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Ito M, Sugiyama A, Higuchi Y, Takashima H, Takahashi Y, Mizusawa H, Kuwabara S. Writer's Cramps as an Initial Symptom of Spinocerebellar Ataxia Type 14. Intern Med 2024; 63:2183-2186. [PMID: 38072404 DOI: 10.2169/internalmedicine.2943-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/02/2024] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is a rare form of autosomal dominant cerebellar ataxia caused by mutations in PRKCG. We herein report a case of SCA14 presenting with writer's cramp that predated the onset of progressive ataxia by four years. A 47-year-old Japanese woman had an 11-year history of writer's cramps, followed by unsteadiness. Whole-exome sequencing revealed a heterozygous mutation in PRKCG (p.C142S), leading to an SCA14 diagnosis. Therefore, writer's cramp might be a characteristic extracerebellar sign of SCA14 and can precede the onset of cerebellar ataxia.
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Affiliation(s)
- Miwa Ito
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - Atsuhiko Sugiyama
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center of Neurology and Psychiatry, Japan
| | - Hidehiro Mizusawa
- Department of Neurology, National Center of Neurology and Psychiatry, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
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2
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Costa RG, Conceição A, Matos CA, Nóbrega C. The polyglutamine protein ATXN2: from its molecular functions to its involvement in disease. Cell Death Dis 2024; 15:415. [PMID: 38877004 PMCID: PMC11178924 DOI: 10.1038/s41419-024-06812-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/16/2024]
Abstract
A CAG repeat sequence in the ATXN2 gene encodes a polyglutamine (polyQ) tract within the ataxin-2 (ATXN2) protein, showcasing a complex landscape of functions that have been progressively unveiled over recent decades. Despite significant progresses in the field, a comprehensive overview of the mechanisms governed by ATXN2 remains elusive. This multifaceted protein emerges as a key player in RNA metabolism, stress granules dynamics, endocytosis, calcium signaling, and the regulation of the circadian rhythm. The CAG overexpansion within the ATXN2 gene produces a protein with an extended poly(Q) tract, inducing consequential alterations in conformational dynamics which confer a toxic gain and/or partial loss of function. Although overexpanded ATXN2 is predominantly linked to spinocerebellar ataxia type 2 (SCA2), intermediate expansions are also implicated in amyotrophic lateral sclerosis (ALS) and parkinsonism. While the molecular intricacies await full elucidation, SCA2 presents ATXN2-associated pathological features, encompassing autophagy impairment, RNA-mediated toxicity, heightened oxidative stress, and disruption of calcium homeostasis. Presently, SCA2 remains incurable, with patients reliant on symptomatic and supportive treatments. In the pursuit of therapeutic solutions, various studies have explored avenues ranging from pharmacological drugs to advanced therapies, including cell or gene-based approaches. These endeavours aim to address the root causes or counteract distinct pathological features of SCA2. This review is intended to provide an updated compendium of ATXN2 functions, delineate the associated pathological mechanisms, and present current perspectives on the development of innovative therapeutic strategies.
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Affiliation(s)
- Rafael G Costa
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
| | - André Conceição
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), Coimbra, Portugal
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Carlos A Matos
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
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Reinhardt R, Leonard TA. A critical evaluation of protein kinase regulation by activation loop autophosphorylation. eLife 2023; 12:e88210. [PMID: 37470698 PMCID: PMC10359097 DOI: 10.7554/elife.88210] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/07/2023] [Indexed: 07/21/2023] Open
Abstract
Phosphorylation of proteins is a ubiquitous mechanism of regulating their function, localization, or activity. Protein kinases, enzymes that use ATP to phosphorylate protein substrates are, therefore, powerful signal transducers in eukaryotic cells. The mechanism of phosphoryl-transfer is universally conserved among protein kinases, which necessitates the tight regulation of kinase activity for the orchestration of cellular processes with high spatial and temporal fidelity. In response to a stimulus, many kinases enhance their own activity by autophosphorylating a conserved amino acid in their activation loop, but precisely how this reaction is performed is controversial. Classically, kinases that autophosphorylate their activation loop are thought to perform the reaction in trans, mediated by transient dimerization of their kinase domains. However, motivated by the recently discovered regulation mechanism of activation loop cis-autophosphorylation by a kinase that is autoinhibited in trans, we here review the various mechanisms of autoregulation that have been proposed. We provide a framework for critically evaluating biochemical, kinetic, and structural evidence for protein kinase dimerization and autophosphorylation, and share some thoughts on the implications of these mechanisms within physiological signaling networks.
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Affiliation(s)
- Ronja Reinhardt
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
| | - Thomas A Leonard
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
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4
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Kapfhammer JP, Shimobayashi E. Viewpoint: spinocerebellar ataxias as diseases of Purkinje cell dysfunction rather than Purkinje cell loss. Front Mol Neurosci 2023; 16:1182431. [PMID: 37426070 PMCID: PMC10323145 DOI: 10.3389/fnmol.2023.1182431] [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: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 07/11/2023] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases mostly affecting cerebellar Purkinje cells caused by a wide variety of different mutations. One subtype, SCA14, is caused by mutations of Protein Kinase C gamma (PKCγ), the dominant PKC isoform present in Purkinje cells. Mutations in the pathway in which PKCγ is active, i.e., in the regulation of calcium levels and calcium signaling in Purkinje cells, are the cause of several other variants of SCA. In SCA14, many of the observed mutations in the PKCγ gene were shown to increase the basal activity of PKCγ, raising the possibility that increased activity of PKCγ might be the cause of most forms of SCA14 and might also be involved in the pathogenesis of SCA in related subtypes. In this viewpoint and review article we will discuss the evidence for and against such a major role of PKCγ basal activity and will suggest a hypothesis of how PKCγ activity and the calcium signaling pathway may be involved in the pathogenesis of SCAs despite the different and sometimes opposing effects of mutations affecting these pathways. We will then widen the scope and propose a concept of SCA pathogenesis which is not primarily driven by cell death and loss of Purkinje cells but rather by dysfunction of Purkinje cells which are still present and alive in the cerebellum.
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Spencer-Smith R, Terrell EM, Insinna C, Agamasu C, Wagner ME, Ritt DA, Stauffer J, Stephen AG, Morrison DK. RASopathy mutations provide functional insight into the BRAF cysteine-rich domain and reveal the importance of autoinhibition in BRAF regulation. Mol Cell 2022; 82:4262-4276.e5. [PMID: 36347258 PMCID: PMC9677513 DOI: 10.1016/j.molcel.2022.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/16/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
BRAF is frequently mutated in human cancer and the RASopathy syndromes, with RASopathy mutations often observed in the cysteine-rich domain (CRD). Although the CRD participates in phosphatidylserine (PS) binding, the RAS-RAF interaction, and RAF autoinhibition, the impact of these activities on RAF function in normal and disease states is not well characterized. Here, we analyze a panel of CRD mutations and show that they increase BRAF activity by relieving autoinhibition and/or enhancing PS binding, with relief of autoinhibition being the major factor determining mutation severity. Further, we show that CRD-mediated autoinhibition prevents the constitutive plasma membrane localization of BRAF that causes increased RAS-dependent and RAS-independent function. Comparison of the BRAF- and CRAF-CRDs also indicates that the BRAF-CRD is a stronger mediator of autoinhibition and PS binding, and given the increased catalytic activity of BRAF, our studies reveal a more critical role for CRD-mediated autoinhibition in BRAF regulation.
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Affiliation(s)
- Russell Spencer-Smith
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Elizabeth M Terrell
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Christine Insinna
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Constance Agamasu
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Morgan E Wagner
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Daniel A Ritt
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Jim Stauffer
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA
| | - Andrew G Stephen
- National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA
| | - Deborah K Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA.
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6
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Liu D, Zinski A, Mishra A, Noh H, Park GH, Qin Y, Olorife O, Park JM, Abani CP, Park JS, Fung J, Sawaqed F, Coyle JT, Stahl E, Bendl J, Fullard JF, Roussos P, Zhang X, Stanton PK, Yin C, Huang W, Kim HY, Won H, Cho JH, Chung S. Impact of schizophrenia GWAS loci converge onto distinct pathways in cortical interneurons vs glutamatergic neurons during development. Mol Psychiatry 2022; 27:4218-4233. [PMID: 35701597 DOI: 10.1038/s41380-022-01654-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/24/2022] [Accepted: 05/31/2022] [Indexed: 02/07/2023]
Abstract
Remarkable advances have been made in schizophrenia (SCZ) GWAS, but gleaning biological insight from these loci is challenging. Genetic influences on gene expression (e.g., eQTLs) are cell type-specific, but most studies that attempt to clarify GWAS loci's influence on gene expression have employed tissues with mixed cell compositions that can obscure cell-specific effects. Furthermore, enriched SCZ heritability in the fetal brain underscores the need to study the impact of SCZ risk loci in specific developing neurons. MGE-derived cortical interneurons (cINs) are consistently affected in SCZ brains and show enriched SCZ heritability in human fetal brains. We identified SCZ GWAS risk genes that are dysregulated in iPSC-derived homogeneous populations of developing SCZ cINs. These SCZ GWAS loci differential expression (DE) genes converge on the PKC pathway. Their disruption results in PKC hyperactivity in developing cINs, leading to arborization deficits. We show that the fine-mapped GWAS locus in the ATP2A2 gene of the PKC pathway harbors enhancer marks by ATACseq and ChIPseq, and regulates ATP2A2 expression. We also generated developing glutamatergic neurons (GNs), another population with enriched SCZ heritability, and confirmed their functionality after transplantation into the mouse brain. Then, we identified SCZ GWAS risk genes that are dysregulated in developing SCZ GNs. GN-specific SCZ GWAS loci DE genes converge on the ion transporter pathway, distinct from those for cINs. Disruption of the pathway gene CACNA1D resulted in deficits of Ca2+ currents in developing GNs, suggesting compromised neuronal function by GWAS loci pathway deficits during development. This study allows us to identify cell type-specific and developmental stage-specific mechanisms of SCZ risk gene function, and may aid in identifying mechanism-based novel therapeutic targets.
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Affiliation(s)
- Dongxin Liu
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA.
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China.
| | - Amy Zinski
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Akanksha Mishra
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Haneul Noh
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
- Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA, 02478, USA
| | - Gun-Hoo Park
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Yiren Qin
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Oshoname Olorife
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - James M Park
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Chiderah P Abani
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Joy S Park
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Janice Fung
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Farah Sawaqed
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Joseph T Coyle
- Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA, 02478, USA
| | - Eli Stahl
- Pamela Sklar Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
| | - Jaroslav Bendl
- Pamela Sklar Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
| | - John F Fullard
- Pamela Sklar Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
| | - Panos Roussos
- Pamela Sklar Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA
- Mental Illness Research Education and Clinical Center (VISN 2 South), James J. Peters VA Medical Center, Bronx, NY, 10468, USA
| | - Xiaolei Zhang
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Patric K Stanton
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
| | - Changhong Yin
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA
| | - Weihua Huang
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA
| | - Hae-Young Kim
- Department of Public Health, New York Medical College, Valhalla, NY, USA
| | - Hyejung Won
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Jun-Hyeong Cho
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Sangmi Chung
- Department of Cell biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA.
- Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA, 02478, USA.
