MAPT and Alzheimer disease: These strategies have targeted what are known as the hallmarks of AD, amyloid-β (Aβ) plaques and hyperphosphorylated microtubule-associated protein tau (MAPT, or tau) aggregates (Franco and Cedazo-Minguez, 2014; Tai et al., 2015; Elmaleh et al., 2019; Tzioras et al., 2019), but a mechanistic understanding of how the progression of these pathologies leads to neuron death and cognitive decline is lacking.