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Pal S, Udgaonkar JB. Slow Misfolding of a Molten Globule form of a Mutant Prion Protein Variant into a β-rich Dimer. J Mol Biol 2024; 436:168736. [PMID: 39097185 DOI: 10.1016/j.jmb.2024.168736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/13/2024] [Accepted: 07/30/2024] [Indexed: 08/05/2024]
Abstract
Misfolding of the prion protein is linked to multiple neurodegenerative diseases. A better understanding of the process requires the identification and structural characterization of intermediate conformations via which misfolding proceeds. In this study, three conserved aromatic residues (Tyr168, Phe174, and Tyr217) located in the C-terminal domain of mouse PrP (wt moPrP) were mutated to Ala. The resultant mutant protein, 3A moPrP, is shown to adopt a molten globule (MG)-like native conformation. Hydrogen-deuterium exchange studies coupled with mass spectrometry revealed that for 3A moPrP, the free energy gap between the MG-like native conformation and misfolding-prone partially unfolded forms is reduced. Consequently, 3A moPrP misfolds in native conditions even in the absence of salt, unlike wt moPrP, which requires the addition of salt to misfold. 3A moPrP misfolds to a β-rich dimer in the absence of salt, which can rapidly form an oligomer upon the addition of salt. In the presence of salt, 3A moPrP misfolds to a β-rich oligomer about a thousand-fold faster than wt moPrP. Importantly, the misfolded structure of the dimer is similar to that of the salt-induced oligomer. Misfolding to oligomer seems to be induced at the level of the dimeric unit by monomer-monomer association, and the oligomer grows by accretion of misfolded dimeric units. Additionally, it is shown that the conserved aromatic residues collectively stabilize not only monomeric protein, but also the structural core of the β-rich oligomers. Finally, it is also shown that 3A moPrP misfolds much faster to amyloid-fibrils than does the wt protein.
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Affiliation(s)
- Suman Pal
- Indian Institute of Science Education and Research Pune, Pune 411008, India
| | - Jayant B Udgaonkar
- Indian Institute of Science Education and Research Pune, Pune 411008, India.
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Pal S, Udgaonkar JB. Mutations of evolutionarily conserved aromatic residues suggest that misfolding of the mouse prion protein may commence in multiple ways. J Neurochem 2023; 167:696-710. [PMID: 37941487 DOI: 10.1111/jnc.16007] [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: 08/17/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/10/2023]
Abstract
The misfolding of the mammalian prion protein from its α-helix rich cellular isoform to its β-sheet rich infectious isoform is associated with several neurodegenerative diseases. The determination of the structural mechanism by which misfolding commences, still remains an unsolved problem. In the current study, native-state hydrogen exchange coupled with mass spectrometry has revealed that the N state of the mouse prion protein (moPrP) at pH 4 is in dynamic equilibrium with multiple partially unfolded forms (PUFs) capable of initiating misfolding. Mutation of three evolutionarily conserved aromatic residues, Tyr168, Phe174, and Tyr217 present at the interface of the β2-α2 loop and the C-terminal end of α3 in the structured C-terminal domain of moPrP significantly destabilize the native state (N) of the protein. They also reduce the free energy differences between the N state and two PUFs identified as PUF1 and PUF2**. It is shown that PUF2** in which the β2-α2 loop and the C-terminal end of α3 are disordered, has the same stability as the previously identified PUF2*, but to have a very different structure. Misfolding can commence from both PUF1 and PUF2**, as it can from PUF2*. Hence, misfolding can commence and proceed in multiple ways from structurally distinct precursor conformations. The increased extents to which PUF1 and PUF2** are populated at equilibrium in the case of the mutant variants, greatly accelerate their misfolding. The results suggest that the three aromatic residues may have been evolutionarily selected to impede the misfolding of moPrP.
