Inhibitor of Sonic hedgehog (Shh) signaling; antagonizes smoothened receptor activity (KD = 12 nM). Displays allosteric binding characteristics similar to SANT-1 (Cat. No. 1974). Displaces smo-[3H]SAG-1.3 and -[3H]Cyclopamine binding (Ki values are 7.8 nM and 8.4 nM respectively).