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.
The link between ion permeation and inactivation gating of Kv4 potassium channels.
Shahidullah M, Covarrubias M.
???displayArticle.abstract???
Kv4 potassium channels undergo rapid inactivation but do not seem to exhibit the classical N-type and C-type mechanisms present in other Kv channels. We have previously hypothesized that Kv4 channels preferentially inactivate from the preopen closed state, which involves regions of the channel that contribute to the internal vestibule of the pore. To further test this hypothesis, we have examined the effects of permeant ions on gating of three Kv4 channels (Kv4.1, Kv4.2, and Kv4.3) expressed in Xenopus oocytes. Rb(+) is an excellent tool for this purpose because its prolonged residency time in the pore delays K(+) channel closing. The data showed that, only when Rb(+) carried the current, both channel closing and the development of macroscopic inactivation are slowed (1.5- to 4-fold, relative to the K(+) current). Furthermore, macroscopic Rb(+) currents were larger than K(+) currents (1.2- to 3-fold) as the result of a more stable open state, which increases the maximum open probability. These results demonstrate that pore occupancy can influence inactivation gating in a manner that depends on how channel closing impacts inactivation from the preopen closed state. By examining possible changes in ionic selectivity and the influence of elevating the external K(+) concentration, additional experiments did not support the presence of C-type inactivation in Kv4 channels.
Bähring,
Kinetic analysis of open- and closed-state inactivation transitions in human Kv4.2 A-type potassium channels.
2001, Pubmed
Bähring,
Kinetic analysis of open- and closed-state inactivation transitions in human Kv4.2 A-type potassium channels.
2001,
Pubmed Baukrowitz,
Modulation of K+ current by frequency and external [K+]: a tale of two inactivation mechanisms.
1995,
Pubmed Beck,
Kv4 channels exhibit modulation of closed-state inactivation in inside-out patches.
2001,
Pubmed
,
Xenbase Beck,
Remodelling inactivation gating of Kv4 channels by KChIP1, a small-molecular-weight calcium-binding protein.
2002,
Pubmed
,
Xenbase Chen,
Allosteric effects of permeating cations on gating currents during K+ channel deactivation.
1997,
Pubmed Demo,
The inactivation gate of the Shaker K+ channel behaves like an open-channel blocker.
1991,
Pubmed Demo,
Ion effects on gating of the Ca(2+)-activated K+ channel correlate with occupancy of the pore.
1992,
Pubmed Ding,
Tail end of the s6 segment: role in permeation in shaker potassium channels.
2002,
Pubmed Doyle,
The structure of the potassium channel: molecular basis of K+ conduction and selectivity.
1998,
Pubmed Eisenman,
Multi-ion conduction and selectivity in the high-conductance Ca++-activated K+ channel from skeletal muscle.
1986,
Pubmed Frazier,
Apparent change in ion selectivity caused by changes in intracellular K(+) during whole-cell recording.
2000,
Pubmed Gómez-Lagunas,
The relation between ion permeation and recovery from inactivation of ShakerB K+ channels.
1994,
Pubmed Holmqvist,
Elimination of fast inactivation in Kv4 A-type potassium channels by an auxiliary subunit domain.
2002,
Pubmed
,
Xenbase Hoshi,
Two types of inactivation in Shaker K+ channels: effects of alterations in the carboxy-terminal region.
1991,
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 Kirichok,
[K+]out accelerates inactivation of Shal-channels responsible for A-current in rat CA1 neurons.
1998,
Pubmed Kiss,
Contribution of the selectivity filter to inactivation in potassium channels.
1999,
Pubmed Ledwell,
Mutations in the S4 region isolate the final voltage-dependent cooperative step in potassium channel activation.
1999,
Pubmed
,
Xenbase Levy,
A voltage-dependent role for K+ in recovery from C-type inactivation.
1996,
Pubmed Levy,
Recovery from C-type inactivation is modulated by extracellular potassium.
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 Morais-Cabral,
Energetic optimization of ion conduction rate by the K+ selectivity filter.
2001,
Pubmed Ogielska,
Cooperative subunit interactions in C-type inactivation of K channels.
1995,
Pubmed
,
Xenbase Ogielska,
A mutation in S6 of Shaker potassium channels decreases the K+ affinity of an ion binding site revealing ion-ion interactions in the pore.
1998,
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 Panyi,
C-type inactivation of a voltage-gated K+ channel occurs by a cooperative mechanism.
1995,
Pubmed Pardo,
Extracellular K+ specifically modulates a rat brain K+ channel.
1992,
Pubmed
,
Xenbase Perozo,
Gating currents from a nonconducting mutant reveal open-closed conformations in Shaker K+ channels.
1993,
Pubmed Ruppersberg,
Cloned neuronal IK(A) channels reopen during recovery from inactivation.
1991,
Pubmed Sala,
Voltage-dependent slowing of K channel closing kinetics by Rb+.
1991,
Pubmed Schoppa,
Activation of shaker potassium channels. I. Characterization of voltage-dependent transitions.
1998,
Pubmed
,
Xenbase Starkus,
Ion conduction through C-type inactivated Shaker channels.
1997,
Pubmed
,
Xenbase Starkus,
Voltage dependence of slow inactivation in Shaker potassium channels results from changes in relative K(+) and Na(+) permeabilities.
2000,
Pubmed
,
Xenbase Starkus,
Macroscopic Na+ currents in the "Nonconducting" Shaker potassium channel mutant W434F.
1998,
Pubmed
,
Xenbase Swenson,
K+ channels close more slowly in the presence of external K+ and Rb+.
1981,
Pubmed Townsend,
Anomalous effect of permeant ion concentration on peak open probability of cardiac Na+ channels.
1997,
Pubmed
,
Xenbase Yang,
How does the W434F mutation block current in Shaker potassium channels?
1997,
Pubmed
,
Xenbase Yeh,
Immobilisation of gating charge by a substance that simulates inactivation.
1978,
Pubmed Yellen,
Keeping K+ completely comfortable.
2001,
Pubmed 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 Zheng,
Selectivity changes during activation of mutant Shaker potassium channels.
1997,
Pubmed
,
Xenbase Zheng,
Hidden Markov model analysis of intermediate gating steps associated with the pore gate of shaker potassium channels.
2001,
Pubmed
,
Xenbase Zhou,
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.
2001,
Pubmed
