Phosphatidylinositol Trisphosphate (PIP3)

Phosphatidylinositol (3,4,5)-trisphosphate is the product of the class I phosphoinositide 3-kinases (PI 3-kinases) phosphorylation on phosphatidylinositol (4,5)-bisphosphate (PIP2). PIP3 functions to activate downstream signaling components, most notably the protein kinase AKT, which activates downstream anabolic signaling pathways required for cell growth and survival.PtdIns(3,4,5)P3 is dephophosphorylated by the phosphatase, PTEN on the 3 position, generating PI(4,5)P2, and by SHIPs (SH2-containing inositol phosphatase) on the 5""" position of the inositol ring, producing PI(3,4)P2.The PH domain allows binding between PtdIns(3,4,5)P3 and G-protein coupled receptor kinases (GRKs). This enhances the binding of the GRK to the plasma membrane.