title: The fibronectin-binding integrins alpha5beta1 and alphavbeta3 differentially modulate RhoA-GTP loading, organization of cell matrix adhesions, and fibronectin fibrillogenesis.
abstract: We have studied the formation of different types of cell matrix adhesions in cells that bind to fibronectin via either alpha5beta1 or alphavbeta3. In both cases, cell adhesion to fibronectin leads to a rapid decrease in RhoA activity. However, alpha5beta1 but not alphavbeta3 supports high levels of RhoA activity at later stages of cell spreading, which are associated with a translocation of focal contacts to peripheral cell protrusions, recruitment of tensin into fibrillar adhesions, and fibronectin fibrillogenesis. Expression of an activated mutant of RhoA stimulates alphavbeta3-mediated fibrillogenesis. Despite the fact that alpha5beta1-mediated adhesion to the central cell-binding domain of fibronectin supports activation of RhoA, other regions of fibronectin are required for the development of alpha5beta1-mediated but not alphavbeta3-mediated focal contacts. Using chimeras of beta1 and beta3 subunits, we find that the extracellular domain of beta1 controls RhoA activity. By expressing both beta1 and beta3 at high levels, we show that beta1-mediated control of the levels of beta3 is important for the distribution of focal contacts. Our findings demonstrate that the pattern of fibronectin receptors expressed on a cell dictates the ability of fibronectin to stimulate RhoA-mediated organization of cell matrix adhesions.
authors.affiliation: Division of Cell Biology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands.
authors.forename: Erik H J
authors.initials: EH
authors.lastname: Danen
authors.forename: Petra
authors.initials: P
authors.lastname: Sonneveld
authors.forename: Cord
authors.initials: C
authors.lastname: Brakebusch
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fassler
authors.forename: Arnoud
authors.initials: A
authors.lastname: Sonnenberg
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D002469:Cell Separation; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005337:Fibrin / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D005434:Flow Cytometry; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020690:GTPase-Activating Proteins; D005786:Gene Expression Regulation; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism*; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins / Q000378:metabolism; D010641:Phenotype; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins; D012097:Repressor Proteins; D050717:Retinoblastoma-Like Protein p130; D000070876:Tensins; D013997:Time Factors; D014162:Transfection; D016596:Vinculin / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C074560:ARHGAP35 protein, human; D000199:Actins; C513041:Arhgap35 protein, mouse; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D005353:Fibronectins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D039081:Integrin alpha5beta1; D039302:Integrin alphaVbeta3; D016023:Integrins; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D012097:Repressor Proteins; D050717:Retinoblastoma-Like Protein p130; D000070876:Tensins; D016596:Vinculin; D006160:Guanosine Triphosphate; D005337:Fibrin; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; D020742:rhoA GTP-Binding Protein