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Affiliation(s)
- Suman Pal
- Indian Institute of Science Education and Research Pune, Pune, India
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3
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Diociaiuti M, Bonanni R, Cariati I, Frank C, D’Arcangelo G. Amyloid Prefibrillar Oligomers: The Surprising Commonalities in Their Structure and Activity. Int J Mol Sci 2021; 22:ijms22126435. [PMID: 34208561 PMCID: PMC8235680 DOI: 10.3390/ijms22126435] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
It has been proposed that a “common core” of pathologic pathways exists for the large family of amyloid-associated neurodegenerations, including Alzheimer’s, Parkinson’s, type II diabetes and Creutzfeldt–Jacob’s Disease. Aggregates of the involved proteins, independently from their primary sequence, induced neuron membrane permeabilization able to trigger an abnormal Ca2+ influx leading to synaptotoxicity, resulting in reduced expression of synaptic proteins and impaired synaptic transmission. Emerging evidence is now focusing on low-molecular-weight prefibrillar oligomers (PFOs), which mimic bacterial pore-forming toxins that form well-ordered oligomeric membrane-spanning pores. At the same time, the neuron membrane composition and its chemical microenvironment seem to play a pivotal role. In fact, the brain of AD patients contains increased fractions of anionic lipids able to favor cationic influx. However, up to now the existence of a specific “common structure” of the toxic aggregate, and a “common mechanism” by which it induces neuronal damage, synaptotoxicity and impaired synaptic transmission, is still an open hypothesis. In this review, we gathered information concerning this hypothesis, focusing on the proteins linked to several amyloid diseases. We noted commonalities in their structure and membrane activity, and their ability to induce Ca2+ influx, neurotoxicity, synaptotoxicity and impaired synaptic transmission.
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Affiliation(s)
- Marco Diociaiuti
- Centro Nazionale Malattie Rare, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
- Correspondence:
| | - Roberto Bonanni
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy; (R.B.); (G.D.)
| | - Ida Cariati
- PhD in Medical-Surgical Biotechnologies and Translational Medicine, Department of Clinical Sciences and Translational Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Claudio Frank
- UniCamillus-Saint Camillus International University of Health Sciences, Via di Sant’Alessandro 8, 00131 Rome, Italy;
| | - Giovanna D’Arcangelo
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy; (R.B.); (G.D.)
- Centre of Space Bio-Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy
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Aerobic Exercise Induces Alternative Splicing of Neurexins in Frontal Cortex. J Funct Morphol Kinesiol 2021; 6:jfmk6020048. [PMID: 34072692 PMCID: PMC8261640 DOI: 10.3390/jfmk6020048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/02/2022] Open
Abstract
Aerobic exercise (AE) is known to produce beneficial effects on brain health by improving plasticity, connectivity, and cognitive functions, but the underlying molecular mechanisms are still limited. Neurexins (Nrxns) are a family of presynaptic cell adhesion molecules that are important in synapsis formation and maturation. In vertebrates, three-neurexin genes (NRXN1, NRXN2, and NRXN3) have been identified, each encoding for α and β neurexins, from two independent promoters. Moreover, each Nrxns gene (1-3) has several alternative exons and produces many splice variants that bind to a large variety of postsynaptic ligands, playing a role in trans-synaptic specification, strength, and plasticity. In this study, we investigated the impact of a continuous progressive (CP) AE program on alternative splicing (AS) of Nrxns on two brain regions: frontal cortex (FC) and hippocampus. We showed that exercise promoted Nrxns1-3 AS at splice site 4 (SS4) both in α and β isoforms, inducing a switch from exon-excluded isoforms (SS4-) to exon-included isoforms (SS4+) in FC but not in hippocampus. Additionally, we showed that the same AE program enhanced the expression level of other genes correlated with synaptic function and plasticity only in FC. Altogether, our findings demonstrated the positive effect of CP AE on FC in inducing molecular changes underlying synaptic plasticity and suggested that FC is possibly a more sensitive structure than hippocampus to show molecular changes.
