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Mukherjee S, Saha G, Roy NS, Naiya G, Ghosh MK, Roy S. A small HDM2 antagonist peptide and a USP7 inhibitor synergistically inhibit the p53-HDM2-USP7 circuit. Chem Biol Drug Des 2023; 102:126-136. [PMID: 37105726 DOI: 10.1111/cbdd.14255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 02/28/2023] [Accepted: 04/05/2023] [Indexed: 04/29/2023]
Abstract
HDM2, an E3 ubiquitin ligase, is a crucial regulator of many proliferation-related pathways. It is also one of the primary regulators of p53. USP7, a deubiquitinase, also plays a key role in the regulation of both p53 and HDM2, thus forming a small regulatory network with them. This network has emerged as an important drug target. Development of a synergistic combination targeting both proteins is desirable and important for regulating this module. We have developed a small helically constrained peptide that potently inhibited p53-HDM2 interaction and exerted anti-proliferative effects on p53+/+ cells. A combination of this peptide-when attached to cell entry and nuclear localization tags-and a USP7 inhibitor showed synergistic anti-proliferative effects against cells harboring wild-type alleles of p53. Synergistic inhibition of two important drug targets may lead to novel therapeutic strategies.
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Affiliation(s)
| | - Gouranga Saha
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata, India
| | | | - Gitashri Naiya
- Department of Biophysics, Bose Institute, Kolkata, India
| | - Mrinal K Ghosh
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), Kolkata, India
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute, Kolkata, India
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2
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Grinkevich VV, Vema A, Fawkner K, Issaeva N, Andreotti V, Dickinson ER, Hedström E, Spinnler C, Inga A, Larsson LG, Karlén A, Wilhelm M, Barran PE, Okorokov AL, Selivanova G, Zawacka-Pankau JE. Novel Allosteric Mechanism of Dual p53/MDM2 and p53/MDM4 Inhibition by a Small Molecule. Front Mol Biosci 2022; 9:823195. [PMID: 35720128 PMCID: PMC9198586 DOI: 10.3389/fmolb.2022.823195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/26/2022] [Indexed: 01/26/2023] Open
Abstract
Restoration of the p53 tumor suppressor for personalised cancer therapy is a promising treatment strategy. However, several high-affinity MDM2 inhibitors have shown substantial side effects in clinical trials. Thus, elucidation of the molecular mechanisms of action of p53 reactivating molecules with alternative functional principle is of the utmost importance. Here, we report a discovery of a novel allosteric mechanism of p53 reactivation through targeting the p53 N-terminus which promotes inhibition of both p53/MDM2 (murine double minute 2) and p53/MDM4 interactions. Using biochemical assays and molecular docking, we identified the binding site of two p53 reactivating molecules, RITA (reactivation of p53 and induction of tumor cell apoptosis) and protoporphyrin IX (PpIX). Ion mobility-mass spectrometry revealed that the binding of RITA to serine 33 and serine 37 is responsible for inducing the allosteric shift in p53, which shields the MDM2 binding residues of p53 and prevents its interactions with MDM2 and MDM4. Our results point to an alternative mechanism of blocking p53 interaction with MDM2 and MDM4 and may pave the way for the development of novel allosteric inhibitors of p53/MDM2 and p53/MDM4 interactions.
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Affiliation(s)
- Vera V. Grinkevich
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Aparna Vema
- Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Karin Fawkner
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Natalia Issaeva
- Department of Otolaryngology/Head and Neck Surgery, UNC-Chapel Hill, Chapel Hill, NC, United States
| | - Virginia Andreotti
- IRCCS Ospedale Policlinico San Martino, Genetics of Rare Cancers, Genoa, Italy
| | - Eleanor R. Dickinson
- Manchester Institute of Biotechnology, The School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Elisabeth Hedström
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Clemens Spinnler
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Alberto Inga
- Department CIBIO, University of Trento, Trento, Italy
| | - Lars-Gunnar Larsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Anders Karlén
- Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Margareta Wilhelm
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Perdita E. Barran
- Manchester Institute of Biotechnology, The School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Andrei L. Okorokov
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Galina Selivanova
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden,*Correspondence: Galina Selivanova, ; Joanna E. Zawacka-Pankau,
| | - Joanna E. Zawacka-Pankau
- Department of Medicine, Huddinge, Center for Hematology and Regenerative Medicine, Karolinska Institute, Stockholm, Sweden,*Correspondence: Galina Selivanova, ; Joanna E. Zawacka-Pankau,
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3
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Deciphering the acetylation code of p53 in transcription regulation and tumor suppression. Oncogene 2022; 41:3039-3050. [PMID: 35487975 PMCID: PMC9149126 DOI: 10.1038/s41388-022-02331-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/14/2022] [Accepted: 04/20/2022] [Indexed: 12/16/2022]
Abstract
Although it is well established that p53-mediated tumor suppression mainly acts through its ability in transcriptional regulation, the molecular mechanisms of this regulation are not completely understood. Among a number of regulatory modes, acetylation of p53 attracts great interests. p53 was one of the first non-histone proteins found to be functionally regulated by acetylation and deacetylation, and subsequent work has established that reversible acetylation is a general mechanism for regulation of non-histone proteins. Unlike other types of post-translational modifications occurred during stress responses, the role of p53 acetylation has been recently validated in vivo by using the knockin mice with both acetylation-defective and acetylation-mimicking p53 mutants. Here, we review the role of acetylation in p53-mediated activities, with a focus on which specific acetylation sites are critical for p53-dependent transcription regulation during tumor suppression and how acetylation of p53 recruits specific “readers” to execute its promoter-specific regulation of different targets. We also discuss the role of p53 acetylation in differentially regulating its classic activities in cell cycle arrest, senescence and apoptosis as well as newly identified unconventional functions such as cell metabolism and ferroptosis.
