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Ryanodine Receptor as Redox Monitor

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Science's STKE  21 Nov 2000:
Vol. 2000, Issue 59, pp. tw1
DOI: 10.1126/stke.2000.59.tw1

Ryanodine receptors mediate release of calcium from intracellular stores in the endoplasmic or sarcoplasmic reticulum. In the stores, the ratio of the concentration of glutathione to that of glutathione disulfide [GSH]:[GSSG] is about 3:1, whereas in the cytoplasm, the ratio is more like 30:1. Feng et al. explored whether this transmembrane redox potential might influence calcium flux through the ryanodine receptor. Their results show that vesicles derived from the sarcoplasmic reticulum regulate their [GSH]:[GSSG] to be approximately 3:1, even when the cytoplasmic redox potential was varied. Furthermore, small changes in redox potential altered calcium conductance by the ryanodine receptors. Single-channel recordings in bilayer lipid membranes showed that the open probability of the channel increased as the redox potential across the membrane increased. The redox potential appears to be sensed by the thiol groups in the ryanodine receptor complex. The authors propose that ryanodine receptors may physiologically couple alterations in calcium release to localized changes in redox potential.

Feng, W., Liu, G., Allen, P.D., and Pessah, I.N. (2000) Transmembrane redox sensor of ryanodine receptor complex. J. Biol. Chem. 275: 35902-35907. [Abstract] [Full Text]

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