Project Summary New targets to combat Pseudomonas aeruginosa is paramount given the difficulty of treating Pseudomonas infections and increasing drug resistance of this pathogen. A major goal has been to target the type III secretion system that directly delivers toxins into host cells. However, this has yet to result in a clinical therapeutic. We recently discovered an unannotated regulator, PA1627, that controls expression of the type III secretion system. In this proposal, we will determine the regulation of PA1627 and determine how PA1627 controls the type III secretion system. Understanding this new level of control of the type III secretion can lead to new possibilities for combatting P. aeruginosa.