Enterohaemorrhagic and enteropathogenic Escherichia coli use different mechanisms for actin pedestal formation that converge on N-WASP.
Enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC), two closely related diarrhoeagenic pathogens, induce actin rearrangements at the surface of infected host cells resulting in the formation of pseudopod-like structures termed pedestals beneath intimately attached bacteria. We have shown previously that N-WASP, a key integrator of signalling pathways that regulate actin polymerization via the Arp2/3 complex, is essential for pedestal formation induced by EPEC using N-WASP-defective cell lines. Here we show that actin pedestal formation initiated by EHEC also depends on N-WASP. Amino acid residues 226-274 of N-WASP are both necessary and sufficient to target N-WASP to sites of EHEC attachment. The recruitment mechanism thus differs from that used by EPEC, in which amino-terminal sequences of N-WASP mediate recruitment. For EPEC, recruitment of N-WASP downstream of Nck has been postulated to be mediated by WIP. However, we find a direct interaction of N-WASP with WIP to be dispensable for EPEC-induced pedestal formation and present data supporting an F-actin-dependent localization of WIP to actin pedestals induced by both EPEC and EHEC. In summary, our data show that EPEC and EHEC use different mechanisms to recruit N-WASP, which is essential for actin pedestal formation induced by both pathogens.
Lommel
Silvia
S
Department of Cell Biology, German Research Centre for Biotechnology (GBF), Mascheroder Weg 1, 38124 Braunschweig, Germany. slo@gbf.de
Benesch
Stefanie
S
Rohde
Manfred
M
Wehland
Jürgen
J
Rottner
Klemens
K
D000199:Actins / Q000378:metabolism*; D002460:Cell Line; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D014774:Virulence / Q000235:genetics / Q000502:physiology; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal
D000199:Actins; D029968:Escherichia coli Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal