Figure 6: Overexpressing importin-α reduces microtubule emanating frequency and compromises neuronal morphogenesis.

Cortical neurons were cotransfected with plasmids overexpressing importin-α (KPNA1, 4, 6) and EB3-mCherry before plating, incubated for 2 days before subjected to live cell imaging. (A) Kymographs of EB3-mCherry at the tip of neurites. (B–D) Quantification of EB3-mCherry dynamics in EGFP (control) and importin-α-overexpressing neurons. At least 10 neurons were analyzed per condition per repeat. (E) Representative images of dissociated hippocampal neurons transfected with plasmid overexpressing KPNA1, KPNA4, or KPNA6 at 2DIV and fixed at 4DIV. Images were inverted to enhance visualization. The scale bar presents 50 μm. Quantification of total neurite length (F), branch number per 200 μm neurite (G), and primary neurite number (H) of EGFP- and importin-α-overexpressing neurons. More than 50 neurons were analyzed for each group from 3 independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001, one-way ANOVA followed by Dunnett’s comparison to the control group. Error bars represent SEM from 3 independent experiments.