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Nieto-Estevez V, Varma P, Mirsadeghi S, Caballero J, Gamero-Alameda S, Hosseini A, Silvosa MJ, Thodeson DM, Lybrand ZR, Giugliano M, Navara C, Hsieh J. Dual effects of ARX poly-alanine mutations in human cortical and interneuron development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577271. [PMID: 38328230 PMCID: PMC10849640 DOI: 10.1101/2024.01.25.577271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Infantile spasms, with an incidence of 1.6 to 4.5 per 10,000 live births, are a relentless and devastating childhood epilepsy marked by severe seizures but also leads to lifelong intellectual disability. Alarmingly, up to 5% of males with this condition carry a mutation in the Aristaless-related homeobox ( ARX ) gene. Our current lack of human-specific models for developmental epilepsy, coupled with discrepancies between animal studies and human data, underscores the gap in knowledge and urgent need for innovative human models, organoids being one of the best available. Here, we used human neural organoid models, cortical organoids (CO) and ganglionic eminences organoids (GEO) which mimic cortical and interneuron development respectively, to study the consequences of PAE mutations, one of the most prevalent mutation in ARX . ARX PAE produces a decrease expression of ARX in GEOs, and an enhancement in interneuron migration. That accelerated migration is cell autonomously driven, and it can be rescued by inhibiting CXCR4. We also found that PAE mutations result in an early increase in radial glia cells and intermediate progenitor cells, followed by a subsequent loss of cortical neurons at later timepoints. Moreover, ARX expression is upregulated in COs derived from patients at 30 DIV and is associated with alterations in the expression of CDKN1C . Furthermore, ARX PAE assembloids had hyperactivity which were evident at early stages of development. With effective treatments for infantile spasms and developmental epilepsies still elusive, delving into the role of ARX PAE mutations in human brain organoids represents a pivotal step toward uncovering groundbreaking therapeutic strategies.
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2
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Diana D, Pirone L, Russo L, D'Abrosca G, Madheswaran M, Benfante R, Di Lascio S, Caldinelli L, Fornasari D, Acconcia C, Corvino A, Ventserova N, Pollegioni L, Isernia C, Di Gaetano S, Malgieri G, Pedone EM, Fattorusso R. Structural characterization of PHOX2B and its DNA interaction shed light on the molecular basis of the +7Ala variant pathogenicity in CCHS. Chem Sci 2024; 15:8858-8872. [PMID: 38873078 PMCID: PMC11168103 DOI: 10.1039/d3sc06427a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/12/2024] [Indexed: 06/15/2024] Open
Abstract
An expansion of poly-alanine up to +13 residues in the C-terminus of the transcription factor PHOX2B underlies the onset of congenital central hypoventilation syndrome (CCHS). Recent studies demonstrated that the alanine tract expansion influences PHOX2B folding and activity. Therefore, structural information on PHOX2B is an important target for obtaining clues to elucidate the insurgence of the alanine expansion-related syndrome and also for defining a viable therapy. Here we report by NMR spectroscopy the structural characterization of the homeodomain (HD) of PHOX2B and HD + C-terminus PHOX2B protein, free and in the presence of the target DNA. The obtained structural data are then exploited to obtain a structural model of the PHOX2B-DNA interaction. In addition, the variant +7Ala, responsible for one of the most frequent forms of the syndrome, was analysed, showing different conformational proprieties in solution and a strong propensity to aggregation. Our data suggest that the elongated poly-alanine tract would be related to disease onset through a loss-of-function mechanism. Overall, this study paves the way for the future rational design of therapeutic drugs, suggesting as a possible therapeutic route the use of specific anti-aggregating molecules capable of preventing variant aggregation and possibly restoring the DNA-binding activity of PHOX2B.
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Affiliation(s)
- Donatella Diana
- CNR - Institute of Biostructures and Bioimaging Via Pietro Castellino 111 80131 Naples Italy
| | - Luciano Pirone
- CNR - Institute of Biostructures and Bioimaging Via Pietro Castellino 111 80131 Naples Italy
| | - Luigi Russo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Gianluca D'Abrosca
- Department of Clinical and Experimental Medicine - University of Foggia Viale Luigi Pinto 71122 Foggia Italy
| | - Manoj Madheswaran
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano Milan Italy
- CNR - Institute of Neuroscience Vedano Al Lambro (MB) Italy
- NeuroMi - Milan Center for Neuroscience, University of Milano Bicocca Milan Italy
| | - Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano Milan Italy
| | - Laura Caldinelli
- Department of Biotechnology and Life Sciences, University of Insubria Via J.H. Dunant 3 21100 Varese Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano Milan Italy
| | - Clementina Acconcia
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Andrea Corvino
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Nataliia Ventserova
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria Via J.H. Dunant 3 21100 Varese Italy
| | - Carla Isernia
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Sonia Di Gaetano
- CNR - Institute of Biostructures and Bioimaging Via Pietro Castellino 111 80131 Naples Italy
| | - Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
| | - Emilia M Pedone
- CNR - Institute of Biostructures and Bioimaging Via Pietro Castellino 111 80131 Naples Italy
| | - Roberto Fattorusso
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies - University of Campania "Luigi Vanvitelli" Via Vivaldi 43 81100 Caserta Italy
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3
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Amer-Sarsour F, Falik D, Berdichevsky Y, Kordonsky A, Eid S, Rabinski T, Ishtayeh H, Cohen-Adiv S, Braverman I, Blumen SC, Laviv T, Prag G, Vatine GD, Ashkenazi A. Disease-associated polyalanine expansion mutations impair UBA6-dependent ubiquitination. EMBO J 2024; 43:250-276. [PMID: 38177505 PMCID: PMC10897158 DOI: 10.1038/s44318-023-00018-9] [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: 07/06/2023] [Revised: 11/23/2023] [Accepted: 12/01/2023] [Indexed: 01/06/2024] Open
Abstract
Expansion mutations in polyalanine stretches are associated with a growing number of diseases sharing a high degree of genotypic and phenotypic commonality. These similarities prompted us to query the normal function of physiological polyalanine stretches and to investigate whether a common molecular mechanism is involved in these diseases. Here, we show that UBA6, an E1 ubiquitin-activating enzyme, recognizes a polyalanine stretch within its cognate E2 ubiquitin-conjugating enzyme USE1. Aberrations in this polyalanine stretch reduce ubiquitin transfer to USE1 and, subsequently, polyubiquitination and degradation of its target, the ubiquitin ligase E6AP. Furthermore, we identify competition for the UBA6-USE1 interaction by various proteins with polyalanine expansion mutations in the disease state. The deleterious interactions of expanded polyalanine tract proteins with UBA6 in mouse primary neurons alter the levels and ubiquitination-dependent degradation of E6AP, which in turn affects the levels of the synaptic protein Arc. These effects are also observed in induced pluripotent stem cell-derived autonomic neurons from patients with polyalanine expansion mutations, where UBA6 overexpression increases neuronal resilience to cell death. Our results suggest a shared mechanism for such mutations that may contribute to the congenital malformations seen in polyalanine tract diseases.
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Affiliation(s)
- Fatima Amer-Sarsour
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Daniel Falik
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel
- The Zelman Center for Neuroscience, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel
| | - Yevgeny Berdichevsky
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Alina Kordonsky
- School of Neurobiology, Biochemistry and Biophysics, the George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Sharbel Eid
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Tatiana Rabinski
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel
| | - Hasan Ishtayeh
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Stav Cohen-Adiv
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Itzhak Braverman
- Department of Otolaryngology, Head and Neck Surgery, Hillel Yaffe Medical Center, Hadera, Israel
- Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Sergiu C Blumen
- Rappaport Faculty of Medicine, Technion, Haifa, Israel
- Department of Neurology, Hillel Yaffe Medical Center, Hadera, Israel
| | - Tal Laviv
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Gali Prag
- School of Neurobiology, Biochemistry and Biophysics, the George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Gad D Vatine
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel.
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel.
- The Zelman Center for Neuroscience, Ben-Gurion University of the Negev, 8410501, Beer Sheva, Israel.
| | - Avraham Ashkenazi
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel.
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4
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Zhang S, Pei G, Li B, Li P, Lin Y. Abnormal phase separation of biomacromolecules in human diseases. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1133-1152. [PMID: 37475546 PMCID: PMC10423695 DOI: 10.3724/abbs.2023139] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Membrane-less organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are associated with numerous important biological functions, but the abnormal phase separation will also dysregulate the physiological processes. Emerging evidence points to the importance of LLPS in human health and diseases. Nevertheless, despite recent advancements, our knowledge of the molecular relationship between LLPS and diseases is frequently incomplete. In this review, we outline our current understanding about how aberrant LLPS affects developmental disorders, tandem repeat disorders, cancers and viral infection. We also examine disease mechanisms driven by aberrant condensates, and highlight potential treatment approaches. This study seeks to expand our understanding of LLPS by providing a valuable new paradigm for understanding phase separation and human disorders, as well as to further translate our current knowledge regarding LLPS into therapeutic discoveries.
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Affiliation(s)
- Songhao Zhang
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Gaofeng Pei
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Boya Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Pilong Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Yi Lin
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
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5
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Guo G, Wang X, Zhang Y, Li T. Sequence variations of phase-separating proteins and resources for studying biomolecular condensates. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1119-1132. [PMID: 37464880 PMCID: PMC10423696 DOI: 10.3724/abbs.2023131] [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: 04/13/2023] [Accepted: 06/06/2023] [Indexed: 07/20/2023] Open
Abstract
Phase separation (PS) is an important mechanism underlying the formation of biomolecular condensates. Physiological condensates are associated with numerous biological processes, such as transcription, immunity, signaling, and synaptic transmission. Changes in particular amino acids or segments can disturb the protein's phase behavior and interactions with other biomolecules in condensates. It is thus presumed that variations in the phase-separating-prone domains can significantly impact the properties and functions of condensates. The dysfunction of condensates contributes to a number of pathological processes. Pharmacological perturbation of these condensates is proposed as a promising way to restore physiological states. In this review, we characterize the variations observed in PS proteins that lead to aberrant biomolecular compartmentalization. We also showcase recent advancements in bioinformatics of membraneless organelles (MLOs), focusing on available databases useful for screening PS proteins and describing endogenous condensates, guiding researchers to seek the underlying pathogenic mechanisms of biomolecular condensates.
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Affiliation(s)
- Gaigai Guo
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Xinxin Wang
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Yi Zhang
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Tingting Li
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
- Key Laboratory for NeuroscienceMinistry of Education/National Health Commission of ChinaPeking UniversityBeijing100191China
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6
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Barbosa Pereira PJ, Manso JA, Macedo-Ribeiro S. The structural plasticity of polyglutamine repeats. Curr Opin Struct Biol 2023; 80:102607. [PMID: 37178477 DOI: 10.1016/j.sbi.2023.102607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 05/15/2023]
Abstract
From yeast to humans, polyglutamine (polyQ) repeat tracts are found frequently in the proteome and are particularly prominent in the activation domains of transcription factors. PolyQ is a polymorphic motif that modulates functional protein-protein interactions and aberrant self-assembly. Expansion of the polyQ repeated sequences beyond critical physiological repeat length thresholds triggers self-assembly and is linked to severe pathological implications. This review provides an overview of the current knowledge on the structures of polyQ tracts in the soluble and aggregated states and discusses the influence of neighboring regions on polyQ secondary structure, aggregation, and fibril morphologies. The influence of the genetic context of the polyQ-encoding trinucleotides is briefly discussed as a challenge for future endeavors in this field.
