Fibronectin and vitronectin regulate the organization of their respective Arg-Gly-Asp adhesion receptors in cultured human endothelial cells.

Dejana, Elisabetta; Colella, S; Conforti, G; Abbadini, Marzia; Gáboli, Mirella; Marchisio, P. C.

doi:10.1083/jcb.107.3.1215

Cited by 243 publications

(131 citation statements)

References 34 publications

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“…For instance, fibronectin and vitronectin have been proposed to organize and cluster preexposed receptor molecules freely moving within the plane of the membrane of endothelial cells in the correspondence of adhesion plaques [21]. Furthermore, in a recent study, Bowditch et al [22] have shown the importance of sequences in fibronectin other than the RGD tripeptide main site that interact with integrin aabj3.…”

Section: Discussionmentioning

confidence: 99%

Multiple binding sites in fibronectin and the staphylococcal fibronectin receptor

Bozzini

Visai

Pignatti

et al. 1992

European Journal of Biochemistry

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The binding of fibronectin to Staphylococci exhibits the properties of a ligand-receptor interaction and has been proposed to mediate bacterial adherence to host tissues.To localize staphylococcal-binding sites in fibronectin, the protein was subjected to limited proteolysis and, of the generated fragments, Staphylococci appeared to preferentially bind to the N-terminal fragment. Different fibronectin fragments were isolated and tested for their ability to inhibit lZ5I-fibronectin binding to Staphylococci. The results indicate that only the N-terminal region effectively competed for fibronectin binding. However, when isolated fragments were adsorbed to microtiter wells, we found that two distinct domains, corresponding to the N-terminal fragment and to the heparin-binding peptide mapping close to the C-terminal end of fibronectin, promoted the attachment of both Staphylococcus aureus Newman and coagulase-negative strain of Staphylococcus capitis 651.These same domains were recognized by purified '251-labeled staphylococcal receptor, either when immobilized on microtiter wells or probed after adsorbtion onto nitrocellulose membrane.The heparin-binding domain is comprised of type-111-homology repeats 14, 15 and 16. To determine which repeats participate in this interaction, we isolated and tested repeats type IIII4 and type IIII6. We found that the major staphylococcal-binding site is located in repeat type III14.The staphylococcal receptor bound the N-terminal domain of fibronectin with a KD of 1.8 nM, whereas the dissociation constant of the receptor molecule for the internal heparin-binding domain was 10 nM.Since the fusion protein ZZ-FR, which contains the active sequences of fibronectin receptor (Dl-D3) bound only to the N-terminus, it is reasonable to assume that the bacterial receptor may have additional binding sites outside the D domains, capable of interacting with the internal heparinbinding domain of fibronectin.Fibronectin is a large dimeric glycoprotein found in body fluids, present in a fibrillar form in the extracellular matrix of loose connective tissue.Fibronectin contains a number of discrete functional domains capable of independent binding to ligands such as collagens, glycosaminoglycans, fibrin(ogen) and thrombospondin. Fibronectin also mediates adhesion of various cell lines through the RGD sequence, located in the central part of the protein. The RGD sequence within fibronectin has been shown to interact with cell-surface glycoproteins, termed integrins, which are a family of structurally related heterodimers. Moreover, the internal heparin-binding domain can also promote cell adhesion by an RGD-independent mechanism. This adhesion can be inhibited by heparin and it is likely that this domain of fibronectin interacts with cellsurface heparan sulfate proteoglycans 111.Several pathogenic Gram-positive bacteria bind fibronectin through a specific receptor and it has been suggested that this binding may serve as a mechanism of tissue adherence [2]. The primary binding site for Staphylococci [3],

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Section: Discussionmentioning

confidence: 99%

Multiple binding sites in fibronectin and the staphylococcal fibronectin receptor

Bozzini

Visai

Pignatti

et al. 1992

European Journal of Biochemistry

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“…FN contains several discrete domains that are involved in the binding to cell surfaces, including the C-terminal Hep II domain, 17,18 the alternatively spliced type III connecting segment, 19 and the central cell-binding domain. 20 EC adhesion to FN is primarily mediated by ␣5␤1, 21 but also by proteoglycans on the cell surface. A chondroitin sulfate proteoglycan with weak affinity for FN reduced binding of FN to both cells and the purified FN receptor (␣5␤1), probably by steric hindrance.…”

Section: Discussionmentioning

confidence: 99%

Increased Angiogenic Response in Aortic Explants of Collagen XVIII/Endostatin-Null Mice

