%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 }