scholarly journals Conservative innovation: The mixed-up evolutionary history of the heat-shock proteins

2014 ◽  
Vol 36 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Elizabeth R. Waters

In this review, I briefly describe the distinct evolutionary history of each of the major heat-shock protein families (HSPs). If you view the cell as a complex and optimized machine and study only the heat-shock response and chaperone network in a single species, such as humans, yeast or Arabidopsis, you would find a complex molecular machinery with many ‘parts’ or proteins that work in a co-ordinate fashion to disaggregate and fold proteins. The close association and importance of these proteins parts would lead you to believe that this cellular machine could not work if some parts were missing, had been differentially manufactured or were present in differing amounts. Yet, this is just what we find when we look at the evolution of the HSPs. What makes the evolution of the HSPs and the chaperone network so fascinating is that, on the one hand, the HSPs are highly conserved, work in a collaborative fashion and are necessary for life. On the other hand, each domain of life (Archaea, Bacteria and Eukarya) has a different subset of HSPs, and each HSP family has a unique evolutionary history.

Author(s):  
Edgardo Moreno

ABSTRACT The genus Brucella, described by Meyer and Shaw in 1920, comprises bacterial pathogens of veterinary and public health relevance. For 36 years, the genus came to include three species that caused brucellosis in livestock and humans. In the second half of the 20th century, bacteriologists discovered five new species and several ʻatypicalʼ strains in domestic animals and wildlife. In 1990, the Brucella species were recognized as part of the Class Alphaproteobacteria, clustering with pathogens and endosymbionts of animals and plants such as Bartonella, Agrobacterium and Ochrobactrum; all bacteria that live in close association with eukaryotic cells. Comparisons with Alphaproteobacteria contributed to identify virulence factors and to establish evolutionary relationships. Brucella members have two circular chromosomes, are devoid of plasmids, and display close genetic relatedness. A proposal, asserting that all brucellae belong to a single species with several subspecies debated for over 70 years, was ultimately rejected in 2006 by the subcommittee of taxonomy, based on scientific, practical, and biosafety considerations. Following this, the nomenclature of having multiples Brucella species prevailed and defined according to their molecular characteristics, host preference, and virulence. The 100-year history of the genus corresponds to the chronicle of scientific efforts and the struggle for understanding brucellosis.


1988 ◽  
Vol 34 (2) ◽  
pp. 162-168 ◽  
Author(s):  
H. S. Roychowdhury ◽  
M. Kapoor

In Neurospora crassa, heat shock results in the induction of 9 to 11 heat shock proteins (HSP), of which HSP80 is the most abundant and the first to be synthesized. The induction of HSP80 was investigated during normal growth (2% sucrose) and under sucrose starvation. Transfer of mycelium to a medium supplemented with ethanol stimulated the synthesis of HSP80, even at the normal growth temperature of 28 °C. It was also synthesized under carbon starvation conditions, where the medium was supplemented with 0.02% sucrose, 0.3% acetate, 0.2% lactate, or ethanol. A 30–35 kilodalton polypeptide was induced by heat shock in carbon-sufficient media, but in 0.02% sucrose and 0.3% acetate containing media it was synthesized at normal temperatures. While the overall heat shock response remained unaltered in these cultures, the abundance of HSP90 and HSP70, relative to HSP80, was greater. HSP80 appears to be controlled by carbon-catabolite repression as well as heat shock. Another high molecular mass protein (tentatively designated alc'80') was observed to be induced by heat shock, provided carbon starvation conditions prevailed concurrently.


