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Biophys J
2008 Jan 15;942:446-56. doi: 10.1529/biophysj.107.108738.
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Modulation of the conductance-voltage relationship of the BK Ca channel by mutations at the putative flexible interface between two RCK domains.
Kim HJ
,
Lim HH
,
Rho SH
,
Bao L
,
Lee JH
,
Cox DH
,
Kim DH
,
Park CS
.
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Calcium-dependent gating of the large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel is conferred by the large cytosolic carboxyl terminus containing two domains of the regulator of K(+) conductance (RCK) and the high-affinity Ca(2+)-binding site (the Ca(2+)-bowl). In our previous study, we located the putative second RCK domain (RCK2) and demonstrated that it interacts directly with RCK1 via a hydrophobic "assembly interface". In this study, we tested the structural model of the other interface, the "flexible interface", by strategically positioning charge pairs across the putative interface. Several charge mutations on RCK2 affected the voltage-dependent activation of the channel. In particular, the Gly-to-Asp substitution at position 803 profoundly affected channel activation by stabilizing the open conformation of the channel with minimal effects on its Ca(2+) affinity and voltage sensitivity. Various mutations at Gly-803 shifted the channel's conductance-voltage curve either left or right over a 145-mV range. Since this residue is predicted to be in the first loop of RCK2 these results strongly suggest that this loop plays a critical role in determining the intrinsic equilibrium constant for channel opening, and they support the hypothesis that this loop is part of an interface that mediates conformational coupling between RCK1 and RCK2.
Ahluwalia,
The large-conductance Ca2+-activated K+ channel is essential for innate immunity.
2004, Pubmed
Ahluwalia,
The large-conductance Ca2+-activated K+ channel is essential for innate immunity.
2004,
Pubmed
Armstrong,
Voltage-gated K channels.
2003,
Pubmed
Bao,
Gating and ionic currents reveal how the BKCa channel's Ca2+ sensitivity is enhanced by its beta1 subunit.
2005,
Pubmed
,
Xenbase
Bao,
Elimination of the BK(Ca) channel's high-affinity Ca(2+) sensitivity.
2002,
Pubmed
,
Xenbase
Bao,
Mapping the BKCa channel's "Ca2+ bowl": side-chains essential for Ca2+ sensing.
2004,
Pubmed
,
Xenbase
Bezanilla,
Voltage sensor movements.
2002,
Pubmed
Bian,
Ca2+-binding activity of a COOH-terminal fragment of the Drosophila BK channel involved in Ca2+-dependent activation.
2001,
Pubmed
Braun,
Contribution of potential EF hand motifs to the calcium-dependent gating of a mouse brain large conductance, calcium-sensitive K(+) channel.
2001,
Pubmed
Brenner,
Vasoregulation by the beta1 subunit of the calcium-activated potassium channel.
2000,
Pubmed
Cox,
Role of the beta1 subunit in large-conductance Ca(2+)-activated K(+) channel gating energetics. Mechanisms of enhanced Ca(2+) sensitivity.
2000,
Pubmed
,
Xenbase
Cox,
Allosteric gating of a large conductance Ca-activated K+ channel.
1997,
Pubmed
,
Xenbase
Cui,
Allosteric linkage between voltage and Ca(2+)-dependent activation of BK-type mslo1 K(+) channels.
2000,
Pubmed
Cui,
Intrinsic voltage dependence and Ca2+ regulation of mslo large conductance Ca-activated K+ channels.
1997,
Pubmed
,
Xenbase
Du,
Calcium-sensitive potassium channelopathy in human epilepsy and paroxysmal movement disorder.
2005,
Pubmed
,
Xenbase
Díaz,
Role of the S4 segment in a voltage-dependent calcium-sensitive potassium (hSlo) channel.
1998,
Pubmed
,
Xenbase
Fettiplace,
Mechanisms of hair cell tuning.
1999,
Pubmed
Gandhi,
Molecular models of voltage sensing.
2002,
Pubmed
Grantham,
Amino acid difference formula to help explain protein evolution.
