1
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Dent SYR. KAT tales: Functions of Gcn5 and PCAF lysine acetyltransferases in SAGA and ATAC. J Biol Chem 2024; 300:107744. [PMID: 39222683 PMCID: PMC11439848 DOI: 10.1016/j.jbc.2024.107744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 08/07/2024] [Accepted: 08/27/2024] [Indexed: 09/04/2024] Open
Abstract
The Allis group identified Gcn5 as the first transcription-related lysine acetyltransferase in 1996, providing a molecular "missing link" between chromatin organization and gene regulation. This review will focus on functions subsequently identified for Gcn5 and the closely related PCAF protein, in the context of two major complexes, SAGA and ATAC, and how the study of these enzymes informs long standing questions regarding the importance of lysine acetylation.
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Affiliation(s)
- Sharon Y R Dent
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer, Center for Cancer Epigenetics, University of Texas M.D. Anderson/UTHealth Houston Graduate School of Biomedical Sciences, Houston, Texas, USA.
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2
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Malone CF, Mabe NW, Forman AB, Alexe G, Engel KL, Chen YJC, Soeung M, Salhotra S, Basanthakumar A, Liu B, Dent SYR, Stegmaier K. The KAT module of the SAGA complex maintains the oncogenic gene expression program in MYCN-amplified neuroblastoma. SCIENCE ADVANCES 2024; 10:eadm9449. [PMID: 38820154 PMCID: PMC11141635 DOI: 10.1126/sciadv.adm9449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 04/29/2024] [Indexed: 06/02/2024]
Abstract
Pediatric cancers are frequently driven by genomic alterations that result in aberrant transcription factor activity. Here, we used functional genomic screens to identify multiple genes within the transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex as selective dependencies for MYCN-amplified neuroblastoma, a disease of dysregulated development driven by an aberrant oncogenic transcriptional program. We characterized the DNA recruitment sites of the SAGA complex in neuroblastoma and the consequences of loss of SAGA complex lysine acetyltransferase (KAT) activity on histone acetylation and gene expression. We demonstrate that loss of SAGA complex KAT activity is associated with reduced MYCN binding on chromatin, suppression of MYC/MYCN gene expression programs, and impaired cell cycle progression. Further, we showed that the SAGA complex is pharmacologically targetable in vitro and in vivo with a KAT2A/KAT2B proteolysis targeting chimeric. Our findings expand our understanding of the histone-modifying complexes that maintain the oncogenic transcriptional state in this disease and suggest therapeutic potential for inhibitors of SAGA KAT activity in MYCN-amplified neuroblastoma.
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Affiliation(s)
- Clare F. Malone
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Nathaniel W. Mabe
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Alexandra B. Forman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Gabriela Alexe
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Kathleen L. Engel
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ying-Jiun C. Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- The Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Melinda Soeung
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Silvi Salhotra
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Allen Basanthakumar
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Bin Liu
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- The Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sharon Y. R. Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- The Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kimberly Stegmaier
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, USA
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3
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Li J, Cao Y, Yang Y, Ma H, Zhao J, Zhang Y, Liu N. Quantitative Acetylomics Reveals Substrates of Lysine Acetyltransferase GCN5 in Adult and Aging Drosophila. J Proteome Res 2023; 22:2909-2924. [PMID: 37545086 DOI: 10.1021/acs.jproteome.3c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Protein lysine acetylation is a dynamic post-translational modification (PTM) that regulates a wide spectrum of cellular events including aging. General control nonderepressible 5 (GCN5) is a highly conserved lysine acetyltransferase (KAT). However, the acetylation substrates of GCN5 in vivo remain poorly studied, and moreover, how lysine acetylation changes with age and the contribution of KATs to aging remain to be addressed. Here, using Drosophila, we perform label-free quantitative acetylomic analysis, identifying new substrates of GCN5 in the adult and aging process. We further characterize the dynamics of protein acetylation with age, which exhibits a trend of increase. Since the expression of endogenous fly Gcn5 progressively increases during aging, we reason that, by combining the substrate analysis, the increase in acetylation with age is triggered, at least in part, by GCN5. Collectively, our study substantially expands the atlas of GCN5 substrates in vivo, provides a resource of protein acetylation that naturally occurs with age, and demonstrates how individual KAT contributes to the aging acetylome.
