Apr. 17, 2009 A single crafty protein allows the deadly
bacterium Salmonella enterica to both invade cells lining the
intestine and hijack cellular functions to avoid destruction,
Yale researchers report in the April 17 issue of the journal
Cell. This evolutionary slight-of-hand sheds new insights into
the lethal tricks of Salmonella, which kills more than 2 million
people a year. "In evolutionary terms, this hijacking of
cellular machinery to diversify the function of a bacterial
protein is mind boggling,'' said Jorge Galan, senior author of
the paper and the Lucille P. Markey Professor of Microbial
Pathogenesis and Cell Biology and chair of microbial
pathogenesis at Yale. Salmonella causes disease when it takes
control of cells lining the intestinal track using its own
specialized "nano-syringe" called a type III secretion system.
Using this structure, Salmonella injects bacterial proteins that
mimic proteins of the host cell and help the pathogen avoid
destruction. The Yale study describes the crucial role