TRIAD1 inhibits MDM2-mediated p53 ubiquitination and degradation

► TRIAD1 is required for p53 activation and stabilization. ► TRIAD1 antagonizes MDM2-mediated p53 degradation. ► TRIAD1 inhibits the interaction between p53 and MDM2. ► TRIAD1 interacts with the C-terminus of p53. ► TRIAD1 negatively regulates MDM2 function by p53-mediated cell growth suppression.