Used in research to study Wnt signaling pathways, particularly in angiogenesis and retinal vascular development. Binds to Norrin and Wnt ligands, enabling investigation of receptor-ligand interactions and their role in diseases like familial exudative vitreoretinopathy (FEVR). Employed in protein binding assays, ELISA, and surface plasmon resonance (SPR) to measure interaction kinetics. Also used as an antigen for antibody development and in structural studies to understand FZD receptor function.