In tauopathies, including AD, tau abnormalities???whether they are due to mutations in the tau gene or an altered 4R:3R tau ratio???cause brain deposition of highly phosphorylated tau in an aberrant conformation [79].Hyperphosphorylation of tau has been suggested to be caused by an imbalance between kinase and phosphatase activities within the neurons during the development of Alzheimer???s diseas