Ubiquitin Specific Peptidase 21 (USP21)

USP21 encodes a member of the C19 peptidase family, also known as family 2 of ubiquitin carboxy-terminal hydrolases. The encoded protein cleaves ubiquitin from ubiquitinated proteins for recycling in intracellular protein degradation. The encoded protein is also able to release NEDD8, a ubiquitin-like protein, from NEDD8-conjugated proteins. This gene has been referred to as USP16 and USP23 but is now known as USP21. Alternatively spliced transcript variants have been described.The sequence contains all 8 motifs characteristic of USPs, including a conserved cysteine and 2 conserved histidines at the putative active site. Northern blot analysis detected variable expression of an approximately 2.2-kb transcript in all tissues examined, with highest expression in heart, pancreas, and skeletal muscle.