Regensburg 2022 – scientific programme

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BP: Fachverband Biologische Physik

BP 22: Migration and Multicellular Systems

BP 22.3: Talk

Thursday, September 8, 2022, 10:15–10:30, H15

Bistability between sessile and motile solutions in a nonlinear active gel model for cell migration — •Oliver M. Drozdowski, Falko Ziebert, and Ulrich S. Schwarz — Institute for Theoretical Physics and BioQuant, Heidelberg University, 69120 Heidelberg, Germany

Cell motility is one of the hallmarks of life and often is based on flow in the actin cytoskeleton that is driven by myosin II motors. The standard model to describe such flows is active gel theory, in which myosin II contractility enters as active stress. Recently, we have shown how to include optogenetic control in a minimal active gel model [1]. Here we ask how active gel descriptions of motility need to be modified to explain the experimental observation that a cell's state can be switched between sessile and motile. We show that such bistability emerges in active gel theory if the myosin II motors are modeled as a supercritical van der Waals fluid, including volume exclusion and short-range attraction. We present phase diagrams in cell adhesion and contractility that include sessile, bistable and motile regimes in experimentally relevant parameter ranges. Including optogenetic perturbations of contraction, as done before for a simpler model [1], we find that such external activation can be used to control cell locomotion, in agreement with recent experiments [2].

[1] O. M. Drozdowski, F. Ziebert, and U. S. Schwarz, Phys. Rev. E 104, 024406 (2021),

[2] A. Hadjitheodorou, et al., Nat. Commun. 12, 6619 (2021).