The Second Type VI Secretion System of Pseudomonas aeruginosa Strain PAO1 Is Regulated by Quorum Sensing and Fur and Modulates Internalization in Epithelial Cells

摘要: The genome of Pseudomonas aeruginosa PAO1 contains three type VI secretion systems (T6SSs) called H1-, H2-, and H3-T6SS. H1-T6SS secretes identified toxins that target other bacteria, providing a fitness advantage for P. aeruginosa, likely contributes to bacterial pathogenesis in chronic infections. However, no specific substrates or defined roles have been described the two systems. Here, we demonstrate expression H2-T6SS genes strain is up-regulated during transition from exponential stationary phase growth regulated by Las Rhl quorum sensing In addition, identify putative Fur boxes promoter region find transcription negatively iron. We also show system enhances uptake into HeLa cells (75% decrease internalization with mutant) lung epithelial through phosphatidylinositol 3-kinase-dependent pathway induces Akt activation host cell (50% phosphorylation). Finally, plays role virulence worm model. Thus, contrast H1-T6SS, modulates interaction eukaryotic cells. Together, T6SS can carry out different functions may be important establishing infections human host.