The protein encoded by this gene is a member of the large ubiquitin specific protease (Usp) family of proteins. These proteins are known to cleave ubiquitin, and contain a conserved cysteine residue (Cys box) and two conserved histidine residues (His box) that are thought to form part of the active site of the protease. This protein has been shown to cleave both the ubiquitin-proline and the ubiquitin-methionine bonds in vitro. This protein is thought to regulate many cellular processes through its deubiquitination activity, including the transforming growth factor beta (TGF-beta) pathway. Cardiac-specific overexpression of the human ortholog of this gene in mice causes enlargement of the heart that is more pronounced in the atrium than in the ventricle. This gene has two pseudogenes on chromosome 14. Alternative splicing results in multiple transcript variants that encode multiple protein isoforms.[provided by RefSeq, Aug 2014]