Sialidase treatment exposes the β1-integrin active ligand binding site on HL60 cells and increases binding to fibronectin

R. K. Pretzlaff, V. W. Xue, M. E. Rowin

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

The migration of neutrophils from the circulation to areas of inflammation is the result of the sequential activation of multiple cellular adhesion molecules. β1-Integrins are cell surface glycoproteins and the class of adhesion molecules responsible for binding to the extracellular matrix. The goal of this study was to determine the contribution of glycosylation, specifically the presence of sialic acid, to β1-integrin adhesion in a neutrophil model. β1-Integrins on differentiated HL60 cells were remodeled by treatment with the exoglycosidases, sialidase and β-galactosidase. β1-Integrin activity was determined by measuring adherence to the extracellular matrix protein fibronectin. The expression of β1-integrins, β2-integrins and activated β1-integrins was determined by flow cytometry. Remodeling of β1-integrins by treatment with sialidase increased adhesion by greater than 100%. Flow cytometric analysis of remodeled β1-integrins demonstrated an increased expression of the activated β1-integrin, but only minor increases in the expression of total β1-and β2-integrins. We postulate that glycosidase treatment increases adhesion and expression of activated β1-integrins by exposure of the normally hidden ligand-binding site. The glycosylation of β1-integrins on neutrophils may act to hide the ligand-binding site in unstimulated cells thereby contributing to the affinity modulation observed in neutrophil β1-integrin function.

Original languageEnglish (US)
Pages (from-to)491-500
Number of pages10
JournalCell Adhesion and Communication
Volume7
Issue number6
StatePublished - 2000
Externally publishedYes

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Keywords

  • β1-Integrin
  • Extracellular matrix
  • Glycosidase
  • Neutrophil
  • Sialidase

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry

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