1
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Cembran A, Fernandez-Funez P. Intrinsic determinants of prion protein neurotoxicity in Drosophila: from sequence to (dys)function. Front Mol Neurosci 2023; 16:1231079. [PMID: 37645703 PMCID: PMC10461008 DOI: 10.3389/fnmol.2023.1231079] [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: 06/23/2023] [Accepted: 08/02/2023] [Indexed: 08/31/2023] Open
Abstract
Prion diseases are fatal brain disorders characterized by deposition of insoluble isoforms of the prion protein (PrP). The normal and pathogenic structures of PrP are relatively well known after decades of studies. Yet our current understanding of the intrinsic determinants regulating PrP misfolding are largely missing. A 3D subdomain of PrP comprising the β2-α2 loop and helix 3 contains high sequence and structural variability among animals and has been proposed as a key domain regulating PrP misfolding. We combined in vivo work in Drosophila with molecular dynamics (MD) simulations, which provide additional insight to assess the impact of candidate substitutions in PrP from conformational dynamics. MD simulations revealed that in human PrP WT the β2-α2 loop explores multiple β-turn conformations, whereas the Y225A (rabbit PrP-like) substitution strongly favors a 310-turn conformation, a short right-handed helix. This shift in conformational diversity correlates with lower neurotoxicity in flies. We have identified additional conformational features and candidate amino acids regulating the high toxicity of human PrP and propose a new strategy for testing candidate modifiers first in MD simulations followed by functional experiments in flies. In this review we expand on these new results to provide additional insight into the structural and functional biology of PrP through the prism of the conformational dynamics of a 3D domain in the C-terminus. We propose that the conformational dynamics of this domain is a sensitive measure of the propensity of PrP to misfold and cause toxicity. This provides renewed opportunities to identify the intrinsic determinants of PrP misfolding through the contribution of key amino acids to different conformational states by MD simulations followed by experimental validation in transgenic flies.
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Affiliation(s)
- Alessandro Cembran
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, United States
| | - Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, United States
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2
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Serpa JJ, Popov KI, Petrotchenko EV, Dokholyan NV, Borchers CH. Structure of prion β-oligomers as determined by short-distance crosslinking constraint-guided discrete molecular dynamics simulations. Proteomics 2021; 21:e2000298. [PMID: 34482645 PMCID: PMC9285417 DOI: 10.1002/pmic.202000298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/10/2021] [Accepted: 08/27/2021] [Indexed: 11/08/2022]
Abstract
The conversion of the native monomeric cellular prion protein (PrPC ) into an aggregated pathological β-oligomeric form (PrPβ ) and an infectious form (PrPSc ) is the central element in the development of prion diseases. The structure of the aggregates and the molecular mechanisms of the conformational changes involved in the conversion are still unknown. We applied mass spectrometry combined with chemical crosslinking, hydrogen/deuterium exchange, limited proteolysis, and surface modification for the differential characterization of the native and the urea+acid-converted prion β-oligomer structures to obtain insights into the mechanisms of conversion and aggregation. For the determination of the structure of the monomer and the dimer unit of the β-oligomer, we applied a recently-developed approach for de novo protein structure determination which is based on the incorporation of zero-length and short-distance crosslinking data as intra- and inter-protein constraints in discrete molecular dynamics simulations (CL-DMD). Based on all of the structural-proteomics experimental data and the computationally predicted structures of the monomer units, we propose the potential mode of assembly of the β-oligomer. The proposed β-oligomer assembly provides a clue on the β-sheet nucleation site, and how template-based conversion of the native prion molecule occurs, growth of the prion aggregates, and maturation into fibrils may occur.
