AKT3  RAC-gamma serine/threonine-protein kinase is an enzyme that in humans is encoded by the "AKT3" gene. The protein encoded by this gene is a member of the AKT subfamily of serine/threonine protein kinases. AKT kinases are known to be regulators of cell signaling in response to insulin and growth factors. They are involved in a wide variety of biological processes including cell proliferation, differentiation, apoptosis, tumorigenesis, as well as glycogen synthesis and glucose uptake. This kinase has been shown to be stimulated by platelet-derived growth factor (PDGF), insulin, and insulin-like growth factor 1 (IGF1). Alternatively splice transcript variants encoding distinct isoforms have been described. Mice lacking Akt3 have a normal glucose metabolism (no diabetes), have approximately normal body weight, but have a 25% reduction in brain mass. Incidentally, Akt3 is highly expressed in the brain. AKT3 has been shown to interact with Protein kinase Mζ.