Fig. 12

Syk activation (Y525/526) influences the level of tau oligomerization (TOC1). Sections from Tg Tau P301S (n = 4, 47 ± 3.1-week-old) stained with antibodies against tau oligomers (TOC1, purple) and pSyk (Y525/526, green). Fluorescent intensities of oligomerized tau (TOC1) and pSyk were measured using Zen Blue 2.1 (Zeiss). Three different neuronal fractions were differentiated: a) neurons singly immunopositive for TOC1, (b) neurons singly immunopositive for pSyk and (c) neurons immunopositive for both (colocalized). d Fluorescent intensities of TOC1 were compared between neurons singly immunopositive for TOC1 (purple) and neurons exhibiting a colocalization of pSyk and TOC1 (purple-green-striped). Two-tailed Mann–Whitney test revealed a significant increase (p < 0.0001) of TOC1 fluorescent intensity in neurons exhibiting a colocalization with pSyk compared to singly TOC1 immunopositive neurons. e Fluorescent intensities of pSyk were compared between neurons singly immunopositive for pSyk (green) and neurons exhibiting a colocalization pf TOC1 and pSyk (purple-green-striped). Two-tailed Mann–Whitney test revealed no significant change of pSyk fluorescent intensity in neurons exhibiting a colocalization compared to the singly pSyk immunopositive neurons. The scale bar represents 10 μm. The error bars represent SEM