Getting Hedgehogs Where They Need to Go: Cleavage Activates Dispatched for Sonic Hedgehog Release

Abstract

Hedgehog ligands activate an evolutionarily conserved signaling pathway that provides instructional cues during tissue morphogenesis, and when corrupted, contributes to developmental disorders and cancer. The transmembrane protein Dispatched is an essential component of the machinery that deploys Hedgehog family ligands from producing cells, and is required for Hedgehog morphogen gradient formation and signaling to long‐range targets. Despite this crucial role, regulatory mechanisms controlling Dispatched activity remain largely undefined. We reveal that Dispatched is activated by Furin‐mediated cleavage at a conserved processing site in its first extracellular loop. CRISPR/Cas9 gene editing was used to generate transgenic mice harboring cleavage site mutation in the endogenous Dispatched locus. Homozygous animals show neuronal patterning phenotypes and decreased viability, confirming a requirement for Dispatched processing in vivo. As such, Furin serves as a crucial post‐translational regulator of Dispatched activity in Hedgehog‐producing cells during tissue morphogenesis.Support or Funding InformationThis research was supported by funding from the National Institute of General Medical Sciences grants R01GM114049, R35GM122546.