Frizzled

Frizzled is a family of G protein-coupled receptor proteins that serves as receptors in the Wnt signaling pathway and other signaling pathways. When activated, Frizzled leads to activation of Dishevelled in the cytosol.

Species distribution

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

Function

Frizzled proteins also play key roles in governing cell polarity, embryonic development, formation of neural synapses, cell proliferation, and many other processes in developing and adult organisms. These processes occur as a result of one of three signaling pathways. These include the canonical Wnt/β-catenin pathway, Wnt/calcium pathway, and planar cell polarity (PCP) pathway. Mutations in the human frizzled-4 receptor have been linked to familial exudative vitreoretinopathy, a rare disease affecting the retina at the back of the eye, and the vitreous, the clear fluid inside the eye.

The frizzled (fz) locus of Drosophila coordinates the cytoskeletons of epidermal cells, producing a parallel array of cuticular hairs and bristles. In fz mutants, the orientation of individual hairs with respect both to their neighbours and to the organism as a whole is altered. In the wild-type wing, all hairs point towards the distal tip.