Further studies on the interaction of migrating keratinocytes with fibrinogen

Donald J. Donaldson, James T. Mahan, David L. Amrani, David H. Farrell, Joan H. Sobel

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

If glass implants placed under one edge of a skin wound in the adult newt are coated with fibrinogen (FGN), keratinocytes from the wound periphery migrate onto the implant. To learn more about the site(s) in FGN that permits this migration, we exposed keratinocytes to implants coated with forms of FGN containing modifications or deletions in the 3 most commonly studied cell binding sites; the RGDF sequence at Aa 95-98, RGDS at Aα 572-575 and the carboxy terminal 12 amino acids in the γA chain. Recombinant FGN with either RGD sequence altered to RGE supported migration as well as unmodified FGN did. Replacement of the carboxy terminal 4 amino acids in the γA chain by a 20 amino acid sequence that disrupts the ability of the γ terminus to mediate platelet aggregation (the γ variant) likewise had no effect. Nor did simultaneous antibody blockade of the RGDS, RGDF, and γA sites have any effect. At its best, Dhem1, a fragment containing the RGDS and γA sites, produced only about half as much migration as the maximum obtained on intact FGN. Dhem2, a fragment differing from Dheml only by having a γ variant in place of γA, was even less active. Two other D fragments, both of which were missing a large part of the Aa chain, and one of which contained none of the three major binding sites, supported considerable migration, suggesting that loss of the Aα chain COOH terminus reveals a site that was not exposed in Dheml and 2. Aα chain fragments containing the RGDF or RGDS sequence were active, but a much larger fragment without RGD was inactive. A soluble peptide consisting of the sequence, RGDS, was a potent inhibitor of migration on FGN but RGDF and the γA pentapeptide, KQAGD, were minimally effective. Longer versions of these peptides decreased the effectiveness in all cases. These results suggest that under certain circumstances, newt keratinocytes may interact with each of the 3 major binding sites in FGN as well as a site outside these sequences.

Original languageEnglish (US)
Pages (from-to)299-308
Number of pages10
JournalCell Communication and Adhesion
Volume2
Issue number4
DOIs
StatePublished - Jan 1 1994

Keywords

  • Fibrinogen
  • Keratinocytes
  • Migration

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology

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