Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Control of rectification and permeation by two distinct sites after the second transmembrane region in Kir2.1 K+ channel.
Kubo Y, Murata Y.
???displayArticle.abstract???
1. The rectification property of the inward rectifier K+ channel is chiefly due to the block of outward current by cytoplasmic Mg2+ and polyamines. In the cloned inward rectifier K+ channel Kir2.1 (IRK1), Asp172 in the second transmembrane region (M2) and Glu224 in the putative cytoplasmic region after M2 are reported to be critical for the sensitivity to these blockers. However, the difference in the inward rectification properties between Kir2.1 and a very weak inward rectifier sWIRK could not be explained by differences at these two sites. 2. Following sequence comparison of Kir2.1 and sWIRK, we focused this study on Glu299 located in the centre of the putative cytoplasmic region after M2. Single-point mutants of Kir2.1 (Glu224Gly and Glu299Ser) and a double-point mutant (Glu224Gly-Glu299Ser) were made and expressed in Xenopus oocytes or in HEK293T cells. 3. Their electrophysiological properties were compared with those of wild-type (WT) Kir2.1 and the following observations were made. (a) Glu299Ser showed a weaker inward rectification, a slower activation upon hyperpolarization, a slower decay of the outward current upon depolarization, a lower sensitivity to block by cytoplasmic spermine and a smaller single-channel conductance than WT. (b) The features of Glu224Gly were similar to those of Glu299Ser. (c) In the double mutant (Glu224Gly-Glu299Ser), the differences from WT described above were more prominent. 4. These results demonstrate that Glu299 as well as Glu224 control rectification and permeation, and suggest the possibility that the two sites contribute to the inner vestibule of the channel pore. The slowing down of the on- and off-blocking processes by mutation of these sites implies that Glu224 and Glu299 function to facilitate the entry (and exit) of spermine to (and from) the blocking site.
Bond,
Cloning and expression of a family of inward rectifier potassium channels.
1994, Pubmed,
Xenbase
Bond,
Cloning and expression of a family of inward rectifier potassium channels.
1994,
Pubmed
,
Xenbase Capener,
Homology modeling and molecular dynamics simulation studies of an inward rectifier potassium channel.
2000,
Pubmed Dascal,
Atrial G protein-activated K+ channel: expression cloning and molecular properties.
1993,
Pubmed
,
Xenbase Döring,
The epithelial inward rectifier channel Kir7.1 displays unusual K+ permeation properties.
1998,
Pubmed
,
Xenbase Doyle,
The structure of the potassium channel: molecular basis of K+ conduction and selectivity.
1998,
Pubmed Fabiato,
Calculator programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells.
1979,
Pubmed Fakler,
Strong voltage-dependent inward rectification of inward rectifier K+ channels is caused by intracellular spermine.
1995,
Pubmed
,
Xenbase Ficker,
Spermine and spermidine as gating molecules for inward rectifier K+ channels.
1994,
Pubmed
,
Xenbase Guo,
Mechanism of IRK1 channel block by intracellular polyamines.
2000,
Pubmed
,
Xenbase Ho,
Cloning and expression of an inwardly rectifying ATP-regulated potassium channel.
1993,
Pubmed
,
Xenbase Iizuka,
Functional characterization and localization of a cardiac-type inwardly rectifying K+ channel.
1995,
Pubmed
,
Xenbase Inagaki,
Reconstitution of IKATP: an inward rectifier subunit plus the sulfonylurea receptor.
1995,
Pubmed Inagaki,
Cloning and functional characterization of a novel ATP-sensitive potassium channel ubiquitously expressed in rat tissues, including pancreatic islets, pituitary, skeletal muscle, and heart.
1995,
Pubmed
,
Xenbase Ishihara,
The tetravalent organic cation spermine causes the gating of the IRK1 channel expressed in murine fibroblast cells.
