Investigation of protein-protein interaction important for pathogenesis of tularemia infection

Francisella tularensis, sometimes called as a "stealth pathogen", causes zoonotic disease tularemia. Uniqueness of this intracellular bacterium is due to its ability to infect, survive and replicate within host phagocytic cells and evade the host immune response. Because of its extreme infectivity, ability to cause disease via inhalation route, and absence of a vaccine licensed for human use, F. tularensis is classified as a potent biothreat agent. The escape from phagosome plays a key role in the virulence of the bacterium. Type VI secretion system and F. tularensis pathogenicity island proteins are involved in this process; however, the exact molecular virulence mechanisms of F. tularensis are not fully characterized yet. The aim of this work was to characterize host-pathogen protein-protein interactions, which direct the infection process to F. tularensis benefits. The minimal experimental approach was selected for identification of protein-protein interaction between the host and the pathogen. The selected secreted proteins from FPI of F. tularensis subspecies novicida were fused with an epitope anchor FLAG tag and expressed in HEK 293T cell line. Interaction partners were identified by affinity purification followed by nanoLC-MS/MS analysis. The data indicate that the bacterial protein IglJ..