PI3K

PI3K (Phosphoinositide 3-kinase), via phosphorylation of the inositol lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), forms the second messenger molecule phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) which recruits and activates pleckstrin homology domain containing proteins, leading to downstream signalling events crucial for proliferation, survival and migration. Class I PI3K enzymes consist of four distinct catalytic isoforms, PI3Kα, PI3Kβ, PI3Kδ and PI3Kγ. There are three major classes of PI3K enzymes, being class IA widely associated to cancer. Class IA PI3K are heterodimeric lipid kinases composed of a catalytic subunit (p110α, p110β, or p110δ; encoded by PIK3CA, PIK3CB, and PIK3CD genes, respectively) and a regulatory subunit (p85). The PI3K pathway plays an important role in many biological processes, including cell cycle progression, cell growth, survival, actin rearrangement and migration, and intracellular vesicular transport.