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Shi X, Yao J, Huang Y, Wang Y, Jiang X, Wang Z, Zhang M, Zhang Y, Liu X. Hhatl ameliorates endoplasmic reticulum stress through autophagy by associating with LC3. J Biol Chem 2024; 300:107335. [PMID: 38705394 PMCID: PMC11143907 DOI: 10.1016/j.jbc.2024.107335] [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: 04/03/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
Endoplasmic reticulum (ER) stress, a common cellular stress response induced by various factors that interfere with cellular homeostasis, may trigger cell apoptosis. Autophagy is an important and conserved mechanism for eliminating aggregated proteins and maintaining protein stability of cells, which is closely associated with ER stress and ER stress-induced apoptosis. In this paper, we report for the first time that Hhatl, an ER-resident protein, is downregulated in response to ER stress. Hhatl overexpression alleviated ER stress and ER stress induced apoptosis in cells treated with tunicamycin or thapsigargin, whereas Hhatl knockdown exacerbated ER stress and apoptosis. Further study showed that Hhatl attenuates ER stress by promoting autophagic flux. Mechanistically, we found that Hhatl promotes autophagy by associating with autophagic protein LC3 (microtubule-associated protein 1A/1B-light chain 3) via the conserved LC3-interacting region motif. Noticeably, the LC3-interacting region motif was essential for Hhatl-regulated promotion of autophagy and reduction of ER stress. These findings demonstrate that Hhatl ameliorates ER stress via autophagy activation by interacting with LC3, thereby alleviating cellular pressure. The study indicates that pharmacological or genetic regulation of Hhatl-autophagy signaling might be potential for mediating ER stress and related diseases.
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Affiliation(s)
- Xingjuan Shi
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.
| | - Jiayu Yao
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Yexi Huang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Yushan Wang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Xuan Jiang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Ziwen Wang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Mingming Zhang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Yu Zhang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Xiangdong Liu
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
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Zhang T, Cui S, Xiong X, Liu Y, Cao Q, Xia XG, Zhou H. PIH1D3-knockout rats exhibit full ciliopathy features and dysfunctional pre-assembly and loading of dynein arms in motile cilia. Front Cell Dev Biol 2023; 11:1282787. [PMID: 37900281 PMCID: PMC10601634 DOI: 10.3389/fcell.2023.1282787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 09/27/2023] [Indexed: 10/31/2023] Open
Abstract
Background: Recessive mutation of the X-linked gene, PIH1 domain-containing protein 3 (PIH1D3), causes familial ciliopathy. PIH1D3 deficiency is associated with the defects of dynein arms in cilia, but how PIH1D3 specifically affects the structure and function of dynein arms is not understood yet. To gain insights into the underlying mechanisms of the disease, it is crucial to create a reliable animal model. In humans, rats, and mice, one copy of the PIH1D3 gene is located on the X chromosome. Interestingly, mice have an additional, intronless copy of the Pih1d3 gene on chromosome 1. To develop an accurate disease model, it is best to manipulate the X-linked PIH1D3 gene, which contains essential regulatory sequences within the introns for precise gene expression. This study aimed to develop a tailored rat model for PIH1D3-associated ciliopathy with the ultimate goal of uncovering the intricate molecular mechanisms responsible for ciliary defects in the disease. Methods: Novel Pih1d3-knockout (KO) rats were created by using TALEN-mediated non-homologous DNA recombination within fertilized rat eggs and, subsequently, underwent a comprehensive characterization through a battery of behavioral and pathological assays. A series of biochemical and histological analyses were conducted to elucidate the identity of protein partners that interact with PIH1D3, thus shedding light on the intricate molecular mechanisms involved in this context. Results: PIH1D3-KO rats reproduced the cardinal features of ciliopathy including situs inversus, defects in spermatocyte survival and mucociliary clearance, and perinatal hydrocephalus. We revealed the novel function of PIH1D3 in cerebrospinal fluid circulation and elucidated the mechanism by which PIH1D3 deficiency caused communicating hydrocephalus. PIH1D3 interacted with the proteins required for the pre-assembly and uploading of outer (ODA) and inner dynein arms (IDA), regulating the integrity of dynein arm structure and function in cilia. Conclusion: PIH1D3-KO rats faithfully reproduced the cardinal features of ciliopathy associated with PIH1D3 deficiency. PIH1D3 interacted with the proteins responsible for the pre-assembly and uploading of dynein arms in cilia, and its deficiency led to dysfunctional cilia and, thus, to ciliopathy by affecting the pre-assembly and uploading of dynein arms. The resultant rat model is a valuable tool for the mechanistic study of PIH1D3-caused diseases.
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Affiliation(s)
- Tingting Zhang
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Shiquan Cui
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Xinrui Xiong
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Ying Liu
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Qilin Cao
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Xu-Gang Xia
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
| | - Hongxia Zhou
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Port St Lucie, FL, United States
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3
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Cui S, Zhang T, Xiong X, Zhao J, Cao Q, Zhou H, Xia XG. Detergent-insoluble PFN1 inoculation expedites disease onset and progression in PFN1 transgenic rats. Front Neurosci 2023; 17:1279259. [PMID: 37817804 PMCID: PMC10560758 DOI: 10.3389/fnins.2023.1279259] [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: 08/17/2023] [Accepted: 09/13/2023] [Indexed: 10/12/2023] Open
Abstract
Accumulating evidence suggests a gain of elusive toxicity in pathogenically mutated PFN1. The prominence of PFN1 aggregates as a pivotal pathological hallmark in PFN1 transgenic rats underscores the crucial involvement of protein aggregation in the initiation and progression of neurodegeneration. Detergent-insoluble materials were extracted from the spinal cords of paralyzed rats afflicted with ALS and were intramuscularly administered to asymptomatic recipient rats expressing mutant PFN1, resulting in an accelerated development of PFN1 inclusions and ALS-like phenotypes. This effect diminished when the extracts derived from wildtype PFN1 transgenic rats were employed, as detergent-insoluble PFN1 was detected exclusively in mutant PFN1 transgenic rats. Consequently, the factor influencing the progression of ALS pathology in recipient rats is likely associated with the presence of detergent-insoluble PFN1 within the extracted materials. Noteworthy is the absence of disease course modification upon administering detergent-insoluble extracts to rats that already displayed PFN1 inclusions, suggesting a seeding rather than augmenting role of such extracts in initiating neuropathological changes. Remarkably, pathogenic PFN1 exhibited an enhanced affinity for the molecular chaperone DNAJB6, leading to the sequestration of DNAJB6 within protein inclusions, thereby depleting its availability for cellular functions. These findings shed light on a novel mechanism that underscores the prion-like characteristics of pathogenic PFN1 in driving neurodegeneration in the context of PFN1-related ALS.
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Affiliation(s)
- Shiquan Cui
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
| | - Tingting Zhang
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
| | - Xinrui Xiong
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
| | - Jihe Zhao
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Qilin Cao
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Florida International University, Miami, FL, United States
| | - Hongxia Zhou
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Florida International University, Miami, FL, United States
| | - Xu-Gang Xia
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
- The Center for Translational Sciences, Florida International University, Miami, FL, United States
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Chu S, Xie X, Payan C, Stochaj U. Valosin containing protein (VCP): initiator, modifier, and potential drug target for neurodegenerative diseases. Mol Neurodegener 2023; 18:52. [PMID: 37545006 PMCID: PMC10405438 DOI: 10.1186/s13024-023-00639-y] [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: 02/20/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023] Open
Abstract
The AAA+ ATPase valosin containing protein (VCP) is essential for cell and organ homeostasis, especially in cells of the nervous system. As part of a large network, VCP collaborates with many cofactors to ensure proteostasis under normal, stress, and disease conditions. A large number of mutations have revealed the importance of VCP for human health. In particular, VCP facilitates the dismantling of protein aggregates and the removal of dysfunctional organelles. These are critical events to prevent malfunction of the brain and other parts of the nervous system. In line with this idea, VCP mutants are linked to the onset and progression of neurodegeneration and other diseases. The intricate molecular mechanisms that connect VCP mutations to distinct brain pathologies continue to be uncovered. Emerging evidence supports the model that VCP controls cellular functions on multiple levels and in a cell type specific fashion. Accordingly, VCP mutants derail cellular homeostasis through several mechanisms that can instigate disease. Our review focuses on the association between VCP malfunction and neurodegeneration. We discuss the latest insights in the field, emphasize open questions, and speculate on the potential of VCP as a drug target for some of the most devastating forms of neurodegeneration.
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Affiliation(s)
- Siwei Chu
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Xinyi Xie
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Carla Payan
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada
| | - Ursula Stochaj
- Department of Physiology, McGill University, Montreal, HG3 1Y6, Canada.
- Quantitative Life Sciences Program, McGill University, Montreal, Canada.
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5
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Scietti L, Forneris F. Modeling of Protein Complexes. Methods Mol Biol 2023; 2627:349-371. [PMID: 36959458 DOI: 10.1007/978-1-0716-2974-1_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
The recent advances in structural biology, combined with continuously increasing computational capabilities and development of advanced softwares, have drastically simplified the workflow for protein homology modeling. Modeling of individual proteins is nowadays quick and straightforward for a large variety of protein targets, thanks to guided pipelines relying on advanced computational tools and user-friendly interfaces, which have extended and promoted the use of modeling also to scientists not focusing on molecular structures of proteins. Nevertheless, construction of models of multi-protein complexes remains quite challenging for the non-experts, often due to the usage of specific procedures depending on the system under investigation and the need for experimental validation approaches to strengthen the generated output.In this chapter, we provide a brief overview of the approaches enabling generation of multi-protein complex models starting from homology models of individual protein components. Using real-life examples, we include two examples to guide the reader in the generation of homomeric and heteromeric protein models.
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Affiliation(s)
- Luigi Scietti
- Department of Biology and Biotechnology, The Armenise-Harvard Laboratory of Structural Biology, University of Pavia, Pavia, Italy.
| | - Federico Forneris
- Department of Biology and Biotechnology, The Armenise-Harvard Laboratory of Structural Biology, University of Pavia, Pavia, Italy.
