Mitochondrial regulation of store-operated calcium signaling in T lymphocytes
Mitochondrial regulation of store-operated calcium signaling in T lymphocytes
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DOI：
10.1083/jcb.137.3.633
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发表时间：
1997-05-05
影响因子：
7.8
通讯作者：
Lewis, RS
中科院分区：
文献类型：
--
作者：
Hoth, M;Fanger, CM;Lewis, RS
线粒体在许多细胞中充当细胞内Ca 2+的有效缓冲器，但在调节Ca 2+信号的产生中更积极的作用尚未完全确立。我们已经调查了线粒体的能力，以调节存储操作或“容量”的钙离子进入Jurkat白血病T细胞和人T淋巴细胞使用荧光成像技术。用毒胡萝卜素（TG）耗尽ER Ca 2+储存激活T细胞中的Ca 2+释放激活的Ca 2+（CRAC）通道，并且随后的Ca 2+流入加载TG不敏感的细胞内储存，根据几个标准，该细胞内储存似乎是线粒体。这种存储的加载被羰基氰化物间氯苯腙或抗霉素Al +寡霉素阻止，这些药物已知通过耗散线粒体膜电位来抑制线粒体Ca 2+输入。相反，细胞内Nat耗竭，抑制Nat依赖性的Ca 2+从线粒体输出，增强存储加载。此外，我们发现rhod-2标记T细胞中的线粒体，并且它报告了与其在TG不敏感存储中的定位一致的Ca 2+水平的变化。由线粒体存储的Ca 2+摄取是敏感的（阈值为10分钟。在这些条件下，在单细胞中的Ca 2+流入率经历了从高流入到低流入状态的突然转变。这些结果表明，线粒体不仅缓冲通过钙库操作的Ca 2+通道进入T细胞的Ca 2+，而且在调节容量性Ca 2+进入速率中发挥积极作用。
Mitochondria act as potent buffers of intracellular Ca2+ in many cells, but a more active role in modulating the generation of Ca2+ signals is not well established. We have investigated the ability of mitochondria to modulate store-operated or ''capacitative'' Ca2+ entry in Jurkat leukemic T cells and human T lymphocytes using fluorescence imaging techniques. Depletion of the ER Ca2+ store with thapsigargin (TG) activates Ca2+ release-activated Ca2+ (CRAC) channels in T cells, and the ensuing influx of Ca2+ loads a TG-insensitive intracellular store that by several criteria appears to be mitochondria. Loading of this store is prevented by carbonyl cyanide m-chlorophenylhydrazone or by antimycin Al + oligomycin, agents that are known to inhibit mitochondrial Ca2+ import by dissipating the mitochondrial membrane potential. Conversely, intracellular Nat depletion, which inhibits Nat-dependent Ca2+ export from mitochondria, enhances store loading. In addition, we find that rhod-2 labels mitochondria in T cells, and it reports changes in Ca2+ levels that are consistent with its localization in the TG-insensitive store. Ca2+ uptake by the mitochondrial store is sensitive (threshold is 10 min. Under these conditions, the rate of Ca2+ influx in single cells undergoes abrupt transitions from a high influx to a low influx state. These results demonstrate that mitochondria not only buffer the Ca2+ that enters T cells via store-operated Ca2+ channels, but also play an active role in modulating the rate of capacitative Ca2+ entry.