The 26S proteasome binds and degrades Pih1 via the C‐terminal degron elements in yeast <i>Saccharomyces cerevisiae</i>
Bibliographic record
Abstract
In yeast Saccharomyces cerevisiae , R2TP complex is required for the box C/D small nucleolar ribonucleoprotein (snoRNP) assembly and ribosomal RNA processing. This complex is composed of Rvb1 and Rvb2, two ATP‐dependent DNA helicases, Tah1, an Hsp90 cofactor, and Pih1, a subunit that acts as a scaffold and likely regulates the Rvb1/Rvb2 helicase activities. We have previously shown that Rvb1 and Rvb2 bind to the N‐terminal fragment of Pih1, while Tah1 binds to the Pih1 C‐terminal fragment. Additionally, the C‐terminus of Pih1 acts as a degron that regulates Pih1 degradation in vivo and controls R2TP complex assembly. To understand the mechanism of Pih1 degradation in vivo, we purified Pih1 protein complex from yeast cells and immunoblotting analysis indicated that Pih1 is able to pull down some 26S proteasome subunits. In vitro binding assays indicated that Pih1 C‐terminal degron elements are likely to interact with 26S proteasome directly. Based on in vitro and in vivo degradation assay, we propose a model of proteasome dependent, but ubiquitin independent degradation of Pih1 in yeast cells. (This work is supported by a Connaught New Staff Matching Fund and an NSERC Discovery Grant to RZ)
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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 | 0.001 |
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".