Planar polarity from flies to vertebrates.

Planar cell polarity (PCP) has been demonstrated in the epithelium of organisms from flies to humans. Recent research has revealed that the planar organization of cells requires a conserved set of genes, known as the PCP genes. Tbe PCP proteins Frizzled (Fz) and Dishevelled (Dsh) function as key players in PCP signalling. Although Fz and Dsh are also involved in Wingless (Wg)/Wnt signalling, these proteins have independent functions in a non-canonical pathway dedicated to PCP. Reorganization of the cell surface and cytoskeleton is required, and recent work has focused on how cell adhesion molecules (such as Fat, Dachsous and Flamingo) function in this process.