Ufd1-Npl4 is a negative regulator of cholera toxin retrotranslocation

Elizabeth McConnell, Agnieszka Lass, Cezary Wójcik

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The A1 chain of the cholera toxin (CT) undergoes retrotranslocation to the cytosol across the endoplasmic reticulum (ER) membrane by hijacking ER-associated degradation (ERAD). In the cytosol the CT A1 chain stimulates adenylyl cyclase. The VCPUfd1-Npl4 complex mediates retrotranslocation of emerging ER proteins. While one group reported that VCP is required for CT retrotranslocation, another group concluded the opposite. We show that VCP is dispensable for CT retrotranslocation, however RNAi of either Ufd1 or Npl4 induces an increase in adenylyl cyclase activity induced by CT. RNAi of VCP, Ufd1 or Npl4 did not affect adenylyl cyclase activity induced by forskolin. These findings are coherent with our previous report showing that depletion of Ufd1-Npl4 accelerates ERAD of reporter substrates. To integrate contradictory results we propose a new model, where Ufd1-Npl4 is a negative regulator of retrotranslocation, delaying the retrotranslocation of ERAD substrates independently of its association with VCP.

Original languageEnglish (US)
Pages (from-to)1087-1090
Number of pages4
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - Apr 20 2007
Externally publishedYes


  • Adenylyl cyclase
  • Cholera toxin
  • ER-associated degradation (ERAD)
  • Forskolin
  • Retrotranslocation
  • Valosin-containing protein (VCP)

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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