Receptor for Wnt proteins. Most of frizzled receptors are coupled to the beta-catenin canonical signaling pathway, which 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. Expressed in embryonic and adult heart, lung, chondrocytes and brain. Also expressed in the developing gastrointestinal tract (strongest in foregut), much weaker expression in the adult. No expression in fetal liver and adult spleen. Up-regulated in esophageal squamous cell carcinomas. 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.