Bacteria in bondage

Cells unleash proteins to cage unwanted invaders

DENVER Cells can trap some invading bacteria and slate them for destruction, a new study shows.

TRAPPED When bacteria called Shigella (shown in blue-green) get inside cells, the cells fight back by encasing some of the bacteria in cages made of proteins called septins (shown in red). S. Mostowy, P. Cossart

Serge Mostowy and Pascale Cossart of the Pasteur Institute in Paris discovered that when a type of diarrhea-causing bacteria called Shigella get inside cells, the cells fight back by encasing 10 to 30 percent of the bacteria in cages made of proteins called septins.

The cells then digest the trapped bacteria in a cellular process called autophagy, Cossart said December 4 at the annual meeting of the American Society for Cell Biology. The entrapment strategy works only on bacteria that are actively grabbing a cellular protein called actin and adding it to the comet-like tails that the microbes use to propel themselves through the cell. And the septins and autophagy proteins have to work together: If either fails to latch on to a bacterium, the microbe can escape.

The findings could eventually help researchers develop new therapies against Shigella and some other disease-causing bacteria by boosting cage-building components.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

More Stories from Science News on Life

From the Nature Index

Paid Content