APP and Alzheimer disease: The MAPK signaling pathways have been implicated in AD pathogenesis through divergent mechanisms including induction of neuronal apoptosis18, 19, 20 and phosphorylation of amyloid precursor protein (APP) and tau, which influence the cleavage of APP to generate amyloid-β (Aβ) and the formation of neurofibrillary tangle (NFT)s, two hallmarks of AD19, 21.