pH sensing by intracellular Salmonella induces effector translocation.
Science
; 328(5981): 1040-3, 2010 May 21.
Article
em En
| MEDLINE
| ID: mdl-20395475
ABSTRACT
Salmonella enterica is an important intracellular bacterial pathogen of humans and animals. It replicates within host-cell vacuoles by delivering virulence (effector) proteins through a vacuolar membrane pore made by the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (T3SS). T3SS assembly follows vacuole acidification, but when bacteria are grown at low pH, effector secretion is negligible. We found that effector secretion was activated at low pH from mutant strains lacking a complex of SPI-2-encoded proteins SsaM, SpiC, and SsaL. Exposure of wild-type bacteria to pH 7.2 after growth at pH 5.0 caused dissociation and degradation of SsaM/SpiC/SsaL complexes and effector secretion. In infected cells, loss of the pH 7.2 signal through acidification of host-cell cytosol prevented complex degradation and effector translocation. Thus, intravacuolar Salmonella senses host cytosolic pH, resulting in the degradation of regulatory complex proteins and effector translocation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Salmonella typhimurium
/
Proteínas de Bactérias
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Vacúolos
/
Fatores de Virulência
Limite:
Humans
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article