Modulation of heat shock polypeptide synthesis in HeLa cells during hyperthermia and recovery

In HeLa cells incubated at 42 degree C, the rate of protein synthesis undergoes a rapid reduction, followed by a gradual increase over the next few hours. In the present study, the authors show that the recovery of protein synthesis during hyperthermia corresponds to the increased synthesis of three size classes of heat-shock polypeptides (M sub(r) 27,000, 70,000, and 80,000). The modulation of heat-shock protein synthesis during hyperthermia and recovery involves the accumulation and subsequent inactivation of highly efficient mRNAs. The heat-shock mRNAs are translated preferentially under the conditions of reduced polypeptide chain initiation that occur at elevated temperatures.