Wang C, Zhou D, Cheng Z, Wei Q, Chen J, Li G, Pei G, Chi Z
Shanghai Institute of Materia Medica, Shanghai Institute of Cell Biology, Chinese Academy of Sciences, 294 Tai-yuan Road, Shanghai, 200031, People's Republic of China.
Biochem Biophys Res Commun. 1998 Aug 19;249(2):321-4. doi: 10.1006/bbrc.1998.9080.
The agonist-dependent activation and desensitization of a recombinant analog of delta-opioid receptor lacking the carboxyl-terminal (C-terminal) 31 residue peptide segment were discussed. The cDNA of the C-truncated delta-opioid receptor was created by polymerase chain reaction (PCR), stably expressed in Chinese hamster ovary cells and characterized by binding assay and function assay. Agonist [D-Pen2, D-Pen5]-enkephalin (DPDPE) stimulated the specific [35S]GTPgammaS binding to membrane fragments of cells expressing the C-truncated and the wild-type delta-opioid receptors in different levels dose-dependently. EC50 values of DPDPE on truncated and wild-types in stimulation were very similar. Agonist-dependent desensitization, which could be blocked by protein kinase inhibitor staurosporine (Stau), was observed after pretreating truncated receptors with 1 microM DPDPE for 10 min, the same as wild-types. The results reveal that the C-terminal of the delta-opioid receptor is not involved in controlling the G-protein activation and phosphorylation-related functional desensitization.
本文讨论了缺少羧基末端（C末端）31个残基肽段的δ-阿片受体重组类似物的激动剂依赖性激活和脱敏作用。通过聚合酶链反应（PCR）构建了C末端截短的δ-阿片受体cDNA，在中国仓鼠卵巢细胞中稳定表达，并通过结合试验和功能试验进行表征。激动剂[D-Pen2，D-Pen5]-脑啡肽（DPDPE）以不同水平剂量依赖性地刺激了特异性[35S]GTPγS与表达C末端截短型和野生型δ-阿片受体的细胞膜片段的结合。DPDPE在刺激截短型和野生型受体时的EC50值非常相似。在用1μM DPDPE预处理截短型受体10分钟后，观察到激动剂依赖性脱敏，这与野生型受体一样，可被蛋白激酶抑制剂星形孢菌素（Stau）阻断。结果表明，δ-阿片受体的C末端不参与控制G蛋白激活和磷酸化相关的功能性脱敏。
