Biology of the Heat Shock Response and Protein Chaperones: Budding Yeast (Saccharomyces cerevisiae) as a Model System

Abstract

SUMMARY The eukaryotic heat shock response is an ancient and highly conserved transcriptional program that results in the immediate synthesis of a battery of cytoprotective genes in the presence of thermal and other environmental stresses. Many of these genes encode molecular chaperones, powerful protein remodelers with the capacity to shield, fold, or unfold substrates in a context-dependent manner. The budding yeast Saccharomyces cerevisiae continues to be an invaluable model for driving the discovery of regulatory features of this fundamental stress response. In addition, budding yeast has been an outstanding model system to elucidate the cell biology of protein chaperones and their organization into functional networks. In this review, we evaluate our understanding of the multifaceted response to heat shock. In addition, the chaperone complement of the cytosol is compared to those of mitochondria and the endoplasmic reticulum, organelles with their own unique protein homeostasis milieus. Finally, we examine recent advances in the understanding of the roles of protein chaperones and the heat shock response in pathogenic fungi, which is being accelerated by the wealth of information gained for budding yeast.

Characterization and Identification of Differentially Expressed Genes Involved in Thermal Adaptation of the Hong Kong Oyster Crassostrea hongkongensis by Digital Gene Expression Profiling

“…Exposure to high temperature can trigger the synthesis of heat shock proteins (HSPs) and other molecular chaperones. Many HSPs function as molecular chaperones to protect thermally damaged proteins from aggregation, unfold aggregated proteins, and refold damaged proteins or target them for efficient degradation (Verghese et al, 2012). This explains the significant enrichment of the GO associated with protein folding and chaperone binding in the present study.…”

Yeast metabolic and signaling genes are required for heat-shock survival and have little overlap with the heat-induced genes

“…It should be recalled in this context that many other chaperone proteins have many paralogs and overlapping functions, so our experiment does not speak directly to the need for chaperones for heat-stress survival (14,36,37). Similarly, the realities that HSF1 is essential and that MSN2 and MSN4 have overlapping functions may well account for our failure to see significant increases in death rate for these deletions in our screen.…”

“…Classically, this set of genes/proteins includes the molecular chaperones, which often are induced in response to stress (14). However, by using the deletion collection to assay thermotolerance, we also can identify genes important for stress resistance that are either constitutively present or posttranslationally modified.…”

“…Both thermotolerance and acquired thermotolerance have been studied in detail, with a general focus on the roles of transcripts or proteins that increase in abundance as part of the heat-shock response (1,(11)(12)(13)(14). Classically, this set of genes/proteins includes the molecular chaperones, which often are induced in response to stress (14).…”

Proteasome Activity Is Influenced by the HECT_2 Protein Ipa1 in Budding Yeast

“…Nevertheless, the 498 usage of blue-light as switch has its advantages, as it does not influence expression of 499 yeast genes considerably ( Figure 5A and Supplemental Table S4). In contrast, a 500 temperature-shift induces the heat-shock response that alters the physiology of the cell 501 dramatically (Verghese et al 2012). 502…”