Sarkosyl-insoluble fractions were extracted from cases neuropathologically diagnosed as Alzheimer’s disease (AD), PiD, PSP or CBD (AD-tau, PiD-tau, PSP-tau, CBD-tau) and introduced into SH-SY5Y cells transiently expressing HA-tagged 3R tau with 1N insert (HA1N3R) or HA-tagged 4R tau with 1N insert (HA1N4R) (Table 1 and Supplementary Fig. 1). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.