A–C. Striatal or hippocampal low ionic strength Triton-soluble fractions were immunoprecipitated with either a spinophilin antibody and immunoblotted for spinophilin and CaMKII (A) or PP1 (B), or with a CaMKII antibody and immunoblotted for PP1 (C). D–F. Complexes isolated from striatal or hippocampal low ionic strength, Triton-soluble fractions using GSTSpN1, (E: amino acids 1–154), GSTSpN2 (F: amino acids 151–300), or GSTSpC1 (G: amino acids 665–817) and glutathione agarose were immunoblotted for CaMKIIα. Immunoreactivities were normalized to levels of GST protein isolated and to the levels of CaMKIIα in the input, and plotted as the striatum:hippocampus ratio on a Log10 scale (see Methods). Data were compared by an unpaired Student’s. **P<0.01, ***P<0.001, ****P<0.0001.