-activation from decision and non-decision components.

    PubMed

    Zehetleitner, Michael; Ratko-Dehnert, Emil; Müller, Hermann J

    2015-01-01

    The redundant-signals paradigm (RSP) is designed to investigate response behavior in perceptual tasks in which response-relevant targets are defined by either one or two features, or modalities. The common finding is that responses are speeded for redundantly compared to singly defined targets. This redundant-signals effect (RSE) can be accounted for by race models if the response times do not violate the race model inequality (RMI). When there are violations of the RMI, race models are effectively excluded as a viable account of the RSE. The common alternative is provided by co-activation accounts, which assume that redundant target signals are integrated at some processing stage. However, "co-activation" has mostly been only indirectly inferred and the accounts have only rarely been explicitly modeled; if they were modeled, the RSE has typically been assumed to have a decisional locus. Yet, there are also indications in the literature that the RSE might originate, at least in part, at a non-decisional or motor stage. In the present study, using a distribution analysis of sequential-sampling models (ex-Wald and Ratcliff Diffusion model), the locus of the RSE was investigated for two bimodal (audio-visual) detection tasks that strongly violated the RMI, indicative of substantial co-activation. Three model variants assuming different loci of the RSE were fitted to the quantile reaction time proportions: a decision, a non-decision, and a combined variant both to vincentized group as well as individual data. The results suggest that for the two bimodal detection tasks, co-activation has a shared decisional and non-decisional locus. These findings point to the possibility that the mechanisms underlying the RSE depend on the specifics (task, stimulus, conditions, etc.) of the experimental paradigm.

  19. Yeast transcription co-activator Sub1 and its human homolog PC4 preferentially bind to G-quadruplex DNA

    PubMed Central

    Gao, Jun; Zybailov, Boris L.; Byrd, Alicia K.; Griffin, Wezley C.; Chib, Shubeena; Mackintosh, Samuel G.; Tackett, Alan J.; Raney, Kevin D.

    2015-01-01

    Using a G-quadruplex bait, we identified the transcription co-activator Sub1 as a G-quadruplex binding protein by quantitative LC-MS/MS and demonstrated in vivo G-quadruplex binding by ChIP. In vitro, Sub1, and its human homolog PC4, bind preferentially to G-quadruplexes. This provides a possible mechanism by which G-quadruplexes can influence gene transcription. PMID:25813861

  20. Can Co-Activation of Nrf2 and Neurotrophic Signaling Pathway Slow Alzheimer’s Disease?

    PubMed Central

    Murphy, Kelsey E.; Park, Joshua J.

    2017-01-01

    Alzheimer’s disease (AD) is a multifaceted disease that is hard to treat by single-modal treatment. AD starts with amyloid peptides, mitochondrial dysfunction, and oxidative stress and later is accompanied with chronic endoplasmic reticulum (ER) stress and autophagy dysfunction, resulting in more complicated pathogenesis. Currently, few treatments can modify the complicated pathogenic progress of AD. Compared to the treatment with exogenous antioxidants, the activation of global antioxidant defense system via Nrf2 looks more promising in attenuating oxidative stress in AD brains. Accompanying the activation of the Nrf2-mediated antioxidant defense system that reduce the AD-causative factor, oxidative stress, it is also necessary to activate the neurotrophic signaling pathway that replaces damaged organelles and molecules with new ones. Thus, the dual actions to activate both the Nrf2 antioxidant system and neurotrophic signaling pathway are expected to provide a better strategy to modify AD pathogenesis. Here, we review the current understanding of AD pathogenesis and neuronal defense systems and discuss a possible way to co-activate the Nrf2 antioxidant system and neurotrophic signaling pathway with the hope of helping to find a better strategy to slow AD. PMID:28561773

  1. Structural basis of coactivation of liver receptor homolog-1 by β-catenin

    PubMed Central

    Yumoto, Fumiaki; Nguyen, Phuong; Sablin, Elena P.; Baxter, John D.; Webb, Paul; Fletterick, Robert J.

    2012-01-01

    We report the three-dimensional structure of a β-catenin armadillo repeat in complex with the liver receptor homolog-1 (LRH-1) ligand binding domain at 2.8 Å resolution as the first structure of β-catenin in complex with any nuclear receptor. The surface of β-catenin that binds LRH-1 partly overlaps defined contact sites for peptide segments of β-catenin partners, including T-cell factor-4. The surface of LRH-1 that engages β-catenin is comprised of helices 1, 9, and 10 and is distinct from known interaction surfaces of LRH-1, including corepressor and coactivator binding sites. Targeted mutagenesis of amino acids forming both sides of the LRH-1/β-catenin interface reveals that they are essential for stable interactions between these proteins in solution. The LRH-1 binding site in β-catenin is also required for association with androgen receptor, providing evidence that the observed LRH-1/β-catenin interaction may be prototypic. PMID:22187462

  2. Coactivator MED1 ablation in keratinocytes results in hair-cycling defects and epidermal alterations.

    PubMed

    Oda, Yuko; Hu, Lizhi; Bul, Vadim; Elalieh, Hashem; Reddy, Janardan K; Bikle, Daniel D

    2012-04-01

    The transcriptional coactivator complex Mediator (MED) facilitates transcription of nuclear hormone receptors and other transcription factors. We have previously isolated the MED complex from primary keratinocytes (KCs) as the vitamin D receptor-interacting protein complex. We identified a role for MED in KC proliferation and differentiation in cultured KCs. Here, we investigated the in vivo role of MED by generating a conditional null mice model in which a critical subunit of the MED complex, MED1, is deleted from their KCs. The MED1 ablation resulted in aberrant hair differentiation and cycling, leading to hair loss. During the first hair follicle (HF) cycle, MED1 deletion resulted in a rapid regression of the HFs. Hair differentiation was reduced, and β-catenin/vitamin D receptor (VDR)-regulated gene expression was markedly decreased. In the subsequent adult hair cycle, MED1 ablation activated the initiation of HF cycling. Shh signaling was increased, but terminal differentiation was not sufficient. Deletion of MED1 also caused hyperproliferation of interfollicular epidermal KCs, and increased the expression of epidermal differentiation markers. These results indicate that MED1 has a critical role in regulating hair/epidermal proliferation and differentiation.

  3. Prediction of missing flow records using multilayer perceptron and coactive neurofuzzy inference system.

    PubMed

    Tfwala, Samkele S; Wang, Yu-Min; Lin, Yu-Chieh

    2013-01-01

    Hydrological data are often missing due to natural disasters, improper operation, limited equipment life, and other factors, which limit hydrological analysis. Therefore, missing data recovery is an essential process in hydrology. This paper investigates the accuracy of artificial neural networks (ANN) in estimating missing flow records. The purpose is to develop and apply neural networks models to estimate missing flow records in a station when data from adjacent stations is available. Multilayer perceptron neural networks model (MLP) and coactive neurofuzzy inference system model (CANFISM) are used to estimate daily flow records for Li-Lin station using daily flow data for the period 1997 to 2009 from three adjacent stations (Nan-Feng, Lao-Nung and San-Lin) in southern Taiwan. The performance of MLP is slightly better than CANFISM, having R (2) of 0.98 and 0.97, respectively. We conclude that accurate estimations of missing flow records under the complex hydrological conditions of Taiwan could be attained by intelligent methods such as MLP and CANFISM.

  4. Simple arithmetic development in school age: The coactivation and selection of arithmetic facts.

    PubMed

    Megías, Patricia; Macizo, Pedro

    2015-10-01

    We evaluated the possible inhibitory mechanism responsible for selecting arithmetic facts in children from 8 or 9 years to 12 or 13 years of age. To this end, we used an adapted version of the negative priming paradigm (NP paradigm) in which children received additions and they decided whether they were correct or not. When an addition was incorrect but the result was that of multiplying the operands (e.g., 2 + 4 = 8), only children from 10 or 11 years of age onward took more time to respond compared with control additions with unrelated results, suggesting that they coactivated arithmetic knowledge of multiplications even when it was irrelevant to perform the task. Furthermore, children from 10 or 11 years of age onward were slower to respond when the result of multiplying the operands was presented again in a correct addition problem (e.g., 2 + 6 = 8). This result showed the development of an inhibitory mechanism involved in the selection of arithmetic facts through formal education. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Simple arithmetic: electrophysiological evidence of coactivation and selection of arithmetic facts.

    PubMed

    Megías, Patricia; Macizo, Pedro

    2016-11-01

    This study aimed at exploring the time course of processes underlying the associative confusion effect. We also evaluated the consequences of selecting arithmetic facts to resolve addition problems. We gathered electrophysiological evidence when participants performed a verification task. Simple addition problems were presented in blocks of two trials and participants decided whether they were correct or not. The N400-like component was considered an index of semantic access (i.e., the retrieval of arithmetic facts), and the P200 component was used to determine the difficulty associated with encoding after the answer to an addition problem. When an addition problem was incorrect but the result presented to the participant was that of multiplying the operands (e.g., 2 + 4 = 8), N400-like amplitude was reduced relative to an unrelated condition (e.g., 2 + 4 = 10). This finding suggested that the coactivation of addition and multiplication facts took place. Furthermore, the P200 amplitude was more positive when participants answered to addition problems whose result was that of multiplying the operands of the previous trial (e.g., 2 + 6 = 8). This suggests that irrelevant results were inhibited and it was difficult to encode them later.

  6. Mitochondrial Fusion Is Increased by the Nuclear Coactivator PGC-1β

    PubMed Central

    Liesa, Marc; Borda-d'Água, Bárbara; Medina-Gómez, Gema; Lelliott, Christopher J.; Paz, José Carlos; Rojo, Manuel; Palacín, Manuel; Vidal-Puig, Antonio; Zorzano, Antonio

    2008-01-01

    Background There is no evidence to date on whether transcriptional regulators are able to shift the balance between mitochondrial fusion and fission events through selective control of gene expression. Methodology/Principal Findings Here, we demonstrate that reduced mitochondrial size observed in knock-out mice for the transcriptional regulator PGC-1β is associated with a selective reduction in Mitofusin 2 (Mfn2) expression, a mitochondrial fusion protein. This decrease in Mfn2 is specific since expression of the remaining components of mitochondrial fusion and fission machinery were not affected. Furthermore, PGC-1β increases mitochondrial fusion and elongates mitochondrial tubules. This PGC-1β-induced elongation specifically requires Mfn2 as this process is absent in Mfn2-ablated cells. Finally, we show that PGC-1β increases Mfn2 promoter activity and transcription by coactivating the nuclear receptor Estrogen Related Receptor α (ERRα). Conclusions/Significance Taken together, our data reveal a novel mechanism by which mammalian cells control mitochondrial fusion. In addition, we describe a novel role of PGC-1β in mitochondrial physiology, namely the control of mitochondrial fusion mainly through Mfn2. PMID:18974884

  7. Structural Basis for the Recognition Between HIV-1 Integrase and Transcriptional Coactivator p75

    SciTech Connect

    Cherepanov,P.; Ambrosio, A.; Rahman, S.; Ellenberger, T.; Engelman, A.

    2005-01-01

    Integrase (IN) is an essential retroviral enzyme, and human transcriptional coactivator p75, which is also referred to as lens epithelium-derived growth factor (LEDGF), is the dominant cellular binding partner of HIV-1 IN. Here, we report the crystal structure of the dimeric catalytic core domain of HIV-1 IN complexed to the IN-binding domain of LEDGF. Previously identified LEDGF hotspot residues anchor the protein to both monomers at the IN dimer interface. The principal structural features of IN that are recognized by the host factor are the backbone conformation of residues 168-171 from one monomer and a hydrophobic patch that is primarily comprised of {alpha}-helices 1 and 3 of the second IN monomer. Inspection of diverse retroviral primary and secondary sequence elements helps to explain the apparent lentiviral tropism of the LEDGF-IN interaction. Because the lethal phenotypes of HIV-1 mutant viruses unable to interact with LEDGF indicate that IN function is highly sensitive to perturbations of the structure around the LEDGF-binding site, we propose that small molecule inhibitors of the protein-protein interaction might similarly disrupt HIV-1 replication.

  8. Remodeling the clock: coactivators and signal transduction in the circadian clockworks.

    PubMed

    Weber, Frank

    2009-03-01

    Most organisms on earth such as cyanobacteria, fungi, plants, insects, animals, and humans synchronize their physiological and behavioral activities with the environmental cycles of day and night. Significant progress has been made in unraveling the genetic components that constitute a molecular circadian clock, which facilitates the temporal control of physiology and behavior. Clock genes assemble interlocked transcriptional/translational feedback loops that underlie the circadian oscillations. Recent investigations revealed that posttranslational regulation of clock proteins is crucial for functioning of the molecular oscillator and for precise temporal control of circadian transcription. This review provides an overview of the homologous clockworks in Drosophila and mammals, with a special focus on recent insights in the posttranslational regulation of clock proteins as well as the role of coactivators, repressors, and signal transduction for circadian controlled genome-wide transcription. The emerging mechanisms of clock gene regulation provide an understanding of the temporal control of transcription in general and the circadian orchestration of physiology and behavior in particular.

  9. Functional interaction between the HIV transactivator Tat and the transcriptional coactivator PC4 in T cells.

    PubMed

    Holloway, A F; Occhiodoro, F; Mittler, G; Meisterernst, M; Shannon, M F

    2000-07-14

    The human immunodeficiency virus (HIV) transactivator Tat is a potent activator of transcription from the HIV long terminal repeat and is essential for efficient viral gene expression and replication. Tat has been shown to interact with components of the basal transcription machinery and transcriptional activators. Here we identify the cellular coactivator PC4 as a Tat-interacting protein using the yeast two-hybrid system and confirmed this interaction both in vitro and in vivo by coimmunoprecipitation. We found that this interaction has a functional outcome in that PC4 overexpression enhanced activation of the HIV long terminal repeat in transient transfection studies in a Tat-dependent manner. The domains of PC4 and Tat required for the interaction were mapped. In vitro binding studies showed that the basic transactivation-responsive binding domain of Tat is required for the interaction with PC4. The minimum region of PC4 required for Tat binding was amino acids 22-91, whereas mutation of the lysine-rich domain between amino acids 22 and 43 prevented interaction with Tat. Tat-PC4 interactions may be controlled by phosphorylation, because phosphorylation of PC4 by casein kinase II inhibited interactions with Tat both in vivo and in vitro. We propose that PC4 may be involved in linking Tat to the basal transcription machinery.

  10. The tomato mosaic tobamovirus movement protein interacts with a putative transcriptional coactivator KELP.

    PubMed

    Matsushita, Y; Deguchi, M; Youda, M; Nishiguchi, M; Nyunoya, H

    2001-08-31

    Viral movement through plasmodesmata in host plants likely depends on the interaction between virus-encoded movement protein (MP) and host proteins. In order to search for MP-interacting protein (MIP), we carried out far-western screening of a Brassica campestris cDNA library using a recombinant MP of tomato mosaic tobamovirus (ToMV) as a probe. One of the positive clones, designated MIP102, was found to be a putative orthologue for a transcriptional coactivator KELP of Arabidopsis thaliana. In vitro analysis with recombinant proteins revealed that ToMV MP could bind to KELP proteins that are derived from different plant species. At least 31 amino acids from the carboxyl-terminus of ToMV MP were dispensable for the interaction with KELP. Other MPs, derived from crucifer tobamovirus CTMV-W and cucumber mosaic cucumovirus, also exhibited comparable binding abilities. This suggests that these MPs could commonly interact with KELP, possibly to modulate the host gene expression.

  11. Impairment of voluntary control of finger motion following stroke: role of inappropriate muscle coactivation.

    PubMed

    Kamper, D G; Rymer, W Z

    2001-05-01

    Subjects with chronic hemiplegia following stroke attempted to perform voluntary isometric, isokinetic, and free contractions of the extensor muscles of the metacarpophalangeal (MCP) joints. We recorded torque, metacarpophalangeal joint angle and velocity, and electromyographic (EMG) activity of the extrinsic extensors and flexors and the first dorsal interosseous (FDI). We found that voluntary MCP joint extension in hemiparetic subjects was greatly impaired in comparison with control subjects: only two of the 11 stroke subjects were able to generate even 0.21 N-m of isometric extension torque, only two could produce positive finger extension with no load, and none could develop an isokinetic concentric extension. Deficits seemed to result from a combination of coactivation of the finger flexor and extensor muscles and decreased voluntary excitation of the extensors, as normalized flexor and FDI EMG activity were greater for stroke than for control subjects (P < 0.001), but normalized extensor activity was reduced (P < 0.001). Copyright 2001 John Wiley & Sons, Inc.

  12. Body Dissatisfaction in Early Adolescence: The Coactive Roles of Cognitive and Sociocultural Factors.

    PubMed

    Saunders, Jessica F; Frazier, Leslie D

    2017-06-01

    The sociocultural influences of the media, friends, and family on body dissatisfaction in young girls are well documented, yet further increasing our comprehension of the coaction of cognitive processes with sociocultural factors is crucial to understanding the dynamic emergence of body dissatisfaction in early adolescence. The current study examined the roles of appearance related messages and expectations from friends and family and selective attention biases in the development of body dissatisfaction. An ethnically and racially diverse sample of girls (72 % Hispanic White, 17.8 % African-American, 8.5 % non-Hispanic White, and 1.7 % Asian-American) between the ages of 9 and 13 (N = 118) completed multiple measures of attention, sociocultural attitudes toward weight and shape, and body dissatisfaction. The data from these measures were examined using path analysis. The final model fit well, and demonstrated the coactive effect of selective attention and sociocultural factors on body dissatisfaction. These findings will be instrumental in designing future body dissatisfaction intervention and prevention programs that incorporate cognitive factors, augmenting the existing sociocultural and psycho-educational frameworks.

  13. Abscisic acid promotes proteasome-mediated degradation of the transcription coactivator NPR1 in Arabidopsis thaliana.