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González-Sanmiguel J, Schuh CMAP, Muñoz-Montesino C, Contreras-Kallens P, Aguayo LG, Aguayo S. Complex Interaction between Resident Microbiota and Misfolded Proteins: Role in Neuroinflammation and Neurodegeneration. Cells 2020; 9:E2476. [PMID: 33203002 PMCID: PMC7697492 DOI: 10.3390/cells9112476] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/02/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Creutzfeldt-Jakob disease (CJD) are brain conditions affecting millions of people worldwide. These diseases are associated with the presence of amyloid-β (Aβ), alpha synuclein (α-Syn) and prion protein (PrP) depositions in the brain, respectively, which lead to synaptic disconnection and subsequent progressive neuronal death. Although considerable progress has been made in elucidating the pathogenesis of these diseases, the specific mechanisms of their origins remain largely unknown. A body of research suggests a potential association between host microbiota, neuroinflammation and dementia, either directly due to bacterial brain invasion because of barrier leakage and production of toxins and inflammation, or indirectly by modulating the immune response. In the present review, we focus on the emerging topics of neuroinflammation and the association between components of the human microbiota and the deposition of Aβ, α-Syn and PrP in the brain. Special focus is given to gut and oral bacteria and biofilms and to the potential mechanisms associating microbiome dysbiosis and toxin production with neurodegeneration. The roles of neuroinflammation, protein misfolding and cellular mediators in membrane damage and increased permeability are also discussed.
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Affiliation(s)
| | - Christina M. A. P. Schuh
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7710162, Chile; (C.M.A.P.S.); (P.C.-K.)
| | - Carola Muñoz-Montesino
- Department of Physiology, Universidad de Concepción, Concepción 4070386, Chile; (J.G.-S.); (C.M.-M.)
| | - Pamina Contreras-Kallens
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7710162, Chile; (C.M.A.P.S.); (P.C.-K.)
| | - Luis G. Aguayo
- Department of Physiology, Universidad de Concepción, Concepción 4070386, Chile; (J.G.-S.); (C.M.-M.)
- Program on Neuroscience, Psychiatry and Mental Health, Universidad de Concepción, Concepción 4070386, Chile
| | - Sebastian Aguayo
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
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Huin C, Cronier S, Guégan P, Béringue V, Rezaei H, Noinville S. Conformation-dependent membrane permeabilization by neurotoxic PrP oligomers: The role of the H2H3 oligomerization domain. Arch Biochem Biophys 2020; 692:108517. [PMID: 32738196 DOI: 10.1016/j.abb.2020.108517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/08/2020] [Accepted: 07/26/2020] [Indexed: 12/11/2022]
Abstract
The relationship between prion propagation and the generation of neurotoxic species and clinical onset remains unclear. Several converging lines of evidence suggest that interactions with lipids promote various precursors to form aggregation-prone states that are involved in amyloid fibrils. Here, we compared the cytotoxicities of different soluble isolated oligomeric constructs from murine full-length PrP and from the restricted helical H2H3 domain with their effects on lipid vesicles. The helical H2H3 domain is suggested to be the minimal region of PrP involved in the oligomerization process. The discrete PrP oligomers of both the full-length sequence and the H2H3 domain have de novo β-sheeted structure when interacting with the membrane. They were shown to permeabilize synthetic negatively charged vesicles in a dose-dependent manner. Restricting the polymerization domain of the full-length PrP to the H2H3 helices strongly diminished the ability of the corresponding oligomers to associate with the lipid vesicles. Furthermore, the membrane impairment mechanism occurs differently for the full-length PrP oligomers and the H2H3 helices, as shown by dye-release and black lipid membrane experiments. The membrane damage caused by the full-length PrP oligomers is correlated to their neuronal toxicity at submicromolar concentrations, as shown by cell culture assays. Although oligomers of synthetic H2H3 could compromise in vitro cell homeostasis, they followed a membrane-disruptive pattern that was different from the full-length oligomers, as revealed by the role of PrPC in cell viability assays.
