HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chisholm, J. W. Articles by Parks, J. S. Search for Related Content PubMed PubMed Citation Articles by Chisholm, J. W. Articles by Parks, J. S. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol. 43, 36-44, January 2002
Copyright © 2002 by Lipid Research, Inc.

ApoA-I secretion from HepG2 cells: evidence for the secretion of both lipid-poor apoA-I and intracellularly assembled nascent HDL

Correspondence to: John S. Parks, To whom correspondence should be addressed., jparks{at}wfubmc.edu (E-mail)

The goal of this study was to determine whether apolipoprotein A-I (apoA-I) is lipidated before secretion by HepG2 cells. ApoA-I was extracted from microsomes after radiolabeling with [³⁵S]Met/Cys. After ultracentrifugal flotation, d < 1.25 g/ml and d > 1.25 g/ml fractions were immunoprecipitated and analyzed by SDS-PAGE. Under steady state radiolabeling conditions, 20% of extracted microsomal apoA-I floated at d < 1.25 g/ml. Pulse-chase experiments demonstrated that the percentage of microsomal apoA-I associated with lipid peaked between 2 and 8 min postsynthesis. Density gradient ultracentrifugation, and nondenaturing gradient gel electrophoresis of HepG2 cell medium, indicated that 50% of secretory apoA-I existed as small HDL particles with a diameter of 7.5 nm. These and additional data suggested that 20% of newly secreted apoA-I is lipidated intracellularly and another 30% is secreted in lipid-free or lipid-poor form but acquires sufficient lipid to become small HDL within 1 h of secretion, with little further maturation over the time course of the incubation (2 h).

These results indicate that a process exists for the presecretory intracellular assembly of apoA-I with lipid in HepG2 cells and that apoA-I is secreted in both lipid-poor and lipidated forms. — Chisholm, J. W., E. R. Burleson, G. S. Shelness, and J. S. Parks. ApoA-I secretion from HepG2 cells: evidence for the secretion of both lipid-poor apoA-I and intracellularly assembled nascent HDL. J. Lipid Res. 2002. 43: 36–44.

Supplementary key words: apolipoprotein A-I, carbonate extraction, HDL metabolism, HDL secretion, HDL biosynthesis, human, lipid-free apoA-I, lipid-poor apoA-I, ultracentrifugation

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				A. Mulya, J.-Y. Lee, A. K. Gebre, E. Y. Boudyguina, S.-K. Chung, T. L. Smith, P. L. Colvin, X.-C. Jiang, and J. S. Parks Initial interaction of apoA-I with ABCA1 impacts in vivo metabolic fate of nascent HDL J. Lipid Res., November 1, 2008; 49(11): 2390 - 2401. [Abstract] [Full Text] [PDF]

				A. Mulya, J.-Y. Lee, A. K. Gebre, M. J. Thomas, P. L. Colvin, and J. S. Parks Minimal Lipidation of Pre-{beta} HDL by ABCA1 Results in Reduced Ability to Interact with ABCA1 Arterioscler. Thromb. Vasc. Biol., August 1, 2007; 27(8): 1828 - 1836. [Abstract] [Full Text] [PDF]

				P. G. Yancey, H. Yu, M. F. Linton, and S. Fazio A Pathway-Dependent on ApoE, ApoAI, and ABCA1 Determines Formation of Buoyant High-Density Lipoprotein by Macrophage Foam Cells Arterioscler. Thromb. Vasc. Biol., May 1, 2007; 27(5): 1123 - 1131. [Abstract] [Full Text] [PDF]

				J. Grove, T. Huby, Z. Stamataki, T. Vanwolleghem, P. Meuleman, M. Farquhar, A. Schwarz, M. Moreau, J. S. Owen, G. Leroux-Roels, et al. Scavenger Receptor BI and BII Expression Levels Modulate Hepatitis C Virus Infectivity J. Virol., April 1, 2007; 81(7): 3162 - 3169. [Abstract] [Full Text] [PDF]

				M. Dreux, T. Pietschmann, C. Granier, C. Voisset, S. Ricard-Blum, P.-E. Mangeot, Z. Keck, S. Foung, N. Vu-Dac, J. Dubuisson, et al. High Density Lipoprotein Inhibits Hepatitis C Virus-neutralizing Antibodies by Stimulating Cell Entry via Activation of the Scavenger Receptor BI J. Biol. Chem., July 7, 2006; 281(27): 18285 - 18295. [Abstract] [Full Text] [PDF]

