A role for 5,6-epoxyeicosatrienoic acid in calcium entry by de novo conformational coupling in human platelets
A role for 5,6-epoxyeicosatrienoic acid in calcium entry by de novo conformational coupling in human platelets
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DOI：
10.1113/jphysiol.2005.100800
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发表时间：
2006-01-15
影响因子：
5.5
通讯作者：
Rosado, JA
中科院分区：
文献类型：
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作者：
Ben-Amor, N;Redondo, PC;Rosado, JA
非兴奋细胞中Ca 2+进入的主要途径在细胞内Ca 2+储存耗尽后被激活。已提出质膜（PM）和Ca 2+库中的元素之间的从头构象耦合是激活包括血小板在内的几种细胞类型中的这种容量性Ca 2+进入（CCE）的最可能机制。在这里，我们报告，细胞色素P450代谢产物，5，6-EET，可能是一个组成部分的从头构象耦合在人类血小板。在这些细胞中，5，6-EET诱导二价阳离子进入，而对Ca 2+储存耗尽没有任何可检测的影响。5，6-EET诱导的Ca 2+内流对CCE阻断剂2-APB、镧、SKF-96365和镍敏感，并通过与抗hTRPC 1抗体孵育而受损。细胞色素P450抑制剂17-ODYA对CCE没有影响，细胞色素P450抑制剂17-ODYA通过使用2，5-二-（叔丁基）-1，4-氢醌消耗酸性储存介导的CCE，损害了低浓度毒胡萝卜素刺激的Ca 2+进入，毒胡萝卜素选择性地消耗致密小管系统并诱导EET产生。我们已经发现，5，6-EET诱导的Ca 2+进入需要基础水平的H2 O2，这可能保持一个氧化还原状态有利于这一事件。最后，我们的研究结果表明，5，6-EET诱导酪氨酸激酶蛋白的激活和肌动蛋白细胞骨架的重组，这可能提供了一个支持的运输部分的Ca 2+商店向PM，以促进从头IP 3R II型和hTRPC 1之间的耦合检测免疫共沉淀。我们建议，5，6-EET参与TG诱导的IP 3R II型和hTRPC 1之间的耦合，随后CCE是兼容的从头构象耦合在人类血小板。
A major pathway for Ca2+ entry in non-excitable cells is activated following depletion of intracellular Ca2+ stores. A de novo conformational coupling between elements in the plasma membrane (PM) and Ca2+ stores has been proposed as the most likely mechanism to activate this capacitative Ca2+ entry (CCE) in several cell types, including platelets. Here we report that a cytochrome P450 metabolite, 5,6-EET, might be a component of the de novo conformational coupling in human platelets. In these cells, 5,6-EET induces divalent cation entry without having any detectable effect on Ca2+ store depletion. 5,6-EET-induced Ca2+ entry was sensitive to the CCE blockers 2-APB, lanthanum, SKF-96365 and nickel and impaired by incubation with anti-hTRPC1 antibody. Ca2+ entry stimulated by low concentrations of thapsigargin, which selectively depletes the dense tubular system and induces EET production, was impaired by the cytochrome P450 inhibitor 17-ODYA, which has no effect on CCE mediated by depletion of the acidic stores using 2,5-di-(tert-butyl)-1,4-hydroquinone. We have found that 5,6-EET-induced Ca2+ entry requires basal levels of H2O2, which might maintain a redox state favourable for this event. Finally, our results indicate that 5,6-EET induces the activation of tyrosine kinase proteins and the reorganization of the actin cytoskeleton, which might provide a support for the transport of portions of the Ca2+ store towards the PM to facilitate de novo coupling between IP3R type II and hTRPC1 detected by coimmunoprecipitation. We propose that the involvement of 5,6-EET in TG-induced coupling between IP3R type II and hTRPC1 and subsequently CCE is compatible with the de novo conformational coupling in human platelets.