MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.

Because multiple myeloma (MM) cells are at risk for endoplasmic reticulum (ER) stress, they require a carefully regulated mechanism to promote protein translation of selected transcripts when proliferation is stimulated. MAPK-interacting kinases (MNKs) may provide this mechanism by enhancing cap-dep...

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Main Authors: Yijiang Shi, Patrick Frost, Bao Hoang, Yonghui Yang, Carolyne Bardeleben, Joseph Gera, Alan Lichtenstein
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0094011&type=printable
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author Yijiang Shi
Patrick Frost
Bao Hoang
Yonghui Yang
Carolyne Bardeleben
Joseph Gera
Alan Lichtenstein
author_facet Yijiang Shi
Patrick Frost
Bao Hoang
Yonghui Yang
Carolyne Bardeleben
Joseph Gera
Alan Lichtenstein
author_sort Yijiang Shi
collection DOAJ
description Because multiple myeloma (MM) cells are at risk for endoplasmic reticulum (ER) stress, they require a carefully regulated mechanism to promote protein translation of selected transcripts when proliferation is stimulated. MAPK-interacting kinases (MNKs) may provide this mechanism by enhancing cap-dependent translation of a small number of critical transcripts. We, thus, tested whether MNKs played a role in MM responses to the myeloma growth factor interleukin-6 (IL-6). IL-6 activated MNK1 phosphorylation and induced phosphorylation of its substrate, eIF-4E, in MM lines and primary specimens. MNK paralysis, achieved pharmacologically or by shRNA, prevented MM expansion stimulated by IL-6. A phosphodefective eIF-4E mutant also prevented the IL-6 response, supporting the notion that MNK's role was via phosphorylation of eIF-4E. Both pharmacological MNK inhibition and expression of the phosphodefective eIF-4E mutant inhibited MM growth in mice. Although critical for IL-6-induced expansion, eIF-4E phosphorylation had no significant effect on global translation or Ig expression. Deep sequencing of ribosome-protected mRNAs revealed a repertoire of genes involved in metabolic processes and ER stress modulation whose translation was regulated by eIF-4E phosphorylation. These data indicate MM cells exploit the MNK/eIF-4E pathway for selective mRNA translation without enhancing global translation and risking ER stress.
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spelling doaj-art-afbb6a8ed1804a6b8aca5b065b7ec90c2025-08-20T03:00:35ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0194e9401110.1371/journal.pone.0094011MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.Yijiang ShiPatrick FrostBao HoangYonghui YangCarolyne BardelebenJoseph GeraAlan LichtensteinBecause multiple myeloma (MM) cells are at risk for endoplasmic reticulum (ER) stress, they require a carefully regulated mechanism to promote protein translation of selected transcripts when proliferation is stimulated. MAPK-interacting kinases (MNKs) may provide this mechanism by enhancing cap-dependent translation of a small number of critical transcripts. We, thus, tested whether MNKs played a role in MM responses to the myeloma growth factor interleukin-6 (IL-6). IL-6 activated MNK1 phosphorylation and induced phosphorylation of its substrate, eIF-4E, in MM lines and primary specimens. MNK paralysis, achieved pharmacologically or by shRNA, prevented MM expansion stimulated by IL-6. A phosphodefective eIF-4E mutant also prevented the IL-6 response, supporting the notion that MNK's role was via phosphorylation of eIF-4E. Both pharmacological MNK inhibition and expression of the phosphodefective eIF-4E mutant inhibited MM growth in mice. Although critical for IL-6-induced expansion, eIF-4E phosphorylation had no significant effect on global translation or Ig expression. Deep sequencing of ribosome-protected mRNAs revealed a repertoire of genes involved in metabolic processes and ER stress modulation whose translation was regulated by eIF-4E phosphorylation. These data indicate MM cells exploit the MNK/eIF-4E pathway for selective mRNA translation without enhancing global translation and risking ER stress.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0094011&type=printable
spellingShingle Yijiang Shi
Patrick Frost
Bao Hoang
Yonghui Yang
Carolyne Bardeleben
Joseph Gera
Alan Lichtenstein
MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
PLoS ONE
title MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
title_full MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
title_fullStr MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
title_full_unstemmed MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
title_short MNK1-induced eIF-4E phosphorylation in myeloma cells: a pathway mediating IL-6-induced expansion and expression of genes involved in metabolic and proteotoxic responses.
title_sort mnk1 induced eif 4e phosphorylation in myeloma cells a pathway mediating il 6 induced expansion and expression of genes involved in metabolic and proteotoxic responses
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0094011&type=printable
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