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J Biol Chem. 2018 Nov 2;293(44):17240-17247. doi: 10.1074/jbc.RA118.003945. Epub 2018 Sep 13.

Discovery and characterization of conserved binding of eIF4E 1 (CBE1), a eukaryotic translation initiation factor 4E-binding plant protein.

Author information

1
From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712.
2
From the Department of Molecular Biosciences and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712 kbrowning@cm.utexas.edu.

Abstract

In many eukaryotes, translation initiation is regulated by proteins that bind to the mRNA cap-binding protein eukaryotic translation initiation factor 4E (eIF4E). These proteins commonly prevent association of eIF4E with eIF4G or form repressive messenger ribonucleoproteins that exclude the translation machinery. Such gene-regulatory mechanisms in plants, and even the presence of eIF4E-interacting proteins other than eIF4G (and the plant-specific isoform eIFiso4G, which binds eIFiso4E), are unknown. Here, we report the discovery of a plant-specific protein, conserved binding of eIF4E 1 (CBE1). We found that CBE1 has an evolutionarily conserved eIF4E-binding motif in its N-terminal domain and binds eIF4E or eIFiso4E in vitro CBE1 thereby forms cap-binding complexes and is an eIF4E-dependent constituent of these complexes in vivo Of note, plant mutants lacking CBE1 exhibited dysregulation of cell cycle-related transcripts and accumulated higher levels of mRNAs encoding proteins involved in mitosis than did WT plants. Our findings indicate that CBE1 is a plant protein that can form mRNA cap-binding complexes having the potential for regulating gene expression. Because mammalian translation factors are known regulators of cell cycle progression, we propose that CBE1 may represent such first translation factor-associated plant-specific cell cycle regulator.

KEYWORDS:

4E-binding protein; Arabidopsis thaliana; RNA cap–binding complex; cell cycle; eIF4E-binding; eukaryotic translation initiation factor 4E (eIF4E); mitosis; protein synthesis; translation; translation control; translation initiation factor

PMID:
30213859
PMCID:
PMC6222093
[Available on 2019-11-02]
DOI:
10.1074/jbc.RA118.003945
[Indexed for MEDLINE]

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