FIGURE 2.

Serine protease activity is required for conversion of 135 kDa CDCP1 to 70 kDa. Anti-Flag Western blot analysis of lysates from HeLa-CDCP1-Flag cells untreated or cultured for 24 h in PC3 cell-conditioned medium that was either untreated or had been supplemented with (A) Complete EDTA-free protease inhibitor mixture or (B) PMSF, aprotinin, TLCK, or TPCK, (C) leupeptinin, (D) GM6001, (E) pepstatin, or (F) E-64 at the indicated concentrations. Arrows indicate 70 and 135 kDa CDCP1. Anti-GAPDH Western blot analysis was performed to examine protein loading.