Enhanced SUMOylation of proteins containing a SUMO-interacting motif by SUMO-Ubc9 fusion

Eui Tae Kim, Kyeong Kyu Kim, Mike J. Matunis, Jin Hyun Ahn

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Identifying new targets for SUMO and understanding the function of protein SUMOylation are largely limited by low level of SUMOylation. It was found recently that Ubc9, the SUMO E2 conjugating enzyme, is covalently modified by SUMO at a lysine 14 in the N-terminal alpha helix, and that SUMO-modified Ubc9 has enhanced conjugation activity for certain target proteins containing a SUMO-interacting motif (SIM). Here, we show that, compared to intact Ubc9, the SUMO-Ubc9 fusion protein has higher conjugating activity for SIM-containing targets such as Sp100 and human cytomegalovirus IE2. Assays using an IE2 SIM mutant revealed the requirement of SIM for the enhanced IE2 SUMOylation by SUMO-Ubc9. In pull-down assays with cell extracts, the SUMO-Ubc9 fusion protein bound to more diverse cellular proteins and interacted with some SIM-containing proteins with higher affinities than Ubc9. Therefore, the devised SUMO-Ubc9 fusion will be useful for identifying SIM-containing SUMO targets and producing SUMO-modified proteins.

Original languageEnglish (US)
Pages (from-to)41-45
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Oct 9 2009


  • HCMV
  • IE2
  • SIM
  • SUMO
  • SUMO-interacting motif
  • Sp100
  • Ubc9

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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