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Usher ET, Fossat MJ, Holehouse AS. Phosphorylation of disordered proteins tunes local and global intramolecular interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.10.598315. [PMID: 38915510 PMCID: PMC11195077 DOI: 10.1101/2024.06.10.598315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Protein post-translational modifications, such as phosphorylation, are important regulatory signals for diverse cellular functions. In particular, intrinsically disordered protein regions (IDRs) are subject to phosphorylation as a means to modulate their interactions and functions. Toward understanding the relationship between phosphorylation in IDRs and specific functional outcomes, we must consider how phosphorylation affects the IDR conformational ensemble. Various experimental techniques are suited to interrogate the features of IDR ensembles; molecular simulations can provide complementary insights and even illuminate ensemble features that may be experimentally inaccessible. Therefore, we sought to expand the tools available to study phosphorylated IDRs by all-atom Monte Carlo simulations. To this end, we implemented parameters for phosphoserine (pSer) and phosphothreonine (pThr) into the OPLS version of the continuum solvent model, ABSINTH, and assessed their performance in all-atom simulations compared to published findings. We simulated short (< 20 residues) and long (> 80 residues) phospho-IDRs that, collectively, survey both local and global phosphorylation-induced changes to the ensemble. Our simulations of four well-studied phospho-IDRs show near-quantitative agreement with published findings for these systems via metrics including changes to radius of gyration, transient helicity, and persistence length. We also leveraged the inherent advantage of sequence control in molecular simulations to explore the conformational effects of diverse combinations of phospho-sites in two multi-phosphorylated IDRs. Our results support and expand on prior observations that connect phosphorylation to changes in the IDR conformational ensemble. Herein, we describe phosphorylation as a means to alter sequence chemistry, net charge and charge patterning, and intramolecular interactions, which can collectively modulate the local and global IDR ensemble features.
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Affiliation(s)
- Emery T. Usher
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO, USA
| | - Martin J. Fossat
- Department of Biological Physics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO, USA
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2
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Modic M, Adamek M, Ule J. The impact of IDR phosphorylation on the RNA binding profiles of proteins. Trends Genet 2024:S0168-9525(24)00078-7. [PMID: 38705823 DOI: 10.1016/j.tig.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 05/07/2024]
Abstract
Due to their capacity to mediate repetitive protein interactions, intrinsically disordered regions (IDRs) are crucial for the formation of various types of protein-RNA complexes. The functions of IDRs are strongly modulated by post-translational modifications (PTMs). Phosphorylation is the most common and well-studied modification of IDRs, which can alter homomeric or heteromeric interactions of proteins and impact their ability to phase separate. Moreover, phosphorylation can influence the RNA-binding properties of proteins, and recent studies demonstrated its selective impact on the global profiles of protein-RNA binding and regulation. These findings highlight the need for further integrative approaches to understand how signalling remodels protein-RNA networks in cells.
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Affiliation(s)
- Miha Modic
- National Institute of Chemistry, Ljubljana, Slovenia; The Francis Crick Institute, London, UK; UK Dementia Research Institute at King's College London, London, UK.
| | - Maksimiljan Adamek
- National Institute of Chemistry, Ljubljana, Slovenia; PhD Program 'Biosciences', Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Ule
- National Institute of Chemistry, Ljubljana, Slovenia; The Francis Crick Institute, London, UK; UK Dementia Research Institute at King's College London, London, UK.
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3
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Dey D, Qing E, He Y, Chen Y, Jennings B, Cohn W, Singh S, Gakhar L, Schnicker NJ, Pierce BG, Whitelegge JP, Doray B, Orban J, Gallagher T, Hasan SS. A single C-terminal residue controls SARS-CoV-2 spike trafficking and incorporation into VLPs. Nat Commun 2023; 14:8358. [PMID: 38102143 PMCID: PMC10724246 DOI: 10.1038/s41467-023-44076-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023] Open
Abstract
The spike (S) protein of SARS-CoV-2 is delivered to the virion assembly site in the ER-Golgi Intermediate Compartment (ERGIC) from both the ER and cis-Golgi in infected cells. However, the relevance and modulatory mechanism of this bidirectional trafficking are unclear. Here, using structure-function analyses, we show that S incorporation into virus-like particles (VLP) and VLP fusogenicity are determined by coatomer-dependent S delivery from the cis-Golgi and restricted by S-coatomer dissociation. Although S mimicry of the host coatomer-binding dibasic motif ensures retrograde trafficking to the ERGIC, avoidance of the host-like C-terminal acidic residue is critical for S-coatomer dissociation and therefore incorporation into virions or export for cell-cell fusion. Because this C-terminal residue is the key determinant of SARS-CoV-2 assembly and fusogenicity, our work provides a framework for the export of S protein encoded in genetic vaccines for surface display and immune activation.
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Affiliation(s)
- Debajit Dey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Enya Qing
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Yanan He
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, 20850, USA
| | - Yihong Chen
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, 20850, USA
| | - Benjamin Jennings
- Department of Internal Medicine, Hematology Division, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Whitaker Cohn
- Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Suruchi Singh
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Lokesh Gakhar
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
- PAQ Therapeutics, Burlington, MA, 01803, USA
| | - Nicholas J Schnicker
- Protein and Crystallography Facility, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Brian G Pierce
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, 20850, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Julian P Whitelegge
- Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Balraj Doray
- Department of Internal Medicine, Hematology Division, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - John Orban
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, 20850, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Tom Gallagher
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, 60153, USA
| | - S Saif Hasan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, Baltimore, MD, 21201, USA.
- Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Rockville, MD, 20850, USA.
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4
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Tsangaris TE, Smyth S, Gomes GNW, Liu ZH, Milchberg M, Bah A, Wasney GA, Forman-Kay JD, Gradinaru CC. Delineating Structural Propensities of the 4E-BP2 Protein via Integrative Modeling and Clustering. J Phys Chem B 2023; 127:7472-7486. [PMID: 37595014 PMCID: PMC10858721 DOI: 10.1021/acs.jpcb.3c04052] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
The intrinsically disordered 4E-BP2 protein regulates mRNA cap-dependent translation through interaction with the predominantly folded eukaryotic initiation factor 4E (eIF4E). Phosphorylation of 4E-BP2 dramatically reduces the level of eIF4E binding, in part by stabilizing a binding-incompatible folded domain. Here, we used a Rosetta-based sampling algorithm optimized for IDRs to generate initial ensembles for two phospho forms of 4E-BP2, non- and 5-fold phosphorylated (NP and 5P, respectively), with the 5P folded domain flanked by N- and C-terminal IDRs (N-IDR and C-IDR, respectively). We then applied an integrative Bayesian approach to obtain NP and 5P conformational ensembles that agree with experimental data from nuclear magnetic resonance, small-angle X-ray scattering, and single-molecule Förster resonance energy transfer (smFRET). For the NP state, inter-residue distance scaling and 2D maps revealed the role of charge segregation and pi interactions in driving contacts between distal regions of the chain (∼70 residues apart). The 5P ensemble shows prominent contacts of the N-IDR region with the two phosphosites in the folded domain, pT37 and pT46, and, to a lesser extent, delocalized interactions with the C-IDR region. Agglomerative hierarchical clustering led to partitioning of each of the two ensembles into four clusters with different global dimensions and contact maps. This helped delineate an NP cluster that, based on our smFRET data, is compatible with the eIF4E-bound state. 5P clusters were differentiated by interactions of C-IDR with the folded domain and of the N-IDR with the two phosphosites in the folded domain. Our study provides both a better visualization of fundamental structural poses of 4E-BP2 and a set of falsifiable insights on intrachain interactions that bias folding and binding of this protein.
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Affiliation(s)
- Thomas E Tsangaris
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Spencer Smyth
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Gregory-Neal W Gomes
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Zi Hao Liu
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Moses Milchberg
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Alaji Bah
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Gregory A Wasney
- Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Julie D Forman-Kay
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
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Kulkarni P, Salgia R, Rangarajan G. Intrinsically disordered proteins and conformational noise: The hypothesis a decade later. iScience 2023; 26:107109. [PMID: 37408690 PMCID: PMC10319216 DOI: 10.1016/j.isci.2023.107109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023] Open
Abstract
Phenotypic plasticity is the ability of individual genotypes to produce different phenotypes in response to environmental perturbations. We previously postulated how conformational noise emanating from conformational dynamics of intrinsically disordered proteins (IDPs) which is distinct from transcriptional noise, can contribute to phenotypic switching by rewiring the cellular protein interaction network. Since most transcription factors are IDPs, we posited that conformational noise is an integral component of transcriptional noise implying that IDPs may amplify total noise in the system either stochastically or in response to environmental changes. Here, we review progress in elucidating the details of the hypothesis. We highlight empirical evidence supporting the hypothesis, discuss conceptual advances that underscore its fundamental importance and implications, and identify areas for future investigations.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
- Department of Systems Biology, City of Hope National Medical Center, Duarte, CA, USA
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
- Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
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6
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Illuminating Intrinsically Disordered Proteins with Integrative Structural Biology. Biomolecules 2023; 13:biom13010124. [PMID: 36671509 PMCID: PMC9856150 DOI: 10.3390/biom13010124] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/01/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Intense study of intrinsically disordered proteins (IDPs) did not begin in earnest until the late 1990s when a few groups, working independently, convinced the community that these 'weird' proteins could have important functions. Over the past two decades, it has become clear that IDPs play critical roles in a multitude of biological phenomena with prominent examples including coordination in signaling hubs, enabling gene regulation, and regulating ion channels, just to name a few. One contributing factor that delayed appreciation of IDP functional significance is the experimental difficulty in characterizing their dynamic conformations. The combined application of multiple methods, termed integrative structural biology, has emerged as an essential approach to understanding IDP phenomena. Here, we review some of the recent applications of the integrative structural biology philosophy to study IDPs.
