The Ihog Cell-Surface Proteins Bind Hedgehog and Mediate Pathway Activation

摘要: The ihog gene (interference hedgehog), identified by RNA interference in Drosophila cultured cells, encodes a type 1 membrane protein shown here to bind and mediate response the active Hedgehog (Hh) signal. mutations produce defects characteristic of Hh signaling loss embryos imaginal discs, epistasis analysis places action at or upstream negatively acting receptor component, Patched (Ptc). first two extracellular fibronectin III (FNIII) domains Ihog mediates specific interaction with vitro, but second FNIII domain is additionally required for vivo activity Ihog-enhanced binding cells coexpressing Ptc. Other members family, including Boi mammalian CDO BOC, also interact ligands via domain, thus identifying an evolutionarily conserved family proteins that function signal response.