Transcription cofactor (PubMed:30097457). Negatively regulates transcription activation by catenin beta-1 CTNNB1, perhaps acting by competing with TCF4 for CTNNB1 binding (PubMed:30097457). May play a role in DNA-damage response signaling (PubMed:33924684). Binds specifically to DNA sequences at peri-centromeric chromatin loci.