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Uzay B, Houcek A, Ma ZZ, Konradi C, Monteggia LM, Kavalali ET. Neurotransmitter release progressively desynchronizes in induced human neurons during synapse maturation and aging. Cell Rep 2023; 42:112042. [PMID: 36701235 PMCID: PMC10366341 DOI: 10.1016/j.celrep.2023.112042] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 11/04/2022] [Accepted: 01/13/2023] [Indexed: 01/26/2023] Open
Abstract
Rapid release of neurotransmitters in synchrony with action potentials is considered a key hardwired property of synapses. Here, in glutamatergic synapses formed between induced human neurons, we show that action potential-dependent neurotransmitter release becomes progressively desynchronized as synapses mature and age. In this solely excitatory network, the emergence of NMDAR-mediated transmission elicits endoplasmic reticulum (ER) stress leading to downregulation of key presynaptic molecules, synaptotagmin-1 and cysteine string protein α, that synchronize neurotransmitter release. The emergence of asynchronous release with neuronal maturity and subsequent aging is maintained by the high-affinity Ca2+ sensor synaptotagmin-7 and suppressed by the introduction of GABAergic transmission into the network, inhibition of NMDARs, and ER stress. These results suggest that long-term disruption of excitation-inhibition balance affects the synchrony of excitatory neurotransmission in human synapses.
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Affiliation(s)
- Burak Uzay
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA
| | - Aiden Houcek
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA
| | - Z Zack Ma
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA
| | - Christine Konradi
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA
| | - Lisa M Monteggia
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA
| | - Ege T Kavalali
- Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Pharmacology, Vanderbilt University, 7130A MRB III 465 21st Avenue South, Nashville, TN 37240-7933, USA.
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2
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Flores-Montero K, Berberián MV, Mayorga LS, Tomes CN, Ruete MC. The molecular chaperone cysteine string protein is required for monomeric SNARE proteins to assemble in trans-complexes during human sperm acrosomal exocytosis†. Biol Reprod 2023; 108:229-240. [PMID: 36308432 DOI: 10.1093/biolre/ioac196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/06/2022] [Accepted: 10/24/2022] [Indexed: 11/13/2022] Open
Abstract
Membrane fusion in sperm cells is crucial for acrosomal exocytosis and must be preserved to ensure fertilizing capacity. Evolutionarily conserved protein machinery regulates acrosomal exocytosis. Molecular chaperones play a vital role in spermatogenesis and post-testicular maturation. Cysteine string protein (CSP) is a member of the Hsp40 co-chaperones, and the participation of molecular chaperones in acrosomal exocytosis is poorly understood. In particular, the role of CSP in acrosomal exocytosis has not been reported so far. Using western blot and indirect immunofluorescence, we show that CSP is present in human sperm, is palmitoylated, and predominantly bound to membranes. Moreover, using functional assays and transmission electron microscopy, we report that blocking the function of CSP avoided the assembly of trans-complexes and inhibited exocytosis. In summary, here, we describe the presence of CSP in human sperm and show that this protein has an essential role in membrane fusion during acrosomal exocytosis mediating the trans-SNARE complex assembly between the outer acrosomal and plasma membranes. In general, understanding CSP's role is critical in identifying new biomarkers and generating new rational-based approaches to treat male infertility.
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Affiliation(s)
- Karina Flores-Montero
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Victoria Berberián
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Ciencias Básicas - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Luis Segundo Mayorga
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia Nora Tomes
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Celeste Ruete
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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3
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Lee J, Xu Y, Saidi L, Xu M, Zinsmaier K, Ye Y. Abnormal triaging of misfolded proteins by adult neuronal ceroid lipofuscinosis-associated DNAJC5/CSPα mutants causes lipofuscin accumulation. Autophagy 2023; 19:204-223. [PMID: 35506243 PMCID: PMC9809949 DOI: 10.1080/15548627.2022.2065618] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mutations in DNAJC5/CSPα are associated with adult neuronal ceroid lipofuscinosis (ANCL), a dominant-inherited neurodegenerative disease featuring lysosome-derived autofluorescent storage materials (AFSMs) termed lipofuscin. Functionally, DNAJC5 has been implicated in chaperoning synaptic proteins and in misfolding-associated protein secretion (MAPS), but how DNAJC5 dysfunction causes lipofuscinosis and neurodegeneration is unclear. Here we report two functionally distinct but coupled chaperoning activities of DNAJC5, which jointly regulate lysosomal homeostasis: While endolysosome-associated DNAJC5 