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Titolo:
Recycling of apolipoprotein E in mouse liver
Autore:
Fazio, S; Linton, MF; Hasty, AH; Swift, LL;
Indirizzi:
Vanderbiltlle,v, Ctr Med, Div Endocrinol & Diabet,Sch Med, Dept Med, Nashvi Vanderbilt Univ Nashville TN USA 37232 & Diabet,Sch Med, Dept Med, Nashvi Vanderbilt Univ, Dept Pathol, Sch Med, Nashville, TN 37232 USA Vanderbilt Univ Nashville TN USA 37232 , Sch Med, Nashville, TN 37232 USA Vanderbilt Univ, Dept Pharmacol, Sch Med, Nashville, TN 37232 USA Vanderbilt Univ Nashville TN USA 37232 , Sch Med, Nashville, TN 37232 USA
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 12, volume: 274, anno: 1999,
pagine: 8247 - 8253
SICI:
0021-9258(19990319)274:12<8247:ROAEIM>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
RECEPTOR-MEDIATED ENDOCYTOSIS; HEPARAN-SULFATE PROTEOGLYCANS; BONE-MARROW TRANSPLANTATION; E-DEFICIENT MICE; LIPOPROTEIN RECEPTOR; PERITONEAL-MACROPHAGES; GOLGI-APPARATUS; HEPATIC GOLGI; APOPROTEIN-E; BETA-VLDL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Fazio, S VanderbiltBUniv, Ctr Med, Div Endocrinol & Diabet,Sch Med, Dept Med, 715 MR Vanderbilt Univ 715 MRB 2 Nashville TN USA 37232 Dept Med, 715 MR
Citazione:
S. Fazio et al., "Recycling of apolipoprotein E in mouse liver", J BIOL CHEM, 274(12), 1999, pp. 8247-8253

Abstract

Following the internalization of low density lipoprotein (LDL) by the LDL receptor within cells, both the lipid and the protein components of LDL arecompletely degraded within the lysosomes, Remnant lipoproteins are also internalized by cells via the LDL receptor as well as other receptors, but the events following the internalization of these complexes, which use apolipoprotein E (apoE) as their ligand for receptor capture, have not been defined. There is evidence that apoE-containing beta-very low density lipoproteins follow differential intracellular routing depending on their size and apoE content and that apoE internalized with lipoproteins can be resecreted by cultured hepatocytes and fibroblasts, In the present studies, we addressed the question of apoE sparing or recycling as a physiologic phenomenon. Remnant lipoproteins (d < 1.019 g/ml) from normal mouse plasma were iodinatedand injected into normal C57BL/6 mice. Livers were collected at 10, 30, 60, and 120 min after injection, and hepatic Golgi fractions were prepared for gel electrophoresis analysis. Golgi preparations were analyzed for galactosyltransferase enrichment (>40-fold above cell homogenate) and by appearance of the Gels stacks and vesicles on electron microscopy, Iodinated apoE was consistently found in the Golgi fractions peaking at 10 min and disappearing by 2 h after injection. Although traces of apoB48 were present in the Golgi fractions, the apoE/apoB ratio in the Golgi was 50-fold higher compared with serum. Quantitatively similar results were obtained when the very low density lipoprotein remnants were injected into mice deficient in eitherapoE or the LDL receptor, indicating that the phenomenon of apoE recyclingis not influenced by the production of endogenous apoE and is not dependent on the presence of LDL receptors, In addition, radioactive apoE in the Golgi fractions was part of d = 1.019-1.21 g/ml complexes, indicating an association of recycled apoE with either newly formed lipoproteins or the internalized complexes. These studies show that apoE recycling is a physiologic phenomenon in vivo and establish the presence of a unique pathway of intracellular processing of apoE-containing remnant lipoproteins.

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Documento generato il 27/11/20 alle ore 16:13:28