Cooperative role for activated α4β1 integrin and chondroitin sulfate proteoglycans in cell adhesion to the heparin III domain of fibronectin: Identification of a novel heparin and cell binding sequence in repeat III5

José V. Moyano, Barbara Carnemolla, Juan P. Albar, Alessandra Leprini, Barbara Gaggero, Luciano Zardi, Angeles Garcia-Pardon

Research output: Contribution to journalArticlepeer-review

Abstract

We recently reported that the heparin (Hep) III domain of fibronectin contains the H2 cell adhesion site in repeat III5 which binds activated α4 integrins. We have now further characterized the heparin and cell binding activities of this domain. A recombinant fragment containing repeats III4- III5 (FN-III4-5) induced Jurkat cell adhesion upon integrin activation with Mn2+ or TS2/16 monoclonal antibody (anti-β1). Adhesion of Mn2+treated cells to FN-III4-5 or FN-III5 fragments was inhibited by chondroitinase ABC and ACII but not by the anti-α4 monoclonal antibody HP2/1. In contrast, HP2/1 completely blocked adhesion of TS2/16-treated cells while chondroitinase had a partial (FN-III4-5) or minor (FN-III5) effect. Thus, the role of each receptor depended on the Stimulus used to activate α4β1. The combination of HP2/1 and chondroitinase at dilutions which did not inhibit when used individually abolished adhesion of Mn2+ or TS2/16-treated cells to both fragments, indicating a cooperative effect between α4β1 and chondroitin sulfate proteoglycans (CSPG). Furthermore, we have identified a 20-amino acid sequence in III5 (HBP/III5) which binds heparin and induces cell adhesion via CSPG exclusively. Although soluble HBP/III5 was a poor inhibitor, when combined with H2, it abolished adhesion to FN-III4-5 and FN- III5 fragments. These results establish that adhesion to the Hep III domain involves the cooperation of activated α4β1 and CSPG and show that HBP/III5 is a novel heparin and CSPG-binding site contributing to cell adhesion to this domain.

Original languageEnglish
Pages (from-to)135-142
Number of pages8
JournalJournal of Biological Chemistry
Volume274
Issue number1
DOIs
Publication statusPublished - Jan 1 1999

ASJC Scopus subject areas

  • Biochemistry

Fingerprint

Dive into the research topics of 'Cooperative role for activated α4β1 integrin and chondroitin sulfate proteoglycans in cell adhesion to the heparin III domain of fibronectin: Identification of a novel heparin and cell binding sequence in repeat III5'. Together they form a unique fingerprint.

Cite this