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Hong J, Garfolo R, Kabre S, Humml C, Velanac V, Roué C, Beck B, Jeanette H, Haslam S, Bach M, Arora S, Acheta J, Nave KA, Schwab MH, Jourd’heuil D, Poitelon Y, Belin S. PMP2 regulates myelin thickening and ATP production during remyelination. Glia 2024; 72:885-898. [PMID: 38311982 PMCID: PMC11027087 DOI: 10.1002/glia.24508] [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: 09/14/2023] [Revised: 12/22/2023] [Accepted: 01/16/2024] [Indexed: 02/06/2024]
Abstract
It is well established that axonal Neuregulin 1 type 3 (NRG1t3) regulates developmental myelin formation as well as EGR2-dependent gene activation and lipid synthesis. However, in peripheral neuropathy disease context, elevated axonal NRG1t3 improves remyelination and myelin sheath thickness without increasing Egr2 expression or activity, and without affecting the transcriptional activity of canonical myelination genes. Surprisingly, Pmp2, encoding for a myelin fatty acid binding protein, is the only gene whose expression increases in Schwann cells following overexpression of axonal NRG1t3. Here, we demonstrate PMP2 expression is directly regulated by NRG1t3 active form, following proteolytic cleavage. Then, using a transgenic mouse model overexpressing axonal NRG1t3 (NRG1t3OE) and knocked out for PMP2, we demonstrate that PMP2 is required for NRG1t3-mediated remyelination. We demonstrate that the sustained expression of Pmp2 in NRG1t3OE mice enhances the fatty acid uptake in sciatic nerve fibers and the mitochondrial ATP production in Schwann cells. In sum, our findings demonstrate that PMP2 is a direct downstream mediator of NRG1t3 and that the modulation of PMP2 downstream NRG1t3 activation has distinct effects on Schwann cell function during developmental myelination and remyelination.
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Affiliation(s)
- Jiayue Hong
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Rebekah Garfolo
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sejal Kabre
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Christian Humml
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Viktorija Velanac
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Clémence Roué
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Brianna Beck
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Haley Jeanette
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sarah Haslam
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Martin Bach
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Simar Arora
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Jenica Acheta
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Markus H. Schwab
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Paul Flechsig Institute of Neuropathology, University Hospital Leipzig, Leipzig, Germany
| | - David Jourd’heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York, USA
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sophie Belin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
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2
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Kanduc D. Molecular Mimicry between Meningococcal B Factor H-Binding Protein and Human Proteins. Glob Med Genet 2023; 10:311-314. [PMID: 38025196 PMCID: PMC10653992 DOI: 10.1055/s-0043-1776985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Abstract
This study calls attention on molecular mimicry and the consequent autoimmune cross reactivity as the molecular mechanism that can cause adverse events following meningococcal B vaccination and warns against active immunizations based on entire antigen.
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Affiliation(s)
- Darja Kanduc
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
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3
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Baga M, Rizzi S, Spagnoli C, Frattini D, Pisani F, Fusco C. A Novel Family with Demyelinating Charcot-Marie-Tooth Disease Caused by a Mutation in the PMP2 Gene: A Case Series of Nine Patients and a Brief Review of the Literature. CHILDREN (BASEL, SWITZERLAND) 2023; 10:children10050901. [PMID: 37238449 DOI: 10.3390/children10050901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/27/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023]
Abstract
INTRODUCTION Charcot-Marie-Tooth (CMT) is a group of inherited peripheral neuropathies characterized by wide genotypic and phenotypic variability. The onset is typically in childhood, and the most frequent clinical manifestations are predominantly distal muscle weakness, hypoesthesia, foot deformity (pes cavus) and areflexia. In the long term, complications such as muscle-tendon retractions, extremity deformities, muscle atrophy and pain may occur. Among CMT1, demyelinating and autosomal dominant forms, CMT1G is determined by mutations in the PMP2 myelin protein. RESULTS Starting from the index case, we performed a clinical, electrophysiological, neuroradiological and genetic evaluation of all family members for three generations; we identified p.Ile50del in PMP2 in all the nine affected members. They presented a typical clinical phenotype, with childhood-onset variable severity between generations and a chronic demyelinating sensory-motor polyneuropathy on the electrophysiologic examination; the progression was slow to very slow and predominant in the lower limbs. Our study reports a relatively large sample of patients, members of the same family, with CMT1G by PMP2, which is a rare form of demyelinating CMT, highlighting the genetic variability of the CMT family instead of the overlapping clinical phenotypes within demyelinating forms. To date, only supportive and preventive measures for the most severe complications are available; therefore, we believe that early diagnosis (clinical, electrophysiological and genetic) allows access to specialist follow-up and therapies, thereby improving the quality of life of patients.
