FIG. 4.
Inhibitors of phosphorylation at T668 significantly decrease the induction of GSK-3β induced by the AICD in differentiated PC12 cells. (a) At 48 h posttransfection, the protein levels of pC50T668, GSK-3β, and p-tau were examined by Western blotting after treatment with three kinase inhibitors, olomoucine (40 μM), roscovitine (5 μM), and LiCl (10 mM) in dPC12 cells. (b) GSK-3β promoter activity after treatment with olomoucine, roscovitine, or LiCl was measured by luciferase activity assay in dPC12 cells. (c) At 48 h posttransfection, the protein levels of C50 and pC50T668 were examined in the nuclear fraction (NF) and the cytoplasmic fraction (CF) by Western blotting after treatment with three kinase inhibitors, olomoucine (40 μM), roscovitine (5 μM), and LiCl (10 mM), in dPC12 cells. Data represent the means ± standard errors of the means of results from four separate experiments. *, P < 0.05; **, P < 0.01 (by ANOVA).