In addition to abnormal phosphorylation, tau protein in neurodegenerative disease brain can be modified in a number of ways, including N- and C-terminal proteolytic cleavage, altered conformation, nitration, glycosylation, acetylation, glycation, ubiquitylation, O-GlcNAcylation, aggregation, and filament formation (45, 46). Here, MAPT is linked to neurodegenerative disease.