Fig. 2.

The αTub84B K40A mutation does not affect the polarized distribution of Golgi outposts, but does affect lysosome motility in dendrites. (A–B‴) Golgi outposts, marked by ManII::GFP (green), localize to dendrites in both control (A–A‴) and αTub84B^K40A neurons (B–B‴). ManII::GFP (green in A,B; black in A′,A‴,B′,B‴) and CD4::Tomato (magenta in A,B, black in A″,B″) are expressed in class IV da neurons under the control of the ppk enhancer. Bracket, axon; arrowheads, Golgi outposts in dendrites. Scale bars: 25 µm. (C) Representative kymographs of lysosome dynamics in the dendrites of control (top) and αTub84B^K40A (bottom) neurons. Scale bar x-axis: 10 µm; scale bar y-axis: 10 s. Lysosomes are marked by Lamp1::GFP. The cell body is to the right. (D,E) In dendrites (D), lysosomes traveling in the retrograde direction in αTub84B^K40A neurons display increased flux (top) and reduced velocity (bottom). Lysosome motility in axons (E) is unaffected by the αTub84B K40A mutation. Dendrites (D, flux): 30 wild-type control dendrite segments and 29 αTub84B^K40A dendrite segments were analyzed (mean±s.d.); P=0.008. Dendrites (D, velocity): 32 wild-type control dendrite segments and 29 αTub84B^K40A dendrite segments were analyzed (mean±s.d.); P=0.012. Axons (E, flux): 7 wild-type control axons and 5 αTub84B^K40A axons were analyzed (mean±s.d.). Axons (E, velocity): 7 wild-type control axons and 5 αTub84B^K40A axons were analyzed (mean±s.d.). *P=0.01–0.05; **P=0.001–0.01; n.s., not significant (two-tailed Student's t-test).