The PI3K-Akt pathway promotes metabolism, proliferation, cell survival, growth and angiogenesis through phosphorylation of downstream substrates. Key proteins in this pathway are phosphatidylinositol 3-kinase (PI3K) and Akt/Protein Kinase B. Research into this pathway began with the discovery of the oncogene ATK8 in 1977 and the cloning of PKB/Akt in 1991. It was later found that PI3K activates Akt and that phospholipids generated by PI3K are required for Akt activation.