Shigella actin-based motility in the absence of vinculin

Reports on the role of vasodilator-stimulated phosphoprotein (VASP) and proline-rich sequences in actin-based motility of Listeria and potentially of Shigella flexneri have led to the suggestion that vinculin might be an essential docking protein on the surface O2 motile Shigella. Therefore, whether vinculin had a functional role in Shigella actin-based motility was tested by examining Shigella infection of the vinculin-deficient F9 cell line variant 5.51. Shigella are able to form actin tails and surface protrusions in 5.51 cells that are indistinguishable from those they produce in F9 cells, and Shigella rates of intracellular movement and protrusion formation are similar in the two cell lines. These data disprove the model of Shigella actin-based motility in which vinculin is an essential docking protein for either the formation of actin tails or the acceleration of motile bacteria.