title: Characterization of the NleF effector protein from attaching and effacing bacterial pathogens.
abstract: Enterohemorrhagic Escherichia coli (EHEC) is a water- and food-borne pathogen that causes hemorrhagic colitis. EHEC uses a type III secretion system (T3SS) to translocate effector proteins that subvert host cell function. T3SS-substrates encoded outside of the locus of enterocyte effacement are important to E. coli pathogenesis. We discovered an EHEC secreted protein, NleF, encoded by z6020 in O-island 71 of E. coli EDL933 that we hypothesized to be a T3SS substrate. Experiments are presented that probe the function of NleF and its role in virulence. Immunoblotting of secreted and translocated proteins suggest that NleF is secreted by the T3SS and is translocated into host cells in vitro where it localizes to the host cytoplasm. Infection of HeLa cells with E. coli possessing or lacking nleF and transient expression of NleF-GFP via transfection did not reveal a significant role for NleF in several assays of bacterial adherence, host cytoskeletal remodeling, or host protein secretion. However, competitive coinfection of mice with Citrobacter rodentium strains possessing or lacking nleF suggested a contribution of NleF to bacterial colonization. Challenge of gnotobiotic piglets also revealed a role for NleF in colonization of the piglet colon and rectoanal junction.
authors.affiliation: Center for Infectious Disease Research and Vaccinology, South Dakota State University, Brookings, SD 57007, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Echtenkamp
authors.forename: Wanyin
authors.initials: W
authors.lastname: Deng
authors.forename: Mark E
authors.initials: ME
authors.lastname: Wickham
authors.forename: Alejandra
authors.initials: A
authors.lastname: Vazquez
authors.forename: Jose L
authors.initials: JL
authors.lastname: Puente
authors.forename: Ajitha
authors.initials: A
authors.lastname: Thanabalasuriar
authors.forename: Samantha
authors.initials: S
authors.lastname: Gruenheid
authors.forename: B Brett
authors.initials: BB
authors.lastname: Finlay
authors.forename: Philip R
authors.initials: PR
authors.lastname: Hardwidge
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D044082:Citrobacter rodentium / Q000235:genetics* / Q000472:pathogenicity*; D003593:Cytoplasm / Q000737:chemistry; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D004847:Epithelial Cells / Q000737:chemistry / Q000382:microbiology; D019453:Escherichia coli O157 / Q000235:genetics* / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D013552:Swine; D014774:Virulence; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors