1. Integrin cleavage facilitates cell surface-associated proteolysis required for vascular smooth muscle cell invasion
- Author
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Dietger Stibenz, Vesna Furundzija, Heike Meyborg, Kai Kappert, Jan Kaufmann, Philipp Stawowy, Bernadette Baumann, Eckart Fleck, and Kristof Graf
- Subjects
Integrins ,Proteolysis ,Myocytes, Smooth Muscle ,Integrin ,Cell ,Biochemistry ,Collagen Type I ,Muscle, Smooth, Vascular ,Rats, Sprague-Dawley ,Cell membrane ,Cell Movement ,Concanavalin A ,Matrix Metalloproteinase 14 ,medicine ,Animals ,Humans ,Furin ,Enzyme Precursors ,Integrin alphaVbeta3 ,medicine.diagnostic_test ,biology ,Chemistry ,Cell Membrane ,Cell Biology ,Flow Cytometry ,Proprotein convertase ,Rats ,Cell biology ,Drug Combinations ,medicine.anatomical_structure ,embryonic structures ,Integrin alphaV ,biology.protein ,Gelatin ,Proteoglycans ,Collagen ,Laminin ,Protein Processing, Post-Translational - Abstract
Vascular smooth muscle cell (VSMC) invasion is a key element in atherogenesis and restenosis, requiring integrins for adhesion/de-adhesion as well as matrix metalloproteinases (MMPs) for focalized proteolysis. Among the MMP family, pro-MMP-2 is unique in its activation, depending on the formation of a multiprotein complex with MT1-MMP/TIMP-2 at the cell surface, in which integrin alphavbeta3 participates. Integrin alphav and MT1-MMP are synthesized from precursors via furin-dependent cleavage of their pro-peptide. Furin is the prototypical proprotein convertase highly expressed in VSMCs and human atherosclerotic lesions. Its precise role in the tight network involving MMPs/integrins and their coordination and cooperation required for VSMC invasion is unknown. We demonstrate that furin-inhibition with decanoyl-RVKR-chloromethylketone inhibits VSMC invasion in a comparable degree to MMP inhibitors, which reduce the MT1-MMP-MMP-2 proteolytic cascade. Furin-inhibition did not prevent MT1-MMP/MMP-2 maturation. In contrast, it strongly reduced pro-alphav cleavage, but did not lessen its cell membrane expression. However, inhibition of pro-alphav processing via furin-inhibition strongly reduced pro-MMP-2 binding to the cell surface, thereby lessening its full maturation and diminishing the cell surface in situ proteolysis required for invasion. Thus, our data demonstrate a novel mechanism of furin-dependent alphav cleavage that enhances pro-MMP-2 binding and activation at the cell membrane in cooperation with MT1-MMP in primary VSMCs. Processing of alphav by furin contributes to the recruitment of enzymatic energy to the cell surface, thereby providing focalized proteolysis associated with VSMC invasion.
- Published
- 2009
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