Fig. 7.

Lithium concentration-dependently inhibits GSK3β activity. GSK3β activity was measured by immunoprecipitating GSK3β from serum-starved (24 h) wild-type (wt) and GSK3β-overexpressing SH-SY5Y cells, incubating the immunoprecipitated GSK3β with recombinant human tau, [³²P]ATP, and lithium, and measuring the phosphorylation of tau, as described in Materials and methods. Shown is a representative autoradiograph from an experiment with GSK3β-overexpressing cells, and quantitative values from both cell types expressed as the percent of GSK3β activity in the respective celltype in the absence of lithium, and values from GSK3β-overexpressing cells also are shown expressed as the percent of GSK3β activity in wild-type cells. Mean ± SEM, n = 3 experiments.