MDM2/HDM2: Proteins and Enzymes

MDM2 is a key regulator of p53 tumor suppressor protein activity and stability. MDM2 binds to and inhibits the transactivation domain of p53. In addition, MDM2 controls p53 stability by functioning as its E3 ligase in ubiquitination and by shuttling p53 from the nucleus to the cytoplasm for subsequent degradation. The importance of the p53/MDM2 relationship is underscored by the existence of an autoregulatory feedback loop whereby activated p53 transcriptionally upregulates the expression of its own inhibitor, MDM2.