Amyloid-motif-dependent tau self-assembly is modulated by isoform sequence context

The microtubule-associated protein tau is implicated in neurodegenerative diseases characterized by amyloid formation. Mutations associated with frontotemporal dementia increase tau aggregation propensity and disrupt its endogenous microtubule-binding activity. However, the structural relationship between aggregation propensity and biological activity remains unclear. We employed a multi-disciplinary approach, including computational modeling, NMR, cross-linking mass spectrometry, and cell models to engineer tau sequences that modulate its structural ensemble. Our findings show that substitutions near the conserved 'PGGG' β-turn motif informed by tau isoform context reduce tau aggregation in vitro and cells and can even counteract aggregation promoting disease-associated proline-to-serine mutations. Engineered tau sequences maintain microtubule binding and explain why 3R isoforms exhibit reduced pathogenesis compared to 4R. We propose a simple mechanism to reduce the formation of pathogenic species while preserving biological function, thus offering insights for therapeutic strategies aimed at reducing tau protein misfolding in neurodegenerative diseases.

Description of Source Data and Supplementary Data: All MD, NMR (peptide and tauRD), ThT, XL-MS, MT stabilization, MT:tau modeling, and cell-based aggregation data are available in the Source_Data directory as Source Data 1, Source Data 2, Source Data 3 and 4, Source Data 5, Source Data 6, Source Data 7, and Source Data 8, respectively. Supplementary Data for raw MD trajectory files, structure files for MSM modeling and validation file, and tau:MT modeling are available as "Supplementary_Data_MD_Trajectories_Structures", "Supplementary_Data_MSM_models_Structures" and "Supplementary_Data_MT-tau_complex_models", respectively."