A novel bioassay for detecting GPCR heterodimerization: transactivation of beta 2 adrenergic receptor by bradykinin receptor.

Many G-protein-coupled receptors (GPCRs) have been shown to form heteromeric complexes primarily by biochemical methods, including competitive radioligand binding assays or measurements of changes in second-messenger concentration in lysed cells. These results are often cell line specific, and the expression of other cell surface proteins makes it difficult to detect potential functional consequences of GPCR interaction. Here, 2-electrode voltage clamping in Xenopus oocytes was used as a bioassay to explore heterodimerization of bradykinin type 2 receptor (Bk2R) and beta 2 adrenergic receptor (beta(2)AR), using chloride channels as outputs for receptor activation.