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Affiliation(s)
- Jingshu Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ye Cao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yun Yang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huanhuan Ma
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Zhao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaoyang Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- Shanghai Key Laboratory of Aging Studies, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
| | - Nan Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
- Shanghai Key Laboratory of Aging Studies, 100 Hai Ke Rd., Pudong, Shanghai 201210, China
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4
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Chen Y, Zeng W, Yu S, Gao S, Zhou J. Chromatin regulator Ahc1p co-regulates nitrogen metabolism via interactions with multiple transcription factors in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2023; 662:31-38. [PMID: 37099808 DOI: 10.1016/j.bbrc.2023.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 04/04/2023] [Indexed: 04/28/2023]
Abstract
Chromatin regulation is an important gene expression/regulation system, but little is known about how it affects nitrogen metabolism in Saccharomyces cerevisiae. A previous study demonstrated the regulatory role of the chromatin regulator Ahc1p on multiple key genes of nitrogen metabolism in S. cerevisiae, but the regulatory mechanism remains unknown. In this study, multiple key nitrogen metabolism genes directly regulated by Ahc1p were identified, and the transcription factors interacting with Ahc1p were analyzed. It was ultimately found that Ahc1p may regulate some key nitrogen metabolism genes in two ways. First, Ahc1p acts as a co-factor and is recruited with transcription factors such as Rtg3p or Gcr1p to facilitate transcription complex binding to target gene core promoters and promote transcription initiation. Second, Ahc1p binds at enhancers to promote the transcription of target genes in concert with transcription factors. This study furthers the understanding of the regulatory network of nitrogen metabolism in S. cerevisiae from an epigenetic perspective.
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Affiliation(s)
- Yu Chen
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China; Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China
| | - Weizhu Zeng
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China
| | - Shiqin Yu
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China
| | - Song Gao
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
| | - Jingwen Zhou
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China; Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China.
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5
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George S, Blum HR, Torres‐Zelada EF, Estep GN, Hegazy YA, Speer GM, Weake VM. The interaction between the Dbf4 ortholog Chiffon and Gcn5 is conserved in Dipteran insect species. INSECT MOLECULAR BIOLOGY 2022; 31:734-746. [PMID: 35789507 PMCID: PMC9796610 DOI: 10.1111/imb.12800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Chiffon is the sole Drosophila ortholog of Dbf4, the regulatory subunit for the cell-cycle kinase Cdc7 that initiates DNA replication. In Drosophila, the chiffon gene encodes two polypeptides with independent activities. Chiffon-A contains the conserved Dbf4 motifs and interacts with Cdc7 to form the Dbf4-dependent Kinase (DDK) complex, which is essential for a specialized form of DNA replication. In contrast, Chiffon-B binds the histone acetyltransferase Gcn5 to form the Chiffon histone acetyltransferase (CHAT) complex, which is necessary for histone H3 acetylation and viability. Previous studies have shown that the Chiffon-B region is only present within insects. However, it was unclear how widely the interaction between Chiffon-B and Gcn5 was conserved among insect species. To examine this, we performed yeast two-hybrid assays using Chiffon-B and Gcn5 from a variety of insect species and found that Chiffon-B and Gcn5 interact in Diptera species such as Australian sheep blowfly and yellow fever mosquito. Protein domain analysis identified that Chiffon-B has features of acidic transcriptional activators such as Gal4 or VP16. We propose that the CHAT complex plays a critical role in a biological process that is unique to Dipterans and could therefore be a potential target for pest control strategies.
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Affiliation(s)
- Smitha George
- Department of BiochemistryPurdue UniversityWest LafayetteIndianaUSA
- Present address:
Van Andel InstituteGrand RapidsMichiganUSA
| | - Hannah R. Blum
- Department of BiochemistryPurdue UniversityWest LafayetteIndianaUSA
| | | | - Grace N. Estep
- Department of BiochemistryPurdue UniversityWest LafayetteIndianaUSA
| | | | - Gina M. Speer
- Department of BiochemistryPurdue UniversityWest LafayetteIndianaUSA
| | - Vikki M. Weake
- Department of BiochemistryPurdue UniversityWest LafayetteIndianaUSA
- Purdue University Center for Cancer ResearchPurdue UniversityWest LafayetteIndianaUSA
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6
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Mittal C, Lang O, Lai WKM, Pugh BF. An integrated SAGA and TFIID PIC assembly pathway selective for poised and induced promoters. Genes Dev 2022; 36:985-1001. [PMID: 36302553 PMCID: PMC9732905 DOI: 10.1101/gad.350026.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/11/2022] [Indexed: 02/05/2023]
Abstract
Genome-wide, little is understood about how proteins organize at inducible promoters before and after induction and to what extent inducible and constitutive architectures depend on cofactors. We report that sequence-specific transcription factors and their tethered cofactors (e.g., SAGA [Spt-Ada-Gcn5-acetyltransferase], Mediator, TUP, NuA4, SWI/SNF, and RPD3-L) are generally bound to promoters prior to induction ("poised"), rather than recruited upon induction, whereas induction recruits the preinitiation complex (PIC) to DNA. Through depletion and/or deletion experiments, we show that SAGA does not function at constitutive promoters, although a SAGA-independent Gcn5 acetylates +1 nucleosomes there. When inducible promoters are poised, SAGA catalyzes +1 nucleosome acetylation but not PIC assembly. When induced, SAGA catalyzes acetylation, deubiquitylation, and PIC assembly. Surprisingly, SAGA mediates induction by creating a PIC that allows TFIID (transcription factor II-D) to stably associate, rather than creating a completely TFIID-independent PIC, as generally thought. These findings suggest that inducible systems, where present, are integrated with constitutive systems.
