Victor Sourjik's lab has moved to the Max-Planck-Institute of Terrestrial Microbiology in Marburg. Please note the new contact details in the left column!

Quantitative analyses of microbial networks

The majority of signalling and regulatory functions in the cell are executed by protein networks, and the aim of our research is to understand how these networks function in real time. We combine a range of genetic, biochemical and fluorescence-microscopy techniques, such as FRET and FRAP, with computational modelling to investigate temporal and spatial dynamics of signal processing by several networks in bacteria Escherichia coli and Bacillus subtilis and in the budding yeast. In bacteria, these are signalling networks that control chemotaxis and two-component environmental sensing, the chaperone network that regulates protein folding, the network of sugar transporters and the Min system that regulates cell division. In yeast, these are the MAP kinase signalling networks that mediate responses to pheromones and cell wall stress. We are particularly interested in understanding features that enable cellular networks to combine high sensitivity towards specific stimuli with robustness against non-specific perturbations. An important part of this is the analysis of regulated heterogeneity in microbial populations, which allows different subpopulations to optimally respond to unpredictable changes in the environment, the concept known as bet hedging. We further investigate plasticity of the microbial networks in adaptation to changing environment, including experimental microevolution of new phenotypes. Finally, we are exploiting our understanding of microbial networks to rationally re-design their functions, with potential biotechnological and medical applications.

Selected Publications



Di Ventura, B., Knecht, B., Andreas, H., Godinez, W.J., Fritsche, M., Rohr, K., Nickel, W., Heermann, D.W. and Sourjik, V. (2013) Chromosome segregation by the Escherichia coli Min system. Mol. Syst. Biol., 9: 686.
Kumar, M. and Sourjik, V. (2012) Physical map and dynamis of the chaperone network in Escherichia coli. Mol. Microbiol, 84: 736-47.
Oleksiuk, O., Jakovljevic, V., Vladimirov, N., Carvalho, R., Paster, E., Ryu, WS., Meir, Y., Wingreen, NS., Kollmann, M. and Sourjik, V. (2011) Thermal robustness of signaling in bacterial chemotaxis. Cell 145: 312-321.
Di Ventura, B. and Sourjik, V. (2011) Self-organized partitioning of dynamically localized proteins in bacterial cell division. Mol. Syst. Biol. 7: 457.
Neumann S, Hansen CH, Wingreen NS, Sourjik V. (2010) Differences in signalling by directly and indirectly binding ligands in bacterial chemotaxis. EMBO J. 29(20): 3484-95.
Boehm A, Kaiser M, Li H, Spangler C, Kasper CA, Ackermann M, Kaever V, Sourjik V, Roth V, Jenal U. (2010) Second messenger-mediated adjustment of bacterial swimming velocity. Cell 141(1):107-16.
Løvdok, L., Bentele, K., Vladimirov, N., Müller, A., Pop, F.S., Lebiedz, D., Kollmann, M., Sourjik, V. (2009) Role of translational coupling in robustness of bacterial chemotaxis pathway.. PLoS Biol.7:e1000171.
Kentner D, Sourjik V. (2009) Dynamic map of protein interactions in the Escherichia coli chemotaxis pathway. Mol. Syst. Biol. (2009) 5:238.
Schulmeister, S., Ruttorf, M., Thiem, S., Kentner, D., Lebiedz, D. and Sourjik, V. (2008) Protein exchange dynamics at chemoreceptor clusters in Escherichia coli. Proc. Natl. Acad. Sci. USA 105:6403-6408.
Thiem, S., Kentner, D. and Sourjik, V. (2007) Positioning of chemosensory clusters in E. coli and its relation to cell division. EMBO J., 26: 1615-1623.
Kollmann, M., Løvdok, L., Bartholome, K., Timmer, J. and Sourjik, V. (2005) Design principles of a bacterial signalling network. Nature, 438: 504-507.


Reviews

Sourjik, V. and Wingreen, N.S (2012) Responding to chemical gradients:bacterial chemotaxis. Curr. Opin. Cell Biol. 24: 262-8.
Sourjik, V. and Armitage, J.P. (2010) Spatial organization in bacterial chemotaxis. EMBO J. 29:2724-2733.
Kentner, D., Sourjik, V. (2010) Use of fluorescence microscopy to study intracellular signaling in bacteria. Annu. Rev. Microbiol.64:373-390. Epub 2010 Jun 7.
Sourjik, V. (2004) Receptor clustering and signal processing in E. coli chemotaxis. Trends Microbiol., 12: 569-576.