Exposure of binding sites for vitronectin on platelets following stimulation.
Exposure of binding sites for vitronectin on platelets following stimulation.
复制标题
刺激后血小板上玻连蛋白结合位点的暴露。
DOI：
10.1016/s0021-9258(18)69172-0
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
K. Kelly
中科院分区：
文献类型：
--
作者：
P. Thiagarajan;K. Kelly
玻连蛋白是一种糖蛋白，在许多细胞培养系统中介导细胞粘附和铺展。含有血小板糖蛋白IIb-IIIa复合物的脂质体已显示通过Arg-Gly-Asp细胞附着机制结合玻连蛋白包被的表面。我们检查了完整、静息血小板表面和刺激后玻连蛋白结合位点的表达。125 I标记的玻连蛋白以可饱和的方式特异性地与用生理浓度的凝血酶处理的血小板结合。结合在100 nM浓度下达到饱和，并且在饱和时，每个血小板检测到约5000个特异性结合位点。结合是二价阳离子依赖性的，完全饱和后仅部分可逆。含有Arg-Gly-Asp序列的合成六肽抑制玻连蛋白与血小板的结合。抗血小板糖蛋白IIb-IIIa复合物的单克隆抗体也抑制玻连蛋白与刺激的血小板的结合。这些数据表明，血小板具有诱导型二价阳离子依赖性受体的玻连蛋白和糖蛋白IIb-IIIa复合物参与的玻连蛋白受体的表达。
Vitronectin is a glycoprotein that mediates cell adhesion and spreading in a number of cell culture systems. Liposomes containing platelet glycoproteins IIb-IIIa complex have been shown to bind vitronectin-coated surfaces through an Arg-Gly-Asp cell attachment mechanism. We examined the expression of the binding sites for vitronectin on the surface of intact, resting platelets and following stimulation. 125I-Labeled vitronectin bound specifically in a saturable manner to platelets treated with physiological concentrations of thrombin. The binding reached saturation at 100 nM concentration, and, at saturation, approximately 5000 specific binding sites were detected per platelet. The binding was divalent cation-dependent and only partially reversible after complete saturation. A synthetic hexapeptide containing the Arg-Gly-Asp sequence inhibited vitronectin binding to platelets. A monoclonal antibody against platelet glycoprotein IIb-IIIa complex also inhibited the binding of vitronectin to stimulated platelets. These data suggest that platelets possess an inducible divalent cation-dependent receptor for vitronectin and that the glycoprotein IIb-IIIa complex is involved in the expression of the vitronectin receptor.