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7
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Kulkarni P, Bhattacharya S, Achuthan S, Behal A, Jolly MK, Kotnala S, Mohanty A, Rangarajan G, Salgia R, Uversky V. Intrinsically Disordered Proteins: Critical Components of the Wetware. Chem Rev 2022; 122:6614-6633. [PMID: 35170314 PMCID: PMC9250291 DOI: 10.1021/acs.chemrev.1c00848] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite the wealth of knowledge gained about intrinsically disordered proteins (IDPs) since their discovery, there are several aspects that remain unexplored and, hence, poorly understood. A living cell is a complex adaptive system that can be described as a wetware─a metaphor used to describe the cell as a computer comprising both hardware and software and attuned to logic gates─capable of "making" decisions. In this focused Review, we discuss how IDPs, as critical components of the wetware, influence cell-fate decisions by wiring protein interaction networks to keep them minimally frustrated. Because IDPs lie between order and chaos, we explore the possibility that they can be modeled as attractors. Further, we discuss how the conformational dynamics of IDPs manifests itself as conformational noise, which can potentially amplify transcriptional noise to stochastically switch cellular phenotypes. Finally, we explore the potential role of IDPs in prebiotic evolution, in forming proteinaceous membrane-less organelles, in the origin of multicellularity, and in protein conformation-based transgenerational inheritance of acquired characteristics. Together, these ideas provide a new conceptual framework to discern how IDPs may perform critical biological functions despite their lack of structure.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
- Address for correspondence: Prakash Kulkarni, Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, , Vladimir N. Uversky, Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612,
| | - Supriyo Bhattacharya
- Integrative Genomics Core, City of Hope National Medical Center, Duarte, CA, USA
| | - Srisairam Achuthan
- Division of Research Informatics, Center for Informatics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Amita Behal
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sourabh Kotnala
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
- Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Vladimir Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow region 141700, Russia
- Address for correspondence: Prakash Kulkarni, Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, , Vladimir N. Uversky, Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612,
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8
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Kulkarni P, Leite VBP, Roy S, Bhattacharyya S, Mohanty A, Achuthan S, Singh D, Appadurai R, Rangarajan G, Weninger K, Orban J, Srivastava A, Jolly MK, Onuchic JN, Uversky VN, Salgia R. Intrinsically disordered proteins: Ensembles at the limits of Anfinsen's dogma. BIOPHYSICS REVIEWS 2022; 3:011306. [PMID: 38505224 PMCID: PMC10903413 DOI: 10.1063/5.0080512] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/17/2022] [Indexed: 03/21/2024]
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack rigid 3D structure. Hence, they are often misconceived to present a challenge to Anfinsen's dogma. However, IDPs exist as ensembles that sample a quasi-continuum of rapidly interconverting conformations and, as such, may represent proteins at the extreme limit of the Anfinsen postulate. IDPs play important biological roles and are key components of the cellular protein interaction network (PIN). Many IDPs can interconvert between disordered and ordered states as they bind to appropriate partners. Conformational dynamics of IDPs contribute to conformational noise in the cell. Thus, the dysregulation of IDPs contributes to increased noise and "promiscuous" interactions. This leads to PIN rewiring to output an appropriate response underscoring the critical role of IDPs in cellular decision making. Nonetheless, IDPs are not easily tractable experimentally. Furthermore, in the absence of a reference conformation, discerning the energy landscape representation of the weakly funneled IDPs in terms of reaction coordinates is challenging. To understand conformational dynamics in real time and decipher how IDPs recognize multiple binding partners with high specificity, several sophisticated knowledge-based and physics-based in silico sampling techniques have been developed. Here, using specific examples, we highlight recent advances in energy landscape visualization and molecular dynamics simulations to discern conformational dynamics and discuss how the conformational preferences of IDPs modulate their function, especially in phenotypic switching. Finally, we discuss recent progress in identifying small molecules targeting IDPs underscoring the potential therapeutic value of IDPs. Understanding structure and function of IDPs can not only provide new insight on cellular decision making but may also help to refine and extend Anfinsen's structure/function paradigm.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Vitor B. P. Leite
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo 15054-000, Brazil
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Supriyo Bhattacharyya
- Translational Bioinformatics, Center for Informatics, Department of Computational and Quantitative Medicine, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Srisairam Achuthan
- Center for Informatics, Division of Research Informatics, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Divyoj Singh
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Rajeswari Appadurai
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | | | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Jose N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005-1892, USA
| | | | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
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9
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Sadar MD. Drugging the Undruggable: Targeting the N-Terminal Domain of Nuclear Hormone Receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:311-326. [PMID: 36107327 DOI: 10.1007/978-3-031-11836-4_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This chapter focuses on the development of drugs targeting the N-terminal domain of nuclear hormone receptors, using progress with the androgen receptor as an example. Historically, development of therapies targeting nuclear hormone receptors has focused on the folded C-terminal ligand-binding domain. Therapies were traditionally not developed to target the intrinsically disordered N-terminal domain as it was considered "undruggable". Recent developments have now shown it is possible to direct therapies to the N-terminal domain. This chapter will provide an introduction of the structure and function of the domains of nuclear hormone receptors, followed by a discussion of the rationale supporting the development of N-terminal domain inhibitors. Chemistry and mechanisms of action of small molecule inhibitors will be described with emphasis on N-terminal domain inhibitors developed to the androgen receptor including those in clinical trials.
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Affiliation(s)
- Marianne D Sadar
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer, Vancouver, BC, Canada.
- Department of Pathology and Laboratory Science, University of British Columbia, Vancouver, BC, Canada.
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10
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Protein conformational dynamics and phenotypic switching. Biophys Rev 2021; 13:1127-1138. [PMID: 35059032 PMCID: PMC8724335 DOI: 10.1007/s12551-021-00858-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/18/2021] [Indexed: 12/14/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack rigid 3D structure but exist as conformational ensembles. Because of their structural plasticity, they can interact with multiple partners. The protein interactions between IDPs and their partners form scale-free protein interaction networks (PINs) that facilitate information flow in the cell. Because of their plasticity, IDPs typically occupy hub positions in cellular PINs. Furthermore, their conformational dynamics and propensity for post-translational modifications contribute to "conformational" noise which is distinct from the well-recognized transcriptional noise. Therefore, upregulation of IDPs in response to a specific input, such as stress, contributes to increased noise and, hence, an increase in stochastic, "promiscuous" interactions. These interactions lead to activation of latent pathways or can induce "rewiring" of the PIN to yield an optimal output underscoring the critical role of IDPs in regulating information flow. We have used PAGE4, a highly intrinsically disordered stress-response protein as a paradigm. Employing a variety of experimental and computational techniques, we have elucidated the role of PAGE4 in phenotypic switching of prostate cancer cells at a systems level. These cumulative studies over the past decade provide a conceptual framework to better understand how IDP conformational dynamics and conformational noise might facilitate cellular decision-making.
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11
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Oliveira Junior AB, Lin X, Kulkarni P, Onuchic JN, Roy S, Leite VBP. Exploring Energy Landscapes of Intrinsically Disordered Proteins: Insights into Functional Mechanisms. J Chem Theory Comput 2021; 17:3178-3187. [PMID: 33871257 DOI: 10.1021/acs.jctc.1c00027] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intrinsically disordered proteins (IDPs) lack a rigid three-dimensional structure and populate a polymorphic ensemble of conformations. Because of the lack of a reference conformation, their energy landscape representation in terms of reaction coordinates presents a daunting challenge. Here, our newly developed energy landscape visualization method (ELViM), a reaction coordinate-free approach, shows its prime application to explore frustrated energy landscapes of an intrinsically disordered protein, prostate-associated gene 4 (PAGE4). PAGE4 is a transcriptional coactivator that potentiates the oncogene c-Jun. Two kinases, namely, HIPK1 and CLK2, phosphorylate PAGE4, generating variants phosphorylated at different serine/threonine residues (HIPK1-PAGE4 and CLK2-PAGE4, respectively) with opposing functions. While HIPK1-PAGE4 predominantly phosphorylates Thr51 and potentiates c-Jun, CLK2-PAGE4 hyperphosphorylates PAGE4 and attenuates transactivation. To understand the underlying mechanisms of conformational diversity among different phosphoforms, we have analyzed their atomistic trajectories simulated using AWSEM forcefield, and the energy landscapes were elucidated using ELViM. This method allows us to identify and compare the population distributions of different conformational ensembles of PAGE4 phosphoforms using the same effective phase space. The results reveal a predominant conformational ensemble with an extended C-terminal segment of WT PAGE4, which exposes a functional residue Thr51, implying its potential of undertaking a fly-casting mechanism while binding to its cognate partner. In contrast, for HIPK1-PAGE4, a compact conformational ensemble enhances its population sequestering phosphorylated-Thr51. This clearly explains the experimentally observed weaker affinity of HIPK1-PAGE4 for c-Jun. ELViM appears as a powerful tool, especially to analyze the highly frustrated energy landscape representation of IDPs where appropriate reaction coordinates are hard to apprehend.
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Affiliation(s)
- Antonio B Oliveira Junior
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005-1892, United States
| | - Xingcheng Lin
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, United States
| | - Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, United States
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005-1892, United States
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Vitor B P Leite
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo 15054-000, Brazil
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12
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Li XF, Ren P, Shen WZ, Jin X, Zhang J. The expression, modulation and use of cancer-testis antigens as potential biomarkers for cancer immunotherapy. Am J Transl Res 2020; 12:7002-7019. [PMID: 33312347 PMCID: PMC7724325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/19/2020] [Indexed: 06/12/2023]
Abstract
Cancer-testis antigens (CTA) are tumor antigens, present in the germ cells of testes, ovaries and trophoblasts, which undergo deregulated expression in the tumor and malignant cells. CTA genes are either X-linked or autosomal, favourably expressed in spermatogonia and spermatocytes, respectively. CTAs trigger unprompted humoral immunity and immune responses in malignancies, altering tumor cell physiology and neoplastic behaviors. CTAs demonstrate varied expression profile, with increased abundance in malignant melanoma and prostate, lung, breast and epithelial cell cancers, and a relatively reduced prevalence in intestinal cancer, renal cell adenocarcinoma and malignancies of immune cells. A combination of epigenetic and non-epigenetic agents regulates CTA mRNA expression, with the key participation of CpG islands and CpG-rich promoters, histone methyltransferases, cytokines, tyrosine kinases and transcriptional activators and repressors. CTA triggers gametogenesis, in association with mutated tumorigenic genes and tumor repressors. The CTAs function as potential biomarkers, particularly for prostate, cervical, breast, colorectal, gastric, urinary bladder, liver and lung carcinomas, characterized by alternate splicing and phenotypic heterogeneity in the cells. Additionally, CTAs are prospective targets for vaccine therapy, with the MAGE-A3 and NYESO-1 undergoing clinical trials for tumor regression in malignant melanoma. They have been deemed important for adaptive immunotherapy, marked by limited expression in normal somatic tissues and recurrent up-regulation in epithelial carcinoma. Overall, the current review delineates an up-dated understanding of the intricate processes of CTA expression and regulation in cancer. It further portrays the role of CTAs as biomarkers and probable candidates for tumor immunotherapy, with a future prospect in cancer treatment.
