ABSTRACT
Enterohaemorrhagic Escherichia coli (EHEC) belongs to a family of pathogens that cause attaching and effacing (A/E) lesion on target cells. The EspB protein of EHEC is translocated both to the host cell cytoplasm and to the membrane, and is essential for the signalling events leading to A/E lesion. To determine the actual role of EspB in this process, we tried to identify the EspB binding partner of the host cell protein, using a yeast two-hybrid assay, and obtained a cytoskeletal-associated protein, alpha-catenin. The alpha-catenin bound directly to the N-terminal region of EspB, both in solid (overlay assay) and solution (pull-down assay) phases, and it was recruited to the EHEC adherence site, dependent on EspB. Expression of the N-terminal region of EspB, as well as the whole EspB in host cells, inhibited F-actin accumulation on the adherence site. We conclude that EspB recruits alpha-catenin at the EHEC adherence site by direct interaction, and that the recruitment of alpha-catenin is essential for EHEC-induced A/E lesion formation.
Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Cytoskeletal Proteins/metabolism , Escherichia coli O157/metabolism , Escherichia coli Proteins/metabolism , Cells, Cultured , Cytoskeletal Proteins/chemistry , Cytoskeletal Proteins/genetics , Escherichia coli O157/pathogenicity , HeLa Cells , Humans , Recombinant Proteins/metabolism , alpha Catenin , beta-Galactosidase/analysisABSTRACT
Cortactin and the translocated intimin receptor, Tir, interacted with each other in pedestal formation in HeLa cells infected with enteropathogenic Escherichia coli (EPEC). Cortactin is shown to be necessary for organizing actin pedestals in response to EPEC, based on the expression of green fluorescent protein-fused cortactin derivatives in HeLa cells.
