Inhibition of translocation of nascent apolipoprotein B across the endoplasmic reticulum membrane is associated with selective inhibition of the synthesis of apolipoprotein B

Meihui Pan, Jun Shan Liang, Edward A. Fisher, Henry N. Ginsberg

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

In HepG2 cells, inhibition of apolipoprotein B100 (apoB) translocation across the endoplasmic reticulum by an microsomal triglyceride transfer protein (MTP) inhibitor (CP-10447) in the presence of N-acetyl-leucinyl-norleucinal, a proteasomal inhibitor, results in accumulation of newly synthesized apoB in the translocation channel. Here we demonstrated that such accumulation led to a specific reduction of apoB synthesis. ApoB mRNA levels remained unchanged, but we observed reduced rates of elongation of nascent apoB in puromycin-synchronized cells pretreated with MTP inhibitor. This observation was consistent with a longer half-ribosome transit time for the synthesis of apoB in MTP-inhibited cells. Initiation of translation of apoB mRNA was not impaired by MTP inhibition. Overall, these findings suggest that translocation arrest of apoB in the endoplasmic reticulum channel can exert a selective and negative effect on the synthesis of apoB at the stage of elongation.

Original languageEnglish
Pages (from-to)27399-27405
Number of pages7
JournalJournal of Biological Chemistry
Volume275
Issue number35
DOIs
StatePublished - 1 Sep 2000

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