Channel-mediated potassium uptake in Helicobacter pylori is essential for gastric colonization.
EMBO J
; 26(1): 232-41, 2007 Jan 10.
Article
en En
| MEDLINE
| ID: mdl-17159901
ABSTRACT
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 DeltahpKchA 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 11 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.
Texto completo:
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Bases de datos:
MEDLINE
Asunto principal:
Potasio
/
Canales de Potasio
/
Helicobacter pylori
/
Mucosa Gástrica
Límite:
Animals
Idioma:
En
Revista:
EMBO J
Año:
2007
Tipo del documento:
Article
País de afiliación:
Francia