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Affiliation(s)
- Chitvan Mittal
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Olivia Lang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - William K M Lai
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - B Franklin Pugh
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
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7
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Torres-Zelada EF, George S, Blum HR, Weake VM. Chiffon triggers global histone H3 acetylation and expression of developmental genes in Drosophila embryos. J Cell Sci 2021; 135:274078. [PMID: 34908116 PMCID: PMC8917357 DOI: 10.1242/jcs.259132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 12/06/2021] [Indexed: 11/20/2022] Open
Abstract
The histone acetyltransferase Gcn5 is critical for gene expression and development. In Drosophila, Gcn5 is part of four complexes (SAGA, ATAC, CHAT and ADA) that are essential for fly viability and have key roles in regulating gene expression. Here, we show that although the SAGA, ADA and CHAT complexes play redundant roles in embryonic gene expression, the insect-specific CHAT complex uniquely regulates expression of a subset of developmental genes. We also identify a substantial decrease in histone acetylation in chiffon mutant embryos that exceeds that observed in Ada2b, suggesting broader roles for Chiffon in regulating histone acetylation outside of the Gcn5 complexes. The chiffon gene encodes two independent polypeptides that nucleate formation of either the CHAT or Dbf4-dependent kinase (DDK) complexes. DDK includes the cell cycle kinase Cdc7, which is necessary for maternally driven DNA replication in the embryo. We identify a temporal switch between the expression of these chiffon gene products during a short window during the early nuclear cycles in embryos that correlates with the onset of zygotic genome activation, suggesting a potential role for CHAT in this process. This article has an associated First Person interview with the first author of the paper. Summary: Chiffon within the Gcn5-containing CHAT complex plays key roles in embryonic gene expression and histone H3 acetylation in Drosophila.
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Affiliation(s)
| | - Smitha George
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Hannah R Blum
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.,Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, USA
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8
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Herbst DA, Esbin MN, Louder RK, Dugast-Darzacq C, Dailey GM, Fang Q, Darzacq X, Tjian R, Nogales E. Structure of the human SAGA coactivator complex. Nat Struct Mol Biol 2021; 28:989-996. [PMID: 34811519 PMCID: PMC8660637 DOI: 10.1038/s41594-021-00682-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/05/2021] [Indexed: 12/16/2022]
Abstract
The SAGA complex is a regulatory hub involved in gene regulation, chromatin modification, DNA damage repair and signaling. While structures of yeast SAGA (ySAGA) have been reported, there are noteworthy functional and compositional differences for this complex in metazoans. Here we present the cryogenic-electron microscopy (cryo-EM) structure of human SAGA (hSAGA) and show how the arrangement of distinct structural elements results in a globally divergent organization from that of yeast, with a different interface tethering the core module to the TRRAP subunit, resulting in a dramatically altered geometry of functional elements and with the integration of a metazoan-specific splicing module. Our hSAGA structure reveals the presence of an inositol hexakisphosphate (InsP6) binding site in TRRAP and an unusual property of its pseudo-(Ψ)PIKK. Finally, we map human disease mutations, thus providing the needed framework for structure-guided drug design of this important therapeutic target for human developmental diseases and cancer.
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Affiliation(s)
- Dominik A Herbst
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Meagan N Esbin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
| | - Robert K Louder
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
- Biophysics Graduate Group, University of California, Berkeley, CA, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Claire Dugast-Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Gina M Dailey
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Qianglin Fang
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- School of Public Health, Sun Yat-sen University, Shenzhen, China
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Eva Nogales
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
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9
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Soffers JHM, Alcantara SGM, Li X, Shao W, Seidel CW, Li H, Zeitlinger J, Abmayr SM, Workman JL. The SAGA core module is critical during Drosophila oogenesis and is broadly recruited to promoters. PLoS Genet 2021; 17:e1009668. [PMID: 34807910 PMCID: PMC8648115 DOI: 10.1371/journal.pgen.1009668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 12/06/2021] [Accepted: 10/22/2021] [Indexed: 11/19/2022] Open
Abstract
The Spt/Ada-Gcn5 Acetyltransferase (SAGA) coactivator complex has multiple modules with different enzymatic and non-enzymatic functions. How each module contributes to gene expression is not well understood. During Drosophila oogenesis, the enzymatic functions are not equally required, which may indicate that different genes require different enzymatic functions. An analogy for this phenomenon is the handyman principle: while a handyman has many tools, which tool he uses depends on what requires maintenance. Here we analyzed the role of the non-enzymatic core module during Drosophila oogenesis, which interacts with TBP. We show that depletion of SAGA-specific core subunits blocked egg chamber development at earlier stages than depletion of enzymatic subunits. These results, as well as additional genetic analyses, point to an interaction with TBP and suggest a differential role of SAGA modules at different promoter types. However, SAGA subunits co-occupied all promoter types of active genes in ChIP-seq and ChIP-nexus experiments, and the complex was not specifically associated with distinct promoter types in the ovary. The high-resolution genomic binding profiles were congruent with SAGA recruitment by activators upstream of the start site, and retention on chromatin by interactions with modified histones downstream of the start site. Our data illustrate that a distinct genetic requirement for specific components may conceal the fact that the entire complex is physically present and suggests that the biological context defines which module functions are critical. Embryonic development critically relies on the differential expression of genes in different tissues. This involves the dynamic interplay between DNA, sequence-specific transcription factors, coactivators and chromatin remodelers, which guide the transcription machinery to the appropriate promoters for productive transcription. To understand how this happens at the molecular level, we need to understand when and how coactivator complexes such as SAGA function. SAGA consists of multiple modules with well characterized enzymatic functions. This study shows that the non-enzymatic core module of SAGA is required for Drosophila oogenesis, while the enzymatic functions are largely dispensable. Despite this differential requirement, SAGA subunits appear to be broadly recruited to all promoter types, consistent with the biochemical integrity of the complex. These results suggest that genetic requirements for different modules depend on the developmental demands.
