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Published on: June 23, 2023
Cell Repolarization: A Bifurcation Study of Spatio-Temporal Perturbations of Polar Cells
Andreas Buttenschön1, Leah Edelstein-Keshet2
1Department of Mathematics, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada. abuttens@math.ubc.ca.
Abstract:
The intrinsic polarity of migrating cells is regulated by spatial distributions of protein activity. Those proteins (Rho-family GTPases, such as Rac and Rho) redistribute in response to stimuli, determining the cell front and back. Reaction-diffusion equations with mass conservation and positive feedback have been used to explain initial polarization of a cell. However, the sensitivity of a polar cell to a reversal stimulus has not yet been fully understood. We carry out a PDE bifurcation analysis of two polarity models to investigate routes to repolarization: (1) a single-GTPase ("wave-pinning") model and (2) a mutually antagonistic Rac-Rho model. We find distinct routes to reversal in (1) vs. (2). We show numerical simulations of full PDE solutions for the RD equations, demonstrating agreement with predictions of the bifurcation results. Finally, we show that simulations of the polarity models in deforming 1D model cells are consistent with biological experiments.
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