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Pilo CA, Baffi TR, Kornev AP, Kunkel MT, Malfavon M, Chen DH, Rossitto LA, Chen DX, Huang LC, Longman C, Kannan N, Raskind WH, Gonzalez DJ, Taylor SS, Gorrie G, Newton AC. Mutations in protein kinase Cγ promote spinocerebellar ataxia type 14 by impairing kinase autoinhibition. Sci Signal 2022; 15:eabk1147. [PMID: 36166510 PMCID: PMC9810342 DOI: 10.1126/scisignal.abk1147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Spinocerebellar ataxia type 14 (SCA14) is a neurodegenerative disease caused by germline variants in the diacylglycerol (DAG)/Ca2+-regulated protein kinase Cγ (PKCγ), leading to Purkinje cell degeneration and progressive cerebellar dysfunction. Most of the identified mutations cluster in the DAG-sensing C1 domains. Here, we found with a FRET-based activity reporter that SCA14-associated PKCγ mutations, including a previously undescribed variant, D115Y, enhanced the basal activity of the kinase by compromising its autoinhibition. Unlike other mutations in PKC that impair its autoinhibition but lead to its degradation, the C1 domain mutations protected PKCγ from such down-regulation. This enhanced basal signaling rewired the brain phosphoproteome, as revealed by phosphoproteomic analysis of cerebella from mice expressing a human SCA14-associated H101Y mutant PKCγ transgene. Mutations that induced a high basal activity in vitro were associated with earlier average age of onset in patients. Furthermore, the extent of disrupted autoinhibition, but not agonist-stimulated activity, correlated with disease severity. Molecular modeling indicated that almost all SCA14 variants not within the C1 domain were located at interfaces with the C1B domain, suggesting that mutations in and proximal to the C1B domain are a susceptibility for SCA14 because they uniquely enhance PKCγ basal activity while protecting the enzyme from down-regulation. These results provide insight into how PKCγ activation is modulated and how deregulation of the cerebellar phosphoproteome by SCA14-associated mutations affects disease progression.
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Affiliation(s)
- Caila A. Pilo
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
- Biomedical Sciences Graduate Program, University of California, La Jolla, CA 92037, USA
| | - Timothy R. Baffi
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Alexandr P. Kornev
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Maya T. Kunkel
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Mario Malfavon
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Dong-Hui Chen
- Department of Neurology, University of Washington Seattle, WA 98195, USA
| | - Leigh-Ana Rossitto
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
- Biomedical Sciences Graduate Program, University of California, La Jolla, CA 92037, USA
| | - Daniel X. Chen
- Department of Neurology, University of Washington Seattle, WA 98195, USA
| | - Liang-Chin Huang
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Cheryl Longman
- Queen Elizabeth University Hospital, Glasgow, Scotland G51 4TF, United Kingdom
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Wendy H. Raskind
- Department of Medicine/Medical Genetics, University of Washington Seattle, WA 98195, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington Seattle, WA 98195, USA
- Mental Illness Research, Education and Clinical Center, Department of Veterans Affairs, Seattle, WA 98108, USA
| | - David J. Gonzalez
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Susan S. Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - George Gorrie
- Queen Elizabeth University Hospital, Glasgow, Scotland G51 4TF, United Kingdom
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
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8
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Pilo CA, Newton AC. Two Sides of the Same Coin: Protein Kinase C γ in Cancer and Neurodegeneration. Front Cell Dev Biol 2022; 10:929510. [PMID: 35800893 PMCID: PMC9253466 DOI: 10.3389/fcell.2022.929510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/23/2022] [Indexed: 12/23/2022] Open
Abstract
Protein kinase C (PKC) isozymes transduce myriad signals within the cell in response to the generation of second messengers from membrane phospholipids. The conventional isozyme PKCγ reversibly binds Ca2+ and diacylglycerol, which leads to an open, active conformation. PKCγ expression is typically restricted to neurons, but evidence for its expression in certain cancers has emerged. PKC isozymes have been labeled as oncogenes since the discovery that they bind tumor-promoting phorbol esters, however, studies of cancer-associated PKC mutations and clinical trial data showing that PKC inhibitors have worsened patient survival have reframed PKC as a tumor suppressor. Aberrant expression of PKCγ in certain cancers suggests a role outside the brain, although whether PKCγ also acts as a tumor suppressor remains to be established. On the other hand, PKCγ variants associated with spinocerebellar ataxia type 14 (SCA14), a neurodegenerative disorder characterized by Purkinje cell degeneration, enhance basal activity while preventing phorbol ester-mediated degradation. Although the basis for SCA14 Purkinje cell degeneration remains unknown, studies have revealed how altered PKCγ activity rewires cerebellar signaling to drive SCA14. Importantly, enhanced basal activity of SCA14-associated mutants inversely correlates with age of onset, supporting that enhanced PKCγ activity drives SCA14. Thus, PKCγ activity should likely be inhibited in SCA14, whereas restoring PKC activity should be the goal in cancer therapies. This review describes how PKCγ activity can be lost or gained in disease and the overarching need for a PKC structure as a powerful tool to predict the effect of PKCγ mutations in disease.
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Affiliation(s)
- Caila A. Pilo
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, San Diego, CA, United States
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
- *Correspondence: Alexandra C. Newton,
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9
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Ghorbani F, Alimohamed MZ, Vilacha JF, Van Dijk KK, De Boer-Bergsma J, Fokkens MR, Lemmink H, Sijmons RH, Sikkema-Raddatz B, Groves MR, Verschuuren-Bemelmans CC, Verbeek DS, Van Diemen CC, Westers H. Feasibility of Follow-Up Studies and Reclassification in Spinocerebellar Ataxia Gene Variants of Unknown Significance. Front Genet 2022; 13:782685. [PMID: 35401678 PMCID: PMC8990126 DOI: 10.3389/fgene.2022.782685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Spinocerebellar ataxia (SCA) is a heterogeneous group of neurodegenerative disorders with autosomal dominant inheritance. Genetic testing for SCA leads to diagnosis, prognosis and risk assessment for patients and their family members. While advances in sequencing and computing technologies have provided researchers with a rapid expansion in the genetic test content that can be used to unravel the genetic causes that underlie diseases, the large number of variants with unknown significance (VUSes) detected represent challenges. To minimize the proportion of VUSes, follow-up studies are needed to aid in their reclassification as either (likely) pathogenic or (likely) benign variants. In this study, we addressed the challenge of prioritizing VUSes for follow-up using (a combination of) variant segregation studies, 3D protein modeling, in vitro splicing assays and functional assays. Of the 39 VUSes prioritized for further analysis, 13 were eligible for follow up. We were able to reclassify 4 of these VUSes to LP, increasing the molecular diagnostic yield by 1.1%. Reclassification of VUSes remains difficult due to limited possibilities for performing variant segregation studies in the classification process and the limited availability of routine functional tests.
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Affiliation(s)
- Fatemeh Ghorbani
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Mohamed Z. Alimohamed
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
- Shree Hindu Mandal Hospital, Dar es Salaam, Tanzania
| | - Juliana F. Vilacha
- Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Krista K. Van Dijk
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Jelkje De Boer-Bergsma
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Michiel R. Fokkens
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Henny Lemmink
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Rolf H. Sijmons
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Birgit Sikkema-Raddatz
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Matthew R. Groves
- Structural Biology in Drug Design, Department of Drug Design, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
| | | | - Dineke S. Verbeek
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- *Correspondence: Dineke S. Verbeek,
| | - Cleo C. Van Diemen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Helga Westers
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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10
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Aslam N, Alvi F. TRPC3 Channel Activity and Viability of Purkinje Neurons can be Regulated by a Local Signalosome. Front Mol Biosci 2022; 9:818682. [PMID: 35265671 PMCID: PMC8899209 DOI: 10.3389/fmolb.2022.818682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/03/2022] [Indexed: 11/19/2022] Open
Abstract
Canonical transient receptor potential channels (TRPC3) may play a pivotal role in the development and viability of dendritic arbor in Purkinje neurons. This is a novel postsynaptic channel for glutamatergic synaptic transmission. In the cerebellum, TRPC3 appears to regulate functions relating to motor coordination in a highly specific manner. Gain of TRPC3 function is linked to significant alterations in the density and connectivity of dendritic arbor in Purkinje neurons. TRPC3 signals downstream of class I metabotropic glutamate receptors (mGluR1). Moreover, diacylglycerol (DAG) can directly bind and activate TRPC3 molecules. Here, we investigate a key question: How can the activity of the TRPC3 channel be regulated in Purkinje neurons? We also explore how mGluR1 activation, Ca2+ influx, and DAG homeostasis in Purkinje neurons can be linked to TRPC3 activity modulation. Through systems biology approach, we show that TRPC3 activity can be modulated by a Purkinje cell (PC)–specific local signalosome. The assembly of this signalosome is coordinated by DAG generation after mGluR1 activation. Our results also suggest that purinergic receptor activation leads to the spatial and temporal organization of the TRPC3 signaling module and integration of its key effector molecules such as DAG, PKCγ, DGKγ, and Ca2+ into an organized local signalosome. This signaling machine can regulate the TRPC3 cycling between active, inactive, and desensitized states. Precise activity of the TRPC3 channel is essential for tightly regulating the Ca2+ entry into PCs and thus the balance of lipid and Ca2+ signaling in Purkinje neurons and hence their viability. Cell-type–specific understanding of mechanisms regulating TRPC3 channel activity could be key in identifying therapeutic targeting opportunities.
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Affiliation(s)
- Naveed Aslam
- BioSystOmics, Houston, TX, United States
- *Correspondence: Naveed Aslam,
| | - Farah Alvi
- BioSystOmics, Houston, TX, United States
- Department of Physics, COMSATS University Islamabad, Lahore Campus, Pakistan
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11
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Lordén G, Newton A. Conventional protein kinase C in the brain: repurposing cancer drugs for neurodegenerative treatment? Neuronal Signal 2021; 5:NS20210036. [PMID: 34737895 PMCID: PMC8536831 DOI: 10.1042/ns20210036] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/23/2022] Open
Abstract
Protein Kinase C (PKC) isozymes are tightly regulated kinases that transduce a myriad of signals from receptor-mediated hydrolysis of membrane phospholipids. They play an important role in brain physiology, and dysregulation of PKC activity is associated with neurodegeneration. Gain-of-function mutations in PKCα are associated with Alzheimer's disease (AD) and mutations in PKCγ cause spinocerebellar ataxia (SCA) type 14 (SCA14). This article presents an overview of the role of the conventional PKCα and PKCγ in neurodegeneration and proposes repurposing PKC inhibitors, which failed in clinical trials for cancer, for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Gema Lordén
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, U.S.A
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12
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Schmitz-Hübsch T, Lux S, Bauer P, Brandt AU, Schlapakow E, Greschus S, Scheel M, Gärtner H, Kirlangic ME, Gras V, Timmann D, Synofzik M, Giorgetti A, Carloni P, Shah JN, Schöls L, Kopp U, Bußenius L, Oberwahrenbrock T, Zimmermann H, Pfueller C, Kadas EM, Rönnefarth M, Grosch AS, Endres M, Amunts K, Paul F, Doss S, Minnerop M. Spinocerebellar ataxia type 14: refining clinicogenetic diagnosis in a rare adult-onset disorder. Ann Clin Transl Neurol 2021; 8:774-789. [PMID: 33739604 PMCID: PMC8045942 DOI: 10.1002/acn3.51315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/29/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022] Open
Abstract
Objectives Genetic variant classification is a challenge in rare adult‐onset disorders as in SCA‐PRKCG (prior spinocerebellar ataxia type 14) with mostly private conventional mutations and nonspecific phenotype. We here propose a refined approach for clinicogenetic diagnosis by including protein modeling and provide for confirmed SCA‐PRKCG a comprehensive phenotype description from a German multi‐center cohort, including standardized 3D MR imaging. Methods This cross‐sectional study prospectively obtained neurological, neuropsychological, and brain imaging data in 33 PRKCG variant carriers. Protein modeling was added as a classification criterion in variants of uncertain significance (VUS). Results Our sample included 25 cases confirmed as SCA‐PRKCG (14 variants, thereof seven novel variants) and eight carriers of variants assigned as VUS (four variants) or benign/likely benign (two variants). Phenotype in SCA‐PRKCG included slowly progressive ataxia (onset at 4–50 years), preceded in some by early‐onset nonprogressive symptoms. Ataxia was often combined with action myoclonus, dystonia, or mild cognitive‐affective disturbance. Inspection of brain MRI revealed nonprogressive cerebellar atrophy. As a novel finding, a previously not described T2 hyperintense dentate nucleus was seen in all SCA‐PRKCG cases but in none of the controls. Interpretation In this largest cohort to date, SCA‐PRKCG was characterized as a slowly progressive cerebellar syndrome with some clinical and imaging features suggestive of a developmental disorder. The observed non‐ataxia movement disorders and cognitive‐affective disturbance may well be attributed to cerebellar pathology. Protein modeling emerged as a valuable diagnostic tool for variant classification and the newly described T2 hyperintense dentate sign could serve as a supportive diagnostic marker of SCA‐PRKCG.