				S. Yokoyama Assembly of High-Density Lipoprotein Arterioscler. Thromb. Vasc. Biol., January 1, 2006; 26(1): 20 - 27. [Abstract] [Full Text] [PDF]

				J. Maric, R. S. Kiss, V. Franklin, and Y. L. Marcel Intracellular Lipidation of Newly Synthesized Apolipoprotein A-I in Primary Murine Hepatocytes J. Biol. Chem., December 2, 2005; 280(48): 39942 - 39949. [Abstract] [Full Text] [PDF]

				L. Krimbou, H. Hajj Hassan, S. Blain, S. Rashid, M. Denis, M. Marcil, and J. Genest Biogenesis and speciation of nascent apoA-I-containing particles in various cell lines J. Lipid Res., August 1, 2005; 46(8): 1668 - 1677. [Abstract] [Full Text] [PDF]

				H. Zheng, R. S. Kiss, V. Franklin, M.-D. Wang, B. Haidar, and Y. L. Marcel ApoA-I Lipidation in Primary Mouse Hepatocytes: SEPARATE CONTROLS FOR PHOSPHOLIPID AND CHOLESTEROL TRANSFERS J. Biol. Chem., June 3, 2005; 280(22): 21612 - 21621. [Abstract] [Full Text] [PDF]

				M. Tsujita, C.-A. Wu, S. Abe-Dohmae, S. Usui, M. Okazaki, and S. Yokoyama On the hepatic mechanism of HDL assembly by the ABCA1/apoA-I pathway J. Lipid Res., January 1, 2005; 46(1): 154 - 162. [Abstract] [Full Text] [PDF]

				S. Bhat, M. Zabalawi, M. C. Willingham, G. S. Shelness, M. J. Thomas, and M. G. Sorci-Thomas Quality control in the apoA-I secretory pathway: deletion of apoA-I helix 6 leads to the formation of cytosolic phospholipid inclusions J. Lipid Res., July 1, 2004; 45(7): 1207 - 1220. [Abstract] [Full Text] [PDF]

				D. Sahoo, T. C. Trischuk, T. Chan, V. A. B. Drover, S. Ho, G. Chimini, L. B. Agellon, R. Agnihotri, G. A. Francis, and R. Lehner ABCA1-dependent lipid efflux to apolipoprotein A-I mediates HDL particle formation and decreases VLDL secretion from murine hepatocytes J. Lipid Res., June 1, 2004; 45(6): 1122 - 1131. [Abstract] [Full Text] [PDF]

				J.-Y. Lee, L. Lanningham-Foster, E. Y. Boudyguina, T. L. Smith, E. R. Young, P. L. Colvin, M. J. Thomas, and J. S. Parks Pre{beta} high density lipoprotein has two metabolic fates in human apolipoprotein A-I transgenic mice J. Lipid Res., April 1, 2004; 45(4): 716 - 728. [Abstract] [Full Text] [PDF]

				R. S. Kiss, D. C. McManus, V. Franklin, W. L. Tan, A. McKenzie, G. Chimini, and Y. L. Marcel The Lipidation by Hepatocytes of Human Apolipoprotein A-I Occurs by Both ABCA1-dependent and -independent Pathways J. Biol. Chem., March 14, 2003; 278(12): 10119 - 10127. [Abstract] [Full Text] [PDF]

				U. Panzenboeck, Z. Balazs, A. Sovic, A. Hrzenjak, S. Levak-Frank, A. Wintersperger, E. Malle, and W. Sattler ABCA1 and Scavenger Receptor Class B, Type I, Are Modulators of Reverse Sterol Transport at an in Vitro Blood-Brain Barrier Constituted of Porcine Brain Capillary Endothelial Cells J. Biol. Chem., November 1, 2002; 277(45): 42781 - 42789. [Abstract] [Full Text] [PDF]

				B. G. Brown, M. C. Cheung, A. C. Lee, X.-Q. Zhao, and A. Chait Antioxidant Vitamins and Lipid Therapy: End of a Long Romance? Arterioscler. Thromb. Vasc. Biol., October 1, 2002; 22(10): 1535 - 1546. [Abstract] [Full Text] [PDF]