Abstract: The invention resides in part in the discovery that G proteins other than G?15 couples to T1R and T2R taste receptors, particularly Gi proteins such as G?i. Related to this discovery, the invention provides cell-based assay methods for identifying compounds that modulate the activity of specific T1R or T2R taste receptors or which modulate the effect of other T1R or T2R modulators on T1R or T2R activity. These assay methods preferably detect the effect of a putative T1R or T2R modulator compound on MAPK activation cAMP accumulation, or adenylyl cyclase activity or another signaling pathway regulated by Gi proteins. The level of MAPK activation, cAMP accumulation or adenylyl cyclase is preferably determined by immunoassay methods that use ligands (monoclonal or polyclonal antibodies) that specifically bind an activated (phosphorylated) MAPK, cAMP, or adenylyl cyclase.

Abstract: Screening assays, preferably high throughput, are provided that screen libraries of candidate compounds to identify agonists, antagonists, enhancers or modulators of taste receptors (bitter, sweet or savory (umami) taste receptor) using test cells that co-express at least one functional taste receptor and an olfactory cyclic nucleotide-gated channel (oCNGC). (The oCNGC preferably comprises at least one mutation in one or more subunits that renders the resultant oCNGC more sensitive to CAMP (which in turn enhances the sensitivity of assay using this oCNGC). These taste modulatory compounds are identified based on their effect on oCNGC activity, e.g., using fluorimetric assays that screen for changes in intracellular calcium or sodium concentration in test cells that co-express at least one taste receptor, oCNGC and a G?i/o protein.

Abstract: The invention resides in part in the discovery that G proteins other than G?15 couples to T1R and T2R taste receptors, particularly Gi proteins such as G?i. Related to this discovery, the invention provides cell-based assay methods for identifying compounds that modulate the activity of specific T1R or T2R taste receptors or which modulate the effect of other T1R or T2R modulators on T1R or T2R activity. These assay methods preferably detect the effect of a putative T1R or T2R modulator compound on MAPK activation, cAMP accumulation, or adenylyl cyclase activity or another signaling pathway regulated by Gi proteins. The level of MAPK activation, cAMP accumulation or adenylyl cyclase is preferably determined by immunoassay methods that use ligands (monoclonal or polyclonal antibodies) that specifically bind an activated (phosphorylated) MAPK, cAMP, or adenylyl cyclase.

Abstract: The invention resides in part in the discovery that G proteins other than G&agr;15 couples to T1R and T2R taste receptors, particularly Gi proteins such as G&agr;i. Related to this discovery, the invention provides cell-based assay methods for identifying compounds that modulate the activity of specific T1R or T2R taste receptors or which modulate the effect of other T1R or T2R modulators on T1R or T2R activity. These assay methods preferably detect the effect of a putative T1R or T2R modulator compound on MAPK activation, cAMP accumulation, or adenylyl cyclase activity or another signaling pathway regulated by Gi proteins. The level of MAPK activation, cAMP accumulation or adenylyl cyclase is preferably determined by immunoassay methods that use ligands (monoclonal or polyclonal antibodies) that specifically bind an activated (phosphorylated) MAPK, cAMP, or adenylyl cyclase.