Hepatic apolipoprotein J is secreted as a lipoprotein.

Apolipoprotein J (apoJ) is a unique glycoprotein thought to be involved in a variety of physiological processes, including lipid transport, regulation of complement function, sperm maturation, programmed cell death, and membrane recycling. In the plasma, apoJ is associated with apoA-I in high and ve...

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Main Authors: BF Burkey, WD Stuart, JA Harmony
Format: Article
Language:English
Published: Elsevier 1992-10-01
Series:Journal of Lipid Research
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520414063
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spelling doaj-ee9025e250b54ab8b489aa103361f28d2021-04-26T05:52:28ZengElsevierJournal of Lipid Research0022-22751992-10-01331015171526Hepatic apolipoprotein J is secreted as a lipoprotein.BF Burkey0WD Stuart1JA Harmony2Developmental Biology Program, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0575.Developmental Biology Program, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0575.Developmental Biology Program, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0575.Apolipoprotein J (apoJ) is a unique glycoprotein thought to be involved in a variety of physiological processes, including lipid transport, regulation of complement function, sperm maturation, programmed cell death, and membrane recycling. In the plasma, apoJ is associated with apoA-I in high and very high density lipoproteins. In this report we demonstrate that HepG2 human hepatocellular carcinoma cells secrete apoJ in association with a significant amount of lipid, providing unequivocal evidence that apoJ can transport lipids. The HepG2 cell line has provided important clues about the structural organization of nascent lipoprotein particles. HepG2 cell apoJ-containing lipoproteins are dense and heterogenous in size, ranging from 100 to 910 kDa. Plasma and HepG2 cell apoJ-lipoproteins differ in size distribution. Both have alpha 2 electrophoretic mobility, although their average mobilities differ within the alpha 2 region. In contrast to plasma apoJ-HDL which contain little triglyceride and which can associate with apoA-I, HepG2 cell apoJ-lipoproteins are rich in triglyceride and lack apoA-I. By implication, nascent apoJ-lipoproteins undergo plasma remodeling that results in triglyceride depletion and apoA-I association. We propose that the metabolic consequences of this remodeling play an important role in lipid homeostasis in localized tissue environments, particularly where organs are isolated from the blood by cellular barriers such as in testis and brain. In such tissues, apoJ is expressed constitutively in high level compared to other lipid transport proteins.http://www.sciencedirect.com/science/article/pii/S0022227520414063
collection DOAJ
language English
format Article
sources DOAJ
author BF Burkey
WD Stuart
JA Harmony
spellingShingle BF Burkey
WD Stuart
JA Harmony
Hepatic apolipoprotein J is secreted as a lipoprotein.
Journal of Lipid Research
author_facet BF Burkey
WD Stuart
JA Harmony
author_sort BF Burkey
title Hepatic apolipoprotein J is secreted as a lipoprotein.
title_short Hepatic apolipoprotein J is secreted as a lipoprotein.
title_full Hepatic apolipoprotein J is secreted as a lipoprotein.
title_fullStr Hepatic apolipoprotein J is secreted as a lipoprotein.
title_full_unstemmed Hepatic apolipoprotein J is secreted as a lipoprotein.
title_sort hepatic apolipoprotein j is secreted as a lipoprotein.
publisher Elsevier
series Journal of Lipid Research
issn 0022-2275
publishDate 1992-10-01
description Apolipoprotein J (apoJ) is a unique glycoprotein thought to be involved in a variety of physiological processes, including lipid transport, regulation of complement function, sperm maturation, programmed cell death, and membrane recycling. In the plasma, apoJ is associated with apoA-I in high and very high density lipoproteins. In this report we demonstrate that HepG2 human hepatocellular carcinoma cells secrete apoJ in association with a significant amount of lipid, providing unequivocal evidence that apoJ can transport lipids. The HepG2 cell line has provided important clues about the structural organization of nascent lipoprotein particles. HepG2 cell apoJ-containing lipoproteins are dense and heterogenous in size, ranging from 100 to 910 kDa. Plasma and HepG2 cell apoJ-lipoproteins differ in size distribution. Both have alpha 2 electrophoretic mobility, although their average mobilities differ within the alpha 2 region. In contrast to plasma apoJ-HDL which contain little triglyceride and which can associate with apoA-I, HepG2 cell apoJ-lipoproteins are rich in triglyceride and lack apoA-I. By implication, nascent apoJ-lipoproteins undergo plasma remodeling that results in triglyceride depletion and apoA-I association. We propose that the metabolic consequences of this remodeling play an important role in lipid homeostasis in localized tissue environments, particularly where organs are isolated from the blood by cellular barriers such as in testis and brain. In such tissues, apoJ is expressed constitutively in high level compared to other lipid transport proteins.
url http://www.sciencedirect.com/science/article/pii/S0022227520414063
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