Smith C M, Burris S M, Rao G H, White J G
Department of Pediatrics, University of Minnesota Health Sciences Center, Minneapolis 55455.
Blood. 1992 Dec 1;80(11):2774-80.
This study contrasts the protein composition of the detergent-resistant cytoskeleton of platelets fully spread on glass with the cytoskeletal composition of resting platelets and platelets aggregated in suspension with thrombin. Complete Triton X-100-insoluble cytoskeletons were isolated from spread, resting, and suspension-activated platelets in the presence of protease inhibitors, solubilized in sodium dodecyl sulfate/EDTA and analyzed on reduced, one-dimensional polyacrylamide gels. The protein composition of the cytoskeletons differed both qualitatively and quantitatively. Most notable were more extensive incorporation of total protein, talin, and vinculin into the cytoskeleton of spread platelets than the cytoskeleton of suspension-activated platelets. Varying the concentration and time of exposure to thrombin during suspension activation did not mimic the cytoskeletal changes of surface activation. Scanning electron microscopy, measurement of lipid phosphorus content, and varying the duration of Triton extraction did not show incomplete solubilization or nonspecific trapping of constituents in the spread platelet cytoskeleton. Proteolysis of talin was minimal in suspension-activated platelets and in platelets spread for 50 minutes. The differences in the detergent-resistant cytoskeletons of surface- and suspension-activated platelets indicate significant divergence in the physiologies of platelet spreading on surfaces and platelet activation in suspension.
本研究对比了完全铺展在玻璃上的血小板的抗去污剂细胞骨架的蛋白质组成与静息血小板以及用凝血酶在悬浮液中聚集的血小板的细胞骨架组成。在蛋白酶抑制剂存在的情况下，从铺展、静息和悬浮激活的血小板中分离出完全不溶于Triton X - 100的细胞骨架，将其在十二烷基硫酸钠/乙二胺四乙酸中溶解，并在还原的一维聚丙烯酰胺凝胶上进行分析。细胞骨架的蛋白质组成在定性和定量方面均有所不同。最显著的是，与悬浮激活的血小板的细胞骨架相比，铺展血小板的细胞骨架中总蛋白、踝蛋白和纽蛋白的掺入更为广泛。在悬浮激活过程中改变凝血酶的浓度和暴露时间并不能模拟表面激活的细胞骨架变化。扫描电子显微镜、脂质磷含量的测量以及改变Triton提取的持续时间均未显示铺展血小板细胞骨架中存在不完全溶解或成分的非特异性截留。在悬浮激活的血小板和铺展50分钟的血小板中，踝蛋白的蛋白水解作用最小。表面激活和悬浮激活的血小板的抗去污剂细胞骨架的差异表明，血小板在表面铺展和在悬浮液中激活的生理过程存在显著差异。
