GtrS and GltR form a two-component system: the central role of 2-ketogluconate in the expression of exotoxin A and glucose catabolic enzymes in Pseudomonas aeruginosa.
Nucleic Acids Res
; 42(12): 7654-63, 2014 Jul.
Article
em En
| MEDLINE
| ID: mdl-24920832
ABSTRACT
In the human pathogen Pseudomonas aeruginosa, the GltR regulator is required for glucose transport, whereas GtrS is a sensor kinase that plays a key role in mediating bacteria-host interaction and pathogen dissemination in the host. We show that GtrS and GltR form a two-component system that regulates the expression from the promoters Pedd/gap-1, PoprB and Pglk, which control the expression of genes involved in glucose metabolism and transport. In addition, the GtrS/GltR pair regulates the expression of toxA that encodes exotoxin A, the primary virulence factor. Microcalorimetry-based ligand screening of the recombinant GtrS ligand-binding domain revealed specific binding of 2-ketogluconate (2-KG) (KD=5 µM) and 6-phosphogluconate (KD=98 µM). These effectors accelerate GtrS autophosphorylation, with concomitant transphosphorylation of GltR leading to a three-fold increase in transcription. Surprisingly, in vivo a similar increase in expression from the above promoters was observed for the mutant deficient in GltR regardless of the presence of effectors. The GltR operator site was found to contain the consensus sequence 5'-tgGTTTTTc-3'. We propose that 2-KG is a key metabolite in the stringent transcriptional control of genes involved in virulence and glucose metabolism. We show that GltR is a transcriptional repressor that is released from DNA upon phosphorylation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
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Pseudomonas aeruginosa
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Proteínas de Bactérias
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Toxinas Bacterianas
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Proteínas de Transporte de Monossacarídeos
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Regulação Bacteriana da Expressão Gênica
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ADP Ribose Transferases
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Fatores de Virulência
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Exotoxinas
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Gluconatos
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article