Involvement of caspase-2 long isoform in Fas-mediated cell death of human leukemic cells
Bibliographic record
Abstract
Engagement of the plasma membrane receptor Fas can induce apoptosis of leukemic cells. Signaling through Fas requires the formation of a death-inducing signaling complex (DISC) that involves the cytoplasmic domain of Fas, the adaptor molecule FADD/MORT-1, and procaspase-8. The present study investigated whether another caspase, known as procaspase-2L, played a role in Fas-mediated cell death. A series of human leukemic variant cells was derived by stable transfection with a CASP2L antisense construct (CASP2L/AS). Specific down-regulation of procaspase-2L decreased the sensitivity of these cells to apoptosis induced by an agonistic anti-Fas antibody (Ab, clone CH11), as determined by studying DNA fragmentation, chromatin condensation, and externalization of phosphatidylserine on the plasma membrane. In leukemic cells transfected with an empty vector, anti-Fas Ab treatment activated caspase-8, decreased the expression of the BH3 domain-only protein Bid, triggered the release of cytochrome c from the mitochondria to the cytosol, and activated caspase-3. All these events could not be observed when CASP2L/AS cells were similarly treated with anti-Fas Abs. CASP2L/AS transfection did not inhibit the formation of the DISC and no direct interaction between procaspase-2L and either Fas or FADD or procaspase-8 was identified. Down-regulation of procaspase-2L inhibited anti-Fas Ab-mediated cleavage of c-FLIP (FLICE-inhibitory protein), a protein that interferes with the formation of a functional DISC. These results suggest that the long isoform of caspase-2 plays a role in the Fas-mediated pathway to cell death by contributing to caspase-8 activation at the DISC level.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".