Mitochondrial protein import and assembly dynamics in response to chronic contractile activity in skeletal muscle of young and aged animals
Bibliographic record
Abstract
Mitochondrial protein import adapts to perturbations in cellular energy status by altering the rate at which nuclear‐encoded proteins are translocated into mitochondria. The purposes of this study were to determine whether the import and assembly of precursor proteins are similar in muscle from young and aged F344XBN animals, and to assess the effect of chronic contractile activity (CCA) on the import pathway in subsarcolemmal (SS) mitochondria. Import of Tom40 into the outer membrane increased (p<0.05) over time in both young and aged animals, but was not different between the two groups. However, assembly of the multisubunit TOM complex containing Tom40, as assessed by Blue Native‐PAGE, was 2.2‐fold greater (p<0.05) in aged, when compared to young animals. Following 7 days of CCA (3hr/day), Tom40 assembly into the TOM complex was accelerated by 75%, compared to non‐stimulated muscle in young animals. This increase due to CCA was only 65% in aged animals (p<0.05). CCA also resulted in an 85% increase in the import of the matrix protein OCT in SS mitochondria from young animals, while only a 28% increase in OCT import was observed in aged animals (p<0.05). Our findings suggest that aged muscle has a greater capacity to assemble Tom40 into a functional TOM complex, when compared to young animals. CCA can further accelerate the rate of import and assembly in both groups, however this effect is attenuated with age.
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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".