Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
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Receptors of the Frizzled family transduce important signals during animal development and are conserved from sponges to humans. Frizzled receptors belong to the superfamily of G protein-coupled receptors (GPCRs), but until recently were considered G protein-independent in their signaling. In the present article we review the extensive knowledge demonstrating the functions of trimeric G proteins in Frizzled signal transduction in vertebrates and lower animals. Other structural and functional similarities of Frizzled receptors and the GPCRs are also discussed.