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Updated: Apr 20, 2026
Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Large-scale mutational analysis of Kv11.1 reveals molecular insights into type 2 long QT syndrome
Corey L Anderson1, Catherine E Kuzmicki2, Ryan R Childs2
1Department of Biophysics, University of Wisconsin, Madison, Wisconsin 53705, USA.
Abstract:
It has been suggested that deficient protein trafficking to the cell membrane is the dominant mechanism associated with type 2 Long QT syndrome (LQT2) caused by Kv11.1 potassium channel missense mutations, and that for many mutations the trafficking defect can be corrected pharmacologically. However, this inference was based on expression of a small number of Kv11.1 mutations. We performed a comprehensive analysis of 167 LQT2-linked missense mutations in four Kv11.1 structural domains and found that deficient protein trafficking is the dominant mechanism for all domains except for the distal carboxy-terminus. Also, most pore mutations--in contrast to intracellular domain mutations--were found to have severe dominant-negative effects when co-expressed with wild-type subunits. Finally, pharmacological correction of the trafficking defect in homomeric mutant channels was possible for mutations within all structural domains. However, pharmacological correction is dramatically improved for pore mutants when co-expressed with wild-type subunits to form heteromeric channels.
Insights
Deficient protein trafficking causes Long QT syndrome (LQT2) in most Kv11.1 potassium channel mutations. Pharmacological correction is effective, especially for pore mutations in heteromeric channels.
Area of Science:
- Molecular biology
- Cardiology
- Genetics
Background:
- Type 2 Long QT syndrome (LQT2) is linked to Kv11.1 potassium channel mutations.
- Deficient protein trafficking is a proposed primary mechanism for LQT2.
- Previous studies analyzed limited Kv11.1 mutations.
Purpose of the Study:
- To comprehensively analyze LQT2-linked Kv11.1 missense mutations.
- To determine the dominant mechanism of LQT2 for different mutation locations.
- To assess the potential for pharmacological correction of trafficking defects.
Main Methods:
- Analysis of 167 LQT2-linked Kv11.1 missense mutations across four structural domains.
- Assessment of protein trafficking and dominant-negative effects.
- Evaluation of pharmacological correction in homomeric and heteromeric channel formations.
Main Results:
- Deficient protein trafficking is the dominant mechanism for most Kv11.1 domains, excluding the carboxy-terminus.
- Pore mutations exhibit significant dominant-negative effects, unlike intracellular domain mutations.
- Pharmacological correction is feasible for trafficking defects in all domains, with enhanced efficacy for pore mutants in heteromeric channels.
Conclusions:
- Protein trafficking defects are widespread in LQT2 Kv11.1 mutations.
- Pore mutations pose a distinct challenge due to dominant-negative effects.
- Pharmacological strategies show promise, particularly when considering heteromeric channel function.
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