Properties of Deactivation Gating Currents in Shaker Channels
نویسندگان
چکیده
منابع مشابه
Fast Inactivation in Shaker K 1 Channels Properties of Ionic and Gating Currents
Fast inactivating Shaker H4 potassium channels and nonconducting pore mutant Shaker H4 W434F channels have been used to correlate the installation and recovery of the fast inactivation of ionic current with changes in the kinetics of gating current known as “charge immobilization” (Armstrong, C.M., and F. Bezanilla. 1977. J. Gen. Physiol. 70:567–590.). Shaker H4 W434F gating currents are very s...
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Ionic (Ii) and gating currents (Ig) from noninactivating Shaker H4 K+ channels were recorded with the cut-open oocyte voltage clamp and macropatch techniques. Steady state and kinetic properties were studied in the temperature range 2-22 degreesC. The time course of Ii elicited by large depolarizations consists of an initial delay followed by an exponential rise with two kinetic components. The...
متن کاملDeactivation retards recovery from inactivation in Shaker K+ channels.
In Na+ channels, recovery from inactivation begins with a delay, followed by an exponential course, and hyperpolarization shortens the delay as well as hastens the entire exponential phase. These findings have been taken to indicate that Na+ channels must deactivate to recover from inactivation, and deactivation facilitates the unbinding of the inactivating particle. In contrast, it is demonstr...
متن کاملIntermediate Conductances during Deactivation of Heteromultimeric Shaker Potassium Channels
A previous study of the T442S mutant Shaker channel revealed activation-coupled subconductance levels that apparently represent kinetic intermediates in channel activation (Zheng, J., and F.J. Sigworth. 1997. J. Gen. Physiol. 110:101-117). We have now extended the study to heteromultimeric channels consisting of various numbers of mutant subunits as well as channels without mutant subunits, all...
متن کاملElectrostatics and the Gating Pore of Shaker Potassium Channels
Various experiments have suggested that the S4 segment in voltage-dependent Na(+) and K(+) channels is in contact with a solvent-accessible cavity. We explore the consequences of the existence of such a cavity through the electrostatic effects on the gating currents of Shaker K(+) channels under conditions of reduced ionic strength S. We observe that approximately 10-fold reductions of intracel...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2011
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2011.01.043