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Ashton AW, Dhanjal HK, Rossner B, Mahmood H, Patel VI, Nadim M, Lota M, Shahid F, Li Z, Joyce D, Pajkos M, Dosztányi Z, Jiao X, Pestell RG. Acetylation of nuclear receptors in health and disease: an update. FEBS J 2024; 291:217-236. [PMID: 36471658 DOI: 10.1111/febs.16695] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/17/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Lysine acetylation is a common reversible post-translational modification of proteins that plays a key role in regulating gene expression. Nuclear receptors (NRs) include ligand-inducible transcription factors and orphan receptors for which the ligand is undetermined, which together regulate the expression of genes involved in development, metabolism, homeostasis, reproduction and human diseases including cancer. Since the original finding that the ERα, AR and HNF4 are acetylated, we now understand that the vast majority of NRs are acetylated and that this modification has profound effects on NR function. Acetylation sites are often conserved and involve both ordered and disordered regions of NRs. The acetylated residues function as part of an intramolecular signalling platform intersecting phosphorylation, methylation and other modifications. Acetylation of NR has been shown to impact recruitment into chromatin, co-repressor and coactivator complex formation, sensitivity and specificity of regulation by ligand and ligand antagonists, DNA binding, subcellular distribution and transcriptional activity. A growing body of evidence in mice indicates a vital role for NR acetylation in metabolism. Additionally, mutations of the NR acetylation site occur in human disease. This review focuses on the role of NR acetylation in coordinating signalling in normal physiology and disease.
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Affiliation(s)
- Anthony W Ashton
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
- Lankenau Institute for Medical Research, Wynnewood, PA, USA
| | | | - Benjamin Rossner
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Huma Mahmood
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Vivek I Patel
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Mohammad Nadim
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Manpreet Lota
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Farhan Shahid
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
| | - Zhiping Li
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Wynnewood, PA, USA
| | - David Joyce
- Medical School, Faculty of Health and Medical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Matyas Pajkos
- Department of Biochemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Zsuzsanna Dosztányi
- Department of Biochemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Xuanmao Jiao
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Wynnewood, PA, USA
| | - Richard G Pestell
- Xavier University School of Medicine at Aruba, Oranjestad, Aruba
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Wynnewood, PA, USA
- The Wistar Cancer Center, Philadelphia, PA, USA
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2
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Vella KR, Hollenberg AN. The actions of thyroid hormone signaling in the nucleus. Mol Cell Endocrinol 2017; 458:127-135. [PMID: 28286327 PMCID: PMC5592130 DOI: 10.1016/j.mce.2017.03.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 12/15/2022]
Abstract
Thyroid hormones are a critical regulator of mammalian physiology. Much of their action is due to effects in the nucleus where T3 engages thyroid hormone receptor isoforms to mediate its effects. In order to function properly the TR isoforms must be recruited to regulatory sequences within genes that they up-regulate. On these positive regulated target genes the TR can activate or repress depending upon whether the receptor is bound to T3 or not and the type of co-regulatory proteins present in that cell type. In contrast to T3 mediated activation, the mechanism by which the TR represses transcription in the presence of T3 remains unclear. Herein we will review the components of the transcriptional response to T3 within the nucleus and attempt to highlight the outstanding questions in the field.
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Affiliation(s)
- Kristen R Vella
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Anthony N Hollenberg
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States.
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Murakami S, Nagari A, Kraus WL. Dynamic assembly and activation of estrogen receptor α enhancers through coregulator switching. Genes Dev 2017; 31:1535-1548. [PMID: 28887413 PMCID: PMC5630019 DOI: 10.1101/gad.302182.117] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/14/2017] [Indexed: 12/11/2022]
Abstract
Although many features of active transcriptional enhancers have been defined by genomic assays, we lack a clear understanding of the order of events leading to enhancer formation and activation as well as the dynamics of coregulator interactions within the enhancer complex. Here, we used selective loss- or gain-of-function mutants of estrogen receptor α (ERα) to define two distinct phases of ligand-dependent enhancer formation. In the first phase (0-20 min), p300 is recruited to ERα by Mediator as well as p300's acetylhistone-binding bromodomain to promote initial enhancer formation, which is not competent for sustained activation. In the second phase (20-45 min), p300 is recruited to ERα by steroid receptor coregulators (SRCs) for enhancer maturation and maintenance. Successful transition between these two phases ("coregulator switching") is required for proper enhancer function. Failure to recruit p300 during either phase leads to abortive enhancer formation and a lack of target gene expression. Our results reveal an ordered and cooperative assembly of ERα enhancers requiring functional interplay among p300, Mediator, and SRCs, which has implications for hormone-dependent gene regulation in breast cancers. More broadly, our results demonstrate the unexpectedly dynamic nature of coregulator interactions within enhancer complexes, which are likely to be a defining feature of all enhancers.
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Affiliation(s)
- Shino Murakami
- The Laboratory of Signaling and Gene Expression, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,The Division of Basic Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,Program in Genetics, Development, and Disease, Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Anusha Nagari
- The Laboratory of Signaling and Gene Expression, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,The Division of Basic Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - W Lee Kraus
- The Laboratory of Signaling and Gene Expression, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,The Division of Basic Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,Program in Genetics, Development, and Disease, Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
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4
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Yu M, Gilbert S, Li Y, Zhang H, Qiao Y, Lu Y, Tang Y, Zhen Q, Cheng Y, Liu Y. Association of NCOA3 polymorphisms with Dyslipidemia in the Chinese Han population. Lipids Health Dis 2015; 14:124. [PMID: 26449542 PMCID: PMC4599759 DOI: 10.1186/s12944-015-0126-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 09/30/2015] [Indexed: 01/18/2023] Open
Abstract
Background Nuclear receptor coactivator-3 (NCOA3) is involved in various physiological processes. Emerging evidence from previous studies using animal models suggests that the NCOA3 gene (NCOA3) plays a critical role in lipid metabolism as well as adipogenesis and obesity. The present study aims to investigate the association between NCOA3 SNPs and dyslipidemia in the Chinese Han population. Methods Five hundred and twenty-nine (529) Chinese Han subjects were recruited. Four tag SNPs (rs2425955G > T, rs6066394T > C, rs10485463C > G, and rs6094753G > A) in NCOA3, selected from the HapMap website, were genotyped using MALDI-TOF mass spectrometry. Data analysis was performed using SPSS 16.0, SNPStats and haploview 4.2. Results Four SNPs (rs2425955, rs6066394, rs10485463, and rs6094753) were associated with triglyceride levels. Except for SNP rs10485463, genotype distributions and allele frequencies of the other three NCOA3 SNPs (rs2425955, rs6066394, and rs6094753) were significantly different between hypertriglyceridemia subjects and normal group. Significant differences were also observed in allele frequencies and genotype distributions of SNP rs10485463 between low-HDL cholesterolemia subjects and normal group. Carriers of rs2425955 T allele had a lower risk of hypertriglyceridemia compared to GG genotype. Similar results were observed from rs6094753. Subjects with rs6066394 CT genotype had a lower risk of hypertriglyceridemia than those with the TT genotype; however, CC and TT genotypes showed no significant difference in the risk of hypertriglyceridemia. Similar results were found in the association between rs6066394 and hypercholesterolemia. The variant alleles of rs2425955, rs6066394 and rs6094753 were associated with a lower risk of hypertriglyceridemia compared with the wild-type alleles. The G allele of rs10485463 was associated with an increased risk of low-HDL cholesterolemia. In the log-additive model the association between rs2425955 and hypertriglyceridemia remained significant after Bonferroni correction, and genotypes with variant alleles were associated with a lower risk of hypertriglyceridemia. Conclusions In summary, this study demonstrated that variation in NCOA3 might influence the risk of dyslipidemia and serum lipid levels in Chinese Han population.
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Affiliation(s)
- Mingxi Yu
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Siame Gilbert
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Yong Li
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Huiping Zhang
- Department of Psychiatry, Yale University School of Medicine, VA Medical, Center/116A2, 950 Campbell Avenue, West Haven, CT, 06516, USA.
| | - Yichun Qiao
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Yuping Lu
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Yuan Tang
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Qing Zhen
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
| | - Yi Cheng
- The Cardiovascular Center, The First Hospital of Jilin University, Changchun, 130021, China.
| | - Yawen Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, 130021, China.
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5
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Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP. Proc Natl Acad Sci U S A 2010; 107:12535-40. [PMID: 20616042 DOI: 10.1073/pnas.1001693107] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Native molten globules are the most folded kind of intrinsically disordered proteins. Little is known about the mechanism by which native molten globules bind to their cognate ligands to form fully folded complexes. The nuclear coactivator binding domain (NCBD) of CREB binding protein is particularly interesting in this respect as structural studies of its complexes have shown that NCBD folds into two remarkably different states depending on the ligand being ACTR or IRF-3. The ligand-free state of NCBD was characterized in order to understand the mechanism of folding upon ligand binding. Biophysical studies show that despite the molten globule nature of the domain, it contains a small cooperatively folded core. By NMR spectroscopy, we have demonstrated that the folded core of NCBD has a well ordered conformer with specific side chain packing. This conformer resembles the structure of the NCBD in complex with the protein ligand, ACTR, suggesting that ACTR binds to prefolded NCBD molecules from the ensemble of interconverting structures.
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Gambogic acid induces G0/G1 arrest and apoptosis involving inhibition of SRC-3 and inactivation of Akt pathway in K562 leukemia cells. Toxicology 2009; 262:98-105. [PMID: 19433130 DOI: 10.1016/j.tox.2009.04.059] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 04/29/2009] [Accepted: 04/30/2009] [Indexed: 12/14/2022]
Abstract
Gambogic acid (GA), a major active component of gamboge, exhibits potent anticancer activity in many kinds of cancer cells. However, the anticancer mechanism of GA is not clearly understood. Here we showed that GA could cause growth inhibition, induce the G0/G1 phase cell cycle arrest and apoptosis in human chronic myelogenous leukemia cell line K562 cells. Since steroid receptor coactivator-3 (SRC-3), overexpressed in many human malignancies including leukemia, is a central target for cancer therapy, we also explored the effects of GA on SRC-3 and SRC-3-regulated gene products in K562. GA treatment downregulated the expression of SRC-3 and then inhibited the activity of Akt kinase and its downstream targets p70 S6 kinase 1 (S6K1) and glycogen synthase kinase 3beta (GSK3beta) without changes in total protein levels of these three proteins, which thus influenced the expression of the apoptosis related gene Bcl-2 in K562 cells. These results suggest that GA might exhibit its strong antitumor effects via the interruption of SRC-3.
