The Hh-signaling pathway. (a) A diagram of the Hh-signaling pathway, showing the site of action of the agonists (green) and antagonists (red) discussed in the text, as well as many additional factors that affect the pathway. Abbreviations: CK1, Casein kinase 1; Cos2, Costal2 ; Dyrk1, dual-specificity Yak1-related kinase 1; GSK3, Glycogen synthase kinase 3; Fu, Fused; Gas1, growth arrest specific 1; Hh, Hedgehog; Hip, Hedgehog-interacting protein 1; Rab23, a Rab-family Ras-like GTPase associated with vesicle traffic; Ptc, Patched1; PKA, Protein kinase A; Smo, Smoothened; SuFu, Suppressor of Fused. (b) A schematic generalized view of the regulation of Gli activator (Gli-act) and Gli repressor (Gli-rep) forms by Hh signaling. See [2-4] for further details.