Thrombin and activators of protein kinase C modulate secretory responses of permeabilised human platelets induced by Ca2+.
Thrombin and activators of protein kinase C modulate secretory responses of permeabilised human platelets induced by Ca2+.
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凝血酶和蛋白激酶 C 激活剂调节 Ca2 诱导的透化人血小板的分泌反应。
DOI：
10.1111/j.1432-1033.1984.tb08391.x
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
M. Scrutton
中科院分区：
文献类型：
--
作者：
D. Knight;V. Niggli;M. Scrutton
添加凝血酶可增强人血小板中 Ca2+ 诱导的 [14C] 血清素和 β-N-乙酰氨基葡萄糖苷酶的分泌，而人血小板因暴露于强电场而变得可渗透。凝血酶对 β-N-乙酰氨基葡萄糖苷酶分泌的增强是由于最大反应程度的增加，而 Ca2+ 的中位有效浓度 EC50 没有显着变化。相反，凝血酶将Ca2+诱导的[14C]血清素分泌的剂量/反应曲线向左移动，并且对该反应的最大程度几乎没有影响，即使通过使用非饱和浓度的MgATP2-来降低该程度。在存在或不存在凝血酶的情况下，反应程度与 [MgATP2-] 之间的关系与 [14C] 血清素和 β-N-乙酰氨基葡萄糖苷酶的分泌相似。还观察到类似的核苷酸特异性。蛋白激酶 C 激活剂先前已被证明可以定量模拟凝血酶对 Ca2+ 诱导的 [14C] 血清素分泌的影响 [D. E. Knight 和 M. C. Scrutton (1984) Nature (伦敦) 309, 66-68]。此类激活剂对 Ca2+ 诱导的 β-N-乙酰氨基葡萄糖苷酶分泌特性具有与凝血酶相同的定性效果，但效果较差。观察到[14C]血清素和β-N-乙酰氨基葡萄糖苷酶分泌增强的凝血酶EC50与在可比条件下完整血小板获得的EC50范围相同[D. E. Knight、T. J. Hallam 和 M. C. Scrutton (1982) Nature (Lond.) 296, 256-257]。在这些系统中观察到的蛋白激酶 C 激活剂的 EC50 和响应特异性与之前报道的纯化酶一致。在[γ-32P] ATP存在下向透化血小板中添加1-10μM Ca2+导致32P掺入分子量为20kDA、45kDA和66kDA的多肽中的显着增强。当凝血酶与 10 microM Ca2+ 一起添加时，在该系统中没有额外的多肽被磷酸化，但观察到 45-kDa 多肽的磷酸化程度有所增加。添加 1-油基-2-乙酰甘油 + 1 - 2 microM Ca2+ 导致 45-kDa 多肽的磷酸化增强，20-kDa 多肽的磷酸化程度较小。在存在和不存在 1-油基-2-乙酰甘油的情况下，45-kDa 多肽的 Ca2+ 依赖性磷酸化的剂量/反应曲线与在这些条件下观察到的 Ca2+ 依赖性 [14C] 血清素分泌的剂量/反应曲线相似。（摘要截断为 400 字）
Addition of thrombin enhances secretion of both [14C]serotonin and beta-N-acetylglucosaminidase induced by Ca2+ in human platelets rendered permeable by exposure to intense electric fields. Enhancement of beta-N-acetylglucosaminidase secretion by thrombin results from an increase in the maximal extent of the response with no significant change in the median effective concentration EC50 for Ca2+. In contrast, thrombin shifts the dose/response curve for Ca2+-induced [14C]serotonin secretion to the left and has little effect on the maximal extent of this response even when this extent is reduced by use of a non-saturating concentration of MgATP2-. The relationship between extent of response and [MgATP2-] is similar for secretion of [14C]serotonin and of beta-N-acetylglucosaminidase in the presence or absence of thrombin. Similar nucleotide specificities are also observed. Activators of protein kinase C have previously been shown to mimic quantitatively the effect of thrombin on [14C]serotonin secretion induced by Ca2+ [D. E. Knight & M. C. Scrutton (1984) Nature (Lond.) 309, 66-68]. Such activators have the same qualitative effect as thrombin on the properties of beta-N-acetylglucosaminidase secretion induced by Ca2+ but are less effective. The EC50 for thrombin observed for enhancement of [14C]serotonin and beta-N-acetylglucosaminidase secretion is in the same range as that obtained for intact platelets under comparable conditions [D. E. Knight, T. J. Hallam & M. C. Scrutton (1982) Nature (Lond.) 296, 256-257]. The EC50, and the specificity of response, observed for activators of protein kinase C in these systems are consistent with those reported previously for the purified enzyme. Addition of 1-10 microM Ca2+ to permeabilised platelets in the presence of [gamma-32P] ATP causes marked enhancement of 32P incorporation into polypeptides of molecular mass 20 kDA, 45 kDA and 66 kDA. No additional polypeptides become phosphorylated in this system when thrombin is added together with 10 microM Ca2+, but some increase is observed in the extent of phosphorylation of the 45-kDa polypeptide. Addition of 1-oleyl-2-acetylglycerol + 1 - 2 microM Ca2+ causes enhanced phosphorylation of the 45-kDa polypeptide and to a lesser extent of the 20-kDa polypeptide. The dose/response curves for Ca2+-dependent phosphorylation of the 45-kDa polypeptide in the presence and absence of 1-oleyl-2-acetylglycerol are similar to those observed for Ca2+-dependent [14C]serotonin secretion under these conditions.(ABSTRACT TRUNCATED AT 400 WORDS)
凝血酶诱导的血小板反应对受体占据的要求不同。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Holmsen,H;Dangelmaier,CA;Holmsen,HK
通讯作者：
Holmsen,HK