Fig. 1.

Nucleated polymerization model with a single prion strain, illustrated with a nucleus size of $x_0=3$. The normal form monomers (empty circles) appear with a production rate $\lambda$ and are degraded with a rate $\gamma$. They are recruited by prion aggregates (crossed circles) with rate $\tau$. Each link in an aggregate may break with probability $\beta$, and an aggregate below the nucleus size $x_0$ is disassembled into normal monomers. The aggregates are degraded with rate $\mu$