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Affiliation(s)
- Cécile Huin
- Sorbonne Universités, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymères, 4 Place Jussieu, F-75005, Paris, France; University of Evry, F-91025, Evry, France
| | - Sabrina Cronier
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Philippe Guégan
- Sorbonne Universités, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymères, 4 Place Jussieu, F-75005, Paris, France
| | - Vincent Béringue
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Human Rezaei
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Sylvie Noinville
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR8233, MONARIS, Université Pierre et Marie Curie, Paris, France.
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7
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Combet S, Cousin F, Rezaei H, Noinville S. Membrane interaction of off-pathway prion oligomers and lipid-induced on-pathway intermediates during prion conversion: A clue for neurotoxicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:514-523. [PMID: 30529078 DOI: 10.1016/j.bbamem.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/21/2018] [Accepted: 12/04/2018] [Indexed: 12/31/2022]
Abstract
Soluble oligomers of prion proteins (PrP), produced during amyloid aggregation, have emerged as the primary neurotoxic species, instead of the fibrillar end-products, in transmissible spongiform encephalopathies. However, whether the membrane is among their direct targets, that mediate the downstream adverse effects, remains a question of debate. Recently, questions arise from the formation of membrane-active oligomeric species generated during the β-aggregation pathway, either in solution, or in lipid environment. In the present study, we characterized membrane interaction of off-pathway oligomers from recombinant prion protein generated along the amyloid aggregation and compared to lipid-induced intermediates produced during lipid-accelerated fibrillation. Using calcein-leakage assay, we show that the soluble prion oligomers are the most potent in producing leakage with negatively charged vesicles. Binding affinities, conformational states, mode of action of the different PrP assemblies were determined by thioflavin T binding-static light scattering experiments on DOPC/DOPS vesicles, as well as by FTIR-ATR spectroscopy and specular neutron reflectivity onto the corresponding supported lipid bilayers. Our results indicate that the off-pathway PrP oligomers interact with lipid membrane via a distinct mechanism, compared to the inserted lipid-induced intermediates. Thus, separate neurotoxic mechanisms could exist following the puzzling intermediates generated in the different cell compartments. These results not only reveal an important regulation of lipid membrane on PrP behavior but may also provide clues for designing stage-specific and prion-targeted therapy.
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Affiliation(s)
- Sophie Combet
- Laboratoire Léon-Brillouin, UMR 12 CEA-CNRS, Université Paris-Saclay, CEA-Saclay, F-91191 Gif-sur-Yvette CEDEX, France
| | - Fabrice Cousin
- Laboratoire Léon-Brillouin, UMR 12 CEA-CNRS, Université Paris-Saclay, CEA-Saclay, F-91191 Gif-sur-Yvette CEDEX, France
| | - Human Rezaei
- Laboratoire de Virologie et Immunologie Moléculaires, UR892, Institut National de la Recherche Agronomique (INRA), F-78352 Jouy-en-Josas, France
| | - Sylvie Noinville
- Laboratoire MONARIS, UMR 8233, Sorbonne Université, CNRS, F-75005 Paris, France.
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Singh J, Udgaonkar JB. Unraveling the Molecular Mechanism of pH-Induced Misfolding and Oligomerization of the Prion Protein. J Mol Biol 2016; 428:1345-1355. [PMID: 26854758 DOI: 10.1016/j.jmb.2016.01.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 12/31/2022]
Abstract
The misfolding of the prion protein (PrP) to aggregated forms is linked to several neurodegenerative diseases. Misfolded oligomeric forms of PrP are associated with neurotoxicity and/or infectivity, but the molecular mechanism by which they form is still poorly understood. A reduction in pH is known to be a key factor that triggers misfolded oligomer formation by PrP, but the residues whose protonation is linked with misfolding remain unidentified. The structural consequences of the protonation of these residues also remain to be determined. In the current study, amino acid residues whose protonation is critical for PrP misfolding and oligomerization have been identified using site-directed mutagenesis and misfolding/oligomerization assays. It is shown that the protonation of either H186 or D201, which mimics the effects of pathogenic mutations (H186R and D201N) at both residue sites, is critically linked to the stability, misfolding and oligomerization of PrP. Hydrogen-deuterium exchange studies coupled with mass spectrometry show that the protonation of either H186 or D201 leads to the same common structural change: increased structural dynamics in helix 1 and that in the loop between helix 1 and β-strand 2. It is shown that the protonation of either of these residues is sufficient for accelerating misfolded oligomer formation, most likely because the protonation of either residue causes the same structural perturbation. Hence, the increased structural dynamics in helix 1 and that in the loop between helix 1 and β-strand 2 appear to play an early critical role in acid-induced misfolding of PrP.
