Thesaurus: quantifying phosphopeptide positional isomers

Nat Methods. 2019 Aug;16(8):703-706. doi: 10.1038/s41592-019-0498-4. Epub 2019 Jul 29.


Proteins can be phosphorylated at neighboring sites resulting in different functional states, and studying the regulation of these sites has been challenging. Here we present Thesaurus, a search engine that detects and quantifies phosphopeptide positional isomers from parallel reaction monitoring and data-independent acquisition mass spectrometry experiments. We apply Thesaurus to analyze phosphorylation events in the PI3K/AKT signaling pathway and show neighboring sites with distinct regulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • HeLa Cells
  • Humans
  • Insulin Receptor Substrate Proteins / metabolism
  • Isomerism
  • MCF-7 Cells
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphopeptides / analysis*
  • Phosphoproteins / analysis*
  • Phosphorylation
  • Proteome / analysis*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Search Engine / methods*
  • Signal Transduction
  • Tandem Mass Spectrometry


  • IRS1 protein, human
  • Insulin Receptor Substrate Proteins
  • Phosphopeptides
  • Phosphoproteins
  • Proteome
  • Phosphatidylinositol 3-Kinases
  • AKT1 protein, human
  • Proto-Oncogene Proteins c-akt