    PubMed

    Ding, Yezhang; Dommel, Matthew; Mou, Zhonglin

    2016-04-01

    Proteasome-mediated turnover of the transcription coactivator NPR1 is pivotal for efficient activation of the broad-spectrum plant immune responses known as localized acquired resistance (LAR) and systemic acquired resistance (SAR) in adjacent and systemic tissues, respectively, and requires the CUL3-based E3 ligase and its adaptor proteins, NPR3 and NPR4, which are receptors for the signaling molecule salicylic acid (SA). It has been shown that SA prevents NPR1 turnover under non-inducing and LAR/SAR-inducing conditions, but how cellular NPR1 homeostasis is maintained remains unclear. Here, we show that the phytohormone abscisic acid (ABA) and SA antagonistically influence cellular NPR1 protein levels. ABA promotes NPR1 degradation via the CUL3(NPR) (3/) (NPR) (4) complex-mediated proteasome pathway, whereas SA may protect NPR1 from ABA-promoted degradation through phosphorylation. Furthermore, we demonstrate that the timing and strength of SA and ABA signaling are critical in modulating NPR1 accumulation and target gene expression. Perturbing ABA or SA signaling in adjacent tissues alters the temporal dynamic pattern of NPR1 accumulation and target gene transcription. Finally, we show that sequential SA and ABA treatment leads to dynamic changes in NPR1 protein levels and target gene expression. Our results revealed a tight correlation between sequential SA and ABA signaling and dynamic changes in NPR1 protein levels and NPR1-dependent transcription in plant immune responses. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  14. Proteasome-Mediated Degradation of the Coactivator p300 Impairs Cardiac Transcription

    PubMed Central

    Poizat, Coralie; Sartorelli, Vittorio; Chung, Gene; Kloner, Robert A.; Kedes, Larry

    2000-01-01

    The transcription of tissue-specific genes is controlled by regulatory factors and cofactors and is suppressed in cardiac cells by the antineoplastic agent doxorubicin. Here we show that exposure of cultured cardiomyocytes to doxorubicin resulted in the rapid depletion of transcripts for MEF2C, dHAND, and NKX2.5, three pivotal regulators of cardiac gene expression. Delivery of exogenous p300, a coactivator of MEF2C and NKX2.5 in cardiomyocytes, restored cardiac transcription despite the presence of doxorubicin. Furthermore, p300 also restored the accumulation of transcripts for MEF2C itself. Importantly, cardiocytes exposed to doxorubicin displayed reduced levels of p300 proteins. This was not due to alterations in the level of p300 transcripts; rather, and surprisingly, doxorubicin promoted selective degradation of p300 mediated by the 26S-proteasome machinery. Doxorubicin had no effect on the general level of ubiquitinated proteins or on the levels of β-catenin, a protein known to be degraded by proteasome-mediated degradation. These results provide evidence for a new mechanism of transcriptional repression caused by doxorubicin in which the selective degradation of p300 results in reduced p300-dependent transcription, including production of MEF2C mRNA. PMID:11073966

  15. Androgen Receptor Coactivator ARID4B Is Required for the Function of Sertoli Cells in Spermatogenesis.

    PubMed

    Wu, Ray-Chang; Zeng, Yang; Pan, I-Wen; Wu, Mei-Yi

    2015-09-01

    Defects in spermatogenesis, a process that produces spermatozoa inside seminiferous tubules of the testis, result in male infertility. Spermatogenic progression is highly dependent on a microenvironment provided by Sertoli cells, the only somatic cells and epithelium of seminiferous tubules. However, genes that regulate such an important activity of Sertoli cells are poorly understood. Here, we found that AT-rich interactive domain 4B (ARID4B), is essential for the function of Sertoli cells to regulate spermatogenesis. Specifically, we generated Sertoli cell-specific Arid4b knockout (Arid4bSCKO) mice, and showed that the Arid4bSCKO male mice were completely infertile with impaired testis development and significantly reduced testis size. Importantly, severe structural defects accompanied by loss of germ cells and Sertoli cell-only phenotype were found in many seminiferous tubules of the Arid4bSCKO testes. In addition, maturation of Sertoli cells was significantly delayed in the Arid4bSCKO mice, associated with delayed onset of spermatogenesis. Spermatogenic progression was also defective, showing an arrest at the round spermatid stage in the Arid4bSCKO testes. Interestingly, we showed that ARID4B functions as a "coactivator" of androgen receptor and is required for optimal transcriptional activation of reproductive homeobox 5, an androgen receptor target gene specifically expressed in Sertoli cells and critical for spermatogenesis. Together, our study identified ARID4B to be a key regulator of Sertoli cell function important for male germ cell development.

  16. Introducing co-activation pattern metrics to quantify spontaneous brain network dynamics.

    PubMed

    Chen, Jingyuan E; Chang, Catie; Greicius, Michael D; Glover, Gary H

    2015-05-01

    Recently, fMRI researchers have begun to realize that the brain's intrinsic network patterns may undergo substantial changes during a single resting state (RS) scan. However, despite the growing interest in brain dynamics, metrics that can quantify the variability of network patterns are still quite limited. Here, we first introduce various quantification metrics based on the extension of co-activation pattern (CAP) analysis, a recently proposed point-process analysis that tracks state alternations at each individual time frame and relies on very few assumptions; then apply these proposed metrics to quantify changes of brain dynamics during a sustained 2-back working memory (WM) task compared to rest. We focus on the functional connectivity of two prominent RS networks, the default-mode network (DMN) and executive control network (ECN). We first demonstrate less variability of global Pearson correlations with respect to the two chosen networks using a sliding-window approach during WM task compared to rest; then we show that the macroscopic decrease in variations in correlations during a WM task is also well characterized by the combined effect of a reduced number of dominant CAPs, increased spatial consistency across CAPs, and increased fractional contributions of a few dominant CAPs. These CAP metrics may provide alternative and more straightforward quantitative means of characterizing brain network dynamics than time-windowed correlation analyses.

  17. The tumor suppressor Nf2 regulates corpus callosum development by inhibiting the transcriptional coactivator Yap

    PubMed Central

    Lavado, Alfonso; Ware, Michelle; Paré, Joshua; Cao, Xinwei

    2014-01-01

    The corpus callosum connects cerebral hemispheres and is the largest axon tract in the mammalian brain. Callosal malformations are among the most common congenital brain anomalies and are associated with a wide range of neuropsychological deficits. Crossing of the midline by callosal axons relies on a proper midline environment that harbors guidepost cells emitting guidance cues to instruct callosal axon navigation. Little is known about what controls the formation of the midline environment. We find that two components of the Hippo pathway, the tumor suppressor Nf2 (Merlin) and the transcriptional coactivator Yap (Yap1), regulate guidepost development and expression of the guidance cue Slit2 in mouse. During normal brain development, Nf2 suppresses Yap activity in neural progenitor cells to promote guidepost cell differentiation and prevent ectopic Slit2 expression. Loss of Nf2 causes malformation of midline guideposts and Slit2 upregulation, resulting in callosal agenesis. Slit2 heterozygosity and Yap deletion both restore callosal formation in Nf2 mutants. Furthermore, selectively elevating Yap activity in midline neural progenitors is sufficient to disrupt guidepost formation, upregulate Slit2 and prevent midline crossing. The Hippo pathway is known for its role in controlling organ growth and tumorigenesis. Our study identifies a novel role of this pathway in axon guidance. Moreover, by linking axon pathfinding and neural progenitor behaviors, our results provide an example of the intricate coordination between growth and wiring during brain development. PMID:25336744

  18. Sox15 and Fhl3 transcriptionally coactivate Foxk1 and regulate myogenic progenitor cells

    PubMed Central

    Meeson, Annette P; Shi, Xiaozhong; Alexander, Matthew S; Williams, R S; Allen, Ronald E; Jiang, Nan; Adham, Ibrahim M; Goetsch, Sean C; Hammer, Robert E; Garry, Daniel J

    2007-01-01

    The regulation of myogenic progenitor cells during muscle regeneration is not clearly understood. We have previously shown that the Foxk1 gene, a member of the forkhead/winged helix family of transcription factors, is expressed in myogenic progenitor cells in adult skeletal muscle. In the present study, we utilize transgenic technology and demonstrate that the 4.6 kb upstream fragment of the Foxk1 gene directs β-galactosidase expression to the myogenic progenitor cell population. We further establish that Sox15 directs Foxk1 expression to the myogenic progenitor cell population, as it binds to an evolutionarily conserved site and recruits Fhl3 to transcriptionally coactivate Foxk1 gene expression. Knockdown of endogenous Sox15 results in perturbed cell cycle kinetics and decreased Foxk1 expression. Furthermore, Sox15 mutant mice display perturbed skeletal muscle regeneration, due in part to decreased numbers of satellite cells and decreased Foxk1 expression. These studies demonstrate that Sox15, Fhl3 and Foxk1 function to coordinately regulate the myogenic progenitor cell population and skeletal muscle regeneration. PMID:17363903

  19. A C-Terminal Acidic Domain Regulates Degradation of the Transcriptional Coactivator Bob1

    PubMed Central

    Wong, Christina S. F.; Möller, Andreas

    2013-01-01

    Bob1 (Obf-1 or OCA-B) is a 34-kDa transcriptional coactivator encoded by the Pou2af1 gene that is essential for normal B-cell development and immune responses in mice. During lymphocyte activation, Bob1 protein levels dramatically increase independently of mRNA levels, suggesting that the stability of Bob1 is regulated. We used a fluorescent protein-based reporter system to analyze protein stability in response to genetic and physiological perturbations and show that, while Bob1 degradation is proteasome mediated, it does not require ubiquitination of Bob1. Furthermore, degradation of Bob1 in B cells appears to be largely independent of the E3 ubiquitin ligase Siah. We propose a novel mechanism of Bob1 turnover in B cells, whereby an acidic region in the C terminus of Bob1 regulates the activity of degron signals elsewhere in the protein. Changes that make the C terminus more acidic, including tyrosine phosphorylation-mimetic mutations, stabilize the instable murine Bob1 protein, indicating that B cells may regulate Bob1 stability and activity via signaling pathways. Finally, we show that expressing a stable Bob1 mutant in B cells suppresses cell proliferation and induces changes in surface marker expression commonly seen during B-cell differentiation. PMID:24061476

  20. Creb coactivators direct anabolic responses and enhance performance of skeletal muscle

    PubMed Central

    Bruno, Nelson E; Kelly, Kimberly A; Hawkins, Richard; Bramah-Lawani, Mariam; Amelio, Antonio L; Nwachukwu, Jerome C; Nettles, Kendall W; Conkright, Michael D

    2014-01-01

    During the stress response to intense exercise, the sympathetic nervous system (SNS) induces rapid catabolism of energy reserves through the release of catecholamines and subsequent activation of protein kinase A (PKA). Paradoxically, chronic administration of sympathomimetic drugs (β-agonists) leads to anabolic adaptations in skeletal muscle, suggesting that sympathetic outflow also regulates myofiber remodeling. Here, we show that β-agonists or catecholamines released during intense exercise induce Creb-mediated transcriptional programs through activation of its obligate coactivators Crtc2 and Crtc3. In contrast to the catabolic activity normally associated with SNS function, activation of the Crtc/Creb transcriptional complex by conditional overexpression of Crtc2 in the skeletal muscle of transgenic mice fostered an anabolic state of energy and protein balance. Crtc2-overexpressing mice have increased myofiber cross-sectional area, greater intramuscular triglycerides and glycogen content. Moreover, maximal exercise capacity was enhanced after induction of Crtc2 expression in transgenic mice. Collectively these findings demonstrate that the SNS-adrenergic signaling cascade coordinates a transient catabolic stress response during high-intensity exercise, which is followed by transcriptional reprogramming that directs anabolic changes for recovery and that augments subsequent exercise performance. PMID:24674967

  1. SIRT6 safeguards human mesenchymal stem cells from oxidative stress by coactivating NRF2

    PubMed Central

    Pan, Huize; Guan, Di; Liu, Xiaomeng; Li, Jingyi; Wang, Lixia; Wu, Jun; Zhou, Junzhi; Zhang, Weizhou; Ren, Ruotong; Zhang, Weiqi; Li, Ying; Yang, Jiping; Hao, Ying; Yuan, Tingting; Yuan, Guohong; Wang, Hu; Ju, Zhenyu; Mao, Zhiyong; Li, Jian; Qu, Jing; Tang, Fuchou; Liu, Guang-Hui

    2016-01-01

    SIRT6 belongs to the mammalian homologs of Sir2 histone NAD+-dependent deacylase family. In rodents, SIRT6 deficiency leads to aging-associated degeneration of mesodermal tissues. It remains unknown whether human SIRT6 has a direct role in maintaining the homeostasis of mesodermal tissues. To this end, we generated SIRT6 knockout human mesenchymal stem cells (hMSCs) by targeted gene editing. SIRT6-deficient hMSCs exhibited accelerated functional decay, a feature distinct from typical premature cellular senescence. Rather than compromised chromosomal stability, SIRT6-null hMSCs were predominately characterized by dysregulated redox metabolism and increased sensitivity to the oxidative stress. In addition, we found SIRT6 in a protein complex with both nuclear factor erythroid 2-related factor 2 (NRF2) and RNA polymerase II, which was required for the transactivation of NRF2-regulated antioxidant genes, including heme oxygenase 1 (HO-1). Overexpression of HO-1 in SIRT6-null hMSCs rescued premature cellular attrition. Our study uncovers a novel function of SIRT6 in maintaining hMSC homeostasis by serving as a NRF2 coactivator, which represents a new layer of regulation of oxidative stress-associated stem cell decay. PMID:26768768

  2. Remodeling the clock: coactivators and signal transduction in the circadian clockworks

    NASA Astrophysics Data System (ADS)

    Weber, Frank

    2009-03-01

    Most organisms on earth such as cyanobacteria, fungi, plants, insects, animals, and humans synchronize their physiological and behavioral activities with the environmental cycles of day and night. Significant progress has been made in unraveling the genetic components that constitute a molecular circadian clock, which facilitates the temporal control of physiology and behavior. Clock genes assemble interlocked transcriptional/translational feedback loops that underlie the circadian oscillations. Recent investigations revealed that posttranslational regulation of clock proteins is crucial for functioning of the molecular oscillator and for precise temporal control of circadian transcription. This review provides an overview of the homologous clockworks in Drosophila and mammals, with a special focus on recent insights in the posttranslational regulation of clock proteins as well as the role of coactivators, repressors, and signal transduction for circadian controlled genome-wide transcription. The emerging mechanisms of clock gene regulation provide an understanding of the temporal control of transcription in general and the circadian orchestration of physiology and behavior in particular.

  3. Adaptations of skeletal muscle to exercise: rapid increase in the transcriptional coactivator PGC-1.

    PubMed

    Baar, Keith; Wende, Adam R; Jones, Terry E; Marison, Matthew; Nolte, Lorraine A; Chen, May; Kelly, Daniel P; Holloszy, John O

    2002-12-01

    Endurance exercise induces increases in mitochondria and the GLUT4 isoform of the glucose transporter in muscle. Although little is known about the mechanisms underlying these adaptations, new information has accumulated regarding how mitochondrial biogenesis and GLUT4 expression are regulated. This includes the findings that the transcriptional coactivator PGC-1 promotes mitochondrial biogenesis and that NRF-1 and NRF-2 act as transcriptional activators of genes encoding mitochondrial enzymes. We tested the hypothesis that increases in PGC-1, NRF-1, and NRF-2 are involved in the initial adaptive response of muscle to exercise. Five daily bouts of swimming induced increases in mitochondrial enzymes and GLUT4 in skeletal muscle in rats. One exercise bout resulted in approximately twofold increases in full-length muscle PGC-1 mRNA and PGC-1 protein, which were evident 18 h after exercise. A smaller form of PGC-1 increased after exercise. The exercise induced increases in muscle NRF-1 and NRF-2 that were evident 12 to 18 h after one exercise bout. These findings suggest that increases in PGC-1, NRF-1, and NRF-2 represent key regulatory components of the stimulation of mitochondrial biogenesis by exercise and that PGC-1 mediates the coordinated increases in GLUT4 and mitochondria.

  4. The Insulin-Regulated CREB Coactivator TORC Promotes Stress Resistance in Drosophila

    PubMed Central

    Wang, Biao; Goode, Jason; Best, Jennifer; Meltzer, Jodi; Schilman, Pablo E.; Chen, Jian; Garza, Dan; Thomas, John B.; Montminy, Marc

    2013-01-01

    SUMMARY In fasted mammals, glucose homeostasis is maintained through induction of the cAMP response element-binding protein (CREB) coactivator transducer of regulated CREB activity 2 (TORC2), which stimulates the gluconeogenic program in concert with the forkhead factor FOXO1. Here we show that starvation also triggers TORC activation in Drosophila, where it maintains energy balance through induction of CREB target genes in the brain. TORC mutant flies have reduced glycogen and lipid stores and are sensitive to starvation and oxidative stress. Neuronal TORC expression rescued stress sensitivity as well as CREB target gene expression in TORC mutants. During refeeding, increases in insulin signaling inhibited TORC activity through the salt-inducible kinase 2 (SIK2)-mediated phosphorylation and subsequent degradation of TORC. Depletion of neuronal SIK2 increased TORC activity and enhanced stress resistance. As disruption of insulin signaling also augmented TORC activity in adult flies, our results illustrate the importance of an insulin-regulated pathway that functions in the brain to maintain energy balance. PMID:18460334

  5. Training through gametherapy promotes coactivation of the pelvic floor and abdominal muscles in young women, nulliparous and continents

    PubMed Central

    Silva, Valeria Regina; Riccetto, Cássio; Martinho, Natalia Miguel; Marques, Joseane; Carvalho, Leonardo Cesar; Botelho, Simone

    2016-01-01

    ABSTRACT Introduction and objectives: Several studies have been investigated co-activation can enhance the effectveness of PFM training protocols allowing preventive and therapeutic goals in pelvic floor dysfunctions. The objective of the present study was to investigate if an abdominal-pelvic protocol of training (APT) using gametherapy would allow co-activation of PFM and transversus abdominis/oblique internal (TrA/OI) muscles. Patients and methods: Twenty-five nulliparous, continent, young females, with median age 24.76 (±3.76) years were evaluated using digital palpation (DP) of PFM and surface electromyography of PFM and TrA/OI simultaneously, during maximal voluntary contraction (MVC), alternating PFM and TrA/OI contraction requests. All women participated on a supervised program of APT using gametherapy, that included exercises of pelvic mobilization associated to contraction of TrA/OI muscles oriented by virtual games, for 30 minutes, three times a week, in a total of 10 sessions. Electromyographic data were processed and analyzed by ANOVA - analysis of variance. Results: When MVC of TrA/OI was solicited, it was observed simultaneous increase of electromyographic activity of PFM (p=0.001) following ATP. However, EMG activity did not change significantly during MVC of PFM. Conclusion: Training using gametherapy allowed better co-activation of pelvic floor muscles in response to contraction of TrA, in young nulliparous and continent women. PMID:27564290

  6. Training through gametherapy promotes coactivation of the pelvic floor and abdominal muscles in young women, nulliparous and continents.

    PubMed

    Silva, Valeria Regina; Riccetto, Cássio Luis Zanettini; Martinho, Natalia Miguel; Marques, Joseane; Carvalho, Leonardo Cesar; Botelho, Simone

    2016-01-01

    several studies have been investigated co-activation can enhance the effectveness of PFM training protocols allowing preventive and therapeutic goals in pelvic floor dysfunctions. The objective of the present study was to investigate if an abdominal-pelvic protocol of training (APT) using gametherapy would allow co-activation of PFM and transversus abdominis/oblique internal (TrA/OI) muscles. Twenty-five nulliparous, continent, young females, with median age 24.76 (±3.76) years were evaluated using digital palpation (DP) of PFM and surfasse electromyography of PFM and TrA/OI simultaneously, during maximal voluntary contraction (MVC), alternating PFM and TrA/OI contraction requests. All women participated on a supervised program of APT using gametherapy, that included exercises of pelvic mobilization associated to contraction of TrA/OI muscles oriented by virtual games, for 30 minutes, three times a week, in a total of 10 sessions. Electromyographic data were processed and analyzed by ANOVA - analysis of variance. When MVC of TrA/OI was solicited, it was observed simultaneous increase of electromyographic activity of PFM (p=0.001) following ATP. However, EMG activity did not change significantly during MVC of PFM. Training using gametherapy allowed better co-activation of pelvic floor muscles in response to contraction of TrA, in young nulliparous and continent women. Copyright© by the International Brazilian Journal of Urology.

  7. [RAC3 nuclear receptor co-activator has a protective role in the apoptosis induced by different stimuli].

