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Biochem J
2006 Feb 01;393Pt 3:645-55. doi: 10.1042/BJ20051380.
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Interactive domains between pore loops of the yeast K+ channel TOK1 associate with extracellular K+ sensitivity.
Johansson I
,
Blatt MR
.
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Gating of the outward-rectifying K+ channel TOK1 of Saccharomyces cerevisiae is controlled by membrane voltage and extracellular K+ concentration. Previous studies identified two kinetically distinct effects of K+, and site-mutagenic analysis associated these K+-dependencies with domains of the extracellular turrets of the channel protein. We have mapped the TOK1 pore domains to extant K+ channel crystal structures to target additional residues contributing to TOK1 gating. Leu270, located in the first pore domain of TOK1, was found to be critical for gating and its K+ sensitivity. Analysis of amino acid substitutions indicated that spatial position of the polypeptide backbone is a primary factor determining gating sensitivity to K+. The strongest effects, with L270Y, L270F and L270W, led to more than a 30-fold decrease in apparent K+ affinity and an inversion in the apparent K+-dependence of voltage-dependent gating compared with the wild-type current. A partial rescue of wild-type gating was obtained on substitution in the second pore domain with the double mutant L270D/A428Y. These, and additional results, demarcate extracellular domains that are associated with the K+-sensitivity of TOK1 and they offer primary evidence for a synergy in gating between the two pore domains of TOK1, demonstrating an unexpected degree of long-distance interaction across the mouth of the K+ channel.
Ache,
GORK, a delayed outward rectifier expressed in guard cells of Arabidopsis thaliana, is a K(+)-selective, K(+)-sensing ion channel.
2000, Pubmed,
Xenbase
Ache,
GORK, a delayed outward rectifier expressed in guard cells of Arabidopsis thaliana, is a K(+)-selective, K(+)-sensing ion channel.
2000,
Pubmed
,
Xenbase
Baukrowitz,
Use-dependent blockers and exit rate of the last ion from the multi-ion pore of a K+ channel.
1996,
Pubmed
Bertl,
Physiological characterization of the yeast plasma membrane outward rectifying K+ channel, DUK1 (TOK1), in situ.
1998,
Pubmed
Blatt,
K(+)-sensitive gating of the K+ outward rectifier in Vicia guard cells.
1997,
Pubmed
Czempinski,
New structure and function in plant K+ channels: KCO1, an outward rectifier with a steep Ca2+ dependency.
1997,
Pubmed
Dahlmann,
Regulation of Kir channels by intracellular pH and extracellular K(+): mechanisms of coupling.
2004,
Pubmed
,
Xenbase
Doi,
Extracellular K+ and intracellular pH allosterically regulate renal Kir1.1 channels.
1996,
Pubmed
,
Xenbase
Doyle,
The structure of the potassium channel: molecular basis of K+ conduction and selectivity.
1998,
Pubmed
Gaymard,
Identification and disruption of a plant shaker-like outward channel involved in K+ release into the xylem sap.
1998,
Pubmed
,
Xenbase
Geiger,
Outer pore residues control the H(+) and K(+) sensitivity of the Arabidopsis potassium channel AKT3.
2002,
Pubmed
,
Xenbase
Gonzalez,
S3b amino acid residues do not shuttle across the bilayer in voltage-dependent Shaker K+ channels.
2005,
Pubmed
,
Xenbase
Guex,
SWISS-MODEL and the Swiss-PdbViewer: an environment for comparative protein modeling.
1997,
Pubmed
Jiang,
Crystal structure and mechanism of a calcium-gated potassium channel.
2002,
Pubmed
Jiang,
The open pore conformation of potassium channels.
2002,
Pubmed
Jiang,
X-ray structure of a voltage-dependent K+ channel.
2003,
Pubmed
Johansson,
External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism.
2006,
Pubmed
Ketchum,
A new family of outwardly rectifying potassium channel proteins with two pore domains in tandem.
