The effect of tetradecanoylphorbol acetate on calcium-ion mobilization, protein phosphorylation and cytoskeletal assembly induced by thrombin or arachidonate.
The effect of tetradecanoylphorbol acetate on calcium-ion mobilization, protein phosphorylation and cytoskeletal assembly induced by thrombin or arachidonate.
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醋酸十四烷酰佛波醇对凝血酶或花生四烯酸诱导的钙离子动员、蛋白质磷酸化和细胞骨架组装的影响。
DOI：
10.1016/0167-4889(86)90174-6
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Carroll,RC
中科院分区：
文献类型：
--
作者：
Cox,AC;Carroll,RC
十四酰佛波醇乙酸酯（TPA）主要激活血小板中的蛋白激酶C途径，而不是钙离子依赖性途径。这种分裂激活的净效应是，只有伪足细胞骨架组装，而不是快速分泌所需的收缩细胞骨架。在这项研究中，血小板首先用TPA激活，然后用凝血酶或花生四烯酸二次激活，随后的致密体分泌，钙离子动员，蛋白磷酸化和细胞骨架组装与仅用凝血酶或花生四烯酸激活的对照血小板中的这些相同过程相比。随着初次和二次激活之间的时间长度增加，分泌减少;但在TPA激活基本完成的2-3分钟间隔，总放射性标记5-羟色胺分泌的减少很小。此外，几乎正常的胞浆钙离子增加，肌球蛋白轻链磷酸化和收缩性细胞骨架的发展，诱导凝血酶或花生四烯酸后，这一间隔。先前用100 μM乙酰水杨酸处理血小板以阻断环加氧酶依赖性途径，会导致TPA或凝血酶或两者组合诱导的致密体分泌轻微减少，但在其他方面，相对结果与未处理的血小板相当。因此，用TPA短期预先激活凝胶过滤的血小板，即使浓度超过使蛋白激酶C饱和所需的100倍，也不会阻止钙离子依赖性过程通过环加氧酶依赖性或非依赖性途径的正常激活。长期预孵育TPA差异抑制凝血酶和花生四烯酸诱导的分泌反应。
Tetradecanoylphorbol acetate (TPA) activates primarily only the protein kinase C pathway not the calcium ion-dependent pathway in platelets. The net effect of this split activation is that only the pseudopodal cytoskeleton assembles, not the contractile cytoskeleton needed for rapid secretion. In this study, platelets were first activated with TPA, then activated secondarily with either thrombin or arachidonate and the subsequent dense body secretion, calcium-ion mobilization, protein phosphorylation and cytoskeletal assembly compared to these same processes in control platelets activated solely with either thrombin or arachidonate. Secretion was reduced as the length of time between the primary and secondary activation was increased; but at a 2–3 min interval, where the activation by TPA was essentially complete, the reduction in the total radiolabeled serotonin secreted was small. Furthermore, nearly normal cytosolic calcium-ion increases, phosphorylation of myosin light chain and contractile cytoskeletal development were induced by thrombin or arachidonate after this interval. Prior treatment of the platelets with 100 μM acetylsalicylate to block the cyclooxygenase-dependent pathway caused minor reduction in dense-body secretion induced by TPA or thrombin or the combination of both, but otherwise the relative results were comparable to the untreated platelets. Therefore, short-term prior activation of gel-filtered platelets with TPA, even at concentrations in excess of 100-times that required to saturate protein kinase C, does not prevent normal activation of the calcium ion dependent processes through either the cyclooxygenase-dependent or -independent pathway. Longer-term preincubations with TPA differentially inhibit the secretion response induced by thrombin and arachidonate.