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Li R, Chen Y, Shu WX, Chen Z, Ke WJ. Involvement of SRC-3 in deguelin-induced apoptosis in Jurkat cells. Int J Hematol 2009; 89:628-35. [PMID: 19365708 DOI: 10.1007/s12185-009-0311-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/22/2009] [Accepted: 03/24/2009] [Indexed: 10/20/2022]
Abstract
The aim of the study was to investigate the anticancer effects and the molecular mechanisms of deguelin on Jurkat cells. Cell viability was assessed by MTT assay. Terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay and transmission electron microscopy were used to detect cell apoptosis. A propidium iodide method was used to study cell cycle distribution. RT-PCR and Western blotting were employed to assess the expression levels of steroid receptor coactivator-3 (SRC-3), nuclear factor-kappaB (NF-kappaB) and some apoptosis related genes, including Bcl-2 and Bcl-xL. Deguelin was able to inhibit cell proliferation by a cell-cycle arrest in the G(1)/G(0) phase and induce apoptosis in Jurkat cells in vitro, with a 24-h IC(50) value of 43.73 +/- 0.35 nmol/L. The antileukemia effect of deguelin might be correlated well with the downregulation of the expression of SRC-3 and its related transcription factor NF-kappaB, which thus influenced the expression of apoptosis related genes Bcl-2 and Bcl-xL. Deguelin presented potent effects on growth arrest and apoptosis induction in Jurkat cells in vitro via the interruption of SRC-3.
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Affiliation(s)
- Rui Li
- Department of Hematology Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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8
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Li HJ, Haque ZK, Chen A, Mendelsohn M. RIF-1, a novel nuclear receptor corepressor that associates with the nuclear matrix. J Cell Biochem 2007; 102:1021-35. [PMID: 17455211 DOI: 10.1002/jcb.21340] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The retinoic acid receptors (RARs) are ligand-dependent transcription factors that play critical roles in cell differentiation, embryonic development, and tumor suppression. RAR transcriptional activities are mediated by a growing family of nuclear receptor (NR) coregulators. Here we report the cloning and characterization of a novel protein RIF1 (receptor interacting factor) that interacts with RARalpha in vivo and in vitro. RIF1 encodes a novel 739 amino acid protein that is ubiquitously expressed in a variety of tissues and cell lines. GST-pull down assays show that RIF1 also interacts with a number of other NRs. The interaction domain of RIF1 for RARalpha is located at the C-terminal region of RIF1, between amino acids 512 and 674. RIF1 is localized exclusively in the cell nucleus and specifically to the nuclear matrix. Mutation of the nuclear localization signal abolishes this nuclear localization and causes RIF1 to appear in the cytoplasm. Co-transfection of RIF1 with RAR causes RAR to localize to the nuclear matrix. RIF1 contains a strong transcriptional repression domain that robustly inhibits ligand-dependent transcriptional activation by RARalpha. This domain is located to the distal C-terminal 100 amino acids, distinct from the RARalpha-interaction and nuclear matrix-targeting domains. The transcriptional repression activity of RIF1 is mediated at least in part through direct recruitment of histone deacetylases. This study identifies RIF1 as a novel nuclear matrix transcription repressor, and suggests a potential role of RIF1 that regulates NR transcriptional activity.
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Affiliation(s)
- Hui Joyce Li
- Molecular Cardiology Research Institute, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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9
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Mussi P, Yu C, O'Malley BW, Xu J. Stimulation of Steroid Receptor Coactivator-3 (SRC-3) Gene Overexpression by a Positive Regulatory Loop of E2F1 and SRC-3. Mol Endocrinol 2006; 20:3105-19. [PMID: 16916939 DOI: 10.1210/me.2005-0522] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Abstract
Steroid receptor coactivator 3 (SRC-3, amplified in breast cancer 1, or ACTR) is a transcriptional coactivator for nuclear receptors and certain other transcription factors such as E2F1. SRC-3 is overexpressed in breast cancers, and its overexpression is sufficient to cause mammary carcinomas in vivo. However, the mechanisms controlling endogenous SRC-3 overexpression are unknown. In this study, we identified the first exon and analyzed the 5′ regulatory sequence of the SRC-3 gene. We found three evolutionarily conserved regions (ECRs) in the 5′ SRC-3 regulatory sequence, and ECR2 makes a major contribution to the SRC-3 promoter activity. The ECR2 region (bp −250/+350) contains several specificity protein 1 (Sp1) binding sites and two E2F1 binding sites. We show that E2F1 can significantly activate the ECR2 promoter activity in a dose-dependent manner. Furthermore, overexpression of E2F1 significantly increases the promoter activity of the endogenous SRC-3 gene and boosts SRC-3 expression in vivo. Conversely, knockdown of E2F1 reduces SRC-3 expression. We demonstrate that the mechanism of E2F1 activity on SRC-3 promoter is independent of the E2F binding sites but relies on the Sp1 element located at bp +150/+160. Sp1, E2F1, and SRC-3 are specifically recruited to this Sp1 site and the interaction between E2F1 and Sp1 is essential to modulate SRC-3 expression. Moreover, SRC-3 coactivates E2F1 activity and thereby additively stimulates a further increase in SRC-3 expression in vivo. These results suggest that in cells with hyperactive E2F1, such as the case encountered in breast cancer cells, there is a positive feedback regulatory loop consisting of E2F1 and SRC-3 to maintain high levels of SRC-3 and E2F1 activity, which may partially interpret the oncogenic role of SRC-3 overexpression.
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Affiliation(s)
- Paola Mussi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA
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10
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Jaber BM, Gao T, Huang L, Karmakar S, Smith CL. The pure estrogen receptor antagonist ICI 182,780 promotes a novel interaction of estrogen receptor-alpha with the 3',5'-cyclic adenosine monophosphate response element-binding protein-binding protein/p300 coactivators. Mol Endocrinol 2006; 20:2695-710. [PMID: 16840538 DOI: 10.1210/me.2005-0218] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Estrogen receptor-alpha (ERalpha) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. Abundant evidence demonstrates that ERalpha agonists promote, whereas antagonists inhibit, receptor binding to coactivators. In this report we demonstrate that binding of the ICI 182,780 (ICI) pure antiestrogen to ERalpha promotes its interaction with the cAMP response element-binding protein-binding protein (CBP)/p300 but not the p160 family of coactivators, demonstrating the specificity of this interaction. Amino acid mutations within the coactivator binding surface of the ERalpha ligand-binding domain revealed that CBP binds to this region of the ICI-liganded receptor. The carboxy-terminal cysteine-histidine rich domain 3 of CBP, rather than its amino-terminal nuclear interacting domain, shown previously to mediate agonist-dependent interactions of CBP with nuclear receptors, is required for binding to ICI-liganded ERalpha. Chromatin immunoprecipitation assays revealed that ICI but not the partial agonist/antagonist 4-hydroxytamoxifen is able to recruit CBP to the pS2 promoter, and this distinguishes ICI from this class of antiestrogens. Chromatin immunoprecipitation assays for pS2 and cytochrome P450 1B1 promoter regions revealed that ICI-dependent recruitment of CBP, but not receptor, to ERalpha targets is gene specific. ICI treatment did not recruit the steroid receptor coactivator 1 to the pS2 promoter, and it failed to induce the expression of this gene. Taken together, these data indicate that recruitment of the CBP coactivator/cointegrator without steroid receptor coactivator 1 to ERalpha is insufficient to promote transcription of ERalpha target genes.
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Affiliation(s)
- Basem M Jaber
- Molecular and Cellular Biology, One Baylor Plaza, Houston, Texas 77030, USA
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11
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Yeung PL, Zhang A, Chen JD. Nuclear localization of coactivator RAC3 is mediated by a bipartite NLS and importin alpha3. Biochem Biophys Res Commun 2006; 348:13-24. [PMID: 16875678 DOI: 10.1016/j.bbrc.2006.06.163] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Accepted: 06/26/2006] [Indexed: 10/24/2022]
Abstract
The nuclear receptor coactivator RAC3 (also known as SRC-3/ACTR/AIB1/p/CIP/TRAM-1) belongs to the p160 coactivator family, which are involved in several physiological processes and diseases. Here we have investigated how RAC3 is translocated into the nucleus and show that it is mediated through a bipartite NLS and importin alpha3. This bipartite NLS is located within the conserved bHLH domain, and its mutation abolished nuclear localization. The NLS is also sufficient to cause nuclear import of EGFP, and the activity requires basic amino acids within the NLS. RAC3 binds strongly to importin alpha3, which also depends on the basic amino acids. Functionally, RAC3 cytoplasmic mutant loses its ability to enhance transcription, suggesting that nuclear localization is essential for coactivator function. Together, these results reveal a previous unknown mechanism for nuclear translocation of p160 coactivators and a critical function of the conserved bHLH within the coactivator.
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Affiliation(s)
- Percy Luk Yeung
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ, USA
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12
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Hwang SL, Chang JH, Cheng TS, Sy WD, Lieu AS, Lin CL, Lee KS, Howng SL, Hong YR. Expression of Rac3 in human brain tumors. J Clin Neurosci 2006; 12:571-4. [PMID: 15993075 DOI: 10.1016/j.jocn.2004.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Accepted: 08/02/2004] [Indexed: 11/22/2022]
Abstract
Rac3 may play an important role in tumor growth but little is known about its expression and mutation in human tumor tissues. We examined the expression of Rac3 using RT-PCR and mutation of the Rac3 gene by DNA sequencing. Overexpression of the Rac3 gene occurred in 19% (5/26) of brain tumors; 3 of 9 (33%) meningiomas, 1 of 11 (9%) astrocytomas and 1 of 6 (17%) pituitary adenomas. Two of the 3 meningiomas with Rac3 overexpression were recurrent meningiomas. The only astrocytoma with Rac3 overexpression was a glioblastoma multiforme. Mutation of the Rac3 gene occurred in 63% (12/19) of brain tumours; 4 of 7 (57.1%) meningiomas, 4 of 5 (80%) pituitary adenomas and 4 of 7 (57.1%) astrocytomas. Except in one astrocytoma, the other four tumors with Rac3 overexpression (3 meningiomas and one pituitary adenoma) did not have Rac3 mutations. Our data is the first report of the frequency of Rac3 overexpression and mutation in human brain tumors. Overexpression may be associated with aggressive tumor behavior. The relationship between Rac3 expression and mutation requires further investigation.
