Involvement of caveolin in low K+-induced endocytic degradation of cell-surface human ether-a-go-go-related gene (hERG) channels

Hamid Massaeli, Tao Sun, Xian Li, Heidi Shallow, Jimmy Wu, Jianmin Xu, Wentao Li, Christian Hanson, Jun Guo, Shetuan Zhang

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Reduction in the rapidly activating delayed rectifier K+ channel current (IKr) due to either mutations in the human ether-a-go-go-related gene (hERG) or drug block causes inherited or drug-induced long QT syndrome. A reduction in extracellular K+ concentration ([K+]o) exacerbates long QT syndrome. Recently, we demonstrated that lowering [K+]o promotes degradation of IKr in rabbit ventricular myocytes and of the hERG channel stably expressed in HEK 293 cells. In this study, we investigated the degradation pathways of hERG channels under low K+ conditions. We demonstrate that under low K+ conditions, mature hERG channels and caveolin-1 (Cav1) displayed a parallel time-dependent reduction. Mature hERG channels coprecipitated with Cav1 in co-immunoprecipitation analysis, and internalized hERG channels colocalized with Cav1 in immunocytochemistry analysis. Overexpression of Cav1 accelerated internalization of mature hERG channels in 0 mM K+o, whereas knockdown of Cav1 impeded this process. In addition, knockdown of dynamin 2 using siRNA transfection significantly impeded hERG internalization and degradation under low K+o conditions. In cultured neonatal rat ventricular myocytes, knockdown of caveolin-3 significantly impeded low K+o-induced reduction of IKr. Our data indicate that a caveolin-dependent endocytic route is involved in low K+o-induced degradation of mature hERG channels.

Original languageEnglish
Pages (from-to)27259-27264
Number of pages6
JournalJournal of Biological Chemistry
Volume285
Issue number35
DOIs
Publication statusPublished - 27 Aug 2010

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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