Protein Mdm4 (MDM4)

Protein Mdm4, commonly known as MDMX, is a critical negative regulator of the p53 tumor suppressor protein. Structurally similar to MDM2, MDM4 functions by binding to the N-terminal transactivation domain of p53, thereby inhibiting its transcriptional activity and promoting its degradation through the formation of MDM2-MDM4 heterocomplexes. Unlike MDM2, MDM4 lacks strong intrinsic E3 ubiquitin ligase activity but is essential for maintaining low p53 levels during normal embryonic development and in resting cells. MDM4 is frequently overexpressed or amplified in various human cancers, particularly those retaining wild-type p53, such as melanoma and breast cancer, making it a high-priority therapeutic target. Pharmacological strategies often focus on dual MDM2/MDM4 inhibitors or stapled peptides designed to disrupt the p53-MDM4 interface, effectively reactivating the p53 pathway to induce cell cycle arrest and apoptosis in malignant cells.

Other names

Mouse double minute 4 homologMDMXDouble minute 4 proteinHDMXp53-binding protein Mdm4

Inhibition of MDM4-p53 interaction to restore p53-mediated tumor suppression and apoptosis