Figure 3

Al³⁺promotes stronger formation of SDS stable tau and α-syn coaggregates than Fe³⁺, preferably after tau phosphorylation. A. Cross-correlation amplitudes (G (0)) show mild proaggregatory activity of DMSO and Fe³⁺, while Al³⁺ promotes intense protein oligomerization. Combinations of DMSO and metal ions show a synergistic effect especially for mTau. 2D histograms show the formation of smaller oligomers induced by DMSO compared to Al³⁺. B. Cross-correlation amplitude before (T₀) and 100 min after (T₁₀₀) addition of SDS to the aggregation assay. Significant reductions of aggregation levels at T₁₀₀ are indicated by the symbols over the error bars, while significant differences between pTau and mTau are indicated by the symbols over the wide bars. C. Cross correlation amplitude at T₁₀₀ normalized against T₀ shows increased SDS-resistance of metal ion induced oligomers compared to DMSO. D. Scheme illustrating the appearance of tau and α-syn aggregates and coaggregates of the two proteins. Higher fluorescence intensities of detected oligomers indicate increased oligomer size. Measurements were taken from 16 independent samples; each sample was measured four times. Levels of significance are displayed as * = p < 0.05; ** = p < 0.01; ‡ = p < 0.001.