Figure 2.

Transfer of the G_q-binding site to G_s results in complete inhibition by FR900359. Mutant G_q and G_s proteins were expressed in ΔG_q/11-HEK293 and ΔG_s-HEK293 cells, respectively, to enable assessment of their potential inhibition by FR900359. After treatment with FR900359, the cells were stimulated with either carbachol (15 μm) or isoproterenol (5 nm), activating the endogenous G_q-coupled muscarinic acetylcholine receptor M3 or the endogenous G_s-coupled β₂-adrenergic receptor, respectively. A and B, normalized concentration-inhibition curves of FR900359 on WT G_q and derived G_q mutants. C, -fold change in FR900359 potency for G_q mutants compared with WT. D, normalized concentration-inhibition curves of FR900359 on WT G_s and the G_s-11 mutant (V57I, F68Y, E73D, T76G, K77F, D80L, L189P, S191T, F194I, T196Y, K197P). A, B, and D, each data point represents the mean value for that data point across experiments (n = 3–5). Error bars, S.E. C, each data point represents an independent experiment (n = 3–10), and the bars show the corresponding mean.