Tau hyper-phosphorylation and some AD-like features can be caused or exacerbated by experimental manipulation of PP2A activity, for example using PP2A-inhibiting chemicals (Gong, Wang, Iqbal, & Grundke-Iqbal, 2003; Kamat, Rai, & Nath, 2013), over-expression of DNA tumor virus T antigens (Sontag, Nunbhakdi-Craig, Lee, Bloom, & Mumby, 1996) or PP2A inhibitory proteins (Wang, Blanchard, Tung, Grundke-Iqbal, & Iqbal, 2015), introduction of a dominant negative catalytic subunit (Deters, Ittner, & Gotz, 2009) or inhibition of PP2CA methylation (Sontag, Nunbhakdi-Craig, & Sontag, 2013). Here, PTPA is linked to Alzheimer disease.