Mouse double minute X homolog (MDMX)

Mouse double minute X homolog (MDMX), also known as MDM4, is a protein closely related to mouse double minute 2 homolog (MDM2). Both are key negative regulators of the tumor suppressor p53 and play critical roles in cell cycle regulation, DNA damage response, and tumorigenesis. MDMX primarily acts by binding to p53 and inhibiting its transcriptional activity. Unlike MDM2, MDMX has weak intrinsic E3 ubiquitin ligase activity, but it enhances p53 degradation when forming heterodimers with MDM2. Overexpression or amplification of MDMX is linked to various cancers due to its role in suppressing p53 function.

Other names

MDM4Mouse double minute 4 homologHDMXHDM4

Inhibition of p53 transcriptional activity by binding to its transactivation domain; Enhancement of p53 ubiquitination and degradation when complexed with MDM2.