An international research team led by Keith Ireton of the University of Central Florida has identified a new way by which pathogenic bacteria spread from cell to cell within an infected mammalian host (Nat. Cell Biol., DOI: 10.1038/ncb1964). Once inside a host cell, cells of pathogens such as the food-borne bacterium Listeria monocytogenes use their tails to swim around. When a bacterial cell propels itself into the host cell's membrane, it somehow overcomes the membrane's normal tension and forms a protrusion that is engulfed by a neighboring host cell, thereby spreading the infection. Ireton and colleagues determined that internalin C, a protein secreted by listerias, binds to Tuba, a mammalian cell protein. This interference impairs Tuba's usual binding with the protein N-WASP and limits the ability of Tuba and N-WASP to maintain membrane tension, giving listerias a way out. The findings might open avenues for fighting diseases associated with L. monocytogenes or other bacteria that spread in a similar fashion, the researchers note.