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Marques MA, de Andrade GC, Silva JL, de Oliveira GAP. Protein of a thousand faces: The tumor-suppressive and oncogenic responses of p53. Front Mol Biosci 2022; 9:944955. [PMID: 36090037 PMCID: PMC9452956 DOI: 10.3389/fmolb.2022.944955] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/18/2022] [Indexed: 12/30/2022] Open
Abstract
The p53 protein is a pleiotropic regulator working as a tumor suppressor and as an oncogene. Depending on the cellular insult and the mutational status, p53 may trigger opposing activities such as cell death or survival, senescence and cell cycle arrest or proliferative signals, antioxidant or prooxidant activation, glycolysis, or oxidative phosphorylation, among others. By augmenting or repressing specific target genes or directly interacting with cellular partners, p53 accomplishes a particular set of activities. The mechanism in which p53 is activated depends on increased stability through post-translational modifications (PTMs) and the formation of higher-order structures (HOS). The intricate cell death and metabolic p53 response are reviewed in light of gaining stability via PTM and HOS formation in health and disease.
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Affiliation(s)
- Mayra A. Marques
- *Correspondence: Mayra A. Marques, ; Guilherme A. P. de Oliveira,
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Seera S, Nagarajaram HA. Effect of Disease Causing Missense Mutations on Intrinsically Disordered Regions in Proteins. Protein Pept Lett 2021; 29:254-267. [PMID: 34825861 DOI: 10.2174/0929866528666211126161200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/01/2021] [Accepted: 10/01/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND It is well known that disease-causing missense mutations (DCMMs) reduce the structural stability/integrity of the proteins with well-defined 3D structures, thereby impacting their molecular functions. However, it is not known in what way DCMMs affect the intrinsically disordered proteins (IDPs) that do not adopt well defined stable 3D structures. METHODS In order to investigate how DCMMs may impact intrinsically disordered regions (IDRs) in proteins, we undertook Molecular Dynamics (MD) based studies on three different examples of functionally important IDRs with known DCMMs. Our studies revealed that the functional impact of DCMMs is in reducing the conformational heterogeneity of IDRs, which is intrinsic and quintessential for their multi-faceted cellular roles. RESULTS These results are reinforced by energy landscapes of the wildtype and mutant IDRs where the former is characterized by many local minima separated by low barriers, whereas the latter are characterized by one global minimum and several local minima separated by high energy barriers. Our MD based studies also indicate that DCMMs stabilize very few structural possibilities of IDRs either by the newly formed interactions induced by the substituted side chains or by means of restricted or increased flexibilities of the backbone conformations at the mutation sites. CONCLUSION Furthermore, the structural possibilities stabilized by DCMMs do not support the native functional roles of the IDRs, thereby leading to disease conditions.
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Affiliation(s)
| | - Hampapathalu A Nagarajaram
- Laboratory of Computational Biology, Department of Systems and Computational Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
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7
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Liu Y, Tavana O, Gu W. p53 modifications: exquisite decorations of the powerful guardian. J Mol Cell Biol 2019; 11:564-577. [PMID: 31282934 PMCID: PMC6736412 DOI: 10.1093/jmcb/mjz060] [Citation(s) in RCA: 247] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/23/2019] [Accepted: 06/03/2019] [Indexed: 02/05/2023] Open
Abstract
The last 40 years have witnessed how p53 rose from a viral binding protein to a central factor in both stress responses and tumor suppression. The exquisite regulation of p53 functions is of vital importance for cell fate decisions. Among the multiple layers of mechanisms controlling p53 function, posttranslational modifications (PTMs) represent an efficient and precise way. Major p53 PTMs include phosphorylation, ubiquitination, acetylation, and methylation. Meanwhile, other PTMs like sumoylation, neddylation, O-GlcNAcylation, adenosine diphosphate (ADP)-ribosylation, hydroxylation, and β-hydroxybutyrylation are also shown to play various roles in p53 regulation. By independent action or interaction, PTMs affect p53 stability, conformation, localization, and binding partners. Deregulation of the PTM-related pathway is among the major causes of p53-associated developmental disorders or diseases, especially in cancers. This review focuses on the roles of different p53 modification types and shows how these modifications are orchestrated to produce various outcomes by modulating p53 activities or targeted to treat different diseases caused by p53 dysregulation.
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Affiliation(s)
- Yanqing Liu
- Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Omid Tavana
- Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wei Gu
- Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Roy S, Ghosh P, Ahmed I, Chakraborty M, Naiya G, Ghosh B. Constrained α-Helical Peptides as Inhibitors of Protein-Protein and Protein-DNA Interactions. Biomedicines 2018; 6:E118. [PMID: 30567318 PMCID: PMC6315407 DOI: 10.3390/biomedicines6040118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 02/06/2023] Open
Abstract
Intracellular regulatory pathways are replete with protein-protein and protein-DNA interactions, offering attractive targets for therapeutic interventions. So far, most drugs are targeted toward enzymes and extracellular receptors. Protein-protein and protein-DNA interactions have long been considered as "undruggable". Protein-DNA interactions, in particular, present a difficult challenge due to the repetitive nature of the B-DNA. Recent studies have provided several breakthroughs; however, a design methodology for these classes of inhibitors is still at its infancy. A dominant motif of these macromolecular interactions is an α-helix, raising possibilities that an appropriate conformationally-constrained α-helical peptide may specifically disrupt these interactions. Several methods for conformationally constraining peptides to the α-helical conformation have been developed, including stapling, covalent surrogates of hydrogen bonds and incorporation of unnatural amino acids that restrict the conformational space of the peptide. We will discuss these methods and several case studies where constrained α-helices have been used as building blocks for appropriate molecules. Unlike small molecules, the delivery of these short peptides to their targets is not straightforward as they may possess unfavorable cell penetration and ADME properties. Several methods have been developed in recent times to overcome some of these problems. We will discuss these issues and the prospects of this class of molecules as drugs.
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Affiliation(s)
- Siddhartha Roy
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
| | - Piya Ghosh
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
| | - Israr Ahmed
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
| | - Madhumita Chakraborty
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
| | - Gitashri Naiya
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
| | - Basusree Ghosh
- Department of Biophysics, Bose Institute, P1/12 CIT Scheme VII M, Kolkata 700054, India.
