Figure 4.

Nucleation and growth are both dependent on dimeric tau protein. Monomeric tau (20 μM; K12^A322) or 10 μM dimeric tau (K12 crosslinked via disulfide linkage of Cys³²²) was incubated in assembly buffer with 5 μM heparin in the absence or presence of seeds (corresponding to 1 μM tau protein). The time course of assembly shows that seeding accelerates assembly in both cases. Note that dimeric K12 without seeds is even faster than monomeric K12A³²² in the presence of seeds, illustrating a high tendency of dimeric tau to self-assemble. The final extent of assembly is the same in all cases.