Basal signaling activities of the wild-type hGPR83 and the deletion mutant hGPR83_del17-60.

A) NFAT-driven luciferase activity (IP3 formation); B) SRE-driven luciferase activity (ERK1/2-activity); C) SRF-driven luciferase activity (RhoA-activity), and D) cAMP accumulation basal and during forskolin stimulation. The forskolin/serotonin co-stimulated serotonin receptor (h5HTR1B) serves as Gi positive control. Data was assessed from a minimum of three independent experiments, each performed in triplicate, and calculated to the basal empty vector set to 1. Values represent mean + SEM. Significance was determined compared with an empty vector using one-way ANOVA and Dunnett´s test (A/B/C and D). Comparisons between wt and the deletion mutant were performed using the unpaired t-test, two-tailed (A and C). ***P ≤ 0.001, **P ≤ 0.01, *P ≤ 0.05 (one-way ANOVA, Dunnett´s test).