TI - Wnt , Hedgehog and Junctional Armadillo/beta-Catenin Establish Planar Polarity in the Drosophila Embryo Embryonic Polarity Signaling . AB - To generate specialized structures , cells must obtain positional and directional information . In multi-cellular organisms , cells use the non-canonical Wnt or planar cell polarity ( PCP ) signaling pathway to establish directionality within a cell . In vertebrates , several Wnt molecules have been proposed as permissible polarity signals , but none has been shown to provide a directional cue . While PCP signaling components are conserved from human to fly , no PCP ligands have been reported in Drosophila . Here we report that in the epidermis of the Drosophila embryo two signaling molecules , Hedgehog ( Hh ) and Wingless ( Wg or Wnt1 ) , provide directional cues that induce the proper orientation of Actin-rich structures in the larval cuticle . We further find that proper polarity in the late embryo also involves the asymmetric distribution and phosphorylaTION of Armadillo ( Arm or beta-catenin ) at the membrane and that interference with this Arm PHOSphorylation leads to polarity defects . Our results suggest new roles for Hh and Wg as instructive polarizing cues that help establish directionality within a cell sheet , and a new polarity-signaling role for the membrane fraction of the oncoprotein Arm .