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. Author manuscript; available in PMC: 2017 Jun 1.
Published in final edited form as: Gastroenterology. 2016 Feb 27;150(8):1769–1777. doi: 10.1053/j.gastro.2016.02.066

Figure 3. The hedgehog signaling pathway.

Figure 3

A. The SHH ligand patched 1 constitutively represses SMO, allowing the sequential phosphorylation of Gli by protein kinase A (PKA), glycogen synthase kinase 3 beta (GSK3B), and casein kinase (CK). Phosphorylation of the Gli family zinc finger proteins marks them for ubiquitination and limited proteosomal degradation. N-terminal fragments of Gli proteins translocate to the nucleus where they repress transcription.

B. Binding of SHH to patched 1 prevents its inhibition of SMO. This prevents phosphorylation and degradation of Gli proteins. Full-length Gli proteins translocate to the nucleus and promote transcription.