Cloning, expression, and localization of a rat hepatocyte inwardly rectifying potassium channel
Bibliographic record
Abstract
Bile formation involves anion accumulation within the apical lumen of hepatocytes. Potassium flux through hepatocellular basolateral membrane channels may provide the counterion for apical anion efflux. Here we cloned a molecular candidate for maintaining charge balance during bile secretion. Two transcripts resembling the Kir4.2 subclass of inwardly rectifying potassium channels were found. The longer deduced isoform (4.2a) has 30 additional NH(3)-terminal amino acids, which identifies this as a new isoform. The short-form isoform shared 86-91% identity with the mouse, human, and guinea pig channels. Whole cell currents of either rat isoform expressed in HEK293T cells demonstrated time independence and inward rectification. Antibodies against a COOH-terminal fragment recognized bands between 40 and 45 kDa and at 90 kDa and recognized a high molecular mass band around 200 kDa in overexpressing HEK cells. Immunohistology of liver tissue shows hepatocellular plasma membrane localization. In hepatocyte couplets, Kir4.2 was predominantly localized to the basolateral membrane. Results demonstrate expression of a new Kir4.2 isoform in the rat hepatocyte whose functional properties are compatible with a role in maintaining electrical integrity of bile-generating hepatocytes.
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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 | 0.001 |
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".