Related Experiment Video
Updated: Dec 21, 2025

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions
Published on: September 9, 2014
Actin Assembly around the Shigella-Containing Vacuole Promotes Successful Infection
Sonja Kühn1, John Bergqvist1, Magdalena Gil1
1Institut Pasteur, Department of Cell Biology and Infection, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, 75015 Paris, France; CNRS UMR3691, 25 Rue du Dr. Roux, 75015 Paris, France.
Abstract:
The enteroinvasive bacterium Shigella flexneri forces its uptake into non-phagocytic host cells through the translocation of T3SS effectors that subvert the actin cytoskeleton. Here, we report de novo actin polymerization after cellular entry around the bacterium-containing vacuole (BCV) leading to the formation of a dynamic actin cocoon. This cocoon is thicker than any described cellular actin structure and functions as a gatekeeper for the cytosolic access of the pathogen. Host CDC42, TOCA-1, N-WASP, WIP, the Arp2/3 complex, cortactin, coronin, and cofilin are recruited to the actin cocoon. They are subverted by T3SS effectors, such as IpgD, IpgB1, and IcsB. IcsB immobilizes components of the actin polymerization machinery at the BCV dependent on its fatty acyltransferase activity. This represents a unique microbial subversion strategy through localized entrapment of host actin regulators causing massive actin assembly. We propose that the cocoon promotes subsequent invasion steps for successful Shigella infection.
Related Concept Videos
Intracellular Movement of Viruses and Bacteria
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Intralumenal Vesicles and Multivesicular Bodies
Cancer Cell Migration through Invadopodia
Actin Polymerization and Cell Motility
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate....

