P>Rapid stomatal closure is driven by the activation of S-type anion channels in the plasma membrane of guard cells. This response has been linked to Ca2+ signalling, but the impact of transient Ca2+ signals on S-type anion channel activity remains unknown. In this study, transient elevation of the cytosolic Ca2+ level was provoked by voltage steps in guard cells of intact Nicotiana tabacum plants. Changes in the activity of S-type anion channels were monitored using intracellular triple-barrelled micro-electrodes. In cells kept at a holding potential of -100 mV, voltage steps to -180 mV triggered elevation of the cytosolic free Ca2+ concentration. The increase in the cytosolic Ca2+ level was accompanied by activation of S-type anion channels. Guard cell anion channels were activated by Ca2+ with a half maximum concentration of 515 nm (SE = 235) and a mean saturation value of -349 pA (SE = 107) at -100 mV. Ca2+ signals could also be evoked by prolonged (100 sec) depolarization of the plasma membrane to 0 mV. Upon returning to -100 mV, a transient increase in the cytosolic Ca2+ level was observed, activating S-type channels without measurable delay. These data show that cytosolic Ca2+ elevation can activate S-type anion channels in intact guard cells through a fast signalling pathway. Furthermore, prolonged depolarization to 0 mV alters the activity of Ca2+ transport proteins, resulting in an overshoot of the cytosolic Ca2+ level after returning the membrane potential to -100 mV.
%0 Journal Article
%1 RN1114
%A Stange, A.
%A Hedrich, R.
%A Roelfsema, M. R. G.
%D 2010
%J Plant Journal
%K anion channel myOwn s-type
%N 2
%P 265-276
%R 10.1111/j.1365-313X.2010.04141.x
%T Ca2+-dependent activation of guard cell anion channels, triggered by hyperpolarization, is promoted by prolonged depolarization
%U /brokenurl#<Go to ISI>://WOS:000276496300008
%V 62
%X P>Rapid stomatal closure is driven by the activation of S-type anion channels in the plasma membrane of guard cells. This response has been linked to Ca2+ signalling, but the impact of transient Ca2+ signals on S-type anion channel activity remains unknown. In this study, transient elevation of the cytosolic Ca2+ level was provoked by voltage steps in guard cells of intact Nicotiana tabacum plants. Changes in the activity of S-type anion channels were monitored using intracellular triple-barrelled micro-electrodes. In cells kept at a holding potential of -100 mV, voltage steps to -180 mV triggered elevation of the cytosolic free Ca2+ concentration. The increase in the cytosolic Ca2+ level was accompanied by activation of S-type anion channels. Guard cell anion channels were activated by Ca2+ with a half maximum concentration of 515 nm (SE = 235) and a mean saturation value of -349 pA (SE = 107) at -100 mV. Ca2+ signals could also be evoked by prolonged (100 sec) depolarization of the plasma membrane to 0 mV. Upon returning to -100 mV, a transient increase in the cytosolic Ca2+ level was observed, activating S-type channels without measurable delay. These data show that cytosolic Ca2+ elevation can activate S-type anion channels in intact guard cells through a fast signalling pathway. Furthermore, prolonged depolarization to 0 mV alters the activity of Ca2+ transport proteins, resulting in an overshoot of the cytosolic Ca2+ level after returning the membrane potential to -100 mV.
@article{RN1114,
abstract = {P>Rapid stomatal closure is driven by the activation of S-type anion channels in the plasma membrane of guard cells. This response has been linked to Ca2+ signalling, but the impact of transient Ca2+ signals on S-type anion channel activity remains unknown. In this study, transient elevation of the cytosolic Ca2+ level was provoked by voltage steps in guard cells of intact Nicotiana tabacum plants. Changes in the activity of S-type anion channels were monitored using intracellular triple-barrelled micro-electrodes. In cells kept at a holding potential of -100 mV, voltage steps to -180 mV triggered elevation of the cytosolic free Ca2+ concentration. The increase in the cytosolic Ca2+ level was accompanied by activation of S-type anion channels. Guard cell anion channels were activated by Ca2+ with a half maximum concentration of 515 nm (SE = 235) and a mean saturation value of -349 pA (SE = 107) at -100 mV. Ca2+ signals could also be evoked by prolonged (100 sec) depolarization of the plasma membrane to 0 mV. Upon returning to -100 mV, a transient increase in the cytosolic Ca2+ level was observed, activating S-type channels without measurable delay. These data show that cytosolic Ca2+ elevation can activate S-type anion channels in intact guard cells through a fast signalling pathway. Furthermore, prolonged depolarization to 0 mV alters the activity of Ca2+ transport proteins, resulting in an overshoot of the cytosolic Ca2+ level after returning the membrane potential to -100 mV.},
added-at = {2024-02-14T14:38:32.000+0100},
author = {Stange, A. and Hedrich, R. and Roelfsema, M. R. G.},
biburl = {https://www.bibsonomy.org/bibtex/26add487c1237cacd4ad6ec6e034b0aed/rainerhedrich_2},
doi = {10.1111/j.1365-313X.2010.04141.x},
interhash = {3c454f62a8faa950e5822c68853350dc},
intrahash = {6add487c1237cacd4ad6ec6e034b0aed},
issn = {0960-7412},
journal = {Plant Journal},
keywords = {anion channel myOwn s-type},
note = {581bp
Times Cited:30
Cited References Count:66},
number = 2,
pages = {265-276},
timestamp = {2024-02-14T14:38:32.000+0100},
title = {Ca2+-dependent activation of guard cell anion channels, triggered by hyperpolarization, is promoted by prolonged depolarization},
type = {Journal Article},
url = {/brokenurl#<Go to ISI>://WOS:000276496300008},
volume = 62,
year = 2010
}