CD61, also called integrin beta-3, belongs to the integrin protein family that participates in cell adhesion and cell-surface mediated signalling by forming heterodimers of alpha and beta integrin chains. Integrin alpha-V/beta-3 is a receptor for cytoactin, fibronectin, laminin, matrix metalloproteinase-2, osteopontin, osteomodulin, prothrombin, thrombospondin, vitronectin and von Willebrand factor. Integrin alpha-IIb/beta-3 is a receptor for fibronectin, fibrinogen, plasminogen, prothrombin, thrombospondin and vitronectin. These two integrins recognize the sequence RGD in a wide array of ligands. Integrin IIb/IIIa recognizes the sequence HHLGGGAKQAGDV in fibrinogen gamma chain. Following activation, integrin alpha-IIb/beta-3 supports platelet/platelet interaction through binding of soluble fibrinogen, leading to rapid platelet aggregation which physically plugs ruptured endothelial surface. Defects in CD61 are a cause of Glanzmann thrombasthenia, a blot clot disorder.