Cyclopamine (ethanol solution), Hh signaling inhibitor

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

The Smoothened (SMO) protein also known as Sonic Hedgehog receptor plays a mechanical role in the Hedgehog (Hh) signaling pathway. This protein acts as a transmembrane receptor that transmits signals from the cell surface to the interior. Smoothened has a molecular mass of approximately 86 kDa and is expressed in several tissues including the brain kidney and liver. Its activity requires the presence of another protein Patched which regulates Smoothened by inhibiting or permitting its signaling depending on Hedgehog ligand binding.

Biological function summary

Smoothened is essential for the Hh signaling pathway which is pivotal for embryonic development and tissue regeneration. In this context Smoothened participates in a complex that includes Patched and Gli family transcription factors. This complex orchestrates the transcription of target genes necessary for cellular proliferation differentiation and tissue organization. Smoothened’s role in activating transcription factors makes it integral to modulating gene expression in response to external Hh signals.

Pathways

Smoothened is a central component of the Hedgehog signaling pathway which plays an important role in cell differentiation and organogenesis. Two of the significant pathways it influences are the Sonic Hedgehog (Shh) and Indian Hedgehog (Ihh) signaling pathways. Within these pathways Smoothened interacts closely with the protein Patched which inhibits Smoothened in the absence of Hedgehog ligands. The downstream activation of Smoothened results in the modulation of Gli transcription factors altering the expression of various developmental genes.

Smoothened is closely linked to conditions such as basal cell carcinoma and medulloblastoma. Dysregulation or mutations in Smoothened can lead to aberrant activation of Hedgehog signaling contributing to the development and progression of these cancers. The protein Gli as part of the same signaling cascade is also heavily involved in the transcriptional changes associated with these disorders. Inhibitors like Cyclopamine sometimes in an ethanol solution target Smoothened to mitigate its pathological signaling and offer therapeutic approaches for these types of cancers.