Cell migration is a process that is essential to animals during their entire lifetime and improper cell migration is implicated in diseased states such as cancer. Primordial germ cell migration in Drosophila melanogaster is an excellent model to study cell migration. The movements of Drosophila primordial germ cells are well documented and some of the molecules involved have been identified. The G protein-coupled receptor (GPCR) trapped in endoderm-1 (tre1) is one of the first genes involved in primordial germ cell migration. The work in this dissertation focuses on the GPCR Tre1, the roles of Tre1 in Drosophila germ cell migration, and how Tre1's structure relates to its function. Chapter 2 describes the mutant allele of tre1, tre1^sctt, and the molecular basis for its phenotype. Chapter 3 discusses the work done to dissect the similarity in phenotypes of tre1^sctt mutant embryos and embryos lacking wunen and wunen2, two lipid phosphate phosphatases. Chapter 4 reports work done to investigate the structural differences between wild-type Tre1 and the mutant protein, Tre1^sctt, to better understand the function of Tre1 in primordial germ cell migration.