INVOLVEMENT OF PA PLASMIN SYSTEM IN THE PROCESSING OF PRO-MMP-9 AND IN THE 2ND STEP OF PRO-MMP-2 ACTIVATION/

Pro-MMP2 activation is a two-step process resulting in (1) an intermed iate 64 kDa form generated by the MT1-MMP activity, and (2) a mature 6 2 kDa form. Addition of plasminogen to HT1080 cells cultured under var ious conditions, or to their membrane preparation, induced a complete conversion of the intermediate MMP-2 form to the mature one, and proce ssing of pro-MMP-9. The pro-MMP-2 activation was inhibited by plasmin inhibitors and anti-uPA antibody. These results provide evidence for i nvolvement of the PA/plasmin system in the second step of MMP-2 activa tion. (C) 1997 Federation of European Biochemical Societies.