Role of the hemopexin domain of matrix metalloproteinases in cell migration.
The biological functions of matrix metalloproteinases (MMPs) extend beyond extracellular matrix degradation. Non-proteolytic activities of MMPs are just beginning to be understood. Herein, we evaluated the role of proMMPs in cell migration. Employing a Transwell chamber migration assay, we demonstrated that transfection of COS-1 cells with various proMMP cDNAs resulted in enhancement of cell migration. Latent MMP-2 and MMP-9 enhanced cell migration to a greater extent than latent MMP-1, -3, -11 and -28. To examine if proteolytic activity is required for MMP-enhanced cell migration, three experimental approaches, including fluorogenic substrate degradation assay, transfection of cells with catalytically inactive mutant MMP cDNAs, and addition of hydroxamic acid-derived MMP inhibitors, were employed. We demonstrated that the proteolytic activities of MMPs are not required for MMP-induced cell migration. To explore the mechanism underlying MMP-enhanced cell migration, structure-function relationship of MMP-9 on cell migration was evaluated. By using a domain swapping approach, we demonstrated that the hemopexin domain of proMMP-9 plays an important role in cell migration when examined by a transwell chamber assay and by a phagokinetic migration assay. TIMP-1, which interacts with the hemopexin domain of proMMP-9, inhibited cell migration, whereas TIMP-2 had no effect. Employing small molecular inhibitors, MAPK and PI3K pathways were found to be involved in MMP-9-mediated cell migration. In conclusion, we demonstrated that MMPs utilize a non-proteolytic mechanism to enhance epithelial cell migration. We propose that hemopexin homodimer formation is required for the full cell migratory function of proMMP-9.
Dufour
Antoine
A
Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA.
Sampson
Nicole S
NS
Zucker
Stanley
S
Cao
Jian
J
D000818:Animals; D019556:COS Cells; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D002522:Chlorocebus aethiops; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism; D006466:Hemopexin / Q000737:chemistry*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000737:chemistry / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000737:chemistry* / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000187:drug effects; D013329:Structure-Activity Relationship; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D014162:Transfection
D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D061965:Matrix Metalloproteinase Inhibitors; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D006466:Hemopexin; D020782:Matrix Metalloproteinases; D020780:Matrix Metalloproteinase 9