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Geng T, Yang D, Lin T, Cahoon JG, Wang P. UBXN3B Controls Immunopathogenesis of Arthritogenic Alphaviruses by Maintaining Hematopoietic Homeostasis. mBio 2022; 13:e0268722. [PMID: 36377866 PMCID: PMC9765034 DOI: 10.1128/mbio.02687-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022] Open
Abstract
Ubiquitin regulatory X domain-containing proteins (UBXN) might be involved in diverse cellular processes. However, their in vivo physiological functions remain largely elusive. We recently showed that UBXN3B positively regulated stimulator-of-interferon-genes (STING)-mediated innate immune responses to DNA viruses. Herein, we reported the essential role of UBXN3B in the control of infection and immunopathogenesis of two arthritogenic RNA viruses, Chikungunya (CHIKV) and O'nyong'nyong (ONNV) viruses. Ubxn3b deficient (Ubxn3b-/-) mice presented higher viral loads, more severe foot swelling and immune infiltrates, and slower clearance of viruses and resolution of inflammation than the Ubxn3b+/+ littermates. While the serum cytokine levels were intact, the virus-specific immunoglobulin G and neutralizing antibody levels were lower in the Ubxn3b-/- mice. The Ubxn3b-/- mice had more neutrophils and macrophages, but much fewer B cells in the ipsilateral feet. Of note, this immune dysregulation was also observed in the spleens and blood of uninfected Ubxn3b-/- mice. UBXN3B restricted CHIKV replication in a cell-intrinsic manner but independent of type I IFN signaling. These results demonstrated a dual role of UBXN3B in the maintenance of immune homeostasis and control of RNA virus replication. IMPORTANCE The human genome encodes 13 ubiquitin regulatory X (UBX) domain-containing proteins (UBXN) that might participate in diverse cellular processes. However, their in vivo physiological functions remain largely elusive. Herein, we reported an essential role of UBXN3B in the control of infection and immunopathogenesis of arthritogenic alphaviruses, including Chikungunya virus (CHIKV), which causes acute and chronic crippling arthralgia, long-term neurological disorders, and poses a significant public health problem in the tropical and subtropical regions worldwide. However, there are no approved vaccines or specific antiviral drugs. This was partly due to a poor understanding of the protective and detrimental immune responses elicited by CHIKV. We showed that UBXN3B was critical for the control of CHIKV replication in a cell-intrinsic manner in the acute phase and persistent immunopathogenesis in the post-viremic stage. Mechanistically, UBXN3B was essential for the maintenance of hematopoietic homeostasis during viral infection and in steady-state.
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Affiliation(s)
- Tingting Geng
- Department of Immunology, School of Medicine, the University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Duomeng Yang
- Department of Immunology, School of Medicine, the University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Tao Lin
- Department of Immunology, School of Medicine, the University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Jason G. Cahoon
- Department of Immunology, School of Medicine, the University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Penghua Wang
- Department of Immunology, School of Medicine, the University of Connecticut Health Center, Farmington, Connecticut, USA
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Kochenova OV, Mukkavalli S, Raman M, Walter JC. Cooperative assembly of p97 complexes involved in replication termination. Nat Commun 2022; 13:6591. [PMID: 36329031 PMCID: PMC9633789 DOI: 10.1038/s41467-022-34210-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
The p97 ATPase extracts polyubiquitylated proteins from diverse cellular structures in preparation for destruction by the proteasome. p97 functions with Ufd1-Npl4 and a variety of UBA-UBX co-factors, but how p97 complexes assemble on ubiquitylated substrates is unclear. To address this, we investigated how p97 disassembles the CMG helicase after it is ubiquitylated during replication termination. We show that p97Ufd1-Npl4 recruitment to CMG requires the UBA-UBX protein Ubxn7, and conversely, stable Ubxn7 binding to CMG requires p97Ufd1-Npl4. This cooperative assembly involves interactions between Ubxn7, p97, Ufd1-Npl4, and ubiquitin. Another p97 co-factor, Faf1, partially compensates for the loss of Ubxn7. Surprisingly, p97Ufd1-Npl4-Ubxn7 and p97Ufd1-Npl4-Faf1 also assemble cooperatively on unanchored ubiquitin chains. We propose that cooperative and substrate-independent recognition of ubiquitin chains allows p97 to recognize an unlimited number of polyubiquitylated proteins while avoiding the formation of partial, inactive complexes.
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Affiliation(s)
- Olga V Kochenova
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Sirisha Mukkavalli
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Malavika Raman
- Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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8
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Lin BC, Higgins NR, Phung TH, Monteiro MJ. UBQLN proteins in health and disease with a focus on UBQLN2 in ALS/FTD. FEBS J 2022; 289:6132-6153. [PMID: 34273246 PMCID: PMC8761781 DOI: 10.1111/febs.16129] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/16/2021] [Indexed: 01/12/2023]
Abstract
Ubiquilin (UBQLN) proteins are a dynamic and versatile family of proteins found in all eukaryotes that function in the regulation of proteostasis. Besides their canonical function as shuttle factors in delivering misfolded proteins to the proteasome and autophagy systems for degradation, there is emerging evidence that UBQLN proteins play broader roles in proteostasis. New information suggests the proteins function as chaperones in protein folding, protecting proteins prior to membrane insertion, and as guardians for mitochondrial protein import. In this review, we describe the evidence for these different roles, highlighting how different domains of the proteins impart these functions. We also describe how changes in the structure and phase separation properties of UBQLNs may regulate their activity and function. Finally, we discuss the pathogenic mechanisms by which mutations in UBQLN2 cause amyotrophic lateral sclerosis and frontotemporal dementia. We describe the animal model systems made for different UBQLN2 mutations and how lessons learnt from these systems provide fundamental insight into the molecular mechanisms by which UBQLN2 mutations drive disease pathogenesis through disturbances in proteostasis.
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Affiliation(s)
- Brian C. Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nicole R. Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Trong H. Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mervyn J. Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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9
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Thakur AK, Luthra-Guptasarma M. Differences in Cellular Clearing Mechanisms of Aggregates of Two Subtypes of HLA-B27. Front Immunol 2022; 12:795053. [PMID: 35082784 PMCID: PMC8785436 DOI: 10.3389/fimmu.2021.795053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/10/2021] [Indexed: 01/08/2023] Open
Abstract
Ankylosing spondylitis (AS) belongs to a group of diseases, called spondyloarthropathies (SpA), that are strongly associated with the genetic marker HLA-B27. AS is characterized by inflammation of joints and primarily affects the spine. Over 160 subtypes of HLA-B27 are known, owing to high polymorphism. Some are strongly associated with disease (e.g., B*2704), whereas others are not (e.g., B*2709). Misfolding of HLA-B27 molecules [as dimers, or as high-molecular-weight (HMW) oligomers] is one of several hypotheses proposed to explain the link between HLA-B27 and AS. Our group has previously established the existence of HMW species of HLA-B27 in AS patients. Still, very little is known about the mechanisms underlying differences in pathogenic outcomes of different HLA-B27 subtypes. We conducted a proteomics-based evaluation of the differential disease association of HLA B*2704 and B*2709, using stable transfectants of genes encoding the two proteins. A clear difference was observed in protein clearance mechanisms: whereas unfolded protein response (UPR), autophagy, and aggresomes were involved in the degradation of B*2704, the endosome–lysosome machinery was primarily involved in B*2709 degradation. These differences offer insights into the differential disease association of B*2704 and B*2709.
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Affiliation(s)
- Amit Kumar Thakur
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Manni Luthra-Guptasarma
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Higgins NR, Greenslade JE, Wu JJ, Miranda E, Galliciotti G, Monteiro MJ. Serpin neuropathology in the P497S UBQLN2 mouse model of ALS/FTD. Brain Pathol 2021; 31:e12948. [PMID: 33780087 PMCID: PMC8387369 DOI: 10.1111/bpa.12948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/17/2021] [Accepted: 03/08/2021] [Indexed: 01/12/2023] Open
Abstract
Accumulating evidence suggests X-linked dominant mutations in UBQLN2 cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD) through both loss- and gain-of-function mechanisms. However, the mechanisms by which the mutations cause disease are still unclear. The goal of the study was to uncover the possible pathomechanism(s) by which UBQLN2 mutations cause ALS/FTD. An analysis of proteomic changes in neuronal tissue was used to identify proteins with altered accumulation in the P497S UBQLN2 transgenic mouse model of ALS/FTD. We then used immunocytochemistry and biochemical techniques to confirm protein changes in the mutant P497S mice. Additionally, we used cell lines inactivated of UBQLN2 expression to determine whether its loss underlies the alteration in the proteins seen in P497S mice. The proteome screen identified a dramatic alteration of serine protease inhibitor (serpin) proteins in the mutant P497S animals. Double immunofluorescent staining of brain and spinal cord tissues of the mutant and control mice revealed an age-dependent change in accumulation of Serpin A1, C1, and I1 in puncta whose staining colocalized with UBQLN2 puncta in the mutant P497S mice. Serpin A1 aggregation in P497S animals was confirmed by biochemical extraction and filter retardation assays. A similar phenomenon of serpin protein aggregation was found in HeLa and NSC34 motor neuron cells with inactivated UBQLN2 expression. We found aberrant aggregation of serpin proteins, particularly Serpin A1, in the brain and spinal cord of the P497S UBQLN2 mouse model of ALS/FTD. Similar aggregation of serpin proteins was found in UBQLN2 knockout cells suggesting that serpin aggregation in the mutant P497S animals may stem from loss of UBQLN2 function. Because serpin aggregation is known to cause disease through both loss- and gain-of-function mechanisms, we speculate that their accumulation in the P497S mouse model of ALS/FTD may contribute to disease pathogenesis through similar mechanism(s).
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Affiliation(s)
- Nicole R. Higgins
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Jessie E. Greenslade
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Josephine J. Wu
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’Pasteur Institute – Cenci Bolognetti FoundationSapienza University of RomeRomeItaly
| | - Giovanna Galliciotti
- Institute of NeuropathologyUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Mervyn J. Monteiro
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
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11
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Gerson JE, Safren N, Fischer S, Patel R, Crowley EV, Welday JP, Windle AK, Barmada S, Paulson HL, Sharkey LM. Ubiquilin-2 differentially regulates polyglutamine disease proteins. Hum Mol Genet 2021; 29:2596-2610. [PMID: 32681165 DOI: 10.1093/hmg/ddaa152] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022] Open
Abstract
Divergent protein context helps explain why polyglutamine expansion diseases differ clinically and pathologically. This heterogeneity may also extend to how polyglutamine disease proteins are handled by cellular pathways of proteostasis. Studies suggest, for example, that the ubiquitin-proteasome shuttle protein Ubiquilin-2 (UBQLN2) selectively interacts with specific polyglutamine disease proteins. Here we employ cellular models, primary neurons and mouse models to investigate the potential differential regulation by UBQLN2 of two polyglutamine disease proteins, huntingtin (HTT) and ataxin-3 (ATXN3). In cells, overexpressed UBQLN2 selectively lowered levels of full-length pathogenic HTT but not of HTT exon 1 fragment or full-length ATXN3. Consistent with these results, UBQLN2 specifically reduced accumulation of aggregated mutant HTT but not mutant ATXN3 in mouse models of Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3), respectively. Normally a cytoplasmic protein, UBQLN2 translocated to the nuclei of neurons in HD mice but not in SCA3 mice. Remarkably, instead of reducing the accumulation of nuclear mutant ATXN3, UBQLN2 induced an accumulation of cytoplasmic ATXN3 aggregates in neurons of SCA3 mice. Together these results reveal a selective action of UBQLN2 toward polyglutamine disease proteins, indicating that polyglutamine expansion alone is insufficient to promote UBQLN2-mediated clearance of this class of disease proteins. Additional factors, including nuclear translocation of UBQLN2, may facilitate its action to clear intranuclear, aggregated disease proteins like HTT.