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Affiliation(s)
- Pedro José Barbosa Pereira
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal.
| | - José A Manso
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal; Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
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7
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Odelin G, Faucherre A, Marchese D, Pinard A, Jaouadi H, Le Scouarnec S, Chiarelli R, Achouri Y, Faure E, Herbane M, Théron A, Avierinos JF, Jopling C, Collod-Béroud G, Rezsohazy R, Zaffran S. Variations in the poly-histidine repeat motif of HOXA1 contribute to bicuspid aortic valve in mouse and zebrafish. Nat Commun 2023; 14:1543. [PMID: 36941270 PMCID: PMC10027860 DOI: 10.1038/s41467-023-37110-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 03/02/2023] [Indexed: 03/23/2023] Open
Abstract
Bicuspid aortic valve (BAV), the most common cardiovascular malformation occurs in 0.5-1.2% of the population. Although highly heritable, few causal mutations have been identified in BAV patients. Here, we report the targeted sequencing of HOXA1 in a cohort of BAV patients and the identification of rare indel variants in the homopolymeric histidine tract of HOXA1. In vitro analysis shows that disruption of this motif leads to a significant reduction in protein half-life and defective transcriptional activity of HOXA1. In zebrafish, targeting hoxa1a ortholog results in aortic valve defects. In vivo assays indicates that these variants behave as dominant negatives leading abnormal valve development. In mice, deletion of Hoxa1 leads to BAV with a very small, rudimentary non-coronary leaflet. We also show that 17% of homozygous Hoxa1-1His knock-in mice present similar phenotype. Genetic lineage tracing in Hoxa1-/- mutant mice reveals an abnormal reduction of neural crest-derived cells in the valve leaflet, which is caused by a failure of early migration of these cells.
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Affiliation(s)
- Gaëlle Odelin
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
| | - Adèle Faucherre
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Damien Marchese
- Animal Molecular and Cellular Biology group, Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, 5 (L7.07.10) place Croix du Sud, 1348, Louvain-la-Neuve, Belgium
| | - Amélie Pinard
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
| | - Hager Jaouadi
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
| | | | | | - Raphaël Chiarelli
- Animal Molecular and Cellular Biology group, Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, 5 (L7.07.10) place Croix du Sud, 1348, Louvain-la-Neuve, Belgium
| | - Younes Achouri
- Transgenesis Platform, de Duve Institute, Université Catholique de Louvain, 1200, Brussels, Belgium
| | - Emilie Faure
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
| | - Marine Herbane
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
| | - Alexis Théron
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
- Service de Chirurgie Cardiaque, AP-HM, Hôpital de la Timone, 13005, Marseille, France
| | - Jean-François Avierinos
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France
- Service de Cardiologie, AP-HM, Hôpital de la Timone, 13005, Marseille, France
| | - Chris Jopling
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | | | - René Rezsohazy
- Animal Molecular and Cellular Biology group, Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, 5 (L7.07.10) place Croix du Sud, 1348, Louvain-la-Neuve, Belgium
| | - Stéphane Zaffran
- Aix Marseille Univ, INSERM, MMG, U1251, 13005, Marseille, France.
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8
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Chen X, Zhao F, Xu Y, Cao Y, Li S, Zhang X, Zhao X. Clinical and genetic analysis in Chinese families with synpolydactyly, and cellular localization of HOXD13 with different length of polyalanine tract. Front Genet 2023; 14:1105046. [PMID: 37035736 PMCID: PMC10073534 DOI: 10.3389/fgene.2023.1105046] [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: 11/22/2022] [Accepted: 02/09/2023] [Indexed: 04/11/2023] Open
Abstract
Synpolydactyly (SPD) is caused by mutations in the transcription factor gene HOXD13. Such mutations include polyalanine expansion (PAE), but further study is required for the phenotypic spectrum characteristics of HOXD13 PAE. We investigated four unrelated Chinese families with significant limb malformations. Three PAEs were found in the HOXD13 polyalanine coding region: c.172_192dup (p.Ala58_Ala64dup) in Family 1, c.169_192dup (p.Ala57_Ala64dup) in Family 2, and c.183_210dup (p.Ala62_Ala70dup) in Family 3 and Family 4. Interestingly, we identified a new manifestation of preaxial polydactyly in both hands in a pediatric patient with an expansion of seven alanines, a phenotype not previously noted in SPD patients. Comparing with the wild-type cells and mutant cells with polyalanine contractions (PACs), the HOXD13 protein with a PAE of nine-alanine or more was difficult to enter the nucleus, and easy to form inclusion bodies in the cytoplasm, and with the increase of PAE, the more inclusion bodies were formed. This study not only expanded the phenotypic spectrum of SPD, but also enriched our understanding of its pathogenic mechanisms.
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Affiliation(s)
| | | | | | | | | | - Xue Zhang
- *Correspondence: Xue Zhang, ; Xiuli Zhao,
| | - Xiuli Zhao
- *Correspondence: Xue Zhang, ; Xiuli Zhao,
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9
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Kurokawa R, Kurokawa M, Mitsutake A, Nakaya M, Baba A, Nakata Y, Moritani T, Abe O. Clinical and neuroimaging review of triplet repeat diseases. Jpn J Radiol 2023; 41:115-130. [PMID: 36169768 PMCID: PMC9889482 DOI: 10.1007/s11604-022-01343-5] [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: 08/30/2022] [Accepted: 09/18/2022] [Indexed: 02/04/2023]
Abstract
Triplet repeat diseases (TRDs) refer to a group of diseases caused by three nucleotide repeats elongated beyond a pathologic threshold. TRDs are divided into the following four groups depending on the pathomechanisms, although the pathomechanisms of several diseases remain unelucidated: polyglutamine disorders, caused by a pathologic repeat expansion of CAG (coding the amino acid glutamine) located within the exon; loss-of-function repeat disorders, characterized by the common feature of a loss of function of the gene within which they occur; RNA gain-of-function disorders, involving the production of a toxic RNA species; and polyalanine disorders, caused by a pathologic repeat expansion of GCN (coding the amino acid alanine) located within the exon. Many of these TRDs manifest through neurologic symptoms; moreover, neuroimaging, especially brain magnetic resonance imaging, plays a pivotal role in the detection of abnormalities, differentiation, and management of TRDs. In this article, we reviewed the clinical and neuroimaging features of TRDs. An early diagnosis of TRDs through clinical and imaging approaches is important and may contribute to appropriate medical intervention for patients and their families.
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Affiliation(s)
- Ryo Kurokawa
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan ,Division of Neuroradiology, Department of Radiology, University of Michigan, 1500 E Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Mariko Kurokawa
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan ,Division of Neuroradiology, Department of Radiology, University of Michigan, 1500 E Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Akihiko Mitsutake
- Department of Neurology, International University of Health and Welfare, Mita Hospital, 1-4-3 Mita, Minato-ku, Tokyo, 108-8329 Japan
| | - Moto Nakaya
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
| | - Akira Baba
- Division of Neuroradiology, Department of Radiology, University of Michigan, 1500 E Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Yasuhiro Nakata
- Department of Neuroradiology, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, Tokyo 183-0042 Japan
| | - Toshio Moritani
- Division of Neuroradiology, Department of Radiology, University of Michigan, 1500 E Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
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10
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Mier P, Elena-Real CA, Cortés J, Bernadó P, Andrade-Navarro MA. The sequence context in poly-alanine regions: structure, function and conservation. Bioinformatics 2022; 38:4851-4858. [PMID: 36106994 PMCID: PMC9620824 DOI: 10.1093/bioinformatics/btac610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/07/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
MOTIVATION Poly-alanine (polyA) regions are protein stretches mostly composed of alanines. Despite their abundance in eukaryotic proteomes and their association to nine inherited human diseases, the structural and functional roles exerted by polyA stretches remain poorly understood. In this work we study how the amino acid context in which polyA regions are settled in proteins influences their structure and function. RESULTS We identified glycine and proline as the most abundant amino acids within polyA and in the flanking regions of polyA tracts, in human proteins as well as in 17 additional eukaryotic species. Our analyses indicate that the non-structuring nature of these two amino acids influences the α-helical conformations predicted for polyA, suggesting a relevant role in reducing the inherent aggregation propensity of long polyA. Then, we show how polyA position in protein N-termini relates with their function as transit peptides. PolyA placed just after the initial methionine is often predicted as part of mitochondrial transit peptides, whereas when placed in downstream positions, polyA are part of signal peptides. A few examples from known structures suggest that short polyA can emerge by alanine substitutions in α-helices; but evolution by insertion is observed for longer polyA. Our results showcase the importance of studying the sequence context of homorepeats as a mechanism to shape their structure-function relationships. AVAILABILITY AND IMPLEMENTATION The datasets used and/or analyzed during the current study are available from the corresponding author onreasonable request. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Pablo Mier
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Carlos A Elena-Real
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 34090 Montpellier, France
| | - Juan Cortés
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 34090 Montpellier, France
| | - Miguel A Andrade-Navarro
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
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CGG repeat expansion in NOTCH2NLC causes mitochondrial dysfunction and progressive neurodegeneration in Drosophila model. Proc Natl Acad Sci U S A 2022; 119:e2208649119. [PMID: 36191230 PMCID: PMC9565157 DOI: 10.1073/pnas.2208649119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal intranuclear inclusion disease (NIID) is a neuromuscular/neurodegenerative disease caused by the expansion of CGG repeats in the 5' untranslated region (UTR) of the NOTCH2NLC gene. These repeats can be translated into a polyglycine-containing protein, uN2CpolyG, which forms protein inclusions and is toxic in cell models, albeit through an unknown mechanism. Here, we established a transgenic Drosophila model expressing uN2CpolyG in multiple systems, which resulted in progressive neuronal cell loss, locomotor deficiency, and shortened lifespan. Interestingly, electron microscopy revealed mitochondrial swelling both in transgenic flies and in muscle biopsies of individuals with NIID. Immunofluorescence and immunoelectron microscopy showed colocalization of uN2CpolyG with mitochondria in cell and patient samples, while biochemical analysis revealed that uN2CpolyG interacted with a mitochondrial RNA binding protein, LRPPRC (leucine-rich pentatricopeptide repeat motif-containing protein). Furthermore, RNA sequencing (RNA-seq) analysis and functional assays showed down-regulated mitochondrial oxidative phosphorylation in uN2CpolyG-expressing flies and NIID muscle biopsies. Finally, idebenone treatment restored mitochondrial function and alleviated neurodegenerative phenotypes in transgenic flies. Overall, these results indicate that transgenic flies expressing uN2CpolyG recapitulate key features of NIID and that reversing mitochondrial dysfunction might provide a potential therapeutic approach for this disorder.
