A transcytotic actin shift polarizes vesicle trajectories and partitions apicobasal epithelial membrane domains
Bibliographic record
Abstract
Abstract In prevailing epithelial polarity models, membrane-based polarity cues such as the partitioning-defective PARs specify the positions and identities of apicobasal membrane domains. Recent findings suggest, however, that vesicle-associated polarity cues specify membrane polarity by positioning the apical domain, upstream of membrane-based polarity cues. These findings raised the question how vesicles acquire apicobasal directionality independent of polarized target membrane domains. Here, we show that the apical directionality of vesicle trajectories depends on intracellular actin dynamics during the establishment of membrane polarity in the C. elegans intestine. We find that actin, powered by branched-chain actin dynamics, determines the position of apical membrane components, PARs, and itself on expanding membranes. Using photomodulation, we demonstrate that F-actin travels through the cytoplasm and along the cortex towards the future apical domain. Our findings suggest an alternative polarity model where actin-dependent directional trafficking inserts the nascent apical domain into the growing membrane to partition its apicobasal domains.
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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".