Figure 1.

Schematic illustration of the lifecycle of amyloid. (Circles) Soluble monomeric protein. (Parallelograms) Monomeric units in the amyloid cross-β conformation. (Colored arrows) Main processes in amyloid assembly. (Red arrows) Primary nucleation, which may occur as homogeneous nucleation in solution or heterogeneous nucleation at interfaces. (Purple arrow) Secondary nucleation, which may occur as heterogeneous nucleation at surfaces presented by preformed aggregates. (Blue and orange arrows) Key nonnucleation based processes elongation growth, and breakage division, respectively. (Single arrows may represent multiple consecutive steps; arrow thickness symbolizes relative rates involved in the processes.) To see this figure in color, go online.