Frizzled
Frizzled (Fz) is probably the most interesting protein we study. Frizzled is required to localise the other core proteins to the junctions and is also used in signalling to neighbouring cells to corrdinate polarity. However, we still know very little about what it does and how it does this.
Frizzled is a seven pass transmembrane protein.
Hairs on the surface of a wing from a fly lacking Frizzled activity. Loss of the Frizzled receptor does not block cell polarisation, but does help prevent the proper long-range co-ordination of cell polarity, such that the hairs are arranged in swirling patterns instead of pointing distally.
A clone of cells lacking Strabismus activity - a protein required for non canonical Frizzled activity (marked bt lack of green staining), disrupts the polarity of hairs in the neighbouring cells (stained red) and the site of localisation of the Flamingo protein within cells (stained blue).
What is the role of frizzled during the establishment of planar polarity?
Frizzled is required along with Strabismus for intercellular signalling (Strutt 2007, Developmental Biology).