Biochemical characterisation of TCTP questions its function as a guanine nucleotide exchange factor for Rheb.
Translationally controlled tumour protein (TCTP) is involved in malignant transformation and regulation of apoptosis. It has been postulated to serve as a guanine nucleotide exchange factor for the small G-protein Rheb. Rheb functions in the PI3 kinase/mTOR pathway. The study presented here was initiated to characterise the interaction between TCTP and Rheb biochemically. Since (i) no exchange activity of TCTP towards Rheb could be detected in vitro, (ii) no interaction between TCTP and Rheb could be detected by NMR spectroscopy, and (iii) no effect of TCTP depletion in cells on the direct downstream targets of Rheb could be observed in vivo, this study shows that TCTP is unlikely to be a guanine nucleotide exchange factor for Rheb.
Rehmann
H
H
Department of Physiological Chemistry and Center for Biomedical Genetics, UMC Utrecht Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
Brüning
M
M
Berghaus
C
C
Schwarten
M
M
Köhler
K
K
Stocker
H
H
Stoll
R
R
Zwartkruis
F J
FJ
Wittinghofer
A
A
D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010766:Phosphorylation; D034622:RNA Interference; D000076205:Ras Homolog Enriched in Brain Protein; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D000090324:Tumor Protein, Translationally-Controlled 1; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D014408:Biomarkers, Tumor; D029721:Drosophila Proteins; D020662:Guanine Nucleotide Exchange Factors; D009479:Neuropeptides; C490211:RHEB protein, human; D000076205:Ras Homolog Enriched in Brain Protein; C000715647:TPT1 protein, human; D000090324:Tumor Protein, Translationally-Controlled 1; D019893:Ribosomal Protein S6 Kinases; D020559:Monomeric GTP-Binding Proteins; D020691:rab GTP-Binding Proteins