Isoform-specific dominant-negative effects associated with hERG1 G628S mutation in long QT syndrome

Matthew R. Stump, Qiuming Gong, Zhengfeng Zhou

    Research output: Contribution to journalArticlepeer-review

    8 Scopus citations

    Abstract

    Background: Mutations in the human ether-a-go-go-related gene 1 (hERG1) cause type 2 long QT syndrome (LQT2). The hERG1 gene encodes a K+ channel with properties similar to the rapidly activating delayed rectifying K+ current in the heart. Several hERG1 isoforms with unique structural and functional properties have been identified. To date, the pathogenic mechanisms of LQT2 mutations have been predominantly described in the context of the hERG1a isoform. In the present study, we investigated the functional consequences of the LQT2 mutation G628S in the hERG1b and hERG1aUSO isoforms. Methods: A double-stable, mammalian expression system was developed to characterize isoform-specific dominant-negative effects of G628S-containing channels when co-expressed at equivalent levels with wild-type hERG1a. Western blot and co-immunoprecipitation studies were performed to study the trafficking and co-assembly of wild-type and mutant hERG1 isoforms. Patch-clamp electrophysiology was performed to characterize hERG1 channel function and the isoform-specific dominant-negative effects associated with the G628S mutation. Conclusions: The non-functional hERG1a-G628S and hERG1b-G628S channels co-assembled with wild-type hERG1a and dominantly suppressed hERG1 current. In contrast, G628S-induced dominant-negative effects were absent in the context of the hERG1aUSO isoform. hERG1aUSO-G628S channels did not appreciably associate with hERG1a and did not significantly suppress hERG1 current when co-expressed at equivalent ratios or at ratios that approximate those found in cardiac tissue. These results suggest that the dominant-negative effects of LQT2 mutations may primarily occur in the context of the hERG1a and hERG1b isoforms.

    Original languageEnglish (US)
    Article numbere42552
    JournalPloS one
    Volume7
    Issue number8
    DOIs
    StatePublished - Aug 2 2012

    ASJC Scopus subject areas

    • Biochemistry, Genetics and Molecular Biology(all)
    • Agricultural and Biological Sciences(all)
    • General

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