Mouse ERG K(+) channel clones reveal differences in protein trafficking and function.
J Am Heart Assoc
; 3(6): e001491, 2014 Dec 11.
Article
in En
| MEDLINE
| ID: mdl-25497881
ABSTRACT
BACKGROUND:
The mouse ether-a-go-go-related gene 1a (mERG1a, mKCNH2) encodes mERG K(+) channels in mouse cardiomyocytes. The mERG channels and their human analogue, hERG channels, conduct IKr. Mutations in hERG channels reduce IKr to cause congenital long-QT syndrome type 2, mostly by decreasing surface membrane expression of trafficking-deficient channels. Three cDNA sequences were originally reported for mERG channels that differ by 1 to 4 amino acid residues (mERG-London, mERG-Waterston, and mERG-Nie). We characterized these mERG channels to test the postulation that they would differ in their protein trafficking and biophysical function, based on previous findings in long-QT syndrome type 2. METHODS ANDRESULTS:
The 3 mERG and hERG channels were expressed in HEK293 cells and neonatal mouse cardiomyocytes and were studied using Western blot and whole-cell patch clamp. We then compared our findings with the recent sequencing results in the Welcome Trust Sanger Institute Mouse Genomes Project (WTSIMGP).CONCLUSIONS:
First, the mERG-London channel with amino acid substitutions in regions of highly ordered structure is trafficking deficient and undergoes temperature-dependent and pharmacological correction of its trafficking deficiency. Second, the voltage dependence of channel gating would be different for the 3 mERG channels. Third, compared with the WTSIMGP data set, the mERG-Nie clone is likely to represent the wild-type mouse sequence and physiology. Fourth, the WTSIMGP analysis suggests that substrain-specific sequence differences in mERG are a common finding in mice. These findings with mERG channels support previous findings with hERG channel structure-function analyses in long-QT syndrome type 2, in which sequence changes in regions of highly ordered structure are likely to result in abnormal protein trafficking.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Long QT Syndrome
/
Cloning, Molecular
/
Myocytes, Cardiac
/
Ether-A-Go-Go Potassium Channels
Limits:
Animals
/
Humans
Language:
En
Journal:
J Am Heart Assoc
Year:
2014
Document type:
Article