Estrogen receptors recruit SMRT and N-CoR corepressors through newly recognized contacts between the corepressor N terminus and the receptor DNA binding domain.
Estrogen receptors (ERs) are hormone-regulated transcription factors that regulate key aspects of reproduction and development. ERs are unusual in that they do not typically repress transcription in the absence of hormone but instead possess otherwise cryptic repressive functions that are revealed upon binding to certain hormone antagonists. The roles of corepressors in the control of these aspects of ER function are complex and incompletely understood. We report here that ERs recruit SMRT through an unusual mode of interaction involving multiple contact surfaces. Two surfaces of SMRT, located at the N- and C-terminal domains, contribute to the recruitment of the corepressor to ERs in vitro and are crucial for the corepressor modulation of ER transcriptional activity in cells. These corepressor surfaces contact the DNA binding domain of the receptor, rather than the hormone binding domain previously elucidated for other corepressor/nuclear receptor interactions, and are modulated by the ER's recognition of cognate DNA binding sites. Several additional nuclear receptors, and at least one other corepressor, N-CoR, share aspects of this novel mode of corepressor recruitment. Our results highlight a molecular mechanism that helps explain several previously paradoxical aspects of ER-mediated transcriptional antagonism, which may have a broader significance for an understanding of target gene repression by other nuclear receptors.
Varlakhanova
Natalia
N
Department of Microbiology, College of Biological Sciences, University of California at Davis, Davis, California 95616, USA.
Snyder
Chelsea
C
Jose
Soumia
S
Hahm
Johnnie B
JB
Privalsky
Martin L
ML
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D004247:DNA / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D056971:Nuclear Receptor Co-Repressor 1 / Q000737:chemistry* / Q000378:metabolism*; D056985:Nuclear Receptor Co-Repressor 2 / Q000737:chemistry* / Q000378:metabolism*; D047493:PPAR alpha / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D000099150:Receptor, Farnesoid X-Activated
D004247:DNA; D004958:Estradiol; D047628:Estrogen Receptor alpha; D008024:Ligands; D056971:Nuclear Receptor Co-Repressor 1; D056985:Nuclear Receptor Co-Repressor 2; D047493:PPAR alpha; D018160:Receptors, Cytoplasmic and Nuclear; D011988:Receptors, Thyroid Hormone; D000099150:Receptor, Farnesoid X-Activated