Bibliographic record
Abstract
Capacitation is broadly defined as the functional modifications rendering sperm competent to fertilize, encompassing the ability of the sperm to bind the zona pellucida and subsequently undergo the acrosome reaction, hyperactivated motility, and the capacity to fuse with the oocyte. Although discovered in 1951, research over the past 15 years has considerably clarified the mechanisms leading to capacitation. The purpose of this review is to discuss the challenges of studying capacitation and to summarize recent notions regarding its regulation. Of particular interest is an atypical soluble adenylyl cyclase that is stimulated by bicarbonate to activate protein kinase A and drive sperm protein tyrosine phosphorylation. The identities of the phosphorylated sperm-protein substrates and the kinase(s) responsible for their tyrosine phosphorylation have fostered major questions regarding this pathway. Recent investigations, however, have made exciting advances toward resolving these queries. Advanced proteomic approaches have revealed the tyrosine phosphorylated substrates to be implicated in a diverse range of cellular activities. SRC tyrosine kinase is a particularly interesting candidate as the mediator of the protein kinase A-driven sperm protein tyrosine phosphorylation. Future studies are merited to fully characterize additional signaling mediators such as phosphatases and other kinases that may be involved, to elucidate the functional importance of the tyrosine phosphorylation on those particular substrates and to appreciate the differences that may exist among species.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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".