title: Cortactin recruitment by enterohemorrhagic Escherichia coli O157:H7 during infection in vitro and ex vivo.
abstract: Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important human pathogen that colonizes the gut mucosa via attaching and effacing (A/E) lesions; A/E lesion formation in vivo and ex vivo is dependent on the type III secretion system (T3SS) effector Tir. Infection of cultured cells by EHEC leads to induction of localized actin polymerization, which is dependent on Tir and a second T3SS effector protein, TccP, also known as EspF(U). Recently, cortactin was shown to bind both the N terminus of Tir and TccP via its SH3 domain and to play a role in EHEC-triggered actin polymerization in vitro. In this study, we investigated the recruitment of cortactin to the site of EHEC adhesion during infection of in vitro-cultured cells and mucosal surfaces ex vivo (using human terminal ileal in vitro organ cultures [IVOC]). We have shown that cortactin is recruited to the site of EHEC adhesion in vitro downstream of TccP and N-WASP. Deletion of the entire N terminus of Tir or replacing the N-terminal polyproline region with alanines did not abrogate actin polymerization or cortactin recruitment. In contrast, recruitment of cortactin to the site of EHEC adhesion in IVOC is TccP independent. These results imply that cortactin is recruited to the site of EHEC adhesion in vitro and ex vivo by different mechanisms and suggest that cortactin might have a role during EHEC infection of mucosal surfaces.
authors.affiliation: Division of Molecular and Cellular Biology, Imperial College London, London, United Kingdom.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Mousnier
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Whale
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schüller
authors.forename: John M
authors.initials: JM
authors.lastname: Leong
authors.forename: Alan D
authors.initials: AD
authors.lastname: Phillips
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
mesh_terms: D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000818:Animals; D001422:Bacterial Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D002648:Child; D051356:Cortactin / Q000378:metabolism*; D004847:Epithelial Cells / Q000382:microbiology; D019453:Escherichia coli O157 / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology; D051379:Mice; D009924:Organ Culture Techniques; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000378:metabolism
chemical_list: D000199:Actins; C495868:CTTN protein, human; D051356:Cortactin; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; C109287:Tir protein, E coli; C495771:WASL protein, human; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C505370:tccP protein, E coli