The TRAP/Mediator coactivator complex interacts directly with estrogen receptors alpha and beta through the TRAP220 subunit and directly enhances estrogen receptor function in vitro.
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Kang YK, Guermah M, Yuan CX, Roeder RG
The TRAP/Mediator coactivator complex interacts directly with estrogen receptors alpha and beta through the TRAP220 subunit and directly enhances estrogen receptor function in vitro.
Proc Natl Acad Sci U S A. 2002 Mar 5;99(5):2642-7. Epub 2002 Feb 26.
- PubMed ID
- 11867769 [ View in PubMed]
- Abstract
Target gene activation by nuclear hormone receptors, including estrogen receptors (ERs), is thought to be mediated by a variety of interacting cofactors. Here we identify a number of nuclear extract-derived proteins that interact with immobilized ER ligand binding domains in a 17beta-estradiol-dependent manner. The most prominent of these are components of the thyroid hormone receptor-associated protein (TRAP)/Mediator coactivator complex, which interacts with ERalpha and ERbeta in both unfractionated nuclear extracts and purified form. Studies with extracts from TRAP220(-/-) fibroblasts reveal that these interactions depend on TRAP220, a TRAP/Mediator subunit previously shown to interact with ER and other nuclear receptors in a ligand-dependent manner. The physiological relevance of the in vitro interaction is documented further by the isolation of an ERalpha-TRAP/Mediator complex from cultured cells expressing an epitope-tagged ERalpha. Finally, the complete TRAP/Mediator complex is shown to enhance ER function directly in a highly purified cell-free transcription system. These studies firmly establish a direct role for TRAP/Mediator, through TRAP220, in ER function.