Matrix metalloproteinase 19 regulates insulin-like growth factor-mediated proliferation, migration, and adhesion in human keratinocytes through proteolysis of insulin-like growth factor binding protein-3.
Unlike most other matrix metalloproteinases (MMPs) MMP-19 is expressed in undifferentiated basal keratinocytes of healthy human skin. The human keratinocyte cell line HaCaT, which like basal keratinocytes constitutively expresses MMP-19, down-regulated the expression of MMP-19 at high calcium concentrations. Calcium-regulation occurred through E-cadherin mediated cell-cell contacts because neutralizing anti-E-cadherin antibodies restored MMP-19 expression in high calcium. Overexpression of MMP-19 in HaCaT cells (HaCaT-WT) increased cellular proliferation, as well as migration and adhesion on type I collagen. This was due to proteolysis of the insulin-like growth factor (IGF) binding protein-3 by MMP-19, which augmented signaling through the IGF-I receptor, as evidenced by its increased autophosphorylation. Conversely, these effects were not observed in cells transfected with MMP-2 or a catalytically inactive MMP-19 mutant. As further proof that increased IGF-signaling promoted adhesion and migration in HaCaT-WT cells, we reproduced these effects by treating parental HaCaT with IGF-I. We observed dephosphorylation of the focal adhesion kinase in HaCaT-WT as well as IGF-I-treated HaCaT cells, suggesting that inactivating focal adhesion kinase is a mechanism by which IGF-I enhances adhesion. Furthermore, IGF-I-triggered motility on type I collagen was mediated by MMP activity, which, however, was distinct from MMP-19. Considering the coexpression of IGFBP-3 and MMP-19 in the skin, we conclude that MMP-19 is a likely candidate to be the major IGFBP-3 degrading MMP in the quiescent epidermis. This activity might have widespread consequences for the behavior of epidermal keratinocytes.
Sadowski
Thorsten
T
Institute of Biochemistry, Christian-Albrechts-University of Kiel, D-24118 Kiel, Germany.
Dietrich
Sebastian
S
Koschinsky
Felix
F
Sedlacek
Radislav
R
D015820:Cadherins / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion; D002454:Cell Differentiation; D002455:Cell Division; D002465:Cell Movement; D002478:Cells, Cultured; D003001:Cloning, Molecular; D024042:Collagen Type I / Q000378:metabolism / Q000502:physiology; D015536:Down-Regulation; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D007150:Immunohistochemistry; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism* / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000502:physiology; D015603:Keratinocytes / Q000201:enzymology* / Q000502:physiology; D053505:Matrix Metalloproteinases, Secreted; D008666:Metalloendopeptidases / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism / Q000502:physiology; D017526:Receptor, IGF Type 1 / Q000378:metabolism* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000201:enzymology / Q000503:physiopathology
D015820:Cadherins; D024042:Collagen Type I; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D011505:Protein-Tyrosine Kinases; D017526:Receptor, IGF Type 1; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D053505:Matrix Metalloproteinases, Secreted; D008666:Metalloendopeptidases; C108362:matrix metalloproteinase 19; D002118:Calcium