p63 is a cereblon substrate involved in thalidomide teratogenicity

Cereblon (CRBN) is a primary target of thalidomide and mediates its multiple pharmacological activities, including teratogenic and antimyeloma activities. CRBN functions as a substrate receptor of the E3 ubiquitin ligase CRL4, whose substrate specificity is modulated by thalidomide and its analogs. Although a number of CRL4 CRBN substrates have recently been identified, the substrate involved in thalidomide teratogenicity is unclear. Here we show that p63 isoforms are thalidomide-dependent CRL4 CRBN neosubstrates that are responsible, at least in part, for its teratogenic effects. The p53 family member p63 is associated with multiple developmental processes. ∆Np63α is essential for limb development, while TAp63α is important for cochlea development and hearing. Using a zebrafish model, we demonstrate that thalidomide exerts its teratogenic effects on pectoral fins and otic vesicles by inducing the degradation of ∆Np63α and TAp63α, respectively. These results may contribute to the invention of new thalidomide analogs lacking teratogenic activity. Zebrafish p63 isoforms were identified as thalidomide-dependent neosubstrates of the cereblon-containing E3 ligase complex. ∆Np63α and TAp63α are responsible for thalidomide-induced malformations of pectoral fins and otic vesicles, respectively.