Fig. 6.

S-4-CMTB is more potent than R-4-CMTB at hFFA2-eYFP. A, racemic 4-CMTB and individual stereoisomers were examined for their ability to promote [³⁵S]GTPγS incorporation. R-4-CMTB was significantly less potent and efficacious than both racemic 4-CMTB and S-4-CMTB, according to one-way ANOVA with Dunnett's post hoc analysis. *, p < 0.05; **, p < 0.01. B, 4-CMTB stereoisomers are not active at the closely related hFFA3-eYFP. C, R-4-CMTB and S-4-CMTB are not additive when coincubated, suggesting binding to the same site on hFFA2-eYFP. D, only the S-isomer of the structurally related ligand HWD020 is able to activate hFFA2-eYFP. Inset, R-HWD020 is unable to inhibit signaling in response to 30 μM S-HWD020. Data are mean ± S.E.M (n = 3) for all panels.