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Affiliation(s)
- Margherita Baga
- Child Neurology and Psychiatry Unit, Department of Pediatrics, AUSL-IRCCS di Reggio Emilia, 42100 Reggio Emilia, Italy
| | - Susanna Rizzi
- Child Neurology and Psychiatry Unit, Department of Pediatrics, AUSL-IRCCS di Reggio Emilia, 42100 Reggio Emilia, Italy
| | - Carlotta Spagnoli
- Child Neurology and Psychiatry Unit, Department of Pediatrics, AUSL-IRCCS di Reggio Emilia, 42100 Reggio Emilia, Italy
| | - Daniele Frattini
- Child Neurology and Psychiatry Unit, Department of Pediatrics, AUSL-IRCCS di Reggio Emilia, 42100 Reggio Emilia, Italy
| | - Francesco Pisani
- Child Neuropsychiatric Unit, Human Neuroscience Department, Sapienza University of Rome, 00100 Rome, Italy
| | - Carlo Fusco
- Child Neurology and Psychiatry Unit, Department of Pediatrics, AUSL-IRCCS di Reggio Emilia, 42100 Reggio Emilia, Italy
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Multi-Omic Profiling, Structural Characterization, and Potent Inhibitor Screening of Evasion-Related Proteins of a Parasitic Nematode, Haemonchus contortus, Surviving Vaccine Treatment. Biomedicines 2023; 11:biomedicines11020411. [PMID: 36830947 PMCID: PMC9952990 DOI: 10.3390/biomedicines11020411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/15/2023] [Accepted: 01/27/2023] [Indexed: 02/01/2023] Open
Abstract
The emergence of drug-resistant parasitic nematodes in both humans and livestock calls for development of alternative and cost-effective control strategies. Barbervax® is the only registered vaccine for the economically important ruminant strongylid Haemonchus contortus. In this study, we compared the microbiome, genome-wide diversity, and transcriptome of H. contortus adult male populations that survived vaccination with an experimental vaccine after inoculation in sheep. Our genome-wide SNP analysis revealed 16 putative candidate vaccine evasion genes. However, we did not identify any evidence for changes in microbial community profiling based on the 16S rRNA gene sequencing results of the vaccine-surviving parasite populations. A total of fifty-eight genes were identified as significantly differentially expressed, with six genes being long non-coding (lnc) RNAs and none being putative candidate SNP-associated genes. The genes that highly upregulated in surviving parasites from vaccinated animals were associated with GO terms belonging to predominantly molecular functions and a few biological processes that may have facilitated evasion or potentially lessened the effect of the vaccine. These included five targets: astacin (ASTL), carbonate dehydratase (CA2), phospholipase A2 (PLA2), glutamine synthetase (GLUL), and fatty acid-binding protein (FABP3). Our tertiary structure predictions and modelling analyses were used to perform in silico searches of all published and commercially available inhibitor molecules or substrate analogs with potential broad-spectrum efficacy against nematodes of human and veterinary importance.
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Sutinen A, Nguyen GTT, Raasakka A, Muruganandam G, Loris R, Ylikallio E, Tyynismaa H, Bartesaghi L, Ruskamo S, Kursula P. Structural insights into Charcot-Marie-Tooth disease-linked mutations in human GDAP1. FEBS Open Bio 2022; 12:1306-1324. [PMID: 35509130 PMCID: PMC9249340 DOI: 10.1002/2211-5463.13422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/25/2022] [Accepted: 05/03/2022] [Indexed: 11/11/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral polyneuropathy in humans, and its different subtypes are linked to mutations in dozens of different genes. Mutations in ganglioside-induced differentiation-associated protein 1 (GDAP1) cause two types of CMT, demyelinating CMT4A and axonal CMT2K. The GDAP1-linked CMT genotypes are mainly missense point mutations. Despite clinical profiling and in vivo studies on the mutations, the etiology of GDAP1-linked CMT is poorly understood. Here, we describe the biochemical and structural properties of the Finnish founding CMT2K mutation H123R as well as CMT2K-linked R120W, both of which are autosomal dominant mutations. The disease variant proteins retain close to normal structure and solution behaviour, but both present a significant decrease in thermal stability. Using GDAP1 variant crystal structures, we identify a side chain interaction network between helices ⍺3, ⍺6, and ⍺7, which is affected by CMT mutations, as well as a hinge in the long helix ⍺6, which is linked to structural flexibility. Structural analysis of GDAP1 indicates that CMT may arise from disruption of specific intra- and intermolecular interaction networks, leading to alterations in GDAP1 structure and stability, and eventually, insufficient motor and sensory neuron function.
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Affiliation(s)
- Aleksi Sutinen
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Giang Thi Tuyet Nguyen
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Norway
| | - Gopinath Muruganandam
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Belgium
| | - Remy Loris
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Belgium
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland.,Clinical Neurosciences, Helsinki University Hospital, Neurology, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | | | - Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland.,Department of Biomedicine, University of Bergen, Norway
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6
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Piras IS, Huentelman MJ, Pinna F, Paribello P, Solmi M, Murru A, Carpiniello B, Manchia M, Zai CC. A review and meta-analysis of gene expression profiles in suicide. Eur Neuropsychopharmacol 2022; 56:39-49. [PMID: 34923210 DOI: 10.1016/j.euroneuro.2021.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 12/12/2022]
Abstract
Suicide claims over 800,000 deaths worldwide, making it a serious public health problem. The etiopathophysiology of suicide remains unclear and is highly complex, and postmortem gene expression studies can offer insights into the molecular biological mechanism underlying suicide. In the current study, we conducted a meta-analysis of postmortem brain gene expression in relation to suicide. We identified five gene expression datasets for postmortem orbitofrontal, prefrontal, or dorsolateral prefrontal cortical brain regions from the Gene Expression Omnibus repository. After quality control, the total sample size was 380 (141 suicide deaths and 239 deaths from other causes). We performed the analyses using two meta-analytic approaches. We further performed pathway and cell-set enrichment analyses. We found reduced expression of the KCNJ2 (Potassium Inwardly Rectifying Channel Subfamily J Member 2), A2M (Alpha-2-Macroglobulin), AGT (Angiotensinogen), PMP2 (Peripheral Myelin Protein 2), and VEZF1 (Vascular Endothelial Zinc Finger 1) genes (FDR p<0.05). Our findings support the involvement of astrocytes, stress response, immune system, and microglia in suicide. These findings will require further validation in additional large datasets.
