Unique Pharmacological Properties of the Kappa Opioid Receptor Signaling Through Gz as Shown with Bioluminescence Resonance Energy Tranfer.

Opioid receptors (ORs) convert extracellular messages to signaling events by coupling to the heterotrimeric G proteins, G• Classic pharmacological methods, such as [S]GTPS binding and inhibition of cyclic AMP production, allow for general opioid characterization, but they are subject to the varying endogenous G proteins in a given cell type. Bioluminescence resonance energy transfer (BRET) technology offers new insight by allowing the direct observation of G subunit-specific effects on opioid pharmacology. Using a Venus-tagged G and nanoluciferase-tagged truncated G protein receptor kinase 3, an increase in BRET signal correlated with OR activation mediated by a specific G protein.

Quantification of light-induced miniSOG superoxide production using the selective marker, 2-hydroxyethidium.

Genetically-encoded photosensitizers produce reactive oxygen species (ROS) in response to light. Transgenic expression of fusion proteins can target the photosensitizers to specific cell regions and permit the spatial and temporal control of ROS production. These ROS-generating proteins (RGPs) are widely used for cell ablation, mutagenesis and chromophore-assisted light inactivation of target proteins.