The present invention provides GPCR polypeptides and polynucleotides, recombinant materials, and transgenic mice, as well as methods for their production. The polypeptides and polynucleotides are useful, for example, in methods of diagnosis and treatment of diseases and disorders. The invention also provides methods for identifying compounds (e.g., agonists or antagonists) using the GPCR polypeptides and polynucleotides of the invention, and for treating conditions associated with GPCR dysfunction with the GPCR polypeptides, polynucleotides, or identified compounds. The invention also provides diagnostic assays for detecting diseases or disorders associated with inappropriate GPCR activity or levels.