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Affiliation(s)
- Ignazio S Piras
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, United States
| | - Matthew J Huentelman
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, United States
| | - Federica Pinna
- Section of Psychiatry, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; Unit of Clinical Psychiatry, University Hospital Agency of Cagliari, Cagliari, Italy
| | - Pasquale Paribello
- Section of Psychiatry, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; Unit of Clinical Psychiatry, University Hospital Agency of Cagliari, Cagliari, Italy
| | - Marco Solmi
- Department of Psychiatry, University of Ottawa, Ontario, Canada; Department of Mental Health, The Ottawa Hospital, Ontario, Canada; Ottawa Hospital Research Institute (OHRI) Clinical Epidemiology Program University of Ottawa Ottawa Ontario; Early Psychosis: Interventions and Clinical-detection (EPIC) Lab, Institute of Psychiatry, Psychology & Neuroscience, Department of Psychosis Studies, King's College London, London, United Kingdom
| | - Andrea Murru
- Bipolar and Depression Disorders Unit, Institute of Neuroscience, Hospital Clinic, IDIBAPS CIBERSAM, University of Barcelona, Barcelona, Catalonia, Spain
| | - Bernardo Carpiniello
- Section of Psychiatry, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; Unit of Clinical Psychiatry, University Hospital Agency of Cagliari, Cagliari, Italy
| | - Mirko Manchia
- Section of Psychiatry, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; Unit of Clinical Psychiatry, University Hospital Agency of Cagliari, Cagliari, Italy; Department of Pharmacology, Dalhousie University, Halifax, NS, Canada.
| | - Clement C Zai
- Neurogenetics Section, Molecular Brain Science, Tanenbaum Centre for Pharmacogenetics, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, Institute of Medical Science, Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA, United States
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7
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Chen J, Tieleman DP, Liang Q. Effects of Lid Domain Structural Changes on the Interactions between Peripheral Myelin Protein 2 and a Lipid Bilayer. J Phys Chem Lett 2022; 13:991-996. [PMID: 35060724 DOI: 10.1021/acs.jpclett.1c03961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Peripheral myelin protein 2 (P2) plays an important role in the stacking of the myelin membrane and lipid transport. Here we investigate the interactions between P2 and a model myelin membrane using molecular dynamics simulations, focusing on the effect of the L27D mutation and conformational changes in the α2-helix in the lid domain of P2. The L27D mutation weakens the binding of the lid domain of P2 on the membrane. The α2-helix is either folded or unfolded on the membrane. Compared with the α2-helix structure in water, the membrane stabilizes the structure of the α2-helix, whereas the unfolding of the α2-helix reduces the binding affinity of P2 on the membrane. These findings reveal the energetics of the mutant and the structural changes of P2 on the interactions between the protein and the lipid bilayer and help us to understand the microscopic mechanism of the formation of the myelin sheath structure and some neurological disorders.
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Affiliation(s)
- Jinyu Chen
- Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - D Peter Tieleman
- Centre for Molecular Simulations and Department of Biological Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Qing Liang
- Center for Statistical and Theoretical Condensed Matter Physics and Department of Physics, Zhejiang Normal University, Jinhua 321004, P. R. China
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8
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Pusterla J, Montich GG, Oliveira RG. Unraveling the etiology of myelin disorders: the P2 case in Charcot-Marie-Tooth disease. FEBS J 2021; 288:6677-6679. [PMID: 34327848 DOI: 10.1111/febs.16131] [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: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 11/30/2022]
Abstract
There are several examples of single mutations that lead to a well-defined disease through a well-known mechanism. In other cases, a collection of mutations of the same protein produces a pathology with different degrees of severity. The accompanying work by Uusitalo et al. studies several mutants of the fatty acid binding protein P2 of the peripheral nervous system myelin. They conserve the native tertiary structure but a remarkable difference in the capacity to interact with lipids. This could be a clue to unravel the complex way in which these mutations affect myelin structure and function in a variant of Charcot-Marie-Tooth disease. Comment on: https://doi.org/10.1111/febs.16079.
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Affiliation(s)
- Julio Pusterla
- Institute of Condensed Matter Physics, Department of Physics, TU Darmstadt, Germany
| | - Guillermo G Montich
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
| | - Rafael G Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
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9
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Kursula P. Small-angle X-ray scattering for the proteomics community: current overview and future potential. Expert Rev Proteomics 2021; 18:415-422. [PMID: 34210208 DOI: 10.1080/14789450.2021.1951242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Proteins are biological nanoparticles. For structural proteomics and hybrid structural biology, complementary methods are required that allow both high throughput and accurate automated data analysis. Small-angle X-ray scattering (SAXS) is a method for observing the size and shape of particles, such as proteins and complexes, in solution. SAXS data can be used to model both the structure, oligomeric state, conformational changes, and flexibility of biomolecular samples.Areas covered: The key principles of SAXS, its sample requirements, and its current and future applications for structural proteomics are briefly reviewed. Recent technical developments in SAXS experiments are discussed, and future potential of the method in structural proteomics is evaluated.Expert opinion: SAXS is a method suitable for several aspects of integrative structural proteomics, with current technical developments allowing for higher throughput and time-resolved studies, as well as the analysis of complex samples, such as membrane proteins. Increasing automation and streamlined data analysis are expected to equip SAXS for structure-based screening workflows. Originally, structural genomics had a heavy focus on folded, crystallizable proteins and complexes - SAXS is a method allowing an expansion of this focus to flexible and disordered systems.
