Seminar by Jost Enninga, Institut Pasteur, Unité « Dynamics of Host-Pathogen Interactions »

Biology Department Seminar of Ecole Polytechnique
Wednesday November 13, 11 am
Conference room – Building 84, 2nd floor – Ecole Polytechnique
Jost Enninga
Institut Pasteur, Unité « Dynamics of Host-Pathogen Interactions »
Université Paris Cité, CNRS UMR3691, Paris, France.
“Combining structural and cell biology approaches
to decipher intracellular niche forma7on of bacterial pathogens”
Abstract
Enteroinvasive pathogens, such as Shigella and Salmonella, induce their uptake into non-phagocy6c epithelial cells
through the injec6on of effectors by the type-3-secre6on system to form a bacterial containing vacuole (BCV).
Salmonella remains mainly localized within the BCV, however Shigella damages the membranes of its BCV to rupture it
and to escape into the host cytosol. We have recently shown via novel 3D imaging techniques based on focused ion
beam scanning EM that interac6ons with in-situ formed macropinosomes in the surrounding of the BCV regulate its
stability. Our workflows correlate highly sensi6ve fluorescence biosensors to pinpoint the successive stages of bacterial
invasion with the power of 3D electron microscopy on the same sample. To obtain structural insights into the underlying
molecular events, we have performed in-situ cryo tomography of frozen lamellae, combined with dynamic op6cal
imaging to iden6fy the molecules that drive these complex interac6ons. This has shown the direct involvement of the
bacterial type-3-secre6on system injuring the host endomembranes to ini6ate vacuolar rupture in a process resembling
mechanopora6on. I will provide an overview on the novel fluorescence and EM technologies for the study of cell
biological processes at the ultrastructural level using bacterial invasion of epithelial cells as model system.
Host : Alexis Gautreau. Let me know if you want to meet him. alexis.gautreau@polytechnique.edu
Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, Institut Polytechnique de Paris, France