The role of calcium entry through the mitochondrial uniporter in regulating cardiac metabolism and physiology

钙进入线粒体在调节生物能量方面是至关重要的 能力和调节细胞死亡阈值。近五十年来，线粒体被认为是 在线粒体内膜上有一个选择性的钙选择孔。进入 钙通过这个孔，通常被称为钙单向转运体，被认为是必不可少的， 通过增强多个钙敏感线粒体的活性来促进ATP的产生 基质酶因此，线粒体钙的这种增加允许快速，但 在能量需求增加的条件下，调节线粒体ATP的增加。而 在这些条件下，钙的进入似乎是有益的， 过多的钙离子进入会触发线粒体细胞死亡程序， 线粒体通透性转换孔（mPTP）的开放。这种情况似乎是 特别是与在缺血-再灌注损伤情况下发生的组织损伤相关。而 大量的电生理学、生物物理学和生理学数据存在于 线粒体内膜钙孔，其分子身份仍然难以捉摸超过50年 年在过去五年中，这种情况发生了明显变化， 线粒体内钙单向转运体复合物（MCUC）的组分鉴定 目前已知至少由四种蛋白质组成。这些组件包括孔- 形成蛋白MCU，其表观膜支架EMRE和两个钙敏感 调节器MICU 1和MICU 2。MCUC的分子特性为 创建其中复合物的一个或多个组分已被删除的小鼠模型。 这反过来又允许更详细和精确地分析 线粒体钙在调节生物能量学和细胞死亡中的作用。在此，我们建议 分析MCUC在基础和应激诱导的心血管生理学中的作用。我们 特别强调的是MCUC在缺血/再灌注损伤、代谢、 和衰老。我们相信，这一分析将增加我们对这两个问题的基本理解。 线粒体生物学和心脏生理学，并可能为新的治疗方法铺平道路 针对从再灌注损伤到年龄的各种情况的策略， 心脏功能的依赖性下降。

The entry of calcium into the mitochondria is fundamentally important in regulating bioenergetic capacity and modulating cell death thresholds. For nearly fifty years, mitochondria were known to have a selective calcium-selective pore in the inner mitochondrial membrane. Entry of calcium through this pore, often termed the calcium uniporter, was believed to be essential in boosting ATP production by augmenting the activity of multiple calcium-sensitive mitochondrial matrix enzymes. This increase in mitochondrial calcium therefore allowed for a rapid but regulated increase in mitochondrial ATP under conditions of increased energetic demand. While under these conditions, the entry of calcium appears beneficial, additional evidence suggested that excessive calcium entry triggers a mitochondrial cell death program characterized by opening of the mitochondrial permeability transition pore (mPTP). Such situations appear to be particularly relevant to tissue injury occurring in the setting of ischemia-reperfusion injury. While considerable electrophysiological, biophysical and physiological data existed on the mitochondrial inner membrane calcium pore, its molecular identity remained elusive for over fifty years. That situation has demonstrably changed in the last five years with the rapid identification of the components of the inner mitochondrial calcium uniporter complex (MCUC) now known to be composed of at least four proteins. These components include the pore- forming protein MCU, its apparent membrane scaffold EMRE and two calcium-sensitive regulators MICU1 and MICU2. The molecular identity of the MCUC paved the way for the creation of mouse models in which one or more component of the complex has been deleted. This, in turn, allows for a more detailed and precise analysis of the physiological role of mitochondrial calcium in regulating both bioenergetics and cell death. Here, we propose to analyze the role of the MCUC in basal and stress-induced cardiovascular physiology. Our particular emphasis will be on the role of the MCUC in ischemia/reperfusion injury, metabolism and aging. This analysis, we believe, will increase our fundamental understanding of both mitochondrial biology and cardiac physiology and potentially pave the way for new treatment strategies targeting a diverse array of conditions ranging from reperfusion injury to the age- dependent decline in cardiac function.