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Affiliation(s)
- Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Biocenter Oulu & Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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10
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Uusitalo M, Klenow MB, Laulumaa S, Blakeley MP, Simonsen AC, Ruskamo S, Kursula P. Human myelin protein P2: from crystallography to time-lapse membrane imaging and neuropathy-associated variants. FEBS J 2021; 288:6716-6735. [PMID: 34138518 DOI: 10.1111/febs.16079] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/10/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Peripheral myelin protein 2 (P2) is a fatty acid-binding protein expressed in vertebrate peripheral nervous system myelin, as well as in human astrocytes. Suggested functions of P2 include membrane stacking and lipid transport. Mutations in the PMP2 gene, encoding P2, are associated with Charcot-Marie-Tooth disease (CMT). Recent studies have revealed three novel PMP2 mutations in CMT patients. To shed light on the structure and function of these P2 variants, we used X-ray and neutron crystallography, small-angle X-ray scattering, circular dichroism spectroscopy, computer simulations and lipid binding assays. The crystal and solution structures of the I50del, M114T and V115A variants of P2 showed minor differences to the wild-type protein, whereas their thermal stability was reduced. Vesicle aggregation assays revealed no change in membrane stacking characteristics, while the variants showed altered fatty acid binding. Time-lapse imaging of lipid bilayers indicated formation of double-membrane structures induced by P2, which could be related to its function in stacking of two myelin membrane surfaces in vivo. In order to better understand the links between structure, dynamics and function, the crystal structure of perdeuterated P2 was refined from room temperature data using neutrons and X-rays, and the results were compared to simulations and cryocooled crystal structures. Our data indicate similar properties for all known human P2 CMT variants; while crystal structures are nearly identical, thermal stability and function of CMT variants are impaired. Our data provide new insights into the structure-function relationships and dynamics of P2 in health and disease.
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Affiliation(s)
- Maiju Uusitalo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Martin Berg Klenow
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Saara Laulumaa
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland.,European Spallation Source, Lund, Sweden
| | | | - Adam Cohen Simonsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland.,Department of Biomedicine, University of Bergen, Norway
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11
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Molecular Regulation of Canalicular ABC Transporters. Int J Mol Sci 2021; 22:ijms22042113. [PMID: 33672718 PMCID: PMC7924332 DOI: 10.3390/ijms22042113] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 12/17/2022] Open
Abstract
The ATP-binding cassette (ABC) transporters expressed at the canalicular membrane of hepatocytes mediate the secretion of several compounds into the bile canaliculi and therefore play a key role in bile secretion. Among these transporters, ABCB11 secretes bile acids, ABCB4 translocates phosphatidylcholine and ABCG5/G8 is responsible for cholesterol secretion, while ABCB1 and ABCC2 transport a variety of drugs and other compounds. The dysfunction of these transporters leads to severe, rare, evolutionary biliary diseases. The development of new therapies for patients with these diseases requires a deep understanding of the biology of these transporters. In this review, we report the current knowledge regarding the regulation of canalicular ABC transporters' folding, trafficking, membrane stability and function, and we highlight the role of molecular partners in these regulating mechanisms.
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12
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Tsuge H. A myelin sheath protein forming its lattice. J Biol Chem 2020; 295:8706-8707. [PMID: 32591442 DOI: 10.1074/jbc.h120.014273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Indexed: 11/06/2022] Open
Abstract
The formation of a mature, multilayered myelin sheath requires the compaction of lipid bilayers, but the molecular mechanism by which these bilayers condense is an open question. In this issue, Ruskamo et al. find that peripheral myelin protein P2 forms an ordered three-dimensional lattice within model membranes using Escherichia coli polar lipid liposomes. These data will help to understand the assembly, function, and structure of the myelin sheath.
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Affiliation(s)
- Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.
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13
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Raasakka A, Kursula P. How Does Protein Zero Assemble Compact Myelin? Cells 2020; 9:E1832. [PMID: 32759708 PMCID: PMC7465998 DOI: 10.3390/cells9081832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/21/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Myelin protein zero (P0), a type I transmembrane protein, is the most abundant protein in peripheral nervous system (PNS) myelin-the lipid-rich, periodic structure of membrane pairs that concentrically encloses long axonal segments. Schwann cells, the myelinating glia of the PNS, express P0 throughout their development until the formation of mature myelin. In the intramyelinic compartment, the immunoglobulin-like domain of P0 bridges apposing membranes via homophilic adhesion, forming, as revealed by electron microscopy, the electron-dense, double "intraperiod line" that is split by a narrow, electron-lucent space corresponding to the extracellular space between membrane pairs. The C-terminal tail of P0 adheres apposing membranes together in the narrow cytoplasmic compartment of compact myelin, much like myelin basic protein (MBP). In mouse models, the absence of P0, unlike that of MBP or P2, severely disturbs myelination. Therefore, P0 is the executive molecule of PNS myelin maturation. How and when P0 is trafficked and modified to enable myelin compaction, and how mutations that give rise to incurable peripheral neuropathies alter the function of P0, are currently open questions. The potential mechanisms of P0 function in myelination are discussed, providing a foundation for the understanding of mature myelin development and how it derails in peripheral neuropathies.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
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14
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Extracellular proteostasis prevents aggregation during pathogenic attack. Nature 2020; 584:410-414. [PMID: 32641833 DOI: 10.1038/s41586-020-2461-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 04/16/2020] [Indexed: 12/26/2022]
Abstract
In metazoans, the secreted proteome participates in intercellular signalling and innate immunity, and builds the extracellular matrix scaffold around cells. Compared with the relatively constant intracellular environment, conditions for proteins in the extracellular space are harsher, and low concentrations of ATP prevent the activity of intracellular components of the protein quality-control machinery. Until now, only a few bona fide extracellular chaperones and proteases have been shown to limit the aggregation of extracellular proteins1-5. Here we performed a systematic analysis of the extracellular proteostasis network in Caenorhabditis elegans with an RNA interference screen that targets genes that encode the secreted proteome. We discovered 57 regulators of extracellular protein aggregation, including several proteins related to innate immunity. Because intracellular proteostasis is upregulated in response to pathogens6-9, we investigated whether pathogens also stimulate extracellular proteostasis. Using a pore-forming toxin to mimic a pathogenic attack, we found that C. elegans responded by increasing the expression of components of extracellular proteostasis and by limiting aggregation of extracellular proteins. The activation of extracellular proteostasis was dependent on stress-activated MAP kinase signalling. Notably, the overexpression of components of extracellular proteostasis delayed ageing and rendered worms resistant to intoxication. We propose that enhanced extracellular proteostasis contributes to systemic host defence by maintaining a functional secreted proteome and avoiding proteotoxicity.
