Organization
Prof. Bernard C. Rossier
rossier@jeantet.ch

Secretariat:
Ms Marie-Madeleine
Cuenat
+41 22 704 36 41
cuenat@jeantet.ch

Webmaster: morard@jeantet.ch

Louis-Jeantet
Foundation
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P.O. Box 270
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Switerland
Phone
+41 22 704 36 36
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Pascale Cossart

Institut Pasteur, Paris (France)

2008 Louis-Jeantet prize-winner

Tuesday, October 23, 18:00 - 19:00

Keynote Lecture

New concepts in host-pathogen interactions:

lessons from Listeria

Pathogens have long co-evolved with their host and devised elegant and efficient strategies to exploit to their own profit molecules or mechanisms critical to the host. The study of these strategies has led to the discovery of amazing tricks used by pathogens during infection and also to that of unsuspected mechanisms normally present in the cell. Pathogens thus appear as powerful tools to address critical issues in Cell Biology. We will illustrate this duality by presenting several aspects of the infection by Listeria monocytogenes, a food-borne bacterium able to invade mammalian cells and spread directly from cell to cell. Other bacteria will also be discussed.

We will first show how Listeria orchestrates its entry into cells, and will present the discovery of an unsuspected role for clathrin in the early cytoskeleton rearrangments leading to internalization. We will also discuss how septins are increasingly recognized as important components of the cytoskeleton which also control the Listeria entry process. Interestingly, septins are able to entrap cytosolic bacteria able to move from cell to cell such as Shigella -but not Listeria- in a process tightly coupled to autophagy and which limits their actin-based dissemination.

Finally, we recently discovered that Listeria can reprogramme the host transcription by injecting into the cell nucleus a protein that interacts with a previously unknown heterochromatinisation factor and prevents its action raising the possibility that chromatin marks could remain after infection. A new field of investigation, i.e. chromatin remodelling by pathogens and a new discipline "pathoepigenetics" are emerging.

 

Biography

After studying chemistry, Pascale Cossart obtained a master degree at Georgetown University, and a PhD at the Institut Pasteur. In 1986, she started her work on Listeria. She is Professor and Head of the Unit "Interactions Bactéries-Cellules" at the Institut Pasteur. She was an HHMI international scholar until 2010. She received the L’Oréal/UNESCO Prize (1998), the Robert Koch Prize (2007), the Louis-Jeantet Prize for Medicine (2008). She is a member of EMBO (1995), of the French Académie des Sciences (2002), of  the "Leopoldina" (2001). She is a foreign member of the American National Academy of Sciences (2009) and of the Royal Society (2010).

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