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Affiliation(s)
- Jelly H. M. Soffers
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Sergio G-M Alcantara
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Xuanying Li
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Wanqing Shao
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Christopher W. Seidel
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Hua Li
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Pathology and Laboratory Medicine, University of Kansas School of Medicine, Kansas City, Kansas, United States of America
| | - Susan M. Abmayr
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, United States of America
| | - Jerry L. Workman
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- * E-mail:
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10
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The GCN5: its biological functions and therapeutic potentials. Clin Sci (Lond) 2021; 135:231-257. [PMID: 33443284 DOI: 10.1042/cs20200986] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
General control non-depressible 5 (GCN5) or lysine acetyltransferase 2A (KAT2A) is one of the most highly studied histone acetyltransferases. It acts as both histone acetyltransferase (HAT) and lysine acetyltransferase (KAT). As an HAT it plays a pivotal role in the epigenetic landscape and chromatin modification. Besides, GCN5 regulates a wide range of biological events such as gene regulation, cellular proliferation, metabolism and inflammation. Imbalance in the GCN5 activity has been reported in many disorders such as cancer, metabolic disorders, autoimmune disorders and neurological disorders. Therefore, unravelling the role of GCN5 in different diseases progression is a prerequisite for both understanding and developing novel therapeutic agents of these diseases. In this review, we have discussed the structural features, the biological function of GCN5 and the mechanical link with the diseases associated with its imbalance. Moreover, the present GCN5 modulators and their limitations will be presented in a medicinal chemistry perspective.
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11
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Stanek TJ, Gennaro VJ, Tracewell MA, Di Marcantonio D, Pauley KL, Butt S, McNair C, Wang F, Kossenkov AV, Knudsen KE, Butt T, Sykes SM, McMahon SB. The SAGA complex regulates early steps in transcription via its deubiquitylase module subunit USP22. EMBO J 2021; 40:e102509. [PMID: 34155658 PMCID: PMC8365265 DOI: 10.15252/embj.2019102509] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 04/10/2021] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
The SAGA coactivator complex is essential for eukaryotic transcription and comprises four distinct modules, one of which contains the ubiquitin hydrolase USP22. In yeast, the USP22 ortholog deubiquitylates H2B, resulting in Pol II Ser2 phosphorylation and subsequent transcriptional elongation. In contrast to this H2B-associated role in transcription, we report here that human USP22 contributes to the early stages of stimulus-responsive transcription, where USP22 is required for pre-initiation complex (PIC) stability. Specifically, USP22 maintains long-range enhancer-promoter contacts and controls loading of Mediator tail and general transcription factors (GTFs) onto promoters, with Mediator core recruitment being USP22-independent. In addition, we identify Mediator tail subunits MED16 and MED24 and the Pol II subunit RBP1 as potential non-histone substrates of USP22. Overall, these findings define a role for human SAGA within the earliest steps of transcription.
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Affiliation(s)
- Timothy J Stanek
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Victoria J Gennaro
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Mason A Tracewell
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | | | - Kristen L Pauley
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Sabrina Butt
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Christopher McNair
- Department of Cancer BiologySidney Kimmel Medical College and Sidney Kimmel Cancer CenterThomas Jefferson UniversityPhiladelphiaPAUSA
| | | | | | - Karen E Knudsen
- Department of Cancer BiologySidney Kimmel Medical College and Sidney Kimmel Cancer CenterThomas Jefferson UniversityPhiladelphiaPAUSA
| | | | - Stephen M Sykes
- Blood Cell Development and Function ProgramFox Chase Cancer CenterPhiladelphiaPAUSA
| | - Steven B McMahon
- Department of Biochemistry and Molecular BiologySidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
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12
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Chen YJC, Dent SYR. Conservation and diversity of the eukaryotic SAGA coactivator complex across kingdoms. Epigenetics Chromatin 2021; 14:26. [PMID: 34112237 PMCID: PMC8194025 DOI: 10.1186/s13072-021-00402-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/03/2021] [Indexed: 12/27/2022] Open
Abstract
The SAGA complex is an evolutionarily conserved transcriptional coactivator that regulates gene expression through its histone acetyltransferase and deubiquitylase activities, recognition of specific histone modifications, and interactions with transcription factors. Multiple lines of evidence indicate the existence of distinct variants of SAGA among organisms as well as within a species, permitting diverse functions to dynamically regulate cellular pathways. Our co-expression analysis of genes encoding human SAGA components showed enrichment in reproductive organs, brain tissues and the skeletal muscle, which corresponds to their established roles in developmental programs, emerging roles in neurodegenerative diseases, and understudied functions in specific cell types. SAGA subunits modulate growth, development and response to various stresses from yeast to plants and metazoans. In metazoans, SAGA further participates in the regulation of differentiation and maturation of both innate and adaptive immune cells, and is associated with initiation and progression of diseases including a broad range of cancers. The evolutionary conservation of SAGA highlights its indispensable role in eukaryotic life, thus deciphering the mechanisms of action of SAGA is key to understanding fundamental biological processes throughout evolution. To illuminate the diversity and conservation of this essential complex, here we discuss variations in composition, essentiality and co-expression of component genes, and its prominent functions across Fungi, Plantae and Animalia kingdoms.
