The Ure2 αCap Is Required for GATA Factor Responses to Rapamycin, But Not Nitrogen Limitation
Bibliographic record
Abstract
Ure2 is a phosphoprotein and central negative regulator of nitrogen‐responsive Gln3 and Gat1 localization and their abilities to activate transcription. This negative regulation is achieved by forming Ure2‐Gln3 and Ure2‐Gat1 complexes which sequester these GATA factors in the cytoplasm of cells cultured in excess nitrogen. Ure2 itself is a dimer, the monomer of which consists of two core domains and a flexible protruding αcap. Here, we show that alterations in this αcap abolish rapamycin‐ (Rap‐) elicited nuclear Gln3 and, to a more limited extent, Gat1 localization but have little effect on the Gln3 and Gat1 responses to nitrogen limitation. Rap is a specific inhibitor of the global regulator, TorC1. Ure2 dephosphorylation is also stimulus‐specific, occurring after Rap treatment, but only minimally if at all in nitrogen‐limited cells. In contrast to Gln3, Rap‐elicited Ure2 dephosphorylation is independent of Sit4 and PP2A. Our data suggest that distinct regions of Ure2 are associated with the receipt and/or implementation of signals calling for cessation of GATA factor sequestration in the cytoplasm. This in turn is more consistent with the existence of distinct pathways for TorC1‐ and nitrogen limitation‐dependent control of GATA factor localization and function than it is with these stimuli representing sequential steps in a single regulatory pathway. Supported by: NIH GM‐35642–23, COCOF, FRFC 2.4547.11.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".