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15
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Geroldi A, Prada V, Veneri F, Trevisan L, Origone P, Grandis M, Schenone A, Gemelli C, Lanteri P, Fossa P, Mandich P, Bellone E. Early onset demyelinating Charcot-Marie-Tooth disease caused by a novel in-frame isoleucine deletion in peripheral myelin protein 2. J Peripher Nerv Syst 2020; 25:102-106. [PMID: 32277537 DOI: 10.1111/jns.12375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022]
Abstract
Peripheral myelin protein 2 (PMP2) is a small protein located on the cytoplasmic side of compact myelin, involved in the lipids transport and in the myelination process. In the last years few families affected with demyelinating Charcot-Marie-Tooth neuropathy (CMT1), caused by PMP2 mutations, have been identified. In this study we describe the first case of a PMP2 in-frame deletion. PMP2 was analyzed by direct sequencing after exclusion of the most frequent CMT-associated genes by using a next generation sequencing (NGS) genes panel. Sanger sequencing was used for family's segregation analysis. Molecular modeling analysis was used to evaluate the mutation impact on the protein structure. A novel PMP2: p.I50del has been identified in a child with early onset CMT1 and in three affected family members. All family members show an early onset demyelinating neuropathy without other distinguish features. Molecular modeling analysis and in silico evaluations do not suggest a strong impact on the overall protein structure, but a most likely altered protein function. This study suggests the importance to add PMP2 in CMT NGS genes panels or, at most, to test it after major CMT1 genes exclusion, due to the lack of diagnostic-addressing additional features.
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Affiliation(s)
- Alessandro Geroldi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Medical Genetics, University of Genoa, Genoa, Italy
| | - Valeria Prada
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Neurology, University of Genoa, Genoa, Italy
| | - Francesca Veneri
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Neurology, University of Genoa, Genoa, Italy
| | - Lucia Trevisan
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Medical Genetics, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino-UOC Genetica Medica, Genoa, Italy
| | - Paola Origone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Medical Genetics, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino-UOC Genetica Medica, Genoa, Italy
| | - Marina Grandis
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Neurology, University of Genoa, Genoa, Italy.,IRCCS-Ospedale Policlinico San Martino-UOC Neurologia, Genoa, Italy
| | - Angelo Schenone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Neurology, University of Genoa, Genoa, Italy.,IRCCS-Ospedale Policlinico San Martino-UOC Neurologia, Genoa, Italy
| | - Chiara Gemelli
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Neurology, University of Genoa, Genoa, Italy
| | - Paola Lanteri
- IRCCS Giannina Gaslini-U.O. Neuropsichiatria Infantile, Genoa, Italy
| | - Paola Fossa
- Department of Pharmacy, School of Medical and Pharmaceutical Sciences, University of Genoa, Genoa, Italy
| | - Paola Mandich
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Medical Genetics, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino-UOC Genetica Medica, Genoa, Italy
| | - Emilia Bellone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health-Medical Genetics, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino-UOC Genetica Medica, Genoa, Italy
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16
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Ruskamo S, Krokengen OC, Kowal J, Nieminen T, Lehtimäki M, Raasakka A, Dandey VP, Vattulainen I, Stahlberg H, Kursula P. Cryo-EM, X-ray diffraction, and atomistic simulations reveal determinants for the formation of a supramolecular myelin-like proteolipid lattice. J Biol Chem 2020; 295:8692-8705. [PMID: 32265298 DOI: 10.1074/jbc.ra120.013087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/31/2020] [Indexed: 12/15/2022] Open
Abstract
Myelin protein P2 is a peripheral membrane protein of the fatty acid-binding protein family that functions in the formation and maintenance of the peripheral nerve myelin sheath. Several P2 gene mutations cause human Charcot-Marie-Tooth neuropathy, but the mature myelin sheath assembly mechanism is unclear. Here, cryo-EM of myelin-like proteolipid multilayers revealed an ordered three-dimensional (3D) lattice of P2 molecules between stacked lipid bilayers, visualizing supramolecular assembly at the myelin major dense line. The data disclosed that a single P2 layer is inserted between two bilayers in a tight intermembrane space of ∼3 nm, implying direct interactions between P2 and two membrane surfaces. X-ray diffraction from P2-stacked bicelle multilayers revealed lateral protein organization, and surface mutagenesis of P2 coupled with structure-function experiments revealed a role for both the portal region of P2 and its opposite face in membrane interactions. Atomistic molecular dynamics simulations of P2 on model membrane surfaces suggested that Arg-88 is critical for P2-membrane interactions, in addition to the helical lid domain. Negatively charged lipid headgroups stably anchored P2 on the myelin-like bilayer surface. Membrane binding may be accompanied by opening of the P2 β-barrel structure and ligand exchange with the apposing bilayer. Our results provide an unprecedented view into an ordered, multilayered biomolecular membrane system induced by the presence of a peripheral membrane protein from human myelin. This is an important step toward deciphering the 3D assembly of a mature myelin sheath at the molecular level.
