scholarly journals Faculty Opinions recommendation of Regulation of angiogenesis in vivo by ligation of integrin alpha5beta1 with the central cell-binding domain of fibronectin.

2021 ◽  
Author(s):  
Yazmín Macotela ◽  
Juan Pablo Robles
Keyword(s):  
Binding Domain ◽  
Central Cell ◽  
Cell Binding ◽  
Integrin Alpha5beta1 ◽  
Cell Binding Domain

scholarly journals Neurite extension of chicken peripheral nervous system neurons on fibronectin: relative importance of specific adhesion sites in the central cell-binding domain and the alternatively spliced type III connecting segment.

1988 ◽  
Vol 106 (4) ◽  
pp. 1289-1297 ◽  
Author(s):  
M J Humphries ◽  
S K Akiyama ◽  
A Komoriya ◽  
K Olden ◽  
K M Yamada
Keyword(s):  
Nervous System ◽  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Peripheral Nervous System ◽  
Binding Domain ◽  
Central Cell ◽  
Cell Binding ◽  
Alternatively Spliced ◽  
Cell Binding Domain ◽  
Iiics Region

Fibronectin contains at least two domains that support cell adhesion. One is the central cell-binding domain that is recognized by a variety of cell types, including fibroblasts. The second, originally identified by its ability to support melanoma cell adhesion, is located in the alternatively spliced type III connecting segment (IIICS). Using specific adhesive ligands and inhibitory probes, we have examined the role of each of these domains in fibronectin-mediated neurite extension of neurons from chick embryo dorsal root and sympathetic ganglia. In studies using explanted ganglia, both fl3, a 75-kD tryptic fragment of human plasma fibronectin containing the central cell-binding domain, and CS1-IgG, a synthetic peptide-IgG conjugate containing the principal cell adhesion site from the IIICS, supported neurite outgrowth after adsorption onto the substrate. The maximal activities of fl3 and CSl-IgG were 45-55% and 25-30% that of intact fibronectin, respectively. Co-coating of the substrate with f13 and CS1-IgG produced an additive stimulation of neurite outgrowth, the extent of which approached that obtained with fibronectin. Similar results were obtained with purified neuronal cell preparations isolated by tryptic dissociation of dorsal root ganglia. In complementary studies, blockage of the adhesive function of either the central cell-binding domain (with mAb 333, an antiadhesive monoclonal antibody) or the IIICS (with CS1 peptide), resulted in approximately 60 or 30% reduction in fibronectin-mediated neurite outgrowth, respectively. When tested in combination, the inhibitory activities of mAb 333 and CSl were additive. From these results, we conclude that neurons from the peripheral nervous system can extend neurites on both the central cell-binding domain and the IIICS region of fibronectin, and that these cells are therefore the first normal, embryonic cell type shown to adhere to the IIICS. These results suggest that spatiotemporal fluctuations in the alternative mRNA splicing of the IIICS region of fibronectin may be important in regulation of cell adhesive events during development of the peripheral nervous system.

scholarly journals Monoclonal antibody characterization of two distant sites required for function of the central cell-binding domain of fibronectin in cell adhesion, cell migration, and matrix assembly.

1991 ◽  
Vol 114 (6) ◽  
pp. 1295-1305 ◽  
Author(s):  
T Nagai ◽  
N Yamakawa ◽  
S Aota ◽  
S S Yamada ◽  
S K Akiyama ◽  
...  
Keyword(s):  
Cell Spreading ◽  
Binding Domain ◽  
Central Cell ◽  
Site Directed Mutagenesis ◽  
Cell Binding ◽  
Matrix Assembly ◽  
Fibronectin Receptor ◽  
Molar Basis ◽  
Rgd Site ◽  
Cell Binding Domain

Site-directed mutagenesis studies have suggested that additional peptide information in the central cell-binding domain of fibronectin besides the minimal Arg-Gly-Asp (RGD) sequence is required for its full adhesive activity. The nature of this second, synergistic site was analyzed further by protein chemical and immunological approaches using biological assays for adhesion, migration, and matrix assembly. Fragments derived from the cell-binding domain were coupled covalently to plates, and their specific molar activities in mediating BHK cell spreading were compared with that of intact fibronectin. A 37-kD fragment purified from chymotryptic digests of human plasma fibronectin had essentially the same specific molar activity as intact fibronectin. In contrast, other fragments such as an 11.5-kD fragment lacking NH2-terminal sequences of the 37-kD fragment had only poor spreading activity on a molar basis. Furthermore, in competitive inhibition assays of fibronectin-mediated cell spreading, the 37-kD fragment was approximately 325-fold more active than the GRGDS synthetic peptide on a molar basis. mAbs were produced using the 37-kD protein as an immunogen and their epitopes were characterized. Two separate mAbs, one binding close to the RGD site and the other to a site approximately 15 kD distant from the RGD site, individually inhibited BHK cell spreading on fibronectin by greater than 90%. In contrast, an antibody that bound between these two sites had minimal inhibitory activity. The antibodies found to be inhibitory in cell spreading assays for BHK cells also inhibited both fibronectin-mediated cell spreading and migration of human HT-1080 cells, functions which were also dependent on function of the alpha 5 beta 1 integrin (fibronectin receptor). Assembly of endogenously synthesized fibronectin into an extracellular matrix was not significantly inhibited by most of the anti-37-kD mAbs, but was strongly inhibited only by the antibodies binding close to the RGD site or the putative synergy site. These results indicate that a second site distant from the RGD site on fibronectin is crucial for its full biological activity in diverse functions dependent on the alpha 5 beta 1 fibronectin receptor. This site is mapped by mAbs closer to the RGD site than previously expected.