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Deletion of a previously uncharacterized lipoprotein lirL confers resistance to an inhibitor of type II signal peptidase in Acinetobacter baumannii. Proc Natl Acad Sci U S A 2022; 119:e2123117119. [PMID: 36099298 PMCID: PMC9499571 DOI: 10.1073/pnas.2123117119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Inhibiting bacterial lipoprotein biosynthesis in Enterobacteriaceae is an attractive antibacterial strategy to target multidrug resistance, and mechanisms of resistance to prolipoprotein signal peptidase (LspA) inhibitors in Escherichia coli are relatively well understood. In contrast, it has been challenging to understand the mechanisms of resistance to LspA inhibitors in Acinetobacter baumannii due to the substantially lower inhibitor potencies and the lack of a homologous lpp gene. By increasing the antibacterial potency of the LspA inhibitor, globomycin, against wild-type A. baumannii, we were able to examine resistance to LspA inhibitors, resulting in the identification of a previously uncharacterized highly abundant lipoprotein, LspA inhibitor resistance lipoprotein. This study reveals insights into resistance mechanisms of A. baumannii against inhibitors of bacterial lipoprotein biosynthesis. Acinetobacter baumannii is a clinically important, predominantly health care–associated gram-negative bacterium with high rates of emerging resistance worldwide. Given the urgent need for novel antibacterial therapies against A. baumannii, we focused on inhibiting lipoprotein biosynthesis, a pathway that is essential for envelope biogenesis in gram-negative bacteria. The natural product globomycin, which inhibits the essential type II signal peptidase prolipoprotein signal peptidase (LspA), is ineffective against wild-type A. baumannii clinical isolates due to its poor penetration through the outer membrane. Here, we describe a globomycin analog, G5132, that is more potent against wild-type and clinical A. baumannii isolates. Mutations leading to G5132 resistance in A. baumannii map to the signal peptide of a single hypothetical gene, which we confirm encodes an alanine-rich lipoprotein and have renamed lirL (prolipoprotein signal peptidase inhibitor resistance lipoprotein). LirL is a highly abundant lipoprotein primarily localized to the inner membrane. Deletion of lirL leads to G5132 resistance, inefficient cell division, increased sensitivity to serum, and attenuated virulence. Signal peptide mutations that confer resistance to G5132 lead to the accumulation of diacylglyceryl-modified LirL prolipoprotein in untreated cells without significant loss in cell viability, suggesting that these mutations overcome a block in lipoprotein biosynthetic flux by decreasing LirL prolipoprotein substrate sensitivity to processing by LspA. This study characterizes a lipoprotein that plays a critical role in resistance to LspA inhibitors and validates lipoprotein biosynthesis as a antibacterial target in A. baumannii.
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Böker A, Paul W. Thermodynamics and Conformations of Single Polyalanine, Polyserine, and Polyglutamine Chains within the PRIME20 Model. J Phys Chem B 2022; 126:7286-7297. [DOI: 10.1021/acs.jpcb.2c04360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arne Böker
- Institut für Physik, Martin Luther-Universität Halle-Wittenberg, von Seckendorff Platz 1, 06120 Halle, Germany
| | - Wolfgang Paul
- Institut für Physik, Martin Luther-Universität Halle-Wittenberg, von Seckendorff Platz 1, 06120 Halle, Germany
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Ramírez de Mingo D, Pantoja-Uceda D, Hervás R, Carrión-Vázquez M, Laurents DV. Conformational dynamics in the disordered region of human CPEB3 linked to memory consolidation. BMC Biol 2022; 20:129. [PMID: 35658951 PMCID: PMC9166367 DOI: 10.1186/s12915-022-01310-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 04/25/2022] [Indexed: 11/10/2022] Open
Abstract
Background Current understanding of the molecular basis of memory consolidation points to an important function of amyloid formation by neuronal-specific isoforms of the cytoplasmic polyadenylation element binding (CPEB) protein family. In particular, CPEB is thought to promote memory persistence through formation of self-sustaining prion-like amyloid assemblies at synapses, mediated by its intrinsically disordered region (IDR) and leading to permanent physical alterations at the basis of memory persistence. Although the molecular mechanisms by which amyloid formation takes place in CPEB have been described in invertebrates, the way amyloid formation occurs in the human homolog CPEB3 (hCPEB3) remains unclear. Here, we characterize by NMR spectroscopy the atomic level conformation and ps-ms dynamics of the 426-residue IDR of hCPEB3, which has been associated with episodic memory in humans. Results We show that the 426-residue N-terminal region of hCPEB3 is a dynamic, intrinsically disordered region (IDR) which lacks stable folded structures. The first 29 residues, M1QDDLLMDKSKTQPQPQQQQRQQQQPQP29, adopt a helical + disordered motif, and residues 86–93: P83QQPPPP93, and 166–175: P166PPPAPAPQP175 form polyproline II (PPII) helices. The (VG)5 repeat motif is completely disordered, and residues 200–250 adopt three partially populated α-helices. Residues 345–355, which comprise the nuclear localization signal (NLS), form a modestly populated α-helix which may mediate STAT5B binding. These findings allow us to suggest a model for nascent hCPEB3 structural transitions at single residue resolution, advancing that amyloid breaker residues, like proline, are a key difference between functional versus pathological amyloids. Conclusion Our NMR spectroscopic analysis of hCPEB3 provides insights into the first structural transitions involved in protein–protein and protein-mRNA interactions. The atomic level understanding of these structural transitions involved in hCPEB3 aggregation is a key first step toward understanding memory persistence in humans, as well as sequence features that differentiate beneficial amyloids from pathological ones. Areas Biophysics, Structural Biology, Biochemistry & Neurosciences. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01310-6.
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Boivin M, Charlet-Berguerand N. Trinucleotide CGG Repeat Diseases: An Expanding Field of Polyglycine Proteins? Front Genet 2022; 13:843014. [PMID: 35295941 PMCID: PMC8918734 DOI: 10.3389/fgene.2022.843014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/31/2022] [Indexed: 12/30/2022] Open
Abstract
Microsatellites are repeated DNA sequences of 3–6 nucleotides highly variable in length and sequence and that have important roles in genomes regulation and evolution. However, expansion of a subset of these microsatellites over a threshold size is responsible of more than 50 human genetic diseases. Interestingly, some of these disorders are caused by expansions of similar sequences, sizes and localizations and present striking similarities in clinical manifestations and histopathological features, which suggest a common mechanism of disease. Notably, five identical CGG repeat expansions, but located in different genes, are the causes of fragile X-associated tremor/ataxia syndrome (FXTAS), neuronal intranuclear inclusion disease (NIID), oculopharyngodistal myopathy type 1 to 3 (OPDM1-3) and oculopharyngeal myopathy with leukoencephalopathy (OPML), which are neuromuscular and neurodegenerative syndromes with overlapping symptoms and similar histopathological features, notably the presence of characteristic eosinophilic ubiquitin-positive intranuclear inclusions. In this review we summarize recent finding in neuronal intranuclear inclusion disease and FXTAS, where the causing CGG expansions were found to be embedded within small upstream ORFs (uORFs), resulting in their translation into novel proteins containing a stretch of polyglycine (polyG). Importantly, expression of these polyG proteins is toxic in animal models and is sufficient to reproduce the formation of ubiquitin-positive intranuclear inclusions. These data suggest the existence of a novel class of human genetic pathology, the polyG diseases, and question whether a similar mechanism may exist in other diseases, notably in OPDM and OPML.
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16
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Joz Abbasalian Z, Khanahmad H, Tabatabaiefar MA. Bisulfite Treatment of CG-Rich Track of Trinucleotide Repeat Expansion Disorder: Make the Sequence Less CG Rich. Adv Biomed Res 2022; 10:46. [PMID: 35127573 PMCID: PMC8781891 DOI: 10.4103/abr.abr_144_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/03/2019] [Accepted: 12/15/2020] [Indexed: 11/08/2022] Open
Abstract
Background: Trinucleotide repeat (TNR) expansion is a kind of mutation with instability in the number of microsatellite repeats. This nature of mutation leads to the different kinds of neurological and neuromuscular disorders; among them, fragile-X syndrome is the main cause of intellectual disability in which the increasing number of CGG TNR in 5' untranslated region is the main reason for epigenetic silencing of Fragile X mental retardation 1 gene. The aim of this study is to decrease the CG content of the candidate region to facilitate amplification by conventional polymerase chain reaction (PCR). Bisulfite treatment of the genomic DNA results in conversion of unmethylated cytosine to uridine and may overcome the diagnostic pitfalls. Materials and Methods: The whole blood DNA was extracted and bisulfite treated. Then any simplification in PCR process of desire sequence were assayed through following conventional PCR using specifically designed primers for converted sequence. Bisulfite-treated PCR product of a nearby sequence confirmed our results as a conversion control. Results: Both the control and the candidate sequences undergoing bisulfite treatment were successfully amplified by PCR. Conclusions: Decreasing the GC content of the sequence by bisulfite treating could be a new approach to overcome difficulties in amplifying GC-rich sequences.
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Affiliation(s)
- Zahra Joz Abbasalian
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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The molecular pathogenesis of repeat expansion diseases. Biochem Soc Trans 2021; 50:119-134. [PMID: 34940797 DOI: 10.1042/bst20200143] [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: 09/24/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 12/28/2022]
Abstract
Expanded short tandem repeats in the genome cause various monogenic diseases, particularly neurological disorders. Since the discovery of a CGG repeat expansion in the FMR1 gene in 1991, more than 40 repeat expansion diseases have been identified to date. In the coding repeat expansion diseases, in which the expanded repeat sequence is located in the coding regions of genes, the toxicity of repeat polypeptides, particularly misfolding and aggregation of proteins containing an expanded polyglutamine tract, have been the focus of investigation. On the other hand, in the non-coding repeat expansion diseases, in which the expanded repeat sequence is located in introns or untranslated regions, the toxicity of repeat RNAs has been the focus of investigation. Recently, these repeat RNAs were demonstrated to be translated into repeat polypeptides by the novel mechanism of repeat-associated non-AUG translation, which has extended the research direction of the pathological mechanisms of this disease entity to include polypeptide toxicity. Thus, a common pathogenesis has been suggested for both coding and non-coding repeat expansion diseases. In this review, we briefly outline the major pathogenic mechanisms of repeat expansion diseases, including a loss-of-function mechanism caused by repeat expansion, repeat RNA toxicity caused by RNA foci formation and protein sequestration, and toxicity by repeat polypeptides. We also discuss perturbation of the physiological liquid-liquid phase separation state caused by these repeat RNAs and repeat polypeptides, as well as potential therapeutic approaches against repeat expansion diseases.
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18
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Howard CJ, Frost A. Ribosome-associated quality control and CAT tailing. Crit Rev Biochem Mol Biol 2021; 56:603-620. [PMID: 34233554 DOI: 10.1080/10409238.2021.1938507] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Translation is the set of mechanisms by which ribosomes decode genetic messages as they synthesize polypeptides of a defined amino acid sequence. While the ribosome has been honed by evolution for high-fidelity translation, errors are inevitable. Aberrant mRNAs, mRNA structure, defective ribosomes, interactions between nascent proteins and the ribosomal exit tunnel, and insufficient cellular resources, including low tRNA levels, can lead to functionally irreversible stalls. Life thus depends on quality control mechanisms that detect, disassemble and recycle stalled translation intermediates. Ribosome-associated Quality Control (RQC) recognizes aberrant ribosome states and targets their potentially toxic polypeptides for degradation. Here we review recent advances in our understanding of RQC in bacteria, fungi, and metazoans. We focus in particular on an unusual modification made to the nascent chain known as a "CAT tail", or Carboxy-terminal Alanine and Threonine tail, and the mechanisms by which ancient RQC proteins catalyze CAT-tail synthesis.
