• MeSH
• biologie buňky * MeSH
• lidé MeSH
• mikrobiologie * MeSH
• sekreční systém typu VI metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• rozhovory MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• bakteriální proteiny MeSH
• faktory virulence MeSH
• Francisella tularensis * MeSH
• Francisella MeSH
• lidé MeSH
• makrofágy MeSH
• sekreční systém typu VI * MeSH
• tularemie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• komentáře MeSH
• práce podpořená grantem MeSH
• úvodníky MeSH

BACKGROUND: The genome of Pseudomonas aeruginosa contains at least three genes encoding eukaryotic-type Ser/Thr protein kinases, one of which, ppkA, has been implicated in P. aeruginosa virulence. Together with the adjacent pppA phosphatase gene, they belong to the type VI secretion system (H1-T6SS) locus, which is important for bacterial pathogenesis. To determine the biological function of this protein pair, we prepared a pppA-ppkA double mutant and characterised its phenotype and transcriptomic profiles. RESULTS: Phenotypic studies revealed that the mutant grew slower than the wild-type strain in minimal media and exhibited reduced secretion of pyoverdine. In addition, the mutant had altered sensitivity to oxidative and hyperosmotic stress conditions. Consequently, mutant cells had an impaired ability to survive in murine macrophages and an attenuated virulence in the plant model of infection. Whole-genome transcriptome analysis revealed that pppA-ppkA deletion affects the expression of oxidative stress-responsive genes, stationary phase σ-factor RpoS-regulated genes, and quorum-sensing regulons. The transcriptome of the pppA-ppkA mutant was also analysed under conditions of oxidative stress and showed an impaired response to the stress, manifested by a weaker induction of stress adaptation genes as well as the genes of the SOS regulon. In addition, expression of either RpoS-regulated genes or quorum-sensing-dependent genes was also affected. Complementation analysis confirmed that the transcription levels of the differentially expressed genes were specifically restored when the pppA and ppkA genes were expressed ectopically. CONCLUSIONS: Our results suggest that in addition to its crucial role in controlling the activity of P. aeruginosa H1-T6SS at the post-translational level, the PppA-PpkA pair also affects the transcription of stress-responsive genes. Based on these data, it is likely that the reduced virulence of the mutant strain results from an impaired ability to survive in the host due to the limited response to stress conditions.

• MeSH
• bakteriální proteiny genetika   MeSH
• bakteriální RNA genetika   MeSH
• buněčné linie MeSH
• delece genu MeSH
• fenotyp MeSH
• makrofágy mikrobiologie   MeSH
• mikrobiální viabilita MeSH
• myši MeSH
• oligopeptidy biosyntéza   MeSH
• oxidační stres MeSH
• protein-serin-threoninkinasy genetika   MeSH
• Pseudomonas aeruginosa genetika   růst a vývoj   patogenita   MeSH
• regulace genové exprese u bakterií MeSH
• salát (hlávkový) mikrobiologie   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• testy genetické komplementace MeSH
• transkriptom MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The success of pathogens depends on their ability to circumvent immune defences. Francisella tularensis is one of the most infectious bacteria known. The remarkable virulence of Francisella is believed to be due to its capacity to evade or subvert the immune system, but how remains obscure. Here, we show that Francisella triggers but concomitantly inhibits the Toll-like receptor, RIG-I-like receptor, and cytoplasmic DNA pathways. Francisella subverts these pathways at least in part by inhibiting K63-linked polyubiquitination and assembly of TRAF6 and TRAF3 complexes that control the transcriptional responses of pattern recognition receptors. We show that this mode of inhibition requires a functional type VI secretion system and/or the presence of live bacteria in the cytoplasm. The ability of Francisella to enter the cytosol while simultaneously inhibiting multiple pattern recognition receptor pathways may account for the notable capacity of this bacterium to invade and proliferate in the host without evoking a self-limiting innate immune response.

• MeSH
• adaptorové proteiny signální transdukční genetika   MeSH
• adaptorové proteiny vezikulární transportní genetika   MeSH
• faktor 3 asociovaný s receptory TNF metabolismus   MeSH
• faktor 6 asociovaný s receptory TNF metabolismus   MeSH
• Francisella tularensis imunologie   patogenita   MeSH
• imunitní únik imunologie   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• přirozená imunita imunologie   MeSH
• protein MyD88 genetika   MeSH
• receptory rozpoznávající vzory antagonisté a inhibitory   MeSH
• sekreční systém typu VI metabolismus   MeSH
• tularemie imunologie   mikrobiologie   patologie   MeSH
• ubikvitinace imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH