Potassium uptake by guard cells represents part of the osmotic motor which drives stomatal opening, Patch-clamp measurements have identified inward rectifying K+ channels capable of mediating K+ uptake in guard cells and various other plant cell types, Here we report the molecular cloning and characterization of a voltage-dependent K+ channel (KST1) from potato (Solanum tuberosum L.) guard cells. In situ hybridization shows expression of kst1 in guard cells. Two electrode voltage-clamp and patch-clamp studies of the gene product after cRNA injection into Xenopus oocytes identified KST1 as a slowly activating, voltage-dependent, inward rectifying K+ channel. The single channel current voltage curve was linear in the range -160 to +20 mV, with a deduced single channel conductance of 7 pS in symmetrical 100 mM K+. This channel type, modulated by pH changes within the physiological range, required ATP for activation. In line with the properties of a K+-selective channel, KST1 was permeable to K+, Rb+ and NH4+ and excluded Na+ and Li+. Cs+ at submillimolar concentrations blocked the channel in a voltage-dependent manner. Related studies on potato guard cell protoplasts confirmed the biophysical characteristics of the kst1 gene product (KST1) in the heterologous expression system. Therefore, KST1 represents a major K+ uptake channel in potato guard cells.
%0 Journal Article
%1 RN1265
%A Mullerrober, B.
%A Ellenberg, J.
%A Provart, N.
%A Willmitzer, L.
%A Busch, H.
%A Becker, D.
%A Dietrich, P.
%A Hoth, S.
%A Hedrich, R.
%D 1995
%J Embo Journal
%K cells guard myOwn
%N 11
%P 2409-2416
%R DOI 10.1002/j.1460-2075.1995.tb07238.x
%T Cloning and Electrophysiological Analysis of Kst1, an Inward Rectifying K+ Channel Expressed in Potato Guard-Cells
%U /brokenurl#<Go to ISI>://WOS:A1995RC66400002
%V 14
%X Potassium uptake by guard cells represents part of the osmotic motor which drives stomatal opening, Patch-clamp measurements have identified inward rectifying K+ channels capable of mediating K+ uptake in guard cells and various other plant cell types, Here we report the molecular cloning and characterization of a voltage-dependent K+ channel (KST1) from potato (Solanum tuberosum L.) guard cells. In situ hybridization shows expression of kst1 in guard cells. Two electrode voltage-clamp and patch-clamp studies of the gene product after cRNA injection into Xenopus oocytes identified KST1 as a slowly activating, voltage-dependent, inward rectifying K+ channel. The single channel current voltage curve was linear in the range -160 to +20 mV, with a deduced single channel conductance of 7 pS in symmetrical 100 mM K+. This channel type, modulated by pH changes within the physiological range, required ATP for activation. In line with the properties of a K+-selective channel, KST1 was permeable to K+, Rb+ and NH4+ and excluded Na+ and Li+. Cs+ at submillimolar concentrations blocked the channel in a voltage-dependent manner. Related studies on potato guard cell protoplasts confirmed the biophysical characteristics of the kst1 gene product (KST1) in the heterologous expression system. Therefore, KST1 represents a major K+ uptake channel in potato guard cells.
@article{RN1265,
abstract = {Potassium uptake by guard cells represents part of the osmotic motor which drives stomatal opening, Patch-clamp measurements have identified inward rectifying K+ channels capable of mediating K+ uptake in guard cells and various other plant cell types, Here we report the molecular cloning and characterization of a voltage-dependent K+ channel (KST1) from potato (Solanum tuberosum L.) guard cells. In situ hybridization shows expression of kst1 in guard cells. Two electrode voltage-clamp and patch-clamp studies of the gene product after cRNA injection into Xenopus oocytes identified KST1 as a slowly activating, voltage-dependent, inward rectifying K+ channel. The single channel current voltage curve was linear in the range -160 to +20 mV, with a deduced single channel conductance of 7 pS in symmetrical 100 mM K+. This channel type, modulated by pH changes within the physiological range, required ATP for activation. In line with the properties of a K+-selective channel, KST1 was permeable to K+, Rb+ and NH4+ and excluded Na+ and Li+. Cs+ at submillimolar concentrations blocked the channel in a voltage-dependent manner. Related studies on potato guard cell protoplasts confirmed the biophysical characteristics of the kst1 gene product (KST1) in the heterologous expression system. Therefore, KST1 represents a major K+ uptake channel in potato guard cells.},
added-at = {2024-02-14T14:38:32.000+0100},
author = {Mullerrober, B. and Ellenberg, J. and Provart, N. and Willmitzer, L. and Busch, H. and Becker, D. and Dietrich, P. and Hoth, S. and Hedrich, R.},
biburl = {https://www.bibsonomy.org/bibtex/2b61a383d59bb775339f642338f950f10/rainerhedrich_2},
doi = {DOI 10.1002/j.1460-2075.1995.tb07238.x},
interhash = {393f4164663bdd4bb8bfdae9a9cf69da},
intrahash = {b61a383d59bb775339f642338f950f10},
issn = {0261-4189},
journal = {Embo Journal},
keywords = {cells guard myOwn},
note = {Rc664
Times Cited:181
Cited References Count:36},
number = 11,
pages = {2409-2416},
timestamp = {2024-02-14T14:38:32.000+0100},
title = {Cloning and Electrophysiological Analysis of Kst1, an Inward Rectifying K+ Channel Expressed in Potato Guard-Cells},
type = {Journal Article},
url = {/brokenurl#<Go to ISI>://WOS:A1995RC66400002},
volume = 14,
year = 1995
}