Patent ID: 7455982

Claim:
A method of detecting G protein-coupled receptor (GPCR) pathway activity, comprising: providing at least one cell that expresses a GPCR and a plurality of conjugated proteins, each of the plurality of conjugated proteins formed by conjugating an arrestin protein and a detectable molecule, the plurality of conjugated proteins being distributed evenly in the cytoplasm of the at least one cell; obtaining a first image of the at least one cell by detecting an amount of energy emitted from the detectable molecules and storing a value relative to the amount of energy; providing a threshold intensity such that the energy emitted from detectable molecules distributed evenly in the cytoplasm are excluded; treating the at least one cell with a test compound; obtaining a second image of the at least one cell by detecting an amount of energy emitted from the detectable molecules and storing a value relative to the amount of energy; and comparing the first image and the second image to detect the localization of at least some of the plurality of conjugated proteins at at least one of endocytic vesicles and endosomes, wherein a difference between the value relative to the amount of energy of the detectable molecules of the first image and the value relative to the amount of energy of the detectable molecules of the second image detects the localization, thereby detecting GPCR pathway activity.