The researchers tested the hypothesis that SNARE-like proteins expressed by the bacteria themselves were capable to interact with the eukaryotic SNAREs and alter membrane fusion to their advantage. The Chlamydia bacteria expressed a SNARE-like protein called IncA and the Legionella expressed a SNARE-like protein called IcmG/DotF, both of which inhibit SNARE-protein-mediated fusion.

"Based on our results, it seems that intracellular bacteria are able to express 'inhibitory SNAREs' to block fusion between the lysosome and the compartment containing the bacteria," Dr. Paumet said. "The SNARE proteins function like a zipper, and without each half, they can't fuse."

SNARE-like bacterial proteins would appear to be a viable therapeutic target, since disruption of their protective function should render intracellular bacteria more susceptible to clearance from the phagosome.

"Thorough understanding of the bacterial SNARE-like protein system will give us the necessary tools to design such therapeutics," Dr. Paumet said.

Source: Thomas Jefferson University