Abnormal calcium storage and release from the SER is evident in both sporadic and inherited AD,62 in which high levels of cytosolic calcium drive calpain‐2‐mediated disinhibition of GSK3β and cdk5 to hyperphosphorylate tau,21, 63, 64, 65 including at pT217‐tau.66 Here, GSK3B is linked to Alzheimer disease.