PLoS Pathog. 11(3):e1004694 2015/03/04

Many bacterial pathogens manipulate the actin cytoskeleton of mammalian cells to establish pathogenesis via invasion, the evasion of killing by phagocytes, the disturbance of a barrier function, and the induction of inflammation due to translocation of type III secretion (T3S) effector proteins. We demonstrated that a T3S effector protein (VopO) of the enteric pathogen Vibrio parahaemolyticus induces robust actin stress fiber formation in infected host cells. This aberrant actin rearrangement disrupts the barrier function in a colon epithelial cell line. Although many types of effector proteins have been reported, VopO shares no homology with previously reported effector proteins, and no putative functional motifs could be identified. Finally, we determined that direct binding of VopO to a RhoA guanine nucleotide exchange factor (GEF) is a key step in the induction of stress fibers. The findings presented in this study indicate that VopO plays a unique role in the pathogenicity of V. parahaemolyticus.