Metalloprotease that specifically deubiquitinates monoubiquitinated histone H2A, a specific tag for epigenetic transcriptional repression, thereby acting as a coactivator. Preferentially deubiquitinates monoubiquitinated H2A in hyperacetylated nucleosomes. Deubiquitination of histone H2A leads to facilitate the phosphorylation and dissociation of histone H1 from the nucleosome. Acts as a coactivator by participating in the initiation and elongation steps of androgen receptor (AR)-induced gene activation (By similarity). Binds double-stranded DNA via the SANT domain. The SWIRM domain does not bind double-stranded DNA (By similarity). Belongs to the peptidase M67A family. MYSM1 subfamily. Truncated N-terminus. Contaminating sequence. Potential poly-A sequence.