Figure 3. Activation of MMP-20 or MMP-2 with APMA or MT1-MMP. (A-B) Western blot analysis of proMMP-20 conversion by APMA or MT1-MMP in odontoblasts collected from intact mature human teeth (A) and conditioned odontoblast culture media (B). In the control samples from cells or media, 57-kDa proMMP-20 and 46-kDa active MMP-20 immunoreactive bands were observed. APMA and the soluble catalytic domain of MT1-MMP (MT1-MMP [A]) variable converted the 57-kDa proMMP-20 form into 46-kDa activated MMP-20 after incubation of 6 or 24 hrs. This occurred in both the odontoblasts (A) and conditioned odontoblast culture medium (B). (C-D) Conversion of recombinant human MMP-20 by the catalytic domain of active recombinant MT1-MMP. Western blot analysis (C) and SDS-PAGE with Coomassie Brilliant Blue staining (D) revealed that MT1-MMP converted proMMP-20 into an active MMP-20 after 6 hrs or 24 hrs of incubation. (E-F) MMP-2 activation assay with APMA or MT1-MMP analyzed by gelatin zymography. APMA clearly activated proMMP-2 in odontoblasts (E) and conditioned odontoblast culture medium (F). Soluble catalytic MT1-MMP (A) and soluble catalytic with hemopexin domain MT1-MMP (B) converted proMMP-2 into an active form of MMP-2 in the odontoblasts (E). No clear activation was seen in the conditioned odontoblast culture medium (F). (All samples were incubated for 24 hrs.)
