Extended Data Fig. 2: Mass spectrum of (a) the proteoform library obtained from hippocampal-specific PiMS experiment and (b) aggregated 5272-cell dataset I with proteoform annotations.
From: Proteoform profiling of endogenous single cells from rat hippocampus at scale
Mass spectrum of (a) the proteoform library obtained from hippocampal-specific PiMS experiment (a 2.5 mm by 2.5 mm hippocampal region of a 10-micron thin brain section with a total of 38 million ions and 15930 MS scans) and (b) aggregated 5272-cell dataset I with annotations of the 165 identified proteoforms in Supplementary Data 5.5 and the 23 MS/MS-identified proteoforms in Supplementary Data 4. The inset in (a) shows the detailed annotation of MBP (P02688-4) proteoforms at ~14.1 kDa. The proteoforms labeled in gray are abundant proteins found in hippocampal tissues but not part of the hippocampal-enriched biological pathways, therefore they were not included in the IMT database and not used for subsequent cell typing effort. However, these proteoforms were identified using our MS/MS approach and were confirmed to be ubiquitously-expressed brain proteins (for example, ubiquitin, ATP synthase subunits-ATP5E, myelin basic proteins-MBPs, brain acid soluble protein-BASP1) that only have a minor contribution to cell type classification of neurons and glial cells.
