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Physiological Cytosolic Ca2+ Transients Evoke Concurrent Mitochondiral Depolarizations
Leslie M. Loew, Walter Carrington, Richard A. Tuft and Fredric S. Fay
Proceedings of the National Academy of Sciences of the United States of America
Vol. 91, No. 26 (Dec. 20, 1994), pp. 12579-12583
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/2366385
Page Count: 5
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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.
Proceedings of the National Academy of Sciences of the United States of America © 1994 National Academy of Sciences