Modeling of the cellular actin network. (A) A simulation of myosin II–powered merging of formin-actin nodes. With a simulation condition of myosin abundance and filamin absence, the formin-actin nodes aggregate rapidly. White, actin; green, formin clusters; red, myosin II. (B) A kymograph generated by the computer simulations of aster trajectories. Trajectories of the asters are color-coded so that cold/hot colors correspond to asters that are behind/in front of the visible plane. Frequent aster merging was consistently observed in the wild-type control, whereas this process is abolished when cells had either formin or myosin inhibited. In the case of filamin inhibition, the merging takes less time and the asters are more dynamic. See Materials and methods for detailed parameter settings in the simulation.