The Na/monocarboxylate cotransporter SMCT1 displays an invariant 2:1 cotransport stoichiometry
Bibliographic record
Abstract
SMCT1 is encoded by the SLC5A8 gene, which is inactivated by methylation in colon, brain and thyroid cancer. SMCT1 cotransports Na + with different monocarboxylates containing 3 to 8 carbon atoms but the transport properties discovered so far are insufficient to explain the putative role played by SMCT1 in cell proliferation. Three different stoichioimetries have been published for the cotransport passing through SMCT1, including a claim for different stoichiometries when lactate and propionate are cotransported. Electrophysiological analysis of this cotransporter is impeded by the presence of an anionic leak with the following selectivity (NO 3 − > I − >Br − >Cl − ). We have established a 2:1 stoichiometry for lactate cotransport by use of three independent techniques: one method combined radiolabel uptake with current measurements, another combined radiolabel uptake with volume measurements and a third compared membrane potential changes in response to altered external substrate concentrations. We showed that the first two methods are unsuitable for measuring stoichiometry of propionate, which diffuses readily across the membrane. The third method is unaffected by passive diffusion of propionate and established a constant, 2:1 stoichiometry through this protein for both lactate and propionate. Volume measurement during the stimulation of a NO 3 − leak indicates a simple influx of inorganic anions which appears unaffected by the presence of substrate. In conclusion, SMCT1 exhibits a 2:1 stoichiometry which coexists with an anionic leak current.
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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 | 0.001 | 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".