Secretion of cholesteryl ester transfer protein-lipoprotein complexes by human HepG2 hepatocytes |
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Authors: | R A Faust M C Cheung J J Albers |
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Institution: | Department of Pathology, University of Washington School of Medicine, Seattle 98104-2499. |
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Abstract: | We have employed immunoaffinity chromatography to characterize the distribution of cholesteryl ester transfer activity in particles secreted by HepG2 hepatocytes. HepG2-secreted cholesteryl ester transfer activity is associated with apoprotein (apo) A-I (58%) as well as apo A-II (55%), and is not associated with apo B or E. In contrast, our previous studies have shown that most (88%) cholesteryl ester transfer activity in human plasma is associated with apo A-I whereas very little (7%) is associated with apo A-II. Thus, the distribution of cholesteryl ester transfer activity in plasma particles likely reflects active remodeling of nascent particles in the plasma compartment. Further data suggested that HepG2 cells secrete a lipid transfer inhibitor activity which is associated with apo E-containing lipoprotein particles. This inhibitory activity is heat labile. |
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