Abstract: The invention provides recombinant cells that have been engineered such that ligand stimulation of a receptor expressed by the cells leads to amplified signal transduction responses. In one embodiment, the receptor-expressing cells have been engineered to carry a heterologous DNA construct comprising a gene encoding a protein that activates the signal transduction pathway, which gene is operatively linked to a promoter that is responsive to activation of the signal transduction pathway. Stimulation of the receptor by a ligand leads to expression of the heterologous DNA construct encoding the protein that activates the signal transduction pathway such that signals generated by ligand binding to the receptor are amplified. Preferred cells are yeast cells expressing heterologous G protein coupled receptors functionally coupled to the yeast pheromone response pathway and overexpressing Ste5p, Ste4p, Ste12p, Ste11p or a dominant truncation allele of Ste20 via a pheromone-responsive promoter.

Abstract: The invention provides recombinant cells that have been engineered such that ligand stimulation of a receptor expressed by the cells leads to amplified signal transduction responses. In one embodiment, the receptor-expressing cells have been engineered to carry a heterologous DNA construct comprising a gene encoding a protein that activates the signal transduction pathway, which gene is operatively linked to a promoter that is responsive to activation of the signal transduction pathway. Stimulation of the receptor by a ligand leads to expression of the heterologous DNA construct encoding the protein that activates the signal transduction pathway such that signals generated by ligand binding to the receptor are amplified. Preferred cells are yeast cells expressing heterologous G protein coupled receptors functionally coupled to the yeast pheromone response pathway and overexpressing Ste5p, Ste4p, Ste12p, Ste11p or a dominant truncation allele of Ste20 via a pheromone-responsive promoter.