Molecular cloning and characterization of a novel human G-protein-coupled receptor, EDG7, for lysophosphatidic acid
Molecular cloning and characterization of a novel human G-protein-coupled receptor, EDG7, for lysophosphatidic acid
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DOI：
10.1074/jbc.274.39.27776
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发表时间：
1999-09-24
影响因子：
4.8
通讯作者：
Inoue, K
中科院分区：
文献类型：
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作者：
Bandoh, K;Aoki, J;Inoue, K
溶血磷脂酸（LPA）与鞘氨醇l-磷酸一起是一种生物活性脂质介质，其作用于G蛋白偶联受体以引起多种细胞反应，包括Ca 2+动员、腺苷酸环化酶的调节和促分裂原活化蛋白（MAP）激酶活化。在这项研究中，我们分离了一个人的cDNA编码一种新的G蛋白偶联受体，命名为EDG 7，并将其作为LPA的细胞受体。EDG 7蛋白的氨基酸序列分别与先前鉴定的人功能性LPA受体EDGE和EDG 4的氨基酸序列有53.7%和48.8%相同。LPA（油酰基）而非其他溶血磷脂诱导EDG 7过表达Sf 9细胞[Ca 2 +]（i）增加。当在Sf 9细胞中表达时，其他LPA受体EDG 4而不是EDG 2通过LPA转导Ca 2+应答。具有不饱和脂肪酸但不具有饱和脂肪酸的LPAs诱导表达EDG 7的Sf 9细胞的[Ca 2 +]（i）增加，而具有饱和和不饱和脂肪酸的LPAs在表达EDG 4的Sf 9细胞中引起Ca 2+应答。在表达EDG 7或EDG 4的Sf 9细胞中，LPA刺激毛喉素诱导的细胞内cAMP水平增加，而在表达EDG 2的细胞中未观察到。在PC 12细胞中，EDG 4介导LPA激活MAP激酶，而EDG 2和EDG 7不介导LPA激活MAP激酶。无论是EDG 7，也不是EDG 4转导的Ca 2+反应或cAMP积累抑制百日咳毒素。总之，本研究表明，EDG 7，G-蛋白偶联受体的EDG家族的新成员，是一个特定的LPA受体，从已知的克隆LPA受体在配体特异性，Ca 2+反应，腺苷酸环化酶的调制，和MAP激酶激活显示不同的属性。
Lysophosphatidic acid (LPA), together with sphingosine l-phosphate, is a bioactive lipid mediator that acts on G-protein-coupled receptors to evoke multiple cellular responses, including Ca2+ mobilization, modulation of adenylyl cyclase, and mitogen-activated protein (MAP) kinase activation. In this study, we isolated a human cDNA encoding a novel G-protein-coupled receptor, designated EDG7, and characterized it as a cellular receptor for LPA. The amino acid sequence of the EDG7 protein is 53.7 and 48.8% identical to those of the human functional LPA receptors EDGE and EDG4, respectively, previously identified. LPA (oleoyl) but not other lysophospholipids induced an increase in the [Ca2+](i) of EDG7-overexpressing Sf9 cells. Other LPA receptors, EDG4 but not EDG2, transduced the Ca2+ response by LPA when expressed in Sf9 cells. LPAs with an unsaturated fatty acid but not with a saturated fatty acid induced an increase in the [Ca2+](i) of EDG7-expressing Sf9 cells, whereas LPAs with both saturated and unsaturated fatty acids elicited a Ca2+ response in Sf9 cells expressing EDG4. In EDG7- or EDG4-expressing Sf9 cells, LPA stimulated forskolin-induced increase in intracellular cAMP levels, which was not observed in EDG2-expressing cells. In PC12 cells, EDG4 but not EDG2 or EDG7 mediated the activation of MAP kinase by LPA. Neither the EDG7- nor EDG4-transduced Ca2+ response or cAMP accumulation was inhibited by pertussis toxin. In conclusion, the present study demonstrates that EDG7, a new member of the EDG family of G-protein-coupled receptors, is a specific LPA receptor that shows distinct properties from known cloned LPA receptors in ligand specificities, Ca2+ response, modulation of adenylyl cyclase, and MAP kinase activation.