1995,
Pubmed
,
Xenbase
Kiss,
Modulation of C-type inactivation by K+ at the potassium channel selectivity filter.
1998,
Pubmed
Latorre,
Molecular coupling between voltage sensor and pore opening in the Arabidopsis inward rectifier K+ channel KAT1.
2003,
Pubmed
Lesage,
TWIK-1, a ubiquitous human weakly inward rectifying K+ channel with a novel structure.
1996,
Pubmed
,
Xenbase
Lesage,
A pH-sensitive yeast outward rectifier K+ channel with two pore domains and novel gating properties.
1996,
Pubmed
,
Xenbase
LiCata,
Long-range, small magnitude nonadditivity of mutational effects in proteins.
1995,
Pubmed
Long,
Voltage sensor of Kv1.2: structural basis of electromechanical coupling.
2005,
Pubmed
Long,
Crystal structure of a mammalian voltage-dependent Shaker family K+ channel.
2005,
Pubmed
Loukin,
K(+)-dependent composite gating of the yeast K(+) channel, Tok1.
1999,
Pubmed
,
Xenbase
Loukin,
Carboxyl tail prevents yeast K(+) channel closure: proposal of an integrated model of TOK1 gating.
2002,
Pubmed
Loukin,
The carboxyl tail forms a discrete functional domain that blocks closure of the yeast K+ channel.
2002,
Pubmed
López-Barneo,
Effects of external cations and mutations in the pore region on C-type inactivation of Shaker potassium channels.
1993,
Pubmed
,
Xenbase
Mannuzzu,
Independence and cooperativity in rearrangements of a potassium channel voltage sensor revealed by single subunit fluorescence.
2000,
Pubmed
,
Xenbase
Melishchuk,
Loss of shaker K channel conductance in 0 K+ solutions: role of the voltage sensor.
1998,
Pubmed
Männikkö,
Voltage-sensing mechanism is conserved among ion channels gated by opposite voltages.
2002,
Pubmed
,
Xenbase
Pathak,
The cooperative voltage sensor motion that gates a potassium channel.
2005,
Pubmed
,
Xenbase
Roelfsema,
Ion channels in guard cells of Arabidopsis thaliana (L.) Heynh.
1997,
Pubmed
Sackin,
Permeant cations and blockers modulate pH gating of ROMK channels.
2003,
Pubmed
,
Xenbase
Saldaña,
Splitting the two pore domains from TOK1 results in two cationic channels with novel functional properties.
2002,
Pubmed
,
Xenbase
Schroeder,
Quantitative analysis of outward rectifying K+ channel currents in guard cell protoplasts from Vicia faba.
1989,
Pubmed
Schulte,
K(+)-dependent gating of K(ir)1.1 channels is linked to pH gating through a conformational change in the pore.
2001,
Pubmed
,
Xenbase
Schwede,
SWISS-MODEL: An automated protein homology-modeling server.
2003,
Pubmed
Sesti,
Hyperpolarization moves S4 sensors inward to open MVP, a methanococcal voltage-gated potassium channel.
2003,
Pubmed
Smith-Maxwell,
Role of the S4 in cooperativity of voltage-dependent potassium channel activation.
1998,
Pubmed
,
Xenbase
Vergani,
Extracellular K+ and Ba2+ mediate voltage-dependent inactivation of the outward-rectifying K+ channel encoded by the yeast gene TOK1.
1997,
Pubmed
,
Xenbase
Vergani,
Mutations in the pore regions of the yeast K+ channel YKC1 affect gating by extracellular K+.
1998,
Pubmed
,
Xenbase
Vergani,
Mutations in the yeast two pore K+ channel YKC1 identify functional differences between the pore domains.
1999,
Pubmed
,
Xenbase
Zhou,
YKC1 encodes the depolarization-activated K+ channel in the plasma membrane of yeast.
1995,
Pubmed
