Mutational analysis of the discs large tumour suppressor identifies domains responsible for human papillomavirus type 18 E6-mediated degradation.
The discs large (Dlg) tumour suppressor protein is targeted for ubiquitin-mediated degradation by the high-risk human papillomavirus E6 proteins. To understand further the mechanisms behind this, a mutational analysis of Dlg was undertaken. This study demonstrates that an intact PDZ domain 2 (PDZ2) on Dlg is necessary for the ability of E6 to bind and degrade Dlg. However, additional residues within the amino-terminal portion of Dlg are also required for optimal E6 activity. Stable cell lines expressing different Dlg mutants were also established and these confirm that Dlg is regulated intrinsically by the proteasome in the absence of E6; however, in this case, the sequences responsible for regulating Dlg stability lie predominantly within PDZ2. These results suggest that there are at least two mechanisms for regulating Dlg protein stability and that the pathways used by E6 are not necessarily the same as those used in the cell in its absence.
Gardiol
Daniela
D
Instituto de Biologia Molecular y Celular de Rosario (IBR-CONICET), Departamento de Microbiologia, Facultad de Ciencias Bioquimicas, Suipacha 531, 2000 Rosario, Argentina1.
Galizzi
Silvina
S
Instituto de Biologia Molecular y Celular de Rosario (IBR-CONICET), Departamento de Microbiologia, Facultad de Ciencias Bioquimicas, Suipacha 531, 2000 Rosario, Argentina1.
Banks
Lawrence
L
International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste, Italy2.
D048868:Adaptor Proteins, Signal Transducing; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins; D000074288:Discs Large Homolog 1 Protein; D016147:Genes, Tumor Suppressor; D006801:Humans; D008565:Membrane Proteins; D009097:Multienzyme Complexes / Q000378:metabolism; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D027383:Papillomaviridae / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C513314:DLG1 protein, human; D004268:DNA-Binding Proteins; D000074288:Discs Large Homolog 1 Protein; C052603:E6 protein, Human papillomavirus type 18; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D009856:Oncogene Proteins, Viral; D011506:Proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex