Abstract: Methods of detecting G protein-coupled receptor (GPCR) activity in vitro and in vivo are provided. In one embodiment, the method includes providing at least one cell that expresses a GPCR and a plurality of conjugated proteins. Each of the plurality of conjugated proteins is formed by conjugating an arrestin protein and a detectable molecule. The plurality of conjugated proteins are substantially evenly distributed in the cytoplasm of the at least one cell. A first image of the at least one cell is obtained by detecting an amount of energy emitted from the detectable molecules and storing a value relative to the amount of energy. The at least one cell is treated with an agonist. A second image of the at least one cell is obtained. The first image and the second image are compared to detect the localization of at least some of the plurality of conjugated proteins at endocytic vesicles and/or endosomes.

Abstract: The present invention relates to modified G-protein coupled receptors (GPCRs). The modified GPCRs of the present invention include GPCRs that have been modified to have altered DRY motifs such that the modified GPCRs are constitutively desensitized. As such, the modified GPCRs of the present invention preferably localize to endocytic vesicles or endosomes in an agonist-independent manner. The invention also relates to methods of screening compounds and sample solutions for GPCR activity using the modified GPCRs.

Abstract: Methods of detecting G protein-coupled receptor (GPCR) activity in vitro and in vivo are provided. In one embodiment, the method includes providing at least one cell that expresses a GPCR and a plurality of conjugated proteins. Each of the plurality of conjugated proteins is formed by conjugating an arrestin protein and a detectable molecule. The plurality of conjugated proteins are substantially evenly distributed in the cytoplasm of the at least one cell. A first image of the at least one cell is obtained by detecting an amount of energy emitted from the detectable molecules and storing a value relative to the amount of energy. The at least one cell is treated with an agonist. A second image of the at least one cell is obtained. The first image and the second image are compared to detect the localization of at least some of the plurality of conjugated proteins at endocytic vesicles and/or endosomes.

Abstract: The present invention relates to compounds that alter GPCR internalization and new methods for their identification. Compounds of this invention include modified phosphoinositide 3-kinase (PI3K), modified HEAT domain, modified &bgr;-adrenergic receptor kinase 1 (&bgr;ARK1), as well as other peptides or small molecules that alter GPCR internalization. The present invention also includes the use of such compounds to treat GPCR-related diseases, such as cardiovascular disease, heart failure, asthma, nephrogenic diabetes insipidus, or hypertension.

Abstract: The present invention relates to modified G-protein coupled receptors (GPCRs). The modified GPCRs of the present invention include GPCRs that have been modified to have altered DRY motifs such that the modified GPCRs are constitutively desensitized. As such, the modified GPCRs of the present invention preferably localize to endocytic vesicles or endosomes in an agonist-independent manner. The invention also relates to methods of screening compounds and sample solutions for GPCR activity using the modified GPCRs.

Abstract: Methods of detecting G protein-coupled receptor (GPCR) activity in vitro and in vivo are provided. In one embodiment, the method includes providing at least one cell that expresses a GPCR and a plurality of conjugated proteins. Each of the plurality of conjugated proteins is formed by conjugating an arrestin protein and a detectable molecule. The plurality of conjugated proteins are substantially evenly distributed in the cytoplasm of the at least one cell. A first image of the at least one cell is obtained by detecting an amount of energy emitted from the detectable molecules and storing a value relative to the amount of energy. The at least one cell is treated with an agonist. A second image of the at least one cell is obtained. The first image and the second image are compared to detect the localization of at least some of the plurality of conjugated proteins at endocytic vesicles and/or endosomes.