Channel-mediated potassium uptake in Helicobacter pylori is essential for gastric colonization

Autor(en): Stingl, Kerstin
Brandt, Sonja
Uhlemann, Eva-Maria
Schmid, Roland
Altendorf, Karlheinz 
Zeilinger, Carsten
Ecobichon, Chantal
Labigne, Agnes
Bakker, Evert P.
de Reuse, Hilde
Stichwörter: Biochemistry & Molecular Biology; Cell Biology; COMPLETE GENOME SEQUENCE; CYTOPLASMIC PH; ESCHERICHIA-COLI; gastric adaptation; IN-VIVO; INFECTION; K+ CHANNEL; mouse model; PORE; PROTEIN; RCK domain; RESISTANCE; SELECTIVITY; selectivity filter
Erscheinungsdatum: 2007
Volumen: 26
Ausgabe: 1
Startseite: 232
Seitenende: 241
To date, the biological role of prokaryotic K+ channels remains unknown. Helicobacter pylori contains a gene encoding a putative K+ channel (HpKchA) of the two-transmembrane RCK (regulation of K+ conductance) domain family, but lacks known bacterial K+ uptake systems. A H. pylori Delta hpKchA mutant presented a strong growth defect at low K+ concentration, which was compensated by KCl addition. The role of the separate RCK domain was investigated in H. pylori by mutagenesis of its internal start codon, which led to a K+-dependent intermediate growth phenotype, consistent with RCK activating channel function. Tagging HpKchA C-terminally, we detected a 1:1 stoichiometry of the full-length HpKchA and the separate RCK domain. We constructed single amino-acid exchanges within the unusual selectivity filter of HpKchA (ATGFGA) in H. pylori and observed complete loss (G74A), a slight defect (G76A or F75G) or wild-type (A77D) channel function. HpKchA was essential for colonization of the murine stomach. These data show, for the first time, a biological function for a prokaryotic K+ channel, as a K+ uptake system, essential for the persistence of H. pylori in the gastric environment.
ISSN: 02614189
DOI: 10.1038/sj.emboj.7601471

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