Molecular architecture of quartet MOZ/MORF histone acetyltransferase complexes

Mol Cell Biol. 2008 Nov;28(22):6828-43. doi: 10.1128/MCB.01297-08. Epub 2008 Sep 15.


The monocytic leukemia zinc finger protein MOZ and the related factor MORF form tetrameric complexes with ING5 (inhibitor of growth 5), EAF6 (Esa1-associated factor 6 ortholog), and the bromodomain-PHD finger protein BRPF1, -2, or -3. To gain new insights into the structure, function, and regulation of these complexes, we reconstituted them and performed various molecular analyses. We found that BRPF proteins bridge the association of MOZ and MORF with ING5 and EAF6. An N-terminal region of BRPF1 interacts with the acetyltransferases; the enhancer of polycomb (EPc) homology domain in the middle part binds to ING5 and EAF6. The association of BRPF1 with EAF6 is weak, but ING5 increases the affinity. These three proteins form a trimeric core that is conserved from Drosophila melanogaster to humans, although authentic orthologs of MOZ and MORF are absent in invertebrates. Deletion mapping studies revealed that the acetyltransferase domain of MOZ/MORF is sufficient for BRPF1 interaction. At the functional level, complex formation with BRPF1 and ING5 drastically stimulates the activity of the acetyltransferase domain in acetylation of nucleosomal histone H3 and free histones H3 and H4. An unstructured 18-residue region at the C-terminal end of the catalytic domain is required for BRPF1 interaction and may function as an "activation lid." Furthermore, BRPF1 enhances the transcriptional potential of MOZ and a leukemic MOZ-TIF2 fusion protein. These findings thus indicate that BRPF proteins play a key role in assembling and activating MOZ/MORF acetyltransferase complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Binding Sites
  • Cell Line
  • DNA-Binding Proteins
  • Histone Acetyltransferases / genetics
  • Histone Acetyltransferases / metabolism*
  • Humans
  • Multiprotein Complexes* / chemistry
  • Multiprotein Complexes* / metabolism
  • Mutation
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Protein Structure, Tertiary
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription, Genetic
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism


  • Adaptor Proteins, Signal Transducing
  • BRPF1 protein, human
  • DNA-Binding Proteins
  • ING5 protein, human
  • Multiprotein Complexes
  • Nuclear Proteins
  • Protein Subunits
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Tumor Suppressor Proteins
  • Histone Acetyltransferases
  • KAT6A protein, human
  • KAT6B protein, human