Figure S3.

Receptor Expression and G Protein Coupling in Orphan GPCR Cell Lines, Related to Figure 4

(A) Cell-surface expression of induced oGPCRs measured by ELISA. Data shown as mean ± SEM from n = 3-7 independent experiments performed in triplicate.

(B-D) Constitutive cAMP and IP₁ production (i.e., in the absence of ligand) upon orphan receptor induction provide insights into G protein-coupling. Data shown as mean ± SEM from n = 3-5 independent experiments, except for BRS3/BB₃ (n = 2 in (B) and (C)), GPR32 (n = 2 in (B)) and GPR3 (n = 2 in (C)).

(E) For three receptors, we discovered constitutive G protein-coupling unreported in Guide to Pharmacology or literature (Doi et al., 2016, Harding et al., 2018, Inoue et al., 2012, Martin et al., 2015, Muppidi et al., 2014, Pera et al., 2018, Suply et al., 2017), and for GPR15 robust G_i/o signaling in cAMP accumulation assays.