SciCrunch will be offline today beginning at 6:30 PM PDT for about 15 minutes.
  • Register
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.


Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.


SUMO-1 modification of IkappaBalpha inhibits NF-kappaB activation.

Activation of NF-kappaB is achieved by ubiquitination and proteasome-mediated degradation of IkappaBalpha. We have detected modified IkappaBalpha, conjugated to the small ubiquitin-like protein SUMO-1, which is resistant to signal-induced degradation. In the presence of an E1 SUMO-1-activating enzyme, Ubch9 conjugated SUMO-1 to IkappaBalpha primarily on K21, which is also utilized for ubiquitin modification. Thus, SUMO-1-modified IkappaBalpha cannot be ubiquitinated and is resistant to proteasome-mediated degradation. As a result, overexpression of SUMO-1 inhibits signal-induced activation of NF-kappaB-dependent transcription. Unlike ubiquitin modification, which requires phosphorylation of S32 and S36, SUMO-1 modification of IkappaBalpha is inhibited by phosphorylation. Thus, while ubiquitination targets proteins for rapid degradation, SUMO-1 modification acts antagonistically to generate proteins resistant to degradation.

Pubmed ID: 9734360


  • Desterro JM
  • Rodriguez MS
  • Hay RT


Molecular cell

Publication Data

August 18, 1998

Associated Grants


Mesh Terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Line
  • Cysteine Endopeptidases
  • DNA, Recombinant
  • DNA-Binding Proteins
  • Humans
  • I-kappa B Proteins
  • Interleukin-1
  • Macromolecular Substances
  • Multienzyme Complexes
  • NF-kappa B
  • Proteasome Endopeptidase Complex
  • Recombinant Proteins
  • SUMO-1 Protein
  • Signal Transduction
  • Transcriptional Activation
  • Tumor Necrosis Factor-alpha
  • Ubiquitins