Characterization of eIF3k

A newly discovered subunit of mammalian translation initiation factor eIF3

Greg L. Mayeur, Christopher S. Fraser, Franck Peiretti, Karen L. Block, John W B Hershey

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Mammalian translation initiation factor 3 (eIF3) is a multisubunit complex containing at least 12 subunits with an apparent aggregate mass of ≈ 700 kDa. eIF3 binds to the 40S ribosomal subunit, promotes the binding of methionyl-tRNAi and mRNA, and interacts with several other initiation factors to form the 40S initiation complex. Human cDNAs encoding 11 of the 12 subunits have been isolated previously; here we report the cloning and characterization of a twelfth subunit, a 28-kDa protein named eIF3k. Evidence that eIF3k is present in the eIF3 complex was obtained. A monoclonal anti-eIF3a (p170) Ig coimmunoprecipitates eIF3k with the eIF3 complex. Affinity purification of histidine-tagged eIF3k from transiently transfected COS cells copurifies other eIF3 subunits. eIF3k colocalizes with eIF3 on 40S ribosomal subunits. eIF3k coexpressed with five other 'core' eIF3 subunits in baculovirus-infected insect cells, forms a stable, immunoprecipitatable, complex with the 'core'. eIF3k interacts directly with eIF3c, eIF3g and eIF3j by glutathione S-transferase pull-down assays. Sequences homologous with eIF3k are found in the genomes of Caenorhabitis elegans, Arabidopsis thaliana and Drosophila melanogaster, and a homologous protein has been reported to be present in wheat eIF3. Its ubiquitous expression in human tissues, yet its apparent absence in Saccharomyces cerevisiae and Schizosaccharomyces pombe, suggest a unique regulatory role for eIF3k in higher organisms. The studies of eIF3k complete the characterization of mammalian eIF3 subunits.

Original languageEnglish (US)
Pages (from-to)4133-4139
Number of pages7
JournalEuropean Journal of Biochemistry
Volume270
Issue number20
DOIs
StatePublished - Oct 2003

Fingerprint

Eukaryotic Small Ribosome Subunits
Peptide Initiation Factors
Prokaryotic Initiation Factor-3
Schizosaccharomyces
Baculoviridae
Cloning
COS Cells
Sequence Homology
Glutathione Transferase
Drosophila melanogaster
Arabidopsis
Histidine
Yeast
Triticum
Purification
Saccharomyces cerevisiae
Insects
Organism Cloning
Assays
Proteins

Keywords

  • eIF3
  • eIF3k
  • Initiation factor
  • Protein synthesis
  • Translation initiation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Characterization of eIF3k : A newly discovered subunit of mammalian translation initiation factor eIF3. / Mayeur, Greg L.; Fraser, Christopher S.; Peiretti, Franck; Block, Karen L.; Hershey, John W B.

In: European Journal of Biochemistry, Vol. 270, No. 20, 10.2003, p. 4133-4139.

Research output: Contribution to journalArticle

Mayeur, Greg L. ; Fraser, Christopher S. ; Peiretti, Franck ; Block, Karen L. ; Hershey, John W B. / Characterization of eIF3k : A newly discovered subunit of mammalian translation initiation factor eIF3. In: European Journal of Biochemistry. 2003 ; Vol. 270, No. 20. pp. 4133-4139.
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