Polymeric chains of SUMO-2 and SUMO-3 are conjugated to protein substrates by SAE1/SAE2 and Ubc9

J Biol Chem. 2001 Sep 21;276(38):35368-74. doi: 10.1074/jbc.M104214200. Epub 2001 Jul 12.


Conjugation of the small ubiquitin-like modifier SUMO-1/SMT3C/Sentrin-1 to proteins in vitro is dependent on a heterodimeric E1 (SAE1/SAE2) and an E2 (Ubc9). Although SUMO-2/SMT3A/Sentrin-3 and SUMO-3/SMT3B/Sentrin-2 share 50% sequence identity with SUMO-1, they are functionally distinct. Inspection of the SUMO-2 and SUMO-3 sequences indicates that they both contain the sequence psiKXE, which represents the consensus SUMO modification site. As a consequence SAE1/SAE2 and Ubc9 catalyze the formation of polymeric chains of SUMO-2 and SUMO-3 on protein substrates in vitro, and SUMO-2 chains are detected in vivo. The ability to form polymeric chains is not shared by SUMO-1, and although all SUMO species use the same conjugation machinery, modification by SUMO-1 and SUMO-2/-3 may have distinct functional consequences.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biopolymers
  • Cell Line
  • DNA Primers
  • Endonucleases
  • Fungal Proteins / metabolism*
  • Humans
  • Ligases / metabolism*
  • Lysine / metabolism
  • Molecular Sequence Data
  • Nuclear Cap-Binding Protein Complex*
  • Phosphoproteins*
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Small Ubiquitin-Related Modifier Proteins*
  • Substrate Specificity
  • Ubiquitin-Conjugating Enzymes*
  • Ubiquitins / chemistry
  • Ubiquitins / metabolism*


  • Biopolymers
  • CBC2 protein, S cerevisiae
  • DNA Primers
  • Fungal Proteins
  • Nuclear Cap-Binding Protein Complex
  • Phosphoproteins
  • SAE2 protein, S cerevisiae
  • SUMO2 protein, human
  • SUMO3 protein, human
  • Saccharomyces cerevisiae Proteins
  • Small Ubiquitin-Related Modifier Proteins
  • Ubiquitins
  • Ubiquitin-Conjugating Enzymes
  • Endonucleases
  • Ligases
  • ubiquitin-conjugating enzyme UBC9
  • Lysine