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Affiliation(s)
- Xiao-Feng Li
- Department of Respiratory Medicine, The Second Hospital of Jilin UniversityChangchun, P. R. China
- Department of Oncology and Hematology, The Second Hospital of Jilin UniversityChangchun, P. R. China
| | - Ping Ren
- Department of Thoracic Surgery, The First Hospital of Jilin UniversityChangchun, P. R. China
| | - Wei-Zhang Shen
- Department of Oncology and Hematology, The Second Hospital of Jilin UniversityChangchun, P. R. China
| | - Xin Jin
- Department of Oncology and Hematology, The Second Hospital of Jilin UniversityChangchun, P. R. China
| | - Jie Zhang
- Department of Respiratory Medicine, The Second Hospital of Jilin UniversityChangchun, P. R. China
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13
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Kulkarni P. Intrinsically Disordered Proteins: Insights from Poincaré, Waddington, and Lamarck. Biomolecules 2020; 10:biom10111490. [PMID: 33126482 PMCID: PMC7692701 DOI: 10.3390/biom10111490] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 10/12/2020] [Indexed: 12/28/2022] Open
Abstract
The past quarter-century may justly be referred to as a period analogous to the “Cambrian explosion” in the history of proteins. This period is marked by the appearance of the intrinsically disordered proteins (IDPs) on the scene since their discovery in the mid-1990s. Here, I first reflect on how we accidentally stumbled on these fascinating molecules. Next, I describe our research on the IDPs over the past decade and identify six areas as important for future research in this field. In addition, I draw on discoveries others in the field have made to present a more comprehensive essay. More specifically, I discuss the role of IDPs in two fundamental aspects of life: in phenotypic switching, and in multicellularity that marks one of the major evolutionary transitions. I highlight how serendipity, imagination, and an interdisciplinary approach embodying empirical evidence and theoretical insights from the works of Poincaré, Waddington, and Lamarck, shaped our thinking, and how this led us to propose the MRK hypothesis, a conceptual framework addressing phenotypic switching, the emergence of new traits, and adaptive evolution via nongenetic and IDP conformation-based mechanisms. Finally, I present a perspective on the evolutionary link between phenotypic switching and the origin of multicellularity.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Experimental Therapeutics, City of Hope, National Medical Center, Duarte, CA 91010, USA
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14
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A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin. Biomolecules 2020; 10:biom10091313. [PMID: 32933064 PMCID: PMC7565984 DOI: 10.3390/biom10091313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-1H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.
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15
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Tsytlonok M, Hemmen K, Hamilton G, Kolimi N, Felekyan S, Seidel CAM, Tompa P, Sanabria H. Specific Conformational Dynamics and Expansion Underpin a Multi-Step Mechanism for Specific Binding of p27 with Cdk2/Cyclin A. J Mol Biol 2020; 432:2998-3017. [PMID: 32088186 PMCID: PMC7254055 DOI: 10.1016/j.jmb.2020.02.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/27/2020] [Accepted: 02/09/2020] [Indexed: 12/12/2022]
Abstract
The protein p27, a prominent regulatory protein in eukaryotes and an intrinsically disordered protein (IDP), regulates cell division by causing cell cycle arrest when bound in ternary complex with cyclin-dependent kinase (Cdk2) and cyclins (e.g., Cdk2/Cyclin A). We present an integrative study of p27 and its binding to Cdk2/Cyclin A complex by performing single-molecule multiparameter fluorescence spectroscopy, stopped-flow experiments, and molecular dynamics simulations. Our results suggest that unbound p27 adopts a compact conformation and undergoes conformational dynamics across several orders of magnitude in time (nano-to milliseconds), reflecting a multi-step mechanism for binding Cdk2/Cyclin A. Mutagenesis studies reveal that the region D1 in p27 plays a significant role in mediating the association kinetics, undergoing conformational rearrangement upon initial binding. Additionally, FRET experiments indicate an expansion of p27 throughout binding. The detected local and long-range structural dynamics suggest that p27 exhibits a limited binding surface in the unbound form, and stochastic conformational changes in D1 facilitate initial binding to Cdk2/Cyclin A complex. Furthermore, the post-kinase inhibitory domain (post-KID) region of p27 exchanges between distinct conformational ensembles: an extended regime exhibiting worm-like chain behavior, and a compact ensemble, which may protect p27 against nonspecific interactions. In summary, the binding interaction involves three steps: (i) D1 initiates binding, (ii) p27 wraps around Cdk2/Cyclin A and D2 binds, and (iii) the fully-formed fuzzy ternary complex is formed concomitantly with an extension of the post-KID region. An understanding of how the IDP nature of p27 underpins its functional interactions with Cdk2/Cyclin A provides insight into the complex binding mechanisms of IDPs and their regulatory mechanisms.
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Affiliation(s)
- Maksym Tsytlonok
- VIB-VUB Center for Structural Biology (CSB), Vrije Universiteit Brussel, Brussels, Belgium
| | - Katherina Hemmen
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225, Düsseldorf, Germany; Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, 97078, Würzburg, Germany
| | - George Hamilton
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Narendar Kolimi
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Suren Felekyan
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225, Düsseldorf, Germany
| | - Claus A M Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225, Düsseldorf, Germany
| | - Peter Tompa
- VIB-VUB Center for Structural Biology (CSB), Vrije Universiteit Brussel, Brussels, Belgium; Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Hugo Sanabria
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225, Düsseldorf, Germany; Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA.
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16
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Pu W, Zheng Y, Peng Y. Prolyl Isomerase Pin1 in Human Cancer: Function, Mechanism, and Significance. Front Cell Dev Biol 2020; 8:168. [PMID: 32296699 PMCID: PMC7136398 DOI: 10.3389/fcell.2020.00168] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/29/2020] [Indexed: 02/05/2023] Open
Abstract
Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is an evolutionally conserved and unique enzyme that specifically catalyzes the cis-trans isomerization of phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif and, subsequently, induces the conformational change of its substrates. Mounting evidence has demonstrated that Pin1 is widely overexpressed and/or overactivated in cancer, exerting a critical influence on tumor initiation and progression via regulation of the biological activity, protein degradation, or nucleus-cytoplasmic distribution of its substrates. Moreover, Pin1 participates in the cancer hallmarks through activating some oncogenes and growth enhancers, or inactivating some tumor suppressors and growth inhibitors, suggesting that Pin1 could be an attractive target for cancer therapy. In this review, we summarize the findings on the dysregulation, mechanisms, and biological functions of Pin1 in cancer cells, and also discuss the significance and potential applications of Pin1 dysregulation in human cancer.
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Affiliation(s)
- Wenchen Pu
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
| | - Yuanyuan Zheng
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
| | - Yong Peng
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
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17
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Fu S, Liu T, Lv C, Fu C, Zeng R, Kakehi Y, Kulkarni P, Getzenberg RH, Zeng Y. Stromal-epithelial interactions in prostate cancer: Overexpression of PAGE4 in stromal cells inhibits the invasive ability of epithelial cells. J Cell Biochem 2020; 121:4406-4418. [PMID: 32003504 DOI: 10.1002/jcb.29664] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 01/09/2020] [Indexed: 12/17/2022]
Abstract
It is now widely recognized that carcinoma-associated fibroblasts which are believed to be myofibroblasts, promote the transformation of prostate epithelial cells to cancer cells, enhance their proliferation and invasiveness, and induce the acquisition of resistance to cancer therapy and immune evasiveness. Prostate-associated gene 4 (PAGE4) is an intrinsically disordered protein that is remarkably prostate-specific. PAGE4 is also a stress-response protein that functions as a transcriptional regulator and is upregulated in early-stage prostate cancer (PCa) and its precursor lesions. However, PAGE4 is downregulated in high-grade PCa and metastatic disease. Here, we show that PAGE4 is highly expressed in the stromal cells surrounding the cancer-adjacent "normal" glands and low-grade PCa lesions but not in lesions proximal to high-grade PCa. Overexpression of PAGE4 in a stromal cell line inhibits the migration and invasion of PCa epithelial cells in multiple coculture systems. PAGE4 overexpression also inhibits the downregulation of E-cadherin in PCa epithelial cells when cocultured with stromal cells. Furthermore, signaling via tumor necrosis factor-α and transforming growth factor-β pathways is decreased in the stromal cells overexpressing PAGE4 suggesting that PAGE4 appears to play a protective role against disease progression by perturbing interactions between epithelial cells and stromal cells in PCa. Taken together, these findings support previous observations that upregulation of PAGE4 in PCa correlates with a better prognosis and highlight PAGE4 as a novel therapeutic target for early-stage "low-risk" disease.
