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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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Role of endogenous syndecan-1 in fascin spike formation by C2C12 cells adherent on TSP-1. In a separate protocol, C2C12 cotransfected with Syn-1/ΔVC2 or Syn-1/TGM and EGFP-fascin expression plasmids were identified by EGFP-fascin expression after 1 h adhesion on TSP-1. Bar, 12 μm.
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Figure 9: Role of endogenous syndecan-1 in fascin spike formation by C2C12 cells adherent on TSP-1. In a separate protocol, C2C12 cotransfected with Syn-1/ΔVC2 or Syn-1/TGM and EGFP-fascin expression plasmids were identified by EGFP-fascin expression after 1 h adhesion on TSP-1. Bar, 12 μm.

Mentions: To determine the functional role of endogenous syndecan-1 in TSP-1–initiated formation of fascin spikes in C2C12 cells, we first examined the effect of prolonged trypsinization on fascin spike organization by C2C12 cells on TSP-1. Whereas EDTA-released cells spread and formed regions of fascin spikes, <20% of cells trypsinized for 5 min attached, and these remained completely round (Fig. 9A and Fig. B). These cells lack cell surface syndecan-1 (Table ). To examine the specific role of syndecan-1, the syn-1/ΔVC2 or syn-1/TGM constructs were transiently transfected into C2C12 cells. The syn-1/ΔVC2 molecule acted as an effective dominant negative, in that, transfected cells which attached to TSP-1 did not spread or form fascin spikes (Fig. 9 C). Cells expressing the syn-1/TGM construct were altered in morphology on TSP-1, yet formed fascin projections (Fig. 9 D). Thus, in C2C12 cells as in COS-7 cells, GAG substitution of syndecan-1 is important for cell spreading on TSP-1 but does not appear to be required in fascin spike organization.


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

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

Role of endogenous syndecan-1 in fascin spike formation by C2C12 cells adherent on TSP-1. In a separate protocol, C2C12 cotransfected with Syn-1/ΔVC2 or Syn-1/TGM and EGFP-fascin expression plasmids were identified by EGFP-fascin expression after 1 h adhesion on TSP-1. Bar, 12 μm.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 9: Role of endogenous syndecan-1 in fascin spike formation by C2C12 cells adherent on TSP-1. In a separate protocol, C2C12 cotransfected with Syn-1/ΔVC2 or Syn-1/TGM and EGFP-fascin expression plasmids were identified by EGFP-fascin expression after 1 h adhesion on TSP-1. Bar, 12 μm.
Mentions: To determine the functional role of endogenous syndecan-1 in TSP-1–initiated formation of fascin spikes in C2C12 cells, we first examined the effect of prolonged trypsinization on fascin spike organization by C2C12 cells on TSP-1. Whereas EDTA-released cells spread and formed regions of fascin spikes, <20% of cells trypsinized for 5 min attached, and these remained completely round (Fig. 9A and Fig. B). These cells lack cell surface syndecan-1 (Table ). To examine the specific role of syndecan-1, the syn-1/ΔVC2 or syn-1/TGM constructs were transiently transfected into C2C12 cells. The syn-1/ΔVC2 molecule acted as an effective dominant negative, in that, transfected cells which attached to TSP-1 did not spread or form fascin spikes (Fig. 9 C). Cells expressing the syn-1/TGM construct were altered in morphology on TSP-1, yet formed fascin projections (Fig. 9 D). Thus, in C2C12 cells as in COS-7 cells, GAG substitution of syndecan-1 is important for cell spreading on TSP-1 but does not appear to be required in fascin spike organization.

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