Listeria monocytogenes impairs SUMOylation for efficient infection

Listeria takes on SUMO During infection the food-borne pathogen Listeria monocytogenes exploits a large number of the host cell's functions including post-translational modifications involving ubiquitinylation and phosphorylation, which specifically modify the activity of key proteins. The effects of pathogenic bacteria on the ubiquitin-like modification known as SUMOylation, an essential process in eukaryotic cells, remain largely unknown. Now a study in L. monocytogenes-infected human cells and in a mouse model shows that its virulence factor, listeriolysin O (LLO), induces a decrease in the levels of cellular SUMOylated proteins by triggering degradation of Ubc9, an essential enzyme of the SUMOylation machinery. This work suggests that Listeria — and probably other pathogens too — dampens the host response to infection by decreasing the SUMOylation level of key regulatory proteins.