Galectin-3 alters the lateral mobility and clustering of β1-integrin receptors

PLoS One. 2017 Oct 10;12(10):e0184378. doi: 10.1371/journal.pone.0184378. eCollection 2017.

Abstract

Glycoprotein receptors are influenced by myriad intermolecular interactions at the cell surface. Specific glycan structures may interact with endogenous lectins that enforce or disrupt receptor-receptor interactions. Glycoproteins bound by multivalent lectins may form extended oligomers or lattices, altering the lateral mobility of the receptor and influencing its function through endocytosis or changes in activation. In this study, we have examined the interaction of Galectin-3 (Gal-3), a human lectin, with adhesion receptors. We measured the effect of recombinant Gal-3 added exogenously on the lateral mobility of the α5β1 integrin on HeLa cells. Using single-particle tracking (SPT) we detected increased lateral mobility of the integrin in the presence of Gal-3, while its truncated C-terminal domain (Gal-3C) showed only minor reductions in lateral mobility. Treatment of cells with Gal-3 increased β1-integrin mediated migration with no apparent changes in viability. In contrast, Gal-3C decreased both cell migration and viability. Fluorescence microscopy allowed us to confirm that exogenous Gal-3 resulted in reorganization of the integrin into larger clusters. We used a proteomics analysis to confirm that cells expressed endogenous Gal-3, and found that addition of competitive oligosaccharide ligands for the lectin altered the lateral mobility of the integrin. Together, our results are consistent with a Gal-3-integrin lattice model of binding and confirm that the lateral mobility of integrins is natively regulated, in part, by galectins.

MeSH terms

  • Cell Adhesion / genetics
  • Cell Movement / drug effects
  • Endocytosis / genetics*
  • Galectin 3 / administration & dosage
  • Galectin 3 / genetics*
  • Gene Expression Regulation
  • Glycoproteins / genetics
  • Glycoproteins / metabolism
  • HeLa Cells
  • Humans
  • Integrin alpha5beta1 / genetics
  • Integrin alpha5beta1 / metabolism*
  • Oligosaccharides / metabolism
  • Protein Binding
  • Proteomics*

Substances

  • Galectin 3
  • Glycoproteins
  • Integrin alpha5beta1
  • Oligosaccharides

Grants and funding

This work was supported by the Alberta Glycomics Centre and the Natural Sciences and Engineering Research Council of Canada (NSERC). MAH acknowledges support from an NSERC CGS-D scholarship. JR and ME were supported by the University of Alberta Research Experience (UARE) program.