Developmental Signals - Sonic hedgehog
Introduction
(SHH) A secreted growth factor that binds patched (ptc) receptor on cell membrane. This protein has many different functions in different tissues of the developing embryo, the main role would be of establishing "pattern". SHH name derives from homology to the original fruitfly (drosophila) "hedgehog" mutation, where these flies have hairs located in regions (ventral) which are normally hair-free, and therefore have a disrupted body pattern.
Sonic Hedgehog (SHH) was isolated by homology to the Hh gene. SHH is a true signaling switch used in differentiating subpopulations of cells throughout the embryo. Depending on where the signal is being secreted, how far away the responsive cell population is and how SHH is proteolytically cleaved, will determine SHH function. SHH binds to the membrane receptors Patched (ptc) and BOC/CDON.
Nomenclature note lower case shh for other species, upper case SHH in humans.
Functions
Developmental patterning signal.
Neural
SHH is secreted by the notochord, ventralizes the neural tube, inducing the floor plate and motor neurons.
- neural crest cell survival in the foregut endoderm of jaw development PNAS
Limb
SHH is secreted by the zone of polarizing activity (ZPA) organizing limb axis formation.
Other
SHH has still others roles in organ development in lung, pancreas.
Signaling pathway
The secreted protein binds to the cell surface membrane protein the patched receptor (ptc).
Links
- UNSW Embryology - Molecular Factors - sonic hedgehog | Molecular Notes | Musculoskeletal Notes | Neural Notes
- OMIM - SONIC HEDGEHOG
Cite this page: Hill, M.A. (2024, April 19) Embryology Developmental Signals - Sonic hedgehog. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Developmental_Signals_-_Sonic_hedgehog
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
