Ca <sup>2+</sup> -induced movement of tropomyosin on native cardiac thin filaments revealed by cryoelectron microscopy
Bibliographic record
Abstract
Significance Muscle contraction is required for critical physiological functions. It relies on the interaction of myosin motors with the thin filament (TF), which is regulated through a translocation of tropomyosin on the surface of F-actin by the troponin complex in response to Ca 2+ . The lack of high-resolution structure of the TF under relaxing (low-Ca 2+ ) and activating (high-Ca 2+ ) conditions impairs our understanding of the mechanism of cardiac muscle regulation. Here we report high-resolution structures of the native cardiac TF under relaxing and activating conditions. Our data lead to a model for cardiac TF regulation by Ca 2+ levels that is an important step in understanding how the components of cardiac muscle work in concert to maintain healthy heart functions.
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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 | 0.001 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".