promotes ESCRT-dependent microautophagy, a fraction of perinuclear and non-lysosomal DNAJC5 mediates MAPS. Functional proteomics identifies a previously unknown DNAJC5 interactor SLC3A2/CD98hc that is essential for the perinuclear DNAJC5 localization and MAPS but dispensable for microautophagy. Importantly, uncoupling these two processes, as seen in cells lacking SLC3A2 or expressing ANCL-associated DNAJC5 mutants, generates DNAJC5-containing AFSMs resembling NCL patient-derived lipofuscin and induces neurodegeneration in a Drosophila ANCL model. These findings suggest that MAPS safeguards microautophagy to avoid DNAJC5-associated lipofuscinosis and neurodegeneration.Abbreviations: 3-MA: 3-methyladenine; ACTB: actin beta; AFSM: autofluorescent storage materials; ANCL: adult neuronal ceroid lipofuscinosis; Baf. A1: bafilomycin A1; CLN: ceroid lipofuscinosis neuronal; CLU: clusterin; CS: cysteine string domain of DNAJC5/CSPα; CUPS: compartment for unconventional protein secretion; DN: dominant negative; DNAJC5/CSPα: DnaJ heat shock protein family (Hsp40) member C5; eMI: endosomal microautophagy; ESCRT: endosomal sorting complex required for transport; GFP: green fluorescent protein; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; INCL: infant neuronal ceroid lipofuscinosis; JNCL: juvenile neuronal ceroid lipofuscinosis; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LAPTM4B: lysosomal protein transmembrane 4 beta; LN: linker domain of DNAJC5/CSPα; MAPS: misfolding-associated protein secretion; mCh/Ch: mCherry; mCi/Ci: mCitrine; MTOR: mechanistic target of rapamycin kinase; NCL: neuronal ceroid lipofuscinosis; PPT1: palmitoyl-protein thioesterase 1; PQC: protein quality control; SBP: streptavidin binding protein; SGT: small glutamine-rich tetratricopeptide repeat; shRNA: short hairpin RNA; SLC3A2/CD98hc: solute carrier family 3 member 2; SNCA/α-synuclein: synuclein alpha; TMED10: transmembrane p24 trafficking protein 10; UV: ultraviolet; VPS4: vacuolar protein sorting 4 homolog; WT: wild type.
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Affiliation(s)
- Juhyung Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Yue Xu
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Layla Saidi
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Miao Xu
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - Konrad Zinsmaier
- Departments of Neuroscience and Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA,CONTACT Yihong Ye Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD20892, USA
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4
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Huang L, Zhang Z. CSPα in neurodegenerative diseases. Front Aging Neurosci 2022; 14:1043384. [DOI: 10.3389/fnagi.2022.1043384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 10/17/2022] [Indexed: 11/19/2022] Open
Abstract
Adult-onset neuronal ceroid lipofuscinosis (ANCL) is a rare neurodegenerative disease characterized by epilepsy, cognitive degeneration, and motor disorders caused by mutations in the DNAJC5 gene. In addition to being associated with ANCL disease, the cysteine string proteins α (CSPα) encoded by the DNAJC5 gene have been implicated in several neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease. However, the pathogenic mechanism responsible for these neurodegenerative diseases has not yet been elucidated. Therefore, this study examines the functional properties of the CSPα protein and the related mechanisms of neurodegenerative diseases.
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Storey CL, Williams RSB, Fisher PR, Annesley SJ. Dictyostelium discoideum: A Model System for Neurological Disorders. Cells 2022; 11:cells11030463. [PMID: 35159273 PMCID: PMC8833889 DOI: 10.3390/cells11030463] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/14/2022] Open
Abstract
Background: The incidence of neurological disorders is increasing due to population growth and extended life expectancy. Despite advances in the understanding of these disorders, curative strategies for treatment have not yet eventuated. In part, this is due to the complexities of the disorders and a lack of identification of their specific underlying pathologies. Dictyostelium discoideum has provided a useful, simple model to aid in unraveling the complex pathological characteristics of neurological disorders including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, neuronal ceroid lipofuscinoses and lissencephaly. In addition, D. discoideum has proven to be an innovative model for pharmaceutical research in the neurological field. Scope of review: This review describes the contributions of D. discoideum in the field of neurological research. The continued exploration of proteins implicated in neurological disorders in D. discoideum may elucidate their pathological roles and fast-track curative therapeutics.
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Affiliation(s)
- Claire Louise Storey
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Bundoora 3086, Australia; (C.L.S.); (P.R.F.)
| | - Robin Simon Brooke Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham TW20 0EX, UK;
| | - Paul Robert Fisher
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Bundoora 3086, Australia; (C.L.S.); (P.R.F.)
| | - Sarah Jane Annesley
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Bundoora 3086, Australia; (C.L.S.); (P.R.F.)
