FIGURE 4.

Phosphorylation of IP₃Rs in cerebellum microsomes by Akt kinase in the presence and absence of Ca²⁺. Cerebellum microsomes were phosphorylated with [γ-³²P]ATP and recombinant Akt kinase in the presence or absence of 2.2 μm Ca²⁺ as described under “Experimental Procedures.” After 2 h at 30 °C, the membranes were lysed and immunoprecipitated with CT-1 Ab. The immunoprecipitates were analyzed for radioactivity by phosphorimaging and for IP₃R levels by immunoblotting. The fold increase in radioactivity was quantitated and is shown as mean ± S.E. for three experiments.