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Affiliation(s)
- Tanja Schmitz-Hübsch
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Silke Lux
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,CENTOGENE AG, Rostock, Germany
| | - Alexander U Brandt
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Department of Neurology, University of California, Irvine, CA, USA
| | - Elena Schlapakow
- Department of Neurology, University Hospital Bonn, Bonn, Germany.,Center for Rare Diseases, University of Bonn, Bonn, Germany
| | - Susanne Greschus
- Department of Radiology, University Hospital Bonn, Bonn, Germany
| | - Michael Scheel
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Department of Neuroradiology, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Hanna Gärtner
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany
| | - Mehmet E Kirlangic
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Institute for Biomedical Engineering and Computer Science, Technische Universität Ilmenau, Ilmenau, Germany
| | - Vincent Gras
- Institute of Neuroscience and Medicine (INM-4), Research Centre Juelich, Juelich, Germany
| | - Dagmar Timmann
- Department of Neurology, Essen University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Center for Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Alejandro Giorgetti
- Computational Biophysics, German Research School for Simulation Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, Juelich, Germany.,Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences, and Computational Biomedicine, Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Research Centre Juelich, Juelich, Germany
| | - Jon N Shah
- Institute of Neuroscience and Medicine (INM-4), Research Centre Juelich, Juelich, Germany.,Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany
| | - Ludger Schöls
- Department of Neurodegenerative Diseases, Center for Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Ute Kopp
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Lisa Bußenius
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Institute for Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Clinic Hamburg Eppendorf, Hamburg, Germany
| | - Timm Oberwahrenbrock
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Hanna Zimmermann
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Caspar Pfueller
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Ella-Maria Kadas
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany
| | - Maria Rönnefarth
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Anne-Sophie Grosch
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Matthias Endres
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Center for Stroke Research Berlin (CSB), Charité - Universitätsmedizin Berlin, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.,German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,C. and O. Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health Berlin, Berlin, Germany.,Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Sarah Doss
- Klinik und Hochschulambulanz für Neurologie, Charité -Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Movement Disorders Section, Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Martina Minnerop
- Institute of Neuroscience and Medicine (INM-1), Research Centre Juelich, Juelich, Germany.,Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.,Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
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13
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Kanda Y, Satoh R, Takasaki T, Tomimoto N, Tsuchiya K, Tsai CA, Tanaka T, Kyomoto S, Hamada K, Fujiwara T, Sugiura R. Sequestration of the PKC ortholog Pck2 in stress granules as a feedback mechanism of MAPK signaling in fission yeast. J Cell Sci 2021; 134:224095. [PMID: 33277379 DOI: 10.1242/jcs.250191] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/23/2020] [Indexed: 12/22/2022] Open
Abstract
Protein kinase C (PKC) signaling is a highly conserved signaling module that plays a central role in a myriad of physiological processes, ranging from cell proliferation to cell death, via various signaling pathways, including MAPK signaling. Stress granules (SGs) are non-membranous cytoplasmic foci that aggregate in cells exposed to environmental stresses. Here, we explored the role of SGs in PKC/MAPK signaling activation in fission yeast. High-heat stress (HHS) induced Pmk1 MAPK activation and Pck2 translocation from the cell tips into poly(A)-binding protein (Pabp)-positive SGs. Pck2 dispersal from the cell tips required Pck2 kinase activity, and constitutively active Pck2 exhibited increased translocation to SGs. Importantly, Pmk1 deletion impaired Pck2 recruitment to SGs, indicating that MAPK activation stimulates Pck2 SG translocation. Consistently, HHS-induced SGs delayed Pck2 relocalization at the cell tips, thereby blocking subsequent Pmk1 reactivation after recovery from HHS. HHS partitioned Pck2 into the Pabp-positive SG-containing fraction, which resulted in reduced Pck2 abundance and kinase activity in the soluble fraction. Taken together, these results indicate that MAPK-dependent Pck2 SG recruitment serves as a feedback mechanism to intercept PKC/MAPK activation induced by HHS, which might underlie PKC-related diseases.
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Affiliation(s)
- Yuki Kanda
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Ryosuke Satoh
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Teruaki Takasaki
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Naofumi Tomimoto
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Kiko Tsuchiya
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Chun An Tsai
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Taemi Tanaka
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Shu Kyomoto
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Kozo Hamada
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Toshinobu Fujiwara
- Laboratory of Biochemistry, Department of Pharmacy, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University, Osaka 577-8502, Japan
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14
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A New Mouse Model Related to SCA14 Carrying a Pseudosubstrate Domain Mutation in PKCγ Shows Perturbed Purkinje Cell Maturation and Ataxic Motor Behavior. J Neurosci 2021; 41:2053-2068. [PMID: 33478986 PMCID: PMC7939089 DOI: 10.1523/jneurosci.1946-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 01/12/2021] [Accepted: 01/12/2021] [Indexed: 01/15/2023] Open
Abstract
Spinocerebellar ataxias (SCAs) are diseases characterized by cerebellar atrophy and loss of Purkinje neurons caused by mutations in diverse genes. In SCA14, the disease is caused by point mutations or small deletions in protein kinase C γ (PKCγ), a crucial signaling protein in Purkinje cells. It is still unclear whether increased or decreased PKCγ activity may be involved in the SCA14 pathogenesis. In this study, we present a new knock-in mouse model related to SCA14 with a point mutation in the pseudosubstrate domain, PKCγ-A24E, known to induce a constitutive PKCγ activation. In this protein conformation, the kinase domain of PKCγ is activated, but at the same time the protein is subject to dephosphorylation and protein degradation. As a result, we find a dramatic reduction of PKCγ protein expression in PKCγ-A24E mice of either sex. Despite this reduction, there is clear evidence for an increased PKC activity in Purkinje cells from PKCγ-A24E mice. Purkinje cells derived from PKCγ-A24E have short thickened dendrites typical for PKC activation. These mice also develop a marked ataxia and signs of Purkinje cell dysfunction making them an interesting new mouse model related to SCA. Recently, a similar mutation in a human patient was discovered and found to be associated with overt SCA14. RNA profiling of PKCγ-A24E mice showed a dysregulation of related signaling pathways, such as mGluR1 or mTOR. Our results show that the induction of PKCγ activation in Purkinje cells results in the SCA-like phenotype indicating PKC activation as one pathogenetic avenue leading to a SCA.SIGNIFICANCE STATEMENT Spinocerebellar ataxias (SCAs) are hereditary diseases affecting cerebellar Purkinje cells and are a one of neurodegenerative diseases. While mutation in several genes have been identified as causing SCAs, it is unclear how these mutations cause the disease phenotype. Mutations in PKCγ cause one subtype of SCAs, SCA14. In this study, we have generated a knock-in mouse with a mutation in the pseudosubstrate domain of PKCγ, which keeps PKCγ in the constitutive active open conformation. We show that this mutation leading to a constant activation of PKCγ results in a SCA-like phenotype in these mice. Our findings establish the constant activation of PKC signaling as one pathogenetic avenue leading to an SCA phenotype and a mechanism causing a neurodegenerative disease.
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15
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Liput DJ, Nguyen TA, Augustin SM, Lee JO, Vogel SS. A Guide to Fluorescence Lifetime Microscopy and Förster's Resonance Energy Transfer in Neuroscience. CURRENT PROTOCOLS IN NEUROSCIENCE 2020; 94:e108. [PMID: 33232577 PMCID: PMC8274369 DOI: 10.1002/cpns.108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fluorescence lifetime microscopy (FLIM) and Förster's resonance energy transfer (FRET) are advanced optical tools that neuroscientists can employ to interrogate the structure and function of complex biological systems in vitro and in vivo using light. In neurobiology they are primarily used to study protein-protein interactions, to study conformational changes in protein complexes, and to monitor genetically encoded FRET-based biosensors. These methods are ideally suited to optically monitor changes in neurons that are triggered optogenetically. Utilization of this technique by neuroscientists has been limited, since a broad understanding of FLIM and FRET requires familiarity with the interactions of light and matter on a quantum mechanical level, and because the ultra-fast instrumentation used to measure fluorescent lifetimes and resonance energy transfer are more at home in a physics lab than in a biology lab. In this overview, we aim to help neuroscientists overcome these obstacles and thus feel more comfortable with the FLIM-FRET method. Our goal is to aid researchers in the neuroscience community to achieve a better understanding of the fundamentals of FLIM-FRET and encourage them to fully leverage its powerful ability as a research tool. Published 2020. U.S. Government.
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Affiliation(s)
- Daniel J. Liput
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
- Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Tuan A. Nguyen
- Laboratory of Biophotonics and Quantum Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Shana M. Augustin
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Jeong Oen Lee
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
| | - Steven S. Vogel
- Laboratory of Biophotonics and Quantum Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland
- Corresponding author:
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16
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Aslam N, Alvi F. Simplified Model of PKCγ Signaling Dysregulation and Cytosol-to-Membrane Translocation Kinetics During Neurodegenerative Spinocerebellar Ataxia Type 14 (SCA14). Front Neurosci 2020; 13:1397. [PMID: 32082104 PMCID: PMC7004970 DOI: 10.3389/fnins.2019.01397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/11/2019] [Indexed: 11/13/2022] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is an autosomal neurodegenerative disease clinically characterized by progressive ataxia in the patient's gait, accompanied by slurred speech and abnormal eye movements. These symptoms are linked to the loss of Purkinje cells (PCs), which leads to cerebellar neurodegeneration. PC observations link the mutations in PRKCG gene encoding protein kinase C γ (PKCγ) to SCA14. Observations also show that the link between PKCγ and SCA14 relies on a gain-of-function mechanism, and, in fact, both positive and negative regulation of PKCγ expression and activity may result in changes in cellular number, size, and complexity of the dendritic arbors in PCs. Here, through a systems biology approach, we investigate a key question relating to this system: why is PKCγ membrane residence time reduced in SCA14 mutant PCs compared to wild-type (WT) PCs? In this study, we investigate this question through two contrasting PKCγ signaling models in PCs. The first model proposed in this study describes the mechanism through which PKCγ signaling activity may be regulated in WT PCs. In contrast, the second model explores how mutations in PKCγ signaling affect the state of SCA14 in PCs. Numerical simulations of both models show that, in response to extracellular stimuli-induced depolarization of the membrane compartment, PKCγ and diacylglycerol kinase γ (DGKγ) translocate to the membrane. Results from our computational approach indicate that, for the same set of parameters, PKCγ membrane residence time is shorter in the SCA14 mutant model compared to the WT model. These results show how PKCγ membrane residence time is regulated by diacylglycerol (DAG), causing translocated PKCγ to return to the cytosol as DAG levels drop. This study shows that, when the strength of the extracellular signal is held constant, the membrane lifetime of mutant PKCγ is reduced. This reduction is due to the presence of constitutively active mutant PKCγ in the cytosol. Cytosolic PKCγ, in turn, leads to phosphorylation and activation of DGKγ while it is still residing in the cytosol. This effect occurs even during the resting conditions. Thus, the SCA14 mutant model explains that, when both DAG effector molecules are active in the cytosol, their interactions in the membrane compartment are reduced, critically influencing PKCγ membrane residence time.
