Phosphoinositide 3-kinase class I isoforms (PI3K)

Phosphoinositide 3-kinase class I isoforms (PI3K) are a family of lipid kinases that play central roles in regulating cell growth, proliferation, survival, metabolism, and immune function. They are heterodimeric enzymes composed of a catalytic subunit (p110 isoforms) and a regulatory subunit. Class I PI3Ks are further divided into two subclasses: IA (p110α, p110β, p110δ) and IB (p110γ). Activation is triggered by cell-surface receptors including receptor tyrosine kinases (RTKs) and G protein-coupled receptors (GPCRs), leading to the conversion of phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P₂] to phosphatidylinositol (3,4,5)-trisphosphate [PIP₃], which activates downstream signaling pathways such as AKT/mTOR. They are frequently mutated or dysregulated in human cancers, making them a major drug target. Inhibitors targeting specific isoforms have been developed primarily for oncology indications.

Other names

PI3K class IPhosphatidylinositol 3-kinase class I

Inhibition of PI3K isoforms