Mass spectrometry analyses identify OTUB1 as an α-synuclein-interacting protein, with its oligomeric and fibrillar forms elevating both total α-synuclein and pathological pS129-α-synuclein levels in SH-SY5Y cells, thereby exacerbating PD pathology (Kumari et al. 2020, 2022). Here, OTUB1 is linked to Parkinson disease.