Autophosphorylates on all three types of residues. Phosphorylation on Ser-34 and Thr-127 by AKT1 is induced by ionizing radiation or insulin. Phosphorylation plays a critical role in cell proliferation following low dose radiation and prevents cell death following high dose radiation. Phosphorylation at Thr-343 by PKB/AKT2 induces its kinase activity which is required for its stability. The phosphorylation status at Ser-141 influences its subnuclear localization; inhbition of phosphorylation at Ser-141 results in accumulation in the nuclear speckle.