The relationship of heat-shock proteins, thermotolerance, and protein synthesis.
The relationship of heat-induced inhibition of protein synthesis (HIIPS) and thermotolerance, the transient ability to survive otherwise lethal heat treatments, was studied in HA-1 Chinese hamster fibroblasts exposed to various treatments. A mild heatshock or exposure to sodium arsenite induced a refractoriness to HIIPS, while exposure to the amino acid analog of proline, azetidine, did not. The development and decay of refractoriness to HIIPS after exposure to heat or sodium arsenite paralleled in the increase and decrease of the rate of synthesis of the heat-shock proteins (HSP), and was associated with neither the persistence of elevated levels of HSP nor the persistence of the thermotolerant state. Refractoriness to HIIPS was not associated with the elevated synthesis of HSP in the presence of amino acid analogs regardless of the mode of induction, indicating a requirement for functional HSP for the effect. The refractoriness to HIIPS was also found in heat-resistant variants of HA-1 cells that express elevated levels of hsp 70, implicating a role for this protein in this process. Our observation establish an unique biological effect associated with the period of elevated synthesis of the HSP, especially the hsp 70.
Laszlo
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Department of Radiology, Washington University Medical Center, St. Louis, Missouri 63108.
D000818:Animals; D001151:Arsenic / Q000494:pharmacology; D018053:Arsenites; D002460:Cell Line; D002470:Cell Survival; D003720:Densitometry; D004586:Electrophoresis; D005347:Fibroblasts; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature; D014176:Protein Biosynthesis; D012588:Scintillation Counting; D017670:Sodium Compounds; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D018053:Arsenites; D006360:Heat-Shock Proteins; D017670:Sodium Compounds; D013439:Sulfhydryl Reagents; C017947:sodium arsenite; D001151:Arsenic