MAPT and Alzheimer disease: Another main player in AD pathophysiology is the tau protein that undergoes hyperphosphorylation by specific Aβ-activated kinases, including glycogen synthase kinase-3β (GSK-3β), cyclin-dependent kinase 5 (cdk5), and dual specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A) [39,40,41,42].