Figure 2.

Cell adhesion and polarization represented by a 1D spring model. Springs with constants k_c and k_m represent the elasticity of the cell and matrix respectively. Elastic morphological changes upon cell adhesion (a → b) are represented here by a change in the cellular spring length $-\mathrm{\Delta }{l}_c^0=l_c^0-l_c^R>0$. This triggers an internal feedback mechanism (b→c) that results in an enhancement of the active forces (see Eq. 2).