Eukaryotic translation initiation factor 3, subunit a, regulates the extracellular signal-regulated kinase pathway

Tian-Rui Xu, Rui-Fang Lu, David Romano, Andrew Pitt, Miles D Houslay, Graeme Milligan, Walter Kolch

Research output: Contribution to journalArticlepeer-review


The extracellular signal-regulated kinase (ERK) pathway participates in the control of numerous cellular processes, including cell proliferation. Since its activation kinetics are critical for to its biological effects, they are tightly regulated. We report that the protein translation factor, eukaryotic translation initiation factor 3, subunit a (eIF3a), binds to SHC and Raf-1, two components of the ERK pathway. The interaction of eIF3a with Raf-1 is increased by ß-arrestin2 expression and transiently decreased by epidermal growth factor (EGF) stimulation in a concentration-dependent manner. The EGF-induced decrease in Raf-1-eIF3a association kinetically correlates with the time course of ERK activation. eIF3a interferes with Raf-1 activation and eIF3a downregulation by small interfering RNA enhances ERK activation, early gene expression, DNA synthesis, expression of neuronal differentiation markers in PC12 cells, and Ras-induced focus formation in NIH 3T3 cells. Thus, eIF3a is a negative modulator of ERK pathway activation and its biological effects.
Original languageEnglish
Pages (from-to)88-95
Number of pages8
JournalMolecular and Cellular Biology
Issue number1
Early online date1 Oct 2011
Publication statusPublished - Jan 2012


  • animals
  • arrestins
  • cell differentiation
  • epidermal growth factor
  • eukaryotic initiation factor-3
  • extracellular signal-regulated MAP kinases
  • gene knockdown techniques
  • HEK293 cells
  • humans
  • MAP kinase signaling system
  • mice
  • NIH 3T3 cCells
  • PC12 cells
  • protein binding
  • proto-oncogene proteins c-raf
  • rats


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