Keeping p53 in check: essential and synergistic functions of Mdm2 and Mdm4.

The article focuses on keeping p53 in check under functions of Mdm2 and Mdm4 proteins. In the absence of stress signals, the p53 protein is kept in check to allow normal cell proliferation and maintenance of cell viability. In this process, the critical importance are the two structurally related proteins, the Mdm2 and Mdm4 proteins. Germline inactivation of either mdm2 and mdm4 leads to embryonic lethal phenotypes that are completely overcome by noncomitant inactivation of the p53 gene.