The bacterium often responsible for food poisoning, Salmonella enterica Typhimurium, exploits an enzyme produced by the host's intestinal cells to help it to invade them.
Beth McCormick at the University of Massachusetts Medical School in Worcester and her colleagues show that a protein produced by the bacterium to aid infection, SipA, activates a host enzyme called caspase-3 within hours of infection. Caspase-3 then cleaves SipA at a specific location, which triggers SipA to induce changes in the cells lining the gut that allow Salmonella to enter.
These reactions seem to occur on the outer surface of the intestinal cells. Knocking out the caspase-3 gene in mice resulted in a less virulent Salmonella infection.
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Microbiology: Salmonella gets help from host. Nature 467, 887 (2010). https://doi.org/10.1038/467887e
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DOI: https://doi.org/10.1038/467887e