The human platelet membrane glycoprotein IIb/IIIa complex: a multi functional adhesion receptor.
The glycoprotein GPIIb/IIIa complex is a major constituent of the platelet membrane; it plays an important role in platelet adhesion and aggregation. The complex is a member of the integrin superfamily. Integrins are related membrane receptors which mediate the adhesive interactions of a variety of cells; they specifically recognize the arginine-glycine-aspartic acid (RGD) sequence present in several adhesive proteins. The GPIIb/IIIa complex of activated platelets can bind fibrinogen, von Willebrand factor, fibronectin, vitronectin and thrombospondin. Platelets are activated by a variety of signals including extracellular matrix molecules and soluble factors; upon platelet activation the complex undergoes a conformational change, thus permitting the macromolecular ligands access to their binding sites. In turn, fibrinogen binding results in a receptor modification and neoantigens exposure; such events may participate in signal transduction. The adhesive proteins compete reciprocally for binding to GPIIb/IIIa, and the complex binds to different domains of them, thus creating multiple interactions with the ligands.
Perutelli
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Laboratorio di Ematologia, Istituto G. Gaslini, Genova, Italy.
Mori
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D000595:Amino Acid Sequence; D016824:Antigens, Human Platelet / Q000502:physiology; D018955:CD36 Antigens; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D010973:Platelet Adhesiveness; D010980:Platelet Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D016024:Receptors, Cytoadhesin / Q000378:metabolism*; D017469:Receptors, Fibronectin / Q000378:metabolism; D019030:Receptors, Vitronectin; D019699:Thrombospondins; D019096:Vitronectin; D014841:von Willebrand Factor / Q000378:metabolism
D016824:Antigens, Human Platelet; D018955:CD36 Antigens; D005353:Fibronectins; D006023:Glycoproteins; D009842:Oligopeptides; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D016024:Receptors, Cytoadhesin; D017469:Receptors, Fibronectin; D019030:Receptors, Vitronectin; D019699:Thrombospondins; D019096:Vitronectin; D014841:von Willebrand Factor; C028254:von Willebrand factor receptor; C047981:arginyl-glycyl-aspartic acid; D005340:Fibrinogen