Adenovirus type 5 E1A and E6 proteins of low-risk cutaneous beta-human papillomaviruses suppress cell transformation through interaction with FOXK1/K2 transcription factors.
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.
Komorek
Jessica
J
Institute for Molecular Virology, Saint Louis University School of Medicine, Doisy Research Center, 1100 South Grand Boulevard, Saint Louis, Missouri 63104, USA.
Kuppuswamy
Mohan
M
Subramanian
T
T
Vijayalingam
S
S
Lomonosova
Elena
E
Zhao
Ling-Jun
LJ
Mymryk
Joe S
JS
Schmitt
Kimberly
K
Chinnadurai
G
G
D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D052686:Betapapillomavirus / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012878:Skin Neoplasms / Q000473:pathology / Q000821:virology; D000097603:Dyrk Kinases
D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D000097603:Dyrk Kinases; C515143:DCAF7 protein, human; C495879:FOXK1 protein, human; C070635:interleukin binding factor