Influence of proteasome and redox state on heat shock-induced activation of stress kinases, AP-1 and HSF

Tacchini, Lorenza; Dansi, Paola; Matteucci, Emanuela; Bernelli‐Zazzera, Aldo; Desiderio, Maria Alfonsina

doi:10.1016/s0167-4889(00)00141-5

Cited by 11 publications

(8 citation statements)

References 49 publications

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“…ATP-dependent HSP90 was shown to protect the trypsin-like activity of the proteasome system from oxidative inactivation (9) and to inhibit the activity of the proteasome (4,15,33). Proteasome inhibitors activate heat shock transcription factors, with the subsequent induction of HSPs (55,56); e.g., the exposure of U373 MG human glioma cells to proteasome inhibitors induces HSF2-mediated accumulation of HSP27 (38). In the present study, we identified another relationship between the ubiquitin-proteasome pathway and HSP27.…”

Section: Discussionmentioning

confidence: 99%

HSP27 Is a Ubiquitin-Binding Protein Involved in I-κBα Proteasomal Degradation

Parcellier

Schmitt

Gurbuxani

et al. 2003

Molecular and Cellular Biology

309

257

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HSP27 is an ATP-independent chaperone that confers protection against apoptosis through various mechanisms, including a direct interaction with cytochrome c. Here we show that HSP27 overexpression in various cell types enhances the degradation of ubiquitinated proteins by the 26S proteasome in response to stressful stimuli, such as etoposide or tumor necrosis factor alpha (TNF-␣). We demonstrate that HSP27 binds to polyubiquitin chains and to the 26S proteasome in vitro and in vivo. The ubiquitin-proteasome pathway is involved in the activation of transcription factor NF-B by degrading its main inhibitor, I-B␣. HSP27 overexpression increases NF-B nuclear relocalization, DNA binding, and transcriptional activity induced by etoposide, ⌻NF-␣, and interleukin 1␤. HSP27 does not affect I-B␣ phosphorylation but enhances the degradation of phosphorylated I-B␣ by the proteasome. The interaction of HSP27 with the 26S proteasome is required to activate the proteasome and the degradation of phosphorylated I-B␣. A protein complex that includes HSP27, phosphorylated I-B␣, and the 26S proteasome is formed. Based on these observations, we propose that HSP27, under stress conditions, favors the degradation of ubiquitinated proteins, such as phosphorylated I-B␣. This novel function of HSP27 would account for its antiapoptotic properties through the enhancement of NF-B activity.

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Section: Discussionmentioning

confidence: 99%

HSP27 Is a Ubiquitin-Binding Protein Involved in I-κBα Proteasomal Degradation

Parcellier

Schmitt

Gurbuxani

et al. 2003

Molecular and Cellular Biology

309

257

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“…It has already been shown that cells respond to exposure to elevated temperatures by increasing production of Hsps (heat‐shock proteins) such as Hsp70, Hsp27 and Akt (also known as protein kinase B) [23,27]. p38 MAPK, a member of the family of MAPKs, is essential for the triggering of Hsp expression by heat stress [7,24,28]. Various physical stimuli have been demonstrated to activate p38 MAPK [7], suggesting that activation of p38 MAPK is an essential step for formation of an HA‐mediated 3D‐like proliferation pattern of mouse fibroblasts in response to physical stimulation.…”

Section: Discussionmentioning

confidence: 99%

Heat‐shock‐induced three‐dimensional‐like proliferation of mouse fibroblasts mediated by hydroxyapatite

Hiragami

Akiyama

Koike

et al. 2007

Biotech and App Biochem

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The aim of the present study was to determine both the minimal and the optimal conditions under which heat treatment is effective for enhancing 3D (three-dimensional)-like cell proliferation. C3H10T1/2 mouse fibroblasts were cultured with hydroxyapatite granules for 10 weeks after heat treatment at 40, 41.5, 43, 44 or 45 degrees C for 2, 10, 15, 20, 30, 45, 60, 90, 180 and 360 min. Then minimal and optimal conditions of temperature and duration of heat treatment for induction of 3D-like proliferation of cells were determined. The minimal conditions of heat treatment to induce 3D-like proliferation were 43 degrees C for 2 min and the optimal conditions were 43 degrees C for 10 min. The mean rates of formation of 3D-like proliferation patterns by cells heat-treated at 43 degrees C for 2 and 10 min were significantly higher (1.7- and 3.7-fold respectively) than that by untreated cells (P<0.05). We also observed significantly greater effects of heat treatment on 3D-like proliferation at 40 degrees C for 90 or 180 min and at 41.5 degrees C for 15 min and 44 degrees C for 10 min. We found that apoptosis had occurred in 7.5 and 87.0% of the cells at 1 week after heat treatment at 43 degrees C for 10 min and 30 min respectively. Western-blot analysis demonstrated that phosphorylation of p38 MAPK (mitogen-activated protein kinase) was markedly increased by heat treatment at 43 degrees C for 10 min. These findings suggest that activation of p38 MAPK by heat shock is associated with 3D-like cell proliferation. The results of the present study should be useful for further studies aimed at elucidation of the physiological mechanisms underlying thermotherapy and hyperthermia.

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“…36 For these reasons, activation of stress-related cascades is one of the factors thought to be involved in proteasome inhibitor-mediated lethality. 37 Moreover, interference with MEK/ERK signaling (ie, by pharmacologic MEK inhibitors) has recently been shown to promote the lethal actions of proteasome inhibitors. 38 It is noteworthy that exposure of K562 cells to HDIs resulted in down-regulation of the Raf/MEK/ERK cascade, in agreement with previous reports demonstrating similar events in depsipeptide-treated non-small cell lung cancer cells.…”

Section: Discussionmentioning

confidence: 99%