Phosphatidic Acid and Phosphatidylserine Have Distinct Structural and Functional Interactions with the Nicotinic Acetylcholine Receptor
Bibliographic record
Abstract
Bilayers containing phosphatidylcholine (PC) and the anionic lipid phosphatidic acid (PA) are particularly effective at stabilizing the nicotinic acetylcholine receptor (nAChR) in a functional conformation that undergoes agonist-induced conformational change. The physical properties of PC membranes containing PA are also substantially altered upon incorporation of the nAChR. To test whether or not the negative charge of PA is responsible for this "bi-directional coupling," the nAChR was reconstituted into membranes composed of PC with varying levels of the net negatively charged lipid phosphatidylserine (PS). In contrast to PA, increasing levels of PS in PC membranes do not stabilize an increasing proportion of nAChRs in a functional resting conformation, nor do they slow nAChR peptide hydrogen exchange kinetics. Incorporation of the nAChR had little effect on the physical properties of the PC/PS membranes, as monitored by the gel-to-liquid crystal phase transition temperatures of the bilayers. These results show that a net negative charge alone is not sufficient to account for the unique interactions that occur between the nAChR and PC/PA membranes. Incorporation of the receptor into PC/PS membranes, however, did lead to an altered head group conformation of PS possibly by recruiting divalent cations to the membrane surface. The results show that the nAChR has complex and unique interactions with both PA and PS. The interactions between the nAChR and PS may be bridged by divalent cations, such as calcium.
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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 | 0.000 | 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) | 0.000 | 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".