Evidence that binding to the carboxyl-terminal heparin-binding domain (Hep II) dominates the interaction between plasma fibronectin and heparin

Biochemistry ◽  
1988 ◽  
Vol 27 (19) ◽  
pp. 7565-7571 ◽  
Author(s):  
Michael J. Benecky ◽  
Carl G. Kolvenbach ◽  
David L. Amrani ◽  
Michael W. Mosesson
1996 ◽  
Vol 317 (3) ◽  
pp. 871-877 ◽  
Author(s):  
Andrew WALKER ◽  
John T. GALLAGHER

Heparan sulphate (HS) is an abundant polysaccharide component of the pericellular domain and is found in most soft tissues and all adherent cells in culture. It interacts with a wide spectrum of proteins including polypeptide growth factors and glycoproteins of the extracellular matrix. These interactions might influence fundamental cellular activities such as adhesion, growth and migration. HS might therefore represent a highly adaptive mechanism by which cells respond to their environment. The present study shows that the interaction between fibroblast HS, metabolically labelled with [3H]glucosamine, and the C-terminal heparin-binding domain of human plasma fibronectin (HEPII), is determined by distinct regions of the polysaccharide chain. By using a very sensitive affinity-chromatography method and specific polysaccharide scission it was shown that the HEPII-binding regions of HS reside within sulphated domains that are resistant to degradation by heparinase III. In addition, optimal binding was achieved with specific heparinase III-resistant fragments of 14–16 monosaccharides in length. The affinity of HS for HEPII was significantly decreased when the polysaccharide was cleaved with heparinase I. Chondroitin sulphate and dermatan sulphate were poor competitive inhibitors of [3H]HS binding to HEPII whereas unlabelled HS and heparin gave a strong inhibitory activity, with heparin being the most potent inhibitor. These findings suggest that the interaction between HEPII and HS is specific and requires extended sequences of seven to eight N-sulphated disaccharides in which a proportion of the iduronate residues are sulphated at C-2. The results have important implications for the functions of HS in cell adhesion and migration.


1987 ◽  
Vol 104 (1) ◽  
pp. 131-139 ◽  
Author(s):  
D D Roberts ◽  
J A Sherwood ◽  
V Ginsburg

Human platelet thrombospondin adsorbed on plastic promotes attachment and spreading of human G361 melanoma cells. Attachment is rapid, and spreading is maximal by 90 min with 60-90% of the attached cells spread. In contrast, thrombospondin promotes attachment but not spreading of human C32 melanoma cells, which attach and spread only on laminin substrates. The specificity of these interactions and the regions of the thrombospondin molecule involved in attachment and spreading were examined using proteolytic fragments of thrombospondin and by inhibition studies. The sulfated fucan, fucoidan, and monoclonal antibody A2.5, which is directed against the heparin-binding domain of thrombospondin, selectively inhibit spreading but only weakly inhibit attachment. Monoclonal antibodies against some other domains of thrombospondin, however, are potent inhibitors of attachment. The amino-terminal heparin-binding domain of thrombospondin does not promote attachment. Large fragments lacking the heparin-binding domain support attachment but not spreading of G361 cells. Attachment activity is lost following removal of the 18-kD carboxyl-terminal domain. These results suggest that at least two melanoma ligands are involved in cell attachment and spreading on thrombospondin. The carboxyl-terminal region and perhaps other regions of the molecule bind to receptor(s) on the melanoma surface that promote initial attachment but not cell spreading. Interaction of the heparin-binding domain with sulfated glycoconjugates on melanoma surface proteoglycans and/or sulfated glycolipids mediates spreading. Monoclonal antibodies A2.5 and C6.7 also reverse spreading of G361 cells growing on glass culture substrates, suggesting that binding to thrombospondin mediates attachment of these melanoma cells in culture.


1994 ◽  
Vol 152 (4) ◽  
pp. 1275-1280 ◽  
Author(s):  
David Li-Wei Cheng ◽  
Wei-Ping Shu ◽  
Jimmy C.S. Choi ◽  
Eric J. Margolis ◽  
Michael J. Droller ◽  
...  

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