Ect2-Dependent rRNA Synthesis Is Required for KRAS-TRP53-Driven Lung Adenocarcinoma

Verline Justilien, Syed A. Ali, Lee Jamieson, Ning Yin, Adrienne D. Cox, Channing J. Der, Nicole R. Murray, Alan P. Fields

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


The guanine nucleotide exchange factor (GEF) epithelial cell transforming sequence 2 (Ect2) has been implicated in cancer. However, it is not clear how Ect2 causes transformation and whether Ect2 is necessary for tumorigenesis in vivo. Here, we demonstrate that nuclear Ect2 GEF activity is required for Kras-Trp53 lung tumorigenesis in vivo and that Ect2-mediated transformation requires Ect2-dependent rDNA transcription. Ect2 activates rRNA synthesis by binding the nucleolar transcription factor upstream binding factor 1 (UBF1) on rDNA promoters and recruiting Rac1 and its downstream effector nucleophosmin (NPM) to rDNA. Protein kinase Cι (PKCι)-mediated Ect2 phosphorylation stimulates Ect2-dependent rDNA transcription. Thus, Ect2 regulates rRNA synthesis through a PKCι-Ect2-Rac1-NPM signaling axis that is required for lung tumorigenesis.

Original languageEnglish (US)
Pages (from-to)256-269
Number of pages14
JournalCancer cell
Issue number2
StatePublished - Feb 13 2017


  • Ect2
  • nucleophosmin, NPM
  • protein kinase Cι, PKCι
  • rRNA synthesis
  • tumor initiation
  • upstream binding factor 1, UBF1

ASJC Scopus subject areas

  • Oncology
  • Cell Biology
  • Cancer Research


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