Oxytocin Induces Dephosphorylation of Eukaryotic Elongation Factor 2 in Human Myometrial Cells
Bibliographic record
Abstract
The oxytocin (OT) receptor (OTR) mediates a wide spectrum of biological actions and is expressed in a large number of different tissues, including uterine, breast, and lung tumors. To define more completely the intracellular signaling mechanisms linked to OTR activation, we have used a phosphoproteomics approach and have characterized changes in the phosphorylation states of intracellular proteins in response to OTR activation in OTR-expressing cell lines. Using a specific antiphosphothreonine antibody, we observed several distinct changes in the threonine phosphorylation patterns. The most prominent change involved dephosphorylation of a 95-kDa moiety. Purification by ion exchange chromatography combined with one- and two-dimensional polyacrylamide gel electrophoresis followed by N-terminal micro-sequence analysis revealed that the 95-kDa moiety corresponded to eukaryotic elongation factor 2. This protein is a key regulator of cellular protein synthesis and mediates, upon dephosphorylation, the translocation step of peptide chain elongation. Dose-response curves in myometrial cells expressing the endogenous OTR indicated a significant effect of OT on eukaryotic elongation factor 2 dephosphorylation at 1 nM, a concentration close to the dissociation constant (K(d)) of OT. Time course analysis indicates that the effect is rapid with a significant effect occurring at 5 min. To determine directly the effect of OT on protein synthesis, the incorporation of [35S]Met into total protein was assessed. In myometrial cells, OTR activation led to significant 29% increase in total protein synthesis over a 2-h period. These findings establish a novel link between OTR activation and cellular protein synthesis and thus define a mechanism by which OT assumes a so far unrecognized, physiologically relevant trophic 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 | 0.000 |
| 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".