MDM2 interacts with MDMX through their RING finger domains

FEBS Lett. 1999 Mar 19;447(1):5-9. doi: 10.1016/s0014-5793(99)00254-9.


The N-terminus of MDM2 proto-oncoprotein interacts with p53 and down modulates p53 activity by inhibiting transcriptional activity and promoting p53 degradation. MDMX is structurally related to MDM2 and also binds to p53. However, the function of MDMX has not been clarified yet. We found that MDM2 hetero-oligomerized with MDMX through their C-terminal RING finger domains. Yeast two-hybrid analysis revealed that the hetero-oligomerization between MDMX and MDM2 was more stable than the homo-oligomerization of each protein. MDM2 has been shown to be degraded by the ubiquitin-proteasome pathway, while MDMX was a stable protein. Interaction of MDMX with MDM2 through the C-terminal RING finger domains resulted in inhibiting degradation of MDM2. These data indicate that MDMX functions as a regulator of MDM2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cloning, Molecular
  • Nuclear Proteins*
  • Protein Binding
  • Protein Conformation
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-mdm2
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Tumor Suppressor Protein p53 / metabolism
  • Zinc Fingers*


  • Nuclear Proteins
  • Proto-Oncogene Proteins
  • Recombinant Proteins
  • Tumor Suppressor Protein p53
  • Proto-Oncogene Proteins c-mdm2