Direct binding of activated c-Src to the β3-adrenergic receptor is required for MAP kinase activation
Direct binding of activated c-Src to the β3-adrenergic receptor is required for MAP kinase activation
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DOI：
10.1074/jbc.c000592200
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发表时间：
2000-12-08
影响因子：
4.8
通讯作者：
Collins, S
中科院分区：
文献类型：
--
作者：
Cao, WH;Luttrell, LM;Collins, S
β(2)-和β(3)-肾上腺素能受体(ARs)都能激活细胞外信号调节激酶(ERK)途径。我们先前的研究表明，c-Src是β(2)AR激活ERK所必需的，它是通过将Src同源3(SH3)结构域与接头蛋白β-arrestin1的富含脯氨酸的区域结合而被招募到激活的β(2)AR中的，尽管没有磷酸化和β-arrestin结合的位点，但P(3)AR激活ERK仍然需要c-Src。激动剂激活β(2)AR，而不是β(3)AR，导致绿色荧光蛋白标记的p-arrestin重新分布到质膜上。在P-arrestin缺失的COS-7细胞中，β-arrestin依赖的c-Src与β(2)AR共沉淀需要外源性p-arrestin，但在p-arrestin存在或不存在的情况下，激活的beta(3)AR共沉淀c-Src，ERK激活和Src与β(3)AR以激动剂依赖和百日咳毒素敏感的方式在脂肪细胞中共沉淀。蛋白质相互作用研究表明，β(3)AR通过细胞内第三环和羧基末端的富含脯氨酸基序(PXXP)直接与Src的SH3结构域相互作用。在表达这些PXXP基序的点突变的细胞中，Erk激活和Src共沉淀被取消。总之，这些数据描述了一种由G蛋白偶联受体激活ERK的新机制，在这种机制中，细胞内结构域直接招募c-Src。
Both beta (2)- and beta (3)-adrenergic receptors (ARs) are able to activate the extracellular signal-regulated kinase (ERK) pathway. We previously showed that c-Src is required for ERK activation by beta (2)AR and that it is recruited to activated beta (2)AR through binding of the Src homology 3 (SH3) domain to proline-rich regions of the adapter protein beta -arrestin1, Despite the absence of sites for phosphorylation and beta -arrestin binding, ERK activation by P(3)AR still requires c-Src. Agonist activation of beta (2)AR, but not beta (3)AR, led to redistribution of green fluorescent protein-tagged p-arrestin to the plasma membrane. In P-arrestin-deficient COS-7 cells, beta -affonist-dependent coprecipitation of c-Src with the beta (2)AR required exogenous p-arrestin, but activated beta (3)AR co-precipitated c-Src in the absence or presence of p-arrestin, ERK activation and Src co-precipitation with beta (3)AR also occurred in adipocytes in an agonist-dependent and pertussis toxin-sensitive manner. Protein interaction studies show that the beta (3)AR interacts directly with the SH3 domain of Src through proline-rich motifs (PXXP) in the third intracellular loop and the carboxyl terminus. ERK activation and Src co-precipitation were abolished in cells expressing point mutations in these PXXP motifs. Together, these data describe a novel mechanism of ERK activation by a G protein-coupled receptor in which the intracellular domains directly recruit c-Src.