Intracellular pathogens: A virus joins the movement

Bacteria perform astounding feats inside host cells, demonstrating that they are able to exploit principles of cell biology that so far have eluded some of the brightest human minds. Included in their repertoire is the ability to recruit cytoskeletal elements, appropriating them to the task of bacterial locomotion. Several species of three unrelated bacterial genera — Listeria, Shigella and Rickettsia — travel through the host cell cytoplasm, fueled by actin polymerization. Recently, a virus has propelled itself onto the stage of actin-based motility studies. Vaccinia virus has now been shown to move inside host cells in association with an actin tail [1], thus imitating the behavior of its bacterial role models.