Caloxin: a novel plasma membrane Ca<sup>2+</sup>pump inhibitor
Bibliographic record
Abstract
Plasma membrane (PM) Ca2+ pump is a Ca+-Mg2+-ATPase that expels Ca2+ from cells to help them maintain low concentrations of cytosolic Ca2+ . There are no known extracellularly acting PM Ca2+ pump inhibitors, as digoxin and ouabain are for Na+ pump. In analogy with digoxin, we define caloxins as extracellular PM Ca2+ pump inhibitors and describe caloxin 2A1. Caloxin 2A1 is a peptide obtained by screening a random peptide phage display library for binding to the second extracellular domain (residues 401-413) sequence of PM Ca2+ pump isoform 1b. Caloxin 2A1 inhibits Ca2+-Mg2+-ATPase in human erythrocyte leaky ghosts, but it does not affect basal Mg2+-ATPase or Na+-K+-ATPase in the ghosts or Ca2+-Mg2+-ATPase in the skeletal muscle sarcoplasmic reticulum. Caloxin 2A1 also inhibits Ca2+-dependent formation of the 140-kDa acid-stable acylphosphate, which is a partial reaction of this enzyme. Consistent with inhibition of the PM Ca2+ pump in vascular endothelium, caloxin 2A1 produces an endothelium-dependent relaxation that is reversed by N(G)-nitro-L-arginine methyl ester. Thus caloxin 2A1 is a novel PM Ca2+ pump inhibitor selected for binding to an extracellular domain.
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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) | 0.001 | 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 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".