FIGURE 1:

Centrosome centering by pulling forces. (A) Simulation in which the motors are distributed in the cell. (B) Simulation in which the motors are distributed only on the edge the cell. Dynein motors are shown in green and MTs in black. Right, centrosome positions, indicated by colored points, from blue (0 s) to red (400 s). Left, centrosome trajectories. The gray area is the area filled by motors. (C) Variation of the number of motors for both cytoplasmic and cortical motor distribution. Fifteen trajectories are shown on each plot, in which the number of simulated dyneins is increased from 0 to 7000 with a step of 500. The initial position of the centrosomes was set on an arc axis to make them all visible on a single plot. This should not affect the outcome of the simulation, since the system has rotational symmetry. In all cases, the centrosomes are initially placed at a distance from the center corresponding to half the cell radius. Right, maximal speed reached by the centrosome during each simulation as a function of the number of dyneins for both cortical and cytoplasmic distributions. Each symbol is the result of one simulation, and the lines are guides for the eye.