Correction of defective protein trafficking of a mutant HERG potassium channel in human long QT syndrome. Pharmacological and temperature effects

Zhengfeng Zhou, Qiuming Gong, Craig T. January

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Abstract

The chromosome 7-linked form of congenital long QT syndrome (LQT2) is caused by mutations in the human ether-a-go-go-related gene (HERG) that encodes the rapidly activating delayed rectifier potassium channel. One mechanism for the loss of normal channel function in LQT2 is defective protein trafficking, which results in the failure of the channel protein to reach the plasma membrane. Here we show that the N470D LQT2 mutant protein is trafficking-deficient when expressed at 37 °C in HEK293 cells, whereas at 27 °C its trafficking to the plasma membrane and channel function are markedly improved. We further show that the antiarrhythmic drug E-4031, which selectively blocks HERG channels, also corrects defective protein trafficking of the N470D mutant and can restore the generation of HERG current. Similar findings were obtained with the drugs astemizole and cisapride, as well as with high concentrations of glycerol. The effect of E-4031 on HERG protein trafficking was concentration-dependent and required low drug concentrations (saturation present at 5 μM), developed rapidly with drug exposure, and occurred post-translationally. These findings suggest that protein misfolding leading to defective trafficking of some HERG LQT mutations may be corrected by specific pharmacological strategies.

Original languageEnglish (US)
Pages (from-to)31123-31126
Number of pages4
JournalJournal of Biological Chemistry
Volume274
Issue number44
DOIs
Publication statusPublished - Oct 29 1999
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry

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