Integrin subunit beta 3 (ITGB3) (ITGB3)

Integrin subunit beta 3 (ITGB3), also known as CD61 or glycoprotein IIIa (GPIIIa), is a transmembrane protein that functions as a subunit for two major integrin receptors: the platelet-specific alpha-IIb/beta-3 (GPIIb/IIIa) and the more widely expressed alpha-v/beta-3 (UniProt P05106). On the surface of platelets, the GPIIb/IIIa complex is essential for blood clotting, as it undergoes a conformational change to bind fibrinogen and mediate platelet aggregation (NCBI Gene 3690). The HPA-1a isoform is a specific polymorphic variant of ITGB3, characterized by a leucine at amino acid position 33, and is the most prevalent platelet antigen in Caucasian populations (PubMed 29433111). This isoform is clinically significant as the primary target in Fetal and Neonatal Alloimmune Thrombocytopenia (FNAIT), a condition where an HPA-1a-negative mother produces antibodies against the HPA-1a-positive platelets of her fetus (StatPearls). While general Integrin beta-3 inhibitors like abciximab are used as anti-thrombotics, novel therapies such as RLYB212 specifically target the HPA-1a isoform to prevent maternal alloimmunization (Rallybio). Understanding this target is crucial for managing both thrombotic disorders and pregnancy-related alloimmune complications.

Other names

CD61Glycoprotein IIIaGPIIIaPlatelet antigen 1HPA-1aIntegrin beta-3

Inhibition of fibrinogen binding to the GPIIb/IIIa complex to prevent platelet aggregation; antibody-mediated clearance or masking of the HPA-1a epitope to prevent maternal alloimmunization in FNAIT.