Activated platelet surface phospholipids (PS)

Activated platelet surface phospholipids, specifically phosphatidylserine (PS), serve as a critical catalytic platform for the assembly of blood coagulation factor complexes. In resting platelets, PS is sequestered in the inner leaflet of the plasma membrane by flippases; however, upon activation by stimuli such as thrombin or collagen, a calcium-dependent scramblase translocates PS to the outer surface (Bevers & Williamson, 2016, PMID: 26803364). This exposed anionic surface provides the necessary environment for the binding of vitamin K-dependent clotting factors through their gamma-carboxyglutamic acid (GLA) domains, facilitating the exponential generation of thrombin (Lentz, 2003, PMID: 12686525). Pathologically, the overexposure of these phospholipids is a hallmark of arterial and venous thrombosis and is also observed on tumor-associated microparticles, contributing to cancer-associated hypercoagulability (Schroit & Zwaal, 1991, PMID: 1831044). Therapeutic strategies targeting these phospholipids include imaging agents like Annexin V for detecting active clots and monoclonal antibodies like Bavituximab, which are designed to block the procoagulant or immunosuppressive effects of exposed PS in the tumor microenvironment (Heemskerk et al., 2013, PMID: 23413240).

Other names

PhosphatidylserineProcoagulant phospholipidsAnionic phospholipidsPlatelet-derived microparticlesProcoagulant platelet surface

Binding to negatively charged phospholipids (primarily phosphatidylserine) exposed on the outer leaflet of activated platelets to inhibit the assembly of tenase and prothrombinase complexes or to serve as a molecular target for thrombus imaging.