Adenovirus type 5 E1A and E6 proteins of low-risk cutaneous beta-human papillomaviruses suppress cell transformation through interaction with FOXK1/K2 transcription factors

J Virol. 2010 Mar;84(6):2719-31. doi: 10.1128/JVI.02119-09. Epub 2010 Jan 6.


The adenovirus (Adv) oncoprotein E1A stimulates cell proliferation and inhibits differentiation. These activities are primarily linked to the N-terminal region (exon 1) of E1A, which interacts with multiple cellular protein complexes. The C terminus (exon 2) of E1A antagonizes these processes, mediated in part through interaction with C-terminal binding proteins 1 and 2 (CtBP1/2). To identify additional cellular E1A targets that are involved in the modulation of E1A C-terminus-mediated activities, we undertook tandem affinity purification of E1A-associated proteins. Through mass spectrometric analysis, we identified several known E1A-interacting proteins as well as novel E1A targets, such as the forkhead transcription factors, FOXK1/K2. We identified a Ser/Thr-containing sequence motif in E1A that mediated interaction with FOXK1/K2. We demonstrated that the E6 proteins of two beta-human papillomaviruses (HPV14 and HPV21) associated with epidermodysplasia verruciformis also interacted with FOXK1/K2 through a motif similar to that of E1A. The E1A mutants deficient in interaction with FOXK1/K2 induced enhanced cell proliferation and oncogenic transformation. The hypertransforming activity of the mutant E1A was suppressed by HPV21 E6. An E1A-E6 chimeric protein containing the Ser/Thr domain of the E6 protein in E1A interacted efficiently with FOXK1/K2 and inhibited cell transformation. Our results suggest that targeting FOXK1/K2 may be a common mechanism for certain beta-HPVs and Adv5. E1A exon 2 mutants deficient in interaction with the dual-specificity kinases DYRK1A/1B and their cofactor HAN11 also induced increased cell proliferation and transformation. Our results suggest that the E1A C-terminal region may suppress cell proliferation and oncogenic transformation through interaction with three different cellular protein complexes: FOXK1/K2, DYRK(1A/1B)/HAN11, and CtBP1/2.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Adenovirus E1A Proteins / genetics
  • Adenovirus E1A Proteins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Betapapillomavirus / genetics
  • Betapapillomavirus / physiology*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Proliferation
  • Cell Transformation, Neoplastic*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Forkhead Transcription Factors / genetics
  • Forkhead Transcription Factors / metabolism*
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Oncogene Proteins, Viral / genetics
  • Oncogene Proteins, Viral / metabolism*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Skin Neoplasms / pathology
  • Skin Neoplasms / virology


  • Adaptor Proteins, Signal Transducing
  • Adenovirus E1A Proteins
  • Carrier Proteins
  • DCAF7 protein, human
  • DNA-Binding Proteins
  • FOXK1 protein, human
  • Forkhead Transcription Factors
  • Nuclear Proteins
  • Oncogene Proteins, Viral
  • Recombinant Fusion Proteins
  • interleukin binding factor
  • Dyrk kinase
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases