title: Molecular basis of elastic fiber formation. Critical interactions and a tropoelastin-fibrillin-1 cross-link.
abstract: We have investigated the molecular basis of elastic fiber formation on fibrillin microfibrils. Binding assays revealed high affinity calcium-independent binding of two overlapping fibrillin-1 fragments (encoded by central exons 18-25 and 24-30) to tropoelastin, which, in microfibrils, map to an exposed "arms" feature adjacent to the beads. A further binding site within an adjacent fragment (encoded by exons 9-17) was within an eight-cysteine motif designated TB2 (encoded by exons 16 and 17). Binding to TB2 was ablated by the presence of N-terminal domains (encoded by exons 1-8) and reduced after deleting the proline-rich region. A novel transglutaminase cross-link between tropoelastin and fibrillin-1 fragment (encoded by exons 9-17) was localized by mass spectrometry to a sequence encoded by exon 17. The high affinity binding and cross-linking of tropoelastin to a central fibrillin-1 sequence confirm that this association is fundamental to elastic fiber formation. Microfibril-associated glycoprotein-1 showed calcium-dependent binding of moderate affinity to fibrillin-1 N-terminal fragment (encoded by exons 1-8), which localize to the beads. Microfibril-associated glycoprotein-1 thus contributes to microfibril organization but may also form secondary interactions with adjacent microfibril-bound tropoelastin.
authors.affiliation: Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, United Kingdom.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rock
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Cain
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Freeman
authors.forename: Amanda
authors.initials: A
authors.lastname: Morgan
authors.forename: Kieran
authors.initials: K
authors.lastname: Mellody
authors.forename: Andrew
authors.initials: A
authors.lastname: Marson
authors.forename: C Adrian
authors.initials: CA
authors.lastname: Shuttleworth
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Weiss
authors.forename: Cay M
authors.initials: CM
authors.lastname: Kielty
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003285:Contractile Proteins / Q000737:chemistry / Q000378:metabolism; D003432:Cross-Linking Reagents; D004547:Elastic Tissue / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000378:metabolism; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D020894:Microfibrils / Q000737:chemistry / Q000378:metabolism; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D000072260:RNA Splicing Factors; D011994:Recombinant Proteins; D014333:Tropoelastin / Q000737:chemistry / Q000378:metabolism*; D054392:Adipokines
chemical_list: D003285:Contractile Proteins; D003432:Cross-Linking Reagents; D016326:Extracellular Matrix Proteins; D000071838:Fibrillin-1; D000071837:Fibrillins; D008840:Microfilament Proteins; D000072260:RNA Splicing Factors; D011994:Recombinant Proteins; D014333:Tropoelastin; C000605722:FBN1 protein, human; D054392:Adipokines; C016598:microfibrillar protein