Neuronal activity-dependent isoform-specific expression and alternative splicing of Shank3 . (A) q-PCR analysis of Shank3 isoforms in cultured mouse cortical neurons after treatment with 30 mM KCl for 18 hours. The expression of Shank3a, 3c, 3d, and 3e was significantly reduced while no change was observed for Shank3b. (B) Western blot showed reduced Shank3 proteins after KCl treatment. (C) Quantification for Shank3 proteins in (B) . (D) Splicing of Shank3 isoforms after KCl treatment. Alternative splicing for E10-12S III-IV (E), E18S II of Shank3e (F), and E18S IV of Shank3e-1 (G) were increased after KCl treatment. All data are shown as mean ± SEM. *P <0.05, #P <0.002, ^P <0.001, compared to control group, two tail t-test, n = 4 each group.