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Affiliation(s)
- Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ronak Patel
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Jacqueline P Welday
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Alexandra K Windle
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
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12
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Gwon Y, Maxwell BA, Kolaitis RM, Zhang P, Kim HJ, Taylor JP. Ubiquitination of G3BP1 mediates stress granule disassembly in a context-specific manner. Science 2021; 372:eabf6548. [PMID: 34739333 PMCID: PMC8574224 DOI: 10.1126/science.abf6548] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Stress granules are dynamic, reversible condensates composed of RNA and protein that assemble in eukaryotic cells in response to a variety of stressors and are normally disassembled after stress is removed. The composition and assembly of stress granules is well understood, but little is known about the mechanisms that govern disassembly. Impaired disassembly has been implicated in some diseases including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Using cultured human cells, we found that stress granule disassembly was context-dependent: Specifically in the setting of heat shock, disassembly required ubiquitination of G3BP1, the central protein within the stress granule RNA-protein network. We found that ubiquitinated G3BP1 interacted with the endoplasmic reticulum–associated protein FAF2, which engaged the ubiquitin-dependent segregase p97/VCP (valosin-containing protein). Thus, targeting of G3BP1 weakened the stress granule–specific interaction network, resulting in granule disassembly.
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Affiliation(s)
- Youngdae Gwon
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Brian A. Maxwell
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Regina-Maria Kolaitis
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Peipei Zhang
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - J. Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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13
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Lin BC, Phung TH, Higgins NR, Greenslade JE, Prado MA, Finley D, Karbowski M, Polster BM, Monteiro MJ. ALS/FTD mutations in UBQLN2 are linked to mitochondrial dysfunction through loss-of-function in mitochondrial protein import. Hum Mol Genet 2021; 30:1230-1246. [PMID: 33891006 PMCID: PMC8212775 DOI: 10.1093/hmg/ddab116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 01/12/2023] Open
Abstract
UBQLN2 mutations cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD), but the pathogenic mechanisms by which they cause disease remain unclear. Proteomic profiling identified 'mitochondrial proteins' as comprising the largest category of protein changes in the spinal cord (SC) of the P497S UBQLN2 mouse model of ALS/FTD. Immunoblots confirmed P497S animals have global changes in proteins predictive of a severe decline in mitochondrial health, including oxidative phosphorylation (OXPHOS), mitochondrial protein import and network dynamics. Functional studies confirmed mitochondria purified from the SC of P497S animals have age-dependent decline in nearly all steps of OXPHOS. Mitochondria cristae deformities were evident in spinal motor neurons of aged P497S animals. Knockout (KO) of UBQLN2 in HeLa cells resulted in changes in mitochondrial proteins and OXPHOS activity similar to those seen in the SC. KO of UBQLN2 also compromised targeting and processing of the mitochondrial import factor, TIMM44, resulting in accumulation in abnormal foci. The functional OXPHOS deficits and TIMM44-targeting defects were rescued by reexpression of WT UBQLN2 but not by ALS/FTD mutant UBQLN2 proteins. In vitro binding assays revealed ALS/FTD mutant UBQLN2 proteins bind weaker with TIMM44 than WT UBQLN2 protein, suggesting that the loss of UBQLN2 binding may underlie the import and/or delivery defect of TIMM44 to mitochondria. Our studies indicate a potential key pathogenic disturbance in mitochondrial health caused by UBQLN2 mutations.
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Affiliation(s)
- Brian C Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Trong H Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nicole R Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jessie E Greenslade
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mariusz Karbowski
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian M Polster
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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14
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Riley JF, Fioramonti PJ, Rusnock AK, Hehnly H, Castañeda CA. ALS-linked mutations impair UBQLN2 stress-induced biomolecular condensate assembly in cells. J Neurochem 2021; 159:145-155. [PMID: 34129687 DOI: 10.1111/jnc.15453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/30/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
Mutations in Ubiquilin-2 (UBQLN2), a ubiquitin-binding shuttle protein involved in several protein quality control processes, can lead to amyotrophic lateral sclerosis (ALS). We previously found that wild-type UBQLN2 forms dynamic, membraneless biomolecular condensates upon cellular stress, and undergoes liquid-liquid phase separation in vitro. However, the impact of ALS-linked mutations on UBQLN2 condensate formation in cells is unknown. Here, we employ live-cell imaging and photokinetic analysis to investigate how five patient-derived ALS-linked mutations in UBQLN2 impact stress-induced UBQLN2 condensate assembly and condensate material properties. Both wild-type and mutant UBQLN2 condensates are generally cytoplasmic and liquid-like. However, cells transfected with mutant UBQLN2 contain fewer stress-induced UBQLN2 condensates than those with wild-type UBQLN2. Most strikingly, exogenously expressed P506T UBQLN2 forms the lowest number of stress-induced condensates of all UBQLN2 mutants, and these condensates are significantly smaller than those of wild-type UBQLN2. Fluorescence recovery after photobleaching (FRAP) analysis of UBQLN2 condensates revealed higher immobile fractions for UBQLN2 mutants, especially P506T. P497S and P497H mutations differentially impact condensate properties, demonstrating that the effects of ALS-linked mutations are both position- and amino acid-dependent. Collectively, our data show that disease mutations hinder assembly and alter viscoelastic properties of stress-induced UBQLN2 condensates, potentially leading to aggregates commonly observed in ALS.
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Affiliation(s)
- Julia F Riley
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
| | | | - Amber K Rusnock
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Carlos A Castañeda
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
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15
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Yamaguchi M, Lee IS, Jantrapirom S, Suda K, Yoshida H. Drosophila models to study causative genes for human rare intractable neurological diseases. Exp Cell Res 2021; 403:112584. [PMID: 33812867 DOI: 10.1016/j.yexcr.2021.112584] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 12/11/2022]
Abstract
Drosophila is emerging as a convenient model for investigating human diseases. Functional homologues of almost 75% of human disease-related genes are found in Drosophila. Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease that causes defects in motoneurons. Charcot-Marie-Tooth disease (CMT) is one of the most commonly found inherited neuropathies affecting both motor and sensory neurons. No effective therapy has been established for either of these diseases. In this review, after overviewing ALS, Drosophila models targeting several ALS-causing genes, including TDP-43, FUS and Ubiquilin2, are described with their genetic interactants. Then, after overviewing CMT, examples of Drosophila models targeting several CMT-causing genes, including mitochondria-related genes and FIG 4, are also described with their genetic interactants. In addition, we introduce Sotos syndrome caused by mutations in the epigenetic regulator gene NSD1. Lastly, several genes and pathways that commonly interact with ALS- and/or CMT-causing genes are described. In the case of ALS and CMT that have many causative genes, it may be not practical to perform gene therapy for each of the many disease-causing genes. The possible uses of the common genes and pathways as novel diagnosis markers and effective therapeutic targets are discussed.
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Affiliation(s)
- Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan; Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Seika-cho, Kyoto, 619-0237, Japan
| | - Im-Soon Lee
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Salinee Jantrapirom
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kojiro Suda
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
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16
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Wang S, Tatman M, Monteiro MJ. Overexpression of UBQLN1 reduces neuropathology in the P497S UBQLN2 mouse model of ALS/FTD. Acta Neuropathol Commun 2020; 8:164. [PMID: 33028421 PMCID: PMC7539388 DOI: 10.1186/s40478-020-01039-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/22/2020] [Indexed: 12/14/2022] Open
Abstract
Missense mutations in UBQLN2 cause X-linked dominant inheritance of amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD). UBQLN2 belongs to a family of four highly homologous proteins expressed in humans that play diverse roles in maintaining proteostasis, but whether one isoform can substitute for another is not known. Here, we tested whether overexpression of UBQLN1 can alleviate disease in the P497S UBQLN2 mouse model of ALS/FTD by crossing transgenic (Tg) mouse lines expressing the two proteins and characterizing the resulting genotypes using a battery of pathologic and behavioral tests. The pathologic findings revealed UBQLN1 overexpression dramatically reduced the burden of UBQLN2 inclusions, neuronal loss and disturbances in proteostasis in double Tg mice compared to single P497S Tg mice. The beneficial effects of UBQLN1 overexpression were primarily confirmed by behavioral improvements seen in rotarod performance and grip strength in male, but not female mice. Paradoxically, although UBQLN1 overexpression reduced pathologic signatures of disease in P497S Tg mice, female mice had larger percentage of body weight loss than males, and this correlated with a corresponding lack of behavioral improvements in the females. These findings lead us to speculate that methods to upregulate UBQLN1 expression may reduce pathogenicity caused by UBQLN2 mutations, but may also lead to gender-specific outcomes that will have to be carefully weighed with the therapeutic benefits of UBQLN1 upregulation.
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17
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Halloran M, Ragagnin AMG, Vidal M, Parakh S, Yang S, Heng B, Grima N, Shahheydari H, Soo KY, Blair I, Guillemin GJ, Sundaramoorthy V, Atkin JD. Amyotrophic lateral sclerosis-linked UBQLN2 mutants inhibit endoplasmic reticulum to Golgi transport, leading to Golgi fragmentation and ER stress. Cell Mol Life Sci 2020; 77:3859-3873. [PMID: 31802140 PMCID: PMC11105036 DOI: 10.1007/s00018-019-03394-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/28/2019] [Accepted: 11/22/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative diseases that are related genetically and pathologically. Mutations in the UBQLN2 gene, encoding the ubiquitin-like protein ubiquilin2, are associated with familial ALS/FTD, but the pathophysiological mechanisms remain unclear. Here, we demonstrate that ALS/FTD UBQLN2 mutants P497H and P506T inhibit protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus in neuronal cells. In addition, we observed that Sec31-positive ER exit sites are clustered in UBQLN2T487I patient spinal cord tissues. Both the ER-Golgi intermediate (ERGIC) compartment and the Golgi become disorganised and fragmented. This activates ER stress and inhibits ER-associated degradation. Hence, this study highlights perturbations in secretory protein trafficking and ER homeostasis as pathogenic mechanisms associated with ALS/FTD-associated forms of UBQLN2.
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Affiliation(s)
- Mark Halloran
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Audrey M G Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Sonam Parakh
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Shu Yang
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Benjamin Heng
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Natalie Grima
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Kai-Ying Soo
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Ian Blair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Gilles J Guillemin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Vinod Sundaramoorthy
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia.
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, Australia.
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18
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Zheng T, Yang Y, Castañeda CA. Structure, dynamics and functions of UBQLNs: at the crossroads of protein quality control machinery. Biochem J 2020; 477:3471-3497. [PMID: 32965492 PMCID: PMC7737201 DOI: 10.1042/bcj20190497] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Cells rely on protein homeostasis to maintain proper biological functions. Dysregulation of protein homeostasis contributes to the pathogenesis of many neurodegenerative diseases and cancers. Ubiquilins (UBQLNs) are versatile proteins that engage with many components of protein quality control (PQC) machinery in cells. Disease-linked mutations of UBQLNs are most commonly associated with amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neurodegenerative disorders. UBQLNs play well-established roles in PQC processes, including facilitating degradation of substrates through the ubiquitin-proteasome system (UPS), autophagy, and endoplasmic-reticulum-associated protein degradation (ERAD) pathways. In addition, UBQLNs engage with chaperones to sequester, degrade, or assist repair of misfolded client proteins. Furthermore, UBQLNs regulate DNA damage repair mechanisms, interact with RNA-binding proteins (RBPs), and engage with cytoskeletal elements to regulate cell differentiation and development. Important to the myriad functions of UBQLNs are its multidomain architecture and ability to self-associate. UBQLNs are linked to numerous types of cellular puncta, including stress-induced biomolecular condensates, autophagosomes, aggresomes, and aggregates. In this review, we focus on deciphering how UBQLNs function on a molecular level. We examine the properties of oligomerization-driven interactions among the structured and intrinsically disordered segments of UBQLNs. These interactions, together with the knowledge from studies of disease-linked mutations, provide significant insights to UBQLN structure, dynamics and function.
