The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Joan W. Conaway - One of the best experts on this subject based on the ideXlab platform.

  • identification of new subunits of the multiprotein mammalian trrap tip60 containing Histone Acetyltransferase complex
    Journal of Biological Chemistry, 2003
    Co-Authors: Yong Cai, Jingji Jin, Shigeo Sato, Irina Sorokina, Tari Parmely, Ronald C. Conaway, Joan W. Conaway, Chieri Tomomorisato
    Abstract:

    The mammalian ATM/PI 3-kinase-related TRRAP protein was previously found to be a component of a multi-protein Histone Acetyltransferase (HAT) complex containing the HAT TIP60. In this report, we identify a previously uncharacterized protein encoded by the FLJ10914 ORF, which we designate MRGBP, as a new component of the TRRAP/TIP60 HAT complex. In addition, through purification of MRGBP and its associated proteins from HeLa cell nuclear extracts, we identify the thyroid receptor coactivating protein (TRCp120), DMAP1, and the related MRG15 and MRGX proteins as MRGBP-associating proteins, and we present biochemical evidence that they are previously unrecognized components of the TRRAP/TIP60 HAT complex. Taken together, our findings shed new light on the structure and function of the mammalian TRRAP/TIP60 Histone Acetyltransferase complex.

  • Identification of new subunits of the multiprotein mammalian TRRAP/TIP60-containing Histone Acetyltransferase complex.
    The Journal of biological chemistry, 2003
    Co-Authors: Yong Cai, Jingji Jin, Chieri Tomomori-sato, Shigeo Sato, Irina Sorokina, Tari Parmely, Ronald C. Conaway, Joan W. Conaway
    Abstract:

    The mammalian ATM/PI 3-kinase-related TRRAP protein was previously found to be a component of a multi-protein Histone Acetyltransferase (HAT) complex containing the HAT TIP60. In this report, we identify a previously uncharacterized protein encoded by the FLJ10914 ORF, which we designate MRGBP, as a new component of the TRRAP/TIP60 HAT complex. In addition, through purification of MRGBP and its associated proteins from HeLa cell nuclear extracts, we identify the thyroid receptor coactivating protein (TRCp120), DMAP1, and the related MRG15 and MRGX proteins as MRGBP-associating proteins, and we present biochemical evidence that they are previously unrecognized components of the TRRAP/TIP60 HAT complex. Taken together, our findings shed new light on the structure and function of the mammalian TRRAP/TIP60 Histone Acetyltransferase complex.

Song Tan - One of the best experts on this subject based on the ideXlab platform.

  • The Ada2/Ada3/Gcn5/Sgf29 Histone Acetyltransferase module.
    Biochimica et biophysica acta. Gene regulatory mechanisms, 2020
    Co-Authors: Jose M. Espinola-lopez, Song Tan
    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.

  • The Saccharomyces cerevisiae Piccolo NuA4 Histone Acetyltransferase complex requires the Enhancer of Polycomb A domain and chromodomain to acetylate nucleosomes.
    Molecular and cellular biology, 2005
    Co-Authors: William Selleck, Israel Fortin, Decha Sermwittayawong, Jacques Côté, Song Tan
    Abstract:

    Chromatin modification complexes are key gene regulatory factors which posttranslationally modify the Histone component of chromatin with epigenetic marks. To address what features of chromatin modification complexes are responsible for the specific recognition of nucleosomes compared to naked Histones, we have performed a functional dissection of the Esa1-containing Saccharomyces cerevisiae Piccolo NuA4 Histone Acetyltransferase complex. Our studies define the Piccolo determinants sufficient to assemble its three subunits into a complex as well as Piccolo determinants sufficient to specifically acetylate a chromatin template. We find that the conserved Enhancer of Polycomb A (EPcA) homology region of the Epl1 component and the N-terminal 165 amino acids of the Yng2 component of Piccolo are sufficient with Esa1 to specifically act on nucleosomes. We also find that the Esa1 chromodomain plays a critical role in Piccolo's ability to distinguish between Histones and nucleosomes. In particular, specific point mutations in the chromodomain putative hydrophobic cage which strongly hinder growth in yeast greatly reduce Histone Acetyltransferase activity on nucleosome substrates, independent of Histone methylation or other modifications. However, the chromodomain is not required for Piccolo to bind to nucleosomes, suggesting a role for the chromodomain in a catalysis step after nucleosome binding.

William Selleck - One of the best experts on this subject based on the ideXlab platform.

  • Structure and nucleosome interaction of the yeast NuA4 and Piccolo–NuA4 Histone Acetyltransferase complexes
    Nature Structural & Molecular Biology, 2011
    Co-Authors: Johnathan R Chittuluru, William Selleck, Michael J. Carrozza, Rhea T. Utley, Yuriy Chaban, Julie Monnet-saksouk, Vasileia Sapountzi, Jiehuan Huang, Myriam Cramet, Stephane Allard
    Abstract:

    NuA4 is an essential and conserved Histone Acetyltransferase (HAT) complex. Using electron microscopy supported by biochemical analyses, insights are now gained into its interaction with the nucleosome core particle (NCP). These data indicate that the Epl1 subunit is essential for NCP interaction, whereas the Yng2 subunit positions the Acetyltransferase complex relative to specific Histone tails. We have used EM and biochemistry to characterize the structure of NuA4, an essential yeast Histone Acetyltransferase (HAT) complex conserved throughout eukaryotes, and we have determined the interaction of NuA4 with the nucleosome core particle (NCP). The ATM-related Tra1 subunit, which is shared with the SAGA coactivator complex, forms a large domain joined to a second region that accommodates the catalytic subcomplex Piccolo and other NuA4 subunits. EM analysis of a NuA4–NCP complex shows the NCP bound at the periphery of NuA4. EM characterization of Piccolo and Piccolo–NCP provided further information about subunit organization and confirmed that Histone acetylation requires minimal contact with the NCP. A small conserved region at the N terminus of Piccolo subunit enhancer of Polycomb-like 1 (Epl1) is essential for NCP interaction, whereas the subunit yeast homolog of mammalian Ing1 2 (Yng2) apparently positions Piccolo for efficient acetylation of Histone H4 or Histone H2A tails. Taken together, these results provide an understanding of the NuA4 subunit organization and the NuA4–NCP interactions.