Olsen

2004

The American Journal of Pathology

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Endostatin, a proteolytic fragment of basement membrane-associated collagen XVIII, has been shown to be a potent angiogenesis inhibitor both in vivo and in vitro when given at high concentrations. The precise molecular mechanisms by which it functions and whether or not it plays a role in physiological regulation of angiogenesis are not clear. In mice with targeted null alleles of Col18a1, there appears to be no major abnormality in vascular patterns or capillary density in most organs. Furthermore, the growth of experimental tumors is not increased. However, a detailed analysis of induced angiogenesis in these mice has not been performed. Therefore, we compared the angiogenic responses induced by in vitro culture of aortic explants from collagen XVIII/endostatin-null mice (ko) to wild-type (wt) littermates. We found a twofold increase in microvessel outgrowth in explants from ko mice, relative to wt explants. This increased angiogenesis was reduced to the wt level by the addition of low levels (0.1 g/ml) of recombinant mouse or human endostatin during the culture period. To address cellular/molecular mechanisms underlying this difference in angiogenic response between ko and wt mice, we isolated endothelial cells from both strains and compared their biological behavior. Proliferation assays showed no difference between the two types of endothelial cells. In contrast, adhesion assays showed a striking difference in their ability to adhere to fibronectin suggesting that collagen XVIII/endostatin may regulate interactions between endothelial cells and underlying basement membraneassociated components, including fibronectin, such that in the absence of collagen XVIII/endostatin, endothelial cells are more adhesive to fibronectin. In the aortic explant assay, characterized by dynamic processes of microvessel elongation and regression, this may result in stabilization of newly formed vessels, reduced regression, and a net increase in microvessel outgrowth in explants from ko mice compared to the wt littermates. Collagen XVIII is a heparan sulfate-containing collagen and proteoglycan that is located in the basement membranes (BMs) of epithelia and vascular endothelium. Endostatin (ES), a proteolytic fragment of the C-terminal nontriple-helical (NC1) domain of collagen XVIII, has been identified as a potent angiogenesis inhibitor.1 Recombinant ES has been reported to inhibit endothelial cell proliferation 1 and migration 2 and to induce endothelial cell apoptosis, 3,4 but it is unclear whether ES functions as a physiological regulator of angiogenesis. To gain insights into the potential physiological role of collagen XVIII/ES as a local regulator of angiogenesis, we generated Col18a1-null mice by gene targeting. Surprisingly, the mice were fertile and had a normal life span. Histological studies of embryos and adult mice have shown ocular abnormalities, including 1) delayed hyaloid vessel regression and abnormal outgrowth of the retinal vasculature;5 2) developmental defects in the iris characterized by rupture of the ...

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“…It is clear that there is remarkable specificity in recruitment of integrins to focal adhesions (11,12). This specificity was manifest in these experiments by the failure of Ottrd33 to enter focal adhesions formed during adhesion to fibronectin.…”

Section: Discussionmentioning

confidence: 99%

Distinct functions of integrin alpha and beta subunit cytoplasmic domains in cell spreading and formation of focal adhesions

Ylänne

Chen

O’Toole

et al. 1993

The Journal of Cell Biology

217

158

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Abstract. Integrin-mediated cell adhesion often results in cell spreading and the formation of focal adhesions. We exploited the capacity of recombinant human o~/~3 integrin to endow heterologous cells with the ability to adhere and spread on fibrinogen to study the role of integrin cytoplasmic domains in initiation of cell spreading and focal adhesions. The same constructs were also used to analyze the role of the cytoplasmic domains in maintenance of the fidelity of the integrin repertoire at focal adhesions. Truncation mutants of the cytoplasmic domain of oe~ did not interfere with the ability of Ottr~3 to initiate cell spreading and form focal adhesions. Nevertheless, deletion of the tXnb cytoplasmic domain allowed indiscriminate recruitment of O~m~3 to focal adhesions formed by other integrins. Truncation of the/33 subunit cytoplasmic domain abolished cell spreading mediated by o~m/~3 and also abrogated recruitment of c~m,/~3 to focal adhesions. This truncation also dramatically impaired the ability of O~nb/~3 to mediate the contraction of fibrin gels. In contrast, the/33 subunit cytoplasmic truncation did not reduce the fibrinogen binding affinity of t~m~3. Thus, the integrin/~3 subunit cytoplasmic domain is necessary and sufficient for initiation of cell spreading and focal adhesion formation. Further, the/33 cytoplasmic domain is required for the transmission of intraceUular contractile forces to fibrin gels. The o~ subunit cytoplasmic domain maintains the fidelity of recruitment of the integrins to focal adhesions and thus regulates their repertoire of integrins. C ELL adhesion is controlled by binding affinity and kinetics of interaction between adhesive ligands and cell surface receptors. In addition, events such as lateral diffusion of receptors (7) and interactions with and reorganization of the cytoskeleton strengthen adhesion (16,29). Cell adhesion induces changes of cell shape and cytoskeietai organization and regulates cell growth and patterns of gene expression (24,48,53). Integrins are transmembrane heterodimeric glycoprotein adhesion receptors present in almost all ceils (23). These receptors mediate all of the consequences of cell adhesion enumerated above. Moreover, after initial cell adhesion, many integrins are concentrated at sites of close approximation between cell and substrate. These sites, termed focal adhesions or focal contacts (4), are also sites of end-on insertion of actin microfilaments into the plasma membrane and at which certain cytoskeletal and signaling molecules concentrate (53). Ligand binding to many integrins triggers focal adhesion formarion. In addition to initiating focal adhesions, certain mutant integrins (58) or receptor chimeras containing the El cytoplasmic domain (27, 49) are recruited to existing focal adhesions without evident ligand binding. Thus, analysis of the role of integrins in formation of focal adhesions may be divided into initiation and recruitment functions. Integrin cytoplasmic domains are topographically accessible to intracellular cytoplasmic...

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Fibronectin and vitronectin regulate the organization of their respective Arg-Gly-Asp adhesion receptors in cultured human endothelial cells.

Cited by 243 publications

References 34 publications

Multiple binding sites in fibronectin and the staphylococcal fibronectin receptor

Multiple binding sites in fibronectin and the staphylococcal fibronectin receptor

Increased Angiogenic Response in Aortic Explants of Collagen XVIII/Endostatin-Null Mice

Distinct functions of integrin alpha and beta subunit cytoplasmic domains in cell spreading and formation of focal adhesions

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