|
|
||||||||
Original Article |
Correspondence to: Khosrow Adeli
We studied the biogenesis of apolipoprotein B (apoB) in primary hepatocytes isolated from hamster liver, an animal model with striking resemblance to humans in lipoprotein metabolism. Hamster hepatocytes were found to assemble and secrete apoB-containing lipoproteins at a density of VLDL. Intracellular mechanisms of apoB biogenesis were investigated in both intact and permeabilized hamster hepatocytes. Translocational status of hamster apoB-100 was examined using trypsin protection assays in permeabilized cells as well as isolated microsomes which revealed that 27 42% of newly synthesized apoB was trypsin accessible as opposed to a control protein, transferrin, which was found to be essentially insensitive to exogenous trypsin. Subcellular fractionation of membrane and lumenal apoB pools indicated, however, that only a minor fraction of hamster apoB was associated with the microsomal membrane. Approximately 40% of newly synthesized apoB was found to be degraded post-translationally in a process sensitive to MG132. Immunoblotting analysis of apoB immunoprecipitates revealed ubiquitination of hamster apoB suggesting the involvement of the proteasome in its intracellular turnover. In addition to MG132, o-phenanthroline, a metalloprotease inhibitor, was also effective in stabilizing hamster apoB. Experiments in permeabilized hamster hepatocytes further confirmed post-translational instability of hamster apoB which was degraded over a 3-h chase generating proteolytic fragments including 167, 70, 57, and 46 kDa intermediates. Of these only the 70 kDa fragment was ALLN sensitive. Oleate treatment of hamster hepatocytes provided protection against intracellular apoB degradation, but did not stimulate its extracellular secretion. ApoB was assembled in the microsomal lumen into lipoprotein particles with densities of LDL and VLDL which were subsequently secreted as VLDL with a minor fraction forming HDL-like particles.
In summary, hamster hepatocytes appear to efficiently assemble and secrete apoB-containing VLDL, although a significant pool of newly synthesized apoB is retained intracellularly and becomes sensitive to proteasome-mediated degradation as well as other proteases in the secretory pathway, generating specific degradative intermediates.Taghibiglou, C., D. Rudy, S. C. Van Iderstine, A. Aiton, D. Cavallo, R. Cheung, and K. Adeli. Intracellular mechanisms regulating apoB-containing lipoprotein assembly and secretion in primary hamster hepatocytes. J. Lipid Res. 2000. 41: 499;513.
Supplementary key words: Syrian golden hamster, liver, lipoprotein, VLDL, synthesis, degradation, translocation
This article has been cited by other articles:
![]() |
B. Qin, W. Qiu, R. K. Avramoglu, and K. Adeli Tumor Necrosis Factor-{alpha} Induces Intestinal Insulin Resistance and Stimulates the Overproduction of Intestinal Apolipoprotein B48-Containing Lipoproteins Diabetes, February 1, 2007; 56(2): 450 - 461. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Qiu, R. K. Avramoglu, A. C. Rutledge, J. Tsai, and K. Adeli Mechanisms of glucosamine-induced suppression of the hepatic assembly and secretion of apolipoprotein B-100-containing lipoproteins J. Lipid Res., August 1, 2006; 47(8): 1749 - 1761. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Xu, C. Sztalryd, X. Lu, J. T. Tansey, J. Gan, H. Dorward, A. R. Kimmel, and C. Londos Post-translational Regulation of Adipose Differentiation-related Protein by the Ubiquitin/Proteasome Pathway J. Biol. Chem., December 30, 2005; 280(52): 42841 - 42847. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-P. F. Morand, J. Macri, and K. Adeli Proteomic Profiling of Hepatic Endoplasmic Reticulum-associated Proteins in an Animal Model of Insulin Resistance and Metabolic Dyslipidemia J. Biol. Chem., May 6, 2005; 280(18): 17626 - 17633. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Qiu, R. Kohen-Avramoglu, S. Mhapsekar, J. Tsai, R. C. Austin, and K. Adeli Glucosamine-Induced Endoplasmic Reticulum Stress Promotes ApoB100 Degradation: Evidence for Grp78-Mediated Targeting to Proteasomal Degradation Arterioscler. Thromb. Vasc. Biol., March 1, 2005; 25(3): 571 - 577. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Lewis, K. Uffelman, M. Naples, L. Szeto, M. Haidari, and K. Adeli Intestinal Lipoprotein Overproduction, a Newly Recognized Component of Insulin Resistance, Is Ameliorated by the Insulin Sensitizer Rosiglitazone: Studies in the Fructose-Fed Syrian Golden Hamster Endocrinology, January 1, 2005; 146(1): 247 - 255. