Fig. 3. Maximal Gαi mediated cAMP inhibition at CXCR3 is dependent on receptor endocytosis.

a Schematic representation of the cAMP sensor experimental design⁴⁰. Agonist dose-dependent inhibition of isoproterenol-induced cAMP production by the chemokines in HEK293 cells with concurrent transfection of b pcDNA 3.1 or c Dynamin K44A inhibits internalization as measured between 3- and 5-min following addition of 1 µM isoproterenol. d–f Kinetic data of 100 nM treated cells and g–i agonist dose-dependent of cAMP inhibition levels in HEK293 cells treated with CXCL9, CXCL10, and CXCL11, respectively. Data for g–i are measured between 3- and 5- min following addition of isoproterenol. Data for b–i are the mean ± SEM, n = 5 independent plate-based experiments. ns P ≥ 0.05, *P = 0.01–0.05, **P = 0.001–0.01, ***P = 0.0001–0.001, ****P < 0.0001 denotes statistically significant differences between E_max for dose–response data of pcDNA 3.1 versus Dynamin K44A transfection conditions at each ligand. Extra sum of squares F test was used for g–i. See Supplementary Fig. 2 for similar data on nuclear cAMP.