Figure 1.

Individual cell and tissue mechanochemical models. (A) A diagram of mechanochemical interactions between active and inactive Rho GTPase levels and mechanical contraction and tension is shown and is adapted from Zmurchok et al. (19). (B) The mechanical model of an individual cell is shown. The model governs the position of the cell front $\left(x^f\right)$, back $\left(x^b\right)$, and center of mass $\left(x^{cm}\right)$ ((1d), (1e)). The cell is represented by a Hookean spring, with spring constant k, and dashpots at the cell front and back with constants ${\lambda }^f$ and ${\lambda }^b$, respectively. (C) (Top) Tension-dependent GTPase activation $f\left(T;\beta \right)$ (Eq. 1 b) and (bottom) tension-dependent front-back polarity ${ϵ}^f\left(T;\delta \right)$ (Eq. 1 f) are shown as functions of cellular tension T. (D) The mechanical model of n mechanically coupled cells is shown. The model governs the positions of cell fronts $\left(x_i^f\right)$ and backs $\left(x_i^b\right)$ for $i=1,\dots ,n$ ((2a), (2b), (2c), (2d), (2e)). Key differences between our model and that of Zmurchok et al. (19) include the fact that 1) cell front and back dashpot constants (${\lambda }^f$ and ${\lambda }^b$) are not equal, 2) ${\lambda }^f$ is cell tension dependent (via Eq. 1 f), and 3) cell-cell mechanical junctions are represented by Hookean springs, with spring constant ${\kappa }_{junc}$. To see this figure in color, go online.