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Qiu, R. K. Avramoglu, N. Dube, T. M. Chong, M. Naples, C. Au, K. G. Sidiropoulos, G. F. Lewis, J. S. Cohn, M. L. Tremblay, et al. Hepatic PTP-1B Expression Regulates the Assembly and Secretion of Apolipoprotein B-Containing Lipoproteins: Evidence From Protein Tyrosine Phosphatase-1B Overexpression, Knockout, and RNAi Studies Diabetes, December 1, 2004; 53(12): 3057 - 3066. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Lewis, S. Murdoch, K. Uffelman, M. Naples, L. Szeto, A. Albers, K. Adeli, and J. D. Brunzell Hepatic Lipase mRNA, Protein, and Plasma Enzyme Activity Is Increased in the Insulin-Resistant, Fructose-Fed Syrian Golden Hamster and Is Partially Normalized by the Insulin Sensitizer Rosiglitazone Diabetes, November 1, 2004; 53(11): 2893 - 2900. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. F. Lewis, M. Naples, K. Uffelman, N. Leung, L. Szeto, and K. Adeli Intestinal Lipoprotein Production Is Stimulated by an Acute Elevation of Plasma Free Fatty Acids in the Fasting State: Studies in Insulin-Resistant and Insulin-Sensitized Syrian Golden Hamsters Endocrinology, November 1, 2004; 145(11): 5006 - 5012. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-L. Zhang, A. Hernandez-Ono, C. Ko, K. Yasunaga, L.-S. Huang, and H. N. Ginsberg Regulation of Hepatic Apolipoprotein B-lipoprotein Assembly and Secretion by the Availability of Fatty Acids: I. DIFFERENTIAL RESPONSE TO THE DELIVERY OF FATTY ACIDS VIA ALBUMIN OR REMNANT-LIKE EMULSION PARTICLES J. Biol. Chem., April 30, 2004; 279(18): 19362 - 19374. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Haidari, N. Leung, F. Mahbub, K. D. Uffelman, R. Kohen-Avramoglu, G. F. Lewis, and K. Adeli Fasting and Postprandial Overproduction of Intestinally Derived Lipoproteins in an Animal Model of Insulin Resistance. EVIDENCE THAT CHRONIC FRUCTOSE FEEDING IN THE HAMSTER IS ACCOMPANIED BY ENHANCED INTESTINAL DE NOVO LIPOGENESIS AND ApoB48-CONTAINING LIPOPROTEIN OVERPRODUCTION J. Biol. Chem., August 23, 2002; 277(35): 31646 - 31655. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Carpentier, C. Taghibiglou, N. Leung, L. Szeto, S. C. Van Iderstine, K. D. Uffelman, R. Buckingham, K. Adeli, and G. F. Lewis Ameliorated Hepatic Insulin Resistance Is Associated with Normalization of Microsomal Triglyceride Transfer Protein Expression and Reduction in Very Low Density Lipoprotein Assembly and Secretion in the Fructose-fed Hamster J. Biol. Chem., August 2, 2002; 277(32): 28795 - 28802. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Marcil, E. Delvin, E. Seidman, L. Poitras, M. Zoltowska, C. Garofalo, and E. Levy Modulation of lipid synthesis, apolipoprotein biogenesis, and lipoprotein assembly by butyrate Am J Physiol Gastrointest Liver Physiol, August 1, 2002; 283(2): G340 - G346. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Taghibiglou, F. Rashid-Kolvear, S. C. Van Iderstine, H. Le-Tien, I. G. Fantus, G. F. Lewis, and K. Adeli Hepatic Very Low Density Lipoprotein-ApoB Overproduction Is Associated with Attenuated Hepatic Insulin Signaling and Overexpression of Protein-tyrosine Phosphatase 1B in a Fructose-fed Hamster Model of Insulin Resistance J. Biol. Chem., January 4, 2002; 277(1): 793 - 803. [Abstract] [Full Text] |
||||
![]() |
N. Sakata, T. E. Phillips, and J. L. Dixon Distribution, transport, and degradation of apolipoprotein B-100 in HepG2 cells J. Lipid Res., December 1, 2001; 42(12): 1947 - 1958. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Plonne, H.-P. Schulze, U. Kahlert, K. Meltke, H. Seidolt, A. J. Bennett, I. J. Cartwright, J. A. Higgins, U. Till, and R. Dargel Postnatal development of hepatocellular apolipoprotein B assembly and secretion in the rat J. Lipid Res., November 1, 2001; 42(11): 1865 - 1878. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Levy, D. Menard, E. Delvin, S. Stan, G. Mitchell, M. Lambert, E. Ziv, J. C. Feoli-Fonseca, and E. Seidman The Polymorphism at Codon 54 of the FABP2 Gene Increases Fat Absorption in Human Intestinal Explants J. Biol. Chem., October 19, 2001; 276(43): 39679 - 39684. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Le Petit-Thevenin, N. Bruneau, A. Nganga, D. Lombardo, and A. Verine Effects of arachidonic and docosahexaenoic acids on secretion and degradation of bile salt-dependent lipase in AR4-2J cells J. Lipid Res., August 1, 2001; 42(8): 1220 - 1230. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. A. Davis and T. Y. Hui 2000 George Lyman Duff Memorial Lecture : Atherosclerosis Is a Liver Disease of the Heart Arterioscler. Thromb. Vasc. Biol., June 1, 2001; 21(6): 887 - 898. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| All ASBMB Journals | Journal of Biological Chemistry |
| Molecular and Cellular Proteomics | ASBMB Today |