Ligand-dependent Formation of Retinoid Receptors, Receptor-interacting Protein 140 (RIP140), and Histone Deacetylase Complex Is Mediated by a Novel Receptor-interacting Motif of RIP140

Li-Na Wei,Maria Farooqui,Xinli Hu

doi:10.1074/jbc.m010185200

Abstract

Receptor-interacting protein 140 (RIP140) interacts with retinoic acid receptor and retinoid X receptor in a ligand-dependent manner and suppresses retinoic acid (RA) induction of its target genes. The receptor-interacting motif is mapped to a C-terminal peptide sequence (LTKTNPILYYMLQK) of RIP140. The functional role of this motif in mediating the suppressive effects of RIP140 on RA induction is demonstrated in mutation studies. RA induces coimmunoprecipitation of histone deacetylase 3 with retinoic acid receptor/retinoid X receptor in the presence of wild type RIP140, but not in the presence of the C-terminal motif-deleted RIP140. A decrease in histone acetylation on the promoter region that carries a RA response element is associated with the expression of wild type RIP140, but not with expression of the mutant RIP140, in a dose-dependent manner. These data provide a molecular explanation for RIP140 acting as a novel ligand-dependent, negative modulator of RA-regulated gene expression.

Highlights

Released, and coactivators are recruited to activate target gene expression
Two unique features of Receptor-interacting protein 140 (RIP140) are: (a) in contrast to classical coactivators that interact with ligand-bound hormone receptors to activate target gene expression, RIP140 suppressed gene activation by interacting with ligand-bound nuclear receptors in most reported studies (28 –31), and (b) the ligand-dependent receptorinteracting motif of RIP140 does not involve any of its nine copies of the LXXLL motif, rather it utilizes its C-terminal domain for holo-retinoic acid receptor (RAR)/retinoid X receptor (RXR) interaction and N-terminal amino acids (AA) 154 –350 for Ah receptor interaction [26, 32]
In Vivo Ligand-dependent RAR/RXR Interaction of RIP140 Detected by Two-hybrid Interaction Tests—Previously, we have confirmed that RIP140 interaction with RAR and RXR depends upon the presence of ligands and utilizes a small C-terminal segment of RIP140 that lacks a typical LXXLL motif [27]

Summary

Introduction

Released, and coactivators are recruited to activate target gene expression. One mechanism of gene activation is believed to be mediated by relaxation of chromatin due to the action of acetyltransferase encoded by the coactivator complexes. Association of HDAC3, RIP140, and RAR/RXR was demonstrated to be ligand-dependent in coimmunoprecipitation experiments, and histone acetylation decreased on the promoter region carrying a RA response element in the presence of RIP140.

Results

Conclusion