Abstract
Mutations in the human ether-a-go-go-related gene (HERG) cause long QT syndrome. We previously showed that the HERG N470D mutation expressed as homotetrameric channels causes a protein trafficking defect, and this can be corrected by the HERG channel blocking drug E-4031. The N470D mutant also has been reported to cause dominant negative suppression of HERG current when coexpressed with wild-type channel subunits. The aims of this study were 1) to investigate the molecular mechanism responsible for the dominant negative effect of the N470D mutant coexpressed with wild-type subunits and 2) to test whether the trafficking defective heteromeric channels could be pharmacologically rescued by E-4031. Using a combination of immunoprecipitation and Western blot methods, we showed that N470D mutant and wild-type HERG subunits were physically associated in the endoplasmic reticulum as heteromeric channels. The coassembly resulted in the retention of both wild-type and N470D subunits in the endoplasmic reticulum. Culturing cells in E-4031 increased the cell surface expression of these channels, although with an altered electrophysiological phenotype. These results suggest that the dominant negative effect of the N470D wild-type coassembled channels is caused by retention of heteromeric channels in the endoplasmic reticulum and that the trafficking defect of these channels can be corrected by specific pharmacological strategies.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 287 |
| Issue number | 2 56-2 |
| DOIs | |
| State | Published - Aug 2004 |
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Keywords
- Arrhythmia
- Ion channels
- Patch clamp
- Protein trafficking
ASJC Scopus subject areas
- Physiology
Cite this
Pharmacological rescue of trafficking defective HERG channels formed by coassembly of wild-type and long QT mutant N470D subunits. / Gong, Qiuming; Anderson, Corey L.; January, Craig T.; Zhou, Zhengfeng.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 287, No. 2 56-2, 08.2004.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pharmacological rescue of trafficking defective HERG channels formed by coassembly of wild-type and long QT mutant N470D subunits
AU - Gong, Qiuming
AU - Anderson, Corey L.
AU - January, Craig T.
AU - Zhou, Zhengfeng
PY - 2004/8
Y1 - 2004/8
N2 - Mutations in the human ether-a-go-go-related gene (HERG) cause long QT syndrome. We previously showed that the HERG N470D mutation expressed as homotetrameric channels causes a protein trafficking defect, and this can be corrected by the HERG channel blocking drug E-4031. The N470D mutant also has been reported to cause dominant negative suppression of HERG current when coexpressed with wild-type channel subunits. The aims of this study were 1) to investigate the molecular mechanism responsible for the dominant negative effect of the N470D mutant coexpressed with wild-type subunits and 2) to test whether the trafficking defective heteromeric channels could be pharmacologically rescued by E-4031. Using a combination of immunoprecipitation and Western blot methods, we showed that N470D mutant and wild-type HERG subunits were physically associated in the endoplasmic reticulum as heteromeric channels. The coassembly resulted in the retention of both wild-type and N470D subunits in the endoplasmic reticulum. Culturing cells in E-4031 increased the cell surface expression of these channels, although with an altered electrophysiological phenotype. These results suggest that the dominant negative effect of the N470D wild-type coassembled channels is caused by retention of heteromeric channels in the endoplasmic reticulum and that the trafficking defect of these channels can be corrected by specific pharmacological strategies.
AB - Mutations in the human ether-a-go-go-related gene (HERG) cause long QT syndrome. We previously showed that the HERG N470D mutation expressed as homotetrameric channels causes a protein trafficking defect, and this can be corrected by the HERG channel blocking drug E-4031. The N470D mutant also has been reported to cause dominant negative suppression of HERG current when coexpressed with wild-type channel subunits. The aims of this study were 1) to investigate the molecular mechanism responsible for the dominant negative effect of the N470D mutant coexpressed with wild-type subunits and 2) to test whether the trafficking defective heteromeric channels could be pharmacologically rescued by E-4031. Using a combination of immunoprecipitation and Western blot methods, we showed that N470D mutant and wild-type HERG subunits were physically associated in the endoplasmic reticulum as heteromeric channels. The coassembly resulted in the retention of both wild-type and N470D subunits in the endoplasmic reticulum. Culturing cells in E-4031 increased the cell surface expression of these channels, although with an altered electrophysiological phenotype. These results suggest that the dominant negative effect of the N470D wild-type coassembled channels is caused by retention of heteromeric channels in the endoplasmic reticulum and that the trafficking defect of these channels can be corrected by specific pharmacological strategies.
KW - Arrhythmia
KW - Ion channels
KW - Patch clamp
KW - Protein trafficking
UR - http://www.scopus.com/inward/record.url?scp=3242717751&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=3242717751&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00052.2004
DO - 10.1152/ajpheart.00052.2004
M3 - Article
VL - 287
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 2 56-2
ER -