Transient calnexin interaction confers long-term stability on folded K+ channel protein in the ER

Rajesh Khanna, Eun Jeon Lee, Diane M. Papazian

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We recently showed that an unglycosylated form of the Shaker potassium channel protein is retained in the endoplasmic reticulum (ER) and degraded by proteasomes in mammalian cells despite apparently normal folding and assembly. These results suggest that channel proteins with a native structure can be substrates for ER-associated degradation. We have now tested this hypothesis using the wild-type Shaker protein. Wild-type Shaker is degraded by cytoplasmic proteasomes when it is trapped in the ER and prevented from interacting with calnexin. Neither condition alone is sufficient to destabilize the protein. Proteasomal degradation of the wild-type protein is abolished when ER mannosidase I trimming of the core glycan is inhibited. Our results indicate that transient interaction with calnexin provides long-term protection from ER-associated degradation.

Original languageEnglish (US)
Pages (from-to)2897-2908
Number of pages12
JournalJournal of Cell Science
Issue number14
StatePublished - Jun 15 2004
Externally publishedYes


  • Calnexin
  • ER glucosidase/mannosidase
  • ERAD
  • Glycan trimming
  • Glycosylation
  • Potassium channels
  • Proteasome
  • Shaker
  • Voltage-dependent

ASJC Scopus subject areas

  • Cell Biology


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