Fig. 2.

Schematic diagram of the Hedgehog signaling pathway. a In the absence of Shh or unstimulated cells, the activity of the transmembrane protein Smo is suppressed by the Hedgehog receptor Ptch. b Binding of Shh to Ptch results in the removal of the inhibitory effect on Smo and consequently activating Smo. Smo then transduces the Shh signal into the cytoplasm. Transduction of the Shh signal into the cytoplasm leads to activation of the Glioblastoma (Gli) family of transcription factors and activation of downstream targets such as Wnt, Snail, and H⁺,K⁺-ATPase