    PubMed

    Coló, Georgina P; Rubio, María F; Alvarado, Cecilia V; Costas, Mónica A

    2007-01-01

    RAC3 belongs to the family of p160 nuclear receptors coactivators and it is over-expressed in several tumors. We have previously shown that RAC3 is a NF-kappaB coactivator. In this paper, we investigated the role of RAC3 in cell-sensitivity to apoptosis, using H2O2 in the human embryonic kidney cell line (HEK293), and tumor necrosis factor-related apoptosis inducing ligand (TRAIL) in a human chronic myeloid leukemia cell line (K562) naturally resistant to TRAIL. We observed that the tumoral K562 cells have high levels of RAC3 if compared with the non-tumoral HEK293 cells. The normal or transfected coactivator over-expression inhibits apoptosis through a diminished caspase activity and AIF nuclear translocation, increased NF-kappaB, AKT and p38, and decreased ERK activities. In contrast, inhibition of RAC3 by siRNA induced sensitivity of K562 to TRAIL-induced apoptosis. Such results suggest that over-expression of RAC3 contributes to tumor development through molecular mechanisms that do not depend strictly on acetylation and/or steroid hormones, which control cell death. This could be a possible target for future tumor therapies.

  8. Looking into Children's Play Communities

    ERIC Educational Resources Information Center

    Mabry, Mark; Fucigna, Carolee

    2009-01-01

    Play, particularly children's sociodramatic play, is the cornerstone of early childhood classrooms in the United States. Early childhood educators learn and expound mantras of "the value of play," "play-based programs," "children learning through play," and "play as child's work." They strive to promote the importance of making a place for play in…

  9. Playing with Light.

    ERIC Educational Resources Information Center

    Cavicchi, Elizabeth; Lucht, Petra; Hughes-McDonnell, Fiona

    2000-01-01

    Challenges the belief that high stakes tests are the keystone of students' educational attainment, describing a series of exploratory workshops, developed in reaction to this issue, in which teachers (as essential preparation for developing students' curiosity) deepened their understanding of the principles of physics by playing with light. Such…

  10. Playing To Learn.

    ERIC Educational Resources Information Center

    Mann, Dale; Shakeshaft, Charol; Kottkamp, Robert; Becker, Jonathan

    2000-01-01

    A study to determine effects of Lightspan Partnership Inc.'s interactive materials on student achievement in a Denver- area elementary school revealed higher reading and math test scores for Lightspan schools, compared to control schools. This serious play curriculum, assisted by parents, benefited neediest kids most. (MLH)

  11. Bicentennial Plays and Programs.

    ERIC Educational Resources Information Center

    Fisher, Aileen

    This book contains royalty-free material on bicentennial themes for presentation by schools and amateur groups. The first section, Plays and Pageants, contains "Our Great Declaration,""A Star for Old Glory,""Sing, America, Sing,""Washington Marches On,""When Freedom Was News," and "A Dish of…

  12. Play's Importance in School

    ERIC Educational Resources Information Center

    Sandberg, Anette; Heden, Rebecca

    2011-01-01

    The purpose of this study is to contribute knowledge on and gain an understanding of elementary school teachers' perspectives on the function of play in children's learning processes. The study is qualitative with a hermeneutical approach and has George Herbert Mead as a theoretical frame of reference. Interviews have been carried out with seven…

  13. Games Professors Play

    ERIC Educational Resources Information Center

    Kenny, James A.; Herzing, Thomas W.

    1969-01-01

    The games are Build a Reputation (REP), Confuse the Student (CON), Blame the Opposition (BOP), and Pass the Buck (BUCK). Professors play these games because they "want to show off on occasion, . . . want to get off the hook and avoid responsibility, . . . are prone to blame others, or simply because they are lazy. (WM)

  14. Creative Outdoor Play Areas.

    ERIC Educational Resources Information Center

    Miller, Peggy L.

    Considering the creation of proper play areas for children (school sites, municipal and mini parks, private homes and backyards, shopping centers, apartment complexes, recreational areas, roadside parks, nursery schools, churches, summer camps, and drive-in theaters) as one of today's major challenges, the author recommends that professional…

  15. Creative Outdoor Play Areas.

    ERIC Educational Resources Information Center

    Miller, Peggy L.

    Considering the creation of proper play areas for children (school sites, municipal and mini parks, private homes and backyards, shopping centers, apartment complexes, recreational areas, roadside parks, nursery schools, churches, summer camps, and drive-in theaters) as one of today's major challenges, the author recommends that professional…

  16. Play's Importance in School

    ERIC Educational Resources Information Center

    Sandberg, Anette; Heden, Rebecca

    2011-01-01

    The purpose of this study is to contribute knowledge on and gain an understanding of elementary school teachers' perspectives on the function of play in children's learning processes. The study is qualitative with a hermeneutical approach and has George Herbert Mead as a theoretical frame of reference. Interviews have been carried out with seven…

  17. Integrated Play Groups

    ERIC Educational Resources Information Center

    Glovak, Sandra

    2007-01-01

    As an occupational therapist running social play groups with sensory integration for children on the autism spectrum, the author frequently doubted the wisdom of combining several children on the spectrum into a group. In fact, as the owner of a clinic she said, "No more!" The groups seemed like a waste of parents' time and money, and she refused…

  18. "Playing" with Science

    ERIC Educational Resources Information Center

    Allen, Dave

    2012-01-01

    When faced with a multitude of tasks, any opportunity to "kill two birds with one stone" is welcome. Drama has always excited the author: as a child performing in plays, later as a student and now as a teacher directing performances and improvising within lessons. The author was lucky enough to have inspirational teachers during his…

  19. Playing with Science

    ERIC Educational Resources Information Center

    Vieyra, Rebecca; Edwards, Teon; Rowe, Elizabeth; Asbell-Clarke, Jodi

    2015-01-01

    Gaming is becoming an effective form of learning and assessment and shouldn't be overlooked in an increasingly technological world. The games described in this article ("Impulse," "Quantum Spectre," and "Ravenous"), entertaining enough to be played by the general public, are also appropriate and useful in a classroom…

  20. Integrated Play Groups

    ERIC Educational Resources Information Center

    Glovak, Sandra

    2007-01-01

    As an occupational therapist running social play groups with sensory integration for children on the autism spectrum, the author frequently doubted the wisdom of combining several children on the spectrum into a group. In fact, as the owner of a clinic she said, "No more!" The groups seemed like a waste of parents' time and money, and she refused…

  1. Playing It Safe.

    ERIC Educational Resources Information Center

    Jones, Rebecca

    1997-01-01

    Offers tips for avoiding sports-related injuries: (1) expect more of coaches; (2) develop an athletic-safety plan; (3) consider hiring an athletic trainer; (4) check facilities and equipment regularly; (5) recognize athletes' limitations; (6) take precautions beyond the playing field; and (7) check liability coverage and obtain informed consent.…

  2. Children as Playing Citizens

    ERIC Educational Resources Information Center

    Grindheim, Liv Torunn

    2017-01-01

    In this article, play is understood as activities of major importance for child-citizens and as activities that constitute various ways of participating. The researcher joined children in three early childhood education institutions in Norway in their activities and categorised their participation in their everyday life. The study depicts that, in…

  3. The Paradoxes of Play.

    ERIC Educational Resources Information Center

    Rokosz, Francis M.

    1988-01-01

    The article makes a case against the structuring of intramural sports programs on the basis of the varsity athletics model, arguing that the latter model's components of competition and aggression mar the former's intrinsic rewards of play, creativity, and enhanced human relationships. (CB)

  4. "Playing" with Science

    ERIC Educational Resources Information Center

    Allen, Dave

    2012-01-01

    When faced with a multitude of tasks, any opportunity to "kill two birds with one stone" is welcome. Drama has always excited the author: as a child performing in plays, later as a student and now as a teacher directing performances and improvising within lessons. The author was lucky enough to have inspirational teachers during his…

  5. Playing with Science

    ERIC Educational Resources Information Center

    Vieyra, Rebecca; Edwards, Teon; Rowe, Elizabeth; Asbell-Clarke, Jodi

    2015-01-01

    Gaming is becoming an effective form of learning and assessment and shouldn't be overlooked in an increasingly technological world. The games described in this article ("Impulse," "Quantum Spectre," and "Ravenous"), entertaining enough to be played by the general public, are also appropriate and useful in a classroom…

  6. One Play a Day

    ERIC Educational Resources Information Center

    Blankenship, Mark

    2007-01-01

    Undergraduate theater students rarely get the chance to work on a major world premiere, but this year hundreds of them will. Currently, more than 70 colleges and universities are participating in "365 Days/365 Plays," an ambitious project from Pulitzer Prize-winning playwright Suzan-Lori Parks. Every week, as they mount their portion of this epic…

  7. Abstraction through Game Play

    ERIC Educational Resources Information Center

    Avraamidou, Antri; Monaghan, John; Walker, Aisha

    2012-01-01

    This paper examines the computer game play of an 11-year-old boy. In the course of building a virtual house he developed and used, without assistance, an artefact and an accompanying strategy to ensure that his house was symmetric. We argue that the creation and use of this artefact-strategy is a mathematical abstraction. The discussion…

  8. One Play a Day

    ERIC Educational Resources Information Center

    Blankenship, Mark

    2007-01-01

    Undergraduate theater students rarely get the chance to work on a major world premiere, but this year hundreds of them will. Currently, more than 70 colleges and universities are participating in "365 Days/365 Plays," an ambitious project from Pulitzer Prize-winning playwright Suzan-Lori Parks. Every week, as they mount their portion of this epic…

  9. The Novel SLIK Histone Acetyltransferase Complex Functions in the Yeast Retrograde Response Pathway

    PubMed Central

    Pray-Grant, Marilyn G.; Schieltz, David; McMahon, Stacey J.; Wood, Jennifer M.; Kennedy, Erin L.; Cook, Richard G.; Workman, Jerry L.; Yates III, John R.; Grant, Patrick A.

    2002-01-01

    The SAGA complex is a conserved histone acetyltransferase-coactivator that regulates gene expression in Saccharomyces cerevisiae. SAGA contains a number of subunits known to function in transcription including Spt and Ada proteins, the Gcn5 acetyltransferase, a subset of TATA-binding-protein-associated factors (TAFIIs), and Tra1. Here we report the identification of SLIK (SAGA-like), a complex related in composition to SAGA. Notably SLIK uniquely contains the protein Rtg2, linking the function of SLIK to the retrograde response pathway. Yeast harboring mutations in both SAGA and SLIK complexes displays synthetic phenotypes more severe than those of yeast with mutation of either complex alone. We present data indicating that distinct forms of the SAGA complex may regulate specific subsets of genes and that SAGA and SLIK have multiple partly overlapping activities, which play a critical role in transcription by RNA polymerase II. PMID:12446794

  10. Viewpoints: The High School Play.

    ERIC Educational Resources Information Center

    Harbison, Lawrence; And Others

    1981-01-01

    Presents opinions of professionals on the current state of the high school play. Participants include a playwright, play supplier, high school theater instructor, workshop leader, and play publisher. Discusses selection, production, and performance of plays. (JMF)

  11. Towards an automated selection of spontaneous co-activity maps in functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Sourty, Marion; Thoraval, Laurent; Roquet, Daniel; Armspach, Jean-Paul; Foucher, Jack

    2015-03-01

    Functional magnetic resonance imaging allows to assess large scale functional integration of the brain. One of the leading techniques to extract functionally relevant networks is spatial independent component analysis (ICA). Spatial ICA separates independent spatial sources, many of whom are noise or imaging artifacts, whereas some do correspond to functionally relevant Spontaneous co-Activity Maps (SAMs). For research purposes, ICA is generally performed on group data. This strategy is well adapted to uncover commonly shared networks, e.g. resting-state networks, but fails to capture idiosyncratic functional networks which may be related to pathological activity, e.g. epilepsy, hallucinations. To capture these subject specific networks, ICA has to be applied to single subjects using a large number of components, from which a tenth are SAMs. Up to now, SAMs have to be selected manually by an expert based on predefined criteria. We aim to semi-automate the selection process in order to save time. To this end, some approaches have been proposed but none with the near 100 % sensitivity required for clinical purposes. In this paper, we propose a computerized version of the SAM's criteria used by experts, based on frequential and spatial characteristics of functional networks. Here we present a pre-selection method and its results at different resolutions, with different scanners or imaging sequences. While preserving a near 100 % sensitivity, it allows an average of 70 % reduction of components to be classified which save 55% of experts' time. In comparison, group ICA fails to detect about 25% of the SAMs.

  12. Pbx-Hox heterodimers recruit coactivator-corepressor complexes in an isoform-specific manner.

    PubMed

    Asahara, H; Dutta, S; Kao, H Y; Evans, R M; Montminy, M

    1999-12-01

    Homeobox (hox) proteins have been shown to regulate cell fate and segment identity by promoting the expression of specific genetic programs. In contrast to their restricted biological action in vivo, however, most homeodomain factors exhibit promiscuous DNA binding properties in vitro, suggesting a requirement for additional cofactors that enhance target site selectivity. In this regard, the pbx family of homeobox genes has been found to heterodimerize with and thereby augment the DNA binding activity of certain hox proteins on a subset of potential target sites. Here we examine the transcriptional properties of a forced hox-pbx heterodimer containing the pancreas-specific orphan homeobox factor pdx fused to pbx-1a. Compared to the pdx monomer, the forced pdx-pbx1a dimer, displayed 10- to 20-fold-higher affinity for a consensus hox-pbx binding site but was completely unable to bind a hox monomer recognition site. The pdx-pbx dimer stimulated target gene expression via an N-terminal trans-activation domain in pdx that interacts with the coactivator CREB binding protein. The pdx-pbx dimer was also found to repress transcription via a C-terminal domain in pbx-1a that associates with the corepressors SMRT and NCoR. The transcriptional properties of the pdx-pbx1 complex appear to be regulated at the level of alternative splicing; a pdx-pbx polypeptide containing the pbx1b isoform, which lacks the C-terminal extension in pbx1a, was unable to repress target gene expression via NCoR-SMRT. Since pbx1a and pbx1b are differentially expressed in endocrine versus exocrine compartments of the adult pancreas, our results illustrate a novel mechanism by which pbx proteins may modulate the expression of specific genetic programs, either positively or negatively, during development.

  13. Pbx-Hox Heterodimers Recruit Coactivator-Corepressor Complexes in an Isoform-Specific Manner

    PubMed Central

    Asahara, Hiroshi; Dutta, Sanjoy; Kao, Hung-Ying; Evans, Ronald M.; Montminy, Marc

    1999-01-01

    Homeobox (hox) proteins have been shown to regulate cell fate and segment identity by promoting the expression of specific genetic programs. In contrast to their restricted biological action in vivo, however, most homeodomain factors exhibit promiscuous DNA binding properties in vitro, suggesting a requirement for additional cofactors that enhance target site selectivity. In this regard, the pbx family of homeobox genes has been found to heterodimerize with and thereby augment the DNA binding activity of certain hox proteins on a subset of potential target sites. Here we examine the transcriptional properties of a forced hox-pbx heterodimer containing the pancreas-specific orphan homeobox factor pdx fused to pbx-1a. Compared to the pdx monomer, the forced pdx-pbx1a dimer, displayed 10- to 20-fold-higher affinity for a consensus hox-pbx binding site but was completely unable to bind a hox monomer recognition site. The pdx-pbx dimer stimulated target gene expression via an N-terminal trans-activation domain in pdx that interacts with the coactivator CREB binding protein. The pdx-pbx dimer was also found to repress transcription via a C-terminal domain in pbx-1a that associates with the corepressors SMRT and NCoR. The transcriptional properties of the pdx-pbx1 complex appear to be regulated at the level of alternative splicing; a pdx-pbx polypeptide containing the pbx1b isoform, which lacks the C-terminal extension in pbx1a, was unable to repress target gene expression via NCoR-SMRT. Since pbx1a and pbx1b are differentially expressed in endocrine versus exocrine compartments of the adult pancreas, our results illustrate a novel mechanism by which pbx proteins may modulate the expression of specific genetic programs, either positively or negatively, during development. PMID:10567547

  14. Crx activates opsin transcription by recruiting HAT-containing co-activators and promoting histone acetylation.

    PubMed

    Peng, Guang-Hua; Chen, Shiming

    2007-10-15

    The homeodomain transcription factor Crx is required for expression of many photoreceptor genes in the mammalian retina. The mechanism by which Crx activates transcription remains to be determined. Using protein-protein interaction assays, Crx was found to interact with three co-activator proteins (complexes): STAGA, Cbp and p300, all of which possess histone acetyl-transferase (HAT) activity. To determine the role of Crx-HAT interactions in target gene chromatin modification and transcriptional activation, quantitative RT-PCR and chromatin immunoprecipitation were performed on Crx target genes, rod and cone opsins, in developing mouse retina. Although cone opsins are transcribed earlier than rhodopsin during development, the transcription of each gene is preceded by the same sequence of events in their promoter and enhancer regions: (i) binding of Crx, followed by (ii) binding of HATs, (iii) the acetylation of histone H3, then (iv) binding of other photoreceptor transcription factors (Nrl and Nr2e3) and RNA polymerase II. In Crx knockout mice (Crx(-/-)), the association of HATs and AcH3 with target promoter/enhancer regions was significantly decreased, which correlates with aberrant opsin transcription and photoreceptor dysfunction in these mice. Similar changes to the opsin chromatin were seen in Y79 retinoblastoma cells, where opsin genes are barely transcribed. These defects in Y79 cells can be reversed by expressing a recombinant Crx or applying histone deacetylase inhibitors. Altogether, these results suggest that one mechanism for Crx-mediated transcriptional activation is to recruit HATs to photoreceptor gene chromatin for histone acetylation, thereby inducing and maintaining appropriate chromatin configurations for transcription.

  15. Autoimmune regulator is acetylated by transcription coactivator CBP/p300

    SciTech Connect

    Saare, Mario; Rebane, Ana; Rajashekar, Balaji; Vilo, Jaak; Peterson, Paert

    2012-08-15

    The Autoimmune Regulator (AIRE) is a regulator of transcription in the thymic medulla, where it controls the expression of a large set of peripheral-tissue specific genes. AIRE interacts with the transcriptional coactivator and acetyltransferase CBP and synergistically cooperates with it in transcriptional activation. Here, we aimed to study a possible role of AIRE acetylation in the modulation of its activity. We found that AIRE is acetylated in tissue culture cells and this acetylation is enhanced by overexpression of CBP and the CBP paralog p300. The acetylated lysines were located within nuclear localization signal and SAND domain. AIRE with mutations that mimicked acetylated K243 and K253 in the SAND domain had reduced transactivation activity and accumulated into fewer and larger nuclear bodies, whereas mutations that mimicked the unacetylated lysines were functionally similar to wild-type AIRE. Analogously to CBP, p300 localized to AIRE-containing nuclear bodies, however, the overexpression of p300 did not enhance the transcriptional activation of AIRE-regulated genes. Further studies showed that overexpression of p300 stabilized the AIRE protein. Interestingly, gene expression profiling revealed that AIRE, with mutations mimicking K243/K253 acetylation in SAND, was able to activate gene expression, although the affected genes were different and the activation level was lower from those regulated by wild-type AIRE. Our results suggest that the AIRE acetylation can influence the selection of AIRE activated genes. -- Highlights: Black-Right-Pointing-Pointer AIRE is acetylated by the acetyltransferases p300 and CBP. Black-Right-Pointing-Pointer Acetylation occurs between CARD and SAND domains and within the SAND domain. Black-Right-Pointing-Pointer Acetylation increases the size of AIRE nuclear dots. Black-Right-Pointing-Pointer Acetylation increases AIRE protein stability. Black-Right-Pointing-Pointer AIRE acetylation mimic regulates a different set of AIRE

  16. Steroid receptor coactivators 1 and 2 mediate fetal-to-maternal signaling that initiates parturition

    PubMed Central

    Gao, Lu; Rabbitt, Elizabeth H.; Condon, Jennifer C.; Renthal, Nora E.; Johnston, John M.; Mitsche, Matthew A.; Chambon, Pierre; Xu, Jianming; O’Malley, Bert W.; Mendelson, Carole R.

