Loew L M, Carrington W, Tuft R A, Fay F S
Department of Physiology, University of Connecticut Health Center, Farmington 06030.
Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12579-83. doi: 10.1073/pnas.91.26.12579.
Calcium, a ubiquitous second messenger, stimulates the activity of several mitochondrial dehydrogenases. This has led to the suggestion that the same messenger that signals cell activation could also activate mitochondrial electron/proton transport, thereby meeting demands for increased cellular energy. To test this in live cells, quantitative three-dimensional microscopy and ratio imaging were used to measure membrane potential of individual mitochondria and cytosolic calcium distribution. Mitochondria reversibly depolarized as cytosolic calcium rose and then fell following physiological stimulation. Thus, the dominant response of the mitochondrion to a rise in cytosolic [Ca2+] is to draw on the electrochemical potential, possibly to accelerate processes directly involved in ATP synthesis and calcium homeostasis.
钙作为一种普遍存在的第二信使，可刺激多种线粒体脱氢酶的活性。这使人提出这样的推测，即这个信号细胞激活的信使同样也能激活线粒体电子/质子转运，从而满足细胞能量增加的需求。为了在活细胞中对此进行测试，采用了定量三维显微镜和比率成像技术来测量单个线粒体的膜电位以及胞质钙分布。随着胞质钙升高，线粒体发生可逆性去极化，随后在生理刺激后又恢复。因此，线粒体对胞质[Ca2+]升高的主要反应是利用电化学势，可能是为了加速直接参与ATP合成和钙稳态的过程。
