Phosphorylation of tau protein at sites <scp>Ser</scp>^396–404 is one of the earliest events in <scp>A</scp>lzheimer's disease and <scp>D</scp>own syndrome

Phosphorylation of tau protein at the carboxyl terminus may be among the earliest tau events, and it occurs prior to the apparition of the classical fibrillar structure. Finally, these data validate PHF-1 as an efficient marker for AD cytopathology following the progression of tau aggregation into NFT.