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Affiliation(s)
- Jason J Serpa
- University of Victoria -Genome British Columbia Proteomics Centre, Victoria, British Columbia, Canada
| | - Konstantin I Popov
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Evgeniy V Petrotchenko
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Nikolay V Dokholyan
- Department of Pharmacology, Department of Biochemistry & Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia.,Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
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3
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Myers R, Cembran A, Fernandez-Funez P. Insight From Animals Resistant to Prion Diseases: Deciphering the Genotype - Morphotype - Phenotype Code for the Prion Protein. Front Cell Neurosci 2020; 14:254. [PMID: 33013324 PMCID: PMC7461849 DOI: 10.3389/fncel.2020.00254] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/24/2020] [Indexed: 12/30/2022] Open
Abstract
Prion diseases are a group of neurodegenerative diseases endemic in humans and several ruminants caused by the misfolding of native prion protein (PrP) into pathological conformations. Experimental work and the mad-cow epidemic of the 1980s exposed a wide spectrum of animal susceptibility to prion diseases, including a few highly resistant animals: horses, rabbits, pigs, and dogs/canids. The variable susceptibility to disease offers a unique opportunity to uncover the mechanisms governing PrP misfolding, neurotoxicity, and transmission. Previous work indicates that PrP-intrinsic differences (sequence) are the main contributors to disease susceptibility. Several residues have been cited as critical for encoding PrP conformational stability in prion-resistant animals, including D/E159 in dog, S167 in horse, and S174 in rabbit and pig PrP (all according to human numbering). These amino acids alter PrP properties in a variety of assays, but we still do not clearly understand the structural correlates of PrP toxicity. Additional insight can be extracted from comparative structural studies, followed by molecular dynamics simulations of selected mutations, and testing in manipulable animal models. Our working hypothesis is that protective amino acids generate more compact and stable structures in a C-terminal subdomain of the PrP globular domain. We will explore this idea in this review and identify subdomains within the globular domain that may hold the key to unravel how conformational stability and disease susceptibility are encoded in PrP.
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Affiliation(s)
- Ryan Myers
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, United States
| | - Alessandro Cembran
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, United States
| | - Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, United States
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4
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Gharemirshamlu FR, Bamdad K, Naeimi S. Atomic insight into prion disorder: An intricate detail gained by 0.5 μs molecular dynamics simulation of preventive G127V and deleterious D178V mutation in prion protein. J Cell Biochem 2019; 120:14156-14164. [PMID: 30977169 DOI: 10.1002/jcb.28690] [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: 10/24/2018] [Revised: 02/22/2019] [Accepted: 02/28/2019] [Indexed: 11/10/2022]
Abstract
In this study we are looking into two contradicting mutations found in prion protein (PrP) viz G127V and D178V, that are reportedly protective and pathogenic, respectively. Despite significant advances in comprehension of the role of pathogenic mutations, the role of protective mutation in amyloid fold inhibition still lacks a substantial basis. To understand the structural basis of protective mutation, molecular dynamics simulation coupled with protein-protein docking and molecular mechanics/Poisson-Boltzmann surface area analysis was used to understand the instant structural variability brought about by these mutations alone and in combination on PrP and prion-prion complex. Atomic-scale investigations successfully revealed that the binding pattern of prion-prion varies differentially in protective and pathogenic mutations with secondary structure showing distinct contrasting patterns, which could supposedly be a critical factor for differential prion behavior in protective and pathogenic mutations. Considering the reported role of an amyloid fold in prion-prion binding, the contrasting pattern has given us a lead in comprehending the role of these mutations and has been used in this study to look for small molecules that can inhibit amyloid fold for prion-prion interaction in pathogenic mutant carrying PrP.
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Affiliation(s)
| | - Kourosh Bamdad
- Department of Biology, Payame Noor University, Tehrān, Iran
| | - Sirous Naeimi
- Department of Genetics, Islamic Azad University, Kāzerūn, Iran
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5
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Hannaoui S, Amidian S, Cheng YC, Duque Velásquez C, Dorosh L, Law S, Telling G, Stepanova M, McKenzie D, Wille H, Gilch S. Destabilizing polymorphism in cervid prion protein hydrophobic core determines prion conformation and conversion efficiency. PLoS Pathog 2017; 13:e1006553. [PMID: 28800624 PMCID: PMC5568445 DOI: 10.1371/journal.ppat.1006553] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/23/2017] [Accepted: 07/26/2017] [Indexed: 11/27/2022] Open
Abstract
