The Microtubule Plus-End Tracking Protein ARMADILLO-REPEAT KINESIN1 Promotes Microtubule Catastrophe in <i>Arabidopsis</i>
Bibliographic record
Abstract
Microtubule dynamics are critically important for plant cell development. Here, we show that Arabidopsis thaliana ARMADILLO-REPEAT KINESIN1 (ARK1) plays a key role in root hair tip growth by promoting microtubule catastrophe events. This destabilizing activity appears to maintain adequate free tubulin concentrations in order to permit rapid microtubule growth, which in turn is correlated with uniform tip growth. Microtubules in ark1-1 root hairs exhibited reduced catastrophe frequency and slower growth velocities, both of which were restored by low concentrations of the microtubule-destabilizing drug oryzalin. An ARK1-GFP (green fluorescent protein) fusion protein expressed under its endogenous promoter localized to growing microtubule plus ends and rescued the ark1-1 root hair phenotype. Transient overexpression of ARK1-RFP (red fluorescent protein) increased microtubule catastrophe frequency. ARK1-fusion protein constructs lacking the N-terminal motor domain still labeled microtubules, suggesting the existence of a second microtubule binding domain at the C terminus of ARK1. ARK1-GFP was broadly expressed in seedlings, but mutant phenotypes were restricted to root hairs, indicating that ARK1's function is redundant in cells other than those forming root hairs.
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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 | 0.001 | 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 | 0.001 | 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".