Fig. 3.

Active coarsening is promoted by increased motor and cross-link density. (A) Steady-state actin patterns observed in active networks containing varying concentrations of myosin motors and biotin-streptavidin cross-links. Scale bar, 10 μm. (B) The average size of actomyosin condensates increases with increasing motor density (1∶400 biotin∶actin). (Inset) Confocal images show that this size increase results from an increased degree of coalescence. Scale bars 5 μm. (C) (i) The average speed of foci movement depends nonmonotonically on cross-link density (actin∶myosin ratio 1∶50). Open squares represent individual data points; open diamonds represent the average speed for each cross-linker density. (ii) The cross-linker density-dependence of the size of actomyosin condensates mirrors that of the contraction speed. All error bars represent SD.