Reference - Detail
|Author||Nagai T, Abe A, Sasakawa C.|
|Title||Targeting of enteropathogenic Escherichia coli EspF to host mitochondria is essential for bacterial pathogenesis: critical role of the 16th leucine residue in EspF.|
|Journal||J Biol Chem|
The attachment of enteropathogenic Escherichia coli (EPEC) to host cells and the induction of attaching and effacing (A/E) lesions are prominent pathogenic features. EPEC infection also leads to host cell death and damage to the intestinal mucosa, which is partly dependent upon EspF, one of the effectors. In this study, we demonstrate that EspF is a mitochondrial import protein with a functional mitochondrial targeting signal (MTS), because EspF activity for importing into the mitochondria was abrogated by MTS deletion mutants. Substitution of the 16th leucine with glutamic acid (EspF(L16E)) completely abolished EspF activity. Infection of HeLa cells with wild type but not the espF mutant (DeltaespF) decreased mitochondrial membrane potential (DeltaPsi(m)), leading to cell death. The DeltaPsi(m) decrease and cell death were restored in cells infected with DeltaespF/pEspF but not DeltaespF/pEspF(L16E), suggesting that the 16th leucine in the MTS is a critical amino acid for EspF function. To demonstrate the impact of EspF in vivo, we exploited Citrobacter rodentium by infecting C3H/HeJ mice with DeltaespF(CR), DeltaespF(CR)/pEspF(CR), or DeltaespF(CR)/pEspF(L16E)(CR). These results indicate that EspF activity contributes to bacterial pathogenesis, as judged by murine lethality and intestinal histopathology, and promotion of bacterial colonization of the intestinal mucosa.
|MeSH||Amino Acid Sequence Animals COS Cells Carrier Proteins / chemistry Carrier Proteins / metabolism* Escherichia coli / metabolism* Escherichia coli / pathogenicity* Escherichia coli Proteins / chemistry Escherichia coli Proteins / metabolism* Green Fluorescent Proteins / metabolism HeLa Cells Humans Immunoblotting Intestinal Mucosa / microbiology Intestinal Mucosa / pathology Intracellular Membranes / microbiology Intracellular Signaling Peptides and Proteins L-Lactate Dehydrogenase / metabolism Leucine / chemistry* Membrane Potentials Mice Mice, Inbred C3H Microscopy, Fluorescence Mitochondria / metabolism* Mitochondria / microbiology* Molecular Sequence Data Plasmids / metabolism Protein Binding Protein Structure, Secondary Protein Structure, Tertiary Recombinant Fusion Proteins / metabolism Subcellular Fractions / metabolism Time Factors Valinomycin / pharmacology|
|WOS Category||BIOCHEMISTRY & MOLECULAR BIOLOGY|