Fig. 1.

(a) Schematic illustration of a 2D cytoskeletal network (left). Filaments are represented by black arrows, motors by red bars, and cross-linkers by green dots. The network exerts a stress σ on the boundaries of the box, arising from tensions acting within the filaments (f_f) and within the motors (f_m). Motors move towards the arrowhead of filaments (for actin, the arrowhead corresponds to the barbed end). Network components stochastically exchange with a reservoir (right). (b) Motors move on filaments and rearrange the network on a time scale τ. Cross-linkers and actin filaments turn over on longer time scales τ_c > τ and τ_f > τ.