Functional reconstitution of human eukaryotic translation initiation factor 3 (eIF3)

Chaomin Sun, Aleksandar Todorovic, Jordi Querol-Audí, Yun Bai, Nancy Villa, Monica Snyder, John Ashchyan, Christopher S. Lewis, Abbey Hartland, Scott Gradia, Christopher S. Fraser, Jennifer A. Doudna, Eva Nogales, Jamie H D Cate

Research output: Contribution to journalArticlepeer-review

86 Scopus citations


Protein fate in higher eukaryotes is controlled by three complexes that share conserved architectural elements: the proteasome, COP9 signalosome, and eukaryotic translation initiation factor 3 (eIF3). Here we reconstitute the 13-subunit human eIF3 in Escherichia coli, revealing its structural core to be the eight subunits with conserved orthologues in the proteasome lid complex and COP9 signalosome. This structural core in eIF3 binds to the small (40S) ribosomal subunit, to translation initiation factors involved in mRNA cap-dependent initiation, and to the hepatitis C viral (HCV) internal ribosome entry site (IRES) RNA. Addition of the remaining eIF3 subunits enables reconstituted eIF3 to assemble intact initiation complexes with the HCV IRES. Negative-stain EM reconstructions of reconstituted eIF3 further reveal how the approximately 400 kDa molecular mass structural core organizes the highly flexible 800 kDa molecular mass eIF3 complex, and mediates translation initiation.

Original languageEnglish (US)
Pages (from-to)20473-20478
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number51
StatePublished - Dec 20 2011


  • Electron microscopy
  • Protein synthesis
  • Supramolecular complex assembly
  • Translation regulation

ASJC Scopus subject areas

  • General


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