  • The Saccharomyces cerevisiae Piccolo NuA4 Histone Acetyltransferase complex requires the Enhancer of Polycomb A domain and chromodomain to acetylate nucleosomes.
    Molecular and cellular biology, 2005
    Co-Authors: William Selleck, Israel Fortin, Decha Sermwittayawong, Jacques Côté, Song Tan
    Abstract:

    Chromatin modification complexes are key gene regulatory factors which posttranslationally modify the Histone component of chromatin with epigenetic marks. To address what features of chromatin modification complexes are responsible for the specific recognition of nucleosomes compared to naked Histones, we have performed a functional dissection of the Esa1-containing Saccharomyces cerevisiae Piccolo NuA4 Histone Acetyltransferase complex. Our studies define the Piccolo determinants sufficient to assemble its three subunits into a complex as well as Piccolo determinants sufficient to specifically acetylate a chromatin template. We find that the conserved Enhancer of Polycomb A (EPcA) homology region of the Epl1 component and the N-terminal 165 amino acids of the Yng2 component of Piccolo are sufficient with Esa1 to specifically act on nucleosomes. We also find that the Esa1 chromodomain plays a critical role in Piccolo's ability to distinguish between Histones and nucleosomes. In particular, specific point mutations in the chromodomain putative hydrophobic cage which strongly hinder growth in yeast greatly reduce Histone Acetyltransferase activity on nucleosome substrates, independent of Histone methylation or other modifications. However, the chromodomain is not required for Piccolo to bind to nucleosomes, suggesting a role for the chromodomain in a catalysis step after nucleosome binding.

Stephane Allard - One of the best experts on this subject based on the ideXlab platform.

  • Structure and nucleosome interaction of the yeast NuA4 and Piccolo–NuA4 Histone Acetyltransferase complexes
    Nature Structural & Molecular Biology, 2011
    Co-Authors: Johnathan R Chittuluru, William Selleck, Michael J. Carrozza, Rhea T. Utley, Yuriy Chaban, Julie Monnet-saksouk, Vasileia Sapountzi, Jiehuan Huang, Myriam Cramet, Stephane Allard
    Abstract:

    NuA4 is an essential and conserved Histone Acetyltransferase (HAT) complex. Using electron microscopy supported by biochemical analyses, insights are now gained into its interaction with the nucleosome core particle (NCP). These data indicate that the Epl1 subunit is essential for NCP interaction, whereas the Yng2 subunit positions the Acetyltransferase complex relative to specific Histone tails. We have used EM and biochemistry to characterize the structure of NuA4, an essential yeast Histone Acetyltransferase (HAT) complex conserved throughout eukaryotes, and we have determined the interaction of NuA4 with the nucleosome core particle (NCP). The ATM-related Tra1 subunit, which is shared with the SAGA coactivator complex, forms a large domain joined to a second region that accommodates the catalytic subcomplex Piccolo and other NuA4 subunits. EM analysis of a NuA4–NCP complex shows the NCP bound at the periphery of NuA4. EM characterization of Piccolo and Piccolo–NCP provided further information about subunit organization and confirmed that Histone acetylation requires minimal contact with the NCP. A small conserved region at the N terminus of Piccolo subunit enhancer of Polycomb-like 1 (Epl1) is essential for NCP interaction, whereas the subunit yeast homolog of mammalian Ing1 2 (Yng2) apparently positions Piccolo for efficient acetylation of Histone H4 or Histone H2A tails. Taken together, these results provide an understanding of the NuA4 subunit organization and the NuA4–NCP interactions.

Saadi Khochbin - One of the best experts on this subject based on the ideXlab platform.

  • CONTROL OF THE Histone-Acetyltransferase ACTIVITY OF TIP60 BY THE HIV-1 TRANSACTIVATOR PROTEIN, TAT
    Biochemistry, 1999
    Co-Authors: Martina Creaven, Fabienne Hans, Vesco Mutskov, Stefan Dimitrov, Cecile Caron, Saadi Khochbin
    Abstract:

    Tip60, a cellular Histone-Acetyltransferase, is known to interact with the HIV-1-encoded transactivator protein, Tat. In this work, we show that the interaction of Tat with Tip60 efficiently inhibits the Tip60 Histone-Acetyltransferase activity. Besides its Histone-Acetyltransferase activity, Tip60 can undergo an autoacetylation which is not affected by Tat interaction. Our data show that Tip60 does not significantly influence Tat-dependent transcriptional activation of the 5'-LTR of HIV, suggesting that its interaction with Tat affects some intrinsic cellular process. We were then able to identify a cellular gene, Mn-dependent superoxide dismutase (Mn-SOD), that has a Tip60-dependent transcriptional activity. Interestingly, the simultaneous expression of Tat and Tip60 abolishes the effect of Tip60 on the activity of the Mn-SOD promoter. We postulate that the HIV-1 transactivator, Tat, in targeting Tip60 hinders the expression of cellular genes (such as Mn-SOD) which normally interfere with the efficient replication and propagation of the virus.