The translational inhibitor 4E-BP is an effector of PI(3)K/Akt signalling and cell growth in Drosoph

Abstract

The initiation factor 4E for eukaryotic translation (eIF4E) binds the messenger RNA 5′-cap structure and is important in the regulation of protein synthesis1. Mammalian eIF4E activity is inhibited when the initiation factor binds to the translational repressors, the 4E-binding proteins (4E-BPS)1. Here we show that the Drosophila melanogaster 4E-BP (d4E-BP) is a downstream target of the phosphatidylinositol-3-OH kinase (PI(3)K) signal-transduction cascade, which affects the interaction of d4E-BP with eIF4E. Ectopic expression of a highly active d4E-BP mutant in wing-imaginal discs causes a reduction of wing size, brought about by a decrease in cell size and number. A marked reduction in cell size was also observed in post-mitotic cells. Expression of d4E-BP in the eye and wing together with PI(3)K or dAkt1, the serine/threonine kinase downstream of PI(3)K, resulted in suppression of the growth phenotype elicited by these kinases. Our results support a role for d4E-BP as an effector of cell growth.

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Miron, M., Verdú, J., Lachance, P. et al. The translational inhibitor 4E-BP is an effector of PI(3)K/Akt signalling and cell growth in Drosophila. Nat Cell Biol 3, 596–601 (2001). https://doi.org/10.1038/35078571

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