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Affiliation(s)
- Naveed Aslam
- BioSystOmics, Bellaire, TX, United States
- Department of Chemistry and Chemical Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Farah Alvi
- BioSystOmics, Bellaire, TX, United States
- Department of Physics, COMSATS University Islamabad, Islamabad, Pakistan
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17
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Prestori F, Moccia F, D’Angelo E. Disrupted Calcium Signaling in Animal Models of Human Spinocerebellar Ataxia (SCA). Int J Mol Sci 2019; 21:ijms21010216. [PMID: 31892274 PMCID: PMC6981692 DOI: 10.3390/ijms21010216] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/22/2019] [Accepted: 12/24/2019] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) constitute a heterogeneous group of more than 40 autosomal-dominant genetic and neurodegenerative diseases characterized by loss of balance and motor coordination due to dysfunction of the cerebellum and its efferent connections. Despite a well-described clinical and pathological phenotype, the molecular and cellular events that underlie neurodegeneration are still poorly undaerstood. Emerging research suggests that mutations in SCA genes cause disruptions in multiple cellular pathways but the characteristic SCA pathogenesis does not begin until calcium signaling pathways are disrupted in cerebellar Purkinje cells. Ca2+ signaling in Purkinje cells is important for normal cellular function as these neurons express a variety of Ca2+ channels, Ca2+-dependent kinases and phosphatases, and Ca2+-binding proteins to tightly maintain Ca2+ homeostasis and regulate physiological Ca2+-dependent processes. Abnormal Ca2+ levels can activate toxic cascades leading to characteristic death of Purkinje cells, cerebellar atrophy, and ataxia that occur in many SCAs. The output of the cerebellar cortex is conveyed to the deep cerebellar nuclei (DCN) by Purkinje cells via inhibitory signals; thus, Purkinje cell dysfunction or degeneration would partially or completely impair the cerebellar output in SCAs. In the absence of the inhibitory signal emanating from Purkinje cells, DCN will become more excitable, thereby affecting the motor areas receiving DCN input and resulting in uncoordinated movements. An outstanding advantage in studying the pathogenesis of SCAs is represented by the availability of a large number of animal models which mimic the phenotype observed in humans. By mainly focusing on mouse models displaying mutations or deletions in genes which encode for Ca2+ signaling-related proteins, in this review we will discuss the several pathogenic mechanisms related to deranged Ca2+ homeostasis that leads to significant Purkinje cell degeneration and dysfunction.
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Affiliation(s)
- Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy;
- Correspondence:
| | - Francesco Moccia
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, 27100 Pavia, Italy;
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy;
- IRCCS Mondino Foundation, 27100 Pavia, Italy
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18
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Egorova PA, Bezprozvanny IB. Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2. Neurotherapeutics 2019; 16:1050-1073. [PMID: 31435879 PMCID: PMC6985344 DOI: 10.1007/s13311-019-00777-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The effective therapeutic treatment and the disease-modifying therapy for spinocerebellar ataxia type 2 (SCA2) (a progressive hereditary disease caused by an expansion of polyglutamine in the ataxin-2 protein) is not available yet. At present, only symptomatic treatment and methods of palliative care are prescribed to the patients. Many attempts were made to study the physiological, molecular, and biochemical changes in SCA2 patients and in a variety of the model systems to find new therapeutic targets for SCA2 treatment. A better understanding of the uncovered molecular mechanisms of the disease allowed the scientific community to develop strategies of potential therapy and helped to create some promising therapeutic approaches for SCA2 treatment. Recent progress in this field will be discussed in this review article.
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Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, 195251, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, 195251, Russia.
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, ND12.200, Dallas, Texas, 75390, USA.
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19
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Spinocerebellar ataxia type 14 caused by a nonsense mutation in the PRKCG gene. Mol Cell Neurosci 2019; 98:46-53. [PMID: 31158466 DOI: 10.1016/j.mcn.2019.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/25/2019] [Accepted: 05/30/2019] [Indexed: 12/15/2022] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disorder characterized by cerebellar ataxia with myoclonus, dystonia, spasticity, and rigidity. Although missense mutations and a deletion mutation have been found in the protein kinase C gamma (PRKCG) gene encoding protein kinase C γ (PKCγ) in SCA14 families, a nonsense mutation has not been reported. The patho-mechanisms underlying SCA14 remain poorly understood. However, gain-of-function mechanisms and loss-of-function mechanisms, but not dominant negative mechanisms, were reported the patho-mechanism of SCA14. We identified the c.226C>T mutation of PRKCG, which caused the p.R76X in PKCγ by whole-exome sequencing in patients presenting cerebellar atrophy with cognitive and hearing impairment. To investigate the patho-mechanism of our case, we studied aggregation formation, cell death, and PKC inhibitory effect by confocal microscopy, western blotting with cleaved caspase 3, and pSer PKC motif antibodies, respectively. PKCγ(R76X)-GFP have aggregations the same as wild-type (WT) PKCγ-GFP. The PKCγ(R76X)-GFP inhibited PKC phosphorylation activity more than GFP alone. It also induced more apoptosis in COS7 and SH-SY5Y cells compared to WT-PKCγ-GFP and GFP. We first reported SCA14 patients with p.R76X in PKCγ who have cerebellar atrophy with cognitive and hearing impairment. Our results suggest that a dominant negative mechanism due to truncated peptides produced by p.R76X may be at least partially responsible for the cerebellar atrophy.
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20
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Abstract
Protein kinase C (PKC) isozymes belong to a family of Ser/Thr kinases whose activity is governed by reversible release of an autoinhibitory pseudosubstrate. For conventional and novel isozymes, this is effected by binding the lipid second messenger, diacylglycerol, but for atypical PKC isozymes, this is effected by binding protein scaffolds. PKC shot into the limelight following the discovery in the 1980s that the diacylglycerol-sensitive isozymes are "receptors" for the potent tumor-promoting phorbol esters. This set in place a concept that PKC isozymes are oncoproteins. Yet three decades of cancer clinical trials targeting PKC with inhibitors failed and, in some cases, worsened patient outcome. Emerging evidence from cancer-associated mutations and protein expression levels provide a reason: PKC isozymes generally function as tumor suppressors and their activity should be restored, not inhibited, in cancer therapies. And whereas not enough activity is associated with cancer, variants with enhanced activity are associated with degenerative diseases such as Alzheimer's disease. This review describes the tightly controlled mechanisms that ensure PKC activity is perfectly balanced and what happens when these controls are deregulated. PKC isozymes serve as a paradigm for the wisdom of Confucius: "to go beyond is as wrong as to fall short."
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Affiliation(s)
- Alexandra C Newton
- a Department of Pharmacology , University of California at San Diego , La Jolla , CA , USA
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21
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Shimobayashi E, Kapfhammer JP. Calcium Signaling, PKC Gamma, IP3R1 and CAR8 Link Spinocerebellar Ataxias and Purkinje Cell Dendritic Development. Curr Neuropharmacol 2018; 16:151-159. [PMID: 28554312 PMCID: PMC5883377 DOI: 10.2174/1570159x15666170529104000] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/16/2017] [Accepted: 05/25/2017] [Indexed: 01/05/2023] Open
Abstract
Background Spinocerebellar ataxias (SCAs) are a group of cerebellar diseases characterized by progressive ataxia and cerebellar atrophy. Several forms of SCAs are caused by missense mutations or deletions in genes related to calcium signaling in Purkinje cells. Among them, spinocerebellar ataxia type 14 (SCA14) is caused by missense mutations in PRKCG gene which encodes protein kinase C gamma (PKCγ). It is remarkable that in several cases in which SCA is caused by point mutations in an individual gene, the affected genes are involved in the PKCγ signaling pathway and calcium signaling which is not only crucial for proper Purkinje cell function but is also involved in the control of Purkinje cell dendritic development. In this review, we will focus on the PKCγ signaling related genes and calcium signaling related genes then discuss their role for both Purkinje cell dendritic development and cerebellar ataxia. Methods Research related to SCAs and Purkinje cell dendritic development is reviewed. Results PKCγ dysregulation causes abnormal Purkinje cell dendritic development and SCA14. Carbonic anhydrase related protein 8 (Car8) encoding CAR8 and Itpr1 encoding IP3R1were identified as upregulated genes in one of SCA14 mouse model. IP3R1, CAR8 and PKCγ proteins are strongly and specifically expressed in Purkinje cells. The common function among them is that they are involved in the regulation of calcium homeostasis in Purkinje cells and their dysfunction causes ataxia in mouse and human. Furthermore, disruption of intracellular calcium homeostasis caused by mutations in some calcium channels in Purkinje cells links to abnormal Purkinje cell dendritic development and the pathogenesis of several SCAs. Conclusion Once PKCγ signaling related genes and calcium signaling related genes are disturbed, the normal dendritic development of Purkinje cells is impaired as well as the integration of signals from other neurons, resulting in abnormal development, cerebellar dysfunction and eventually Purkinje cell loss.
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Affiliation(s)
- Etsuko Shimobayashi
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, CH-4056 Basel, Switzerland
| | - Josef P Kapfhammer
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, CH-4056 Basel, Switzerland
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22
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Wong MMK, Hoekstra SD, Vowles J, Watson LM, Fuller G, Németh AH, Cowley SA, Ansorge O, Talbot K, Becker EBE. Neurodegeneration in SCA14 is associated with increased PKCγ kinase activity, mislocalization and aggregation. Acta Neuropathol Commun 2018; 6:99. [PMID: 30249303 PMCID: PMC6151931 DOI: 10.1186/s40478-018-0600-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 01/30/2023] Open
Abstract
Spinocerebellar ataxia type 14 (SCA14) is a subtype of the autosomal dominant cerebellar ataxias that is characterized by slowly progressive cerebellar dysfunction and neurodegeneration. SCA14 is caused by mutations in the PRKCG gene, encoding protein kinase C gamma (PKCγ). Despite the identification of 40 distinct disease-causing mutations in PRKCG, the pathological mechanisms underlying SCA14 remain poorly understood. Here we report the molecular neuropathology of SCA14 in post-mortem cerebellum and in human patient-derived induced pluripotent stem cells (iPSCs) carrying two distinct SCA14 mutations in the C1 domain of PKCγ, H36R and H101Q. We show that endogenous expression of these mutations results in the cytoplasmic mislocalization and aggregation of PKCγ in both patient iPSCs and cerebellum. PKCγ aggregates were not efficiently targeted for degradation. Moreover, mutant PKCγ was found to be hyper-activated, resulting in increased substrate phosphorylation. Together, our findings demonstrate that a combination of both, loss-of-function and gain-of-function mechanisms are likely to underlie the pathogenesis of SCA14, caused by mutations in the C1 domain of PKCγ. Importantly, SCA14 patient iPSCs were found to accurately recapitulate pathological features observed in post-mortem SCA14 cerebellum, underscoring their potential as relevant disease models and their promise as future drug discovery tools.
