Mutations in the SAM Domain of the ETV6-NTRK3 Chimeric Tyrosine Kinase Block Polymerization and Transformation Activity
Bibliographic record
Abstract
The 12p13 ETV6 (TEL) gene is frequently targeted by chromosomal translocations in human malignancies, resulting in the formation of oncogenic ETV6 gene fusions. Many of the known partner genes encode protein tyrosine kinases (PTKs), generating fusion proteins that function as chimeric PTKs. ETV6-NTRK3 (EN), comprised of the ETV6 SAM domain fused to the NTRK3 PTK, is unique among ETV6 chimeric oncoproteins, as it is expressed in cancers of multiple lineages. We initially hypothesized that, similar to other ETV6-PTK chimeras, SAM-mediated dimerization of EN leads to constitutive activation of the PTK and downstream signaling cascades. However, when the EN SAM domain was replaced with an inducible FK506 binding protein (FKBP) dimerization system, resulting FKBP-NTRK3 chimeras failed to transform NIH 3T3 cells even though PTK activation was preserved. It was recently shown that the ETV6 SAM domain has two potential interacting surfaces, raising the possibility that this domain can mediate protein polymerization. We therefore mutated each EN SAM binding interface in a manner shown previously to abolish self-association of wild-type ETV6. Each mutation completely blocked the ability of EN to polymerize, to activate its PTK, and to transform NIH 3T3 cells. Furthermore, EN itself formed large polymeric structures within cells while mutant EN proteins were present only as monomers. Finally, we observed a dominant negative effect on the transformation of isolated SAM domains coexpressed in EN-transformed cells. Taken together, our results suggest that higher-order polymerization may be a critical requirement for the transformation activity of EN and possibly other ETV6-PTK fusion proteins.
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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".