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Wu, J and Mlodzik, M (2008) The frizzled extracellular domain is a ligand for Van Gogh/Stbm during nonautonomous planar cell polarity signaling. Dev. Cell 15:462-9

The Frizzled (Fz) receptor is required cell autonomously in Wnt/beta-catenin and planar cell polarity (PCP) signaling. In addition to these requirements, Fz acts nonautonomously during PCP establishment: wild-type cells surrounding fz(-) patches reorient toward the fz(-) cells. The molecular mechanism(s) of nonautonomous Fz signaling are unknown. Our in vivo studies identify the extracellular domain (ECD) of Fz, in particular its CRD (cysteine rich domain), as critical for nonautonomous Fz-PCP activity. Importantly, we demonstrate biochemical and physical interactions between the FzECD and the transmembrane protein Van Gogh/Strabismus (Vang/Stbm). We show that this function precedes cell-autonomous interactions and visible asymmetric PCP factor localization. Our data suggest that Vang/Stbm can act as a FzECD receptor, allowing cells to sense Fz activity/levels of their neighbors. Thus, direct Fz-Vang/Stbm interactions represent an intriguing mechanism that may account for the global orientation of cells within the plane of their epithelial field.

PubMed PMC2814157 Online version:10.1016/j.devcel.2008.08.004

Animals; Cell Line; Cell Polarity/physiology; Drosophila Proteins/genetics; Drosophila Proteins/metabolism; Drosophila melanogaster/genetics; Drosophila melanogaster/metabolism; Frizzled Receptors/chemistry; Frizzled Receptors/genetics; Frizzled Receptors/metabolism; Ligands; Membrane Proteins/genetics; Membrane Proteins/metabolism; Protein Structure, Tertiary; Recombinant Fusion Proteins/genetics; Recombinant Fusion Proteins/metabolism; Signal Transduction/physiology; Wing/cytology; Wing/physiology