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Affiliation(s)
- Maggie M. K. Wong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Road, Oxford, OX1 3PT UK
| | - Stephanie D. Hoekstra
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Road, Oxford, OX1 3PT UK
| | - Jane Vowles
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE UK
| | - Lauren M. Watson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Road, Oxford, OX1 3PT UK
| | - Geraint Fuller
- Gloucestershire Hospitals, NHS Foundation Trust, Cheltenham General Hospital, Sandford Road, Cheltenham, GL53 7AN UK
| | - Andrea H. Németh
- Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU UK
- Oxford Centre for Genomic Medicine, ACE Building, Oxford University Hospitals NHS Trust, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7HE UK
| | - Sally A. Cowley
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE UK
| | - Olaf Ansorge
- Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford, OX3 9DU UK
| | - Esther B. E. Becker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Road, Oxford, OX1 3PT UK
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23
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Huang M, Verbeek DS. Why do so many genetic insults lead to Purkinje Cell degeneration and spinocerebellar ataxia? Neurosci Lett 2018; 688:49-57. [PMID: 29421540 DOI: 10.1016/j.neulet.2018.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/02/2018] [Indexed: 12/29/2022]
Abstract
The genetically heterozygous spinocerebellar ataxias are all characterized by cerebellar atrophy and pervasive Purkinje Cell degeneration. Up to date, more than 35 functionally diverse spinocerebellar ataxia genes have been identified. The main question that remains yet unsolved is why do some many genetic insults lead to Purkinje Cell degeneration and spinocerebellar ataxia? To address this question it is important to identify intrinsic pathways important for Purkinje Cell function and survival. In this review, we discuss the current consensus on shared mechanisms underlying the pervasive Purkinje Cell loss in spinocerebellar ataxia. Additionally, using recently published cell type specific expression data, we identified several Purkinje Cell-specific genes and discuss how the corresponding pathways might underlie the vulnerability of Purkinje Cells in response to the diverse genetic insults causing spinocerebellar ataxia.
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Affiliation(s)
- Miaozhen Huang
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Dineke S Verbeek
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.
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24
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Zhang Y, Xu J, Zhu X. A 63 signature genes prediction system is effective for glioblastoma prognosis. Int J Mol Med 2018; 41:2070-2078. [PMID: 29393370 PMCID: PMC5810221 DOI: 10.3892/ijmm.2018.3422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 01/10/2018] [Indexed: 12/31/2022] Open
Abstract
The present study aimed to explore possible prognostic marker genes in glioblastoma (GBM). Differentially expressed genes (DEGs) were screened by comparing microarray data of tumor and normal tissue samples from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) dataset GSE22866. Subsequently, the prognosis-associated DEGs were screened via Cox regression analysis, followed by construction of gene/protein/pathway interaction networks of these DEGs by calculating the correlation coefficient between the DEGs. Next, a prognostic prediction system was constructed using Bayes discriminant analysis, which was validated by the microarray data of samples from patients with good and bad prognosis from the TCGA and Chinese Glioma Genome Atlas (CGGA), as well as the GEO dataset. Finally, a co-expression network of the signature genes in the prediction system was constructed in combination with the significant pathways. A total of 288 overlapping DEGs (false discovery rate <0.5 and |log2 of fold change|>1) were screened, 123 of which were identified to be associated with the prognosis of GBM patients. The co-expression network of these prognosis-associated DEGs included 1405 interactions and 112 DEGs, and 6 functional modules were identified in the network. The prognostic prediction system was comprised of 63 signature genes with a specificity value of 0.929 and a sensitivity value of 0.948. GBM samples with good and bad prognosis in the TCGA, CGGA and GEO datasets were distinguishable by these signature genes (P=1.33×10−6, 1.63×10−4 and 0.00534, respectively). The co-expression network of signature genes with significant pathways was comprised of 56 genes and 361 interactions. Protein kinase Cγ (PRKCG), protein kinase Cβ (PRKCB) and calcium/calmodulin-dependent protein kinase IIα (CAMK2A) were important genes in the network, and based on the expression of these genes, it was possible to distinguish between samples with significantly different survival risks. In the present study, an effective prognostic prediction system for GBM patients was constructed and validated. PRKCG, PRKCB and CAMK2A may be potential prognostic factors for GBM.
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Affiliation(s)
- Yang Zhang
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Jiaming Xu
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
| | - Xiangdong Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, P.R. China
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25
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Nibbeling EAR, Duarri A, Verschuuren-Bemelmans CC, Fokkens MR, Karjalainen JM, Smeets CJLM, de Boer-Bergsma JJ, van der Vries G, Dooijes D, Bampi GB, van Diemen C, Brunt E, Ippel E, Kremer B, Vlak M, Adir N, Wijmenga C, van de Warrenburg BPC, Franke L, Sinke RJ, Verbeek DS. Exome sequencing and network analysis identifies shared mechanisms underlying spinocerebellar ataxia. Brain 2017; 140:2860-2878. [PMID: 29053796 DOI: 10.1093/brain/awx251] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 08/05/2017] [Indexed: 12/17/2022] Open
Abstract
The autosomal dominant cerebellar ataxias, referred to as spinocerebellar ataxias in genetic nomenclature, are a rare group of progressive neurodegenerative disorders characterized by loss of balance and coordination. Despite the identification of numerous disease genes, a substantial number of cases still remain without a genetic diagnosis. Here, we report five novel spinocerebellar ataxia genes, FAT2, PLD3, KIF26B, EP300, and FAT1, identified through a combination of exome sequencing in genetically undiagnosed families and targeted resequencing of exome candidates in a cohort of singletons. We validated almost all genes genetically, assessed damaging effects of the gene variants in cell models and further consolidated a role for several of these genes in the aetiology of spinocerebellar ataxia through network analysis. Our work links spinocerebellar ataxia to alterations in synaptic transmission and transcription regulation, and identifies these as the main shared mechanisms underlying the genetically diverse spinocerebellar ataxia types.
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Affiliation(s)
- Esther A R Nibbeling
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Anna Duarri
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Michiel R Fokkens
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Juha M Karjalainen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Cleo J L M Smeets
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jelkje J de Boer-Bergsma
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gerben van der Vries
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dennis Dooijes
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Giovana B Bampi
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Cleo van Diemen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ewout Brunt
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Elly Ippel
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Berry Kremer
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Monique Vlak
- Department of Neurology, Medical Center Haaglanden and Bronovo-Nebo, Den Hague, The Netherlands
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Israel
| | - Cisca Wijmenga
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Lude Franke
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Richard J Sinke
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Dineke S Verbeek
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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26
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A Calcium- and Diacylglycerol-Stimulated Protein Kinase C (PKC), Caenorhabditis elegans PKC-2, Links Thermal Signals to Learned Behavior by Acting in Sensory Neurons and Intestinal Cells. Mol Cell Biol 2017; 37:MCB.00192-17. [PMID: 28716951 DOI: 10.1128/mcb.00192-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/07/2017] [Indexed: 12/18/2022] Open
Abstract
Ca2+- and diacylglycerol (DAG)-activated protein kinase C (cPKC) promotes learning and behavioral plasticity. However, knowledge of in vivo regulation and exact functions of cPKCs that affect behavior is limited. We show that PKC-2, a Caenorhabditis elegans cPKC, is essential for a complex behavior, thermotaxis. C. elegans memorizes a nutrient-associated cultivation temperature (Tc ) and migrates along the Tc within a 17 to 25°C gradient. pkc-2 gene disruption abrogated thermotaxis; a PKC-2 transgene, driven by endogenous pkc-2 promoters, restored thermotaxis behavior in pkc-2-/- animals. Cell-specific manipulation of PKC-2 activity revealed that thermotaxis is controlled by cooperative PKC-2-mediated signaling in both AFD sensory neurons and intestinal cells. Cold-directed migration (cryophilic drive) precedes Tc tracking during thermotaxis. Analysis of temperature-directed behaviors elicited by persistent PKC-2 activation or inhibition in AFD (or intestine) disclosed that PKC-2 regulates initiation and duration of cryophilic drive. In AFD neurons, PKC-2 is a Ca2+ sensor and signal amplifier that operates downstream from cyclic GMP-gated cation channels and distal guanylate cyclases. UNC-18, which regulates neurotransmitter and neuropeptide release from synaptic vesicles, is a critical PKC-2 effector in AFD. UNC-18 variants, created by mutating Ser311 or Ser322, disrupt thermotaxis and suppress PKC-2-dependent cryophilic migration.
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27
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Shimobayashi E, Kapfhammer JP. Increased biological activity of protein Kinase C gamma is not required in Spinocerebellar ataxia 14. Mol Brain 2017; 10:34. [PMID: 28738819 PMCID: PMC5525338 DOI: 10.1186/s13041-017-0313-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/04/2017] [Indexed: 12/17/2022] Open
Abstract
Spinocerebellar ataxia (SCA) is an autosomal dominant neurodegenerative disorder characterized by slowly progressive cerebellar dysfunction. Currently, 42 SCA types are known, some of which are caused by CAG repeat expansions, but others are caused by point mutations or deletions. Spinocerebellar ataxia type 14 (SCA14) is caused by missense mutations or deletions in the PRKCG gene, coding for protein kinase C gamma (PKCγ). It is still not well understood how these mutations eventually cause Purkinje cell dysfunction and death. Because PKCγ is a well characterized signaling protein highly expressed in Purkinje cells SCA14 offers the chance to better understand the pathogenesis of Purkinje cell dysfunction and death. Altered biological activity of PKCγ would be the simplest explanation for the disease phenotype. There are indeed indications that the enzymatic activity of mutated PKCγ proteins could be changed. Many mutations found in SCA14 families are located in the regulatory C1B and C1A domain, while a few mutations are also found in the C2 and in the catalytic C3 and C4 domains. For many of these mutations an increased enzymatic activity could be demonstrated in cell-based assays, but it remains unclear whether there is indeed an altered biological activity of the mutated PKCγ proteins within living Purkinje cells. In this study we used the dendritic morphology of developing Purkinje cells to detect increased biological activity of PKCγ after expression of different mutated PKCγ proteins. Our results indicate that two out of three known mutations in the catalytic domain of PKCγ did indeed show increased biological activity. On the other hand, none of the five tested mutations located in the regulatory C1 or the C2 domain showed an increased biological activity. Our findings indicate that SCA14 mutations located in different domains of the PRKCG gene cause SCA14 by different mechanisms and that an increased constitutive activity of PKCγ may be one, but cannot be the only mechanism to cause disease in SCA14.
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Affiliation(s)
- Etsuko Shimobayashi
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, 4056, Basel, Switzerland.
| | - Josef P Kapfhammer
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistrasse 20, 4056, Basel, Switzerland
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28
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Newton AC, Brognard J. Reversing the Paradigm: Protein Kinase C as a Tumor Suppressor. Trends Pharmacol Sci 2017; 38:438-447. [PMID: 28283201 PMCID: PMC5403564 DOI: 10.1016/j.tips.2017.02.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 12/20/2022]
Abstract
The discovery in the 1980s that protein kinase C (PKC) is a receptor for the tumor-promoting phorbol esters fueled the dogma that PKC is an oncoprotein. Yet 30+ years of clinical trials for cancer using PKC inhibitors not only failed, but in some instances worsened patient outcome. The recent analysis of cancer-associated mutations, from diverse cancers and throughout the PKC family, revealed that PKC isozymes are generally inactivated in cancer, supporting a tumor suppressive function. In keeping with a bona fide tumor suppressive role, germline causal loss-of-function (LOF) mutations in one isozyme have recently been identified in lymphoproliferative disorders. Thus, strategies in cancer treatment should focus on restoring rather than inhibiting PKC.
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Affiliation(s)
- Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, USA.
| | - John Brognard
- Laboratory of Cell and Developmental Signaling, National Cancer Institute at Frederick, Frederick, MD 21702, USA; Cancer Research UK Manchester Institute, Manchester, UK.
