Structure/Function Studies of the Gamma Subunit of the Na,K‐ATPase
Bibliographic record
Abstract
The Na,K-ATPase gamma subunit is present primarily in kidney as two splice variants, gammaa and gammab, which differ only at their extracellular N-termini. Two distinct effects of gamma are seen in biochemical Na,K-ATPase assays of mammalian (HeLa) cells transfected with gammaa or gammab, namely, (i) a decrease in K'(ATP) probably secondary to a shift in steady-state E(1) <--> E(2) poise in favor of E(1) and (ii) an increase in cytoplasmic K(+)/Na(+) antagonism seen as an increase in K'(Na) at high K(+) concentration. Mutagenesis experiments involving alterations in extramembranous regions of gamma indicate that different regions mediate the aforementioned distinct effects and that the effects appear to be long range. Studies of ouabain-sensitive fluxes with intact cells confirm the gamma effects seen with membranes and also suggest an additional effect (increase) in apparent affinity for extracellular K(+). Alteration in gamma function was also evidenced in the behavior of a G41 -->R mutation within the transmembrane domain of gamma. G41R is associated with autosomal dominant renal magnesium wasting. Our studies show that this mutation in the gammab variant retards trafficking of gamma, but not alphabeta pumps, to the cell surface and abolishes functional effects of gamma, consistent with the conclusion that the Mg(2+) transport defect is secondary to loss of gamma modulation of Na,K-ATPase function.
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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 | 0.001 |
| 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".