The frizzled gene family belong to Class F GPCRs. Frizzled GPCRs are characterized by a large N-terminal extracellular domain containing a cysteine-rich ligand-binding domain. The frizzled genes were first identified in Drosophila. Frizzled proteins are receptors for secreted Wnt proteins, as well as other ligands, and also play a critical role in the regulation of cell polarity. Frizzleds function in three distinct signaling pathways - the planar cell polarity pathway, the canonical Wnt/β-catenin pathway, and the Wnt/calcium pathway. (Adapted from FBrf0222139).