TY - JOUR
T1 - A novel 4E-interacting protein in Leishmania is involved in stage-specific translation pathways
AU - Zinoviev, Alexandra
AU - Léger, Mélissa
AU - Wagner, Gerhard
AU - Shapira, Michal
N1 - Funding Information:
US-Israel Binational Foundation (BSF, grant number 2007287 to M.S. and G.W.); Israel Science Foundation (ISF, grant No 395/09 to M.S.); National Institutes of Health (NIH, grant CA068262 to G.W.); Fonds de la Recherche en Santé au Québec (FRSQ) (to M.L.). Funding for open access charge: BSF, ISF, NIH.
PY - 2011/10/1
Y1 - 2011/10/1
N2 - In eukaryotes, exposure to stress conditions causes a shift from cap-dependent to cap-independent translation. In trypanosomatids, environmental switches are the driving force of a developmental program of gene expression, but it is yet unclear how their translation machinery copes with their constantly changing environment. Trypanosomatids have a unique cap structure (cap-4) and encode four highly diverged paralogs of the cap-binding protein, eIF4E; none were found to genetically complement a yeast mutant failing to express eIF4E. Here we show that in promastigotes, a typical cap-binding complex is anchored through LeishIF4E-4, which associates with components of the cap-binding pre-initiation complex. In axenic amastigotes, expression of LeishIF4E-4 decreases and the protein does not bind the cap, whereas LeishIF4E-1 maintains its expression level and associates with the cap structure and with translation initiation factors. However, LeishIF4E-1 does not interact with eIF4G-like proteins in both life stages, excluding its involvement in cap-dependent translation. Using pull-down assays and mass-spectrometry, we identified a novel, non-conserved 4E-Interacting Protein (Leish4E-IP), which binds to LeishIF4E-1 in promastigotes, but not in amastigotes. Yeast two-hybrid and NMR spectroscopy confirmed the specificity of this interaction. We propose that Leish4E-IP is a translation regulator that is involved in switching between cap-dependent and alternative translation pathways.
AB - In eukaryotes, exposure to stress conditions causes a shift from cap-dependent to cap-independent translation. In trypanosomatids, environmental switches are the driving force of a developmental program of gene expression, but it is yet unclear how their translation machinery copes with their constantly changing environment. Trypanosomatids have a unique cap structure (cap-4) and encode four highly diverged paralogs of the cap-binding protein, eIF4E; none were found to genetically complement a yeast mutant failing to express eIF4E. Here we show that in promastigotes, a typical cap-binding complex is anchored through LeishIF4E-4, which associates with components of the cap-binding pre-initiation complex. In axenic amastigotes, expression of LeishIF4E-4 decreases and the protein does not bind the cap, whereas LeishIF4E-1 maintains its expression level and associates with the cap structure and with translation initiation factors. However, LeishIF4E-1 does not interact with eIF4G-like proteins in both life stages, excluding its involvement in cap-dependent translation. Using pull-down assays and mass-spectrometry, we identified a novel, non-conserved 4E-Interacting Protein (Leish4E-IP), which binds to LeishIF4E-1 in promastigotes, but not in amastigotes. Yeast two-hybrid and NMR spectroscopy confirmed the specificity of this interaction. We propose that Leish4E-IP is a translation regulator that is involved in switching between cap-dependent and alternative translation pathways.
UR - http://www.scopus.com/inward/record.url?scp=80455178807&partnerID=8YFLogxK
U2 - 10.1093/nar/gkr555
DO - 10.1093/nar/gkr555
M3 - Article
AN - SCOPUS:80455178807
SN - 0305-1048
VL - 39
SP - 8404
EP - 8415
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 19
ER -