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Affiliation(s)
- Ying-Jiun C Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
- The Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sharon Y R Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA.
- The Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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13
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Soffers JHM, Workman JL. The SAGA chromatin-modifying complex: the sum of its parts is greater than the whole. Genes Dev 2021; 34:1287-1303. [PMID: 33004486 PMCID: PMC7528701 DOI: 10.1101/gad.341156.120] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this review, Soffers and Workman discuss the initial discovery of the canonical SAGA complex, the subsequent studies that have shaped our view on the internal organization of its subunits into modules, and the latest structural work that visualizes the modules and provides insights into their function. There are many large protein complexes involved in transcription in a chromatin context. However, recent studies on the SAGA coactivator complex are generating new paradigms for how the components of these complexes function, both independently and in concert. This review highlights the initial discovery of the canonical SAGA complex 23 years ago, our evolving understanding of its modular structure and the relevance of its modular nature for its coactivator function in gene regulation.
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Affiliation(s)
- Jelly H M Soffers
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Jerry L Workman
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
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14
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Nuño-Cabanes C, García-Molinero V, Martín-Expósito M, Gas ME, Oliete-Calvo P, García-Oliver E, de la Iglesia-Vayá M, Rodríguez-Navarro S. SAGA-CORE subunit Spt7 is required for correct Ubp8 localization, chromatin association and deubiquitinase activity. Epigenetics Chromatin 2020; 13:46. [PMID: 33115507 PMCID: PMC7594455 DOI: 10.1186/s13072-020-00367-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 10/15/2020] [Indexed: 02/07/2023] Open
Abstract
Background Histone H2B deubiquitination is performed by numerous deubiquitinases in eukaryotic cells including Ubp8, the catalytic subunit of the tetrameric deubiquitination module (DUBm: Ubp8; Sus1; Sgf11; Sgf73) of the Spt-Ada-Gcn5 acetyltransferase (SAGA). Ubp8 is linked to the rest of SAGA through Sgf73 and is activated by the adaptors Sus1 and Sgf11. It is unknown if DUBm/Ubp8 might also work in a SAGA-independent manner. Results Here we report that a tetrameric DUBm is assembled independently of the SAGA–CORE components SPT7, ADA1 and SPT20. In the absence of SPT7, i.e., independent of the SAGA complex, Ubp8 and Sus1 are poorly recruited to SAGA-dependent genes and to chromatin. Notably, cells lacking Spt7 or Ada1, but not Spt20, show lower levels of nuclear Ubp8 than wild-type cells, suggesting a possible role for SAGA–CORE subunits in Ubp8 localization. Last, deletion of SPT7 leads to defects in Ubp8 deubiquitinase activity in in vivo and in vitro assays. Conclusions Collectively, our studies show that the DUBm tetrameric structure can form without a complete intact SAGA–CORE complex and that it includes full-length Sgf73. However, subunits of this SAGA–CORE influence DUBm association with chromatin, its localization and its activity.
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Affiliation(s)
- Carme Nuño-Cabanes
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (CSIC), C/Jaume Roig 11, 46010, Valencia, Spain.,Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - Varinia García-Molinero
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - Manuel Martín-Expósito
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (CSIC), C/Jaume Roig 11, 46010, Valencia, Spain.,Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - María-Eugenia Gas
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - Paula Oliete-Calvo
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - Encar García-Oliver
- Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - María de la Iglesia-Vayá
- Brain Connectivity Lab. Joint Unit FISABIO & Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas (CSIC), C/Jaume Roig 11, 46010, Valencia, Spain. .,Gene Expression and RNA Metabolism Laboratory, Centro de Investigación Príncipe Felipe (CIPF), C/E. Primo Yúfera 3, 46012, Valencia, Spain.