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Affiliation(s)
- Jogender Singh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.
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Ghio S, Kamp F, Cauchi R, Giese A, Vassallo N. Interaction of α-synuclein with biomembranes in Parkinson's disease--role of cardiolipin. Prog Lipid Res 2015; 61:73-82. [PMID: 26703192 DOI: 10.1016/j.plipres.2015.10.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/14/2015] [Accepted: 10/30/2015] [Indexed: 12/15/2022]
Abstract
One of the key molecular events underlying the pathogenesis of Parkinson's disease (PD) is the aberrant misfolding and aggregation of the α-synuclein (αS) protein into higher-order oligomers that play a key role in neuronal dysfunction and degeneration. A wealth of experimental data supports the hypothesis that the neurotoxicity of αS oligomers is intrinsically linked with their ability to interact with, and disrupt, biological membranes; especially those membranes having negatively-charged surfaces and/or lipid packing defects. Consequences of αS-lipid interaction include increased membrane tension, permeation by pore formation, membrane lysis and/or leakage due to the extraction of lipids from the bilayer. Moreover, we assert that the interaction of αS with a liquid-disordering phospholipid uniquely enriched in mitochondrial membranes, namely cardiolipin (1,3-diphosphatidyl-sn-glycerol, CL), helps target the αS oligomeric complexes intracellularly to mitochondria. Binding mediated by CL may thus represent an important pathomechanism by which cytosolic αS could physically associate with mitochondrial membranes and disrupt their integrity. Impaired mitochondrial function culminates in a cellular bioenergetic crisis and apoptotic death. To conclude, we advocate the accelerated discovery of new drugs targeting this pathway in order to restore mitochondrial function in PD.
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Affiliation(s)
- Stephanie Ghio
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Frits Kamp
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University & DZNE, 81377 Munich, Germany
| | - Ruben Cauchi
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Armin Giese
- Zentrum für Neuropathologie und Prionforschung, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Neville Vassallo
- Dept. of Physiology and Biochemistry, University of Malta, Msida, Malta.
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Singh J, Udgaonkar JB. Molecular Mechanism of the Misfolding and Oligomerization of the Prion Protein: Current Understanding and Its Implications. Biochemistry 2015; 54:4431-42. [PMID: 26171558 DOI: 10.1021/acs.biochem.5b00605] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Prion diseases, also known as transmissible spongiform encephalopathies, make up a group of fatal neurodegenerative disorders linked with the misfolding and aggregation of the prion protein (PrP). Although it is not yet understood how the misfolding of PrP induces neurodegeneration, it is widely accepted that the formation of misfolded prion protein (termed PrP(Sc)) is both the triggering event in the disease and the main component of the infectious agent responsible for disease transmission. Despite the clear involvement of PrP(Sc) in prion diseases, the exact composition of PrP(Sc) is not yet well-known. Recent studies show that misfolded oligomers of PrP could, however, be responsible for neurotoxicity and/or infectivity in the prion diseases. Hence, understanding the molecular mechanism of formation of the misfolded oligomers of PrP is critical for developing an understanding about the prion diseases and for developing anti-prion therapeutics. This review discusses recent advances in understanding the molecular mechanism of misfolded oligomer formation by PrP and its implications for the development of anti-prion therapeutics.