Prion diseases are infectious neurodegenerative disorders of humans and animals caused by misfolded forms of the cellular prion protein PrPC. Prions cause disease by converting PrPC into aggregation-prone PrPSc. Chronic wasting disease (CWD) is the most contagious prion disease with substantial lateral transmission, affecting free-ranging and farmed cervids. Although the PrP primary structure is highly conserved among cervids, the disease phenotype can be modulated by species-specific polymorphisms in the prion protein gene. How the resulting amino-acid substitutions impact PrPC and PrPSc structure and propagation is poorly understood. We investigated the effects of the cervid 116A>G substitution, located in the most conserved PrP domain, on PrPC structure and conversion and on 116AG-prion conformation and infectivity. Molecular dynamics simulations revealed structural de-stabilization of 116G-PrP, which enhanced its in vitro conversion efficiency when used as recombinant PrP substrate in real-time quaking-induced conversion (RT-QuIC). We demonstrate that 116AG-prions are conformationally less stable, show lower activity as a seed in RT-QuIC and exhibit reduced infectivity in vitro and in vivo. Infectivity of 116AG-prions was significantly enhanced upon secondary passage in mice, yet conformational features were retained. These findings indicate that structurally de-stabilized PrPC is readily convertible by cervid prions of different genetic background and results in a prion conformation adaptable to cervid wild-type PrP. Conformation is an important criterion when assessing transmission barrier, and conformational variants can target a different host range. Therefore, a thorough analysis of CWD isolates and re-assessment of species-barriers is important in order to fully exclude a zoonotic potential of CWD. Chronic wasting disease (CWD) is a prion disease which affects wild and captive cervids. Prion diseases are infectious neurodegenerative disorders, and the causative agent consists of abnormally folded prion protein termed PrPSc. Prions replicate without genetic information, and their three-dimensional structure is thought to encode heritable information necessary to propagate using the cellular prion protein PrPC as a substrate for conversion. In this study, we use in vitro and in vivo techniques to analyze the effect of a polymorphism at codon 116 (A>G) of the white-tailed deer prion protein on CWD prion conformation, propagation and pathogenesis. We observed differences in conformation, infectivity and seeding activity in vitro between CWD prions isolated from white-tailed deer encoding wild-type (116AA) PrPC or 116AG-PrPC. In mouse bioassays conformational differences are retained, however, 116AG CWD prions resulted in significantly shortened incubation times upon passages. Molecular dynamics simulations suggest that the structure of 116G-PrPC is more flexible, which is supported by an improved convertibility in an in vitro conversion assay. Altogether these data indicate the importance of a variation in the most conserved PrP domain, and highlight the relationship between PrPC structural flexibility, prion conformation and conversion, and pathogenesis of prion disease in vivo.
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Affiliation(s)
- Samia Hannaoui
- Department of Ecosystem and Public Health, Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sara Amidian
- Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yo Ching Cheng
- Department of Ecosystem and Public Health, Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Camilo Duque Velásquez
- Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Lyudmyla Dorosh
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Sampson Law
- Department of Ecosystem and Public Health, Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Glenn Telling
- Prion Research Center, Colorado State University, Fort Collins, Colorado, United States of America
| | - Maria Stepanova
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Debbie McKenzie
- Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Holger Wille
- Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sabine Gilch
- Department of Ecosystem and Public Health, Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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6
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Understanding the Effect of Disease-Related Mutations on Human Prion Protein Structure: Insights From NMR Spectroscopy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:83-103. [DOI: 10.1016/bs.pmbts.2017.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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7
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Fonseca-Ornelas L, Zweckstetter M. The protonation state of histidine 111 regulates the aggregation of the evolutionary most conserved region of the human prion protein. Protein Sci 2016; 25:1563-7. [PMID: 27184108 DOI: 10.1002/pro.2947] [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: 04/05/2016] [Accepted: 05/13/2016] [Indexed: 12/18/2022]
Abstract
In a group of neurodegenerative diseases, collectively termed transmissible spongiform encephalopathies, the prion protein aggregates into β-sheet rich amyloid-like deposits. Because amyloid structure has been connected to different prion strains and cellular toxicity, it is important to obtain insight into the structural properties of prion fibrils. Using a combination of solution NMR spectroscopy, thioflavin-T fluorescence and electron microscopy we here show that within amyloid fibrils of a peptide containing residues 108-143 of the human prion protein [humPrP (108-143)]-the evolutionary most conserved part of the prion protein - residue H111 and S135 are in close spatial proximity and their interaction is critical for fibrillization. We further show that residues H111 and H140 share the same microenvironment in the unfolded, monomeric state of the peptide, but not in the fibrillar form. While protonation of H140 has little influence on fibrillization of humPrP (108-143), a positive charge at position 111 blocks the conformational change, which is necessary for amyloid formation of humPrP (108-143). Our study thus highlights the importance of protonation of histidine residues for protein aggregation and suggests point mutations to probe the structure of infectious prion particles.