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Affiliation(s)
- Shui Fu
- Department of Urology, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, Liaoning, China
| | - Tao Liu
- Department of Urology, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Chengcheng Lv
- Department of Urology, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, Liaoning, China
| | - Cheng Fu
- Department of Urology, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, Liaoning, China
| | - Ruoheng Zeng
- Department of Neuroscience, College of Art and Science, New York University, New York, New York
| | - Yoshiyuki Kakehi
- Department of Urology, Kagawa University Faculty of Medicine, Kagawa, Kita-gun, Japan
| | - Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California
| | - Robert H Getzenberg
- Research Division, College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, Florida
| | - Yu Zeng
- Department of Urology, Liaoning Cancer Hospital and Institute, Cancer Hospital of China Medical University, Shenyang, Liaoning, China
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18
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Dephosphorylation of YB-1 is Required for Nuclear Localisation During G 2 Phase of the Cell Cycle. Cancers (Basel) 2020; 12:cancers12020315. [PMID: 32013098 PMCID: PMC7072210 DOI: 10.3390/cancers12020315] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/18/2020] [Accepted: 01/25/2020] [Indexed: 01/25/2023] Open
Abstract
Elevated levels of nuclear Y-box binding protein 1 (YB-1) are linked to poor prognosis in cancer. It has been proposed that entry into the nucleus requires specific proteasomal cleavage. However, evidence for cleavage is contradictory and high YB-1 levels are prognostic regardless of cellular location. Here, using confocal microscopy and mass spectrometry, we find no evidence of specific proteolytic cleavage. Doxorubicin treatment, and the resultant G2 arrest, leads to a significant increase in the number of cells where YB-1 is not found in the cytoplasm, suggesting that its cellular localisation is variable during the cell cycle. Live cell imaging reveals that the location of YB-1 is linked to progression through the cell cycle. Primarily perinuclear during G1 and S phases, YB-1 enters the nucleus as cells transition through late G2/M and exits at the completion of mitosis. Atomistic modelling and molecular dynamics simulations show that dephosphorylation of YB-1 at serine residues 102, 165 and 176 increases the accessibility of the nuclear localisation signal (NLS). We propose that this conformational change facilitates nuclear entry during late G2/M. Thus, the phosphorylation status of YB-1 determines its cellular location.
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19
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Guillien M, le Maire A, Mouhand A, Bernadó P, Bourguet W, Banères JL, Sibille N. IDPs and their complexes in GPCR and nuclear receptor signaling. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 174:105-155. [DOI: 10.1016/bs.pmbts.2020.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Kumar A, Narayanan V, Sekhar A. Characterizing Post-Translational Modifications and Their Effects on Protein Conformation Using NMR Spectroscopy. Biochemistry 2019; 59:57-73. [PMID: 31682116 DOI: 10.1021/acs.biochem.9b00827] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The diversity of the cellular proteome substantially exceeds the number of genes coded by the DNA of an organism because one or more residues in a majority of eukaryotic proteins are post-translationally modified (PTM) by the covalent conjugation of specific chemical groups. We now know that PTMs alter protein conformation and function in ways that are not entirely understood at the molecular level. NMR spectroscopy has been particularly successful as an analytical tool in elucidating the themes underlying the structural role of PTMs. In this Perspective, we focus on the NMR-based characterization of three abundant PTMs: phosphorylation, acetylation, and glycosylation. We detail NMR methods that have found success in detecting these modifications at a site-specific level. We also highlight NMR studies that have mapped the conformational changes ensuing from these PTMs as well as evaluated their relation to function. The NMR toolbox is expanding rapidly with experiments available to probe not only the average structure of biomolecules but also how this structure changes with time on time scales ranging from picoseconds to seconds. The atomic resolution insights into the biomolecular structure, dynamics, and mechanism accessible from NMR spectroscopy ensure that NMR will continue to be at the forefront of research in the structural biology of PTMs.
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Affiliation(s)
- Ajith Kumar
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560 012 , India
| | - Vaishali Narayanan
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560 012 , India
| | - Ashok Sekhar
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560 012 , India
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21
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Lohia R, Salari R, Brannigan G. Sequence specificity despite intrinsic disorder: How a disease-associated Val/Met polymorphism rearranges tertiary interactions in a long disordered protein. PLoS Comput Biol 2019; 15:e1007390. [PMID: 31626641 PMCID: PMC6821141 DOI: 10.1371/journal.pcbi.1007390] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/30/2019] [Accepted: 09/10/2019] [Indexed: 11/24/2022] Open
Abstract
The role of electrostatic interactions and mutations that change charge states in intrinsically disordered proteins (IDPs) is well-established, but many disease-associated mutations in IDPs are charge-neutral. The Val66Met single nucleotide polymorphism (SNP) in precursor brain-derived neurotrophic factor (BDNF) is one of the earliest SNPs to be associated with neuropsychiatric disorders, and the underlying molecular mechanism is unknown. Here we report on over 250 μs of fully-atomistic, explicit solvent, temperature replica-exchange molecular dynamics (MD) simulations of the 91 residue BDNF prodomain, for both the V66 and M66 sequence. The simulations were able to correctly reproduce the location of both local and non-local secondary structure changes due to the Val66Met mutation, when compared with NMR spectroscopy. We find that the change in local structure is mediated via entropic and sequence specific effects. We developed a hierarchical sequence-based framework for analysis and conceptualization, which first identifies “blobs” of 4-15 residues representing local globular regions or linkers. We use this framework within a novel test for enrichment of higher-order (tertiary) structure in disordered proteins; the size and shape of each blob is extracted from MD simulation of the real protein (RP), and used to parameterize a self-avoiding heterogenous polymer (SAHP). The SAHP version of the BDNF prodomain suggested a protein segmented into three regions, with a central long, highly disordered polyampholyte linker separating two globular regions. This effective segmentation was also observed in full simulations of the RP, but the Val66Met substitution significantly increased interactions across the linker, as well as the number of participating residues. The Val66Met substitution replaces β-bridging between V66 and V94 (on either side of the linker) with specific side-chain interactions between M66 and M95. The protein backbone in the vicinity of M95 is then free to form β-bridges with residues 31-41 near the N-terminus, which condenses the protein. A significant role for Met/Met interactions is consistent with previously-observed non-local effects of the Val66Met SNP, as well as established interactions between the Met66 sequence and a Met-rich receptor that initiates neuronal growth cone retraction. Intrinsically disordered proteins are proteins that have no well-defined structure in at least one functional form. Mutations in one amino acid may still affect their function significantly, especially in subtle ways with cumulative adverse effects on health. Here we report on molecular dynamics simulations of a protein that is critical for neuronal health throughout adulthood (brain-derived neurotrophic factor). We investigate the effects of a mutation carried by 30% of human population, which has been widely studied for its association with aging-related and stress-related disorders, reduced volume of the hippocampus, and variations in episodic memory. We identify a molecular mechanism in which the mutation may change the global conformations of the protein and its ability to bind to receptors.
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Affiliation(s)
- Ruchi Lohia
- Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey, United States of America
| | - Reza Salari
- Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey, United States of America
| | - Grace Brannigan
- Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey, United States of America
- Department of Physics, Rutgers University, Camden, New Jersey, United States of America
- * E-mail:
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22
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Sieradzan AK, Bogunia M, Mech P, Ganzynkowicz R, Giełdoń A, Liwo A, Makowski M. Introduction of Phosphorylated Residues into the UNRES Coarse-Grained Model: Toward Modeling of Signaling Processes. J Phys Chem B 2019; 123:5721-5729. [PMID: 31194908 DOI: 10.1021/acs.jpcb.9b03799] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Phosphorylated proteins take part in many signaling pathways and play a key role in homeostasis regulation. The all-atom force fields enable us to study the systems containing phosphorylated proteins, but they are limited to short time scales. In this paper, we report the extension of the physics-based coarse-grained UNRES force field to treat systems with phosphorylated amino-acid residues. To derive the respective potentials, appropriate physics-based analytical expressions were fitted to the potentials of mean force of systems modeling phosphorylated amino-acid residues computed in our previous work and implemented in UNRES. The extended UNRES performed well in ab initio simulations of two miniproteins containing phosphorylated residues, strongly suggesting that realistic large-scale simulations of processes involving phosphorylated proteins, especially signaling processes, are now possible.
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Affiliation(s)
- Adam K Sieradzan
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Małgorzata Bogunia
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Paulina Mech
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Robert Ganzynkowicz
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Artur Giełdoń
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Adam Liwo
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
| | - Mariusz Makowski
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
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23
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Kulkarni V, Kulkarni P. Intrinsically disordered proteins and phenotypic switching: Implications in cancer. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 166:63-84. [PMID: 31521237 DOI: 10.1016/bs.pmbts.2019.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is now well established that intrinsically disordered proteins (IDPs) that constitute a large part of the proteome across the three kingdoms, play critical roles in several biological processes including phenotypic switching. However, dysregulated expression of IDPs that engage in promiscuous interactions can lead to pathological states. In this chapter, using cancer as a paradigm, we discuss how IDP conformational dynamics and the resultant conformational noise can modulate phenotypic switching. Thus, contrary to the prevailing wisdom that phenotypic switching is highly deterministic (has a genetic underpinning) in cancer, emerging evidence suggests that non-genetic mechanisms, at least in part due to the conformational noise, may also be a confounding factor in phenotypic switching.
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Affiliation(s)
- Vivek Kulkarni
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, United States.
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24
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Recent Advances in Computational Protocols Addressing Intrinsically Disordered Proteins. Biomolecules 2019; 9:biom9040146. [PMID: 30979035 PMCID: PMC6523529 DOI: 10.3390/biom9040146] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 01/09/2023] Open
Abstract
Intrinsically disordered proteins (IDP) are abundant in the human genome and have recently emerged as major therapeutic targets for various diseases. Unlike traditional proteins that adopt a definitive structure, IDPs in free solution are disordered and exist as an ensemble of conformations. This enables the IDPs to signal through multiple signaling pathways and serve as scaffolds for multi-protein complexes. The challenge in studying IDPs experimentally stems from their disordered nature. Nuclear magnetic resonance (NMR), circular dichroism, small angle X-ray scattering, and single molecule Förster resonance energy transfer (FRET) can give the local structural information and overall dimension of IDPs, but seldom provide a unified picture of the whole protein. To understand the conformational dynamics of IDPs and how their structural ensembles recognize multiple binding partners and small molecule inhibitors, knowledge-based and physics-based sampling techniques are utilized in-silico, guided by experimental structural data. However, efficient sampling of the IDP conformational ensemble requires traversing the numerous degrees of freedom in the IDP energy landscape, as well as force-fields that accurately model the protein and solvent interactions. In this review, we have provided an overview of the current state of computational methods for studying IDP structure and dynamics and discussed the major challenges faced in this field.
