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.
Biophys J
2008 Feb 15;944:1241-51. doi: 10.1529/biophysj.107.117796.
Show Gene links
Show Anatomy links
Mechanism of the modulation of Kv4:KChIP-1 channels by external K+.
Kaulin YA
,
De Santiago-Castillo JA
,
Rocha CA
,
Covarrubias M
.
???displayArticle.abstract???
In response to a prolonged membrane depolarization, inactivation autoregulates the activity of voltage-gated ion channels. Slow inactivation involving a localized constriction of the selectivity filter (P/C-type mechanism) is prevalent in many voltage-gated K(+) channels of the Kv1 subfamily. However, the generalization of this mechanism to other Kv channel subfamilies has remained uncertain and controversial. In agreement with a "foot-in-the-door" mechanism and the presence of ion-ion interactions in the pore, elevated external K(+) slows the development of P/C-type inactivation and accelerates its recovery. In sharp contrast and resembling the regulation of the hippocampal A-type K(+) current, we found that Kv4.x channels associated with KChIP-1 (an auxiliary subunit) exhibit accelerated inactivation and unaffected recovery from inactivation when exposed to elevated external K(+). This regulation depends on the ability of a permeant ion to enter the selectivity filter (K(+) = Rb(+) = NH4(+) > Cs(+) > Na(+)); and the apparent equilibrium dissociation constant of a single regulatory site is 8 mM for K(+). By applying a robust quantitative global kinetic modeling approach to all macroscopic properties over a 210-mV range of membrane potentials, we determined that elevated external K(+) inhibits unstable closed states outside the main activation pathway and thereby promotes preferential closed-state inactivation. These results suggest the presence of a vestigial and unstable P/C-type mechanism of inactivation in Kv4 channels and strengthen the concept of novel mechanisms of closed-state inactivation. Regulation of Kv4 channel inactivation by hyperkalemia may help to explain the pathophysiology of electrolyte imbalances in excitable tissues.
Ayer,
Enhanced closed-state inactivation in a mutant Shaker K+ channel.
1997, Pubmed,
Xenbase
Ayer,
Enhanced closed-state inactivation in a mutant Shaker K+ channel.
1997,
Pubmed
,
Xenbase
Baukrowitz,
Modulation of K+ current by frequency and external [K+]: a tale of two inactivation mechanisms.
1995,
Pubmed
Beck,
Remodelling inactivation gating of Kv4 channels by KChIP1, a small-molecular-weight calcium-binding protein.
2002,
Pubmed
,
Xenbase
Beck,
Kv4 channels exhibit modulation of closed-state inactivation in inside-out patches.
2001,
Pubmed
,
Xenbase
Bähring,
Kinetic analysis of open- and closed-state inactivation transitions in human Kv4.2 A-type potassium channels.
2001,
Pubmed
Choi,
Tetraethylammonium blockade distinguishes two inactivation mechanisms in voltage-activated K+ channels.
1991,
Pubmed
Claydon,
A direct demonstration of closed-state inactivation of K+ channels at low pH.
2007,
Pubmed
,
Xenbase
Cordero-Morales,
Molecular determinants of gating at the potassium-channel selectivity filter.
2006,
Pubmed
De Biasi,
Inactivation determined by a single site in K+ pores.
1993,
Pubmed
Eghbali,
External pore collapse as an inactivation mechanism for Kv4.3 K+ channels.
2002,
Pubmed
Gandhi,
Reconstructing voltage sensor-pore interaction from a fluorescence scan of a voltage-gated K+ channel.
2000,
Pubmed
Gebauer,
N-type inactivation features of Kv4.2 channel gating.
2004,
Pubmed
Hoshi,
Two types of inactivation in Shaker K+ channels: effects of alterations in the carboxy-terminal region.
1991,
Pubmed
,
Xenbase
Islas,
Voltage sensitivity and gating charge in Shaker and Shab family potassium channels.
1999,
Pubmed
,
Xenbase
Jerng,
K+ channel inactivation mediated by the concerted action of the cytoplasmic N- and C-terminal domains.
1997,
Pubmed
,
Xenbase
Jerng,
Inactivation gating of Kv4 potassium channels: molecular interactions involving the inner vestibule of the pore.
1999,
Pubmed
,
Xenbase
Jerng,
Molecular physiology and modulation of somatodendritic A-type potassium channels.
2004,
Pubmed
Jerng,
Multiprotein assembly of Kv4.2, KChIP3 and DPP10 produces ternary channel complexes with ISA-like properties.
2005,
Pubmed
,
Xenbase
Jurman,
Visual identification of individual transfected cells for electrophysiology using antibody-coated beads.
