Interactions of the PDZ-protein MAGI-1 with adenovirus E4-ORF1 and high-risk papillomavirus E6 oncoproteins.
The oncoproteins of small DNA tumor viruses promote tumorigenesis by complexing with cellular factors intimately involved in the control of cell proliferation. The major oncogenic determinants for human adenovirus type 9 (Ad9) and high-risk human papillomaviruses (HPV) are the E4-ORF1 and E6 proteins, respectively. These seemingly unrelated viral oncoproteins are similar in that their transforming activities in cells depend, in part, on a carboxyl-terminal PDZ domain-binding motif which mediates interactions with the cellular PDZ-protein DLG. Here we demonstrated that both Ad9 E4-ORF1 and high-risk HPV E6 proteins also bind to the DLG-related PDZ-protein MAGI-1. These interactions resulted in MAGI-1 being aberrantly sequestered in the cytoplasm by the Ad9 E4-ORF1 protein or being targeted for degradation by high-risk HPV E6 proteins. Transformation-defective mutant viral proteins, however, were deficient for these activities. Our findings indicate that MAGI-1 is a member of a select group of cellular PDZ proteins targeted by both adenovirus E4-ORF1 and high-risk HPV E6 proteins and, in addition, suggest that the tumorigenic potentials of these viral oncoproteins depend, in part, on an ability to inhibit the function of MAGI-1 in cells.
Glaunsinger
B A
BA
Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.
Lee
S S
SS
Thomas
M
M
Banks
L
L
Javier
R
R
D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism; D017504:Adenovirus E4 Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins; D005455:Fluorescent Antibody Technique; D051528:Guanylate Kinases; D006207:Half-Life; D009154:Mutation / Q000235:genetics; D009703:Nucleoside-Phosphate Kinase / Q000737:chemistry* / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D015531:Radioimmunoprecipitation Assay; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014162:Transfection
D017504:Adenovirus E4 Proteins; D004268:DNA-Binding Proteins; C101120:E4 protein, Adenovirus 9; C068651:E6 protein, Human papillomavirus type 16; C052603:E6 protein, Human papillomavirus type 18; D009856:Oncogene Proteins, Viral; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases