Phosphatidylinositol 3-kinase alpha and delta (PI3Kα and PI3Kδ)

Phosphatidylinositol 3-kinase alpha and delta are catalytic subunits (p110α and p110δ) of Class IA PI3K enzymes, operating as lipid kinases in heterodimeric complexes and regulated by distinct adapter proteins (p85α for PI3Kα, p85 for PI3Kδ). PI3Kα predominantly drives signaling downstream of receptor tyrosine kinases and is frequently mutated in solid tumors, where these mutations lead to aberrant cell growth, proliferation, and metabolic reprogramming. PI3Kδ is chiefly expressed in leukocytes and orchestrates immune signaling; its dysregulation is associated with hematological malignancies and immunodeficiencies. Both are intensely studied as drug targets, with several isoform-selective inhibitors in clinical use and ongoing development aimed at minimizing toxicity and enhancing therapeutic index.

Other names

PIK3CAp110αPIK3CDp110δ

ATP-competitive inhibition of kinase activity. Isoform-selective blockade of downstream signaling pathways (e.g., PI3K/AKT/mTOR)