Related Experiment Video
Updated: May 14, 2026

Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance
Published on: January 3, 2012
The ERdj5-Sel1L complex facilitates cholera toxin retrotranslocation
Jeffrey M Williams1, Takamasa Inoue, Lindsey Banks
1Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48103, USA.
The ER-resident factor ERdj5 and Sel1L facilitate cholera toxin (CT) retrotranslocation to the cytosol. ERdj5 links to the Hrd1 complex via Sel1L, promoting toxin release for degradation.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Degradation
Background:
- Cholera toxin (CT) enters the endoplasmic reticulum (ER) for retrotranslocation to the cytosol.
- The E3 ubiquitin ligase Hrd1 complex targets CT for retrotranslocation, but the mechanism is unclear.
- ERdj5 is an ER-resident factor involved in protein processing.
Purpose of the Study:
- To elucidate the mechanism by which ERdj5 and the Hrd1 complex facilitate cholera toxin retrotranslocation.
- To identify the roles of ERdj5, Sel1L, and other ER factors in CT transport.
Main Methods:
- Loss-of-function and gain-of-function experiments were used.
- Protein-protein interactions were investigated.
- The role of specific ER factors in CT retrotranslocation was assessed.
Main Results:
- ERdj5, via its J domain, promotes CTA1 retrotranslocation by regulating the binding of CT to the ER Hsp70 chaperone BiP.
- ERdj5 directly interacts with the Hrd1 adaptor Sel1L, linking ERdj5 to the Hrd1 complex.
- Sel1L also binds CT and facilitates its retrotranslocation, while EDEM1 and OS-9 do not play significant roles.
Conclusions:
- ERdj5 and Sel1L are key factors promoting the ER-to-cytosol transport of cholera toxin's CTA1 subunit.
- ERdj5's interaction with Sel1L facilitates CT binding to BiP near the Hrd1 complex, enabling efficient capture for retrotranslocation.
More Related Videos
10:29Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing
Published on: July 6, 2016
12:13TransFLP — A Method to Genetically Modify Vibrio cholerae Based on Natural Transformation and FLP-recombination
Published on: October 8, 2012
Related Concept Videos
Protein Translocation Machinery on the ER Membrane
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Export of Misfolded Proteins out of the ER
Cholera
Insertion of Single-pass Transmembrane Proteins in the RER
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Cotranslational Protein Translocation
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Post-translational Translocation of Proteins to the RER
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...