INHIBITION OF GLUCOSE-REGULATED AND HEAT-SHOCK PROTEIN INDUCTION BY LOW-TEMPERATURE

The present study evaluating induction of the major stress proteins in the subphysiological temperature range (25-33° C) shows that none of the agents used could effectively induce the heat shock proteins (hsp) or the glucose related protein grp95 at low temperature. However, grp82 was still induced by some amino acide analogs and by glucose deprivation while certain oxygen-regulated proteins were still induced by hypoxia at 25° C. Analogs were incorporated and protein turnover was increased at low temperature even though most stress proteins were not induced. Synthesis of hsps, but not that of grps, was induced if cultures containing analog-substituted proteins were shifted to 37° C. Temperature dependence of hsp induction by arsenite showed a sharp threshold between 30° C and 33° C. Low temperature inhibition of induction points to the existence of a temperature-dependent mechanism operating within the normal physiological temperature range and may be a useful parameter in evaluating proposed mechanisms of stress protein regulation. © 1990.