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Affiliation(s)
- Conor J Howard
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
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19
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Hand2 Selectively Reorganizes Chromatin Accessibility to Induce Pacemaker-like Transcriptional Reprogramming. Cell Rep 2020; 27:2354-2369.e7. [PMID: 31116981 PMCID: PMC6657359 DOI: 10.1016/j.celrep.2019.04.077] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/25/2019] [Accepted: 04/17/2019] [Indexed: 01/01/2023] Open
Abstract
Gata4, Hand2, Mef2c, and Tbx5 (GHMT) can reprogram transduced fibroblasts into induced pacemaker-like myocytes (iPMs), but the underlying mechanisms remain obscure. Here, we explore the role of Hand2 in iPM formation by using a combination of transcriptome, genome, and biochemical as-says. We found many shared transcriptional signatures between iPMs and the endogenous sinoatrial node (SAN), yet key regulatory networks remain missing. We demonstrate that Hand2 augments chromatin accessibility at loci involved in sarcomere organization, electrical coupling, and membrane depolarization. Focusing on an established cardiac Hand2 cistrome, we observe selective reorganization of chromatin accessibility to promote pacemaker-specific gene expression. Moreover, we identify a Hand2 cardiac subtype diversity (CSD) domain through biochemical analysis of the N terminus. By integrating our RNA-seq and ATAC-seq datasets, we highlight desmosome organization as a hallmark feature of iPM formation. Collectively, our results illuminate Hand2-dependent mechanisms that may guide future efforts to rationally improve iPM formation. Gata4, Hand2, Mef2c, and Tbx5 can reprogram fibroblasts into cardiomyocyte-like cells, including induced pacemakers (iPMs). Fernandez-Perez et al. show that Hand2 coordinates this process by influencing chromatin accessibility and gene expression in fibroblasts undergoing iPM lineage conversion. These insights could eventually inform the production of superior replacement cells.
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Basu S, Mackowiak SD, Niskanen H, Knezevic D, Asimi V, Grosswendt S, Geertsema H, Ali S, Jerković I, Ewers H, Mundlos S, Meissner A, Ibrahim DM, Hnisz D. Unblending of Transcriptional Condensates in Human Repeat Expansion Disease. Cell 2020; 181:1062-1079.e30. [PMID: 32386547 PMCID: PMC7261253 DOI: 10.1016/j.cell.2020.04.018] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/16/2020] [Accepted: 04/13/2020] [Indexed: 11/27/2022]
Abstract
Expansions of amino acid repeats occur in >20 inherited human disorders, and many occur in intrinsically disordered regions (IDRs) of transcription factors (TFs). Such diseases are associated with protein aggregation, but the contribution of aggregates to pathology has been controversial. Here, we report that alanine repeat expansions in the HOXD13 TF, which cause hereditary synpolydactyly in humans, alter its phase separation capacity and its capacity to co-condense with transcriptional co-activators. HOXD13 repeat expansions perturb the composition of HOXD13-containing condensates in vitro and in vivo and alter the transcriptional program in a cell-specific manner in a mouse model of synpolydactyly. Disease-associated repeat expansions in other TFs (HOXA13, RUNX2, and TBP) were similarly found to alter their phase separation. These results suggest that unblending of transcriptional condensates may underlie human pathologies. We present a molecular classification of TF IDRs, which provides a framework to dissect TF function in diseases associated with transcriptional dysregulation.
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Affiliation(s)
- Shaon Basu
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Sebastian D Mackowiak
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Henri Niskanen
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Dora Knezevic
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Vahid Asimi
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Stefanie Grosswendt
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Hylkje Geertsema
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany
| | - Salaheddine Ali
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany; Charité-Universitätsmedizin Berlin, BCRT-Berlin Institute of Health Center for Regenerative Therapies, 10178 Berlin, Germany
| | - Ivana Jerković
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Helge Ewers
- Institute for Chemistry and Biochemistry, Free University Berlin, 14195 Berlin, Germany
| | - Stefan Mundlos
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany; Charité-Universitätsmedizin Berlin, BCRT-Berlin Institute of Health Center for Regenerative Therapies, 10178 Berlin, Germany
| | - Alexander Meissner
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Daniel M Ibrahim
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany; Charité-Universitätsmedizin Berlin, BCRT-Berlin Institute of Health Center for Regenerative Therapies, 10178 Berlin, Germany
| | - Denes Hnisz
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany.
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A heterozygous duplication variant of the HOXD13 gene caused synpolydactyly type 1 with variable expressivity in a Chinese family. BMC MEDICAL GENETICS 2019; 20:203. [PMID: 31870337 PMCID: PMC6929446 DOI: 10.1186/s12881-019-0908-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 10/15/2019] [Indexed: 11/19/2022]
Abstract
Background Synpolydactyly type 1 (SPD1), also known as syndactyly type II, is an autosomal dominant limb deformity generally results in webbing of 3rd and 4th fingers, duplication of 4th or 5th toes. It is most commonly caused by mutation in HOXD13 gene. In this study, a five-generation Chinese family affected with SPD1 disease were collected. We tried to identify the pathogenic variations associated with SPD1 involved in the family. Methods We used the whole genome sequencing (WGS) to identify the pathogenic variant in this family which was later confirmed by PCR-Sanger sequencing. The genetic variation were evaluated with the frequencies in the 1000 Genome Project and Exome Aggregation Consortium (ExAC) dataset. The significance of variants were assessed using different mutation predictor softwares like Mutation Taster, PROVEAN and SIFT. The classification of variants was assessed according to American College of Medical Genetics and Genomics (ACMG) guidelines. Results Our results showed the mutation of 24-base pair duplication (c.183_206dupAGCGGCGGCTGCGGCGGCGGCGGC) in exon one of HOXD13 in heterozygous form which was predicted to result in eight extra alanine (A) residues in N-terminal domain of HOXD13 protein. The mutation was detected in all affected members of the family. Conclusion Based on our mutation analysis of variant c.183_206dupAGCGGCGGCTGCGGCGGCGGCGGC in HOXD13 and its cosegregation in all affected family members, we found this variant as likely pathogenic to this SPD1 family. Our study highlights variable expressivity of HOXD13 mutation. Our results also widen the spectrum of HOXD13 mutation responsible for SPD1.
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Fisher M, Smeiles C, Jnah AJ, Ruiz ME, Difiore T, Sewell K. Congenital Central Hypoventilation Syndrome: A Case-Based Learning Opportunity for Neonatal Clinicians. Neonatal Netw 2019; 38:217-225. [PMID: 31470390 DOI: 10.1891/0730-0832.38.4.217] [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] [Indexed: 06/10/2023]
Abstract
Congenital central hypoventilation syndrome (CCHS) is a rare and sporadic neurocristopathy characterized by alveolar hypoventilation and autonomic nervous system dysfunction. CCHS manifests quickly after birth, initially as respiratory distress. Mortality risk is estimated at 38 percent, with a median age of death of three months of age. A timely and accurate diagnosis is critical. Genetic testing for PHOX2B gene mutations is necessary to confirm the diagnosis; however, laboratory turnaround time often imposes an additional 7-14-day waiting period on an often anxious family. Neonatal clinicians should recognize that families require disease-specific education, emotional support, and time to rehearse daily caregiving in preparation for discharge. Therefore, this article presents the key clinical, pathophysiologic, and diagnostic factors, as well as a discussion of discharge needs. A case report of an infant, born to parents with no known history of CCHS, is included as a case-based learning opportunity for readers.
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Pirone L, Caldinelli L, Di Lascio S, Di Girolamo R, Di Gaetano S, Fornasari D, Pollegioni L, Benfante R, Pedone E. Molecular insights into the role of the polyalanine region in mediating PHOX2B aggregation. FEBS J 2019; 286:2505-2521. [PMID: 30955232 DOI: 10.1111/febs.14841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/27/2019] [Accepted: 04/04/2019] [Indexed: 11/26/2022]
Abstract
About 90% of congenital central hypoventilation syndrome (CCHS) patients show polyalanine triplet expansions in the coding region of transcription factor PHOX2B, which renders this protein an intriguing target to understand the insurgence of this syndrome and for the design of a novel therapeutical approach. Consistently with the role of PHOX2B as a transcriptional regulator, it is reasonable that a general transcriptional dysregulation caused by the polyalanine expansion might represent an important mechanism underlying CCHS pathogenesis. Therefore, this study focused on the biochemical characterization of different PHOX2B variants, such as a variant containing the correct C-terminal (20 alanines) stretch, one of the most frequent polyalanine expansions (+7 alanines), and a variant lacking the complete alanine stretch (0 alanines). Comparison of the different variants by a multidisciplinary approach based on different methodologies (including circular dichroism, spectrofluorimetry, light scattering, and Atomic Force Microscopy studies) highlighted the propensity to aggregate for the PHOX2B variant containing the polyalanine expansion (+7-alanines), especially in the presence of DNA, while the 0-alanines variant resembled the protein with the correct polyalanine length. Moreover, and unexpectedly, the formation of fibrils was revealed only for the pathological variant, suggesting a plausible role of such fibrils in the insurgence of CCHS.
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Affiliation(s)
- Luciano Pirone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
| | - Laura Caldinelli
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, Varese, Italy
| | - Simona Di Lascio
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | - Rocco Di Girolamo
- Department of Chemical Sciences, University of Naples Federico II, Italy
| | | | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, Varese, Italy
| | - Roberta Benfante
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy
- CNR- Neuroscience Institute, Milan, Italy
| | - Emilia Pedone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
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Banerjee A, Phillips BL, Deng Q, Seyfried NT, Pavlath GK, Vest KE, Corbett AH. Proteomic analysis reveals that wildtype and alanine-expanded nuclear poly(A)-binding protein exhibit differential interactions in skeletal muscle. J Biol Chem 2019; 294:7360-7376. [PMID: 30837270 DOI: 10.1074/jbc.ra118.007287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/19/2019] [Indexed: 12/22/2022] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, primarily autosomal dominant disease caused by a short GCN expansion in the PABPN1 (polyadenylate-binding protein nuclear 1) gene that results in an alanine expansion at the N terminus of the PABPN1 protein. Expression of alanine-expanded PABPN1 is linked to the formation of nuclear aggregates in tissues from individuals with OPMD. However, as with other nuclear aggregate-associated diseases, controversy exists over whether these aggregates are the direct cause of pathology. An emerging hypothesis is that a loss of PABPN1 function and/or aberrant protein interactions contribute to pathology in OPMD. Here, we present the first global proteomic analysis of the protein interactions of WT and alanine-expanded PABPN1 in skeletal muscle tissue. These data provide both insight into the function of PABPN1 in muscle and evidence that the alanine expansion alters the protein-protein interactions of PABPN1. We extended this analysis to demonstrate altered complex formation with and loss of function of TDP-43 (TAR DNA-binding protein 43), which we show interacts with alanine-expanded but not WT PABPN1. The results from our study support a model where altered protein interactions with alanine-expanded PABPN1 that lead to loss or gain of function could contribute to pathology in OPMD.
