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Ena/VASP proteins contribute to Listeria monocytogenes pathogenesis by controlling temporal and spatial persistence of bacterial actin‐based motility

2003; Wiley; Volume: 49; Issue: 5 Linguagem: Inglês

10.1046/j.1365-2958.2003.03639.x

1365-2958

Victoria Auerbuch, Joseph Loureiro, Frank B. Gertler, Julie A. Theriot, Daniel A. Portnoy,

Viral Infectious Diseases and Gene Expression in Insects

Summary The Listeria monocytogenes surface protein ActA mediates actin‐based motility by interacting with a number of host cytoskeletal components, including Ena/VASP family proteins, which in turn interact with actin and the actin‐binding protein profilin. We employed a bidirectional genetic approach to study Ena/VASP′s contribution to L. monocytogenes movement and pathogenesis. We generated an ActA allelic series within the defined Ena/VASP‐binding sites and introduced the resulting mutant L. monocytogenes into cell lines expressing different Ena/VASP derivatives. Our findings indicate that Ena/VASP proteins contribute to the persistence of both speed and directionality of L. monocytogenes movement. In the absence of the Ena/VASP proline‐rich central domain, speed consistency decreased by sixfold. In addition, the Ena/VASP F‐actin‐binding region increased directionality of bacterial movement by fourfold. We further show that both regions of Ena/VASP enhanced L. monocytogenes cell‐to‐cell spread to a similar degree, although the Ena/VASP F‐actin‐binding region did so in an ActA‐independent manner. Surprisingly, our ActA allelic series enabled us to uncouple L. monocytogenes speed from directionality although both were controlled by Ena/VASP proteins. Lastly, we showed the pathogenic relevance of these findings by the observation that L. monocytogenes lacking ActA Ena/VASP‐binding sites were up to 400‐fold less virulent during an adaptive immune response.