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Overview of Platelet Adhesion Proteins and Ligands
Platelets adhere to the vascular endothelium at sites of endothelial injury where extracellular matrix (ECM) components in the sub-endothelial space are exposed to the circulation. GP family glycoproteins mediate rapid tethering to ECM molecules at these sites. Integrin heterodimers become activated and then provide robust platelet adhesion. Adhesion is an early phase of platelet activation and limits bleeding by promoting platelet aggregation and clot formation (thrombosis). Circulating molecules, such as vWF-A2 and Thrombospondin also contribute to platelet aggregate formation. In addition, platelets can form circulating aggregates with monocytes and leukocytes to enhance systemic inflammatory responses.