DrosophilaMe31B is a dual eIF4E-interacting protein

LAYANA, CARLA; SALVADOR VILARDO, EMILIANO; CORUJO, GONZALO; HERNÁNDEZ, GRECO; RIVERA-POMAR, ROLANDO

JOURNAL OF MOLECULAR BIOLOGY

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2023 vol. 435

0022-2836

Eukaryotic translation initiation factor 4E (eIF4E) is a key factor involved in different aspects ofmRNA metabolism. Drosophila melanogaster genome encodes eight eIF4E isoforms, and thecanonical isoform eIF4E-1 is a ubiquitous protein that plays a key role in mRNA translation. eIF4E-3 is specifically expressed in testis and controls translation during spermatogenesis. In eukaryoticcells, translational control and mRNA decay is highly regulated in different cytoplasmicribonucleoprotein foci, which include the processing bodies (PBs). In this study, we show thatDrosophila eIF4E-1 and eIF4E-3 occur in PBs along the DEAD-box RNA helicase Me31B. Weshow that Me31B interacts with eIF4E-1 and eIF4E-3 by means of yeast two-hybrid system, FRETin D. melanogaster S2 cells and coimmunoprecipitation in testis. Truncation and point mutationsof Me31B proteins show two eIF4E-binding sites located in different protein domains. ResiduesY401-L407 (at the carboxy-terminus) are essential for interaction with eIF4E-1, whereas residuesF63-L70 (at the amino-terminus) are critical for interaction with eIF4E-3. The residue W117 ineIF4E-1 and the homolog position F103 in eIF4E-3 are necessary for Me31B-eIF4E interactionsuggesting that the change of tryptophan to phenylalanine provides specificity. Me31B representsa novel type of eIF4E-interacting protein with dual and specific interaction domains that might berecognized by different eIF4E isoforms in different tissues, adding complexity to the control ofgene expression in eukaryotes.