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Affiliation(s)
- Tongyin Zheng
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Yiran Yang
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Carlos A. Castañeda
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Departments of Biology and Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Bioinspired Institute, and the Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY 13244, U.S.A
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19
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Umair M, Ballow M, Asiri A, Alyafee Y, Al Tuwaijri A, Alhamoudi KM, Aloraini T, Abdelhakim M, Althagafi AT, Kafkas S, Alsubaie L, Alrifai MT, Hoehndorf R, Alfares A, Alfadhel M. EMC10 homozygous variant identified in a family with global developmental delay, mild intellectual disability, and speech delay. Clin Genet 2020; 98:555-561. [PMID: 32869858 PMCID: PMC7756316 DOI: 10.1111/cge.13842] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/27/2022]
Abstract
In recent years, several genes have been implicated in the variable disease presentation of global developmental delay (GDD) and intellectual disability (ID). The endoplasmic reticulum membrane protein complex (EMC) family is known to be involved in GDD and ID. Homozygous variants of EMC1 are associated with GDD, scoliosis, and cerebellar atrophy, indicating the relevance of this pathway for neurogenetic disorders. EMC10 is a bone marrow‐derived angiogenic growth factor that plays an important role in infarct vascularization and promoting tissue repair. However, this gene has not been previously associated with human disease. Herein, we describe a Saudi family with two individuals segregating a recessive neurodevelopmental disorder. Both of the affected individuals showed mild ID, speech delay, and GDD. Whole‐exome sequencing (WES) and Sanger sequencing were performed to identify candidate genes. Further, to elucidate the functional effects of the variant, quantitative real‐time PCR (RT‐qPCR)‐based expression analysis was performed. WES revealed a homozygous splice acceptor site variant (c.679‐1G>A) in EMC10 (chromosome 19q13.33) that segregated perfectly within the family. RT‐qPCR showed a substantial decrease in the relative EMC10 gene expression in the patients, indicating the pathogenicity of the identified variant. For the first time in the literature, the EMC10 gene variant was associated with mild ID, speech delay, and GDD. Thus, this gene plays a key role in developmental milestones, with the potential to cause neurodevelopmental disorders in humans.
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Affiliation(s)
- Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Mariam Ballow
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Abdulaziz Asiri
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Yusra Alyafee
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Abeer Al Tuwaijri
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Kheloud M Alhamoudi
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Taghrid Aloraini
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Marwa Abdelhakim
- Computer, Electrical and Mathematical Sciences & Engineering Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Azza Thamer Althagafi
- Computer, Electrical and Mathematical Sciences & Engineering Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,College of Computers and Information Technology, Taif University, Taif, Saudi Arabia
| | - Senay Kafkas
- Computer, Electrical and Mathematical Sciences & Engineering Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Lamia Alsubaie
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Muhammad Talal Alrifai
- Department of Pediatrics, Division of Neurology, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Robert Hoehndorf
- Computer, Electrical and Mathematical Sciences & Engineering Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Ahmed Alfares
- Department of Pediatrics, College of Medicine, Qassim University, Saudi Arabia
| | - Majid Alfadhel
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia.,Division of Genetics, Department of Pediatrics, King Abdullah Specialized Children's Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia
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20
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Wu JJ, Cai A, Greenslade JE, Higgins NR, Fan C, Le NTT, Tatman M, Whiteley AM, Prado MA, Dieriks BV, Curtis MA, Shaw CE, Siddique T, Faull RLM, Scotter EL, Finley D, Monteiro MJ. ALS/FTD mutations in UBQLN2 impede autophagy by reducing autophagosome acidification through loss of function. Proc Natl Acad Sci U S A 2020; 117:15230-15241. [PMID: 32513711 PMCID: PMC7334651 DOI: 10.1073/pnas.1917371117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in UBQLN2 cause amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neurodegenerations. However, the mechanism by which the UBQLN2 mutations cause disease remains unclear. Alterations in proteins involved in autophagy are prominent in neuronal tissue of human ALS UBQLN2 patients and in a transgenic P497S UBQLN2 mouse model of ALS/FTD, suggesting a pathogenic link. Here, we show UBQLN2 functions in autophagy and that ALS/FTD mutant proteins compromise this function. Inactivation of UBQLN2 expression in HeLa cells reduced autophagic flux and autophagosome acidification. The defect in acidification was rescued by reexpression of wild type (WT) UBQLN2 but not by any of the five different UBQLN2 ALS/FTD mutants tested. Proteomic analysis and immunoblot studies revealed P497S mutant mice and UBQLN2 knockout HeLa and NSC34 cells have reduced expression of ATP6v1g1, a critical subunit of the vacuolar ATPase (V-ATPase) pump. Knockout of UBQLN2 expression in HeLa cells decreased turnover of ATP6v1g1, while overexpression of WT UBQLN2 increased biogenesis of ATP6v1g1 compared with P497S mutant UBQLN2 protein. In vitro interaction studies showed that ATP6v1g1 binds more strongly to WT UBQLN2 than to ALS/FTD mutant UBQLN2 proteins. Intriguingly, overexpression of ATP6v1g1 in UBQLN2 knockout HeLa cells increased autophagosome acidification, suggesting a therapeutic approach to overcome the acidification defect. Taken together, our findings suggest that UBQLN2 mutations drive pathogenesis through a dominant-negative loss-of-function mechanism in autophagy and that UBQLN2 functions as an important regulator of the expression and stability of ATP6v1g1. These findings may have important implications for devising therapies to treat UBQLN2-linked ALS/FTD.
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Affiliation(s)
- Josephine J Wu
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Ashley Cai
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Jessie E Greenslade
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Nicole R Higgins
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Cong Fan
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Nhat T T Le
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Micaela Tatman
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | | | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Birger V Dieriks
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute, King's College London, WC2R 2LS London, United Kingdom
- Maurice Wohl Clinical Neuroscience Institute, King's College London, SE5 9RT London, United Kingdom
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, WC2R 2LS London, United Kingdom
| | - Teepu Siddique
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging, University of Auckland, 1010 Auckland, New Zealand
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
| | - Emma L Scotter
- Centre for Brain Research, University of Auckland, 1010 Auckland, New Zealand
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, 1010 Auckland, New Zealand
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201;
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21
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UBQLN2 Promotes the Production of Type I Interferon via the TBK1-IRF3 Pathway. Cells 2020; 9:cells9051205. [PMID: 32413959 PMCID: PMC7290724 DOI: 10.3390/cells9051205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations of Ubiquilin 2 (UBQLN2) or TANK-binding kinase 1 (TBK1) are associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). However, the mechanisms whereby UBQLN2 or TBK1 mutations lead to ALS and FTD remain unclear. Here, we explored the effect of UBQLN2 on TBK1 in HEK-293T cells or in CRISPR-Cas9-mediated IRF3 and IRF7 knockout (KO) cells. We found an interaction between TBK1 and UBQLN2, which was affected by ALS/FTD-linked mutations in TBK1 or UBQLN2. Co-expression of UBQLN2 with TBK1 elevated the protein level of TBK1 as well as the phosphorylation of TBK1 and IRF3 in a UBQLN2 dose-dependent manner, and this phosphorylation was reduced by mutant UBQLN2. In addition, the cellular production of IFN1 and related pro-inflammatory cytokines was substantially elevated when UBQLN2 and TBK1 were co-expressed, which was also decreased by mutant UBQLN2. Functional assay revealed that mutant UBQLN2 significantly reduced the binding affinity of TBK1 for its partners, including IRF3, (SQSTM1)/p62 and optineurin (OPTN). Moreover, complete loss of IRF3 abolished the induction of IFN1 and related pro-inflammatory cytokines enhanced by UBQLN2 in HEK-293T cells, whereas no significant change in IRF7 knockout cells was observed. Thus, our findings suggest that UBQLN2 promotes IRF3 phosphorylation via TBK1, leading to enhanced IFN1 induction, and also imply that the dysregulated TBK1-IRF3 pathway may play a role in UBQLN2-related neurodegeneration.
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22
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Cabet S, Lesca G, Labalme A, Des Portes V, Guibaud L, Sanlaville D, Pons L. Novel truncating and missense variants extending the spectrum of EMC1-related phenotypes, causing autism spectrum disorder, severe global development delay and visual impairment. Eur J Med Genet 2020; 63:103897. [PMID: 32092440 DOI: 10.1016/j.ejmg.2020.103897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/13/2020] [Accepted: 02/19/2020] [Indexed: 11/15/2022]
Abstract
The EMC1 gene, located on 1p36.13, encodes the subunit 1 of the endoplasmic reticulum-membrane protein complex, a highly conserved and ubiquitous multiprotein transmembrane complex. Pathogenic monoallelic and biallelic variants in EMC1 in humans have been reported only in six families, causing isolated visual impairment or in association with psychomotor retardation and cerebellar atrophy. We report a ten-year-old boy, born to unrelated parents, with early-onset severe global development delay due to novel EMC1 biallelic pathogenic variants. A truncating variant, p.(Tyr378*) and a missense variant, p.(Phe953Ser), located in exon 11 and 23 of EMC1 gene respectively, have been found by reanalysis of exome sequencing data. The proband's phenotype included several signs that overlap with the phenotype of previously reported patients, associating severe global developmental delay, abnormal ophthalmological examination, and postnatal slow-down of the head circumference growth. Some distinguishing clinical signs were observed in comparison to patients from literature, such as autism spectrum disorder, absence of seizures, scoliosis or facial dysmorphic features, thus extending the spectrum of EMC1-related phenotypes. Similarly, brain MRI, performed at 2 years, showed normal cerebellar volume and structure, whereas cerebellar atrophy was described in literature. Moreover, difficulties of clinical differential diagnosis between EMC1-associated disease and other etiologies of global development delay support the importance of large-scale genetic investigations. Our diagnostic approach, through reanalysis of exome sequencing data, highlights the importance of reconsidering initial negative results for patients with a strong suspicion of genetic disease, and to update analytic pipelines in order to improve the diagnostic yield of exome sequencing.
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Affiliation(s)
- Sara Cabet
- Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Department of Radiology, Hospices Civils de Lyon, Groupement Hospitalier Est, France
| | - Gaetan Lesca
- Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Claude Bernard Lyon 1 University, France; Claude Bernard Lyon 1 University, France
| | - Audrey Labalme
- Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France
| | - Vincent Des Portes
- Department of Pediatric Neurology, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Claude Bernard Lyon 1 University, France
| | - Laurent Guibaud
- Department of Radiology, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Claude Bernard Lyon 1 University, France
| | - Damien Sanlaville
- Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Claude Bernard Lyon 1 University, France; Claude Bernard Lyon 1 University, France
| | - Linda Pons
- Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Claude Bernard Lyon 1 University, France.
