Abstract：
: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 [(35)S]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 approximately 7.5 nm. These and additional data suggested that approximately 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.
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Chisholm JW,Burleson ER,Shelness GS,Parks JSkeywords:
subject
Has Abstractpub_date
2002-01-01 00:00:00pages
36-44issue
1eissn
0022-2275issn
1539-7262journal_volume
43pub_type
杂志文章abstract：:The storage of lipids in the form of triglycerides (TGs) and the de novo synthesis (lipogenesis) of fatty acids from nonlipid precursors [de novo lipogenesis (DNL)] are important functions of adipose tissue (AT) that influence whole-body metabolism. Yet, few studies have reported in vivo estimates of adipose lipid kin...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.P082628
更新日期：2018-09-01 00:00:00
abstract：:The regulation of hepatic and intestinal 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase and acyl-CoA; cholesterol acyltransferase (ACAT) activities by dietary fish oil was examined in the rabbit. Rabbits were fed 10% menhaden oil or menhaden oil plus 1% cholesterol for 14 days. They were compared with animals fed ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1987-01-01 00:00:00
abstract：:The acute-phase response (APR) leads to alterations in lipid metabolism and type II nuclear hormone receptors, which regulate lipid metabolism, are suppressed, in liver, heart, and kidney. Here, we examine the effect of the APR in adipose tissue. In mice, lipopolysaccharide produces a rapid, marked decrease in mRNA le...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500540-JLR200
更新日期：2006-10-01 00:00:00
abstract：:Three aliphatic tricarboxylic acids have been found in rat urine. They have been identified as 6-carboxy-5-undecenedioic acid, 6-carboxy-5-dodecenedoic acid, and 6-carboxy-5-tridecenedioic acid. The carbon skeleton structure was determined by mass spectra of the hydrogenated methyl esters. The double bond position was...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1976-11-01 00:00:00
abstract：:N-3 trans geometrical isomers of 20:5 n-3 and 22:6 n-3 were isolated from rats fed heated linseed oil. The ability of these acids to inhibit 20:4 n-6 metabolism by human platelets was examined. The concentrations required to inhibit 50% of platelet aggregation (IC50) induced by 2.5 microM 20:4 n-6 were higher for the ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-07-01 00:00:00
abstract：:Familial hypobetalipoproteinemia, a syndrome associated with low plasma cholesterol levels, can be caused by apoB gene mutations. We identified a healthy 42-year-old man whose total plasma cholesterol level was 80 mg/dl. His plasma very low density lipoprotein (VLDL) contained a unique truncated apoB species, apoB-83,...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1992-04-01 00:00:00
abstract：:Structurally specific very low density lipoprotein (VLDL) particles are presumed to redirect VLDL uptake during yolk deposition. Egg production is an energy intensive process, but energy excess negatively affects egg production. This study sought to determine whether overfeeding changed hen lipoprotein profiles, and i...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1994-08-01 00:00:00
abstract：:Apolipoprotein L is a newly recognized component of human plasma lipoproteins. Mainly associated with apoA-I-containing lipoproteins, it is a marker of distinct HDL subpopulations. In an effort to gain inference as to its as yet unknown function, we studied biological determinants of apoL levels in human plasma. The d...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：2000-08-01 00:00:00
abstract：:In mammals, the esterification of sterols by ACAT plays a critical role in eukaryotic lipid homeostasis. Using the predominant isoform of the yeast ACAT-related enzyme family, Are2p, as a model, we targeted phylogenetically conserved sequences for mutagenesis in order to identify functionally important motifs. Deletio...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：2001-08-01 00:00:00
abstract：:Our goal was to further define the role of LPL gene polymorphisms in coronary heart disease (CHD) risk. We determined the frequencies of three LPL polymorphisms (D9N, N291S, and S447X) in 899 men from the Veterans Affairs HDL Intervention Trial (VA-HIT), a study that examined the potential benefits of increasing HDL w...
journal_title：Journal of lipid research
pub_type： 临床试验,杂志文章
doi：10.1194/jlr.M400152-JLR200
更新日期：2004-10-01 00:00:00
abstract：:Acyl-CoA-dependent O-acyltransferases catalyze reactions in which fatty acyl-CoAs are joined to acyl acceptors containing free hydroxyl groups to produce neutral lipids. In this report, we characterize a human multifunctional O-acyltransferase (designated MFAT) that belongs to the acyl-CoA:diacylglycerol acyltransfera...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500168-JLR200
更新日期：2005-11-01 00:00:00
abstract：:We have performed plasma lipid profiling using liquid chromatography electrospray ionization tandem mass spectrometry on a population cohort of more than 1,000 individuals. From 10 μl of plasma we were able to acquire comparative measures of 312 lipids across 23 lipid classes and subclasses including sphingolipids, ph...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.P035808
更新日期：2013-10-01 00:00:00
abstract：:Recent discovery and characterization of APOAV suggests a role in metabolism of triglyceride (TG)-rich lipoproteins. Previously, variation at the APOAV locus was shown to modestly influence plasma TGs in normolipidemic samples. The aims of this study were to assess the effects of a polymorphism in APOAV (T-1131C) in t...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M200480-JLR200
更新日期：2003-06-01 00:00:00
abstract：:It was the aim of this study to i) compare the effects of glucose and other hexoses with that of oleate on secretion of apolipoproteins (apos) A-I and B by HepG2 cells, and ii) document the effect of various metabolic inhibitors on the secretion of these apos in the absence or presence of extra glucose/oleate. i) The ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1995-08-01 00:00:00
