Fig. 3. Asymmetric localisation of core planar polarity proteins in the Drosophila wing and eye. (A) Distribution of core planar polarity proteins in cells of the pupal wing between 24 and 32 hours after prepupa formation (APF). Frizzled (Fz) and Flamingo/Starry Night (Fmi/Stan) are found in distal apicolateral membranes at the level of the adherens junctions, and Van Gogh/Strabismus (Vang/Stbm) and Fmi/Stan are found in proximal membranes. Other proteins are recruited from the cytoplasm to the cell cortex either distally [Dishevelled (Dsh)] or proximally [Prickle (Pk)], or both [Diego (Dgo)]. Actin accumulates and hairs form at the distal cell vertex at 32 hours APF. (B) Comparison of Fz and Vang/Stbm distribution in the wing and eye. Fz is distal and Vang is proximal in pupal wing cells. In the third instar eye disc, Fz is localised on the R3 side of the R3/R4 cell-cell boundary and Vang/Stbm is localised on the R4 side. (Fz and Vang/Stbm are probably also on other membranes of these cells, but this has not been fully characterised.) Thus, an intercellular complex forms across the R3/R4 cell-cell boundary that is probably functionally equivalent to the asymmetric complex across distal-proximal cell boundaries in the wing. (C) Loss of Fmi/Stan largely blocks Fz and Vang/Stbm recruitment to apicolateral cell regions (right, top and bottom). Loss of Dsh, Pk or Dgo blocks the formation of asymmetric proximodistal complexes between 18 and 32 hours APF (middle, top and bottom), resulting in Fz and Vang/Stbm remaining distributed around the circumference of the cells. Photomicrographs at the bottom are confocal sections through the apical regions of pupal wing cells at 28 hours of pupal life, showing Fz-GFP distribution in the adherens junction zone in wild type (left), in a pk^pk-sple-13 mutant (middle) and in a fmi^E59 mutant (right).