Receptor for Wnt proteins. Activated by WNT3A, WNT3, WNT1 and to a lesser extent WNT2, but apparently not by WNT4, WNT5A, WNT5B, WNT6 or WNT7A. Contradictory results have been reported for activation by WNT7B. Functions in the canonical Wnt/beta-catenin signaling pathway. The canonical Wnt/beta-catenin signaling pathway leads to the activation of disheveled proteins, inhibition of GSK-3 kinase, nuclear accumulation of beta-catenin and activation of Wnt target genes (By similarity). A second signaling pathway involving PKC and calcium fluxes has been seen for some family members, but it is not yet clear if it represents a distinct pathway or if it can be integrated in the canonical pathway, as PKC seems to be required for Wnt-mediated inactivation of GSK-3 kinase. Both pathways seem to involve interactions with G-proteins. May be involved in transduction and intercellular transmission of polarity information during tissue morphogenesis and/or in differentiated tissues (Probable). Interacts with MYOC (By similarity). Interacts with WNT7B (By similarity). Widely expressed. Most abundant in kidney, liver, uterus, ovary and heart. Lower levels seen in brain and intestine. Extremely low in calvaria, mammary glands and testis. Expressed predominantly in neonatal tissues, at lower levels in adult. 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. Ubiquitinated by ZNRF3, leading to its degradation by the proteasome. Belongs to the G-protein coupled receptor Fz/Smo family. Activation by specific Wnt family members may depend on the cells used for the experiment. Contradictory results have been reported for activation by WNT7B in human and mouse.