Chimaeric HPV E6 proteins allow dissection of the proteolytic pathways regulating different E6 cellular target proteins.
The ability of HPV E6 oncoproteins to induce the degradation of PDZ domain-containing MAGUK proteins correlates with their malignant potential. We previously showed that the HPV-6 E6 protein, when provided with the PDZ-binding domain from HPV-18 E6, acquires the ability to bind the Discs Large (Dlg) tumour suppressor and target it for degradation. Based on this finding we have extended this analysis to E6 proteins from a variety of different papillomavirus types. Cloning a PDZ-binding sequence onto the C-terminus of E6 proteins derived from low-risk mucosal, and low and high-risk cutaneous papillomavirus types, enables them to bind Dlg and a second MAGUK family member, MAGI-1. This renders the mucosally-derived low-risk chimaeric HPV E6 proteins capable of targeting Dlg for degradation, but they are unable to induce significant levels of degradation of MAGI-1. In contrast, none of the E6 proteins derived from cutaneous papillomavirus types induce significant degradation of either MAGI-1 or Dlg when provided with a PDZ-binding domain. These results demonstrate significant differences, both between mucosal and cutaneous HPV E6 proteins and in the pathways required for Dlg and MAGI-1 degradation.
Pim
David
D
International Centre for Genetic Engineering and Biotechnology, Area Science Park, Padriciano-99, I-34012, Trieste, Italy. pim@icgeb.org.it
Thomas
Miranda
M
Banks
Lawrence
L
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D016384:Consensus Sequence; D004268:DNA-Binding Proteins; D000074288:Discs Large Homolog 1 Protein; D005813:Genes, Synthetic; D051528:Guanylate Kinases; D006801:Humans; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009703:Nucleoside-Phosphate Kinase / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D027383:Papillomaviridae / Q000235:genetics / Q000472:pathogenicity; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D048868:Adaptor Proteins, Signal Transducing; C513314:DLG1 protein, human; D004268:DNA-Binding Proteins; D000074288:Discs Large Homolog 1 Protein; C469554:E6 protein, Cottontail rabbit papillomavirus; C469553:E6 protein, Human papillomavirus type 11; C052603:E6 protein, Human papillomavirus type 18; C118860:E6 protein, Human papillomavirus type 6; C466081:E6 protein, Human papillomavirus type 8; C466080:E6 protein, human papillomavirus type 1; D008565:Membrane Proteins; D009856:Oncogene Proteins, Viral; D011506:Proteins; D011993:Recombinant Fusion Proteins; C059269:protein E6, Bovine papillomavirus; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases