Involvement of the βγ subunits of G proteins in the cAMP response induced by stimulation of the histamine H1 receptor
Involvement of the βγ subunits of G proteins in the cAMP response induced by stimulation of the histamine H1 receptor
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DOI：
10.1007/s00210-005-0001-x
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发表时间：
2005-08-01
影响因子：
3.6
通讯作者：
Ishii, K
中科院分区：
文献类型：
--
作者：
Maruko, T;Nakahara, T;Ishii, K
组胺H-1受体的刺激已被证明可增强各种细胞类型中腺苷3 '，5'-环一磷酸（cAMP）的积累，但迄今为止，发生这种情况的机制仍不清楚。在本研究中，我们研究的可能性，β γ亚基的G蛋白（G β γ）参与这一过程中培养的中国仓鼠卵巢细胞转染的人组胺H-1受体（CHO-H-1）。组胺以浓度依赖性方式增加CHO-H-1细胞内cAMP水平，这种组胺作用被吡拉明（1 μ M）消除。通过稳定表达G α（q）蛋白C端肽抑制组胺H-1受体-G（q）蛋白偶联可显著减弱组胺诱导的cAMP蓄积。通过比较，无论是BAPTA/AM（50 μ M），细胞内钙离子螯合剂，也没有GF 109203 X（1 μ M），蛋白激酶C的抑制剂，影响cAMP的反应。组胺H-1受体介导的cAMP积累显着抑制瞬时转染CHO-H-1细胞与β-肾上腺素受体激酶I（残基542-685），清除剂G β γ的C-末端肽。稳定表达G α（s）蛋白的C-末端肽，但不用百日咳毒素处理（200 ng/ml，24 h），可减弱组胺H-1受体介导的cAMP蓄积。这些结果表明，组胺H-1受体的刺激激活腺苷酸环化酶通过释放G β γ亚单位从G蛋白，从而提高细胞内cAMP水平。
Stimulation of the histamine H-1 receptor has been shown to enhance adenosine 3', 5'-cyclic monophosphate (cAMP) accumulation in various cell types but, to date, the mechanism by which this occurs is still unclear. In the present study, we examined the possibility that the beta gamma subunits of G proteins (G beta gamma) are involved in this process in cultured Chinese hamster ovary cells transfected with the human histamine H-1 receptor (CHO-H-1). Histamine increased intracellular cAMP levels in a concentration-dependent manner in CHO-H-1 cells, and this histamine action was abolished by pyrilamine (1 mu M). Inhibition of histamine H-1 receptor-G(q) protein coupling by stable expression of the C-terminal peptide of G alpha(q) protein significantly attenuated the cAMP accumulation induced by histamine. By comparison, neither BAPTA/AM (50 mu M), an intracellular Ca2+ chelator, nor GF 109203X (1 mu M), an inhibitor of protein kinase C, influenced the cAMP response. Histamine H-1 receptor-mediated cAMP accumulation was significantly inhibited by transient transfection of CHO-H-1 cells with the C-terminal peptide of beta-adrenoceptor kinase I (residues 542-685), a scavenger of G beta gamma. Stable expression of the C-terminal peptide of the G alpha(s) protein, but not treatment with pertussis toxin (200 ng/ml for 24 h), attenuated the histamine H-1 receptor-mediated cAMP accumulation. These results suggest that stimulation of histamine H-1 receptors activates adenylyl cyclase through the release of G beta gamma subunits from G proteins, thereby elevating intracellular cAMP levels.