    2015-01-01

    The precise mechanisms that lead to parturition are incompletely defined. Surfactant protein-A (SP-A), which is secreted by fetal lungs into amniotic fluid (AF) near term, likely provides a signal for parturition; however, SP-A–deficient mice have only a relatively modest delay (~12 hours) in parturition, suggesting additional factors. Here, we evaluated the contribution of steroid receptor coactivators 1 and 2 (SRC-1 and SRC-2), which upregulate SP-A transcription, to the parturition process. As mice lacking both SRC-1 and SRC-2 die at birth due to respiratory distress, we crossed double-heterozygous males and females. Parturition was severely delayed (~38 hours) in heterozygous dams harboring SRC-1/-2–deficient embryos. These mothers exhibited decreased myometrial NF-κB activation, PGF2α, and expression of contraction-associated genes; impaired luteolysis; and elevated circulating progesterone. These manifestations also occurred in WT females bearing SRC-1/-2 double-deficient embryos, indicating that a fetal-specific defect delayed labor. SP-A, as well as the enzyme lysophosphatidylcholine acyltransferase-1 (LPCAT1), required for synthesis of surfactant dipalmitoylphosphatidylcholine, and the proinflammatory glycerophospholipid platelet-activating factor (PAF) were markedly reduced in SRC-1/-2–deficient fetal lungs near term. Injection of PAF or SP-A into AF at 17.5 days post coitum enhanced uterine NF-κB activation and contractile gene expression, promoted luteolysis, and rescued delayed parturition in SRC-1/-2–deficient embryo-bearing dams. These findings reveal that fetal lungs produce signals to initiate labor when mature and that SRC-1/-2–dependent production of SP-A and PAF is crucial for this process. PMID:26098214

  17. Steroid receptor coactivators 1 and 2 mediate fetal-to-maternal signaling that initiates parturition.

    PubMed

    Gao, Lu; Rabbitt, Elizabeth H; Condon, Jennifer C; Renthal, Nora E; Johnston, John M; Mitsche, Matthew A; Chambon, Pierre; Xu, Jianming; O'Malley, Bert W; Mendelson, Carole R

    2015-07-01

    The precise mechanisms that lead to parturition are incompletely defined. Surfactant protein-A (SP-A), which is secreted by fetal lungs into amniotic fluid (AF) near term, likely provides a signal for parturition; however, SP-A-deficient mice have only a relatively modest delay (~12 hours) in parturition, suggesting additional factors. Here, we evaluated the contribution of steroid receptor coactivators 1 and 2 (SRC-1 and SRC-2), which upregulate SP-A transcription, to the parturition process. As mice lacking both SRC-1 and SRC-2 die at birth due to respiratory distress, we crossed double-heterozygous males and females. Parturition was severely delayed (~38 hours) in heterozygous dams harboring SRC-1/-2-deficient embryos. These mothers exhibited decreased myometrial NF-κB activation, PGF2α, and expression of contraction-associated genes; impaired luteolysis; and elevated circulating progesterone. These manifestations also occurred in WT females bearing SRC-1/-2 double-deficient embryos, indicating that a fetal-specific defect delayed labor. SP-A, as well as the enzyme lysophosphatidylcholine acyltransferase-1 (LPCAT1), required for synthesis of surfactant dipalmitoylphosphatidylcholine, and the proinflammatory glycerophospholipid platelet-activating factor (PAF) were markedly reduced in SRC-1/-2-deficient fetal lungs near term. Injection of PAF or SP-A into AF at 17.5 days post coitum enhanced uterine NF-κB activation and contractile gene expression, promoted luteolysis, and rescued delayed parturition in SRC-1/-2-deficient embryo-bearing dams. These findings reveal that fetal lungs produce signals to initiate labor when mature and that SRC-1/-2-dependent production of SP-A and PAF is crucial for this process.

  18. Control of Amino Acid Homeostasis by a Ubiquitin Ligase-Coactivator Protein Complex.

    PubMed

    Guerra, Damian; Chapiro, Sonia M; Pratelli, Réjane; Yu, Shi; Jia, Weitao; Leary, Julie; Pilot, Guillaume; Callis, Judy

    2017-03-03

    Intercellular amino acid transport is essential for the growth of all multicellular organisms, and its dysregulation is implicated in developmental disorders. By an unknown mechanism, amino acid efflux is stimulated in plants by overexpression of a membrane-localized protein (GLUTAMINE DUMPER 1 (GDU1)) that requires a ubiquitin ligase (LOSS OF GDU 2 (LOG2). Here we further explore the physiological consequences of the interaction between these two proteins. LOG2 ubiquitin ligase activity is necessary for GDU1-dependent tolerance to exogenous amino acids, and LOG2 self-ubiquitination was markedly stimulated by the GDU1 cytosolic domain, suggesting that GDU1 functions as an adaptor or coactivator of amino acid exporter(s). However, other consequences more typical of a ligase-substrate relationship are observed: disruption of the LOG2 gene increased the in vivo half-life of GDU1, mass spectrometry confirmed that LOG2 ubiquitinates GDU1 at cytosolic lysines, and GDU1 protein levels decreased upon co-expression with active, but not enzymatically inactive LOG2. Altogether these data indicate LOG2 negatively regulates GDU1 protein accumulation by a mechanism dependent upon cytosolic GDU1 lysines. Although GDU1-lysine substituted protein exhibited diminished in vivo ubiquitination, overexpression of GDU1 lysine mutants still conferred amino acid tolerance in a LOG2-dependent manner, consistent with GDU1 being both a substrate and facilitator of LOG2 function. From these data, we offer a model in which GDU1 activates LOG2 to stimulate amino acid export, a process that could be negatively regulated by GDU1 ubiquitination and LOG2 self-ubiquitination.

  19. NMDA receptor-mediated excitotoxicity depends on the coactivation of synaptic and extrasynaptic receptors.

    PubMed

    Zhou, X; Hollern, D; Liao, J; Andrechek, E; Wang, H

    2013-03-28

    N-methyl-D-aspartate receptors (NMDAR) overactivation is linked to neurodegeneration. The current prevailing theory suggests that synaptic and extrasynaptic NMDAR (syn- and ex-NMDAR) impose counteracting effects on cell fate, and neuronal cell death is mainly mediated by the activation of ex-NMDAR. However, several lines of evidence implicate the limitation of this theory. Here, we demonstrate that activation of NMDAR bi-directionally regulated cell fate through stimulating pro-survival or pro-death signaling. While low-dose NMDA preferentially activated syn-NMDAR and stimulated the extracellular signal-regulated kinase ½-cAMP responsive element-binding protein-brain-derived neurotrophic factor pro-survival signaling, higher doses progressively activated increasing amount of ex-NMDAR along with syn-NMDAR and triggered cell death program. Interestingly, the activation of syn- or ex-NMDAR alone did not cause measurable cell death. Consistently, activation of syn- or ex-NMDAR alone stimulated pro-survival but not pro-death signaling. Next, we found that memantine, which was previously identified as an ex-NMDAR blocker, inhibited intracellular signaling mediated by syn- or ex-NMDAR. Simultaneous blockade of syn- and ex-NMDAR by memantine dose-dependently attenuated NMDAR-mediated death. Moreover, long- but not short-term treatment with high-dose NMDA or oxygen-glucose deprivation triggered cell death and suppressed pro-survival signaling. These data implicate that activation of syn- or ex-NMDAR alone is not neurotoxic. The degree of excitotoxicity depends on the magnitude and duration of syn- and ex-NMDAR coactivation. Finally, genome-wide examination demonstrated that the activation of syn- and ex-NMDAR lead to significant overlapping rather than counteracting transcriptional responses.

  20. Crx activates opsin transcription by recruiting HAT-containing co-activators and promoting histone acetylation

    PubMed Central

    Peng, Guang-Hua; Chen, Shiming

    2008-01-01

    The homeodomain transcription factor Crx is required for expression of many photoreceptor genes in the mammalian retina. The mechanism by which Crx activates transcription remains to be determined. Using protein–protein interaction assays, Crx was found to interact with three co-activator proteins (complexes): STAGA, Cbp and p300, all of which possess histone acetyl-transferase (HAT) activity. To determine the role of Crx–HAT interactions in target gene chromatin modification and transcriptional activation, quantitative RT–PCR and chromatin immunoprecipitation were performed on Crx target genes, rod and cone opsins, in developing mouse retina. Although cone opsins are transcribed earlier than rhodopsin during development, the transcription of each gene is preceded by the same sequence of events in their promoter and enhancer regions: (i) binding of Crx, followed by (ii) binding of HATs, (iii) the acetylation of histone H3, then (iv) binding of other photoreceptor transcription factors (Nrl and Nr2e3) and RNA polymerase II. In Crx knockout mice (Crx−/−), the association of HATs and AcH3 with target promoter/enhancer regions was significantly decreased, which correlates with aberrant opsin transcription and photoreceptor dysfunction in these mice. Similar changes to the opsin chromatin were seen in Y79 retinoblastoma cells, where opsin genes are barely transcribed. These defects in Y79 cells can be reversed by expressing a recombinant Crx or applying histone deacetylase inhibitors. Altogether, these results suggest that one mechanism for Crx-mediated transcriptional activation is to recruit HATs to photoreceptor gene chromatin for histone acetylation, thereby inducing and maintaining appropriate chromatin configurations for transcription. PMID:17656371

  1. Expression and characterization of the ferritin binding domain of Nuclear Receptor Coactivator-4 (NCOA4).

    PubMed

    Gryzik, Magdalena; Srivastava, Ayush; Longhi, Giovanna; Bertuzzi, Michela; Gianoncelli, Alessandra; Carmona, Fernando; Poli, Maura; Arosio, Paolo

    2017-11-01

    Ferritinophagy is the process of autophagic degradation of ferritin that participates in the regulation of cellular iron homeostasis. This process was shown to be mediated by the selective cargo-receptor Nuclear Receptor Coactivator-4 (NCOA4) that binds ferritin and targets it to emerging autophagosome. To characterize some of the biochemical properties of the interaction between the two proteins we cloned and expressed in E. coli the ferritin-binding domain of human NCOA4, fragment 383-522. It was purified and subjected to biochemical analysis. The NCOA4(383-522) fragment was expressed in soluble and dimeric form, and CD spectra indicated low level of secondary structure. The Ferritin binding activity of the fragment was investigated by developing an electrophoretic mobility shift and an ELISA assays. They showed that the NCOA4 fragment binds the H-ferritin with an affinity in the nM range, but not the R23A H-ferritin mutant and the L-ferritin chain, confirming the high specificity for the H-chain. The H-ferritin could bind up to 24 NCOA4(383-522) fragments forming highly stable and insoluble complexes. The binding was partially inhibited only by Fe(II) among the various divalent metal ions analyzed. The iron-dependent, highly-specific formation of the remarkably stable H-ferritin-NCOA4 complex shown in this work may be important for the characterization of the mechanism of ferritinophagy. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Playing tricks to ions

    NASA Astrophysics Data System (ADS)

    Leibfried, Dietrich

    2017-01-01

    Ted Hänsch's career is defined by breaking new ground in experimental physics. Curiosity, vivid imagination, deep understanding, patience and tenacity are part of the winning formula, but perhaps an equally important ingredient may be Ted's favorite past-time of exploring new tricks in his "Spiellabor" (play-lab), that often resurfaced as key ingredients in rather serious experiments later. On the occasion of Ted's 75th birthday, a few past and potential future experiments with trapped ions are playfully surveyed here. Some of these tricks are already part of the trade, some are currently emerging and a few are mostly speculation today. Maybe some of the latter will be realized and even prove useful in the future.

  3. Play in Practice: Case Studies in Young Children's Play.

    ERIC Educational Resources Information Center

    Brown, Cheryl Render, Ed.; Marchant, Catherine, Ed.

    This book uses a collection of stories, or "cases," as a basis for reflection, discussion, and learning about the many roles "play" has in children's lives. Each of the 12 cases addresses an issue of play from one of three categories--the role of adults in play, the cultural meanings of play, and the issues related to play in…

  4. Play in Practice: Case Studies in Young Children's Play.

    ERIC Educational Resources Information Center

    Brown, Cheryl Render, Ed.; Marchant, Catherine, Ed.

    This book uses a collection of stories, or "cases," as a basis for reflection, discussion, and learning about the many roles "play" has in children's lives. Each of the 12 cases addresses an issue of play from one of three categories--the role of adults in play, the cultural meanings of play, and the issues related to play in…

  5. A Distinct Mechanism for Coactivator versus Corepressor Function by Histone Methyltransferase G9a in Transcriptional Regulation*

    PubMed Central

    Purcell, Daniel J.; Jeong, Kwang Won; Bittencourt, Danielle; Gerke, Daniel S.; Stallcup, Michael R.

    2011-01-01

    Histone methyltransferase G9a has been understood primarily as a corepressor of gene expression, but we showed previously that G9a positively regulates nuclear receptor-mediated transcription in reporter gene assays. Here, we show that endogenous G9a contributes to the estradiol (E2)-dependent induction of some endogenous target genes of estrogen receptor (ER)α in MCF-7 breast cancer cells while simultaneously limiting the E2-induced expression of other ERα target genes. Thus, G9a has a dual and selective role as a coregulator for ERα target genes. The ERα binding regions associated with the pS2 gene, which requires G9a for E2-induced expression, are transiently occupied by G9a at 15 min after beginning E2 treatment, suggesting that G9a coactivator function is by direct interaction with ERα target genes. Transient reporter gene assays with deletion mutants of G9a demonstrated that domains previously associated with the corepressor functions of G9a (C-terminal methyltransferase domain, ankyrin repeat domain, and cysteine-rich domain) were unnecessary for G9a coactivator function in ERα-mediated transcription. In contrast, the N-terminal domain of G9a was necessary and sufficient for enhancement of ERα-mediated transcription and for E2-induced occupancy of G9a on ERα binding sites associated with endogenous target genes of ERα. In addition to a previously identified activation domain, this region contains a previously uncharacterized ligand-dependent ERα binding function, indicating how G9a is recruited to the target genes. Therefore, the coactivator and corepressor functions of G9a involve different G9a domains and different molecular mechanisms. PMID:21984853

  6. Nuclear receptor coactivators function in estrogen receptor- and progestin receptor-dependent aspects of sexual behavior in female rats.

    PubMed

    Molenda-Figueira, Heather A; Williams, Casey A; Griffin, Andreana L; Rutledge, Eric M; Blaustein, Jeffrey D; Tetel, Marc J

    2006-09-01

    The ovarian hormones, estradiol (E) and progesterone (P) facilitate the expression of sexual behavior in female rats. E and P mediate many of these behavioral effects by binding to their respective intracellular receptors in specific brain regions. Nuclear receptor coactivators, including Steroid Receptor Coactivator-1 (SRC-1) and CREB Binding Protein (CBP), dramatically enhance ligand-dependent steroid receptor transcriptional activity in vitro. Previously, our lab has shown that SRC-1 and CBP modulate estrogen receptor (ER)-mediated induction of progestin receptor (PR) gene expression in the ventromedial nucleus of the hypothalamus (VMN) and hormone-dependent sexual receptivity in female rats. Female sexual behaviors can be activated by high doses of E alone in ovariectomized rats, and thus are believed to be ER-dependent. However, the full repertoire of female sexual behavior, in particular, proceptive behaviors such as hopping, darting and ear wiggling, are considered to be PR-dependent. In the present experiments, the function of SRC-1 and CBP in distinct ER- (Exp. 1) and PR- (Exp. 2) dependent aspects of female sexual behavior was investigated. In Exp. 1, infusion of antisense oligodeoxynucleotides to SRC-1 and CBP mRNA into the VMN decreased lordosis intensity in rats treated with E alone, suggesting that these coactivators modulate ER-mediated female sexual behavior. In Exp. 2, antisense to SRC-1 and CBP mRNA around the time of P administration reduced PR-dependent ear wiggling and hopping and darting. Taken together, these data suggest that SRC-1 and CBP modulate ER and PR action in brain and influence distinct aspects of hormone-dependent sexual behaviors. These findings support our previous studies and provide further evidence that SRC-1 and CBP function together to regulate ovarian hormone action in behaviorally-relevant brain regions.

  7. Runx1 Regulation of Pu.1 Corepressor/Coactivator Exchange Identifies Specific Molecular Targets for Leukemia Differentiation Therapy*

    PubMed Central

    Gu, Xiaorong; Hu, Zhenbo; Ebrahem, Quteba; Crabb, John S.; Mahfouz, Reda Z.; Radivoyevitch, Tomas; Crabb, John W.; Saunthararajah, Yogen

    2014-01-01

    Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy. PMID:24695740

  8. Peroxisome Proliferator-activated Receptor γ Coactivator-1 α Isoforms Selectively Regulate Multiple Splicing Events on Target Genes.

    PubMed

    Martínez-Redondo, Vicente; Jannig, Paulo R; Correia, Jorge C; Ferreira, Duarte M S; Cervenka, Igor; Lindvall, Jessica M; Sinha, Indranil; Izadi, Manizheh; Pettersson-Klein, Amanda T; Agudelo, Leandro Z; Gimenez-Cassina, Alfredo; Brum, Patricia C; Dahlman-Wright, Karin; Ruas, Jorge L

    2016-07-15

    Endurance and resistance exercise training induces specific and profound changes in the skeletal muscle transcriptome. Peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α) coactivators are not only among the genes differentially induced by distinct training methods, but they also participate in the ensuing signaling cascades that allow skeletal muscle to adapt to each type of exercise. Although endurance training preferentially induces PGC-1α1 expression, resistance exercise activates the expression of PGC-1α2, -α3, and -α4. These three alternative PGC-1α isoforms lack the arginine/serine-rich (RS) and RNA recognition motifs characteristic of PGC-1α1. Discrete functions for PGC-1α1 and -α4 have been described, but the biological role of PGC-1α2 and -α3 remains elusive. Here we show that different PGC-1α variants can affect target gene splicing through diverse mechanisms, including alternative promoter usage. By analyzing the exon structure of the target transcripts for each PGC-1α isoform, we were able to identify a large number of previously unknown PGC-1α2 and -α3 target genes and pathways in skeletal muscle. In particular, PGC-1α2 seems to mediate a decrease in the levels of cholesterol synthesis genes. Our results suggest that the conservation of the N-terminal activation and repression domains (and not the RS/RNA recognition motif) is what determines the gene programs and splicing options modulated by each PGC-1α isoform. By using skeletal muscle-specific transgenic mice for PGC-1α1 and -α4, we could validate, in vivo, splicing events observed in in vitro studies. These results show that alternative PGC-1α variants can affect target gene expression both quantitatively and qualitatively and identify novel biological pathways under the control of this system of coactivators. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Computational stability of human knee joint at early stance in Gait: Effects of muscle coactivity and anterior cruciate ligament deficiency.

