Characterization of VOPQ, A Type III Secreted Effector Protein from Vibrio Parahaemolyticus

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Title: Characterization of VOPQ, A Type III Secreted Effector Protein from Vibrio Parahaemolyticus
Author: Burdette, Dara Lesley
Abstract: Vibrio parahaemolyticus is a Gram -negative bacterium responsible for gastroenteritis associated with the consumption of raw or undercooked shellfish . Its most well -characterized virulence factors are hemolysins that cause b -hemolysis on a special blood agar . Mutants lacking these hemolysins are still virulent in animal and tissue culture models of infection . These phenomena can be attributed in part to one of two type III secretion systems ; one on chromosome 1 and the other on chromosome 2 . We demonstrate that Vibrio parahaemolyticus utilizes the type III secretion system on chromosome 1 to induce a temporally regulated series of events that initiates with the induction of autophagy , followed by cellular rounding and finally cellular lysis and death . To the best of our knowledge , no other Gram -negative extracellular bacterium has been shown to induce autophagy during infection . To understand the mechanism of Vibrio parahaemolyticus induced cell death , we focused our analysis on VopQ , a type III secreted effector encoded by the type III locus on chromosome 1 . We demonstrate that VopQ contributes to cytotoxicity as DvopQ strains induce cell lysis less efficiently . In addition , VopQ is necessary and sufficient for the induction of autophagy during infection . VopQ -mediated autophagy occurs independently of phosphatidylinositol 3 -kinases and prevents phagocytosis . Additional experiments using Saccharomyces cerevisiae demonstrate VopQ induces autophagy and cell death through an evolutionarily conserved mechanism . Results presented herein delineate a novel virulence mechanism used by Vibrio parahaemolyticus to cause disease . This study also highlights the effector VopQ as a novel inducer of autophagy and a key mediator of cytotoxicity during infection .
URI: http : / /hdl .handle .net /2152 .5 /264
Date: 2009-06-15

Citation

Characterization of VOPQ, A Type III Secreted Effector Protein from Vibrio Parahaemolyticus. Graduate School of Biomedical Sciences. Available electronically from http : / /hdl .handle .net /2152 .5 /264 .

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