Investigating the Inhibitory Effects of Blebbistatin on Actomyosin Interactions in Myofibrils and Isolated Myofilaments
Bibliographic record
Abstract
Abstract Myosin II is the molecular motor responsible for muscle contraction. Myosin II hydrolyses ATP into P i and ADP, to convert chemical energy into mechanical work while attached to actin filaments. The relation between force generation and P i release remains unclear. Many studies use chemical substances, such as blebbistatin, to study the transitions during actomyosin interactions. Blebbistatin and its derivatives selectively inhibit the actin-activated ATPase of myosin II, accumulating myosin cross-bridges in a pre-power-stroke state. Although the effects of blebbistatin have been explored, it is still unclear how blebbistatin affects force generation and the velocity of contraction. In this study, we used individual myofibrils, myosin and actin filaments, and isolated heavy meromyosin (HMM) and actin filaments to characterize the effects of blebbistatin. We observed that increasing concentrations of blebbistatin (i) decreased the force produced by myofibrils and isolated myosin filaments, (ii) decreased the maximum velocity of shortening produced by myofibrils and the myosin-induced actin sliding velocity, (iii) decreased the curvature of the force-velocity relation in a dose-dependent manner. Furthermore, UV radiation reduced the effect of blebbistatin, which was partially reversed if blebbistatin was bound to myosin before exposure to UV light. These results show that blebbistatin alters force and velocity generation at the molecular, myofilamentous and myofibrillar levels. This study has interesting implications in fields which rely on using blebbistatin to study cellular processes and confirms several results published in different experimental arrangements. Thus, this study is exploratory and confirmatory, and the findings have utility surrounding cell migration, muscle biophysics, cellular reproduction, or any processes that rely on the action of myosin II.
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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 | 0.000 |
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 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".