title: Assembly and tissue functions of early embryonic laminins and netrins.
abstract: Vertebrate laminins and netrins share N-terminal domain structure, but appear to be only distantly related. Both families can be divided into different subfamilies on the basis of structural considerations. Recent observations suggest that specific laminin and netrin members have developmental functions that are highly conserved across species. Vertebrate laminin-1 (alpha1beta1gamma1) and laminin-10 (alpha5beta1gamma1), like the two Caenorhabditis elegans laminins, are embryonically expressed and are essential for basement membrane assembly. Basement membrane assembly is a cooperative process in which laminins polymerize through their LN domains and anchor to the cell surface through their G domains; this leads to cell signaling through integrins and dystroglycan (and possibly other receptors) recruited to the adherent laminin. Netrins may associate with this network through heterotypic LN domain interactions. Vertebrate netrin-1, like invertebrate UNC-6/netrins, is well known as an extracellular guidance cue that directs axon migration towards or away from the ventral midline. It also regulates cell adhesions and migrations, probably as a basement membrane component. Although sharing structural features, these two vertebrate protein families are quite distinct, having both retained members that mediate the ancestral developmental functions.
authors.affiliation: Department of Pathology and Laboratory Medicine, UMDNJ, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, New Jersey 08854, USA. yurchenc@umdnj.edu
authors.forename: Peter D
authors.initials: PD
authors.lastname: Yurchenco
authors.forename: William G
authors.initials: WG
authors.lastname: Wadsworth
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000502:physiology; D001485:Basement Membrane / Q000196:embryology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion; D002465:Cell Movement / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D019143:Evolution, Molecular; D007797:Laminin / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D000075385:Netrins; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology*; D014714:Vertebrates / Q000196:embryology* / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D007797:Laminin; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D000075385:Netrins; C078146:UNC-6 protein, C elegans