Intracellular motility



[Photo: H. Bierne, in Cellular Microbiology, American Society for Microbiology]

Mammalian cells infected by Listeria monocytogenes (red) in the process of polymerizing actin (green).






[Jasnin et al., PNAS 2013]


Hollow Listeria cytoplasmic comet tail contains closely packed parallel filaments. a) Slice through the tomogram of a cytoplasmic comet tail (tail) in a PtK2 cell (cytoplasm is indicated by cyt) infected by Listeria. b) (Scale bar: 200 nm.) Distribution of XY-filaments (b) and Z-filaments (c) in the XZ plane, projected over the Y axis. The color scale ranges from high occurrence (red) to low occurrence (blue) (same color code in all relevant panels). f) XY-filaments projected into the XY plane. The color of the filaments corresponds to their anglewith respect to the Y axis: 0–15° (blue), 15– 30° (green), 30–45° (red). The cell wall of the bacterium is shown in gray.



[Cossart et al., Microbes and infection 2008]

Actin-based motility. a) Cell infected with Listeria and observed by immunofluorescence (green: actin; red: bacteria; blue: nucleus). b) Schematic representation of actin polymerization by various pathogens.





[Pizarro-Cerda et al., Journal of Pathology 2006]

Polymerization of actin comet tails by ActA. a) The proline-rich sequence of ActA recruits VASP, which in turn

recruits profilin and actin monomers that will be polymerized by the Arp2/3 complex, leading to the formation of actin comet tails that power the movement of L. monocytogenes in the host cell cytoplasm. b) Immunofluorescence showing the actin cytoskeleton (green) of kangaroo PTK2 and the polymerization of actin comet tails by L. monocytogenes (red).





[Cossart et al., Current Opinion in Immunology 2001]

Model of actin assembly induced by ActA. The ActA is represented as a dimer and its polar distribution at the bacterial surface is represented as a hatched area. The bacterium is moving from left to right as indicated by the arrow.






[Gouin et al., Journal of Cell Science 1999]

Electron microscopy of myosin S1 decorated actin tails of R. conorii a), L. monocytogenes b) and S. flexneri e) in HEp2 cells. The two boxes in b and e are shown at higher magnification in c and d, and in f and g, respectively. Bars: a,b) 0.2 µm; e) 0.4 µm; c,d,f,g) 50 nm.





[Gouin et al., Journal of Cell Science 1999]

Electron microscopy of S1 myosin decorated actin tails of R. conorii a,b), L. monocytogenes c) and S. flexneri d) inside Hep2 cell protrusions. Bars, 0.5 µm.

Updated on 13/05/2014



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Unité Interactions Bactéries-Cellules

Institut Pasteur
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