Structural and Functional Impacts of ER Coactivator Sequential Recruitment

Mol Cell. 2017 Sep 7;67(5):733-743.e4. doi: 10.1016/j.molcel.2017.07.026. Epub 2017 Aug 24.


Nuclear receptors recruit multiple coactivators sequentially to activate transcription. This "ordered" recruitment allows different coactivator activities to engage the nuclear receptor complex at different steps of transcription. Estrogen receptor (ER) recruits steroid receptor coactivator-3 (SRC-3) primary coactivator and secondary coactivators, p300/CBP and CARM1. CARM1 recruitment lags behind the binding of SRC-3 and p300 to ER. Combining cryo-electron microscopy (cryo-EM) structure analysis and biochemical approaches, we demonstrate that there is a close crosstalk between early- and late-recruited coactivators. The sequential recruitment of CARM1 not only adds a protein arginine methyltransferase activity to the ER-coactivator complex, it also alters the structural organization of the pre-existing ERE/ERα/SRC-3/p300 complex. It induces a p300 conformational change and significantly increases p300 HAT activity on histone H3K18 residues, which, in turn, promotes CARM1 methylation activity on H3R17 residues to enhance transcriptional activity. This study reveals a structural role for a coactivator sequential recruitment and biochemical process in ER-mediated transcription.

Keywords: CARM1; SRC-3; coactivator; cryo-EM structure; estrogen receptor; histone modification; p300; sequential recruitment.

MeSH terms

  • Acetylation
  • Binding Sites
  • CARD Signaling Adaptor Proteins / chemistry
  • CARD Signaling Adaptor Proteins / genetics
  • CARD Signaling Adaptor Proteins / metabolism*
  • Cryoelectron Microscopy
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • E1A-Associated p300 Protein / chemistry
  • E1A-Associated p300 Protein / genetics
  • E1A-Associated p300 Protein / metabolism*
  • Estrogen Receptor alpha / chemistry
  • Estrogen Receptor alpha / genetics
  • Estrogen Receptor alpha / metabolism*
  • Guanylate Cyclase / chemistry
  • Guanylate Cyclase / genetics
  • Guanylate Cyclase / metabolism*
  • HEK293 Cells
  • HeLa Cells
  • Histones / chemistry
  • Histones / metabolism
  • Humans
  • MCF-7 Cells
  • Methylation
  • Models, Molecular
  • Multiprotein Complexes
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Nuclear Receptor Coactivator 3 / chemistry
  • Nuclear Receptor Coactivator 3 / genetics
  • Nuclear Receptor Coactivator 3 / metabolism*
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Structure-Activity Relationship
  • Time Factors
  • Transcription Factors
  • Transcription, Genetic*
  • Transcriptional Activation
  • Transfection


  • CARD Signaling Adaptor Proteins
  • DNA-Binding Proteins
  • ESR1 protein, human
  • Estrogen Receptor alpha
  • GREB1 protein, human
  • Histones
  • Multiprotein Complexes
  • Neoplasm Proteins
  • TTF1 protein, human
  • Transcription Factors
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • NCOA3 protein, human
  • Nuclear Receptor Coactivator 3
  • CARD11 protein, human
  • Guanylate Cyclase