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Affiliation(s)
- Luis Fonseca-Ornelas
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, 37077, Germany
| | - Markus Zweckstetter
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, 37077, Germany.,German Center for Neurodegenerative Diseases (DZNE), Von Siebold-Str. 3a, Göttingen, 37075, Germany.,Department of Neurology, University Medical Center Göttingen, University of Göttingen, Am Waldweg 33, Göttingen, 37073, Germany
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8
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Dalby A, Shamsir MS. Molecular Dynamics Simulations of the Temperature Induced Unfolding of Crambin Follow the Arrhenius Equation. F1000Res 2015; 4:589. [PMID: 26539292 PMCID: PMC4629273 DOI: 10.12688/f1000research.6831.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/23/2015] [Indexed: 12/02/2022] Open
Abstract
Molecular dynamics simulations have been used extensively to model the folding and unfolding of proteins. The rates of folding and unfolding should follow the Arrhenius equation over a limited range of temperatures. This study shows that molecular dynamic simulations of the unfolding of crambin between 500K and 560K do follow the Arrhenius equation. They also show that while there is a large amount of variation between the simulations the average values for the rate show a very high degree of correlation.
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Affiliation(s)
- Andrew Dalby
- Faculty of Science and Technology, University of Westminster, London, W1W 6UW, UK
| | - Mohd Shahir Shamsir
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Skudai, Johor, 81310, Malaysia
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9
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Minervini G, Quaglia F, Tosatto SCE. Insights into the proline hydroxylase (PHD) family, molecular evolution and its impact on human health. Biochimie 2015; 116:114-24. [PMID: 26187473 DOI: 10.1016/j.biochi.2015.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/12/2015] [Indexed: 12/18/2022]
Abstract
PHDs (proline hydroxylases) are a small protein family found in all organisms, considered the central regulator of the molecular hypoxia response due to PHDs being completely inactivated under low oxygen concentration. At physiological oxygen concentration, PHDs drive the degradation of the HIF-1α (hypoxia-inducible factor 1-α), which is responsible for upregulating the expression of genes involved in the cellular response to hypoxia. Hypoxia is a common feature of most tumors, in particular during metastasis development. Indeed, cancer reacts by activating pathways promoting new blood vessel formation and activating strategies aimed to improve survival. In this scenario, the PHD family regulates the activation of HIF-1α and cell-cycle regulation. Several PHD mutations were found in cancer patients, underlining their importance for human health. Here, we propose a Bayesian model able to predict the pathological effect of human PHD mutations and their correlation with cancer outcome. The model was developed through an integrative in silico approach, where data collected from the literature has been coupled with sequence evolution and structural analysis. The model was used to assess 135 human PHD variants. Finally, bioinformatics characterization was used to demonstrate how few amino acid changes are able to explain the functional specialization of PHD family members and their physiological role in human health.
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Affiliation(s)
- Giovanni Minervini
- Department of Biomedical Sciences, University of Padua, Viale G. Colombo 3, 35121, Padova, Italy
| | - Federica Quaglia
- Department of Biomedical Sciences, University of Padua, Viale G. Colombo 3, 35121, Padova, Italy
| | - Silvio C E Tosatto
- Department of Biomedical Sciences, University of Padua, Viale G. Colombo 3, 35121, Padova, Italy.
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10
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Wang B, Guo C, Lou Z, Xu B. Following the aggregation of human prion protein on Au(111) surface in real-time. Chem Commun (Camb) 2015; 51:2088-90. [DOI: 10.1039/c4cc09209k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of prion protein (PrP) aggregation on an Au(111) surface was determined by combining AFM real-time imaging with molecular dynamics and docking simulations.
