Figure 8.

Neural activity promotes spine growth in a manner that depends on the kinase activity of PKD1. A, Activity-driven increase in N-cadherin binding to PKD1 in cultured cortical neurons treated with KCl (12 mm) for 12 h; n = 4. **p < 0.01 (unpaired t test). B, Activity-driven increase in the amount of membrane-associated N-cadherin in cortical neurons treated with KCl (12 mm) for 12 h; n = 3. *p < 0.05 (unpaired t test). C₁, Representative images of DIV 15 hippocampal neurons transfected with GFP plus Vector, hPKD1, or DN-hPKD1 at DIV 8 and treated without or with KCl (12 mm) at DIV 10. Scale bars: Top, 50 μm; Bottom, 5 μm. C₂, Quantification of protrusion density, spine density, and filopodia density in neurons from the experiment shown in C₁ (n = 15, 15, 15, 14, 13, and 18 cells, respectively). ***p < 0.001 (two-way ANOVA with Bonferroni's post hoc test). C₃, Quantification of protrusion area, protrusion width, and protrusion length in neurons from the experiment shown in C₁ (n = 15, 15, 15, 14, 13, and 18 cells, respectively). ***p < 0.001 (two-way ANOVA with Bonferroni's post hoc test). Data are mean ± SEM.