title: TccP2-mediated subversion of actin dynamics by EPEC 2 - a distinct evolutionary lineage of enteropathogenic Escherichia coli.
abstract: Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhoea in developing countries. While colonizing the gut mucosa, EPEC triggers extensive actin-polymerization activity at the site of intimate bacterial attachment, which is mediated by avid interaction between the outer-membrane adhesin intimin and the type III secretion system (T3SS) effector Tir. The prevailing dogma is that actin polymerization by EPEC is achieved following tyrosine phosphorylation of Tir, recruitment of Nck and activation of neuronal Wiskott-Aldrich syndrome protein (N-WASP). In closely related enterohaemorrhagic E. coli (EHEC) O157 : H7, actin polymerization is triggered following recruitment of the T3SS effector TccP/EspF(U) (instead of Nck) and local activation of N-WASP. In addition to tccP, typical EHEC O157 : H7 harbour a pseudogene (tccP2). However, it has recently been found that atypical, sorbitol-fermenting EHEC O157 carries functional tccP and tccP2 alleles. Interestingly, intact tccP2 has been identified in the incomplete genome sequence of the prototype EPEC strain B171 (serotype O111 : H-), but it is missing from another prototype EPEC strain E2348/69 (O127 : H7). E2348/69 and B171 belong to two distinct evolutionary lineages of EPEC, termed EPEC 1 and EPEC 2, respectively. Here, it is reported that while both EPEC 1 and EPEC 2 triggered actin polymerization via the Nck pathway, tccP2 was found in 26 of 27 (96.2 %) strains belonging to EPEC 2, and in none of the 34 strains belonging to EPEC 1. It was shown that TccP2 was: (i) translocated by the locus of enterocyte effacement-encoded T3SS; (ii) localized at the tip of the EPEC 2-induced actin-rich pedestals in infected HeLa cells and human intestinal in vitro organ cultures ex vivo; and (iii) essential for actin polymerization in infected Nck-/- cells. Therefore, unlike strains belonging to EPEC 1, strains belonging to EPEC 2 can trigger actin polymerization using both Nck and TccP2 actin-polymerization signalling cascades.
authors.affiliation: Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Whale
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Rodrigo T
authors.initials: RT
authors.lastname: Hernandes
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, 5200 Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Tadasuke
authors.initials: T
authors.lastname: Ooka
authors.affiliation: Nationales Referenzlabor für Escherichia coli, Bundesinstitut für Risikobewertung, Diedersdorfer Weg 1, D-12277 Berlin, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Beutin
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free and University College Medical School, London, UK.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schüller
authors.affiliation: Fundación Caubet-Cimera, Recinto Hospital Joan March, Carretera Soller Km 1207110 Bunyola, Mallorca, Spain.
authors.forename: Junkal
authors.initials: J
authors.lastname: Garmendia
authors.affiliation: Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, UK.
authors.forename: Lynette
authors.initials: L
authors.lastname: Crowther
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Mônica A M
authors.initials: MAM
authors.lastname: Vieira
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, 5200 Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Ogura
authors.affiliation: Nationales Referenzlabor für Escherichia coli, Bundesinstitut für Risikobewertung, Diedersdorfer Weg 1, D-12277 Berlin, Germany.
authors.forename: Gladys
authors.initials: G
authors.lastname: Krause
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free and University College Medical School, London, UK.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Phillips
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Tania A T
authors.initials: TAT
authors.lastname: Gomes
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, 5200 Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, UK.
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
mesh_terms: D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D007421:Intestine, Small / Q000382:microbiology; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000378:metabolism; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D021381:Protein Transport; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C078332:Nck protein; D015513:Oncogene Proteins; C505370:tccP protein, E coli