Figure 6.

cAMP signaling properties of AM and CGRP agonist variants with enhanced ECD affinities. (A,B) Concentration–response cAMP accumulation assays in COS-7 cells transiently expressing the indicated receptors with the indicated (A) AM or (B) CGRP peptides. (C,D) Sustained cAMP signaling after ligand washout assays using 100 nM of the indicated (C) AM or (D) CGRP peptides at the indicated receptors transiently expressed in COS-7 cells. (E,F) Concentration–response cAMP accumulation assays for the indicated AM and CGRP peptides in (E) primary HUVECs or (F) SK-N-MC cells. (G,H) Sustained cAMP signaling after ligand washout assays with 100 nM of the indicated AM and CGRP peptides in (G) primary HUVECs or (H) SK-N-MC cells. Representative accumulation assays from three independent replicates performed on different days are shown, whereas the washout assays are presented as a normalized composite of three independent experiments. See Table S6 for the pEC₅₀ values with SEM from the accumulation assays and associated statistical analyses.