Dynein-mediated retrograde movement of early endosomes is significantly impaired in the Δp25 mutant, although dynein is still able to concentrate at microtubule plus ends. (A) mCherry-RabA–labeled early endosomes move and distribute along the wild-type hyphae, whereas they accumulate as a cloud at the hyphal tip in the Δp25 mutant and in the ΔnudA mutant. (B) A quantitative analysis of the frequency of movements toward or away from the hyphal tip. Because microtubules have mixed polarity in the multi-nucleate hyphae, we only focused on the small region within 10 µm behind the hyphal tip, where most of the plus ends of microtubules should face the hyphal tip. This experiment was done once with data combined from a total of 30 time-lapse sequences from the wild-type cells and a total of 30 time-lapse sequences from the Δp25 cells. For each time-lapse sequence, 30 frames were taken with a 0.1-s exposure time and a 0.3-s interval between frames. Frequency of movements in a total of 360 s is shown. (C) In both the wild type and the Δp25 mutant, GFP-labeled dynein heavy chains (HC) form comet-like structures representing their microtubule plus-end accumulation. Bars, 5 µm. (D) Mean and standard deviation values (error bars) of maximal signal intensity (arbitrary units) of the plus-end GFP-HC comets in Δp25 cells and wild-type cells are shown (n = 14, P < 0.01).