G Protein Preassembly Rescues Efficacy of W6.48 Toggle Mutations in Neuropeptide Y2 Receptor.

摘要: Ligand binding and pathway-specific activation of G protein–coupled receptors is currently being studied with great effort. Individual answers may depend on the nature ligands effector pathway. Recently, we have presented a detailed model neuropeptide Y bound to Y2R. Accordingly, C-terminal part peptide binds deeply in transmembrane bundle brings side chain most essential Y36 close proximity W6.48. Here, investigate role this interaction for ligand receptor. BRET sensors were used investigation coupling led identification preassembly Y2R-Gi complex. It further confirmed ligand-dependent recruitment arrestin3. Using equally sensitive readouts Gi arrestin as well quantification operational models agonism allowed us identify strong inherent bias over arrestin3 wild-type By systematic mutagenesis, found that W6.48 does not contribute affinity, but acts an allosteric connector couple recruitment. However, even mutagenesis small threonine did lead complete loss signaling. Interestingly, signaling was restored levels by contain naphthylalanine residue instead Y36. Steric polar contributions receptor are discussed context different mechanisms protein