PRKN and prion disease: Next, we overexpressed (Fig. S6A, B, The level of Parkin in Parkin-overexpressed cells was increased by about 81%) and suppressed (Fig. S6C, D, The level of Parkin in Parkin knockdown cells was reduced by about 52%) the PINK1 downstream effector molecule parkin, an important mitophagy signal amplifier in the PINK1-parkin pathway [19], and used mitophagy inducers UA (50 μM) and NMN (2.5 mM) to verify their effects on mitophagy in prion disease.