Platelet integrin alpha-IIb beta-3 (αIIbβ3 (also known as GPIIb/IIIa))

Platelet integrin alpha-IIb beta-3 (αIIbβ3) is a heterodimeric transmembrane receptor found abundantly on platelets. It is required for the final common pathway of platelet aggregation by binding to fibrinogen and other RGD-motif ligands, thereby mediating cell-cell and cell-matrix adhesion crucial for thrombus formation. The receptor exists in a dynamic equilibrium between an inactive bent conformation and an activated extended state, regulated by intracellular and extracellular signals (inside-out and outside-in signaling). Binding of antagonists such as eptifibatide and tirofiban inhibits ligand binding and platelet aggregation, providing powerful clinical tools for prevention and management of acute coronary syndromes and other thrombotic events, but with notable risks including bleeding and drug-induced immune reactions. The receptor is also functionally implicated in inherited and acquired platelet disorders such as Glanzmann's thrombasthenia and ITP

Other names

Glycoprotein IIb/IIIaGPIIb/IIIaCD41/CD61ITGA2B/ITGB3Integrin alpha-IIb/beta-3

Competitive inhibition of ligand binding (e.g., fibrinogen/platelet interaction), allosteric modulation (conformational changes block activation), direct binding to RGD site to prevent aggregation