scholarly journals Intramolecular Repression of Mouse Heat Shock Factor 1

1998 ◽  
Vol 18 (2) ◽  
pp. 906-918 ◽  
Author(s):  
Thomas Farkas ◽  
Yulia A. Kutskova ◽  
Vincenzo Zimarino
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Mammalian Cells ◽  
Coiled Coil ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Reticulocyte Lysate ◽  
Heptad Repeats ◽  
Intramolecular Mechanism

ABSTRACT The pathway leading to transcriptional activation of heat shock genes involves a step of heat shock factor 1 (HSF1) trimerization required for high-affinity binding of this activator protein to heat shock elements (HSEs) in the promoters. Previous studies have shown that in vivo the trimerization is negatively regulated at physiological temperatures by a mechanism that requires multiple hydrophobic heptad repeats (HRs) which may form a coiled coil in the monomer. To investigate the minimal requirements for negative regulation, in this work we have examined mouse HSF1 translated in rabbit reticulocyte lysate or extracted from Escherichia coli after limited expression. We show that under these conditions HSF1 behaves as a monomer which can be induced by increases in temperature to form active HSE-binding trimers and that mutations of either HR region cause activation in both systems. Furthermore, temperature elevations and acidic buffers activate purified HSF1, and mild proteolysis excises fragments which form HSE-binding oligomers. These results suggest that oligomerization can be repressed in the monomer, as previously proposed, and that repression can be relieved in the apparent absence of regulatory proteins. An intramolecular mechanism may be central for the regulation of this transcription factor in mammalian cells, although not necessarily sufficient.

scholarly journals HSP90 Interacts with and Regulates the Activity of Heat Shock Factor 1 in Xenopus Oocytes

1998 ◽  
Vol 18 (9) ◽  
pp. 4949-4960 ◽  
Author(s):  
Adnan Ali ◽  
Steven Bharadwaj ◽  
Ruth O’Carroll ◽  
Nick Ovsenek
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Cellular Signaling ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Heat Shock Element ◽  
Nuclear Extracts ◽  
Multistep Process

ABSTRACT Transcriptional activation of heat shock genes is a reversible and multistep process involving conversion of inactive heat shock factor 1 (HSF1) monomers into heat shock element (HSE)-binding homotrimers, hyperphosphorylation, and further modifications that induce full transcriptional competence. HSF1 is controlled by multiple regulatory mechanisms, including suppression by additional cellular factors, physical interactions with HSP70, and integration into different cellular signaling cascades. However, the signaling mechanisms by which cells respond to stress and control the HSF1 activation-deactivation pathway are not known. Here we demonstrate that HSP90, a cellular chaperone known to regulate several signal transduction molecules and transcription factors, functions in the regulation of HSF1. The existence of HSF1-HSP90 heterocomplexes was shown by coimmunoprecipitation of HSP90 with HSF1 from unshocked and heat-shocked nuclear extracts, recognition of HSF1-HSE complexes in vitro by using HSP90 antibodies (Abs), and recognition of HSF1 in vivo by HSP90 Abs microinjected directly into oocyte nuclei. The functional impact of HSP90-HSF1 interactions was analyzed by using two strategies: direct nuclear injection of HSP90 Abs and treatment of cells with geldanamycin (GA), an agent that specifically blocks the chaperoning activity of HSP90. Both HSP90 Abs and GA delayed the disassembly of HSF1 trimers during recovery from heat shock and specifically inhibited heat-induced transcription from a chloramphenicol acetyltransferase reporter construct under control of the hsp70 promoter. HSP90 Abs activated HSE binding in the absence of heat shock, an effect that could be reversed by subsequent injection of purified HSP90. GA did not activate HSE binding under nonshock conditions but increased the quantity of HSE binding induced by heat shock. On the basis of these findings and the known properties of HSP90, we propose a new regulatory model in which HSP90 participates in modulating HSF1 at different points along the activation-deactivation pathway, influencing the interconversion between monomeric and trimeric conformations as well as transcriptional activation. We also put forth the hypothesis that HSP90 links HSF1 to cellular signaling molecules coordinating the stress response.

scholarly journals Phosphorylation of Serine 303 Is a Prerequisite for the Stress-Inducible SUMO Modification of Heat Shock Factor 1

2003 ◽  
Vol 23 (8) ◽  
pp. 2953-2968 ◽  
Author(s):  
Ville Hietakangas ◽  
Johanna K. Ahlskog ◽  
Annika M. Jakobsson ◽  
Maria Hellesuo ◽  
Niko M. Sahlberg ◽  
...  
Keyword(s):  
Heat Shock ◽  
Phosphorylation Site ◽  
Stress Granules ◽  
Heat Shock Factor ◽  
Transcriptional Level ◽  
Heat Shock Factor 1 ◽  
Protection Mechanism ◽  
Sumo Modification

