Klingler C, Ancellin N, Barrault M B, Morel A, Corman B
Service de Biologie Cellulaire, CEA, Centre d'Etudes de Saclay, Gif-sur-Yvette, 91191 Cedex, France.
Biochem J. 1998 Mar 1;330 ( Pt 2)(Pt 2):1023-8. doi: 10.1042/bj3301023.
Cross-talk between the phospholipase C and adenylyl cyclase signalling pathways was investigated in Chinese hamster ovary (CHO) cells transfected with the V1a and V2 vasopressin receptors. Cell lines expressing V1a, V2, or both V1a and V2 receptors, were established and characterized. Stimulation of V2 receptors by vasopressin induced a dose-dependent increase in cAMP accumulation, whereas stimulation of V1a receptor resulted in an increase in intracellular calcium without any change in basal cAMP. The simultaneous stimulation of V2 and V1a receptors by vasopressin elicited an intracellular cAMP accumulation which was twice that induced by stimulation of V2 receptor alone with deamino-[d-Arg8]vasopressin. This potentiation between V1a and V2 receptors was mimicked by activation of protein kinase C (PKC) with PMA, and was suppressed when PKC activity was inhibited by bisindolylmaleimide. The potentiation was observed in the presence or absence of 1 mM 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, implying that an alteration in cAMP hydrolysis was not involved. Vasopressin, as well as PMA, had no effect on the forskolin-induced cAMP accumulation, suggesting that PKC did not directly stimulate the cyclase activity. On the other hand, vasopressin, like PMA, potentiated the cAMP accumulation induced by cholera toxin, an activator of Galphas protein. These results suggest that, in CHO cells, vasopressin V1a receptor potentiates the cAMP accumulation induced by the V2 receptor through a PKC-dependent increase in the coupling between Gs protein and adenylyl cyclase.
在转染了 V1a 和 V2 血管加压素受体的中国仓鼠卵巢（CHO）细胞中，研究了磷脂酶 C 和腺苷酸环化酶信号通路之间的相互作用。建立并鉴定了表达 V1a、V2 或同时表达 V1a 和 V2 受体的细胞系。血管加压素刺激 V2 受体可诱导 cAMP 积累呈剂量依赖性增加，而刺激 V1a 受体则导致细胞内钙增加，基础 cAMP 无变化。血管加压素同时刺激 V2 和 V1a 受体可引起细胞内 cAMP 积累，其是单独用脱氨基 - [d - Arg8]血管加压素刺激 V2 受体所诱导积累的两倍。V1a 和 V2 受体之间的这种增强作用可被 PMA 激活蛋白激酶 C（PKC）所模拟，而当 PKC 活性被双吲哚马来酰胺抑制时则受到抑制。在存在或不存在 1 mM 3 - 异丁基 - 1 - 甲基黄嘌呤（一种磷酸二酯酶抑制剂）的情况下均观察到这种增强作用，这意味着不涉及 cAMP 水解的改变。血管加压素以及 PMA 对福斯可林诱导的 cAMP 积累均无影响，表明 PKC 未直接刺激环化酶活性。另一方面，血管加压素与 PMA 一样，增强了霍乱毒素（一种 Gαs 蛋白激活剂）诱导的 cAMP 积累。这些结果表明，在 CHO 细胞中，血管加压素 V1a 受体通过 PKC 依赖性增加 Gs 蛋白与腺苷酸环化酶之间的偶联，增强了 V2 受体诱导的 cAMP 积累。
