Characterization of human high-density lipoprotein subclasses LP A-I and LP A-I/A-II and binding to HepG2 cells.
Plasma HDL can be classified according to their apolipoprotein content into at least two types of lipoprotein particles: lipoproteins containing both apo A-I and apo A-II (LP A-I/A-II) and lipoproteins with apo A-I but without apo A-II (LP A-I). LP A-I and LP A-I/A-II were isolated by immuno-affinity chromatography. LP A-I has a higher cholesterol content and less protein compared to LP A-I/A-II. The average particle mass of LP A-I is higher (379 kDa) than the average particle weight of LP A-I/A-II (269 kDa). The binding of 125I-LP A-I to HepG2 cells at 4 degrees C, as well as the uptake of [3H]cholesteryl ether-labelled LP A-I by HepG2 cells at 37 degrees C, was significantly higher than the binding and uptake of LP A-I/A-II. It is likely that both binding and uptake are mediated by apo A-I. Our results do not provide evidence in favor of a specific role for apo A-II in the binding and uptake of HDL by HepG2 cells.
Kilsdonk
E P
EP
Department of Biochemistry I, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands.
Van Gent
T
T
Van Tol
A
A
D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A / Q000032:analysis*; D001692:Biological Transport; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D008076:Cholesterol, HDL / Q000032:analysis / Q000378:metabolism; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D006801:Humans; D008075:Lipoproteins, HDL / Q000032:analysis* / Q000145:classification; D008099:Liver / Q000032:analysis; D008113:Liver Neoplasms / Q000378:metabolism; D014407:Tumor Cells, Cultured
D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001054:Apolipoproteins A; D008076:Cholesterol, HDL; D008075:Lipoproteins, HDL