title: Effects of oncogenic mutations and DNA response elements on the binding of p53 to p53-binding protein 2 (53BP2).
abstract: The tumor suppressor p53 is frequently mutated in human cancers. Upon activation it can induce cell cycle arrest or apoptosis. ASPP2 can specifically stimulate the apoptotic function of p53 but not cell cycle arrest, but the mechanism of enhancing the activation of pro-apoptotic genes over cell cycle arrest genes remains unknown. In this study, we analyzed the binding of 53BP2 (p53-binding protein 2, the C-terminal domain of ASPP2) to p53 core domain and various mutants using biophysical techniques. We found that several p53 core domain mutations (R181E, G245S, R249S, R273H) have different effects on the binding of DNA response elements and 53BP2. Further, we investigated the existence of a ternary complex consisting of 53BP2, p53, and DNA response elements to gain insight into the specific pro-apoptotic activation of p53. We found that binding of 53BP2 and DNA to p53 is mutually exclusive in the case of GADD45, p21, Bax, and PIG3. Both pro-apoptotic and non-apoptotic response elements were competed off p53 by 53BP2 with no indication of a ternary complex.
authors.affiliation: Centre for Protein Engineering, Medical Research Council, Hills Road, Cambridge CB2 2QH, United Kingdom.
authors.forename: Henning
authors.initials: H
authors.lastname: Tidow
authors.forename: Dmitry B
authors.initials: DB
authors.lastname: Veprintsev
authors.forename: Stefan M V
authors.initials: SM
authors.lastname: Freund
authors.forename: Alan R
authors.initials: AR
authors.lastname: Fersht
mesh_terms: D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins; D019540:Area Under Curve; D001665:Binding Sites; D001667:Binding, Competitive; D002151:Calorimetry; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D019793:Fluorescein; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D006801:Humans; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020218:Response Elements / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014461:Ultracentrifugation; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D005456:Fluorescent Dyes; C090468:TP53BP2 protein, human; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D004247:DNA; D019793:Fluorescein