Fig. 4

Measuring global protein half-lives in cultured human i³Neurons. A Schematic of dSILAC proteomics to measure global protein half-lives in cultured human i³Neurons. Cortical neurons were grown in normal medium until day 10 and then switched to heavy lysine-containing medium. Neurons are harvested at 1, 2, 4, and 6 days after medium switch followed by bottom-up proteomics. B Time-dependent changes of relative light and heavy protein abundances indicating protein degradation and synthesis processes, respectively, in WT i³Neurons. C Scatter plot of ranked protein half-lives measured in WT i³Neurons. D Histogram distribution of protein half-lives in WT i³Neurons. An example cathepsin B (CTSB) protein with five unique peptide sequences is illustrated in the inset. E GO enrichment analysis of the fast (left) and slow (right) turnover proteins in WT i³Neurons. F Violin plots of half-life distributions from lysosomal proteins in WT i³Neurons