Rizzuto R, Brini M, Murgia M, Pozzan T
Department of Biomedical Sciences, University of Padova, Italy.
Science. 1993 Oct 29;262(5134):744-7. doi: 10.1126/science.8235595.
Microdomains of high intracellular calcium ion concentration, [Ca2+]i, have been hypothesized to occur in living cells exposed to stimuli that generate inositol 1,4,5-trisphosphate (IP3). Mitochondrially targeted recombinant aequorin was used to show that IP3-induced Ca2+ mobilization from intracellular stores caused increases of mitochondrial Ca2+ concentration, [Ca2+]m, the speed and amplitude of which are not accounted for by the relatively small increases in mean [Ca2+]i. A similar response was obtained by the addition of IP3 to permeabilized cells but not by perfusion of cells with Ca2+ at concentrations similar to those measured in intact cells. It is concluded that in vivo, domains of high [Ca2+]i are transiently generated close to IP3-gated channels and sensed by nearby mitochondria; this may provide an efficient mechanism for optimizing mitochondrial activity upon cell stimulation.
细胞内钙离子浓度（[Ca2+]i）较高的微区已被推测存在于暴露于能产生肌醇1,4,5-三磷酸（IP3）的刺激物的活细胞中。使用线粒体靶向重组水母发光蛋白来表明，IP3诱导的细胞内钙库Ca2+动员导致线粒体钙浓度（[Ca2+]m）增加，其速度和幅度无法用平均[Ca2+]i相对较小的增加来解释。通过向透化细胞中添加IP3可获得类似的反应，但用与完整细胞中测量浓度相似的Ca2+灌注细胞则不会。得出的结论是，在体内，高[Ca2+]i微区在靠近IP3门控通道处短暂产生，并被附近的线粒体感知；这可能为细胞受到刺激时优化线粒体活性提供一种有效机制。
