β(2) Adrenergic Receptor Fluorescent Protein Fusions Traffic to the Plasma Membrane and Retain Functionality

Green fluorescent protein (GFP) has proven useful for the study of protein interactions and dynamics for the last twenty years. A variety of new fluorescent proteins have been developed that expand the use of available excitation spectra. We have undertaken an analysis of seven of the most useful fluorescent proteins (XFPs), Cerulean (and mCerulean3), Teal, GFP, Venus, mCherry and TagRFP657, as fusions to the archetypal G-protein coupled receptor, the β(2) adrenergic receptor (β(2)AR). We have characterized these β(2)AR::XFP fusions in respect to membrane trafficking and G-protein activation. We noticed that in the mouse neural cell line, OP 6, that membrane bound β(2)AR::XFP fusions robustly localized in the filopodia identical to gap::XFP fusions. All β(2)AR::XFP fusions show responses indistinguishable from each other and the non-fused form after isoprenaline exposure. Our results provide a platform by which G-protein coupled receptors can be dissected for their functionality.