Abstract
Frizzled receptors (FZDs) are 7-pass transmembrane proteins and members of the G protein-coupled receptor (GPCRs) superfamily. They are classified as WNT receptors and show specific and dynamic expression during different embryonic development stages of invertebrates and vertebrates. They are required in the regulation of developmental processes such as cell specification, cell polarity, and neural patterning in Drosophila, zebrafish, Xenopus, mice, humans, and other animals. The dysfunction of FZDs causes several diseases, including cancer, neural tube defects, and neural degeneration. This review focuses on the structure, signaling, and WNT binding specificity of FZDs as well as their roles in development and diseases, including cancer, embryonic defects, and neurodegenerative disorders. Furthermore, the use of FZDs as potential therapeutic targets for various human diseases is discussed. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).