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Affiliation(s)
- Shiuh-Lin Hwang
- Division of Neurosurgery, Kaohsiung Medical Universiy, Kaohsiung, Taiwan
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13
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Georgescu SP, Li JH, Lu Q, Karas RH, Brown M, Mendelsohn ME. Modulator Recognition Factor 1, an AT-Rich Interaction Domain Family Member, Is a Novel Corepressor for Estrogen Receptor α. Mol Endocrinol 2005; 19:2491-501. [PMID: 15941852 DOI: 10.1210/me.2004-0311] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cardiovascular tissues are important targets of estrogen action. Vascular cells express the two known estrogen receptors (ERs), ERalpha and ERbeta, ligand-activated transcription factors that regulate gene transcription through interactions with both coactivator and corepressor molecules. To isolate ERalpha coregulators in vascular cells, we performed a yeast two-hybrid screen for ERalpha-interacting proteins using a human aorta library. Here we report the identification of modulator recognition factor 1 (MRF1) as an ERalpha-interacting corepressor protein. Full-length MRF1 binds to both the N terminus and the C terminus of ERalpha. ERalpha and MRF1 coimmunoprecipitate in an estradiol-independent manner, and recombinant ERalpha binds to both full-length and COOH-terminal MRF1 in the absence of estradiol. MRF1 also interacts in a ligand-dependent manner with thyroid receptor alpha, retinoid X receptor alpha, and androgen receptor, and in a ligand-independent manner with ERbeta and the retinoic acid receptor. MRF1 RNA is highly expressed in aorta, heart, skeletal muscle, and liver. MRF1 has intrinsic repressor activity in an in vitro GAL reporter assay. Transient transfection studies show that MRF1 represses transcription by ERalpha activated by estradiol in a dose-dependent manner, as well as by the selective ER modulators 4-hydroxy-tamoxifen and raloxifene. MRF1 repression is not influenced by pharmacological inhibition of histone deacetylase. These data identify MRF1 as a repressor of ERalpha-mediated transcriptional activation and support a role for MRF1 in regulating ER-dependent gene expression in cardiovascular and other cells.
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Affiliation(s)
- Serban P Georgescu
- Molecular Cardiology Research Institute, New England Medical Center and Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111,USA
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Hussein-Fikret S, Fuller PJ. Expression of nuclear receptor coregulators in ovarian stromal and epithelial tumours. Mol Cell Endocrinol 2005; 229:149-60. [PMID: 15607539 DOI: 10.1016/j.mce.2004.08.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Accepted: 08/11/2004] [Indexed: 10/26/2022]
Abstract
Granulosa cell tumours of the ovary (GCT) exhibit high expression of estrogen receptor beta (ERbeta). A role for estrogen receptors in these tumours may depend on altered co-activator expression. This study examines the expression of the co-activators SRC-1a/e, SRC-2, SRC-3, SRA, and the corepressors NCoR and SMRT in GCT, epithelial ovarian tumours and normal ovary. No significant difference in the expression of SRC-1, SRC-2, SRC-3 or NCoR and SMRT was found. In particular, there was no correlation of co-activator expression with ERbeta expression. There was a significant upregulation in the expression of the novel RNA co-activator SRA in the serous tumours compared with the other tumour types and normal ovary. The findings suggest that ERbeta may require co-activators, other than members of the SRC family for the modulation of transcription in GCT.
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MESH Headings
- Acetyltransferases
- Adult
- Aged
- Aged, 80 and over
- Case-Control Studies
- Cystadenocarcinoma, Mucinous/genetics
- Cystadenocarcinoma, Mucinous/metabolism
- Cystadenocarcinoma, Mucinous/pathology
- Cystadenocarcinoma, Serous/genetics
- Cystadenocarcinoma, Serous/metabolism
- Cystadenocarcinoma, Serous/pathology
- DNA-Binding Proteins/metabolism
- Estrogen Receptor alpha/metabolism
- Estrogen Receptor beta/metabolism
- Female
- Granulosa Cell Tumor/genetics
- Granulosa Cell Tumor/metabolism
- Granulosa Cell Tumor/pathology
- Histone Acetyltransferases
- Humans
- Inhibins/blood
- Middle Aged
- Neoplasms, Glandular and Epithelial/genetics
- Neoplasms, Glandular and Epithelial/metabolism
- Neoplasms, Glandular and Epithelial/pathology
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Nuclear Receptor Co-Repressor 1
- Nuclear Receptor Co-Repressor 2
- Nuclear Receptor Coactivator 1
- Nuclear Receptor Coactivator 2
- Nuclear Receptor Coactivator 3
- Oncogene Proteins
- Ovary/cytology
- Ovary/metabolism
- RNA, Long Noncoding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Stromal Cells/cytology
- Stromal Cells/metabolism
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
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Affiliation(s)
- S Hussein-Fikret
- Prince Henry's Institute of Medical Research, PO Box 5152, Clayton, Vic. 3168, Australia; Monash University Department of Medicine, Monash Medical Centre, Clayton, Vic. 3168, Australia
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15
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Charlier TD, Balthazart J. Modulation of Hormonal Signaling in the Brain by Steroid Receptor Coactivators. Rev Neurosci 2005; 16:339-57. [PMID: 16519010 DOI: 10.1515/revneuro.2005.16.4.339] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Nuclear receptors, such as estrogen, glucocorticoid or thyroid hormone receptors, have been shown to play a critical role in brain development and physiology. The activity of these receptors is modulated by the interaction with several proteins and, in particular, coactivators are required to enhance their transcriptional activity. The steroid receptor coactivators (SRC-1, -2 and -3) are currently the best characterized coactivators and we review here the current knowledge on the distribution and function of these proteins in the brain. Knock-out models and antisense techniques have demonstrated the requirement for SRC-1 and -2 in the brain, focusing mainly on steroid and thyroid hormone-dependent development and behavior. The precise function of SRC-3 in the brain is currently unknown but its presence throughout the brain suggests an important function. Although the molecular biology of SRCs is relatively well known, the in vivo control of their expression, post-translational modifications and time- and cell-specific interactions with the different nuclear receptors remain elusive. A complete understanding of hormone action on brain and behavior will not be attained until a better knowledge of coactivator physiology is achieved.
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Affiliation(s)
- Thierry D Charlier
- University of Liège, Center for Cellular and Molecular Neurobiology, Research Group in Behavioral Neuroendocrinology, Belgium.
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16
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Zhao X, Patton JR, Davis SL, Florence B, Ames SJ, Spanjaard RA. Regulation of nuclear receptor activity by a pseudouridine synthase through posttranscriptional modification of steroid receptor RNA activator. Mol Cell 2004; 15:549-58. [PMID: 15327771 DOI: 10.1016/j.molcel.2004.06.044] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2004] [Revised: 06/08/2004] [Accepted: 06/17/2004] [Indexed: 11/18/2022]
Abstract
Nuclear receptors (NRs) induce transcription through association with coactivator complexes. We identified a pseudouridine synthase (PUS), mPus1p, as a coactivator for retinoic acid receptor (mRAR)gamma and other NR-dependent transactivation. mPus1p is a member of the truA subfamily of PUSs, a class of enzymes that isomerize uridine to pseudouridine in noncoding RNAs, such as tRNA, to ensure proper folding and function. mPus1p binds the first zinc finger of mRARgamma and also associates with other NRs. Interestingly, mPus1p pseudouridylates coactivator Steroid Receptor RNA Activator (SRA), and when coexpressed, mPus1p and SRA cooperatively enhance mRARgamma-mediated transcription. mPus1p, mRARgamma, and SRA exist in a retinoid-independent, promoter bound complex in the nucleus although mPus1p is also expressed in the nucleolus, where it likely modifies tRNA. Finally, we show that mPus1p-coactivator function required SRA, mPus1p-associated mRARgamma binding, and PUS activities. mPus1p-dependent pseudouridylation of SRA represents an additional type of posttranscriptional modification of a NR-coactivator complex that is important for NR signaling.
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MESH Headings
- Animals
- Cell Line, Tumor
- Humans
- Hydro-Lyases/genetics
- Hydro-Lyases/metabolism
- Macromolecular Substances
- Mice
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- Pseudouridine/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Long Noncoding
- RNA, Untranslated/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Signal Transduction/physiology
- Transcription, Genetic
- Transcriptional Activation
- Two-Hybrid System Techniques
- Retinoic Acid Receptor gamma
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Affiliation(s)
- Xiansi Zhao
- Department of Otolaryngology, Boston University School of Medicine, Boston, MA 02118, USA
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17
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Huang SM, Cheng YS. Analysis of two CBP (cAMP-response-element-binding protein-binding protein) interacting sites in GRIP1 (glucocorticoid-receptor-interacting protein), and their importance for the function of GRIP1. Biochem J 2004; 382:111-9. [PMID: 15137909 PMCID: PMC1133921 DOI: 10.1042/bj20040206] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Revised: 04/05/2004] [Accepted: 05/12/2004] [Indexed: 11/17/2022]
Abstract
The p160 co-activators, SRC1 (steroid receptor co-activator 1), GRIP1 (glucocorticoid-receptor-interacting protein 1) and ACTR (activator for thyroid hormone and retinoid receptors), have two ADs (activation domains), AD1 and AD2. AD1 is a binding site for the related co-activators, CBP (cAMP-response-element-binding protein-binding protein) and p300, whereas AD2 binds to another co-activator, co-activator-associated arginine methyltransferase 1 (CARM1). Here, we identified two CBP-interacting sites [amino acids 1075-1083 (site I) and 1095-1106 (site II)] in a so-called CBP-dependent transactivation domain (AD1; amino acids 1057-1109) of GRIP1. Site I was the major site for CBP-dependent AD1 transactivation activity of GRIP1 whereas, following the deletion of site II, full or partial transactivation activity was retained without the recruitment of CBP in yeast, HeLa, human embryonic kidney 293 and CV-1 cells. GRIP1 (with a deletion of site II) expressed stronger co-activator activity than that of wild-type GRIP1 in the TR (thyroid receptor) and the AR (androgen receptor), but not the ER (oestrogen receptor), systems in HeLa cells. We also demonstrated that these CBP-binding sites of GRIP1 are not the only functional domains for its AD1 function in TR, AR and ER systems in HeLa cells by the exogenous overexpression of one E1A mutant, which led to a lack of CBP-binding ability. Our results suggest that these two CBP-interacting sites in the GRIP AD1 domain not only determine its AD1 activity, but are also involved in its co-activator functions in some nuclear receptors.