2001 ◽  
Vol 280 (3) ◽  
pp. C614-C620 ◽  
Author(s):  
Chantal Colmont ◽  
Stéphanie Michelet ◽  
Dominique Guivarc'h ◽  
Germain Rousselet

Urea, with NaCl, constitutes the osmotic gradient that allows water reabsorption in mammalian kidneys. Because NaCl induces heat shock proteins, we tested the responses to heat shock of mIMCD3 cells adapted to permissive urea and/or NaCl concentrations. We found that heat-induced cell death was stronger after adaptation to 250 mM urea. This effect was reversible, dose dependent, and, interestingly, blunted by 125 mM NaCl. Moreover, we have shown that urea-adapted cells engaged in an apoptotic pathway upon heat shock, as shown by DNA laddering. This sensitization is not linked to a defect in the heat shock response, because the induction of HSP70 was similar in isotonic and urea-adapted cells. Moreover, it is not linked to the presence of urea inside cells, because washing urea away did not restore heat resistance and because applying urea and heat shock at the same time did not lead to heat sensitivity. Together, these results suggest that urea modifies the heat shock response, leading to facilitated apoptosis.


1987 ◽  
Vol 7 (1) ◽  
pp. 244-250
Author(s):  
D Y Shin ◽  
K Matsumoto ◽  
H Iida ◽  
I Uno ◽  
T Ishikawa

When Saccharomyces cerevisiae cells grown at 23 degrees C were transferred to 36 degrees C, they initiated synthesis of heat shock proteins, acquired thermotolerance to a lethal heat treatment given after the temperature shift, and arrested their growth transiently at the G1 phase of the cell division cycle. The bcy1 mutant which resulted in production of cyclic AMP (cAMP)-independent protein kinase did not synthesize the three heat shock proteins hsp72A, hsp72B, and hsp41 after the temperature shift. The bcy1 cells failed to acquire thermotolerance to the lethal heat treatment and were not arrested at the G1 phase after the temperature shift. In contrast, the cyr1-2 mutant, which produced a low level of cAMP, constitutively produced three heat shock proteins and four other proteins without the temperature shift and was resistant to the lethal heat treatment. The results suggest that a decrease in the level of cAMP-dependent protein phosphorylation results in the heat shock response, including elevated synthesis of three heat shock proteins, acquisition of thermotolerance, and transient arrest of the cell cycle.


2021 ◽  
Author(s):  
Zhiying Miao ◽  
Weikang Yu ◽  
Yueyang Wang ◽  
Xianhong Gu ◽  
Xiaohua Teng

Abstract Background: Lead (Pb) is a toxic environmental pollutant and can exerts toxicity in kidneys. It is known that selenium (Se) has an antagonistic effect on Pb poisoning. However, biological events during the process were not well understood in chicken kidneys.Methods: One hundred and eighty male Hyline chickens (7-day-old) were randomly divided into the control group (offering standard diet and potable water), the Se group (offering Na2SeO3-added standard diet and potable water), the Pb group (offering standard diet and (CH3OO)2Pb-added potable water), and the Pb+Se group (offering Na2SeO3-added standard diet and (CH3OO)2Pb-added potable water). On 30th, 60th, and 90th days, kidneys were removed to perform the studies of histological structure, oxidative stress indicators, cytokines, heat shock proteins, and autophagy in the chicken kidneys.Results: The experimental results indicated that Pb poisoning changed renal histological structure; decreased catalase, glutathione-s-transferase, and total antioxidative capacity activities; increased hydrogen peroxide content; induced mRNA and protein expression of heat shock proteins; inhibited interleukin (IL)-2 mRNA expression, and induced IL-4 and IL-12β mRNA expression; inhibited mammalian target of rapamycin mRNA and protein expression, and induced autophagy-related gene mRNA and protein expression in the chicken kidneys. Supplement of Se mitigated the above changes caused by Pb.Conclusion: Our research strengthens the evidence that Pb induced oxidative stress, inflammation, heat shock response, and autophagy and Se administration alleviated Pb poisoning through mitigating oxidative stress in the chicken kidneys.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Xin Zhang ◽  
Yuting Li ◽  
Yulong Sun ◽  
Mingxing Guo ◽  
Jianjun Feng ◽  
...  

