Fig. 1.

Three schematics describing different ways of considering the relationship between monomer, denoted by the letter M (blue dispersed circles), irregular/amorphous aggregate, denoted by the letter I (green aggregates) and amyloid, denoted by the letter A (yellow fibers). (TOP) Amyloid in direct competition with amorphous aggregate for monomer. (MIDDLE) Amorphous aggregate as an obligate intermediate in the formation of amyloid. (BOTTOM) Amorphous aggregate as a potential, but not obligatory intermediate, in the formation of amyloid. (Translated and reprinted with full permission from Hirota and Hall (2019), CMC Publishing Corporation)