Tran Van Nhieu, G. , Ben-Ze'ev, A. & Sansonetti, P. J. Modulation of bacterial entry into epithelial cells by association between vinculin and the Shigella IpaA invasin. EMBO J. 16, 2717-2729

Unité de Pathogénie Microbienne Moléculaire, INSERM U389, Institut Pasteur, Paris, France.
The EMBO Journal (Impact Factor: 10.43). 06/1997; 16(10):2717-29. DOI: 10.1093/emboj/16.10.2717
Source: PubMed


Shigella flexneri is the causative agent of bacillary dysentery in humans. Shigella invasion of epithelial cells is characterized by cytoskeletal rearrangements and formation of cellular projections engulfing the bacterium in a macropinocytic process. We show here that vinculin, a protein involved in linking actin filaments to the plasma membrane, is a direct target of Shigella during cell invasion. IpaA, a Shigella protein secreted upon cell contact, rapidly associates with vinculin during bacterial invasion. Although defective for cell entry, an ipaA mutant is still able to induce foci of actin polymerization, but differs from wild-type Shigella in its ability to recruit vinculin and alpha-actinin. Presumably, IpaA-vinculin interaction initiates the formation of focal adhesion-like structures required for efficient invasion.

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    • "A role for vinculin during bacterial entry has been reported in the case of Shigella flexneri. Upon contact with epithelial cells, S. flexneri injects the IpaA protein into the host cell cytoplasm, where IpaA directly binds to vinculin inducing a dramatic rearrangement of the actin cytoskeleton to promote bacterial engulfment [24,25]. Vinculin has also been observed to be recruited to S. aureus–host cell contact sites or fibronectin-coated beads in epithelial, but not in endothelial cells [15,16,22]. "
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    ABSTRACT: Background Disease manifestations of Staphylococcus aureus are connected to the fibronectin (Fn)-binding capacity of these Gram-positive pathogens. Fn deposition on the surface of S. aureus allows engagement of α5β1 integrins and triggers uptake by host cells. For several integrin- and actin-associated cytoplasmic proteins, including FAK, Src, N-WASP, tensin and cortactin, a functional role during bacterial invasion has been demonstrated. As reorganization of the actin cytoskeleton is critical for bacterial entry, we investigated whether vinculin, an essential protein linking integrins with the actin cytoskeleton, may contribute to the integrin-mediated internalization of S. aureus. Results Complementation of vinculin in vinculin -/- cells, vinculin overexpression, as well as shRNA-mediated vinculin knock-down in different eukaryotic cell types demonstrate, that vinculin does not have a functional role during the integrin-mediated uptake of S. aureus. Conclusions Our results suggest that vinculin is insignificant for the integrin-mediated uptake of S. aureus despite the critical role of vinculin as a linker between integrins and F-actin.
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    • "Mice were euthanized, and their small intestines were removed, rinsed with complete DMEM medium (containing 2 mM L-glutamine and 10% fetal calf serum). The length of intestine was opened and submerged in buffer A (in mM: 120 NaCl, 4.7 KCl, 2.4 KCl, 1.2 KH2PO4, 1.2 Na2HP04, 25 NaHCO3, 10 HEPES, 5 EDTA, 0.5 DTT, 0.25% BSA; at pH 7.4 warmed to 37°C) for 20 min with agitation at 240 rpm [44]. Cells were collected by centrifugation (415.73 g – 2000 rpm – for 5 min) at room temperature, washed once with PBS and lysed by sonication (3 times, 10 s). "
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    • "These observations indicate that it may be possible to identify chimeric sequences for the Jα helix that maintain key interactions with the AsLOV2 domain but incorporate residues critical to peptide function. In this study, we use sequence comparisons along with molecular modeling to create AsLOV2 variants that embed the binding properties of the ipaA (Van Nhieu, et al., 1997) and SsrA (Levchenko, et al., 2003) peptides in the Jα helix. The usefulness of a photoswitch depends on how much the activity is enhanced by light irradiation (dynamic range) as well as the absolute activity in the dark and in the light. "
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