Deubiquitinating enzyme that plays a role in behavior, possibly by regulating GABA action. May act by mediating the deubiquitination of GAD1/GAD67 (By similarity). Has almost no deubiquitinating activity by itself and requires the interaction with WDR48 to have a high activity (PubMed:19075014, PubMed:26388029). Not involved in deubiquitination of monoubiquitinated FANCD2 (PubMed:19075014). 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). Activated by interaction with WDR48. Interacts with WDR48 (PubMed:19075014, PubMed:26388029). Interacts with WDR20 (PubMed:20147737). Broadly expressed. Belongs to the peptidase C19 family. USP12/USP46 subfamily.