Recombinant expression of the Ca2+-sensitive aspartate/glutamate carrier increases mitochondrial ATP production in agonist-stimulated chinese hamster ovary cells
Recombinant expression of the Ca2+-sensitive aspartate/glutamate carrier increases mitochondrial ATP production in agonist-stimulated chinese hamster ovary cells
复制标题
DOI：
10.1074/jbc.m304988200
复制
发表时间：
2003-10-03
影响因子：
4.8
通讯作者：
Palmieri, F
中科院分区：
文献类型：
--
作者：
Lasorsa, FM;Pinton, P;Palmieri, F
到目前为止，线粒体基质的Ca 2+敏感性的磷酸酶是唯一已知的允许Ca 2+信号将质膜受体的活化与有氧代谢的刺激偶联的效应物。在这项研究中，我们展示了一种新的机制，基于Ca 2+敏感的代谢物载体的内膜。我们在中国仓鼠卵巢细胞中表达aralar 1和citrin，天冬氨酸/谷氨酸交换剂，在其序列中具有Ca 2+结合位点，并测量线粒体Ca 2+和ATP水平以及细胞溶质Ca 2+浓度与靶向重组探针。与Ca 2+动员激动剂的细胞刺激所引起的线粒体ATP水平的增加是显着更大的细胞表达arrhythmia和citrin（但不是截短的突变体缺乏Ca 2+结合位点）比对照细胞。相反，细胞质和线粒体Ca 2+信号是相同的控制细胞和细胞表达不同的aralar 1和柠檬酸变异体，从而排除了通过Ca 2 +-敏感的酶的间接影响。总之，这些数据表明，线粒体中的Ca 2+信号的解码取决于线粒体酶和载体的协调活性，因此，这可能代表了这个过程中的主要病理生理学兴趣的有用的药理学目标。
The Ca2+-sensitive dehydrogenases of the mitochondrial matrix are, so far, the only known effectors to allow Ca2+ signals to couple the activation of plasma membrane receptors to the stimulation of aerobic metabolism. In this study, we demonstrate a novel mechanism, based on Ca2+- sensitive metabolite carriers of the inner membrane. We expressed in Chinese hamster ovary cells aralar1 and citrin, aspartate/glutamate exchangers that have Ca2+- binding sites in their sequence, and measured mitochondrial Ca2+ and ATP levels as well as cytosolic Ca2+ concentration with targeted recombinant probes. The increase in mitochondrial ATP levels caused by cell stimulation with Ca2+- mobilizing agonists was markedly larger in cells expressing aralar and citrin ( but not truncated mutants lacking the Ca2+-binding site) than in control cells. Conversely, the cytosolic and the mitochondrial Ca2+ signals were the same in control cells and cells expressing the different aralar1 and citrin variants, thus ruling out an indirect effect through the Ca2+- sensitive dehydrogenases. Together, these data show that the decoding of Ca2+ signals in mitochondria depends on the coordinate activity of mitochondrial enzymes and carriers, which may thus represent useful pharmacological targets in this process of major pathophysiological interest.