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Affiliation(s)
- Bin Wang
- Single Molecule Study Laboratory
- Faculty of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Athens
- USA
| | - Cunlan Guo
- Single Molecule Study Laboratory
- Faculty of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Athens
- USA
| | - Zhichao Lou
- Single Molecule Study Laboratory
- Faculty of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Athens
- USA
| | - Bingqian Xu
- Single Molecule Study Laboratory
- Faculty of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Athens
- USA
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11
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Structural and dynamic properties of the human prion protein. Biophys J 2014; 106:1152-63. [PMID: 24606939 DOI: 10.1016/j.bpj.2013.12.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 12/11/2013] [Accepted: 12/26/2013] [Indexed: 11/23/2022] Open
Abstract
Prion diseases involve the conformational conversion of the cellular prion protein (PrP(C)) to its misfolded pathogenic form (PrP(Sc)). To better understand the structural mechanism of this conversion, we performed extensive all-atom, explicit-solvent molecular-dynamics simulations for three structures of the wild-type human PrP (huPrP) at different pH values and temperatures. Residue 129 is polymorphic, being either Met or Val. Two of the three structures have Met in position 129 and the other has Val. Lowering the pH or raising the temperature induced large conformational changes of the C-terminal globular domain and increased exposure of its hydrophobic core. In some simulations, HA and its preceding S1-HA loop underwent large displacements. The C-terminus of HB was unstable and sometimes partially unfolded. Two hydrophobic residues, Phe-198 and Met-134, frequently became exposed to solvent. These conformational changes became more dramatic at lower pH or higher temperature. Furthermore, Tyr-169 and the S2-HB loop, or the X-loop, were different in the starting structures but converged to common conformations in the simulations for the Met-129, but not the Val-129, protein. α-Strands and β-strands formed in the initially unstructured N-terminus. α-Strand propensity in the N-terminus was different between the Met-129 and Val129 proteins, but β-strand propensity was similar. This study reveals detailed structural and dynamic properties of huPrP, providing insight into the mechanism of the conversion of PrP(C) to PrP(Sc).
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12
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Scaini MC, Minervini G, Elefanti L, Ghiorzo P, Pastorino L, Tognazzo S, Agata S, Quaggio M, Zullato D, Bianchi-Scarrà G, Montagna M, D'Andrea E, Menin C, Tosatto SCE. CDKN2A unclassified variants in familial malignant melanoma: combining functional and computational approaches for their assessment. Hum Mutat 2014; 35:828-40. [PMID: 24659262 DOI: 10.1002/humu.22550] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 03/03/2014] [Indexed: 01/03/2023]
Abstract
CDKN2A codes for two oncosuppressors by alternative splicing of two first exons: p16INK4a and p14ARF. Germline mutations are found in about 40% of melanoma-prone families, and most of them are missense mutations mainly affecting p16INK4a. A growing number of p16INK4a variants of uncertain significance (VUS) are being identified but, unless their pathogenic role can be demonstrated, they cannot be used for identification of carriers at risk. Predicting the effect of these VUS by either a "standard" in silico approach, or functional tests alone, is rather difficult. Here, we report a protocol for the assessment of any p16INK4a VUS, which combines experimental and computational tools in an integrated approach. We analyzed p16INK4a VUS from melanoma patients as well as variants derived through permutation of conserved p16INK4a amino acids. Variants were expressed in a p16INK4a-null cell line (U2-OS) and tested for their ability to block proliferation. In parallel, these VUS underwent in silico prediction analysis and molecular dynamics simulations. Evaluation of in silico and functional data disclosed a high agreement for 15/16 missense mutations, suggesting that this approach could represent a pilot study for the definition of a protocol applicable to VUS in general, involved in other diseases, as well.
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Affiliation(s)
- Maria Chiara Scaini
- Immunology and Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
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13
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Ning L, Guo J, Bai Q, Jin N, Liu H, Yao X. Structural diversity and initial oligomerization of PrP106-126 studied by replica-exchange and conventional molecular dynamics simulations. PLoS One 2014; 9:e87266. [PMID: 24586266 PMCID: PMC3929351 DOI: 10.1371/journal.pone.0087266] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 12/24/2013] [Indexed: 12/15/2022] Open
Abstract
Prion diseases are marked by cerebral accumulation of the abnormal isoform of the prion protein. A fragment of prion protein composed of residues 106–126 (PrP106–126) exhibits similar properties to full length prion and plays a key role in the conformational conversion from cellular prion to its pathogenic pattern. Soluble oligomers of PrP106–126 have been proposed to be responsible for neurotoxicity. However, the monomeric conformational space and initial oligomerization of PrP106–126 are still obscure, which are very important for understanding the conformational conversion of PrP106–126. In this study, replica exchange molecular dynamics simulations were performed to investigate monomeric and dimeric states of PrP106–126 in implicit solvent. The structural diversity of PrP106–126 was observed and this peptide did not acquire stable structure. The dimeric PrP106–126 also displayed structural diversity and hydrophobic interaction drove the dimerization. To further study initial oligomerization of PrP106–126, 1 µs conventional molecular dynamics simulations of trimer and tetramer formation were carried out in implicit solvent. We have observed the spontaneous formation of several basic oligomers and stable oligomers with high β-sheet contents were sampled in the simulations of trimer and tetramer formation. The β-hairpin formed in hydrophobic tail of PrP106–126 with residues 118–120 in turn may stabilize these oligomers and seed the formation oligomers. This study can provide insight into the detailed information about the structure of PrP106–126 and the dynamics of aggregation of monomeric PrP106–126 into oligomers in atomic level.
