Faculty Opinions recommendation of Characterizing HSF1 Binding and Post-Translational Modifications of hsp70 Promoter in Cultured Cortical Neurons: Implications in the Heat-Shock Response.

ABSTRACTC-terminus of HSC70-interacting protein (CHIP) encoded by the gene STUB1 is a co-chaperone and E3 ligase that acts as a key regulator of cellular protein homeostasis. Mutations in STUB1 cause autosomal recessive spinocerebellar ataxia type 16 (SCAR16) with widespread neurodegeneration manifesting as spastic-ataxic gait disorder, dementia and epilepsy. CHIP−/− mice display severe cerebellar atrophy, show high perinatal lethality and impaired heat stress tolerance. To decipher the pathomechanism underlying SCAR16, we investigated the heat shock response (HSR) in primary fibroblasts of three SCAR16 patients. We found impaired HSR induction and recovery compared to healthy controls. HSPA1A/B transcript levels (coding for HSP70) were reduced upon heat shock but HSP70 remained higher upon recovery in patient- compared to control-fibroblasts. As SCAR16 primarily affects the central nervous system we next investigated the HSR in cortical neurons (CNs) derived from induced pluripotent stem cells of SCAR16 patients. We found CNs of patients and controls to be surprisingly resistant to heat stress with high basal levels of HSP70 compared to fibroblasts. Although heat stress resulted in strong transcript level increases of many HSPs, this did not translate into higher HSP70 protein levels upon heat shock, independent of STUB1 mutations. Furthermore, STUB1(−/−) neurons generated by CRISPR/Cas9-mediated genome editing from an isogenic healthy control line showed a similar HSR to patients. Proteomic analysis of CNs showed dysfunctional protein (re)folding and higher basal oxidative stress levels in patients. Our results question the role of impaired HSR in SCAR16 neuropathology and highlight the need for careful selection of proper cell types for modeling human diseases.

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Mathematical Modeling of the Eukaryotic Heat-Shock Response: Dynamics of the hsp70 Promoter

Biophysical Journal ◽

10.1529/biophysj.104.055301 ◽

2005 ◽

Vol 88 (3) ◽

pp. 1646-1658 ◽

Cited By ~ 62

Author(s):

Theodore R. Rieger ◽

Richard I. Morimoto ◽

Vassily Hatzimanikatis

Keyword(s):

Mathematical Modeling ◽

Heat Shock ◽

Heat Shock Response ◽

Response Dynamics ◽

Hsp70 Promoter ◽

Shock Response

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Heat shock stimulation of a tilapia heat shock protein 70 promoter is mediated by a distal element

Biochemical Journal ◽

10.1042/bj3560353 ◽

2001 ◽

Vol 356 (2) ◽

pp. 353-359 ◽

Cited By ~ 6

Author(s):

Alfredo MOLINA ◽

Emmanuel Di MARTINO ◽

Joseph A. MARTIAL ◽

Marc MULLER

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Transient Expression ◽

Heat Shock Response ◽

Heat Shock Protein 70 ◽

Zebrafish Embryos ◽

Epithelioma Papulosum Cyprini ◽

Hsp70 Promoter ◽

Shock Response ◽

Constitutive Factor

We reported previously that a tilapia (Oreochromis mossambicus) heat shock protein 70 (HSP70) promoter is able to confer heat shock response on a reporter gene after transient expression both in cell culture and in microinjected zebrafish embryos. Here we present the first functional analysis of a fish HSP70 promoter, the tiHSP70 promoter. Using transient expression experiments in carp EPC (epithelioma papulosum cyprini) cells and in microinjected zebrafish embryos, we show that a distal heat shock response element (HSE1) at approx. −800 is predominantly responsible for the heat shock response of the tiHSP70 promoter. This element specifically binds an inducible transcription factor, most probably heat shock factor, and a constitutive factor. The constitutive complex is not observed with the non-functional, proximal HSE3 sequence, suggesting that both factors are required for the heat shock response mediated by HSE1.

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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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