Fig. 1
Schematic diagram of the cPRISM-SRM workflow. A small number of cells are isolated either by serial dilution or cell sorting and collected into a container with large amounts (~50 µg) of carrier proteins to prevent undesired sample loss. Commonly used digestion protocols are used for sample processing to generate tryptic peptides without any further modification. After digestion and sample cleanup heavy isotope-labeled internal standards are added to the peptide mixtures. Highly sensitive PRISM-SRM is then used for precise quantification of surrogate peptides from proteins of interest with reducing the significantly increased dynamic concentration range caused by the addition of carrier proteins. The freely-available open-source Skyline software is used for SRM data analysis
