The accumulation of thrombin at sites of vascular injury provides one of the chief means for
recruiting platelets into a growing hemostatic plug. Studies completed over the past 10 years
show that platelet responses to thrombin are mediated by a subset of G protein-coupled
receptors known as protease-activated receptors. These receptors are activated on
cleavage by thrombin, initiating the intracellular signaling events needed to transform
mobile, nonadhesive platelets into cells that can participate in the growth of an immobile …