- Correspondence: ; Tel.: +61-394-791-412
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The bacterial toxin ExoU requires a host trafficking chaperone for transportation and to induce necrosis. Nat Commun 2021; 12:4024. [PMID: 34188051 PMCID: PMC8241856 DOI: 10.1038/s41467-021-24337-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 06/11/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa can cause nosocomial infections, especially in ventilated or cystic fibrosis patients. Highly pathogenic isolates express the phospholipase ExoU, an effector of the type III secretion system that acts on plasma membrane lipids, causing membrane rupture and host cell necrosis. Here, we use a genome-wide screen to discover that ExoU requires DNAJC5, a host chaperone, for its necrotic activity. DNAJC5 is known to participate in an unconventional secretory pathway for misfolded proteins involving anterograde vesicular trafficking. We show that DNAJC5-deficient human cells, or Drosophila flies knocked-down for the DNAJC5 orthologue, are largely resistant to ExoU-dependent virulence. ExoU colocalizes with DNAJC5-positive vesicles in the host cytoplasm. DNAJC5 mutations preventing vesicle trafficking (previously identified in adult neuronal ceroid lipofuscinosis, a human congenital disease) inhibit ExoU-dependent cell lysis. Our results suggest that, once injected into the host cytoplasm, ExoU docks to DNAJC5-positive secretory vesicles to reach the plasma membrane, where it can exert its phospholipase activity Phospholipase ExoU from Pseudomonas aeruginosa acts on plasma membrane lipids in infected cells, causing membrane rupture and host cell necrosis. Here, Deruelle et al. show that once injected into the host cytoplasm, ExoU requires a host chaperone found on secretory vesicles to reach the plasma membrane and exerts its phospholipase activity.
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7
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Wang H, Luo J, Tian X, Xu L, Zhai Z, Cheng M, Chen L, Luo S. DNAJC5 promotes hepatocellular carcinoma cells proliferation though regulating SKP2 mediated p27 degradation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118994. [PMID: 33662413 DOI: 10.1016/j.bbamcr.2021.118994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/06/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022]
Abstract
DNAJC5 (DnaJ heat shock protein family (Hsp40) member C5), also known as cysteine tandem protein (CSPα), is important for maintaining the normal function of nerve tissues, but its oncogenic function remains unknown. Here, we report a unique mechanism underlying the oncogenic function of DNAJC5. DNAJC5 protein expression is highly detectable in human hepatocellular carcinoma (HCC) tissues and is strongly related to a poor prognosis among HCC patients. DNAJC5 overexpression promotes HCC cell proliferation and reduced the ratio of cells in G1 phase of the cell cycle. Furthermore, DNAJC5 interacts with SKP2 and enhances the degradation of p27 (a cyclin-dependent kinase inhibitor1B) by promoting formation of the SKP2-p27 complex. In contrast, DNAJC5 knockdown rescues the SKP2-mediated decrease in p27 protein levels. These results reveal that the DNAJC5-SKP2-p27 pathway is a novel mechanism for the oncogenic function of DNAJC5 in HCC.
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Affiliation(s)
- Hailong Wang
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Jiayu Luo
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Xuesi Tian
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Linlin Xu
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Zhenyu Zhai
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Minzhang Cheng
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Limin Chen
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China
| | - Shiwen Luo
- Center for Experimental Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi, China.
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Butz ES, Chandrachud U, Mole SE, Cotman SL. Moving towards a new era of genomics in the neuronal ceroid lipofuscinoses. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165571. [DOI: 10.1016/j.bbadis.2019.165571] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
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9
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Gundersen CB. Cysteine string proteins. Prog Neurobiol 2020; 188:101758. [DOI: 10.1016/j.pneurobio.2020.101758] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 12/17/2022]
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10
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Mukherjee AB, Appu AP, Sadhukhan T, Casey S, Mondal A, Zhang Z, Bagh MB. Emerging new roles of the lysosome and neuronal ceroid lipofuscinoses. Mol Neurodegener 2019; 14:4. [PMID: 30651094 PMCID: PMC6335712 DOI: 10.1186/s13024-018-0300-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/04/2018] [Indexed: 12/04/2022] Open
Abstract
Neuronal Ceroid Lipofuscinoses (NCLs), commonly known as Batten disease, constitute a group of the most prevalent neurodegenerative lysosomal storage disorders (LSDs). Mutations in at least 13 different genes (called CLNs) cause various forms of NCLs. Clinically, the NCLs manifest early impairment of vision, progressive decline in cognitive and motor functions, seizures and a shortened lifespan. At the cellular level, all NCLs show intracellular accumulation of autofluorescent material (called ceroid) and progressive neuron loss. Despite intense studies the normal physiological functions of each of the CLN genes remain poorly understood. Consequently, the development of mechanism-based therapeutic strategies remains challenging. Endolysosomal dysfunction contributes to pathogenesis of virtually all LSDs. Studies within the past decade have drastically changed the notion that the lysosomes are merely the terminal degradative organelles. The emerging new roles of the lysosome include its central role in nutrient-dependent signal transduction regulating metabolism and cellular proliferation or quiescence. In this review, we first provide a brief overview of the endolysosomal and autophagic pathways, lysosomal acidification and endosome-lysosome and autophagosome-lysosome fusions. We emphasize the importance of these processes as their dysregulation leads to pathogenesis of many LSDs including the NCLs. We also describe what is currently known about each of the 13 CLN genes and their products and how understanding the emerging new roles of the lysosome may clarify the underlying pathogenic mechanisms of the NCLs. Finally, we discuss the current and emerging therapeutic strategies for various NCLs.
