Fig. 2.

Bivalent ligands with 20- and 30-Å distance induce receptor dimerization. (A) Dimerization was measured using HEK293 cells coexpressing an NLuc- and Cherry-tagged GRPR. (B and C) Monovalent agonists and antagonists were not able to induce receptor dimerization. (D–F) Bivalent agonists, antagonists, and hybrid compounds with 20- and 30-Å distance between ligands induced dimerization, whereas bivalent compounds with 10-Å distance failed to induce dimerization. The curves represent time-resolved measurements of one representative experiment out of three (mean ± SEM of triplicate). The orange dotted line indicates the time point of the ligand addition. Control (Ctrl): no ligand addition.