Renthof 6, 35032 Marburg
+49-6421 28 24326
My research interests cover a broad range of topics in theoretical soft condensed matter, biological physics, and quantitative (systems) biology. On the one hand, I am studying the mechanical and dynamical properties of biological and soft condensed matter. Here, main themes of my research are morphological transitions, shape fluctuations and instabilities, and the emergence of order (for details see homepage). On the other hand, I am using physical methods to investigate the physiological properties of microbiological systems. Here, the long-term goal is to establish quantitative links between molecular scales and cell physiology.
In Caulobacter crescentus the position of the cell division plane is regulated by the MipZParB system. It is based on the ParB protein that binds to a specific chromosomal region (close to ori) and thus localizes to the poles during DNA replication and segregation. ParB interacts with the ParA-ATPase MipZ leading to a gradient in the distribution of this protein in the cell. Since MipZ inhibits FtsZ activity, this asymmetrical distribution of MipZ is directly responsible for the positioning of the cell division site. Thus, the MipZ-ParB system has a similar function as, e.g., the Min-system in E. coli. However, interestingly, this molecular machinery leads here to an asymmetric cell division into two daughter cells with different life styles. In close collaboration with the experimental group of Martin Thanbichler we theoretically investigate how the MipZ gradient is implemented molecularly. To do so we have developed a lattice-gas simulation to theoretically identify the critical interactions and parameters.
In S. cerevisiae the Fus3/Kss1-MAPK-pathways regulate two differentiation programs, the fusion of cells and the formation of biofilms. At the center of the pathway are four regulators, the MAPK Fus3 and Kss1 and the transcription factors Ste12 and Tec1. The MAPK activate Ste12 that then induces cell fusion. Ste12 also stimulates biofilm formation by Fus3. To improve our understanding of this complex signaling module we (in close collaboration with the experimental group of Hans-Ulrich Mösch) are experimentally and theoretically analyzing the spatial and temporal dynamics of the components of the Fus3/Kss1 pathways. In the theoretical model of the network we discuss the switch in the context of cellular physiology. We have also developed an assay that allows us to measure the concentrations of the relevant molecular players on the single cell level. With his approach we will be able to investigate how a sharp response of the switch is realized in the presence of transcriptional noise and cell-to-cell variations in the concentrations of the participating proteins.