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9
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Banerjee S, Rakshit T, Sett S, Mukhopadhyay R. Interactions of Histone Acetyltransferase p300 with the Nuclear Proteins Histone and HMGB1, As Revealed by Single Molecule Atomic Force Spectroscopy. J Phys Chem B 2015; 119:13278-87. [PMID: 26419288 DOI: 10.1021/acs.jpcb.5b07795] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
One of the important properties of the transcriptional coactivator p300 is histone acetyltransferase (HAT) activity that enables p300 to influence chromatin action via histone modulation. p300 can exert its HAT action upon the other nuclear proteins too--one notable example being the transcription-factor-like protein HMGB1, which functions also as a cytokine, and whose accumulation in the cytoplasm, as a response to tissue damage, is triggered by its acetylation. Hitherto, no information on the structure and stability of the complexes between full-length p300 (p300FL) (300 kDa) and the histone/HMGB1 proteins are available, probably due to the presence of unstructured regions within p300FL that makes it difficult to be crystallized. Herein, we have adopted the high-resolution atomic force microscopy (AFM) approach, which allows molecularly resolved three-dimensional contour mapping of a protein molecule of any size and structure. From the off-rate and activation barrier values, obtained using single molecule dynamic force spectroscopy, the biochemical proposition of preferential binding of p300FL to histone H3, compared to the octameric histone, can be validated. Importantly, from the energy landscape of the dissociation events, a model for the p300-histone and the p300-HMGB1 dynamic complexes that HAT forms, can be proposed. The lower unbinding forces of the complexes observed in acetylating conditions, compared to those observed in non-acetylating conditions, indicate that upon acetylation, p300 tends to weakly associate, probably as an outcome of charge alterations on the histone/HMGB1 surface and/or acetylation-induced conformational changes. To our knowledge, for the first time, a single molecule level treatment of the interactions of HAT, where the full-length protein is considered, is being reported.
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Affiliation(s)
- S Banerjee
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
| | - T Rakshit
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
| | - S Sett
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
| | - R Mukhopadhyay
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
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10
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Liu W, Landgraf R. Phosphorylated and unphosphorylated serine 13 of CDC37 stabilize distinct interactions between its client and HSP90 binding domains. Biochemistry 2015; 54:1493-504. [PMID: 25619116 DOI: 10.1021/bi501129g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Folding and maturation of most protein kinases require chaperone assistance. In higher eukaryotes, CDC37 is the predominant cochaperone that facilitates the transfer of kinase clients to HSP90. Kinase recognition is thought to occur through the N-terminal domain, which has, thus far, eluded structure determination. Client processing also requires the phosphorylation of the N-terminal tail at Ser13 by protein kinase CK2 (casein kinase 2). How phosphorylation alters the molecular properties of CDC37 is not understood. We show that the phosphorylation at Ser13 induces a large shift toward a more compact structure, based on ANS fluorescence, while modestly increasing secondary structure. Moreover, this transition requires interactions of the N-terminal domain and the remainder of CDC37. The stabilizing property of the phosphorylation event can be recreated in trans by a (phospho-Ser13) peptide derived from the N-terminal tail. However, the phosphorylation-induced transition is not dependent on the transferred phosphate group but rather the loss of serine-like properties at position 13. The complete absence of the N-terminal tail results in reduced secondary structure and unresponsiveness to subsequent addition of peptides. The N-terminal tail may therefore serve as an intramolecular chaperone that ensures that CDC37 assumes one of two readily interconvertible states in a manner that impacts the interaction of the client binding N-domain and the MC-domains, involved in dimerization and HSP90 binding.
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Affiliation(s)
- Wenjun Liu
- Department of Biochemistry and Molecular Biology and ‡Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine , Miami, Florida 33136, United States
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11
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Saha T, Kar RK, Sa G. Structural and sequential context of p53: A review of experimental and theoretical evidence. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 117:250-263. [PMID: 25550083 DOI: 10.1016/j.pbiomolbio.2014.12.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/14/2014] [Accepted: 12/16/2014] [Indexed: 12/18/2022]
Abstract
Approximately 27 million people are suffering from cancer that contains either an inactivating missense mutation of TP53 gene or partially abrogated p53 signaling pathway. Concerted action of folded and intrinsically disordered domains accounts for multi-faceted role of p53. The intricacy of dynamic p53 structure is believed to shed light on its cellular activity for developing new cancer therapies. In this review, insights into structural details of p53, diverse single point mutations affecting its core domain, thermodynamic understanding and therapeutic strategies for pharmacological rescue of p53 function has been illustrated. An effort has been made here to bridge the structural and sequential evidence of p53 from experimental to computational studies. First, we focused on the individual domains and the crucial protein-protein or DNA-protein contacts that determine conformation and dynamic behavior of p53. Next, the oncogenic mutations associated with cancer and its contribution to thermodynamic fluctuation has been discussed. Thus the emerging anti-cancer strategies include targeting of destabilized cancer mutants with selective inhibition of its negative regulators. Recent advances in development of small molecule inhibitors and peptides exploiting p53-MDM2 interaction has been included. In a nutshell, this review attempts to describe structural biology of p53 which provide new openings for structure-guided rescue.
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Affiliation(s)
- Taniya Saha
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India
| | - Rajiv K Kar
- Division of Biophysics, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India
| | - Gaurisankar Sa
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India.
