Comparison of intrinsic activities of the putative sphingosine 1-phosphate receptor subtypes to regulate several signaling pathways in their cDNA-transfected Chinese hamster ovary cells
Comparison of intrinsic activities of the putative sphingosine 1-phosphate receptor subtypes to regulate several signaling pathways in their cDNA-transfected Chinese hamster ovary cells
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DOI：
10.1074/jbc.274.34.23940
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发表时间：
1999-08-20
影响因子：
4.8
通讯作者：
Okajima, F
中科院分区：
文献类型：
--
作者：
Kon, J;Sato, K;Okajima, F
我们研究了鞘氨醇L-磷酸(S1P)在中国仓鼠卵巢细胞中对S1P受体亚型(即EDG-1、AGR16/H2 18(EDG-5)和EDG-3)转染的信号通路的作用。通过[SH]S1P与细胞的结合判断，在这些受体转导的细胞中，S1P受体的表达数量及其与S1P的亲和力没有显著差异。在载体转染组，S1P使胞浆内钙离子浓度([Ca2+](I))轻微升高，与肌醇磷酸生成有关，反映了磷脂酶C的激活；在EDG-3转染组和AGR16转染组，S1P诱导的作用明显增强。与载体转染组相比，EDG-1转染组细胞内S1P诱导的[Ca~(2+)](I)升高也略有增加。百日咳毒素(PTS)可部分抑制肌醇磷酸和钙离子对S1P的反应。S1P还以PTX不敏感的方式显著增加所有转染组细胞中cAMP的含量；S1P受体亚型的内在活性顺序为：AGR16>；EDG-3>；EDG-1。然而，在Forskolin的存在下，S1P在较低浓度(1-100 nM)的S1P以对PTX敏感的方式显著抑制EDG-1转基因细胞中cAMP的积累，而在EDG-3或AGR16转基因细胞中则不明显。用细胞数评价细胞在盲孔Boyden小室的迁移活性，EDG-1和EDG-3同样有效，而AGR16无效。因此，根据受体亚型的不同，S1P受体可能与PTX敏感和不敏感的G蛋白偶联，导致磷脂酶C-钙系统、腺苷环化酶cAMP系统和细胞迁移活性的选择性调节。
We examined the actions of sphingosine l-phosphate (S1P) on signaling pathways in Chinese hamster ovary cells transfected with putative S1P receptor subtypes, i.e. Edg-1, AGR16/H218 (Edg-5), and Edg-3. Among these receptor-transfected cells, there was no significant difference in the expressing numbers of the S1P receptors and their affinities to S1P, which were estimated by [SH]S1P binding to the cells. In vector-transfected cells, S1P slightly increased cytosolic Ca2+ concentration ([Ca2+](i)) in association with inositol phosphate production, reflecting phospholipase C activation; the S1P-induced actions were markedly enhanced in the Edg-3-transfected cells and moderately so in the AGR16-transfected cells. In comparison with vector-transfected cells, the S1P-induced [Ca2+](i) increase was also slightly enhanced in the Edg-1-transfected cells. In all cases, the inositol phosphate and Ca2+ responses to S1P were partially inhibited by pertussis toxin (PTS). S1P also significantly increased cAMP content in a PTX-insensitive manner in all the transfected cells; the rank order of their intrinsic activity of S1P receptor subtypes was AGR16 > Edg-3 > Edg-1. In the presence of forskolin, however, S1P significantly inhibited cAMP accumulation at a lower concentration (1-100 nM) of S1P in a manner sensitive to PTX in the Edg-1-transfected cells but not in either the Edg-3 or AGR16-transfected cells. As for cell migration activity evaluated by cell number across the filter of blind Boyden chamber, Edg-1 and Edg-3 were equally potent, but AGR16 was ineffective. Thus, S1P receptors may couple to both PTX-sensitive and -insensitive G-proteins, resulting in the selective regulation of the phospholipase C-Ca2+ system, adenylyl cyclase cAMP system, and cell migration activity, according to the receptor subtype.