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15
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Espinola-Lopez JM, Tan S. The Ada2/Ada3/Gcn5/Sgf29 histone acetyltransferase module. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194629. [PMID: 32890768 DOI: 10.1016/j.bbagrm.2020.194629] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 01/14/2023]
Abstract
Histone post-translational modifications are essential for the regulation of gene expression in eukaryotes. Gcn5 (KAT2A) is a histone acetyltransferase that catalyzes the post-translational modification at multiple positions of histone H3 through the transfer of acetyl groups to the free amino group of lysine residues. Gcn5 catalyzes histone acetylation in the context of a HAT module containing the Ada2, Ada3 and Sgf29 subunits of the parent megadalton SAGA transcriptional coactivator complex. Biochemical and structural studies have elucidated mechanisms for Gcn5's acetyl- and other acyltransferase activities on histone substrates, for histone H3 phosphorylation and histone H3 methylation crosstalks with histone H3 acetylation, and for how Ada2 increases Gcn5's histone acetyltransferase activity. Other studies have identified Ada2 isoforms in SAGA-related complexes and characterized variant Gcn5 HAT modules containing these Ada2 isoforms. In this review, we highlight biochemical and structural studies of Gcn5 and its functional interactions with Ada2, Ada3 and Sgf29.
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Affiliation(s)
- Jose M Espinola-Lopez
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Song Tan
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
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16
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What do the structures of GCN5-containing complexes teach us about their function? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194614. [PMID: 32739556 DOI: 10.1016/j.bbagrm.2020.194614] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022]
Abstract
Transcription initiation is a major regulatory step in eukaryotic gene expression. It involves the assembly of general transcription factors and RNA polymerase II into a functional pre-initiation complex at core promoters. The degree of chromatin compaction controls the accessibility of the transcription machinery to template DNA. Co-activators have critical roles in this process by actively regulating chromatin accessibility. Many transcriptional coactivators are multisubunit complexes, organized into distinct structural and functional modules and carrying multiple regulatory activities. The first nuclear histone acetyltransferase (HAT) characterized was General Control Non-derepressible 5 (Gcn5). Gcn5 was subsequently identified as a subunit of the HAT module of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, which is an experimental paradigm for multifunctional co-activators. We know today that Gcn5 is the catalytic subunit of multiple distinct co-activator complexes with specific functions. In this review, we summarize recent advances in the structure of Gcn5-containing co-activator complexes, most notably SAGA, and discuss how these new structural insights contribute to better understand their functions.
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17
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Torres-Zelada EF, Weake VM. The Gcn5 complexes in Drosophila as a model for metazoa. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194610. [PMID: 32735945 DOI: 10.1016/j.bbagrm.2020.194610] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 01/14/2023]
Abstract
The histone acetyltransferase Gcn5 is conserved throughout eukaryotes where it functions as part of large multi-subunit transcriptional coactivator complexes that stimulate gene expression. Here, we describe how studies in the model insect Drosophila melanogaster have provided insight into the essential roles played by Gcn5 in the development of multicellular organisms. We outline the composition and activity of the four different Gcn5 complexes in Drosophila: the Spt-Ada-Gcn5 Acetyltransferase (SAGA), Ada2a-containing (ATAC), Ada2/Gcn5/Ada3 transcription activator (ADA), and Chiffon Histone Acetyltransferase (CHAT) complexes. Whereas the SAGA and ADA complexes are also present in the yeast Saccharomyces cerevisiae, ATAC has only been identified in other metazoa such as humans, and the CHAT complex appears to be unique to insects. Each of these Gcn5 complexes is nucleated by unique Ada2 homologs or splice isoforms that share conserved N-terminal domains, and differ only in their C-terminal domains. We describe the common and specialized developmental functions of each Gcn5 complex based on phenotypic analysis of mutant flies. In addition, we outline how gene expression studies in mutant flies have shed light on the different biological roles of each complex. Together, these studies highlight the key role that Drosophila has played in understanding the expanded biological function of Gcn5 in multicellular eukaryotes.
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Affiliation(s)
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA; Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA.
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18
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Koutelou E, Farria AT, Dent SYR. Complex functions of Gcn5 and Pcaf in development and disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194609. [PMID: 32730897 DOI: 10.1016/j.bbagrm.2020.194609] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022]
Abstract
A wealth of biochemical and cellular data, accumulated over several years by multiple groups, has provided a great degree of insight into the molecular mechanisms of actions of GCN5 and PCAF in gene activation. Studies of these lysine acetyltransferases (KATs) in vitro, in cultured cells, have revealed general mechanisms for their recruitment by sequence-specific binding factors and their molecular functions as transcriptional co-activators. Genetic studies indicate that GCN5 and PCAF are involved in multiple developmental processes in vertebrates, yet our understanding of their molecular functions in these contexts remains somewhat rudimentary. Understanding the functions of GCN5/PCAF in developmental processes provides clues to the roles of these KATs in disease states. Here we will review what is currently known about the developmental roles of GCN5 and PCAF, as well as emerging role of these KATs in oncogenesis.
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Affiliation(s)
- Evangelia Koutelou
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Aimee T Farria
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Sharon Y R Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America.
