Figure 5.

Processing of mutated Notch molecules transfected into 293T cells. Extracts from 293T cells either untransfected (lane 1) or transfected with full-length Notch1 cDNA (wt, lanes 2 and 6), mutated Notch1 cDNA (m1, mutation RQRR → AAAA; lanes 3 and 7), and Notch1 cDNA carrying the three mutations described in the text (m3 and m′3: lanes 4 and 5 and 8 and 9) in the absence (lanes 2–5) or presence (lanes 6–9) of cotransfected furin cDNA were analyzed by immunoblotting by using the IC antiserum. Positions of full-length Notch (p300) and p120 processing products are indicated. m3 and m′3 correspond to two independent experiments by using the Notch1 triple mutant.