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首页> 外文期刊>Cell Calcium: The International Interdisciplinary Forum for Research on Calcium >The permeability transition pore as a Ca 2+ release channel: New answers to an old question
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The permeability transition pore as a Ca 2+ release channel: New answers to an old question

机译：作为Ca 2+释放通道的渗透性过渡孔：一个老问题的新答案

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摘要

Mitochondria possess a sophisticated array of Ca 2+ transport systems reflecting their key role in physiological Ca 2+ homeostasis. With the exception of most yeast strains, energized organelles are endowed with a very fast and efficient mechanism for Ca 2+ uptake, the ruthenium red (RR)-sensitive mitochondrial Ca 2+ uniporter (MCU); and one main mechanism for Ca 2+ release, the RR-insensitive 3Na +-Ca 2+ antiporter. An additional mechanism for Ca 2+ release is provided by a Na + and RR-insensitive release mechanism, the putative 3H +-Ca 2+ antiporter. A potential kinetic imbalance is present, however, because the V max of the MCU is of the order of 1400nmol Ca 2+mg -1 proteinmin -1 while the combined V max of the efflux pathways is about 20nmol Ca 2+mg -1 proteinmin -1. This arrangement exposes mitochondria to the hazards of Ca 2+ overload when the rate of Ca 2+ uptake exceeds that of the combined efflux pathways, e.g. for sharp increases of cytosolic [Ca 2+]. In this short review we discuss the hypothesis that transient opening of the Ca 2+-dependent permeability transition pore may provide mitocondria with a fast Ca 2+ release channel preventing Ca 2+ overload. We also address the relevance of a mitochondrial Ca 2+ release channel recently discovered in Drosophila melanogaster, which possesses intermediate features between the permeability transition pore of yeast and mammals.
机译：线粒体具有复杂的Ca 2+转运系统，反映了它们在生理Ca 2+体内平衡中的关键作用。除大多数酵母菌株外，赋能的细胞器具有非常快速有效的Ca 2+吸收机制，即对钌红（RR）敏感的线粒体Ca 2+单向转运蛋白（MCU）。 Ca 2+释放的一种主要机制是对RR不敏感的3Na + -Ca 2+反转运蛋白。 Na +和RR不敏感的释放机制提供了Ca 2+释放的另一种机制，即3H + -Ca 2+反向转运蛋白。但是，存在潜在的动力学失衡，因为MCU的V max约为1400nmol Ca 2 + mg -1 Proteinmin -1，而外排途径的总V max约为20nmol Ca 2 + mg -1 Proteinmin -1。当Ca 2+的摄取速率超过合并的外排途径的速率时，这种安排使线粒体暴露于Ca 2+超载的危险。胞质[Ca 2+]急剧增加。在这篇简短的综述中，我们讨论了Ca 2+依赖性渗透性过渡孔的瞬时打开可能为线粒体提供防止Ca 2+超载的快速Ca 2+释放通道的假说。我们还解决了最近在果蝇中发现的线粒体Ca 2+释放通道的相关性，该通道在酵母和哺乳动物的通透性转换孔之间具有中间特征。

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