Recombinant Drosophila pseudoobscura pseudoobscura Protein hedgehog (hh-1)

Intercellular signal essential for a variety of patterning events during development. Establishes the anterior-posterior axis of the embryonic segments and patterns the larval imaginal disks. Binds to the patched (ptc) receptor, which functions in association with smoothened (smo), to activate the transcription of target genes wingless (wg), decapentaplegic (dpp) and ptc. In the absence of hh, ptc represses the constitutive signaling activity of smo through fused (fu).; The hedgehog protein N-product constitutes the active species in both local and long-range signaling, whereas the C-terminal product has no signaling activity. It acts as a morphogen, and diffuses long distances despite its lipidation. Heparan sulfate proteoglycans of the extracellular matrix play an essential role in diffusion. Lipophorin is required for diffusion, probably by acting as vehicle for its movement, explaining how it can spread over long distances despite its lipidation.; The hedgehog protein C-product, which mediates the autocatalytic activity, has no signaling activity.