Role of type III secretory system and related exotoxins in infections induced by an opportunistic pathogen Pseudomonas aeruginosa

The T3SS is a needle-like nanomachine that injects virulence proteins (exotoxins) directly into eukaryotic cells to initiate infection. Fore effector proteins of P. aeruginosa, ExoS, Exo T, Exo U, and ExoY, modulate a variety of cellular functions for the pathogen's benefit via their enzymatic activity. P. aeruginosa is invasive or cytotoxic to host cells, depending on the T3SS effectors encoded. We pay special attention to data related to biochemical activities and cellular targets of T3SS effectors, and known molecular mechanisms leading to cytotoxicity and blocking of phagocytosis, two most proven consequences of enzymatic activity of fore exoenzymes.