Mel-18 interacts with RanGAP1 and inhibits its sumoylation

Jie Zhang, Kevin D. Sarge

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Our previous results showed that the polycomb protein mel-18 binds to a protein called HSF2 and inhibits HSF2 sumoylation, thereby functioning as an anti-SUMO E3 factor. This study also suggested that mel-18 regulates the sumoylation of other cellular proteins, but the identities of these other proteins were unknown. Here we show that mel-18 interacts with the RanGAP1 protein and inhibits its sumoylation, and that these activities do not require the RING domain of mel-18. The results also show that RanGAP1 sumoylation is decreased during mitosis, and that this is associated with increased interaction between RanGAP1 and mel-18 during this stage of the cell cycle. Intriguingly, this regulatory relationship is the opposite of that found for mel-18 and HSF2, in which the interaction between these two proteins decreases during mitosis, resulting in elevated HSF2 sumoylation. The results of this study strengthen the conclusion that mel-18 functions as an anti-SUMO E3 factor, and extend its targets to include regulation of the sumoylation of the important cellular protein RanGAP1.

Original languageEnglish
Pages (from-to)252-255
Number of pages4
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - Oct 17 2008

Bibliographical note

Funding Information:
We thank Mike Matunis for the RanGAP1 construct, and other members of the laboratory for insightful discussions. This research was supported by NIH Grant GM64606 to K.D.S.


  • Mel-18
  • Mitosis
  • Polycomb
  • RanGAP1
  • SUMO
  • SUMO-1

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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