MAPT and Alzheimer disease: This change on Sirt1 levels could underlie alterations on lysosome degradation processes, which is also supported by observations in the brain of Alzheimer’s disease patients, where a deficiency in SIRT1 leads to hyperacetylation of the phosphorylated tau, resulting in impaired tau degradation by the 26S proteasome [146] and by autophagy [147].