    PubMed

    Sharifi, M; Shirazi-Adl, A; Marouane, H

    2017-08-20

    As one of the most complex and vulnerable structures of body, the human knee joint should maintain dynamic equilibrium and stability in occupational and recreational activities. The evaluation of its stability and factors affecting it is vital in performance evaluation/enhancement, injury prevention and treatment managements. Knee stability often manifests itself by pain, hypermobility and giving-way sensations and is usually assessed by the passive joint laxity tests. Mechanical stability of both the human knee joint and the lower extremity at early stance periods of gait (0% and 5%) were quantified here for the first time using a hybrid musculoskeletal model of the lower extremity. The roles of muscle coactivity, simulated by setting minimum muscle activation at 0-10% levels and ACL deficiency, simulated by reducing ACL resistance by up to 85%, on the stability margin as well as joint biomechanics (contact/muscle/ligament forces) were investigated. Dynamic stability was analyzed using both linear buckling and perturbation approaches at the final deformed configurations in gait. The knee joint was much more stable at 0% stance than at 5% due to smaller ground reaction and contact forces. Muscle coactivity, when at lower intensities (<3% of its maximum active force), increased dynamic stability margin. Greater minimum activation levels, however, acted asan ineffective strategy to enhance stability. Coactivation also substantially increased muscle forces, joint loads and ACL force and hence the risk of further injury and degeneration. A deficiency in ACL decreases total ACL force (by 31% at 85% reduced stiffness) and the stability margin of the knee joint at the heel strike. It also markedly diminishes forces in lateral hamstrings (by up to 39%) and contact forces on the lateral plateau (by up to 17%). Current work emphasizes the need for quantification of the lower extremity stability margin in gait. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Modeling violations of the race model inequality in bimodal paradigms: co-activation from decision and non-decision components

    PubMed Central

    Zehetleitner, Michael; Ratko-Dehnert, Emil; Müller, Hermann J.

    2015-01-01

    The redundant-signals paradigm (RSP) is designed to investigate response behavior in perceptual tasks in which response-relevant targets are defined by either one or two features, or modalities. The common finding is that responses are speeded for redundantly compared to singly defined targets. This redundant-signals effect (RSE) can be accounted for by race models if the response times do not violate the race model inequality (RMI). When there are violations of the RMI, race models are effectively excluded as a viable account of the RSE. The common alternative is provided by co-activation accounts, which assume that redundant target signals are integrated at some processing stage. However, “co-activation” has mostly been only indirectly inferred and the accounts have only rarely been explicitly modeled; if they were modeled, the RSE has typically been assumed to have a decisional locus. Yet, there are also indications in the literature that the RSE might originate, at least in part, at a non-decisional or motor stage. In the present study, using a distribution analysis of sequential-sampling models (ex-Wald and Ratcliff Diffusion model), the locus of the RSE was investigated for two bimodal (audio-visual) detection tasks that strongly violated the RMI, indicative of substantial co-activation. Three model variants assuming different loci of the RSE were fitted to the quantile reaction time proportions: a decision, a non-decision, and a combined variant both to vincentized group as well as individual data. The results suggest that for the two bimodal detection tasks, co-activation has a shared decisional and non-decisional locus. These findings point to the possibility that the mechanisms underlying the RSE depend on the specifics (task, stimulus, conditions, etc.) of the experimental paradigm. PMID:25805987

  11. Transcriptional Regulation in Saccharomyces cerevisiae: Transcription Factor Regulation and Function, Mechanisms of Initiation, and Roles of Activators and Coactivators

    PubMed Central

    Hahn, Steven; Young, Elton T.

    2011-01-01

    Here we review recent advances in understanding the regulation of mRNA synthesis in Saccharomyces cerevisiae. Many fundamental gene regulatory mechanisms have been conserved in all eukaryotes, and budding yeast has been at the forefront in the discovery and dissection of these conserved mechanisms. Topics covered include upstream activation sequence and promoter structure, transcription factor classification, and examples of regulated transcription factor activity. We also examine advances in understanding the RNA polymerase II transcription machinery, conserved coactivator complexes, transcription activation domains, and the cooperation of these factors in gene regulatory mechanisms. PMID:22084422

  12. Preparation and spectroscopic properties of UO{sub 2}{sup 2+} - and Eu{sup 3+} -coactivated phosphate films

    SciTech Connect

    Syt`ko, V.V.; Aleshkevich, N.A.; Vasil`ev, S.R.; Umreiko, D.S.

    1995-05-01

    The present work is devoted to preparating UO{sub 2}{sup 2+} - and Eu{sup 3+}-coactivated films of alkali phosphates by ion-plasma evaporation and investigating their spectroscopic properties. Films were obtained on an IPU 6-5 setup using a two-electrode scheme. Luminescence spectra were recorded by Ramalog-4 and DSF-12 spectrophotometers. The kinetics of the luminescence was investigated with direct observation of the kinetic curves on the screen of an S8-13 oscillograph, recording by an FEU-84 photomulitplier, and excitation by a LGI-21 pulse nitrogen laser. The time resolution was no worse than 2%.

  13. Cervical Muscle Strength and Muscle Coactivation During Isometric Contractions in Patients With Migraine: A Cross-Sectional Study.

    PubMed

    Florencio, Lidiane Lima; de Oliveira, Anamaria Siriani; Carvalho, Gabriela Ferreira; Tolentino, Gabriella de Almeida; Dach, Fabiola; Bigal, Marcelo Eduardo; Fernández-de-las-Peñas, César; Bevilaqua Grossi, Débora

    2015-01-01

    This cross-sectional study investigated potential differences in cervical musculature in groups of migraine headaches vs. non-headache controls. Differences in cervical muscle strength and antagonist coactivation during maximal isometric voluntary contraction (MIVC) were analyzed between individuals with migraine and non-headache subjects and relationships between force with migraine and neck pain clinical aspects. A customized hand-held dynamometer was used to assess cervical flexion, extension, and bilateral lateral flexion strength in subjects with episodic migraine (n=31), chronic migraine (n = 21) and healthy controls (n = 31). Surface electromyography (EMG) from sternocleidomastoid, anterior scalene, and splenius capitis muscles were recorded during MIVC to evaluate antagonist coactivation. Comparison of main outcomes among groups was conducted with one-way analysis of covariance with the presence of neck pain as covariable. Correlations between peak force and clinical variables were demonstrated by Spearman's coefficient. Chronic migraine subjects exhibited lower cervical extension force (mean diff. from controls: 4.4 N/kg; mean diff from episodic migraine: 3.7 N/kg; P = .006) and spent significantly more time to generate peak force during cervical flexion (mean diff. from controls: 0.5 seconds; P = .025) and left lateral-flexion (mean diff. from controls: 0.4 seconds; mean diff. from episodic migraine: 0.5 seconds; P = .007). Both migraine groups showed significantly higher antagonist muscle coactivity of the splenius capitis muscle (mean diff. from controls: 20%MIVC, P = .03) during cervical flexion relative to healthy controls. Cervical extension peak force was moderately associated with the migraine frequency (rs: -0.30, P = .034), neck pain frequency (rs: -0.26, P = .020), and neck pain intensity (rs: -0.27, P = .012). Patients with chronic migraine exhibit altered muscle performance, took longer to reach peak of

  14. Synergistic Co-activation Increases the Extent of Mechanical Interaction between Rat Ankle Plantar-Flexors

    PubMed Central

    Tijs, Chris; van Dieën, Jaap H.; Baan, Guus C.; Maas, Huub

    2016-01-01

    Force transmission between rat ankle plantar-flexors has been found for physiological muscle lengths and relative positions, but only with all muscles maximally activated. The aims of this study were to assess intermuscular mechanical interactions between ankle plantar-flexors during (i) fully passive conditions, (ii) excitation of soleus (SO), (iii) excitation of lateral gastrocnemius (LG), and (iv) during co-activation of SO, and LG (SO&LG). We assessed effects of proximal lengthening of LG and plantaris (PL) muscles (i.e., simulating knee extension) on forces exerted at the distal SO tendon (FSO) and on the force difference between the proximal and distal LG+PL tendons (ΔFLG+PL) of the rat. LG+PL lengthening increased FSO to a larger extent (p = 0.017) during LG excitation (0.0026 N/mm) than during fully passive conditions (0.0009 N/mm). Changes in FSO in response to LG+PL lengthening were lower (p = 0.002) during SO only excitation (0.0056 N/mm) than during SO&LG excitation (0.0101 N/mm). LG+PL lengthening changed ΔFLG+PL to a larger extent (p = 0.007) during SO excitation (0.0211 N/mm) than during fully passive conditions (0.0157 N/mm). In contrast, changes in ΔFLG+PL in response to LG+PL lengthening during LG excitation (0.0331 N/mm) were similar (p = 0.161) to that during SO&LG excitation (0.0370 N/mm). In all conditions, changes of FSO were lower than those of ΔFLG+PL. This indicates that muscle forces were transmitted not only between LG+PL and SO, but also between LG+PL and other surrounding structures. In addition, epimuscular myofascial force transmission between rat ankle plantar-flexors was enhanced by muscle activation. However, the magnitude of this interaction was limited. PMID:27708589

  15. Farm Hall: The Play

    NASA Astrophysics Data System (ADS)

    Cassidy, David C.

    2013-03-01

    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  16. Impaired coactivator activity of the Gly{sub 482} variant of peroxisome proliferator-activated receptor {gamma} coactivator-1{alpha} (PGC-1{alpha}) on mitochondrial transcription factor A (Tfam) promoter

    SciTech Connect

    Choi, Yon-Sik; Hong, Jung-Man; Lim, Sunny; Ko, Kyung Soo; Pak, Youngmi Kim . E-mail: ymkimpak@amc.seoul.kr

    2006-06-09

    Mitochondrial dysfunction may cause diabetes or insulin resistance. Peroxisome proliferation-activated receptor-{gamma} (PPAR-{gamma}) coactivator-1 {alpha} (PGC-1{alpha}) increases mitochondrial transcription factor A (Tfam) resulting in mitochondrial DNA content increase. An association between a single nucleotide polymorphism (SNP), G1444A(Gly482Ser), of PGC-1{alpha} coding region and insulin resistance has been reported in some ethnic groups. In this study, we investigated whether a change of glycine to serine at codon 482 of PGC-1{alpha} affected the Tfam promoter activity. The cDNA of PGC-1{alpha} variant bearing either glycine or serine at 482 codon was transfected into Chang human hepatocyte cells. The PGC-1{alpha} protein bearing glycine had impaired coactivator activity on Tfam promoter-mediated luciferase. We analyzed the PGC-1{alpha} genotype G1444A and mitochondrial DNA (mtDNA) copy number from 229 Korean leukocyte genomic DNAs. Subjects with Gly/Gly had a 20% lower amount of peripheral blood mtDNA than did subjects with Gly/Ser and Ser/Ser (p < 0.05). No correlation was observed between diabetic parameters and PGC-1{alpha} genotypes in Koreans. These results suggest that PGC-1{alpha} variants with Gly/Gly at 482nd amino acid may impair the Tfam transcription, a regulatory function of mitochondrial biogenesis, resulting in dysfunctional mtDNA replication.

  17. Epigenetic regulation of insulin resistance in nonalcoholic fatty liver disease: impact of liver methylation of the peroxisome proliferator-activated receptor γ coactivator 1α promoter.

    PubMed

    Sookoian, Silvia; Rosselli, Maria Soledad; Gemma, Carolina; Burgueño, Adriana L; Fernández Gianotti, Tomas; Castaño, Gustavo O; Pirola, Carlos J

    2010-12-01

    Insulin resistance (IR) and mitochondrial dysfunction play a central role in the pathophysiology of nonalcoholic fatty liver disease (NAFLD). We hypothesized that genetic factors and epigenetic modifications occurring in the liver contribute to the IR phenotype. We specifically examined whether fatty liver and IR are modified by hepatic DNA methylation of the peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A) and mitochondrial transcription factor A (TFAM) promoters, and also evaluated whether liver mitochondrial DNA (mtDNA) content is associated with NAFLD and IR. We studied liver biopsies obtained from NAFLD patients in a case-control design. After bisulfite treatment of DNA, we used methylation-specific polymerase chain reaction (PCR) to assess the putative methylation of three CpG in the PPARGC1A and TFAM promoters. Liver mtDNA quantification using nuclear DNA (nDNA) as a reference was evaluated by way of real-time PCR. Liver PPARGC1A methylated DNA/unmethylated DNA ratio correlated with plasma fasting insulin levels and homeostasis model assessment of insulin resistance (HOMA-IR); TFAM methylated DNA/unmethylated DNA ratio was inversely correlated with insulin levels. PPARGC1A promoter methylation was inversely correlated with the abundance of liver PPARGC1A messenger RNA. The liver mtDNA/nDNA ratio was significantly higher in control livers compared with NAFLD livers. mtDNA/nDNA ratio was inversely correlated with HOMA-IR, fasting glucose, and insulin and was inversely correlated with PPARGC1A promoter methylation. Our data suggest that the IR phenotype and the liver transcriptional activity of PPARGC1A show a tight interaction, probably through epigenetic modifications. Decreased liver mtDNA content concomitantly contributes to peripheral IR. Copyright © 2010 American Association for the Study of Liver Diseases.

  18. A preliminary investigation of the role of the transcription co-activators YAP/TAZ of the Hippo signalling pathway in canine and feline mammary tumours.

    PubMed

    Beffagna, G; Sacchetto, R; Cavicchioli, L; Sammarco, A; Mainenti, M; Ferro, S; Trez, D; Zulpo, M; Michieletto, S; Cecchinato, A; Goldschmidt, M; Zappulli, V

    2016-01-01

    Breast cancer is the most common cancer in women worldwide. Cancer metastases are responsible for the high mortality rate. A small but distinct subset of cells, cancer stem cells (CSCs), have the capacity to self-renew, initiate tumour formation, and develop metastases. The CSC content in human breast cancer correlates with the Hippo tumour suppressor signalling pathway. Specifically, the activity of YAP/TAZ, transcription co-activators of the Hippo pathway, sustains the self-renewal and tumour-initiation capacities of CSCs. Little is known about YAP/TAZ in canine and feline mammary tumours, which are very common tumours. The preliminary aim of the study was to investigate the expression of YAP/TAZ in canine and feline mammary tumours by Western blot and immunohistochemistry. Increased cytoplasmic and nuclear expression of YAP/TAZ was observed in all carcinomas compared to normal tissues, indicating neoplastic deregulation of the Hippo pathway. Nuclear expression significantly increased in grade III (high grade carcinomas) compared to grade I (low grade carcinomas) tumours, suggesting that YAP/TAZ play a role in the increased aggressiveness of these tumours. Moreover, different scoring systems for immunohistochemical analyses were compared and the H index and the Allred scores were the most significant. In conclusion, YAP/TAZ are expressed in aggressive canine and feline mammary tumours as reported in some human cancers. Further studies might better elucidate the role of the Hippo pathway in prognosis and as a target for new therapies. In addition, tumours in dogs and cats may be a useful model to study this pathway. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Large tumor suppressor homologs 1 and 2 regulate mouse liver progenitor cell proliferation and maturation through antagonism of the coactivators YAP and TAZ.

    PubMed

    Yi, Jing; Lu, Li; Yanger, Kilangsungla; Wang, Wenqi; Sohn, Bo Hwa; Stanger, Ben Z; Zhang, Min; Martin, James F; Ajani, Jaffer A; Chen, Junjie; Lee, Ju-Seog; Song, Shumei; Johnson, Randy L

    2016-11-01

    In the adult liver, the Hippo pathway mammalian STE20-like protein kinases 1 and 2 and large tumor suppressor homologs 1 and 2 (LATS1/2) control activation of the transcriptional coactivators Yes-associated protein (YAP) and WW domain containing transcription regulator 1 (TAZ) in hepatocytes and biliary epithelial cells, thereby regulating liver cell proliferation, differentiation, and malignant transformation. Less is known about the contribution of Hippo signaling to liver development. We used conditional mutagenesis to show that the Hippo signaling pathway kinases LATS1 and LATS2 are redundantly required during mouse liver development to repress YAP and TAZ in both the biliary epithelial and hepatocyte lineages. In the absence of LATS1/2, biliary epithelial cells exhibit excess proliferation while hepatoblasts fail to mature into hepatocytes, defects that result in perinatal lethality. Using an in vitro hepatocyte differentiation assay, we demonstrate that YAP activity decreases and Hippo pathway kinase activities increase upon differentiation. In addition, we show that YAP activation in vitro, resulting from either depletion of its negative regulators LATS1/2 or expression of a mutant form of YAP that is less efficiently phosphorylated by LATS1/2, results in transcriptional suppression of genes that normally accompany hepatocyte maturation. Moreover, we provide evidence that YAP activity is repressed by Hippo pathway activation upon hepatocytic maturation in vitro. Finally, we examine the localization of YAP during fetal liver development and show that higher levels of YAP are found in biliary epithelial cells, while in hepatocytes YAP levels decrease with hepatocyte maturation. Hippo signaling, mediated by the LATS1 and LATS2 kinases, is required to restrict YAP and TAZ activation during both biliary and hepatocyte differentiation. These findings suggest that dynamic regulation of the Hippo signaling pathway plays an important role in differentiation and

  20. Renal Proximal Tubule Na,K-ATPase is Controlled by CREB Regulated Transcriptional CoActivators as well as Salt Inducible Kinase 1

    PubMed Central

    Taub, Mary; Garamella, Sudha; Kim, Dongwook; Rajkhowa, Trivikram; Cutuli, Facundo

    2015-01-01

    Sodium reabsorption by the kidney is regulated by locally produced natriuretic and anti-natriuretic factors, including dopamine and norepinephrine, respectively. Previous studies indicated that signaling events initiated by these natriuretic and anti-natriuretic factors achieve their effects by altering the phosphorylation of Na,K-ATPase in the renal proximal tubule, and that Protein Kinase A (PKA) and Calcium mediated signaling pathways are involved. The same signaling pathways also control the transcription of the Na,K-ATPase β subunit gene atp1b1 in renal proximal tubule cells. In this report, evidence is presented that 1) both the recently discovered cAMP-Regulated Transcriptional Coactivators (CRTCs), and Salt Inducible Kinase 1 (SIK1) contribute to the transcriptional regulation of atp1b1 in renal proximal tubule (RPT) cells, and 2) that renal effectors including norepinephrine, dopamine, prostaglandins and sodium play a role. Exogenously expressed CRTCs stimulate atp1b1 transcription. Evidence for a role of endogenous CRTCs includes the loss of transcriptional regulation of atp1b1 by a dominant negative CRTC, as well as by a CREB mutant, with an altered CRTC binding site. In a number of experimental systems, SIK phosphorylates CRTCs, which are then sequestered in the cytoplasm, preventing their nuclear effects. Consistent with such a role of SIK in primary RPT cells, atp1b1 transcription increased in the presence of a dominant negative SIK1, and in addition, regulation by dopamine, norepinephrine and monensin was disrupted by a dominant negative SIK1. These latter observations can be explained, if SIK1 is phosphorylated and inactivated in the presence of these renal effectors. Our results support the hypothesis that Na,K-ATPase in the renal proximal tubule is regulated at the transcriptional level via SIK1 and CRTCs by renal effectors, in addition to the previously reported control of the phosphorylation of Na,K-ATPase. PMID:26432356

  1. Down-regulation of bile acid synthesis and a metabolic co-activator under hypoxic conditions - implications in obstructive sleep apnea.

