Differential induction of glucose‐regulated and heat shock proteins: Effects of pH and sulfhydryl‐reducing agents on chicken embryo cells

Abstract

Glucose‐regulated and heat shock proteins are two subsets of eukaryotic stress proteins that can be induced differentially, simultaneously, and reciprocally. Two new inducers, low extracellular pH and 2‐mercaptoethanol, that stimulate chicken embryo cells to synthesize glucose‐regulated proteins rapidly were found. Two classes of cellular targets for mercaptoethanol were defined operationally, one dependent on and the other independent of protein synthesis. A new inducer of heat shock proteins, high extracellular pH, was found as well. Inductions by low and high extracellular pH were inhibited by actinomycin D but were insensitive to cycloheximide. Inductions of glucose‐regulated and heat shock proteins are discussed in terms of changes in intracellular pH and sulfhydryl oxidation states.