The lutropin/choriogonadotropin receptor-induced phosphorylation of the extracellular signal-regulated kinases in Leydig cells is mediated by a protein kinase A-dependent activation of Ras
The lutropin/choriogonadotropin receptor-induced phosphorylation of the extracellular signal-regulated kinases in Leydig cells is mediated by a protein kinase A-dependent activation of Ras
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DOI：
10.1210/me.2003-0205
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发表时间：
2003-11-01
影响因子：
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通讯作者：
Ascoli, M
中科院分区：
文献类型：
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作者：
Hirakawa, T;Ascoli, M
在表达重组人促黄体生成素受体(HLHR)的MA-10细胞和原代培养的大鼠间质细胞前体细胞中，检测了参与ERK1/2级联激活的途径。在表达重组hLHR的MA-10细胞中，人绒毛膜促性腺激素诱导的ERK1/2的激活可通过过表达cAMP磷酸二酯酶(一种钝化人绒毛膜促性腺激素诱导的cAMP反应的操作)、添加H89(蛋白激酶A的选择性抑制剂)或过表达热稳定的蛋白激酶A抑制剂来有效地抑制，但不能通过过表达该抑制物的非活性突变体来抑制。刺激hLHR不能激活RAP1，但以H89敏感的方式激活RAS。加入H89，几乎完全抑制hLHR介导的ERK1/2的激活。我们还发现，8-溴-cAMP以H89敏感的方式激活MA-10细胞和原代培养的大鼠间质细胞前体细胞中的RAS和ERK1/2，而cAMP类似物8-(4-氯苯硫基)-2‘-O-甲基-cAMP(8CPT-2Me-cAMP)对cAMP依赖的鸟核苷酸交换因子没有影响。综上所述，我们的结果表明，hLHR诱导的间质细胞ERK1/2的磷酸化是由蛋白激酶A依赖的RAS激活所介导的。
The pathways involved in activation of the ERK1/2 cascade in Leydig cells were examined in MA-10 cells expressing the recombinant human LH receptor (hLHR) and in primary cultures of rat Leydig cell precursors. In MA-10 cells expressing the recombinant hLHR, human choriogonadotropin-induced activation of ERK1/2 is effectively inhibited by overexpression of a cAMP phosphodiesterase ( a manipulation that blunts the human choriogonadotropin-induced cAMP response), by addition of H89 ( a selective inhibitor of protein kinase A), or by overexpression of the heat-stable protein kinase A inhibitor, but not by overexpression of an inactive mutant of this inhibitor. Stimulation of hLHR did not activate Rap1, but activated Ras in an H89-sensitive fashion. Addition of H89 to MA-10 cells that had been cotransfected with a guanosine triphosphatase-deficient mutant of Ras almost completely inhibited the hLHR-mediated activation of ERK1/2. We also show that 8-bromo-cAMP activates Ras and ERK1/2 in MA-10 cells and in primary cultures of rat Leydig cells precursors in an H89-sensitive fashion, whereas a cAMP analog 8-(4-chloro-phenylthio)-2'-O-methyl-cAMP (8CPT-2Me- cAMP) that is selective for cAMP-dependent guanine nucleotide exchange factor has no effect. Collectively, our results show that the hLHR-induced phosphorylation of ERK1/2 in Leydig cells is mediated by a protein kinase A-dependent activation of Ras.