module: dmel_gcn5_acetyltransferase_complexes
title: Gcn5-containing histone acetyltransferase complexes in Drosophila melanogaster
label: Gcn5 acetyltransferase complexes
module_type: PROTEIN_COMPLEX
description: >-
  The histone acetyltransferase Gcn5 acetylates histone H3 as the catalytic
  subunit of several coactivator complexes. Gcn5 always sits in a HAT module
  with Ada3, Sgf29 and an Ada2 paralog. With Ada2b it forms part of SAGA, a
  large coactivator that also contains a TBP-interacting core, the Tra1
  homolog Nipped-A, and a deubiquitinase module that removes ubiquitin from
  histone H2B through the protease Nonstop. With Ada2a it forms ATAC, which
  also contains the Atac1-3 subunits. Smaller ADA and CHAT (Chiffon-containing)
  complexes contain only the HAT module, with Chiffon in CHAT.
summary: >-
  SAGA, ATAC, ADA and CHAT coactivator complexes that share the Gcn5
  histone acetyltransferase module.
concepts:
  - {id: GO:0000123, label: histone acetyltransferase complex}
cellular_components:
  - {id: GO:0000785, label: chromatin}
variant_sets:
  - id: gcn5_complexes
    label: Gcn5-containing complexes
    selection: ONE_OR_MORE
    variants:
      - id: saga
        label: SAGA complex
        complex_term: {id: GO:0000124, label: SAGA complex}
        parts:
          - id: saga_hat_module
            label: SAGA HAT module
            role: histone H3 acetylation
            genes: [Gcn5, Ada2b, Ada3, Sgf29]
            unit_functions:
              Gcn5: {id: GO:0004402, label: histone acetyltransferase activity}
          - id: saga_dub_module
            label: SAGA deubiquitinase module
            role: histone H2B deubiquitylation
            genes: [not, Sgf11, e(y)2, Atxn7]
            complex_term: {id: GO:0071819, label: DUBm complex}
            unit_functions:
              not: {id: GO:0140936, label: histone H2B deubiquitinase activity}
          - id: saga_core_module
            label: SAGA core module
            role: structural core and TBP interaction
            genes: [Taf9, Taf10b, Taf12, Saf6, Spt3, Spt7, Spt20, Ada1-1, Ada1-2, wda]
          - id: saga_tra1
            label: Nipped-A (Tra1)
            role: activator-interacting subunit
            genes: [Nipped-A]
          - id: saga_splicing_factors
            label: SF3B subunits associated with SAGA
            role: splicing-factor subunits
            genes: [Sf3b3, Sf3b5]
      - id: atac
        label: ATAC complex
        group: ATAC
        complex_term: {id: GO:0140672, label: ATAC complex}
        unit_functions:
          Gcn5: {id: GO:0004402, label: histone acetyltransferase activity}
      - id: ada
        label: ADA complex
        group: ADAC
        complex_term: {id: GO:0140671, label: ADA complex}
        unit_functions:
          Gcn5: {id: GO:0004402, label: histone acetyltransferase activity}
      - id: chat
        label: CHAT complex
        group: CHAT
        unit_functions:
          Gcn5: {id: GO:0004402, label: histone acetyltransferase activity}
notes: >-
  The four FlyBase subgroups are modelled as alternative complexes, so shared
  HAT-module subunits appear in each. SAGA is decomposed into its HAT,
  deubiquitinase, core, Tra1 and SF3B parts; within the core, assignment of the
  two Ada1 paralogs and Wda follows their FlyBase membership of SAGA and is not
  meant to resolve finer architecture. ATAC also contains Hcf, Wds, Chrac-14,
  NC2beta and Mocs2B as listed by FlyBase.