Fig. 1
From: Quaternary structure of a G-protein-coupled receptor heterotetramer in complex with Gi and Gs
Cell surface mobility of A1R-GFP and A2AR-mCherry. Individual trajectories of particles containing GFP fused to the C-terminus of A1R (A1-GFP) (a and b) or mCherry fused to the C-terminus of A2AR (A2A-mCherry) (d and e) on HEK-293T cells expressing A1-GFP (a), A2A-mCherry (d) or both (b and e). The trajectory and the fluorescence intensity of the individual particles were recorded over time using total internal reflection microscopy (TIRFM) and an electron multiplying charged-coupled device (EMCCD) camera recording. Receptor motion was determined by plotting (versus time lag) the mean square displacement (MSD) of A1-GFP (c) in the absence (black line) or presence of A2A-mCherry (blue line), or A2A-mCherry (f) in the presence (black line) or presence of A1-GFP (blue line). Data sets were fitted to mathematical models of free and confined diffusion for A1R and A2AR respectively. g Co-localization of A1-GFP and A2A-mCherry is observed (yellow dots). Scale bar: 100 nm. h Distribution of the fluorescence signal of A1-GFP (left) and A2A-mCherry (right) within co-localized receptors (yellow dots in g). Curves approximately delineate the number of monomers, dimers, or trimers within the co-localized complex. i Stoichiometry analysis performed for co-localized A1-GFP and A2A-mCherry receptor particles co-expressed in HEK-293T cells (yellow dots in g). Green corresponds to A1-GFP and red to A2A-mCherry