Figure 4. Generalization of Gαi-coupled GPCR target specificity.
(A) A schematic representation of TRPM3 channel inhibition by Gβγ. Upon agonist stimulation, released Gβγ directly binds to and inhibits TRPM3 channels. (B) The amount of current blocked upon GPCR stimulation was normalized to the first peak current (±SEM). (C)-(F) Representative voltage-clamp recordings of HEK-293T cells transiently transfected with (C) TRPM3 and M2Rs (D) TRPM3 and β2ARs (E) TRPM3, β2ARs, and Gαs, or (F) TRPM3, β2ARs, Gαs, and Gβγ. A ramp protocol from −100 mV to +100 mV was applied to the cells every second. The currents at +100 mV were plotted. TRPM3 currents were evoked by 10 µM pregnenolone sulfate (PS). M2Rs and β2ARs were stimulated by 10 µM ACh and Iso, respectively.