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Affiliation(s)
- Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; Biocenter Oulu, University of Oulu, 90014 Oulu, Finland
| | - Oda C Krokengen
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway
| | - Julia Kowal
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4058 Basel, Switzerland
| | - Tuomo Nieminen
- Computational Physics Laboratory, Tampere University, 33014 Tampere, Finland
| | - Mari Lehtimäki
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway
| | - Venkata P Dandey
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4058 Basel, Switzerland
| | - Ilpo Vattulainen
- Computational Physics Laboratory, Tampere University, 33014 Tampere, Finland; Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, 4058 Basel, Switzerland
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; Biocenter Oulu, University of Oulu, 90014 Oulu, Finland; Department of Biomedicine, University of Bergen, 5020 Bergen, Norway.
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17
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Laulumaa S, Koza MM, Seydel T, Kursula P, Natali F. A Quasielastic Neutron Scattering Investigation on the Molecular Self-Dynamics of Human Myelin Protein P2. J Phys Chem B 2019; 123:8178-8185. [PMID: 31483648 DOI: 10.1021/acs.jpcb.9b05320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human myelin protein P2 is a membrane binding protein believed to maintain correct lipid composition and organization in peripheral nerve myelin. Its function is related to its ability to stack membranes, and this function can be enhanced by the P38G mutation, whereby the overall protein structure does not change but the molecular dynamics increase. Mutations in P2 are linked to human peripheral neuropathy. Here, the dynamics of wild-type P2 and the P38G variant were studied using quasielastic neutron scattering on time scales from 10 ps to 1 ns at 300 K. The results suggest that the mutant protein dynamics are increased on both the fastest and the slowest measured time scales, by increasing the dynamics amplitude and/or the portion of atoms participating in the movement.
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Affiliation(s)
- Saara Laulumaa
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu , University of Oulu , Oulu , Finland.,European Spallation Source , Lund , Sweden
| | | | | | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu , University of Oulu , Oulu , Finland.,Department of Biomedicine , University of Bergen , Bergen , Norway
| | - Francesca Natali
- Institut Laue-Langevin , Grenoble , France.,CNR-IOM, OGG , Grenoble , France
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18
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Laulumaa S, Kursula P. Sub-Atomic Resolution Crystal Structures Reveal Conserved Geometric Outliers at Functional Sites. Molecules 2019; 24:molecules24173044. [PMID: 31443388 PMCID: PMC6749445 DOI: 10.3390/molecules24173044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 01/28/2023] Open
Abstract
Myelin protein 2 (P2) is a peripheral membrane protein of the vertebrate nervous system myelin sheath, having possible roles in both lipid transport and 3D molecular organization of the multilayered myelin membrane. We extended our earlier crystallographic studies on human P2 and refined its crystal structure at an ultrahigh resolution of 0.72 Å in perdeuterated form and 0.86 Å in hydrogenated form. Characteristic differences in C–H…O hydrogen bond patterns were observed between extended β strands, kinked or ending strands, and helices. Often, side-chain C–H groups engage in hydrogen bonding with backbone carbonyl moieties. The data highlight several amino acid residues with unconventional conformations, including both bent aromatic rings and twisted guanidinium groups on arginine side chains, as well as non-planar peptide bonds. In two locations, such non-ideal conformations cluster, providing proof of local functional strain. Other ultrahigh-resolution protein structures similarly contain chemical groups, which break planarity rules. For example, in Src homology 3 (SH3) domains, a conserved bent aromatic residue is observed near the ligand binding site. Fatty acid binding protein (FABP) 3, belonging to the same family as P2, has several side chains and peptide bonds bent exactly as those in P2. We provide a high-resolution snapshot on non-ideal conformations of amino acid residues under local strain, possibly relevant to biological function. Geometric outliers observed in ultrahigh-resolution protein structures are real and likely relevant for ligand binding and conformational changes. Furthermore, the deuteration of protein and/or solvent are promising variables in protein crystal optimization.
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Affiliation(s)
- Saara Laulumaa
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, 90014 Oulu, Finland
- European Spallation Source, 22100 Lund, Sweden
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, 90014 Oulu, Finland.
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway.