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Affiliation(s)
- Anil B. Mukherjee
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Abhilash P. Appu
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Tamal Sadhukhan
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Sydney Casey
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Avisek Mondal
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
| | - Zhongjian Zhang
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
- Present address: Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang, 453003 Henan China
| | - Maria B. Bagh
- Section on Developmental Genetics, Program on Endocrinology and Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892-1830 USA
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11
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Trepte P, Kruse S, Kostova S, Hoffmann S, Buntru A, Tempelmeier A, Secker C, Diez L, Schulz A, Klockmeier K, Zenkner M, Golusik S, Rau K, Schnoegl S, Garner CC, Wanker EE. LuTHy: a double-readout bioluminescence-based two-hybrid technology for quantitative mapping of protein-protein interactions in mammalian cells. Mol Syst Biol 2018; 14:e8071. [PMID: 29997244 PMCID: PMC6039870 DOI: 10.15252/msb.20178071] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 06/08/2018] [Accepted: 06/15/2018] [Indexed: 12/12/2022] Open
Abstract
Information on protein-protein interactions (PPIs) is of critical importance for studying complex biological systems and developing therapeutic strategies. Here, we present a double-readout bioluminescence-based two-hybrid technology, termed LuTHy, which provides two quantitative scores in one experimental procedure when testing binary interactions. PPIs are first monitored in cells by quantification of bioluminescence resonance energy transfer (BRET) and, following cell lysis, are again quantitatively assessed by luminescence-based co-precipitation (LuC). The double-readout procedure detects interactions with higher sensitivity than traditional single-readout methods and is broadly applicable, for example, for detecting the effects of small molecules or disease-causing mutations on PPIs. Applying LuTHy in a focused screen, we identified 42 interactions for the presynaptic chaperone CSPα, causative to adult-onset neuronal ceroid lipofuscinosis (ANCL), a progressive neurodegenerative disease. Nearly 50% of PPIs were found to be affected when studying the effect of the disease-causing missense mutations L115R and ∆L116 in CSPα with LuTHy. Our study presents a robust, sensitive research tool with high utility for investigating the molecular mechanisms by which disease-associated mutations impair protein activity in biological systems.
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Affiliation(s)
- Philipp Trepte
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Sabrina Kruse
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Simona Kostova
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Sheila Hoffmann
- Synaptopathy, German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Alexander Buntru
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Anne Tempelmeier
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Christopher Secker
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Lisa Diez
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Aline Schulz
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Konrad Klockmeier
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Martina Zenkner
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Sabrina Golusik
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Kirstin Rau
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Sigrid Schnoegl
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
| | - Craig C Garner
- Synaptopathy, German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Erich E Wanker
- Neuroproteomics, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, Berlin, Germany
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12
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Hasegawa T, Yoshida S, Sugeno N, Kobayashi J, Aoki M. DnaJ/Hsp40 Family and Parkinson's Disease. Front Neurosci 2018; 11:743. [PMID: 29367843 PMCID: PMC5767785 DOI: 10.3389/fnins.2017.00743] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease (PD) is the second most common devastating neurodegenerative disorder after Alzheimer's disease. The precise molecular and cellular basis underlying PD still remains uncertain; however, accumulating evidence suggests that neuronal cell death is caused by a combination of environmental and genetic factors. Over the previous two decades, more than 20 genes have been identified as the cause of and/or risk for PD. Because sporadic and familial forms of PD have many similarities in clinical and neuropathological features, common molecular pathways, such as aberrant mitochondrial and protein homeostasis, are likely to exist in both conditions. Of the various genes and proteins involved in PD, the versatile DnaJ/Hsp40 co-chaperones have attracted particular attention since several genes encoding this protein family have been successively identified as the cause of the familial forms of PD/Parkinsonism. In this review, we will introduce the current knowledge regarding the integratory and modulatory effect of DnaJ/Hsp40 in various cellular functions and argue how the failure of these proteins may initiate and/or facilitate of the disease.
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Affiliation(s)
- Takafumi Hasegawa
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shun Yoshida
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Naoto Sugeno
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Junpei Kobayashi
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masashi Aoki
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
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Candiello E, Mishra R, Schmidt B, Jahn O, Schu P. Differential regulation of synaptic AP-2/clathrin vesicle uncoating in synaptic plasticity. Sci Rep 2017; 7:15781. [PMID: 29150658 PMCID: PMC5694008 DOI: 10.1038/s41598-017-16055-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/24/2017] [Indexed: 11/09/2022] Open
Abstract
AP-1/σ1B-deficiency causes X-linked intellectual disability. AP-1/σ1B -/- mice have impaired synaptic vesicle recycling, fewer synaptic vesicles and enhanced endosome maturation mediated by AP-1/σ1A. Despite defects in synaptic vesicle recycling synapses contain two times more endocytic AP-2 clathrin-coated vesicles. We demonstrate increased formation of two classes of AP-2/clathrin coated vesicles. One which uncoats readily and a second with a stabilised clathrin coat. Coat stabilisation is mediated by three molecular mechanisms: reduced recruitment of Hsc70 and synaptojanin1 and enhanced μ2/AP-2 phosphorylation and activation. Stabilised AP-2 vesicles are enriched in the structural active zone proteins Git1 and stonin2 and synapses contain more Git1. Endocytosis of the synaptic vesicle exocytosis regulating Munc13 isoforms are differentially effected. Regulation of synaptic protein endocytosis by the differential stability of AP-2/clathrin coats is a novel molecular mechanism of synaptic plasticity.
