Dopamine D1 and adenosine A1 receptors form functionally interacting heteromeric complexes
Dopamine D1 and adenosine A1 receptors form functionally interacting heteromeric complexes
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DOI：
10.1073/pnas.150241097
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发表时间：
2000-07-18
影响因子：
11.1
通讯作者：
Franco, R
中科院分区：
文献类型：
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作者：
Ginés, S;Hillion, J;Franco, R
先前描述的大脑中腺苷A(1)受体（A(1)R）和多巴胺D-1受体（D1R）之间拮抗相互作用的可能分子基础已经在小鼠成纤维细胞Ltk（-）细胞中进行了研究，这些细胞共转染了人A(1)R和D1R cdna或人A(1)R和多巴胺D-2受体（长形）（D2R） cdna，并在培养的皮质神经元中进行了研究。在共转染的成纤维细胞中发现A(1)R和D1R共免疫沉淀，而A(1)R和D2R不共免疫沉淀。这种选择性A(1)R/D1R异质化在D1R激动剂预处理后消失，但在D1R和A(1)R激动剂联合预处理后没有消失。在共聚焦激光显微镜双免疫荧光实验中发现，在共转染的成纤维细胞和皮层神经元中都存在高度的A(1)R和D1R共定位。另一方面，在共转染的成纤维细胞中观察到低程度的a (1)R和D2R共定位。A(1)R激动剂预处理导致A(1)R和D1R共聚集。在培养的成纤维细胞和皮质神经元中，D1R和A(1)R激动剂联合预处理可阻断其表达。联合预处理D1R和A(1)R激动剂，但不是单独使用任何一种，可以显著降低D1R激动剂诱导的cAMP积累。A(1)R/D1R异聚化可能是脑内D1R受体信号A(1)R拮抗调节的分子基础。A(1)R/D1R异构体的持续存在似乎是阻断A(1)R激动剂诱导的A(1)R/D1R共聚和D1R激动剂联合预处理时D1R激动剂诱导的cAMP积累脱敏所必需的，这表明A(1)R/D1R异构体在脱敏机制和受体运输中也有潜在的作用。
The possible molecular basis for the previously described antagonistic interactions between adenosine A(1) receptors (A(1)R) and dopamine D-1 receptors (D1R) in the brain have been studied in mouse fibroblast Ltk(-) cells cotransfected with human A(1)R and D1R cDNAs or with human A(1)R and dopamine D-2 receptor (long-form) (D2R) cDNAs and in cortical neurons in culture. A(1)R and D1R, but not A(1)R and D2R, were found to coimmunoprecipitate in cotransfected fibroblasts. This selective A(1)R/D1R heteromerization disappeared after pretreatment with the D1R agonist, but not after combined pretreatment with D1R and A(1)R agonists. A high degree of A(1)R and D1R colocalization, demonstrated in double immunofluorescence experiments with confocal laser microscopy, was found in both cotransfected fibroblast cells and cortical neurons in culture. On the other hand, a low degree of A(1)R and D2R colocalization was observed in cotransfected fibroblasts. Pretreatment with the A(1)R agonist caused coclustering (coaggregation) of A(1)R and D1R. which was blocked by combined pretreatment with the D1R and A(1)R agonists in both fibroblast cells and in cortical neurons in culture. Combined pretreatment with D1R and A(1)R agonists, but not with either one alone, substantially reduced the D1R agonist-induced accumulation of cAMP. The A(1)R/D1R heteromerization may be one molecular basis for the demonstrated antagonistic modulation of A(1)R of D1R receptor signaling in the brain. The persistence of A(1)R/D1R heteromerization seems to be essential for the blockade of A(1)R agonist-induced A(1)R/D1R coclustering and for the desensitization of the D1R agonist-induced cAMP accumulation seen on combined pretreatment with D1R and A(1)R agonists, which indicates a potential role of A(1)R/D1R heteromers also in desensitization mechanisms and receptor trafficking.