B1: Polarity of cortex mechanics and fluidity

Lead PI: Andreas Janshoff
Collaborating PIs: Timo Betz, Sarah Köster, Peter Sollich, Claudia Steinem, Anne Wald
Overarching research question: Does mechanical polarity exist in epithelial cells and if so, how does it arise and depend on functional cell-cell contacts?

A large amount of data is available on the molecular details of the formation and maintenance of polarity, but information on the mechanical properties of the basolateral and apical membranes is rather sparse. Assessment of the apical side of confluent epithelial cells using nanoindentation devices is straightforward, whereas the basal side remains obscure. The interplay of membrane mechanics and cortex tension, as well as the presence of rapidly accessible surface reservoirs such as membrane folds and caveolae, dominate the response to external deformation. It is of great interest to study the evolution of certain viscoelastic properties over time, particularly in the context of epithelial maturation and the establishment of epithelial barrier function. To this end, it is of utmost importance to develop, on the one hand, new preparation strategies that improve the accessibility of the two compartments and, on the other hand, to design new theoretical models that capture the physics of the contractile cortex.

Core field: experimental biophysics

PhD training objectives: biophysical characterization methods (confocal/STED imaging, AFM); cell biological methods (cell culture, immunostaining, CRISPR-CAS); data analysis (image processing, force-relaxation data).