Nucleotide-dependent binding of the GTPase domain of the signal recognition particle receptor beta subunit to the alpha subunit
Bibliographic record
Abstract
The signal recognition particle (SRP) receptor (SR) is a heterodimer of two polypeptides (SRα and SRβ) that each contain a GTP-binding domain. The GTP-binding domain in the peripheral membrane SRα subunit has a well defined role in regulating targeting of SRP-ribosome-nascent chain complexes to the translocon. The only well established function for the transmembrane SRβ subunit is anchoring SRα on the endoplasmic reticulum membrane. Deletion of the amino-terminal transmembrane domain of SRβ did not affect receptor dimerization, but revealed a cryptic translocation signal that overlaps the GTPase domain. We demonstrate that the domain of SRα that binds SRβ does so by binding directly to the nucleotide-bound form of the GTPase domain of SRβ. An SRβ mutant containing an amino acid substitution that allows the GTPase domain to bind XTP dimerized with SRα most efficiently in the presence of XTP or XDP, but not ATP. Our results suggest an additional level of regulation of SRP receptor function based on regulated dissociation of the receptor subunits.
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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".