Analysis of the inclusions in intact TauRD-Y* cells by cryo-electron tomography (Supplementary Fig. 2a) revealed TauRD-Y fibrils of ~18 nm diameter, which were distinguishable from cytoskeletal structures (Fig. 1d) and consistent with the structures of fibrillar Tau in tauopathy patient brain44–48. Here, MAPT is linked to tauopathy.