Role of vapBC toxin–antitoxin loci in the thermal stress response of Sulfolobus solfataricus

TA (toxin–antitoxin) loci are ubiquitous in prokaryotic micro-organisms, including archaea, yet their physiological function is largely unknown. For example, preliminary reports have suggested that TA loci are microbial stress-response elements, although it was recently shown that knocking out all known chromosomally located TA loci in Escherichia coli did not have an impact on survival under certain types of stress. The hyperthermophilic crenarchaeon Sulfolobus solfataricus encodes at least 26 vapBC (where vap is virulence-associated protein) family TA loci in its genome. VapCs are PIN (PilT N-terminus) domain proteins with putative ribonuclease activity, while VapBs are proteolytically labile proteins, which purportedly function to silence VapCs when associated as a cognate pair. Global transcriptional analysis of S. solfataricus heat-shock-response dynamics (temperature shift from 80 to 90°C) revealed that several vapBC genes were triggered by the thermal shift, suggesting a role in heat-shock-response. Indeed, knocking out a specific vapBC locus in S. solfataricus substantially changed the transcriptome and, in one case, rendered the crenarchaeon heat-shock-labile. These findings indicate that more work needs to be done to determine the role of VapBCs in S. solfataricus and other thermophilic archaea, especially with respect to post-transcriptional regulation.

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Dynamic Metabolic Adjustments and Genome Plasticity Are Implicated in the Heat Shock Response of the Extremely Thermoacidophilic Archaeon Sulfolobus solfataricus

Journal of Bacteriology ◽

10.1128/jb.00080-06 ◽

2006 ◽

Vol 188 (12) ◽

pp. 4553-4559 ◽

Cited By ~ 48

Author(s):

Sabrina Tachdjian ◽

Robert M. Kelly

Keyword(s):

Stress Response ◽

Heat Shock ◽

Metabolic Regulation ◽

Sulfolobus Solfataricus ◽

Temperature Shift ◽

Open Reading Frames ◽

Genome Plasticity ◽

Shock Response ◽

Insertion Elements ◽

Reading Frames

ABSTRACT Approximately one-third of the open reading frames encoded in the Sulfolobus solfataricus genome were differentially expressed within 5 min following an 80 to 90°C temperature shift at pH 4.0. This included many toxin-antitoxin loci and insertion elements, implicating a connection between genome plasticity and metabolic regulation in the early stages of stress response.

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Conventional and novel PKC isoenzymes modify the heat-induced stress response but are not activated by heat shock

Journal of Cell Science ◽

10.1242/jcs.111.22.3357 ◽

1998 ◽

Vol 111 (22) ◽

pp. 3357-3365 ◽

Cited By ~ 1

Author(s):

C.I. Holmberg ◽

P.M. Roos ◽

J.M. Lord ◽

J.E. Eriksson ◽

L. Sistonen

Keyword(s):

Stress Response ◽

Heat Shock ◽

Heat Shock Response ◽

Mammalian Cells ◽

Elevated Temperatures ◽

Heat Shock Element ◽

Post Translational Modifications ◽

Induced Stress ◽

Shock Response

In mammalian cells, the heat-induced stress response is mediated by the constitutively expressed heat shock transcription factor 1 (HSF1). Upon exposure to elevated temperatures, HSF1 undergoes several post-translational modifications, including inducible phosphorylation or hyperphosphorylation. To date, neither the role of HSF1 hyperphosphorylation in regulation of the transcriptional activity of HSF1 nor the signaling pathways involved have been characterized. We have previously shown that the protein kinase C (PKC) activator, 12-O-tetradecanoylphorbol 13-acetate (TPA), markedly enhances the heat-induced stress response, and in the present study we elucidate the mechanism by which PKC activation affects the heat shock response in human cells. Our results show that several conventional and novel PKC isoenzymes are activated during the TPA-mediated enhancement of the heat shock response and that the enhancement can be inhibited by the specific PKC inhibitor bisindolylmaleimide I. Furthermore, the potentiating effect of TPA on the heat-induced stress response requires an intact heat shock element in the hsp70 promoter, indicating that PKC-responsive pathways are able to modulate the activity of HSF1. We also demonstrate that PKC is not activated by heat stress per se. These results reveal that PKC exhibits a significant modulatory role of the heat-induced stress response, but is not directly involved in regulation of the heat shock response.

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Allograft injury mediated by reactive oxygen species: from conserved proteins of Drosophila to acute and chronic rejection of human transplants. Part II: Role of reactive oxygen species in the induction of the heat shock response as a regulator of innate

Transplantation Reviews ◽

10.1053/trre.2003.2 ◽

2003 ◽

Vol 17 (1) ◽

pp. 31-44 ◽

Cited By ~ 12

Author(s):

Walter Land

Keyword(s):

Reactive Oxygen Species ◽

Heat Shock ◽

Heat Shock Response ◽

Chronic Rejection ◽

Reactive Oxygen ◽

Oxygen Species ◽

Shock Response

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An important role of the heat shock response in infected cells for replication of baculoviruses

Virology ◽

10.1016/j.virol.2010.07.039 ◽

2010 ◽

Vol 406 (2) ◽

pp. 336-341 ◽

Cited By ~ 30

Author(s):

Yulia V. Lyupina ◽

Svetlana B. Dmitrieva ◽

Anna V. Timokhova ◽

Svetlana N. Beljelarskaya ◽

Olga G. Zatsepina ◽

...

