Characterizing chloride-dependent acidification in brain clathrin-coated vesicles
Bibliographic record
Abstract
Endocytic organelles maintain their acidic pH using the V-type ATPase proton pump. However, proton accumulation across the membrane generates a voltage and requires the movement of an additional ion, known as a counterion, to dissipate charge buildup. The role of counterion movement in endosomes is not clear, but a subpopulation of early endosomes, clathrin-coated vesicles (CCVs), has previously been shown to use external chloride (Cl−) to allow V-ATPase-dependent acidification. We aimed to determine the identity and function of this presumed Cl− transporting protein. Our sample of highly enriched bovine brain CCVs exhibited V-type ATPase-facilitated acidification in the presence of external Cl−, independent of the monovalent cations present. While unsuccessful at identifying the mechanism of anion transport, we used glutamate-facilitated acidification, density gradients, and mass spectrometry to show that most brain CCVs are synaptic vesicles, complementing results from earlier studies that argued similarity only on the basis on protein content. The source of Cl−-dependent acidification in brain CCVs may be vGLUT1, a synaptic vesicle glutamate transporter with known Cl− permeability, although CCVs in other tissues are likely to utilize different proteins to facilitate acidification.
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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 | 0.001 | 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) | 0.000 | 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 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".