SUMOylation by SUMO1 increases α-synuclein aggregation in SH-SY5Y (Rott et al., 2017) and COS-7 cells (Oh et al., 2011) Preventing SUMOylation increases α-synuclein aggregation and toxicity in HEK293 cells and a PD rat model (Krumova et al., 2011) Artificially SUMOylated α-synuclein decreases fibrillation in vitro (Krumova et al., 2011; Abeywardana and Pratt, 2015) (See more details in Table 2). Here, SUMO1 is linked to Parkinson disease.