FIGURE 7.

Phosphorylation of CRMP1 by GSK3β diminishes its cellular activity. A, the C-terminal region of CRMP is sufficient to stabilize MTs upon GSK3 inhibition. Representative images of the distribution of CRMP1, CRMP1(1–490), CRMP1(480–572), CRMP2 and CRMP2(480–572) in COS7 cells following treatment with 20 mm LiCl for 2 h and then challenged with nocodazole (2 μm) for 45 min are shown. Red and yellow asterisks mark transfected cells scored as with or without stabilized MTs, respectively. The cells were fixed and stained with anti-HA and anti-tubulin antibodies. B, CRMP1(1–490), GST-CRMP1(480–572), CRMP2, and GST-CRMP2(480–572) were scored according to their ability to generate nocodazole-stable MTs. The yellow bars represent NaCl (control), and blue bars represent LiCl treatment before the nocodazole challenge. Cells with intact MTs that covered more than 50% of the area were scored as positive. (*, p < 0.05, **, p < 0.001, ***, p < 0.0001, one-way analysis of variance with Tukey's honestly significant difference post hoc test when compared with NaCl data).