title: Genetic and biochemical definition of the Hedgehog receptor.
abstract: Although the transporter-like protein Patched (Ptc) is genetically implicated in reception of the extracellular Hedgehog (Hh) protein signal, a clear definition of the Hh receptor is complicated by the existence of additional Hh-binding proteins and, in Drosophila, by the lack of physical evidence for direct binding of Hh to Ptc. Here we show that activity of Ihog (Interference hedgehog), or of its close relative Boi (Brother of Ihog), is absolutely required for Hh biological response and for sequestration of the Hh protein to limit long-range signaling. We demonstrate that Ihog interacts directly with Ptc, is required for presentation of Ptc on the cell surface, and that Ihog and Ptc are both required for high-affinity Hh binding. On the basis of their joint roles in ligand binding, signal transduction, and receptor trafficking, we conclude that Ihog and Ptc together constitute the Drosophila Hh receptor.
authors.affiliation: Department of Developmental Biology, Institute for Stem Cell Biology and Regenerative Medicine, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zheng
authors.forename: Randall K
authors.initials: RK
authors.lastname: Mann
authors.forename: Navdar
authors.initials: N
authors.lastname: Sever
authors.forename: Philip A
authors.initials: PA
authors.lastname: Beachy
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D002478:Cells, Cultured; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C510880:iHog protein, Drosophila; C070844:ptc protein, Drosophila