Receptor for Wnt proteins. Acts in both canonical and non-canonical Wnt pathways. Although different papers report differing Wnt preferences, wnt5a, wnt8b and wnt11 have been proposed as synergists. In the canonical Wnt pathway, acts via beta-catenin to promote the expression of the dorsal genes siamois, twin and nodal3 and to establish the dorsal axis of the embryo and induce dorsal mesoderm formation. In a non-canonical Wnt/planar cell polarity (PCP) pathway, acts with sdc4 and dvl2/dsh to regulate convergent extension cell movements during gastrulation. Triggers phosphorylation of dvl2/dsh and its translocation to the plasma membrane. In a third branch of Wnt signaling, acts in a non-canonical pathway via trimeric G proteins, and independently of dvl2/dsh, to recruit protein kinase C (PKC) to the membrane and thus activate PKC. PKC signaling controls cell sorting and tissue separation during gastrulation. Interacts with wnt11 and sdc4. The extracellular domain interacts with the extracellular domain of pcdh8/papc (By similarity). Interacts (via C-terminus) with dvl1 (via PDZ domain). Associated to the plasma membrane in the presence of FZD7 and phosphatidylinositol 4,5-bisphosphate (PIP2). Localized in recycling endosomes in other conditions. During gastrulation, broadly expressed on the dorsal side of the embryo in deep mesodermal cells surrounding the blastopore lip and in presumptive anterior neuroectoderm. During neurulation, localized to the cranial neural crest and heart field where expression is retained at later stages in addition to new areas of expression in the neural tube, pronephros and tailbud. At tailbud stage, expressed in the pronephric duct, and broad head expression becomes more restricted to the hindbrain. In tadpoles, strongly expressed in the eye and the pericardium and myocardium of the developing heart. Lys-Thr-X-X-X-Trp motif interacts with the PDZ domain of Dvl (Disheveled) family members and is involved in the activation of the Wnt/beta-catenin signaling pathway. The FZ domain is involved in binding with Wnt ligands. The extracellular domain interacts with Wnt proteins and the intracellular C-terminus transmits the Wnt signal. Belongs to the G-protein coupled receptor Fz/Smo family.