CSN5 (or c-Jun activation domain-binding protein1, JAB1) has been reported as the catalytic center for deneddylation of the Nedd8-cullin in the CSN complex that exists as monomer or a CSN5-containing small complex and plays various roles in HIF1-a stabilization, p27 nuclear export and degradation, E2F1-mediated apoptosis, cell cycle control, and cancer (Wei et al., 2008; Shackleford and Claret, 2010). Here, COPS5 is linked to cancer.