ABSTRACT The heat shock response, which is accompanied by a rapid and robust upregulation of heat shock proteins (Hsps), is a highly conserved protection mechanism against protein-damaging stress. Hsp induction is mainly regulated at transcriptional level by stress-inducible heat shock factor 1 (HSF1). Upon activation, HSF1 trimerizes, binds to DNA, concentrates in the nuclear stress granules, and undergoes a marked multisite phosphorylation, which correlates with its transcriptional activity. In this study, we show that HSF1 is modified by SUMO-1 and SUMO-2 in a stress-inducible manner. Sumoylation is rapidly and transiently enhanced on lysine 298, located in the regulatory domain of HSF1, adjacent to several critical phosphorylation sites. Sumoylation analyses of HSF1 phosphorylation site mutants reveal that specifically the phosphorylation-deficient S303 mutant remains devoid of SUMO modification in vivo and the mutant mimicking phosphorylation of S303 promotes HSF1 sumoylation in vitro, indicating that S303 phosphorylation is required for K298 sumoylation. This finding is further supported by phosphopeptide mapping and analysis with S303/7 phosphospecific antibodies, which demonstrate that serine 303 is a target for strong heat-inducible phosphorylation, corresponding to the inducible HSF1 sumoylation. A transient phosphorylation-dependent colocalization of HSF1 and SUMO-1 in nuclear stress granules provides evidence for a strictly regulated subnuclear interplay between HSF1 and SUMO.

Constitutive binding of yeast heat shock factor to DNA in vivo

1988 ◽  
Vol 8 (11) ◽  
pp. 5040-5042
Author(s):  
B K Jakobsen ◽  
H R Pelham
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Heat Shock Factor ◽  
Promoter Element ◽  
Synthetic Promoter

We measured the binding of yeast heat shock factor (HSF) to DNA in vivo by using an interference assay in which HSF excludes GAL4 from a synthetic promoter element containing overlapping binding sites for each protein. The results show that HSF binds to DNA in unstressed cells and that binding is not sufficient for transcriptional activation.

Inhibition of Heat Shock Factor 1 Enhances Repressive Molecular Mechanisms on the POMC Promoter

2019 ◽  
Vol 109 (4) ◽  
pp. 362-373
Author(s):  
Denis Ciato ◽  
Ran Li ◽  
Jose Luis Monteserin Garcia ◽  
Lilia Papst ◽  
Sarah D’Annunzio ◽  
...  
Keyword(s):  
Heat Shock ◽  
Clinical Features ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Primary Cultures ◽  
Heat Shock Protein 90 ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1 ◽  
Promising Treatment ◽  
Acth Secreting

Background: Cushing’s disease (CD) is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary tumours. They express high levels of heat shock protein 90 and heat shock factor 1 (HSF1) in comparison to the normal tissue counterpart, indicating activated cellular stress. Aims: Our objectives were: (1) to correlate HSF1 expression with clinical features and hormonal/radiological findings of CD, and (2) to investigate the effects of HSF1 inhibition as a target for CD treatment. Patients/Methods: We examined the expression of total and pSer326HSF1 (marker for its transcriptional activation) by Western blot on eight human CD tumours and compared to the HSF1 status of normal pituitary. We screened a cohort of 45 patients with CD for HSF1 by immunohistochemistry and correlated the HSF1 immunoreactivity score with the available clinical data. We evaluated the effects of HSF1 silencing with RNA interference and the HSF1 inhibitor KRIBB11 in AtT-20 cells and four primary cultures of human corticotroph tumours. Results: We show that HSF1 protein is highly expressed and transcriptionally active in CD tumours in comparison to normal pituitary. The immunoreactivity score for HSF1 did not correlate with the typical clinical features of the disease. HSF1 inhibition reduced proopiomelanocortin (Pomc) transcription in AtT-20 cells. The HSF1 inhibitor KRIBB11 suppressed ACTH synthesis from 75% of human CD tumours in primary cell culture. This inhibitory action on Pomc transcription was mediated by increased glucocorticoid receptor and suppressed Nurr77/Nurr1 and AP-1 transcriptional activities. Conclusions: These data show that HSF1 regulates POMC transcription. Pharmacological targeting of HSF1 may be a promising treatment option for the control of excess ACTH secretion in CD.

scholarly journals Inhibition of the activation of heat shock factor in vivo and in vitro by flavonoids.

