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Tupperwar N, Meleppattu S, Shrivastava R, Baron N, Gilad A, Wagner G, Léger-Abraham M, Shapira M. A newly identified Leishmania IF4E-interacting protein, Leish4E-IP2, modulates the activity of cap-binding protein paralogs. Nucleic Acids Res 2020; 48:4405-4417. [PMID: 32232353 PMCID: PMC7192595 DOI: 10.1093/nar/gkaa173] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/04/2020] [Accepted: 03/16/2020] [Indexed: 01/06/2023] Open
Abstract
Translation of most cellular mRNAs in eukaryotes proceeds through a cap-dependent pathway, whereby the cap-binding complex, eIF4F, anchors the preinitiation complex at the 5′ end of mRNAs and regulates translation initiation. The requirement of Leishmania to survive in changing environments can explain why they encode multiple eIF4E (LeishIF4Es) and eIF4G (LeishIF4Gs) paralogs, as each could be assigned a discrete role during their life cycle. Here we show that the expression and activity of different LeishIF4Es change during the growth of cultured promastigotes, urging a search for regulatory proteins. We describe a novel LeishIF4E-interacting protein, Leish4E-IP2, which contains a conserved Y(X)4LΦ IF4E-binding-motif. Despite its capacity to bind several LeishIF4Es, Leish4E-IP2 was not detected in m7GTP-eluted cap-binding complexes, suggesting that it could inhibit the cap-binding activity of LeishIF4Es. Using a functional assay, we show that a recombinant form of Leish4E-IP2 inhibits the cap-binding activity of LeishIF4E-1 and LeishIF4E-3. Furthermore, we show that transgenic parasites expressing a tagged version of Leish4E-IP2 also display reduced cap-binding activities of tested LeishIF4Es, and decreased global translation. Given its ability to bind more than a single LeishIF4E, we suggest that Leish4E-IP2 could serve as a broad-range repressor of Leishmania protein synthesis.
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Affiliation(s)
- Nitin Tupperwar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Shimi Meleppattu
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02138, USA
| | - Rohit Shrivastava
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Nofar Baron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ayelet Gilad
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02138, USA
| | - Mélissa Léger-Abraham
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Michal Shapira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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