GSK3A and tauopathy: p-CDK5 and p-GSK3α/β levels in the hippocampus did not differ between AAV-DYRK1A shRNA-injected and AAV-control shRNA-injected PS19 mice (Figures 8G, H), suggesting that DYRK1A knockdown directly in the brain in human tau mutant PS19 mice selectively suppresses tauopathy-associated phosphorylation without altering levels of the tau kinases CDK5 and GSK3α/β.