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19
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Peripheral myelin protein 2 - a novel cluster of mutations causing Charcot-Marie-Tooth neuropathy. Orphanet J Rare Dis 2019; 14:197. [PMID: 31412900 PMCID: PMC6692960 DOI: 10.1186/s13023-019-1162-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/22/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Charcot-Marie-Tooth (CMT) disease is the most common inherited neuromuscular disorder characterized by wide clinical, genetic and pathomechanistic heterogeneity. Recently, the gene encoding peripheral myelin protein 2 (PMP2) was identified as a novel cause for CMT neuropathy with three mutations that structurally cluster together (p.Ile43Asn, p.Thr51Pro, p.Ile52Thr) reported in five families. RESULTS Using whole exome sequencing and cohort screening we identified two novel missense substitutions in PMP2 in Bulgarian (p.Met114Thr, c.341C > T) and German (p.Val115Ala, c.344 T > C) families. The mutations affect adjacent and highly conserved amino acid residues outside of the known mutation-rich region in the protein. Crystal structure analysis positions the affected residues within a cluster of highly conserved fatty acid coordinating residues implying their functional significance. The clinical, electrophysiological and imaging features in both families were consistent with a childhood onset polyneuropathy with variable patterns of demyelination, slow to very slow progression, and most severe involvement of the peroneal muscles. CONCLUSIONS We expand the genetic and phenotypic spectrum of PMP2-related peripheral neuropathy. Our findings reveal a second mutational cluster in the protein.
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20
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Neuropathy-related mutations alter the membrane binding properties of the human myelin protein P0 cytoplasmic tail. PLoS One 2019; 14:e0216833. [PMID: 31173589 PMCID: PMC6555526 DOI: 10.1371/journal.pone.0216833] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 04/29/2019] [Indexed: 01/19/2023] Open
Abstract
Schwann cells myelinate selected axons in the peripheral nervous system (PNS) and contribute to fast saltatory conduction via the formation of compact myelin, in which water is excluded from between tightly adhered lipid bilayers. Peripheral neuropathies, such as Charcot-Marie-Tooth disease (CMT) and Dejerine-Sottas syndrome (DSS), are incurable demyelinating conditions that result in pain, decrease in muscle mass, and functional impairment. Many Schwann cell proteins, which are directly involved in the stability of compact myelin or its development, are subject to mutations linked to these neuropathies. The most abundant PNS myelin protein is protein zero (P0); point mutations in this transmembrane protein cause CMT subtype 1B and DSS. P0 tethers apposing lipid bilayers together through its extracellular immunoglobulin-like domain. Additionally, P0 contains a cytoplasmic tail (P0ct), which is membrane-associated and contributes to the physical properties of the lipid membrane. Six CMT- and DSS-associated missense mutations have been reported in P0ct. We generated recombinant disease mutant variants of P0ct and characterized them using biophysical methods. Compared to wild-type P0ct, some mutants have negligible differences in function and folding, while others highlight functionally important amino acids within P0ct. For example, the D224Y variant of P0ct induced tight membrane multilayer stacking. Our results show a putative molecular basis for the hypermyelinating phenotype observed in patients with this particular mutation and provide overall information on the effects of disease-linked mutations in a flexible, membrane-binding protein segment. Using neutron reflectometry, we additionally show that P0ct embeds deep into a lipid bilayer, explaining the observed effects of P0ct on the physical properties of the membrane.
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21
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Raasakka A, Linxweiler H, Brophy PJ, Sherman DL, Kursula P. Direct Binding of the Flexible C-Terminal Segment of Periaxin to β4 Integrin Suggests a Molecular Basis for CMT4F. Front Mol Neurosci 2019; 12:84. [PMID: 31024253 PMCID: PMC6465933 DOI: 10.3389/fnmol.2019.00084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/19/2019] [Indexed: 11/13/2022] Open
Abstract
The process of myelination in the nervous system requires a coordinated formation of both transient and stable supramolecular complexes. Myelin-specific proteins play key roles in these assemblies, which may link membranes to each other or connect the myelinating cell cytoskeleton to the extracellular matrix. The myelin protein periaxin is known to play an important role in linking the Schwann cell cytoskeleton to the basal lamina through membrane receptors, such as the dystroglycan complex. Mutations that truncate periaxin from the C terminus cause demyelinating peripheral neuropathy, Charcot-Marie-Tooth (CMT) disease type 4F, indicating a function for the periaxin C-terminal region in myelination. We identified the cytoplasmic domain of β4 integrin as a specific high-affinity binding partner for periaxin. The C-terminal region of periaxin remains unfolded and flexible when bound to the third fibronectin type III domain of β4 integrin. Our data suggest that periaxin is able to link the Schwann cell cytoplasm to the basal lamina through a two-pronged interaction via different membrane protein complexes, which bind close to the N and C terminus of this elongated, flexible molecule.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Peter J. Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Diane L. Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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22
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Raasakka A, Ruskamo S, Kowal J, Han H, Baumann A, Myllykoski M, Fasano A, Rossano R, Riccio P, Bürck J, Ulrich AS, Stahlberg H, Kursula P. Molecular structure and function of myelin protein P0 in membrane stacking. Sci Rep 2019; 9:642. [PMID: 30679613 PMCID: PMC6345808 DOI: 10.1038/s41598-018-37009-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/30/2018] [Indexed: 12/22/2022] Open
Abstract
Compact myelin forms the basis of nerve insulation essential for higher vertebrates. Dozens of myelin membrane bilayers undergo tight stacking, and in the peripheral nervous system, this is partially enabled by myelin protein zero (P0). Consisting of an immunoglobulin (Ig)-like extracellular domain, a single transmembrane helix, and a cytoplasmic extension (P0ct), P0 harbours an important task in ensuring the integrity of compact myelin in the extracellular compartment, referred to as the intraperiod line. Several disease mutations resulting in peripheral neuropathies have been identified for P0, reflecting its physiological importance, but the arrangement of P0 within the myelin ultrastructure remains obscure. We performed a biophysical characterization of recombinant P0ct. P0ct contributes to the binding affinity between apposed cytoplasmic myelin membrane leaflets, which not only results in changes of the bilayer properties, but also potentially involves the arrangement of the Ig-like domains in a manner that stabilizes the intraperiod line. Transmission electron cryomicroscopy of native full-length P0 showed that P0 stacks lipid membranes by forming antiparallel dimers between the extracellular Ig-like domains. The zipper-like arrangement of the P0 extracellular domains between two membranes explains the double structure of the myelin intraperiod line. Our results contribute to the understanding of PNS myelin, the role of P0 therein, and the underlying molecular foundation of compact myelin stability in health and disease.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Julia Kowal
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Switzerland
| | - Huijong Han
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anne Baumann
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Matti Myllykoski
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anna Fasano
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Rocco Rossano
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Paolo Riccio
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Jochen Bürck
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway.
