Overview:

Alzheimer’s Disease (AD) is the most common neurodegenerative disease, affecting 10% of seniors over the age of 65 (1). It was named after Alois Alzheimer, a German scientist who discovered tangled bundles of fibrils where neurons had once been in the brain of a deceased patient in 1907 (2). Tau (tubulin-associated unit) is normally located in the axons of neurons where it stabilizes microtubules. Tauopathies such as AD are characterized by neurofibrillary tangles containing paired helical filaments (PHFs). A truncated 95-amino acid fragment corresponding to residues 297-391 of full-length tau has been shown to assemble into PHF-like fibrils in vitro in the absence of additives or templates (3). This fragment has been found in the core of PHFs from AD brains and forms filaments that closely resemble PHFs isolated from AD brains (3).

References:

1. www.alz.org/alzheimers-dementia/facts-figures
2. Alzheimer, A. Über eine eigenartige Erkrankung der Hirnrinde. Allg. Z. Psychiatr. Psych.-Gerichtl. Med. 64, 146–148 (1907)
3. Al-Hilaly, Y.K. et al. Alzheimer's Disease-like Paired Helical Filament Assembly from Truncated Tau Protein Is Independent of Disulfide Crosslinking. J. Mol. Biol. 429(23):3650-3665 (2017)