Eukaryotic heat-shock protein

Li, G. Laszio, A. (1985). Thermotolerance in mammalian cells A possible role for the heat shock proteins. In Changes in Eukaryotic Gene Expression in Response to Environmental Stress (Atkinson, B.G. Walden, D.B. eds.), pp. 349-371, Academic Press, Orlando. 

Folding chaperons Prefolding as in eukaryotes Different heat shock proteins (chaperones)... 

Germot A, Philippe H, Le Guyader H (1996) Presence of a mitochondrial-type 70-kDa heat shock protein in Trichomonas vaginalis suggests a very early mitochondrial en-dosymbiosis in eukaryotes. Proc Natl Acad Sci USA 93 14614-14617... 

Many of the chaperones double as heat shock-proteins (Hsp). When a cell is put under stress that can cause proteins to denature, such as too high a temperature, it produces heat-shock proteins. Their names are abbreviated to Hsp plus their subunit molecular mass in kDa. Hsp70, for example, is a ubiquitous heat-shock protein in eukaryotes. It is known in E. coli as DnaK for historical reasons because it was first discovered from a supposed role in DNA replication. Hsp70 is also important in protein trafficking and the conveying of proteins across membranes, because the denatured state is important in these processes. In protein biosynthesis, the unfolded state of the nascent polypeptide chain is passed on to DnaK, which maintains it in an extended form. The chain, under the influence of ATP and co-chaperones such as DnaJ and GrpE, is handed over to GroEL. 

Liberek, K., Skowyra, D., Zylicz, M., Johnson, C., and Georgopoulos, C. (1991b). The Escherichia coli DnaK chaperone, the 70-kDa heat shock protein eukaryotic equivalent, changes conformation upon ATP hydrolysis, thus triggering its dissociation from a bound target protein, y. Biot. Chem. 266, 14491-14496. 

Another ATP-dependent protease identified among heat shock proteins of E. coli is known as HslV-HslU or (ClpQ-ClpY). It has a threonine protease active site and is even more closely remeniscient of eukaryotic proteasomes. Also active in E. coli is another ring-like protease, a membrane-bormd zinc endopeptidase FtsH (or HflB). " Similar eukaryotic proteases also exist. ... 

When exposed to heat shock or other types of stress, a large number of prokaryotic and eukaryotic cells synthesize a small family of proteins that have been termed heat shock proteins. These proteins complex with many other proteins, and a wide variety of physiological and molecular functions have... 

Some proteins, such as the antifreeze proteins in the bloodstream of Antarctic fish or the heat shock proteins found in eukaryotes, seem to defy classification. Many proteins perform more than one of these general functions, but typically, such proteins have only one primary function which is modulated, assisted, or regulated by one or more secondary functions. 

Originally described in analysis of plant gene expression, microarray was rapidly adopted for analysis of mammalian and lower eukaryotic transcriptosomes. Until very recently, analyses were restricted to small (approx 1000 gene) subsets or complete genomes of lower eukaryotes such as yeast. The original application in humans, used to demonstrate application of the technique, was an analysis of heat-shock proteins in T cells (4). 

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