title: TccP is an enterohaemorrhagic Escherichia coli O157:H7 type III effector protein that couples Tir to the actin-cytoskeleton.
abstract: Subversion of host cell actin microfilaments is the hallmark of enterohaemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli infections. Both pathogens translocate the trans-membrane receptor protein-translocated intimin receptor (Tir), which links the extracellular bacterium to the cell cytoskeleton. While both converge on neural Wiskott-Aldrich syndrome protein (N-WASP), Tir-mediated actin accretion by EPEC and EHEC differ in that Tir(EPEC) requires both tyrosine phosphorylation and the host adaptor protein Nck, whereas Tir(EHEC) is not phosphorylated and utilizes an unidentified linker. Here we report the identification of Tir-cytoskeleton coupling protein (TccP), a novel EHEC effector that displays an Nck-like coupling activity following translocation into host cells. A tccP mutant did not affect Tir translocation and focusing but failed to recruit alpha-actinin, Arp3, N-WASP and actin to the site of bacterial adhesion. When expressed in EPEC, bacterial-derived TccP restored actin polymerization activity following infection of an Nck-deficient cell line. TccP has a similar biological activity on infected human intestinal explants ex vivo. Purified TccP activates N-WASP stimulating, in the presence of Arp2/3, actin polymerization in vitro. These results show that EHEC translocates both its own receptor (Tir) and an Nck-like protein (TccP) to facilitate actin polymerization.
authors.affiliation: Centre for Molecular Microbiology and Infection, Department of Biological Sciences, Imperial College London, UK.
authors.forename: Junkal
authors.initials: J
authors.lastname: Garmendia
authors.forename: Alan D
authors.initials: AD
authors.lastname: Phillips
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Carlier
authors.forename: Yuwen
authors.initials: Y
authors.lastname: Chong
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schüller
authors.forename: Olivier
authors.initials: O
authors.lastname: Marches
authors.forename: Sivan
authors.initials: S
authors.lastname: Dahan
authors.forename: Eric
authors.initials: E
authors.lastname: Oswald
authors.forename: Rob K
authors.initials: RK
authors.lastname: Shaw
authors.forename: Stuart
authors.initials: S
authors.lastname: Knutton
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
mesh_terms: D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D003599:Cytoskeleton / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007082:Ileum; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D009924:Organ Culture Techniques; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D029968:Escherichia coli Proteins; C078332:Nck protein; D015513:Oncogene Proteins; D011956:Receptors, Cell Surface; C109287:Tir protein, E coli