Target discovery in small-molecule cell-based screens by in situ proteome reactivity profiling

Nat Biotechnol. 2005 Oct;23(10):1303-7. doi: 10.1038/nbt1149. Epub 2005 Oct 2.


Chemical genomics aims to discover small molecules that affect biological processes through the perturbation of protein function. However, determining the protein targets of bioactive compounds remains a formidable challenge. We address this problem here through the creation of a natural product-inspired small-molecule library bearing protein-reactive elements. Cell-based screening identified a compound, MJE3, that inhibits breast cancer cell proliferation. In situ proteome reactivity profiling revealed that MJE3, but not other library members, covalently labeled the glycolytic enzyme phosphoglycerate mutase 1 (PGAM1), resulting in enzyme inhibition. Interestingly, MJE3 labeling and inhibition of PGAM1 were observed exclusively in intact cells. These results support the hypothesis that cancer cells depend on glycolysis for viability and promote PGAM1 as a potential therapeutic target. More generally, the incorporation of protein-reactive compounds into chemical genomics screens offers a means to discover targets of bioactive small molecules in living systems, thereby enabling downstream mechanistic investigations.

Publication types

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

MeSH terms

  • Antineoplastic Agents / administration & dosage*
  • Antineoplastic Agents / pharmacokinetics
  • Biological Assay / methods*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Drug Delivery Systems / methods*
  • Drug Design
  • Humans
  • Phosphoglycerate Mutase / antagonists & inhibitors
  • Phosphoglycerate Mutase / metabolism*
  • Protein Interaction Mapping / methods*
  • Proteome / metabolism*


  • Antineoplastic Agents
  • Proteome
  • Phosphoglycerate Mutase
  • phosphoglycerate mutase 1, human