Histone acetyltransferase activity and interaction with ADA2 are critical for GCN5 function invivo

Candau, Reyes; Zhou, Jianxin; Allis, C. David; Berger, Shelley L.

doi:10.1093/emboj/16.3.555

Cited by 195 publications

(175 citation statements)

References 67 publications

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“…Previous studies demonstrated that fusion of GCN5 to the bacterial LexA DNA-binding domain activated transcription in yeast. It was suggested that this activity was attributable to the HAT and ADA2 binding domains of GCN5 (44). In line with the previous studies, transfection of pBIND-GCN5 into 293T or U2OS cells activated the pG5luc luciferase reporter in a GCN5-dependent manner (Fig.…”

Section: B23 In Gcn5-dependent Histone Acetylation and Transactivationsupporting

confidence: 86%

Nucleophosmin/B23 Negatively Regulates GCN5-dependent Histone Acetylation and Transactivation

Zou

Giannone

et al. 2008

Journal of Biological Chemistry

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Nucleophosmin/B23 is a multifunctional phosphoprotein that is overexpressed in cancer cells and has been shown to be involved in both positive and negative regulation of transcription. In this study, we first identified GCN5 acetyltransferase as a B23-interacting protein by mass spectrometry, which was then confirmed by in vivo co-immunoprecipitation. An in vitro assay demonstrated that B23 bound the PCAF-N domain of GCN5 and inhibited GCN5-mediated acetylation of both free and mononucleosomal histones, probably through interfering with GCN5 and masking histones from being acetylated. Mitotic B23 exhibited higher inhibitory activity on GCN5-mediated histone acetylation than interphase B23. Immunodepletion experiments of mitotic extracts revealed that phosphorylation of B23 at Thr 199 enhanced the inhibition of GCN5-mediated histone acetylation. Moreover, luciferase reporter and microarray analyses suggested that B23 attenuated GCN5-mediated transactivation in vivo. Taken together, our studies suggest a molecular mechanism of B23 in the mitotic inhibition of GCN5-mediated histone acetylation and transactivation.The acetylation of nucleosomal histones by histone acetyltransferases (HATs) 5 has been known for several decades. Histone-modifying enzymes, such as GCN5 (general control of amino acid synthesis 5) in the Spt-Ada-Gcn5 acetyltransferase (SAGA) and Esa1p in the NuA4 complex, can acetylate specific lysine residues in histone N-terminal tails (1). According to the histone code hypothesis (2), site-specific acetylation of histone tails may trigger chromatin remodeling that leads to retention of effector proteins to active promoters and formation of transcriptionally active chromatin regions.GCN5 was originally identified as a transcriptional coactivator in yeast and was proposed to contribute to transcription by establishing interactions between certain activators and transcriptional complexes (3). GCN5 enhances transcription through its intrinsic acetyltransferase activity (4), which facilitates acetylation of histones and nonhistone substrates (3). Recruitment of the SAGA complex greatly increases transcriptional activation in vitro (5), and the requirement of GCN5 for chromatin remodeling has been demonstrated in vivo (6). However, the mechanism(s) that regulates GCN5 activity particularly in the context of histone acetylation has yet to be examined in detail. Potentially, GCN5 HAT activity can be regulated through posttranslational modifications, interacting with other proteins or at the level of substrate modifications. For example, phosphorylation by the Ku-DNA-dependent protein kinase or sumoylation may regulate GCN5-HAT activity (7,8). Also, interaction with the SANT domain of the Ada2 affects GCN5-HAT activity in yeast (9). Likewise, modification of substrates, such as phosphorylation of H3 serine 10, increases GCN5 acetylation activity toward lysine 14 of H3 (10, 11).Nucleophosmin/B23, also known as NPM1, NO38, or numatrin, has been identified as a phosphoprotein that possesses multiple cellular func...

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Section: B23 In Gcn5-dependent Histone Acetylation and Transactivationsupporting

confidence: 86%

Nucleophosmin/B23 Negatively Regulates GCN5-dependent Histone Acetylation and Transactivation

Zou

Giannone

et al. 2008

Journal of Biological Chemistry

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“…Purified ADA and SAGA complexes both have been shown to contain the non-DNA-binding, transcriptional adaptor proteins Ada2p and Ada3p (8 -10). Consistent with these in vitro results, genetic experiments in yeast have documented that mutations in Ada2p or Ada3p yield phenotypes identical to loss of Gcn5p in terms of both transcriptional regulation at specific gene loci (11,12) and cell growth (11,13). In addition, several specific proteins have recently been identified as unique components of ADA or SAGA.…”

mentioning

confidence: 53%

The Yeast Histone Acetyltransferase A2 Complex, but Not Free Gcn5p, Binds Stably to Nucleosomal Arrays

