The ease of making AD PHFs and CTE tau filaments in vitro with recombinant tau proteins opens new avenues for tauopathies research such as understanding the molecular mechanisms of amyloid formation, small molecule drug screening, filament-specific diagnostic ligand development for positron emission tomography, or special binding agent development to couple the protein degradation machinery aiming to degrade toxic tau filaments inside neurons as potential AD therapy. Here, MAPT is linked to Alzheimer disease.