title: A H+-gated urea channel: the link between Helicobacter pylori urease and gastric colonization.
abstract: Acidic media trigger cytoplasmic urease activity of the unique human gastric pathogen Helicobacter pylori. Deletion of ureI prevents this activation of cytoplasmic urease that is essential for bacterial acid resistance. UreI is an inner membrane protein with six transmembrane segments as shown by in vitro transcription/translation and membrane separation. Expression of UreI in Xenopus oocytes results in acid-stimulated urea uptake, with a pH profile similar to activation of cytoplasmic urease. Mutation of periplasmic histidine 123 abolishes stimulation. UreI-mediated transport is urea specific, passive, nonsaturable, nonelectrogenic, and temperature independent. UreI functions as a H+-gated urea channel regulating cytoplasmic urease that is essential for gastric survival and colonization.
authors.affiliation: VA Greater Los Angeles Healthcare System and Department of Physiology, University of California, Los Angeles, CA 90073, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Weeks
authors.forename: S
authors.initials: S
authors.lastname: Eskandari
authors.forename: D R
authors.initials: DR
authors.lastname: Scott
authors.forename: G
authors.initials: G
authors.lastname: Sachs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000737:chemistry; D002463:Cell Membrane Permeability; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation; D005744:Gastric Acid; D006031:Glycosylation; D016480:Helicobacter pylori / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009865:Oocytes / Q000201:enzymology; D011994:Recombinant Proteins / Q000378:metabolism; D013270:Stomach / Q000382:microbiology*; D013696:Temperature; D014508:Urea / Q000378:metabolism*; D014510:Urease / Q000378:metabolism*; D014981:Xenopus
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; C114527:UreI protein, Helicobacter pylori; D006639:Histidine; D014508:Urea; D014510:Urease