Abstract
Previous studies demonstrated that induction of the heat shock response is associated with inhibition of the proinflammatory transcription factor NF-κB by a mechanism involving inhibition of I-κBα degradation. To provide further insight regarding the interactions of these fundamental cellular responses, the present experiments were designed to elucidate the mechanism(s) by which heat shock inhibits degradation of I-κBα. In an in vitro model of inflammatory cell signaling, treatment of RAW 264.7 murine macrophages with LPS (100 ng/mL) caused rapid degradation of I-κBα. Heat shock, 1 h before treatment with LPS, completely inhibited LPS-mediated degradation of I-κBα. Immunoprecipitation studies demonstrated that heat shock inhibited LPS-mediated ubiquitination of I-κBα. Western-blot analyses using a phosphorylated I-κBα-specific antibody demonstrated that heat shock inhibited LPS-mediated phosphorylation of I-κBα. In contrast, heat shock induced phosphorylation of c-jun. In murine fibroblasts having genetic ablation of the heat shock factor-1 gene, heat shock inhibited tumor necrosis factor-α mediated degradation of I-κBα. We conclude that the mechanism by which heat shock inhibits LPS-mediated degradation of I-κBα involves specific inhibition of I-κBα phosphorylation and subsequent I-κBα ubiquitination. In addition, this mechanism does not involve activation of heat shock factor-1 or the heat shock proteins regulated by heat shock factor-1.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 447-450 |
| Number of pages | 4 |
| Journal | Shock |
| Volume | 14 |
| Issue number | 4 |
| State | Published - Oct 2000 |
| Externally published | Yes |
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Keywords
- Heat shock factor-1
- Inflammation
- Lipopolysaccharide
- NF-κB
- Signal transduction
- Stress response
ASJC Scopus subject areas
- Physiology
- Critical Care and Intensive Care Medicine
Cite this
Heat shock inhibits phosphorylation of I-κBα. / Shanley, Thomas P.; Ryan, Marnie A.; Eaves-Pyles, Tonyia; Wong, Hector R.
In: Shock, Vol. 14, No. 4, 10.2000, p. 447-450.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Heat shock inhibits phosphorylation of I-κBα
AU - Shanley, Thomas P.
AU - Ryan, Marnie A.
AU - Eaves-Pyles, Tonyia
AU - Wong, Hector R.
PY - 2000/10
Y1 - 2000/10
N2 - Previous studies demonstrated that induction of the heat shock response is associated with inhibition of the proinflammatory transcription factor NF-κB by a mechanism involving inhibition of I-κBα degradation. To provide further insight regarding the interactions of these fundamental cellular responses, the present experiments were designed to elucidate the mechanism(s) by which heat shock inhibits degradation of I-κBα. In an in vitro model of inflammatory cell signaling, treatment of RAW 264.7 murine macrophages with LPS (100 ng/mL) caused rapid degradation of I-κBα. Heat shock, 1 h before treatment with LPS, completely inhibited LPS-mediated degradation of I-κBα. Immunoprecipitation studies demonstrated that heat shock inhibited LPS-mediated ubiquitination of I-κBα. Western-blot analyses using a phosphorylated I-κBα-specific antibody demonstrated that heat shock inhibited LPS-mediated phosphorylation of I-κBα. In contrast, heat shock induced phosphorylation of c-jun. In murine fibroblasts having genetic ablation of the heat shock factor-1 gene, heat shock inhibited tumor necrosis factor-α mediated degradation of I-κBα. We conclude that the mechanism by which heat shock inhibits LPS-mediated degradation of I-κBα involves specific inhibition of I-κBα phosphorylation and subsequent I-κBα ubiquitination. In addition, this mechanism does not involve activation of heat shock factor-1 or the heat shock proteins regulated by heat shock factor-1.
AB - Previous studies demonstrated that induction of the heat shock response is associated with inhibition of the proinflammatory transcription factor NF-κB by a mechanism involving inhibition of I-κBα degradation. To provide further insight regarding the interactions of these fundamental cellular responses, the present experiments were designed to elucidate the mechanism(s) by which heat shock inhibits degradation of I-κBα. In an in vitro model of inflammatory cell signaling, treatment of RAW 264.7 murine macrophages with LPS (100 ng/mL) caused rapid degradation of I-κBα. Heat shock, 1 h before treatment with LPS, completely inhibited LPS-mediated degradation of I-κBα. Immunoprecipitation studies demonstrated that heat shock inhibited LPS-mediated ubiquitination of I-κBα. Western-blot analyses using a phosphorylated I-κBα-specific antibody demonstrated that heat shock inhibited LPS-mediated phosphorylation of I-κBα. In contrast, heat shock induced phosphorylation of c-jun. In murine fibroblasts having genetic ablation of the heat shock factor-1 gene, heat shock inhibited tumor necrosis factor-α mediated degradation of I-κBα. We conclude that the mechanism by which heat shock inhibits LPS-mediated degradation of I-κBα involves specific inhibition of I-κBα phosphorylation and subsequent I-κBα ubiquitination. In addition, this mechanism does not involve activation of heat shock factor-1 or the heat shock proteins regulated by heat shock factor-1.
KW - Heat shock factor-1
KW - Inflammation
KW - Lipopolysaccharide
KW - NF-κB
KW - Signal transduction
KW - Stress response
UR - http://www.scopus.com/inward/record.url?scp=0034303209&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034303209&partnerID=8YFLogxK
M3 - Article
VL - 14
SP - 447
EP - 450
JO - Shock
JF - Shock
SN - 1073-2322
IS - 4
ER -