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Affiliation(s)
- Lulu Ning
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Jingjing Guo
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Qifeng Bai
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | | | - Huanxiang Liu
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
- School of Pharmacy, Lanzhou University, Lanzhou, China
- * E-mail: (HL); (XY)
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
- State Key Lab for Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau, China
- * E-mail: (HL); (XY)
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14
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Torshin IY, Esipova NG, Tumanyan VG. Alternatingly twisted β-hairpins and nonglycine residues in the disallowed II′ region of the Ramachandran plot. J Biomol Struct Dyn 2013; 32:198-208. [DOI: 10.1080/07391102.2012.759451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Using simulations to provide the framework for experimental protein folding studies. Arch Biochem Biophys 2012; 531:128-35. [PMID: 23266569 DOI: 10.1016/j.abb.2012.12.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/10/2012] [Accepted: 12/14/2012] [Indexed: 12/27/2022]
Abstract
Molecular dynamics simulations are a powerful theoretical tool to model the protein folding process in atomistic details under realistic conditions. Combined with a number of experimental techniques, simulations provide a detailed picture of how a protein folds or unfolds in the presence of explicit solvent and other molecular species, such as cosolvents, osmolytes, cofactors, active binding partners or inert crowding agents. The denaturing effects of temperature, pressure and external mechanical forces can also be probed. Qualitative and quantitative agreement with experiment contributes to a comprehensive molecular picture of protein states along the folding/unfolding pathway. The variety of systems examined reveals key features of the protein folding process.
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Biljan I, Ilc G, Giachin G, Plavec J, Legname G. Structural Rearrangements at Physiological pH: Nuclear Magnetic Resonance Insights from the V210I Human Prion Protein Mutant. Biochemistry 2012; 51:7465-74. [DOI: 10.1021/bi3009856] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ivana Biljan
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000
Ljubljana, Slovenia
| | - Gregor Ilc
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000
Ljubljana, Slovenia
- EN→FIST Centre of Excellence, Dunajska 156, SI-1001 Ljubljana,
Slovenia
| | - Gabriele Giachin
- Laboratory of Prion
Biology, Department
of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste, Italy
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000
Ljubljana, Slovenia
- EN→FIST Centre of Excellence, Dunajska 156, SI-1001 Ljubljana,
Slovenia
- Faculty of Chemistry and Chemical
Technology, University of Ljubljana, Aškerčeva
cesta 5, SI-1000 Ljubljana, Slovenia
| | - Giuseppe Legname
- Laboratory of Prion
Biology, Department
of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste, Italy
- ELETTRA Laboratory, Sincrotrone Trieste S.C.p.A., I-34149 Basovizza, Trieste,
Italy
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17
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Structural basis for the protective effect of the human prion protein carrying the dominant-negative E219K polymorphism. Biochem J 2012; 446:243-51. [DOI: 10.1042/bj20111940] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The most common form of prion disease in humans is sCJD (sporadic Creutzfeldt–Jakob disease). The naturally occurring E219K polymorphism in the HuPrP (human prion protein) is considered to protect against sCJD. To gain insight into the structural basis of its protective influence we have determined the NMR structure of recombinant HuPrP (residues 90–231) carrying the E219K polymorphism. The structure of the HuPrP(E219K) protein consists of a disordered N-terminal tail (residues 90–124) and a well-structured C-terminal segment (residues 125–231) containing three α-helices and two short antiparallel β-strands. Comparison of NMR structures of the wild-type and HuPrPs with pathological mutations under identical experimental conditions revealed that, although the global architecture of the protein remains intact, replacement of Glu219 with a lysine residue introduces significant local structural changes. The structural findings of the present study suggest that the protective influence of the E219K polymorphism is due to the alteration of surface charge distribution, in addition to subtle structural rearrangements localized within the epitopes critical for prion conversion.
