Reconstitution of cell Polarity and axis determination in a cell-free system

Cell polarity is a pre-requirement for many fundamental processes in animal cells, such as asymmetric cell division, axon specification, morphogenesis and epithelial tissue formation. Surprisingly, for all these different processes, polarization is established by the same set of proteins, called partitioning defective (PAR) proteins. Although the PAR proteins are highly conserved and found in all metazoans, it is still not clear how they establish cell polarity and how the spatiotemporal information they provide organizes the cell. This knowledge gap is mainly due to the limited accessibility of the living cell for controlled perturbations and live imaging, which makes a systematic characterization of the underlying molecular processes difficult to achieve. To overcome these limitations, we propose a dual approach combining in vitro and cell extract techniques. Thus, in one concerted effort, we will gain knowledge about the micrometer scale behavior of the polarizing system as well as the molecular properties of its components. With the help of biophysical modelling, we aim to connect these two different levels of information and obtain a deeper understanding of how this biochemical network establishes spatial information in the living cell.