Molecular reorganization of Cx43, Zo-1 and Src complexes during the endocytosis of gap junction plaques in response to a non-genomic carcinogen
Molecular reorganization of Cx43, Zo-1 and Src complexes during the endocytosis of gap junction plaques in response to a non-genomic carcinogen
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DOI：
10.1242/jcs.033373
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发表时间：
2008-12-15
影响因子：
4
通讯作者：
Pointis, Georges
中科院分区：
文献类型：
--
作者：
Gilleron, Jerome;Fiorini, Celine;Pointis, Georges
差距连接蛋白43（Cx43）表现出动态运输，其在大多数肿瘤细胞中改变并且响应于致癌物暴露。已知许多连接蛋白（Cx）结合蛋白参与间隙连接的内吞内化。在这里，我们分析了离散的分子之间的相互作用，发生在Src，ZO-1和Cx43在Cx43的内在化响应于非基因组致癌物γ-六氯环己烷（HCH）。在暴露于致癌物的Cx43-GFP转染的42 GPA 9 Sertoli细胞中，Cx43间隙连接斑块的内化显著加速。六氯环己烷诱导Src的快速招聘到质膜，激活Src在3分钟内和有效的抑制间隙连接耦合，但没有影响的Src抑制剂PP 2的存在。免疫沉淀实验表明，六氯环己烷增加Cx43-Src的相互作用，同时减少Cx43-ZO-1协会。ZO-1在未处理的细胞中的差距连接斑块的两侧都被检测到，但在六氯环己烷诱导的内化过程中似乎主要定位于一侧。ZO-1与Cx43的解离似乎特异性地发生在Src被募集的斑块一侧。这些研究结果提供了机制的证据，Cx43间隙连接斑块的内化可能被启动，这表明Src介导的ZO-1从斑块的一侧解离启动间隙连接的内吞内化，并且这一过程在暴露于六氯环己烷时被放大。
The gap junction protein connexin 43 (Cx43) exhibits dynamic trafficking that is altered in most tumor cells and in response to carcinogen exposure. A number of connexin (Cx)-binding proteins are known to be involved in endocytic internalization of gap junctions. Here, we analyzed the discrete molecular interactions that occur between Src, ZO-1 and Cx43 during Cx43 internalization in response to the non-genomic carcinogen gamma-hexachlorocyclohexane (HCH). Internalization of the Cx43 gap junction plaque was significantly accelerated in Cx43-GFP transfected 42GPA9 Sertoli cells that were exposed to the carcinogen. HCH induced the rapid recruitment of Src to the plasma membrane, activation of Src within 3 minutes and the efficient inhibition of gap junctional coupling, but had no effect in the presence of the Src inhibitor PP2. Immunoprecipitation experiments demonstrated that HCH increased Cx43-Src interaction and concomitantly decreased Cx43-ZO-1 association. ZO-1 was detected on both sides of the gap junction plaques in untreated cells, but appeared to be mainly localized on one side during HCH-induced internalization. The dissociation of ZO-1 from Cx43 appears to occur specifically on the side of the plaque to which Src was recruited. These findings provide mechanistic evidence by which internalization of the Cx43 gap junction plaque might be initiated, suggesting that Src-mediated dissociation of ZO-1 from one side of the plaque initiates endocytic internalization of gap junctions and that this process is amplified in response to exposure to HCH.