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12
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Reed SM, Quelle DE. p53 Acetylation: Regulation and Consequences. Cancers (Basel) 2014; 7:30-69. [PMID: 25545885 PMCID: PMC4381250 DOI: 10.3390/cancers7010030] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 12/12/2014] [Indexed: 12/11/2022] Open
Abstract
Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity, selection of growth inhibitory vs. apoptotic gene targets, and biological outcomes in response to diverse cellular insults. Yet recent in vivo evidence from mouse models questions the importance of p53 acetylation (at least at certain sites) as well as canonical p53 functions (cell cycle arrest, senescence and apoptosis) to tumor suppression. This review discusses the cumulative findings regarding p53 acetylation, with a focus on the acetyltransferases that modify p53 and the mechanisms regulating their activity. We also evaluate what is known regarding the influence of other post-translational modifications of p53 on its acetylation, and conclude with the current outlook on how p53 acetylation affects tumor suppression. Due to redundancies in p53 control and growing understanding that individual modifications largely fine-tune p53 activity rather than switch it on or off, many questions still remain about the physiological importance of p53 acetylation to its role in preventing cancer.
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Affiliation(s)
- Sara M Reed
- Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
| | - Dawn E Quelle
- Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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13
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Tinoco LW, Fraga JL, Anobom CD, Zolessi FR, Obal G, Toledo A, Pritsch O, Arruti C. Structural characterization of a neuroblast-specific phosphorylated region of MARCKS. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:837-49. [PMID: 24590112 DOI: 10.1016/j.bbapap.2014.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 02/07/2014] [Accepted: 02/20/2014] [Indexed: 11/19/2022]
Abstract
MARCKS (Myristoylated Alanine-Rich C Kinase substrate) is a natively unfolded protein that interacts with actin, Ca(2+)-Calmodulin, and some plasma membrane lipids. Such interactions occur at a highly conserved region that is specifically phosphorylated by PKC: the Effector Domain. There are two other conserved domains, MH1 (including a myristoylation site) and MH2, also located in the amino terminal region and whose structure and putative protein binding capabilities are currently unknown. MH2 sequence contains a serine that we described as being phosphorylated only in differentiating neurons (S25 in chick). Here, Circular Dichroism (CD) and Nuclear Magnetic Resonance (NMR) spectroscopy were used to characterize the phosphorylated and unphosphorylated forms of a peptide with the MARCKS sequence surrounding S25. The peptide phosphorylated at this residue is recognized by monoclonal antibody 3C3 (mAb 3C3). CD and NMR data indicated that S25 phosphorylation does not cause extensive modifications in the peptide structure. However, the sharper lines, the absence of multiple spin systems and relaxation dispersion data observed for the phosphorylated peptide suggested a more ordered structure. Surface Plasmon Resonance was employed to compare the binding properties of mAb 3C3 to MARCKS protein and peptide. SPR showed that mAb 3C3 binds to the whole protein and the peptide with a similar affinity, albeit different kinetics. The slightly ordered structure of the phosphorylated peptide might be at the origin of its ability to interact with mAb 3C3 antibody, but this binding did not noticeably modify the peptide structure.
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Affiliation(s)
- Luzineide W Tinoco
- Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco H, Rio de Janeiro 21941-902, RJ, Brazil.
| | - Jully L Fraga
- Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco H, Rio de Janeiro 21941-902, RJ, Brazil.
| | - Cristiane D Anobom
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT, Bloco A, Rio de Janeiro 21941-909, RJ, Brazil.
| | - Flavio R Zolessi
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
| | - Gonzalo Obal
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay.
| | - Andrea Toledo
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
| | - Otto Pritsch
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay.
| | - Cristina Arruti
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
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14
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Theillet FX, Smet-Nocca C, Liokatis S, Thongwichian R, Kosten J, Yoon MK, Kriwacki RW, Landrieu I, Lippens G, Selenko P. Cell signaling, post-translational protein modifications and NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2012; 54:217-36. [PMID: 23011410 PMCID: PMC4939263 DOI: 10.1007/s10858-012-9674-x] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/07/2012] [Indexed: 05/13/2023]
Abstract
Post-translationally modified proteins make up the majority of the proteome and establish, to a large part, the impressive level of functional diversity in higher, multi-cellular organisms. Most eukaryotic post-translational protein modifications (PTMs) denote reversible, covalent additions of small chemical entities such as phosphate-, acyl-, alkyl- and glycosyl-groups onto selected subsets of modifiable amino acids. In turn, these modifications induce highly specific changes in the chemical environments of individual protein residues, which are readily detected by high-resolution NMR spectroscopy. In the following, we provide a concise compendium of NMR characteristics of the main types of eukaryotic PTMs: serine, threonine, tyrosine and histidine phosphorylation, lysine acetylation, lysine and arginine methylation, and serine, threonine O-glycosylation. We further delineate the previously uncharacterized NMR properties of lysine propionylation, butyrylation, succinylation, malonylation and crotonylation, which, altogether, define an initial reference frame for comprehensive PTM studies by high-resolution NMR spectroscopy.
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Affiliation(s)
- Francois-Xavier Theillet
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Caroline Smet-Nocca
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Stamatios Liokatis
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Rossukon Thongwichian
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Jonas Kosten
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Mi-Kyung Yoon
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Richard W. Kriwacki
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Isabelle Landrieu
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Guy Lippens
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Philipp Selenko
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
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15
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Lum JK, Neuweiler H, Fersht AR. Long-range modulation of chain motions within the intrinsically disordered transactivation domain of tumor suppressor p53. J Am Chem Soc 2012; 134:1617-22. [PMID: 22176582 PMCID: PMC3265989 DOI: 10.1021/ja2078619] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The tumor suppressor p53 is a hub protein with a multitude of binding partners, many of which target its intrinsically disordered N-terminal domain, p53-TAD. Partners, such as the N-terminal domain of MDM2, induce formation of local structure and leave the remainder of the domain apparently disordered. We investigated segmental chain motions in p53-TAD using fluorescence quenching of an extrinsic label by tryptophan in combination with fluorescence correlation spectroscopy (PET-FCS). We studied the loop closure kinetics of four consecutive segments within p53-TAD and their response to protein binding and phosphorylation. The kinetics was multiexponential, showing that the conformational ensemble of the domain deviates from random coil, in agreement with previous findings from NMR spectroscopy. Phosphorylations or binding of MDM2 changed the pattern of intrachain kinetics. Unexpectedly, we found that upon binding and phosphorylation chain motions were altered not only within the targeted segments but also in remote regions. Long-range interactions can be induced in an intrinsically disordered domain by partner proteins that induce apparently only local structure or by post-translational modification.
