The Type III Effectors NleE and NleB from Enteropathogenic E. coli and OspZ from Shigella Block Nuclear Translocation of NF-κB p65

PLoS Pathogens

Roy M. Robins-Browne¹  Barbara S. Coulson²  Elizabeth L. Hartland³  Mark Lucas³  David A. Jans⁴  Kylie M. Wagstaff⁵  James B. Kaper⁵  Alan D. Phillips⁵  Michelle A. Dunstone⁵  Hayley J. Newton⁶  Michelle Kelly⁶  Gad Frankel⁶  James C. Whisstock⁶  Jaclyn S. Pearson⁶  Luminita Badea⁶  Gavan Holloway⁶  Joan Sloan⁷ 

[1] ARC Centre for Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia;Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom;Centre for Pediatric Gastroenterology, UCL Medical School, Royal Free Campus, London, United Kingdom;Centre for Vaccine Development and Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America;Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia;Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia;Department of Microbiology, Monash University, Clayton, Victoria, Australia

关键词: Transcription factors;    HeLa cells;    Luciferase;    Shigella flexneri;    Bacterial pathogens;    Shigella;    Inflammation;    Shigellosis;   

DOI  :  10.1371/journal.ppat.1000898

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Many bacterial pathogens utilize a type III secretion system to deliver multiple effector proteins into host cells. Here we found that the type III effectors, NleE from enteropathogenic E. coli (EPEC) and OspZ from Shigella, blocked translocation of the p65 subunit of the transcription factor, NF-κB, to the host cell nucleus. NF-κB inhibition by NleE was associated with decreased IL-8 expression in EPEC-infected intestinal epithelial cells. Ectopically expressed NleE also blocked nuclear translocation of p65 and c-Rel, but not p50 or STAT1/2. NleE homologues from other attaching and effacing pathogens as well OspZ from Shigella flexneri 6 and Shigella boydii, also inhibited NF-κB activation and p65 nuclear import; however, a truncated form of OspZ from S. flexneri 2a that carries a 36 amino acid deletion at the C-terminus had no inhibitory activity. We determined that the C-termini of NleE and full length OspZ were functionally interchangeable and identified a six amino acid motif, IDSY(M/I)K, that was important for both NleE- and OspZ-mediated inhibition of NF-κB activity. We also established that NleB, encoded directly upstream from NleE, suppressed NF-κB activation. Whereas NleE inhibited both TNFα and IL-1β stimulated p65 nuclear translocation and IκB degradation, NleB inhibited the TNFα pathway only. Neither NleE nor NleB inhibited AP-1 activation, suggesting that the modulatory activity of the effectors was specific for NF-κB signaling. Overall our data show that EPEC and Shigella have evolved similar T3SS-dependent means to manipulate host inflammatory pathways by interfering with the activation of selected host transcriptional regulators.

【 授权许可】

CC BY