Identification of Novel Regulators for GPCR-signaling via Genome-wide Analysis.

G protein-coupled receptors (GPCRs) are a large family of proteins responsible for receiving and responding to many signals such as smell, light, and hormones. GPCRs are also the target for approximately thirty-four percent of all FDA approved drugs. Therefore, gaining new insight about GPCR signaling regulation can be useful for improving our understanding of cellular physiology and enhancing the effectiveness of the drugs we use. GPCR signaling is highly conserved, enabling the use of model organisms, such as budding yeast Saccharomyces cerevisiae, to study its regulation. Yeast responds to pheromone using a well-characterized GPCR pathway. In this project, we screened a collection of yeast mutants that all had one gene deleted from their genome, using a well-established assay that measures pheromone response. From this screen, we have identified seven novel mutants that clearly and consistently alter the pheromone response. Further analysis of these mutants indicates that some of them affect the pheromone response at the level of or upstream of MAP kinase Fus3. We are in the process of cloning these genes and examining if the abnormal pheromone response and Fus3 activation of these mutants can be rescued. Our analysis suggests that unbiased genome-wide genetic screening remains a viable approach in identifying novel regulators for GPCR-mediated signaling.