FIGURE 4.

The CTD regulates turnover of Ptch proteins. The stability of Ptch proteins in transfected NIH 3T3 cells was assessed by Western analysis of cells treated with cycloheximide (CHX) for the indicated times. Wild-type mouse Ptch1 and Ptch2, Ptch1 substituted with a Ptch2 CTD (Ptch1^C2), Ptch2 substituted with a Ptch1 CTD (Ptch2^C1), Ptch1 deleted of its CTD (Ptch1^ΔC), and Ptch1 with the PPPY sequence in its CTD changed to AAAA (Ptch1^4A) are compared. Red, Ptch1 residues; blue, Ptch2 residues; black, mutated PPPY in CTD.