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.