Role of JNK in hypertonic activation of Cl<sup>−</sup>-dependent Na<sup>+</sup>/H<sup>+</sup> exchange in <i>Xenopus </i>oocytes
Bibliographic record
Abstract
In the course of studying the hypertonicity-activated ion transporters in Xenopus oocytes, we found that activation of endogenous oocyte Na(+)/H(+) exchange activity (xoNHE) by hypertonic shrinkage required Cl(-), with an EC(50) for bath [Cl(-)] of approximately 3mM. This requirement for chloride was not supported by several nonhalide anions and was not shared by xoNHE activated by acid loading. Hypertonicity-activated xoNHE exhibited an unusual rank order of inhibitory potency among amiloride derivatives and was blocked by Cl(-) transport inhibitors. Chelation of intracellular Ca(2+) by injection of EGTA blocked hypertonic activation of xoNHE, although many inhibitors of Ca(2+)-related signaling pathways were without inhibitory effect. Hypertonicity activated oocyte extracellular signal-regulated kinase 1/2 (ERK1/2), but inhibitors of neither ERK1/2 nor p38 prevented hypertonic activation of xoNHE. However, hypertonicity also stimulated a Cl(-)-dependent increase in c-Jun NH(2)-terminal kinase (JNK) activity. Inhibition of JNK activity prevented hypertonic activation of xoNHE but not activation by acid loading. We conclude that hypertonic activation of Na(+)/H(+) exchange in Xenopus oocytes requires Cl(-) and is mediated by activation of JNK.
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 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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".