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Affiliation(s)
| | - Brittany L Phillips
- From the Department of Biology and.,the Graduate Program in Genetics and Molecular Biology, Emory University, Atlanta, Georgia 30322
| | - Quidong Deng
- the Department of Biochemistry, Center for Neurodegenerative Diseases and
| | | | - Grace K Pavlath
- the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Katherine E Vest
- the Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267
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25
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WITHDRAWN: A 24-base pair duplication in exon one of HOXD13 gene linked to synpolydactyly type 1 in a Chinese family. Meta Gene 2018. [DOI: 10.1016/j.mgene.2018.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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26
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Aviolat H, Nominé Y, Gioria S, Bonhoure A, Hoffmann D, Ruhlmann C, Nierengarten H, Ruffenach F, Villa P, Trottier Y, Klein FAC. SynAggreg: A Multifunctional High-Throughput Technology for Precision Study of Amyloid Aggregation and Systematic Discovery of Synergistic Inhibitor Compounds. J Mol Biol 2018; 430:5257-5279. [PMID: 30266595 DOI: 10.1016/j.jmb.2018.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/30/2018] [Accepted: 09/11/2018] [Indexed: 11/19/2022]
Abstract
Numerous proteins can coalesce into amyloid self-assemblies, which are responsible for a class of diseases called amyloidoses, but which can also fulfill important biological functions and are of great interest for biotechnology. Amyloid aggregation is a complex multi-step process, poorly prone to detailed structural studies. Therefore, small molecules interacting with amyloids are often used as tools to probe the amyloid aggregation pathway and in some cases to treat amyloidoses as they prevent pathogenic protein aggregation. Here, we report on SynAggreg, an in vitro high-throughput (HT) platform dedicated to the precision study of amyloid aggregation and the effect of modulator compounds. SynAggreg relies on an accurate bi-fluorescent amyloid-tracer readout that overcomes some limitations of existing HT methods. It allows addressing diverse aspects of aggregation modulation that are critical for pathomechanistic studies, such as the specificity of compounds toward various amyloids and their effects on aggregation kinetics, as well as the co-assembly propensity of distinct amyloids and the influence of prion-like seeding on self-assembly. Furthermore, SynAggreg is the first HT technology that integrates tailored methodology to systematically identify synergistic compound combinations-an emerging strategy to improve fatal amyloidoses by targeting multiple steps of the aggregation pathway. To this end, we apply analytical combinatorial scores to rank the inhibition efficiency of couples of compounds and to readily detect synergism. Finally, the SynAggreg platform should be suited for the characterization of a broad class of amyloids, whether of interest for drug development purposes, for fundamental research on amyloid functions, or for biotechnological applications.
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Affiliation(s)
- Hubert Aviolat
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - Yves Nominé
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - Sophie Gioria
- University of Strasbourg, Strasbourg, France; Integrative Biological Chemistry Platform of Strasbourg, Illkirch, France
| | - Anna Bonhoure
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - David Hoffmann
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - Christine Ruhlmann
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - Hélène Nierengarten
- University of Strasbourg, Strasbourg, France; Institut de Chimie de Strasbourg, UMR7177, Strasbourg, France
| | - Frank Ruffenach
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France
| | - Pascal Villa
- University of Strasbourg, Strasbourg, France; Integrative Biological Chemistry Platform of Strasbourg, Illkirch, France; Centre National de la Recherche Scientifique, UMS 3286, Illkirch, France
| | - Yvon Trottier
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France.
| | - Fabrice A C Klein
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; University of Strasbourg, Strasbourg, France.
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27
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Does the Polymorphism in the Length of the Polyalanine Tract of FOXE1 Gene Influence the Risk of Thyroid Dysgenesis Occurrence? J Thyroid Res 2018; 2017:2793205. [PMID: 29479488 PMCID: PMC5727785 DOI: 10.1155/2017/2793205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 11/06/2017] [Indexed: 11/17/2022] Open
Abstract
Background. Recent data have suggested that polymorphisms in the length of the polyalanine tract (polyA) of FOXE1 gene may act as a susceptibility factor for thyroid dysgenesis. The main purpose of this study was to investigate the influence of polyA of FOXE1 gene on the risk of thyroid dysgenesis. Method. A case-control study was conducted in a sample of 90 Brazilian patients with thyroid dysgenesis and 131 controls without family history of thyroid disease. Genomic DNA was isolated from peripheral blood samples and the genotype of each individual was determined by automated sequencing. Results. More than 90% of genotypes found in the group of patients with thyroid dysgenesis and in controls subjects were represented by sizes 14 and 16 polymorphisms in the following combinations: 14/14, 14/16, and 16/16. Genotypes 14/16 and 16/16 were more frequent in the control group, while genotype 14/14 was more frequent in the group of patients with thyroid dysgenesis. There was no difference between agenesis group and control group. Genotype 14/14 when compared to genotypes 14/16 and 16/16A showed an association with thyroid dysgenesis. Conclusion. PolyA of FOXE1 gene alters the risk of thyroid dysgenesis, which may explain in part the etiology of this disease.
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28
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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29
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Li L, Ng NKL, Koon AC, Chan HYE. Expanded polyalanine tracts function as nuclear export signals and promote protein mislocalization via eEF1A1 factor. J Biol Chem 2017; 292:5784-5800. [PMID: 28246169 DOI: 10.1074/jbc.m116.763599] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/24/2017] [Indexed: 12/14/2022] Open
Abstract
Polyalanine (poly(A)) diseases are caused by the expansion of translated GCN triplet nucleotide sequences encoding poly(A) tracts in proteins. To date, nine human disorders have been found to be associated with poly(A) tract expansions, including congenital central hypoventilation syndrome and oculopharyngeal muscular dystrophy. Previous studies have demonstrated that unexpanded wild-type poly(A)-containing proteins localize to the cell nucleus, whereas expanded poly(A)-containing proteins primarily localize to the cytoplasm. Because most of these poly(A) disease proteins are transcription factors, this mislocalization causes cellular transcriptional dysregulation leading to cellular dysfunction. Correcting this faulty localization could potentially point to strategies to treat the aforementioned disorders, so there is a pressing need to identify the mechanisms underlying the mislocalization of expanded poly(A) protein. Here, we performed a glutathione S-transferase pulldown assay followed by mass spectrometry and identified eukaryotic translation elongation factor 1 α1 (eEF1A1) as an interacting partner with expanded poly(A)-containing proteins. Strikingly, knockdown of eEF1A1 expression partially corrected the mislocalization of the expanded poly(A) proteins in the cytoplasm and restored their functions in the nucleus. We further demonstrated that the expanded poly(A) domain itself can serve as a nuclear export signal. Taken together, this study demonstrates that eEF1A1 regulates the subcellular location of expanded poly(A) proteins and is therefore a potential therapeutic target for combating the pathogenesis of poly(A) diseases.
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Affiliation(s)
- Li Li
- From the Laboratory of Drosophila Research.,Biochemistry Program
| | - Nelson Ka Lam Ng
- From the Laboratory of Drosophila Research.,Biochemistry Program
| | - Alex Chun Koon
- From the Laboratory of Drosophila Research.,Biochemistry Program
| | - Ho Yin Edwin Chan
- From the Laboratory of Drosophila Research, .,Biochemistry Program.,Cell and Molecular Biology Program, and.,Molecular Biotechnology Program, School of Life Sciences, Faculty of Science, and.,the Gerald Choa Neuroscience Centre, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
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30
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Nikitski AV, Rogounovitch TI, Bychkov A, Takahashi M, Yoshiura KI, Mitsutake N, Kawaguchi T, Matsuse M, Drozd VM, Demidchik Y, Nishihara E, Hirokawa M, Miyauchi A, Rubanovich AV, Matsuda F, Yamashita S, Saenko VA. Genotype Analyses in the Japanese and Belarusian Populations Reveal Independent Effects of rs965513 and rs1867277 but Do Not Support the Role of FOXE1 Polyalanine Tract Length in Conferring Risk for Papillary Thyroid Carcinoma. Thyroid 2017; 27:224-235. [PMID: 27824288 DOI: 10.1089/thy.2015.0541] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Several functional single-nucleotide polymorphisms (SNPs) at the FOXE1 locus on chromosome 9q22.33 have been associated with the risk for papillary thyroid carcinoma (PTC). This study set out to elucidate whether their effects are independent, using genotyping results in populations of Asian and European descent. METHODS SNPs rs965513 and rs1867277 and a polymorphic region determining the length of the FOXE1 polyalanine (poly-Ala) tract were genotyped in 501 patients with PTC and 748 healthy individuals from Japan, and in 660 patients and 820 population controls from Belarus. Functional analysis of transactivation activities of FOXE1 isoforms with varying number of alanine repeats was performed by a Dual-Luciferase® Assay. RESULTS All three polymorphisms were significantly associated with PTC in both populations on univariate analysis. However, conditional analysis revealed independent effects of rs965513 and rs1867277 SNPs but not of the FOXE1 poly-Ala polymorphism. The independent effect of the lead rs965513 SNP was observed in both populations, while that of rs1867277 was only identified in the Japanese population, in which linkage disequilibrium between the three polymorphisms is markedly weaker. Despite the strong decrease in transcriptional activity with increasing FOXE1 poly-Ala tract length, no difference in transactivation potential of the FOXE1 poly-Ala isoforms could be seen after adjustment for the minimal promoter activity in the reporter vectors. Plasmids encoding FOXE1 isoforms of increasing poly-Ala tract length were also found to produce less FOXE1 protein after cell transfection. CONCLUSIONS The functional variants rs965513 and rs1867277 independently contribute to genetic predisposition to PTC, while a contributing role of the FOXE1 poly-Ala polymorphism could not be confirmed.
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Affiliation(s)
- Alyaksandr V Nikitski
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Tatiana I Rogounovitch
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Andrey Bychkov
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Meiko Takahashi
- 2 Center for the Promotion of Interdisciplinary Education and Research, Kyoto University , Kyoto, Japan
| | - Koh-Ichiro Yoshiura
- 3 Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Norisato Mitsutake
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
- 4 Nagasaki University Research Center for Genomic Instability and Carcinogenesis , Nagasaki, Japan
| | - Takahisa Kawaguchi
- 5 Center for Genomic Medicine, Kyoto University Graduate School of Medicine , Kyoto, Japan
| | - Michiko Matsuse
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Valentina M Drozd
- 6 Department of Endocrinology, Belarusian Academy for Postgraduate Education , Minsk, Belarus
| | - Yuri Demidchik
- 7 Department of Oncology, Belarusian Academy for Postgraduate Education , Minsk, Belarus
| | | | | | | | - Alexander V Rubanovich
- 9 Ecological Genetics Laboratory, Vavilov Institute of General Genetics, Russian Academy of Sciences , Moscow, Russia
- 10 Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Fumihiko Matsuda
- 5 Center for Genomic Medicine, Kyoto University Graduate School of Medicine , Kyoto, Japan
| | - Shunichi Yamashita
- 1 Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
- 10 Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
| | - Vladimir A Saenko
- 10 Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University , Nagasaki, Japan
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31
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Vega IE. EFhd2, a Protein Linked to Alzheimer's Disease and Other Neurological Disorders. Front Neurosci 2016; 10:150. [PMID: 27064956 PMCID: PMC4814571 DOI: 10.3389/fnins.2016.00150] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/21/2016] [Indexed: 01/20/2023] Open
Abstract
EFhd2 is a conserved calcium binding protein linked to different neurological disorders and types of cancer. Although, EFhd2 is more abundant in neurons, it is also found in other cell types. The physiological function of this novel protein is still unclear, but it has been shown in vitro to play a role in calcium signaling, apoptosis, actin cytoskeleton, and regulation of synapse formation. Recently, EFhd2 was shown to promote cell motility by modulating the activity of Rac1, Cdc42, and RhoA. Although, EFhd2's role in promoting cell invasion and metastasis is of great interest in cancer biology, this review focusses on the evidence that links EFhd2 to Alzheimer's disease (AD) and other neurological disorders. Altered expression of EFhd2 has been documented in AD, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, and schizophrenia, indicating that Efhd2 gene expression is regulated in response to neuropathological processes. However, the specific role that EFhd2 plays in the pathophysiology of neurological disorders is still poorly understood. Recent studies demonstrated that EFhd2 has structural characteristics similar to amyloid proteins found in neurological disorders. Moreover, EFhd2 co-aggregates and interacts with known neuropathological proteins, such as tau, C9orf72, and Lrrk2. These results suggest that EFhd2 may play an important role in the pathophysiology of neurodegenerative diseases. Therefore, the understanding of EFhd2's role in health and disease could lead to decipher molecular mechanisms that become activated in response to neuronal stress and degeneration.
