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) All Versions of this Article: M400296-JLR200v1 46/1/104    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services 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 Stillemark-Billton, P. Articles by Olofsson, S.-O. Search for Related Content PubMed PubMed Citation Articles by Stillemark-Billton, P. Articles by Olofsson, S.-O. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol. 46, 104-114, January 2005
Copyright © 2005 by American Society for Biochemistry and Molecular Biology

Relation of the size and intracellular sorting of apoB to the formation of VLDL 1 and VLDL 2

Pia Stillemark-Billton¹, Caroline Beck¹, Jan Borén and Sven-Olof Olofsson²

Department of Medical Biochemistry and the Wallenberg Laboratory for Cardiovascular Research, University of Göteborg, Göteborg, Sweden

² To whom correspondence should be addressed. e-mail: sven-olof.olofsson{at}wlab.gu.se

In this study, we tested the hypothesis that two separate pathways, the two-step process and an apolipoprotein B (apoB) size-dependent lipidation process, give rise to different lipoproteins. Expression of apoB-100 and C-terminally truncated forms of apoB-100 in McA-RH7777 cells demonstrated that VLDL particles can be assembled by apoB size-dependent linear lipidation, resulting in particles whose density is inversely related to the size of apoB. This lipidation results in a LDL-VLDL 2 particle containing apoB-100. VLDL 1 is assembled by the two-step process by apoB-48 and larger forms of apoB but not to any significant amount by apoB-41. The major amount of intracellular apoB-80 and apoB-100 banded with a mean density of 1.10 g/ml. Its formation was dependent on the sequence between apoB-72 and apoB-90. This dense particle, which is retained in the cell, possibly by chaperones or association with the microsomal membrane, is a precursor of secreted VLDL 1. The intracellular LDL-VLDL 2 particles formed during size-dependent lipidation appear to be the precursors of intracellular VLDL 1.

We propose that the dense apoB-100 intracellular particle is converted to LDL-VLDL 2 by size-dependent lipidation. LDL-VLDL 2 is secreted or converted to VLDL 1 by the uptake of the major amount of triglycerides.

Abbreviations: apoB, apolipoprotein B; BiP, binding protein; GRP94, glucose regulatory protein 94; LDLR, low density lipoprotein receptor; MTP, microsomal triglyceride transfer protein; PDI, protein disulfide isomerase

Supplementary key words chaperones • microsomal triglyceride transfer protein • intracellular retention • apolipoprotein B • very low density lipoprotein

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

This article has been cited by other articles:

				M. Adiels, S.-O. Olofsson, M.-R. Taskinen, and J. Boren Overproduction of Very Low-Density Lipoproteins Is the Hallmark of the Dyslipidemia in the Metabolic Syndrome Arterioscler. Thromb. Vasc. Biol., July 1, 2008; 28(7): 1225 - 1236. [Abstract] [Full Text] [PDF]

				N. Dashti, M. Manchekar, Y. Liu, Z. Sun, and J. P. Segrest Microsomal Triglyceride Transfer Protein Activity Is Not Required for the Initiation of Apolipoprotein B-containing Lipoprotein Assembly in McA-RH7777 Cells J. Biol. Chem., September 28, 2007; 282(39): 28597 - 28608. [Abstract] [Full Text] [PDF]

				M. M. W. Smolenaars, O. Madsen, K. W. Rodenburg, and D. J. Van der Horst Molecular diversity and evolution of the large lipid transfer protein superfamily J. Lipid Res., March 1, 2007; 48(3): 489 - 502. [Abstract] [Full Text] [PDF]

				B. Magnusson, L. Asp, P. Bostrom, M. Ruiz, P. Stillemark-Billton, D. Linden, J. Boren, and S.-O. Olofsson Adipocyte Differentiation-Related Protein Promotes Fatty Acid Storage in Cytosolic Triglycerides and Inhibits Secretion of Very Low-Density Lipoproteins Arterioscler. Thromb. Vasc. Biol., July 1, 2006; 26(7): 1566 - 1571. [Abstract] [Full Text] [PDF]

				L. Li, P. Stillemark-Billton, C. Beck, P. Bostrom, L. Andersson, M. Rutberg, J. Ericsson, B. Magnusson, D. Marchesan, A. Ljungberg, et al. Epigallocatechin gallate increases the formation of cytosolic lipid droplets and decreases the secretion of apoB-100 VLDL J. Lipid Res., January 1, 2006; 47(1): 67 - 77. [Abstract] [Full Text] [PDF]

				S.-O. Olofsson ApoA-V: The Regulation of a Regulator of Plasma Triglycerides Arterioscler. Thromb. Vasc. Biol., June 1, 2005; 25(6): 1097 - 1099. [Full Text] [PDF]

				L. Asp, B. Magnusson, M. Rutberg, L. Li, J. Boren, and S.-O. Olofsson Role of ADP Ribosylation Factor 1 in the Assembly and Secretion of ApoB-100-Containing Lipoproteins Arterioscler. Thromb. Vasc. Biol., March 1, 2005; 25(3): 566 - 570. [Abstract] [Full Text] [PDF]