Flotillin-1 Regulates Enteropathogenic Escherichia coli Pedestal Length

Background The attaching and effacing (A/E) pathogens, enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC), remodel the host actin cytoskeleton to form actin-rich pedestals that anchor the bacteria atop intestinal epithelial cells. Although pedestal formation requires clathrin-endocytic proteins, the role of clathrin-independent proteins, like Flotillin-1 remain unclear. Methods Flotillin-1 localization in pedestal formation was analyzed using immunofluorescence microscopy during EPEC and EHEC infections in HeLa cells. This protein’s function was then examined using competing peptide interference and siRNA-mediated knockdown approaches. Results Flotillin-1 localizes to the Membranes of EPEC pedestals. Disruption of Flotillin-1 membrane association or depletion of Flotillin-1 using siRNA resulted in significantly elongated EPEC pedestals. A similar pattern of Flotillin-1 localization is seen at EHEC pedestals. Conclusion Our work expands current models of A/E host-pathogen interactions by highlighting a role for Flotillin-1 in controlling pedestal length.