The present invention provides materials and methods for treating Alzheimer's disease and other tau related neurodegenerative disorders. A tau kinase, Brain Derived Tau Kinase (BDTK) is provided. BDTK can cause hyperphosphorylation of tau protein, which leads to formation of neurofibrillary tangles, which are implicated in the degenerative symptoms of Alzheimer's and other neurodegenerative disorders. Methods of diagnosis and treatment based on the discovery of this novel tau kinase are also provided.