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Affiliation(s)
- Ermes Candiello
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Ratnakar Mishra
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Bernhard Schmidt
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Olaf Jahn
- The Max-Planck-Institute for Experimental Medicine, Proteomics, Hermann-Rein-Str. 3, 37073, Göttingen, Germany
| | - Peter Schu
- Department of Cellular Biochemistry, University Medical Center Goettingen, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.
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14
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Primary fibroblasts from CSPα mutation carriers recapitulate hallmarks of the adult onset neuronal ceroid lipofuscinosis. Sci Rep 2017; 7:6332. [PMID: 28740222 PMCID: PMC5524943 DOI: 10.1038/s41598-017-06710-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 06/15/2017] [Indexed: 01/14/2023] Open
Abstract
Mutations in the co- chaperone protein, CSPα, cause an autosomal dominant, adult-neuronal ceroid lipofuscinosis (AD-ANCL). The current understanding of CSPα function exclusively at the synapse fails to explain the autophagy-lysosome pathway (ALP) dysfunction in cells from AD-ANCL patients. Here, we demonstrate unexpectedly that primary dermal fibroblasts from pre-symptomatic mutation carriers recapitulate in vitro features found in the brains of AD-ANCL patients including auto-fluorescent storage material (AFSM) accumulation, CSPα aggregates, increased levels of lysosomal proteins and lysosome enzyme activities. AFSM accumulation correlates with CSPα aggregation and both are susceptible to pharmacological modulation of ALP function. In addition, we demonstrate that endogenous CSPα is present in the lysosome-enriched fractions and co-localizes with lysosome markers in soma, neurites and synaptic boutons. Overexpression of CSPα wild-type (WT) decreases lysotracker signal, secreted lysosomal enzymes and SNAP23-mediated lysosome exocytosis. CSPα WT, mutant and aggregated CSPα are degraded mainly by the ALP but this disease-causing mutation exhibits a faster rate of degradation. Co-expression of both WT and mutant CSPα cause a block in the fusion of autophagosomes/lysosomes. Our data suggest that aggregation-dependent perturbation of ALP function is a relevant pathogenic mechanism for AD-ANCL and supports the use of AFSM or CSPα aggregation as biomarkers for drug screening purposes.
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15
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Lopez-Ortega E, Ruiz R, Tabares L. CSPα, a Molecular Co-chaperone Essential for Short and Long-Term Synaptic Maintenance. Front Neurosci 2017; 11:39. [PMID: 28239331 PMCID: PMC5301022 DOI: 10.3389/fnins.2017.00039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 01/19/2017] [Indexed: 01/26/2023] Open
Abstract
Cysteine string protein α (CSPα) is a vesicle protein located in the presynaptic terminal of most synapses. CSPα is an essential molecular co-chaperone that facilitates the correct folding of proteins and the assembly of the exocytic machinery. The absence of this protein leads to altered neurotransmitter release and neurodegeneration in multiple model systems, from flies to mice. In humans, CSPα mutations are associated with the development of neuronal ceroid lipofuscinosis (NCL), a neurodegenerative disease characterized by intracellular accumulation of lysosomal material. Here, we review the physiological role of CSPα and the pathology resulting from the homozygous deletion of the gene or its mutations. In addition, we investigate whether long-term moderate reduction of the protein produces motor dysfunction. We found that 1-year-old CSPα heterozygous mice display a reduced ability to sustain motor unit recruitment during repetitive stimulation, which indicates that physiological levels of CSPα are required for normal neuromuscular responses in mice and, likely, in humans.
