Involved in the ubiquitin-dependent proteolytic pathway in conjunction with the 26S proteasome. Deubiquitinates the androgen receptor and regulates the androgen receptor signaling pathway. 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). Interacts with AR. Belongs to the peptidase C19 family.