PIN1 and Alzheimer disease: First, we hypothesized that cis P-tau is pathogenic in AD, because pT231-Tau (P-tau) is induced at early stages of AD and Pin1 −/− mice conferred age-dependent tauopathy and neurodegeneration (Liou et al., 2003; Pastorino et al., 2006; Cancino et al., 2013).