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Affiliation(s)
- Irving E Vega
- Department of Translational Science and Molecular Medicine, College of Human Medicine, Michigan State University Grand Rapids, MI, USA
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32
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Yonashiro R, Tahara EB, Bengtson MH, Khokhrina M, Lorenz H, Chen KC, Kigoshi-Tansho Y, Savas JN, Yates JR, Kay SA, Craig EA, Mogk A, Bukau B, Joazeiro CAP. The Rqc2/Tae2 subunit of the ribosome-associated quality control (RQC) complex marks ribosome-stalled nascent polypeptide chains for aggregation. eLife 2016; 5:e11794. [PMID: 26943317 PMCID: PMC4805532 DOI: 10.7554/elife.11794] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 03/03/2016] [Indexed: 12/24/2022] Open
Abstract
Ribosome stalling during translation can potentially be harmful, and is surveyed by a conserved quality control pathway that targets the associated mRNA and nascent polypeptide chain (NC). In this pathway, the ribosome-associated quality control (RQC) complex promotes the ubiquitylation and degradation of NCs remaining stalled in the 60S subunit. NC stalling is recognized by the Rqc2/Tae2 RQC subunit, which also stabilizes binding of the E3 ligase, Listerin/Ltn1. Additionally, Rqc2 modifies stalled NCs with a carboxy-terminal, Ala- and Thr-containing extension—the 'CAT tail'. However, the function of CAT tails and fate of CAT tail-modified ('CATylated') NCs has remained unknown. Here we show that CATylation mediates formation of detergent-insoluble NC aggregates. CATylation and aggregation of NCs could be observed either by inactivating Ltn1 or by analyzing NCs with limited ubiquitylation potential, suggesting that inefficient targeting by Ltn1 favors the Rqc2-mediated reaction. These findings uncover a translational stalling-dependent protein aggregation mechanism, and provide evidence that proteins can become specifically marked for aggregation. DOI:http://dx.doi.org/10.7554/eLife.11794.001 Cells use molecular machines called ribosomes to build proteins by connecting amino acids – the building blocks of proteins – together in a particular sequence. The chain of amino acids gradually lengthens as the protein forms, yet remains attached to the ribosome until the protein is complete. While this process is underway, cells can check that a newly forming chain is not abnormal or damaged. If it is, a cell then essentially ‘decides’ on whether to correct or eliminate it. Such protein quality control processes are important for ensuring the health and fitness of cells and organisms. Recently, a new protein quality control mechanism was discovered that senses when a ribosome becomes jammed as it produces a new protein. This mechanism recycles the ribosome so it can make more new proteins. It also disposes of the stalled protein using a cell complex, called the ribosome-associated quality control complex, which is found in all eukaryotic organisms including yeast and humans. This protein complex consists of three subunits; one of which, called Rcq2, tags ribosome-stalled proteins with a “tail” that contains the amino acids alanine and threonine. However, the purpose of this tag was not clear. Yonashiro, Tahara et al. now show that the tagging of ribosome-stalled proteins by Rqc2 in yeast cells induces the tagged proteins to clump together. This clumping probably prevents these proteins from inadvertently interfering with other molecules or processes within the cell. The formation of these clumps also correlates with the activation of a stress response in the cell, indicating that these clumps create a signal that prompts the cell to protect itself in response to the accumulation of more abnormal proteins. Mutations in one subunit of the ribosome-associated quality control complex in mice cause a condition that resembles a neurological disease in humans, called amyotrophic lateral sclerosis or ALS for short. A future challenge is therefore to understand how much Rqc2-mediated tagging and clumping of ribosome-stalled protein has a role in this and other neurodegenerative diseases. DOI:http://dx.doi.org/10.7554/eLife.11794.002
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Affiliation(s)
- Ryo Yonashiro
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Erich B Tahara
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Mario H Bengtson
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Maria Khokhrina
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Holger Lorenz
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Kai-Chun Chen
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Yu Kigoshi-Tansho
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Jeffrey N Savas
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Steve A Kay
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States
| | - Elizabeth A Craig
- Department of Biochemistry, University of Wisconsin - Madison, Madison, United States
| | - Axel Mogk
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Bernd Bukau
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Claudio A P Joazeiro
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, United States.,Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum-ZMBH Alliance, Heidelberg, Germany
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33
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Engineered Nucleases and Trinucleotide Repeat Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016. [DOI: 10.1007/978-1-4939-3509-3_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Vanhalle M, Corneillie S, Smet M, Van Puyvelde P, Goderis B. Poly(alanine): Structure and Stability of the d and l-Enantiomers. Biomacromolecules 2015; 17:183-91. [DOI: 10.1021/acs.biomac.5b01301] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maja Vanhalle
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Stijn Corneillie
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Mario Smet
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Peter Van Puyvelde
- Soft
Matter, Applied Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, Leuven, 3001, Belgium
| | - Bart Goderis
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
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35
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Polling S, Ormsby AR, Wood RJ, Lee K, Shoubridge C, Hughes JN, Thomas PQ, Griffin MDW, Hill AF, Bowden Q, Böcking T, Hatters DM. Polyalanine expansions drive a shift into α-helical clusters without amyloid-fibril formation. Nat Struct Mol Biol 2015; 22:1008-15. [DOI: 10.1038/nsmb.3127] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 10/20/2015] [Indexed: 12/17/2022]
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36
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Gómez-Sicilia À, Sikora M, Cieplak M, Carrión-Vázquez M. An Exploration of the Universe of Polyglutamine Structures. PLoS Comput Biol 2015; 11:e1004541. [PMID: 26495838 PMCID: PMC4619799 DOI: 10.1371/journal.pcbi.1004541] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/08/2015] [Indexed: 12/02/2022] Open
Abstract
Deposits of misfolded proteins in the human brain are associated with the development of many neurodegenerative diseases. Recent studies show that these proteins have common traits even at the monomer level. Among them, a polyglutamine region that is present in huntingtin is known to exhibit a correlation between the length of the chain and the severity as well as the earliness of the onset of Huntington disease. Here, we apply bias exchange molecular dynamics to generate structures of polyglutamine expansions of several lengths and characterize the resulting independent conformations. We compare the properties of these conformations to those of the standard proteins, as well as to other homopolymeric tracts. We find that, similar to the previously studied polyvaline chains, the set of possible transient folds is much broader than the set of known-to-date folds, although the conformations have different structures. We show that the mechanical stability is not related to any simple geometrical characteristics of the structures. We demonstrate that long polyglutamine expansions result in higher mechanical stability than the shorter ones. They also have a longer life span and are substantially more prone to form knotted structures. The knotted region has an average length of 35 residues, similar to the typical threshold for most polyglutamine-related diseases. Similarly, changes in shape and mechanical stability appear once the total length of the peptide exceeds this threshold of 35 glutamine residues. We suggest that knotted conformers may also harm the cellular machinery and thus lead to disease. Misfolding and aggregation of several proteins are known to be related to neurodegenerative diseases. Among them, polyglutamine expansions are known to be responsible for at least 9 diseases, including Huntington. Nonetheless, the structural properties of these intrinsically disordered proteins are difficult to study using classical techniques because of their rapid fluctuations that result in high conformational polymorphism. Here, we use molecular dynamics simulations to study polyglutamines of different chain lengths, starting with short non-pathogenic ones, and study the independent structures they are able to form. We characterize all structures by their geometrical properties, connectivity, putative mechanical stability and residence time (life span). Similar to the findings of a previous study with polyvalines, only some of the conformers are similar to those found in natural globular proteins. Moreover, we find structures that contain knots in both polyglutamine and polyvaline 60-mers, although the former contains many more knotted conformers than the latter. We suggest that these knotted conformers may impair the cell machinery for degradation and eventually lead to toxicity.
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Affiliation(s)
- Àngel Gómez-Sicilia
- Intituto Cajal/CSIC, Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia),Madrid, Spain
| | - Mateusz Sikora
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Mariano Carrión-Vázquez
- Intituto Cajal/CSIC, Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia),Madrid, Spain
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Vest KE, Apponi LH, Banerjee A, Pavlath GK, Corbett AH. An Antibody to Detect Alanine-Expanded PABPN1: A New Tool to Study Oculopharyngeal Muscular Dystrophy. J Neuromuscul Dis 2015; 2:439-446. [PMID: 27858752 PMCID: PMC5207656 DOI: 10.3233/jnd-150111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Oculopharyngeal muscular dystrophy (OPMD), a late onset disorder affecting specific skeletal muscles, is caused by a (GCG)n expansion mutation in the gene encoding the mRNA processing protein, polyadenylate binding protein nuclear 1 (PABPN1). The expansion in PABPN1 leads to an increase in a stretch of N-terminal alanine residues in the PABPN1 protein from the normal 10 to 12-18. Given this modest change, detection of mutant protein has not been possible without the use of tagged constructs. OBJECTIVE We sought to generate a polyclonal antibody that recognizes alanine-expanded but not wild type PABPN1 with the goal of making possible analysis of expression and localization of alanine-expanded PABPN1. METHODS We immunized rabbits with a GST-tagged alanine peptide and tested the resulting serum against alanine-expanded PABPN1 expressed in cell culture as well as in animal models of OPMD. RESULTS The resulting α-alanine antibody detected PABPN1 proteins that contained 14 or more alanine residues. Importantly, the α-alanine antibody could be used to detect alanine-expanded PABPN1 in muscles from either a mouse or Drosophila model of OPMD. CONCLUSIONS This α-alanine antibody provides a new tool that will allow for more in-depth study of how alanine expansion affects aggregation, localization, and steady-state levels of alanine-expanded PABPN1 levels in vivo, providing new insight into the molecular mechanisms underlying OPMD.
