Ammonium transport and pH regulation by K<sup>+</sup>-Cl<sup>-</sup>cotransporters
Bibliographic record
Abstract
The Na(+)-K(+)-Cl(-) cotransporters (NKCCs), which belong to the cation-Cl(-) cotransporter (CCC) family, are able to translocate NH4(+) across cell membranes. In this study, we have used the oocyte expression system to determine whether the K(+)-Cl(-) cotransporters (KCCs) can also transport NH4(+) and whether they play a role in pH regulation. Our results demonstrate that all of the CCCs examined (NKCC1, NKCC2, KCC1, KCC3, and KCC4) can promote NH4(+) translocation, presumably through binding of the ion at the K(+) site. Moreover, kinetic studies for both NKCCs and KCCs suggest that NH4(+) is an excellent surrogate of Rb(+) or K(+) and that NH4(+) transport and cellular acidification resulting from CCC activity are relevant physiologically. In this study, we have also found that CCCs are strongly and differentially affected by changes in intracellular pH (independently of intracellular [NH4(+)]). Indeed, NKCC2, KCC1, KCC2, and KCC3 are inhibited at intracellular pH <7.5, whereas KCC4 is activated. These results indicate that certain CCC isoforms may be specialized to operate in acidic environments. CCC-mediated NH4(+) transport could bear great physiological implication given the ubiquitous distribution of these carriers.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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".