Extended Data Fig. 2: Synaptic tau colocalises with synaptogyrin-3 in PSP frontal cortex.

a,b, Segmented array tomography images. Array tomography ribbons were stained for synaptophysin (cyan), synaptogyrin-3 (magenta) and tau (yellow). Representative images of maximum intensity z-projections of 5 serial sections are shown for a control (a) and a PSP case (b). The top row of each panel contains a 50 × 50 μm region of interest with a 10 μm scale bar, and the bottom rows contain a zoomed-in 10 × 10 μm region of interest with a 2 μm scale bar. The far-right column shows three-dimensional reconstructions of 5 serial sections. An arrow indicates a synapse containing tau in the PSP case. c–f, Quantification of segmented array tomography images reveals increases in the percentage of synaptogyrin-3 puncta containing tau (c, ANOVA after linear mixed effects model on Tukey transformed data ~ diagnosis + (1 | case/block) estimate = 0.279, 95% CI (0.004, 0.553), t(11.68) = 2.25, p = 0.044), synaptophysin puncta containing tau (d, estimate = 0.206, 95% CI (0.000037, 0.413), F(11.1) = 5.0167, p = 0.047) and increased tau burden (e, estimate = 0.427, 95% CI (0.251, 0.603), F(17.1) = 32.789, p < 0.0001). Tau burden positively correlates with the percentage of synaptogyrin-3 puncta containing tau in PSP but not control cases (f). Boxes show quartiles and medians calculated from each image stack, and whiskers show minima and maxima excluding outliers (n = 7 control, 7 PSP cases, 1–2 blocks per case, 2–3 stacks per block, group comparison statistics with linear mixed effects model). Correlations with Pearson’s correlation test. Data points refer to case means (females, circles; males, triangles).