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Affiliation(s)
- Katherine E Vest
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.,Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Luciano H Apponi
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA.,Dicerna Pharmaceuticals, Inc., Cambridge, MA, USA
| | - Ayan Banerjee
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Grace K Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
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Shibata A, Machida J, Yamaguchi S, Kimura M, Tatematsu T, Miyachi H, Matsushita M, Kitoh H, Ishiguro N, Nakayama A, Higashi Y, Shimozato K, Tokita Y. Characterisation of novel RUNX2 mutation with alanine tract expansion from Japanese cleidocranial dysplasia patient. Mutagenesis 2015. [PMID: 26220009 DOI: 10.1093/mutage/gev057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cleidocranial dysplasia (CCD; MIM 119600) is an autosomal dominant skeletal dysplasia characterised by hypopalstic and/or aplastic clavicles, midface hypoplasia, absent or delayed closure of cranial sutures, moderately short stature, delayed eruption of permanent dentition and supernumerary teeth. The molecular pathogenesis can be explained in about two-thirds of CCD patients by haploinsufficiency of the RUNX2 gene. In our current study, we identified a novel and rare variant of the RUNX2 gene (c.181_189dupGCGGCGGCT) in a Japanese patient with phenotypic features of CCD. The insertion led an alanine tripeptide expansion (+3Ala) in the polyalanine tract. To date, a RUNX2 variant with alanine decapeptide expansion (+10Ala) is the only example of a causative variant of RUNX2 with polyalanine tract expansion to be reported, whilst RUNX2 (+1Ala) has been isolated from the healthy population. Thus, precise analyses of the RUNX2 (+3Ala) variant were needed to clarify whether the tripeptide expanded RUNX2 is a second disease-causing mutant with alanine tract expansion. We therefore investigated the biochemical properties of the mutant RUNX2 (+3Ala), which contains 20 alanine residues in the polyalanine tract. When transfected in COS7 cells, RUNX2 (+3Ala) formed intracellular ubiquitinated aggregates after 24h, and exerted a dominant negative effect in vitro. At 24h after gene transfection, whereas slight reduction was observed in RUNX2 (+10Ala), all of these mutants significantly activated osteoblast-specific element-2, a cis-acting sequence in the promoter of the RUNX2 target gene osteocalcin. The aggregation growth of RUNX2 (+3Ala) was clearly lower and slower than that of RUNX2 (+10Ala). Furthermore, we investigated several other RUNX2 variants with various alanine tract lengths, and found that the threshold for aggregation may be RUNX2 (+3Ala). We conclude that RUNX2 (+3Ala) is the cause of CCD in our current case, and that the accumulation of intracellular aggregates in vitro is related to the length of the alanine tract.
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Affiliation(s)
- Akio Shibata
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai 480-0392, Japan, Department of Oral and Maxillofacial Surgery, Ogaki Municipal Hospital, Ogaki 503-0864, Japan
| | - Junichiro Machida
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Oral and Maxillofacial Surgery, Toyota Memorial Hospital, Toyota 471-0821, Japan
| | - Seishi Yamaguchi
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Dentistry and Oral Surgery, Aichi Children's Health and Medical Center, Obu 474-8710, Japan
| | - Masashi Kimura
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Oral and Maxillofacial Surgery, Ogaki Municipal Hospital, Ogaki 503-0864, Japan
| | - Tadashi Tatematsu
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai 480-0392, Japan
| | - Hitoshi Miyachi
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan
| | - Masaki Matsushita
- Department of Orthopaedic Surgery, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Aichi, Japan
| | - Hiroshi Kitoh
- Department of Orthopaedic Surgery, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Aichi, Japan
| | - Naoki Ishiguro
- Department of Orthopaedic Surgery, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Aichi, Japan
| | - Atsuo Nakayama
- Department of Embryology, Institute for Developmental Research, Aichi Human Service Center, Kasugai 480-0392, Japan
| | - Yujiro Higashi
- Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai 480-0392, Japan
| | - Kazuo Shimozato
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan
| | - Yoshihito Tokita
- Department of Maxillofacial Surgery, Aichi-Gakuin University School of Dentistry, Nagoya 464-8651, Japan, Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai 480-0392, Japan,
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Chen YC, Auer-Grumbach M, Matsukawa S, Zitzelsberger M, Themistocleous AC, Strom TM, Samara C, Moore AW, Cho LTY, Young GT, Weiss C, Schabhüttl M, Stucka R, Schmid AB, Parman Y, Graul-Neumann L, Heinritz W, Passarge E, Watson RM, Hertz JM, Moog U, Baumgartner M, Valente EM, Pereira D, Restrepo CM, Katona I, Dusl M, Stendel C, Wieland T, Stafford F, Reimann F, von Au K, Finke C, Willems PJ, Nahorski MS, Shaikh SS, Carvalho OP, Nicholas AK, Karbani G, McAleer MA, Cilio MR, McHugh JC, Murphy SM, Irvine AD, Jensen UB, Windhager R, Weis J, Bergmann C, Rautenstrauss B, Baets J, De Jonghe P, Reilly MM, Kropatsch R, Kurth I, Chrast R, Michiue T, Bennett DLH, Woods CG, Senderek J. Transcriptional regulator PRDM12 is essential for human pain perception. Nat Genet 2015; 47:803-8. [PMID: 26005867 DOI: 10.1038/ng.3308] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/27/2015] [Indexed: 12/12/2022]
Abstract
Pain perception has evolved as a warning mechanism to alert organisms to tissue damage and dangerous environments. In humans, however, undesirable, excessive or chronic pain is a common and major societal burden for which available medical treatments are currently suboptimal. New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. Prdm proteins are a family of epigenetic regulators that control neural specification and neurogenesis. We determined that Prdm12 is expressed in nociceptors and their progenitors and participates in the development of sensory neurons in Xenopus embryos. Moreover, CIP-associated mutants abrogate the histone-modifying potential associated with wild-type Prdm12. Prdm12 emerges as a key factor in the orchestration of sensory neurogenesis and may hold promise as a target for new pain therapeutics.
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Affiliation(s)
- Ya-Chun Chen
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Shinya Matsukawa
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
| | | | - Andreas C Themistocleous
- 1] Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. [2] Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tim M Strom
- 1] Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany. [2] Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Chrysanthi Samara
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Adrian W Moore
- Disease Mechanism Research Core, RIKEN Brain Science Institute, Saitama, Japan
| | | | | | - Caecilia Weiss
- Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany
| | - Maria Schabhüttl
- Department of Orthopaedics, Medical University Vienna, Vienna, Austria
| | - Rolf Stucka
- Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany
| | - Annina B Schmid
- 1] Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. [2] School of Health and Rehabilitation Sciences, The University of Queensland, St. Lucia, Australia
| | - Yesim Parman
- Department of Neurology, Istanbul University, Istanbul, Turkey
| | - Luitgard Graul-Neumann
- Ambulantes Gesundheitszentrum der Charité Campus Virchow (Humangenetik), Universitätsmedizin Berlin, Berlin, Germany
| | - Wolfram Heinritz
- 1] Praxis für Humangenetik Cottbus, Cottbus, Germany. [2] Institut für Humangenetik, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Eberhard Passarge
- 1] Institut für Humangenetik, Universitätsklinikum Leipzig, Leipzig, Germany. [2] Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
| | - Rosemarie M Watson
- Department of Dermatology, Our Lady's Children's Hospital, Dublin, Ireland
| | - Jens Michael Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Ute Moog
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Manuela Baumgartner
- Neuropädiatrische Ambulanz, Krankenhaus der Barmherzigen Schwestern Linz, Linz, Austria
| | - Enza Maria Valente
- Neurogenetics Unit, Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Diego Pereira
- Departamento de Cirugía Plástica, Hospital Infantil Universitario de San José, Bogotá, Colombia
| | | | - Istvan Katona
- Institut für Neuropathologie, Uniklinik RWTH Aachen, Aachen, Germany
| | - Marina Dusl
- Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany
| | - Claudia Stendel
- 1] Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany. [2] German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Thomas Wieland
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Fay Stafford
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Department of Clinical Biochemistry, University of Cambridge, Cambridge, UK
| | - Katja von Au
- SPZ Neuropädiatrie Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Christian Finke
- CharitéCentrum für Zahn-, Mund- und Kieferheilkunde, Arbeitsbereich Kinderzahnmedizin, Universitätsmedizin Berlin, Berlin, Germany
| | | | - Michael S Nahorski
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Samiha S Shaikh
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Ofélia P Carvalho
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Adeline K Nicholas
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Gulshan Karbani
- Yorkshire Regional Genetics Service, Chapel Allerton Hospital, Leeds, UK
| | - Maeve A McAleer
- Department of Dermatology, Our Lady's Children's Hospital, Dublin, Ireland
| | - Maria Roberta Cilio
- 1] Department of Neurology, University of California San Francisco, San Francisco, California, USA. [2] Department of Neuroscience, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
| | - John C McHugh
- Department of Neurology and Neurophysiology, Our Lady's Children's Hospital, Dublin, Ireland
| | - Sinead M Murphy
- 1] Department of Neurology, Adelaide &Meath Hospital, Dublin, Ireland. [2] Academic Unit of Neurology, Trinity College, Dublin, Ireland
| | - Alan D Irvine
- 1] Department of Dermatology, Our Lady's Children's Hospital, Dublin, Ireland. [2] Clinical Medicine, Trinity College, Dublin, Ireland
| | - Uffe Birk Jensen
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Joachim Weis
- Institut für Neuropathologie, Uniklinik RWTH Aachen, Aachen, Germany
| | - Carsten Bergmann
- 1] Center for Human Genetics, Bioscientia, Ingelheim, Germany. [2] Department of Medicine, Renal Division, Freiburg University Medical Center, Freiburg, Germany. [3] Center for Clinical Research, Freiburg University Medical Center, Freiburg, Germany
| | - Bernd Rautenstrauss
- 1] Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany. [2] Medizinisch Genetisches Zentrum, Munich, Germany
| | - Jonathan Baets
- 1] Neurogenetics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium. [2] Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium. [3] Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Peter De Jonghe
- 1] Neurogenetics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium. [2] Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium. [3] Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, National Hospital for Neurology, London, UK
| | - Regina Kropatsch
- Department of Human Genetics, Ruhr-University Bochum, Bochum, Germany
| | - Ingo Kurth
- Institute of Human Genetics, Jena University Hospital, Jena, Germany
| | - Roman Chrast
- 1] Institute of Human Genetics, Technische Universität München, Munich, Germany. [2] Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden. [3] Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Tatsuo Michiue
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - C Geoffrey Woods
- 1] Department of Medical Genetics, University of Cambridge, Cambridge, UK. [2] Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Jan Senderek
- Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich, Germany
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Schulz JCF, Miettinen MS, Netz RR. Unfolding and folding internal friction of β-hairpins is smaller than that of α-helices. J Phys Chem B 2015; 119:4565-74. [PMID: 25741584 DOI: 10.1021/jp512056k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
By the forced unfolding of polyglutamine and polyalanine homopeptides in competing α-helix and β-hairpin secondary structures, we disentangle equilibrium free energetics from nonequilibrium dissipative effects. We find that α-helices are characterized by larger friction or dissipation upon unfolding, regardless of whether they are free energetically preferred over β-hairpins or not. Our analysis, based on MD simulations for atomistic peptide models with explicit water, suggests that this difference is related to the internal friction and mostly caused by the different number of intrapeptide hydrogen bonds in the α-helix and β-hairpin states.
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Affiliation(s)
| | | | - R R Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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41
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Involvement of non-polyalanine (polyA) residues in aggregation of polyA proteins: Clue for inhibition of aggregation. Comput Biol Chem 2014; 53PB:318-323. [PMID: 25462338 DOI: 10.1016/j.compbiolchem.2014.11.003] [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: 05/01/2014] [Revised: 11/11/2014] [Accepted: 11/11/2014] [Indexed: 11/21/2022]
Abstract
Presence of polyalanine (polyA) stretches in some proteins is found to be associated with their aggregation, which causes disorders in various developmental processes. In this work, inherent propensities towards aggregation of some residues, which are not part of the polyA stretches, have been identified by using the primary sequences of seven polyA proteins with the help of Betascan, PASTA and Tango programs and explored unambiguously. This provides a basis for proposing molecular mechanism of this type of aggregation. Reported suppression of aggregation of polyA proteins by chaperones like HSP40 and HSP70 is substantiated through molecular docking. The hydrophobic residues of identified aggregating region are found to be interacting with hydrophobic surface of chaperones. This suggests a crucial clue for possible way to inhibit the aggregation of such proteins.
