PIN1 and Alzheimer disease: Corresponding to the change in pS71-Pin1 levels, both the total tau and tau phosphorylation at AD-related sites, including Thr231, Ser262 and Ser396, were remarkably elevated in WT neurons incubated with Aβ42 species, whereas they were not affected by Aβ42 treatment in DAPK1 KO primary neurons (Figure 4A and B).