Study: Legionnaire Bacteria Work Together

Oct 24, 10:19 AM

Current Headlines: U.S. scientists have discovered bacterial proteins involved in Legionnaire's disease coordinate their activities to ensure their own survival.

What makes this pathogen special is that it can control transport of the vacuole formed after macrophages ingest the bacterium, said the study's lead author, Craig Roy, an associate professor of microbial pathogenesis at the Yale University's School of Medicine. It hijacks the vacuole and directs it to be transported to a nutrient-rich organelle called the endoplasmic reticulum, where the bacteria replicate in high numbers.

Roy's team identified the Legionella proteins involved in the hijacking. They found one protein, DrrA, turns on a molecular switch, Rab1, allowing Legionella to fuse the endoplasmic reticulum and the vacuole, creating a compartment that ensures bacterial survival. Another bacterial protein, LepB, turns off Rab1 after the bacteria enter the reticulum.

You can think of Legionella as being a crafty burglar that enters a cell and uses the protein DrrA to turn on a light, Rab1, that will illuminate the location of the safe -- the endoplasmic reticulum, said Roy. Once Legionella has cracked the safe, LepB, turns off the light to avoid detection.

The study's findings are detailed in the journal Nature.