MAPT and Alzheimer disease: Notably, in the TEM images of D-TLKIVWX (X = I, S, R, D, E, K, T, C, A and V)-treated AD-tau samples (Fig. 1c and Extended Data Fig. 1c), we also observed the emergence of new fibrils (labeled by blue arrows) accompanying with the disappearance of AD-tau fibrils.