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Affiliation(s)
- Jenifer K Lum
- Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
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16
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Does azurin bind to the transactivation domain of p53? A Trp phosphorescence study. Biophys Chem 2011; 159:287-93. [DOI: 10.1016/j.bpc.2011.07.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 11/19/2022]
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17
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Calabrese V, Mallette FA, Deschênes-Simard X, Ramanathan S, Gagnon J, Moores A, Ilangumaran S, Ferbeyre G. SOCS1 links cytokine signaling to p53 and senescence. Mol Cell 2010; 36:754-67. [PMID: 20005840 DOI: 10.1016/j.molcel.2009.09.044] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 08/14/2009] [Accepted: 09/24/2009] [Indexed: 01/22/2023]
Abstract
SOCS1 is lost in many human tumors, but its tumor suppression activities are not well understood. We report that SOCS1 is required for transcriptional activity, DNA binding, and serine 15 phosphorylation of p53 in the context of STAT5 signaling. In agreement, inactivation of SOCS1 disabled p53-dependent senescence in response to oncogenic STAT5A and radiation-induced apoptosis in T cells. In addition, SOCS1 was sufficient to induce p53-dependent senescence in fibroblasts. The mechanism of activation of p53 by SOCS1 involved a direct interaction between the SH2 domain of SOCS1 and the N-terminal transactivation domain of p53, while the C-terminal domain of SOCS1 containing the SOCS Box mediated interaction with the DNA damage-regulated kinases ATM/ATR. Also, SOCS1 colocalized with ATM at DNA damage foci induced by oncogenic STAT5A. Collectively, these results add another component to the p53 and DNA damage networks and reveal a mechanism by which SOCS1 functions as a tumor suppressor.
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Affiliation(s)
- Viviane Calabrese
- Département de Biochimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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18
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Buganim Y, Rotter V. p53: Balancing tumour suppression and implications for the clinic. Eur J Cancer 2009; 45 Suppl 1:217-34. [DOI: 10.1016/s0959-8049(09)70037-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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19
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Espinoza-Fonseca LM. Reconciling binding mechanisms of intrinsically disordered proteins. Biochem Biophys Res Commun 2009; 382:479-82. [DOI: 10.1016/j.bbrc.2009.02.151] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 02/26/2009] [Indexed: 11/15/2022]
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20
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Pavithra L, Mukherjee S, Sreenath K, Kar S, Sakaguchi K, Roy S, Chattopadhyay S. SMAR1 forms a ternary complex with p53-MDM2 and negatively regulates p53-mediated transcription. J Mol Biol 2009; 388:691-702. [PMID: 19303885 DOI: 10.1016/j.jmb.2009.03.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 03/03/2009] [Accepted: 03/09/2009] [Indexed: 10/21/2022]
Abstract
The intra-cellular level of tumor suppressor protein p53 is tightly controlled by an autoregulatory feedback loop between the protein and its negative regulator MDM2. The role of MDM2 in down-regulating the p53 response in unstressed conditions and in the post-stress recovery phase is well documented. However, interplay between the N-terminal phosphorylations and C-terminal acetylations of p53 in this context remains unclear. Here, we show that an MAR binding protein SMAR1 interacts with MDM2 and the Ser15 phosphorylated form of p53, forming a ternary complex in the post stress-recovery phase. This triple complex formation between p53, MDM2 and SMAR1 results in recruitment of HDAC1 to deacetylate p53. The deacetylated p53 binds poorly to the target promoter (p21), which results in switching off the p53 response, essential for re-entry into the cell cycle. Interestingly, the knock-down of SMAR1 using siRNA leads to a prolonged cell-cycle arrest in the post stress recovery phase due to ablation of p53-MDM2-HDAC1 interaction. Thus, the results presented here for the first time highlight the role of SMAR1 in masking the active phosphorylation site of p53, enabling the deacetylation of p53 by HDAC1-MDM2 complex, thereby regulating the p53 transcriptional response during stress rescue.
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21
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Leucine‐rich hydrophobic clusters promote folding of the N‐terminus of the intrinsically disordered transactivation domain of p53. FEBS Lett 2009; 583:556-60. [DOI: 10.1016/j.febslet.2008.12.060] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 12/08/2008] [Accepted: 12/24/2008] [Indexed: 11/18/2022]
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22
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El-Dahr SS, Aboudehen K, Dipp S. Bradykinin B2 receptor null mice harboring a Ser23-to-Ala substitution in the p53 gene are protected from renal dysgenesis. Am J Physiol Renal Physiol 2008; 295:F1404-13. [PMID: 18753293 DOI: 10.1152/ajprenal.90378.2008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A physiological cross talk operates between the tumor suppressor protein p53 and the bradykinin B2 receptor (BdkrB2) during renal organogenesis. Thus, although BdkrB2 is a target for p53-mediated transcriptional activation, BdkrB2 is required to restrict p53 proapoptotic activity. We previously demonstrated that BdkrB2(-/-) embryos exposed to gestational salt stress develop renal dysgenesis as a result of p53-mediated apoptosis of nephron progenitors and repression of the terminal differentiation program. Compared with wild-type kidneys, BdkrB2(-/-) express abnormally high levels of the Checkpoint kinase (Chk1), which activates p53 via Ser23 phosphorylation. To define the functional relevance of p53S23 phosphorylation, we generated a compound strain of BdkrB2(-/-) mice harboring a homozygous Ser23-to-Ala (S23A) mutation in the p53 gene by crossing BdkrB2(-/-) with p53S23A knockin mice. Unlike salt-stressed BdkrB2(-/-) pups, which exhibit renal dysgenesis, homozygous S23A;BdkrB2(-/-) littermates are protected and have normal renal development. Heterozygous S23A;BdkrB2(-/-) mice have an intermediate phenotype. The p53-S23A substitution was associated with amelioration of apoptosis and restored markers of nephrogenesis and tubulogenesis. Real-time quantitative RT-PCR of terminal differentiation genes demonstrated that the S23A substitution restored normal expression patterns of aquaporin-2, Na-Cl cotransporter, Na-K-2Cl cotransporter, Na-bicarbonate cotransporter, and Sglt1. We conclude that p53 phosphorylation on Ser23 is an essential step in the signaling pathway mediating the susceptibility of BdkrB2(-/-) mutants to renal dysgenesis.
