Regulator which is able to repress transcription, possibly via its interaction with a multiprotein chromatin remodeling complex that modifies the chromatin (PubMed:14651845). Its interaction with BRCA2 suggests that it may play a central role in the DNA repair function of BRCA2 (PubMed:14651845). Mediates ligand-dependent transcriptional activation by nuclear hormone receptors (PubMed:19131338).