Deubiquitinating enzyme that plays a key role in chromatin by mediating deubiquitination of histone H2A and HCFC1. Catalytic component of the PR-DUB complex, a complex that specifically mediates deubiquitination of histone H2A monoubiquitinated at 'Lys-119' (H2AK119ub1). Does not deubiquitinate monoubiquitinated histone H2B. 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. Deubiquitination of HCFC1 does not lead to increase stability of HCFC1. Interferes with the BRCA1 and BARD1 heterodimer activity by inhibiting their ability to mediate ubiquitination and autoubiquitination. It however does not mediate deubiquitination of BRCA1 and BARD1. Acts as a tumor suppressor. Component of the PR-DUB complex, at least composed of BAP1 and ASXL1. Interacts with BRCA1 (via the RING finger). Interacts (via HBM-like motif) with HCFC1. Highly expressed in testis, placenta and ovary. Expressed in breast. Belongs to the peptidase C12 family. BAP1 subfamily. Note: This description may include information from UniProtKB.