Abstract Background The effects of diverse stresses ultimately alter the structures and functions of proteins. As molecular chaperones, heat shock proteins (HSPs) are a group of highly conserved proteins that help in the refolding of misfolded proteins and the elimination of irreversibly damaged proteins. They are mediated by a family of transcription factors called heat shock factors (HSFs). The small abalone Haliotis diversicolor is a species naturally distributed along the southern coast of China. In this study, the expression of HdHSF1 was inhibited by RNAi in hemocytes in order to further elucidate the regulatory roles of HdHSF1 on heat shock responsive genes in abalone. Meanwhile, to understand the transcriptional regulation of the HdHSF1 gene, the 5′-upstream regulatory region of HdHSF1 was characterized, and the relative promoter activity was examined by dual-luciferase reporter gene assay system in HEK293T cell lines. Results After the inhibition of the H. diversicolor HSF1 gene (HdHSF1) by dsRNA (double-stranded RNA), the expression of most heat shock related-genes was down-regulated (p < 0.05). It indicated the importance of HdHSF1 in the heat shock response of H. diversicolor. Meanwhile, 5′-flanking region sequence (2633 bp) of the HdHSF1 gene was cloned; it contained a putative core promoter region, TATA box, CAAT box, CpG island, and many transcription elements. In HEK293T cells, the 5′-flanking region sequence can drive expression of the enhanced green fluorescent protein (EGFP), proving its promoter function. Exposure of cells to the high-temperature (39 °C and 42 °C) resulted in the activation of HdHSF1 promoter activity, which may explain why the expression of the HdHSF1 gene participates in heat shock response. Luciferase activity of different recombinant plasmids, which contained different truncated promoter fragments of the HdHSF1 gene in HEK293T cells, revealed the possible active regions of the promoter. To further identify the binding site of the critical transcription factor in the region, an expression vector with the site-directed mutation was constructed. After being mutated on the GATA-1 binding site, we found that the luciferase activity was significantly increased, which suggested that the GATA-1 binding site has a certain weakening effect on the activity of the HdHSF1 promoter. Conclusions These findings suggest that GATA-1 may be one of the transcription factors of HdHSF1, and a possible signaling pathway mediated by HdHSF1 may exist in H. diversicolor to counteract the adverse effects of heat shock stress.


Author(s):  
Bernadett Kalmar ◽  
Linda Greensmith

AbstractPharmacological up-regulation of heat shock proteins (hsps) rescues motoneurons from cell death in a mouse model of amyotrophic lateral sclerosis. However, the relationship between increased hsp expression and neuronal survival is not straightforward. Here we examined the effects of two pharmacological agents that induce the heat shock response via activation of HSF-1, on stressed primary motoneurons in culture. Although both arimoclomol and celastrol induced the expression of Hsp70, their effects on primary motoneurons in culture were significantly different. Whereas arimoclomol had survival-promoting effects, rescuing motoneurons from staurosporin and H2O2 induced apoptosis, celastrol not only failed to protect stressed motoneurons from apoptosis under same experimental conditions, but was neurotoxic and induced neuronal death. Immunostaining of celastrol-treated cultures for hsp70 and activated caspase-3 revealed that celastrol treatment activates both the heat shock response and the apoptotic cell death cascade. These results indicate that not all agents that activate the heat shock response will necessarily be neuroprotective.


1985 ◽  
Vol 5 (7) ◽  
pp. 1571-1581 ◽  
Author(s):  
W J Welch ◽  
J R Feramisco

Mammalian cells show a complex series of transcriptional and translational switching events in response to heat shock treatment which ultimately lead to the production and accumulation of a small number of proteins, the so-called heat shock (or stress) proteins. We investigated the heat shock response in both qualitative and quantitative ways in cells that were pretreated with drugs that specifically disrupt one or more of the three major cytoskeletal networks. (These drugs alone, cytochalasin E and colcemid, do not result in induction of the heat shock response.) Our results indicated that disruption of the actin microfilaments, the vimentin-containing intermediate filaments, or the microtubules in living cells does not hinder the ability of the cell to undergo an apparently normal heat shock response. Even when all three networks were simultaneously disrupted (resulting in a loose, baglike appearance of the cells), the cells still underwent a complete heat shock response as assayed by the appearance of the heat shock proteins. In addition, the major induced 72-kilodalton heat shock protein was efficiently translocated from the cytoplasm into its proper location in the nucleus and nucleolus irrespective of the condition of the three cytoskeletal elements.


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