ODF1 Phosphorylation by Cdk5/p35 Enhances ODF1-OIP1 Interaction
Bibliographic record
Abstract
Cdk5 and p35 are integral components of the sperm tail outer dense fibers (ODFs), which contribute to the distinct morphology and function of the sperm tail. In this study, we sought to characterize and investigate the significance of Cdk5/p35 association with ODFs. We show that ODF2 interacts with Cdk5 and p35 but not with the Cdk5/p35 heterodimer. By using deletion mutants, the ODF2 binding region in p35 was mapped to residues 122 to 198. This overlaps the Cdk5 binding region in p35, explaining the inability of ODF2 to bind to the Cdk5/p35 complex. In vitro phosphorylation assay showed that although Cdk5/p35 does not phosphorylate ODF2, it phosphorylates ODF1. Mass spectrometry revealed that Cdk5/p35 specifically phosphorylates Ser193 in the ODF1 C-terminal region containing the Cys-X-Pro motif, the interaction site for the novel RING finger protein, ODF1 interacting protein (OIP1), a candidate E3 ubiquitin ligase, that also localizes in the sperm tail. Cdk5 phosphorylation of ODF1 Ser193 results in enhanced ODF1-OIP1 interaction. These findings suggest that Cdk5 may be important in promoting ODF1 degradation, and potentially, the detachment and fragmentation of the sperm tail following fertilization.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".