Talin, a host cell protein, interacts directly with the translocated intimin receptor, Tir, of enteropathogenic Escherichia coli, and is essential for pedestal formation.
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.
Cantarelli
V V
VV
Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1, Suita, Osaka 565-0871, Japan.
Takahashi
A
A
Yanagihara
I
I
Akeda
Y
Y
Imura
K
K
Kodama
T
T
Kono
G
G
Sato
Y
Y
Honda
T
T
D000199:Actins / Q000378:metabolism; D004926:Escherichia coli / Q000472:pathogenicity* / Q000502:physiology*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D016608:Talin / Q000378:metabolism*; D014774:Virulence
D000199:Actins; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; D016608:Talin; C109287:Tir protein, E coli