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Chang SH, Chang WL, Lu CC, Tarn WY. Alanine repeats influence protein localization in splicing speckles and paraspeckles. Nucleic Acids Res 2014; 42:13788-98. [PMID: 25414336 PMCID: PMC4267627 DOI: 10.1093/nar/gku1159] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mammalian splicing regulatory protein RNA-binding motif protein 4 (RBM4) has an alanine repeat-containing C-terminal domain (CAD) that confers both nuclear- and splicing speckle-targeting activities. Alanine-repeat expansion has pathological potential. Here we show that the alanine-repeat tracts influence the subnuclear targeting properties of the RBM4 CAD in cultured human cells. Notably, truncation of the alanine tracts redistributed a portion of RBM4 to paraspeckles. The alanine-deficient CAD was sufficient for paraspeckle targeting. On the other hand, alanine-repeat expansion reduced the mobility of RBM4 and impaired its splicing activity. We further took advantage of the putative coactivator activator (CoAA)-RBM4 conjoined splicing factor, CoAZ, to investigate the function of the CAD in subnuclear targeting. Transiently expressed CoAZ formed discrete nuclear foci that emerged and subsequently separated-fully or partially-from paraspeckles. Alanine-repeat expansion appeared to prevent CoAZ separation from paraspeckles, resulting in their complete colocalization. CoAZ foci were dynamic but, unlike paraspeckles, were resistant to RNase treatment. Our results indicate that the alanine-rich CAD, in conjunction with its conjoined RNA-binding domain(s), differentially influences the subnuclear localization and biogenesis of RBM4 and CoAZ.
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Affiliation(s)
- Shuo-Hsiu Chang
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Wei-Lun Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chia-Chen Lu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Woan-Yuh Tarn
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Functionally significant, rare transcription factor variants in tetralogy of Fallot. PLoS One 2014; 9:e95453. [PMID: 25093829 PMCID: PMC4122343 DOI: 10.1371/journal.pone.0095453] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 03/27/2014] [Indexed: 01/06/2023] Open
Abstract
Objective Rare variants in certain transcription factors involved in cardiac development cause Mendelian forms of congenital heart disease. The purpose of this study was to systematically assess the frequency of rare transcription factor variants in sporadic patients with the cardiac outflow tract malformation tetralogy of Fallot (TOF). Methods and Results We sequenced the coding, 5′UTR, and 3′UTR regions of twelve transcription factor genes implicated in cardiac outflow tract development (NKX2.5, GATA4, ISL1, TBX20, MEF2C, BOP/SMYD1, HAND2, FOXC1, FOXC2, FOXH, FOXA2 and TBX1) in 93 non-syndromic, non-Mendelian TOF cases. We also analysed Illumina Human 660W-Quad SNP Array data for copy number variants in these genes; none were detected. Four of the rare variants detected have previously been shown to affect transactivation in in vitro reporter assays: FOXC1 p.P297S, FOXC2 p.Q444R, FOXH1 p.S113T and TBX1 p.P43_G61del PPPPRYDPCAAAAPGAPGP. Two further rare variants, HAND2 p.A25_A26insAA and FOXC1 p.G378_G380delGGG, A488_491delAAAA, affected transactivation in in vitro reporter assays. Each of these six functionally significant variants was present in a single patient in the heterozygous state; each of the four for which parental samples were available were maternally inherited. Thus in the 93 TOF cases we identified six functionally significant mutations in the secondary heart field transcriptional network. Significance This study indicates that rare genetic variants in the secondary heart field transcriptional network with functional effects on protein function occur in 3–13% of patients with TOF. This is the first report of a functionally significant HAND2 mutation in a patient with congenital heart disease.
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Deng H, Zheng W, Song Z. Genetics, Molecular Biology, and Phenotypes of X-Linked Epilepsy. Mol Neurobiol 2013; 49:1166-80. [DOI: 10.1007/s12035-013-8589-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 11/05/2013] [Indexed: 11/25/2022]
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Polyalanine tract disorders and neurocognitive phenotypes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 769:185-203. [PMID: 23560312 DOI: 10.1007/978-1-4614-5434-2_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Expansion of polyalanine tracts cause at least 9 inherited human diseases. Eight of these nine diseases are due to expansions in transcription factors and give rise to congenital disorders, many with neurocognitive phenotypes. Disease-causing expansions vary in length dependingupon the gene in question, with the severity of the associated clinical phenotype generally increasing with length of the polyalanine tract. The past decade has seen considerable progress in the understanding on how these mutations may arise and the functional effect of expanded polyalanine tracts on the resulting protein. Despite this progress, the pathogenic mechanism of expanded polyalanine tracts contributing to the associated disease states remains poorly understood. Gaining insights into the mechanisms that underlie the pathogenesis of different expanded polyalanine tract mutations will be a necessary step on the path to the design of potential treatment strategies for the associated diseases.
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Raz V, Butler-Browne G, van Engelen B, Brais B. 191st ENMC International Workshop: Recent advances in oculopharyngeal muscular dystrophy research: From bench to bedside 8-10 June 2012, Naarden, The Netherlands. Neuromuscul Disord 2013; 23:516-23. [DOI: 10.1016/j.nmd.2013.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Indexed: 10/27/2022]
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Buttstedt A, Wostradowski T, Ihling C, Hause G, Sinz A, Schwarz E. Different morphology of amyloid fibrils originating from agitated and non-agitated conditions. Amyloid 2013; 20:86-92. [PMID: 23570235 DOI: 10.3109/13506129.2013.784962] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In vitro amyloid formation has been suggested to be a common property of any polypeptide chain depending on particular environmental conditions although in vivo amyloid fibril formation can be promoted by point mutations or triplet expansions. Here, we explored the influence of agitation on fibril formation of amyloidogenic alanine segments fused to Cold Shock Protein B (CspB) of Bacillus subtilis. While without agitation fibril formation was clearly dependent on the presence of an amyloidogenic alanine segment, fibril formation was independent of the amyloidogenic segment under agitation. Agitation even led to fibrillation of native CspB lacking the amyloidogenic segment. Furthermore, agitation not only influenced the kinetics of fibril formation, but also resulted in completely different fibril morphologies. These results indicate that experimental conditions can alter the region that undergoes a conformational change during in vitro fibrillation. Moreover, the data show that deductions from in vitro assays on in vivo fibril formation mechanisms are afflicted with a certain degree of uncertainty and therefore need to be cautiously discussed.
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Affiliation(s)
- Anja Buttstedt
- Facultatea de Zootehnie şi Biotehnologii, Universitatea de Ştiinţe Agricole şi Medicină Veterinară, Calea Mănăştur 3-5, 400372 Cluj-Napoca, Romania.
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Acosta YF, Rodríguez Cruz EN, Vaquer ADC, Vega IE. Functional and structural analysis of the conserved EFhd2 protein. Protein Pept Lett 2013; 20:573-83. [PMID: 22973849 PMCID: PMC3633529 DOI: 10.2174/0929866511320050011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 08/25/2012] [Accepted: 08/26/2012] [Indexed: 01/14/2023]
Abstract
EFhd2 is a novel protein conserved from C. elegans to H. sapiens. This novel protein was originally identified in cells of the immune and central nervous systems. However, it is most abundant in the central nervous system, where it has been found associated with pathological forms of the microtubule-associated protein tau. The physiological or pathological roles of EFhd2 are poorly understood. In this study, a functional and structural analysis was carried to characterize the molecular requirements for EFhd2's calcium binding activity. The results showed that mutations of a conserved aspartate on either EF-hand motif disrupted the calcium binding activity, indicating that these motifs work in pair as a functional calcium binding domain. Furthermore, characterization of an identified single-nucleotide polymorphisms (SNP) that introduced a missense mutation indicates the importance of a conserved phenylalanine on EFhd2 calcium binding activity. Structural analysis revealed that EFhd2 is predominantly composed of alpha helix and random coil structures and that this novel protein is thermostable. EFhd2's thermo stability depends on its N-terminus. In the absence of the N-terminus, calcium binding restored EFhd2's thermal stability. Overall, these studies contribute to our understanding on EFhd2 functional and structural properties, and introduce it into the family of canonical EF-hand domain containing proteins.
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Affiliation(s)
- Yancy Ferrer Acosta
- Department of Biology, University of Puerto Rico-Río Piedras Campus, San Juan, PR 00931
| | - Eva N. Rodríguez Cruz
- Department of Biology, University of Puerto Rico-Río Piedras Campus, San Juan, PR 00931
| | - Ana del C. Vaquer
- Department of Biology, University of Puerto Rico-Río Piedras Campus, San Juan, PR 00931
| | - Irving E. Vega
- Department of Biology, University of Puerto Rico-Río Piedras Campus, San Juan, PR 00931
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Mechanistic insight into the pathology of polyalanine expansion disorders revealed by a mouse model for X linked hypopituitarism. PLoS Genet 2013; 9:e1003290. [PMID: 23505376 PMCID: PMC3591313 DOI: 10.1371/journal.pgen.1003290] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 12/16/2012] [Indexed: 11/19/2022] Open
Abstract
Polyalanine expansions in transcription factors have been associated with eight distinct congenital human diseases. It is thought that in each case the polyalanine expansion causes misfolding of the protein that abrogates protein function. Misfolded proteins form aggregates when expressed in vitro; however, it is less clear whether aggregation is of relevance to these diseases in vivo. To investigate this issue, we used targeted mutagenesis of embryonic stem (ES) cells to generate mice with a polyalanine expansion mutation in Sox3 (Sox3-26ala) that is associated with X-linked Hypopituitarism (XH) in humans. By investigating both ES cells and chimeric mice, we show that endogenous polyalanine expanded SOX3 does not form protein aggregates in vivo but rather is present at dramatically reduced levels within the nucleus of mutant cells. Importantly, the residual mutant protein of chimeric embryos is able to rescue a block in gastrulation but is not sufficient for normal development of the hypothalamus, a region that is functionally compromised in Sox3 null embryos and individuals with XH. Together, these data provide the first definitive example of a disease-relevant PA mutant protein that is both nuclear and functional, thereby manifesting as a partial loss-of-function allele.
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Hughes JN, Thomas PQ. Molecular pathology of polyalanine expansion disorders: new perspectives from mouse models. Methods Mol Biol 2013; 1017:135-51. [PMID: 23719913 DOI: 10.1007/978-1-62703-438-8_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Disease-causing polyalanine (PA) expansion mutations have been identified in nine genes, eight of which encode transcription factors (TFs) with important roles in development. In vitro and cell overexpression studies have shown that expanded PA tracts result in protein misfolding and the formation of aggregates. This feature of PA proteins is reminiscent of the related polyglutamine (PQ) disease proteins, which have been shown to cause disease via a gain-of-function (GOF) mechanism. However, in sharp contrast to PQ disorders, the disease phenotypes associated with PA mutations are more consistent with a LOF and/or mild GOF mechanism, suggesting that their molecular pathology is inherently different to PQ disorders. Elucidating the cellular impact of PA mutations in vivo has been difficult to address as, unlike the late-onset polyglutamine disorders, all PA disorders associated with TF gene mutations are congenital. However, in recent years, significant advances have been made through the analysis of engineered (knock-in) and spontaneous PA mouse models. Here we review these recent findings and propose an updated model of the molecular and cellular mechanism of PA disorders that incorporates both LOF and GOF features.
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Affiliation(s)
- James N Hughes
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
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