Keyword(s):

Heat Shock ◽

Heat Shock Response ◽

Shock Response ◽

Infected Cells

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Mitochondrial activity and heat-shock response during morphogenesis in the pathogenic fungus Histoplasma capsulatum

Biochemistry and Cell Biology ◽

10.1139/o92-031 ◽

1992 ◽

Vol 70 (3-4) ◽

pp. 207-214 ◽

Cited By ~ 17

Author(s):

Eduardo J. Patriarca ◽

George S. Kobayashi ◽

Bruno Maresca

Keyword(s):

Heat Shock ◽

Heat Shock Response ◽

Elevated Temperatures ◽

Histoplasma Capsulatum ◽

Pathogenic Fungus ◽

Temperature Shift ◽

Mitochondrial Activity ◽

Mitochondrial Atpase ◽

Heat Shock Genes ◽

Shock Response

Changes in temperature and a variety of other stimuli coordinately induce transcription of a specific set of heat-shock genes in all organisms. In the human fungal pathogen Histoplasma capsulatum, a temperature shift from 25 to 37 °C acts not only as a signal that causes transcription of heat-shock genes, but also triggers a morphological mycelium-to yeast-phase transition. The temperature-induced morphological transition may be viewed as a heat-shock response followed by cellular adaptation to a higher temperature. We have found that by inducing thermotolerance, i.e., an initial incubation at 34 °C, the thermosensitive attenuated Downs strain of H. capsulatum can be made to resemble those of the more temperature-tolerant G222B strain with respect to mitochondrial ATPase activity and electron transport efficiency at elevated temperatures. Furthermore, if the heat-shock response is first elicited by preincubation at milder temperatures or stress, transcription of heat-shock mRNA in mycelial cells of Downs strain that shifted to 37 °C proceeds at rates comparable to those of the virulent strains.Key words: heat shock, thermotolerance, ATPase, 70-kilodalton heat-shock protein, fungal morphogenesis.

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Role of BRCA1 in heat shock response

Oncogene ◽

10.1038/sj.onc.1206061 ◽

2003 ◽

Vol 22 (1) ◽

pp. 10-27 ◽

Cited By ~ 25

Author(s):

Yong Xian Ma ◽

Saijun Fan ◽

Jingbo Xiong ◽

Ren-qi Yuan ◽

Qinghui Meng ◽

...

Keyword(s):

Heat Shock ◽

Heat Shock Response ◽

Shock Response

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Molecular Basis of the Defective Heat Stress Response in Mycobacterium leprae

Journal of Bacteriology ◽

10.1128/jb.00601-07 ◽

2007 ◽

Vol 189 (24) ◽

pp. 8818-8827 ◽

Cited By ~ 15

Author(s):

Diana L. Williams ◽

Tana L. Pittman ◽

Mike Deshotel ◽

Sandra Oby-Robinson ◽

Issar Smith ◽

...

Keyword(s):

Heat Stress ◽

Stress Response ◽

Heat Shock ◽

Heat Shock Response ◽

Elevated Temperatures ◽

Transcriptional Response ◽

Mycobacterium Leprae ◽

Heat Stress Response ◽

Regulatory Circuits ◽

Shock Response

ABSTRACT Mycobacterium leprae, a major human pathogen, grows poorly at 37°C. The basis for its inability to survive at elevated temperatures was investigated. We determined that M. leprae lacks a protective heat shock response as a result of the lack of transcriptional induction of the alternative sigma factor genes sigE and sigB and the major heat shock operons, HSP70 and HSP60, even though heat shock promoters and regulatory circuits for these genes appear to be intact. M. leprae sigE was found to be capable of complementing the defective heat shock response of mycobacterial sigE knockout mutants only in the presence of a functional mycobacterial sigH, which orchestrates the mycobacterial heat shock response. Since the sigH of M. leprae is a pseudogene, these data support the conclusion that a key aspect of the defective heat shock response in M. leprae is the absence of a functional sigH. In addition, 68% of the genes induced during heat shock in M. tuberculosis were shown to be either absent from the M. leprae genome or were present as pseudogenes. Among these is the hsp/acr2 gene, whose product is essential for M. tuberculosis survival during heat shock. Taken together, these results suggest that the reduced ability of M. leprae to survive at elevated temperatures results from the lack of a functional transcriptional response to heat shock and the absence of a full repertoire of heat stress response genes, including sigH.

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