Addition of membrane vesicles prepared from transverse tubule (T-tubule) membranes of rabbit skeletal muscle to the aqueous phase of a planar lipid bilayer induces a stepwise increase in conductance. This conductance is both voltage and Ca2+ dependent. At 1 mM Ca2+, the steady-state conductance is maximal at voltages higher than +20 mV and decreases for more negative voltages. (Voltages refer to the side to which the vesicles are added, cis) Decreasing the Ca2+ concentration reversibly shifts the conductance-voltage curve toward the right along the voltage axis. Furthermore, Ca2+ can activate the conductance only if added to the cis compartment. Neither Mg2+, Ba2+, nor Cd2+ can activate the conductance induced by T-tubule vesicles. Addition of 5 mM tetraethylammonium ion to the trans, but not the cis, side abolishes the T-tubule-induced conductance. The Ca2+-dependent conductance appears as a consequence of ionic channel formation. Single-channel activity appears in bursts followed by periods of time in which the channel remains "silent". The conductance of the open channel averages 226 pS in 0.1 M KC1 and is voltage and Ca2+ independent. However, the fraction of time that the channel remains in the open state is voltage and Ca2+ dependent in a manner that parallels the voltage and Ca2+ dependence of the multichannel membrane. The channel is 6.6 times more permeable to K+ than to Na+ and is impermeable to C1-.
%0 Journal Article
%1 Latorre:1982p5158
%A Latorre, R
%A Vergara, C
%A Hidalgo, C
%D 1982
%J Proc Natl Acad Sci USA
%K Animals, Bilayers, Calcium, Cations: Cell Cell-Free Channels, Conductivity, Divalent, Electric Ion Lipid Membrane Membrane, Potassium, Potentials, Rabbits, Sarcolemma System,
%N 3
%P 805--9
%T Reconstitution in planar lipid bilayers of a Ca2+-dependent K+ channel from transverse tubule membranes isolated from rabbit skeletal muscle
%U http://www.pnas.org/cgi/reprint/79/3/805
%V 79
%X Addition of membrane vesicles prepared from transverse tubule (T-tubule) membranes of rabbit skeletal muscle to the aqueous phase of a planar lipid bilayer induces a stepwise increase in conductance. This conductance is both voltage and Ca2+ dependent. At 1 mM Ca2+, the steady-state conductance is maximal at voltages higher than +20 mV and decreases for more negative voltages. (Voltages refer to the side to which the vesicles are added, cis) Decreasing the Ca2+ concentration reversibly shifts the conductance-voltage curve toward the right along the voltage axis. Furthermore, Ca2+ can activate the conductance only if added to the cis compartment. Neither Mg2+, Ba2+, nor Cd2+ can activate the conductance induced by T-tubule vesicles. Addition of 5 mM tetraethylammonium ion to the trans, but not the cis, side abolishes the T-tubule-induced conductance. The Ca2+-dependent conductance appears as a consequence of ionic channel formation. Single-channel activity appears in bursts followed by periods of time in which the channel remains "silent". The conductance of the open channel averages 226 pS in 0.1 M KC1 and is voltage and Ca2+ independent. However, the fraction of time that the channel remains in the open state is voltage and Ca2+ dependent in a manner that parallels the voltage and Ca2+ dependence of the multichannel membrane. The channel is 6.6 times more permeable to K+ than to Na+ and is impermeable to C1-.
@article{Latorre:1982p5158,
abstract = {Addition of membrane vesicles prepared from transverse tubule (T-tubule) membranes of rabbit skeletal muscle to the aqueous phase of a planar lipid bilayer induces a stepwise increase in conductance. This conductance is both voltage and Ca2+ dependent. At 1 mM Ca2+, the steady-state conductance is maximal at voltages higher than +20 mV and decreases for more negative voltages. (Voltages refer to the side to which the vesicles are added, cis) Decreasing the Ca2+ concentration reversibly shifts the conductance-voltage curve toward the right along the voltage axis. Furthermore, Ca2+ can activate the conductance only if added to the cis compartment. Neither Mg2+, Ba2+, nor Cd2+ can activate the conductance induced by T-tubule vesicles. Addition of 5 mM tetraethylammonium ion to the trans, but not the cis, side abolishes the T-tubule-induced conductance. The Ca2+-dependent conductance appears as a consequence of ionic channel formation. Single-channel activity appears in bursts followed by periods of time in which the channel remains "silent". The conductance of the open channel averages 226 pS in 0.1 M KC1 and is voltage and Ca2+ independent. However, the fraction of time that the channel remains in the open state is voltage and Ca2+ dependent in a manner that parallels the voltage and Ca2+ dependence of the multichannel membrane. The channel is 6.6 times more permeable to K+ than to Na+ and is impermeable to C1-.},
added-at = {2009-11-12T16:21:13.000+0100},
author = {Latorre, R and Vergara, C and Hidalgo, C},
biburl = {https://www.bibsonomy.org/bibtex/21cd261eec7a5d4091b8e5012834f9098/fdiehl},
date-added = {2008-02-11 14:47:15 +0100},
date-modified = {2009-11-10 09:46:31 +0100},
description = {bib-komplett},
interhash = {25765d75dc20f48ccd590391c256ec15},
intrahash = {1cd261eec7a5d4091b8e5012834f9098},
journal = {Proc Natl Acad Sci USA},
keywords = {Animals, Bilayers, Calcium, Cations: Cell Cell-Free Channels, Conductivity, Divalent, Electric Ion Lipid Membrane Membrane, Potassium, Potentials, Rabbits, Sarcolemma System,},
language = {eng},
local-url = {file://localhost/Neurobio/Papers/6278496.pdf},
month = Feb,
number = 3,
pages = {805--9},
pmid = {6278496},
rating = {0},
timestamp = {2009-11-12T16:21:20.000+0100},
title = {Reconstitution in planar lipid bilayers of a Ca2+-dependent K+ channel from transverse tubule membranes isolated from rabbit skeletal muscle},
uri = {papers://7B65697B-E216-4648-8A41-C67830C0DC73/Paper/p5158},
url = {http://www.pnas.org/cgi/reprint/79/3/805},
volume = 79,
year = 1982
}