Homodimerization of CB ₂ cannabinoid receptor triggered by a bivalent ligand enhances cellular signaling

G protein-coupled receptors (GPCRs) exist within a landscape of interconvertible conformational states and in dynamic equilibrium between monomers and higher-order oligomers, both influenced by ligand binding. Here, we have shown that a homobivalent ligand formed by equal chromenopyrazole moieties as pharmacophores, connected by 14 methylene units, can modulate the dynamics of the cannabinoid CB ₂ receptor (CB ₂ R) homodimerization by simultaneously binding both protomers of the CB ₂ R-CB ₂ R homodimer. Computational and pharmacological experimentals showed that one of the ligand pharmacophores binds to the orthosteric site of one protomer, and the other pharmacophore to a membrane-oriented pocket between transmembranes 1 and 7 of the partner protomer. This provides unique pharmacological properties, such as increased potency in G _i binding and increased recruitment of β-arrestin. Thus, by modulating dimerization dynamics, it may be possible to fine-tune CB ₂ R activity with potentially improved therapeutic outcomes.