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29
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Callender J, Newton A. Conventional protein kinase C in the brain: 40 years later. Neuronal Signal 2017; 1:NS20160005. [PMID: 32714576 PMCID: PMC7373245 DOI: 10.1042/ns20160005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/02/2017] [Accepted: 03/07/2017] [Indexed: 12/16/2022] Open
Abstract
Protein kinase C (PKC) is a family of enzymes whose members transduce a large variety of cellular signals instigated by the receptor-mediated hydrolysis of membrane phospholipids. While PKC has been widely implicated in the pathology of diseases affecting all areas of physiology including cancer, diabetes, and heart disease-it was discovered, and initially characterized, in the brain. PKC plays a key role in controlling the balance between cell survival and cell death. Its loss of function is generally associated with cancer, whereas its enhanced activity is associated with neurodegeneration. This review presents an overview of signaling by diacylglycerol (DG)-dependent PKC isozymes in the brain, and focuses on the role of the Ca2+-sensitive conventional PKC isozymes in neurodegeneration.
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Affiliation(s)
- Julia A. Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
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30
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van Unen J, Rashidfarrokhi A, Hoogendoorn E, Postma M, Gadella TWJ, Goedhart J. Quantitative Single-Cell Analysis of Signaling Pathways Activated Immediately Downstream of Histamine Receptor Subtypes. Mol Pharmacol 2016; 90:162-76. [PMID: 27358232 DOI: 10.1124/mol.116.104505] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/28/2016] [Indexed: 01/09/2023] Open
Abstract
Genetically encoded biosensors based on Förster resonance energy transfer (FRET) can visualize responses of individual cells in real time. Here, we evaluated whether FRET-based biosensors provide sufficient contrast and specificity to measure activity of G-protein-coupled receptors. The four histamine receptor subtypes (H1R, H2R, H3R, and H4R) respond to the ligand histamine by activating three canonical heterotrimeric G-protein-mediated signaling pathways with a reported high degree of specificity. Using FRET-based biosensors, we demonstrate that H1R activates Gαq. We also observed that H1R activates Gαi, albeit at a 10-fold lower potency. In addition to increasing cAMP levels, most likely via Gαs, we found that the H2R induces Gαq-mediated calcium release. The H3R and H4R activated Gαi with high specificity and a high potency. We demonstrate that a number of FRET sensors provide sufficient contrast to: 1) analyze the specificity of the histamine receptor subtypes for different heterotrimeric G-protein families with single-cell resolution, 2) probe for antagonist specificity, and 3) allow the measurement of single-cell concentration-response curves.
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Affiliation(s)
- Jakobus van Unen
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Ali Rashidfarrokhi
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Eelco Hoogendoorn
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Marten Postma
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Theodorus W J Gadella
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
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Alfonso SI, Callender JA, Hooli B, Antal CE, Mullin K, Sherman MA, Lesné SE, Leitges M, Newton AC, Tanzi RE, Malinow R. Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer's disease. Sci Signal 2016; 9:ra47. [PMID: 27165780 PMCID: PMC5154619 DOI: 10.1126/scisignal.aaf6209] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is a progressive dementia disorder characterized by synaptic degeneration and amyloid-β (Aβ) accumulation in the brain. Through whole-genome sequencing of 1345 individuals from 410 families with late-onset AD (LOAD), we identified three highly penetrant variants in PRKCA, the gene that encodes protein kinase Cα (PKCα), in five of the families. All three variants linked with LOAD displayed increased catalytic activity relative to wild-type PKCα as assessed in live-cell imaging experiments using a genetically encoded PKC activity reporter. Deleting PRKCA in mice or adding PKC antagonists to mouse hippocampal slices infected with a virus expressing the Aβ precursor CT100 revealed that PKCα was required for the reduced synaptic activity caused by Aβ. In PRKCA(-/-) neurons expressing CT100, introduction of PKCα, but not PKCα lacking a PDZ interaction moiety, rescued synaptic depression, suggesting that a scaffolding interaction bringing PKCα to the synapse is required for its mediation of the effects of Aβ. Thus, enhanced PKCα activity may contribute to AD, possibly by mediating the actions of Aβ on synapses. In contrast, reduced PKCα activity is implicated in cancer. Hence, these findings reinforce the importance of maintaining a careful balance in the activity of this enzyme.
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Affiliation(s)
- Stephanie I Alfonso
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julia A Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Basavaraj Hooli
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Corina E Antal
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kristina Mullin
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Mathew A Sherman
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Sylvain E Lesné
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Michael Leitges
- Biotechnology Centre of Oslo, University of Oslo, Oslo 0317, Norway
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| | - Roberto Malinow
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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Novel Features of DAG-Activated PKC Isozymes Reveal a Conserved 3-D Architecture. J Mol Biol 2016; 428:121-141. [DOI: 10.1016/j.jmb.2015.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/01/2015] [Indexed: 01/17/2023]
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Wiemhoefer A, Stargardt A, van der Linden WA, Renner MC, van Kesteren RE, Stap J, Raspe MA, Tomkinson B, Kessels HW, Ovaa H, Overkleeft HS, Florea B, Reits EA. Tripeptidyl Peptidase II Mediates Levels of Nuclear Phosphorylated ERK1 and ERK2. Mol Cell Proteomics 2015; 14:2177-93. [PMID: 26041847 DOI: 10.1074/mcp.m114.043331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Indexed: 12/22/2022] Open
Abstract
Tripeptidyl peptidase II (TPP2) is a serine peptidase involved in various biological processes, including antigen processing, cell growth, DNA repair, and neuropeptide mediated signaling. The underlying mechanisms of how a peptidase can influence this multitude of processes still remain unknown. We identified rapid proteomic changes in neuroblastoma cells following selective TPP2 inhibition using the known reversible inhibitor butabindide, as well as a new, more potent, and irreversible peptide phosphonate inhibitor. Our data show that TPP2 inhibition indirectly but rapidly decreases the levels of active, di-phosphorylated extracellular signal-regulated kinase 1 (ERK1) and ERK2 in the nucleus, thereby down-regulating signal transduction downstream of growth factors and mitogenic stimuli. We conclude that TPP2 mediates many important cellular functions by controlling ERK1 and ERK2 phosphorylation. For instance, we show that TPP2 inhibition of neurons in the hippocampus leads to an excessive strengthening of synapses, indicating that TPP2 activity is crucial for normal brain function.
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Affiliation(s)
- Anne Wiemhoefer
- From the ‡Department of Cell Biology and Histology, Academic Medical Centre- University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Anita Stargardt
- From the ‡Department of Cell Biology and Histology, Academic Medical Centre- University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Wouter A van der Linden
- §Department of Pathology, Stanford School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5324
| | - Maria C Renner
- ¶Netherlands Institute for Neuroscience, Meibergdreef 47, 1105BA Amsterdam, The Netherlands
| | - Ronald E van Kesteren
- ‖Center for Neurogenomics and Cognitive Research, VU University Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands
| | - Jan Stap
- From the ‡Department of Cell Biology and Histology, Academic Medical Centre- University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Marcel A Raspe
- **Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Birgitta Tomkinson
- ‡‡Department of Medical Biochemistry and Microbiology, University of Uppsala, Husargatan 3, 75123 Uppsala, Sweden
| | - Helmut W Kessels
- ¶Netherlands Institute for Neuroscience, Meibergdreef 47, 1105BA Amsterdam, The Netherlands
| | - Huib Ovaa
- **Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Herman S Overkleeft
- §§Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Bogdan Florea
- §§Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Eric A Reits
- From the ‡Department of Cell Biology and Histology, Academic Medical Centre- University of Amsterdam, Meibergdreef 15, 1105AZ Amsterdam, The Netherlands;
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Takahashi H, Adachi N, Shirafuji T, Danno S, Ueyama T, Vendruscolo M, Shuvaev AN, Sugimoto T, Seki T, Hamada D, Irie K, Hirai H, Sakai N, Saito N. Identification and characterization of PKCγ, a kinase associated with SCA14, as an amyloidogenic protein. Hum Mol Genet 2015; 24:525-39. [PMID: 25217572 DOI: 10.1093/hmg/ddu472] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Amyloid assemblies are associated with a wide range of human disorders, including Alzheimer's and Parkinson's diseases. Here, we identify protein kinase C (PKC) γ, a serine/threonine kinase mutated in the neurodegenerative disease spinocerebellar ataxia type 14 (SCA14), as a novel amyloidogenic protein with no previously characterized amyloid-prone domains. We found that overexpression of PKCγ in cultured cells, as well as in vitro incubation of PKCγ without heat or chemical denaturants, causes amyloid-like fibril formation of this protein. We also observed that SCA14-associated mutations in PKCγ accelerate the amyloid-like fibril formation both in cultured cells and in vitro. We show that the C1A and kinase domains of PKCγ are involved in its soluble dimer and aggregate formation and that SCA14-associated mutations in the C1 domain cause its misfolding and aggregation. Furthermore, long-term time-lapse imaging indicates that aggregates of mutant PKCγ are highly toxic to neuronal cells. Based on these findings, we propose that PKCγ could form amyloid-like fibrils in physiological and/or pathophysiological conditions such as SCA14. More generally, our results provide novel insights into the mechanism of amyloid-like fibril formation by multi-domain proteins.
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Affiliation(s)
| | - Naoko Adachi
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | | | - Sally Danno
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Takehiko Ueyama
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Anton N Shuvaev
- Department of Neurophysiology, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Takuya Sugimoto
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Takahiro Seki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Daizo Hamada
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan and
| | - Kazuhiro Irie
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Norio Sakai
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Science, Hiroshima University, Hiroshima 734-8551, Japan
| | - Naoaki Saito
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
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Abstract
Heredoataxias are a group of genetic disorders with a cerebellar syndrome as the leading clinical manifestation. The current classification distinguishes heredoataxias according to the trait of inheritance into autosomal dominant, autosomal recessive, X-linked, and maternally inherited heredoataxias. The autosomal dominant heredoataxias are separated into spinocerebellar ataxias (SCA1-8, 10-15, 17-23, 25-30, and dentato-rubro-pallido-luysian atrophy), episodic ataxias (EA1-7), and autosomal dominant mitochondrial heredoataxias (Leigh syndrome, MIRAS, ADOAD, and AD-CPEO). The autosomal recessive ataxias are separated into Friedreich ataxia, ataxia due to vitamin E deficiency, ataxia due to Abeta-lipoproteinemia, Refsum disease, late-onset Tay-Sachs disease, cerebrotendineous xanthomatosis, spinocerebellar ataxia with axonal neuropathy, ataxia telangiectasia, ataxia telangiectasia-like disorder, ataxia with oculomotor apraxia 1 and 2, spastic ataxia of Charlevoix-Saguenay, Cayman ataxia, Marinesco-Sjögren syndrome, and autosomal recessive mitochondrial ataxias (AR-CPEO, SANDO, SCAE, AHS, IOSCA, MEMSA, LBSL CoQ-deficiency, PDC-deficiency). Only two of the heredoataxias, fragile X/tremor/ataxia syndrome, and XLSA/A are transmitted via an X-linked trait. Maternally inherited heredoataxias are due to point mutations in genes encoding for tRNAs, rRNAs, respiratory chain subunits or single large scale deletions/duplications of the mitochondrial DNA and include MELAS, MERRF, KSS, PS, MILS, NARP, and non-syndromic mitochondrial disorders. Treatment of heredoataxias is symptomatic and supportive and may have a beneficial effect in single patients.**Please see page 424 for abbreviation list.
