Translationally controlled tumor protein acts as a guanine nucleotide dissociation inhibitor on the translation elongation factor eEF1A

Proc Natl Acad Sci U S A. 2003 Nov 25;100(24):13892-7. doi: 10.1073/pnas.2335950100. Epub 2003 Nov 17.

Abstract

Recently, we demonstrated that the expression levels of the translationally controlled tumor protein (TCTP) were strongly down-regulated at the mRNA and protein levels during tumor reversion/suppression and by the activation of p53 and Siah-1. To better characterize the function of TCTP, a yeast two-hybrid hunt was performed. Subsequent analysis identified the translation elongation factor, eEF1A, and its guanine nucleotide exchange factor, eEF1Bbeta, as TCTP-interacting partners. In vitro and in vivo studies confirmed that TCTP bound specifically eEF1Bbeta and eEF1A. Additionally, MS analysis also identified eEF1A as a TCTP interactor. Because eEF1A is a GTPase, we investigated the role of TCTP on the nucleotide exchange reaction of eEF1A. Our results show that TCTP preferentially stabilized the GDP form of eEF1A, and, furthermore, impaired the GDP exchange reaction promoted by eEF1Bbeta. These data suggest that TCTP has guanine nucleotide dissociation inhibitor activity, and, moreover, implicate TCTP in the elongation step of protein synthesis.

MeSH terms

  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism*
  • Drug Stability
  • Guanine Nucleotide Dissociation Inhibitors / genetics
  • Guanine Nucleotide Dissociation Inhibitors / metabolism*
  • Guanine Nucleotides / metabolism*
  • Guanosine Diphosphate / metabolism
  • Humans
  • In Vitro Techniques
  • Kinetics
  • Peptide Elongation Factor 1 / genetics
  • Peptide Elongation Factor 1 / metabolism*
  • Protein Biosynthesis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Tumor Protein, Translationally-Controlled 1
  • Two-Hybrid System Techniques

Substances

  • Biomarkers, Tumor
  • Guanine Nucleotide Dissociation Inhibitors
  • Guanine Nucleotides
  • Peptide Elongation Factor 1
  • Recombinant Fusion Proteins
  • TPT1 protein, human
  • Tumor Protein, Translationally-Controlled 1
  • Guanosine Diphosphate