Altmüller A, Presek P
Rudolf-Buchheim-Institut für Pharmakologie, Justus-Liebig-Universität, Giessen, Germany.
Biochim Biophys Acta. 1995 Feb 16;1265(1):61-6. doi: 10.1016/0167-4889(94)00194-j.
Upon activation platelets show elevated protein tyrosine phosphorylation, and translocation of the protein tyrosine kinase pp60c-src from the plasma membrane to the cytoskeleton occurs. We therefore investigated whether tyrosine phosphorylation also increases in the cytoskeletal compartment. Here we show that almost identical patterns of phosphotyrosine-containing proteins are detectable in the cytoskeleton after platelet stimulation with compounds that directly (phorbol 12-myristate, 13-acetate) or indirectly (thrombin, vasopressin, collagen, ADP) activate protein kinase C. The apparent molecular masses of the proteins phosphorylated at tyrosine residues are 145, 130, 100, 85, 80, 60, 56, 54 and 38 kDa. Elevation of cyclic AMP by prostaglandin E1 had no effect. Concentrations of thrombin as low as 0.01 units per ml are able to cause tyrosine phosphorylation of multiple proteins. The time course of protein tyrosine phosphorylation for thrombin- and vasopressin-stimulated platelets revealed a rapid increase in the cytoskeleton within 5 to 20 s following activation consistent with a role in early events of platelet function.
血小板激活后，蛋白酪氨酸磷酸化水平升高，并且蛋白酪氨酸激酶pp60c-src从质膜转位至细胞骨架。因此，我们研究了细胞骨架区室中的酪氨酸磷酸化是否也会增加。在此我们表明，在用直接（佛波醇12-肉豆蔻酸酯13-乙酸酯）或间接（凝血酶、血管加压素、胶原蛋白、ADP）激活蛋白激酶C的化合物刺激血小板后，在细胞骨架中可检测到几乎相同的含磷酸酪氨酸蛋白模式。在酪氨酸残基处被磷酸化的蛋白的表观分子量分别为145、130、100、85、80、60、56、54和38 kDa。前列腺素E1使环磷酸腺苷升高没有作用。低至每毫升0.01单位的凝血酶浓度就能引起多种蛋白的酪氨酸磷酸化。凝血酶和血管加压素刺激的血小板的蛋白酪氨酸磷酸化的时间进程显示，激活后5至20秒内细胞骨架中的磷酸化迅速增加，这与在血小板功能早期事件中的作用一致。
