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Updated: May 11, 2026

Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells
15:28

Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells

Published on: October 1, 2010

Trafficking defects in PAS domain mutant Kv11.1 channels: roles of reduced domain stability and altered domain-domain

Ying Ke1, Chai Ann Ng, Mark J Hunter

  • 1Mark Cowley Lidwill Research Program in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.

The Biochemical Journal
|June 1, 2013
PubMed

Insights

Mutations in the Kv11.1 potassium channel

Area of Science:

  • Cardiovascular Physiology
  • Molecular Biology
  • Genetics

Background:

  • Long-QT syndrome type 2 (LQTS2) is a primary cause of sudden cardiac death in young individuals.
  • Loss of Kv11.1 potassium channel function underlies LQTS2 pathology.
  • The cytosolic Per/Arnt/Sim (PAS) domain of Kv11.1 is a known mutation hotspot linked to trafficking defects.

Purpose of the Study:

  • To investigate the molecular basis of Kv11.1 PAS domain mutations causing trafficking defects.
  • To quantify the impact of PAS domain mutants on channel folding and interactions.

Main Methods:

  • Thermostability assays of isolated PAS domains with various mutants.
  • Co-immunoprecipitation assays to assess binding between isolated PAS domains and truncated hERG channels.
  • Analysis of mutant effects on PAS domain folding and inter-domain interactions.

Main Results:

  • Most PAS domain mutants impaired the thermostability of the isolated domain.
  • Six surface mutants near a hydrophobic patch disrupted PAS domain binding to the hERG channel.
  • Four surface mutants and one buried mutant did not affect PAS domain binding to the hERG channel.

Conclusions:

  • Interactions between the Kv11.1 PAS domain and the rest of the channel are crucial for hERG assembly.
  • Mutations affecting PAS domain interactions lead to more severe trafficking defects than those solely impacting domain unfolding.

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