Soluble collagen VI induces tyrosine phosphorylation of paxillin and focal adhesion kinase and activates the MAP kinase erk2 in fibroblasts.
Signals from the extracellular matrix can modulate cellular differentiation and gene expression. We have shown previously that in contrast to other extracellular matrix molecules pepsin-solubilized collagen VI (CVI) can stimulate DNA synthesis of various mesenchymal cell types, apparently independent of integrin-mediated signal transduction. In order to further elucidate collagen VI-induced signaling events, we exposed mouse 3T3 fibroblasts and human HT1080 fibrosarcoma cells to soluble CVI. CVI induced tyrosine phosphorylation of proteins that associate with focal adhesions, such as paxillin, focal adhesion kinase (FAK), and p130CAS. Furthermore, it activated the mitogen-activated protein kinase, erk2. Kinetic analysis showed that these phosphorylations were transient, reaching a maximum after 5 min for transformed HT1080 cells and 30 min for 3T3 fibroblasts. These effects were partly inhibited by a beta1-integrin function blocking antibody and by single chains of CVI. Our results indicate that soluble fragments of native collagen VI, a ubiquitous component of the interstitial extracellular matrix, can mediate stimulation of DNA synthesis via tyrosine phosphorylation of paxillin, FAK, p130CAS, and erk2 in the absence of classical growth factors. Thus, CVI may serve as a matrix-derived sensor that allows for rapid reconstitution of a tissue defect by activating nearby mesenchymal cells.
Department of Medicine I, Klinikum B. Franklin, Free University of Berlin, Hindenburgdamm 30, Berlin, 12200, Germany.
M
M
Rühl
M
M
Johannsen
J
J
Atkinson
D
D
Manski
E
E
Sahin
R
R
Somasundaram
E O
EO
Riecken
D
D
Schuppan
D016475:3T3 Cells; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003094:Collagen / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D019012:Integrin beta1 / Q000276:immunology / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D008970:Molecular Weight; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D015398:Signal Transduction / Q000187:drug effects; D012995:Solubility; D014407:Tumor Cells, Cultured
D000906:Antibodies; C493841:BCAR1 protein, human; C493842:Bcar1 protein, mouse; D015815:Cell Adhesion Molecules; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins; D019012:Integrin beta1; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; C496062:Pxn protein, mouse; D050717:Retinoblastoma-Like Protein p130; D019000:Phosphotyrosine; D003094:Collagen; D004247:DNA; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1