Fig. 3

Intracellular cAMP level in the HEK293 cells lysates overexpressing Gαi₃ with different Gβγ and for Gαi₃ muteins after stimulation of the D₂ receptor with full agonist (sumanirole). HEK293 cells transiently transfected with plasmids encoding different variants of the Gαi₃-Citrine, selected Gβ and Gγ subunits and D₂R-mCherry receptor were stimulated with sumanirole. The intracellular cAMP levels were determined in the cell lysates. Results are presented as a percentage of cAMP levels in control (stimulated nontransfected cells), as a mean ± 95% confidence interval (CI). Experiments were performed in duplicates n = 4, except for Gαi₃β₂γ₈ (n = 2) and Gαi₃β₂γ₁₀ (n = 1). An unpaired t-test was performed to evaluate differences between Gαi₃β₁γ₂ vs other Gβγ dimers as well as between wild type of Gαi₃ and muteins without lipidations in the presence of the Gβ₁γ₈ dimer (** – p < 0.01, *** – p < 0.005, **** – p < 0.001)