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Titolo:
Identification of domains in apolipoprotein B100 that confer a high requirement for the microsomal triglyceride transfer protein
Autore:
Nicodeme, E; Benoist, F; McLeod, R; Yao, ZM; Scott, J; Shoulders, CC; Grand-Perret, T;
Indirizzi:
Lab Glaxo Wellcome, Ctr Rech, F-91951 Les Ulis, France Lab Glaxo WellcomeLes Ulis France F-91951 ech, F-91951 Les Ulis, France Univ Ottawa, Inst Heart, Lipoprot & Atherosclerosis Grp, Ottawa Civic Hosp, Univ Ottawa Ottawa ON Canada K1Y 4E9 erosclerosis Grp, Ottawa Civic Hosp, Univ,London Imperial Coll Sci Technol & Med, Ctr Clin Sci, MRC, Mol Med Grp Univ London Imperial Coll Sci Technol & Med London England W12 0NN d Grp
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 4, volume: 274, anno: 1999,
pagine: 1986 - 1993
SICI:
0021-9258(19990122)274:4<1986:IODIAB>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-DENSITY LIPOPROTEINS; B-CONTAINING LIPOPROTEINS; HEPG2 CELLS; ENDOPLASMIC-RETICULUM; IMMUNOELECTRON MICROSCOPY; LIPID RECRUITMENT; MCA-RH7777 CELLS; HEPATOMA-CELLS; MESSENGER-RNA; SECRETION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Grand-Perret, T Labs,laxo Wellcome, Ctr Rech, 25 Ave Quebec,ZA Courtaboeuf, F-91951 Les Uli Lab Glaxo Wellcome 25 Ave Quebec,ZA Courtaboeuf Les UlisFrance F-91951
Citazione:
E. Nicodeme et al., "Identification of domains in apolipoprotein B100 that confer a high requirement for the microsomal triglyceride transfer protein", J BIOL CHEM, 274(4), 1999, pp. 1986-1993

Abstract

The microsomal triglyceride transfer protein (MTP) is required for the assembly and secretion of apoB-containing lipoproteins, To investigate the role of MTP in lipoprotein assembly, we determined the ability of carboxyl-terminally truncated forms of apoB to be secreted from cells treated with the MTP inhibitor 4'-bromo-3'-methylmetaqualone (Benoist, F., Nicodeme, E., andGrand-Ferret, T. (1996) Eur. J. Biochem. 240, 713-720). In Caco-2 and mhAT3F cells that produce apoB100 and apoB48, the inhibitor preferentially blocked apoB100 secretion. When the inhibitor was tested on McARH7777 cells stably transfected with cDNAs encoding human apoB100, apoB72, apoB53, apoB29, and apoB18, the secretion of apoB100, apoB72, and apoB53 was preferentiallyimpaired relative to apoB48 and shorter forms. To delineate the region between apoB48 and apoB53 that has a high requirement for MTP, we used puromycin to generate a range of truncated forms of apoB in HepG2 cells. The secretion of apoB53 and longer forms of apoB was markedly affected by low concentrations of the MTP inhibitor (similar to 1 mu M), whereas apoB51 and smaller forms of apoB were only affected at higher concentrations (> 10 mu M). The size-related sensitivity to MTP inhibitor was not due to late processingor retention, since the same result was observed when nascent lipoproteinswere isolated from the endoplasmic reticulum. The MTP inhibitor did not alter the density of the secreted lipoproteins, indicating that each apoB polypeptide requires a minimally defined amount of lipid to attain a secretable conformation, Our results suggest that the folding of the domain between apoB51 and apoB53 has a high requirement for lipid, This domain is predicted to form amphipathic alpha-helices and to bind lipid reversibly, It proceeds and is followed by rigid amphipathic beta-sheets that are predicted to associate with lipid irreversibly, We speculate that these domains enable apoB to switch from a stable lipid-poor conformation in apoB48 to another lipid-rich conformation in apoB100 during lipoprotein assembly.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/09/20 alle ore 05:03:44