AKT phosphorylates MDM2 on two serine residues, at positions 166 and 188 (Mayo and Donner 2001, Feng et al. 2004, Milne et al. 2004). AKT-mediated phosphorylation of the E3 ubiquitin-protein ligase MDM2 promotes nuclear localization and interferes with the interaction between MDM2 and p14-ARF, thereby decreasing p53 stability. This leads to a decreased expression of p53 target genes, such as BAX, that promote apoptosis (Zhou et al. 2001, Mayo and Donner 2001).