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

1998 ◽  
Vol 111 (22) ◽  
pp. 3357-3365 ◽  
Author(s):  
C.I. Holmberg ◽  
P.M. Roos ◽  
J.M. Lord ◽  
J.E. Eriksson ◽  
L. Sistonen

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.

2007 ◽  
Vol 189 (24) ◽  
pp. 8818-8827 ◽  
Author(s):  
Diana L. Williams ◽  
Tana L. Pittman ◽  
Mike Deshotel ◽  
Sandra Oby-Robinson ◽  
Issar Smith ◽  
...  

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.


2006 ◽  
Vol 84 (5) ◽  
pp. 703-712 ◽  
Author(s):  
Silvia Fossati ◽  
Laura Formentini ◽  
Zhao-Qi Wang ◽  
Flavio Moroni ◽  
Alberto Chiarugi

Poly(ADP-ribose) polymerase-1 (PARP-1)-dependent poly(ADP-ribose) formation is emerging as a key regulator of transcriptional regulation, even though the targets and underlying molecular mechanisms have not yet been clearly identified. In this study, we gathered information on the role of PARP-1 activity in the heat shock response of mouse fibroblasts. We show that DNA binding of heat shock factor (HSF)-1 was impaired by PARP-1 activity in cellular extracts, and was higher in PARP-1−/− than in PARP-1+/+ cells. No evidence for HSF-1 poly(ADP-ribosyl)ation or PARP-1 interaction was found, but a poly(ADP-ribose) binding motif was identified in the transcription factor amino acid sequence. Consistent with data on HSF-1, the expression of heat-shock protein (HSP)-70 and HSP–27 was facilitated in cells lacking PARP-1. Thermosensitivity, however, was higher in PARP-1−/− than in PARP-1+/+ cells. Accordingly, we report that heat-shocked PARP-1 null fibroblasts showed an increased activation of proapoptotic JNK and decreased transcriptional efficiency of prosurvival NF-κB compared with wild-type counterparts. The data indicate that poly(ADP-ribosyl)ation finely regulates HSF-1 activity, and emphasize the complex role of PARP-1 in the heat-shock response of mammalian cells.


2009 ◽  
Vol 37 (1) ◽  
pp. 123-126 ◽  
Author(s):  
Charlotte R. Cooper ◽  
Amanda J. Daugherty ◽  
Sabrina Tachdjian ◽  
Paul H. Blum ◽  
Robert M. Kelly

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.


2010 ◽  
Vol 192 (7) ◽  
pp. 1999-2005 ◽  
Author(s):  
Amalia Porta ◽  
Annamaria Eletto ◽  
Zsolt Török ◽  
Silvia Franceschelli ◽  
Attila Glatz ◽  
...  

ABSTRACT So far attenuation of pathogens has been mainly obtained by chemical or heat treatment of microbial pathogens. Recently, live attenuated strains have been produced by genetic modification. We have previously demonstrated that in several prokaryotes as well as in yeasts and mammalian cells the heat shock response is controlled by the membrane physical state (MPS). We have also shown that in Salmonella enterica serovar Typhimurium LT2 (Salmonella Typhimurium) overexpression of a Δ12-desaturase gene alters the MPS, inducing a sharp impairment of transcription of major heat shock genes and failure of the pathogen to grow inside macrophage (MΦ) (A. Porta et al., J. Bacteriol. 192:1988-1998, 2010). Here, we show that overexpression of a homologous Δ9-desaturase sequence in the highly virulent G217B strain of the human fungal pathogen Histoplasma capsulatum causes loss of its ability to survive and persist within murine MΦ along with the impairment of the heat shock response. When the attenuated strain of H. capsulatum was injected in a mouse model of infection, it did not cause disease. Further, treated mice were protected when challenged with the virulent fungal parental strain. Attenuation of virulence in MΦ of two evolutionarily distant pathogens was obtained by genetic modification of the MPS, suggesting that this is a new method that may be used to produce attenuation or loss of virulence in both other intracellular prokaryotic and eukaryotic pathogens. This new procedure to generate attenuated forms of pathogens may be used eventually to produce a novel class of vaccines based on the genetic manipulation of a pathogen's membrane fluid state and stress response.


Virology ◽  
2010 ◽  
Vol 406 (2) ◽  
pp. 336-341 ◽  
Author(s):  
Yulia V. Lyupina ◽  
Svetlana B. Dmitrieva ◽  
Anna V. Timokhova ◽  
Svetlana N. Beljelarskaya ◽  
Olga G. Zatsepina ◽  
...  

1992 ◽  
Vol 70 (3-4) ◽  
pp. 207-214 ◽  
Author(s):  
Eduardo J. Patriarca ◽  
George S. Kobayashi ◽  
Bruno Maresca

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.


Oncogene ◽  
2003 ◽  
Vol 22 (1) ◽  
pp. 10-27 ◽  
Author(s):  
Yong Xian Ma ◽  
Saijun Fan ◽  
Jingbo Xiong ◽  
Ren-qi Yuan ◽  
Qinghui Meng ◽  
...  

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