title: Three-dimensional matrix induces sustained activation of ERK1/2 via Src/Ras/Raf signaling pathway.
abstract: Research in cell signaling often depends on tissue culture, but the artificial substrates used to grow cells in vitro are likely to distort the conclusions, particularly when adhesion-mediated signaling events are investigated. Studies of signal transduction pathways operating in cells grown in three-dimensional (3D) matrices provide a better system, giving a closer insight of the cell signaling in vivo. We compared the steady-state levels of ERK1/2 activity in primary human fibroblasts, induced by cell-derived 3D fibronectin matrix or fibronectin, coated on flat surfaces. 3D environment caused ERK1/2 stimulation concomitant with a 2.5-fold increase in Ras GTP loading and Src activation. Under these conditions FAK autophosphorylation was suppressed. Treatment with Src inhibitor PP2 abolished these effects indicating that 3D fibronectin matrix activated ERK1/2 through Src/Ras/Raf pathway, bypassing FAK. These observations suggest that within in vivo-like conditions Src may have a leading role in the induction of sustained ERK1/2 activation.
authors.affiliation: Department of Cytology, Histology and Embryology, Biological Faculty, Sofia University St. Kliment Ohridski, 1164 Sofia, Bulgaria.
authors.forename: Ralica
authors.initials: R
authors.lastname: Damianova
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Stefanova
authors.forename: Edna
authors.initials: E
authors.lastname: Cukierman
authors.forename: Albena
authors.initials: A
authors.lastname: Momchilova
authors.forename: Roumen
authors.initials: R
authors.lastname: Pankov
mesh_terms: D018929:Cell Culture Techniques; D048430:Cell Shape; D002478:Cells, Cultured; D004789:Enzyme Activation; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D054457:Tissue Scaffolds; D048490:raf Kinases / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases; D048490:raf Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D018631:ras Proteins