title: Syndecan-1 expressed in Schwann cells causes morphological transformation and cytoskeletal reorganization and associates with actin during cell spreading.
abstract: To investigate the biological functions of transmembrane proteoglycans we have produced clonal cell lines of rat Schwann cells that express the hybrid proteoglycan syndecan-1. This was done by transfection of newborn rat Schwann cells with a plasmid vector bearing the rat syndecan-1 cDNA sequence under transcriptional control of the constitutively active cytomegalovirus promoter, and a neomycin resistance gene. Stably expressing cells were selected by growth in G418. Expression of syndecan-1 was verified by Northern and immunoblot analysis and immunoprecipitation of 35SO4-labeled proteoglycans. The syndecan-1 expressing cells exhibited significantly enhanced spreading on several different substrata, including fibronectin and laminin, and an altered morphology. The enhanced spreading appeared to result from the presence of syndecan-1, based on the observation that anti-syndecan-1 antibodies inhibited the enhanced substratum spreading. There was also a reorganization of cytoskeletal structures and formation of focal adhesions, visualized by anti-vinculin staining, which were absent from control Schwann cells. There was no apparent stable association of cell surface syndecan-1 with focal contact sites, as determined by dual staining with anti-syndecan-1 and anti-vinculin antibodies. Colocalization of patches of cell surface syndecan-1 with actin was observed, but only during cell spreading. These findings provide evidence for a role of transmembrane proteoglycans in cellular morphogenesis, and suggest that transient association of syndecans with microfilaments may be an important aspect of their biological function.
authors.affiliation: Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania 17822.
authors.forename: D J
authors.initials: DJ
authors.lastname: Carey
authors.forename: R C
authors.initials: RC
authors.lastname: Stahl
authors.forename: G
authors.initials: G
authors.lastname: Cizmeci-Smith
authors.forename: V K
authors.initials: VK
authors.lastname: Asundi
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002448:Cell Adhesion; D002451:Cell Compartmentation; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism*; D051381:Rats; D012583:Schwann Cells / Q000378:metabolism*; D053668:Syndecan-1; D053667:Syndecans; D014162:Transfection; D016596:Vinculin / Q000378:metabolism
chemical_list: D000199:Actins; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D011509:Proteoglycans; C508243:Sdc1 protein, rat; D053668:Syndecan-1; D053667:Syndecans; D016596:Vinculin