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Affiliation(s)
- Samir S El-Dahr
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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23
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Espinoza-Fonseca LM, García-Machorro J. Aromatic-aromatic interactions in the formation of the MDM2-p53 complex. Biochem Biophys Res Commun 2008; 370:547-51. [PMID: 18355443 DOI: 10.1016/j.bbrc.2008.03.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 03/10/2008] [Indexed: 01/10/2023]
Abstract
Although the molecular interaction of MDM2 with the transactivation domain of p53 has been thoroughly studied, there is very limited information regarding the steps involved in the recognition mechanism between these proteins. On this basis, we performed four high-temperature molecular dynamics simulations in explicit solvent to gain insight into the interactions involved in the fist contact toward the formation of the complex. We found that the presence of specific intermolecular aromatic pairs at the interface of the complex, around the native-like state of MDM2, is consistent among independent molecular dynamics runs. This observation suggests that aromatic-aromatic interactions are closely related to the first contact between MDM2 and p53. Thus, we propose that aromatic-aromatic interactions are an important, and probably essential, requirement for the formation and stabilization of the MDM2-p53 complex.
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Affiliation(s)
- L Michel Espinoza-Fonseca
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA.
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24
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Polley S, Guha S, Roy NS, Kar S, Sakaguchi K, Chuman Y, Swaminathan V, Kundu T, Roy S. Differential recognition of phosphorylated transactivation domains of p53 by different p300 domains. J Mol Biol 2007; 376:8-12. [PMID: 18155245 DOI: 10.1016/j.jmb.2007.11.082] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 11/16/2007] [Accepted: 11/26/2007] [Indexed: 10/22/2022]
Abstract
Histone acetyltransferases form crucial links in transducing extrinsic signals to actual initiation of transcription. A multitude of stress signal integrations occur through the interaction of p300 with p53 phosphorylated at different residues of the transactivation domain. How such interactions activate different gene expression programs remains largely unknown. p300 contains at least five domains that are known to interact with p53, but their role in transcription regulation is not known. We measured the binding affinity of various phosphorylated transactivation domains towards several p53 binding domains of p300 by fluorescence anisotropy. The binding affinities of different phosphorylated transactivation domains of p53 towards different domains of p300 vary by several orders of magnitude, indicating that interactions of different post-translationally modified forms of p53 may occur through different domains of p300. Thus, different post-translationally modified p53 fragments may form transcription-initiating complexes of different configurations, leading to the activation of different promoters and pathways.
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Affiliation(s)
- Smarajit Polley
- Division of Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Kolkata 700 032, India
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25
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Lee SJ, Lim CJ, Min JK, Lee JK, Kim YM, Lee JY, Won MH, Kwon YG. Protein phosphatase 1 nuclear targeting subunit is a hypoxia inducible gene: its role in post-translational modification of p53 and MDM2. Cell Death Differ 2007; 14:1106-16. [PMID: 17318220 DOI: 10.1038/sj.cdd.4402111] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
p53, the most commonly mutated tumor suppressor gene in human cancers, is a master regulator of apoptosis in many types of cells. Recently, protein phosphatase-1 (PP1) has emerged as a key phosphatase of p53, which modulates the interaction of p53 with its regulatory protein mouse double minute 2 (MDM2) and transcriptional activity. In the present study, we demonstrate the potential role of PP1 nuclear targeting subunit (PNUTS) in regulating the phosphorylation and apoptotic activities of p53. Hypoxia significantly increased mRNA and protein expression of PNUTS in various cell lines concomitantly with increases in p53. Promoter analysis confirmed the presence of hypoxia response elements in the promoter region of the PNUTS gene, which respond to hypoxia and forced expression of hypoxia-inducible factor 1 alpha. Overexpression of PNUTS markedly increased cell death in response to hypoxia, with increased expression of Bax, an apoptosis-related gene induced by p53. Consistently, PNUTS increased the nuclear localization, phosphorylation, and transcriptional activity of p53 as well as the ubiquitin-dependent proteosomal degradation of MDM2. However, the W401A mutant form of PNUTS, which is incapable of binding to PP1, failed to induce these events. Taken together, our findings suggest that PNUTS may play an important role in controlling cell death in response to cellular stresses such as hypoxia through the post-translational modification of p53 and MDM2.
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Affiliation(s)
- S-J Lee
- Department of Biochemistry, College of Sciences, Yonsei University, Shinchon-dong, Seodaemoon-gu, Seoul, Korea
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26
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Ou YH, Chung PH, Sun TP, Shieh SY. p53 C-terminal phosphorylation by CHK1 and CHK2 participates in the regulation of DNA-damage-induced C-terminal acetylation. Mol Biol Cell 2005; 16:1684-95. [PMID: 15659650 PMCID: PMC1073652 DOI: 10.1091/mbc.e04-08-0689] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 12/14/2004] [Accepted: 01/08/2005] [Indexed: 11/11/2022] Open
Abstract
The tumor suppressor protein p53 mediates stress-induced growth arrest or apoptosis and plays a major role in safeguarding genome integrity. In response to DNA damage, p53 can be modified at multiple sites by phosphorylation and acetylation. We report on the characterization of p53 C-terminal phosphorylation by CHK1 and CHK2, two serine/threonine (Ser/Thr) protein kinases, previously implicated in the phosphorylation of the p53 N terminus. Using tryptic phosphopeptide mapping, we have identified six additional CHK1 and CHK2 sites residing in the final 100 amino acids of p53. Phosphorylation of at least three of these sites, Ser366, Ser378, and Thr387, was induced by DNA damage, and the induction at Ser366 and Thr387 was abrogated by small interfering RNA targeting chk1 and chk2. Furthermore, mutation of these phosphorylation sites has a different impact on p53 C-terminal acetylation and on the activation of p53-targeted promoters. Our results demonstrate a possible interplay between p53 C-terminal phosphorylation and acetylation, and they provide an additional mechanism for the control of the activity of p53 by CHK1 and CHK2.
