Fig. 1.

CaMKIIβ controls spine morphology and is phosphorylated at S315 in Purkinje cells. (A) Effects of overexpression of WT or K43M mutant form of HA-tagged CaMKIIβ on Purkinje cell dendritic spine morphology in cerebellar slice cultures. Cerebellar slices were subjected to biolistic cotransfection with HA-CaMKIIβ and EGFP, cultured for 2 d, and immunostained with anti-EGFP and HA antibodies. Representative images of distal dendrites of Purkinje cells are shown. (Scale bar, 2 μm.) (B) Quantitative analysis of spine density along distal dendrites (Left), spine length (Center), and spine head width (Right) of EGFP⁺ Purkinje cells in A. **P < 0.01, ***P < 0.0001, one-way ANOVA with Bonferroni’s test for multiple comparisons. (C) Summary of in vivo phosphorylation sites of CaMKIIβ in Purkinje cells. Phosphorylation sites are depicted as “P.” The critical F-actin binding region (317–340 aa) is underlined. Detailed information is provided in Fig. S1. (D) Conservation of S315 (in red) in CaMKIIβ among species. Calmodulin (CaM) binding domain and β_e splicing site of CaMKIIβ are also shown. Each amino acid sequence is from accession numbers NP_031621.3 (Mus musculus), NP_068507.2 (Rattus norvegicus), NP_742075.1 (Homo sapiens), NP_001084063.1 (Xenopus laevis), NP_989625.1 (Gallus gallus), or XP_009303979.1 (Danio rerio). The numbers of neurons or spines are indicated in each graph.