Authors

S. Siddiqi; S. A. Siddiqi;C. M. Mansbach

Comments

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Abbreviated Journal Title

J. Lipid Res.

Keywords

lipid absorption; transport vesicles; triacylglycerol; chylomicron; ENDOPLASMIC-RETICULUM; INTRACELLULAR-TRANSPORT; COPII VESICLES; SAR1; GTPASE; EXIT SITES; CARGO; COAT; BINDING; PROTEIN; ER; Biochemistry & Molecular Biology

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-derived vesicles (average diameter 250 nm), do not require GTP and COPII proteins for their formation, and utilize VAMP7 as a v-N-ethylmaleimide sensitive factor attachment protein receptor (SNARE). However, PCTV require COPII proteins for their fusion with the Golgi, suggesting a role for them in Golgi target recognition. In support of this, PCTV contained each of the five COPII proteins when docked with the Golgi. When PCTV were fused with the Golgi, the COPII proteins were present in greatly diminished amounts, indicating they had cycled back to the cytosol. Immuno-depletion of Sec31 from the cytosol did not affect PCTV-Golgi docking, but depletion of Sec23 resulted in a 25% decrease. Immuno-depletion of Sec24C caused a nearly complete cessation of PCTV docking activity, but on the addition of recombinant Sec24C, docking activity was restored. We conclude that the COPII proteins are present at docking of PCTV with the Golgi and that Sec24C is required for this event. Sec23 plays a less important role.-Siddiqi, S., S. A. Siddiqi, and C. M. Mansbach II. Sec24C is required for docking the prechylomicron transport vesicle with the Golgi. J. Lipid Res. 2010. 51: 1093-1100.

Journal Title

Journal of Lipid Research

Volume

51

Issue/Number

5

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

1093

Last Page

1100

WOS Identifier

WOS:000276633100025

ISSN

0022-2275

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