Stromelysins

Stromelysins are a subset of matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases that remodel the extracellular matrix (ECM). The term traditionally refers to MMP-3 (stromelysin-1) and MMP-10 (stromelysin-2); some classifications also include MMP-11 (often called stromelysin-3). These enzymes cleave a broad range of ECM components, including proteoglycans, laminin, fibronectin, and various non-fibrillar collagens, and can activate other MMPs, amplifying proteolysis.

Biochemically, stromelysins are synthesized as inactive zymogens and require proteolytic activation. They possess a catalytic zinc-binding motif in their catalytic domain and a hemopexin-like C-terminal domain that influences substrate specificity. Activation is tightly regulated by tissue inhibitors of metalloproteinases (TIMPs) and by transcriptional control via cytokines and growth factors.

Physiological roles include normal tissue remodeling, embryonic development, wound healing, and bone remodeling. Pathologically, upregulation of stromelysins is associated with inflammatory diseases (e.g., rheumatoid arthritis), cancer invasion and metastasis, and periodontal disease.

Therapeutic relevance: MMP inhibitors were investigated for cancer and inflammatory diseases, but clinical success has been limited due to adverse effects and broad activity. Research continues into selective inhibitors and understanding regulation of stromelysins in disease contexts.