Phosphatidylinositol-3-kinase (PI3K)

Phosphatidylinositol-3-kinases (PI3Ks) are a family of intracellular enzymes that play a central role in cellular signaling. They are involved in regulating key cellular processes such as cell growth, proliferation, differentiation, motility, survival, and intracellular trafficking. Dysregulation of PI3K activity is implicated in various diseases, most notably cancer. PI3Ks phosphorylate the 3' hydroxyl group of the inositol ring of phosphatidylinositol lipids. The main product is phosphatidylinositol-3,4,5-trisphosphate (PIP₃), which acts as a second messenger to recruit and activate downstream signaling proteins containing pleckstrin homology (PH) domains. The tumor suppressor PTEN antagonizes PI3K by dephosphorylating PIP₃ back to PIP₂; loss or mutation of PTEN leads to hyperactivation of this pathway—a common event in cancers.

Other names

Phosphoinositide 3-KinasePI3 Kinase

Inhibition of PI3K activity, blocking downstream signaling pathways such as AKT and mTOR.