title: MT1-MMP regulates the turnover and endocytosis of extracellular matrix fibronectin.
abstract: The extracellular matrix (ECM) is dynamically remodeled by cells during development, normal tissue homeostasis and in a variety of disease processes. We previously showed that fibronectin is an important regulator of ECM remodeling. The deposition and/or polymerization of fibronectin into the ECM controls the deposition and stability of other ECM molecules. In addition, agents that inhibit fibronectin polymerization promote the turnover of fibronectin fibrils and enhance ECM fibronectin endocytosis and intracellular degradation. Endocytosis of ECM fibronectin is regulated by β1 integrins, including α5β1 integrin. We have examined the role of extracellular proteases in regulating ECM fibronectin turnover. Our data show that membrane type matrix metalloproteinase 1 (MT1-MMP; also known as MMP14) is a crucial regulator of fibronectin turnover. Cells lacking MT1-MMP show reduced turnover and endocytosis of ECM fibronectin. MT1-MMP regulates ECM fibronectin remodeling by promoting extracellular cleavage of fibronectin and by regulating α5β1-integrin endocytosis. Our data also show that fibronectin polymerization stabilizes fibronectin fibrils and inhibits ECM fibronectin endocytosis by inhibiting α5β1-integrin endocytosis. These data are the first to show that an ECM protein and its modifying enzyme can regulate integrin endocytosis. These data also show that integrin trafficking plays a major role in modulating ECM fibronectin remodeling. The dual dependence of ECM fibronectin turnover on extracellular proteolysis and endocytosis highlights the complex regulatory mechanisms that control ECM remodeling to ensure maintenance of proper tissue function.
authors.affiliation: Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box CVRI, Rochester, NY 14642, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
authors.forename: Jane
authors.initials: J
authors.lastname: Sottile
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D004705:Endocytosis; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D005434:Flow Cytometry; D057809:HEK293 Cells; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D058628:Myofibroblasts / Q000378:metabolism; D058105:Polymerization; D055550:Protein Stability; D021381:Protein Transport; D059748:Proteolysis; D051381:Rats; D014162:Transfection; D014945:Wound Healing
chemical_list: D003470:Culture Media; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D039081:Integrin alpha5beta1; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14