scholarly journals Cell-specific expression of heat shock proteins in chicken reticulocytes and lymphocytes.

1984 ◽  
Vol 99 (4) ◽  
pp. 1316-1323 ◽  
Author(s):  
R Morimoto ◽  
E Fodor
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Gel Electrophoresis ◽  
Elevated Temperatures ◽  
Major Protein ◽  
Beta Globin ◽  
Specific Expression ◽  
Two Dimensional Gel Electrophoresis ◽  
Globin Synthesis ◽  
Shock Proteins

We have found that chicken reticulocytes respond to elevated temperatures by the induction of only one heat shock protein, HSP70, whereas lymphocytes induce the synthesis of all four heat shock proteins (89,000 mol wt, HSP89; 70,000 mol wt, HSP70; 23,000 mol wt, HSP23; and 22,000 mol wt, HSP22). The synthesis of HSP70 in lymphocytes was rapidly induced by small increases in temperature (2 degrees-3 degrees C) and blocked by preincubation with actinomycin D. Proteins normally translated at control temperatures in reticulocytes or lymphocytes were not efficiently translated after incubation at elevated temperatures. The preferential translation of mRNAs that encode the heat shock proteins paralleled a block in the translation of other cellular proteins. This effect was most prominently observed in reticulocytes where heat shock almost completely repressed alpha- and beta-globin synthesis. HSP70 is one of the major nonglobin proteins in chicken reticulocytes, present in the non-heat-shocked cell at approximately 3 X 10(6) molecules per cell. We compared HSP70 from normal and heat-shocked reticulocytes by two-dimensional gel electrophoresis and by digestion with Staphylococcus aureus V8 protease and found no detectable differences to suggest that the P70 in the normal cell is different from the heat shock-induced protein, HSP70. P70 separated by isoelectric focusing gel electrophoresis into two major protein spots, an acidic P70A (apparent pl = 5.95) and a basic P70B (apparent pl = 6.2). We observed a tissue-specific expression of P70A and P70B in lymphocytes and reticulocytes. In lymphocytes, P70A is the major 70,000-mol-wt protein synthesized at normal temperatures whereas only P70B is synthesized at normal temperatures in reticulocytes. Following incubation at elevated temperatures, the synthesis of both HSP70A and HSP70B was rapidly induced in lymphocytes, but synthesis of only HSP70B was induced in reticulocytes.

scholarly journals Multiple Small Heat Shock Proteins in Rhizobia

1999 ◽  
Vol 181 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Martin Münchbach ◽  
Andreas Nocker ◽  
Franz Narberhaus
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Gel Electrophoresis ◽  
Immunoblot Analysis ◽  
Small Heat Shock Proteins ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Significant Similarity ◽  
Class A ◽  
Shock Proteins

ABSTRACT Seven genes coding for small heat shock proteins (sHsps) inBradyrhizobium japonicum have been identified. They are organized in five operons that are coordinately regulated by ROSE, a negatively cis-acting DNA element. The deduced sHsps can be divided into two separate classes: class A, consisting of proteins that show similarity to Escherichia coli IbpA and IbpB, and class B, whose members display significant similarity to other sHsps from prokaryotes and eukaryotes. Two-dimensional gel electrophoresis and Edman sequencing revealed the presence of at least 12 sHsps inB. japonicum, indicating a remarkable abundance of sHsps in this organism. Three additional members of class A and two potentially novel heat shock proteins were identified on the basis of their amino termini. The presence of multiple sHsps was also demonstrated for a variety of Rhizobium and Bradyrhizobium species by immunoblot analysis and two-dimensional gel electrophoresis. An extensive database survey revealed that, in contrast to the rhizobia, other bacteria contain maximally two sHsps whereas many plants have been reported to possess a sHsp superfamily.

Heat shock proteins functioning as molecular chaperones: their roles in normal and stressed cells

1993 ◽  
Vol 339 (1289) ◽  
pp. 327-333 ◽  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Molecular Chaperones ◽  
Stress Proteins ◽  
Elevated Temperatures ◽  
Metabolic Stress ◽  
Hsp 70 ◽  
Degree Of Protection ◽  
Stressed Cells ◽  
Shock Proteins

In response to either elevated temperatures or several other metabolic insults, cells from all organisms respond by increasing the expression of so-called heat shock proteins (hsp or stress proteins). In general, the stress response appears to represent a universal cellular defence mechanism. The increased expression and accumulation of the stress proteins provides the cell with an added degree of protection. Studies over the past few years have revealed a role for some of the stress proteins as being intimately involved in protein maturation. Members of the hsp 70 family, distributed throughout various intracellular compartments, interact transiently with other proteins undergoing synthesis, translocation, or higher ordered assembly. Although not yet proven, it has been suggested that members of the hsp 70 family function to slow down or retard the premature folding of proteins in the course of synthesis and translocation. Yet another family of stress proteins, the hsp 60 or GroEL proteins (chaperonins), appear to function as catalysts of protein folding. Here I discuss the role of those stress proteins functioning as molecular chaperones, both within the normal cell and in the cell subjected to metabolic stress.

The role of heat-shock proteins in thermotolerance

1993 ◽  
Vol 339 (1289) ◽  
pp. 279-286 ◽  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
High Temperatures ◽  
Fruit Fly ◽  
Yeast Cells ◽  
Major Protein ◽  
Wild Type ◽  
Hsp 70 ◽  
Shock Proteins

The role of heat-shock proteins (hsps) in thermotolerance was examined in the budding yeast Saccharomyces cerevisiae and in the fruit fly Drosophila melanogaster . In yeast cells, the major protein responsible for thermotolerance is hsp 100. In cells carrying mutations in the hsp 100 gene, HSP 104 , growth is normal at both high and low temperatures, but the ability of cells to survive extreme temperatures is severely impaired. The loss of thermotolerance is apparently due to the absence of the hsp 104 protein itself because, with the exception of the hsp 104 protein, no differences in protein profiles were observed between mutant and wild-type cells. Aggregates found in mutant cells at high temperatures suggest that the cause of death may be the accumulation of denatured proteins. No differences in the rates of protein degradation were observed between mutant and wild-type cells. This, and genetic analysis of cells carrying multiple hsp 70 and hsp 104 mutations, suggests that the primary function of hsp 104 is to rescue proteins from denaturation rather than to degrade them once they have been denatured. Drosophila cells do not produce a protein in the hsp 100 class in response to high temperatures. In this organism, hsp 70 appears to be the primary protein involved in thermotolerance. Thus, the relative importance of different hsps in thermotolerance changes from organism to organism.

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