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Lookup NU author(s): Dr Vasileia Sapountzi
Cell protrusions contribute to cell motility and migration by mediating the outward extension and initial adhesion of cell edges. In many cells, these extensions are supported by actin bundles assembled by the actin cross-linking protein, fascin. Multiple extracellular cues regulate fascin and here we focus on the mechanism by which the transmembrane proteoglycan, syndecan-1, specifically activates lamellipodial cell spreading and fascin-and-actin bundling when clustered either by thrombospondin-1, laminin, or antibody to the syndecan-1 extracellular domain. There is almost no knowledge of the signaling mechanisms of syndecan-1 cytoplasmic domain and we have tested the hypothesis that the unique V region of syndecan-1 cytoplasmic domain has a crucial role in these processes. By four criteria-the activities of N-cadherin/V region chimeras, syndecan-1 deletion mutants, or syndecan-1 point mutants, and specific inhibition by a membrane-permeable TAT-V peptide-we demonstrate that the V region is necessary and sufficient for these cell behaviors and map the molecular basis for its activity to multiple residues located across the V region. These activities correlate with a V-region-dependent incorporation of cell-surface syndecan-1 into a detergent-insoluble form. We also demonstrate functional roles of syndecan-1 V region in laminin-dependent C2C12 cell adhesion and three-dimensional cell migration. These data identify for the first time specific cell behaviors that depend on signaling through the V region of syndecan-1. © 2005 by The American Society for Cell Biology.
Author(s): Chakravarti R, Sapountzi V, Adams JC
Publication type: Article
Publication status: Published
Journal: Molecular Biology of the Cell
Year: 2005
Volume: 16
Issue: 8
Pages: 3678-3691
Print publication date: 01/08/2005
Date deposited: 20/09/2010
ISSN (print): 1059-1524
ISSN (electronic): 1939-4586
Publisher: American Society for Cell Biology
URL: http://dx.doi.org/10.1091/mbc.E04-10-0907
DOI: 10.1091/mbc.E04-10-0907
PubMed id: 15930135
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