The study shows how the weight‑loss peptide cagrilintide binds to two different receptors (amylin and calcitonin) in a similar way, using specific parts of the molecule to lock onto the receptors and turn on the same signaling pathway. This explains why the drug works on both targets and may help design better versions.

The global obesity epidemic and its associated metabolic disorders urgently require more effective therapeutic interventions, particularly multi-pathway targeting therapies. Cagrilintide (Cagri), functioning as a dual amylin receptor (AMYRs) and calcitonin receptor (CTR) agonist (DACRA), demonstrates significant efficacy in obesity treatment, although its structural activation mechanism remains unclear. This study elucidates the non-selective activation mechanism by determining cryo-EM structures of Cagri bound to AMY₁R-G_s and CTR-G_s complexes. Cagri adopts similar "bypass" binding modes in both receptors, which is distinct from other existing DACRAs that primarily achieve extended half-life through N-terminal lipid modification. Key molecular features include the F23^Cagri residue anchoring the peptide at the receptor transmembrane (TM) bundle level and the micelle, an E14-R17 intramolecular salt bridge enhancing helical stability, and C-terminal P37^Cagri interaction with the receptor ECD. These features collectively enable non-specific binding and activation across different receptors. Both structural and functional analyses revealed Cagri's non-selective activation of G_s signaling pathways through CTR and AMY₁R. These findings provide a comprehensive structural framework for developing next-generation anti-obesity drugs based on dual receptor activation mechanisms.