Figure 4.

Average velocities of gliding microtubules in dependence of N_a/N. The average velocity shows a sharp transition from slow to fast motility between N_a/N = 0.6 to 0.8 for both experimental and simulated data. The broad error bars during the transition represent the presence of different velocities in this region. The parameter values for the simulation are the same as in Fig. 2B. Experimental and simulation results for microtubule velocities as a function of microtubule length, as well as simulation results for motor numbers as low as 2 and 3, are presented in Figs. S1 and S2, respectively. To see this figure in color, go online.