%0 Journal Article %J Biochem Biophys Res Commun %D 2012 %T Characterization of the interaction between hydroxypropyl guar galactomannan and galectin-3 %A Woodward, Ashley M %A Senchyna, Michelle %A Williams, Ravaughn %A Argüeso, Pablo %K CA-125 Antigen %K Cell Line %K Cornea %K Galactose %K Galectin 3 %K Humans %K Keratinocytes %K Mannans %K Membrane Proteins %X Multivalent galactose ligands have been proposed for selective targeting of carbohydrate-binding proteins on epithelial cell surfaces, both in normal and pathological conditions. One cellular partner is galectin-3, a β-galactoside-binding protein present on many epithelial linings, such as those of the ocular surface. In this study, we investigated the ability of hydroxypropyl guar galactomannan (HPGG) to bind recombinant galectin-3 and to target the apical surface of differentiated human corneal keratinocytes. Pull-down and slot-blot assays demonstrated that fluorescence-labeled HPGG bound recombinant galectin-3 through a galactose-dependent mechanism. In contrast, no binding of HPGG could be detected towards recombinant galectin-8 or -9. In a cell culture system, HPGG bound weakly to biotinylated cell surface corneal isolates containing endogenous galectin-3, and incubation of HPGG with corneal keratinocytes in culture resulted in discrete, galactose-independent, binding to the cell surface. Moreover, HPGG failed to elute the biological counter-receptor MUC16 from galectin-3 affinity columns. We conclude that HPGG binds galectin-3 through the conventional carbohydrate-recognition domain in vitro, but not in a biological system, suggesting that endogenous carbohydrate ligands on epithelial cell surface glycocalyces impair HPGG biorecognition. %B Biochem Biophys Res Commun %V 424 %P 12-7 %8 2012 Jul 20 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/22683626?dopt=Abstract %R 10.1016/j.bbrc.2012.05.160