Activation of interstitial collagenase, MMP-1, by Staphylococcus aureus cells having surface-bound plasmin: a novel role of plasminogen receptors of bacteria

Plasmin, the enzymatically active form of plasminogen, can activate several matrix metalloproteinases (MMPs). In this study, we investigated the activ ation of MMP-1, one of the major interstitial collagenases, by plasmin whic h was generated on the surface of Staphylococcus aureus cells. Plasmin boun d to plasminogen receptors on S, aureus degraded the major I-125-labeled 55 -kDa proMMP-1 into the 42-kDa form corresponding to the size of active MMP- 1. MMP-1 formed by S, aureus-bound plasmin was also enzymatically active as judged by digestion of the synthetic collagenase substrate, DNP-Pro-Leu-Gl y-Leu-Trp-Ala-D-Arg-NH2. The finding that, in MMP-1 molecules generated eit her by soluble plasmin or by S, aureus-bound plasmin, the amino-terminal am ino acid sequences were identical indicated that the activation mechanisms of the two plasmin forms do not differ from each other. The present observa tions emphasise and broaden the physiological importance of bacterial plasm inogen receptors, In addition to direct proteolytic effects on components o f the extracellular matrix, receptor-bound plasmin is also capable of initi ating an MMP-1-dependent matrix-degrading enzymatic cascade. (C) 1999 Feder ation of European Biochemical Societies.