Receptor for Wnt proteins (PubMed:10557084). Activated by WNT3A, WNT3, WNT1 and to a lesser extent WNT2, but apparently not by WNT4, WNT5A, WNT5B, WNT6, WNT7A or WNT7B (PubMed:10557084). Contradictory results showing activation by WNT7B have been described for mouse (By similarity). Functions in the canonical Wnt/beta-catenin signaling pathway (PubMed:10557084). 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 (PubMed:10557084). 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). (Microbial infection) Acts as a receptor for C.difficile toxin TcdB in the colonic epithelium. Interacts with MYOC (PubMed:19188438). Interacts with WNT7B (By similarity). (Microbial infection) Interacts with C.difficile toxin TcdB; frizzled receptors constitute the major host receptors for TcdB in the colonic epithelium. Expressed in adult heart, placenta, lung, kidney, pancreas, prostate, and ovary and in fetal lung and kidney. 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.