title: Fibulin-1 suppression of fibronectin-regulated cell adhesion and motility.
abstract: Fibulin-1 is an extracellular matrix protein often associated with fibronectin (FN) in vivo. In this study, the ability of fibulin-1 to modulate adhesion, spreading and motility-promoting activities of FN was investigated. Fibulin-1 was found to have pronounced inhibitory effects on the cell attachment and spreading promoted by FN. Fibulin-1 was also found to inhibit the motility of a variety of cell types on FN substrata. For example, the FN-dependent haptotactic motility of breast carcinoma (MDA MB231) cells, epidermal carcinoma (A431), melanoma (A375 SM), rat pulmonary aortic smooth muscle cells (PAC1) and Chinese hamster ovary (CHO) cells was inhibited by the presence of fibulin-1 bound to FN-coated Boyden chamber membranes. Cells transfected to overproduce fibulin-1 displayed reduced velocity, distance of movement and persistence time on FN substrata. Similarly, the incorporation of fibulin-1 into FN-containing type I collagen gels inhibited the invasion of endocardial cushion mesenchymal cells migrating from cultured embryonic heart explants. By contrast, incorporation of fibulin-1 into collagen gels lacking FN had no effect on the migration of endocardial cushion cells. These results suggest that the motility-suppressive effects of fibulin-1 might be FN specific. Furthermore, such effects are cell-type specific, in that the migration of gingival fibroblasts and endothelial cells on FN substrata is not responsive to fibulin-1. Additional studies found that the mechanism for the motility-suppressive effects of fibulin-1 does not involve perturbations of interactions between alpha5beta1 or alpha4 integrins, or heparan sulfate proteoglycans with FN. However, fibulin-1 was found to inhibit extracellular signal regulated kinase (ERK) activation and to suppress phosphorylation of myosin heavy chain. This ability to influence signal transduction cascades that modulate the actin-myosin motor complex might be the basis for the effects of fibulin-1 on adhesion and motility.
authors.affiliation: Medical University of South Carolina, Department of Cell Biology, 171 Ashley Avenue, Charleston, SC 29425-2204, USA.
authors.forename: W O
authors.initials: WO
authors.lastname: Twal
authors.forename: A
authors.initials: A
authors.lastname: Czirok
authors.forename: B
authors.initials: B
authors.lastname: Hegedus
authors.forename: C
authors.initials: C
authors.lastname: Knaak
authors.forename: M R
authors.initials: MR
authors.lastname: Chintalapudi
authors.forename: H
authors.initials: H
authors.lastname: Okagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Sugi
authors.forename: W S
authors.initials: WS
authors.lastname: Argraves
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D016466:CHO Cells; D002135:Calcium-Binding Proteins / Q000502:physiology*; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002464:Cell Migration Inhibition; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D002633:Chemotaxis / Q000502:physiology; D002642:Chick Embryo; D006224:Cricetinae; D015536:Down-Regulation; D016326:Extracellular Matrix Proteins / Q000502:physiology*; D005353:Fibronectins / Q000037:antagonists & inhibitors* / Q000502:physiology*; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D039441:Integrin alpha4; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D051381:Rats; D017469:Receptors, Fibronectin / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013431:Sulfates / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D006025:Glycosaminoglycans; D017469:Receptors, Fibronectin; D013431:Sulfates; C060820:fibulin; D039441:Integrin alpha4; D000205:Actomyosin