Cab39 modulates SPAK/OSR1 activation of NKCC1
Bibliographic record
Abstract
Calcium binding protein 39 (Cab39) is a scaffolding protein that stabilizes a heterotrimeric protein complex that modulates the activity of the adenosine mono‐phosphate kinase which regulates cellular energy homeostasis. Cab39 also modulates SPAK (Ste20 related Proline Alanine rich Kinase) and OSR1 (Oxidative stress responsive kinase 1), two kinases involved in activating the Na‐K‐2Cl cotransporter‐1 (NKCC1). In this study, we demonstrate that mouse Cab39 can substitute for WNK4 phosphorylation of a key serine residue (S383) in the SPAK‐T243E mutant, and even substitute for WNK4 phosphorylation of another key activating residue (threonine 243) when two wild‐type SPAK molecules are tethered together. Western blot analysis of frog oocyte lysates shows an intense signal for an endogenous Cab39. This observation raises the question of why the mouse isoform is necessary to observe the Cab39 effect on SPAK/OSR1 activation of NKCC1. To address this problem, we cloned the cDNA encoding the Xenopus Cab39 isoform and tested its effect on SPAK/OSR1 activation of NKCC1 in frog oocytes. Using site‐directed mutagenesis, we further examined residues that might be involved in the Cab39‐SPAK‐NKCC1 regulatory pathway.
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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) | 0.002 | 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".