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Vicencio E, Beltrán S, Labrador L, Manque P, Nassif M, Woehlbier U. Implications of Selective Autophagy Dysfunction for ALS Pathology. Cells 2020; 9:cells9020381. [PMID: 32046060 PMCID: PMC7072226 DOI: 10.3390/cells9020381] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disorder that progressively affects motor neurons in the brain and spinal cord. Due to the biological complexity of the disease, its etiology remains unknown. Several cellular mechanisms involved in the neurodegenerative process in ALS have been found, including the loss of RNA and protein homeostasis, as well as mitochondrial dysfunction. Insoluble protein aggregates, damaged mitochondria, and stress granules, which contain RNA and protein components, are recognized and degraded by the autophagy machinery in a process known as selective autophagy. Autophagy is a highly dynamic process whose dysregulation has now been associated with neurodegenerative diseases, including ALS, by numerous studies. In ALS, the autophagy process has been found deregulated in both familial and sporadic cases of the disease. Likewise, mutations in genes coding for proteins involved in the autophagy machinery have been reported in ALS patients, including selective autophagy receptors. In this review, we focus on the role of selective autophagy in ALS pathology.
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Affiliation(s)
- Emiliano Vicencio
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Sebastián Beltrán
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Luis Labrador
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Patricio Manque
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
| | - Melissa Nassif
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
| | - Ute Woehlbier
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
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Affinity Purification of NF1 Protein-Protein Interactors Identifies Keratins and Neurofibromin Itself as Binding Partners. Genes (Basel) 2019; 10:genes10090650. [PMID: 31466283 PMCID: PMC6770187 DOI: 10.3390/genes10090650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/09/2019] [Accepted: 08/19/2019] [Indexed: 12/23/2022] Open
Abstract
Neurofibromatosis Type 1 (NF1) is caused by pathogenic variants in the NF1 gene encoding neurofibromin. Definition of NF1 protein–protein interactions (PPIs) has been difficult and lacks replication, making it challenging to define binding partners that modulate its function. We created a novel tandem affinity purification (TAP) tag cloned in frame to the 3’ end of the full-length murine Nf1 cDNA (mNf1). We show that this cDNA is functional and expresses neurofibromin, His-Tag, and can correct p-ERK/ERK ratios in NF1 null HEK293 cells. We used this affinity tag to purify binding partners with Strep-Tactin®XT beads and subsequently, identified them via mass spectrometry (MS). We found the tagged mNf1 can affinity purify human neurofibromin and vice versa, indicating that neurofibromin oligomerizes. We identify 21 additional proteins with high confidence of interaction with neurofibromin. After Metacore network analysis of these 21 proteins, eight appear within the same network, primarily keratins regulated by estrogen receptors. Previously, we have shown that neurofibromin levels negatively regulate keratin expression. Here, we show through pharmacological inhibition that this is independent of Ras signaling, as the inhibitors, selumetinib and rapamycin, do not alter keratin expression. Further characterization of neurofibromin oligomerization and binding partners could aid in discovering new neurofibromin functions outside of Ras regulation, leading to novel drug targets.
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25
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Renaud L, Picher-Martel V, Codron P, Julien JP. Key role of UBQLN2 in pathogenesis of amyotrophic lateral sclerosis and frontotemporal dementia. Acta Neuropathol Commun 2019; 7:103. [PMID: 31319884 PMCID: PMC6889556 DOI: 10.1186/s40478-019-0758-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 06/22/2019] [Indexed: 12/11/2022] Open
Abstract
Ubiquilin-2 (UBQLN2) is a member of the ubiquilin family, actively implicated in the degradation of misfolded and redundant proteins through the ubiquitin-proteasome system and macroautophagy. UBQLN2 received much attention after the discovery of gene mutations in amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). The abnormal presence of positive UBQLN2 inclusion in the cytosol of degenerating motor neurons of familial and sporadic forms of ALS patients has been newly related to neurodegeneration. Only recently, data have emerged on its role in liquid-liquid phase separation, in stress granule development and in the formation of secondary amyloid structures. Furthermore, several animal models are available to investigate its involvement in TDP-43 pathology and neuroinflammation in ALS. This review addresses the molecular pathogenetic pathways involving UBQLN2 abnormalities which are converging toward defects in clearance mechanisms. UBQLN2.
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26
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Harman CA, Monteiro MJ. The specificity of ubiquitin binding to ubiquilin-1 is regulated by sequences besides its UBA domain. Biochim Biophys Acta Gen Subj 2019; 1863:1568-1574. [PMID: 31175912 DOI: 10.1016/j.bbagen.2019.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/24/2019] [Accepted: 06/03/2019] [Indexed: 12/12/2022]
Abstract
UBQLN proteins regulate proteostasis by facilitating clearance of misfolded proteins through the proteasome and autophagy degradation pathways. Consistent with its proteasomal function, UBQLN proteins contain both UBL and UBA domains, which bind subunits of the proteasome, including the S5a subunit, and ubiquitin chains, respectively. Conclusions regarding the binding properties of UBQLN proteins have been derived principally through studies of its individual domains, not the full-length (FL) proteins. Here we describe the in vitro binding properties of FL-UBQLN1 with the S5a subunit of the proteasome and two different lysine-linked (K48 or K63) ubiquitin chains. We show that in contrast to its isolated UBA domain, which binds almost equally well with both K48 and K63 ubiquitin chains, FL UBQLN1 binds preferentially with K63 chains. Furthermore, we show that deletion of the UBL domain from UBQLN1 abrogates ubiquitin binding. Taken together these results suggest that sequences outside of the UBA domain in UBQLN1 function to regulate the specificity and binding with different ubiquitin moieties. We also show that the UBL domain of UBQLN1 is required for S5a binding and that its binding to UBQLN1, in turn, enhances K48 ubiquitin chain binding to the complex. We discuss the implications of our findings with the known function of UBQLN proteins in protein degradation.
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Affiliation(s)
- Christine A Harman
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.
| | - Mervyn J Monteiro
- Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.
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27
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Non-Proteasomal UbL-UbA Family of Proteins in Neurodegeneration. Int J Mol Sci 2019; 20:ijms20081893. [PMID: 30999567 PMCID: PMC6514573 DOI: 10.3390/ijms20081893] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/09/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022] Open
Abstract
Ubiquitin-like/ubiquitin-associated proteins (UbL-UbA) are a well-studied family of non-proteasomal ubiquitin receptors that are evolutionarily conserved across species. Members of this non-homogenous family facilitate and support proteasomal activity by promoting different effects on proteostasis but exhibit diverse extra-proteasomal activities. Dysfunctional UbL-UbA proteins render cells, particularly neurons, more susceptible to stressors or aging and may cause earlier neurodegeneration. In this review, we summarized the properties and functions of UbL-UbA family members identified to date, with an emphasis on new findings obtained using Drosophila models showing a direct or indirect role in some neurodegenerative diseases.
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28
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Kim SH, Stiles SG, Feichtmeier JM, Ramesh N, Zhan L, Scalf MA, Smith LM, Pandey UB, Tibbetts RS. Mutation-dependent aggregation and toxicity in a Drosophila model for UBQLN2-associated ALS. Hum Mol Genet 2019; 27:322-337. [PMID: 29161404 DOI: 10.1093/hmg/ddx403] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/14/2017] [Indexed: 12/12/2022] Open
Abstract
Members of the conserved ubiquilin (UBQLN) family of ubiquitin (Ub) chaperones harbor an antipodal UBL (Ub-like)-UBA (Ub-associated) domain arrangement and participate in proteasome and autophagosome-mediated protein degradation. Mutations in a proline-rich-repeat region (PRR) of UBQLN2 cause amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD); however, neither the normal functions of the PRR nor impacts of ALS-associated mutations within it are well understood. In this study, we show that ALS mutations perturb UBQLN2 solubility and folding in a mutation-specific manner. Biochemical impacts of ALS mutations were additive, transferable to UBQLN1, and resulted in enhanced Ub association. A Drosophila melanogaster model for UBQLN2-associated ALS revealed that both wild-type and ALS-mutant UBQLN2 alleles disrupted Ub homeostasis; however, UBQLN2ALS mutants exhibited age-dependent aggregation and caused toxicity phenotypes beyond those seen for wild-type UBQLN2. Although UBQLN2 toxicity was not correlated with aggregation in the compound eye, aggregation-prone UBQLN2 mutants elicited climbing defects and neuromuscular junctions (NMJ) abnormalities when expressed in neurons. An UBA domain mutation that abolished Ub binding also diminished UBQLN2 toxicity, implicating Ub binding in the underlying pathomechanism. We propose that ALS-associated mutations in UBQLN2 disrupt folding and that both aggregated species and soluble oligomers instigate neuron autonomous toxicity through interference with Ub homeostasis.
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Affiliation(s)
- Sang Hwa Kim
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Shannon G Stiles
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Joseph M Feichtmeier
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Nandini Ramesh
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Lihong Zhan
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Mark A Scalf
- Department of Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Randal S Tibbetts
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
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Ubiquilin 2 modulates ALS/FTD-linked FUS-RNA complex dynamics and stress granule formation. Proc Natl Acad Sci U S A 2018; 115:E11485-E11494. [PMID: 30442662 DOI: 10.1073/pnas.1811997115] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The ubiquitin-like protein ubiquilin 2 (UBQLN2) has been genetically and pathologically linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), but its normal cellular functions are not well understood. In a search for UBQLN2-interacting proteins, we found an enrichment of stress granule (SG) components, including ALS/FTD-linked heterogeneous ribonucleoprotein fused in sarcoma (FUS). Through the use of an optimized SG detection method, we observed UBQLN2 and its interactors at SGs. A low complexity, Sti1-like repeat region in UBQLN2 was sufficient for its localization to SGs. Functionally, UBQLN2 negatively regulated SG formation. UBQLN2 increased the dynamics of FUS-RNA interaction and promoted the fluidity of FUS-RNA complexes at a single-molecule level. This solubilizing effect corresponded to a dispersal of FUS liquid droplets in vitro and a suppression of FUS SG formation in cells. ALS-linked mutations in UBQLN2 reduced its association with FUS and impaired its function in regulating FUS-RNA complex dynamics and SG formation. These results reveal a previously unrecognized role for UBQLN2 in regulating the early stages of liquid-liquid phase separation by directly modulating the fluidity of protein-RNA complexes and the dynamics of SG formation.
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30
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Abstract
Under stress, certain eukaryotic proteins and RNA assemble to form membraneless organelles known as stress granules. The most well-studied stress granule components are RNA-binding proteins that undergo liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by intrinsically disordered low-complexity domains (LCDs). Here we show that stress granules include proteasomal shuttle factor UBQLN2, an LCD-containing protein structurally and functionally distinct from RNA-binding proteins. In vitro, UBQLN2 exhibits LLPS at physiological conditions. Deletion studies correlate oligomerization with UBQLN2's ability to phase-separate and form stress-induced cytoplasmic puncta in cells. Using nuclear magnetic resonance (NMR) spectroscopy, we mapped weak, multivalent interactions that promote UBQLN2 oligomerization and LLPS. Ubiquitin or polyubiquitin binding, obligatory for UBQLN2's biological functions, eliminates UBQLN2 LLPS, thus serving as a switch between droplet and disperse phases. We postulate that UBQLN2 LLPS enables its recruitment to stress granules, where its interactions with ubiquitinated substrates reverse LLPS to enable shuttling of clients out of stress granules.
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31
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Maurel C, Dangoumau A, Marouillat S, Brulard C, Chami A, Hergesheimer R, Corcia P, Blasco H, Andres CR, Vourc'h P. Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration. Mol Neurobiol 2018; 55:6480-6499. [PMID: 29322304 DOI: 10.1007/s12035-017-0856-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.
