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Guiberson NGL, Black LS, Haller JE, Brukner A, Abramov D, Ahmad S, Xie YX, Sharma M, Burré J. Disease-linked mutations in Munc18-1 deplete synaptic Doc2. Brain 2024; 147:2185-2202. [PMID: 38242640 PMCID: PMC11146428 DOI: 10.1093/brain/awae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/20/2023] [Accepted: 01/09/2024] [Indexed: 01/21/2024] Open
Abstract
Heterozygous de novo mutations in the neuronal protein Munc18-1/STXBP1 cause syndromic neurological symptoms, including severe epilepsy, intellectual disability, developmental delay, ataxia and tremor, summarized as STXBP1 encephalopathies. Although haploinsufficiency is the prevailing disease mechanism, it remains unclear how the reduction in Munc18-1 levels causes synaptic dysfunction in disease as well as how haploinsufficiency alone can account for the significant heterogeneity among patients in terms of the presence, onset and severity of different symptoms. Using biochemical and cell biological readouts on mouse brains, cultured mouse neurons and heterologous cells, we found that the synaptic Munc18-1 interactors Doc2A and Doc2B are unstable in the absence of Munc18-1 and aggregate in the presence of disease-causing Munc18-1 mutants. In haploinsufficiency-mimicking heterozygous knockout neurons, we found a reduction in Doc2A/B levels that is further aggravated by the presence of the disease-causing Munc18-1 mutation G544D as well as an impairment in Doc2A/B synaptic targeting in both genotypes. We also demonstrated that overexpression of Doc2A/B partially rescues synaptic dysfunction in heterozygous knockout neurons but not heterozygous knockout neurons expressing G544D Munc18-1. Our data demonstrate that STXBP1 encephalopathies are not only characterized by the dysfunction of Munc18-1 but also by the dysfunction of the Munc18-1 binding partners Doc2A and Doc2B, and that this dysfunction is exacerbated by the presence of a Munc18-1 missense mutant. These findings may offer a novel explanation for the significant heterogeneity in symptoms observed among STXBP1 encephalopathy patients.
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Affiliation(s)
- Noah Guy Lewis Guiberson
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Luca S Black
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jillian E Haller
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Aniv Brukner
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Debra Abramov
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Saad Ahmad
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Yan Xin Xie
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Manu Sharma
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jacqueline Burré
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
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2
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Bertin F, Jara-Wilde J, Auer B, Köhler-Solís A, González-Silva C, Thomas U, Sierralta J. Drosophila Atlastin regulates synaptic vesicle mobilization independent of bone morphogenetic protein signaling. Biol Res 2023; 56:49. [PMID: 37710314 PMCID: PMC10503011 DOI: 10.1186/s40659-023-00462-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND The endoplasmic reticulum (ER) contacts endosomes in all parts of a motor neuron, including the axon and presynaptic terminal, to move structural proteins, proteins that send signals, and lipids over long distances. Atlastin (Atl), a large GTPase, is required for membrane fusion and the structural dynamics of the ER tubules. Atl mutations are the second most common cause of Hereditary Spastic Paraplegia (HSP), which causes spasticity in both sexes' lower extremities. Through an unknown mechanism, Atl mutations stimulate the BMP (bone morphogenetic protein) pathway in vertebrates and Drosophila. Synaptic defects are caused by atl mutations, which affect the abundance and distribution of synaptic vesicles (SV) in the bouton. We hypothesize that BMP signaling, does not cause Atl-dependent SV abnormalities in Drosophila. RESULTS We show that atl knockdown in motor neurons (Atl-KD) increases synaptic and satellite boutons in the same way that constitutively activating the BMP-receptor Tkv (thick veins) (Tkv-CA) increases the bouton number. The SV proteins Cysteine string protein (CSP) and glutamate vesicular transporter are reduced in Atl-KD and Tkv-CA larvae. Reducing the activity of the BMP receptor Wishful thinking (wit) can rescue both phenotypes. Unlike Tkv-CA larvae, Atl-KD larvae display altered activity-dependent distributions of CSP staining. Furthermore, Atl-KD larvae display an increased FM 1-43 unload than Control and Tkv-CA larvae. As decreasing wit function does not reduce the phenotype, our hypothesis that BMP signaling is not involved is supported. We also found that Rab11/CSP colocalization increased in Atl-KD larvae, which supports the concept that late recycling endosomes regulate SV movements. CONCLUSIONS Our findings reveal that Atl modulates neurotransmitter release in motor neurons via SV distribution independently of BMP signaling, which could explain the observed SV accumulation and synaptic dysfunction. Our data suggest that Atl is involved in membrane traffic as well as formation and/or recycling of the late endosome.
