Abstract 1248 A photosensitive Isoproterenol (OptoIso) delivers spatiotemporally precise cell surface and endomembrane-exclusive beta-adrenergic receptor signaling

Beta (β)-adrenergic G-protein-coupled receptors (GPCRs) are primarily responsible for signaling in the sympathetic nervous system and control numerous body functions, including increased heart rate, pupil dilation, glycogen metabolism, and adrenaline secretion. Using its ligand, isoproterenol, bound β1-AR structure (PDB ID:7S0F), we synthesized a blue light (405 nm) sensitive, novel inactive isoproterenol derivative (OptoIso) with optically deprotectable groups. The goal was to control cell surface and endomembrane β1-AR signaling using light. Our results show that OptoIso efficiently activates β1AR signaling, as indicated by the miniGs protein and nanobody80 (Nb-80) recruitment to the activated cell surface receptor, G-beta gamma translocation, and cAMP production only upon exposure of cells to a few pulses of blue light in the presence of OptoIso. Due to its enhanced cell permeability, OptoIso efficiently entered cells, and blue light exposure after washing cells induced endomembrane-exclusive β1-AR activation at user-defined subcellular endomembrane regions. Given the disease relevance of β1-AR in general, and deep-organelle β1-AR in particular, OptoIso will be a valuable tool for decoding pathological β adrenergic signaling. NIH NIGMS for funding (1R01GM140191).