Analysis of molecular interactions of the p53-family p51(p63) gene products in a yeast two-hybrid system: homotypic and heterotypic interactions and association with p53-regulatory factors.
p51 in the p53 tumor suppressor family, also referred to as p63, encodes multiple isoforms including p51A (TAp63gamma) and p51B (TAp63alpha). The p53 protein forms a tetramer, and its stability and activity are regulated by molecular association with viral and cellular proteins and by biochemical modifications. Using a yeast two-hybrid system, the p51A and p51B isoforms were examined for homotypic and heterotypic interactions in the p53 family proteins and for their affinity to the p53-regulatory factors. Results indicate a homotypic interaction dependent on the presumed oligomerization domain of the p51 proteins. The possibility of a weak heterotypic interaction between p51 and p73 proteins was suggested, while association between p51 and p53 appeared improbable. Furthermore, unlike p53, the p51 proteins failed to display an affinity to SV40 large T antigen or MDM2-family proteins. Having several features in common with p53, the p51 proteins may function in biological processes apart from p53.
Department of Retroviral Regulation, Medical Research Division, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
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T
Kojima
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Ikawa
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Katoh
D000595:Amino Acid Sequence; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016147:Genes, Tumor Suppressor; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
D000952:Antigens, Polyomavirus Transforming; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; C115051:TP63 protein, human; C000606460:TP73 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2