Fig. 2

RCT001 is an inverse agonist of CXCR2. a-c The recombinant CXCR2 reconstituted in detergent buffer containing lipids that mimic the lipid composition of the receptor, is then labelled with a non-modifying probe that allow detection of the activation state and conformational change of the receptor upon addition of a ligand. The maximum wavelength of the probe emission spectrum (λmax) shifts according to the activation (TM6 opening)/inactivation (TM6 closing) of the receptor. The kinetics of receptor activation/inactivation can be followed by observing the λmax shift over time after addition of a ligand. a CXCR2 activation was measured by the λmax shift 20 min after stimulation by different doses of CXCL8. b CXCR2 activation was measured by the λmax shift 20 min after stimulation by a dose response of RCT001. c CXCR2 kinetic activation (0 to 30 min) was measured by the λmax shift after stimulation by CXCL8 (100 nM) or RCT001 (500 nM). d Starved endothelial cells were stimulated with 50 ng/ml CXCL8 for 1 h. Membrane-associated CXCR2 protein levels were quantified by flow cytometry. Results are presented as the mean of three independent experiments ± SD. Statistics were performed using the ANOVA test: *p < 0.05; **p < 0.01. e Summary schematic of the mechanism of action of RCT001 as an inverse CXCR2 agonist