Special Session 41: 

A 3d bulk-surface model for cell polarization

Davide Cusseddu
University of Sussex
England
Co-Author(s):    Anotida Madzvamuse, Stephanie Portet
Abstract:
Several cellular activities, such as directed migration, are coordinated by an intricate network of biochemical reactions which lead to a polarised state of the cell, in which cellular symmetry is broken, causing the cell to have a well defined front and back. Balancing biological complexity with mathematical tractability is one of the aims of the works by Mori {\it et al} (2008), Holmes and Edelstein-Keshet (2016), in which they propose a famous minimal model for polarisation, known as {\it wave pinning} model. We will present an extension of these works in a bulk-surface setting for 3-dimensional domains. We will show how a local perturbation of the surface component can trigger a propagative activation over the membrane. The interplay with the bulk component generates a stable profile with only a portion of the membrane strongly active. Depending on the type of proteins, these might represent the front and the back of the cell, or {\it viceversa}. Furthermore, we will present the {\it Coupled Bulk Surface Finite Element Method}, used to solve the model, together with a predictor-corrector method for the temporal discretisation. Numerical results will be presented that validate the mathematical predictions. \ \vspace{1cm} \ {\bf \Large References} \vspace{0.3cm} Mori, Y., Jilkine, A., and Edelstein-Keshet, L. (2008) {\it Wave-pinning and cell polarity from a bistable reaction-diffusion system}. Biophysical journal, 94(9):3684-3697.\vspace{0.1cm} Holmes, W. R. and Edelstein-Keshet, L. (2016) {\it Analysis of a minimal Rho-GTPase circuit regulating cell shape} Physical biology, 13(4):046001.