Abnormal accumulation and recycling of glycoproteins visualized in Niemann–Pick type C cells using the chemical reporter strategy
| Autor: | Heather Flanagan-Steet, Margreet A. Wolfert, Ngalle Eric Mbua, Geert-Jan Boons, Steven G. Johnson, Richard Steet |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Azides
Glycoconjugate Endosome Sialoglycoproteins Endocytic cycle Vesicular Transport Proteins Galactosamine Endosomes Biology Cell Line Niemann-Pick C1 Protein medicine Humans Glycoproteins chemistry.chemical_classification Multidisciplinary Niemann–Pick disease type C Membrane Glycoproteins beta-Cyclodextrins Intracellular Signaling Peptides and Proteins Dextrans Niemann-Pick Disease Type C Biological Sciences Fibroblasts medicine.disease Cell biology Membrane glycoproteins Protein Transport Cholesterol chemistry Biochemistry biology.protein Cholesterol storage Glycoprotein Carrier Proteins Lysosomes Glycoconjugates |
| Popis: | Niemann–Pick type C (NPC) disease is characterized by impaired cholesterol efflux from late endosomes and lysosomes and secondary accumulation of lipids. Although impaired trafficking of individual glycoproteins and glycolipids has been noted in NPC cells and other storage disorders, there is currently no effective way to monitor their localization and movement en masse . Using a chemical reporter strategy in combination with pharmacologic treatments, we demonstrate a disease-specific and previously unrecognized accumulation of a diverse set of glycoconjugates in NPC1-null and NPC2-deficient fibroblasts within endocytic compartments. These labeled vesicles do not colocalize with the cholesterol-laden compartments of NPC cells. Experiments using the endocytic uptake marker dextran show that the endosomal accumulation of sialylated molecules can be largely attributed to impaired recycling as opposed to altered fusion of vesicles. Treatment of either NPC1-null or NPC2-deficient cells with cyclodextrin was effective in reducing cholesterol storage as well as the endocytic accumulation of sialoglycoproteins, demonstrating a direct link between cholesterol storage and abnormal recycling. Our data further demonstrate that this accumulation is largely glycoproteins, given that inhibitors of O -glycan initiation or N -glycan processing led to a significant reduction in staining intensity. Taken together, our results provide a unique perspective on the trafficking defects in NPC cells, and highlight the utility of this methodology in analyzing cells with altered recycling and turnover of glycoproteins. |
| Databáze: | OpenAIRE |
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