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19
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Nuño-Cabanes C, Rodríguez-Navarro S. The promiscuity of the SAGA complex subunits: Multifunctional or moonlighting proteins? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194607. [PMID: 32712338 DOI: 10.1016/j.bbagrm.2020.194607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022]
Abstract
Gene expression, the decoding of DNA information into accessible instructions for protein synthesis, is a complex process in which multiple steps, including transcription, mRNA processing and mRNA export, are regulated by different factors. One of the first steps in this process involves chemical and structural changes in chromatin to allow transcription. For such changes to occur, histone tail and DNA epigenetic modifications foster the binding of transcription factors to promoter regions. The SAGA coactivator complex plays a crucial role in this process by mediating histone acetylation through Gcn5, and histone deubiquitination through Ubp8 enzymes. However, most SAGA subunits interact physically with other proteins beyond the SAGA complex. These interactions could represent SAGA-independent functions or a mechanism to widen SAGA multifunctionality. Among the different mechanisms to perform more than one function, protein moonlighting defines unrelated molecular activities for the same polypeptide sequence. Unlike pleiotropy, where a single gene can affect different phenotypes, moonlighting necessarily involves separate functions of a protein at the molecular level. In this review we describe in detail some of the alternative physical interactions of several SAGA subunits. In some cases, the alternative role constitutes a clear moonlighting function, whereas in most of them the lack of molecular evidence means that we can only define these interactions as promiscuous that require further work to verify if these are moonlighting functions.
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Affiliation(s)
- Carme Nuño-Cabanes
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia (CSIC), Jaume Roig, 11, E-46010 Valencia, Spain
| | - Susana Rodríguez-Navarro
- Gene Expression and RNA Metabolism Laboratory, Instituto de Biomedicina de Valencia (CSIC), Jaume Roig, 11, E-46010 Valencia, Spain.
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20
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Non-histone protein acetylation by the evolutionarily conserved GCN5 and PCAF acetyltransferases. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194608. [PMID: 32711095 DOI: 10.1016/j.bbagrm.2020.194608] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 01/08/2023]
Abstract
GCN5, conserved from yeast to humans, and the vertebrate specific PCAF, are lysine acetyltransferase enzymes found in large protein complexes. Both enzymes have well documented roles in the histone acetylation and the concomitant regulation of transcription. However, these enzymes also acetylate non-histone substrates to impact diverse aspects of cell physiology. Here, I review our current understanding of non-histone acetylation by GCN5 and PCAF across eukaryotes, from target identification to molecular mechanism and regulation. I focus mainly on budding yeast, where Gcn5 was first discovered, and mammalian systems, where the bulk of non-histone substrates have been characterized. I end the review by defining critical caveats and open questions that apply to all models.
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21
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Timmers HTM. SAGA and TFIID: Friends of TBP drifting apart. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194604. [PMID: 32673655 DOI: 10.1016/j.bbagrm.2020.194604] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 01/24/2023]
Abstract
Transcription initiation constitutes a major checkpoint in gene regulation across all living organisms. Control of chromatin function is tightly linked to this checkpoint, which is best illustrated by the SAGA coactivator. This evolutionary conserved complex of 18-20 subunits was first discovered as a Gcn5p-containing histone acetyltransferase, but it also integrates a histone H2B deubiquitinase. The SAGA subunits are organized in a modular fashion around its central core. Strikingly, this central module of SAGA shares a number of proteins with the central core of the basal transcription factor TFIID. In this review I will compare the SAGA and TFIID complexes with respect to their shared subunits, structural organization, enzymatic activities and chromatin binding. I will place a special emphasis on the ancestry of SAGA and TFIID subunits, which suggests that these complexes evolved to control the activity of TBP (TATA-binding protein) in directing the assembly of transcription initiation complexes.
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Affiliation(s)
- H Th Marc Timmers
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; German Cancer Consortium (DKTK) partner site Freiburg, 79106 Freiburg, Germany; Department of Urology, Medical Center-University of Freiburg, Breisacher Straße 66, 79106 Freiburg, Germany.