    PubMed

    Johnson, Paul R

    2008-10-01

    Obstructive sleep apnea is characterized by episodes of intermittent hypoxia that occur while the afflicted person sleeps, and is believed to affect and have a negative impact on many people worldwide. Both observational evidence in obstructive sleep apnea patients and direct studies in mice mimicking the disease strongly support an increased risk for atherosclerosis in these groups. Studies to date on atherosclerosis in obstructive sleep apnea have been focused on cholesterol synthesis. However, dysregulation of bile acid synthesis, which is an important means of cholesterol removal, has not been considered in any sleep disorder model to date. While the relationship between hypoxia and bile acid regulation has been explored in a variety of models, no unifying theory currently ties in the pathologic effect of intermittent hypoxia on bile acid regulation in humans or animals. The goal of this article is to propose the role intermittent hypoxia plays in disrupting bile acid synthesis in patients with obstructive sleep apnea, and its metabolic consequences. Reviewed and discussed are the complex interactions of several key molecular players known to be involved in metabolism with emphasis on the principle bile acid synthesis enzyme, cholesterol 7-alpha-hydroxylase, which is proposed to have reduced activity under hypoxic conditions. Furthermore, the metabolic consequences of reduced levels of active peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1alpha) under hypoxia, and hypothetically in obstructive sleep apnea, are explored. A better molecular understanding of bile acid synthesis and metabolic dysregulation in this context will hopefully promote the study of new targets in human sleep apneas, and encourage clinical trials using existing therapeutic and dietary interventions in patients afflicted with these conditions.

  2. SMAD3 Negatively Regulates Serum Irisin and Skeletal Muscle FNDC5 and Peroxisome Proliferator-activated Receptor γ Coactivator 1-α (PGC-1α) during Exercise*

    PubMed Central

    Tiano, Joseph P.; Springer, Danielle A.; Rane, Sushil G.

    2015-01-01

    Beige adipose cells are a distinct and inducible type of thermogenic fat cell that express the mitochondrial uncoupling protein-1 and thus represent a powerful target for treating obesity. Mice lacking the TGF-β effector protein SMAD3 are protected against diet-induced obesity because of browning of their white adipose tissue (WAT), leading to increased whole body energy expenditure. However, the role SMAD3 plays in WAT browning is not clearly understood. Irisin is an exercise-induced skeletal muscle hormone that induces WAT browning similar to that observed in SMAD3-deficient mice. Together, these observations suggested that SMAD3 may negatively regulate irisin production and/or secretion from skeletal muscle. To address this question, we used wild-type and SMAD3 knock-out (Smad3−/−) mice subjected to an exercise regime and C2C12 myotubes treated with TGF-β, a TGF-β receptor 1 pharmacological inhibitor, adenovirus expressing constitutively active SMAD3, or siRNA against SMAD3. We find that in Smad3−/− mice, exercise increases serum irisin and skeletal muscle FNDC5 (irisin precursor) and its upstream activator peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) to a greater extent than in wild-type mice. In C2C12 myotubes, TGF-β suppresses FNDC5 and PGC-1α mRNA and protein levels via SMAD3 and promotes SMAD3 binding to the FNDC5 and PGC-1α promoters. These data establish that SMAD3 suppresses FNDC5 and PGC-1α in skeletal muscle cells. These findings shed light on the poorly understood regulation of irisin/FNDC5 by demonstrating a novel association between irisin and SMAD3 signaling in skeletal muscle. PMID:25648888

  3. SMAD3 negatively regulates serum irisin and skeletal muscle FNDC5 and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) during exercise.

    PubMed

    Tiano, Joseph P; Springer, Danielle A; Rane, Sushil G

    2015-03-20

    Beige adipose cells are a distinct and inducible type of thermogenic fat cell that express the mitochondrial uncoupling protein-1 and thus represent a powerful target for treating obesity. Mice lacking the TGF-β effector protein SMAD3 are protected against diet-induced obesity because of browning of their white adipose tissue (WAT), leading to increased whole body energy expenditure. However, the role SMAD3 plays in WAT browning is not clearly understood. Irisin is an exercise-induced skeletal muscle hormone that induces WAT browning similar to that observed in SMAD3-deficient mice. Together, these observations suggested that SMAD3 may negatively regulate irisin production and/or secretion from skeletal muscle. To address this question, we used wild-type and SMAD3 knock-out (Smad3(-/-)) mice subjected to an exercise regime and C2C12 myotubes treated with TGF-β, a TGF-β receptor 1 pharmacological inhibitor, adenovirus expressing constitutively active SMAD3, or siRNA against SMAD3. We find that in Smad3(-/-) mice, exercise increases serum irisin and skeletal muscle FNDC5 (irisin precursor) and its upstream activator peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) to a greater extent than in wild-type mice. In C2C12 myotubes, TGF-β suppresses FNDC5 and PGC-1α mRNA and protein levels via SMAD3 and promotes SMAD3 binding to the FNDC5 and PGC-1α promoters. These data establish that SMAD3 suppresses FNDC5 and PGC-1α in skeletal muscle cells. These findings shed light on the poorly understood regulation of irisin/FNDC5 by demonstrating a novel association between irisin and SMAD3 signaling in skeletal muscle. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. [Study of peroxisome proliferator-activated receptor-γ coactivator-1α expression and cytoapoptosis in masseter muscles of unilateral chewing rat].

    PubMed

    Yang, Yingying; Ding, Tingting; Wu, Qingting; Kong, Jingjing; Qi, Dong; Ji, Ping

    2014-07-01

    To investigate the changes of peroxisome proliferator- activated receptor-γ coactivator -1α (PGC-1α) mRNA and cytoapoptosis in the rats' masseter muscle which had been influenced by unilateral chewing, and to explore the theoretical foundation of changes in masticatory muscles induced by unilateral chewing. The animal models were established by extracting the Wistar rats' left maxillary molars. Thirty- six female Wistar rats were randomly divided into four groups of 2, 4, 6 and 8 weeks, nine each. In each group there were six rats with molar extracted and three as control. The Ca²⁺ level was detected by atomic spectrophotometric method. The relative expression of PGC-1α mRNA was detected by real- time fluorescent quantitative PCR. The apoptosis index was detected by Hoechst staining. The Ca²⁺ level in the muscle on the extraction side were significantly higher than that in the controls in the beginning stage of unilateral chewing, and reached the peak at the 4th week [(43.62 ± 2.36) µg/g]. The relative expressions of PGC-1α increased from the beginning and reached the maximum level at the 4th week [extraction side: (1.57 ± 0.10); non-extraction side: (1.92 ± 0.06)], while the relative expressions of PGC-1α in 6 and 8 weeks decreased gradually [extraction side: (1.06 ± 0.08), (1.08 ± 0.07); non- extraction side: (1.09 ± 0.10), (1.11 ± 0.08)]. The changes of apoptosis index on non- extraction side increased continually and peaked at the 6th week [(38.56 ± 1.64)%]. PGC-1α and cytoapoptosis played important roles in different stages of tissue remodeling induced by unilateral chewing.

  5. Peroxisome proliferator-activated receptors (PPARs) and associated transcription factors in colon cancer: reduced expression of PPARgamma-coactivator 1 (PGC-1).

    PubMed

    Feilchenfeldt, Jonas; Bründler, Marie Anne; Soravia, Claudio; Tötsch, Martin; Meier, Christoph A

    2004-01-08

    Peroxisome proliferator-activated receptors (PPARs) alpha,beta/delta and gamma are fatty acid sensitive transcription factors that have been implicated in colorectal cancer. To better understand their role, we studied the expression levels of all PPAR-isoforms and transcriptional partners such as the retinoid X receptor alpha (RXRalpha) and PPARgamma-coactivator-1 (PGC-1) by means of real-time PCR in 17 patients with colon cancer. While a heterogeneous pattern was observed for the expression level of the PPAR-isoforms alpha,beta/delta and gamma, the coactivator PGC-1 was significantly decreased in 15 of 17 tumors. Taken together our data suggest that the transcriptional activity of PPARgamma may not only be decreased by mutation but also by downregulation of the coactivator PGC-1 of PPARgamma.

  6. Playing My Heart Out: Original Play as Adventure.

    ERIC Educational Resources Information Center

    Donaldson, O. Fred

    1999-01-01

    "Original" play denotes play that is pre-cultural--before conceptualizations and learned responses. Four anecdotes about play with an infant with Down's syndrome, a child with leukemia, a lioness, and a dying woman illustrate the connections between beings and between the ordinary and the sacred during trusting, fearless, playful encounters. (SV)

  7. Playing My Heart Out: Original Play as Adventure.

    ERIC Educational Resources Information Center

    Donaldson, O. Fred

    1999-01-01

    "Original" play denotes play that is pre-cultural--before conceptualizations and learned responses. Four anecdotes about play with an infant with Down's syndrome, a child with leukemia, a lioness, and a dying woman illustrate the connections between beings and between the ordinary and the sacred during trusting, fearless, playful encounters. (SV)

  8. Child's Play: Revisiting Play in Early Childhood Settings.

    ERIC Educational Resources Information Center

    Dau, Elizabeth, Ed.; Jones, Elizabeth, Ed.

    Noting that play is an essential aspect of learning for young children, this book presents a collection of articles on children's play in Australia. Part 1, "Play, Development, and Learning," contains the following chapters: (1) "The Role of Play in Development and Learning" (Ann Glover); (2) "Stop, Look, and Listen:…

  9. Imagination, Playfulness, and Creativity in Children's Play with Different Toys

    ERIC Educational Resources Information Center

    Mo????ller, Signe?? Juhl?

    2015-01-01

    Based on a four-month experimental study of preschool children's play with creative-construction and social-fantasy toys, the author examines the in?uence of both types of toys on the play of preschool children. Her comparative analysis considers the impact of transformative play on the development of imagination during play activities and…

  10. Child's Play: Revisiting Play in Early Childhood Settings.

    ERIC Educational Resources Information Center

    Dau, Elizabeth, Ed.; Jones, Elizabeth, Ed.

    Noting that play is an essential aspect of learning for young children, this book presents a collection of articles on children's play in Australia. Part 1, "Play, Development, and Learning," contains the following chapters: (1) "The Role of Play in Development and Learning" (Ann Glover); (2) "Stop, Look, and Listen:…

  11. Rifampicin-Independent Interactions between the Pregnane X Receptor Ligand Binding Domain and Peptide Fragments of Coactivator and Corepressor Proteins

    PubMed Central

    Navaratnarajah, Punya; Steele, Bridgett L.; Redinbo, Matthew R.; Thompson, Nancy L.

    2015-01-01

    The pregnane X receptor (PXR), a member of the nuclear receptor superfamily, regulates the expression of drug-metabolizing enzymes in a ligand-dependent manner. The conventional view of nuclear receptor action is that ligand binding enhances the receptor’s affinity for coactivator proteins, while decreasing its affinity for corepressors. To date, however, no known rigorous biophysical studies have been conducted to investigate the interaction among PXR, its coregulators, and ligands. In this work, steady-state total internal reflection fluorescence microscopy (TIRFM) and total internal reflection with fluorescence recovery after photobleaching were used to measure the thermodynamics and kinetics of the interaction between the PXR ligand binding domain and a peptide fragment of the steroid receptor coactivator-1 (SRC-1) in the presence and absence of the established PXR agonist, rifampicin. Equilibrium dissociation and dissociation rate constants of ~5 μM and ~2 s−1, respectively, were obtained in the presence and absence of rifampicin, indicating that the ligand does not enhance the affinity of the PXR and SRC-1 fragments. Additionally, TIRFM was used to examine the interaction between PXR and a peptide fragment of the corepressor protein, the silencing mediator for retinoid and thyroid receptors (SMRT). An equilibrium dissociation constant of ~70 μM was obtained for SMRT in the presence and absence of rifampicin. These results strongly suggest that the mechanism of ligand-dependent activation in PXR differs significantly from that seen in many other nuclear receptors. PMID:22185585

  12. Identification of mechanism that couples multisite phosphorylation of Yes-associated protein (YAP) with transcriptional coactivation and regulation of apoptosis.

    PubMed

    Lee, Kyung-Kwon; Yonehara, Shin

    2012-03-16

    The transcriptional coactivator Yes-associated protein (YAP) has been implicated in tumorigenesis by regulating cell proliferation and apoptosis. YAP interacts with the transcription factor TEAD and is essential in mediating TEAD-dependent gene expression. Here we show that YAP is hyperphosphorylated and activated in response to genotoxic stress such as UV irradiation and cisplatin treatment. Using high resolution mobility shift assay for phosphorylated proteins, we identified multiple sites of phosphorylation induced by UV irradiation. Pretreatment with p38 and JNK inhibitors completely suppressed the mobility retardation of phosphorylated YAP in UV-irradiated cells. Co-immunoprecipitation experiments showed that the physical interaction of YAP with TEAD was markedly enhanced by UV irradiation or CDDP treatment but suppressed by pretreatment with p38 and JNK inhibitors. Similarly, pretreatment with p38 and JNK inhibitors suppressed the expression of YAP/TEAD target genes, which were elevated on exposure to genotoxic stress. Using phosphomimetic and phosphorylation-deficient YAP mutants, we showed that the coactivator activity of YAP correlated with its state of phosphorylation and sensitivity to cisplatin-induced apoptosis. Our results demonstrate that multisite phosphorylation of YAP induces YAP/TEAD-dependent gene expression and provides a mechanism by which YAP regulates apoptosis differently depending on cellular context.

  13. Fast skeletal muscle troponin I is a co-activator of estrogen receptor-related receptor {alpha}

    SciTech Connect

    Li Yuping; Chen Bin; Chen Jian; Lou Guiyu; Chen Shiuan; Zhou Dujin

    2008-05-16

    ERR{alpha} (estrogen receptor-related receptor {alpha}) is a member of the nuclear receptor superfamily. To further our understanding of the detailed molecular mechanism of transcriptional regulation by ERR{alpha}, we searched for ERR{alpha}-interacting proteins using a yeast two-hybrid system by screening a human mammary gland cDNA expression library with the ligand-binding domain (LBD) of ERR{alpha} as the 'bait'. Fast skeletal muscle troponin I (TNNI2), along with several known nuclear receptor co-activators, were isolated. We demonstrated that TNNI2 localizes to the cell nucleus and interacts with ERR{alpha} in co-immunoprecipitation experiments. GST pull-down assays also revealed that TNNI2 interacts directly with ERR{alpha}. Through luciferase reporter gene assays, TNNI2 was found to enhance the transactivity of ERR{alpha}. Combining mutagenesis and yeast two-hybrid assays, we mapped the ERR{alpha}-interacting domain on TNNI2 to a region encompassing amino acids 1-128. These findings reveal a new function for TNNI2 as a co-activator of ERR{alpha}.

  14. Co-activation of NR2A and NR2B subunits induces resistance to fear extinction.

    PubMed

    Leaderbrand, Katherine; Corcoran, Kevin A; Radulovic, Jelena

    2014-09-01

    Unpredictable stress is known to profoundly enhance susceptibility to fear and anxiety while reducing the ability to extinguish fear when threat is no longer present. Accordingly, partial aversive reinforcement, via random exposure to footshocks, induces fear that is resistant to extinction. Here we sought to determine the hippocampal mechanisms underlying susceptibility versus resistance to context fear extinction as a result of continuous (CR) and partial (PR) reinforcement, respectively. We focused on N-methyl-D-aspartate receptor (NMDAR) subunits 2A and B (NR2A and NR2B) as well as their downstream signaling effector, extracellular signal-regulated kinase (ERK), based on their critical role in the acquisition and extinction of fear. Pharmacological inactivation of NR2A, but not NR2B, blocked extinction after CR, whereas inactivation of NR2A, NR2B, or both subunits facilitated extinction after PR. The latter finding suggests that co-activation of NR2A and NR2B contributes to persistent fear following PR. In contrast to CR, PR increased membrane levels of ERK and NR2 subunits after the conditioning and extinction sessions, respectively. In parallel, nuclear activation of ERK was significantly reduced after the extinction session. Thus, co-activation and increased surface expression of NR2A and NR2B, possibly mediated by ERK, may cause persistent fear. These findings suggest that patients with post-traumatic stress disorder (PTSD) may benefit from antagonism of specific NR2 subunits.

  15. Separate regions of glucocorticoid receptor, coactivator TIF2, and comodulator STAMP modify different parameters of glucocorticoid-mediated gene induction.

    PubMed Central

    Awasthi, Smita; Simons, S. Stoney

    2012-01-01

    Increased specificity in steroid-regulated gene expression is a long-sought goal of endocrinologists. Considerable progress has resulted from the discovery of coactivators, corepressors, and comodulators that adjust the total activity (Amax) of gene induction. Two less frequently quantitated, but equally potent, means of improving specificity are the concentration of agonist steroid required for half-maximal activity (EC50) and the residual or partial agonist activity displayed by most antisteroids (PAA). It is usually assumed that the modulatory activity of transcriptional cofactors coordinately regulates Amax, EC50, and PAA. Here we examine the hypothesis that these three parameters can be independently modified by separate protein domains. The test system involves three differently sized fragments of each of three factors (glucocorticoid receptor [GR], coactivator TIF2, and comodulator STAMP), which are shown to form a ternary complex and similarly affect the induction properties of transfected and endogenous genes. Twenty five different fragment combinations of the ternary complex are examined for their ability to modulate the Amax, EC50, and PAA of a transiently transfected synthetic reporter gene. Different combinations selectively alter one, two, or all three parameters. These results clearly demonstrate that Amax, EC50, and PAA can be independently regulated under some conditions by different pathways or molecular interactions. This new mechanistic insight suggests that selected activities of individual transcription factors are attractive targets for small molecules, which would have obvious clinical applications for increasing the specificity of steroids during endocrine therapies. PMID:22342989

  16. Steroid receptor coactivator-3 expression in lung cancer and its role in the regulation of cancer cell survival and proliferation.

    PubMed

    Cai, Di; Shames, David S; Raso, Maria Gabriela; Xie, Yang; Kim, Young H; Pollack, Jonathan R; Girard, Luc; Sullivan, James P; Gao, Boning; Peyton, Michael; Nanjundan, Meera; Byers, Lauren; Heymach, John; Mills, Gordon; Gazdar, Adi F; Wistuba, Ignacio; Kodadek, Thomas; Minna, John D

    2010-08-15

    Steroid receptor coactivator-3 (SRC-3) is a histone acetyltransferase and nuclear hormone receptor coactivator, located on 20q12, which is amplified in several epithelial cancers and well studied in breast cancer. However, its possible role in lung cancer pathogenesis is unknown. We found SRC-3 to be overexpressed in 27% of non-small cell lung cancer (NSCLC) patients (n = 311) by immunohistochemistry, which correlated with poor disease-free (P = 0.0015) and overall (P = 0.0008) survival. Twenty-seven percent of NSCLCs exhibited SRC-3 gene amplification, and we found that lung cancer cell lines expressed higher levels of SRC-3 than did immortalized human bronchial epithelial cells (HBEC), which in turn expressed higher levels of SRC-3 than did cultured primary human HBECs. Small interfering RNA-mediated downregulation of SRC-3 in high-expressing, but not in low-expressing, lung cancer cells significantly inhibited tumor cell growth and induced apoptosis. Finally, we found that SRC-3 expression is inversely correlated with gefitinib sensitivity and that SRC-3 knockdown results in epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancers becoming more sensitive to gefitinib. Taken together, these data suggest that SRC-3 may be an important oncogene and therapeutic target for lung cancer. (c)2010 AACR.

