Akt3 (v-akt murine thymoma viral oncogene homolog 3) is a 479-amino acid protein (~53kDa), belongs to the AKT serine/threonine protein kinase family, which also includes Akt1 and Akt2. 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. Akt3 is not required for the maintenance of normal carbohydrate metabolism but is essential for the attainment of normal organ size. Identifying Akt3 as a selective target in melanoma cells also provides new therapeutic opportunities for patients in the advanced stages of this disease.