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Vitronectin (S protein) is associated with platelets
Author(s) -
Parker C. J.,
Stone O. L.,
White V. F.,
Bernshaw N. J.
Publication year - 1989
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1989.tb04262.x
Subject(s) - vitronectin , platelet , fibronectin , chemistry , microbiology and biotechnology , thrombin , glycoprotein , integrin , platelet membrane glycoprotein , biochemistry , biology , cell , immunology
Summary Vitronectin is a plasma glycoprotein that has regulatory activity in the complement and the coagulation systems, in cell‐cell and cell‐substrate interactions, and in monocyte/macrophage function. Because of its potential to participate in several of the processes of inflammation and repair, the association of vitronectin with platelets was investigated. Immunochemical studies demonstrated that the majority of the platelet associated vitronectin was intracellular, while a relatively modest amount was localized to the ectoplasmic portion of the plasma membrane. Analysis by Western blot showed that the electrophoretic mobility of platelet associated vitronectin was indistinguishable from that of vitronectin isolated from plasma. In response to thrombin, approximately 1 μg of vitronectin was released into the supernate of 10 9 platelets, while somewhat less than one‐half of the total platelet vitronectin remained cell associated. The binding of vitronectin to platelets was investigated by comparing the capacity of unlabelled vitronectin and fibronectin to inhibit binding of radiolabelled fibronectin to thrombin stimulated platelets. On a weight basis, inhibition by the two proteins was equivalent, suggesting that vitronectin competes with fibronectin for binding to platelet glycoprotein IIb/IIIa. These results demonstrate that vitronectin is a platelet specific protein which, because of its multifunctional properties, may participate in physiological and pathophysiological events associated with thrombosis and haemostasis.