Frizzle(FRZ) was first identified in Drosophila and named as such for twisting together with wingless-type mice mammary tumor virus integration site family(WNT). FRZ is a family of cell surface receptors of WNT consisting of three regions; this family is also a member of the G protein-coupled receptor(GPCR) family for having or missing some basic GPCR structures. FRZ signaling pathways can be divided into canonical and non-canonical signaling pathways; the former relies on transcription regulatory factor β-catenin. FRZ proteins include FRZ1-10; these proteins have a wide regulatory functional range and play important roles not only at the cellular level, such as in embryo development, stem cell differentiation, and organogenesis, but also in maintaining tissue homeostasis, regeneration, plasticity, and restoration. The agonists, antagonists, and co-receptors of the WNT/FRZ signaling pathway are assumed to be potential targets for treating several types of serious diseases, such as cancer, neurodegenerative diseases, and osteoporosis. WNT/FRZ-related signaling pathways are complicated, and the effects of signaling pathway activation, their potential mechanisms, and the related molecules are unclear. Therefore, exploration of the specificity of the pathways and quantification of the reactions, system positioning, and downstream events are important; more comprehensive and in-depth studies are needed to shed light on these issues.