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Affiliation(s)
- Elena Lopez-Ortega
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville Seville, Spain
| | - Rocío Ruiz
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Seville Seville, Spain
| | - Lucia Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville Seville, Spain
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16
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Lin SY, Vollrath MA, Mangosing S, Shen J, Cardenas E, Corey DP. The zebrafish pinball wizard gene encodes WRB, a tail-anchored-protein receptor essential for inner-ear hair cells and retinal photoreceptors. J Physiol 2015; 594:895-914. [PMID: 26593130 DOI: 10.1113/jp271437] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/17/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The zebrafish pinball wizard (pwi) mutant is deaf and blind. The pwi phenotype includes a reduced auditory startle response and reduced visual evoked potentials, suggesting fatigue of synaptic release at ribbon synapses in hair cells and photoreceptors. The gene defective in the pwi mutant is WRB, a protein homologous to the yeast protein Get1, which is involved in the insertion of 'tail-anchored' membrane proteins. Many tail-anchored proteins are associated with synaptic vesicles, and both vesicles and synaptic ribbons are reduced in synaptic regions of hair cells in pwi. Abnormal processing of synaptic vesicle proteins important for ribbon synapses can explain the pwi phenotype. ABSTRACT In a large-scale zebrafish insertional mutagenesis screen, we identified the pinball wizard (pwi) line, which displays a deafness and blindness phenotype. Although the gross morphology and structure of the pwi larval inner ear was near normal, acoustic startle stimuli evoked smaller postsynaptic responses in afferent neurons, which rapidly fatigued. In the retina, similarly, an abnormal electroretinogram suggested reduced transmission at the photoreceptor ribbon synapse. A functional deficit in these specialized synapses was further supported by a reduction of synaptic marker proteins Rab3 and cysteine-string protein (CSP/Dnajc5) in hair cells and photoreceptors, as well as by a reduction of the number of both ribbons and vesicles surrounding the ribbons in hair cells. The pwi gene encodes a homologue of the yeast Get1 and human tryptophan-rich basic (WRB) proteins, which are receptors for membrane insertion of tail-anchored (TA) proteins. We identified more than 100 TA proteins expressed in hair cells, including many synaptic proteins. The expression of synaptobrevin and syntaxin 3, TA proteins essential for vesicle fusion, was reduced in the synaptic layers of mutant retina, consistent with a role for the pwi/WRB protein in TA-protein processing. The WRB protein was located near the apical domain and the ribbons in hair cells, and in the inner segment and the axon of the photoreceptor, consistent with a role in vesicle biogenesis or trafficking. Taken together, our results suggest that WRB plays a critical role in synaptic functions in these two sensory cells, and that disrupted processing of synaptic vesicle TA proteins explains much of the mutant phenotype.
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Affiliation(s)
- Shuh-Yow Lin
- Department of Surgery, UC San Diego School of Medicine, La Jolla, CA, USA
| | - Melissa A Vollrath
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Sara Mangosing
- Department of Surgery, UC San Diego School of Medicine, La Jolla, CA, USA
| | - Jun Shen
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Elena Cardenas
- Department of Surgery, UC San Diego School of Medicine, La Jolla, CA, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
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17
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Benitez BA, Cairns NJ, Schmidt RE, Morris JC, Norton JB, Cruchaga C, Sands MS. Clinically early-stage CSPα mutation carrier exhibits remarkable terminal stage neuronal pathology with minimal evidence of synaptic loss. Acta Neuropathol Commun 2015; 3:73. [PMID: 26610600 PMCID: PMC4660676 DOI: 10.1186/s40478-015-0256-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/13/2015] [Indexed: 01/18/2023] Open
Abstract
Autosomal dominant adult-onset neuronal ceroid lipofuscinosis (AD-ANCL) is a multisystem disease caused by mutations in the DNAJC5 gene. DNAJC5 encodes Cysteine String Protein-alpha (CSPα), a putative synaptic protein. AD-ANCL has been traditionally considered a lysosomal storage disease based on the intracellular accumulation of ceroid material. Here, we report for the first time the pathological findings of a patient in a clinically early stage of disease, which exhibits the typical neuronal intracellular ceroid accumulation and incipient neuroinflammation but no signs of brain atrophy, neurodegeneration or massive synaptic loss. Interestingly, we found minimal or no apparent reductions in CSPα or synaptophysin in the neuropil. In contrast, brain homogenates from terminal AD-ANCL patients exhibit significant reductions in SNARE-complex forming presynaptic protein levels, including a significant reduction in CSPα and SNAP-25. Frozen samples for the biochemical analyses of synaptic proteins were not available for the early stage AD-ANLC patient. These results suggest that the degeneration seen in the patients with AD-ANCL reported here might be a consequence of both the early effects of CSPα mutations at the cellular soma, most likely lysosome function, and subsequent neuronal loss and synaptic dysfunction.
