Topic
Glycoprotein binding
About: Glycoprotein binding is a research topic. Over the lifetime, 152 publications have been published within this topic receiving 5205 citations.
Papers published on a yearly basis
Papers
TL;DR: The uptake of bovine milk exosomes is mediated by endocytosis and depends on cell and exosome surface glycoproteins in human and rat intestinal cells.
Abstract: Background: MicroRNAs play essential roles in gene regulation. A substantial fraction of microRNAs in tissues and body fluids is encapsulated in exosomes, thereby conferring protection against degradation and a pathway for intestinal transport. MicroRNAs in cow milk are bioavailable in humans.
Objective: This research assessed the transport mechanism of bovine milk exosomes, and therefore microRNAs, in human and rodent intestinal cells.
Methods: The intestinal transport of bovine milk exosomes and microRNAs was assessed using fluorophore-labeled bovine milk exosomes in human colon carcinoma Caco-2 cells and rat small intestinal IEC-6 cells. Transport kinetics and mechanisms were characterized using dose-response studies, inhibitors of vesicle transport, carbohydrate competitors, proteolysis of surface proteins on cells and exosomes, and transepithelial transport in transwell plates.
Results: Exosome transport exhibited saturation kinetics at 37°C [Michaelis constant (Km) = 55.5 ± 48.6 μg exosomal protein/200 μL of media; maximal transport rate = 0.083 ± 0.057 ng of exosomal protein · 81,750 cells−1 · h−1] and decreased by 64% when transport was measured at 4°C, consistent with carrier-mediated transport in Caco-2 cells. Exosome uptake decreased by 61–85% under the following conditions compared with controls in Caco-2 cells: removal of exosome and cell surface proteins by proteinase K, inhibition of endocytosis and vesicle trafficking by synthetic inhibitors, and inhibition of glycoprotein binding by carbohydrate competitors. When milk exosomes, at a concentration of 5 times the Km, were added to the upper chamber in transwell plates, Caco-2 cells accumulated miR-29b and miR-200c in the lower chamber, and reverse transport was minor. Transport characteristics were similar in IEC-6 cells and Caco-2 cells, except that substrate affinity and transporter capacity were lower and higher, respectively.
Conclusion: The uptake of bovine milk exosomes is mediated by endocytosis and depends on cell and exosome surface glycoproteins in human and rat intestinal cells.
336 citations
TL;DR: Use of a surface plasmon resonance direct binding assay and unbiased computational ligand docking indicates that heparan sulfate interacts with the GAG-binding motif at the S1/S2 site on each monomer interface in the trimeric SARS-CoV-2 SGP, and at another site when the receptor-binding domain is in an open conformation.
298 citations
TL;DR: Calnexin and calreticulin exhibited the same relative affinities when competing for binding to the Glc1Man9GlcNAc2 oligosaccharide, and differential glycoprotein binding cannot be attributed to differences in the lectin specificities or binding affinITIES.
Abstract: Calnexin and calreticulin are homologous molecular chaperones of the endoplasmic reticulum. Their binding to newly synthesized glycoproteins is mediated, at least in part, by a lectin site that recognizes the early N-linked oligosaccharide processing intermediate, Glc1Man9GlcNAc2. We compared the oligosaccharide binding specificities of calnexin and calreticulin in an effort to determine the basis for reported differences in their association with various glycoproteins. Using mono-, di-, and oligosaccharides to inhibit the binding of Glc1Man9GlcNAc2 to calreticulin and to a truncated, soluble form of calnexin, we show that the entire Glc alpha 1-3Man alpha 1-2Man alpha 1-2Man structure, extending from the alpha 1-3 branch point of the oligosaccharide core, is recognized by both proteins. Furthermore, analysis of the binding of monoglucosylated oligosaccharides containing progressively fewer mannose residues suggests that for both proteins the alpha 1-6 mannose branch point of the oligosaccharide core is also essential for recognition. Consistent with their essentially identical substrate specificities, calnexin and calreticulin exhibited the same relative affinities when competing for binding to the Glc1Man9GlcNAc2 oligosaccharide. Thus, differential glycoprotein binding cannot be attributed to differences in the lectin specificities or binding affinities of calnexin and calreticulin. We also examined the effects of ATP, calcium, and disulfide reduction on the lectin properties of calnexin and calreticulin. Whereas oligosaccharide binding was only slightly enhanced for both proteins in the presence of high concentrations of a number of adenosine nucleotides, removal of bound calcium abrogated oligosaccharide binding, an effect that was largely reversible upon readdition of calcium. Disulfide reduction had no effect on oligosaccharide binding by calnexin, but binding by calreticulin was inhibited by 70%. Finally, deletion mutagenesis of calnexin and calreticulin identified a central proline-rich region characterized by two tandem repeat motifs as a segment capable of binding oligosaccharide. This segment bears no sequence homology to the carbohydrate recognition domains of other lectins.
261 citations
TL;DR: Direct biochemical evidence is demonstrated for association of the carboxy‐terminal region of dystrophin with the glycoprotein complex and the binding site is found to lie further inward than previously expected and confined to the cysteine‐rich domain.
217 citations
TL;DR: The approach was demonstrated in the analysis of carbohydrate expression on two mammalian cell lines and showed that the lectins were effectively immobilized on the surface and retained their carbohydrate-binding specificities.
Abstract: We present a strategy for the analysis of cell surface carbohydrate expression patterns using lectin arrays fabricated on gold surfaces. Antibody and glycoprotein binding experiments showed that the lectins were effectively immobilized on the surface and retained their carbohydrate-binding specificities. The approach was demonstrated in the analysis of carbohydrate expression on two mammalian cell lines.
196 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 18 |
| 2020 | 9 |
| 2019 | 4 |
| 2018 | 8 |
| 2017 | 4 |
| 2016 | 2 |