Newman P J, Kawai Y, Montgomery R R, Kunicki T J
J Cell Biol. 1986 Jul;103(1):81-6. doi: 10.1083/jcb.103.1.81.
Human platelets participate in a number of adhesive interactions, including binding to exposed subendothelium after vascular injury, and platelet-platelet cohesion to form large aggregates. Platelet membrane glycoproteins (GP) IIb and IIIa constitute a receptor for fibrinogen that, together with fibrinogen and calcium, is largely responsible for mediating the formation of the primary hemostatic plug. Using highly specific polyclonal and monoclonal antibodies as probes, we could detect the presence of both of these glycoproteins in cultured human umbilical vein endothelial cells. Western-blot analysis showed that the endothelial cell analogues were similar in size to their platelet counterparts, and were present in cells that had been in culture for over 2 mo. Metabolic labeling of endothelium with [35S]methionine demonstrated that both GPIIb and GPIIIa were actively synthesized in culture. Using the technique of crossed immunoelectrophoresis, evidence was obtained that the endothelial cell forms of GPIIb and GPIIIa may exist complexed to one another after solubilization in Triton X-100. The presence of GPIIb-IIIa analogues in cultured endothelial cells may provide an opportunity to examine the structure, function, and synthesis of these two membrane glycoproteins, as well as provide a source of genetic material with which to begin detailed molecular genetic studies.
人类血小板参与多种黏附相互作用，包括在血管损伤后与暴露的内皮下层结合，以及血小板与血小板之间的黏附以形成大的聚集体。血小板膜糖蛋白（GP）IIb和IIIa构成纤维蛋白原的受体，该受体与纤维蛋白原和钙一起，在很大程度上负责介导初级止血栓的形成。使用高度特异性的多克隆和单克隆抗体作为探针，我们能够在培养的人脐静脉内皮细胞中检测到这两种糖蛋白的存在。蛋白质免疫印迹分析表明，内皮细胞类似物的大小与其血小板对应物相似，并且存在于培养超过2个月的细胞中。用[35S]甲硫氨酸对内皮进行代谢标记表明，GPIIb和GPIIIa在培养物中均被活跃地合成。使用交叉免疫电泳技术，获得的证据表明，在Triton X-100中溶解后，内皮细胞形式的GPIIb和GPIIIa可能彼此复合存在。培养的内皮细胞中存在GPIIb-IIIa类似物，这可能为研究这两种膜糖蛋白的结构、功能和合成提供机会，也为开始详细的分子遗传学研究提供遗传物质来源。
