MAPT and Alzheimer disease: Another means by which tau mediates MT stability is its role in protecting MTs from the enzymatic severing by katanin (Kempf et al., 1996; Qiang et al., 2006), a process that is thought to be impacted upon in AD and tauopathies, due to the loss of tau-MT localization when tau is phosphorylated (Sudo and Baas, 2011).