||Akt is a serine, threonine protein kinase critical in cellular metabolism, glucose uptake, protein synthesis, cell proliferation, growth, apoptosis, survival, angiogenesis, migration and invasion. It acts downstream of the phosphatidylinositol 3 kinase (PI3K) and it mediates the effects of several growth factors such as platelet-derived growth factor, epidermal growth factor and insulin growth factor. It is activated by phosphorylation on Ser-473, Thr-308 and Tyr-474 and when active it phosphorylates transcription factors (FOXO1), kinases (GSK-3, Raf-1, ASK, Chk1) and other signaling proteins (Bad, MDM2). There are three Akt isoforms (Akt1, Akt2 and Akt3) which share 80% sequence identity also known as PKBα, PKBβ and PKBγ. Akt has been shown to have a role in metabolism, apoptosis and proliferation and therefore it has been proposed to be the candidate "Warburg Kinase".