The solute carrier 44A1 is a mitochondrial protein and mediates choline transport
Bibliographic record
Abstract
Choline oxidation to betaine takes place in the mitochondria; however, a protein regulating mitochondrial choline transport was never identified. The purpose of this study was to analyze subcellular localization of the solute carrier 44A1 (SLC44A1), a plasma membrane choline transporter sensitive to inhibition by hemicholinium-3. We generated N- and C-terminal-SLC44A1-specific antibodies and analyzed localization of endogenous and overexpressed SLC44A1 in C2C12 mouse muscle cells, MCF7 human breast cancer cells, and mouse tissues using confocal microscopy, differential centrifugation, and Western blotting. We further performed choline uptake competition studies on isolated mitochondria using the specific inhibitor hemicholinium-3 and SLC44A1 antibodies, and analyzed mitochondria of FL83B hepatocytes after the targeted knock-down of SLC44A1 using siRNA technology. In addition, we analyzed SLC44A1 expression during choline deficiency. Localization studies revealed plasma membrane, cytosolic, microsomal, and mitochondrial localization of endogenous and His-tagged SLC44A1. Uptake studies in isolated mitochondria show an accumulation of (3)H-choline, which is strongly inhibited by hemicholinium-3 (60%), by an excess of unlabeled choline (97%), and by both SLC44A1 antibodies. SLC44A1 mRNA and protein expression were down-regulated during choline deficiency. These data clearly establish SLC44A1 as an important mediator of choline transport across both the plasma membrane and the mitochondrial membrane.
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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) | 0.000 | 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) | 0.000 | 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".