CHIP chaperones wild type p53 tumor suppressor protein

J Biol Chem. 2007 Sep 28;282(39):28441-28454. doi: 10.1074/jbc.M703698200. Epub 2007 Jul 31.

Abstract

Wild type p53 exists in a constant state of equilibrium between wild type and mutant conformation and undergoes conformational changes at elevated temperature. We have demonstrated that the co-chaperone CHIP (carboxyl terminus of Hsp70-interacting protein), which suppressed aggregation of several misfolded substrates and induced the proteasomal degradation of both wild type and mutant p53, physically interacts with the amino terminus of WT53 and prevented it from irreversible thermal inactivation. CHIP preferentially binds to the p53 mutant phenotype and restored the DNA binding activity of heat-denatured p53 in an ATP-independent manner. In cells under elevated temperatures that contained a higher level of p53 mutant phenotype, CHIP restored the native-like conformation of p53 in the presence of geldanamycin, whereas CHIP-small interfering RNA considerably increased the mutant form. Further, under elevated temperatures, the levels of CHIP and p53 were higher in nucleus, and chromatin immunoprecipitation shows the presence of p53 and CHIP together upon the DNA binding site in the p21 and p53 promoters. We propose that CHIP might be a direct chaperone of wild type p53 that helps p53 in maintaining wild type conformation under physiological condition as well as help resurrect p53 mutant phenotype into a folded native state under stress condition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Benzoquinones / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Heat-Shock Response / drug effects
  • Heat-Shock Response / physiology*
  • Hot Temperature
  • Humans
  • KB Cells
  • Lactams, Macrocyclic / pharmacology
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Mutation
  • Proteasome Endopeptidase Complex / metabolism
  • Protein Binding / drug effects
  • Protein Binding / physiology
  • Protein Denaturation / drug effects
  • Protein Folding*
  • Protein Structure, Tertiary / genetics
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology
  • Response Elements / drug effects
  • Response Elements / physiology
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Ubiquitin-Protein Ligases / antagonists & inhibitors
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*

Substances

  • Benzoquinones
  • Enzyme Inhibitors
  • Lactams, Macrocyclic
  • Molecular Chaperones
  • RNA, Small Interfering
  • Tumor Suppressor Protein p53
  • Adenosine Triphosphate
  • STUB1 protein, human
  • Ubiquitin-Protein Ligases
  • Proteasome Endopeptidase Complex
  • geldanamycin