Extended Data Fig. 4: Effects of mutations in the ligand-binding pocket of MRGPRX2 on C48/80 induced dissociation of G_αi–G_γ or G_αq–G_γ.

a, Key interactions between the ethylamine group of the C48/80 and W243^6.55, F170^ECL2, C168^4.64, C180^5.34, W248^6.60 of the MRGPRX2. The disulfide bond between the C168 and C180 was highlight in cyan. b, Key interactions between the amide of the ethylamine group of C48/80 and E164, D184 of MRGPRX2. Hydrogen bonds were showed in red dash. c, Important residues in MRGPRX2 that recognize the upper “Y” arm of C48/80. d, Elisa experiments to determine the expression levels of the MRGPRX2 wild type and corresponding mutants. Values are mean ± SEM from three independent experiments (n=3). n.s., no significance. All data were analysed by two-sided one-way ANOVA with Turkey test. e, Effects of mutations in the ligand-binding pocket residues of MRGPRX2 on C48/80–induced G_αi–G_γ dissociation in MRGPRX2 overexpressing HEK293 cells. Natural occurred SNPs were highlight in blue. ND, not detectable due to low signal. Values are the mean ± SEM of three independent experiments for the wild type (WT) and mutants (n=3). All data were determined by two-sided one-way ANOVA with Tukey test. *, P < 0.05; **, P < 0.01; ***, P < 0.001, n.s., no significant difference. (P =0.0028, 0.0001, 0.0171,  < 0.0001, 0.0045, ND,  < 0.0001,  < 0.0001, ND, 0.0224, 0.0178,  < 0.0001, 0.0050,  < 0.0001, 0.0008, 0.0007 from top to bottom.) f, Effects of mutations of key residues of MRGPRX2 on C48/80–induced G_αq–G_γ dissociation in MRGPRX2 overexpressing HEK293 cells. Values are the mean ± SEM of three independent experiments for the wild type (WT) and mutants (n=3) except E164A and D254A which are the mean ± SEM of five independent experiments (n=5). All data were determined by two-sided one-way ANOVA with Tukey test. ***, P < 0.001. (P < 0.0001,  < 0.0001,  < 0.0001,  < 0.0001,  < 0.0001,  < 0.0001 from top to bottom).