Table 1 Potency, efficacy, and affinity of the different MCP chemokines at the CCR2 receptor in β-arrestin recruitment, Fsk-stimulated cAMP inhibition, ERK phosphorylation, and radioligand-binding assays.

β-arr2 recruitment was assessed by BRET in Flp-In T-REx 293 cells transiently transfected with plasmids encoding CCR2-RLuc8 and β-arr2–YFP. Inhibition of cAMP was measured in c-Myc–FLAG–CCR2 Flp-In T-REx 293 cells transiently transfected with a plasmid encoding a BRET-based cAMP sensor. ERK1/2 phosphorylation was measured 3 min after c-Myc–FLAG–CCR2 Flp-In T-REx 293 cells were stimulated with chemokine. ¹²⁵I–MCP-1 competition binding was measured in membrane preparations of c-Myc–FLAG–CCR2 Flp-In T-REx 293 cells. pEC₅₀ and pK_i values are the negative log of EC₅₀ and inhibition constant (K_i) values, respectively, in molar units. E_max values are reported as a percentage of the value for MCP-1. Data are means ± SEM of three or four experiments, each performed in triplicate. *P < 0.05, **P < 0.01, ***P < 0.001 by one-way ANOVA with Dunnett’s multiple-comparison test. E_max is shown relative to that observed with MCP-1.