Heterooligomerization of human dopamine receptor 2 and somatostatin receptor 2 - Co-immunoprecipitation and fluorescence resonance energy transfer analysis
Heterooligomerization of human dopamine receptor 2 and somatostatin receptor 2 - Co-immunoprecipitation and fluorescence resonance energy transfer analysis
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DOI：
10.1016/j.cellsig.2007.07.007
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发表时间：
2007-11-01
影响因子：
4.8
通讯作者：
Kumar, Ujendra
中科院分区：
文献类型：
--
作者：
Baragli, Alessandra;Alturaihi, Haydar;Kumar, Ujendra
生长抑素和多巴胺受体在多个大脑区域中得到良好表达并共定位，这表明功能相互作用的可能性。在本研究中，我们结合药理学、生化和光漂白荧光共振能量转移 (pbFRET) 来确定共转染的 CHO-K1 或 HEK-293 细胞以及内源表达两种受体的培养神经元细胞中人生长抑素受体 2 (hSSTR2) 和人多巴胺受体 2 (hD2R) 之间的功能相互作用。在单转染的 CHO-K1 或 HEK-293 细胞中，D2R 以预先形成的二聚体形式存在，对激动剂或拮抗剂治疗不敏感。在与 hD2R 和 hSSTR2 稳定共转染的对照 CHO-K1 细胞中，HEK-293 细胞的免疫共沉淀物中相对较低的 FRET 效率和较弱的表达表明不存在预先形成的异寡聚体。然而，在用选择性配体处理后，hD2R 和 hSSTR2 表现出异二聚化。激动剂诱导的异二聚化伴随着对多巴胺的亲和力增加、hD2R信号传导增强以及hSSTR2内化时间延长。相比之下，培养的纹状体神经元表现出 D2R 和 SSTR2 之间的组成型异二聚化，这是不依赖激动剂的。然而，在 D2R 拮抗剂艾氯必利存在下，神经元中的异二聚化被完全消除。这些发现表明，hD2R 和 hSSTR2 作为由配体原位调节的功能性异二聚体起作用，这可能被证明是设计新治疗药物的有用模型。 (C) 2007 Elsevier Inc. 保留所有权利。
Somatostatin and dopamine receptors are well expressed and co-localized in several brain regions, suggesting the possibility of functional interactions. In the present study we used a combination of pharmacological, biochemical and photobleaching fluorescence resonance energy transfer (pbFRET) to determine the functional interactions between human somatostatin receptor 2 (hSSTR2) and human dopamine receptor 2 (hD2R) in both co-transfected CHO-K1 or HEK-293 cells as well as in cultured neuronal cells which express both the receptors endogenously. In monotransfected CHO-K1 or HEK-293 cells, D2R exists as a preformed dimer which is insensitive to agonist or antagonist treatment. In control CHO-K1 cells stably co-transfected with hD2R and hSSTR2, relatively low FRET efficiency and weak expression in co-immunoprecipitate from HEK-293 cells suggest the absence of preformed heterooligomers. However, upon treatment with selective ligands, hD2R and hSSTR2 exhibit heterodimerization. Agonist-induced heterodimerization was accompanied by increased affinity for dopamine and augmented hD2R signalling as well as prolonged hSSTR2 internalization. In contrast, cultured striatal neurons display constitutive heterodimerization between D2R and SSTR2, which were agonist-independent. However, heterodimerization in neurons was completely abolished in the presence of the D2R antagonist eticlopride. These findings suggest that hD2R and hSSTR2 operate as functional heterodimers modulated by ligands in situ, which may prove to be a useful model in designing new therapeutic drugs. (C) 2007 Elsevier Inc. All rights reserved.