Figure 6.

JIP3 mediates anterograde TrkB transport. A, JIP3 influences the localization of TrkB-FL-GFP in PC12 cells. Distribution of TrkB-FL-GFP in the tips of differentiated PC12 cells, which were cotransfected with TrkB-FL-GFP and distinctive constructs (scramble siRNA, siJIP3, HAJIP3, or HAJIP3ΔCC1) and induced to differentiation for 2 d with 50 ng/ml NGF. The cells were fixed, and the relative TrkB-FL-GFP distribution in the tips of cells was measured. Arrows indicate the tips of PC12. The transfected siRNA is shown in red. The expression of JIP3 or JIP3ΔCC1 was detected by immunostaining with anti-HA antibodies (red); the localization of TrkB-FL-GFP is shown in green. B, Quantitative analysis of the localization of TrkB-FL-GFP in the tips of PC12 cells in A. The values expressed as mean ± SEM from three independent experiments (n = 3; *p < 0.05, vs the scramble siRNA group; one-way ANOVA). C, JIP3 influences the localization of endogenous TrkB at the distal axon. Cultured hippocampal neurons transfected with HAJIP3 or the dominant-negative form of JIP3 (HAJIP3ΔCC1), siJIP3, siRab27B, or siJIP3 + siRab27B at 3 DIV were stained for the endogenous TrkB at 5 DIV. The transfected siRNA is shown in red. The expression of HAJIP3 or HAJIP3ΔCC1 was detected by immunostaining with anti-HA antibodies (red), and the endogenous TrkB was detected by immunostaining with anti-TrkB antibodies (green). Scale bar, 10 μm. D, Quantitative analysis of the localization of endogenous TrkB at a distal axon or dendrites in C. The values shown are the mean ± SEM from three independent experiments (n = 3; *p < 0.05; **p < 0.01, vs scramble siRNA group; ^#p < 0.05, vs siJIP3 + siRab27B group; one-way ANOVA). E, Quantitative analysis for the localization of endogenous TrkB at a distal axon in the presence of MDC. Data shown are the mean ± SEM of three independent experiments (n = 3; *p < 0.05, vs the scramble siRNA + MDC group; one-way ANOVA).