Phosphatidylserine-enriched activated platelet membranes (PS-enriched platelet membranes)

Phosphatidylserine-enriched activated platelet membranes serve as a critical catalytic platform for the blood coagulation cascade. In resting platelets, phosphatidylserine (PS) is actively sequestered in the inner leaflet of the plasma membrane by flippases; however, upon activation by stimuli such as thrombin or collagen, PS is rapidly translocated to the outer leaflet via the action of scramblases (Zwaal & Schroit, 1997). This exposure of negatively charged phospholipids provides a necessary scaffold for the assembly of the tenase and prothrombinase complexes, which accelerate the generation of thrombin by several orders of magnitude compared to reactions in solution (Heemskerk et al., 2013). In pathological states, excessive PS exposure on platelets and platelet-derived microparticles contributes significantly to arterial and venous thrombosis, leading to conditions like myocardial infarction and stroke (Lentz, 2003). Therapeutic strategies targeting these membranes often involve PS-binding proteins, such as Annexin V or its homodimer derivative Diannexin, which mask the PS surface to prevent the binding of coagulation factors IXa, VIIIa, Xa, and Va (Rand et al., 2004). By specifically targeting the activated platelet surface rather than systemic coagulation factors, these agents aim to provide localized antithrombotic effects with a potentially lower risk of systemic bleeding compared to traditional anticoagulants.

Other names

Procoagulant platelet surfacePhosphatidylserine-exposed platelet membraneActivated platelet phospholipid surfaceAnionic phospholipid membraneProcoagulant phospholipid surface

Drugs typically bind to the negatively charged phosphatidylserine headgroups exposed on the outer leaflet of activated platelets, thereby sterically hindering the assembly of the tenase (FIXa/FVIIIa) and prothrombinase (FXa/FVa) complexes and inhibiting thrombin generation (Lentz, 2003; Rand et al., 2004).