MYSM1 is required for full activation of several transcriptional events, including androgen receptor (AR)-regulated target genes in prostate cancer cells. It is part of a regulatory protein complex with the histone acetyltransferase EP300 (p300) and KAT2B (CBP-associated factor (p/CAF)), regulating transcriptional initiation and elongaion by coordinating histone acetylation, H2A deubiquitination and linker histone dissociation. MYSM1 preferentially deubiquitinates H2A in hyperacetylated nucleosomes (Zhu et al. 2007).
thiol-dependent ubiquitin-specific protease activity of MYSM1:EP300:KAT2B:Ub-histone H2A [nucleoplasm]