» Articles » PMID: 650672

Voltage-gated Cation Conductance Channel from Fragmented Sarcoplasmic Reticulum: Steady-state Electrical Properties

Overview
Journal J Membr Biol
Date 1978 Apr 20
PMID 650672
Citations 85
Authors
Affiliations
Soon will be listed here.
Abstract

The interaction of fragmented sarcoplasmic reticulum (SR) with an artificial planar phospholipid membrane under conditions known to induce fusion of phospholipid vesicles raises the conductance of the planar bilayer by several orders of magnitude. Measurements of steady-state electrical properties of bilayers thus modified by SR show that two types of conductance pathways are present. One is a voltage-independent pathway which may be somewhat anion-selective. The other is a voltage-gated ionophore showing selectivity to small monovalent cations. This latter ionophore is fully oriented within the artificial bilayer and is inhibited asymmetrically by divalent cations. It is also inhibited below pH6. The ionophore displays single-channel conductance fluctuations between two states. "open" and "closed", with an open-state conductance of 1.4 x 10-10 mho in 0.1 M K+. The physiological function of this ionophore is unknown.

Citing Articles

Kir2.1 dysfunction at the sarcolemma and the sarcoplasmic reticulum causes arrhythmias in a mouse model of Andersen-Tawil syndrome type 1.

Macias A, Gonzalez-Guerra A, Moreno-Manuel A, Cruz F, Gutierrez L, Garcia-Quintans N Nat Cardiovasc Res. 2024; 1(10):900-917.

PMID: 39195979 PMC: 11358039. DOI: 10.1038/s44161-022-00145-2.


The biophysical properties of TRIC-A and TRIC-B and their interactions with RyR2.

Hu J, Venturi E, Sigalas C, Murayama T, Nishi M, Takeshima H J Gen Physiol. 2023; 155(11).

PMID: 37756589 PMC: 10522464. DOI: 10.1085/jgp.202113070.


Disruption of ER ion homeostasis maintained by an ER anion channel CLCC1 contributes to ALS-like pathologies.

Guo L, Mao Q, He J, Liu X, Piao X, Luo L Cell Res. 2023; 33(7):497-515.

PMID: 37142673 PMC: 10313822. DOI: 10.1038/s41422-023-00798-z.


Electrical signals in the ER are cell type and stimulus specific with extreme spatial compartmentalization in neurons.

Campbell E, Abushawish A, Valdez L, Bell M, Haryono M, Rangamani P Cell Rep. 2023; 42(1):111943.

PMID: 36640310 PMC: 10033362. DOI: 10.1016/j.celrep.2022.111943.


Enhanced activity of multiple TRIC-B channels: an endoplasmic reticulum/sarcoplasmic reticulum mechanism to boost counterion currents.

OBrien F, Eberhardt D, Witschas K, El-Ajouz S, Iida T, Nishi M J Physiol. 2019; 597(10):2691-2705.

PMID: 30907436 PMC: 6567852. DOI: 10.1113/JP277241.


References
1.
HLADKY S, Haydon D . Discreteness of conductance change in bimolecular lipid membranes in the presence of certain antibiotics. Nature. 1970; 225(5231):451-3. DOI: 10.1038/225451a0. View

2.
Gordon L, Haydon D . Kinetics and stability of alamethicin conducting channels in lipid bilayers. Biochim Biophys Acta. 1976; 436(3):541-56. DOI: 10.1016/0005-2736(76)90439-9. View

3.
Gordon L, Haydon D . The unit conductance channel of alamethicin. Biochim Biophys Acta. 1972; 255(3):1014-8. DOI: 10.1016/0005-2736(72)90415-4. View

4.
Miller C, RACKER E . Ca++-induced fusion of fragmented sarcoplasmic reticulum with artificial planar bilayers. J Membr Biol. 1976; 30(3):283-300. DOI: 10.1007/BF01869673. View

5.
Meissner G . Isolation and characterization of two types of sarcoplasmic reticulum vesicles. Biochim Biophys Acta. 1975; 389(1):51-68. DOI: 10.1016/0005-2736(75)90385-5. View