B-304. Mutational Analysis of YopN of Yersinia pestis

S. S. Joseph, G. V. Plano;
Univ. of Miami Miller Sch. of Med., Miami, FL.

Plague is considered to be one of the most deadly infectious diseases in history and is caused by the gram-negative pathogen Yersinia pestis. The pathogenesis of Y. pestis is credited, in part, to the presence of a virulence plasmid termed pCD1. This plasmid encodes for a type III secretion system (T3SS) that functions to deliver anti-host effector proteins directly into eukaryotic host cells. The Yersinia effectors (Yops) act to subvert host defenses by altering cell signaling pathways, resulting in anti-inflammatory and anti-phagocytic responses. The secretion of Yops is tightly regulated and requires a YopN/SycN/YscB/TyeA complex to block delivery prior to host cell contact in vivo and in the presence of calcium in vitro. In this study, a series of YopN tetra-alanine substitution mutants was constructed to identify regions and residues of YopN that are required to regulate Yop secretion. Over thirty mutants were created; however, only 4 mutants had a significant affect on the ability of YopN to regulate Yop secretion. Based on the crystal structure of the YopN/SycN/YscB/TyeA complex, these mutants mapped to regions of YopN that appear to be required for interaction with the SycN/YscB chaperone or TyeA. These results suggest that the central region of YopN may not play a direct role in blocking Yop secretion but rather may simply provide a specific spatial separation between the two functional domains at the amino- and carboxyl-termini.

268/B. Microbial Interactions with Host Cells - III

Wednesday, 1:00 pm | Poster Hall