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Key Words
- camp-responsive-element-binding-protein-binding protein (cbp)
- co-activator
- e1a
- glucocorticoid-receptor-interacting protein 1 (grip1)
- interacting site
- nuclear receptor
- actr, activator for thyroid hormone and retinoid receptors
- ad, activation domain
- af, activation function
- ar, androgen receptor
- β-gal, β-galactosidase
- carm1, co-activator-associated arginine methyltransferase 1
- cbp, camp-responsive-element-binding protein-binding protein
- dbd, dna-binding domain
- er, oestrogen receptor
- gr, glucocorticoid receptor
- grip1, glucocorticoid-receptor-interacting protein 1
- gst, glutathione s-transferase
- hbd, hormone-binding domain
- hek, human embryonic kidney
- lbd, ligand-binding domain
- luc, luciferase
- mmtv, murine-mammary-tumour virus
- nr, nuclear receptor
- p/caf, p300/cbp-associated factor
- pr, progesterone receptor
- src1, steroid receptor co-activator-1
- tif2, transcriptional mediator/intermediary factor 2
- tr, thyroid receptor
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Affiliation(s)
- Shih-Ming Huang
- Biochemistry Department, National Defense Medical Center, Taipei, Taiwan 114, Republic of China.
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18
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Zhang A, Yeung PL, Li CW, Tsai SC, Dinh GK, Wu X, Li H, Chen JD. Identification of a novel family of ankyrin repeats containing cofactors for p160 nuclear receptor coactivators. J Biol Chem 2004; 279:33799-805. [PMID: 15184363 DOI: 10.1074/jbc.m403997200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the p160 nuclear receptor coactivators interact with liganded nuclear receptors to enhance transcription of target genes. Here we identify a novel family of ankyrin repeats containing cofactors (ANCOs) that interact with the p160 coactivators. ANCO-1 binds to the conserved Per-Arnt-Sim (PAS) region of the p160 coactivators. It encodes a large nuclear protein with five ankyrin repeats, and parts of its sequences have been reported as nasopharyngeal carcinoma susceptibility protein and medulloblastoma antigen. Immunofluorescence staining reveals discrete nuclear foci of ANCO-1 that are distinct from known nuclear structures. Intriguingly, ANCO-1 also colocalizes and interacts with histone deacetylases. Transient reporter gene assay shows that ANCO-1 expression inhibits ligand-dependent transactivation by both steroid and nonsteroid nuclear receptors. Taken together, we have identified a novel family of ankyrin repeats containing cofactors that may recruit histone deacetylases to the p160 coactivators/nuclear receptor complex to inhibit ligand-dependent transactivation.
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Affiliation(s)
- Aihua Zhang
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA
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19
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Smith CL, O'Malley BW. Coregulator function: a key to understanding tissue specificity of selective receptor modulators. Endocr Rev 2004; 25:45-71. [PMID: 14769827 DOI: 10.1210/er.2003-0023] [Citation(s) in RCA: 640] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Ligands for the nuclear receptor superfamily control many aspects of biology, including development, reproduction, and homeostasis, through regulation of the transcriptional activity of their cognate receptors. Selective receptor modulators (SRMs) are receptor ligands that exhibit agonistic or antagonistic biocharacter in a cell- and tissue context-dependent manner. The prototypical SRM is tamoxifen, which as a selective estrogen receptor modulator, can activate or inhibit estrogen receptor action. SRM-induced alterations in the conformation of the ligand-binding domains of nuclear receptors influence their abilities to interact with other proteins, such as coactivators and corepressors. It has been postulated, therefore, that the relative balance of coactivator and corepressor expression within a given target cell determines the relative agonist vs. antagonist activity of SRMs. However, recent evidence reveals that the cellular environment also plays a critical role in determining SRM biocharacter. Cellular signaling influences the activity and subcellular localization of coactivators and corepressors as well as nuclear receptors, and this contributes to gene-, cell-, and tissue-specific responses to SRM ligands. Increased understanding of the effect of cellular environment on nuclear receptors and their coregulators has the potential to open the field of SRM discovery and research to many members of the nuclear receptor superfamily.
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Affiliation(s)
- Carolyn L Smith
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
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20
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Brown K, Chen Y, Underhill TM, Mymryk JS, Torchia J. The coactivator p/CIP/SRC-3 facilitates retinoic acid receptor signaling via recruitment of GCN5. J Biol Chem 2003; 278:39402-12. [PMID: 12885766 DOI: 10.1074/jbc.m307832200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
p/CIP/SRC-3 is a member of a family of steroid receptor coactivators/nuclear receptor coactivators (SRC/NCoA) proteins that mediate the transcriptional effects of nuclear hormone receptors (NRs). Using deletion analysis we have mapped the location of two distinct activation domains in p/CIP (AD1 and AD2) capable of activating transcription in mammalian cells when fused to the Gal4-DNA binding domain. In addition to AD1 being coincident with the interaction domain for CBP, we demonstrate a novel in vivo interaction between the AD1 and GCN5. Overexpression of a Gal4-AD1 fusion protein in yeast leads to growth arrest that is relieved by mutation of genes encoding components of the SAGA complex including GCN5, ADA3, and SPT7. In addition, the AD1 of p/CIP and the ADA3 gene are shown to be essential for retinoic acid receptor alpha-dependent transcription in yeast. Transient transfection assays in mammalian cells indicate that GCN5 cooperates with p/CIP as a coactivator of RAR alpha-dependent transcription. Down-regulation of GCN5 using small interfering RNA in mammalian cells indicates that the AD1 domain and the RAR beta promoter activity are dependent, in part, on GCN5. Mutational analysis of AD1 has identified two helical motifs that are required for interactions with GCN5 and CBP. Taken together, these results support a model by which p/CIP functions as a ligand-dependent adapter, through specific protein-protein interactions with AD1, to recruit members from at least two distinct families of acetyltransferase proteins to NRs.
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Affiliation(s)
- Kirk Brown
- Department of Oncology, University of Western Ontario and the London Regional Cancer Centre, London, Ontario N6A 4L6, Canada
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21
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Xu J, Li Q. Review of the in vivo functions of the p160 steroid receptor coactivator family. Mol Endocrinol 2003; 17:1681-92. [PMID: 12805412 DOI: 10.1210/me.2003-0116] [Citation(s) in RCA: 355] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The p160 steroid receptor coactivator (SRC) gene family contains three homologous members, which serve as transcriptional coactivators for nuclear receptors and certain other transcription factors. These coactivators interact with ligand-bound nuclear receptors to recruit histone acetyltransferases and methyltransferases to specific enhancer/promotor regions, which facilitates chromatin remodeling, assembly of general transcription factors, and transcription of target genes. This minireview summarizes our current knowledge about the molecular structures, molecular mechanisms, temporal and spatial expression patterns, and biological functions of the SRC family. In particular, this article highlights the roles of SRC-1 (NCoA-1), SRC-2 (GRIP1, TIF2, or NCoA-2) and SRC-3 (p/CIP, RAC3, ACTR, AIB1, or TRAM-1) in development, organ function, endocrine regulation, and nuclear receptor function, which are defined by characterization of the genetically manipulated animal models. Furthermore, this article also reviews our current understanding of the role of SRC-3 in breast cancer and discusses possible mechanisms for functional specificity and redundancy among SRC family members.
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Affiliation(s)
- Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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22
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Dutertre M, Smith CL. Ligand-independent interactions of p160/steroid receptor coactivators and CREB-binding protein (CBP) with estrogen receptor-alpha: regulation by phosphorylation sites in the A/B region depends on other receptor domains. Mol Endocrinol 2003; 17:1296-314. [PMID: 12714702 DOI: 10.1210/me.2001-0316] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Estrogen receptor (ER)alpha and ERbeta are transcription factors that can be activated by both ligand binding and growth factor signaling. Estradiol increases ER activity in part by enhancing interactions between its carboxy-terminal, ligand-binding domain (LBD) and the p160/SRC (steroid receptor coactivator) and p300/CBP (cAMP response element binding protein (CREB) binding protein) families of coactivators. In the absence of ligand and the LBD, these cofactors can also interact with the amino-terminal (A/B) domain of ERs in vitro. SRC-1 also enhances the ligand-independent activity of the full-length receptor. Both ligand-independent and estradiol-induced ER activity are increased by phosphorylation at specific serine (Ser) residues in the A/B domain (Ser104/106 and Ser118 in ERalpha). In the case of ERbeta, phosphorylation enhances the ligand-independent recruitment and action of SRC-1. We show here that unliganded ERalpha can activate endogenous gene expression in MCF-7 cells, and that this activation is mediated in part by a p160 coactivator. In transfected HeLa cells, we show that the full-length ERalpha can interact physically and functionally with p160/SRCs and CBP in the absence of ligand and that mutation of Ser104/106/118 affects these interactions. Accordingly, ERalpha dephosphorylation decreases its ligand-independent interaction with SRC-1 and CBP in vitro. In HeLa cells, both Ser104/106 and Ser118 impinge on SRC-1 action by two mechanisms: 1) a seemingly indirect effect on SRC-1 recruitment that requires other receptor domains in addition to the A/B, consistent with our finding that the ligand-independent interaction between the A/B and the LBD and its enhancement by SRC-1 depend in part on Ser104/106/118; and 2) an effect on SRC-1 coactivation that can be observed in the absence of the LBD. Ser104/106/118 can also affect coactivation by a subset of coactivators in the presence of hormone, albeit to a lesser extent than in its absence. Altogether, our observations suggest that the enhancement of ERalpha activity by p160/SRCs and CBP can be regulated by phosphorylation and stress the importance of using full-length receptors to assess the role of the activation function-1 in cofactor recruitment.