1974,
Pubmed
Ha,
Functional characteristics of two BKCa channel variants differentially expressed in rat brain tissues.
2000,
Pubmed
,
Xenbase
Horn,
Coupled movements in voltage-gated ion channels.
2002,
Pubmed
Horrigan,
Allosteric voltage gating of potassium channels II. Mslo channel gating charge movement in the absence of Ca(2+).
1999,
Pubmed
Horrigan,
Allosteric voltage gating of potassium channels I. Mslo ionic currents in the absence of Ca(2+).
1999,
Pubmed
,
Xenbase
Horrigan,
Coupling between voltage sensor activation, Ca2+ binding and channel opening in large conductance (BK) potassium channels.
2002,
Pubmed
,
Xenbase
Jiang,
Crystal structure and mechanism of a calcium-gated potassium channel.
2002,
Pubmed
Jiang,
Structure of the RCK domain from the E. coli K+ channel and demonstration of its presence in the human BK channel.
2001,
Pubmed
,
Xenbase
Kim,
Hydrophobic interface between two regulators of K+ conductance domains critical for calcium-dependent activation of large conductance Ca2+-activated K+ channels.
2006,
Pubmed
Lim,
Identification and functional characterization of ankyrin-repeat family protein ANKRA as a protein interacting with BKCa channel.
2005,
Pubmed
Lingle,
Gating rings formed by RCK domains: keys to gate opening.
2007,
Pubmed
Ma,
Role of charged residues in the S1-S4 voltage sensor of BK channels.
2006,
Pubmed
,
Xenbase
Marty,
Ca-dependent K channels with large unitary conductance in chromaffin cell membranes.
1981,
Pubmed
Nelson,
Relaxation of arterial smooth muscle by calcium sparks.
1995,
Pubmed
Pallotta,
Single channel recordings of Ca2+-activated K+ currents in rat muscle cell culture.
1981,
Pubmed
Patton,
Some precautions in using chelators to buffer metals in biological solutions.
2004,
Pubmed
Petkov,
Beta1-subunit of the Ca2+-activated K+ channel regulates contractile activity of mouse urinary bladder smooth muscle.
2001,
Pubmed
Plüger,
Mice with disrupted BK channel beta1 subunit gene feature abnormal Ca(2+) spark/STOC coupling and elevated blood pressure.
2000,
Pubmed
Qian,
Intra- and intersubunit cooperativity in activation of BK channels by Ca2+.
2006,
Pubmed
,
Xenbase
Robitaille,
Functional colocalization of calcium and calcium-gated potassium channels in control of transmitter release.
1993,
Pubmed
Roosild,
Cytoplasmic gatekeepers of K+-channel flux: a structural perspective.
2004,
Pubmed
Rose,
Hydrophobicity of amino acid residues in globular proteins.
1985,
Pubmed
Schreiber,
A novel calcium-sensing domain in the BK channel.
1997,
Pubmed
,
Xenbase
Schreiber,
Transplantable sites confer calcium sensitivity to BK channels.
1999,
Pubmed
,
Xenbase
Wang,
An S6 mutation in BK channels reveals beta1 subunit effects on intrinsic and voltage-dependent gating.
2006,
Pubmed
Wei,
Calcium sensitivity of BK-type KCa channels determined by a separable domain.
1994,
Pubmed
Xia,
Multiple regulatory sites in large-conductance calcium-activated potassium channels.
2002,
Pubmed
Yazejian,
Direct measurements of presynaptic calcium and calcium-activated potassium currents regulating neurotransmitter release at cultured Xenopus nerve-muscle synapses.
1997,
Pubmed
,
Xenbase
Zamyatnin,
Protein volume in solution.
1972,
Pubmed
Zeng,
Divalent cation sensitivity of BK channel activation supports the existence of three distinct binding sites.
2005,
Pubmed
,
Xenbase
Zhang,
Allosteric regulation of BK channel gating by Ca(2+) and Mg(2+) through a nonselective, low affinity divalent cation site.
2001,
Pubmed
,
Xenbase