FIGURE 5.

Myo9 moves to the plus-end of actin filaments. Movement of dual-fluorescence-labeled actin filaments was supported by Myo9-head (A), Myo9-head-4IQ (B), and myosin II HMM (C). Individual frames from time-lapse movies are shown on the left. Elapsed time (seconds) is indicated in each panel. Scale bars, 2 μm. The green tip marks the plus-end of an actin filament. Myo9-head, Myo9-head-4IQ, and myosin II HMM move filaments with their green tips trailing, indicating that both Myo9 and myosin II are plus-end-directed motors (see also supplemental movies). Histograms on the right display the number of filaments moving with the plus-end trailing (positive velocities) and leading (negative velocities), respectively. The histograms were fitted with a Gaussian function (gray lines).