Tau is the prime participant in the Alzheimer's disease (AD) neurodegeneration: AD, the main cause of dementia in elderly people, is a multifactorial neurodegenerative disorder characterized by a long prodromal phase (starting more than two decades before clinical symptoms appear) with brain accumulation/misfolding of amyloid β (Aβ) in insoluble amyloid plaques and of tau protein in neurofibrillary tangles.