Role of protein tyrosine phosphorylation in the thapsigargin-induced intracellular Ca2+ store depletion during human sperm acrosome reaction
Bibliographic record
Abstract
During human sperm capacitation, an increase in phosphotyrosine content of specific proteins results partially from an increase in the intracellular free Ca(2+) concentrations. In the present study, the inter-regulation between protein phosphotyrosine content and the intracellular Ca(2+) concentration during the thapsigargin treatment of capacitated human sperm was investigated. The involvement of a tyrosine kinase pathway in the thapsigargin-induced acrosome reaction was also investigated. In response to thapsigargin, two sperm subpopulations, called LR (low responsive) and HR (high responsive), according to their increase in intracellular Ca(2+), were observed. In addition to their high increase in intracellular Ca(2+), sperm from the HR population expressed a higher protein phosphotyrosine content, and a higher proportion (P < 0.05) of them underwent the acrosome reaction in response to thapsigargin, as compared with LR sperm. Although the tyrosine kinase inhibitor PP2 abolished the thapsigargin-induced increase in protein phosphotyrosine content, it did not affect the intracellular Ca( 2+) concentration or the percentage of acrosome-reacted sperm. The inability of an src-related tyrosine kinase inhibitor to block the thapsigargin-mediated Ca(2+) increase and acrosomal exocytosis suggests that, during the acrosome reaction, the signalling pathway mediated by src-related tyrosine kinases is involved upstream of the capacitative Ca(2+) entry.
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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".