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Affiliation(s)
- Francisca Bertin
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Jorge Jara-Wilde
- SCIAN-Lab, Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Computational Sciences, Faculty of Physical and Mathematical Sciences, Universidad de Chile, Santiago, Chile
| | - Benedikt Auer
- Laboratory of Neuronal and Synaptic Signals, Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Andrés Köhler-Solís
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Carolina González-Silva
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Ulrich Thomas
- Functional Genetics of the Synapse, Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
| | - Jimena Sierralta
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.
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Carnazza KE, Komer LE, Xie YX, Pineda A, Briano JA, Gao V, Na Y, Ramlall T, Buchman VL, Eliezer D, Sharma M, Burré J. Synaptic vesicle binding of α-synuclein is modulated by β- and γ-synucleins. Cell Rep 2022; 39:110675. [PMID: 35417693 PMCID: PMC9116446 DOI: 10.1016/j.celrep.2022.110675] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 01/23/2022] [Accepted: 03/22/2022] [Indexed: 12/16/2022] Open
Abstract
α-synuclein, β-synuclein, and γ-synuclein are abundantly expressed proteins in the vertebrate nervous system. α-synuclein functions in neurotransmitter release by binding to and clustering synaptic vesicles and chaperoning SNARE-complex assembly. Pathologically, aggregates originating from soluble pools of α-synuclein are deposited into Lewy bodies in Parkinson's disease and related synucleinopathies. The functions of β-synuclein and γ-synuclein in presynaptic terminals remain poorly studied. Using in vitro liposome binding studies, circular dichroism spectroscopy, immunoprecipitation, and fluorescence resonance energy transfer (FRET) experiments on isolated synaptic vesicles in combination with subcellular fractionation of brains from synuclein mouse models, we show that β-synuclein and γ-synuclein have a reduced affinity toward synaptic vesicles compared with α-synuclein, and that heteromerization of β-synuclein or γ-synuclein with α-synuclein results in reduced synaptic vesicle binding of α-synuclein in a concentration-dependent manner. Our data suggest that β-synuclein and γ-synuclein are modulators of synaptic vesicle binding of α-synuclein and thereby reduce α-synuclein's physiological activity at the neuronal synapse.
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Affiliation(s)
- Kathryn E Carnazza
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lauren E Komer
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Ying Xue Xie
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - André Pineda
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Juan Antonio Briano
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Virginia Gao
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Yoonmi Na
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Trudy Ramlall
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Vladimir L Buchman
- School of Biosciences, Cardiff University, Cardiff CF103AX, UK; Belgorod State National Research University, 85 Pobedy Street, Belgorod, Belgorod 308015, Russian Federation
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Manu Sharma
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jacqueline Burré
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA.
