Patent ID: 7691564

Claim:
A method for detecting G protein coupled receptor signaling in the presence of a test sample, the method comprising: contacting a eukaryotic cell selected from the group consisting of bovine, human, murine, rat, D. discoideum , and ovine cells, with a test sample; monitoring fluorescence resonance energy transfer (FRET) or bioluminescence resonance energy transfer (BRET) in said cell, wherein the eukaryotic cell comprises: (a) a nucleic acid encoding a first fusion protein comprising an α subunit of a heterotrimeric G protein of the eukaryotic cell, wherein a first fluorescent or luminescent protein moiety is inserted between αA and αB helices, or αB and αC helices of the helical domain of said α subunit; and (b) a nucleic acid encoding a second fusion protein comprising a β or γ subunit of the heterotrimeric G protein fused at its N-terminus to a second fluorescent or luminescent protein moiety, wherein the cell expresses a G protein coupled receptor and said first and second fusion proteins and a β or γ subunit of the heterotrimeric G protein which is not part of the first or second fusion protein, wherein said first and second fusion proteins and said β or γ subunit of the heterotrimeric G protein which is not part of the first or second fusion protein form a heterotrimeric G protein comprising an α, β, and γ subunit, wherein the heterotrimeric G protein so formed is capable of binding to said G protein coupled receptor and is capable of FRET or BRET between said first and second fusion proteins; observing a change in FRET or BRET between said first and second fluorescent or luminescent protein moieties upon contact with the test sample, which suggests that a component in the test sample binds to and activates the G protein coupled receptor expressed in the cell.