Pathogenic bacteria secrete effector proteins that target host cell Rho GTPases to manipulate the actin cytoskeleton.A recent study in Nature identifies the Pyrin inflammasome as a sensor of this pathogenic process.
The ability to detect the presence of bacteria is crucial for life in multicellular organisms.While trillions of bacteria constitutively colonize many locations both on and inside the host,the vast majority of these pose no immediate threat.To avoid unnecessary use of resources and collateral tissue damage,the host has to carefully assess which bacteria defensive responses should be initiated.How the immune system distinguishes between pathogenic and non-pathogenic bacteria has been one of the most intriguing questions in immunology.