Comparison of the motility of dynein complexes containing IC-2C and IC-1B in neurons. (A) Displacement tracking of IC-2C dynein. The positions of representative individual dynein puncta were tracked along the neurite in each frame of the videos, and the linear displacements (in micrometers) of 10 individual dynein puncta were graphed against time (in seconds). Anterograde movement is recorded as positive and retrograde movement as negative displacement. (B) Displacement tracking of IC-1B dynein. The positions of representative individual dynein puncta were tracked along the axon in each frame of the videos, and the linear displacements of 10 individual dynein puncta are graphed against time of movement. Anterograde movement is recorded as positive and retrograde movement as negative displacement. The initial positions of many of the puncta were set at 0, whereas the initial displacements of the some puncta were offset on the y axis to distinguish them on the graph. (C) Comparison of the retrograde interval velocity distributions of dynein complexes with the IC-2C and IC-1B isoforms in neurons. Velocities (μm/s) of individual retrograde movements of GFP–IC-2C dynein puncta between two frames were plotted against the frequency of their occurrence. Orange, IC-2C dynein (n = 592); green, IC-1B dynein puncta (n = 692).