Seeded polymerization and template-directed misfolding
Prion and amyloid aggregation follows nucleation-polymerization kinetics: monomers (M) first form unstable nuclei (rate k_n), which then elongate by recruiting free monomers (rate k_e). The sigmoidal aggregation curve is a hallmark of this mechanism — a lag phase dominated by slow nucleation, followed by rapid fibril growth. Seeding bypasses the lag phase entirely, explaining prion infectivity.