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland.
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23
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Punetha J, Mackay-Loder L, Harel T, Coban-Akdemir Z, Jhangiani SN, Gibbs RA, Lee I, Terespolsky D, Lupski JR, Posey JE. Identification of a pathogenic PMP2 variant in a multi-generational family with CMT type 1: Clinical gene panels versus genome-wide approaches to molecular diagnosis. Mol Genet Metab 2018; 125:302-304. [PMID: 30249361 PMCID: PMC6326168 DOI: 10.1016/j.ymgme.2018.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 01/07/2023]
Abstract
Charcot-Marie-Tooth (CMT) disease type 1 is an inherited peripheral neuropathy characterized by demyelination and reduced nerve conduction velocities. We present a multi-generational family with peripheral neuropathy in whom clinical CMT panel testing failed to conclude a molecular diagnosis. We found a PMP2 pathogenic variant c.155T > C, p.(Ile52Thr) that segregates with disease suggesting that PMP2 variants should be considered in patients with neuropathy and that it may be prudent to include in clinical CMT gene panels.
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Affiliation(s)
- Jaya Punetha
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Loren Mackay-Loder
- Department of Laboratory Medicine - Genetics Program, Trillium Health Partners, Mississauga, ON L5M 2N1, Canada
| | - Tamar Harel
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 9112001, Israel
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ian Lee
- Department of Laboratory Medicine - Genetics Program, Trillium Health Partners, Mississauga, ON L5M 2N1, Canada
| | - Deborah Terespolsky
- Department of Laboratory Medicine - Genetics Program, Trillium Health Partners, Mississauga, ON L5M 2N1, Canada
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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24
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Laulumaa S, Nieminen T, Raasakka A, Krokengen OC, Safaryan A, Hallin EI, Brysbaert G, Lensink MF, Ruskamo S, Vattulainen I, Kursula P. Structure and dynamics of a human myelin protein P2 portal region mutant indicate opening of the β barrel in fatty acid binding proteins. BMC STRUCTURAL BIOLOGY 2018; 18:8. [PMID: 29940944 PMCID: PMC6020228 DOI: 10.1186/s12900-018-0087-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/13/2018] [Indexed: 02/04/2023]
Abstract
Background Myelin is a multilayered proteolipid sheath wrapped around selected axons in the nervous system. Its constituent proteins play major roles in forming of the highly regular membrane structure. P2 is a myelin-specific protein of the fatty acid binding protein (FABP) superfamily, which is able to stack lipid bilayers together, and it is a target for mutations in the human inherited neuropathy Charcot-Marie-Tooth disease. A conserved residue that has been proposed to participate in membrane and fatty acid binding and conformational changes in FABPs is Phe57. This residue is thought to be a gatekeeper for the opening of the portal region upon ligand entry and egress. Results We performed a structural characterization of the F57A mutant of human P2. The mutant protein was crystallized in three crystal forms, all of which showed changes in the portal region and helix α2. In addition, the behaviour of the mutant protein upon lipid bilayer binding suggested more unfolding than previously observed for wild-type P2. On the other hand, membrane binding rendered F57A heat-stable, similarly to wild-type P2. Atomistic molecular dynamics simulations showed opening of the side of the discontinuous β barrel, giving important indications on the mechanism of portal region opening and ligand entry into FABPs. The results suggest a central role for Phe57 in regulating the opening of the portal region in human P2 and other FABPs, and the F57A mutation disturbs dynamic cross-correlation networks in the portal region of P2. Conclusions Overall, the F57A variant presents similar properties to the P2 patient mutations recently linked to Charcot-Marie-Tooth disease. Our results identify Phe57 as a residue regulating conformational changes that may accompany membrane surface binding and ligand exchange in P2 and other FABPs. Electronic supplementary material The online version of this article (10.1186/s12900-018-0087-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Saara Laulumaa
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.,European Spallation Source (ESS), Lund, Sweden
| | - Tuomo Nieminen
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Oda C Krokengen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Erik I Hallin
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Guillaume Brysbaert
- Unité de Glycobiologie Structurale et Fonctionnelle, University of Lille, CNRS UMR8576 UGSF, F-59000, Lille, France
| | - Marc F Lensink
- Unité de Glycobiologie Structurale et Fonctionnelle, University of Lille, CNRS UMR8576 UGSF, F-59000, Lille, France
| | - Salla Ruskamo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, Tampere, Finland.,Department of Physics, University of Helsinki, Helsinki, Finland
| | - Petri Kursula
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland. .,Department of Biomedicine, University of Bergen, Bergen, Norway.
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