FIGURE 6.

The ΔML mutant of Ptch1 binds N-Shh-ligand. A, the ability of the ΔML mutant to bind to N-Shh ligand was determined by assaying alkaline phosphatase activity. The ΔML mutant binds to the AP-N-Shh protein with an avidity similar to wild-type Ptch1. AP-R154E, a mutant of Shh that does not bind to Ptch1, did not bind to the ΔML mutant, showing specificity of ligand binding. B, Western blot probed for N-Shh to show comparable levels of protein in AP-N-Shh and AP-R154E conditioned media. ***, p < 0.001.