Characterization of the GbpD-activated Rap1 Pathway Regulating Adhesion and Cell Polarity in Dictyostelium discoideum
Bibliographic record
Abstract
The regulation of cell polarity plays an important role in chemotaxis. GbpD, a putative nucleotide exchange factor for small G-proteins of the Ras family, has been implicated in adhesion, cell polarity, and chemotaxis in Dictyostelium. Cells overexpressing GbpD are flat, exhibit strongly increased cell-substrate attachment, and extend many bifurcated and lateral pseudopodia. These cells overexpressing GbpD are severely impaired in chemotaxis, most likely due to the induction of many protrusions rather than an enhanced adhesion. The GbpD-overexpression phenotype is similar to that of cells overexpressing Rap1. Here we demonstrate that GbpD activates Rap1 both in vivo and in vitro but not any of the five other characterized Ras proteins. In a screen for Rap1 effectors, we overexpressed GbpD in several mutants defective in adhesion or cell polarity and identified Phg2 as Rap1 effector necessary for adhesion, but not cell polarity. Phg2, a serine/threonine-specific kinase, directly interacts with Rap1 via its Ras association domain.
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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".