SDS-PAGE and Western Blot Analysis

Proteins were separated by standard SDS-PAGE using the NuPAGE® system (Invitrogen, Carlsbad, CA, USA), followed by a transfer to PVDF membranes (Millipore, Billerica, USA). To improve the detection of endogenous α-synuclein of H4 cells, the membranes were fixed with 0,4 % PFA prior blocking as described previously [57 (link)]. Following antibodies were used: rabbit-anti-β-actin, (1:2000, Sigma, St. Louis, USA or 1:1000, abcam, Cambridge, UK), mouse-anti-α-synuclein (4B12, 1:3000, Covance, Princeton, USA), mouse-anti-α-synuclein (LB-509, 1:1000, Covance, Princeton, USA), rabbit-anti-SOD1 (ADI-SOD-100, 1:2000, Enzo life science, New York, USA), sheep-anti-SOD1 (1:1000, Calbiochem, Farmingdale, USA), HRP coupled secondary antibodies (1:1000, Life Technologies, Carlsbad, USA, or SouthernBioTech, Birmingham, USA).