ABSTRACT
Eukaryotic cells respond to chemical or physical stress by global alterations in protein synthesis, characterized by a cessation of constitutive cellular protein synthesis, coupled with a transient overexpression of distinct protein families, termed stress proteins. Expression of the glucose-regulated proteins, a distinct family of stress proteins, is observed in mammalian cells as a response to glucose starvation, anoxia, intracellular calcium flux, oxidative stress, sulfhydryl reagents, and agents that interfere with protein glycosylation. Expression of HSP following thermal stress is correlated with the development of transient cellular resistance to a subsequent heat shock. The HSPs may sequester thermally denatured protein in the cytosol, mitochondria, and nucleus. Preliminary studies have suggested a role for glucose-regulated families-78 expression in the development of cellular resistance to oxidative stress. Eukaryotic gene promoters contain ds-acting sequence motifs in their 5' regulatory regions that serve as binding sites for trans-acting protein factors responsible for constitutive or inducible gene expression.