1996,
Pubmed Koyama,
Molecular cloning, functional expression and localization of a novel inward rectifier potassium channel in the rat brain.
1994,
Pubmed
,
Xenbase Krapivinsky,
A novel inward rectifier K+ channel with unique pore properties.
1998,
Pubmed Krapivinsky,
The G-protein-gated atrial K+ channel IKACh is a heteromultimer of two inwardly rectifying K(+)-channel proteins.
1995,
Pubmed
,
Xenbase Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase Kubo,
A weakly inward rectifying potassium channel of the salmon brain. Glutamate 179 in the second transmembrane domain is insufficient for strong rectification.
1996,
Pubmed Kubo,
Primary structure and functional expression of a rat G-protein-coupled muscarinic potassium channel.
1993,
Pubmed
,
Xenbase Lee,
Novel gating mechanism of polyamine block in the strong inward rectifier K channel Kir2.1.
1999,
Pubmed
,
Xenbase Lesage,
Cloning provides evidence for a family of inward rectifier and G-protein coupled K+ channels in the brain.
1994,
Pubmed
,
Xenbase Lopatin,
Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification.
1994,
Pubmed
,
Xenbase Lopatin,
The mechanism of inward rectification of potassium channels: "long-pore plugging" by cytoplasmic polyamines.
1995,
Pubmed
,
Xenbase Loussouarn,
Structure and dynamics of the pore of inwardly rectifying K(ATP) channels.
2000,
Pubmed Lu,
Cytoplasmic amino and carboxyl domains form a wide intracellular vestibule in an inwardly rectifying potassium channel.
1999,
Pubmed
,
Xenbase Lu,
Architecture of a K+ channel inner pore revealed by stoichiometric covalent modification.
1999,
Pubmed
,
Xenbase Lu,
Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel.
1994,
Pubmed
,
Xenbase Matsuda,
Open-state substructure of inwardly rectifying potassium channels revealed by magnesium block in guinea-pig heart cells.
1988,
Pubmed Matsuda,
Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+.
,
Pubmed Minor,
Transmembrane structure of an inwardly rectifying potassium channel.
1999,
Pubmed Nichols,
Inward rectifier potassium channels.
1997,
Pubmed Niwa,
Efficient selection for high-expression transfectants with a novel eukaryotic vector.
1991,
Pubmed Oishi,
Neutralization of aspartate residues in the murine inwardly rectifying K+ channel IRK1 affects the substate behaviour in Mg2+ block.
1998,
Pubmed Sabirov,
A conserved arginine residue in the pore region of an inward rectifier K channel (IRK1) as an external barrier for cationic blockers.
1997,
Pubmed
,
Xenbase Stanfield,
A single aspartate residue is involved in both intrinsic gating and blockage by Mg2+ of the inward rectifier, IRK1.
1994,
Pubmed Taglialatela,
C-terminus determinants for Mg2+ and polyamine block of the inward rectifier K+ channel IRK1.
1995,
Pubmed
,
Xenbase Takumi,
A novel ATP-dependent inward rectifier potassium channel expressed predominantly in glial cells.
1995,
Pubmed
,
Xenbase Thompson,
Residues beyond the selectivity filter of the K+ channel kir2.1 regulate permeation and block by external Rb+ and Cs+.
2000,
Pubmed Töpert,
Kir2.4: a novel K+ inward rectifier channel associated with motoneurons of cranial nerve nuclei.
1998,
Pubmed
,
Xenbase Vandenberg,
Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions.
1987,
Pubmed Watanabe,
Estimation of polyamine binding to macromolecules and ATP in bovine lymphocytes and rat liver.
1991,
Pubmed Wible,
Gating of inwardly rectifying K+ channels localized to a single negatively charged residue.
1994,
Pubmed
,
Xenbase Yang,
Control of rectification and permeation by residues in two distinct domains in an inward rectifier K+ channel.
1995,
Pubmed
,
Xenbase
