Frizzled proteins and the genes that encode them have been identified in an array of animals, from sponges to humans.

The frizzled (fz) locus of Drosophila coordinates the cytoskeletons of epidermal cells, producing a parallel array of cuticular hairs and bristles.

Fz produces an mRNA that encodes an integral membrane protein with 7 putative transmembrane (TM) domains.

This protein should contain both extracellular and cytoplasmic domains, which could function in the transmission and interpretation of polarity information.

[6][7][8] In Drosophila melanogaster, members of the Frizzled family of tissue-polarity genes encode proteins that appear to function as cell-surface receptors for Wnts.