Apolipoprotein B synthesized by Hep G2 cells undergoes fatty acid acylation
- PMID: 2846736
Apolipoprotein B synthesized by Hep G2 cells undergoes fatty acid acylation
Abstract
Apolipoprotein B is the principal protein associated with cholesterol transport in the blood and has been proposed to play a central role in human atherogenesis. The unique hydrophobic nature of this large (512 kDa), glycosylated apolipoprotein differs from that of the other apolipoproteins. Since another apolipoprotein, apolipoprotein A-I, has been recently shown to have covalently bound fatty acids, potential fatty acid acylation of apolipoprotein B was investigated. The human hepatoma cell line, Hep G2, synthesizes apoB-100 and secretes the apolipoprotein into the culture medium. After a 24-hr incubation with [14C]palmitate and [14C]stearate, the label was incorporated into apoB-100 when assessed by a sodium dodecyl sulfate polyacrylamide gel electrophoresis, autoradiography, immunoblot analysis, and immunoprecipitation. Hydroxylamine treatment, which hydrolyzes ester and thioester bonds, removed the radiolabel. ApoB-100 isolated from Hep G2 cells by ultracentrifugation and preparative sodium dodecyl sulfate gel electrophoresis was hydrolyzed and analyzed by gas-liquid chromatography-mass spectrometry. In contrast to circulating apoB in low density lipoproteins, both palmitate and stearate were present in newly synthesized apoB-100. These results establish that newly synthesized apoB-100 undergoes covalent acylation with palmitate and stearate. The acylation of apoB may play an important role in lipoprotein particle secretion. In addition, derangements in apoB fatty acid acylation may lead to dyslipoproteinemia.
Similar articles
-
Human apolipoprotein A-I. Post-translational modification by fatty acid acylation.J Biol Chem. 1986 Mar 25;261(9):3911-4. J Biol Chem. 1986. PMID: 3005308
-
Regulation of apoprotein synthesis and secretion in the human hepatoma Hep G2. The effect of exogenous lipoprotein.J Biol Chem. 1988 Sep 25;263(27):13880-90. J Biol Chem. 1988. PMID: 2843542
-
The effects of fatty acids on apolipoprotein B secretion by human hepatoma cells (HEP G2).Atherosclerosis. 2000 Jun;150(2):255-64. doi: 10.1016/s0021-9150(99)00374-3. Atherosclerosis. 2000. PMID: 10856517
-
Regulation of hepatic secretion of apolipoprotein B-containing lipoproteins: information obtained from cultured liver cells.J Lipid Res. 1993 Feb;34(2):167-79. J Lipid Res. 1993. PMID: 8381452 Review.
-
Apolipoprotein B: structure, biosynthesis and role in the lipoprotein assembly process.Atherosclerosis. 1987 Nov;68(1-2):1-17. doi: 10.1016/0021-9150(87)90088-8. Atherosclerosis. 1987. PMID: 3318851 Review.
Cited by
-
Recent progress in understanding protein and lipid factors affecting hepatic VLDL assembly and secretion.Nutr Metab (Lond). 2010 Apr 27;7:35. doi: 10.1186/1743-7075-7-35. Nutr Metab (Lond). 2010. PMID: 20423497 Free PMC article.
-
A role for palmitoylation in the quality control, assembly and secretion of apolipoprotein B.Biochem J. 2004 Jan 1;377(Pt 1):121-30. doi: 10.1042/BJ20030951. Biochem J. 2004. PMID: 14498830 Free PMC article.
-
Palmitoylation of apolipoprotein B is required for proper intracellular sorting and transport of cholesteroyl esters and triglycerides.Mol Biol Cell. 2000 Feb;11(2):721-34. doi: 10.1091/mbc.11.2.721. Mol Biol Cell. 2000. PMID: 10679026 Free PMC article.
-
N-3 fatty acids stimulate intracellular degradation of apoprotein B in rat hepatocytes.J Clin Invest. 1993 Apr;91(4):1380-9. doi: 10.1172/JCI116340. J Clin Invest. 1993. PMID: 8473489 Free PMC article.
-
Solubilization and separation of two distinct carnitine acyltransferases from hepatic microsomes: characterization of the malonyl-CoA-sensitive enzyme.Biochem J. 1995 Sep 15;310 ( Pt 3)(Pt 3):989-95. doi: 10.1042/bj3100989. Biochem J. 1995. PMID: 7575437 Free PMC article.
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Miscellaneous