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

J Kiehn1, A E Lacerda, A M Brown

  • 1Rammelkamp Center for Research, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio 44109-1998, USA.

The American Journal of Physiology
|July 17, 1999
PubMed

Insights

The human ether-à-go-go-related gene (HERG) channel

Area of Science:

  • Cardiology
  • Molecular Biology
  • Electrophysiology

Background:

  • The rapid, repolarizing potassium current (I(Kr)) in cardiomyocytes is crucial for cardiac action potential.
  • The human ether-à-go-go-related gene (HERG) channel underlies I(Kr), but its single-channel properties remain unclear.

Purpose of the Study:

  • To investigate the single-channel properties of HERG channels.
  • To elucidate the mechanisms of inward rectification in HERG currents.

Main Methods:

  • Heterologous expression of HERG channels in Xenopus oocytes.
  • Single-channel and macropatch current recordings.
  • Kinetic modeling of HERG channel gating.

Main Results:

  • HERG single channels exhibit inward rectification with distinct conductance values at negative and positive potentials.
  • Observed gating patterns include infrequent openings during depolarization and bursts during repolarization.
  • Kinetic modeling supports rapid inactivation from closed states as a key factor in rectification.

Conclusions:

  • Single-channel properties of HERG channels explain the inward rectification of I(Kr).
  • Gating kinetics, particularly rapid inactivation, are critical for HERG channel function and cardiac repolarization.

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