Smoothened is a G protein-coupled receptor protein encoded by the SMO gene of the hedgehog signaling pathway conserved from flies to humans. It is the molecular target of the teratogen cyclopamine. Cellular localization plays an essential role in the function of SMO. Stimulation of the patched receptor by the sonic hedgehog ligand leads to translocation of SMO to the primary cilium. Furthermore, SMO that is mutated in the domain required for ciliary localisation cannot contribute to pathway activation.[3] SMO has also been shown to bind the kinesin motor protein Costal-2 and play a role in the localization of the Ci (Cubitus interruptus transcription factor) complex. SMO can function as an oncogene. Activating SMO mutations can lead to unregulated activation of the hedgehog pathway and cancer.
Glasdegib (PF-04449913) is a potent and orally bioavailable smoothened inhibitor. Glasdegib (PF-04449913) binds to human SMO (amino acids 181-787) with an IC50 of 4 nM.
Erismodegib diphosphate (LDE225 diphosphate) is a potent and selective Smo antagonist with IC50 of 1.3 nM and 2.5 nM for mouse and human Smo in binding assay, respectively.
Jervine(11-Ketocyclopamine) is a naturally occuring steroidal alkaloid that causes cyclopia by blocking sonic hedgehog(Shh) signaling; Jervine is an inhibitor of Smo.
BMS-833923 (XL-139) is an orally bioavailable small-molecule inhibitor of Smoothened with potential antineoplastic activity; inhibits BODIPY cyclopamine binding to SMO in a dose-dependent manner with an IC50 of 21 nM.
PF-5274857 is a potent and selective Smoothened (Smo) antagonist, inhibits Hedgehog (Hh) signaling with IC50 and Ki of 5.8 nM and 4.6 nM, respectively, and can penetrate the blood–brain barrier.
