Deubiquitinating enzyme regulation of the p53 pathway: A lesson from Otub1

Figure 1 Diagram of the regulation of the p53 pathway by deubiquitinating enzymes. Arrows indicate activation and bars indicate inhibition. USP7, USP10, USP29, and USP42 deubiquitinate and activate p53, whereas USP2 destabilizes p53 by deubiquitinating MDM2 and MDMX and USP4 destabilizes p53 by deubiquitinating and stabilizing ARF-BP1. Otub1 stabilizes and activates p53 via non-canonical suppression of the MDM2 cognate E2 UbcH5, thereby inhibiting MDM2-mediated p53 ubiquitination and degradation. USP: Ubiquitin-specific protease