Cell adhesion is a process which is initiated by the attachment of cells to specific sites in adhesive matrix proteins via cell surface receptors of the integrin family. This is followed by a reorganization of cytoskeletal elements which results in cell spreading and the formation of focal adhesion plaques. We have examined the effects of a class of small galactosaminoglycan-containing proteoglycans on the various stages of cell adhesion to fibronectin-coated substrates. Our results indicate that dermatan sulfate proteoglycans (DSPGs) derived from cartilage, as well as other related small proteoglycans, inhibit the initial attachment of CHO cells and rat embryo fibroblasts to substrates composed of the 105-kD cell-binding fibronectin fragment, but do not affect cell attachment to intact fibronectin. Although this effect involves binding of DSPGs to the substrate via the protein core, the intact proteoglycan is necessary for the observed activity. Isolated core proteins are inactive. The structural composition of the galactosaminoglycan chain does not appear to be functionally significant since both chondroitin sulfate and various dermatan sulfate proteoglycans of this family inhibit cell attachment to the fibronectin fragment. Neither the percentage of cells spread nor the mean area of spread cells adhering to substrates of intact fibronectin was significantly affected by the DSPGs. However, significantly fewer cells formed focal adhesions in the presence of DSPGs as compared with untreated control cells. These results suggest that the binding of small galactosaminoglycan-containing proteoglycans to a fibronectin substrate may affect several stages in the cell adhesion process.
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September 15 1992
Regulation of cell substrate adhesion: effects of small galactosaminoglycan-containing proteoglycans.
D J Bidanset,
D J Bidanset
Department of Cell Biology, University of Alabama at Birmingham 35294.
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R LeBaron,
R LeBaron
Department of Cell Biology, University of Alabama at Birmingham 35294.
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L Rosenberg,
L Rosenberg
Department of Cell Biology, University of Alabama at Birmingham 35294.
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J E Murphy-Ullrich,
J E Murphy-Ullrich
Department of Cell Biology, University of Alabama at Birmingham 35294.
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M Hook
M Hook
Department of Cell Biology, University of Alabama at Birmingham 35294.
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D J Bidanset
Department of Cell Biology, University of Alabama at Birmingham 35294.
R LeBaron
Department of Cell Biology, University of Alabama at Birmingham 35294.
L Rosenberg
Department of Cell Biology, University of Alabama at Birmingham 35294.
J E Murphy-Ullrich
Department of Cell Biology, University of Alabama at Birmingham 35294.
M Hook
Department of Cell Biology, University of Alabama at Birmingham 35294.
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1992) 118 (6): 1523–1531.
Citation
D J Bidanset, R LeBaron, L Rosenberg, J E Murphy-Ullrich, M Hook; Regulation of cell substrate adhesion: effects of small galactosaminoglycan-containing proteoglycans.. J Cell Biol 15 September 1992; 118 (6): 1523–1531. doi: https://doi.org/10.1083/jcb.118.6.1523
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