Generation of lipid polarity in intestinal epithelial (Caco-2) cells: Sphingolipid synthesis in the Golgi complex and sorting before vesicular traffic to the plasma membrane
| Autor: | van 't Hof, W.J., van Meer, G., Membrane Enzymology, Universiteit Utrecht, Dep Scheikunde |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1990 |
| Předmět: |
Ceramide
Membrane lipids Golgi Apparatus In Vitro Techniques Biology Glucosylceramides Kidney Cell membrane Membrane Lipids chemistry.chemical_compound symbols.namesake Dogs Intestinal mucosa medicine Animals Humans Intestinal Mucosa Sphingolipids Cell Membrane technology industry and agriculture Kidney metabolism Biological Transport Articles Cell Biology Golgi apparatus Sphingomyelins Cell biology Kinetics medicine.anatomical_structure chemistry Transcytosis symbols lipids (amino acids peptides and proteins) Sphingomyelin |
| Zdroj: | Journal of Cell Biology, 111(3), 977. Rockefeller University Press The Journal of Cell Biology |
| ISSN: | 0021-9525 |
| Popis: | Generation of intestinal epithelial lipid polarity was studied in Caco-2 cells. Confluent monolayers on filters incorporated the exchangeable lipid N-6-NBD-aminocaproyl-sphingosine (C6-NBD-ceramide) from liposomes. The fluorescent ceramide was converted equally to C6-NBD-glucosylceramide and C6-NBD-sphingomyelin, analogues of lipids enriched on the apical and basolateral surface, respectively, of intestinal cells in vivo. Below 16 degrees C, where vesicular traffic is essentially blocked, each fluorescent product accumulated in the Golgi area. At 37 degrees C, 50% had been transported to the cell surface within 0.5 h, as measured by selective extraction of the fluorescent lipids onto BSA in the medium ("back-exchange") at 10 degrees C. Transport to the two surfaces could be assayed separately, as a diffusion barrier existed for both NBD-lipids and BSA. C6-NBD-glucosylceramide was enriched twofold apically, whereas C6-NBD-sphingomyelin was equally distributed over both domains. Polarities did not decrease when 37 degrees C incubations were carried out in the presence of increasing BSA concentrations to trap the fluorescent lipids immediately after their arrival at the cell surface. Within 10 min from the start of synthesis, both products displayed their typical surface polarity. Lipid transcytosis displayed a half time of hours. In conclusion, newly synthesized sphingolipids in Caco-2 cells are sorted before reaching the cell surface. Transcytosis is not required for generating the in vivo lipid polarity. |
| Databáze: | OpenAIRE |
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