Enteropathogenic Escherichia coli (EPEC) is able to inject its own receptor, a transmembrane
protein called translocated intimin receptor, Tir, into the host epithelial cell. The bacterium then uses an outer
membrane protein, intimin, to bind to Tir and remains firmly attached to the host cell surface for the duration of the
infection. The bacterium is also able to trigger the rearrangement of several host cell
proteins, culminating with the formation of an actin-rich, pedestal-like structure beneath the EPEC adherence site. Although several
cytoskeletal proteins are rearranged following EPEC
infection, the exact role played by these
proteins during pedestal formation remains unknown. We report here that
talin, an
integrin-
binding protein, is recruited by EPEC and associates directly with Tir. By surface plasmon resonance (SPR), the predicted value for the dissociation constant (KD) for Tir-
talin binding was 1.86 x 10(-7) M. We also demonstrate that microinjection of anti-
talin antibodies into HeLa cells resulted in the complete inability to focus actin filaments beneath the attached bacterium. These findings demonstrate that
talin is essential for EPEC-induced pedestal formation in infected cells.