MAPT and early-onset autosomal dominant Alzheimer disease: Glycogen synthase kinase-3 beta (GSK3β), the main kinase that phosphorylates tau protein, is a component of the PI3K/AKT/mTOR signaling pathway, Increased expression of GSK3β can lead to hyperphosphorylation of tau protein via activation of mTOR, resulting in its aggregation and the formation of neurofibrillary tangles, which are a major neuropathological feature of Alzheimer’s disease [49–52].