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Affiliation(s)
- Martin Dutertre
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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23
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Callewaert L, Verrijdt G, Christiaens V, Haelens A, Claessens F. Dual function of an amino-terminal amphipatic helix in androgen receptor-mediated transactivation through specific and nonspecific response elements. J Biol Chem 2003; 278:8212-8. [PMID: 12509416 DOI: 10.1074/jbc.m210744200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Steroid receptors are transcription factors that, upon binding to their response elements, regulate the expression of several target genes via direct protein interactions with transcriptional coactivators. For the androgen receptor, additional interactions between the amino- and carboxyl-terminal regions have been reported. The first amino acids of the amino-terminal domain are necessary for this amino/carboxyl-terminal interaction. Deletion of a FQNLF core sequence in this region blunts the interaction, as does a G21E mutation. We investigated the effect of the aforementioned mutations in the context of the full size androgen receptor on a series of selective and nonselective androgen response elements. Strikingly, the FQNLF deletion strongly reduced the androgen receptor capacity to transactivate through nonselective motifs but did not affect its activity on selective elements. Although the G21E mutation strongly impairs the amino/carboxyl-terminal interaction, it does not significantly influence androgen receptor activity on either selective or nonselective elements. Surprisingly, this mutation leads to an increased binding of the amino-terminal domain to the glutamine-rich region of the steroid receptor coactivator-1 of the p160 family. Taken together, these data suggest that the amino-terminal amino acids of the androgen receptor play a key role in determining its transcriptional activity by modulating the interaction with the ligand-binding domain as well as interaction with p160 coactivators.
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Affiliation(s)
- Leen Callewaert
- Division of Biochemistry, Faculty of Medicine, Campus Gasthuisberg, University of Leuven, Herestraat 49, Belgium
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24
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van Wely KHM, Molijn AC, Buijs A, Meester-Smoor MA, Aarnoudse AJ, Hellemons A, den Besten P, Grosveld GC, Zwarthoff EC. The MN1 oncoprotein synergizes with coactivators RAC3 and p300 in RAR-RXR-mediated transcription. Oncogene 2003; 22:699-709. [PMID: 12569362 DOI: 10.1038/sj.onc.1206124] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The t(12;22) creates an MN1-TEL fusion gene leading to acute myeloid leukemia. The fusion partner TEL (ETV6) is a member of the ETS family of transcription factors. The nature of the other fusion partner, MN1, has not been investigated in detail until now. We recently described that MN1 activates the transcription activity of the moloney sarcoma virus long terminal repeat, indicating that this protein itself may act as a transcription factor. We show here that MN1 comprises multiple transcription activating domains. A search for a bound DNA sequence revealed that MN1 has affinity for retinoic acid responsive elements. A DR5 retinoic acid responsive element was observed in the LTR. The combination of MN1 and ligand-activated retinoic acid receptor leads to a synergistic induction of expression directed by the LTR. Cotransfection of MN1 with RAC3 or p300, known coactivators of retinoic acid receptors, leads to a further synergistic induction of transcription. In addition, the effect of MN1 can be inhibited by the wild-type adenovirus ElA protein that inhibits p300 function, but not by an E1A mutant lacking the p300-binding site. GAL4-MN1-mediated transcription can be enhanced directly by RAC3 and p300. Taken together, our results indicate that MN1 is a transcription coactivator rather than a sequence-specific transcription factor, and that it may stimulate RAR/RXR-mediated transcription through interaction with p160 and p300.
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25
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Liao L, Kuang SQ, Yuan Y, Gonzalez SM, O'Malley BW, Xu J. Molecular structure and biological function of the cancer-amplified nuclear receptor coactivator SRC-3/AIB1. J Steroid Biochem Mol Biol 2002; 83:3-14. [PMID: 12650696 DOI: 10.1016/s0960-0760(02)00254-6] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Nuclear hormone receptors are ligand-dependent transcription factors that require coactivators to regulate target gene expression. The steroid receptor coactivator-3 (SRC-3), also known as p/CIP, RAC3, AIB1, ACTR and TRAM-1, is a cancer-amplified coactivator in the SRC gene family that also contains SRC-1 and TIF2/GRIP1. SRC-3 interacts with nuclear receptors and certain other transcription factors, recruits histone acetyltransferases and methyltransferases for chromatin remodeling and facilitates target gene transcription. Accumulated results from both ex vivo and animal model studies indicate that SRC-3 plays important roles in many biological processes involving cell proliferation, cell migration, cell differentiation, somatic growth, sexual maturation, female reproductive function, vasoprotection and breast cancer. This article summarizes our current knowledge about SRC-3 under the following topics: molecular cloning and characterization; molecular structure and functional mechanisms; SRC-3 as a molecular target of growth factors and cytokines; organization and expression of the SRC-3 gene; generation and characterization of SRC-3 knockout mice; role of SRC-3 in the vasoprotective effects of estrogen; role of SRC-3 in cell migration, proliferation and cancers.
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Affiliation(s)
- Lan Liao
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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26
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Lauritsen KJ, List HJ, Reiter R, Wellstein A, Riegel AT. A role for TGF-beta in estrogen and retinoid mediated regulation of the nuclear receptor coactivator AIB1 in MCF-7 breast cancer cells. Oncogene 2002; 21:7147-55. [PMID: 12370804 DOI: 10.1038/sj.onc.1205943] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2002] [Revised: 07/31/2002] [Accepted: 08/07/2002] [Indexed: 11/08/2022]
Abstract
AIB1 (amplified in breast cancer 1) is a nuclear receptor coactivator gene amplified and overexpressed in breast cancer. However, the mechanisms by which AIB1 is regulated are unclear. Here we show that 17beta-estradiol represses AIB1 mRNA and protein expression in MCF-7 human breast cancer cells primarily by suppressing AIB1 gene transcription. Estrogen levels present in fetal calf serum are sufficient to maintain AIB1 mRNA and protein at low basal levels, and this repression is reversed by the addition of antiestrogens or all-trans retinoic acid. Interestingly, cycloheximide inhibition experiments revealed that secondary protein synthesis was necessary to induce AIB1 expression by antiestrogens and retinoids. Experiments with TGF-beta and TGF-beta blocking antibodies demonstrated that this growth factor modulates AIB1 expression and showed that the antiestrogen and retinoid induction of AIB1 gene expression is mediated at least in part through TGF-beta. These data reveal a mechanism of estrogen-induced down-modulation of the overall hormone sensitivity of cells through feedback inhibition of coactivator gene expression. These data also suggest that antiestrogens can shift the sensitivity of cells to non-estrogenic proliferative signaling by increasing cellular levels of AIB1. This effect may play a role in breast cancer progression and resistance to drug treatment.
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Affiliation(s)
- Kristina J Lauritsen
- Department of Oncology, Vincent T Lombardi Cancer Center, Research Building, E307, Georgetown University, 3970 Reservoir Road, Washington, DC 20007, USA
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27
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Xu J, O'Malley BW. Molecular mechanisms and cellular biology of the steroid receptor coactivator (SRC) family in steroid receptor function. Rev Endocr Metab Disord 2002; 3:185-92. [PMID: 12215713 DOI: 10.1023/a:1020016208071] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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Fu M, Wang C, Wang J, Zafonte BT, Lisanti MP, Pestell RG. Acetylation in hormone signaling and the cell cycle. Cytokine Growth Factor Rev 2002; 13:259-76. [PMID: 12486878 DOI: 10.1016/s1359-6101(02)00003-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The last decade has seen a substantial change in thinking about the role of acetylation in regulating diverse cellular processes. The correlation between histone acetylation and gene transcription has been known for many years. The cloning and biochemical characterization of the enzymes that regulate this post-translational modification has led to an understanding of the diverse role histone acetyltransferases (HATs) play in cellular function. Histone acetylases modify histones, transcription factors, co-activators, nuclear transport proteins, structural proteins and components of the cell cycle. This review focuses on the role of histone acetylases in coordinating hormone signaling and the cell cycle. Transition through the cell cycle is regulated by a family of protein kinase holoenzymes, the cyclin-dependent kinases (Cdks) and their heterodimeric cyclin partners. Recent studies have identified important cross-talk between the cell cycle regulatory apparatus and proteins regulating histone acetylation. The evidence for a dynamic interplay between components regulating the cell cycle and acetylation of target substrates provides an important new level of complexity in the mechanisms governing hormone signaling.
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Affiliation(s)
- Maofu Fu
- Division of Hormone-Dependent Tumor Biology, Albert Einstein Comprehensive Cancer Center, Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Chanin 302, 1300 Morris Park Ave, Bronx, NY 10461, USA
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29
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Kurihara I, Shibata H, Suzuki T, Ando T, Kobayashi S, Hayashi M, Saito I, Saruta T. Expression and regulation of nuclear receptor coactivators in glucocorticoid action. Mol Cell Endocrinol 2002; 189:181-9. [PMID: 12039076 DOI: 10.1016/s0303-7207(01)00717-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nuclear receptor coactivators are involved in receptor-mediated transcriptional activation of target genes in a hormone-sensitive manner, and the mechanism of their transactivation has been studied in recent years. The glucocorticoid receptor (GR) interacts with several coactivators, including steroid receptor coactivator-1 (SRC-1) family and CREB-binding protein (CBP). Since coactivators function as transcription amplifiers, subtle changes in expression levels of coactivators in certain cells would markedly intensify receptor-mediated transcriptional activity. The regulation of coactivators by glucocorticoid action, however, has not yet been clarified. In this study, we have shown that one of the coactivators interacting with GR, SRC-1, is downregulated by dexamethasone (DEX) both in vivo and in vitro. In experiments on Sprague-Dawley rats in vivo, the downregulation of SRC-1 was observed in heart, stomach, kidney, liver, and cerebrum, and in experiments on two types of kidney-derived cells in vitro, similar downregulation of SRC-1 was demonstrated in both types of cells. DEX-mediated downregulation of SRC-1 mRNA recovered in 4-8 h, while the downregulation of SRC-1 protein lasted for 12 h and its levels returned to the basal level, 24 h after DEX treatment. Other coactivators examined in this study showed no remarkable changes in expression by DEX treatment, implying that ligand-mediated downregulation of SRC-1 has a pivotal role in the physiology of glucocorticoid action.
