Comparison of Theory and Experiments: Oscillation Pattern and the Number of Motors in Unperturbed Cells

(A�CC) Numerical results and (D�CF) experimental measurements of the time evolution of the SPB position (A, D), SPB velocity (B, E), and the amount of dynein motors on the upper (red) and the lower (blue) microtubules (C, F). (E, F) Thin lines with markers show the original data, while the thick lines show the median in sliding windows of ten data points. (C, F) When the SPB moves upwards (�� > 0), the red curve shows the number of dyneins on the leading microtubule, while the blue curve the number on the trailing microtubule. When the SPB moves downwards (�� Figures 2 and 3). The numerical solutions (A�CC) can be understood in a simple limit where the SPB moves with the maximal dynein velocity, dxSPB/dt = ����0 (Text S1, I.C). In this limit, oscillations have an exact triangular waveform. Furthermore, the dynein linear densities on the microtubules obey dn/dt �� konc and dn/dt �� 0, giving a parabolic dependence of the total number of dyneins at the leading microtubule on time, and small dynein numbers on the trailing microtubule, respectively (C). Asterisk (C) marks an example of a change of direction of the SPB motion. The results in (D�CF) come from a single cell; the averaged results based on 11 cells are shown in Figure S10. SPB velocity as a function of the difference in the number of motors on each side of the SPB is shown in Figure S11.