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18
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Sturgeon M, Davis D, Albers A, Beatty D, Austin R, Ferguson M, Tounsel B, Liebl FLW. The Notch ligand E3 ligase, Mind Bomb1, regulates glutamate receptor localization in Drosophila. Mol Cell Neurosci 2015; 70:11-21. [PMID: 26596173 DOI: 10.1016/j.mcn.2015.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 11/09/2015] [Accepted: 11/16/2015] [Indexed: 12/29/2022] Open
Abstract
The postsynaptic density (PSD) is a protein-rich network important for the localization of postsynaptic glutamate receptors (GluRs) and for signaling downstream of these receptors. Although hundreds of PSD proteins have been identified, many are functionally uncharacterized. We conducted a reverse genetic screen for mutations that affected GluR localization using Drosophila genes that encode homologs of mammalian PSD proteins. 42.8% of the mutants analyzed exhibited a significant change in GluR localization at the third instar larval neuromuscular junction (NMJ), a model synapse that expresses homologs of AMPA receptors. We identified the E3 ubiquitin ligase, Mib1, which promotes Notch signaling, as a regulator of synaptic GluR localization. Mib1 positively regulates the localization of the GluR subunits GluRIIA, GluRIIB, and GluRIIC. Mutations in mib1 and ubiquitous expression of Mib1 that lacks its ubiquitin ligase activity result in the loss of synaptic GluRIIA-containing receptors. In contrast, overexpression of Mib1 in all tissues increases postsynaptic levels of GluRIIA. Cellular levels of Mib1 are also important for the structure of the presynaptic motor neuron. While deficient Mib1 signaling leads to overgrowth of the NMJ, ubiquitous overexpression of Mib1 results in a reduction in the number of presynaptic motor neuron boutons and branches. These synaptic changes may be secondary to attenuated glutamate release from the presynaptic motor neuron in mib1 mutants as mib1 mutants exhibit significant reductions in the vesicle-associated protein cysteine string protein and in the frequency of spontaneous neurotransmission.
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Affiliation(s)
- Morgan Sturgeon
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Dustin Davis
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Amanda Albers
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Derek Beatty
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Rik Austin
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Matt Ferguson
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Brittany Tounsel
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Faith L W Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States.
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19
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Donnelier J, Braun ST, Dolzhanskaya N, Ahrendt E, Braun AP, Velinov M, Braun JEA. Increased Expression of the Large Conductance, Calcium-Activated K+ (BK) Channel in Adult-Onset Neuronal Ceroid Lipofuscinosis. PLoS One 2015; 10:e0125205. [PMID: 25905915 PMCID: PMC4407904 DOI: 10.1371/journal.pone.0125205] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/17/2015] [Indexed: 01/18/2023] Open
Abstract
Cysteine string protein (CSPα) is a presynaptic J protein co-chaperone that opposes neurodegeneration. Mutations in CSPα (i.e., Leu115 to Arg substitution or deletion (Δ) of Leu116) cause adult neuronal ceroid lipofuscinosis (ANCL), a dominantly inherited neurodegenerative disease. We have previously demonstrated that CSPα limits the expression of large conductance, calcium-activated K+ (BK) channels in neurons, which may impact synaptic excitability and neurotransmission. Here we show by western blot analysis that expression of the pore-forming BKα subunit is elevated ~2.5 fold in the post-mortem cortex of a 36-year-old patient with the Leu116∆ CSPα mutation. Moreover, we find that the increase in BKα subunit level is selective for ANCL and not a general feature of neurodegenerative conditions. While reduced levels of CSPα are found in some postmortem cortex specimens from Alzheimer's disease patients, we find no concomitant increase in BKα subunit expression in Alzheimer's specimens. Both CSPα monomer and oligomer expression are reduced in synaptosomes prepared from ANCL cortex compared with control. In a cultured neuronal cell model, CSPα oligomers are short lived. The results of this study indicate that the Leu116∆ mutation leads to elevated BKα subunit levels in human cortex and extend our initial work in rodent models demonstrating the modulation of BKα subunit levels by the same CSPα mutation. While the precise sequence of pathogenic events still remains to be elucidated, our findings suggest that dysregulation of BK channels may contribute to neurodegeneration in ANCL.
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Affiliation(s)
- Julien Donnelier
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Samuel T. Braun
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | - Eva Ahrendt
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew P. Braun
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Milen Velinov
- Albert Einstein College of Medicine, Bronx, New York, United States of America
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Janice E. A. Braun
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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20
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Brusich DJ, Spring AM, Frank CA. A single-cross, RNA interference-based genetic tool for examining the long-term maintenance of homeostatic plasticity. Front Cell Neurosci 2015; 9:107. [PMID: 25859184 PMCID: PMC4374470 DOI: 10.3389/fncel.2015.00107] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/09/2015] [Indexed: 11/15/2022] Open
Abstract
Homeostatic synaptic plasticity (HSP) helps neurons and synapses maintain physiologically appropriate levels of output. The fruit fly Drosophila melanogaster larval neuromuscular junction (NMJ) is a valuable model for studying HSP. Here we introduce a genetic tool that allows fruit fly researchers to examine the lifelong maintenance of HSP with a single cross. The tool is a fruit fly stock that combines the GAL4/UAS expression system with RNA interference (RNAi)-based knock down of a glutamate receptor subunit gene. With this stock, we uncover important new information about the maintenance of HSP. We address an open question about the role that presynaptic CaV2-type Ca2+ channels play in NMJ homeostasis. Published experiments have demonstrated that hypomorphic missense mutations in the CaV2 α1a subunit gene cacophony (cac) can impair homeostatic plasticity at the NMJ. Here we report that reducing cac expression levels by RNAi is not sufficient to impair homeostatic plasticity. The presence of wild-type channels appears to support HSP—even when total CaV2 function is severely reduced. We also conduct an RNAi- and electrophysiology-based screen to identify new factors required for sustained homeostatic signaling throughout development. We uncover novel roles in HSP for Drosophila homologs of Cysteine string protein (CSP) and Phospholipase Cβ (Plc21C). We characterize those roles through follow-up genetic tests. We discuss how CSP, Plc21C, and associated factors could modulate presynaptic CaV2 function, presynaptic Ca2+ handling, or other signaling processes crucial for sustained homeostatic regulation of NMJ function throughout development. Our findings expand the scope of signaling pathways and processes that contribute to the durable strength of the NMJ.
