Axonal levels and distribution of DCV cargo and disrupted transport of lysosomal organelles in syd mutants. (A) Left, representative pre-bleach confocal micrographs of the A7 nerve in third instar larvae expressing ILP2-GFP in motor neurons. Right, quantification of the axonal ILP2-GFP signal intensity. a.u., arbitrary units. Scale bar: 10 µm. Number of larvae analyzed: control 8, Rab2 10, syd^z4/Df 12, Dhc-KD 12, Khc-KD 8, Arl8/Df 9, and unc-104^P350/^O3.1 12. (B) Neuromuscular junction of muscle fibers 6 and 7 in control, Rab2, and syd^z4/Df larval fillets. Numbers in blue indicate the distal five boutons in a single branch of a motor neuron ending. Blue triangles indicate the most distal bouton in the same branch and other branches as well. Scale bar: 5 µm. (C and D) Left and middle, ILP2-GFP signal intensity in the distal five boutons of individual branches. Thick black lines represent the mean intensity for each bouton number. Dashed red lines were produced by linear regression. Right, regression line slopes. The mean ± SEM is indicated. Number of terminals (larvae) analyzed: control 13 (7), Rab2 6 (3) in C; control 16 (8), syd^z4/Df 14 (8) in D. (E) Representative kymographs showing transport of Spinster-positive organelles in A7 motor axons of control and syd^z4/Df third instar larvae. Scale bar: 10 µm. (F) Left, directional distributions of Spinster-positive organelle transport velocities, expressed as angles, cf. Fig. 3, B–D. Actual velocities converted from angles have been added to the x axis. For both control and syd^z4/Df, the average directional distribution from 10 larvae is shown. Right, the relative static peak amplitude and the logarithmic ratio of retrograde to anterograde peak amplitude for the directional distributions at the left. Bar graphs in F represent the mean + SEM. Steel with control test (A, right), Student’s t test (right of C, D, and F).