Ubiquitin Specific Peptidase 40 (USP40)

Modification of cellular proteins by ubiquitin is an essential regulatory mechanism controlled by the coordinated action of multiple ubiquitin-conjugating and deubiquitinating enzymes. USP40 belongs to a large family of cysteine proteases that function as deubiquitinating enzymes.By searching databases for sequences similar to USP family members, followed by PCR of human cDNA libraries, Quesada et al. (2004) cloned USP40. The deduced protein has a catalytic domain containing the cys box, QQD box, and his box characteristic of USP enzymes. Northern blot analysis detected variable expression in all tissues examined. The International Radiation Hybrid Mapping Consortium mapped the USP40 gene to chromosome 2.