Interaction between Enterohemorrhagic Escherichia coli O157:H7 EspFu and IRSp53 Induces Dynamic Membrane Remodeling in Epithelial Cells

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 induces the fort-nation of filamentous, actin-rich, pedestal-shaped structures beneath bacterial cells that have attached to intestinal epithelial cells. Pedestal formation requires the translocation of EHEC O157:H7 type III effectors. One of these type III effectors, EspFu, consists of an N-terminal signal sequence, which is necessary for the translocation of EspFu into the host cell through a type III secretion system, and almost identical proline-rich repeats (PRRs), which control actin rearrangement and increase the efficiency of actin assembly in the host cell. In this study, we report that insulin receptor tyrosine kinase substrate p53 (IRSp53) in the host cell acts as a binding partner for EspFu. Co-immuno-precipitation and fluorescence microscopy showed specific interactions between EspFu and IRSp53 as well as their co-localization in epithelial cells. Additionally, we demonstrated that the association between EspFu and IRSp53 induces dynamic membrane remodeling in epithelial cells.