MAPT and Alzheimer disease: These investigations have not only unveiled the atomic-resolution structures of Aβ and tau protein fibrils in AD but, more significantly, have unequivocally demonstrated substantial commonalities in their core structures with PrPSc–specifically, the pervasive presence of the cross-β fold structure (Gremer et al., 2017; Jucker and Walker, 2018; Shi et al., 2021).