Structural studies with coactivators for the estrogen receptor

Abstract

Coactivators play essential roles in nuclear receptor-mediated gene transcription. To date, a variety of coactivators have been identified. They can be scaffolding proteins, chromatin remodelers, posttranslational modification enzymes, or RNA splicing factors. Different coactivators are recruited to a nuclear receptor to form large protein complexes at different stages of transcription, and they often act synergistically. Structural analyses on these coactivators and their complex formation with nuclear receptors provide valuable information on understanding nuclear receptor-mediated gene regulation. Here we review recent structural studies on three well-documented nuclear receptor coactivators: steroid receptor coactivators (SRCs), CBP/p300, and CARM1, and their assembly into active DNA-bound estrogen receptor/coactivator complexes for initiation and for the subsequent step of elongation. This review specifically emphasizes the structural interaction within the estrogen receptor (ER) coactivator complex.