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Ji J, Hassler ML, Shimobayashi E, Paka N, Streit R, Kapfhammer JP. Increased protein kinase C gamma activity induces Purkinje cell pathology in a mouse model of spinocerebellar ataxia 14. Neurobiol Dis 2014; 70:1-11. [PMID: 24937631 DOI: 10.1016/j.nbd.2014.06.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 06/02/2014] [Accepted: 06/07/2014] [Indexed: 12/27/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are hereditary diseases leading to Purkinje cell degeneration and cerebellar dysfunction. Most forms of SCA are caused by expansion of CAG repeats similar to other polyglutamine disorders such as Huntington's disease. In contrast, in the autosomal dominant SCA-14 the disease is caused by mutations in the protein kinase C gamma (PKCγ) gene which is a well characterized signaling molecule in cerebellar Purkinje cells. The study of SCA-14, therefore, offers the unique opportunity to reveal the molecular and pathological mechanism eventually leading to Purkinje cell dysfunction and degeneration. We have created a mouse model of SCA-14 in which PKCγ protein with a mutation found in SCA-14 is specifically expressed in cerebellar Purkinje cells. We find that in mice expressing the mutated PKCγ protein the morphology of Purkinje cells in cerebellar slice cultures is drastically altered and mimics closely the morphology seen after pharmacological PKC activation. Similar morphological abnormalities were seen in localized areas of the cerebellum of juvenile transgenic mice in vivo. In adult transgenic mice there is evidence for some localized loss of Purkinje cells but there is no overall cerebellar atrophy. Transgenic mice show a mild cerebellar ataxia revealed by testing on the rotarod and on the walking beam. Our findings provide evidence for both an increased PKCγ activity in Purkinje cells in vivo and for pathological changes typical for cerebellar disease thus linking the increased and dysregulated activity of PKCγ tightly to the development of cerebellar disease in SCA-14 and possibly also in other forms of SCA.
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Affiliation(s)
- Jingmin Ji
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland
| | - Melanie L Hassler
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland
| | - Etsuko Shimobayashi
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland
| | - Nagendher Paka
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland
| | - Raphael Streit
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland
| | - Josef P Kapfhammer
- Anatomical Institute, Department of Biomedicine Basel, University of Basel, Pestalozzistr, 20, CH-4056 Basel, Switzerland.
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Yamamoto K, Seki T, Yamamoto H, Adachi N, Tanaka S, Hide I, Saito N, Sakai N. Deregulation of the actin cytoskeleton and macropinocytosis in response to phorbol ester by the mutant protein kinase C gamma that causes spinocerebellar ataxia type 14. Front Physiol 2014; 5:126. [PMID: 24744737 PMCID: PMC3978357 DOI: 10.3389/fphys.2014.00126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/13/2014] [Indexed: 11/14/2022] Open
Abstract
Several missense mutations in the protein kinase Cγ (γPKC) gene have been found to cause spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. γPKC is a neuron-specific member of the classical PKCs and is activated and translocated to subcellular regions as a result of various stimuli, including diacylglycerol synthesis, increased intracellular Ca2+ and phorbol esters. We investigated whether SCA14 mutations affect the γPKC-related functions by stimulating HeLa cells with TPA (12-O-tetradecanoylpholbol 13-acetate), a type of phorbol ester. Wild-type (WT) γPKC-GFP was translocated to the plasma membrane within 10 min of TPA stimulation, followed by its perinuclear translocation and cell shrinkage, in a PKC kinase activity- and microtubule-dependent manner. On the other hand, although SCA14 mutant γPKC-GFP exhibited a similar translocation to the plasma membrane, the subsequent perinuclear translocation and cell shrinkage were significantly impaired in response to TPA. Translocated WT γPKC colocalized with F-actin and formed large vesicular structures in the perinuclear region. The uptake of FITC-dextran, a marker of macropinocytosis, was promoted by TPA stimulation in cells expressing WT γPKC, and FITC-dextran was surrounded by γPKC-positive vesicles. Moreover, TPA induced the phosphorylation of MARCKS, which is a membrane-substrate of PKC, resulting in the translocation of phosphorylated MARCKS to the perinuclear region, suggesting that TPA induces macropinocytosis via γPKC activation. However, TPA failed to activate macropinocytosis and trigger the translocation of phosphorylated MARCKS in cells expressing the SCA14 mutant γPKC. These findings suggest that γPKC is involved in the regulation of the actin cytoskeleton and macropinocytosis in HeLa cells, while SCA14 mutant γPKC fails to regulate these processes due to its reduced kinase activity at the plasma membrane. This property might be involved in pathogenesis of SCA14.
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Affiliation(s)
- Kazuhiro Yamamoto
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan ; Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University Kumamoto, Japan
| | - Hikaru Yamamoto
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan ; Biosignal Research Center, Kobe University Kobe, Japan
| | - Naoko Adachi
- Biosignal Research Center, Kobe University Kobe, Japan
| | - Shigeru Tanaka
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Izumi Hide
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
| | - Naoaki Saito
- Biosignal Research Center, Kobe University Kobe, Japan
| | - Norio Sakai
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University Hiroshima, Japan
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Goedhart J, van Unen J, Adjobo-Hermans MJW, Gadella TWJ. Signaling efficiency of Gαq through its effectors p63RhoGEF and GEFT depends on their subcellular location. Sci Rep 2014; 3:2284. [PMID: 23884432 PMCID: PMC3722567 DOI: 10.1038/srep02284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/10/2013] [Indexed: 02/02/2023] Open
Abstract
The p63RhoGEF and GEFT proteins are encoded by the same gene and both members of the Dbl family of guanine nucleotide exchange factors. These proteins can be activated by the heterotrimeric G-protein subunit Gαq. We show that p63RhoGEF is located at the plasma membrane, whereas GEFT is confined to the cytoplasm. Live-cell imaging studies yielded quantitative information on diffusion coefficients, association rates and encounter times of GEFT and p63RhoGEF. Calcium signaling was examined as a measure of the signal transmission, revealing more efficient signaling through the membrane-associated p63RhoGEF. A rapamycin dependent recruitment system was used to dynamically alter the subcellular location and concentration of GEFT, showing efficient signaling through GEFT only upon membrane recruitment. Together, our results show efficient signal transmission through membrane located effectors, and highlight a role for increased concentration rather than increased encounter times due to membrane localization in the Gαq mediated pathways to p63RhoGEF and PLCβ.
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Affiliation(s)
- Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, P.O. Box 94215, NL-1090 GE Amsterdam, The Netherlands.
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Jezierska J, Goedhart J, Kampinga HH, Reits EA, Verbeek DS. SCA14 mutation V138E leads to partly unfolded PKCγ associated with an exposed C-terminus, altered kinetics, phosphorylation and enhanced insolubilization. J Neurochem 2013; 128:741-51. [DOI: 10.1111/jnc.12491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/03/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Justyna Jezierska
- Department of Genetics; University of Groningen; University Medical Center Groningen; Groningen The Netherlands
| | - Joachim Goedhart
- Section Molecular Cytology; van Leeuwenhoek Centre for Advanced Microscopy; Swammerdam Institute for Life Sciences; University of Amsterdam; Amsterdam The Netherlands
| | - Harm H. Kampinga
- Department of Cell Biology; University Medical Center Groningen; University of Groningen; Groningen The Netherlands
| | - Eric A. Reits
- Department of Cell Biology and Histology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - Dineke S. Verbeek
- Department of Genetics; University of Groningen; University Medical Center Groningen; Groningen The Netherlands
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Seidel K, Siswanto S, Brunt ERP, den Dunnen W, Korf HW, Rüb U. Brain pathology of spinocerebellar ataxias. Acta Neuropathol 2012; 124:1-21. [PMID: 22684686 DOI: 10.1007/s00401-012-1000-x] [Citation(s) in RCA: 283] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/25/2012] [Accepted: 05/25/2012] [Indexed: 12/22/2022]
Abstract
The autosomal dominant cerebellar ataxias (ADCAs) represent a heterogeneous group of neurodegenerative diseases with progressive ataxia and cerebellar degeneration. The current classification of this disease group is based on the underlying genetic defects and their typical disease courses. According to this categorization, ADCAs are divided into the spinocerebellar ataxias (SCAs) with a progressive disease course, and the episodic ataxias (EA) with episodic occurrences of ataxia. The prominent disease symptoms of the currently known and genetically defined 31 SCA types result from damage to the cerebellum and interconnected brain grays and are often accompanied by more specific extra-cerebellar symptoms. In the present review, we report the genetic and clinical background of the known SCAs and present the state of neuropathological investigations of brain tissue from SCA patients in the final disease stages. Recent findings show that the brain is commonly seriously affected in the polyglutamine SCAs (i.e. SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17) and that the patterns of brain damage in these diseases overlap considerably in patients suffering from advanced disease stages. In the more rarely occurring non-polyglutamine SCAs, post-mortem neuropathological data currently are scanty and investigations have been primarily performed in vivo by means of MRI brain imaging. Only a minority of SCAs exhibit symptoms and degenerative patterns allowing for a clear and unambiguous diagnosis of the disease, e.g. retinal degeneration in SCA7, tau aggregation in SCA11, dentate calcification in SCA20, protein depositions in the Purkinje cell layer in SCA31, azoospermia in SCA32, and neurocutaneous phenotype in SCA34. The disease proteins of polyglutamine ataxias and some non-polyglutamine ataxias aggregate as cytoplasmic or intranuclear inclusions and serve as morphological markers. Although inclusions may impair axonal transport, bind transcription factors, and block protein quality control, detailed molecular and pathogenetic consequences remain to be determined.
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Affiliation(s)
- Kay Seidel
- Dr. Senckenbergisches Chronomedizinisches Institut, Goethe University, Theodor-Stern-Kai 7, 60950, Frankfurt/Main, Germany
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Establishment of a novel fluorescence-based method to evaluate chaperone-mediated autophagy in a single neuron. PLoS One 2012; 7:e31232. [PMID: 22363588 PMCID: PMC3280339 DOI: 10.1371/journal.pone.0031232] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 01/04/2012] [Indexed: 11/19/2022] Open
Abstract
Background Chaperone-mediated autophagy (CMA) is a selective autophagy-lysosome protein degradation pathway. The role of CMA in normal neuronal functions and in neural disease pathogenesis remains unclear, in part because there is no available method to monitor CMA activity at the single-cell level. Methodology/Principal Findings We sought to establish a single-cell monitoring method by visualizing translocation of CMA substrates from the cytosol to lysosomes using the HaloTag (HT) system. GAPDH, a CMA substrate, was fused to HT (GAPDH-HT); this protein accumulated in the lysosomes of HeLa cells and cultured cerebellar Purkinje cells (PCs) after labeling with fluorescent dye-conjugated HT ligand. Lysosomal accumulation was enhanced by treatments that activate CMA and prevented by siRNA-mediated knockdown of LAMP2A, a lysosomal receptor for CMA, and by treatments that inactivate CMA. These results suggest that lysosomal accumulation of GAPDH-HT reflects CMA activity. Using this method, we revealed that mutant γPKC, which causes spinocerebellar ataxia type 14, decreased CMA activity in cultured PCs. Conclusion/Significance In the present study, we established a novel fluorescent-based method to evaluate CMA activity in a single neuron. This novel method should be useful and valuable for evaluating the role of CMA in various neuronal functions and neural disease pathogenesis.
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Affiliation(s)
- S H Subramony
- McKnight Brain Institute at UF, Gainesville, FL 32610, USA.
