Phosphorylation of Elongation Factor 1 and Ribosomal Protein S6 by Multipotential S6 Kinase and Insulin Stimulation of Translational Elongation

Authors

Y W Chang
J A Traugh

Publication Date

11-7-1997

Journal

EBioMedicine

DOI

10.1016/j.ebiom.2024.105377

PMID

39353277

PMCID

PMC11472629

PubMedCentral® Posted Date

9-30-2024

PubMedCentral® Full Text Version

Post-print

Abstract

Stimulation of protein synthesis in response to insulin is concomitant with increased phosphorylation of initiation factors 4B and 4G and ribosomal protein S6 (Morley, S. J., and Traugh, J. A. (1993) Biochimie 75, 985-989) and is due at least in part to multipotential S6 kinase. When elongation factor 1 (EF-1) from rabbit reticulocytes was examined as substrate for multipotential S6 kinase, up to 1 mol/mol of phosphate was incorporated into the alpha, beta, and delta subunits. Phosphorylation of EF-1 resulted in a 2-2. 6-fold stimulation of EF-1 activity, as measured by poly(U)-directed polyphenylalanine synthesis. The rate of elongation was also stimulated by approximately 2-fold with 80 S ribosomes phosphorylated on S6 by multipotential S6 kinase. When the rates of elongation in extracts from serum-fed 3T3-L1 cells and cells serum-deprived for 1.5 h were compared, a 40% decrease was observed upon serum deprivation. The addition of insulin to serum-deprived cells for 15 min stimulated elongation to a rate equivalent to that of serum-fed cells. Similar results were obtained with partially purified EF-1, with both EF-1 and ribosomes contributing to stimulation of elongation. These data are consistent with a ribosomal transit time of 3.2 min for serum-deprived cells and 1.6 min following the addition of insulin for 15 min. Taken together, the data suggest that insulin stimulation involves coordinate regulation of EF-1 and ribosomes through phosphorylation by multipotential S6 kinase.

Keywords

3T3 Cells, Animals, Insulin, Mice, Peptide Chain Elongation, Translational, Peptide Elongation Factor 1, Peptide Elongation Factors, Peptide Mapping, Phosphorylation, Rabbits, Ribosomal Protein S6, Ribosomal Protein S6 Kinases, Ribosomal Proteins, Biomarker, Longitudinal analysis, Lung cancer screening, Lung cancer risk assessment

Published Open-Access

yes

Recommended Citation

Y W Chang and J A Traugh, "Phosphorylation of Elongation Factor 1 and Ribosomal Protein S6 by Multipotential S6 Kinase and Insulin Stimulation of Translational Elongation" (1997). Faculty, Staff and Student Publications. 3014.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/3014