Novel Brugada syndrome-causing mutation in ion-conducting pore of cardiac Na+ channel does not affect ion selectivity properties.

Details

Serval ID
serval:BIB_BA2C52D2F2C1
Type
Article: article from journal or magazin.
Collection
Publications
Title
Novel Brugada syndrome-causing mutation in ion-conducting pore of cardiac Na+ channel does not affect ion selectivity properties.
Journal
Acta physiologica Scandinavica
Author(s)
Amin A.S., Verkerk A.O., Bhuiyan Z.A., Wilde A.A., Tan H.L.
ISSN
0001-6772 (Print)
ISSN-L
0001-6772
Publication state
Published
Issued date
12/2005
Peer-reviewed
Oui
Volume
185
Number
4
Pages
291-301
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
Brugada syndrome is an inherited cardiac disease with an increased risk of sudden cardiac death. Thus far Brugada syndrome has been linked only to mutations in SCN5A, the gene encoding the alpha-subunit of cardiac Na+ channel. In this study, a novel SCN5A gene mutation (D1714G) is reported, which has been found in a 57-year-old male patient. Since the mutation is located in a segment of the ion-conducting pore of the cardiac Na+ channel, which putatively determines ion selectivity, it may affect ion selectivity properties.
HEK-293 cells were transfected with wild-type (WT) or D1714G alpha-subunit and beta-subunit cDNA. Whole-cell configuration of the patch-clamp technique was used to study biophysical properties at room temperature (21 degrees C) and physiological temperature (36 degrees C). This study represents the first measurements of human Na+ channel kinetics at 36 degrees C. Ion selectivity, current density, and gating properties of WT and D1714G channel were studied.
D1714G channel yielded nearly 80% reduction of Na+ current density at 21 and 36 degrees C. At both temperatures, no significant changes were observed in V(1/2) values and slope factors for voltage-dependent activation and inactivation. At 36 degrees C, but not at 21 degrees C, D1714G channel exhibited more slow inactivation compared with WT channel. Ion selectivity properties were not affected by the mutation at both temperatures, as assessed by either current or permeability ratio.
This study shows no changes in ion selectivity properties of D1714G channel. However, the profoundly decreased current density associated with the D1714G mutation may explain the Brugada syndrome phenotype in our patient.

Keywords
Animals, Arrhythmias, Cardiac/genetics, Cell Line, Cricetinae, Death, Sudden, Cardiac/etiology, Humans, Ion Channel Gating/genetics, Male, Middle Aged, Mutation, Missense, Patch-Clamp Techniques, Sodium Channels/genetics, Sodium Channels/metabolism, Syndrome, Transfection/methods
Pubmed
Web of science
Create date
01/03/2018 15:38
Last modification date
20/08/2019 15:28
Usage data