Cell surface glycosaminoglycans do not serve as ligands for PECAM-1. PECAM-1 is not a heparin-binding protein

Qi Hong Sun, Cathy Paddock, Gian P. Visentin, Mark M. Zukowski, William A. Muller, Peter J. Newman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Previous studies have suggested that PECAM-1 mediates cellular interactions via both homophilic and heterophilic adhesive mechanisms. Cell surface glycoaminoglycans have been implicated as one of the heterophilic ligands for PECAM-1. To determine whether PECAM-1 is capable of interacting directly with glycosaminoglycans, we examined the adhesive properties of multiple monovalent and multivalent forms of this adhesion molecule. We found that the binding of a bivalent PECAM-1/IgG chimetic protein or multivalent PECAM-1-containing proteoliposomes to multiple different cell lines was 1) strictly dependent upon cell surface expression of PECAM-1 and 2) unaffected by the presence of excess heparin or heparan sulfate. The extracellular domain of PECAM-1 failed to interact specifically with heparinSepharose, 3H- labeled heparin, or a heparin-bovine serum albumin conjugate. In addition, an amino acid sequence motif inadvertently created by the juxtaposition of PECAM-1 and IgG sequences within the hinge region of certain PECAM-1/IgG chimeric constructs was found to confer glycosaminoglycan binding properties not normally present within the extracellular domain of the native molecule. Together, these data suggest that the mechanism by which heparin is able to affect PECAM-1-dependent cell-cell adhesion is indirect and occurs via inhibition of events that occur downstream from PECAM-1 engagement.

Original languageEnglish (US)
Pages (from-to)11483-11490
Number of pages8
JournalJournal of Biological Chemistry
Volume273
Issue number19
DOIs
StatePublished - May 8 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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