Translation initiation factor 4E (eIF4E) is a cytoplasmic cap-binding protein that is required for cap-dependent translation initiation. Here, we have shown that eIF4E is ubiquitinated primarily at Lys-159 and incubation of cells with a proteasome inhibitor leads to increased eIF4E levels, suggesting the proteasome-dependent proteolysis of ubiquitinated eIF4E. Ubiquitinated eIF4E retained its cap binding ability, whereas eIF4E phosphorylation and eIF4G binding were reduced by ubiquitination. The W73A mutant of eIF4E exhibited enhanced ubiquitination/degradation, and 4E-BP overexpression protected eIF4E from ubiquitination/degradation. Because heat shock or the expression of the carboxyl terminus of heat shock cognate protein 70-interacting protein (Chip) dramatically increased eIF4E ubiquitination, Chip may be at least one ubiquitin E3 ligase responsible for eIF4E ubiquitination. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc.
CITATION STYLE
Murata, T., & Shimotohno, K. (2006). Ubiquitination and proteasome-dependent degradation of human eukaryotic translation initiation factor 4E. Journal of Biological Chemistry, 281(30), 20788–20800. https://doi.org/10.1074/jbc.M600563200
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