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Affiliation(s)
- Isao Kurihara
- Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, 160-8582, Tokyo, Japan
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Cavarretta ITR, Mukopadhyay R, Lonard DM, Cowsert LM, Bennett CF, O'Malley BW, Smith CL. Reduction of coactivator expression by antisense oligodeoxynucleotides inhibits ERalpha transcriptional activity and MCF-7 proliferation. Mol Endocrinol 2002; 16:253-70. [PMID: 11818499 DOI: 10.1210/mend.16.2.0770] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Steroid receptor RNA activator (SRA) is a novel coactivator for steroid receptors that acts as an RNA molecule, whereas steroid receptor coactivator (SRC) family members, such as steroid receptor coactivator-1 (SRC-1) and transcriptional intermediary factor 2 (TIF2) exert their biological effects as proteins. Individual overexpression of each of these coactivators, which can form multimeric complexes in vivo, results in stimulated ERalpha transcriptional activity in transient transfection assays. However there is no information on the consequences of reducing SRC-1, TIF2, or SRA expression, singly or in combination, on ERalpha transcriptional activity. We therefore developed antisense oligodeoxynucleotides (asODNs) to SRA, SRC-1, and TIF2 mRNAs, which rapidly and specifically reduced the expression of each of these coactivators. ERalpha-dependent gene expression was reduced in a dose-dependent fashion by up to 80% in cells transfected with these oligonucleotides. Furthermore, treatment of cells with combinations of SRA, SRC-1, and TIF2 asODNs reduced ERalpha transcriptional activity to an extent greater than individual asODN treatment alone, suggesting that these coactivators cooperate, in at least an additive fashion, to activate ERalpha-dependent target gene expression. Finally, treatment of MCF-7 cells with asODN against SRC-1 and TIF2 revealed a requirement of these coactivators, but not SRA, for hormone-dependent DNA synthesis and induction of estrogen-dependent pS2 gene expression, indicating that SRA and SRC family coactivators can fulfill specific functional roles. Taken together, we have developed a rapid method to reduce endogenous coactivator expression that enables an assessment of the in vivo role of specific coactivators on ERalpha biological action and avoids potential artifacts arising from overexpression of coactivators in transient transfection assays.
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MESH Headings
- Blotting, Western
- Cell Division/drug effects
- Down-Regulation/drug effects
- Estrogen Receptor alpha
- Estrogens/metabolism
- Estrogens/pharmacology
- Gene Expression Regulation/drug effects
- HeLa Cells
- Histone Acetyltransferases
- Humans
- Nuclear Receptor Coactivator 1
- Nuclear Receptor Coactivator 2
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/pharmacology
- RNA, Long Noncoding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- Receptors, Estrogen/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Substrate Specificity
- Time Factors
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic/drug effects
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- Ilaria T R Cavarretta
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030-3498, USA
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31
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Gnanapragasam VJ, Leung HY, Pulimood AS, Neal DE, Robson CN. Expression of RAC 3, a steroid hormone receptor co-activator in prostate cancer. Br J Cancer 2001; 85:1928-36. [PMID: 11747336 PMCID: PMC2364015 DOI: 10.1054/bjoc.2001.2179] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RAC 3, one of the p160 family of co-activators is known to enhance the transcriptional activity of a number of steroid receptors. As co-activators are also known to enhance androgen receptor (AR) activity, we investigated the role of RAC 3 in the context of prostate cancer. In prostate cancer cell lines, we found variable levels of the RAC 3 protein with highest expression seen in AR-positive LNCaP cells, moderate expression in AR-negative PC 3 cells and low-level expression in AR-negative DU 145 cells. Immuno-precipitation studies showed that endogenous RAC 3 interacted with the AR in vivo and transfection assays confirmed that RAC 3 enhanced AR transcriptional activity. In clinical prostate tissue, we found strong RAC 3 mRNA expression and immuno-histochemistry demonstrated that in benign tissue, the protein was expressed predominantly in luminal cells, while in primary malignant epithelium it was more homogeneously expressed. In a series of 37 patients, the levels of RAC 3 expression correlated significantly with tumour grade (P = 0.01) and stage of disease (P = 0.03) but not with serum PSA levels. In addition moderate or high RAC 3 expression was associated with poorer disease-specific survival (P = 0.03). We conclude that RAC 3 is an important co-activator of the AR in the prostate and may have an important role in the progression of prostate cancer.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Aged
- Aged, 80 and over
- Androgens
- Biomarkers, Tumor/blood
- Disease Progression
- Epithelial Cells/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- In Situ Hybridization
- Male
- Middle Aged
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Staging
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/metabolism
- Neoplasms, Hormone-Dependent/pathology
- Nuclear Receptor Coactivator 3
- Prostate-Specific Antigen/blood
- Prostatic Hyperplasia/metabolism
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/genetics
- Receptors, Androgen/metabolism
- Trans-Activators/biosynthesis
- Trans-Activators/genetics
- Transcription Factors
- Transcription, Genetic
- Transfection
- Tumor Cells, Cultured/metabolism
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Affiliation(s)
- V J Gnanapragasam
- Prostate Research Group, School of Surgical Sciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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32
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Azorsa DO, Cunliffe HE, Meltzer PS. Association of steroid receptor coactivator AIB1 with estrogen receptor-alpha in breast cancer cells. Breast Cancer Res Treat 2001; 70:89-101. [PMID: 11768608 DOI: 10.1023/a:1012972808558] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The steroid receptor coactivator AIB1 (amplified in breast cancer-1) is a transcriptional coactivator which has been found to be amplified in breast cancer. We have now investigated the role of the AIB1 protein in breast cancer cell lines. Although detectable levels of AIB1 were present in most cell lines, high levels of AIB1 expression were observed only in the ER-positive cell lines MCF-7 and BT-474 by western blot analysis. Newly developed monoclonal antibodies (mAbs) were used in several assays to show an association between AIBI and estrogen receptor-alpha (ER). AIB1 and ER co-localized to the nucleus of ER positive cell lines as shown by immunofluorescence microscopy, and a functional association of native AIB1 and ER in MCF-7 nuclear extracts was shown by EMSA. Recombinant ER also recruited AIB1 protein from nuclear extracts, shown by EMSA and by precipitation of ER-complex proteins bound to a biotinylated-ERE DNA target. Additionally, anti-AIB1 mAbs were able to immunoprecipitate ER from nuclear extracts of chemically cross-linked cells but not from uncross-linked cells. Both immunoprecipitation and oligonucleotide precipitation studies demonstrated the presence of p300 and CBP as part of the ER transcriptional complex. These results suggest that AIB1 and ER do associate physically in ER-positive breast cancer cell lines. We propose that in AIB1 amplified breast cancers, a heightened AIB1/ER association may play a crucial role in the progression of these tumors.
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Affiliation(s)
- D O Azorsa
- Cancer Genetics Branch, National Human Genome Research Institute, The National Institutes of Health, Bethesda, MD 20892-4470, USA
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33
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Kim MY, Hsiao SJ, Kraus WL. A role for coactivators and histone acetylation in estrogen receptor alpha-mediated transcription initiation. EMBO J 2001; 20:6084-94. [PMID: 11689448 PMCID: PMC125694 DOI: 10.1093/emboj/20.21.6084] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transcriptional regulation by estrogen receptor alpha (ERalpha) involves protein-protein interactions among the receptor, its associated coactivators and the RNA polymerase II transcriptional machinery. We have used an in vitro chromatin assembly and transcription system to examine the biochemistry of interactions among ERalpha, the SRC proteins and p300/CBP. Using polypeptides designed to block specific receptor- cofactor or cofactor-cofactor interactions, we show that interactions among ERalpha, its coactivators and the RNA pol II machinery are all required for ERalpha- mediated transcription. Furthermore, we show that ERalpha-SRC-p300/CBP interactions are necessary and sufficient for the targeted acetylation of nucleosomal histones on estrogen-responsive promoters in the absence of transcription. The protein-protein interactions required for histone acetylation constitute a subset of the interactions required for transcriptional activation. Finally, we show that the major role of SRC-p300/CBP interactions is to enhance ERalpha- mediated transcription initiation, and they have little or no role in stimulating subsequent rounds of transcription. Together, our results indicate a specific role for the SRC and p300/CBP coactivators, as well as targeted histone acetylation, in ERalpha-mediated transcription.
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Affiliation(s)
- M Y Kim
- Department of Molecular Biology and Genetics, Graduate Field of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
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34
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Kerley JS, Olsen SL, Freemantle SJ, Spinella MJ. Transcriptional activation of the nuclear receptor corepressor RIP140 by retinoic acid: a potential negative-feedback regulatory mechanism. Biochem Biophys Res Commun 2001; 285:969-75. [PMID: 11467847 DOI: 10.1006/bbrc.2001.5274] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Through the use of microarray analysis it was discovered that the nuclear receptor coregulator, receptor interacting protein 140 (RIP140), was induced early during all-trans retinoic acid (RA)-induced differentiation of human embryonal carcinoma cells. A rapid, fourfold induction of RIP140 mRNA was detected within 3 h of RA treatment in human embryonal carcinoma and MCF-7 human breast cancer cells. RIP140 protein levels were induced within 6 h of RA treatment. The RA induction of RIP140 mRNA did not require de novo protein synthesis, consistent with RIP140 being a direct transcriptional target of retinoid receptors. Promoter/enhancer elements directly upstream of the RIP140 coding region supported RA-induced transcription of a luciferase gene. In addition the ability of overexpressed RIP140 to repress ligand activated retinoid receptors was confirmed. The finding that RIP140 is a direct transcriptional target of RA is one of the first examples of acute transcriptional regulation of a nuclear receptor coactivator or corepressor. These data are consistent with a model by which RA induction of RIP140 supplies a negative feedback signal toward ligand-activated retinoid receptors.
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Affiliation(s)
- J S Kerley
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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35
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Abstract
The actions of lipophilic hormones, including steroids, retinoids, thyroid hormone and vitamin D(3), are mediated through a conserved superfamily of nuclear receptor proteins that function as ligand-regulated, DNA-binding transcriptional activators in the chromatin environment of the nucleus. The ligand-dependent transcriptional activity of nuclear receptors is enhanced by various cofactors that remodel chromatin, acetylate nucleosomal histones and contact the basal transcriptional machinery. The current challenge is to understand the mechanistic details of how interactions among these factors enhance transcription of hormone-regulated genes assembled into chromatin. Current biochemical and cell-based methods are providing some important clues.