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Affiliation(s)
- C Maurel
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Dangoumau
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - S Marouillat
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - C Brulard
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Chami
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - R Hergesheimer
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - P Corcia
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Neurologie, CHRU de Tours, 37044, Tours, France
| | - H Blasco
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - C R Andres
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - P Vourc'h
- UMR INSERM U1253, Université de Tours, 37032, Tours, France.
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France.
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Galdiero F, Bello AM, Spina A, Capiluongo A, Liuu S, De Marco M, Rosati A, Capunzo M, Napolitano M, Vuttariello E, Monaco M, Califano D, Turco MC, Chiappetta G, Vinh J, Chiappetta G. Identification of BAG3 target proteins in anaplastic thyroid cancer cells by proteomic analysis. Oncotarget 2018; 9:8016-8026. [PMID: 29487711 PMCID: PMC5814278 DOI: 10.18632/oncotarget.23858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 10/30/2017] [Indexed: 11/25/2022] Open
Abstract
BAG3 protein is an apoptosis inhibitor and is highly expressed in Anaplastic Thyroid Cancer. We investigated the entire set of proteins modulated by BAG3 silencing in the human anaplastic thyroid 8505C cancer cells by using the Stable-Isotope Labeling by Amino acids in Cell culture strategy combined with mass spectrometry analysis. By this approach we identified 37 up-regulated and 54 down-regulated proteins in BAG3-silenced cells. Many of these proteins are reportedly involved in tumor progression, invasiveness and resistance to therapies. We focused our attention on an oncogenic protein, CAV1, and a tumor suppressor protein, SERPINB2, that had not previously been reported to be modulated by BAG3. Their expression levels in BAG3-silenced cells were confirmed by qRT-PCR and western blot analyses, disclosing two novel targets of BAG3 pro-tumor activity. We also examined the dataset of proteins obtained by the quantitative proteomics analysis using two tools, Downstream Effect Analysis and Upstream Regulator Analysis of the Ingenuity Pathways Analysis software. Our analyses confirm the association of the proteome profile observed in BAG3-silenced cells with an increase in cell survival and a decrease in cell proliferation and invasion, and highlight the possible involvement of four tumor suppressor miRNAs and TP53/63 proteins in BAG3 activity.
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Affiliation(s)
- Francesca Galdiero
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Anna Maria Bello
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Anna Spina
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Anna Capiluongo
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Sophie Liuu
- ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris, France
| | | | - Alessandra Rosati
- Biouniversa s.r.l., University of Salerno, Fisciano, Italy.,Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi (SA), Italy
| | - Mario Capunzo
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi (SA), Italy
| | - Maria Napolitano
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Emilia Vuttariello
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Mario Monaco
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Daniela Califano
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Maria Caterina Turco
- Biouniversa s.r.l., University of Salerno, Fisciano, Italy.,Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi (SA), Italy.,"SS. Giovanni di Dio e Ruggi d'Aragona-Schola Medica Salernitana", University of Salerno Hospital, Salerno, Italy
| | - Gennaro Chiappetta
- Functional Genomic Unit, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italia
| | - Joëlle Vinh
- ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris, France
| | - Giovanni Chiappetta
- ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris, France
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Dedigama-Arachchige PM, Acharige NPN, Pflum MKH. Identification of PP1-Gadd34 substrates involved in the unfolded protein response using K-BIPS, a method for phosphatase substrate identification. Mol Omics 2018; 14:121-133. [PMID: 29623310 DOI: 10.1039/c7mo00064b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphorylation is a key post-translational modification in cell signaling, which is regulated by the equilibrium activities of kinases and phosphatases. The biological significance of many phosphorylation events remains poorly characterized due to the scarcity of tools to discover phosphatases substrates. In prior work, we established kinase-catalyzed biotinylation where kinases accept the γ-modified ATP analog, ATP-biotin, to label phosphoproteins. Here, we developed a novel method to study substrates of phosphatases using kinase-catalyzed biotinylation termed K-BIPS (Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates). In a proof-of-concept experiment, K-BIPS was initially used to explore the substrates of phosphatases inhibited by okadaic acid. Many known phosphatase substrates were observed, confirming K-BIPS as a valid phosphatase substrate identification tool. Then, as a further application, K-BIPS was used to discover the substrates of the PP1-Gadd34 phosphatase complex in the context of unfolded protein response (UPR). In addition to the known substrate eIF2α, K-BIPS revealed several novel substrates, suggesting a more prominent role for the PP1-Gadd34 complex in UPR than previously appreciated. Overall, the two studies establish K-BIPS as a powerful tool to discover the cellular substrates of phosphatases.
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Tang SS, Li J, Tan L, Yu JT. Genetics of Frontotemporal Lobar Degeneration: From the Bench to the Clinic. J Alzheimers Dis 2017; 52:1157-76. [PMID: 27104909 DOI: 10.3233/jad-160236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a clinically heterogeneous neurodegenerative disease with a strong genetic component. In this review, we summarize most common mutations in MAPT, GRN, and C90RF72, as well as less common mutations in VCP, CHMP2B, TARDBP, FUS gene and so on. Several guidelines have been developed to help gene testing based on genotype-phenotype correlation, the underlying histopathological subtypes, and the neuroanatomic associations. Furthermore, we also summarize molecular pathways implicated by genes and novel targets for FTLD prevention and management in recent years.
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35
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Nyalwidhe JO, Gallagher GR, Glenn LM, Morris MA, Vangala P, Jurczyk A, Bortell R, Harlan DM, Wang JP, Nadler JL. Coxsackievirus-Induced Proteomic Alterations in Primary Human Islets Provide Insights for the Etiology of Diabetes. J Endocr Soc 2017; 1:1272-1286. [PMID: 29264452 PMCID: PMC5686651 DOI: 10.1210/js.2017-00278] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/06/2017] [Indexed: 12/15/2022] Open
Abstract
Enteroviral infections have been associated with the development of type 1 diabetes (T1D), a chronic inflammatory disease characterized by autoimmune destruction of insulin-producing pancreatic beta cells. Cultured human islets, including the insulin-producing beta cells, can be infected with coxsackievirus B4 (CVB4) and thus are useful for understanding cellular responses to infection. We performed quantitative mass spectrometry analysis on cultured primary human islets infected with CVB4 to identify molecules and pathways altered upon infection. Corresponding uninfected controls were included in the study for comparative protein expression analyses. Proteins were significantly and differentially regulated in human islets challenged with virus compared with their uninfected counterparts. Complementary analyses of gene transcripts in CVB4-infected primary islets over a time course validated the induction of RNA transcripts for many of the proteins that were increased in the proteomics studies. Notably, infection with CVB4 results in a considerable decrease in insulin. Genes/proteins modulated during CVB4 infection also include those involved in activation of immune responses, including type I interferon pathways linked to T1D pathogenesis and with antiviral, cell repair, and inflammatory properties. Our study applies proteomics analyses to cultured human islets challenged with virus and identifies target proteins that could be useful in T1D interventions.
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Affiliation(s)
- Julius O Nyalwidhe
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia 23501.,Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Glen R Gallagher
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Lindsey M Glenn
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Margaret A Morris
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Pranitha Vangala
- Department of Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Agata Jurczyk
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Rita Bortell
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - David M Harlan
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jennifer P Wang
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jerry L Nadler
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
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36
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Teyssou E, Chartier L, Amador MDM, Lam R, Lautrette G, Nicol M, Machat S, Da Barroca S, Moigneu C, Mairey M, Larmonier T, Saker S, Dussert C, Forlani S, Fontaine B, Seilhean D, Bohl D, Boillée S, Meininger V, Couratier P, Salachas F, Stevanin G, Millecamps S. Novel UBQLN2 mutations linked to amyotrophic lateral sclerosis and atypical hereditary spastic paraplegia phenotype through defective HSP70-mediated proteolysis. Neurobiol Aging 2017; 58:239.e11-239.e20. [PMID: 28716533 DOI: 10.1016/j.neurobiolaging.2017.06.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/14/2017] [Accepted: 06/20/2017] [Indexed: 11/26/2022]
Abstract
Mutations in UBQLN2 have been associated with rare cases of X-linked juvenile and adult forms of amyotrophic lateral sclerosis (ALS) and ALS linked to frontotemporal dementia (FTD). Here, we report 1 known (c.1489C>T, p.Pro497Ser, P497S) and 3 novel (c.1481C>T, p.Pro494Leu, P494L; c.1498C>T, p.Pro500Ser, P500S; and c.1516C>G, p.Pro506Ala, P506A) missense mutations in the PXX domain of UBQLN2 in familial motor neuron diseases including ALS and spastic paraplegia (SP). A novel missense mutation (c.1462G>A, p.Ala488Thr, A488T) adjacent to this hotspot UBQLN2 domain was identified in a sporadic case of ALS. These mutations are conserved in mammals, are absent from ExAC and gnomAD browsers, and are predicted to be deleterious by SIFT in silico analysis. Patient lymphoblasts carrying a UBQLN2 mutation showed absence of ubiquilin-2 accumulation, disrupted binding with HSP70, and impaired autophagic pathway. Our results confirm the role of PXX repeat in ALS pathogenesis, show that UBQLN2-linked disease can manifest like a SP phenotype, evidence a highly reduced disease penetrance in females carrying UBQLN2 mutations, which is important information for genetic counseling, and underline the pivotal role of ubiquilin-2 in proteolysis regulation pathways.
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Affiliation(s)
- Elisa Teyssou
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Laura Chartier
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Maria-Del-Mar Amador
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Roselina Lam
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Géraldine Lautrette
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Marie Nicol
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Selma Machat
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - Sandra Da Barroca
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Carine Moigneu
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Mathilde Mairey
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Ecole Pratique des Hautes Etudes, EPHE, Université de recherche Paris Sciences et Lettres, Paris, France
| | | | - Safaa Saker
- Banque d'ADN et de cellules du Généthon, Evry, France
| | - Christelle Dussert
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Sylvie Forlani
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Bertrand Fontaine
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Danielle Seilhean
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neuropathologie, APHP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Delphine Bohl
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Séverine Boillée
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Vincent Meininger
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France; Hôpital des Peupliers, Ramsay Générale de Santé, Paris, France
| | - Philippe Couratier
- Service de Neurologie, Centre de ressources et de compétences SLA, CHU Dupuytren, Limoges, France
| | - François Salachas
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de ressources et de compétences SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Giovanni Stevanin
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Ecole Pratique des Hautes Etudes, EPHE, Université de recherche Paris Sciences et Lettres, Paris, France; Centre de Référence de Neurogénétique, Fédération de Génétique, APHP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Stéphanie Millecamps
- Inserm U1127, CNRS UMR7225, Sorbonne Universités, UPMC Univ Paris 6 UMRS1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France.
