Figure 3.

New EXEXXXL motif in the CT of human PC7 is important for its cleavage activity. A, alignment of the CT between aa 717 and 753 (vertical lines) from different species: human, rat, mouse, and Xenopus. Conserved amino acids between species are noted with stars (identical) and either single dots (similar) or double dots (similar functionality). B and C, Western blot analysis of cell lysates (cells) and media (med) after overexpression of hTfR1-V5 with empty vector, hPC7, its truncated form without the CT (ΔCT) or different CT mutants in HEK293 cells. Normalization was performed using the hTfR1-V5 shed by hPC7 as a reference. The main mutants composing the EXEXXXL motif are annotated by a star. These results are representative of three independent experiments. Error bars indicate averaged values ± S.D. *, p < 0.1; **, p < 0.01; ***, p < 0.001, ns, not significant (Student's t test).