Ubiquitin Specific Peptidase 15 (USP15)

Ubiquitin , a highly conserved protein involved in the regulation of intracellular protein breakdown, cell cycle regulation, and stress response, is released from degraded proteins by disassembly of the polyubiquitin chains. The disassembly process is mediated by ubiquitin-specific proteases (USPs). By screening human brain cDNAs for those encoding proteins larger than 50 kD, Nagase et al. (1998) identified a partial cDNA encoding USP15, which they called KIAA0529. RT-PCR analysis detected USP15 expression in skeletal muscle, kidney, heart, placenta, liver, thymus, lung, and ovary, with little or no expression in other tissues. The 952-amino acid USP15 protein contains the conserved cysteine and histidine boxes present in all USPs. Like USP4, USP15 can cleave the ubiquitin-proline bond.