Myosin light chain phosphorylation facilitates in vivo myosin filament reassembly after mechanical perturbation
Bibliographic record
Abstract
Phosphorylation of the 20-kDa regulatory myosin light chain (MLC) of smooth muscle is known to cause monomeric myosins in solution to self-assemble into thick filaments. The role of MLC phosphorylation in thick filament formation in intact muscle, however, is not clear. It is not known whether the phosphorylation is necessary to initiate thick filament assembly in vivo. Here we show, by using a potent inhibitor of MLC kinase (wortmannin), that the MLC phosphorylation and isometric force in trachealis muscle could be abolished without affecting calcium transients. By measuring cross-sectional densities of the thick filaments electron microscopically, we also show that inhibition of MLC phosphorylation alone did not cause disassembly of the filaments. The unphosphorylated thick filaments, however, partially dissolved when the muscle was subjected to oscillatory strains (which caused a 25% decrease in the thick filament density). The postoscillation filament density recovered to the preoscillation level only when wortmannin was removed and the muscle was stimulated. The data suggest that in vivo thick filament reassembly after mechanical perturbation is facilitated by the cyclic MLC phosphorylation associated with repeated stimulation.
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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) | 0.001 | 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) | 0.000 | 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".