MAPT and Alzheimer disease: STZ rats showed that tau protein was hyperphosphorylation at the 396 serine/threonine site, which is also found to be hyperphosphorylated in AD patients (Alonso, Zaidi, Novak, Grundke‐Iqbal, & Iqbal, 2001; Kosik, Orecchio, Bakalis, & Neve, 1989).