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Abstract
The conversion to a disease-associated conformer (PrP(Sc)) of the cellular prion protein (PrP(C)) is the central event in prion diseases. Wild-type PrPC converts to PrP(Sc) in the sporadic forms of the disorders through an unknown mechanism. These forms account for up to 85% of all human (Hu) occurrences; the infectious types contribute for less than 1%, while genetic incidence of the disease is about 15%. Familial Hu prion diseases are associated with about forty point mutations of the gene coding for the PrP denominated PRNP. Most of the variants associated with these mutations are located in the globular domain of the protein. In a recent work in collaboration with the German Research School for Simulation Science, in Jülich, Germany, we performed molecular dynamics simulations for each of these mutants to investigate their structure in aqueous solution. Structural analysis of the various point mutations present in the globular domain unveiled common folding traits that may allow to a better understanding of the early conformational changes leading to the formation of monomeric PrP(Sc). Recent experimental data support these findings, thus opening novel approaches to determine initial structural determinants of prion formation.
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Affiliation(s)
- Giuseppe Legname
- Laboratory of Prion Biology, Neurobiology Sector, Scuola Internazionale Superiore di Studi Avanzati-SISSA, Trieste, Italy.
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19
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Gendoo DMA, Harrison PM. The landscape of the prion protein's structural response to mutation revealed by principal component analysis of multiple NMR ensembles. PLoS Comput Biol 2012; 8:e1002646. [PMID: 22912570 PMCID: PMC3415401 DOI: 10.1371/journal.pcbi.1002646] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 07/04/2012] [Indexed: 11/18/2022] Open
Abstract
Prion Proteins (PrP) are among a small number of proteins for which large numbers of NMR ensembles have been resolved for sequence mutants and diverse species. Here, we perform a comprehensive principle components analysis (PCA) on the tertiary structures of PrP globular proteins to discern PrP subdomains that exhibit conformational change in response to point mutations and clade-specific evolutionary sequence mutation trends. This is to our knowledge the first such large-scale analysis of multiple NMR ensembles of protein structures, and the first study of its kind for PrPs. We conducted PCA on human (n = 11), mouse (n = 14), and wildtype (n = 21) sets of PrP globular structures, from which we identified five conformationally variable subdomains within PrP. PCA shows that different non-local patterns and rankings of variable subdomains arise for different pathogenic mutants. These subdomains may thus be key areas for initiating PrP conversion during disease. Furthermore, we have observed the conformational clustering of divergent TSE-non-susceptible species pairs; these non-phylogenetic clusterings indicate structural solutions towards TSE resistance that do not necessarily coincide with evolutionary divergence. We discuss the novelty of our approach and the importance of PrP subdomains in structural conversion during disease. Prion Proteins (PrP) cause a variety of incurable TSE diseases, and are among a small number of proteins for which large numbers of NMR ensembles have been resolved for sequence mutants and diverse species. Here, we perform a comprehensive PCA study to assess conformational variation and discern the landscape of the PrP structural response to sequence mutation. This is to our knowledge the first large-scale analysis of multiple NMR ensembles for a specific protein, and the first study to perform a multivariate PCA on the native globular structures of PrP. We conducted exhaustive PCA on three PrP subsets: human and mouse subsets that include structures of sequence mutants, and the set of wild-type PrP (16 PrP species). PCA shows that different non-local patterns of variable subdomains arise for different pathogenic mutants. These subdomains may thus be key areas for initiating PrP conversion during disease. Furthermore, we observed that some evolutionarily divergent species that are non-susceptible to TSEs have surprising structural similarities in their PrPs. We discuss the novelty of our approach with respect to prions, and the advantage of this analysis as a fast, reliable starting point to identify interesting domains that may warrant further experimental and computational analysis.
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Affiliation(s)
- Deena M. A. Gendoo
- Department of Biology, McGill University, Montreal, Quebec, Canada
- McGill Center for Bioinformatics, McGill University, Montreal, Quebec, Canada
| | - Paul M. Harrison
- Department of Biology, McGill University, Montreal, Quebec, Canada
- McGill Center for Bioinformatics, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Guo J, Ren H, Ning L, Liu H, Yao X. Exploring structural and thermodynamic stabilities of human prion protein pathogenic mutants D202N, E211Q and Q217R. J Struct Biol 2012; 178:225-32. [DOI: 10.1016/j.jsb.2012.03.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 03/23/2012] [Accepted: 03/26/2012] [Indexed: 12/18/2022]
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