Uncoupling retro-translocation and degradation in the ER-associated degradation of a soluble protein

Robert J. Lee, Chang Wei Liu, Carol Harty, Ardythe A. McCracken, Martin Latterich, Karin Römisch, George N. DeMartino, Philip J. Thomas, Jeffrey L. Brodsky

Research output: Contribution to journalArticlepeer-review

101 Scopus citations


Aberrant polypeptides in the endoplasmic reticulum (ER) are retro-translocated to the cytoplasm and degraded by the 26S proteasome via ER-associated degradation (ERAD). To begin to resolve the requirements for the retro-translocation and degradation steps during ERAD, a cell-free assay was used to investigate the contributions of specific factors in the yeast cytosol and in ER-derived microsomes during the ERAD of a model, soluble polypeptide. As ERAD was unaffected when cytoplasmic chaperone activity was compromised, we asked whether proteasomes on their own supported both export and degradation in this system. Proficient ERAD was observed if wild-type cytosol was substituted with either purified yeast or mammalian proteasomes. Moreover, addition of only the 19S cap of the proteasome catalyzed ATP-dependent export of the polypeptide substrate, which was degraded upon subsequent addition of the 20S particle.

Original languageEnglish (US)
Pages (from-to)2206-2215
Number of pages10
JournalEMBO Journal
Issue number11
StatePublished - Jun 2 2004


  • Chaperone
  • ERAD
  • Endoplasmic reticulum
  • Proteasome
  • Retro-translocation

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology


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