Deubiquitinating enzyme that plays a key role in chromatin by mediating deubiquitination of histone H2A and HCFC1 (PubMed:12485996, PubMed:18757409, PubMed:20436459, PubMed:25451922). Catalytic component of the PR-DUB complex, a complex that specifically mediates deubiquitination of histone H2A monoubiquitinated at 'Lys-119' (H2AK119ub1) (PubMed:20436459, PubMed:25451922). Does not deubiquitinate monoubiquitinated histone H2B (PubMed:20436459). Acts as a regulator of cell growth by mediating deubiquitination of HCFC1 N-terminal and C-terminal chains, with some specificity toward 'Lys-48'-linked polyubiquitin chains compared to 'Lys-63'-linked polyubiquitin chains (PubMed:19188440, PubMed:19815555). Deubiquitination of HCFC1 does not lead to increase stability of HCFC1 (PubMed:19188440, PubMed:19815555). Interferes with the BRCA1 and BARD1 heterodimer activity by inhibiting their ability to mediate ubiquitination and autoubiquitination (PubMed:19117993). It however does not mediate deubiquitination of BRCA1 and BARD1 (PubMed:19117993). Able to mediate autodeubiquitination via intramolecular interactions to couteract monoubiquitination at the nuclear localization signal (NLS), thereby protecting it from cytoplasmic sequestration (PubMed:24703950). Acts as a tumor suppressor (PubMed:9528852). Thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal). Component of the PR-DUB complex, at least composed of BAP1 and ASXL1 (PubMed:20436459). Interacts with BRCA1 (via the RING finger) (PubMed:19117993, PubMed:9528852). Interacts (via HBM-like motif) with HCFC1 (PubMed:19188440, PubMed:19815555). Interacts (when phosphorylated at Thr-493) with FOXK1 (PubMed:25451922). Interacts (when phosphorylated at Thr-493) with FOXK2; leading to recruit the PR-DUB complex and repress FOXK2 target genes (PubMed:24748658, PubMed:25451922). Mainly nuclear. Binds to chromatin. Localizes to the cytoplasm when monoubiquitinated by the E2/E3 hybrid ubiquitin-protein ligase UBE2O (PubMed:24703950). Highly expressed in testis, placenta and ovary. Expressed in breast. Ubiquitinated: monoubiquitinated at multiple site of its nuclear localization signal (NLS) BY UBE2O, leading to cytoplasmic retention. Able to mediate autodeubiquitination via intramolecular interactions to couteract cytoplasmic retention. The gene represented in this entry is involved in disease pathogenesis. The disease is caused by variants affecting the gene represented in this entry. Belongs to the peptidase C12 family. BAP1 subfamily. According to a report, interaction with FOXK2 is not dependent on phosphorylation of BAP1 (PubMed:24748658). However, it was later shown that phosphorylation at Thr-493 promotes interaction with FOXK2 (PubMed:25451922). Extended N-terminus.