Figure 2 |. Optical control of S1P₁-GIRK coupling.

(A) Schematic of selective binding to and activation of S1P₁ receptor by PhotoS1P in trans state, resulting in activation and opening of GIRK channel. (B) A representative single current trace of PhotoS1P evaluated using whole-cell patch clamp recording in HEK293T cells transiently expressing S1P₁ receptors and GIRK channels. Switching illumination between 365 and 450 nm does not induce current in the absence of PhotoS1P. Application of PhotoS1P (100 nM) in trans state induces an inward current, which is reversed by illumination at 365 nm and re-activated by illumination at 450 nm. The current induced by PhotoS1P under 450 nm light is inhibited by the S1P₁ receptor antagonist VPC23019. Currents measured at constant membrane potential of −80 mV. This experiment was repeated 4 times with similar results.