Sonic Hedgehog (Shh) C-terminal fragment

Human Shh cDNA encodes a 462 amino acid (aa) residue (45 kDa) precursor protein with a 23 aa signal peptide. An autocatalytic cleavage reaction yields a 19 kDa (residues 24 - 197) amino-terminal fragment (Shh-N), and a 25 kDa (residues 198 - 462) carboxy-terminal domain (Shh-C) . The N-terminal domain retains all known signaling capabilities, while the C-terminal domain is responsible for the intramolecular processing, acting as a cholesterol transferase that covalently transfers the cholesterol molecule to the C-terminus of Shh-N. When Shh is expressed in insect or mammalian cells, a palmitoyl group is also attached to the N-terminal cysteine of Shh-N via an amide linkage.