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25
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Choi UB, Sanabria H, Smirnova T, Bowen ME, Weninger KR. Spontaneous Switching among Conformational Ensembles in Intrinsically Disordered Proteins. Biomolecules 2019; 9:biom9030114. [PMID: 30909517 PMCID: PMC6468417 DOI: 10.3390/biom9030114] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 01/08/2023] Open
Abstract
The common conception of intrinsically disordered proteins (IDPs) is that they stochastically sample all possible configurations driven by thermal fluctuations. This is certainly true for many IDPs, which behave as swollen random coils that can be described using polymer models developed for homopolymers. However, the variability in interaction energy between different amino acid sequences provides the possibility that some configurations may be strongly preferred while others are forbidden. In compact globular IDPs, core hydration and packing density can vary between segments of the polypeptide chain leading to complex conformational dynamics. Here, we describe a growing number of proteins that appear intrinsically disordered by biochemical and bioinformatic characterization but switch between restricted regions of conformational space. In some cases, spontaneous switching between conformational ensembles was directly observed, but few methods can identify when an IDP is acting as a restricted chain. Such switching between disparate corners of conformational space could bias ligand binding and regulate the volume of IDPs acting as structural or entropic elements. Thus, mapping the accessible energy landscape and capturing dynamics across a wide range of timescales are essential to recognize when an IDP is acting as such a switch.
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Affiliation(s)
- Ucheor B Choi
- Department of Molecular and Cellular Physiology, Department of Neurology and Neurological Sciences, Department of Structural Biology, Department of Photon Science, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA.
| | - Tatyana Smirnova
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA.
| | - Mark E Bowen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA.
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Role of Phosphorylation in the Modulation of the Glucocorticoid Receptor's Intrinsically Disordered Domain. Biomolecules 2019; 9:biom9030095. [PMID: 30862072 PMCID: PMC6468654 DOI: 10.3390/biom9030095] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/18/2019] [Accepted: 02/21/2019] [Indexed: 11/25/2022] Open
Abstract
Protein phosphorylation often switches cellular activity from one state to another, and this post-translational modification plays an important role in gene regulation by the nuclear hormone receptor superfamily, including the glucocorticoid receptor (GR). Cell signaling pathways that regulate phosphorylation of the GR are important determinants of GR actions, including lymphoid cell apoptosis, DNA binding, and interaction with coregulatory proteins. All major functionally important phosphorylation sites in the human GR are located in its N-terminal domain (NTD), which possesses a powerful transactivation domain, AF1. The GR NTD exists as an intrinsically disordered protein (IDP) and undergoes disorder-order transition for AF1’s efficient interaction with several coregulatory proteins and subsequent AF1-mediated GR activity. It has been reported that GR’s NTD/AF1 undergoes such disorder-order transition following site-specific phosphorylation. This review provides currently available information regarding the role of GR phosphorylation in its action and highlights the possible underlying mechanisms of action.
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Levy R, Gregory E, Borcherds W, Daughdrill G. p53 Phosphomimetics Preserve Transient Secondary Structure but Reduce Binding to Mdm2 and MdmX. Biomolecules 2019; 9:biom9030083. [PMID: 30832340 PMCID: PMC6468375 DOI: 10.3390/biom9030083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 02/07/2023] Open
Abstract
The disordered p53 transactivation domain (p53TAD) contains specific levels of transient helical secondary structure that are necessary for its binding to the negative regulators, mouse double minute 2 (Mdm2) and MdmX. The interactions of p53 with Mdm2 and MdmX are also modulated by posttranslational modifications (PTMs) of p53TAD including phosphorylation at S15, T18 and S20 that inhibits p53-Mdm2 binding. It is unclear whether the levels of transient secondary structure in p53TAD are changed by phosphorylation or other PTMs. We used phosphomimetic mutants to determine if adding a negative charge at positions 15 and 18 has any effect on the transient secondary structure of p53TAD and protein-protein binding. Using a combination of biophysical and structural methods, we investigated the effects of single and multisite phosphomimetics on the transient secondary structure of p53TAD and its interaction with Mdm2, MdmX, and the KIX domain. The phosphomimetics reduced Mdm2 and MdmX binding affinity by 3–5-fold, but resulted in minimal changes in transient secondary structure, suggesting that the destabilizing effect of phosphorylation on the p53TAD-Mdm2 interaction is primarily electrostatic. Phosphomimetics had no effect on the p53-KIX interaction, suggesting that increased binding of phosphorylated p53 to KIX may be influenced by decreased competition with its negative regulators.
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Affiliation(s)
- Robin Levy
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
- Center for Drug Discovery and Innovation, University of South Florida, Tampa, FL 33612, USA.
| | - Emily Gregory
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
- Center for Drug Discovery and Innovation, University of South Florida, Tampa, FL 33612, USA.
| | - Wade Borcherds
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
- Center for Drug Discovery and Innovation, University of South Florida, Tampa, FL 33612, USA.
| | - Gary Daughdrill
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
- Center for Drug Discovery and Innovation, University of South Florida, Tampa, FL 33612, USA.
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Fealey ME, Binder BP, Uversky VN, Hinderliter A, Thomas DD. Structural Impact of Phosphorylation and Dielectric Constant Variation on Synaptotagmin's IDR. Biophys J 2019; 114:550-561. [PMID: 29414700 DOI: 10.1016/j.bpj.2017.12.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/21/2017] [Accepted: 12/04/2017] [Indexed: 11/28/2022] Open
Abstract
We used time-resolved Förster resonance energy transfer, circular dichroism, and molecular dynamics simulation to investigate the structural dependence of synaptotagmin 1's intrinsically disordered region (IDR) on phosphorylation and dielectric constant. We found that a peptide corresponding to the full-length IDR sequence, a ∼60-residue strong polyampholyte, can sample structurally collapsed states in aqueous solution, consistent with its κ-predicted behavior, where κ is a sequence-dependent parameter that is used to predict IDR compaction. In implicit solvent simulations of this same sequence, lowering the dielectric constant to more closely mimic the environment near a lipid bilayer surface promoted further sampling of collapsed structures. We then examined the structural tendencies of central region residues of the IDR in isolation. We found that the exocytosis-modulating phosphorylation of Thr112 disrupts a local disorder-to-order transition induced by trifluoroethanol/water mixtures that decrease the solution dielectric constant and stabilize helical structure. Implicit solvent simulations on these same central region residues testing the impact of dielectric constant alone converge on a similar result, showing that helical structure is formed with higher probability at a reduced dielectric. In these helical conformers, lysine-aspartic acid salt bridges contribute to stabilization of transient secondary structure. In contrast, phosphorylation results in formation of salt bridges unsuitable for helix formation. Collectively, these results suggest a model in which phosphorylation and compaction of the IDR sequence regulate structural transitions that in turn modulate neuronal exocytosis.
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Affiliation(s)
- Michael E Fealey
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - Benjamin P Binder
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - Vladimir N Uversky
- Department of Molecular Medicine, University of South Florida, Tampa, Florida
| | - Anne Hinderliter
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota.
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Structural and Dynamical Order of a Disordered Protein: Molecular Insights into Conformational Switching of PAGE4 at the Systems Level. Biomolecules 2019; 9:biom9020077. [PMID: 30813315 PMCID: PMC6406393 DOI: 10.3390/biom9020077] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/10/2019] [Accepted: 02/10/2019] [Indexed: 01/10/2023] Open
Abstract
Folded proteins show a high degree of structural order and undergo (fairly constrained) collective motions related to their functions. On the other hand, intrinsically disordered proteins (IDPs), while lacking a well-defined three-dimensional structure, do exhibit some structural and dynamical ordering, but are less constrained in their motions than folded proteins. The larger structural plasticity of IDPs emphasizes the importance of entropically driven motions. Many IDPs undergo function-related disorder-to-order transitions driven by their interaction with specific binding partners. As experimental techniques become more sensitive and become better integrated with computational simulations, we are beginning to see how the modest structural ordering and large amplitude collective motions of IDPs endow them with an ability to mediate multiple interactions with different partners in the cell. To illustrate these points, here, we use Prostate-associated gene 4 (PAGE4), an IDP implicated in prostate cancer (PCa) as an example. We first review our previous efforts using molecular dynamics simulations based on atomistic AWSEM to study the conformational dynamics of PAGE4 and how its motions change in its different physiologically relevant phosphorylated forms. Our simulations quantitatively reproduced experimental observations and revealed how structural and dynamical ordering are encoded in the sequence of PAGE4 and can be modulated by different extents of phosphorylation by the kinases HIPK1 and CLK2. This ordering is reflected in changing populations of certain secondary structural elements as well as in the regularity of its collective motions. These ordered features are directly correlated with the functional interactions of WT-PAGE4, HIPK1-PAGE4 and CLK2-PAGE4 with the AP-1 signaling axis. These interactions give rise to repeated transitions between (high HIPK1-PAGE4, low CLK2-PAGE4) and (low HIPK1-PAGE4, high CLK2-PAGE4) cell phenotypes, which possess differing sensitivities to the standard PCa therapies, such as androgen deprivation therapy (ADT). We argue that, although the structural plasticity of an IDP is important in promoting promiscuous interactions, the modulation of the structural ordering is important for sculpting its interactions so as to rewire with agility biomolecular interaction networks with significant functional consequences.
