MAPT and Alzheimer disease: However, the underlying mechanisms of AD are still poorly understood, which may be attributed to the complex multipathogenic features4,5, including amyloidogenic processing of amyloid precursor protein (APP), Aβ aggregation, tau hyperphosphorylation, calcium dyshomeostasis, oxidative stress, mitochondrial dysfunction, deterioration of synaptic neurotransmission, and neuronal apoptosis.