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Stegmüller J, Synofzik M. New transgenic ALS/FTD models on the rat-walk: An Editorial Highlight for 'Increased Ubqln2 expression causes neuron death in transgenic rats'. J Neurochem 2017; 139:159-161. [PMID: 27723099 DOI: 10.1111/jnc.13775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/10/2016] [Accepted: 08/10/2016] [Indexed: 12/14/2022]
Abstract
This Editorial highlights a study by Huang and colleagues in the current issue of Journal of Neurochemistry. The authors introduce a novel ALS-FTD (amyotrophic lateral sclerosis-frontotemporal dementia) rat model to explore the role of the UBLQN2 gene that has previously been associated with familial ALS-FTD. Over-expression of ubiquilin 2 in the cortex (CTX) and hippocampus of the rat results in ubiquilin 2 aggregates and neurodegeneration together with cognitive deficits. The new rat model not only gives insight into potential molecular underpinnings of ALS-FTD, but also represents an important new tool for future research and therapeutic approaches. Read the highlighted article 'Increased Ubqln2 expression causes neuron death in transgenic rats' on page 285.
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Affiliation(s)
- Judith Stegmüller
- Department of Neurology, University Clinics, RWTH Aachen, Aachen, Germany.
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Research Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
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Shahheydari H, Ragagnin A, Walker AK, Toth RP, Vidal M, Jagaraj CJ, Perri ER, Konopka A, Sultana JM, Atkin JD. Protein Quality Control and the Amyotrophic Lateral Sclerosis/Frontotemporal Dementia Continuum. Front Mol Neurosci 2017; 10:119. [PMID: 28539871 PMCID: PMC5423993 DOI: 10.3389/fnmol.2017.00119] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, has an important regulatory role in cellular function. Protein quality control mechanisms, including protein folding and protein degradation processes, have a crucial function in post-mitotic neurons. Cellular protein quality control relies on multiple strategies, including molecular chaperones, autophagy, the ubiquitin proteasome system, endoplasmic reticulum (ER)-associated degradation (ERAD) and the formation of stress granules (SGs), to regulate proteostasis. Neurodegenerative diseases are characterized by the presence of misfolded protein aggregates, implying that protein quality control mechanisms are dysfunctional in these conditions. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that are now recognized to overlap clinically and pathologically, forming a continuous disease spectrum. In this review article, we detail the evidence for dysregulation of protein quality control mechanisms across the whole ALS-FTD continuum, by discussing the major proteins implicated in ALS and/or FTD. We also discuss possible ways in which protein quality mechanisms could be targeted therapeutically in these disorders and highlight promising protein quality control-based therapeutics for clinical trials.
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Affiliation(s)
- Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Audrey Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Adam K Walker
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Reka P Toth
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Cyril J Jagaraj
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Emma R Perri
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Anna Konopka
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Jessica M Sultana
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe UniversityMelbourne, VIC, Australia
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39
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Amyotrophic Lateral Sclerosis Pathogenesis Converges on Defects in Protein Homeostasis Associated with TDP-43 Mislocalization and Proteasome-Mediated Degradation Overload. Curr Top Dev Biol 2017; 121:111-171. [DOI: 10.1016/bs.ctdb.2016.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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40
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Götzl JK, Lang CM, Haass C, Capell A. Impaired protein degradation in FTLD and related disorders. Ageing Res Rev 2016; 32:122-139. [PMID: 27166223 DOI: 10.1016/j.arr.2016.04.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 03/21/2016] [Accepted: 04/23/2016] [Indexed: 12/12/2022]
Abstract
Impaired protein degradation has been discussed as a cause or consequence of various neurodegenerative diseases, such as Alzheimer's, Parkinson's and Huntington's disease. More recently, evidence accumulated that dysfunctional protein degradation may play a role in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Since in almost all neurodegenerative diseases, protein aggregates are disease-defining hallmarks, it is most likely that impaired protein degradation contributes to disease onset and progression. In the majority of FTD cases, the pathological protein aggregates contain either microtubuleassociated protein tau or TAR DNA-binding protein (TDP)-43. Aggregates are also positive for ubiquitin and p62/sequestosome 1 (SQSTM1) indicating that these aggregates are targeted for degradation. FTD-linked mutations in genes encoding three autophagy adaptor proteins, p62/SQSTM1, ubiquilin 2 and optineurin, indicate that impaired autophagy might cause FTD. Furthermore, the strongest evidence for lysosomal impairment in FTD is provided by the progranulin (GRN) gene, which is linked to FTD and neuronal ceroid lipofuscinosis. In this review, we summarize the observations that have been made during the last years linking the accumulation of disease-associated proteins in FTD to impaired protein degradation pathways. In addition, we take resent findings for nucleocytoplasmic transport defects of TDP-43, as discussed for hexanucleotide repeat expansions in C9orf72 into account and provide a hypothesis how the interplay of altered nuclear transport and protein degradation leads to the accumulation of protein deposits.
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41
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Motor neuron disease, TDP-43 pathology, and memory deficits in mice expressing ALS-FTD-linked UBQLN2 mutations. Proc Natl Acad Sci U S A 2016; 113:E7580-E7589. [PMID: 27834214 DOI: 10.1073/pnas.1608432113] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Missense mutations in ubiquilin 2 (UBQLN2) cause ALS with frontotemporal dementia (ALS-FTD). Animal models of ALS are useful for understanding the mechanisms of pathogenesis and for preclinical investigations. However, previous rodent models carrying UBQLN2 mutations failed to manifest any sign of motor neuron disease. Here, we show that lines of mice expressing either the ALS-FTD-linked P497S or P506T UBQLN2 mutations have cognitive deficits, shortened lifespans, and develop motor neuron disease, mimicking the human disease. Neuropathologic analysis of the mice with end-stage disease revealed the accumulation of ubiquitinated inclusions in the brain and spinal cord, astrocytosis, a reduction in the number of hippocampal neurons, and reduced staining of TAR-DNA binding protein 43 in the nucleus, with concomitant formation of ubiquitin+ inclusions in the cytoplasm of spinal motor neurons. Moreover, both lines displayed denervation muscle atrophy and age-dependent loss of motor neurons that correlated with a reduction in the number of large-caliber axons. By contrast, two mouse lines expressing WT UBQLN2 were mostly devoid of clinical and pathological signs of disease. These UBQLN2 mouse models provide valuable tools for identifying the mechanisms underlying ALS-FTD pathogenesis and for investigating therapeutic strategies to halt disease.
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42
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Comparative interactomics analysis of different ALS-associated proteins identifies converging molecular pathways. Acta Neuropathol 2016; 132:175-196. [PMID: 27164932 PMCID: PMC4947123 DOI: 10.1007/s00401-016-1575-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/14/2016] [Accepted: 04/15/2016] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment available. An increasing number of genetic causes of ALS are being identified, but how these genetic defects lead to motor neuron degeneration and to which extent they affect common cellular pathways remains incompletely understood. To address these questions, we performed an interactomic analysis to identify binding partners of wild-type (WT) and ALS-associated mutant versions of ATXN2, C9orf72, FUS, OPTN, TDP-43 and UBQLN2 in neuronal cells. This analysis identified several known but also many novel binding partners of these proteins. Interactomes of WT and mutant ALS proteins were very similar except for OPTN and UBQLN2, in which mutations caused loss or gain of protein interactions. Several of the identified interactomes showed a high degree of overlap: shared binding partners of ATXN2, FUS and TDP-43 had roles in RNA metabolism; OPTN- and UBQLN2-interacting proteins were related to protein degradation and protein transport, and C9orf72 interactors function in mitochondria. To confirm that this overlap is important for ALS pathogenesis, we studied fragile X mental retardation protein (FMRP), one of the common interactors of ATXN2, FUS and TDP-43, in more detail in in vitro and in vivo model systems for FUS ALS. FMRP localized to mutant FUS-containing aggregates in spinal motor neurons and bound endogenous FUS in a direct and RNA-sensitive manner. Furthermore, defects in synaptic FMRP mRNA target expression, neuromuscular junction integrity, and motor behavior caused by mutant FUS in zebrafish embryos, could be rescued by exogenous FMRP expression. Together, these results show that interactomics analysis can provide crucial insight into ALS disease mechanisms and they link FMRP to motor neuron dysfunction caused by FUS mutations.
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Harel T, Yesil G, Bayram Y, Coban-Akdemir Z, Charng WL, Karaca E, Al Asmari A, Eldomery MK, Hunter JV, Jhangiani SN, Rosenfeld JA, Pehlivan D, El-Hattab AW, Saleh MA, LeDuc CA, Muzny D, Boerwinkle E, Gibbs RA, Chung WK, Yang Y, Belmont JW, Lupski JR. Monoallelic and Biallelic Variants in EMC1 Identified in Individuals with Global Developmental Delay, Hypotonia, Scoliosis, and Cerebellar Atrophy. Am J Hum Genet 2016; 98:562-570. [PMID: 26942288 DOI: 10.1016/j.ajhg.2016.01.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/19/2016] [Indexed: 01/08/2023] Open
Abstract
The paradigm of a single gene associated with one specific phenotype and mode of inheritance has been repeatedly challenged. Genotype-phenotype correlations can often be traced to different mutation types, localization of the variants in distinct protein domains, or the trigger of or escape from nonsense-mediated decay. Using whole-exome sequencing, we identified homozygous variants in EMC1 that segregated with a phenotype of developmental delay, hypotonia, scoliosis, and cerebellar atrophy in three families. In addition, a de novo heterozygous EMC1 variant was seen in an individual with a similar clinical and MRI imaging phenotype. EMC1 encodes a member of the endoplasmic reticulum (ER)-membrane protein complex (EMC), an evolutionarily conserved complex that has been proposed to have multiple roles in ER-associated degradation, ER-mitochondria tethering, and proper assembly of multi-pass transmembrane proteins. Perturbations of protein folding and organelle crosstalk have been implicated in neurodegenerative processes including cerebellar atrophy. We propose EMC1 as a gene in which either biallelic or monoallelic variants might lead to a syndrome including intellectual disability and preferential degeneration of the cerebellum.
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Affiliation(s)
- Tamar Harel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Gozde Yesil
- Department of Medical Genetics, Bezmialem University, Istanbul 34093, Turkey
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ali Al Asmari
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Mohammad K Eldomery
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill V Hunter
- Department of Pediatric Radiology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Miraca Genetics Laboratories, Baylor College of Medicine, Houston, TX 77030, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain 15258, United Arab Emirates
| | - Mohammed A Saleh
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Charles A LeDuc
- Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA
| | - Donna Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Human Genetics Center, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wendy K Chung
- Departments of Pediatrics and Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Miraca Genetics Laboratories, Baylor College of Medicine, Houston, TX 77030, USA
| | - John W Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston TX 77030, USA
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Picher-Martel V, Dutta K, Phaneuf D, Sobue G, Julien JP. Ubiquilin-2 drives NF-κB activity and cytosolic TDP-43 aggregation in neuronal cells. Mol Brain 2015; 8:71. [PMID: 26521126 PMCID: PMC4628361 DOI: 10.1186/s13041-015-0162-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/22/2015] [Indexed: 12/13/2022] Open
Abstract
Background Mutations in the gene encoding Ubiquilin-2 (UBQLN2) are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). UBQLN2 plays a central role in ubiquitin proteasome system (UPS) and UBQLN2 mutants can form cytoplasmic aggregates in vitro and in vivo. Results Here, we report that overexpression of WT or mutant UBQLN2 species enhanced nuclear factor κB (NF-κB) activation in Neuro2A cells. The inhibition of NF-κB stress-mediated activation with SB203580, a p38 MAPK inhibitor, demonstrated a role for MAPK in NF-κB activation by UBQLN2 species. Live cell imaging and microscopy showed that UBQLN2 aggregates are dynamic structures that promote cytoplasmic accumulation of TAR DNA-binding protein (TDP-43), a major component of ALS inclusion bodies. Furthermore, up-regulation of UBQLN2 species in neurons caused an ER-stress response and increased their vulnerability to death by toxic mediator TNF-α. Withaferin A, a known NF-κB inhibitor, reduced mortality of Neuro2A cells overexpressing UBQLN2 species. Conclusions These results suggest that UBQLN2 dysregulation in neurons can drive NF-κB activation and cytosolic TDP-43 aggregation, supporting the concept of pathway convergence in ALS pathogenesis. These Ubiquilin-2 pathogenic pathways might represent suitable therapeutic targets for future ALS treatment. Electronic supplementary material The online version of this article (doi:10.1186/s13041-015-0162-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vincent Picher-Martel
- Research Centre of Institut Universitaire en Santé Mentale de Québec, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.,Department of Psychiatry and Neuroscience, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Kallol Dutta
- Research Centre of Institut Universitaire en Santé Mentale de Québec, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.,Department of Psychiatry and Neuroscience, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Daniel Phaneuf
- Research Centre of Institut Universitaire en Santé Mentale de Québec, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.,Department of Psychiatry and Neuroscience, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho Showa-ku, Nagoya, 466-8550, Japan
| | - Jean-Pierre Julien
- Research Centre of Institut Universitaire en Santé Mentale de Québec, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada. .,Department of Psychiatry and Neuroscience, Laval University, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada.