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Affiliation(s)
- K C Lee
- Dept of Molecular Biology and Genetics, Cornell University, 14853, Ithaca, NY, USA
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36
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Abstract
There was a time when the classification of sex hormones was simple. Androgens were male and estrogens female. What remains true today is that in young adults androgen levels are higher in males and estrogen levels higher in females. More recently we have learned that estrogens are necessary in males for regulation of male sexual behavior, maintenance of the skeleton and the cardiovascular system, and for normal function of the testis and prostate. The importance of androgen in females was never in doubt, it is after all the precursor of estrogen as the substrate for aromatase, the enzyme that produces estrogen. In addition, the tissue distribution of androgen receptors suggests that androgens themselves are important in the ovary, uterus, breast, and brain. New information promises to clarify some of the complex issues of the physiological roles of estrogen and the contribution of estrogen to the development of neoplastic diseases in humans. The discovery of the second estrogen receptor, the creation of mutant mice defective in both estrogen receptors and in the aromatase gene, the solution of the structures of the ligand-binding domains of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta), the finding of novel routes through which estrogen receptors can modulate transcription, and the identification of a man with a bi-allelic disruptive mutation of the ERalpha gene are but some of the milestones. This review focuses on the mechanistic aspects of signal transduction mediated by ERs and on the physiological consequences of deficiency of estrogen or estrogen receptor in the available mouse models.
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Affiliation(s)
- K Pettersson
- Department of Medical Nutrition and Department of Biosciences, Karolinska Institute, NOVUM, Huddinge S-141 86, Sweden
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37
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Issa LL, Leong GM, Barry JB, Sutherland RL, Eisman JA. Glucocorticoid receptor-interacting protein-1 and receptor-associated coactivator-3 differentially interact with the vitamin D receptor (VDR) and regulate VDR-retinoid X receptor transcriptional cross-talk. Endocrinology 2001; 142:1606-15. [PMID: 11250942 DOI: 10.1210/endo.142.4.8068] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The vitamin D(3) receptor (VDR) is a ubiquitously expressed nuclear hormone receptor, and its ligand, calcitriol, has diverse biological effects. The extent to which transcriptional coactivators are involved in modulating tissue-specific functions of the VDR is unclear. Hence, the current studies investigated the role of p160 coactivators in regulating VDR function and interaction with RXR. Two p160 coactivators, glucocorticoid receptor-interacting protein-1 (GRIP1) and receptor-associated coactivator-3 (RAC3), which are expressed in an inverse fashion in cell lines representative of calcitriol target tissues, interacted directly with the VDR, both in vitro and in yeast cells, but only in the presence of calcitriol. Deletional analyses of VDR indicated that GRIP1 and RAC3 required an intact VDR activation function (AF-2) domain for efficient interaction as well as additional but distinct regions of the VDR. Coexpression experiments in yeast cells indicated that both GRIP1 and RAC3 coassemble with the VDR to form an active transcriptional complex. They also form ternary complexes with VDR homodimers and VDR:RXRalpha heterodimers. In mammalian cells, GRIP1 augmented VDR activation of the osteocalcin promoter, whereas RAC3 enhanced VDR activation indirectly through RXR. These data suggest different coactivators regulate VDR function via distinct mechanisms and support the hypothesis that the VDR recruits different coactivators depending on specific gene and cellular contexts.
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Affiliation(s)
- L L Issa
- Bone and Mineral Research Program, Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, New South Wales 2010, Australia.
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38
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McKenna NJ, O'Malley BW. From ligand to response: generating diversity in nuclear receptor coregulator function. J Steroid Biochem Mol Biol 2000; 74:351-6. [PMID: 11162944 DOI: 10.1016/s0960-0760(00)00112-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear receptor ligands regulate diverse developmental and physiological processes by activating intracellular members of the nuclear receptor superfamily. Activated nuclear receptors mediate the expression of distinct gene networks in vivo by an as yet unspecified mechanism. Central to the process is the recruitment by these receptors of coactivators, a functionally diversified set of factors shown to be required for efficient transcriptional regulation by activated receptors. This article will highlight recent advances in selected mechanistic aspects of receptor function, as well as discussing the potential of coactivators to act as mediators of the intricate pharmacology of nuclear receptor ligands.
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Affiliation(s)
- N J McKenna
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, 77030, Houston, TX, USA
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39
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Kurihara I, Shibata H, Suzuki T, Ando T, Kobayashi S, Hayashi M, Saito I, Saruta T. Transcriptional regulation of steroid receptor coactivator-1 (SRC-1) in glucocorticoid action. Endocr Res 2000; 26:1033-8. [PMID: 11196413 DOI: 10.3109/07435800009048635] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diverse mechanisms of steroid receptor action have been clarified in recent years, as a consequence of the discovery of multiple coactivators. Among them, steroid receptor coactivator-1 (SRC-1) is a member of the p160 coactivator families, which are 160 kDa proteins that interact with steroid receptors in a hormone-sensitive manner. Since coactivators function as transcriptional power boosters, subtle changes in coactivator expression levels in certain cells markedly change of receptor-mediated transcriptional activity. Expression of the glucocorticoid receptor (GR) has been shown to be autoregulated in glucocorticoid action, i.e., GR is downregulated by its cognate ligand, indicating that this autoregulation of GR may protect target cells against excessive hormone action. In the present study, we examined whether coactivator expression levels are also regulated by glucocorticoids. Among several coactivators, the SRC-1 mRNA level was downregulated by dexamethasone treatment in rat tissues, such as liver, heart, kidney, stomach, and cerebrum, in vivo. We also demonstrated dexamethasone-mediated downregulation of SRC-1 mRNA and its protein levels in rat renal mesangial cells in vitro. These results suggest that ligand-mediated downregulation of SRC-1 is crucial in the physiology of glucocorticoid action.
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Affiliation(s)
- I Kurihara
- Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan
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40
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Xu J, Liao L, Ning G, Yoshida-Komiya H, Deng C, O'Malley BW. The steroid receptor coactivator SRC-3 (p/CIP/RAC3/AIB1/ACTR/TRAM-1) is required for normal growth, puberty, female reproductive function, and mammary gland development. Proc Natl Acad Sci U S A 2000; 97:6379-84. [PMID: 10823921 PMCID: PMC18611 DOI: 10.1073/pnas.120166297] [Citation(s) in RCA: 420] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Steroid receptor coactivator-3 (SRC-3) is a coactivator of nuclear receptors in the SRC family as assayed in vitro. Here, we show that mouse SRC-3 is expressed in a tissue-specific fashion and distributed mainly in the oocytes, mammary glands, hippocampus, olfactory bulb, smooth muscle, hepatocytes, and vaginal epithelium. Genetic disruption of SRC-3 in mice results in a pleiotropic phenotype showing dwarfism, delayed puberty, reduced female reproductive function, and blunted mammary gland development. Hormonal analysis indicates that SRC-3 plays a role in both the growth hormone regulatory pathway and the production of estrogen, which may explain the observed phenotypes. These results suggest that the physiological role of SRC-3 is different from that of SRC-1 and prove the diversity among coactivator family members.
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Affiliation(s)
- J Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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41
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Affiliation(s)
- C M Klinge
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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42
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Soutoglou E, Papafotiou G, Katrakili N, Talianidis I. Transcriptional activation by hepatocyte nuclear factor-1 requires synergism between multiple coactivator proteins. J Biol Chem 2000; 275:12515-20. [PMID: 10777539 DOI: 10.1074/jbc.275.17.12515] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepatocyte nuclear factor-1 (HNF-1) plays an important role in the regulation of a large number of genes expressed in the liver, kidney, and pancreatic beta-cells. In exploring the molecular mechanism involved in HNF-1-dependent gene activation in the in vivo chromatin context, we found that HNF-1 can physically interact with the histone acetyltransferases (HATs) CREB-binding protein (CBP), p300/CBP-associated factor (P/CAF), Src-1, and RAC3. The transcriptional activation potential of HNF-1 on a genome integrated promoter was strictly dependent on the synergistic action of CBP and P/CAF, which can independently interact with the N-terminal and C-terminal domain of HNF-1, respectively. Moreover, the HAT activity of both coactivators was important, as opposed to the selective requirement for the HAT activity of P/CAF in activation from a transiently transfected reporter. Interaction of CBP with the N-terminal domain of HNF-1 greatly increased the binding affinity for P/CAF with the C-terminal activation domain, which may represent the molecular basis for the observed functional synergism. The results support a model that involves the combined action of multiple coactivators recruited by HNF-1, which activate transcription by coupling nucleosome modification and recruitment of the general transcription machinery.
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Affiliation(s)
- E Soutoglou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 711 10 Herakleion Crete, Greece
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43
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The t(5;17) acute promyelocytic leukemia fusion protein NPM-RAR interacts with co-repressor and co-activator proteins and exhibits both positive and negative transcriptional properties. Blood 2000. [DOI: 10.1182/blood.v95.8.2683] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The t(5;17) variant of acute promyelocytic leukemia (APL) fuses the genes for nucleophosmin (NPM) and the retinoic acid receptor alpha (RAR). Two NPM-RAR molecules are expressed as a result of alternative RNA splicing. Both contain RAR sequences that encode the DNA binding, heterodimerization, and ligand activation domains of RAR. This study was designed to test the ability of these fusion proteins to act as transcriptional activators of retinoic acid responsive promoters. The NPM-RAR fusion proteins bind to retinoic acid response element sequences as either homodimers or as heterodimers with RXR. Transcription of retinoic acid–inducible promoters is activated by the fusion proteins in the presence of retinoic acid. The level of transactivation induced by the NPM-RAR fusions differs from the level of transactivation induced by wild-type RAR in both a promoter and cell specific fashion, and more closely parallels the pattern of activation of the PML-RAR fusion than wild-type RAR. In addition, NPM-RAR decreases basal transcription from some promoters and acts in a dominant-negative fashion when co-transfected with wild-type RAR. Both NPM-RAR and PML-RAR interact with the co-repressor protein SMRTe in a manner that is less sensitive than RAR to dissociation by retinoic acid. Retinoic acid induces binding of the co-activator protein RAC3. These data indicate that the NPM-RAR fusion proteins can modulate expression of retinoid-responsive genes in a positive or negative manner, depending on context of the promoter, and lend support to the hypothesis that aberrant transcriptional activation underlies the APL phenotype.
