Assays

For proteomic analysis, iPSC-derived neural stem cells at day 15 of culture were treated with 3.3 uM Nocodazole (Sigma) or same volume of DMSO (control) before being washed with ice-cold PBS, scrapped and centrifuged for 10 min at 300 g before lysis in Buffer A, containing 50 mM Tris-HCL (pH 7.5), 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, 1% Triton-X100, 0.1% SDS, protease inhibitor (Pierce), at a volume twice that of the pellet. For neurons, day 40 of cultures treated only with DMSO were used. Samples ...

APEX2-mediated biotinylation of cells was carried out as described before (Hung et al., 2016). In brief, cells were supplemented with 500 µM biotin-phenol (IrisBiotech) for 30 min at 37°C before addition of 1 mM H2O2 at room temperature. Cells were then first washed with quencher solution (1 mM sodium azide, 10 mM sodium ascorbate and 5 mM Trolox in DPBS), then with DPBS, scraped and harvested. All steps were carried out at 4°C unless stated otherwise. Cells were washed and suspended in homogenization ...

Proximity-proteomics-based autophagosome content profiling to identify a role for LC3C in maintaining basal mitochondrial homeostasis. Selected mitochondrial proteins, including MTX1, were targeted by LC3C and p62 through a piecemeal mitophagy pathway. SILAC cells biotinylated using APEX proximity labeling. Cell lysates treated with protease. RIPA soluble and insoluble fractions were subjected to Streptavidin pulldown followed by in gel digestion. 4 lanes were cut from one sample.

Total protein content of CSF samples was measured by Bradford assay (BioRad, Feldkirchen, Germany)and 10μg per sample were proteolysed by the commercially available in-StageTip-NHS kit (PreOmics GmbH, Martinsried, Germany) according to the manufacturer's protocol. Briefly, CSF was reduced and alkylated and incubated for 3 hrs at 37°C with Lys-C and trypsin. Resulting peptides were dried for short term storage at -80°C. Prior to measurement, peptides were resuspended in 2% acetonitrile and 0.5% ...