title: The Surface Sensor NlpE of Enterohemorrhagic Escherichia coli Contributes to Regulation of the Type III Secretion System and Flagella by the Cpx Response to Adhesion.
abstract: Although the adhesion of enterohemorrhagic Escherichia coli (EHEC) is central to the EHEC-host interaction during infection, it remains unclear how such adhesion regulates virulence factors. Adhesion to abiotic surfaces by E. coli has been reported to be an outer membrane lipoprotein NlpE-dependent activation cue of the Cpx pathway. Therefore, we investigated the role of NlpE in EHEC on the adhesion-mediated expression of virulence genes. NlpE in EHEC contributed to upregulation of the locus of enterocyte effacement (LEE) genes encoded type III secretion system and to downregulated expression of the flagellin gene by activation of the Cpx pathway during adherence to hydrophobic glass beads and undifferentiated Caco-2 cells. Moreover, LysR homologue A (LrhA) in EHEC was involved in regulating the expression of the LEE genes and flagellin gene in response to adhesion. Gel mobility shift analysis revealed that response regulator CpxR bound to the lrhA promoter region and thereby regulated expressions of the LEE genes and flagellin gene via the transcriptional regulator LrhA in EHEC. Therefore, these results suggest that the sensing of adhesion signals via NlpE is important for regulation of the expression of the type III secretion system and flagella in EHEC during infection.
authors.affiliation: Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan tshimizu@faculty.chiba-u.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Ichimura
authors.affiliation: Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Noda
mesh_terms: D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells; D054324:Enterohemorrhagic Escherichia coli / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D006801:Humans; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D000069296:Type III Secretion Systems / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C095021:NlpE protein, E coli; D000069296:Type III Secretion Systems; D037521:Virulence Factors; C085504:CpxR protein, Bacteria