Correlation between synthesis of heat shock proteins and development of thermotolerance in Chinese hamster fibroblasts.

TLDR

Heat shock proteins are induced by environmental stresses and are thought to be essential for cell survival. The study examined how brief heat treatments (41–46 °C) affect heat‑shock protein synthesis and survival in plateau‑phase Chinese hamster fibroblast HA‑1 cells. Heat‑shock protein synthesis was markedly increased after both 41 °C and 46 °C treatments, correlating with a 10²–10⁶‑fold rise in survival after lethal heat challenge; the persistence of thermotolerance up to 36 h matched the stability of proteins with Mr 70,000 or 87,000, and other stressors such as sodium arsenite, hypoxia, and ethanol also induced heat‑shock proteins and transient thermotolerance.

Abstract

Synthesis of a family of proteins called "heat shock" proteins is induced or enhanced in cells in response to various environmental stresses, suggesting that these proteins may perform functions essential to cell survival. Because a brief, nonlethal heat treatment can dramatically induce a transient resistance to a subsequent lethal heat treatment (thermotolerance), we examined the effect of heat treatment (41-46 degrees C) on protein synthesis and cell survival in plateau-phase Chinese hamster fibroblast (HA-1) cells. After heat treatments that either drastically inhibited total protein synthesis (46 degrees C) or did not suppress it (41 degrees C), the synthesis of heat shock proteins was greatly enhanced over that in unheated cells, and cell survival was increased 10(2)- to 10(6)-fold when cells were challenged by a subsequent lethal heat treatment. The synthesis of heat shock proteins correlated well with the development of thermotolerance, and the stability of these proteins correlated well with the persistence of thermotolerance up to 36 hr. Sodium arsenite, hypoxia, and ethanol also induced both the synthesis of heat shock proteins and transient thermotolerance. A qualitative analysis of individual proteins suggests that the synthesis and persistence of polypeptides of Mr 70,000 or 87,000 most closely conformed to the kinetics of thermotolerance.