Glycoprotein complexes, platelet adhesion

The von Willebrand factor (vWf) is a heterogeneous multimeric plasma glycoprotein produced by megakaryocytes and endothelial cells which is found in platelets, plasma and the subendothelium. Subendothelial vWf facilitates platelet adhesion, especially under high shear stress, by binding to glycoprotein GPIb-V-IX, a complex of four leucine-rich repeat proteins on platelets. 

Kunicki TJ, Nugent DF, Staatz S, Ordiekowski RP, Wayner EA, Carter WG The human fibroblast class Q extracellular matrix receptor mediates platelet adhesion to collagen and is identical to the platelet glycoprotein la-IIa complex. J Biol Chem 263 4516-4519,1988... 

The specific platelet surface receptors that support these initial adhesive interactions are determined by the local fluid dynamic conditions of the vasculature and the extracellular matrix constituents exposed at the sites of vascular injury. Konstantopolous et al. (1998) and Alveriadou et al. (1993) demonstrated that under high shear conditions, the adhesion of platelets to exposed subendothelial surfaces of atherosclerotic or injured vessels presenting collagen and von Willebrand factor (vWF) is primarily mediated by the platelet glycoprotein (GP)Ib/IX/V complex. This primary adhesion to the matrix activates platelets, leading ultimately to platelet aggregation mediated... 

Hemostasis is a complex sequence of interrelated events involving toe vessel wall, platelets, and the coagulation system. Following injury to the blood vessel, platelets adhere to exposed subendothelium by a process (adhesion) which involves the interaction of a plasma protein, von Willebiand factor (vWF), and a specific protein on the platelet sur ce, glycoprotein Ib (GPIb) (Fig 1). Adhesion is followed by recruitment of additional platelets which form clumps. 

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