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A role for syndecan-1 in coupling fascin spike formation by thrombospondin-1.

Adams JC, Kureishy N, Taylor AL - J. Cell Biol. (2001)

Bottom Line: The underlying molecular mechanism depends on glycosaminoglycan (GAG) modification of the syndecan-1 core protein at residues S45 or S47 for cell membrane spreading and on the VC2 region of the cytoplasmic domain for spreading and fascin spike formation.Expression of the VC2 deletion mutant or GAG-negative syndecan-1 showed that syndecan-1 is necessary in spreading and fascin spike formation by C2C12 cells on TSP-1.These results establish a novel role for syndecan-1 protein in coupling a physiological matrix ligand to formation of a specific matrix contact structure.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT, United Kingdom. dmcbjca@ucl.ac.uk

ABSTRACT
An important role of cell matrix adhesion receptors is to mediate transmembrane coupling between extracellular matrix attachment, actin reorganization, and cell spreading. Thrombospondin (TSP)-1 is a modulatory component of matrix expressed during development, immune response, or wound repair. Cell adhesion to TSP-1 involves formation of biochemically distinct matrix contacts based on stable fascin spikes. The cell surface adhesion receptors required have not been identified. We report here that antibody clustering of syndecan-1 proteoglycan specifically transduces organization of cortical actin and fascin bundles in several cell types. Transfection of COS-7 cells with syndecan-1 is sufficient to stimulate cell spreading, fascin spike assembly, and extensive protrusive lateral ruffling on TSP-1 or on syndecan-1 antibody. The underlying molecular mechanism depends on glycosaminoglycan (GAG) modification of the syndecan-1 core protein at residues S45 or S47 for cell membrane spreading and on the VC2 region of the cytoplasmic domain for spreading and fascin spike formation. Expression of the VC2 deletion mutant or GAG-negative syndecan-1 showed that syndecan-1 is necessary in spreading and fascin spike formation by C2C12 cells on TSP-1. These results establish a novel role for syndecan-1 protein in coupling a physiological matrix ligand to formation of a specific matrix contact structure.

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F-actin organization in C2C12 cells adherent on adhesion receptor antibodies. Cells were plated onto surfaces, coated with 50 μg/ml of the indicated antibodies (see Materials and Methods) for 1 h in serum-free medium, then fixed and stained with TRITC-phalloidin. Bar, 15 μm.
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Figure 2: F-actin organization in C2C12 cells adherent on adhesion receptor antibodies. Cells were plated onto surfaces, coated with 50 μg/ml of the indicated antibodies (see Materials and Methods) for 1 h in serum-free medium, then fixed and stained with TRITC-phalloidin. Bar, 15 μm.

Mentions: To dissect the effects of ligation and clustering of individual TSP-1 receptors on cell attachment and actin cytoskeletal organization, the panel of antibodies reactive with the extracellular domains of mouse β1 or β3 integrin subunits, CD47, or syndecan-1 were used as adhesive substrata for C2C12 cells. All the antibodies supported quantitatively increased cell attachment relative to nonimmune rat IgG. C2C12 underwent partial spreading on the β1 integrin subunit antibody and displayed organization of F-actin at cell margins (Fig. 2 and Table ). Cells on the β3 integrin subunit antibody also spread partially and developed concentrations of F-actin at points on the cell surface (Fig. 2). On the CD47 antibody, cells spread more extensively and displayed larger actin-containing ruffles at cell margins (Fig. 2). For all these antibodies, similar results were obtained using either trypsinized or EDTA-disaggregated cells (shown in Fig. 2 for trypsinized cells only).


A role for syndecan-1 in coupling fascin spike formation by thrombospondin-1.

Adams JC, Kureishy N, Taylor AL - J. Cell Biol. (2001)

F-actin organization in C2C12 cells adherent on adhesion receptor antibodies. Cells were plated onto surfaces, coated with 50 μg/ml of the indicated antibodies (see Materials and Methods) for 1 h in serum-free medium, then fixed and stained with TRITC-phalloidin. Bar, 15 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199199&req=5

Figure 2: F-actin organization in C2C12 cells adherent on adhesion receptor antibodies. Cells were plated onto surfaces, coated with 50 μg/ml of the indicated antibodies (see Materials and Methods) for 1 h in serum-free medium, then fixed and stained with TRITC-phalloidin. Bar, 15 μm.
Mentions: To dissect the effects of ligation and clustering of individual TSP-1 receptors on cell attachment and actin cytoskeletal organization, the panel of antibodies reactive with the extracellular domains of mouse β1 or β3 integrin subunits, CD47, or syndecan-1 were used as adhesive substrata for C2C12 cells. All the antibodies supported quantitatively increased cell attachment relative to nonimmune rat IgG. C2C12 underwent partial spreading on the β1 integrin subunit antibody and displayed organization of F-actin at cell margins (Fig. 2 and Table ). Cells on the β3 integrin subunit antibody also spread partially and developed concentrations of F-actin at points on the cell surface (Fig. 2). On the CD47 antibody, cells spread more extensively and displayed larger actin-containing ruffles at cell margins (Fig. 2). For all these antibodies, similar results were obtained using either trypsinized or EDTA-disaggregated cells (shown in Fig. 2 for trypsinized cells only).

Bottom Line: The underlying molecular mechanism depends on glycosaminoglycan (GAG) modification of the syndecan-1 core protein at residues S45 or S47 for cell membrane spreading and on the VC2 region of the cytoplasmic domain for spreading and fascin spike formation.Expression of the VC2 deletion mutant or GAG-negative syndecan-1 showed that syndecan-1 is necessary in spreading and fascin spike formation by C2C12 cells on TSP-1.These results establish a novel role for syndecan-1 protein in coupling a physiological matrix ligand to formation of a specific matrix contact structure.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT, United Kingdom. dmcbjca@ucl.ac.uk

ABSTRACT
An important role of cell matrix adhesion receptors is to mediate transmembrane coupling between extracellular matrix attachment, actin reorganization, and cell spreading. Thrombospondin (TSP)-1 is a modulatory component of matrix expressed during development, immune response, or wound repair. Cell adhesion to TSP-1 involves formation of biochemically distinct matrix contacts based on stable fascin spikes. The cell surface adhesion receptors required have not been identified. We report here that antibody clustering of syndecan-1 proteoglycan specifically transduces organization of cortical actin and fascin bundles in several cell types. Transfection of COS-7 cells with syndecan-1 is sufficient to stimulate cell spreading, fascin spike assembly, and extensive protrusive lateral ruffling on TSP-1 or on syndecan-1 antibody. The underlying molecular mechanism depends on glycosaminoglycan (GAG) modification of the syndecan-1 core protein at residues S45 or S47 for cell membrane spreading and on the VC2 region of the cytoplasmic domain for spreading and fascin spike formation. Expression of the VC2 deletion mutant or GAG-negative syndecan-1 showed that syndecan-1 is necessary in spreading and fascin spike formation by C2C12 cells on TSP-1. These results establish a novel role for syndecan-1 protein in coupling a physiological matrix ligand to formation of a specific matrix contact structure.

Show MeSH
Related in: MedlinePlus