The N-terminal domain of EspF induces host cell apoptosis after infection with enterohaemorrhagic Escherichia coli O157:H7.
Enterohemorrhagic Escherichia coli (EHEC) employs a type III secretion system (TTSS) to export the translocator and effector proteins required for mucosal colonization. As an important bacterial effector protein in locus of enterocyte effacement four, the EspF protein causes F-actin filament aggregations to form attaching and effacing (A/E) lesions, and induces the destruction of brush-border microvilli and cytoskeletal rearrangements to form pedestals. However, the molecular pathogenesis of A/E lesions due to EHEC O157:H7 infection is unclear. In this study, we constructed an espF-deficient mutant (ΔespF) with a 162-bp deletion in the N-terminal domain by using overlap extension PCR. The results showed that EHEC EspF translocated into intestinal epithelial cells, targeted mitochondria and induced apoptosis. The ΔespF mutant, compared to EHEC prototype Guangzhou strain, had lower cell attachment and effacement abilities, lower caspase-9/3 and lactate dehydrogenase levels, lower bacterial adhesion, weaker mitochondria apoptosis, and a higher mouse survival rate. Our results demonstrate the probable function of the EspF N-terminal domain, which targets mitochondria and binds mitochondria heat shock protein 70 to induce cell apoptosis via A/E lesions. These findings may be invaluable in clarifying the molecular pathogenesis of EspF of EHEC O157:H7.
Department of Microbiology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, People's Republic of China.
Suhui
S
Zhao
Ying
Y
Zhou
Chunhui
C
Wang
Yu
Y
Yang
Xianbo
X
Wu
Yao
Y
Wei
Li
L
Zhu
Wei
W
Zhao
Qiwei
Q
Zhang
Chengsong
C
Wan
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001422:Bacterial Adhesion / Q000235:genetics; D058947:Bacterial Secretion Systems; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004927:Escherichia coli Infections / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D047908:Intracellular Signaling Peptides and Proteins; D053078:Membrane Potential, Mitochondrial; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation; D054730:Protein Interaction Domains and Motifs; D014774:Virulence / Q000235:genetics
D058947:Bacterial Secretion Systems; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C489109:EspFU protein, E coli; D047908:Intracellular Signaling Peptides and Proteins