title: Proteomic analysis of enterotoxigenic Escherichia coli (ETEC) in neutral and alkaline conditions.
abstract: Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in children and travelers to endemic areas. Secretion of the heat labile AB5toxin (LT) is induced by alkaline conditions. In this study, we determined the surface proteome of ETEC exposed to alkaline conditions (pH 9) as compared to neutral conditions (pH 7) using a LPI Hexalane FlowCell combined with quantitative proteomics. Relative quantitation with isobaric labeling (TMT) was used to compare peptide abundance and their corresponding proteins in multiple samples at MS/MS level. For protein identification and quantification samples were analyzed using either a 1D-LCMS or a 2D-LCMS approach.
  
  
  
  Strong up-regulation of the ATP synthase operon encoding F1Fo ATP synthase and down-regulation of proton pumping proteins NuoF, NuoG, Ndh and WrbA were detected among proteins involved in regulating the proton and electron transport under alkaline conditions. Reduced expression of proteins involved in osmotic stress was found at alkaline conditions while the Sec-dependent transport over the inner membrane and outer membrane protein proteins such as OmpA and the β-Barrel Assembly Machinery (BAM) complex were up-regulated.
  
  
  
  ETEC exposed to alkaline environments express a specific proteome profile characterized by up-regulation of membrane proteins and secretion of LT toxin. Alkaline microenvironments have been reported close to the intestinal epithelium and the alkaline proteome may hence represent a better view of ETEC during infection.
authors.affiliation: Department of Infectious Disease, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, SE-41346, Gothenburg, Sweden. lucia.gonzales@gu.se.
authors.forename: Lucia
authors.initials: L
authors.lastname: Gonzales-Siles
authors.affiliation: Nanoxis Consulting AB, SE-40016, Gothenburg, Sweden.
authors.forename: Roger
authors.initials: R
authors.lastname: Karlsson
authors.affiliation: Proteomics Core Facility at the University of Gothenburg, SE-43050, Gothenburg, Sweden.
authors.forename: Diarmuid
authors.initials: D
authors.lastname: Kenny
authors.affiliation: Nanoxis Consulting AB, SE-40016, Gothenburg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Karlsson
authors.affiliation: Department of Microbiology Tumor and Cell Biology, Karolinska Institutet, Stockholm, SE-17177, Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Sjöling
mesh_terms: D000251:Adenosine Triphosphatases; D000596:Amino Acids / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001427:Bacterial Toxins / Q000032:analysis / Q000378:metabolism; D015536:Down-Regulation; D004579:Electron Transport; D054307:Enterotoxigenic Escherichia coli / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D004768:Enterotoxins / Q000032:analysis / Q000378:metabolism; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways; D009876:Operon; D014176:Protein Biosynthesis; D040901:Proteomics; D053719:Tandem Mass Spectrometry / Q000379:methods; D014158:Transcription, Genetic; D014357:Trypsin / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D000596:Amino Acids; D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C078167:OMPA outer membrane proteins; D014357:Trypsin; D000251:Adenosine Triphosphatases
keywords: ATPase; Alkaline; BAM; ETEC; OmpA; Proteomics; pH regulation