Distinct and overlapping sets of SUMO-1 and SUMO-2 target proteins revealed by quantitative proteomics

Mol Cell Proteomics. 2006 Dec;5(12):2298-310. doi: 10.1074/mcp.M600212-MCP200. Epub 2006 Sep 25.


The small ubiquitin-like modifier (SUMO) family in vertebrates includes three different family members that are conjugated as post-translational modifications to target proteins. SUMO-2 and -3 are nearly identical but differ substantially from SUMO-1. We used quantitative proteomics to investigate the target protein preferences of SUMO-1 and SUMO-2. HeLa cells were established that stably express His6-SUMO-1 or His6-SUMO-2. These cell lines and control HeLa cells were labeled with stable arginine isotopes, and His6-SUMOs were enriched from lysates using immobilized metal affinity chromatography. 53 SUMO-conjugated proteins were identified, including 44 novel SUMO targets. 25 proteins were preferentially conjugated to SUMO-1, 19 were preferentially conjugated to SUMO-2, and nine proteins were conjugated to both SUMO-1 and SUMO-2. SART1 was confirmed by immunoblotting to have both SUMO-1- and SUMO-2-linked forms at similar levels. SUMO-1 and SUMO-2 are thus shown to have distinct and overlapping sets of target proteins, indicating that SUMO-1 and SUMO-2 may have both redundant and non-redundant cellular functions. Interestingly, 14 of the 25 SUMO-1-conjugated proteins contain zinc fingers. Although both SUMO family members play roles in many cellular processes, our data show that sumoylation is strongly associated with transcription because nearly one-third of the identified target proteins are putative transcriptional regulators.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Affinity
  • HeLa Cells
  • Humans
  • Multiprotein Complexes / isolation & purification*
  • Protein Binding
  • Protein Processing, Post-Translational
  • Proteomics / methods*
  • SUMO-1 Protein / metabolism*
  • Small Ubiquitin-Related Modifier Proteins / metabolism*
  • Transfection


  • Multiprotein Complexes
  • SUMO-1 Protein
  • SUMO2 protein, human
  • Small Ubiquitin-Related Modifier Proteins