Sphingosine 1-phosphate formation and intracellular Ca2+ mobilization in human platelets: evaluation with sphingosine kinase inhibitors.
Sphingosine 1-phosphate formation and intracellular Ca2+ mobilization in human platelets: evaluation with sphingosine kinase inhibitors.
复制标题
人血小板中 1-磷酸鞘氨醇的形成和细胞内 Ca2+ 动员：用鞘氨醇激酶抑制剂进行评估。
DOI：
10.1093/oxfordjournals.jbchem.a022440
复制
发表时间：
1999
影响因子：
2.7
通讯作者：
Y. Ozaki
中科院分区：
文献类型：
--
作者：
Libo Yang;Yutaka Yatomi;K. Satoh;Yasuyuki Igarashi;Y. Ozaki
Sphingosine 1-phosphate （Sph-1-P）被认为在细胞信号传导中起双重作用，作用于细胞间和细胞内。在这项研究中，我们使用dl -三氢鞘氨醇（DHS）和N，N-二甲基鞘氨醇（DMS）作为Sph激酶和蛋白激酶c的抑制剂，研究了Sph-1- p在人血小板中的信号分子作用。DMS和dl -三氢鞘氨醇（DMS）从血小板细胞质中分离得到Sph激酶的竞争性抑制剂。在以[3H]Sph标记的完整血小板中，12- o -十四烷酰磷13-醋酸酯或凝血酶刺激不影响[3H]-Sph-1-P的形成。DMS和DL-threo-DHS不仅抑制[3H]Sph-1-P的形成，还抑制蛋白激酶c依赖性血小板聚集，而staurosporine（一种有效的蛋白激酶抑制剂）仅抑制蛋白激酶c依赖性反应。因此，Sph激酶的激活和由此产生的Sph-1- p的形成不太可能是由血小板中的蛋白激酶C介导的。此外，作用于G蛋白偶联受体的血小板激动剂诱导的Ca2+动员不受DMS或DL-threo-DHS的影响。我们的研究结果表明，Sph-1-P不介导血小板中的细胞内信号传导，包括Ca2+动员。
Sphingosine 1-phosphate (Sph-1-P) is considered to play a dual role in cellular signaling, acting intercellularly as well as intracellularly. In this study, we examined the role of Sph-1-P as a signaling molecule in human platelets, using DL-threo-dihydrosphingosine (DHS) and N,N-dimethylsphingosine (DMS), inhibitors of Sph kinase and protein kinase C. Both DMS and DL-threo-DHS were confirmed to be competitive inhibitors of Sph kinase obtained from platelet cytoplasmic fractions. In intact platelets labeled with [3H]Sph, stimulation with 12-O-tetradecanoylphorbol 13-acetate or thrombin did not affect [3H]-Sph-1-P formation. While both DMS and DL-threo-DHS inhibited not only [3H]Sph-1-P formation but also protein kinase C-dependent platelet aggregation, staurosporine, a potent protein kinase inhibitor, only inhibited the protein kinase C-dependent reaction. Hence, it is unlikely that Sph kinase activation and the resultant Sph-1-P formation are mediated by protein kinase C in platelets. Furthermore, Ca2+ mobilization induced by platelet agonists that act on G protein-coupled receptor was not affected by DMS or DL-threo-DHS. Our results suggest that Sph-1-P does not mediate intracellular signaling, including Ca2+ mobilization, in platelets.