Voltage-dependent inward-rectifying (Ki(in)) and outward-rectifying (K-out) K+ channels are capable of mediating K+ fluxes across the plasma membrane. Previous studies on guard cells or heterologously expressed K+ channels provided evidence for the requirement of ATP to maintain K+ channel activity. Here, the nucleotide and Mg2+ dependencies of time-dependent Ki(in) and K-out channels from maize subsidiary cells were examined, showing that MgATP as well as MgADP function as channel activators. In addition to K-out channels, these studies revealed the presence of another outward-rectifying channel type (MgC) in the plasma membrane that however gates in a nucleotide-independent manner. MgC represents a new channel type distinguished from K-out, channels by fast activation kinetics, inhibition by elevated intracellular Mg2+ concentration, permeability for K+ as well as for Na+ and insensitivity towards TEA(+). Similar observations made for guard cells from Zea mays and Vicia faba suggest a conserved regulation of channel-mediated K+ and Na+ transport in both cell types and species.
%0 Journal Article
%1 RN1163
%A Wolf, T.
%A Guinot, D. R.
%A Hedrich, R.
%A Dietrich, P.
%A Marten, I.
%D 2005
%J Plant and Cell Physiology
%K cell guard myOwn
%N 10
%P 1682-1689
%R 10.1093/pcp/pci184
%T Nucleotides and Mg
ions differentially regulate K
channels and non-selective cation channels present in cells forming the stomatal complex
%U /brokenurl#<Go to ISI>://WOS:000233084000010
%V 46
%X Voltage-dependent inward-rectifying (Ki(in)) and outward-rectifying (K-out) K+ channels are capable of mediating K+ fluxes across the plasma membrane. Previous studies on guard cells or heterologously expressed K+ channels provided evidence for the requirement of ATP to maintain K+ channel activity. Here, the nucleotide and Mg2+ dependencies of time-dependent Ki(in) and K-out channels from maize subsidiary cells were examined, showing that MgATP as well as MgADP function as channel activators. In addition to K-out channels, these studies revealed the presence of another outward-rectifying channel type (MgC) in the plasma membrane that however gates in a nucleotide-independent manner. MgC represents a new channel type distinguished from K-out, channels by fast activation kinetics, inhibition by elevated intracellular Mg2+ concentration, permeability for K+ as well as for Na+ and insensitivity towards TEA(+). Similar observations made for guard cells from Zea mays and Vicia faba suggest a conserved regulation of channel-mediated K+ and Na+ transport in both cell types and species.
@article{RN1163,
abstract = {Voltage-dependent inward-rectifying (Ki(in)) and outward-rectifying (K-out) K+ channels are capable of mediating K+ fluxes across the plasma membrane. Previous studies on guard cells or heterologously expressed K+ channels provided evidence for the requirement of ATP to maintain K+ channel activity. Here, the nucleotide and Mg2+ dependencies of time-dependent Ki(in) and K-out channels from maize subsidiary cells were examined, showing that MgATP as well as MgADP function as channel activators. In addition to K-out channels, these studies revealed the presence of another outward-rectifying channel type (MgC) in the plasma membrane that however gates in a nucleotide-independent manner. MgC represents a new channel type distinguished from K-out, channels by fast activation kinetics, inhibition by elevated intracellular Mg2+ concentration, permeability for K+ as well as for Na+ and insensitivity towards TEA(+). Similar observations made for guard cells from Zea mays and Vicia faba suggest a conserved regulation of channel-mediated K+ and Na+ transport in both cell types and species.},
added-at = {2024-02-14T14:38:32.000+0100},
author = {Wolf, T. and Guinot, D. R. and Hedrich, R. and Dietrich, P. and Marten, I.},
biburl = {https://www.bibsonomy.org/bibtex/21dc102dd0fc43dc3191d5736a93f44aa/rainerhedrich_2},
doi = {10.1093/pcp/pci184},
interhash = {e8cfce78431fb310ff533f400202e4dc},
intrahash = {1dc102dd0fc43dc3191d5736a93f44aa},
issn = {0032-0781},
journal = {Plant and Cell Physiology},
keywords = {cell guard myOwn},
note = {981jd
Times Cited:10
Cited References Count:38},
number = 10,
pages = {1682-1689},
timestamp = {2024-02-14T14:38:32.000+0100},
title = {Nucleotides and Mg
ions differentially regulate K
channels and non-selective cation channels present in cells forming the stomatal complex},
type = {Journal Article},
url = {/brokenurl#<Go to ISI>://WOS:000233084000010},
volume = 46,
year = 2005
}