An optimized filter trap assay for detecting recombinant authentic tau fibrils

The development and optimization of the Filter Trap Assay (FTA) for the detection of authentic tau fibrils in vitro mark a pivotal advancement in the realm of tauopathy research, particularly by addressing the limitations of using polyanion-induced tau fibrils, which structurally differ from those isolated from tauopathy patients. Recently it has been shown that truncated tau fragment (297-391), also termed dGAE, can form authentic tau fibrils in the absence of polyanions. This study introduces a refined protocol that reliably detects authentic tau fibrils in a physiologically relevant framework, utilizing nitrocellulose membranes to achieve heightened sensitivity. Our investigation highlights the superior efficacy of sarkosyl, an anionic surfactant traditionally used to prepare protein lysates from brains and cultured neurons, in preserving the aggregated state of tau dGAE fibrils in vitro, underscoring its potential for further exploratory studies. By offering a user-friendly and economically feasible approach, this technique enables a broad range of laboratories to measure the presence of authentic tau fibrils. This methodological enhancement propels our understanding of tauopathies forward and bridges the gap between basic research and advanced structural analyses, enriching the scientific community's methodologies for studying neurodegenerative disorders.