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. Author manuscript; available in PMC: 2016 Aug 9.
Published in final edited form as: Prostate. 2012 Mar 27;72(15):1638–1647. doi: 10.1002/pros.22517

Figure 1. Schematic diagram of the Hh pathway.

Figure 1

A: In the absence of ligand, the transmembrane receptor Patched (Ptch) normally inhibits the signaling function of another transmembrane protein, Smoothened (Smo), thereby blocking the expression of target genes. In that inactive situation, Suppressor of Fused (SuFu) prevents Gli from translocating to the nucleus.

B: In the presence of the ligand Sonic Hedgehog (Shh), the repression of Smo is relieved after binding of Shh to Ptch. Smo further transduces a signal resulting in the release of transcription factor Gli from the cytoplasmic proteins Fused (Fu) and SuFu. In the active situation SuFu is inhibited by Fu and Gli is released, translocates to the nucleus and activates target genes transcription, such as Ptch and Gli1.