abstract：:This article presents a novel methodology for the analysis of ethanolamine glycerophospholipid (PE) and lysoPE molecular species directly from lipid extracts of biological samples. Through brief treatment of lipid extracts with fluorenylmethoxylcarbonyl (Fmoc) chloride, PE and lysoPE species were selectively derivatiz...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D500007-JLR200
更新日期：2005-07-01 00:00:00
abstract：:LDL-associated phospholipids (PLs) may be transferred into platelets. In this work, we characterized the role of VLDLs as PL donors. VLDL transferred radiolabeled PLs to platelets in a temperature- and concentration-dependent manner. LPL stimulated this process through its action on VLDL lipolysis, because it was abol...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500209-JLR200
更新日期：2006-02-01 00:00:00
abstract：:Extracts of urine and serum from children with cholestatic liver disease were analyzed by fast atom bombardment (FAB) mass spectrometry. About half of all spectra showed a peak at m/z 657, compatible with the presence of a glucuronidated cholestenediol sulfate. Separation by ion exchange chromatography before and afte...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1997-05-01 00:00:00
abstract：:The facile synthesis of lithocholic acids sulfates by a procedure that produced the desired products in over 90% yield is described. Lithocholic acid sulfate and glycolithocholic acid sulfate were synthesized by reacting lithocholic acid or glycolithocholic acid with sulfur trioxide-triethylamine complex in dimethylfo...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1977-07-01 00:00:00
abstract：:Several recent reports have examined whether there is a correlation between the presence of some minor alleles of the highly polymorphic apolipoprotein B gene and atherosclerosis and premature heart disease. The present study extends this investigation. A high-resolution method was used to study the allele frequencies...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-04-01 00:00:00
abstract：:Liver and kidney microsomes have been found to catalyze a rapid decarboxylation of retinoic acid in vitro. The reaction requires NADPH and Fe(2+), and is further stimulated by the presence of pyrophosphate. Thiamine pyrophosphate contained sufficient iron as an impurity to provide strong enhancement of the reaction in...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1968-07-01 00:00:00
abstract：:The objective of this study was to establish a new lipoprotein lipase (LPL) and hepatic lipase (HL) activity assay method. Seventy normal volunteers were recruited. Lipase activities were assayed by measuring the increase in absorbance at 546 nm due to the quinoneine dye. Reaction mixture-1 (R-1) contained dioleoylgly...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M700528-JLR200
更新日期：2008-07-01 00:00:00
abstract：:Previous studies have reported both positive and negative effects of culture of islets at high glucose concentrations on regulated insulin secretion. Here, we have reexamined this question in mouse islets and determined the role of changes in lipid synthesis in the effects of glucose. Glucose-stimulated insulin secret...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M700533-JLR200
更新日期：2008-04-01 00:00:00
abstract：:Scavenger receptor class B type I (SR-BI) has been identified as a functional HDL binding protein that can mediate the selective uptake of cholesteryl ester (CE) from HDL. To quantify the in vivo role of SR-BI in the process of selective uptake, HDL was labeled with cholesteryl ether ([(3)H] CEt-HDL) and (125)I-tyrami...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M400191-JLR200
更新日期：2004-11-01 00:00:00
abstract：:Purified liver plasma membranes were prepared from rats fed a high-fat, carbohydrate-free diet or a high-glucose, fat-free diet. Membranes from rats fed the high-fat diet bound significantly less 125I-labeled concanavalin A (Con A) than did those from rats fed the fat-free diets. The magnitude of the binding differenc...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1979-07-01 00:00:00
abstract：:The rate-limiting step in the transit of dietary fat across the intestinal absorptive cell is its exit from the endoplasmic reticulum (ER) in a specialized ER-to-Golgi transport vesicle, the prechylomicron transport vesicle (PCTV). PCTV bud off from the ER membranes and have unique features; they are the largest ER-de...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M002758
更新日期：2010-05-01 00:00:00
abstract：:The extent of oxidoreduction of the 3 alpha-, 7 alpha- and 12 alpha-hydroxyl groups in bile acids during the enterohepatic circulation in man was studied with the use of [3 beta-3H]-labeled deoxycholic acid and cholic acid, [7 beta-3H]-labeled cholic acid, and [12 beta-3H]-labeled deoxycholic acid and cholic acid. Eac...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1986-02-01 00:00:00
abstract：:Niemann-Pick disease, type C (NP-C), often associated with Niemann-Pick disease, type C1 (NPC1) mutations, is a cholesterol-storage disorder characterized by cellular lipid accumulation, neurodegeneration, and reduced steroid production. To study NPC1 function in vivo, we cloned zebrafish npc1 and analyzed its gene ex...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M012377
更新日期：2011-07-01 00:00:00
abstract：:Zinc Finger Protein 202 (ZNF202) is a transcriptional repressor that binds elements found predominantly in genes involved in HDL metabolism. We tested the following hypotheses: 1) frequencies of single-nucleotide polymorphisms (SNPs) and haplotypes in ZNF202 differ between individuals with low and high HDL cholesterol...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500521-JLR200
更新日期：2006-05-01 00:00:00
abstract：:A group of polyunsaturated fatty acids called conjugated linoleic acids (CLAs) are found in ruminant products, where the most common isomers are cis9, trans11 (c 9,t11) and trans10, cis12 (t10,c12) CLA. A crude mixture of these isomers has been shown in animal studies to alter body composition by a reduction in body f...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M300120-JLR200
更新日期：2003-08-01 00:00:00
abstract：:We measured the amount of apoA-I in serum by isotope dilution, finding 1.33 mg/ml (standard deviation 0.177) in six normolipidemic, healthy subjects. We developed this method by adapting published techniques to purify apoA-I from 3 ml of serum in two steps: density gradient ultracentrifugation and high performance liq...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1988-01-01 00:00:00
