PINK1-Parkin Pathway Activity Is Regulated by Degradation of PINK1 in the Mitochondrial Matrix
Bibliographic record
Abstract
Loss-of-function mutations in PINK1, which encodes a mitochondrially targeted serine/threonine kinase, result in an early-onset heritable form of Parkinson's disease. Previous work has shown that PINK1 is constitutively degraded in healthy cells, but selectively accumulates on the surface of depolarized mitochondria, thereby initiating their autophagic degradation. Although PINK1 is known to be a cleavage target of several mitochondrial proteases, whether these proteases account for the constitutive degradation of PINK1 in healthy mitochondria remains unclear. To explore the mechanism by which PINK1 is degraded, we performed a screen for mitochondrial proteases that influence PINK1 abundance in the fruit fly Drosophila melanogaster. We found that genetic perturbations targeting the matrix-localized protease Lon caused dramatic accumulation of processed PINK1 species in several mitochondrial compartments, including the matrix. Knockdown of Lon did not decrease mitochondrial membrane potential or trigger activation of the mitochondrial unfolded protein stress response (UPRmt), indicating that PINK1 accumulation in Lon-deficient animals is not a secondary consequence of mitochondrial depolarization or the UPRmt. Moreover, the influence of Lon on PINK1 abundance was highly specific, as Lon inactivation had little or no effect on the abundance of other mitochondrial proteins. Further studies indicated that the processed forms of PINK1 that accumulate upon Lon inactivation are capable of activating the PINK1-Parkin pathway in vivo. Our findings thus suggest that Lon plays an essential role in regulating the PINK1-Parkin pathway by promoting the degradation of PINK1 in the matrix of healthy mitochondria.
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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".