MtCLIC is up-regulated and maintains a mitochondrial membrane potential in mtDNA-depleted L929 cells
MtCLIC is up-regulated and maintains a mitochondrial membrane potential in mtDNA-depleted L929 cells
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DOI：
10.1096/fj.03-0075fje
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发表时间：
2003-09-01
期刊：
影响因子：
4.8
通讯作者：
Raes, M
中科院分区：
文献类型：
--
作者：
Arnould, T;Mercy, L;Raes, M
为了解释为什么线粒体DNA（mtDNA）耗尽或rho 0细胞在没有呼吸的情况下仍然保持线粒体膜电位（Deltapsim），已经提出了几个假设。主要的和公认的一个涉及的作用，结合F1-ATP酶活性的ANT的逆转。然而，其他假定的生电通道的存在已被推测。在这里，使用mRNA差异显示逆转录酶-聚合酶链反应L929 mtDNA耗尽的细胞，我们确定mtCLIC作为一个差异表达的基因在细胞中剥夺线粒体ATP的生产。线粒体氯离子通道（Mitochondrial chloride intracellular channel，mtCLIC）是近年来发现的一个氯离子通道家族，在线粒体DNA缺失和rho 0细胞中表达上调。我们发现它的表达依赖于CREB和p53，对钙和肿瘤坏死因子α敏感。有趣的是，上调或下调mtCLIC蛋白表达改变Deltapsim，而氯离子通道抑制剂NPPB减少了Deltapsim在mtDNA耗尽的L929细胞中，用荧光探针罗丹明123测量。最后，我们证明了从mtDNA耗尽的细胞中纯化的线粒体以NPPB敏感的方式掺入比亲本线粒体更多的氯。这些发现表明，mtCLIC可能参与线粒体DNA耗尽细胞的线粒体膜电位生成，这是防止细胞凋亡和驱动蛋白质连续输入线粒体所需的特征。
To explain why mitochondrial DNA ( mtDNA)-depleted or rho0 cells still keep a mitochondrial membrane potential (Deltapsim) in the absence of respiration, several hypotheses have been proposed. The principal and well accepted one involves a reverse of action for ANT combined to F1-ATPase activity. However, the existence of other putative electrogenic channels has been speculated. Here, using mRNA differential display reverse transcriptase-polymerase chain reaction on L929 mtDNA-depleted cells, we identified mtCLIC as a differentially expressed gene in cells deprived from mitochondrial ATP production. Mitochondrial chloride intracellular channel ( mtCLIC), a member of a recently discovered and expanding family of chloride intracellular channels, is up-regulated in mtDNA-depleted and rho0 cells. We showed that its expression is dependent on CREB and p53 and is sensitive to calcium and tumor necrosis factor alpha. Interestingly, up- or down-regulation of mtCLIC protein expression changes Deltapsim whereas the chloride channel inhibitor NPPB reduces the Deltapsim in mtDNA-depleted L929 cells, measured with the fluorescent probe rhodamine 123. Finally, we demonstrated that purified mitochondria from mtDNA-depleted cells incorporate, in a NPPB-sensitive manner, more (36)chloride than parental mitochondria. These findings suggest that mtCLIC could be involved in mitochondrial membrane potential generation in mtDNA-depleted cells, a feature required to prevent apoptosis and to drive continous protein import into mitochondria.