TRIAD1 is negatively regulated by the MDM2 E3 ligase

Abstract

Two RING fingers and DRIL1 (TRIAD1) is a proapoptotic protein that promotes p53 activation in several cancer cell lines, including MCF7, U2OS and A549 cells. In this study, we demonstrated that TRIAD1 is a novel ubiquitination target for proteasome-dependent degradation by murine double minute 2 (MDM2). TRIAD1 was found to interact with and be ubiquitinated by MDM2. RNA interference against MDM2 increased endogenous TRIAD1 protein stability. The functional study results suggested that TRIAD1 degradation by MDM2 suppresses TRIAD1-mediated cell growth. These data suggested a novel negative regulatory mechanism of TRIAD1 via MDM2 E3 ligase ubiquitination.