Differential affinities of visual arrestin, βarrestin1, and βarrestin2 for G protein-coupled receptors delineate two major classes of receptors
Differential affinities of visual arrestin, βarrestin1, and βarrestin2 for G protein-coupled receptors delineate two major classes of receptors
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DOI：
10.1074/jbc.m910348199
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发表时间：
2000-06-02
影响因子：
4.8
通讯作者：
Barak, LS
中科院分区：
文献类型：
--
作者：
Oakley, RH;Laporte, SA;Barak, LS
视觉抑制蛋白、β -抑制蛋白1和β -抑制蛋白2组成了一个细胞内蛋白家族，可使G蛋白偶联受体（gpcr）脱敏。此外，β -抑制蛋白1和β -抑制蛋白2将脱敏受体靶向到网格蛋白包被的凹坑中进行内吞作用。在本研究中，我们使用绿色荧光蛋白标记的阻滞蛋白，实时观察阻滞蛋白家族成员与gpcr的相互作用。在没有激动剂的情况下，HEK-293细胞的细胞质和细胞核中都发现了视觉阻滞蛋白和β -阻滞蛋白1，而β -阻滞蛋白2仅在细胞质中发现。通过对激动剂介导的抑制素转运到多个gpcr的分析，发现了两大类受体，A类受体（β 2肾上腺素能受体、mu阿片受体、内皮素A型受体、多巴胺D1A受体和alb肾上腺素能受体）结合β -抑制素2的亲和力高于β -抑制素1，且不与视觉抑制素相互作用。促甲状腺激素释放激素受体和P物质受体)以相似的高亲和力结合-抑制素亚型，并与视觉抑制素相互作用。切换A类和B类受体的羧基末端完全逆转了每个受体对视觉和非视觉拦阻蛋白的亲和力，此外，交换β -拦阻蛋白1和β -拦阻蛋白2的羧基末端逆转了它们与A类受体的结合程度以及它们的亚细胞分布。这些结果首次揭示了阻滞蛋白家族成员在质膜上与gpcr结合能力的显著差异，并且表明视觉阻滞蛋白可以在细胞中与视紫红质以外的gpcr相互作用。这些发现表明，GPCR信号可能受到不同的调控，这取决于阻滞蛋白异构体的细胞补体和阻滞蛋白与其他细胞蛋白相互作用的能力。
Visual arrestin, beta arrestin1, and beta arrestin2 comprise a family of intracellular proteins that desensitize G protein-coupled receptors (GPCRs), In addition, beta arrestin1 and beta arrestin2 target desensitized receptors to clathrin-coated pits for endocytosis. Whether arrestins differ in their ability to interact with GPCRs in cells is not known, In this study, we visualize the interaction of arrestin family members with GPCRs in real time and in live cells using green fluorescent protein-tagged arrestins, In the absence of agonist, visual arrestin and beta arrestin1 were found in both the cytoplasm and nucleus of HEK-293 cells, whereas beta arrestin2 was found only in the cytoplasm. Analysis of agonist-mediated arrestin translocation to multiple GPCRs identified two major classes of receptors, Class A receptors (beta 2 adrenergic receptor, mu opioid receptor, endothelin type A receptor, dopamine D1A receptor, and alb adrenergic receptor) bound beta arrestin2 with higher affinity than beta arrestin1 and did not interact with visual arrestin, In contrast, class B receptors (angiotensin II type 1A receptor, neurotensin receptor 1, vasopressin V2 receptor, thyrotropin-releasing hormone receptor, and substance P receptor) bound both beta arrestin isoforms with similar high affinities and also interacted with visual arrestin. Switching the carboxyl-terminal tails of class A and class B receptors completely reversed the affinity of each receptor for the visual and non-visual arrestins, In addition, exchanging the beta arrestin1 and beta arrestin2 carboxyl termini reversed their extent of binding to class A receptors as well as their subcellular distribution. These results reveal for the first time marked differences in the ability of arrestin family members to bind GPCRs at the plasma membrane, Moreover, they show that visual arrestin can interact in cells with GPCRs other than rhodopsin. These findings suggest that GPCR signaling may be differentially regulated depending on the cellular complement of arrestin isoforms and the ability of arrestins to interact with other cellular proteins.