TU Darmstadt / ULB / TUbiblio

Calcium- and voltage-dependent ion channels in Saccharomyces cerevisiae.

Bertl, A. ; Gradmann, D. ; Slayman, C. L. (1992)
Calcium- and voltage-dependent ion channels in Saccharomyces cerevisiae.
In: Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 338 (1283)
Article, Bibliographie

Abstract

Ion channels in both the tonoplast and the plasma membrane of Saccharomyces cerevisiae have been characterized at the single channel level by patch-clamp techniques. The predominant tonoplast channel is cation selective, has an open-channel conductance of 120 pS in 100 mM KCl, and conducts Na+ or K+ equally well, and Ca2+ to a lesser extent. Its open probability (Po) is voltage-dependent, peaking at about -80 mV (cytoplasm negative), and falling to near zero at +80 mV. Elevated cytoplasmic Ca2+, alkaline cytoplasmic pH, and reducing agents activate the channel. The predominant plasma membrane channel is highly selective for K+ over anions and other cations, and shows strong outward rectification of the time-averaged current-voltage curves in cell-attached experiments. In isolated inside-out patches with micromolar cytoplasmic Ca2+, this channel is activated by positive going membrane voltages: mean Po is zero at negative membrane voltages and near unity at 100 mV. At moderate positive membrane voltages (20-40 mV), elevating cytoplasmic Ca2+ activates the channel to open in bursts of several hundred milliseconds duration. At higher positive membrane voltages, however, elevating cytoplasmic Ca2+ blocks the channel in a voltage-dependent fashion for periods of 2-3 ms. The frequency of these blocking events depends on cytoplasmic Ca2+ and membrane voltage according to second-order kinetics. Alternative cations, such as Mg2+ or Na+, block the yeast plasma-membrane K+ channel in a similar but less pronounced manner.

Item Type: Article
Erschienen: 1992
Creators: Bertl, A. ; Gradmann, D. ; Slayman, C. L.
Type of entry: Bibliographie
Title: Calcium- and voltage-dependent ion channels in Saccharomyces cerevisiae.
Language: English
Date: 1992
Journal or Publication Title: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Volume of the journal: 338
Issue Number: 1283
URL / URN: http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=199...
Abstract:

Ion channels in both the tonoplast and the plasma membrane of Saccharomyces cerevisiae have been characterized at the single channel level by patch-clamp techniques. The predominant tonoplast channel is cation selective, has an open-channel conductance of 120 pS in 100 mM KCl, and conducts Na+ or K+ equally well, and Ca2+ to a lesser extent. Its open probability (Po) is voltage-dependent, peaking at about -80 mV (cytoplasm negative), and falling to near zero at +80 mV. Elevated cytoplasmic Ca2+, alkaline cytoplasmic pH, and reducing agents activate the channel. The predominant plasma membrane channel is highly selective for K+ over anions and other cations, and shows strong outward rectification of the time-averaged current-voltage curves in cell-attached experiments. In isolated inside-out patches with micromolar cytoplasmic Ca2+, this channel is activated by positive going membrane voltages: mean Po is zero at negative membrane voltages and near unity at 100 mV. At moderate positive membrane voltages (20-40 mV), elevating cytoplasmic Ca2+ activates the channel to open in bursts of several hundred milliseconds duration. At higher positive membrane voltages, however, elevating cytoplasmic Ca2+ blocks the channel in a voltage-dependent fashion for periods of 2-3 ms. The frequency of these blocking events depends on cytoplasmic Ca2+ and membrane voltage according to second-order kinetics. Alternative cations, such as Mg2+ or Na+, block the yeast plasma-membrane K+ channel in a similar but less pronounced manner.

Divisions: 10 Department of Biology
?? fb10_botanik ??
10 Department of Biology > Yeast Membrane Biology
Date Deposited: 25 Nov 2010 15:26
Last Modified: 29 Jan 2019 07:57
PPN:
Export:
Suche nach Titel in: TUfind oder in Google
Send an inquiry Send an inquiry

Options (only for editors)
Show editorial Details Show editorial Details