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.
Gating of I(sK) channels expressed in Xenopus oocytes.
Tzounopoulos T, Maylie J, Adelman JP.
???displayArticle.abstract???
The channel underlying the slow component of the voltage-dependent delayed outward rectifier K+ current, I(Ks), in heart is composed of the minK and KvLQT1 proteins. Expression of the minK protein in Xenopus oocytes results in I(Ks)-like currents, I(sK), due to coassembly with the endogenous XKvLQT1. The kinetics and voltage-dependent characteristics of I(sK) suggest a distinct mechanism for voltage-dependent gating. Currents recorded at 40 mV from holding potentials between -60 and -120 mV showed an unusual "cross-over," with the currents obtained from more depolarized holding potentials activating more slowly and deviating from the Cole-Moore prediction. Analysis of the current traces revealed two components with fast and slow kinetics that were not affected by the holding potential. Rather, the relative contribution of the fast component decreased with depolarized holding potentials. Deactivation and reactivation, after a short period of repolarization (100 ms), was markedly faster than the fast component of activation. These gating properties suggest a physiological mechanism by which cardiac I(Ks) may suppress premature action potentials.
Armstrong,
Currents related to movement of the gating particles of the sodium channels.
1973, Pubmed
Armstrong,
Currents related to movement of the gating particles of the sodium channels.
1973,
Pubmed Barhanin,
K(V)LQT1 and lsK (minK) proteins associate to form the I(Ks) cardiac potassium current.
1996,
Pubmed
,
Xenbase Bezanilla,
Gating of Shaker K+ channels: II. The components of gating currents and a model of channel activation.
1994,
Pubmed
,
Xenbase Busch,
An amino acid mutation in a potassium channel that prevents inhibition by protein kinase C.
1992,
Pubmed
,
Xenbase Christie,
Heteropolymeric potassium channels expressed in Xenopus oocytes from cloned subunits.
1990,
Pubmed
,
Xenbase Cui,
Gating of IsK expressed in Xenopus oocytes depends on the amount of mRNA injected.
1994,
Pubmed
,
Xenbase Goldstein,
Site-specific mutations in a minimal voltage-dependent K+ channel alter ion selectivity and open-channel block.
1991,
Pubmed
,
Xenbase Sanguinetti,
Coassembly of K(V)LQT1 and minK (IsK) proteins to form cardiac I(Ks) potassium channel.
1996,
Pubmed
,
Xenbase Stefani,
Gating of Shaker K+ channels: I. Ionic and gating currents.
1994,
Pubmed
,
Xenbase TAYLOR,
Analysis of certain errors in squid axon voltage clamp measurements.
1960,
Pubmed Tzounopoulos,
min K channels form by assembly of at least 14 subunits.
1995,
Pubmed
,
Xenbase Varnum,
The min K channel underlies the cardiac potassium current IKs and mediates species-specific responses to protein kinase C.
1993,
Pubmed
,
Xenbase Varnum,
Persistent activation of min K channels by chemical cross-linking.
1995,
Pubmed
,
Xenbase Wang,
MinK residues line a potassium channel pore.
1996,
Pubmed Zagotta,
Shaker potassium channel gating. II: Transitions in the activation pathway.
1994,
Pubmed
,
Xenbase
