Type III protein secretion systems (TTSSs) of Gram-negative plant and animal pathogens inject bacterial proteins, called effectors, into eukaryotic cells resulting in the modulation of host signal transduction pathways. Effector proteins are targeted to the TTSS by secretion signals carried in their N-termini and/or with the aid of specialized accessory proteins called type III chaperones (TTCs). Increasing our understanding of these processes may ultimately help in the design of pharmaceuticals and/or agricultural pesticides or herbicides. Thus, the intellectual merit of the proposed activity is quite significant because increasing our understanding of this topic may lead to better control of plant and animal diseases caused by pathogens dependent on TTSS. Project experiments were designed to explore the secretion signals used by effectors and the involvement of TTCs in the TTSS of the bacterial plant pathogen Pseudomonas syringae. The goal of several experiments is to determine the biological function of type III secretion signals. These experiments will utilize several different substrates of TTSSs, and will be focused on the role that N-terminal secretion signals and/or TTCs (and their binding sites) play in the secretion and translocation (injection into host cells) of effectors. The experiments in this project offer comprehensive training for students. The PI has initiated collaborations with a Nebraska program that targets the involvement of underrepresented minority students as well as collaborations with professors at local liberal arts colleges to reach students that may not have ample opportunities for a research experience.