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22
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Cheon Y, Kim H, Park K, Kim M, Lee D. Dynamic modules of the coactivator SAGA in eukaryotic transcription. Exp Mol Med 2020; 52:991-1003. [PMID: 32616828 PMCID: PMC8080568 DOI: 10.1038/s12276-020-0463-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 02/08/2023] Open
Abstract
SAGA (Spt-Ada-Gcn5 acetyltransferase) is a highly conserved transcriptional coactivator that consists of four functionally independent modules. Its two distinct enzymatic activities, histone acetylation and deubiquitylation, establish specific epigenetic patterns on chromatin and thereby regulate gene expression. Whereas earlier studies emphasized the importance of SAGA in regulating global transcription, more recent reports have indicated that SAGA is involved in other aspects of gene expression and thus plays a more comprehensive role in regulating the overall process. Here, we discuss recent structural and functional studies of each SAGA module and compare the subunit compositions of SAGA with related complexes in yeast and metazoans. We discuss the regulatory role of the SAGA deubiquitylating module (DUBm) in mRNA surveillance and export, and in transcription initiation and elongation. The findings suggest that SAGA plays numerous roles in multiple stages of transcription. Further, we describe how SAGA is related to human disease. Overall, in this report, we illustrate the newly revealed understanding of SAGA in transcription regulation and disease implications for fine-tuning gene expression. A protein that helps add epigenetic information to genome, SAGA, controls many aspects of gene activation, potentially making it a target for cancer therapies. To fit inside the tiny cell nucleus, the genome is tightly packaged, and genes must be unpacked before they can be activated. Known to be important in genome opening, SAGA has now been shown to also play many roles in gene activation. Daeyoup Lee at the KAIST, Daejeon, South Korea, and co-workers have reviewed recent discoveries about SAGA’s structure, function, and roles in disease. They report that SAGA’s complex (19 subunits organized into four modules) allows it to play so many roles, genome opening, initiating transcription, and efficiently exporting mRNAs. Its master role means that malfunction of SAGA may be linked to many diseases.
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Affiliation(s)
- Youngseo Cheon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Harim Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Kyubin Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Minhoo Kim
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
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23
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Soffers JHM, Popova VV, Workman JLW. SAGA Structures Provide Mechanistic Models for Gene Activation. Trends Biochem Sci 2020; 45:547-549. [PMID: 32531226 DOI: 10.1016/j.tibs.2020.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/25/2020] [Accepted: 03/02/2020] [Indexed: 11/28/2022]
Abstract
Two recent reports by Cramer and Ben-Shem and colleagues present high-resolution structures of the yeast SAGA transcription coactivator complex. These are the first to resolve the stoichiometry and structure of the core. The core contains an octamer-like fold, flexibly links the enzymatic modules, and facilitates TBP loading onto TATA promoters.
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Affiliation(s)
| | - Varvara V Popova
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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24
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Mustachio LM, Roszik J, Farria A, Dent SYR. Targeting the SAGA and ATAC Transcriptional Coactivator Complexes in MYC-Driven Cancers. Cancer Res 2020; 80:1905-1911. [PMID: 32094302 DOI: 10.1158/0008-5472.can-19-3652] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/28/2020] [Accepted: 02/19/2020] [Indexed: 12/26/2022]
Abstract
Targeting epigenetic regulators, such as histone-modifying enzymes, provides novel strategies for cancer therapy. The GCN5 lysine acetyltransferase (KAT) functions together with MYC both during normal development and in oncogenesis. As transcription factors, MYC family members are difficult to target with small-molecule inhibitors, but the acetyltransferase domain and the bromodomain in GCN5 might provide alternative targets for disruption of MYC-driven functions. GCN5 is part of two distinct multiprotein histone-modifying complexes, SAGA and ATAC. This review summarizes key findings on the roles of SAGA and ATAC in embryo development and in cancer to better understand the functional relationships of these complexes with MYC family members, as well as their future potential as therapeutic targets.
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Affiliation(s)
- Lisa Maria Mustachio
- Departments of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jason Roszik
- Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Aimee Farria
- Departments of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Sharon Y R Dent
- Departments of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas. .,Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas.,Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas
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25
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Mustachio LM, Roszik J, Farria AT, Guerra K, Dent SYR. Repression of GCN5 expression or activity attenuates c-MYC expression in non-small cell lung cancer. Am J Cancer Res 2019; 9:1830-1845. [PMID: 31497362 PMCID: PMC6726999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023] Open
Abstract
Lung cancer causes the highest mortality in cancer-related deaths. As these cancers often become resistant to existing therapies, definition of novel molecular targets is needed. Epigenetic modifiers may provide such targets. Recent reports suggest that the histone acetyltransferase (HAT) module within the transcriptional coactivator SAGA complex plays a role in cancer, creating a new link between epigenetic regulators and this disease. GCN5 serves as a coactivator for MYC target genes, and here we investigate links between GCN5 and c-MYC in non-small cell lung cancer (NSCLC). Our data indicate that both GCN5 and c-MYC proteins are upregulated in mouse and human NSCLC cells compared to normal lung epithelial cells. This trend is observable only at the protein level, indicating that this upregulation occurs post-transcriptionally. Human NSCLC tissue data provided by The Cancer Genome Atlas (TCGA) indicates that GCN5 and c-MYC expression are positively associated with one another and with the expression of c-MYC target genes. Depletion of GCN5 in NSCLC cells reduces c-MYC expression, cell proliferation, and increases the population of necrotic cells. Similarly, inhibition of the GCN5 catalytic site using a commercially available probe reduces c-MYC expression, cell proliferation, and increases the percentage of cells undergoing apoptosis. Our findings suggest that GCN5 might provide a novel target for inhibition of NSCLC growth and progression.
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Affiliation(s)
- Lisa Maria Mustachio
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
| | - Jason Roszik
- Department of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
| | - Aimee T Farria
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
| | - Karla Guerra
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
| | - Sharon YR Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
- Department of Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer CenterHouston, Texas 77030, USA
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