Figure 7.

CDK5 mediated AIS shortening via reorganization of microtubules. A, Time course of the experiments. HCF slices were incubated with stabilizers of microtubules (MT) or actin during treatment with 2 × [K⁺] medium, FSK or PMA, or okadaic acid for 7–10 DIV. B, Pharmacological manipulation of microtubule dynamics. C, Effects of MT and actin filament stabilizers on AIS of NM neurons in 2 × [K⁺] medium. D, E, MT stabilizers occluded AIS shortening by 2 × [K⁺] medium (D, left), by FSK, PMA (D, right), or by okadaic acid (E). AIS lengths for 2 × [K⁺] (green), FSK or PMA alone (light gray), and normal (1 × [K⁺]) medium (light gray) were from Figures 2I, 5D, and 1F (10 DIV), respectively; **p < 0.01 compared with 2 × [K⁺] (D, left), 1 × [K⁺] (E) by one-way ANOVA and post hoc test, FSK or PMA alone (D, right) by Kruskal–Wallis test. F–I, Taxol occluded AIS shortening by overexpression of p35 (G) or p35 together with CDK5 (H). Time course of experiments (F) and AIS length (I). p35 and p35 together with CDK5 are from Figure 6M; **p < 0.01 by Student's t test. Numbers in parentheses indicate the number of cells.