Motogenic Sites in Human Fibronectin Are Masked by Long Range Interactions

Ioannis Vakonakis, David Staunton, Ian R. Ellis, Peter Sarkies, Aleksandra Flanagan, Ana M. Schor, Seth L. Schor, Iain D. Campbell

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    41 Citations (Scopus)

    Abstract

    Fibronectin (FN) is a large extracellular matrix glycoprotein important for development and wound healing in vertebrates. Recent work has focused on the ability of FN fragments and embryonic or tumorigenic splicing variants to stimulate fibroblast migration into collagen gels. This activity has been localized to specific sites and is not exhibited by full-length FN. Here we show that an N-terminal FN fragment, spanning the migration stimulation sites and including the first three type III FN domains, also lacks this activity. A screen for interdomain interactions by solution-state NMR spectroscopy revealed specific contacts between the Fn N terminus and two of the type III domains. A single amino acid substitution, R222A, disrupts the strongest interaction, between domains (4-5)FnI and (3)FnIII, and restores motogenic activity to the FN N-terminal fragment. Anastellin, which promotes fibril formation, destabilizes 3FnIII and disrupts the observed (4-5)FnI-(3)FnIII interaction. We discuss these findings in the context of the control of cellular activity through exposure of masked sites.

    Original languageEnglish
    Pages (from-to)15668-15675
    Number of pages8
    JournalJournal of Biological Chemistry
    Volume284
    Issue number23
    DOIs
    Publication statusPublished - 5 Jun 2009

    Keywords

    • HUMAN-PLASMA FIBRONECTIN
    • MIGRATION-STIMULATING FACTOR
    • FLUORESCENCE ENERGY-TRANSFER
    • GELATIN-BINDING DOMAIN
    • I COLLAGEN
    • FIBROBLAST MIGRATION
    • CRYSTAL-STRUCTURES
    • CELL-MIGRATION
    • FRAGMENT
    • MATRIX

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