title: 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.
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.
authors.affiliation: Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10021, USA.
authors.forename: Yun Kyoung
authors.initials: YK
authors.lastname: Kang
authors.forename: Mohamed
authors.initials: M
authors.lastname: Guermah
authors.forename: Chao-Xing
authors.initials: CX
authors.lastname: Yuan
authors.forename: Robert G
authors.initials: RG
authors.lastname: Roeder
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002457:Cell Extracts; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D006367:HeLa Cells; D006801:Humans; D007424:Intracellular Fluid; D056913:Mediator Complex Subunit 1; D051379:Mice; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011988:Receptors, Thyroid Hormone / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: D002352:Carrier Proteins; D002457:Cell Extracts; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; C538855:MED1 protein, human; C538856:Med1 protein, mouse; D056913:Mediator Complex Subunit 1; D011960:Receptors, Estrogen; D011988:Receptors, Thyroid Hormone; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D004958:Estradiol