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Affiliation(s)
- Yi-Hung Ou
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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27
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Reynolds R, Witherspoon S, Fox T. The infant mouse as a in vivo model for the detection and study of DNA damage-induced changes in the liver. Mol Carcinog 2004; 40:62-72. [PMID: 15108330 DOI: 10.1002/mc.20017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present work describes the use of the infant (4-wk-old) mouse as an animal model for the study of DNA damage-induced G(1) checkpoint response, changes in p53 protein levels, and multiple gene expression changes after DNA damage has been induced in the liver. Hepatocytes in the infant B6C3F1 mouse had a proliferation index that was 27 times greater than that of the 12-wk-old B6C3F1 mouse (57.4 vs. 2.1%, respectively). Eight hours after infant mice were exposed to the DNA damaging agents bleomycin (100 mg/kg, i.p.) or 10 Gy of whole body gamma irradiation, the G(1)/S ratio significantly increased from 21 (control) to 66 and 75, respectively, because of the induction of the G(1)/S checkpoint response. One hour after whole body irradiation of infant mice the levels of the p53 protein, phosphoserine 18-p53 and phosphoserine 23-p53 increased dramatically and tended to peak at 1 h in the liver, whereas the p21(WAF1) protein increased more slowly and tended to peak at 2 h after irradiation. The mRNA expression of the p53-response genes p21, murine double minute clone 2 (mdm2), and cyclin G was increased at 2 h after irradiation but was decreased by 8 h postirradiation, relative to the 2-h time-point. The expression of insulin-like growth factor binding protein-1 (IGFBP-1) and growth-regulated oncogene 1 (GRO1) increased at 2 and 8 h postirradiation. This work characterizes various parameters in the infant mouse, thus validating the use of this model to study in vivo DNA damage-induced cell-cycle-related changes.
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Affiliation(s)
- Randall Reynolds
- Department of Comparative Biomedical Sciences, North Carolina State University, Raleigh, North Carolina, USA
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28
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Schultz L, Khera S, Sleve D, Heath J, Chang NS. TIAF1 and p53 functionally interact in mediating apoptosis and silencing of TIAF1 abolishes nuclear translocation of serine 15-phosphorylated p53. DNA Cell Biol 2004; 23:67-74. [PMID: 14965474 DOI: 10.1089/104454904322745943] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
TIAF1 is a TGF-beta 1-induced factor that protects L929 fibroblasts from TNF-mediated apoptosis. In contrast, overexpressed TIAF1 induces growth inhibition and apoptosis of monocytic U937 and various nonfibroblast cells. TIAF1-mediated apoptosis of U937 cells involves upregulation of p53, p21, and Smad2/4, but downregulation of ERK phosphorylation. To determine whether p53 and TIAF1 functionally interact in regulating cell death, ectopic TIAF1 and p53 were shown to induce apoptosis of U937 cells in both synergistic and antagonistic manners. At optimal levels both TIAF1 and p53 mediated apoptosis cooperatively. Also, both proteins suppressed adherence-independent growth of L929 cells. In contrast, initiation of apoptosis by overexpressed TIAF1 was blocked by low doses of p53, and vice versa. Furthermore, ectopic p53 blocked an ongoing apoptosis in U937 cells stably expressing TIAF1. Yeast two-hybrid analyses failed to demonstrate the binding of p53 with TIAF1, suggesting an unidentified protein that links the p53/TIFA1 interaction. Suppression of TIAF1 expression by siRNA could not inhibit Ser15 phosphorylation in p53 in response to UV and etoposide. However, nuclear translocation of these Ser15-phosphorylated p53 was significantly reduced in TIAF1-silenced cells. Taken together, TIAF1 and p53 functionally interact in regulating apoptosis, and TIAF1 is likely to participate in the nuclear translocation of activated p53.
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Affiliation(s)
- Lori Schultz
- Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, Pennsylvania, USA
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29
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Jackson MW, Agarwal MK, Agarwal ML, Agarwal A, Stanhope-Baker P, Williams BRG, Stark GR. Limited role of N-terminal phosphoserine residues in the activation of transcription by p53. Oncogene 2004; 23:4477-87. [PMID: 15064747 DOI: 10.1038/sj.onc.1207575] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The p53 tumor suppressor is phosphorylated in response to various cellular stress signals, such as DNA damage, leading to its release from MDM2 and consequent stabilization and activation as a transcription factor. In human U2OS cells, treatment with adriamycin causes p53 to be phosphorylated on all six serine residues tested, leading to the dissociation of p53 from MDM2 and transcription of the p21 and mdm2 genes. In contrast, in these cells, IPTG-dependent induction of p14ARF, which sequesters MDM2 away from p53, does not lead to detectable phosphorylation of any of the five N-terminal serine residues tested (6, 9, 15, 20, 37). Only C-terminal serine 392 is phosphorylated. However, the increase of p21 and mdm2 mRNAs was indistinguishable following treatment with adriamycin or induction of p14ARF. By using cDNA arrays to examine global p53-dependent gene expression in response to adriamycin or p14ARF, we found that most genes were regulated similarly by the two treatments. However, a subset of p53-regulated genes whose products have proliferative roles or regulate VEGF activity, newly described here, are repressed by p14ARF much more than by adriamycin. We conclude that the phosphorylation of p53 on N-terminal serine residues is not required for increased transcription of the great majority of p53-responsive genes and that the induction of p53 by p14ARF, with little phosphorylation, leads to substantial repression of genes whose products have roles in proliferation.
