Using nanopore based sensors, Giamblanco et al. (2020) monitored tau protein during heparin induced fibrilization, comparing the FTD associated P301L tau isoform to wild type tau, and found that the P301L mutation promoted the assembly of tau monomers into oligomers, and the dissociation of tau fibrils into oligomers. Here, MAPT is linked to frontotemporal dementia.