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Lv C, Fu S, Dong Q, Yu Z, Zhang G, Kong C, Fu C, Zeng Y. PAGE4 promotes prostate cancer cells survive under oxidative stress through modulating MAPK/JNK/ERK pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:24. [PMID: 30658679 PMCID: PMC6339303 DOI: 10.1186/s13046-019-1032-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/09/2019] [Indexed: 02/08/2023]
Abstract
Background Prostate cancer (PCa) is one of the most common cancers in male worldwide. Oxidative stress has been recognized as one of the driving signals pathologically linked to PCa progression. Nevertheless, the association of oxidative stress with PCa progression remains unclear. Methods Western blot, q-RT-PCR and bioinformatics analyses were used to examine PAGE4 expression. Comet assay and Annexin V/ PI dual staining assay were performed to investigate DNA damage and cell death under oxidative stress. Mouse xenograft model of PCa cells was established to verify the role of PAGE4 in vivo. Transcriptomic analysis was performed to investigate the underlying mechanism for the function of PAGE4 under oxidative stress. Western blot assay was conducted to determine the status of MAPK pathway. Immunohistochemistry was used to identify protein expression of PAGE4 in tumor tissues. Results In this study, we found that PAGE4 expression was increased in PCa cells under oxidative stress condition. PAGE4 overexpression protected PCa cells from oxidative stress-inducing cell death by reducing DNA damage. PAGE4 overexpression promoted PCa cells growth in vivo. Mechanistically, PAGE4 promoted the survival of prostate cancer cells through regulating MAPK pathway which reflected in decreasing the phosphorylation of MAP2K4, JNK and c-JUN but increasing phosphorylation of ERK1/2. Conclusion Our findings indicate that PAGE4 protects PCa cells from DNA damage and apoptosis under oxidative stress by modulating MAPK signalling pathway. PAGE4 expression may serve as a prognostic biomarker for clinical applications. Electronic supplementary material The online version of this article (10.1186/s13046-019-1032-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chengcheng Lv
- Department of Urology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, 44 Xiaoheyan Road, Shenyang, 110042, Liaoning, China
| | - Shui Fu
- Department of Urology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, 44 Xiaoheyan Road, Shenyang, 110042, Liaoning, China
| | - Qingzhuo Dong
- Department of Urology, The First Hospital of China Medical University, 155 Nanjing North Road, Shenyang, 110001, Liaoning, China
| | - Zi Yu
- Department of Urology, The First Hospital of China Medical University, 155 Nanjing North Road, Shenyang, 110001, Liaoning, China
| | - Gejun Zhang
- Department of Urology, The First Hospital of China Medical University, 155 Nanjing North Road, Shenyang, 110001, Liaoning, China
| | - Chuize Kong
- Department of Urology, The First Hospital of China Medical University, 155 Nanjing North Road, Shenyang, 110001, Liaoning, China
| | - Cheng Fu
- Department of Urology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, 44 Xiaoheyan Road, Shenyang, 110042, Liaoning, China
| | - Yu Zeng
- Department of Urology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital and Institute, 44 Xiaoheyan Road, Shenyang, 110042, Liaoning, China.
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LeBlanc SJ, Kulkarni P, Weninger KR. Single Molecule FRET: A Powerful Tool to Study Intrinsically Disordered Proteins. Biomolecules 2018; 8:biom8040140. [PMID: 30413085 PMCID: PMC6315554 DOI: 10.3390/biom8040140] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 12/22/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are often modeled using ideas from polymer physics that suggest they smoothly explore all corners of configuration space. Experimental verification of this random, dynamic behavior is difficult as random fluctuations of IDPs cannot be synchronized across an ensemble. Single molecule fluorescence (or Förster) resonance energy transfer (smFRET) is one of the few approaches that are sensitive to transient populations of sub-states within molecular ensembles. In some implementations, smFRET has sufficient time resolution to resolve transitions in IDP behaviors. Here we present experimental issues to consider when applying smFRET to study IDP configuration. We illustrate the power of applying smFRET to IDPs by discussing two cases in the literature of protein systems for which smFRET has successfully reported phosphorylation-induced modification (but not elimination) of the disordered properties that have been connected to impacts on the related biological function. The examples we discuss, PAGE4 and a disordered segment of the GluN2B subunit of the NMDA receptor, illustrate the great potential of smFRET to inform how IDP function can be regulated by controlling the detailed ensemble of disordered states within biological networks.
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Affiliation(s)
- Sharonda J LeBlanc
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA.
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
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Kulkarni P, Uversky VN. Intrinsically Disordered Proteins: The Dark Horse of the Dark Proteome. Proteomics 2018; 18:e1800061. [DOI: 10.1002/pmic.201800061] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/07/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research; City of Hope National Medical Center; Duarte CA 91010 USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa FL 33612 USA
- Laboratory of New methods in Biology; Institute for Biological Instrumentation; Russian Academy of Sciences; Pushchino Moscow Region 142290 Russia
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Kulkarni P, Solomon TL, He Y, Chen Y, Bryan PN, Orban J. Structural metamorphism and polymorphism in proteins on the brink of thermodynamic stability. Protein Sci 2018; 27:1557-1567. [PMID: 30144197 PMCID: PMC6194243 DOI: 10.1002/pro.3458] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/11/2018] [Indexed: 12/13/2022]
Abstract
The classical view of the structure-function paradigm advanced by Anfinsen in the 1960s is that a protein's function is inextricably linked to its three-dimensional structure and is encrypted in its amino acid sequence. However, it is now known that a significant fraction of the proteome consists of intrinsically disordered proteins (IDPs). These proteins populate a polymorphic ensemble of conformations rather than a unique structure but are still capable of performing biological functions. At the boundary, between well-ordered and inherently disordered states are proteins that are on the brink of stability, either weakly stable ordered systems or disordered but on the verge of being stable. In such marginal states, even relatively minor changes can significantly alter the energy landscape, leading to large-scale conformational remodeling. Some proteins on the edge of stability are metamorphic, with the capacity to switch from one fold topology to another in response to an environmental trigger (e.g., pH, temperature/salt, redox). Many IDPs, on the other hand, are marginally unstable such that small perturbations (e.g., phosphorylation, ligands) tip the balance over to a range of ordered, partially ordered, or even more disordered states. In general, the structural transitions described by metamorphic fold switches and polymorphic IDPs possess a number of common features including low or diminished stability, large-scale conformational changes, critical disordered regions, latent or attenuated binding sites, and expansion of function. We suggest that these transitions are, therefore, conceptually and mechanistically analogous, representing adjacent regions in the continuum of order/disorder transitions.
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Affiliation(s)
- Prakash Kulkarni
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Tsega L. Solomon
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Yanan He
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Yihong Chen
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Philip N. Bryan
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - John Orban
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
- Department of Chemistry and BiochemistryUniversity of MarylandCollege ParkMaryland20742
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Prostate-Associated Gene 4 (PAGE4): Leveraging the Conformational Dynamics of a Dancing Protein Cloud as a Therapeutic Target. J Clin Med 2018; 7:jcm7060156. [PMID: 29914187 PMCID: PMC6025510 DOI: 10.3390/jcm7060156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 12/24/2022] Open
Abstract
Prostate cancer (PCa) is a leading cause of mortality and morbidity globally. While genomic alterations have been identified in PCa, in contrast to some other cancers, use of such information to personalize treatment is still in its infancy. Here, we discuss how PAGE4, a protein which appears to act both as an oncogenic factor as well as a metastasis suppressor, is a novel therapeutic target for PCa. Inhibiting PAGE4 may be a viable strategy for low-risk PCa where it is highly upregulated. Conversely, PAGE4 expression is downregulated in metastatic PCa and, therefore, reinstituting its sustained expression may be a promising option to subvert or attenuate androgen-resistant PCa. Thus, fine-tuning the levels of PAGE4 may represent a novel approach for personalized medicine in PCa.
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Lin X, Roy S, Jolly MK, Bocci F, Schafer NP, Tsai MY, Chen Y, He Y, Grishaev A, Weninger K, Orban J, Kulkarni P, Rangarajan G, Levine H, Onuchic JN. PAGE4 and Conformational Switching: Insights from Molecular Dynamics Simulations and Implications for Prostate Cancer. J Mol Biol 2018; 430:2422-2438. [PMID: 29758263 DOI: 10.1016/j.jmb.2018.05.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/13/2018] [Accepted: 05/07/2018] [Indexed: 11/15/2022]
Abstract
Prostate-associated gene 4 (PAGE4) is an intrinsically disordered protein implicated in prostate cancer. Thestress-response kinase homeodomain-interacting protein kinase 1 (HIPK1) phosphorylates two residues in PAGE4, serine 9 and threonine 51. Phosphorylation of these two residues facilitates the interaction of PAGE4 with activator protein-1 (AP-1) transcription factor complex to potentiate AP-1's activity. In contrast, hyperphosphorylation of PAGE4 by CDC-like kinase 2 (CLK2) attenuates this interaction with AP-1. Small-angleX-ray scattering and single-molecule fluorescence resonance energy transfer measurements have shown that PAGE4 expands upon hyperphosphorylation and that this expansion is localized to its N-terminal half. To understand the interactions underlying this structural transition, we performed molecular dynamics simulations using Atomistic AWSEM, a multi-scale molecular model that combines atomistic and coarse-grained simulation approaches. Our simulations show that electrostatic interactions drive transient formation of an N-terminal loop, the destabilization of which accounts for the dramatic change in size upon hyperphosphorylation. Phosphorylation also changes the preference of secondary structure formation of the PAGE4 ensemble, which leads to a transition between states that display different degrees of disorder. Finally, we construct a mechanism-based mathematical model that allows us to capture the interactions ofdifferent phosphoforms of PAGE4 with AP-1 and its downstream target, the androgen receptor (AR)-a key therapeutic target in prostate cancer. Our model predicts intracellular oscillatory dynamics of HIPK1-PAGE4, CLK2-PAGE4, and AR activity, indicating phenotypic heterogeneity in an isogenic cell population. Thus, conformational switching of PAGE4 may potentially affect the efficiency of therapeutically targeting AR activity.
