The activation of the AKT pathway begins with the binding of growth factors to RTKs, which leads to the activation of phosphoinositide 3-kinase (PI3K). Activated PI3K converts PIP2 (phosphatidylinositol 4,5-bisphosphate) into PIP3 (phosphatidylinositol 3,4,5-trisphosphate). PIP3 serves as a docking site for AKT and its upstream activator PDK1 (phosphoinositide-dependent kinase-1). PDK1 phosphorylates and activates AKT, which then goes on to phosphorylate various downstream effectors.