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Mutant PKCγ in spinocerebellar ataxia type 14 disrupts synapse elimination and long-term depression in Purkinje cells in vivo. J Neurosci 2011; 31:14324-34. [PMID: 21976518 DOI: 10.1523/jneurosci.5530-10.2011] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cerebellar Purkinje cells (PCs) express a large amount of the γ isoform of protein kinase C (PKCγ) and a modest level of PKCα. The PKCγ is involved in the pruning of climbing fiber (CF) synapses from developing PCs, and PKCα plays a critical role in long-term depression (LTD) at parallel fiber (PF)-PC synapses. Moreover, the PKC signaling in PCs negatively modulates the nonselective transient receptor potential cation channel type 3 (TRPC3), the opening of which elicits slow EPSCs at PF-PC synapses. Autosomal dominant spinocerebellar ataxia type 14 (SCA14) is caused by mutations in PKCγ. To clarify the pathology of this disorder, mutant (S119P) PKCγ tagged with GFP was lentivirally expressed in developing and mature mouse PCs in vivo, and the effects were assessed 3 weeks after the injection. Mutant PKCγ-GFP aggregated in PCs without signs of degeneration. Electrophysiology results showed impaired pruning of CF synapses from developing PCs, failure of LTD expression, and increases in slow EPSC amplitude. We also found that mutant PKCγ colocalized with wild-type PKCγ, which suggests that mutant PKCγ acts in a dominant-negative manner on wild-type PKCγ. In contrast, PKCα did not colocalize with mutant PKCγ. The membrane residence time of PKCα after depolarization-induced translocation, however, was significantly decreased when it was present with the mutant PKCγ construct. These results suggest that mutant PKCγ in PCs of SCA14 patients could differentially impair the membrane translocation kinetics of wild-type γ and α PKCs, which would disrupt synapse pruning, synaptic plasticity, and synaptic transmission.
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Quantitative co-expression of proteins at the single cell level--application to a multimeric FRET sensor. PLoS One 2011; 6:e27321. [PMID: 22114669 PMCID: PMC3219669 DOI: 10.1371/journal.pone.0027321] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 10/13/2011] [Indexed: 01/05/2023] Open
Abstract
Background Co-expression of proteins is generally achieved by introducing two (or more) independent plasmids into cells, each driving the expression of a different protein of interest. However, the relative expression levels may vary strongly between individual cells and cannot be controlled. Ideally, co-expression occurs at a defined ratio, which is constant among cells. This feature is of particular importance for quantitative single cell studies, especially those employing bimolecular Förster Resonance Energy Transfer (FRET) sensors. Methodology/Principal Findings Four co-expression strategies based on co-transfection, a dual promotor plasmid, an internal ribosome entry site (IRES) and a viral 2A peptide were selected. Co-expression of two spectrally separable fluorescent proteins in single living cells was quantified. It is demonstrated that the 2A peptide strategy can be used for robust equimolar co-expression, while the IRES sequence allows expression of two proteins at a ratio of approximately 3:1. Combined 2A and IRES elements were used for the construction of a single plasmid that drives expression of three individual proteins, which generates a FRET sensor for measuring heterotrimeric G-protein activation. The plasmid drives co-expression of donor and acceptor tagged subunits, with reduced heterogeneity, and can be used to measure G-protein activation in single living cells. Conclusions/Significance Quantitative co-expression of two or more proteins can be achieved with little cell-to-cell variability. This finding enables reliable co-expression of donor and acceptor tagged proteins for FRET studies, which is of particular importance for the development of novel bimolecular sensors that can be expressed from single plasmid.
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Shaping up the membrane: diacylglycerol coordinates spatial orientation of signaling. Trends Biochem Sci 2011; 36:593-603. [PMID: 21798744 DOI: 10.1016/j.tibs.2011.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 06/21/2011] [Accepted: 06/23/2011] [Indexed: 11/23/2022]
Abstract
Diacylglycerol signals by binding and activating C1 domain-containing proteins expressed principally in neuronal and immune tissues. This restricted expression profile suggests that diacylglycerol-regulated signals are particularly relevant in cell-cell communication processes in which active endocytosis and exocytosis take place. Not surprisingly, various experimental approaches have demonstrated a crucial role for diacylglycerol effectors and metabolizing enzymes in the control of immune responses, neuron communication and phagocytosis. Current research delineates a scenario in which coordinated decoding of diacylglycerol signals is translated into complex biological responses such as neuronal plasticity, T cell development or cytolytic killing. Diacylglycerol functions reach maximal diversity in these highly specialized systems in which signal intensity directly regulates distinct biological outcomes. This review brings together the most recent studies, emphasizing the contribution of compartmentalized DAG metabolism to orientated signaling events.
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Seki T, Adachi N, Abe-Seki N, Shimahara T, Takahashi H, Yamamoto K, Saito N, Sakai N. Elucidation of the molecular mechanism and exploration of novel therapeutics for spinocerebellar ataxia caused by mutant protein kinase Cγ. J Pharmacol Sci 2011; 116:239-47. [PMID: 21666345 DOI: 10.1254/jphs.11r04cp] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Spinocerebellar ataxia (SCA) is an inherited neurodegenerative disorder that is characterized by cerebellar atrophy and progressive ataxia and is classified into 31 types by the genetic locus. Recently, missense mutations of PRKCG genes that code protein kinase Cγ (γPKC) have been identified as a causal gene of SCA14. To explore the molecular mechanism of SCA14 pathogenesis, we investigated how mutant γPKC causes the neurodegeneration of cerebellar Purkinje cells (PCs) by expressing mutant γPKC-GFP in cell lines and primary cultured PCs. Mutant γPKC was susceptible to aggregation in the cytoplasm, which led to an impairment of the ubiquitin-proteasome system and apoptosis. Furthermore, mutant γPKC induced improper dendritic development of cultured PCs in an aggregation-independent manner. Stimulation-induced translocation of mutant γPKC in PC dendrites was prominently attenuated by the reduced mobility of oligomerized mutant γPKC, which resulted in attenuated signal transduction and the improper morphology of PC dendrites. These findings suggested that the oligomerization and aggregation of mutant γPKC caused improper dendritic development and apoptosis of PCs, which led to cerebellar dysfunction and SCA14 pathogenesis. We screened the chemicals that improved these cellular dysfunctions and identified several compounds, including trehalose and Congo red, which could be novel therapeutics for SCA14.
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Affiliation(s)
- Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
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Marelli C, Cazeneuve C, Brice A, Stevanin G, Dürr A. Autosomal dominant cerebellar ataxias. Rev Neurol (Paris) 2011; 167:385-400. [PMID: 21546047 DOI: 10.1016/j.neurol.2011.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/27/2011] [Indexed: 12/30/2022]
Abstract
Cerebellar ataxias with autosomal dominant transmission (ADCA) are far rarer than sporadic cases of cerebellar ataxia. The identification of genes involved in dominant forms has confirmed the genetic heterogeneity of these conditions and of the underlying mechanisms and pathways. To date, at least 28 genetic loci and, among them, 20 genes have been identified. In many instances, the phenotype is not restricted to cerebellar dysfunction but includes more complex multisystemic neurological deficits. Seven ADCA (SCA1, 2, 3, 6, 7, 17, and dentatorubro-pallido-luysian atrophy) are caused by repeat expansions in the corresponding proteins; phenotype-genotype correlations have shown that repeat size influences the progression of the disease, its severity and clinical differences among patients, including the phenomenon of anticipation between generations. All other ADCA are caused either by non-coding repeat expansions, conventional mutations or large rearrangements in genes with different functions. This review will focus on the genetic features of ADCA and on the clinical differences among the different forms.
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Affiliation(s)
- C Marelli
- Département de génétique et cytogénétique, consultation de génétique clinique, CHU Pitié-Salpêtrière, AP-HP, 47, boulevard de l'Hôpital, 75013 Paris, France
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ERK/p90(RSK)/14-3-3 signalling has an impact on expression of PEA3 Ets transcription factors via the transcriptional repressor capicúa. Biochem J 2011; 433:515-25. [PMID: 21087211 PMCID: PMC3025492 DOI: 10.1042/bj20101562] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Compounds that inhibit signalling upstream of ERK (extracellular-signal-regulated kinase) are promising anticancer therapies, motivating research to define how this pathway promotes cancers. In the present study, we show that human capicúa represses mRNA expression for PEA3 (polyoma enhancer activator 3) Ets transcription factors ETV1, ETV4 and ETV5 (ETV is Ets translocation variant), and this repression is relieved by multisite controls of capicúa by ERK, p90RSK (p90 ribosomal S6 kinase) and 14-3-3 proteins. Specifically, 14-3-3 binds to p90RSK-phosphorylated Ser173 of capicúa thereby modulating DNA binding to its HMG (high-mobility group) box, whereas ERK phosphorylations prevent binding of a C-terminal NLS (nuclear localization sequence) to importin α4 (KPNA3). ETV1, ETV4 and ETV5 mRNA levels in melanoma cells are elevated by siRNA (small interfering RNA) knockdown of capicúa, and decreased by inhibiting ERK and/or expressing a form of capicúa that cannot bind to 14-3-3 proteins. Capicúa knockdown also enhances cell migration. The findings of the present study give further mechanistic insights into why ETV1 is highly expressed in certain cancers, indicate that loss of capicúa can desensitize cells to the effects of ERK pathway inhibitors, and highlight interconnections among growth factor signalling, spinocerebellar ataxias and cancers.
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Seki T, Takahashi H, Yamamoto K, Ogawa K, Onji T, Adachi N, Tanaka S, Hide I, Saito N, Sakai N. Congo red, an amyloid-inhibiting compound, alleviates various types of cellular dysfunction triggered by mutant protein kinase cγ that causes spinocerebellar ataxia type 14 (SCA14) by inhibiting oligomerization and aggregation. J Pharmacol Sci 2011; 114:206-16. [PMID: 20938103 DOI: 10.1254/jphs.10170fp] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Several missense mutations in the protein kinase Cγ (γPKC) gene have been found to cause spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. We previously demonstrated that the mutant γPKC found in SCA14 is susceptible to aggregation that induces apoptotic cell death. Congo red is widely used as a histological dye for amyloid detection. Recent evidence has revealed that Congo red has the property to inhibit amyloid oligomers and fibril formation of misfolded proteins. In the present study, we examine whether Congo red inhibits aggregate formation and cytotoxicity of mutant γPKC. Congo red likely inhibits aggregate formation of mutant γPKC – green fluorescent protein (GFP) without affecting its expression level in SH-SY5Y cells. Congo red counteracts the insolubilization of recombinant mutant γPKC, suggesting that the dye inhibits aggregation of mutant γPKC by a direct mechanism. Congo red also inhibits aggregation and oligomerization of mutant γPKC-GFP in primary cultured cerebellar Purkinje cells. Moreover, the dye reverses the improper development of dendrites and inhibits apoptotic cell death in Purkinje cells that express mutant γPKC-GFP. These results indicate that amyloid-inhibiting compounds like Congo red may be novel therapeutics for SCA14.
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Affiliation(s)
- Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551, Japan
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Carter H, Samayoa J, Hruban RH, Karchin R. Prioritization of driver mutations in pancreatic cancer using cancer-specific high-throughput annotation of somatic mutations (CHASM). Cancer Biol Ther 2010; 10:582-7. [PMID: 20581473 DOI: 10.4161/cbt.10.6.12537] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Over 20,000 genes were recently sequenced in a series of 24 pancreatic cancers. We applied CHASM (Cancer-specific High-throughput Annotation of Somatic Mutations) to 963 of the missense somatic missense mutations discovered in these 24 cancers. CHASM identified putative driver mutations (false discovery rate ≤0.3) in three known pancreatic cancer driver genes (P53, SMAD4, CDKN2A). An additional 15 genes with putative driver mutations include genes coding for kinases (PIK3CG, DGKA, STK33, TTK and PRKCG), for cell cycle related proteins (NEK8), and for proteins involved in cell adhesion (CMAS, PCDHB2). These and other mutations identified by CHASM point to potential "driver genes" in pancreatic cancer that should be prioritized for additional follow-up.
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Affiliation(s)
- Hannah Carter
- Department of Biomedical Engineering and Institute for Computational Medicine, The Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Kimmel Cancer Center, Baltimore, MD, USA
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