  17. Jab1 is a T2-dependent coactivator or a T3-dependent corepressor of TRB1-mediated gene regulation.

    PubMed

    Hernández-Puga, Gabriela; Mendoza, Arturo; León-Del-Río, Alfonso; Orozco, Aurea

    2017-03-01

    Thyroid hormones (THs) induce pleiotropic effects in vertebrates, mainly through the activation or repression of gene expression. These mechanisms involve thyroid hormone binding to thyroid hormone receptors, an event that is followed by the sequential recruitment of coactivator or corepressor proteins, which in turn modify the rate of transcription. In the present study, we looked for specific coregulators recruited by the long isoform of the teleostean thyroid hormone receptor beta 1 (L-Trb1) when bound to the bioactive TH, 3,5-T2 (T2). We found that jun activation domain-binding protein1 (Jab1) interacts with L-Trb1 + T2 complex. Using both the teleostean and human TRB1 isoforms, we characterized the Jab1-TRB1 by yeast two-hybrid, pull-down and transactivation assays. Our results showed that the TRB1-Jab1 interaction was ligand dependent and involved the single Jab1 nuclear receptor box, as well as the ligand-binding and N-terminal domains of TRB1. We also provide evidence of ligand-dependent, dual coregulatory properties of Jab1. Indeed, when T2 is bound to L-Trb1 or hTRB1, Jab1 acts as a coactivator of transcription, whereas it has corepressor activity when interacting with the T3-bound S-Trb1 or hTRB1. These mechanisms could explain some of the pleiotropic actions exerted by THs to regulate diverse biological processes.

  18. Pain as a reward: changing the meaning of pain from negative to positive co-activates opioid and cannabinoid systems.

    PubMed

    Benedetti, Fabrizio; Thoen, Wilma; Blanchard, Catherine; Vighetti, Sergio; Arduino, Claudia

    2013-03-01

    Pain is a negative emotional experience that is modulated by a variety of psychological factors through different inhibitory systems. For example, endogenous opioids and cannabinoids have been found to be involved in stress and placebo analgesia. Here we show that when the meaning of the pain experience is changed from negative to positive through verbal suggestions, the opioid and cannabinoid systems are co-activated and these, in turn, increase pain tolerance. We induced ischemic arm pain in healthy volunteers, who had to tolerate the pain as long as possible. One group was informed about the aversive nature of the task, as done in any pain study. Conversely, a second group was told that the ischemia would be beneficial to the muscles, thus emphasizing the usefulness of the pain endurance task. We found that in the second group pain tolerance was significantly higher compared to the first one, and that this effect was partially blocked by the opioid antagonist naltrexone alone and by the cannabinoid antagonist rimonabant alone. However, the combined administration of naltrexone and rimonabant antagonized the increased tolerance completely. Our results indicate that a positive approach to pain reduces the global pain experience through the co-activation of the opioid and cannabinoid systems. These findings may have a profound impact on clinical practice. For example, postoperative pain, which means healing, can be perceived as less unpleasant than cancer pain, which means death. Therefore, the behavioral and/or pharmacological manipulation of the meaning of pain can represent an effective approach to pain management.

  19. Co-activity of the trapezius and upper arm muscles with finger tapping at different rates and trunk postures.

    PubMed

    Schnoz, M; Läubli, T; Krueger, H

    2000-10-01

    In the context of finding a model that describes the pathophysiological mechanisms leading to muscle pain at low-intensity repetitive work, in this study we investigated whether a simplified finger motor task that requires little mental demand can cause increased muscle activity in the upper arms and neck, and examined the impact of the variation of two parameters, finger tapping rate and body posture. Using the 5th and 95th percentiles from the surface electromyogram of six muscles of the fingers, upper arm and neck, we determined the static and dynamic components of the muscle activity. Correlation methods were used to find a component in the muscle activity that originated from the rhythm of the finger tapping. Further investigations included tapping steadiness and finger force. It was found that in many, but not all subjects, low or even high activity was constantly present in the upper arm and trapezius muscles, sometimes even during relaxation. Fast tapping and a forward-leaning body posture caused considerable increases, while a slightly reclined posture helped to reduce co-activity. However, motor control patterns varied strongly between individuals. Since certain subjects showed no co-activity at all we can assume that trapezius and upper-arm activation is not necessarily required for the completion of a task similar to ours. This may explain why some VDU users develop work-related musculoskeletal disorders while others remain healthy.

  20. Downregulation of Steroid Receptor Coactivator-2 Modulates Estrogen-Responsive Genes and Stimulates Proliferation of MCF-7 Breast Cancer Cells

    PubMed Central

    Fenne, Ingvild S.; Helland, Thomas; Flågeng, Marianne H.; Dankel, Simon N.; Mellgren, Gunnar; Sagen, Jørn V.

    2013-01-01

    The p160/Steroid Receptor Coactivators SRC-1, SRC-2/GRIP1, and SRC-3/AIB1 are important regulators of Estrogen Receptor alpha (ERα) activity. However, whereas the functions of SRC-1 and SRC-3 in breast tumourigenesis have been extensively studied, little is known about the role of SRC-2. Previously, we reported that activation of the cAMP-dependent protein kinase, PKA, facilitates ubiquitination and proteasomal degradation of SRC-2 which in turn leads to inhibition of SRC-2-coactivation of ERα and changed expression of the ERα target gene, pS2. Here we have characterized the global program of transcription in SRC-2-depleted MCF-7 breast cancer cells using short-hairpin RNA technology, and in MCF-7 cells exposed to PKA activating agents. In order to identify genes that may be regulated through PKA-induced downregulation of SRC-2, overlapping transcriptional targets in response to the respective treatments were characterized. Interestingly, we observed decreased expression of several breast cancer tumour suppressor genes (e.g., TAGLN, EGR1, BCL11b, CAV1) in response to both SRC-2 knockdown and PKA activation, whereas the expression of a number of other genes implicated in cancer progression (e.g., RET, BCAS1, TFF3, CXCR4, ADM) was increased. In line with this, knockdown of SRC-2 also stimulated proliferation of MCF-7 cells. Together, these results suggest that SRC-2 may have an antiproliferative function in breast cancer cells. PMID:23936147

  1. The transcriptional co-activator LEDGF/p75 displays a dynamic scan-and-lock mechanism for chromatin tethering

    PubMed Central

    Hendrix, Jelle; Gijsbers, Rik; De Rijck, Jan; Voet, Arnout; Hotta, Jun-ichi; McNeely, Melissa; Hofkens, Johan; Debyser, Zeger; Engelborghs, Yves

    2011-01-01

    Nearly all cellular and disease related functions of the transcriptional co-activator lens epithelium-derived growth factor (LEDGF/p75) involve tethering of interaction partners to chromatin via its conserved integrase binding domain (IBD), but little is known about the mechanism of in vivo chromatin binding and tethering. In this work we studied LEDGF/p75 in real-time in living HeLa cells combining different quantitative fluorescence techniques: spot fluorescence recovery after photobleaching (sFRAP) and half-nucleus fluorescence recovery after photobleaching (hnFRAP), continuous photobleaching, fluorescence correlation spectroscopy (FCS) and an improved FCS method to study diffusion dependence of chromatin binding, tunable focus FCS. LEDGF/p75 moves about in nuclei of living cells in a chromatin hopping/scanning mode typical for transcription factors. The PWWP domain of LEDGF/p75 is necessary, but not sufficient for in vivo chromatin binding. After interaction with HIV-1 integrase via its IBD, a general protein–protein interaction motif, kinetics of LEDGF/p75 shift to 75-fold larger affinity for chromatin. The PWWP is crucial for locking the complex on chromatin. We propose a scan-and-lock model for LEDGF/p75, unifying paradoxical notions of transcriptional co-activation and lentiviral integration targeting. PMID:20974633

  2. Nuclear receptor ERR alpha and coactivator PGC-1 beta are effectors of IFN-gamma-induced host defense.

    PubMed

    Sonoda, Junichiro; Laganière, Josée; Mehl, Isaac R; Barish, Grant D; Chong, Ling-Wa; Li, Xiangli; Scheffler, Immo E; Mock, Dennis C; Bataille, Alain R; Robert, Francois; Lee, Chih-Hao; Giguère, Vincent; Evans, Ronald M

    2007-08-01

    Macrophage activation by the proinflammatory cytokine interferon-gamma (IFN-gamma) is a critical component of the host innate response to bacterial pathogenesis. However, the precise nature of the IFN-gamma-induced activation pathway is not known. Here we show using genome-wide expression and chromatin-binding profiling that IFN-gamma induces the expression of many nuclear genes encoding mitochondrial respiratory chain machinery via activation of the nuclear receptor ERR alpha (estrogen-related receptor alpha, NR3B1). Studies with macrophages lacking ERR alpha demonstrate that it is required for induction of mitochondrial reactive oxygen species (ROS) production and efficient clearance of Listeria monocytogenes (LM) in response to IFN-gamma. As a result, mice lacking ERR alpha are susceptible to LM infection, a phenotype that is localized to bone marrow-derived cells. Furthermore, we found that IFN-gamma-induced activation of ERR alpha depends on coactivator PGC-1 beta (peroxisome proliferator-activated receptor gamma coactivator-1 beta), which appears to be a direct target for the IFN-gamma/STAT-1 signaling cascade. Thus, ERR alpha and PGC-1 beta act together as a key effector of IFN-gamma-induced mitochondrial ROS production and host defense.

  3. DCA1 Acts as a Transcriptional Co-activator of DST and Contributes to Drought and Salt Tolerance in Rice.

    PubMed

    Cui, Long-Gang; Shan, Jun-Xiang; Shi, Min; Gao, Ji-Ping; Lin, Hong-Xuan

    2015-10-01

    Natural disasters, including drought and salt stress, seriously threaten food security. In previous work we cloned a key zinc finger transcription factor gene, Drought and Salt Tolerance (DST), a negative regulator of drought and salt tolerance that controls stomatal aperture in rice. However, the exact mechanism by which DST regulates the expression of target genes remains unknown. In the present study, we demonstrated that DST Co-activator 1 (DCA1), a previously unknown CHY zinc finger protein, acts as an interacting co-activator of DST. DST was found to physically interact with itself and to form a heterologous tetramer with DCA1. This transcriptional complex appears to regulate the expression of peroxidase 24 precursor (Prx 24), a gene encoding an H2O2 scavenger that is more highly expressed in guard cells. Downregulation of DCA1 significantly enhanced drought and salt tolerance in rice, and overexpression of DCA1 increased sensitivity to stress treatment. These phenotypes were mainly influenced by DCA1 and negatively regulated stomatal closure through the direct modulation of genes associated with H2O2 homeostasis. Our findings establish a framework for plant drought and salt stress tolerance through the DCA1-DST-Prx24 pathway. Moreover, due to the evolutionary and functional conservation of DCA1 and DST in plants, engineering of this pathway has the potential to improve tolerance to abiotic stress in other important crop species.

  4. The PGC-1 coactivators promote an anti-inflammatory environment in skeletal muscle in vivo

    SciTech Connect

    Eisele, Petra Sabine; Furrer, Regula; Beer, Markus

    2015-08-28

    The peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is abundantly expressed in trained muscles and regulates muscle adaptation to endurance exercise. Inversely, mice lacking a functional PGC-1α allele in muscle exhibit reduced muscle functionality and increased inflammation. In isolated muscle cells, PGC-1α and the related PGC-1β counteract the induction of inflammation by reducing the activity of the nuclear factor κB (NFκB). We now tested the effects of these metabolic regulators on inflammatory reactions in muscle tissue of control and muscle-specific PGC-1α/-1β transgenic mice in vivo in the basal state as well as after an acute inflammatory insult. Surprisingly, we observed a PGC-1-dependent alteration of the cytokine profile characterized by an increase in anti-inflammatory factors and a strong suppression of the pro-inflammatory interleukin 12 (IL-12). In conclusion, the anti-inflammatory environment in muscle that is promoted by the PGC-1s might contribute to the beneficial effects of these coactivators on muscle function and provides a molecular link underlying the tight mutual regulation of metabolism and inflammation. - Highlights: • Muscle PGC-1s are insufficient to prevent acute systemic inflammation. • The muscle PGC-1s however promote a local anti-inflammatory environment. • This anti-inflammatory environment could contribute to the therapeutic effect of the PGC-1s.

  5. Separate regions of glucocorticoid receptor, coactivator TIF2, and comodulator STAMP modify different parameters of glucocorticoid-mediated gene induction.

    PubMed

    Awasthi, Smita; Simons, S Stoney

    2012-05-15

    Increased specificity in steroid-regulated gene expression is a long-sought goal of endocrinologists. Considerable progress has resulted from the discovery of coactivators, corepressors, and comodulators that adjust the total activity (A(max)) of gene induction. Two less frequently quantitated, but equally potent, means of improving specificity are the concentration of agonist steroid required for half-maximal activity (EC(50)) and the residual or partial agonist activity displayed by most antisteroids (PAA). It is usually assumed that the modulatory activity of transcriptional cofactors coordinately regulates A(max), EC(50), and PAA. Here we examine the hypothesis that these three parameters can be independently modified by separate protein domains. The test system involves three differently sized fragments of each of three factors (glucocorticoid receptor [GR], coactivator TIF2, and comodulator STAMP), which are shown to form a ternary complex and similarly affect the induction properties of transfected and endogenous genes. Twenty-five different fragment combinations of the ternary complex are examined for their ability to modulate the A(max), EC(50), and PAA of a transiently transfected synthetic reporter gene. Different combinations selectively alter one, two, or all three parameters. These results clearly demonstrate that A(max), EC(50), and PAA can be independently regulated under some conditions by different pathways or molecular interactions. This new mechanistic insight suggests that selected activities of individual transcription factors are attractive targets for small molecules, which would have obvious clinical applications for increasing the specificity of steroids during endocrine therapies.

  6. The Child's Right To Play.

    ERIC Educational Resources Information Center

    Morris, Beverley

    This paper argues that play is an important and fundamental educational process and that the child's right to play should be respected. The paper also comments on the 1990 Tokyo International Conference on the Child's Right to Play. Several issues related to children's play, both in and out of school, are discussed. The focus is on the state of…

  7. Playful Learning and Montessori Education

    ERIC Educational Resources Information Center

    Lillard, Angeline S.

    2013-01-01

    Although Montessori education is often considered a form of playful learning, Maria Montessori herself spoke negatively about a major component of playful learning--pretend play, or fantasy--for young children. In this essay, the author discusses this apparent contradiction: how and why Montessori education includes elements of playful learning…

  8. Play Therapy in Elementary Schools

    ERIC Educational Resources Information Center

    Landreth, Garry L.; Ray, Dee C.; Bratton, Sue C.

    2009-01-01

    Because the child's world is a world of action and activity, play therapy provides the psychologist in elementary-school settings with an opportunity to enter the child's world. In the play therapy relationship, toys are like the child's words and play is the child's language. Therefore, children play out their problems, experiences, concerns, and…

  9. Play: Children's Context for Development.

    ERIC Educational Resources Information Center

    Klein, Tovah P.; Wirth, Daniele; Linas, Keri

    2003-01-01

    Defines the elements of play, illuminating its central role in young children's learning and development. Focuses on how play experiences contribute to children's independence in negotiating, its role in keeping children involved, and the play-reality distinction. Offers suggestions to teachers for facilitating and supporting children's play,…

  10. Play and Positive Group Dynamics

    ERIC Educational Resources Information Center

    Thompson, Pam; White, Samantha

    2010-01-01

    Play is an important part of a child's life and essential to learning and development (Vygotsky, 1978). It is vital that students participate in play and that play be conducted in a restorative manner. Play allows a variety of group dynamics to emerge. Irvin Yalom (1995) identifies 11 curative factors of the group experience. These factors include…

  11. GENERAL CONTROL NONREPRESSED PROTEIN5-Mediated Histone Acetylation of FERRIC REDUCTASE DEFECTIVE3 Contributes to Iron Homeostasis in Arabidopsis1

    PubMed Central

    Wang, Tianya; Liu, Zhenshan; Xu, Jianqin; Yao, Yingyin; Peng, Huiru; Xin, Mingming; Ni, Zhongfu

    2015-01-01

    Iron homeostasis is essential for plant growth and development. Here, we report that a mutation in GENERAL CONTROL NONREPRESSED PROTEIN5 (GCN5) impaired iron translocation from the root to the shoot in Arabidopsis (Arabidopsis thaliana). Illumina high-throughput sequencing revealed 879 GCN5-regulated candidate genes potentially involved in iron homeostasis. Chromatin immunoprecipitation assays indicated that five genes (At3G08040, At2G01530, At2G39380, At2G47160, and At4G05200) are direct targets of GCN5 in iron homeostasis regulation. Notably, GCN5-mediated acetylation of histone 3 lysine 9 and histone 3 lysine 14 of FERRIC REDUCTASE DEFECTIVE3 (FRD3) determined the dynamic expression of FRD3. Consistent with the function of FRD3 as a citrate efflux protein, the iron retention defect in gcn5 was rescued and fertility was partly restored by overexpressing FRD3. Moreover, iron retention in gcn5 roots was significantly reduced by the exogenous application of citrate. Collectively, these data suggest that GCN5 plays a critical role in FRD3-mediated iron homeostasis. Our results provide novel insight into the chromatin-based regulation of iron homeostasis in Arabidopsis. PMID:26002909

  12. Rough and Tumble Play 101

    ERIC Educational Resources Information Center

    Carlson, Frances

    2009-01-01

    Many people fear that play-fighting or rough and tumble play is the same as real fighting. There is also a fear that this rough play will become real fighting if allowed to continue. Most of all, parents and teachers fear that during the course of rough and tumble play a child may be hurt. To provide for and allow children to play rough without…

  13. Rough and Tumble Play 101

    ERIC Educational Resources Information Center

    Carlson, Frances

    2009-01-01

    Many people fear that play-fighting or rough and tumble play is the same as real fighting. There is also a fear that this rough play will become real fighting if allowed to continue. Most of all, parents and teachers fear that during the course of rough and tumble play a child may be hurt. To provide for and allow children to play rough without…

  14. Solar Power at Play

    NASA Astrophysics Data System (ADS)

    2007-03-01

    For the very first time, astronomers have witnessed the speeding up of an asteroid's rotation, and have shown that it is due to a theoretical effect predicted but never seen before. The international team of scientists used an armada of telescopes to discover that the asteroid's rotation period currently decreases by 1 millisecond every year, as a consequence of the heating of the asteroid's surface by the Sun. Eventually it may spin faster than any known asteroid in the solar system and even break apart. ESO PR Photo 11a/07 ESO PR Photo 11a/07 Asteroid 2000 PH5 "The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the Solar System rotate," said Stephen Lowry (Queens University Belfast, UK), lead-author of one of the two companion papers in which this work is reported [1, 2]. "The warming caused by sunlight hitting the surfaces of asteroids and meteoroids leads to a gentle recoil effect as the heat is released," he added. "By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning." Although this is an almost immeasurably weak force, its effect over millions of years is far from negligible. Astronomers believe the YORP effect may be responsible for spinning some asteroids up so fast that they break apart, perhaps leading to the formation of double asteroids. Others may be slowed down so that they take many days to complete a full turn. The YORP effect also plays an important role in changing the orbits of asteroids between Mars and Jupiter, including their delivery to planet-crossing orbits, such as those of near-Earth asteroids. Despite its importance, the effect has never been seen acting on a solar system body, until now. Using extensive optical and radar imaging from powerful Earth-based observatories, astronomers have directly observed the YORP effect in action on a small near-Earth asteroid, known as (54509) 2000 PH5. Shortly after its discovery in 2000, it was

  15. Play technique in psychodynamic psychotherapy.

    PubMed

    Yanof, Judith A

    2013-04-01

    Imaginary play is often a child's best way of communicating affects, fantasies, and internal states. In play children are freer to express their forbidden and conflicted thoughts. Consequently, one of the best ways for the therapist to enter the child's world is to do so from within the displacement of the play process. For children who cannot play, the therapist's goal is to teach the child to use play as a means of communication and to create meaning. This article present clinical examples to illustrate how the author uses play in the clinical situation.

