In the absence of the Hh ligand, the receptor PTCH (Patched) acts to prevent high expression and activity of SMO (Smoothened). When Hh is bound, the repression of SMO is relieved which leads to activation of the GLI transcription factors: activators Gli1 and Gli2 and repressor Gli3. Activated GLI then controls the transcription of hedgehog target genes. Pathway adapted from [http://www.genome.jp/kegg-bin/show_pathway?hsa04340 KEGG] parentid=Q9UMX1; parentsymbol=SUFU; site=HLQERVDkGIETDGS; position=lys257; sitegrpid=5009206; ptm=ub; direction=u a8b signaling pathway pertinent to development PW:0000650 Pathway Ontology 27234298 PubMed SCF (Fbxl17) ubiquitylation of Sufu regulates Hedgehog signaling and medulloblastoma development. EMBO J 2016 Raducu M Fung E Serres S Infante P Barberis A Fischer R Bristow C Thézénas ML Finta C Christianson JC Buffa FM Kessler BM Sibson NR Di Marcotullio L Toftgård R D'Angiolella V signaling pathway PW:0000003 Pathway Ontology Hedgehog signaling pathway PW:0000122 Pathway Ontology