Saturation ligand binding to membrane preparations of wild-type and TM6* cells producing human GPCRs. (A) Labelled and unlabelled ZM241385 ligands were incubated for 60 min at 25 °C with 10 μg cell membrane containing recombinant human A2aR. (B) Labelled and unlabelled CP55940 ligands were incubated for 90 min at 30 °C with 10 μg cell membrane containing recombinant human CNR2. Saturation binding curves were analysed by nonlinear regression using Prism Software (GraphPad Software, USA) to calculate Bmax and Kd. The immunoblot signals for the corresponding proteins are shown as insets within the binding curves.