Related Experiment Video
Updated: Jun 25, 2026

Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Selective binding of virulence type III export chaperones by FliJ escort orthologues InvI and YscO
Lewis D B Evans1, Colin Hughes
1Department of Pathology, Cambridge University, Cambridge, UK. le227@cam.ac.uk
Abstract:
Bacteria secrete flagella subunits and deliver virulence effectors via type III export systems. During flagellar filament assembly, a chaperone escort mechanism has been proposed to enhance the export of early, minor flagellar filament components by selectively binding and cycling their chaperones. Here we identify virulence orthologues of the flagellar chaperone escort FliJ and show that the orthologues Salmonella InvI and Yersinia YscO are, like FliJ, essential for their type III export pathway and similarly, do not bind export substrates. Like FliJ, they recognize a subset of export chaperones, in particular those of the host membrane translocon components required for subsequent effector delivery.
Related Concept Videos
Regulation of Bacterial Virulence
Bacterial Translocation and Protein Secretion
Determinants of Bacterial Pathogenicity and Virulence
Clathrin Coated Vesicles
Gram-negative Bacterial Protein Secretion Systems
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.

