Evidence for dual coupling of the murine luteinizing hormone receptor to adenylyl cyclase and phosphoinositide breakdown and Ca2+ mobilization. Studies with the cloned murine luteinizing hormone receptor expressed in L cells.
Evidence for dual coupling of the murine luteinizing hormone receptor to adenylyl cyclase and phosphoinositide breakdown and Ca2+ mobilization. Studies with the cloned murine luteinizing hormone receptor expressed in L cells.
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DOI：
10.1016/s0021-9258(18)42858-x
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发表时间：
1992-03
期刊：
影响因子：
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通讯作者：
Thomas Gudermann;Mariel Birnbaumer;Lutz Birnbaumer
中科院分区：
文献类型：
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作者：
Thomas Gudermann;Mariel Birnbaumer;Lutz Birnbaumer
克隆了小鼠促黄体激素受体（LHR），并在L细胞中表达。这种LHR（674个氨基酸的成熟蛋白质）与大鼠的LHR非常相似（相同长度，36个氨基酸差异），但与人类的LHR（673个氨基酸，109个差异）有显著差异。小鼠LHR在L细胞中的表达导致人绒毛膜促性腺激素（hCG）结合位点的出现，Kd为150 pM，LH和hCG可刺激腺苷酸环化酶活性（EC 50 = 50-100 pM hCG）。在用[3 H]肌醇标记磷酸肌醇后，表达鼠LHR的L细胞对hCG产生反应，其磷酸肌醇水解速率增加（EC 50 = 2，400 pM hCG）。这是伴随着细胞内Ca 2 + [（Ca 2 +]i）的增加，由Fura 2方法确定。这种[Ca ~（2+）]i的增加依赖于LHR，因为在不表达LHR的L细胞中，HCG不影响[Ca ~（2+）]i。这种作用不是由于LH受体的cAMP形成活性，因为无论是毛喉素还是前列腺素E1，都可以增加L细胞中的cAMP水平，在对照或LHR表达细胞中具有类似的作用，异丙肾上腺素在表达功能活性仓鼠β-肾上腺素能受体的L细胞中没有作用。这种效应也不是由于GS偶联受体的过表达，因为表达8倍高水平的人V2加压素受体的L细胞不能模拟LH受体的Ca（2+）动员反应。我们得出结论，LH受体具有激活两种细胞内信号通路的能力：一种导致腺苷酸环化酶的刺激，导致cAMP的增加，第二种导致磷脂酶C的刺激，导致磷酸肌醇的形成和[Ca 2 +]i的升高。这些数据与先前关于hCG动员黄体和颗粒细胞中磷酸肌醇和增加[Ca 2 +]i的能力的报道（例如Davis，J.S.，韦斯特湖一、和Farese，R. V.（1984）J.Biol.Chem.259，15028-15034）。
The murine receptor for luteinizing hormone (LHR) was cloned and expressed in L cells. This LHR (mature protein of 674 amino acids) is very similar to that of the rat (same length, 36 amino acid differences) but differs significantly more from that of man (673 amino acids, 109 differences). Expression of the murine LHR in L cells led to the appearance of binding sites for human chorionic gonadotropin (hCG) with a Kd of 150 pM and an LH- and hCG-stimulable adenylyl cyclase activity (EC50 = 50-100 pM hCG). Upon labeling pools of phosphoinositides with [3H]myo-inositol, L cells expressing the murine LHR responded to hCG with an increase in their rate of phosphoinositide hydrolysis (EC50 = 2,400 pM hCG). This was accompanied by an increase in intracellular Ca2+ [( Ca2+]i), as determined by the Fura2 method. This increase in [Ca2+]i in response to hCG was dependent on the LHR, for HCG did not affect [Ca2+]i in L cells not expressing the LHR. The effect was not due to the cAMP-forming activity of the LH receptor, for neither forskolin nor prostaglandin E1, which both increase cAMP levels in L cells, had a similar effect in either control or LHR-expressing cells and isoproterenol had no effect in L cells expressing a functionally active hamster beta-adrenergic receptor. The effect was also not due to overexpression of a Gs-coupled receptor, for L cells expressing 8-fold higher levels of the human V2 vasopressin receptor did not mimic the Ca(2+)-mobilizing response of the LH receptor. We conclude that the LH receptor has the capability of activating two intracellular signaling pathways: one leading to stimulation of adenylyl cyclase and resulting in increases in cAMP and a second leading to stimulation of phospholipase C and resulting in formation of inositol phosphates and elevations in [Ca2+]i. These data correlate positively with and provide a mechanistic explanation for previous reports on the ability of hCG to mobilize phosphoinositides and increasing [Ca2+]i in luteal and granulosa cells (e.g. Davis, J. S., West, L. A., and Farese, R. V. (1984) J. Biol. Chem. 259, 15028-15034).