Nexilin is a dynamic protein at Listeria monocytogenes comet tails and enteropathogenic E. coli pedestals

Abstract

The extracellular pathogen enteropathogenic Escherichia coli (EPEC) and the intracellular bacterium Listeria monocytogenes (Listeria) control the actin cytoskeletal machinery during their infections as part of their disease processes. Through the subversion of this cytoskeletal system, motile actin‐rich structures (EPEC pedestals and Listeria comet tails) are generated. Nexilin, an actin‐binding protein, is thought to facilitate actin‐based cell motility. Consequently, we tested the hypothesis that nexilin is recruited to EPEC pedestals as well as Listeria comet tails and is needed for proper functioning of those structures. Using a combination of immunolocalization, RNA interference and time‐lapse imaging, we demonstrate that nexilin co‐localizes with actin in EPEC pedestals and Listeria comet tails. As stationary EPEC and Listeria becomes motile, nexilin focuses distally in these long actin‐rich structures. When nexilin expression was perturbed, EPEC pedestals remain unaltered, however Listeria comet tails had aberrant morphologies. Our data suggests that nexilin is redistributed to the dissociating end of actin filaments where it may act as a platform for bacterial propulsion when infecting host cells.Grant Funding Source: CIHR, NSERC, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, European Research Council, Howard Hughes Medical Institute