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EIF4F-LIKE COMPLEXES FORMED BY CAP-BINDING HOMOLOG TBEIF4E5 WITH TBEIF4G1 OR TBEIF4G2 ARE IMPLICATED IN POST-TRANSCRIPTIONAL REGULATION IN TRYPANOSOMA BRUCEI
Freire, Eden R. et al. | Date Issued: 2014
Author
Freire, Eden R.
Vashisht, Ajay A.
Malvezzi, Amaranta M.
Zuberek, Joanna
Langousis, Gerasimos
Saada, Edwin A.
Nascimento, Janaína de F.
Stepinski, Janusz
Darzynkiewicz, Edward
Hill, Kent
Melo Neto, Osvaldo P. de
Wohlschlegel, James A.
Sturm, Nancy R.
Campbell, David A.
Affilliation
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
University of California at Los Angeles. David Geffen School of Medicine. Department of Biological Chemistry. Los Angeles, California, USA.
University of California at Los Angeles. David Geffen School of Medicine. Department of Microbiology. Immunology and Molecular Genetics. Los Angeles, California, USA / Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.
University of Warsaw. Faculty of Physics. Institute of Experimental Physics. Division of Biophysics. Warsaw, Poland.
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.
University of Warsaw. Faculty of Physics. Institute of Experimental Physics. Division of Biophysics. Warsaw, Poland.
University of Warsaw. Faculty of Physics. Institute of Experimental Physics. Division of Biophysics. Warsaw, Poland / University of Warsaw. Centre of New Technologies. Warsaw, Poland.
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.
University of California at Los Angeles. David Geffen School of Medicine. Department of Biological Chemistry. Los Angeles, California, USA.
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
University of California at Los Angeles. David Geffen School of Medicine. Immunology and Molecular Genetics. Department of Microbiology. Los Angeles, California, USA.
Abstract
Members of the eIF4E mRNA cap-binding family are involved in translation and the modulation of transcript availability in other systems as part of a three-component complex including eIF4G and eIF4A. The kinetoplastids possess four described eIF4E and five eIF4G homologs. We have identified two new eIF4E family proteins in Trypanosoma brucei, and define distinct complexes associated with the fifth member, TbEIF4E5. The cytosolic TbEIF4E5 protein binds cap 0 in vitro. TbEIF4E5 was found in association with two of the five TbEIF4Gs. TbIF4EG1 bound TbEIF4E5, a 47.5-kDa protein with two RNA-binding domains, and either the regulatory protein 14-3-3 II or a 117.5-kDa protein with guanylyltransferase and methyltransferase domains in a potentially dynamic interaction. The TbEIF4G2/TbEIF4E5 complex was associated with a 17.9-kDa hypothetical protein and both 14-3-3 variants I and II. Knockdown of TbEIF4E5 resulted in the loss of productive cell movement, as evidenced by the inability of the cells to remain in suspension in liquid culture and the loss of social motility on semisolid plating medium, as well as a minor reduction of translation. Cells appeared lethargic, as opposed to compromised in flagellar function per se. The minimal use of transcriptional control in kinetoplastids requires these organisms to implement downstream mechanisms to regulate gene expression, and the TbEIF4E5/TbEIF4G1/117.5-kDa complex in particular may be a key player in that process. We suggest that a pathway involved in cell motility is affected, directly or indirectly, by one of the TbEIF4E5 complexes.
Keywords in Portuguese
Proteína
Cinetoplasto
PAC mRNA
Motilidade social
Fator de iniciação da tradução
 
Keywords
Kinetoplastid
Social motility
Translation initiation factor
 
DeCS
Fator de Iniciação 4E em Eucariotos
Metabolismo
Proteínas de Ligação ao Cap de RNA
Processamento Pós-Transcricional do RNA
Sequência de aminoácidos
Capuzes de RNA
Técnicas de Inativação de Genes
Humanos
Dados de Sequência Molecular
Ligação Proteica
RNA de Protozoário
 
Citation
FREIRE, Eden R. et al. eIF4F-like complexes formed by cap-binding homolog TbEIF4E5 with TbEIF4G1 or TbEIF4G2 are implicated in post-transcriptional regulation in Trypanosoma brucei. RNA, v. 20, n. 8, p. 1272–1286, Aug. 2014.
DOI
10.1261/rna.045534.114
ISSN
1469-9001