title: p53 target DDA3 binds ASPP2 and inhibits its stimulation on p53-mediated BAX activation.
abstract: The p53 tumor suppressor functions in maintaining the integrity of the genome. We have previously reported that DDA3 is an oncoprotein transcriptionally regulated by p53. To explore mechanisms underlying DDA3 action, we searched for its interacting proteins by yeast two-hybrid screening, and identified ASPP2, a p53 binding protein, as its binding partner. The DDA3/ASPP2 binding was confirmed in vitro by GST pull-down and in vivo by immunofluorescence assay, which indicated colocalization of DDA3 and ASPP2. Interacting domain of DDA3 was mapped to amino acids 118-241, whereas both the N- and C-terminal regions of ASPP2 were capable of binding to DDA3. DDA3 dose-dependently inhibited ASPP2 in stimulating the p53-mediated BAX promoter activation without interfering the binding of ASPP2 to p53. Together these results identify ASPP2 as a bona fide DDA3 interacting protein, and suggest that the ASPP2/DDA3 interaction may inhibit ASPP2 in stimulating the apoptotic signaling of p53.
authors.affiliation: Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155, Sec., 2 Linong Street, Taipei 112, Taiwan.
authors.forename: Wei-Tzu
authors.initials: WT
authors.lastname: Sun
authors.forename: Pei-Chen
authors.initials: PC
authors.lastname: Hsieh
authors.forename: Ming-Lun
authors.initials: ML
authors.lastname: Chiang
authors.forename: Mei-Chih
authors.initials: MC
authors.lastname: Wang
authors.forename: Fung-Fang
authors.initials: FF
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D051028:bcl-2-Associated X Protein / Q000235:genetics*
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; C485740:PSRC1 protein, human; D010750:Phosphoproteins; C090468:TP53BP2 protein, human; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D008156:Luciferases