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Affiliation(s)
- Xingcheng Lin
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States
| | - Susmita Roy
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States
| | - Mohit Kumar Jolly
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States
| | - Federico Bocci
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Chemistry, Rice University, Houston, TX 77005, United States
| | - Nicholas P Schafer
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Chemistry, Rice University, Houston, TX 77005, United States
| | - Min-Yeh Tsai
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Chemistry, Rice University, Houston, TX 77005, United States
| | - Yihong Chen
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, United States
| | - Yanan He
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, United States
| | - Alexander Grishaev
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, United States; National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, United States
| | - John Orban
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, United States; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, United States
| | - Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, United States; Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, United States
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India; Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Herbert Levine
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, United States; Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States; Department of Chemistry, Rice University, Houston, TX 77005, United States; Department of BioSciences, Rice University, Houston, TX 77005, United States.
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Newcombe EA, Ruff KM, Sethi A, Ormsby AR, Ramdzan YM, Fox A, Purcell AW, Gooley PR, Pappu RV, Hatters DM. Tadpole-like Conformations of Huntingtin Exon 1 Are Characterized by Conformational Heterogeneity that Persists regardless of Polyglutamine Length. J Mol Biol 2018; 430:1442-1458. [PMID: 29627459 DOI: 10.1016/j.jmb.2018.03.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/21/2018] [Accepted: 03/25/2018] [Indexed: 11/30/2022]
Abstract
Soluble huntingtin exon 1 (Httex1) with expanded polyglutamine (polyQ) engenders neurotoxicity in Huntington's disease. To uncover the physical basis of this toxicity, we performed structural studies of soluble Httex1 for wild-type and mutant polyQ lengths. Nuclear magnetic resonance experiments show evidence for conformational rigidity across the polyQ region. In contrast, hydrogen-deuterium exchange shows absence of backbone amide protection, suggesting negligible persistence of hydrogen bonds. The seemingly conflicting results are explained by all-atom simulations, which show that Httex1 adopts tadpole-like structures with a globular head encompassing the N-terminal amphipathic and polyQ regions and the tail encompassing the C-terminal proline-rich region. The surface area of the globular domain increases monotonically with polyQ length. This stimulates sharp increases in gain-of-function interactions in cells for expanded polyQ, and one of these interactions is with the stress-granule protein Fus. Our results highlight plausible connections between Httex1 structure and routes to neurotoxicity.
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Affiliation(s)
- Estella A Newcombe
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia
| | - Kiersten M Ruff
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St Louis, MO 63130, USA
| | - Ashish Sethi
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia
| | - Angelique R Ormsby
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia
| | - Yasmin M Ramdzan
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia
| | - Archa Fox
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA 6009, Australia
| | - Anthony W Purcell
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Paul R Gooley
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St Louis, MO 63130, USA.
| | - Danny M Hatters
- Department of Biochemistry and Molecular Biology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC 3010, Australia.
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Jolly MK, Kulkarni P, Weninger K, Orban J, Levine H. Phenotypic Plasticity, Bet-Hedging, and Androgen Independence in Prostate Cancer: Role of Non-Genetic Heterogeneity. Front Oncol 2018; 8:50. [PMID: 29560343 PMCID: PMC5845637 DOI: 10.3389/fonc.2018.00050] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 02/19/2018] [Indexed: 12/21/2022] Open
Abstract
It is well known that genetic mutations can drive drug resistance and lead to tumor relapse. Here, we focus on alternate mechanisms-those without mutations, such as phenotypic plasticity and stochastic cell-to-cell variability that can also evade drug attacks by giving rise to drug-tolerant persisters. The phenomenon of persistence has been well-studied in bacteria and has also recently garnered attention in cancer. We draw a parallel between bacterial persistence and resistance against androgen deprivation therapy in prostate cancer (PCa), the primary standard care for metastatic disease. We illustrate how phenotypic plasticity and consequent mutation-independent or non-genetic heterogeneity possibly driven by protein conformational dynamics can stochastically give rise to androgen independence in PCa, and suggest that dynamic phenotypic plasticity should be considered in devising therapeutic dosing strategies designed to treat and manage PCa.
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Affiliation(s)
- Mohit Kumar Jolly
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States
| | - Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, United States
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, United States
| | - John Orban
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, United States
- Department of Chemistry and Biochemistry, University of Maryland, College Park, College Park, United States
| | - Herbert Levine
- Center for Theoretical Biological Physics, Rice University, Houston, TX, United States
- Department of Bioengineering, Rice University, Houston, TX, United States
- Department of Physics and Astronomy, Rice University, Houston, TX, United States
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Site-specific phosphorylation regulates the structure and function of an intrinsically disordered domain of the glucocorticoid receptor. Sci Rep 2017; 7:15440. [PMID: 29133811 PMCID: PMC5684351 DOI: 10.1038/s41598-017-15549-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/30/2017] [Indexed: 11/23/2022] Open
Abstract
Intrinsically disordered (ID) regions of the transcription factor proteins have much larger frequency of phosphorylation sites than ordered regions, suggesting an important role in their regulatory capacity. Consistent with this phenomenon, most of the functionally known phosphorylation sites in the steroid receptor family of transcription factors are located in the ID N-terminal domain that contains a powerful activation function (AF1) region. In this study, we determined the structural and functional consequences of functionally known phosphorylation residues (Ser203, 211, and 226) located in the human glucocorticoid receptor’s (GR’s) ID AF1 domain. We report the relative importance of each phosphorylation site in inducing a functionally active ordered conformation in GR’s ID AF1 domain. Our data demonstrate a mechanism through which ID domain of the steroid receptors and other similar transcription factors may adopt a functionally active conformation under physiological conditions.
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Cancer/Testis Antigens: "Smart" Biomarkers for Diagnosis and Prognosis of Prostate and Other Cancers. Int J Mol Sci 2017; 18:ijms18040740. [PMID: 28362316 PMCID: PMC5412325 DOI: 10.3390/ijms18040740] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
A clinical dilemma in the management of prostate cancer (PCa) is to distinguish men with aggressive disease who need definitive treatment from men who may not require immediate intervention. Accurate prediction of disease behavior is critical because radical treatment is associated with high morbidity. Here, we highlight the cancer/testis antigens (CTAs) as potential PCa biomarkers. The CTAs are a group of proteins that are typically restricted to the testis in the normal adult but are aberrantly expressed in several types of cancers. Interestingly, >90% of CTAs are predicted to belong to the realm of intrinsically disordered proteins (IDPs), which do not have unique structures and exist as highly dynamic conformational ensembles, but are known to play important roles in several biological processes. Using prostate-associated gene 4 (PAGE4) as an example of a disordered CTA, we highlight how IDP conformational dynamics may regulate phenotypic heterogeneity in PCa cells, and how it may be exploited both as a potential biomarker as well as a promising therapeutic target in PCa. We also discuss how in addition to intrinsic disorder and post-translational modifications, structural and functional variability induced in the CTAs by alternate splicing represents an important feature that might have different roles in different cancers. Although it is clear that significant additional work needs to be done in the outlined direction, this novel concept emphasizing (multi)functionality as an important trait in selecting a biomarker underscoring the theranostic potential of CTAs that is latent in their structure (or, more appropriately, the lack thereof), and casts them as next generation or “smart” biomarker candidates.
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Mooney SM, Jolly MK, Levine H, Kulkarni P. Phenotypic plasticity in prostate cancer: role of intrinsically disordered proteins. Asian J Androl 2017; 18:704-10. [PMID: 27427552 PMCID: PMC5000791 DOI: 10.4103/1008-682x.183570] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A striking characteristic of cancer cells is their remarkable phenotypic plasticity, which is the ability to switch states or phenotypes in response to environmental fluctuations. Phenotypic changes such as a partial or complete epithelial to mesenchymal transition (EMT) that play important roles in their survival and proliferation, and development of resistance to therapeutic treatments, are widely believed to arise due to somatic mutations in the genome. However, there is a growing concern that such a deterministic view is not entirely consistent with multiple lines of evidence, which indicate that stochasticity may also play an important role in driving phenotypic plasticity. Here, we discuss how stochasticity in protein interaction networks (PINs) may play a key role in determining phenotypic plasticity in prostate cancer (PCa). Specifically, we point out that the key players driving transitions among different phenotypes (epithelial, mesenchymal, and hybrid epithelial/mesenchymal), including ZEB1, SNAI1, OVOL1, and OVOL2, are intrinsically disordered proteins (IDPs) and discuss how plasticity at the molecular level may contribute to stochasticity in phenotypic switching by rewiring PINs. We conclude by suggesting that targeting IDPs implicated in EMT in PCa may be a new strategy to gain additional insights and develop novel treatments for this disease, which is the most common form of cancer in adult men.
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Affiliation(s)
- Steven M Mooney
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Mohit Kumar Jolly
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005; Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Herbert Levine
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005; Department of Bioengineering, Rice University, Houston, TX 77005; Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, USA
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Kulkarni P. Intrinsically disordered proteins and prostate cancer: pouring new wine in an old bottle. Asian J Androl 2017; 18:659-61. [PMID: 27427556 PMCID: PMC5000785 DOI: 10.4103/1008-682x.184272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Prakash Kulkarni
- Protein Biophysics & Structural Biology Laboratory, Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
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Kulkarni P, Dunker AK, Weninger K, Orban J. Prostate-associated gene 4 (PAGE4), an intrinsically disordered cancer/testis antigen, is a novel therapeutic target for prostate cancer. Asian J Androl 2017; 18:695-703. [PMID: 27270343 PMCID: PMC5000790 DOI: 10.4103/1008-682x.181818] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Prostate-associated gene 4 (PAGE4) is a remarkably prostate-specific Cancer/Testis Antigen that is highly upregulated in the human fetal prostate and its diseased states but not in the adult normal gland. PAGE4 is an intrinsically disordered protein (IDP) that functions as a stress-response protein to suppress reactive oxygen species as well as prevent DNA damage. In addition, PAGE4 is also a transcriptional regulator that potentiates transactivation by the oncogene c-Jun. c-Jun forms the AP-1 complex by heterodimerizing with members of the Fos family and plays an important role in the development and pathology of the prostate gland, underscoring the importance of the PAGE4/c-Jun interaction. HIPK1, also a component of the stress-response pathway, phosphorylates PAGE4 at T51 which is critical for its transcriptional activity. Phosphorylation induces conformational and dynamic switching in the PAGE4 ensemble leading to a new cellular function. Finally, bioinformatics evidence suggests that the PAGE4 mRNA could be alternatively spliced resulting in four potential isoforms of the polypeptide alluding to the possibility of a range of conformational ensembles with latent functions. Considered together, the data suggest that PAGE4 may represent the first molecular link between stress and prostate cancer (PCa). Thus, pharmacologically targeting PAGE4 may be a novel opportunity for treating and managing patients with PCa, especially patients with low-risk disease.