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Ninkina N, Millership SJ, Peters OM, Connor-Robson N, Chaprov K, Kopylov AT, Montoya A, Kramer H, Withers DJ, Buchman VL. β-synuclein potentiates synaptic vesicle dopamine uptake and rescues dopaminergic neurons from MPTP-induced death in the absence of other synucleins. J Biol Chem 2021; 297:101375. [PMID: 34736896 PMCID: PMC8633583 DOI: 10.1016/j.jbc.2021.101375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/20/2021] [Accepted: 10/28/2021] [Indexed: 12/11/2022] Open
Abstract
Synucleins, a family of three proteins highly expressed in neurons, are predominantly known for the direct involvement of α-synuclein in the etiology and pathogenesis of Parkinson's and certain other neurodegenerative diseases, but their precise physiological functions are still not fully understood. Previous studies have demonstrated the importance of α-synuclein as a modulator of various mechanisms implicated in chemical neurotransmission, but information concerning the involvement of other synuclein family members, β-synuclein and γ-synuclein, in molecular processes within presynaptic terminals is limited. Here, we demonstrated that the vesicular monoamine transporter 2-dependent dopamine uptake by synaptic vesicles isolated from the striatum of mice lacking β-synuclein is significantly reduced. Reciprocally, reintroduction, either in vivo or in vitro, of β-synuclein but not α-synuclein or γ-synuclein improves uptake by triple α/β/γ-synuclein-deficient striatal vesicles. We also showed that the resistance of dopaminergic neurons of the substantia nigra pars compacta to subchronic administration of the Parkinson's disease-inducing prodrug 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine depends on the presence of β-synuclein but only when one or both other synucleins are absent. Furthermore, proteomic analysis of synuclein-deficient synaptic vesicles versus those containing only β-synuclein revealed differences in their protein compositions. We suggest that the observed potentiation of dopamine uptake by β-synuclein might be caused by different protein architecture of the synaptic vesicles. It is also feasible that such structural changes improve synaptic vesicle sequestration of 1-methyl-4-phenylpyridinium, a toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, which would explain why dopaminergic neurons expressing β-synuclein and lacking α-synuclein and/or γ-synuclein are resistant to this neurotoxin.
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Affiliation(s)
- Natalia Ninkina
- School of Biosciences, Cardiff University, Cardiff, United Kingdom; Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russian Federation
| | - Steven J Millership
- School of Biosciences, Cardiff University, Cardiff, United Kingdom; Metabolic Signalling, MRC London Institute of Medical Sciences, London, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Owen M Peters
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Kirill Chaprov
- School of Biosciences, Cardiff University, Cardiff, United Kingdom; Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russian Federation
| | - Arthur T Kopylov
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russian Federation
| | - Alex Montoya
- Metabolic Signalling, MRC London Institute of Medical Sciences, London, United Kingdom
| | - Holger Kramer
- Metabolic Signalling, MRC London Institute of Medical Sciences, London, United Kingdom
| | - Dominic J Withers
- Metabolic Signalling, MRC London Institute of Medical Sciences, London, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Vladimir L Buchman
- School of Biosciences, Cardiff University, Cardiff, United Kingdom; Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russian Federation.
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5
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O'Neil SD, Rácz B, Brown WE, Gao Y, Soderblom EJ, Yasuda R, Soderling SH. Action potential-coupled Rho GTPase signaling drives presynaptic plasticity. eLife 2021; 10:63756. [PMID: 34269176 PMCID: PMC8285108 DOI: 10.7554/elife.63756] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 07/06/2021] [Indexed: 12/30/2022] Open
Abstract
In contrast to their postsynaptic counterparts, the contributions of activity-dependent cytoskeletal signaling to presynaptic plasticity remain controversial and poorly understood. To identify and evaluate these signaling pathways, we conducted a proteomic analysis of the presynaptic cytomatrix using in vivo biotin identification (iBioID). The resultant proteome was heavily enriched for actin cytoskeleton regulators, including Rac1, a Rho GTPase that activates the Arp2/3 complex to nucleate branched actin filaments. Strikingly, we find Rac1 and Arp2/3 are closely associated with synaptic vesicle membranes in adult mice. Using three independent approaches to alter presynaptic Rac1 activity (genetic knockout, spatially restricted inhibition, and temporal optogenetic manipulation), we discover that this pathway negatively regulates synaptic vesicle replenishment at both excitatory and inhibitory synapses, bidirectionally sculpting short-term synaptic depression. Finally, we use two-photon fluorescence lifetime imaging to show that presynaptic Rac1 activation is coupled to action potentials by voltage-gated calcium influx. Thus, this study uncovers a previously unrecognized mechanism of actin-regulated short-term presynaptic plasticity that is conserved across excitatory and inhibitory terminals. It also provides a new proteomic framework for better understanding presynaptic physiology, along with a blueprint of experimental strategies to isolate the presynaptic effects of ubiquitously expressed proteins.
