Fig. 4.
Synaptojanin 1 is a substrate for calcineurin, and its dephosphorylation by calcineurin increases its 5-phosphatase activity. (A) Purified synaptojanin 1 (Upper) or dynamin 1 (Lower) were first phosphorylated by p35/Cdk5 in the presence of [γ-32P]ATP, then further incubated with calcineurin, and finally analyzed by SDS/PAGE and autoradiography. (B) Immunoprecipitates generated from rat brain extracts with control IgG and anti-synaptojanin 1 antibody were incubated with calcineurin and then analyzed for 5-phosphatase activity by TLC as described in the legend of Fig. 3A. Anti-synaptojanin 1 Western blotting (Upper) indicates that the similar amount of synaptojanin 1 was present in the “plus” and “minus” calcineurin assay conditions. (C) Pooled results of 5-phosphatase activity assays as described in the legend of Fig. 3B.