Role of the GRK2 extreme amino terminus and active site tether in forming G protein‐coupled receptor docking site
Bibliographic record
Abstract
G protein‐coupled receptor (GPCR) kinases (GRKs) phosphorylate agonist‐activated GPCRs to initiate receptor desensitization, but the mechanism of kinase domain activation is unclear. Because agonist‐activated receptors dramatically stimulate the catalytic activity of GRKs, we sought to identify GRK2 residues located outside the active site that play a role in receptor interaction. Previous work suggested that active site tether (AST) residues of the kinase carboxyl‐tail extension are required for GRK activation, and that N‐terminal helix and AST interaction is important for receptor phosphorylation. We therefore carried out systematic mutagenesis of residues 3–18 and the AST of GRK2, and characterized these mutants using in vitro rhodopsin and peptide phosphorylation, GRK activation, intact cell β 2 ‐adrenergic receptor phosphorylation, and cell based α 2 ‐adrenergic receptor recruitment assays. Our results suggest that the N‐terminus and AST, both intrinsically disordered in the inactive kinase, play important roles in formation of the interaction site with activated receptors. Funding: NSF (RSM), NIH (JT), Canadian Institute for Health Research (MB), and FRSQ & Groupe de Recherche Universitaire sur le Médicament (AB).
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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 | 0.001 |
| 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".