Phospholamban domain IB forms an interaction site with the loop between transmembrane helices M6 and M7 of sarco(endo)plasmic reticulum Ca <sup>2+</sup> ATPases
Bibliographic record
Abstract
Transmembrane helix M6 of the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) has been shown to form a site of interaction with phospholamban (PLN). Site-directed mutagenesis was carried out in the cytoplasmic loop (L67) between M6 and M7 in SERCA1a to detect other SERCA-PLN binding sites. Mutants N810A, D813A, and R822A had diminished ability to interact functionally with PLN, but only D813A and R822A had reduced physical interaction with PLN. PLN mutants R25A, Q26A, N27A, L28A, Q29A, and N30A had enhanced physical interaction with wild-type (wt) SERCA1a, but physical interaction of these PLN mutants with SERCA1a mutants D813A and R822A was reduced about 2.5 fold (range 1.44-2.82). Exceptions were the interactions of PLN N27A and N30A with SERCA1a D813A, which were reduced by 7.3- and 5.8-fold, respectively. A superinhibitory PLN deletion mutant, PLNDelta21-29, had strong physical interactions with SERCA1a and with SERCA1a mutant D813A. Physical interactions with SERCA1a and mutant D813A were sharply diminished, however, for the PLN deletion mutant, PLNDelta21-30, lacking PLN N30. Physical interactions between SERCA1a and a PLN-cytochrome b(5) chimera containing PLN residues 1-29 were much stronger than those between a PLN-cytochrome b(5) chimera containing PLN residues 1-21 and lacking N27. These results suggest that a SERCA1-PLN interaction site occurs between L67 of SERCA1a and domain IB of PLN, which involves SERCA1a D813 and PLN N27 and N30.
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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 | 0.001 | 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 | 0.001 |
| 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".