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Affiliation(s)
- Jogender Singh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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11
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Torrent J, Lange R, Rezaei H. The Volumetric Diversity of Misfolded Prion Protein Oligomers Revealed by Pressure Dissociation. J Biol Chem 2015; 290:20417-26. [PMID: 26126829 DOI: 10.1074/jbc.m115.661710] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Indexed: 11/06/2022] Open
Abstract
Protein oligomerization has been associated with a wide range of diseases. High pressure approaches offer a powerful tool for deciphering the underlying molecular mechanisms by revealing volume changes associated with the misfolding and assembly reactions. We applied high pressure to induce conformational changes in three distinct β-sheet-rich oligomers of the prion protein PrP, a protein characterized by a variety of infectious quaternary structures that can propagate stably and faithfully and cause diseases with specific phenotypic traits. We show that pressure induces dissociation of the oligomers and leads to a lower volume monomeric PrP state that refolds into the native conformation after pressure release. By measuring the different pressure and temperature sensitivity of the tested PrP oligomers, we demonstrate significantly different void volumes in their quaternary structure. In addition, by focusing on the kinetic and energetic behavior of the pressure-induced dissociation of one specific PrP oligomer, we reveal a large negative activation volume and an increase in both apparent activation enthalpy and entropy. This suggests a transition state ensemble that is less structured and significantly more hydrated than the oligomeric state. Finally, we found that site-specific fluorescent labeling allows monitoring of the transient population of a kinetic intermediate in the dissociation reaction. Our results indicate that defects in atomic packing may deserve consideration as a new factor that influences differences between PrP assemblies and that could be relevant also for explaining the origin of prion strains.
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Affiliation(s)
- Joan Torrent
- From the Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, Domaine de Vilvert, F-78350 Jouy-en-Josas, France and
| | - Reinhard Lange
- the Institut National de la Recherche Agronomique, UMR1208, Ingénierie des Agropolymères et Technologies Emergentes, Université Montpellier, F-34095 Montpellier, France
| | - Human Rezaei
- From the Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, Domaine de Vilvert, F-78350 Jouy-en-Josas, France and
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12
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Lhor M, Méthot M, Horchani H, Salesse C. Structure of the N-terminal segment of human retinol dehydrogenase 11 and its preferential lipid binding using model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:878-85. [DOI: 10.1016/j.bbamem.2014.12.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 11/25/2022]
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13
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Le Brun AP, Haigh CL, Drew SC, James M, Boland MP, Collins SJ. Neutron reflectometry studies define prion protein N-terminal peptide membrane binding. Biophys J 2014; 107:2313-24. [PMID: 25418300 PMCID: PMC4241452 DOI: 10.1016/j.bpj.2014.09.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 10/24/2022] Open
Abstract
The prion protein (PrP), widely recognized to misfold into the causative agent of the transmissible spongiform encephalopathies, has previously been shown to bind to lipid membranes with binding influenced by both membrane composition and pH. Aside from the misfolding events associated with prion pathogenesis, PrP can undergo various posttranslational modifications, including internal cleavage events. Alpha- and beta-cleavage of PrP produces two N-terminal fragments, N1 and N2, respectively, which interact specifically with negatively charged phospholipids at low pH. Our previous work probing N1 and N2 interactions with supported bilayers raised the possibility that the peptides could insert deeply with minimal disruption. In the current study we aimed to refine the binding parameters of these peptides with lipid bilayers. To this end, we used neutron reflectometry to define the structural details of this interaction in combination with quartz crystal microbalance interrogation. Neutron reflectometry confirmed that peptides equivalent to N1 and N2 insert into the interstitial space between the phospholipid headgroups but do not penetrate into the acyl tail region. In accord with our previous studies, interaction was stronger for the N1 fragment than for the N2, with more peptide bound per lipid. Neutron reflectometry analysis also detected lengthening of the lipid acyl tails, with a concurrent decrease in lipid area. This was most evident for the N1 peptide and suggests an induction of increased lipid order in the absence of phase transition. These observations stand in clear contrast to the findings of analogous studies of Ab and ?-synuclein and thereby support the possibility of a functional role for such N-terminal fragment-membrane interactions.
