The PTEN, Mdm2, p53 tumor suppressor-oncoprotein network

Trends Biochem Sci. 2002 Sep;27(9):462-7. doi: 10.1016/s0968-0004(02)02166-7.


Oncoproteins and tumor-suppressor proteins regulate cell growth and viability. Recent observations show that phosphoinositide 3-kinase (PtdIns 3-kinase)-Akt signaling promotes the phosphorylation and movement of the Mdm2 oncoprotein into the nucleus, where it downregulates the p53 tumor-suppressor protein. The PTEN tumor suppressor protein inhibits activation of Akt and this restricts Mdm2 to the cytoplasm. Restriction of Mdm2 to the cytoplasm promotes p53 function and thereby sustains the sensitivity of cancer cells to chemotherapy. p53 acutely induces Mdm2, providing damaged cells the opportunity for repair, but subsequently induces PTEN, favoring the death of mutated or irrevocably damaged cells. Thus, oncoproteins and tumor suppressor proteins are networked to promote normal cell function and eliminate mutated cells.

Publication types

  • Review

MeSH terms

  • Animals
  • Humans
  • Nuclear Proteins*
  • PTEN Phosphohydrolase
  • Phosphoric Monoester Hydrolases / metabolism*
  • Protein-Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt
  • Proto-Oncogene Proteins c-mdm2
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / metabolism*
  • Tumor Suppressor Proteins / metabolism*


  • Nuclear Proteins
  • Proto-Oncogene Proteins
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • AKT1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Phosphoric Monoester Hydrolases
  • PTEN Phosphohydrolase
  • PTEN protein, human