  16. Coactivation of liver receptor homologue-1 by peroxisome proliferator-activated receptor gamma coactivator-1alpha on aromatase promoter II and its inhibition by activated retinoid X receptor suggest a novel target for breast-specific antiestrogen therapy.

    PubMed

    Safi, Rachid; Kovacic, Agnes; Gaillard, Stéphanie; Murata, Yoko; Simpson, Evan R; McDonnell, Donald P; Clyne, Colin D

    2005-12-15

    Aromatase inhibitors target the production of estrogen in breast adipose tissue, but in doing so, also decrease estrogen formation in bone and other sites, giving rise to deleterious side effects, such as bone loss and arthralgia. Thus, it would be clinically useful to selectively inhibit aromatase production in breast. In this regard, we have determined that the orphan nuclear receptor liver receptor homologue-1 (LRH-1) is a specific transcriptional activator of aromatase gene expression in human breast preadipocytes but not in other tissues of postmenopausal women. In this study, we show that the coactivator peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) is a physiologically relevant modulator of LRH-1, and that its transcriptional activity can be inhibited effectively using receptor-interacting peptide antagonists that prevent PGC-1alpha recruitment. Interestingly, we note that all of these peptides also interact in an agonist-dependent manner with retinoid X receptor alpha (RXRalpha), suggesting that these two receptors may compete for limiting cofactors within target cells. In support of this hypothesis, we show that 9-cis-retinoic acid, acting through RXR, inhibits both the basal and PGC-1alpha-induced transcriptional activity of LRH-1. The importance of this finding was confirmed by showing that LRH-1-dependent, PGC-1alpha-stimulated regulation of aromatase gene expression in primary human breast preadipocytes was effectively suppressed by RXR agonists. We infer from these data that LRH-1 is a bona fide target whose inhibition would selectively block aromatase expression in breast, while sparing other sites of expression.

  17. MicroRNA-22 and microRNA-140 suppress NF-{kappa}B activity by regulating the expression of NF-{kappa}B coactivators

    SciTech Connect

    Takata, Akemi; Otsuka, Motoyuki; Kojima, Kentaro; Yoshikawa, Takeshi; Kishikawa, Takahiro; Yoshida, Haruhiko; Koike, Kazuhiko

    2011-08-12

    Highlights: {yields} miRNAs were screened for their ability to regulate NF-{kappa}B activity. {yields} miRNA-22 and miRNA-140-3p suppress NF-{kappa}B activity by regulating coactivators. {yields} miRNA-22 targets nuclear receptor coactivator 1 (NCOA1). {yields} miRNA-140-3p targets nuclear receptor-interacting protein 1 (NRIP1). -- Abstract: Nuclear factor {kappa}B (NF-{kappa}B) is a transcription factor that regulates a set of genes that are critical to many biological phenomena, including liver tumorigenesis. To identify microRNAs (miRNAs) that regulate NF-{kappa}B activity in the liver, we screened 60 miRNAs expressed in hepatocytes for their ability to modulate NF-{kappa}B activity. We found that miRNA-22 and miRNA-140-3p significantly suppressed NF-{kappa}B activity by regulating the expression of nuclear receptor coactivator 1 (NCOA1) and nuclear receptor-interacting protein 1 (NRIP1), both of which are NF-{kappa}B coactivators. Our results provide new information about the roles of miRNAs in the regulation of NF-{kappa}B activity.

  18. Co-Activity during Maximum Voluntary Contraction: A Study of Four Lower-Extremity Muscles in Children with and without Cerebral Palsy

    ERIC Educational Resources Information Center

    Tedroff, Kristina; Knutson, Loretta M.; Soderberg, Gary L.

    2008-01-01

    This study was designed to determine whether children with cerebral palsy (CP) showed more co-activity than comparison children in non-prime mover muscles with regard to the prime mover during maximum voluntary isometric contraction (MVIC) of four lower-extremity muscles. Fourteen children with spastic diplegic CP (10 males, four females; age…

  19. Identification of a Novel LXXLL Motif in α-Actinin 4-spliced Isoform That Is Critical for Its Interaction with Estrogen Receptor α and Co-activators*

    PubMed Central

    Khurana, Simran; Chakraborty, Sharmistha; Zhao, Xuan; Liu, Yu; Guan, Dongyin; Lam, Minh; Huang, Wei; Yang, Sichun; Kao, Hung-Ying

    2012-01-01

    α-Actinins (ACTNs) are a family of proteins cross-linking actin filaments that maintain cytoskeletal organization and cell motility. Recently, it has also become clear that ACTN4 can function in the nucleus. In this report, we found that ACTN4 (full length) and its spliced isoform ACTN4 (Iso) possess an unusual LXXLL nuclear receptor interacting motif. Both ACTN4 (full length) and ACTN4 (Iso) potentiate basal transcription activity and directly interact with estrogen receptor α, although ACTN4 (Iso) binds ERα more strongly. We have also found that both ACTN4 (full length) and ACTN4 (Iso) interact with the ligand-independent and the ligand-dependent activation domains of estrogen receptor α. Although ACTN4 (Iso) interacts efficiently with transcriptional co-activators such as p300/CBP-associated factor (PCAF) and steroid receptor co-activator 1 (SRC-1), the full length ACTN4 protein either does not or does so weakly. More importantly, the flanking sequences of the LXXLL motif are important not only for interacting with nuclear receptors but also for the association with co-activators. Taken together, we have identified a novel extended LXXLL motif that is critical for interactions with both receptors and co-activators. This motif functions more efficiently in a spliced isoform of ACTN4 than it does in the full-length protein. PMID:22908231

  20. Safety Play Surfaces Buying Guide.

    ERIC Educational Resources Information Center

    Morris, Susan

    1990-01-01

    Describes standards for playing surfaces and characteristics of play surfaces made of organic loose material, inorganic loose material, and compact materials. Necessary site preparation is discussed. An extensive, annotated list of manufacturers of surfaces is included. (DR)

  1. Social Studies Teacher Writes Play.

    ERIC Educational Resources Information Center

    Papaleo, Ralph J.

    1985-01-01

    The text of a teacher-written play "The Tragedy of Woodrow Wilson" that can be used in high school social studies classes is presented. The author also discusses how he went about writing the play. (RM)

  2. Identification of Small-Molecule Enhancers of Arginine Methylation Catalyzed by Coactivator-Associated Arginine Methyltransferase 1

    PubMed Central

    Castellano, Sabrina; Spannhoff, Astrid; Milite, Ciro; Dal Piaz, Fabrizio; Cheng, Donghang; Tosco, Alessandra; Viviano, Monica; Yamani, Abdellah; Cianciulli, Agostino; Sala, Marina; Cura, Vincent; Cavarelli, Jean; Novellino, Ettore; Mai, Antonello; Bedford, Mark T.; Sbardella, Gianluca

    2012-01-01

    Arginine methylation is a common post-translational modification that is crucial in modulating gene expression at multiple critical levels. The arginine methyltransferases (PRMTs) are envisaged as promising druggable targets but their role in physiological and pathological pathways is far from being clear, due to the limited number of modulators reported to date. In this effort, enzyme activators can be invaluable tools useful as gain-of-function reagents to interrogate the biological roles in cells and in vivo of PRMTs. Yet the identification of such molecules is rarely pursued. Herein we describe a series of aryl ureido acetamido indole carboxylates (dubbed “uracandolates”), able to increase the methylation of histone- (H3) or non-histone (polyadenylate-binding protein 1, PABP1) substrates induced by coactivator-associated arginine methyltransferase 1 (CARM1), both in in vitro and cellular settings. To the best of our knowledge, this is the first report of compounds acting as CARM1 activators. PMID:23095008

  3. Identification of Novel Inhibitors against Coactivator Associated Arginine Methyltransferase 1 Based on Virtual Screening and Biological Assays

    PubMed Central

    Xie, Yiqian; Luo, Cheng

    2016-01-01

    Overexpression of coactivator associated arginine methyltransferase 1 (CARM1), a protein arginine N-methyltransferase (PRMT) family enzyme, is associated with various diseases including cancers. Consequently, the development of small-molecule inhibitors targeting PRMTs has significant value for both research and therapeutic purposes. In this study, together with structure-based virtual screening with biochemical assays, two compounds DC_C11 and DC_C66 were identified as novel inhibitors of CARM1. Cellular studies revealed that the two inhibitors are cell membrane permeable and effectively blocked proliferation of cancer cells including HELA, K562, and MCF7. We further predicted the binding mode of these inhibitors through molecular docking analysis, which indicated that the inhibitors competitively occupied the binding site of the substrate and destroyed the protein-protein interactions between CARM1 and its substrates. Overall, this study has shed light on the development of small-molecule CARM1 inhibitors with novel scaffolds. PMID:27872854

  4. Problematic Game Play: The Diagnostic Value of Playing Motives, Passion, and Playing Time in Men

    PubMed Central

    Kneer, Julia; Rieger, Diana

    2015-01-01

    Internet gaming disorder is currently listed in the DSM—not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing. PMID:25942516

  5. Problematic game play: the diagnostic value of playing motives, passion, and playing time in men.

    PubMed

    Kneer, Julia; Rieger, Diana

    2015-04-30

    Internet gaming disorder is currently listed in the DSM-not in order to diagnose such a disorder but to encourage research to investigate this phenomenon. Even whether it is still questionable if Internet Gaming Disorder exists and can be judged as a form of addiction, problematic game play is already very well researched to cause problems in daily life. Approaches trying to predict problematic tendencies in digital game play have mainly focused on playing time as a diagnostic criterion. However, motives to engage in digital game play and obsessive passion for game play have also been found to predict problematic game play but have not yet been investigated together. The present study aims at (1) analyzing if obsessive passion can be distinguished from problematic game play as separate concepts, and (2) testing motives of game play, passion, and playing time for their predictive values for problematic tendencies. We found (N = 99 males, Age: M = 22.80, SD = 3.81) that obsessive passion can be conceptually separated from problematic game play. In addition, the results suggest that compared to solely playing time immersion as playing motive and obsessive passion have added predictive value for problematic game play. The implications focus on broadening the criteria in order to diagnose problematic playing.

  6. Piaget, Play and Cognition, Revisited.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Piaget's early contribution to theorizing about play is discussed critically with reference to three major interrelated problems. These are: (1) that despite their equipotentiality in Piaget's theory of intelligence, imitation and play are not conceptualized as making an equal contribution to cognition, play taking a subordinate role; (2) that…

  7. Play Memories and Place Identity.

    ERIC Educational Resources Information Center

    Sandberg, Anette

    2003-01-01

    This retrospective study examined play memories from childhood to adulthood of 478 university students between ages 20 and 62 as exhibited in drawings of play memories and questionnaire responses. The study focused on the role of the physical environment and place identity in play memories and individual identity development. Findings showed that…

  8. Piaget, Play and Cognition, Revisited.

    ERIC Educational Resources Information Center

    Sutton-Smith, Brian

    Piaget's early contribution to theorizing about play is discussed critically with reference to three major interrelated problems. These are: (1) that despite their equipotentiality in Piaget's theory of intelligence, imitation and play are not conceptualized as making an equal contribution to cognition, play taking a subordinate role; (2) that…

  9. Meanings of Play among Children

    ERIC Educational Resources Information Center

    Glenn, Nicole M.; Knight, Camilla J.; Holt, Nicholas L.; Spence, John C.

    2013-01-01

    The purpose of this study was to examine meanings of play among children. Thirty-eight students aged 7-9 years from a suburban public school in Western Canada participated in focus groups. Data analysis revealed participants saw almost anything as an opportunity for play and would play almost anywhere with anyone. However, they perceived parents…

  10. The Values of Outdoor Play

    ERIC Educational Resources Information Center

    Elkind, David

    2006-01-01

    This article describes outdoor play as a solid foundation and a central vehicle of knowledge about the real world. Outdoor play is important to all age levels, but particularly in early childhood and the elementary years. Children's outdoor play is not a luxury. It is critical in children's ability to learn about the world, others, and themselves.…

  11. Preschoolers' Thinking during Block Play

    ERIC Educational Resources Information Center

    Piccolo, Diana L.; Test, Joan

    2010-01-01

    Children build foundations for mathematical thinking in early play and exploration. During the preschool years, children enjoy exploring mathematical concepts--such as patterns, shape, spatial relationships, and measurement--leading them to spontaneously engage in mathematical thinking during play. Block play is one common example that engages…

  12. Meanings of Play among Children

    ERIC Educational Resources Information Center

    Glenn, Nicole M.; Knight, Camilla J.; Holt, Nicholas L.; Spence, John C.

    2013-01-01

    The purpose of this study was to examine meanings of play among children. Thirty-eight students aged 7-9 years from a suburban public school in Western Canada participated in focus groups. Data analysis revealed participants saw almost anything as an opportunity for play and would play almost anywhere with anyone. However, they perceived parents…

  13. Play in Evolution and Development

    ERIC Educational Resources Information Center

    Pellegrini, Anthony D.; Dupuis, Danielle; Smith, Peter K.

    2007-01-01

    In this paper we examine the role of play in human ontogeny and phylogeny, following Surplus Resource Theory. We consider how juveniles use play to sample their environment in order to develop adaptive behaviors. We speculate about how innovative behaviors developed in play in response to environmental novelty may influence subsequent evolutionary…

  14. Play Memories and Place Identity.

    ERIC Educational Resources Information Center

    Sandberg, Anette

    2003-01-01

    This retrospective study examined play memories from childhood to adulthood of 478 university students between ages 20 and 62 as exhibited in drawings of play memories and questionnaire responses. The study focused on the role of the physical environment and place identity in play memories and individual identity development. Findings showed that…

  15. Play in Evolution and Development

    ERIC Educational Resources Information Center

    Pellegrini, Anthony D.; Dupuis, Danielle; Smith, Peter K.

    2007-01-01

    In this paper we examine the role of play in human ontogeny and phylogeny, following Surplus Resource Theory. We consider how juveniles use play to sample their environment in order to develop adaptive behaviors. We speculate about how innovative behaviors developed in play in response to environmental novelty may influence subsequent evolutionary…

  16. Play Therapy in School Counseling

    ERIC Educational Resources Information Center

    Trice-Black, Shannon; Bailey, Carrie Lynn; Kiper Riechel, Morgan E.

    2013-01-01

    Play therapy is an empirically supported intervention used to address a number of developmental issues faced in childhood. Through the natural language of play, children and adolescents communicate feelings, thoughts, and experiences. Schools provide an ideal setting for play therapy in many ways; however, several challenges exist in implementing…

  17. Pretend Play and Creative Processes

    ERIC Educational Resources Information Center

    Russ, Sandra W.; Wallace, Claire E.

    2013-01-01

    The authors contend that many cognitive abilities and affective processes important in creativity also occur in pretend play and that pretend play in childhood affects the development of creativity in adulthood. They discuss a variety of theories and observations that attempt to explain the importance of pretend play to creativity. They argue that…

  18. Play Therapy in School Counseling

    ERIC Educational Resources Information Center

    Trice-Black, Shannon; Bailey, Carrie Lynn; Kiper Riechel, Morgan E.

    2013-01-01

    Play therapy is an empirically supported intervention used to address a number of developmental issues faced in childhood. Through the natural language of play, children and adolescents communicate feelings, thoughts, and experiences. Schools provide an ideal setting for play therapy in many ways; however, several challenges exist in implementing…

  19. The Values of Outdoor Play

    ERIC Educational Resources Information Center

    Elkind, David

    2006-01-01

    This article describes outdoor play as a solid foundation and a central vehicle of knowledge about the real world. Outdoor play is important to all age levels, but particularly in early childhood and the elementary years. Children's outdoor play is not a luxury. It is critical in children's ability to learn about the world, others, and themselves.…

  20. The elongation complex components BRD4 and MLLT3/AF9 are transcriptional coactivators of nuclear retinoid receptors.

    PubMed

    Flajollet, Sébastien; Rachez, Christophe; Ploton, Maheul; Schulz, Céline; Gallais, Rozenn; Métivier, Raphaël; Pawlak, Michal; Leray, Aymeric; Issulahi, Al Amine; Héliot, Laurent; Staels, Bart; Salbert, Gilles; Lefebvre, Philippe

    2013-01-01

    Nuclear all-trans retinoic acid receptors (RARs) initiate early transcriptional events which engage pluripotent cells to differentiate into specific lineages. RAR-controlled transactivation depends mostly on agonist-induced structural transitions in RAR C-terminus (AF-2), thus bridging coactivators or corepressors to chromatin, hence controlling preinitiation complex assembly. However, the contribution of other domains of RAR to its overall transcriptional activity remains poorly defined. A proteomic characterization of nuclear proteins interacting with RAR regions distinct from the AF-2 revealed unsuspected functional properties of the RAR N-terminus. Indeed, mass spectrometry fingerprinting identified the Bromodomain-containing protein 4 (BRD4) and ALL1-fused gene from chromosome 9 (AF9/MLLT3), known to associate with and regulates the activity of Positive Transcription Elongation Factor b (P-TEFb), as novel RAR coactivators. In addition to promoter sequences, RAR binds to genomic, transcribed regions of retinoid-regulated genes, in association with RNA polymerase II and as a function of P-TEFb activity. Knockdown of either AF9 or BRD4 expression affected differentially the neural differentiation of stem cell-like P19 cells. Clusters of retinoid-regulated genes were selectively dependent on BRD4 and/or AF9 expression, which correlated with RAR association to transcribed regions. Thus RAR establishes physical and functional links with components of the elongation complex, enabling the rapid retinoid-induced induction of genes required for neuronal differentiation. Our data thereby extends the previously known RAR interactome from classical transcriptional modulators to components of the elongation machinery, and unravel a functional role of RAR in transcriptional elongation.