Offermanns S, Schultz G, Rosenthal W
Institut für Pharmakologie, Freie Universität Berlin, Federal Republic of Germany.
J Biol Chem. 1991 Feb 25;266(6):3365-8.
In membranes of neuroblastoma x glioma (NG108-15) hybrid cells, the photoreactive GTP analog, [alpha-32P] GTP azidoanilide, was incorporated into 39-41-kDa proteins comigrating in urea-containing sodium dodecyl sulfate-polyacrylamide gels with immunologically identified G-protein alpha-subunits, i.e. a 39-kDa Go alpha-subunit, a 40-kDa Gi2 alpha-subunit, and a 41-kDa Gi alpha-subunit of an unknown subtype. The synthetic opioid, D-Ala2,D-Leu5-enkephalin (DADLE), stimulated photolabeling of the 39-41-kDa proteins. In the presence of GDP, which increased the ratio of agonist-stimulated to basal photolabeling, DADLE at a maximally effective concentration stimulated photolabeling of the 39- and the 40-kDa protein 2-3-fold. Somatostatin, adrenaline, and bradykinin were less potent than DADLE and, to varying degrees, stimulated photolabeling of the 40-kDa protein more than that of the 39-kDa protein. Prostaglandin E1 was inactive. The present data represent direct evidence for an activation of endogenous Go and Gi2 via opioid receptors and other receptors in the native membrane milieu.
在神经母细胞瘤x胶质瘤（NG108-15）杂交细胞的膜中，光反应性GTP类似物[α-32P]GTP叠氮苯胺被掺入到分子量为39 - 41kDa的蛋白质中，这些蛋白质在含尿素的十二烷基硫酸钠-聚丙烯酰胺凝胶中与经免疫鉴定的G蛋白α亚基共迁移，即一种39kDa的Goα亚基、一种40kDa的Gi2α亚基以及一种未知亚型的41kDa的Giα亚基。合成阿片样物质D-Ala2,D-Leu5-脑啡肽（DADLE）刺激了这些39 - 41kDa蛋白质的光标记。在GDP存在的情况下，GDP增加了激动剂刺激的光标记与基础光标记的比率，最大有效浓度的DADLE刺激了39kDa和40kDa蛋白质的光标记2 - 3倍。生长抑素、肾上腺素和缓激肽的效力低于DADLE，并且在不同程度上，刺激40kDa蛋白质的光标记比39kDa蛋白质更多。前列腺素E1无活性。目前的数据代表了在天然膜环境中内源性Go和Gi2通过阿片受体和其他受体被激活的直接证据。
