Mar 20, 2014

EspC promotes epithelial cell detachment by enteropathogenic Escherichia coli via sequential cleavages of a cytoskeletal protein and then focal adhesion proteins

Infection and Immunity
Fernando Navarro-GarciaGabriela Tapia-Pastrana

Abstract

EspC is a non-locus of enterocyte effacement (LEE)-encoded autotransporter produced by enteropathogenic Escherichia coli (EPEC) that is secreted to the extracellular milieu by a type V secretion system and then translocated into epithelial cells by the type III secretion system. Here, we show that this efficient EspC delivery into the cell leads to a cytopathic effect characterized by cell rounding and cell detachment. Thus, EspC is the main protein involved in epithelial cell cytotoxicity detected during EPEC adhesion and pedestal formation assays. The cell detachment phenotype is triggered by cytoskeletal and focal adhesion disruption. EspC-producing EPEC is able to cleave fodrin, paxillin, and focal adhesion kinase (FAK), but these effects are not observed when cells are infected with an espC isogenic mutant. Recovery of these phenotypes by complementing the mutant with the espC gene but not with the espC gene mutated in the serine protease motif highlights the role of the protease activity of EspC in the cell detachment phenotype. In vitro assays using purified proteins showed that EspC, but not EspC with an S256I substitution [EspCS256I], directly cleaves these cytoskeletal and focal adhesion proteins. Kinetics of protein ...Continue Reading

Mentioned in this Paper

Protein Degradation, Regulatory
Extracellular
Squamous Transitional Epithelial Cell Count
Spnb2 protein, mouse
Protein Degradation, Metabolic
Focal Adhesions
Escherichia Coli Infections
Paxillin
Serine Endopeptidases
Process of Secretion

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