Controlled release of the fibronectin central cell binding domain from polymeric microspheres

2004 ◽  
Vol 95 (3) ◽  
pp. 557-566 ◽  
Author(s):  
Camille Bouissou ◽  
Ursula Potter ◽  
Harri Altroff ◽  
Helen Mardon ◽  
Christopher van der Walle
Keyword(s):  
Controlled Release ◽  
Binding Domain ◽  
Central Cell ◽  
Cell Binding ◽  
Polymeric Microspheres ◽  
Cell Binding Domain

scholarly journals Fine mapping of inhibitory anti-α5 monoclonal antibody epitopes that differentially affect integrin–ligand binding

1999 ◽  
Vol 344 (2) ◽  
pp. 527-533 ◽  
Author(s):  
Louise BURROWS ◽  
Katherine CLARK ◽  
A. Paul MOULD ◽  
Martin J. HUMPHRIES
Keyword(s):  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Binding Domain ◽  
Central Cell ◽  
Subunit Structure ◽  
Cell Binding ◽  
Α Subunit ◽  
Type Iii ◽  
Integrin Ligand ◽  
Cell Binding Domain

The high-affinity interaction of integrin α5β1 with the central cell-binding domain of fibronectin requires both the Arg-Gly-Asp (RGD) sequence (in the tenth type III repeat) and a second site Pro-His-Ser-Arg-Asn (PHSRN) in the adjacent ninth type III repeat, which synergizes with RGD. Arg-Arg-Glu-Thr-Ala-Trp-Ala (RRETAWA) is a novel peptidic ligand for α5β1, identified by phage display, which blocks α5β1-mediated cell adhesion to fibronectin. A key question is the location of the binding sites for these ligand sequences within the integrin. In this study we have identified residues that form part of the epitopes of three inhibitory anti-α5 monoclonal antibodies (mAbs): 16, P1D6 and SNAKA52. These mAbs have distinct functional properties. mAb 16 blocks the recognition of RGD and RRETAWA, whereas P1D6 blocks binding to the synergy sequence. The binding of SNAKA52 is inhibited by anti-β1 mAbs, indicating that its epitope is close to the interface between the α and β subunits. Residues in human α5 were replaced with the corresponding residues in mouse α5 by site-directed mutagenesis; wild-type or mutant human α5 was expressed on the surface of α5-deficient Chinese hamster ovary cells. mAb binding was assessed by flow cytometry and by adhesion to the central cell-binding domain of fibronectin or RRETAWA by cell attachment assay. All three epitopes were located to different putative loops in the N-terminal domain of α5. As expected, disruption of these epitopes had no effect on ligand recognition by α5β1. The locations of these epitopes are consistent with the β-propeller model for integrin α-subunit structure and allow us to propose a topological image of the integrin-ligand complex.

scholarly journals Integrin-dependent adhesive activity is spatially controlled by inductive signals at gastrulation

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2873-2883 ◽  
Author(s):  
J.W. Ramos ◽  
C.A. Whittaker ◽  
D.W. DeSimone
Keyword(s):  
Cell Adhesion ◽  
Ectopic Expression ◽  
Binding Domain ◽  
Central Cell ◽  
Receptor Expression ◽  
General Mechanism ◽  
Cell Binding ◽  
V Region ◽  
Cell Binding Domain ◽  
Inductive Signals

Integrins mediate cell-ECM interactions essential for morphogenesis, however, the extent to which integrin adhesive activities are regulated in the embryo has not been addressed. We report that integrin-dependent cell adhesion to the Arg-Gly-Asp (RGD) containing central cell-binding domain of fibronectin is required for gastrulation in Xenopus. Although all cells of the early embryo retain the ability to attach to this region, only involuting cells arising from the dorsal and ventral lips of the blastopore are able to spread and migrate on fibronectin in vitro. This change in adhesive behavior is mimicked by treating animal cap cells with activin-A. Activin-induced changes in adhesion are independent of new transcription, translation, or changes in receptor expression at the cell surface. We demonstrate that ectopic expression of integrin alpha4beta1 in animal cap cells results in attachment to the non RGD-containing V-region of fibronectin. Further, these cells acquire the ability to spread on the V-region following activin induction. Thus, alpha4beta1 adhesion to the V-region, like endogenous integrin binding to the central cell-binding domain, is responsive to activin signalling. These data indicate that cell adhesion to the central cell-binding domain is regulated in both space and time, and is under the control of inductive signals that initiate gastrulation movements. We suggest that position-specific inductive interactions are likely to represent a novel and general mechanism by which integrin adhesion is modulated throughout development.

scholarly journals Fibronectin regulates calvarial osteoblast differentiation

1996 ◽  
Vol 109 (6) ◽  
pp. 1369-1380 ◽  
Author(s):  
A.M. Moursi ◽  
C.H. Damsky ◽  
J. Lull ◽  
D. Zimmerman ◽  
S.B. Doty ◽  
...  
Keyword(s):  
Osteoblast Differentiation ◽  
Binding Domain ◽  
Central Cell ◽  
Nodule Formation ◽  
Cell Binding ◽  
Rgd Sequence ◽  
Fetal Rat ◽  
Fibronectin Fragments ◽  
Nodule Initiation ◽  
Cell Binding Domain

The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of alpha 5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6–10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression.

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