Prion-like spread of disease-specific tau conformers is a hallmark of all
tauopathies. We used a 19-residue probe
peptide spanning the R2/R3 splice junction of tau to induce aggregation specifically of 4R, but not 3R tau. The aggregates can propagate as
isoform-specific seeds over multiple generations, have a high β-sheet content, a
lipid signal, and resemble the PSP cryo-EM fold. A simulation of
peptide free energy landscapes pinpointed the features of the hairpin structure uniquely found in the cryo-EM structures of pure 4R
tauopathies and captured in the
peptide. These molecular dynamic simulations were experimentally validated by the S305K substitution in 4R tau, corresponding to the position found in 3R tau. This single amino acid substitution prevented tau aggregates induced by the
prion-like probe
peptide. The tau aggregates were dynamic and displayed growth, stability, and shrinking over time. These results could serve as the basis for tau
isoform-specific therapeutic interventions.