1992 ◽  
Vol 12 (8) ◽  
pp. 3490-3498 ◽  
Author(s):  
N Hosokawa ◽  
K Hirayoshi ◽  
H Kudo ◽  
H Takechi ◽  
A Aoike ◽  
...  
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Heat Shock Factor ◽  
Mobility Shift ◽  
Human Colon Cancer ◽  
Heat Shock Element ◽  
Mrna Accumulation ◽  
Cell Extracts

Transcriptional activation of human heat shock protein (HSP) genes by heat shock or other stresses is regulated by the activation of a heat shock factor (HSF). Activated HSF posttranslationally acquires DNA-binding ability. We previously reported that quercetin and some other flavonoids inhibited the induction of HSPs in HeLa and COLO 320DM cells, derived from a human colon cancer, at the level of mRNA accumulation. In this study, we examined the effects of quercetin on the induction of HSP70 promoter-regulated chloramphenicol acetyltransferase (CAT) activity and on the binding of HSF to the heat shock element (HSE) by a gel mobility shift assay with extracts of COLO 320DM cells. Quercetin inhibited heat-induced CAT activity in COS-7 and COLO 320DM cells which were transfected with plasmids bearing the CAT gene under the control of the promoter region of the human HSP70 gene. Treatment with quercetin inhibited the binding of HSF to the HSE in whole-cell extracts activated in vivo by heat shock and in cytoplasmic extracts activated in vitro by elevated temperature or by urea. The binding of HSF activated in vitro by Nonidet P-40 was not suppressed by the addition of quercetin. The formation of the HSF-HSE complex was not inhibited when quercetin was added only during the binding reaction of HSF to the HSE after in vitro heat activation. Quercetin thus interacts with HSF and inhibits the induction of HSPs after heat shock through inhibition of HSF activation.

scholarly journals Heat Shock Factor 1 Represses Ras-induced Transcriptional Activation of the c-fosGene

1997 ◽  
Vol 272 (43) ◽  
pp. 26803-26806 ◽  
Author(s):  
Changmin Chen ◽  
Yue Xie ◽  
Mary Ann Stevenson ◽  
Philip E. Auron ◽  
Stuart K. Calderwood
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Heat Shock Factor ◽  
Heat Shock Factor 1

Poly(ADP-ribosyl)ation regulates heat shock factor-1 activity and the heat shock response in murine fibroblasts

2006 ◽  
Vol 84 (5) ◽  
pp. 703-712 ◽  
Author(s):  
Silvia Fossati ◽  
Laura Formentini ◽  
Zhao-Qi Wang ◽  
Flavio Moroni ◽  
Alberto Chiarugi
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Heat Shock Factor ◽  
Binding Motif ◽  
Heat Shock Factor 1 ◽  
Shock Response ◽  
Parp 1

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.

scholarly journals Constitutive binding of yeast heat shock factor to DNA in vivo.

1988 ◽  
Vol 8 (11) ◽  
pp. 5040-5042 ◽  
Author(s):  
B K Jakobsen ◽  
H R Pelham
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Heat Shock Factor ◽  
Promoter Element ◽  
Synthetic Promoter

We measured the binding of yeast heat shock factor (HSF) to DNA in vivo by using an interference assay in which HSF excludes GAL4 from a synthetic promoter element containing overlapping binding sites for each protein. The results show that HSF binds to DNA in unstressed cells and that binding is not sufficient for transcriptional activation.

scholarly journals Identification of heat-inducible long noncoding RNA MALAT1-containing novel nuclear (HiNoCo) body

2021 ◽  
Author(s):  
Rena Onoguchi-Mizutani ◽  
Yoshitaka Kirikae ◽  
Yoko Ogura ◽  
Tony Gutschner ◽  
Sven Diederichs ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Long Noncoding Rna ◽  
Mammalian Cells ◽  
Noncoding Rna ◽  
Heat Shock Factor ◽  
Nuclear Bodies ◽  
Cajal Body ◽  
Heat Shock Factor 1 ◽  
Shock Response

The heat shock response is critical for the survival of all organisms. Metastasis-associated long adenocarcinoma transcript 1 (MALAT1) is a long noncoding RNA localized in nuclear speckles, but its physiological role remains elusive. Here, we show that heat shock induces translocation of MALAT1 to a distinct nuclear body named heat shock-inducible noncoding RNA-containing nuclear (HiNoCo) body in mammalian cells. The MALAT1 knockout A549 cells showed reduced proliferation after heat shock. The HiNoCo body, formed by a nearby nuclear speckle, is distinct from any other known nuclear bodies, including the nuclear stress body, Cajal body, germs, paraspeckles, nucleoli, and promyelocytic leukemia body. The formation of HiNoCo body is reversible and independent of heat shock factor 1, the master transcription regulator of the heat shock response. Our results suggest the HiNoCo body participates in heat shock factor 1-independent heat shock responses in mammalian cells.

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