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Mg(2+)-dependent inward rectification of ROMK1 potassium channels expressed in Xenopus oocytes.
Nichols CG
,
Ho K
,
Hebert S
.
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1. ROMK1 potassium channel currents were examined in Xenopus oocytes by two-microelectrode voltage-clamp and patch-clamp techniques following injection of oocytes with in vitro transcribed ROMK1 cRNA. Macroscopic currents recorded from intact cells rectified inwardly at positive potentials. 2. In inside-out membrane patches rectification is manifested as an apparent reduction of single channel current (at 500 Hz) in the presence of 0.1-10 mM Mg2+, without a decrease in the channel open probability. No inward rectification is observed when membrane patches are isolated into solutions containing potassium as the only internal inorganic cation. 3. Mg2+ block can be described by a simple one-site model for Mg2+ binding with K0 ([Mg2+] causing half-maximal block at 0 mV) of 16.7 mM and delta (the fraction of the membrane field sensed by the blocking Mg2+) of 0.35. 4. The voltage dependence of channel block by cytoplasmic Mg2+ was shifted approximately -50 mV by a reduction in extracellular [K+] from 140 to 0 mM, corresponding to a decrease of K0 to 4.4 mM. 5. At negative membrane potentials, ROMK1 channels exhibit a single subconducting state that is approximately 4/10 of the full conductance. The incidence of subconductance states is not appreciably enhanced in the presence of Mg2+.
Berry,
Correlated ion flux through parallel pores: application to channel subconductance states.
1993, Pubmed
Berry,
Correlated ion flux through parallel pores: application to channel subconductance states.
1993,
Pubmed
Boulter,
Molecular cloning and functional expression of glutamate receptor subunit genes.
1990,
Pubmed
,
Xenbase
Burnashev,
Control by asparagine residues of calcium permeability and magnesium blockade in the NMDA receptor.
1992,
Pubmed
,
Xenbase
Burton,
Sensitivity to flow of intrinsic gating in inwardly rectifying potassium channel from mammalian skeletal muscle.
1990,
Pubmed
Ciani,
Ion permeation and rectification in ATP-sensitive channels from insulin-secreting cells (RINm5F): effects of K+, Na+ and Mg2+.
1988,
Pubmed
Hartmann,
Exchange of conduction pathways between two related K+ channels.
1991,
Pubmed
,
Xenbase
Heginbotham,
The aromatic binding site for tetraethylammonium ion on potassium channels.
1992,
Pubmed
Heginbotham,
A functional connection between the pores of distantly related ion channels as revealed by mutant K+ channels.
1992,
Pubmed
,
Xenbase
Hille,
Potassium channels as multi-ion single-file pores.
1978,
Pubmed
Ho,
Cloning and expression of an inwardly rectifying ATP-regulated potassium channel.
1993,
Pubmed
,
Xenbase
Horie,
Voltage-dependent magnesium block of adenosine-triphosphate-sensitive potassium channel in guinea-pig ventricular cells.
1987,
Pubmed
Kakei,
Properties of adenosine-triphosphate-regulated potassium channels in guinea-pig ventricular cells.
1985,
Pubmed
Kelly,
Inwardly rectifying potassium current in rabbit osteoclasts: a whole-cell and single-channel study.
1992,
Pubmed
Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase
Kurachi,
Voltage-dependent activation of the inward-rectifier potassium channel in the ventricular cell membrane of guinea-pig heart.
1985,
Pubmed
MacKinnon,
Mutations affecting TEA blockade and ion permeation in voltage-activated K+ channels.
1990,
Pubmed
MacKinnon,
Mapping the receptor site for charybdotoxin, a pore-blocking potassium channel inhibitor.
1990,
Pubmed
,
Xenbase
MacKinnon,
Mutant potassium channels with altered binding of charybdotoxin, a pore-blocking peptide inhibitor.
1989,
Pubmed
,
Xenbase
Marty,
Blocking of large unitary calcium-dependent potassium currents by internal sodium ions.
1983,
Pubmed
Matsuda,
Effects of external and internal K+ ions on magnesium block of inwardly rectifying K+ channels in guinea-pig heart cells.
1991,
Pubmed
Matsuda,
Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+.
,
Pubmed
Matsuda,
Open-state substructure of inwardly rectifying potassium channels revealed by magnesium block in guinea-pig heart cells.
1988,
Pubmed
Matsuda,
Triple-barrel structure of inwardly rectifying K+ channels revealed by Cs+ and Rb+ block in guinea-pig heart cells.
1989,
Pubmed
Mori,
Identification by mutagenesis of a Mg(2+)-block site of the NMDA receptor channel.
1992,
Pubmed
,
Xenbase
Oliva,
The mechanism of rectification of iK1 in canine Purkinje myocytes.
1990,
Pubmed
Papazian,
Alteration of voltage-dependence of Shaker potassium channel by mutations in the S4 sequence.
1991,
Pubmed
,
Xenbase
Sakimura,
Functional expression from cloned cDNAs of glutamate receptor species responsive to kainate and quisqualate.
1990,
Pubmed
,
Xenbase
Takumi,
Cloning of a membrane protein that induces a slow voltage-gated potassium current.
1988,
Pubmed
,
Xenbase
Vandenberg,
Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions.
1987,
Pubmed
Wang,
A potassium channel in the apical membrane of rabbit thick ascending limb of Henle's loop.
1990,
Pubmed
Wang,
Regulation of small-conductance K+ channel in apical membrane of rat cortical collecting tubule.
1990,
Pubmed
Wei,
K+ current diversity is produced by an extended gene family conserved in Drosophila and mouse.
1990,
Pubmed
,
Xenbase
Woodhull,
Ionic blockage of sodium channels in nerve.
1973,
Pubmed
Yellen,
Mutations affecting internal TEA blockade identify the probable pore-forming region of a K+ channel.
1991,
Pubmed
Yellen,
Relief of Na+ block of Ca2+-activated K+ channels by external cations.
1984,
Pubmed