Temporal Trajectories of the Tau Aggregate Interactome Reveal Stage‐Specific Vulnerabilities in Alzheimer's Disease

Abstract

ABSTRACT Tau aggregation is a central pathological feature of Alzheimer's disease, yet how different forms of tau—ranging from monomers to small soluble aggregates and mature fibrils—interact with the cellular environment remains poorly understood. Here, we combine immunoaffinity proteomics with single‐molecule techniques and super‐resolution microscopy to systematically map the tau interactome across defined aggregation states, spanning monomeric tau, nanoscopic soluble aggregates, and fibrillar species. Using post‐mortem Alzheimer's disease brain tissue, we identify distinct functional modules associated with different aggregation states: while proteostasis factors and immune‐related proteins preferentially associate with nanoscopic aggregates (oligomers), cytoskeletal, metabolic, and RNA‐binding proteins are enriched for mature fibrillar tau. Single‐molecule microscopy directly confirms this conformation‐dependent recruitment for key interactors including Hsp70‐2, ENO1, hnRNPA1, APP, EAAT4, and ubiquitin. A primary‐neuron system with accelerated tau aggregation is used to model these findings in a controlled system, showing striking similarities to the brain samples. Finally, pseudotime analysis reconstructs a progressive remodelling of the tau interactome across disease progression, revealing stage‐specific pathway vulnerabilities. Together, these results establish a temporally resolved framework for tau pathology shaped by protein interactions and identify potential therapeutic intervention points for investigation across stages of disease.