GPCRs Interaction Measurement by Fluorescence Resonance Energy Transfer (FRET)

This is a protocol to determine the physical interaction of a G-protein coupled receptor (GPCR) with itself (homodimerization) or with other GPCR (heterodimerazation) using fluorescence resonance energy transfer (FRET). FRET is a distance-dependent interaction between the electronic excited states of two dye molecules (in this case, CFP and YFP) in which excitation is transferred from a donor molecule (CFP) to an acceptor (YFP) molecule without emission of a photon that can be used to determine interaction among YFP- and CFP-tagged GPCRs. Nowadays, FRET microscopy technique can be used to determine interaction between any proteins that retain biological function when expressed as a fusion to the fluorescent protein.