1994,
Pubmed
Kim,
Kv4 potassium channel subunits control action potential repolarization and frequency-dependent broadening in rat hippocampal CA1 pyramidal neurones.
2005,
Pubmed
Kim,
Regulation of dendritic excitability by activity-dependent trafficking of the A-type K+ channel subunit Kv4.2 in hippocampal neurons.
2007,
Pubmed
Kirichok,
[K+]out accelerates inactivation of Shal-channels responsible for A-current in rat CA1 neurons.
1998,
Pubmed
Kiss,
Modulation of C-type inactivation by K+ at the potassium channel selectivity filter.
1998,
Pubmed
Kiss,
Contribution of the selectivity filter to inactivation in potassium channels.
1999,
Pubmed
Klemic,
Inactivation of Kv2.1 potassium channels.
1998,
Pubmed
,
Xenbase
Klemic,
U-type inactivation of Kv3.1 and Shaker potassium channels.
2001,
Pubmed
,
Xenbase
Kurata,
A structural interpretation of voltage-gated potassium channel inactivation.
2006,
Pubmed
Kurata,
Separation of P/C- and U-type inactivation pathways in Kv1.5 potassium channels.
2005,
Pubmed
Larsson,
A conserved glutamate is important for slow inactivation in K+ channels.
2000,
Pubmed
,
Xenbase
Lauver,
Manipulating Kv4.2 identifies a specific component of hippocampal pyramidal neuron A-current that depends upon Kv4.2 expression.
2006,
Pubmed
Leis,
Potassium homeostasis in the ischemic brain.
2005,
Pubmed
Levy,
Recovery from C-type inactivation is modulated by extracellular potassium.
1996,
Pubmed
Levy,
A voltage-dependent role for K+ in recovery from C-type inactivation.
1996,
Pubmed
Liu,
Dynamic rearrangement of the outer mouth of a K+ channel during gating.
1996,
Pubmed
Loots,
Protein rearrangements underlying slow inactivation of the Shaker K+ channel.
1998,
Pubmed
López-Barneo,
Effects of external cations and mutations in the pore region on C-type inactivation of Shaker potassium channels.
1993,
Pubmed
,
Xenbase
Matteson,
External monovalent cations that impede the closing of K channels.
1986,
Pubmed
Ogielska,
Cooperative subunit interactions in C-type inactivation of K channels.
1995,
Pubmed
,
Xenbase
Ogielska,
Functional consequences of a decreased potassium affinity in a potassium channel pore. Ion interactions and C-type inactivation.
1999,
Pubmed
,
Xenbase
Olcese,
Correlation between charge movement and ionic current during slow inactivation in Shaker K+ channels.
1997,
Pubmed
,
Xenbase
Olcese,
A conducting state with properties of a slow inactivated state in a shaker K(+) channel mutant.
2001,
Pubmed
,
Xenbase
Panyi,
Cross talk between activation and slow inactivation gates of Shaker potassium channels.
2006,
Pubmed
Panyi,
C-type inactivation of a voltage-gated K+ channel occurs by a cooperative mechanism.
1995,
Pubmed
Parham,
Hyperkalemia revisited.
2006,
Pubmed
Patel,
Transient outward potassium current, 'Ito', phenotypes in the mammalian left ventricle: underlying molecular, cellular and biophysical mechanisms.
2005,
Pubmed
Pioletti,
Three-dimensional structure of the KChIP1-Kv4.3 T1 complex reveals a cross-shaped octamer.
2006,
Pubmed
,
Xenbase
Rasmusson,
Inactivation of voltage-gated cardiac K+ channels.
1998,
Pubmed
Ray,
A trapped intracellular cation modulates K+ channel recovery from slow inactivation.
2006,
Pubmed
Schoppa,
Activation of Shaker potassium channels. III. An activation gating model for wild-type and V2 mutant channels.
1998,
Pubmed
,
Xenbase
Shahidullah,
The link between ion permeation and inactivation gating of Kv4 potassium channels.
2003,
Pubmed
,
Xenbase
Shin,
Inactivation in HCN channels results from reclosure of the activation gate: desensitization to voltage.
2004,
Pubmed
Swenson,
K+ channels close more slowly in the presence of external K+ and Rb+.
1981,
Pubmed
Wang,
Structural basis for modulation of Kv4 K+ channels by auxiliary KChIP subunits.
2007,
Pubmed
,
Xenbase
Wang,
Time- and voltage-dependent components of Kv4.3 inactivation.
2005,
Pubmed
,
Xenbase
Yellen,
The moving parts of voltage-gated ion channels.
1998,
Pubmed
Zagotta,
Shaker potassium channel gating. II: Transitions in the activation pathway.
1994,
Pubmed
,
Xenbase
Zhou,
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.
2001,
Pubmed