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Affiliation(s)
- Mark W Jackson
- Department of Molecular Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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30
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Knights CD, Liu Y, Appella E, Kulesz-Martin M. Defective p53 Post-translational Modification Required for Wild Type p53 Inactivation in Malignant Epithelial Cells with mdm2 Gene Amplification. J Biol Chem 2003; 278:52890-900. [PMID: 14555661 DOI: 10.1074/jbc.m300279200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Mdm2 gene amplification occurs in benign and chemotherapy-responsive malignant tumors with wtp53 genes as well as in breast and epithelial cancers. Mdm2 amplification in benign tumors suggests that it is not sufficient for p53 inactivation in cancer, implying that other defects in the p53 pathway are required for malignancy. We investigated mechanisms of wtp53 protein inactivation in malignant conversion of epithelial cells by comparing clonally related initiated cells with their derivative cancerous cells that have mdm2 amplification. Deficiencies in p53 accumulation and activities in response to DNA damage were not due simply to Mdm2 destabilization of p53 protein, but to continued association of DNA-bound p53 with Mdm2 protein and lack of binding and acetylation by p300 protein. The aberrant interactions were not because of mdm2 amplification alone, because DNA-bound p53 protein from initiated cells failed to bind ectopically expressed Mdm2 or endogenous overexpressed Mdm2 from cancerous cells. Phosphorylations of endogenous p53 at Ser18, -23, or -37 were insufficient to dissociate Mdm2, because each was induced by UV in cancerous cells. Interestingly, phospho-mimic p53-T21E did dissociate the Mdm2 protein from DNA-bound p53 and recovered p300 binding and p21 induction in the cancerous cells. Thus wtp53 in malignant cells with mdm2 amplification can be inactivated by continued association of DNA-bound p53 protein with Mdm2 and failure of p300 binding and acetylation, coupled with a defect in p53 phosphorylation at Thr21. These findings suggest therapeutic strategies that address both p53/Mdm2 interaction and associated p53 protein defects in human tumors that have amplified mdm2 genes.
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Affiliation(s)
- Chad D Knights
- Department of Dermatology, Oregon Health & Science University, Portland, Oregon 97239, USA
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31
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Varadi G, Otvos L. Synthesis of complex phosphopeptides as mimics of p53 functional domains. J Pept Sci 2002; 8:621-33. [PMID: 12487430 DOI: 10.1002/psc.422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A complete set of mono-, di- and triphosphorylated peptides comprising amino acids 10-27, the Mdm2 and p300 binding site(s) of p53, with and without a fluorescein label at the N-terminus, was synthesized by step-by-step solid phase synthesis. Fluorescence polarization analysis revealed that phosphorylation at Thr18 decreased binding to recombinant Mdm2 protein compared with the unphosphorylated and the two other single phosphorylated analogues. Unlabelled multiply phosphorylated peptides corresponding to this amino-terminal transactivation domain proved to be powerful tools in analysing the phosphate specificity of existing anti-p53 monoclonal and polyclonal antibodies using direct ELISA. The tetramerization domain of human p53 protein was modelled with a 53 residue-long unlabelled unphosphorylated and Ser315-phosphorylated peptide pair. CD analysis showed similar alpha-helical structures for both peptides and no major difference in the secondary structure could be observed upon phosphorylation. Size-exclusion HPLC indicated that these synthetic oligomerization domain mimics underwent a pH-dependent tetramerization process, but the presence of a phosphate group at Ser315 did not modify the oligomeric state of the 308-360 p53 fragments. Nevertheless, the fluorescein-labelled Ser315 phosphorylated peptide bound to the downstream signalling ligand DNA topoisomerase I protein with slightly higher affinity than did the unphosphorylated analogue.
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Affiliation(s)
- Gyorgyi Varadi
- The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, USA.
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Chouinard N, Valerie K, Rouabhia M, Huot J. UVB-mediated activation of p38 mitogen-activated protein kinase enhances resistance of normal human keratinocytes to apoptosis by stabilizing cytoplasmic p53. Biochem J 2002; 365:133-45. [PMID: 12071847 PMCID: PMC1222664 DOI: 10.1042/bj20020072] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human keratinocytes respond to UV rays by developing a fast adaptive response that contributes to maintaining their functions and survival. We investigated the role of the mitogen-activated protein kinase pathways in transducing the UV signals in normal human keratinocytes. We found that UVA, UVB or UVC induced a marked and persistent activation of p38, whereas c-Jun N-terminal kinase or extracellular signal-regulated kinase were less or not activated respectively. Inhibition of p38 activity by expression of a dominant-negative mutant of p38 or with SB203580 impaired cell viability and led to an increase in UVB-induced apoptosis. This sensitization to apoptosis was independent of caspase activities. Inhibition of p38 did not sensitize transformed HaCaT keratinocytes to UVB-induced apoptosis. In normal keratinocytes, expression of a dominant-negative mutant of p53 increased UVB-induced cell death, pointing to a role for p53. In these cells, UVB triggered a p38-dependent phosphorylation of p53 on Ser-15. This phosphorylation was associated with an SB203580-sensitive accumulation of p53, even in the presence of a serine phosphatase inhibitor. Accumulated p53 was localized mainly in the cytoplasm, independently of CRM1 nuclear export. In HaCaT cells, p53 was localized exclusively in the nucleus and its distribution and level were not affected by UVB or p38 inhibition. However, UVB induced an SB203580-insensitive phosphorylation on Ser-15 of mutated p53. Overall, our results suggest that, in normal human keratinocytes, protection against UVB depends on p38-mediated phosphorylation and stabilization of p53 and is tightly associated with the cytoplasmic sequestration of wild-type p53. We conclude that the p38/p53 pathway plays a key role in the adaptive response of normal human keratinocytes against UV stress.
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Affiliation(s)
- Nadine Chouinard
- Unité de biotechnologie, Centre de recherche de l'Hôpital St-François d'Assise de Québec, 10 rue de l'Espinay, Québec G1L-3L5, Canada.
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