Heat shock-induced translational alterations in HeLa cells. Initiation factor modifications and the inhibition of translation.

Abstract

Heat shock at 45 degrees C virtually abolishes protein synthesis in HeLa cells, but return to 37 degrees C effects a complete recovery and the concomitant synthesis of heat shock-induced proteins. Heat shock induces polysome disaggregation, indicating initiation is principally inhibited. In vitro assays for initiation factor activities reveal heat shock inhibits eukaryotic initiation factor 2 (eIF-2), eIF-(3 + 4F), and eIF-4B. Immunoblot analyses show that eIF-2 alpha and eIF-2 beta become modified during heat shock, and eIF-4B variants disappear. Upon return to 37 degrees C, these alterations reverse. The modifications of eIF-2 alpha and eIF-4B are due to phosphorylation and dephosphorylation, respectively. Enzymatic activities induced by heat shock inhibit protein synthesis and modify initiation factors in a rabbit reticulocyte lysate. Initiation factor modifications may contribute to, or cause, protein synthesis inhibition.

• Authors: R Duncan, J W Hershey
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 259 Issue 19 Pg. 11882-9 (Oct 10 1984) ISSN: 0021-9258 [Print] United States
• PMID: 6384217 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Heat-Shock Proteins
• Peptide Initiation Factors

Topics

• Centrifugation, Density Gradient
• Electrophoresis, Polyacrylamide Gel
• HeLa Cells (analysis)
• Heat-Shock Proteins (biosynthesis)
• Hot Temperature
• Humans
• Immunosorbent Techniques
• Peptide Initiation Factors (biosynthesis)
• Protein Biosynthesis