Activation of phospholipase C by alpha 1-adrenergic receptors is mediated by the alpha subunits of Gq family.
Activation of phospholipase C by alpha 1-adrenergic receptors is mediated by the alpha subunits of Gq family.
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DOI：
10.1016/s0021-9258(18)35680-1
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发表时间：
1992-12
期刊：
影响因子：
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通讯作者：
Dianqing Wu;A. Katz;C. Lee;Melvin I. Simon
中科院分区：
文献类型：
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作者：
Dianqing Wu;A. Katz;C. Lee;Melvin I. Simon
Cos-7 细胞的高效瞬时转染先前用于建立 G α q/G α 11 和磷脂酶 C β 1 之间的功能偶联（Wu, D.、Lee, C-H.、Rhee, S. G. 和 Simon, M. I. (1992) J. Biol. Chem. 267, 1811-1817）。这里使用同一系统来研究其他鸟嘌呤核苷酸结合调节蛋白（G 蛋白）α 亚基和磷脂酶之间的功能耦合，并研究哪些 G α 亚基介导 α 1 肾上腺素能受体亚型（α 1 A、α 1 B 和 α 1 C）对磷脂酶 C 的激活。我们发现 G α 14 和 G α 16 的行为类似于 G α 11 或 G alpha q，即在 AIFn 存在的情况下，它们可以激活 Cos-7 细胞中的内源磷脂酶。 Cos-7细胞共转染编码Gα亚基和磷脂酶Cβ1的cDNA后，Cos-7细胞中肌醇磷酸盐释放的协同增加表明Gα16和Gα14都可以激活磷脂酶Cβ1。磷脂酶Cβ1的激活仅限于α亚基的Gq亚家族的成员。他们激活磷脂酶 C beta 1，但不激活磷脂酶 C gamma 1、gamma 2 或磷脂酶 C delta 3。 Cos-7 细胞与编码三种不同 α 1 肾上腺素受体和 G α q 或 G α 11 的 cDNA 共转染，导致去甲肾上腺素依赖性肌醇磷酸盐释放增加。这表明G α q 或G α 11 可以介导α 1-肾上腺素能受体的所有三种亚型对磷脂酶C的激活。使用相同的测定系统，G α 16 和 G α 14 似乎不同地参与 α 1-肾上腺素能受体对磷脂酶 C 的激活。 α1B亚型受体在共转染Gα14或Gα16的细胞中产生配体介导的协同反应。然而，α1C受体在共转染Gα14但不转染Gα16的细胞中产生反应，而α1A受体在转染Gα14或Gα16的细胞中几乎没有表现出协同反应。 1 A 和 alpha 1 C 受体通过 G alpha q 和 G alpha 11 激活磷脂酶 C 也在无细胞系统中得到证实。（摘要截断为 400 字）
High efficiency transient transfection of Cos-7 cells was previously used to establish the functional coupling between G alpha q/G alpha 11 and phospholipase C beta 1 (Wu, D., Lee, C-H., Rhee, S. G., and Simon, M. I. (1992) J. Biol. Chem. 267, 1811-1817). Here the same system was used to study the functional coupling between other guanine nucleotide-binding regulatory protein (G-protein) alpha subunits and phospholipases and to study which G alpha subunits mediate the activation of phospholipase C by the alpha 1-adrenergic receptor subtypes, alpha 1 A, alpha 1 B, and alpha 1 C. We found that G alpha 14 and G alpha 16 behaved like G alpha 11 or G alpha q, i.e. they could activate endogenous phospholipases in Cos-7 cells in the presence of AIFn. The synergistic increase in inositol phosphate release in Cos-7 cells after they were cotransfected with cDNAs encoding G alpha subunits and phospholipase C beta 1 indicates that both G alpha 16 and G alpha 14 can activate phospholipase C beta 1. The activation of phospholipase C beta 1 was restricted to members of the Gq subfamily of alpha subunits. They activated phospholipase C beta 1 but not phospholipase C gamma 1, gamma 2, or phospholipase C delta 3. The cotransfection of Cos-7 cells with cDNAs encoding three different alpha 1-adrenergic receptors and G alpha q or G alpha 11 leads to an increase in norepinephrine-dependent inositol phosphate release. This indicates that G alpha q or G alpha 11 can mediate the activation of phospholipase C by all three subtypes of alpha 1-adrenergic receptors. With the same assay system, G alpha 16 and G alpha 14 appear to be differentially involved in the activation of phospholipase C by the alpha 1-adrenergic receptors. The alpha 1 B subtype receptor gave a ligand-mediated synergistic response in the cells cotransfected with either G alpha 14 or G alpha 16. However, the alpha 1 C receptor responded in cells cotransfected with G alpha 14 but not G alpha 16, and the alpha 1 A receptor showed little synergistic response in cells transfected with either G alpha 14 or G alpha 16. The ability of the alpha 1 A and alpha 1 C receptors to activate phospholipase C through G alpha q and G alpha 11 was also demonstrated in a cell-free system.(ABSTRACT TRUNCATED AT 400 WORDS)