The existence of B/E and E receptors on Hep-G2 cells: a study using colloidal gold- and 125I-labeled lipoproteins.
The presence of specific receptors for apolipoprotein B (low-density lipoproteins) and apolipoprotein E (HDL-E) on Hep-G2 cells and human skin fibroblasts was studied by chemical methods and by electron microscopy using a differential gold labeling technique. Fibroblasts bound both types of lipoproteins to one and the same receptor (B/E receptor) as deduced from competition experiments with HDL-E and LDL. Labeled HDL-E, on the other hand, was only partially displaced by cold LDL but was completely displaced by unlabeled HDL-E. Scatchard analysis of lipoprotein binding to Hep-G2 cells revealed an approx 10 times higher binding affinity of apoE-containing lipoproteins as compared to apoB-containing ones. No differences between apoE- or apoB-containing lipoproteins with respect to the morphology of cell binding and intracellular processing were observed. The results are compatible with the concept that Hep-G2 cells possess two kinds of receptors, one specific for apoB- and apoE-containing lipoproteins (B/E receptor) and another specific for apoE only. From these studies we conclude that Hep-G2 cells may serve as a suitable model for studying the lipoprotein metabolism in the liver.
D001055:Apolipoproteins B / Q000378:metabolism*; D001057:Apolipoproteins E / Q000378:metabolism*; D001667:Binding, Competitive; D002460:Cell Line; D005347:Fibroblasts / Q000378:metabolism; D006048:Gold Colloid, Radioactive; D006801:Humans; D007457:Iodine Radioisotopes; D008099:Liver / Q000378:metabolism; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018110:Receptors, Lipoprotein
D001055:Apolipoproteins B; D001057:Apolipoproteins E; D006048:Gold Colloid, Radioactive; D007457:Iodine Radioisotopes; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011956:Receptors, Cell Surface; D018110:Receptors, Lipoprotein; C032531:apolipoprotein B,E receptor