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44
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The t(5;17) acute promyelocytic leukemia fusion protein NPM-RAR interacts with co-repressor and co-activator proteins and exhibits both positive and negative transcriptional properties. Blood 2000. [DOI: 10.1182/blood.v95.8.2683.008k29_2683_2690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The t(5;17) variant of acute promyelocytic leukemia (APL) fuses the genes for nucleophosmin (NPM) and the retinoic acid receptor alpha (RAR). Two NPM-RAR molecules are expressed as a result of alternative RNA splicing. Both contain RAR sequences that encode the DNA binding, heterodimerization, and ligand activation domains of RAR. This study was designed to test the ability of these fusion proteins to act as transcriptional activators of retinoic acid responsive promoters. The NPM-RAR fusion proteins bind to retinoic acid response element sequences as either homodimers or as heterodimers with RXR. Transcription of retinoic acid–inducible promoters is activated by the fusion proteins in the presence of retinoic acid. The level of transactivation induced by the NPM-RAR fusions differs from the level of transactivation induced by wild-type RAR in both a promoter and cell specific fashion, and more closely parallels the pattern of activation of the PML-RAR fusion than wild-type RAR. In addition, NPM-RAR decreases basal transcription from some promoters and acts in a dominant-negative fashion when co-transfected with wild-type RAR. Both NPM-RAR and PML-RAR interact with the co-repressor protein SMRTe in a manner that is less sensitive than RAR to dissociation by retinoic acid. Retinoic acid induces binding of the co-activator protein RAC3. These data indicate that the NPM-RAR fusion proteins can modulate expression of retinoid-responsive genes in a positive or negative manner, depending on context of the promoter, and lend support to the hypothesis that aberrant transcriptional activation underlies the APL phenotype.
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Abstract
Nuclear hormone receptors are ligand-dependent transcription factors that regulate genes critical to such biological processes as development, reproduction, and homeostasis. Interestingly, these receptors can function as molecular switches, alternating between states of transcriptional repression and activation, depending on the absence or presence of cognate hormone, respectively. In the absence of hormone, several nuclear receptors actively repress transcription of target genes via interactions with the nuclear receptor corepressors SMRT and NCoR. Upon binding of hormone, these corepressors dissociate away from the DNA-bound receptor, which subsequently recruits a nuclear receptor coactivator (NCoA) complex. Prominent among these coactivators is the SRC (steroid receptor coactivator) family, which consists of SRC-1, TIF2/GRIP1, and RAC3/ACTR/pCIP/AIB-1. These cofactors interact with nuclear receptors in a ligand-dependent manner and enhance transcriptional activation by the receptor via histone acetylation/methylation and recruitment of additional cofactors such as CBP/p300. This review focuses on the mechanism of action of SRC coactivators in terms of interactions with receptors and activation of transcription. Specifically, the roles of the highly conserved LXXLL motifs in mediating SRC function will be detailed. Additionally, potential diversity among SRC family members, as well as several recently cloned SRC-associated cofactors, will be discussed.
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Affiliation(s)
- C Leo
- Department of Pharmacology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, USA
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Abstract
In higher eukaryotes, steroids/thyroid hormones and many lipophilic compounds regulate cellular physiology through binding to the steroid/nuclear receptor proteins. Steroid/nuclear receptors are ligand-dependent transcriptional activators that can stimulate gene expression. This transcriptional activation plays a pivotal role in hormone-regulated physiological and pharmacological responses. In recent years, several steroid/nuclear receptor cofactors have been identified and found to interact with the receptor and modulate its transcriptional activity. Among these cofactors, a family of three co-activators has been the focus of intense studies. Although gaps remain, progress has been made in understanding how a given co-activator interacts with the receptor and promotes transcriptional activation. We are beginning to understand co-activator action; for instance, several studies have established the molecular basis of antagonism by anti-hormones and the connection of co-activators with human cancers.
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Affiliation(s)
- J D Chen
- Department of Pharmacology and Molecular Toxicology, University of Massachusetts Medical School, Worcester 01655-0126, USA
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Leo C, Li H, Chen JD. Differential mechanisms of nuclear receptor regulation by receptor-associated coactivator 3. J Biol Chem 2000; 275:5976-82. [PMID: 10681591 DOI: 10.1074/jbc.275.8.5976] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Steroid and nuclear receptor coactivators (NCoAs) have been implicated in the regulation of nuclear receptor function by enhancing ligand-dependent transcriptional activation of target gene expression. We have previously isolated receptor-associated coactivator 3 (RAC3), which belongs to the steroid receptor coactivator family. In this study, we investigated the differential mechanisms by which RAC3 interacts with and modulates the transcriptional activity of different nuclear receptors. We found that the vitamin D receptor (VDR) and estrogen receptor beta interact with different alpha-helical LXXLL motifs of RAC3. Peptides corresponding to these motifs have diverse affinities for the VDR and estrogen receptor beta, and mutation of specific motifs differentially impairs the ability of RAC3 to interact with these receptors in vitro. Consequently, these mutations inhibit the enhancement of transcriptional activation by these receptors in vivo. Furthermore, we found that the activation function-2 (AF-2) domain of the retinoid X receptor interferes with RAC3 binding to a DNA-bound VDR/retinoid X receptor (RXR) heterodimer, whereas the VDR AF-2 domain is required for this interaction. These results suggest a receptor-specific binding preference for the different LXXLL motifs of RAC3, which may provide flexibility for RAC3 to differentially regulate the function of different nuclear receptors.
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Affiliation(s)
- C Leo
- Department of Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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Kraus WL, Manning ET, Kadonaga JT. Biochemical analysis of distinct activation functions in p300 that enhance transcription initiation with chromatin templates. Mol Cell Biol 1999; 19:8123-35. [PMID: 10567538 PMCID: PMC84897 DOI: 10.1128/mcb.19.12.8123] [Citation(s) in RCA: 193] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/1999] [Accepted: 09/09/1999] [Indexed: 12/21/2022] Open
Abstract
To investigate the mechanisms of transcriptional enhancement by the p300 coactivator, we analyzed wild-type and mutant versions of p300 with a chromatin transcription system in vitro. Estrogen receptor, NF-kappaB p65 plus Sp1, and Gal4-VP16 were used as different sequence-specific activators. The CH3 domain (or E1A-binding region) was found to be essential for the function of each of the activators tested. The bromodomain was also observed to be generally important for p300 coactivator activity, though to a lesser extent than the CH3 domain/E1A-binding region. The acetyltransferase activity and the C-terminal region (containing the steroid receptor coactivator/p160-binding region and the glutamine-rich region) were each found to be important for activation by estrogen receptor but not for that by Gal4-VP16. The N-terminal region of p300, which had been previously found to interact with nuclear hormone receptors, was not seen to be required for any of the activators, including estrogen receptor. Single-round transcription experiments revealed that the functionally important subregions of p300 contribute to its ability to promote the assembly of transcription initiation complexes. In addition, the acetyltransferase activity of p300 was observed to be distinct from the broadly essential activation function of the CH3 domain/E1A-binding region. These results indicate that specific regions of p300 possess distinct activation functions that are differentially required to enhance the assembly of transcription initiation complexes. Interestingly, with the estrogen receptor, four distinct regions of p300 each have an essential role in the transcription activation process. These data exemplify a situation in which a network of multiple activation functions is required to achieve gene transcription.
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Affiliation(s)
- W L Kraus
- Department of Biology and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093-0347, USA
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Thenot S, Charpin M, Bonnet S, Cavailles V. Estrogen receptor cofactors expression in breast and endometrial human cancer cells. Mol Cell Endocrinol 1999; 156:85-93. [PMID: 10612426 DOI: 10.1016/s0303-7207(99)00139-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In order to approach the molecular basis of the tissue-specific agonistic activity of antioestrogens, we have compared, at the mRNA level, the expression of various transcriptional cofactors (activators or repressors) of estrogen receptors in different breast (MCF7, ZR75-1, T47D, MDA-MB231) and endometrial (Ishikawa, RL-95-2 and HEC1A) human cancer cell lines. We showed that for SRC-1, CBP, TIF1alpha, RIP140, N-CoR, and SMRT, no significant differences in the expression levels were observed between breast and endometrial cells. For TIF1alpha mRNA, both isoforms were also detected at similar levels in all the cells tested. By contrast, over-expression of AIB1 mRNA was observed in MCF7 cells, but not in other breast or endometrial cells, irrespective of their ER-status. We then used protein-protein interaction assay (far-Western blot) to confirm the increased expression of at least one of the p160 proteins in MCF7 cells. Finally, we demonstrated that RIP140 mRNA is directly induced by estrogens in ER-positive MCF7 breast cancer cell lines but not in Ishikawa endometrial cells. Together these results indicate that some differences exist between breast and endometrial cancer cell lines at the level of estrogen receptor transcription cofactor expression.
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Affiliation(s)
- S Thenot
- University of Montpellier and Institut National de la Santé et de la Recherche Médicale, Hormones and Cancer (U148), France
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Tonetti DA, Jordan VC. The estrogen receptor: a logical target for the prevention of breast cancer with antiestrogens. J Mammary Gland Biol Neoplasia 1999; 4:401-13. [PMID: 10705923 DOI: 10.1023/a:1018722502034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A strategy for the prevention of breast cancer has been refined over the last century beginning with the first observation that oophorectomy caused disease regression in some patients, to the identification of the estrogen receptor some 60 years later, and finally to the synthesis of the first nonsteroidal antiestrogen. Tamoxifen was the first clinically useful antiestrogen and has been used for the treatment of breast cancer for the last twenty-one years in the United States. It is therefore a logical progression that antiestrogens are now recognized as useful agents for the prevention of breast cancer. We will discuss the estrogen receptor as a target for the treatment and now the prevention of breast cancer. Data from the National Surgical and Bowel Project (NSABP)4 tamoxifen prevention trial will be discussed with the preliminary results of two other European studies. The status of breast cancer prevention to date involves the comparison of the current standard of prevention, tamoxifen, with the osteoporosis prevention drug, raloxifene in an ongoing trial called Study of Tamoxifen and Raloxifene (STAR).
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Affiliation(s)
- D A Tonetti
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611, USA.
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