MAPT and neurodegenerative disease: In contrast to the normal physiological condition in which tau has a stable and unfolded monomeric conformation, in pathological conditions, tau is phosphorylated or hyperphosphorylated and self-aggregates, resulting in pathogenic conformations in neurodegenerative diseases, termed tauopathies.[7,84] The roles of tau in physiological and pathological conditions in the cell are summarized in Figure 1.