FUNCTIONAL RECONSTITUTION OF PURIFIED MUSCARINIC RECEPTORS AND INHIBITORY GUANINE-NUCLEOTIDE REGULATORY PROTEIN
FUNCTIONAL RECONSTITUTION OF PURIFIED MUSCARINIC RECEPTORS AND INHIBITORY GUANINE-NUCLEOTIDE REGULATORY PROTEIN
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作者：
HAGA, K;HAGA, T;UI, M
毒蕈碱受体触发几种不同的反应，包括环GMP浓度的增加、环AMP浓度的降低、聚磷酸肌醇的分解和离子渗透性的变化。目前尚不清楚这些反应是顺序发生还是独立发生，以及哪些反应直接与毒蕈碱受体偶联。几条证据表明，在许多（如果不是全部）细胞类型中的毒蕈碱受体与腺苷酸环化酶的抑制性鸟嘌呤核苷酸调节蛋白（Nior Gi）偶联。为了提供这种耦合的直接证据，我们重建了从猪脑纯化的毒蕈碱受体与Nipurified从大鼠脑中的磷脂囊泡。在这里，我们报告的GTdR活性的Ni是由卡巴胆碱刺激。这一作用被同时加入阿托品阻断，当Niprotein被ADP-核糖基化时未观察到。我们得出结论，毒蕈碱受体的功能之一是激活镍。
Muscarinic receptors trigger several different responses including an increase in concentration of cyclic GMP, a decrease in cyclic AMP concentration, breakdown of polyphosphoinositides and changes in ion permeability. It is not yet clear whether these reactions occur sequentially or independently and which directly coupled to the muscarinic receptor. Several lines of evidence indicate that muscarinic receptors in many, if not all, cell types are coupled to the inhibitory guanine nucleotide regulatory protein (Nior Gi) of adenylate cyclase. To provide direct evidence for this coupling, we have reconstituted muscarinic receptors purified from porcine brain with Nipurified from rat brain in a phospholipid vesicle. Here, we report that the GTPase activity of Niis stimulated by carbachol. This action is blocked by the simultaneous addition of atropine and is not observed when the Niprotein is ADP-ribosylated. We conclude that one function of the muscarinic receptor is the activation of Ni.