Cells are engineered to stably or transiently express T1R2 and T1R3 polypeptides, desirably in association with a G protein. The resultant heteromeric taste receptor is a sweet taste receptor and responds to sweet taste stimuli such as artificial and natural sweeteners, e.g., saccharin. The invention provides a preferred mammalian cell lines, e.g., HEK-293 cells that stably express T1R2/T1R3 and G.sub..alpha.15 under inducible conditions. These cells are useful in cell-based assays for identifying compounds that elicit or modulate sweet taste.