Journal Article

Distinct interactions of eIF4A and eIF4E with RNA helicase Ded1 stimulate translation in vivo

Lorsch, Jon R, Gupta, Neha, Hinnebusch, Alan G, Gulay, Suna

2020

Overview

Yeast DEAD-box helicase Ded1 stimulates translation initiation, particularly of mRNAs with structured 5'UTRs. Interactions of the Ded1 N-terminal domain (NTD) with eIF4A, and Ded1-CTD with eIF4G, subunits of eIF4F, enhance Ded1 unwinding activity and stimulation of preinitiation complex (PIC) assembly in vitro. However, the importance of these interactions, and of Ded1-eIF4E association, in vivo were poorly understood. We identified separate amino acid clusters in the Ded1-NTD required for binding to eIF4A or eIF4E in vitro. Disrupting each cluster selectively impairs native Ded1 association with eIF4A or eIF4E, and reduces cell growth, polysome assembly, and translation of reporter mRNAs with structured 5'UTRs. It also impairs Ded1 stimulation of PIC assembly on a structured mRNA in vitro. Ablating Ded1 interactions with eIF4A/eIF4E unveiled a requirement for the Ded1-CTD for robust initiation. Thus, Ded1 function in vivo is stimulated by independent interactions of its NTD with eIF4E and eIF4A, and its CTD with eIF4G.

• Publisher: eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: Amino acids / Binding sites / Cell growth / Chromosomes and Gene Expression / DEAD-box RNA Helicases - chemistry / DEAD-box RNA Helicases - genetics / DEAD-box RNA Helicases - metabolism / Ded1/Ddx3 / DNA helicase / eIF4A / eIF4E / eIF4G / Eukaryotic Initiation Factor-4E - chemistry / Eukaryotic Initiation Factor-4E - genetics / Eukaryotic Initiation Factor-4E - metabolism / Eukaryotic Initiation Factor-4F - chemistry / Eukaryotic Initiation Factor-4F - genetics / Eukaryotic Initiation Factor-4F - metabolism / Gene Expression Regulation, Fungal / Initiation factor eIF-4E / Initiation factor eIF-4G / Kinases / Mammals / mRNA / Mutation / Polyribosomes - genetics / Polyribosomes - metabolism / Protein Binding / Protein Biosynthesis / Protein Domains / Proteins / Recruitment / RNA helicase / RNA Helicases - chemistry / RNA Helicases - genetics / RNA Helicases - metabolism / Saccharomyces cerevisiae - chemistry / Saccharomyces cerevisiae - enzymology / Saccharomyces cerevisiae - genetics / Saccharomyces cerevisiae - growth & development / Saccharomyces cerevisiae Proteins - chemistry / Saccharomyces cerevisiae Proteins - genetics / Saccharomyces cerevisiae Proteins - metabolism / Translation initiation / Unwinding