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 pKi values are the negative log of EC50 and inhibition constant (Ki) values, respectively, in molar units. Emax 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. Emax is shown relative to that observed with MCP-1.

β-Arrestin recruitmentcAMP inhibitionERK1/2 phosphorylation125I–MCP-1 binding
pEC50EmaxpEC50EmaxpEC50EmaxpKi
MCP-18.32 ± 0.06100 ± 29.10 ± 0.21100 ± 99.16 ± 0.24100 ± 1010.60 ± 0.08
MCP-27.24 ± 0.26*23 ± 3***7.34 ± 0.14***113 ± 97.58 ± 0.15***119 ± 98.88 ± 0.14***
MCP-37.33 ± 0.15*56 ± 4**8.47 ± 0.16*109 ± 98.09 ± 0.19***116 ± 109.50 ± 0.12***