Abstract

_Cells and tissues display remarkable robustness, i.e. the ability to keep a polarized or vectorial organization, important for their physiological role. Meanwhile epithelia show tremendous plasticity, during embryonic development and organ regeneration, i.e. the capacity to adapt to intrinsic or extrinsic signals or perturbations. We are interested in deciphering basic principles of cell and tissue organization and dynamics with a special focus on the problem of how robustness and plasticity are jointly regulated.

We want to understand how molecular machineries control cell polarity and cell shape changes and how these in turn affect tissue cohesion and plasticity. We study basic cell biological mechanisms, how developmental signals control these processes in space and time and how physical properties constrain their dynamics in vivo. The integration of physical and biochemical description of the processes we study is the major challenge we seek to address.

To this end we have developed multidisciplinary approaches spanning quantitative imaging, functional perturbations, methods to probe physical properties of tissues and numerical simulations to test our assumptions/hypothesis.

The main problem I will discuss is an example of tissue plasticity manifested in embryonic tissues. I will present our current research characterizing how the spatial distribution of tension in cells controls locally stereotyped cell shape changes and how these in turn are coordinated at the tissue level to produce tissue morphogenesis.

The presentation will delineate 1) spatio-temporal patterns in cell dynamics driving tissue morphogenesis; 2) the subcellular force generating systems driving these kinematic patterns; 3) how tension transmission affects this process.

We will discuss how fluctuations in contractile activity are spatially organized to yield robust and reproducible symmetry breaking in cell dynamics.

The underlying theme will be to understand how tissue level dynamics emerges from subcellular mechanics._