Hydrolase that can remove 'Lys-48'-linked conjugated ubiquitin from proteins. 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 COPS5. Widely expressed with high levels in heart, skeletal muscle, and kidney, and low levels in liver and brain (PubMed:12054670). Also expressed in lung (at protein level) (PubMed:21499297). Belongs to the MINDY deubiquitinase family. FAM188 subfamily. Was named CARP for 'CARD domain-containing protein' by PubMed:12054670. However, no CARD domain is detected by any prediction tool. Contaminating sequence. Potential poly-A sequence.