Fig. 3: G protein activation by FZDs and SMO.

a Schematic presentation of G_i1/s sensor design and assay principle. b G_i1 activation by FZD₆ and SMO wild-type and mutants. c G_s activation by FZD₇. Empty vector (pcDNA) transfection was employed as a negative control and the histamine H₃ receptor (b) and β₂AR stimulated with 10 µM isoprenaline (c) were used as positive controls. Data are represented as mean ± SEM of three independent experiments measured in octuplicates. Statistical difference was assessed using One-Way ANOVA followed by Sidak’s multiple comparison. *P < 0.05; ****P < 0.0001; ns not significant. All experiments were conducted in HEK293A cells transiently co-transfected with the indicated G protein sensor and receptor. See Supplementary Fig. 6e for the cell-surface expression of the utilized FZD₆, FZD₇, and SMO constructs. Source data are provided as a Source Data file.