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Affiliation(s)
- Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - A Keith Dunker
- Center for Computational Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, Indiana University School of Medicine and Informatics, Indianapolis, IN 46202, USA
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - John Orban
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
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Phosphorylation-induced conformational dynamics in an intrinsically disordered protein and potential role in phenotypic heterogeneity. Proc Natl Acad Sci U S A 2017; 114:E2644-E2653. [PMID: 28289210 DOI: 10.1073/pnas.1700082114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) that lack a unique 3D structure and comprise a large fraction of the human proteome play important roles in numerous cellular functions. Prostate-Associated Gene 4 (PAGE4) is an IDP that acts as a potentiator of the Activator Protein-1 (AP-1) transcription factor. Homeodomain-Interacting Protein Kinase 1 (HIPK1) phosphorylates PAGE4 at S9 and T51, but only T51 is critical for its activity. Here, we identify a second kinase, CDC-Like Kinase 2 (CLK2), which acts on PAGE4 and hyperphosphorylates it at multiple S/T residues, including S9 and T51. We demonstrate that HIPK1 is expressed in both androgen-dependent and androgen-independent prostate cancer (PCa) cells, whereas CLK2 and PAGE4 are expressed only in androgen-dependent cells. Cell-based studies indicate that PAGE4 interaction with the two kinases leads to opposing functions. HIPK1-phosphorylated PAGE4 (HIPK1-PAGE4) potentiates c-Jun, whereas CLK2-phosphorylated PAGE4 (CLK2-PAGE4) attenuates c-Jun activity. Consistent with the cellular data, biophysical measurements (small-angle X-ray scattering, single-molecule fluorescence resonance energy transfer, and NMR) indicate that HIPK1-PAGE4 exhibits a relatively compact conformational ensemble that binds AP-1, whereas CLK2-PAGE4 is more expanded and resembles a random coil with diminished affinity for AP-1. Taken together, the results suggest that the phosphorylation-induced conformational dynamics of PAGE4 may play a role in modulating changes between PCa cell phenotypes. A mathematical model based on our experimental data demonstrates how differential phosphorylation of PAGE4 can lead to transitions between androgen-dependent and androgen-independent phenotypes by altering the AP-1/androgen receptor regulatory circuit in PCa cells.
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Zeng J, Jiang F, Wu YD. Mechanism of Phosphorylation-Induced Folding of 4E-BP2 Revealed by Molecular Dynamics Simulations. J Chem Theory Comput 2016; 13:320-328. [PMID: 28068774 DOI: 10.1021/acs.jctc.6b00848] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Site-specific phosphorylation of an intrinsically disordered protein, eIF4E-binding protein isoform 2 (4E-BP2), can suppress its native function by folding it into a four-stranded β-sheet, but the mechanism of this phosphorylation-induced folding is unclear. In this work, we use all-atom molecular dynamics simulations to investigate both the folded and unfolded states of 4E-BP2 under different phosphorylation states of T37 and T46. The results show that the phosphorylated forms of both T37 and T46 play important roles in stabilizing the folded structure, especially for the β-turns and the sequestered binding motif. The phosphorylated residues not only guide the folding of the protein through several intermediate states but also affect the conformational distribution of the unfolded ensemble. Significantly, the phosphorylated residues can function as nucleation sites for the folding of the protein by forming certain local structures that are stabilized by hydrogen bonding involving the phosphate group. The region around phosphorylated T46 appears to fold before that around phosphorylated T37. These findings provide new insight into the intricate effects of protein phosphorylation.
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Affiliation(s)
- Juan Zeng
- Laboratory of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, China
| | - Fan Jiang
- Laboratory of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, China
| | - Yun-Dong Wu
- Laboratory of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, China.,College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
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Wall KP, Pagratis M, Armstrong G, Balsbaugh JL, Verbeke E, Pearson CG, Hough LE. Molecular Determinants of Tubulin's C-Terminal Tail Conformational Ensemble. ACS Chem Biol 2016; 11:2981-2990. [PMID: 27541566 DOI: 10.1021/acschembio.6b00507] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tubulin is important for a wide variety of cellular processes including cell division, ciliogenesis, and intracellular trafficking. To perform these diverse functions, tubulin is regulated by post-translational modifications (PTM), primarily at the C-terminal tails of both the α- and β-tubulin heterodimer subunits. The tubulin C-terminal tails are disordered segments that are predicted to extend from the ordered tubulin body and may regulate both intrinsic properties of microtubules and the binding of microtubule associated proteins (MAP). It is not understood how either interactions with the ordered tubulin body or PTM affect tubulin's C-terminal tails. To probe these questions, we developed a method to isotopically label tubulin for C-terminal tail structural studies by NMR. The conformational changes of the tubulin tails as a result of both proximity to the ordered tubulin body and modification by mono- and polyglycine PTM were determined. The C-terminal tails of the tubulin dimer are fully disordered and, in contrast with prior simulation predictions, exhibit a propensity for β-sheet conformations. The C-terminal tails display significant chemical shift differences as compared to isolated peptides of the same sequence, indicating that the tubulin C-terminal tails interact with the ordered tubulin body. Although mono- and polyglycylation affect the chemical shift of adjacent residues, the conformation of the C-terminal tail appears insensitive to the length of polyglycine chains. Our studies provide important insights into how the essential disordered domains of tubulin function.
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Affiliation(s)
| | - Maria Pagratis
- University of Colorado, Boulder, Colorado, United States
| | | | | | - Eric Verbeke
- University of Colorado, Boulder, Colorado, United States
| | - Chad G. Pearson
- University of Colorado, Anschutz Medical Campus, Colorado, United States
| | - Loren E. Hough
- University of Colorado, Boulder, Colorado, United States
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Mooney SM, Rajagopalan K, Rangarajan G, Kulkarni P. Cancer/testis antigens and obligate participation in multiple hallmarks of cancer: an update. Asian J Androl 2016; 18:711-2. [PMID: 26908068 PMCID: PMC5000792 DOI: 10.4103/1008-682x.174858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Cancer/Testis Antigens (CTAs) are a group of so-called tumor antigens that exhibit provocative expression patterns in most types of cancer. However, because most CTAs appear to be intrinsically disordered, they are recalcitrant to classical structural studies. Thus, the functions of most, if not all, CTAs have remained elusive and their potential as pharmacological targets in cancer has remained largely unexplored. In this viewpoint, we suggest that perhaps, an integrative approach applying dynamical systems theory and a system-level perspective rather a merely reductionist view, may shine new light on these enigmatic molecules.
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Affiliation(s)
- Steven M Mooney
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | | | - Govindan Rangarajan
- Department of Mathematics and Centre for Neuroscience, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, USA
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47
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Kulkarni P, Getzenberg RH. Disorder, Promiscuous Interactions, and Stochasticity Regulate State Switching in the Unstable Prostate. J Cell Biochem 2016; 117:2235-40. [PMID: 27152744 DOI: 10.1002/jcb.25578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 12/12/2022]
Abstract
A causal link between benign prostatic hyperplasia (BPH) and prostate cancer has long been suspected but not widely accepted. A new model is proposed that supports such a connection. In contrast to the prevailing wisdom, our model, that draws on dynamical systems theory, suggests that in response to stress, epithelial cells in the unstable gland can give rise to both types of diseases via a phenotypic switching mechanism. The central idea is that phenotypic switching is a stochastic process which exploits the plasticity of the epithelial cell. It is driven by 'noise' contributed by the conformational dynamics of proteins that are intrinsically disordered. In a system that is noisy when stressed, disorder promotes promiscuity, unmasks latent information, and rewires the network to cause phenotypic switching. Cells with newly acquired phenotypes can transcend the traditional zonal boundaries to give rise to BPH or prostate cancer depending on the microenvironment. Establishing causality between the two diseases may provide us with an opportunity to better understand their etiology and guide prevention and treatment strategies. J. Cell. Biochem. 117: 2235-2240, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Prakash Kulkarni
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland
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48
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Substitutions mimicking deimination and phosphorylation of 18.5-kDa myelin basic protein exert local structural effects that subtly influence its global folding. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1262-77. [DOI: 10.1016/j.bbamem.2016.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/30/2016] [Accepted: 02/17/2016] [Indexed: 11/20/2022]
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49
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Bah A, Forman-Kay JD. Modulation of Intrinsically Disordered Protein Function by Post-translational Modifications. J Biol Chem 2016; 291:6696-705. [PMID: 26851279 DOI: 10.1074/jbc.r115.695056] [Citation(s) in RCA: 344] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Post-translational modifications (PTMs) produce significant changes in the structural properties of intrinsically disordered proteins (IDPs) by affecting their energy landscapes. PTMs can induce a range of effects, from local stabilization or destabilization of transient secondary structure to global disorder-to-order transitions, potentially driving complete state changes between intrinsically disordered and folded states or dispersed monomeric and phase-separated states. Here, we discuss diverse biological processes that are dependent on PTM regulation of IDPs. We also present recent tools for generating homogenously modified IDPs for studies of PTM-mediated IDP regulatory mechanisms.
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Affiliation(s)
- Alaji Bah
- From the Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4 and the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Julie D Forman-Kay
- From the Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4 and the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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