Mitochondrial participation in the intracellular Ca2+ network.
Mitochondrial participation in the intracellular Ca2+ network.
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线粒体参与细胞内Ca2+网络。
DOI：
10.1083/jcb.136.4.833
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发表时间：
1997-02-24
期刊：
影响因子：
--
通讯作者：
Hille B
中科院分区：
文献类型：
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作者：
Babcock DF;Herrington J;Goodwin PC;Park YB;Hille B
钙可以激活线粒体代谢，线粒体钙摄取和排出调节胞浆内游离钙离子(CaC)的可能性重新引起人们的关注。我们使用全细胞膜片钳和穿孔膜片钳方法，结合快速局部灌流，将探针和抑制剂引入大鼠嗜铬细胞，以激发钙内流，并监测报告近表面[钙]的钙激活电流。我们发现，从CAC升高中快速恢复需要线粒体钙单转运体和线粒体的能量，线粒体能量通过它来驱动钙的摄取。应用成像和单细胞光度方法，我们发现探针Rhod-2选择性地定位于线粒体，并利用其反应来定量线粒体游离[Ca~(2+)](CaM)。显示的静息CaM为100-200 nm，与探针Indo-1和钙绿报告的静息CaC或其在细胞质中的葡聚糖结合物相似。在高时间分辨率下对CaM和CAC的同时监测表明，虽然CaM的增加幅度小于CAC，但线粒体对钙离子的截留速度快，容量大。我们发现，线粒体的钙摄取限制了钙离子的升高，并且是钙离子进入或网状库动员所产生的钙离子漂移的快速衰减的基础。我们还发现，线粒体随后的钙离子输出，即CaM的下降，延长了CAC的完全恢复时间，而通过抑制线粒体Na+/Ca~(2+)交换而抑制Ca~(2+)的输出，可逆地加速了CAC的最终恢复。我们认为线粒体是细胞内钙信号的积极参与者，其独特的作用取决于其快速积累和释放大量钙离子的能力。
Calcium can activate mitochondrial metabolism, and the possibility that mitochondrial Ca2+ uptake and extrusion modulate free cytosolic [Ca2+] (Cac) now has renewed interest. We use whole-cell and perforated patch clamp methods together with rapid local perfusion to introduce probes and inhibitors to rat chromaffin cells, to evoke Ca2+ entry, and to monitor Ca2+-activated currents that report near-surface [Ca2+]. We show that rapid recovery from elevations of Cac requires both the mitochondrial Ca2+ uniporter and the mitochondrial energization that drives Ca2+ uptake through it. Applying imaging and single-cell photometric methods, we find that the probe rhod-2 selectively localizes to mitochondria and uses its responses to quantify mitochondrial free [Ca2+] (Cam). The indicated resting Cam of 100–200 nM is similar to the resting Cac reported by the probes indo-1 and Calcium Green, or its dextran conjugate in the cytoplasm. Simultaneous monitoring of Cam and Cac at high temporal resolution shows that, although Cam increases less than Cac, mitochondrial sequestration of Ca2+ is fast and has high capacity. We find that mitochondrial Ca2+ uptake limits the rise and underlies the rapid decay of Cac excursions produced by Ca2+ entry or by mobilization of reticular stores. We also find that subsequent export of Ca2+ from mitochondria, seen as declining Cam, prolongs complete Cac recovery and that suppressing export of Ca2+, by inhibition of the mitochondrial Na+/ Ca2+ exchanger, reversibly hastens final recovery of Cac. We conclude that mitochondria are active participants in cellular Ca2+ signaling, whose unique role is determined by their ability to rapidly accumulate and then release large quantities of Ca2+.