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Affiliation(s)
- Anton P Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia
| | - Cathryn L Haigh
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia
| | - Simon C Drew
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, 3010, Australia
| | - Michael James
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia; School of Chemistry, University of New South Wales, Kensington, New South Wales, 2052, Australia
| | - Martin P Boland
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia
| | - Steven J Collins
- Department of Pathology, Kenneth Myer Building, The University of Melbourne, Victoria, 3010, Australia.
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14
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Aidt FH, Hasholt LF, Christiansen M, Laursen H. Localization of A11-reactive oligomeric species in prion diseases. Histopathology 2013; 62:994-1001. [PMID: 23570304 DOI: 10.1111/his.12097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 01/13/2013] [Indexed: 12/16/2022]
Abstract
AIMS To investigate in prion diseases the in-situ localization of prion protein oligomers sharing a common epitope with amyloid oligomers involved in a range of neurodegenerative diseases. METHODS AND RESULTS We performed immunohistochemistry on sporadic Creutzfeldt-Jakob disease (sCJD) (n = 9) and hereditary Gerstmann-Sträussler-Scheinker disease (GSS) (n = 1) specimens with the anti-oligomer antibody A11 to determine the localization of reactive species. We found that A11 reactivity in the sCJD specimens was localized to the cerebral and cerebellar cortices both in spongiform and adjacent, non-spongiform areas, reminiscent of multicentric or diffuse plaques. In the GSS specimens, we found that staining was closely associated with kuru-like plaques, and that A11-reactive species colocalized with protease-resistant prion protein (Prp(Sc)). We also observed sporadic neuronal cytosolic staining in both types of specimen. CONCLUSIONS We confirm that intracellular and extracellular A11-reactive species are present in situ in sCJD cases and GSS, and that immunoreactivity for A11 and Prp(Sc) overlaps. We argue that the A11-reactive species are indeed composed of oligomeric Prp(Sc), and suggest that the toxic effects of Prp(Sc) oligomers could be related to the generic oligomeric conformation recognized by A11.
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Affiliation(s)
- Frederik H Aidt
- Section of Molecular Medicine, Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark.
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15
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Chakroun N, Fornili A, Prigent S, Kleinjung J, Dreiss CA, Rezaei H, Fraternali F. Decrypting Prion Protein Conversion into a β-Rich Conformer by Molecular Dynamics. J Chem Theory Comput 2013; 9:2455-2465. [PMID: 23700393 PMCID: PMC3656828 DOI: 10.1021/ct301118j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Indexed: 01/08/2023]
Abstract
Prion diseases are fatal neurodegenerative diseases characterized by the formation of β-rich oligomers and the accumulation of amyloid fibrillar deposits in the central nervous system. Understanding the conversion of the cellular prion protein into its β-rich polymeric conformers is fundamental to tackling the early stages of the development of prion diseases. In this paper, we have identified unfolding and refolding steps critical to the conversion into a β-rich conformer for different constructs of the ovine prion protein by molecular dynamics simulations. By combining our results with in vitro experiments, we show that the folded C-terminus of the ovine prion protein is able to recurrently undergo a drastic conformational change by displacement of the H1 helix, uncovering of the H2H3 domain, and formation of persistent β-sheets between H2 and H3 residues. The observed β-sheets refold toward the C-terminus exposing what we call a "bending region" comprising residues 204-214. This is strikingly coincident with the region harboring mutations determining the fate of the prion oligomerization process. The β-rich intermediate is used here for the construction of a putative model for the assembly into an oligomeric aggregate. The results presented here confirm the importance of the H2H3 domain for prion oligomer formation and therefore its potential use as molecular target in the design of novel prion inhibitors.