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Ceballos-Diaz C, Rosario AM, Park HJ, Chakrabarty P, Sacino A, Cruz PE, Siemienski Z, Lara N, Moran C, Ravelo N, Golde TE, McFarland NR. Viral expression of ALS-linked ubiquilin-2 mutants causes inclusion pathology and behavioral deficits in mice. Mol Neurodegener 2015; 10:25. [PMID: 26152284 PMCID: PMC4495639 DOI: 10.1186/s13024-015-0026-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/30/2015] [Indexed: 12/14/2022] Open
Abstract
Background UBQLN2 mutations have recently been associated with familial forms of amyotrophic lateral sclerosis (ALS) and ALS-dementia. UBQLN2 encodes for ubiquilin-2, a member of the ubiquitin-like protein family which facilitates delivery of ubiquitinated proteins to the proteasome for degradation. To study the potential role of ubiquilin-2 in ALS, we used recombinant adeno-associated viral (rAAV) vectors to express UBQLN2 and three of the identified ALS-linked mutants (P497H, P497S, and P506T) in primary neuroglial cultures and in developing neonatal mouse brains. Results In primary cultures rAAV2/8-mediated expression of UBQLN2 mutants resulted in inclusion bodies and insoluble aggregates. Intracerebroventricular injection of FVB mice at post-natal day 0 with rAAV2/8 expressing wild type or mutant UBQLN2 resulted in widespread, sustained expression of ubiquilin-2 in brain. In contrast to wild type, mutant UBQLN2 expression induced significant pathology with large neuronal, cytoplasmic inclusions and ubiquilin-2-positive aggregates in surrounding neuropil. Ubiquilin-2 inclusions co-localized with ubiquitin, p62/SQSTM, optineurin, and occasionally TDP-43, but were negative for α-synuclein, neurofilament, tau, and FUS. Mutant UBLQN2 expression also resulted in Thioflavin-S-positive inclusions/aggregates. Mice expressing mutant forms of UBQLN2 variably developed a motor phenotype at 3–4 months, including nonspecific clasping and rotarod deficits. Conclusions These findings demonstrate that UBQLN2 mutants (P497H, P497S, and P506T) induce proteinopathy and cause behavioral deficits, supporting a “toxic” gain-of-function, which may contribute to ALS pathology. These data establish also that our rAAV model can be used to rapidly assess the pathological consequences of various UBQLN2 mutations and provides an agile system to further interrogate the molecular mechanisms of ubiquilins in neurodegeneration.
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Affiliation(s)
- Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Awilda M Rosario
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Hyo-Jin Park
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA.,Department of Neurology, College of Medicine, University of Florida, 1149 S Newell Dr, L3-100, PO Box 100236, Gainesville, FL, 32610, USA
| | - Paramita Chakrabarty
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Amanda Sacino
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Zoe Siemienski
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Nicolas Lara
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Corey Moran
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Natalia Ravelo
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA.,Department of Neurology, College of Medicine, University of Florida, 1149 S Newell Dr, L3-100, PO Box 100236, Gainesville, FL, 32610, USA
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA
| | - Nikolaus R McFarland
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Dr, PO Box 100159, Gainesville, FL, 32610, USA. .,Department of Neurology, College of Medicine, University of Florida, 1149 S Newell Dr, L3-100, PO Box 100236, Gainesville, FL, 32610, USA.
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46
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Chang L, Monteiro MJ. Defective Proteasome Delivery of Polyubiquitinated Proteins by Ubiquilin-2 Proteins Containing ALS Mutations. PLoS One 2015; 10:e0130162. [PMID: 26075709 PMCID: PMC4468220 DOI: 10.1371/journal.pone.0130162] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/17/2015] [Indexed: 12/14/2022] Open
Abstract
Ubiquilin proteins facilitate delivery of ubiquitinated proteins to the proteasome for degradation. Interest in the proteins has been heightened by the discovery that gene mutations in UBQLN2 cause dominant inheritance of amyotrophic lateral sclerosis (ALS). However, the mechanisms by which the mutations cause ALS are not known. Here we report on the underlying defect of ubiquilin-2 proteins containing ALS-linked mutations in affecting proteasome-mediated degradation. We found that overexpression of ubiquilin-2 proteins containing any one of five different ALS mutations slow degradation of Myc, a prototypic proteasome substrate. Examination of coprecipitating proteins indicated that the mutant proteins are generally capable of binding polyubiquitinated proteins, but defective in binding the proteasome. GST-pulldown studies revealed that many of the mutants bind weaker to the S5a subunit of the proteasome, compared with wild type (WT) ubiquilin-2 protein. The results suggest the mutant proteins are unable to deliver their captured cargo to the proteasome for degradation, which presumably leads to toxicity. Quantification of cell death is consistent with this idea. Measurement of protein turnover further indicated the mutant proteins have longer half-lives than WT ubiquilin-2. Our studies provide novel insight into the mechanism by which ALS-linked mutations in UBQLN2 interfere with protein degradation.
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Affiliation(s)
- Lydia Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Mervyn J. Monteiro
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Wu Q, Liu M, Huang C, Liu X, Huang B, Li N, Zhou H, Xia XG. Pathogenic Ubqln2 gains toxic properties to induce neuron death. Acta Neuropathol 2015; 129:417-28. [PMID: 25388785 DOI: 10.1007/s00401-014-1367-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 12/14/2022]
Abstract
Mutations in ubiquilin 2 (Ubqln2) is linked to amyotrophic lateral sclerosis and frontotemporal lobar degeneration. A foremost question regarding Ubqln2 pathogenesis is whether pathogenically mutated Ubqln2 causes neuron death via a gain or loss of functions. To better understand Ubqln2 pathobiology, we created Ubqln2 transgenic and knockout rats and compared phenotypic expression in these novel rat models. Overexpression of Ubqln2 with a pathogenic mutation (P497H substitution) caused cognitive deficits and neuronal loss in transgenic rats at the age of 130 days. In the transgenic rats, neuronal loss was preceded by the progressive formation of Ubqln2 aggregates and was accompanied by the progressive accumulation of the autophagy substrates p62 and LC3-II and the impairment of endosome pathways. In contrast, none of these pathologies observed in mutant Ubqln2 transgenic rats was detected in Ubqln2 knockout rats at the age of 300 days. Together, our findings in Ubqln2 transgenic and knockout rats collectively suggest that pathogenic Ubqln2 causes neuron death mainly through a gain of unrevealed functions rather than a loss of physiological functions.
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Affiliation(s)
- Qinxue Wu
- Department of Pathology, Thomas Jefferson University, JAH506, 1020 Locust Street, Philadelphia, PA, 19107, USA
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48
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Autophagy receptor defects and ALS-FTLD. Mol Cell Neurosci 2015; 66:43-52. [PMID: 25683489 DOI: 10.1016/j.mcn.2015.01.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/16/2015] [Accepted: 01/27/2015] [Indexed: 12/11/2022] Open
Abstract
Various pathophysiological mechanisms have been implicated in the ALS-FTLD clinicopathological spectrum of neurodegenerative disorders. Here we focus on the role of autophagy, an intracellular catabolic pathway, in these conditions. Growing evidence suggests that the autophagic process can be disturbed in ALS-FTLD, including by genetic mutations affecting autophagy receptor proteins (ubiquilin-2, optineurin, SQSTM1/p62) and regulators (VCP). Such mutations may impair clearance of autophagy substrates with pathological consequences. Recent studies have also uncovered a direct connection between autophagy and RNA processing, supporting an integrated model connecting several ALS-FTLD associated gene products. This article is part of a Special Issue entitled 'Neuronal Protein'.
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Gilpin KM, Chang L, Monteiro MJ. ALS-linked mutations in ubiquilin-2 or hnRNPA1 reduce interaction between ubiquilin-2 and hnRNPA1. Hum Mol Genet 2015; 24:2565-77. [PMID: 25616961 DOI: 10.1093/hmg/ddv020] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/21/2015] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS)-linked mutations in UBQLN2 and some members of the heterogeneous nuclear ribonucleoproteins (hnRNPs) family cause ALS. Most mutations in UBQLN2 are missense mutations that occur in and around a PXX repeat motif located in the central domain of the encoded protein. However, neither the function of the PXX motif nor the mechanism by which mutations in UBQLN2 cause ALS is known. We screened a yeast two-hybrid library using the central domain of ubiquilin-2 hoping to identify proteins whose binding is affected by the UBQLN2 mutations. Three such interactors were identified-hnRNPA1, hnRNPA3 and hnRNPU-all members of the hnRNP family. The interacting region in each of these proteins was their glycine-rich domain, the domain most frequently mutated in hnRNP-related proteins that cause ALS. We focused on hnRNPA1, because a mutation in the protein causes ALS. We confirmed the interaction between wild-type (WT) ubiquilin-2 and hnRNPA1 proteins in vitro and in cells. In contrast, all five ALS mutations in ubiquilin-2 that we examined had reduced binding with WT hnRNPA1. In addition, hnRNPA1 carrying the D262V missense mutation that causes ALS failed to bind WT ubiquilin-2. Overexpression of ubiquilin-2 containing the ALS mutations increased cell death and, for several of the mutants, this correlated with increased translocation of hnRNPA1 to the cytoplasm. Knockdown of ubiquilin-2 led to increased turnover of hnRNPA1, indicating ubiquilin-2 functions to stabilize hnRNPA1. The discovery that ubiquilin-2 interacts with hnRNP proteins and that mutation in either protein disrupts interaction suggests a connection between proteostasis and RNA metabolism.
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Affiliation(s)
- Kathleen M Gilpin
- Neuroscience Graduate Program, Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 North Pine Street, Baltimore, MD 21201, USA
| | - Lydia Chang
- Neuroscience Graduate Program, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 North Pine Street, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- Neuroscience Graduate Program, Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 North Pine Street, Baltimore, MD 21201, USA
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