Dynein-Driven Mitotic Spindle Positioning Restricted to Anaphase by She1p Inhibition of Dynactin Recruitment
Bibliographic record
Abstract
Dynein is a minus-end-directed microtubule motor important for mitotic spindle positioning. In budding yeast, dynein activity is restricted to anaphase when the nucleus enters the bud neck, yet the nature of the underlying regulatory mechanism is not known. Here, the microtubule-associated protein She1p is identified as a novel regulator of dynein activity. In she1 Delta cells, dynein is activated throughout the cell cycle, resulting in aberrant spindle movements that misposition the spindle. We also found that dynactin, a cofactor essential for dynein motor function, is a dynamic complex whose recruitment to astral microtubules (aMTs) increases dramatically during anaphase. Interestingly, loss of She1p eliminates the cell-cycle regulation of dynactin recruitment and permits enhanced dynactin accumulation on aMTs throughout the cell cycle. Furthermore, localization of the dynactin complex to aMTs requires dynein, suggesting that dynactin is recruited to aMTs via interaction with dynein and not the microtubule itself. Lastly, we present evidence supporting the existence of an incomplete dynactin subcomplex localized at the SPB, and a complete complex that is loaded onto aMTs from the cytoplasm. We propose that She1p restricts dynein-dependent spindle positioning to anaphase by inhibiting the association of dynein with the complete dynactin complex.
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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".