PP2A accounts for ~71% of total tau phosphatase activity in the human brain (Liu et al., 2005); and its expression and/or activity have been found significantly decreased under the conditions of AD pathology (see Lambrecht et al., 2013; Taleski and Sontag, 2018 for further references), which should promote hyperphosphorylation of Tau by disturbing the balance between Tau kinase and phosphatase activities mentioned above. Here, PTPA is linked to Alzheimer disease.