Stabilization of the MDM2 oncoprotein by interaction with the structurally related MDMX protein

J Biol Chem. 1999 Dec 31;274(53):38189-96. doi: 10.1074/jbc.274.53.38189.


The MDM2 oncoprotein has transforming potential that can be activated by overexpression, and it represents a critical regulator of the p53 tumor suppressor protein. To identify other factors with a potential role in influencing the expression and/or function of MDM2, we utilized a yeast two-hybrid screening protocol. Here we report that MDM2 physically interacts with a structurally related protein termed MDMX. The results obtained in these studies provide evidence that C-terminal RING finger domains, contained within both of these proteins, play an important role in mediating the association between MDM2 and MDMX. The interaction of these proteins interferes with MDM2 degradation, leading to an increase in the steady-state levels of MDM2. MDMX also inhibits MDM2-mediated p53 degradation, with subsequent accumulation of p53. Taken together, these data indicate that MDMX has the potential to regulate the expression and function of the MDM2 oncoprotein.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • DNA Primers
  • Humans
  • Nuclear Proteins*
  • Protein Binding
  • Protein Conformation
  • Proto-Oncogene Proteins / chemistry
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-mdm2
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / metabolism
  • Two-Hybrid System Techniques


  • DNA Primers
  • Nuclear Proteins
  • Proto-Oncogene Proteins
  • Tumor Suppressor Protein p53
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2