Abstract
Introduction: Genetic mutations in KCNH2, which encodes hERG, the alpha subunit of the potassium channel responsible for the IKr current, cause long QT syndrome (LQTS), an inherited cardiac arrhythmia disorder. Electrophysiology techniques are used to correlate genotype with molecular phenotype to determine which mutations identified in patients diagnosed with LQTS are disease causing, and which are benign. These investigations are usually done using heterologous expression in cell lines, and often, epitope fusion tags are used to enable isolation and identification of the protein of interest. Methods and results: Here, we demonstrate through electrophysiology techniques and immunohistochemistry, that both N-terminal and C-terminal myc fusion tags may perturb hERG protein channel expression and kinetics of the IKr current. We also characterize the impact of 2 previously reported inadvertent cDNA variants on hERG channel expression and half-life. Conclusion: Our results underscore the importance of careful characterization of the impact of epitope fusion tags and of confirming complete sequence accuracy prior to genotype-phenotype studies for ion channel proteins such as hERG.
Original language | English (US) |
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Pages (from-to) | 1070-1082 |
Number of pages | 13 |
Journal | Journal of cardiovascular electrophysiology |
Volume | 28 |
Issue number | 9 |
DOIs | |
State | Published - Sep 2017 |
Keywords
- KCNH2
- electrophysiology
- epitope tag
- hERG
- long QT syndrome
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)