The Tag:LBD(NTRK3) entry in FlyBase represents the ligand-binding ectodomain of the Homo sapiens NTRK3 gene (HGNC:8033). Tag:LBD(NTRK3) is bound specifically by Tag:LIG(NTF3). This property can be used to study the mechanisms of signal transduction, by replacing the ligand-binding ectodomain of a receptor of interest with Tag:LBD(NTRK3) and replacing the receptor-binding domain of the corresponding ligand with Tag:LIG(NTF3) (FBrf0237506).