Akt, also known as protein kinase B (PKB), a serine/ threonine kinase, is a critical enzyme in several signal transduction pathways involved in cell proliferation, apoptosis, angiogenesis, and diabetes. Akt is activated following its phosphorylation at two regulatory residues. Phosphorylation of threonine on the kinase domain, catalyzed by PDK1, is essential for Akt activation. Akt activity is augmented approximately 10-fold by phosphorylation at the serine on the hydrophobic motif by PDK2. Phosphorylation of Thr308 and Ser473 activates Akt α. Phosphorylation at Thr309 and Ser474 on Akt β1 and β2, and on Thr305 on Akt γ result in their activation. Akt promotes cell survival by inhibiting apoptosis by phosphorylating and inactivating several targets, including Bad, forkhead transcription factors, c-Raf and caspase-9. The activation of Akt is negatively regulated by PTEN, a PIP3 specific phosphatase, and SHIP, a SH2-domain containing inositol 5-phosphatase.