Calcineurin Regulates Nuclear Factor I Dephosphorylation and Activity in Malignant Glioma Cell Lines
Bibliographic record
Abstract
Malignant gliomas (MG), including grades III and IV astrocytomas, are the most common adult brain tumors. These tumors are highly aggressive with a median survival of less than 2 years. Nuclear factor I (NFI) is a family of transcription factors that regulates the expression of glial genes in the developing brain. We have previously shown that regulation of the brain fatty acid-binding protein ( B-FABP ; FABP7 ) and glial fibrillary acidic protein ( GFAP ) genes in MG cells is dependent on the phosphorylation state of NFI, with hypophosphorylation of NFI correlating with GFAP and B-FABP expression. Importantly, NFI phosphorylation is dependent on phosphatase activity that is enriched in GFAP/B-FABP+ve cells. Using chromatin immunoprecipitation, we show that NFI occupies the GFAP and B-FABP promoters in NFI-hypophosphorylated GFAP/B-FABP+ve MG cells. NFI occupancy, NFI-dependent transcriptional activity, and NFI phosphorylation are all modulated by the serine/threonine phosphatase calcineurin. Importantly, a cleaved form of calcineurin, associated with increased phosphatase activity, is specifically expressed in NFI-hypophosphorylated GFAP/B-FABP+ve MG cells. Calcineurin in GFAP/B-FABP+ve MG cells localizes to the nucleus. In contrast, calcineurin is primarily found in the cytoplasm of GFAP/B-FABP-ve cells, suggesting a dual mechanism for calcineurin activation in MG. Finally, our results demonstrate that calcineurin expression is up-regulated in areas of high infiltration/migration in grade IV astrocytoma tumor tissue. Our data suggest a critical role for calcineurin in NFI transcriptional regulation and in the determination of MG infiltrative properties. Background: Nuclear factor I (NFI) phosphorylation controls the expression of glial genes associated with migration. Results: NFI is dephosphorylated and activated by a cleaved form of calcineurin in malignant glioma cells. Conclusion: NFI transcriptional activity in malignant glioma is regulated in part by calcineurin. Significance: Regulation of NFI by calcineurin provides a novel approach to control the expression of genes associated with migration/infiltration in malignant glioma.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".