10 The Mammalian Stress Response: Cell Physiology and Biochemistry of Stress Proteins

Abstract

I. INTRODUCTION
Organisms exhibit specific homeostatic-like responses when confronted with sudden changes in their environmental circumstance. As was discussed in some of the earlier chapters in this volume, the ability of an organism to adapt or acclimate to its new environment may be an integral driving force for evolution. At the cellular level, there are also a number of mechanisms by which the cell can respond and/or acclimate to changes in its normal growth environment. Examples of this include temporary or reversible changes in enzyme structure or function by which certain metabolic pathways are modified. Alternatively, there may be more long-term changes that involve permanent alterations in the pattern of gene expression, thereby facilitating the acclimation of the cell to its new environmental circumstance. Finally, all organisms appear to have developed a rather specific and remarkably similar strategy by which to confront abrupt changes in their surroundings, such as that which occurs following increases in their normal growth temperature. This latter response, historically referred to as the heat shock response, involves the coordinated increased expression of a group of proteins, the heat shock proteins (hsps), whose collective function appears to provide the cell protection during the insult and/or to facilitate the restoration of basic metabolic pathways that were perturbed as a consequence of the environmental insult (see also reviews by Ashburner and Bonner 1979; Nover 1984; Craig 1985; Lindquist 1986; Subjeck and Shyy 1986).

That the heat shock response is involved in the protection and/or enhanced survival of the cell...