Reciprocal Recruitment of DRIP/Mediator and p160 Coactivator Complexes in Vivo by Estrogen Receptor

Darya Burakov,Linda A Crofts,Chao-Pei Betty Chang,Leonard P Freedman

doi:10.1074/jbc.c200099200

Darya Burakov, Linda A Crofts + Show 2 more

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https://doi.org/10.1074/jbc.c200099200

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Abstract

Two functionally distinct classes of coactivators are recruited by liganded estrogen receptor, the DRIP/Mediator complex and p160 proteins, although the relative dynamics of recruitment is unclear. Previously, we have shown a direct, estradiol-dependent interaction between the DRIP205 subunit of the DRIP complex and the estrogen receptor (ER) AF2 domain. Here we demonstrate the in vivo recruitment of other endogenous DRIP subunits to ER in response to estradiol treatment in MCF-7 cells. To explore the relationship between DRIP and p160 coactivators, we examined the kinetics of coactivator recruitment to the ER target promoter, pS2, by chromatin immunoprecipitation. We observed a cyclic association and dissociation of coactivators with the promoter, with recruitment of p160s and DRIPs occurring in opposite phases, suggesting an exchange between these coactivator complexes at the target promoter.

Highlights

From the Cell Biology Program, Memorial SloanKettering Cancer Center, Sloan-Kettering Division, Joan and Sanford I
To explore the relationship between DRIP and p160 coactivators, we examined the kinetics of coactivator recruitment to the estrogen receptor (ER) target promoter, pS2, by chromatin immunoprecipitation
Using chromatin immunoprecipitation (ChIP), we have examined the kinetics of coactivator recruitment to an endogenous estrogen-regulated promoter

Summary

Introduction

From the Cell Biology Program, Memorial SloanKettering Cancer Center, Sloan-Kettering Division, Joan and Sanford I. Two functionally distinct classes of coactivators are recruited by liganded estrogen receptor, the DRIP/Mediator complex and p160 proteins, the relative dynamics of recruitment is unclear. A second distinct class of coactivators, alternatively called DRIP, ARC, or TRAP [4, 5], comprises a multi-protein complex that interacts with liganded nuclear receptors, including ER␣ and ER␤, via the DRIP205/ TRAP220 subunit (6 –10).

Results

Conclusion