DKK1 and Alzheimer disease: Aβ has not only been shown to activate Wnt-PCP signaling through Dkk1 (Bafico et al., 2001; Sellers et al., 2018), but also to increase mTOR activity in 3xTg AD mice brain regions with high levels of intraneuronal Aβ (Caccamo et al., 2010; Caccamo et al., 2011).