Roles and regulation of «Saccharomyces cerevisiae» Rho-type GTPases Rho5p and Cdc42p
Bibliographic record
Abstract
The eukaryotic Rho family of GTPases acts as central regulators of numerous processes, including the polarization of cell morphology, membrane transport, transcription, and MAPK pathway signaling. As GTPases, Rho proteins act as molecular switches which, in the GTP-bound form, transduce upstream signals to a variety of downstream effectors, thereby generating appropriate cellular responses. As central nodes of signaling, they are subject to strict regulation, and the regulation of the GTP-GDP cycle of Rho members has been well characterized. Rho GTPases participate in a variety of pathways, though in many cases the mechanisms are still poorly understood. This study examines the roles and regulation of two Rho GTPases in Saccharomyces cerevisiae, Rho5p and Cdc42p. First, we describe the regulation of Rho5p signaling by phosphorylation and ubiquitination, the first instance of post-translational regulation of a yeast Rho-type GTPase. This regulation is mediated by a module involving the Npr1p kinase and its inhibitor Msi1p. We also identify Rgd2p as the RhoGAP for Rho5p in vivo, and demonstrate a genetic interaction between RHO5 and STE50: a STE50 deletion combined with expression of an activated RHO5 allele results in osmotic sensitivity. Next, we describe a role for Rho5p in the activation of the cAMP-PKA pathway. Expression of an activated allele of RHO5 generates a number of phenotypes associated with activated cAMP-PKA pathway signaling, and also suppresses the lethality of a strain deleted for two other cAMP-PKA activators, Δras1 Δras2. A mechanism by which Rho5p may activate the pathway is suggested by the observed two-hybrid interaction between Rho5p and adeny
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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 | 0.001 | 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 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".