Sendra

Tse

Hansen

2000

Journal of Biological Chemistry

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We have investigated the structural basis for the differential catalytic function of the yeast Gcn5p-containing histone acetyltransferase (HAT) A2 complex and free recombinant yeast Gcn5p (rGcn5p). HAT A2 is shown to be a unique complex that contains Gcn5p, Ada2p, and Ada3p, but not proteins specific to other related HAT A complexes, e.g. ADA, SAGA. Nevertheless, HAT A2 produces the same unique polyacetylation pattern of nucleosomal substrates reported previously for ADA and SAGA, demonstrating that proteins specific to the ADA and SAGA complexes do not influence the enzymatic activity of Gcn5p within the HAT A2 complex. To investigate the role of substrate interactions in the differential behavior of free and complexed Gcn5p, sucrose density gradient centrifugation was used to characterize the binding of HAT A2 and free rGcn5p to intact and trypsinized nucleosomal arrays, H3/H4 tetramer arrays, and nucleosome core particles. We find that HAT A2 forms stable complexes with all nucleosomal substrates tested. In distinct contrast, rGcn5p does not interact stably with nucleosomal arrays, despite being able to specifically monoacetylate the H3 N terminus of nucleosomal substrates. Our data suggest that the ability of the HAT A2 complex to bind stably to nucleosomal arrays is functionally related to both local and global acetylation by the complexed and free forms of Gcn5p.Histone acetylation is a dynamic process in vivo involving multiple acetyltransferase and deacetylase enzymes (1-3). Acetylation occurs at specific lysine residues of each of the core histone N termini, and influences chromatin structure and function at all levels from the folded chromatin fiber to the nucleosome (4 -6). Because of the key role of acetylation in transcription and replication, a great deal of attention has been focused on the properties and functions of recently identified histone acetyltransferase enzymes (HATs).1 HAT A enzymes (e.g. Gcn5p, Esa1p) primarily are involved in transcriptional regulation, whereas HAT B enzymes (e.g. Hat1p) are thought to participate in replication coupled-chromatin assembly. The Tetrahymena equivalent of yeast Gcn5p (Gcn5p) was the first specific HAT A enzyme to be cloned and overexpressed (7), and the Gcn5 family of HATs remains the focus of intense investigation (see Refs. 5,8,and 9, and references therein).The catalytic function of yeast Gcn5p in vitro is strongly dependent on whether the enzyme is free or is a component of large multiprotein complexes such as HAT A2, ADA, and SAGA (8, 9). Purified ADA and SAGA complexes both have been shown to contain the non-DNA-binding, transcriptional adaptor proteins Ada2p and Ada3p (8 -10). Consistent with these in vitro results, genetic experiments in yeast have documented that mutations in Ada2p or Ada3p yield phenotypes identical to loss of Gcn5p in terms of both transcriptional regulation at specific gene loci (11, 12) and cell growth (11, 13). In addition, several specific proteins have recently been identified as unique components of ADA or SAGA. For exam...

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“…The catalytic domain of the Gcn5 HAT is required for coactivator function in vivo, providing a genetic link between histone modification and transcriptional activation (23). As a human GCN5 homolog has been identified, this HAT is likely to be widely conserved (24,25).…”

Section: Tetrahymena Histone Acetyltransferase a And Yeast Gcn5mentioning

confidence: 99%

“…However, unlike the native HAT A enzyme, recombinant Gcn5 cannot acetylate nucleosomal histones, implying that other subunits in the complex must influence its activity on chromatin. Genetic and biochemical studies reveal at least two interacting proteins, Ada2 and Ada3, that form a complex with Gcn5 (23,(27)(28)(29). Binding of Ada2 to the activation domains of the transcriptional activators VP16 and Gcn4 in vitro suggests a mechanism by which promoter targeting of Gcn5 might be achieved (30,31).…”

Section: Tetrahymena Histone Acetyltransferase a And Yeast Gcn5mentioning

confidence: 99%

Chromatin Remodeling and the Control of Gene Expression

1997

Journal of Biological Chemistry

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Histone acetyltransferase activity and interaction with ADA2 are critical for GCN5 function invivo

Cited by 195 publications

References 67 publications

Nucleophosmin/B23 Negatively Regulates GCN5-dependent Histone Acetylation and Transactivation

Nucleophosmin/B23 Negatively Regulates GCN5-dependent Histone Acetylation and Transactivation

The Yeast Histone Acetyltransferase A2 Complex, but Not Free Gcn5p, Binds Stably to Nucleosomal Arrays

Chromatin Remodeling and the Control of Gene Expression

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