Fig. 4

Schematic structure of tau and α-synuclein proteins. a Tau protein contains three main domains: an N-terminal domain (red/pink), a proline-rich domain (blue), and a microtubule-binding domain (orange). Tau isoforms can range between 352 and 441 amino acids in length; containing zero, one, or two N-terminal repeats (encoded by exons 2 and 3—shown in dark red), and three or four C-terminal microtubule-binding domains (presence or absence of R2, encoded by exon 10)—which define the 3R and 4R tau species. b In contrast, α-synuclein is a relatively short protein (140 amino acids in length), but can also be divided into three regions: an N-terminal domain (green), a non-amyloid-component (NAC) region (yellow), and a C-terminal domain (purple), with each of their correspondent functions shown