Bioluminescence resonance energy transfer (BRET) assays for homodimer receptor identification and bimolecular fluorescence complementation and signaling in cells expressing A2A receptors in the presence of linear and cyclic Tat-like (disrupting) peptides 1 (linear TM5-Tat) and 2 (TM5-cyclic Tat-like). A scheme of BRET (A), molecular complementation (B) and cAMP determination (C) assays is shown close to each graph; AC = adenylyl cyclase. Panel A: data are mean +/− standard deviation (SD, n = 6 in duplicates). The blue arrow in the upper illustration denotes that, only if dimerization occurs, energy transfer from RLuc to coelenterazine H takes place, causing YFP excitation hence fluorescence emission. Panel B: data are mean +/− SD (n = 12 in duplicates); *** p < 0.001 respect to each control (analysis of variance (ANOVA) followed by Bonferroni’s post-hoc tests). Panel C: data are the mean (in % of increase over basal) +/- SD (n = 8 in duplicates). * p < 0.05 with respect to absence of peptides and no significant differences in linear versus cyclic by two-factor ANOVA analysis.