SnapShot: p53 Posttranslational Modifications

P ho sp ho ry la ti o n N-Terminal: S6, S9, S15, T18, S20 ATM, DNAPK, • CK1 ERKs, ATR, p38 • kinase, mTOR, Chk1/Chk2, JNK, MAPKAP2, Hipk4 Activated by DNA damage, UV light, ionizing radiation, replicative senes• cence, or phosphatidylcholines. N-terminal phosphorylation causes p53 stabilization by inhibiting the p53• MDM2 interaction. Knockin mice carrying separate analogs to human Ser18/ • Ser23 mutation are phenotypically normal. Thymocytes from Ser18 mutant mice are susceptible to ionizing radiation-induced apoptosis, whereas S23 mutation in ES cells and MEFs is dispensable for p53 stabilization and activation. Ser18/Ser23 double mutant knockin mice display reduced apoptosis in thymocytes and develop some malignancies. Very rare mutations reported in human tumors. •