Abundant amyloid-like filamentous structures labelled with anti-HA, pS396 and TauC antibodies were observed in the insoluble fractions extracted from transfected cells expressing either HA-tagged 3R-FL or 4R-FL with introduced PiD-, PSP-, CBD- and AD-tau seeds (Fig. 6A and Supplementary Fig. 8, A). Here, OPN1MW is linked to Alzheimer disease.