Oligomerization of μ- and δ-opioid receptors -: Generation of novel functional properties
Oligomerization of μ- and δ-opioid receptors -: Generation of novel functional properties
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DOI：
10.1074/jbc.m000345200
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发表时间：
2000-08-25
影响因子：
4.8
通讯作者：
O'Dowd, BF
中科院分区：
文献类型：
--
作者：
George, SR;Fan, T;O'Dowd, BF
我们和其他人已经描述了许多G蛋白偶联受体的二聚体和寡聚体的存在。由于许多G蛋白偶联受体亚型彼此高度同源，我们研究了密切相关的受体是否可以直接相互作用，从而有可能创造新的信号单元。使用μ-和δ-阿片受体，我们表明，每个受体单独表达是不同的，可以可视化电泳后单体，同源二聚体，同源四聚体，和更高分子量的寡聚体。当μ-和δ-阿片受体共表达时，每种受体的高选择性合成激动剂的效力降低，等级顺序改变，而内吗啡肽-1和Leu-脑啡肽的亲和力增强，表明形成了一种新的结合口袋。通过可用的方法，在共表达μ-和δ-受体的膜中未观察到异二聚体。然而，通过使用差异表位标记的受体使μ-受体与δ-受体共免疫沉淀的能力来鉴定异源寡聚体，反之亦然。与单独表达的μ-和δ-受体相反，共表达的受体显示出对百日咳毒素的不敏感性和持续的信号转导，这可能是由于与不同亚型的G蛋白的相互作用。在这项研究中，我们首次提供了μ-和δ-阿片受体形成寡聚体的直接相互作用的证据，并产生了新的药理学和G蛋白偶联特性。
The existence of dimers and oligomers for many G protein-coupled receptors has been described by us and others. Since many G protein-coupled receptor subtypes are highly homologous to each other, we examined whether closely related receptors may interact with each other directly and thus have the potential to create novel signaling units. Using mu- and delta-opioid receptors, we show that each receptor expressed individually was pharmacologically distinct and could be visualized following electrophoresis as monomers, homodimers, homotetramers, and higher molecular mass oligomers. When mu- and delta-opioid receptors were coexpressed, the highly selective synthetic agonists for each had reduced potency and altered rank order, whereas endomorphin-1 and Leu-enkephalin had enhanced affinity, suggesting the formation of a novel binding pocket. No heterodimers were visualized in the membranes coexpressing mu- and delta-receptors by the methods available. However, heterooligomers were identified by the ability to co-immunoprecipitate mu-receptors with delta-receptors and vice versa using differentially epitope-tagged receptors, In contrast to the individually expressed mu- and delta-receptors, the coexpressed receptors showed insensitivity to pertussis toxin and continued signal transduction, likely due to interaction with a different subtype of G protein. In this study, we provide, for the first time, evidence for the direct interaction of mu- and delta-opioid receptors to form oligomers, with the generation of novel pharmacology and G protein coupling properties.