Fig. 10

Tau phosphorylation at Y18 and Syk activation (Y525/526) cross-influence each other. Sections from Tg Tau P301S (n = 4, 47 ± 3.1-week-old) were stained with antibodies against phosphorylated tau (Y18, purple) and pSyk (Y525/526, green). Fluorescent intensities of pTau (pY18) and pSyk were measured using Zen Blue 2.1 (Zeiss). Three different neuronal fractions were differentiated: a neurons singly immunopositive for pY18, (b) neurons singly immunopositive for pSyk and (c) neurons immunopositive for both (colocalized). d Fluorescent intensities of pY18 tau were compared between singly pY18 immunopositive and the double immunopositive neurons (colocalized, purple-green-striped). Two-tailed Mann–Whitney test revealed a significant increase (p < 0.05) of pY18 fluorescent intensity for neurons exhibiting a colocalization compared to the neurons singly immunopositive for pY18 tau. e Fluorescent intensities of pSyk were compared between singly pSyk immunopositive neurons (green) and double immunopositive neurons for pSyk and pY18 tau (purple-green-striped). Two-tailed Mann–Whitney test revealed a significant increase (p < 0.01) of pSyk fluorescent intensity in neurons double immunopositive for pSyk and pY18 tau compared to singly pSyk immunopositive neurons. The scale bar represents 10 μm. The error bars represent SEM