The frequencies of organelle and dynein movements are decreased in the absence of Lis1. (A) Bar graph of anterograde and retrograde endosome flux in wild-type and Lis1Δ hyphae. Rates were calculated from the number of endosomes that crossed a line drawn perpendicular to and 10 µm away from the hyphal tip during 3 min of observation. For wild-type hyphae, 127 vesicles moved in the anterograde direction, and 177 vesicles moved in the retrograde direction. For Lis1Δ hyphae, eight vesicles moved in the anterograde direction, and five vesicles moved in the retrograde direction. Error bars represent SD. (B) Bar graph of the rate at which dynein particles enter and leave microtubule plus ends in wild-type and Lis1Δ hyphae. The frequency of anterograde particle movements in Lis1Δ hyphae was not significantly different from that of the wild-type strain (41 ± 4 per minute [SEM] vs. 35 ± 4 per minute, respectively; P = 0.357). The frequency of retrograde dynein particle movements in the absence of Lis1 was significantly lower than that of the wild-type strain (20 ± 6 per minute vs. 48 ± 4 per minute, respectively; P = 0.005; n = 347 [wild type]; n = 142 [Lis1Δ]).