Title

A novel multiprotein complex is required to generate the prechylomicron transport vesicle from intestinal ER

Authors

Authors

S. Siddiqi; U. Saleem; N. A. Abumrad; N. O. Davidson; J. Storch; S. A. Siddiqi;C. M. Mansbach

Comments

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Abbreviated Journal Title

J. Lipid Res.

Keywords

chylomicron; lipid absorption; vesicle budding complex; CD36; L-FABP; ACID-BINDING PROTEINS; CHAIN FATTY-ACIDS; ENDOPLASMIC-RETICULUM; VESICULAR TRANSPORT; CHOLESTEROL UPTAKE; MEMBRANE-PROTEIN; EPITHELIAL-CELLS; CARGO SELECTION; PLASMA-MEMBRANE; KNOCKOUT MICE; Biochemistry & Molecular Biology

Abstract

Dietary lipid absorption is dependent on chylomicron production whose rate-limiting step across the intestinal absorptive cell is the exit of chylomicrons from the endoplasmic reticulum (ER) in its ER-to-Golgi transport vesicle, the prechylomicron transport vesicle (PCTV). This study addresses the composition of the budding complex for PCTV. Immunoprecipitation (IP) studies from rat intestinal ER solubilized in Triton X-100 suggested that vesicle-associated membrane protein 7 (VAMP7), apolipoprotein B48 (apoB48), liver fatty acid-binding protein (L-FABP), CD36, and the COPII proteins were associated on incubation of the ER with cytosol and ATP. This association was confirmed by chromatography of the solubilized ER over Sephacryl S400-HR in which these constituents cochromatographed with an apparent kDa of 630. No multiprotein complex was detected when the ER was chromatographed in the absence of PCTV budding activity (resting ER or PKC zeta depletion of ER and cytosol). Treatment of the ER with anti-apoB48 or anti-VAMP7 antibodies or using gene disrupted L-FABP or CD36 mice all significantly inhibited PCTV generation. A smaller complex (no COPII proteins) was formed when only rL-FABP was used to bud PCTV. jlr The data support the conclusion that the PCTV budding complex in intestinal ER is composed of VAMP7, apoB48, CD36, and L-FABP, plus the COPII proteins.-Siddiqi, S., U. Saleem, N. Abumrad, N. Davidson, J. Storch, S. A. Siddiqi, and C. M. Mansbach II. A novel multiprotein complex is required to generate the prechylomicron transport vesicle from intestinal ER. J. Lipid Res. 2010. 51: 1918-1928.

Journal Title

Journal of Lipid Research

Volume

51

Issue/Number

7

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

1918

Last Page

1928

WOS Identifier

WOS:000278628700028

ISSN

0022-2275

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