The fate of VgrG effector proteins in the type VI secretion process: a key issue in bacteria-host relationship.

Protein secretion in bacterial pathogens has been studied for decades. This process is a major weapon allowing bacteria to successfully infect their host. Recently, a novel system, the type VI secretion system (T6SS), was identified. It was revealed that genes encoding this system are present in the genome of hundreds of bacterial pathogens. In P. aeruginosa, a major cause of hospital-acquired infection, it was specifically associated with chronic infection. Yet, little is known about the eff ector proteins transported by the T6SS. One study in Vibrio cholerae pointed out to the existence of a member of the VgrG family, which is translocated into host cells and impact host cell signaling. We identified 10 vgrG genes from the P. aeruginosa genome. We collected data showing secretion of some VgrGs. We now aim at conducting a thorough and systematic analysis to elucidate the relevance of each P. aeruginosa VgrG in the interaction with host cell, and their importance during infection. The specific goals are: - Which VgrGs are secreted/translocated into host cells? - Which impact each VgrG has on host cell response? - What is the relevance of each VgrG in a model of chronic infection? - What is the VgrG function?