Shh
Developmental stage
First detectable during gastrulation.
Domain
Sonic hedgehog protein N-product
Binds calcium and zinc ions; this stabilizes the protein fold and is essential for protein-protein interactions mediated by this domain.
Sonic hedgehog protein N-product
The Cardin-Weintraub (CW) motif is required for heparan sulfate binding of the solubilized ShhNp (PubMed:23118222). The N-terminal palmitoylated peptide is cleaved at the heparan sulfate-binding Cardin-Weintraub (CW) motif site (PubMed:24522195). The cleavage reduced the interactions with heparan sulfate. The cleavage is enhanced by SCUBE2 (PubMed:24522195).
Function
Sonic hedgehog protein
The C-terminal part of the sonic hedgehog protein precursor displays an autoproteolysis and a cholesterol transferase activity (PubMed:7736596, PubMed:7891723, PubMed:8824192). Both activities result in the cleavage of the full-length protein into two parts (ShhN and ShhC) followed by the covalent attachment of a cholesterol moiety to the C-terminal of the newly generated ShhN (PubMed:8824192). Both activities occur in the reticulum endoplasmic (PubMed:21357747). Once cleaved, ShhC is degraded in the endoplasmic reticulum (PubMed:21357747).
Sonic hedgehog protein N-product
The dually lipidated sonic hedgehog protein N-product (ShhNp) is a morphogen which is essential for a variety of patterning events during development. Induces ventral cell fate in the neural tube and somites (PubMed:11430830, PubMed:24863049). Involved in the patterning of the anterior-posterior axis of the developing limb bud (PubMed:15315762). Essential for axon guidance (PubMed:12679031). Binds to the patched (PTCH1) receptor, which functions in association with smoothened (SMO), to activate the transcription of target genes (By similarity). In the absence of SHH, PTCH1 represses the constitutive signaling activity of SMO (By similarity).
Post-translational modifications
Sonic hedgehog protein
The C-terminal domain displays an autoproteolysis activity and a cholesterol transferase activity (PubMed:7736596, PubMed:7891723, PubMed:8824192). Both activities result in the cleavage of the full-length protein and covalent attachment of a cholesterol moiety to the C-terminal of the newly generated N-terminal fragment (ShhN) (PubMed:7736596, PubMed:7891723, PubMed:8824192). Cholesterylation is required for the sonic hedgehog protein N-product targeting to lipid rafts and multimerization (PubMed:24522195, PubMed:8824192). ShhN is the active species in both local and long-range signaling, whereas the C-product (ShhC) is degraded in the reticulum endoplasmic (PubMed:21357747).
Sonic hedgehog protein N-product
N-palmitoylation by HHAT of ShhN is required for sonic hedgehog protein N-product multimerization and full activity (PubMed:11486055, PubMed:15075292). It is a prerequisite for the membrane-proximal positioning and the subsequent shedding of this N-terminal peptide (PubMed:24522195).
Sonic hedgehog protein N-product
The lipidated N- and C-terminal peptides of ShhNp can be cleaved (shedding) (PubMed:24522195). The N-terminal palmitoylated peptide is cleaved at the Cardin-Weintraub (CW) motif site (PubMed:24522195). The cleavage reduced the interactions with heparan sulfate (PubMed:23118222). The cleavage is enhanced by SCUBE2.
Sequence Similarities
Belongs to the hedgehog family.
Tissue Specificity
Expressed in a number of embryonic tissues including the notochord, ventral neural tube, floor plate, lung bud, zone of polarizing activity and posterior distal mesenchyme of limbs. In the adult, expressed in lung and neural retina.
Cellular localization
- Sonic hedgehog protein
- Endoplasmic reticulum membrane
- Golgi apparatus membrane
- Co-localizes with HHAT in the ER and Golgi membrane.
- Sonic hedgehog protein N-product
- Cell membrane
- Lipid-anchor
- The dual-lipidated sonic hedgehog protein N-product (ShhNp) is firmly tethered to the cell membrane where it forms multimers (PubMed:24522195). Further solubilization and release from the cell surface seem to be achieved through different mechanisms, including the interaction with DISP1 and SCUBE2, movement by lipoprotein particles, transport by cellular extensions called cytonemes or by the proteolytic removal of both terminal lipidated peptides.
Alternative names
Hhg1, Shh, Sonic hedgehog protein, SHH, HHG-1, Shh unprocessed N-terminal signaling and C-terminal autoprocessing domains, ShhNC