title: Insight into the structural basis of pro- and antiapoptotic p53 modulation by ASPP proteins.
abstract: p53-dependent apoptosis is modulated by the ASPP family of proteins (apoptosis-stimulating proteins of p53; also called ankyrin repeat-, Src homology 3 domain-, and Pro-rich region-containing proteins). Its three known members, ASPP1, ASPP2, and iASPP, were previously found to interact with p53, influencing the apoptotic response of cells without affecting p53-induced cell cycle arrest. More specifically, the bona fide tumor suppressors, ASPP1 and ASPP2, bind to the core domain of p53 and stimulate transcription of apoptotic genes, whereas oncogenic iASPP also binds to the p53 core domain but inhibits p53-dependent apoptosis. Although the general interaction regions are known, details of the interfaces for each p53-ASPP complex have not been evaluated. We undertook a comprehensive biophysical characterization of ASPP-p53 complex formation and mapped the binding interfaces by NMR. We found that the interaction interface on p53 for the proapoptotic protein ASPP2 is distinct from that for the antiapoptotic iASPP. ASPP2 primarily binds to the core domain of p53, whereas iASPP predominantly interacts with a linker region adjacent to the core domain. Our detailed structural analyses of the ASPP-p53 interactions provide insight into the structural basis of the differential behavior of pro- and antiapoptotic ASPP family members.
authors.affiliation: Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260.
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Ahn
authors.affiliation: Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260.
authors.forename: In-Ja L
authors.initials: IL
authors.lastname: Byeon
authors.affiliation: Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260.
authors.forename: Chang-Hyeock
authors.initials: CH
authors.lastname: Byeon
authors.affiliation: Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260. Electronic address: amg100@pitt.edu.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Gronenborn
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding / Q000502:physiology; D020836:Protein Structure, Quaternary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D012097:Repressor Proteins; D013329:Structure-Activity Relationship; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; C498406:PPP1R13B protein, human; C119612:PPP1R13L protein, human; D012097:Repressor Proteins; C495901:TP53 protein, human; C090468:TP53BP2 protein, human; D016159:Tumor Suppressor Protein p53