The Pasteur Museum is housed in the apartment where Louis Pasteur spent his final seven years and offers a rare behind-the-scenes look at the living and working environment of the world-renowned scientist. Visitors can gain a unique insight into his everyday life alongside his ...
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Ever since the introduction of the world’s first "Technical Microbiology" course in 1889, teaching has been a priority for the Institut Pasteur. The Institut Pasteur has an international reputation for quality teaching that attracts students from all over ...
The mission of the Industrial Partnership team is to detect, promote, assist and protect the inventive activities from research (inventions, know-how and biological materials) conducted at the Institut Pasteur (and in some Institutes of its international network), and transfer there to industrial ...
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The RickA Protein of Rickettsia conorii is a novel activator of Arp2/3 complex
Vérinique Villiers and Edith Gouin work together on the Rickettsia project. Listeria monocytogenes, Shigella flexneri, and Rickettisia conorii are three bacterial pathogens that are able to polymerize actin into ’comet tail’ structures and move within the cytosol of infected cells. The actin-based motilities of L. monocytogenes and S. flexneri are known to require the bacterial proteins ActA and IscA, respectively, and several mammalian cytoskeleton proteins including Arp2/3 complex and VASP (vasodilator-stimulated phosphoprotein) for L. monotyogenes and vinculin and N-WASP (the neural Wiskott-Aldrich syndrome protein) for S. flexneri.
We have previously reported that the actin tails of Rickettsia conorii, another intracellular bacterium, unlike those of Listeria of Shigella are composed of long unbranched actin filaments apparently devoid of Arp2/3 complex (J. Cell. Science, 1999).
Then, we identified a R. conorii surface protein, RickA, as a novel type of Arp2/3 activator. In vitro, RickA activates, albeit far less efficiently than ActA, the nucleating activity of Arp2/3 and its capacity to induce branch formation. In infected cells, Arp2/3 is detected on the bacterial surface but not in the Rickettsia tails, as it is the case for Listeria and Shigella tails. When expressed in mammalian cells, and targeted to the membrane, RickA induces filopodia. Thus RickA-induced actin polymerisation, which results in the generation of the long actin filaments reminiscent of those present in filopodia, appears as a powerful tool for the study of filopodia formation.
The Rickettsia actin tails consist of long filaments. Electron microscopy of myosin S1 decorated actin tails of R. conorii and L. monocytogenes.
Updated on 12/05/2014
Unité Interactions Bactéries-Cellules
INSERM U604 INRA USC2020
25, Rue du Docteur Roux
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The metro stations Pasteur (line 6) and Volontaires (line 12) are within a 5 min walking distance from the Pasteur Institute.
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