Serva native marker

For BN‐PAGE, samples extracted as detailed above were diluted as per the manufacturer's instructions by adding NativePAGE 5% G‐250 sample additive, 4x Sample Buffer and water. After dilution, samples were loaded and run on Native PAGE 3–12% Bis‐Tris gels alongside either NativeMark unstained protein standard (Invitrogen) or SERVA Native Marker (SERVA). The proteins were then transferred to polyvinylidene difluoride membranes using NuPAGE Transfer Buffer using a Trans‐Blot Turbo Transfer System (Bio‐Rad) as per the manufacturer's instructions. Proteins were fixed to the membranes by incubating with 8% acetic acid for 15 min, washed with water and left to dry. Membranes were subsequently re‐activated with methanol in order to correctly visualize the unstained native protein marker. Membranes were immunoblotted as described below.

For BN-PAGE, samples extracted as detailed above were diluted as per the manufacturer’s instructions by adding NativePAGE 5% G-250 sample additive, 4× sample buffer, and water. After dilution, samples were loaded and run on NativePAGE 3 to 12% bis-tris gels alongside either NativeMark unstained protein standard (Invitrogen) or SERVA Native Marker (SERVA). The proteins were then transferred to polyvinylidene difluoride membranes using the NuPAGE Transfer Buffer using a Trans-Blot Turbo transfer system (Bio-Rad) as per the manufacturer’s instructions. Proteins were fixed to the membranes by incubating with 8% acetic acid for 15 min, washed with water, and left to dry. Membranes were subsequently reactivated with methanol to correctly visualize the unstained native protein marker. Membranes were immunoblotted as described below.

Blue native‐PAGE was performed as indicated by the manufacturer. Protein extracts and immunoprecipitation (IP) eluates were added with 4× NativePAGE™ Sample Buffer (Invitrogen™, BN2003) and NativePAGE™ 5% G‐250 Sample Additive (Invitrogen™, BN2004) to a final concentration of 0.125%. Then, samples were loaded on NativePAGE™ Novex® 3–12% Bis‐Tris Gels (Invitrogen™, BN1001) and run at 150 V in cathode buffer containing Coomassie G‐250 (by adding NativePAGE™ Cathode Buffer Additive to 1/200 dilution, Invitrogen™, BN2002 to NativePAGE™ Running Buffer, Invitrogen™, BN2001). NativeMark™ Unstained Protein Standard (Invitrogen™, LC0725) or SERVA Native Marker (SERVA, 39219.01) were loaded to predict the size of detected protein species.