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Affiliation(s)
- Douglas J Brusich
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa Iowa City, IA, USA
| | - Ashlyn M Spring
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa Iowa City, IA, USA ; Interdisciplinary Graduate Program in Genetics, University of Iowa Iowa City, IA, USA
| | - C Andrew Frank
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa Iowa City, IA, USA ; Interdisciplinary Programs in Genetics, Neuroscience, and MCB, University of Iowa Iowa City, IA, USA
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21
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Swayne LA, Altier C, Zamponi GW. The truth in complexes: perspectives on ion channel signaling nexuses in the nervous system. Front Cell Neurosci 2014; 8:406. [PMID: 25505383 PMCID: PMC4244691 DOI: 10.3389/fncel.2014.00406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/10/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- Leigh A Swayne
- Island Medical Program, Division of Medical Sciences, University of Victoria Victoria, BC, Canada ; Department of Biology, University of Victoria Victoria, BC, Canada ; Department of Cellular and Physiological Sciences, University of British Columbia Vancouver, BC, Canada
| | - Christophe Altier
- Department of Physiology and Pharmacology, University of Calgary Calgary, AB, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, University of Calgary Calgary, AB, Canada
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22
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Kyle BD, Braun AP. The regulation of BK channel activity by pre- and post-translational modifications. Front Physiol 2014; 5:316. [PMID: 25202279 PMCID: PMC4141542 DOI: 10.3389/fphys.2014.00316] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/02/2014] [Indexed: 11/17/2022] Open
Abstract
Large conductance, Ca2+-activated K+ (BK) channels represent an important pathway for the outward flux of K+ ions from the intracellular compartment in response to membrane depolarization, and/or an elevation in cytosolic free [Ca2+]. They are functionally expressed in a range of mammalian tissues (e.g., nerve and smooth muscles), where they can either enhance or dampen membrane excitability. The diversity of BK channel activity results from the considerable alternative mRNA splicing and post-translational modification (e.g., phosphorylation) of key domains within the pore-forming α subunit of the channel complex. Most of these modifications are regulated by distinct upstream cell signaling pathways that influence the structure and/or gating properties of the holo-channel and ultimately, cellular function. The channel complex may also contain auxiliary subunits that further affect channel gating and behavior, often in a tissue-specific manner. Recent studies in human and animal models have provided strong evidence that abnormal BK channel expression/function contributes to a range of pathologies in nerve and smooth muscle. By targeting the upstream regulatory events modulating BK channel behavior, it may be possible to therapeutically intervene and alter BK channel expression/function in a beneficial manner.
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Affiliation(s)
- Barry D Kyle
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Research Institute, University of Calgary Calgary, AB, Canada
| | - Andrew P Braun
- Department of Physiology and Pharmacology, Cumming School of Medicine, Libin Cardiovascular Research Institute, University of Calgary Calgary, AB, Canada
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23
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Koutras C, Braun JEA. J protein mutations and resulting proteostasis collapse. Front Cell Neurosci 2014; 8:191. [PMID: 25071450 PMCID: PMC4086201 DOI: 10.3389/fncel.2014.00191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/21/2014] [Indexed: 01/20/2023] Open
Abstract
Despite a century of intensive investigation the effective treatment of protein aggregation diseases remains elusive. Ordinarily, molecular chaperones ensure that proteins maintain their functional conformation. The appearance of misfolded proteins that aggregate implies the collapse of the cellular chaperone quality control network. That said, the cellular chaperone network is extensive and functional information regarding the detailed action of specific chaperones is not yet available. J proteins (DnaJ/Hsp40) are a family of chaperone cofactors that harness Hsc70 (heat shock cognate protein of 70 kDa) for diverse conformational cellular tasks and, as such, represent novel clinically relevant targets for diseases resulting from the disruption of proteostasis. Here we review incisive reports identifying mutations in individual J protein chaperones and the proteostasis collapse that ensues.
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Affiliation(s)
- Carolina Koutras
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of CalgaryCalgary, AB, Canada
| | - Janice E. A. Braun
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of CalgaryCalgary, AB, Canada
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