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Affiliation(s)
- Nesrine Chakroun
- Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London, SE1 9NH, United Kingdom ; Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, SE1 1UL, United Kingdom
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16
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Shaw BF, Schneider GF, Whitesides GM. Effect of surfactant hydrophobicity on the pathway for unfolding of ubiquitin. J Am Chem Soc 2012; 134:18739-45. [PMID: 23095057 DOI: 10.1021/ja3079863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This paper describes the interaction between ubiquitin (UBI) and three sodium n-alkyl sulfates (SC(n)S) that have the same charge (Z = -1) but different hydrophobicity (n = 10, 12, or 14). Increasing the hydrophobicity of the n-alkyl sulfate resulted in (i) an increase in the number of distinct intermediates (that is, complexes of UBI and surfactant) that form along the pathway of unfolding, (ii) a decrease in the minimum concentrations of surfactant at which intermediates begin to form (i.e., a more negative ΔG(binding) of surfactant for UBI), and (iii) an increase in the number of surfactant molecules bound to UBI in each intermediate or complex. These results demonstrate that small changes in the hydrophobicity of a surfactant can significantly alter the binding interactions with a folded or unfolded cytosolic protein.
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Affiliation(s)
- Bryan F Shaw
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
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17
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Prigent S, Rezaei H. PrP assemblies: spotting the responsible regions in prion propagation. Prion 2011; 5:69-75. [PMID: 21788728 DOI: 10.4161/pri.5.2.16383] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The "protein only" hypothesis states that the key phenomenon in prion pathogenesis is the conversion of the host protein (PrPC) into a b-sheet enriched polymeric and pathogenic conformer (PrPSc). However the region of PrP bearing the information for structural transfer is still controversial. In a recent report, we highlighted the role of the C terminal part i.e. the helixes H2 and H3, using mutation approaches on recombinant PrP. The H2H3 was shown to be the minimal region necessary to reproduce the oligomerisation pattern of the full-length protein. The oligomers produced from isolated H2H3 domain presented the same structural characteristics as the oligomers formed from the full-length PrP. Combining other groups' results, this paper further discusses the relative, direct or indirect role of different PrP regions in assembly. The H2H3 region represents the core of PrP oligomers and fibrils, whereas the N terminus could explain divergences among different aggregates. Finally this review evocates the possibility to separate the domain involved in prion information transference (i.e. prion replication) from the domain bearing the cytotoxicity properties.
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18
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Solomon IH, Huettner JE, Harris DA. Neurotoxic mutants of the prion protein induce spontaneous ionic currents in cultured cells. J Biol Chem 2010; 285:26719-26. [PMID: 20573963 DOI: 10.1074/jbc.m110.134619] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The mechanisms by which prions kill neurons and the role of the cellular prion protein in this process are enigmatic. Insight into these questions is provided by the neurodegenerative phenotypes of transgenic mice expressing prion protein (PrP) molecules with deletions of conserved amino acids in the central region. We report here that expression in transfected cells of the most toxic of these PrP deletion mutants (Delta105-125) induces large, spontaneous ionic currents that can be detected by patch-clamping techniques. These currents are produced by relatively non-selective, cation-permeable channels or pores in the cell membrane and can be silenced by overexpression of wild-type PrP, as well as by treatment with a sulfated glycosaminoglycan. Similar currents are induced by PrP molecules carrying several different point mutations in the central region that cause familial prion diseases in humans. The ionic currents described here are distinct from those produced in artificial lipid membranes by synthetic peptides derived from the PrP sequence because they are induced by membrane-anchored forms of PrP that are synthesized by cells and that are found in vivo. Our results indicate that the neurotoxicity of some mutant forms of PrP is attributable to enhanced ion channel activity and that wild-type PrP possesses a channel-silencing activity. Drugs that block PrP-associated channels or pores may therefore represent novel therapeutic agents for treatment of patients with prion diseases.
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Affiliation(s)
- Isaac H Solomon
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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