Hsp72 and Stress Kinase c-jun N-Terminal Kinase Regulate the Bid-Dependent Pathway in Tumor Necrosis Factor-Induced Apoptosis
Bibliographic record
Abstract
The major inducible heat shock protein Hsp72 has been shown to protect cells from certain apoptotic stimuli. Here we investigated the mechanism of Hsp72-mediated protection from tumor necrosis factor (TNF)-induced apoptosis of primary culture of IMR90 human fibroblasts. Hsp72 temporarily blocked apoptosis in response to TNF and permanently protected cells from heat shock. An Hsp72 mutant (Hsp72 Delta EEVD) with a deletion of the four C-terminal amino acids, which are essential for the chaperone function, blocked TNF-induced apoptosis in a manner similar to that of normal Hsp72 but did not inhibit heat shock-induced death. Therefore, the chaperone activity of Hsp72 is dispensable for suppression of TNF-induced apoptosis but is required for protection from heat shock. In fibroblasts derived from Bid knockout mice, similar temporal inhibition of TNF-induced apoptosis was seen. In these cells neither normal Hsp72 nor Hsp72 Delta EEVD conferred additional protection from apoptosis, suggesting that Hsp72 specifically affects Bid-dependent but not Bid-independent apoptotic pathways. Furthermore, both normal Hsp72 and Delta Hsp72EEVD inhibited Bid activation and downstream events, including release of cytochrome c, activation of caspase 3, and cleavage of poly-ADP-ribose polymerase. Both Hsp72 and Delta Hsp72EEVD blocked activation of the stress kinase c-jun N-terminal kinase (JNK) by TNF, and specific inhibition of JNK similarly temporarily blocked Bid activation and the downstream apoptotic events. These data strongly suggest that in TNF-induced apoptosis, Hsp72 specifically interferes with the Bid-dependent apoptotic pathway via inhibition of JNK.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".