Project Description
The host colonization process by P. aeruginosa relies on the following sequential steps: i) planktonic cells migration towards a desired niche by flagellar motility, ii) adhesion onto the host by means of flagella or pili, iii) loss of flagella as a result of signal transduction and secretion of exopolysaccharide matrix, iv) development of a mature biofilm onto the CF mucosa lung and v) final detachment and swimming to another environment provoked by environmental cues (PMID: 12458153). The decreasing O2 gradient generated as a result of the thick mucosa of a cystic fibrosis transmembrane conductance regulator (CFTR) mutated CF lung and the biofilm density poses an adverse scenario to bacteria that P. aeruginosa circumvents by its versatile metabolism, which encompasses nitrate/nitrite respiration, arginine and pyruvate fermentation as predominant energy generating routes. On the other hand, a successful colonization of the human host and penetration through the thick mucus extensively depends on the construction of a highly developed flagellar machinery, which endows this monoflagellated bacterium with both motility and adhesion capacities. In a previous work our group revealed that FliC, although quantitatively scarce, was distributed alongside the extracytosolic region and not exclusively located at the pole where the sole flagellum of P. aeruginosa is constructed (Borrero et al 2015). The periplasmic location of FliC was discovered to take place in a triad-manner with two other proteins, the periplasmic nitrite reductase involved in denitrification and the presumably cytosolic ATP-dependent molecular chaperone DnaK. Beyond identifying the interlaced function of the nitrite reductase in swimming motility and flagellar assembly (Borrero et al 2015) no further characterization of a potentially alternative role of the DnaK besides its well-understood chaperone-like function in the flagellar export, construction or functionality has been pursued. In a recent study we monitored the location of DnaK and FliC throughout the different fractions and organelles of P. aeruginosa by harnessing scanning and transmission electron microscopy (S/TEM) coupled with single and double immunogold labelling, confocal microscopy and immunofluorescence and mass spectrometry (LC-MS/MS). Moreover, we deepened into the interaction model of DnaK-FliC by employing SPOT-membrane arrays pinpointing the interacting domains of both proteins leading to ultimately infer a docking model. We irrefutably demonstrate by different techniques an unexpected DnaK location at the flagellar filament co-localizing with FliC monomers and it to be embedded in a vesicle-like membranous structure. The aim of the follow-up project is to explore the dynamics of the protein-protein interactions underlying the flagellar and vesicle formation of P. aeruginosa employing diverse interactomics methods. Holistic characterization of the bacterial living system will be conducted using a multi-omics approach.
Hassett, D. J., Cuppoletti, J., Trapnell, B., Lymar, S. V., Rowe, J. J., Yoon, S. S., Hilliard, G. M., Parvatiyar, K., Kamani, M. C., Wozniak, D. J., Hwang, S-H., McDermott, R. R. & Ochsner, U. A. (2002) Adv. Drug Deliv. Rev. 54(11), 1425-1443.
Borrero-de Acuña, J. M., Molinari, G., Rohde, M., Dammeyer, T., Wissing, J., Jänsch, L., Arias, S., Jahn, M., Schobert, M., Timmis, K. N. & Jahn, D. (2015) J. bacteriol. 197(19), 3066-3075.
Principal Investigator(s)
Prof. Dr. Dieter Jahn
+49531-391-55101
d.jahn(at)tu-braunschweig.de
PhD-Student(s)
Viktoria Otto
+49531-391-5804
vi.otto(at)tu-braunschweig.de
Ilka Pusch
+49531-391-5890
i.pusch(at)tu-braunschweig.de
Former Members
Dr. José Manuel Borrero-de-Acuña
