Phosphatidylserine–beta-2-glycoprotein I complex (Phosphatidylserine–β2GPI complex)

The **phosphatidylserine–beta-2-glycoprotein I complex** is a molecular complex formed by the binding of beta-2-glycoprotein I (β2GPI), a plasma glycoprotein involved in hemostasis and immune regulation, to the anionic phospholipid phosphatidylserine on cell membranes. This complex is the principal antigenic target in the autoimmune condition antiphospholipid syndrome (APS), in which autoantibodies recognize the PS–β2GPI complex, leading to abnormal coagulation, thrombosis, and pregnancy morbidity. β2GPI can modulate the activity of platelets, endothelial cells, and components of the complement system depending on its conformation and binding state. The presence of antibodies against this complex is used diagnostically in APS and represents both a major biomarker and pathogenic mechanism of the disease. While not a classic drug target (like a receptor or enzyme), the PS–β2GPI complex is the centerpiece of therapeutic and diagnostic interest in APS and related autoimmune disorders.

Other names

Phosphatidylserine–β2GPI complexPS–β2GPI complex

Autoantibodies (especially antiphospholipid antibodies) bind the PS–β2GPI complex, triggering immune-mediated pathogenic effects such as platelet activation, endothelial activation, complement activation, and thrombosis These immune complexes play a central role in the pathology of antiphospholipid syndrome