title: Syndecan-1 interaction with the LG4/5 domain in laminin-332 is essential for keratinocyte migration.
abstract: Laminin 5/laminin 332 (LN332) is an adhesion substrate for epithelial cells. After secretion of LN332, a regulated cleavage occurs at the carboxy-terminus of its alpha3 subunit, which releases a tandem of two globular modules named LG4/5. We show that the presence of the LG4/5 domain in precursor LN332 decreases its integrin-mediated cell adhesion properties in comparison with mature LN332. Whereas cell adhesion to the recombinant LG4/5 fragment relies solely on the heparan sulfate proteoglycan (HSPG) receptor syndecan-1, we reveal that both syndecan-1 and the alpha3beta1 integrin bind to precursor LN332. We further demonstrate that syndecan-1 mediated cell adhesion to the LG4/5 fragment and pre-LN332 allows the formation of fascin-containing protrusions, depending on the GTPases Rac and Cdc42 activation. Reducing syndecan-1 expression in normal keratinocytes prevents cell protrusions on pre-LN332 with subsequent failure of the peripheral localization of the alpha3beta1 integrin. We finally show that cell migration on pre-LN332 requires syndecan-1. Therefore, the LG4/5 domain in precursor LN332 appears to trigger intracellular signaling events, which participate in keratinocyte motility.
authors.affiliation: IFR128 BioSciences Lyon-Gerland, Institut de Biologie et Chimie des Protéines, UMR 5086, CNRS, University Lyon1, 7 passage du Vercors, Lyon, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bachy
authors.forename: François
authors.initials: F
authors.lastname: Letourneur
authors.forename: Patricia
authors.initials: P
authors.lastname: Rousselle
mesh_terms: D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D004789:Enzyme Activation; D005354:Fibrosarcoma / Q000473:pathology; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006801:Humans; D039201:Integrin alpha3beta1 / Q000378:metabolism; D015603:Keratinocytes / Q000502:physiology*; D008297:Male; D008545:Melanoma / Q000473:pathology; D018715:Microscopy, Video; D010590:Phalloidine; D010957:Plasmids; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012235:Rhodamines; D012867:Skin / Q000166:cytology; D053668:Syndecan-1 / Q000378:metabolism*; D014162:Transfection; D020764:cdc42 GTP-Binding Protein / Q000032:analysis / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000032:analysis / Q000378:metabolism; D000097794:Kalinin
chemical_list: D015815:Cell Adhesion Molecules; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D039201:Integrin alpha3beta1; D010590:Phalloidine; D011994:Recombinant Proteins; D012235:Rhodamines; D053668:Syndecan-1; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D000097794:Kalinin; C508241:SDC1 protein, human