Rho family GTPases control entry of Shigella flexneri into epithelial cells but not intracellular motility.

Joëlle Mounier (1) , Valérie Laurent (2) , A Hall (3) , Philippe Fort (4) , Marie-France Carlier (2) , Philippe Sansonetti (1) , Coumaran Egile (1)

1 Pathogénie Microbienne Moléculaire
2 LEBS - Laboratoire d'enzymologie et biochimie structurales
3 UCL - University College of London [London]
4 CRBM - Centre de recherches de biochimie macromoléculaire

Shigella flexneri, an invasive bacterial pathogen, promotes formation of two cytoskeletal structures: the entry focus that mediates bacterial uptake into epithelial cells and the actin-comet tail that enables the bacteria to spread intracellularly. During the entry step, secretion of bacterial invasins causes a massive burst of subcortical actin polymerization leading the formation of localised membrane projections. Fusion of these membrane ruffles leads to bacterial internalization. Inside the cytoplasm, polar expression of the IcsA protein on the bacterial surface allows polymerization of actin filaments and their organization into an actin-comet tail leading to bacterial spread. The Rho family of small GTPases plays an essential role in the organization and regulation of cellular cytoskeletal structures (i.e. filopodia, lamellipodia, adherence plaques and intercellular junctions). We show here that induction of Shigella entry foci is controlled by the Cdc42, Rac and Rho GTPases, but not by RhoG. In contrast, actin-driven intracellular motility of Shigella does not require Rho GTPases. Therefore, Shigella appears to manipulate the epithelial cell cytoskeleton both by Rho GTPase-dependent and -independent processes.

Domaines: Biologie moléculaire; Embryologie et organogenèse; Cancer; Systématique, phylogénie et taxonomie; Organisation et fonctions cellulaires [q-bio.SC]

Joëlle Mounier, Valérie Laurent, A Hall, Philippe Fort, Marie-France Carlier, et al.. Rho family GTPases control entry of Shigella flexneri into epithelial cells but not intracellular motility.. Journal of Cell Science, 1999, 112 ( Pt 13), pp.2069-80. ⟨hal-02267489⟩