Solution NMR and calorimetric analysis of Rem2 binding to the Ca <sup>2+</sup> channel β4 subunit: a low affinity interaction is required for inhibition of Cav2.1 Ca <sup>2+</sup> currents
Bibliographic record
Abstract
ABSTRACT Rem, Rad, Kir/Gem (RGK) proteins, including Rem2, mediate profound inhibition of high‐voltage activated Ca 2+ channels containing intracellular regulatory β subunits. All RGK proteins bind to voltage‐gated Ca 2+ channel β subunit (Cavβ) subunits in vitro , but the necessity of the interaction for current inhibition remains controversial. This study applies NMR and calorimetric techniques to map the binding site for Rem2 on human Cavβ4a and measure its binding affinity. Our experiments revealed 2 binding surfaces on the β4 guanylate kinase domain contributing to a 156 ± 18 μM K d interaction: a hydrophobic pocket lined by 4 critical residues (L173, N261, H262, and V303), mutation of any of which completely disrupted binding, and a nearby surface containing 3 residues (D206, L209, and D258) that when individually mutated decreased affinity. Voltage‐gated Ca 2+ channel α1A subunit (Cav2.1) Ca 2+ currents were completely inhibited by Rem2 when co‐expressed with wild‐type Cavβ4a, but were unaffected by Rem2 when coexpressed with a Cavβ4a site 1 (L173A/V303A) or site 2 (D258A) mutant. These results provide direct evidence for a low‐affinity Rem2/Cavβ4 interaction and show definitively that the interaction is required for Cav2.1 inhibition.—Xu, X., Zhang, F., Zamponi, G. W., Horne, W. A. Solution NMR and calorimetric analysis of Rem2 binding to the Ca 2+ channel β4 subunit: a low affinity interaction is required for inhibition of Cav2.1 Ca 2+ currents. FASEB J. 29, 1794‐1804 (2015). www.fasebj.org
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| 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".