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Affiliation(s)
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Walter Evan Brown
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Yudong Gao
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Erik J Soderblom
- Department of Cell Biology, Duke University Medical Center, Durham, United States.,Proteomics and Metabolomics Shared Resource and Center for Genomic and Computational Biology, Duke University Medical Center, Durham, United States
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Scott H Soderling
- Department of Neurobiology, Duke University Medical Center, Durham, United States.,Department of Cell Biology, Duke University Medical Center, Durham, United States
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6
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A unified resource and configurable model of the synapse proteome and its role in disease. Sci Rep 2021; 11:9967. [PMID: 33976238 PMCID: PMC8113277 DOI: 10.1038/s41598-021-88945-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/15/2021] [Indexed: 02/03/2023] Open
Abstract
Genes encoding synaptic proteins are highly associated with neuronal disorders many of which show clinical co-morbidity. We integrated 58 published synaptic proteomic datasets that describe over 8000 proteins and combined them with direct protein-protein interactions and functional metadata to build a network resource that reveals the shared and unique protein components that underpin multiple disorders. All the data are provided in a flexible and accessible format to encourage custom use.
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7
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Wittig S, Ganzella M, Barth M, Kostmann S, Riedel D, Pérez-Lara Á, Jahn R, Schmidt C. Cross-linking mass spectrometry uncovers protein interactions and functional assemblies in synaptic vesicle membranes. Nat Commun 2021; 12:858. [PMID: 33558502 PMCID: PMC7870876 DOI: 10.1038/s41467-021-21102-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/18/2020] [Indexed: 02/08/2023] Open
Abstract
Synaptic vesicles are storage organelles for neurotransmitters. They pass through a trafficking cycle and fuse with the pre-synaptic membrane when an action potential arrives at the nerve terminal. While molecular components and biophysical parameters of synaptic vesicles have been determined, our knowledge on the protein interactions in their membranes is limited. Here, we apply cross-linking mass spectrometry to study interactions of synaptic vesicle proteins in an unbiased approach without the need for specific antibodies or detergent-solubilisation. Our large-scale analysis delivers a protein network of vesicle sub-populations and functional assemblies including an active and an inactive conformation of the vesicular ATPase complex as well as non-conventional arrangements of the luminal loops of SV2A, Synaptophysin and structurally related proteins. Based on this network, we specifically target Synaptobrevin-2, which connects with many proteins, in different approaches. Our results allow distinction of interactions caused by 'crowding' in the vesicle membrane from stable interaction modules.
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Affiliation(s)
- Sabine Wittig
- Interdisciplinary Research Centre HALOmem, Charles Tanford Protein Centre, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Marcelo Ganzella
- Department for Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marie Barth
- Interdisciplinary Research Centre HALOmem, Charles Tanford Protein Centre, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Susann Kostmann
- Interdisciplinary Research Centre HALOmem, Charles Tanford Protein Centre, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Dietmar Riedel
- Department for Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ángel Pérez-Lara
- Department for Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Reinhard Jahn
- Department for Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Carla Schmidt
- Interdisciplinary Research Centre HALOmem, Charles Tanford Protein Centre, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany.
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8
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Akula AK, Zhang X, Viotti JS, Nestvogel D, Rhee JS, Ebrecht R, Reim K, Wouters F, Liepold T, Jahn O, Bogeski I, Dresbach T. The Calmodulin Binding Region of the Synaptic Vesicle Protein Mover Is Required for Homomeric Interaction and Presynaptic Targeting. Front Mol Neurosci 2019; 12:249. [PMID: 31787876 PMCID: PMC6856015 DOI: 10.3389/fnmol.2019.00249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 09/26/2019] [Indexed: 01/10/2023] Open
Abstract
Neurotransmitter release is mediated by an evolutionarily conserved machinery. The synaptic vesicle (SV) associated protein Mover/TPRGL/SVAP30 does not occur in all species and all synapses. Little is known about its molecular properties and how it may interact with the conserved components of the presynaptic machinery. Here, we show by deletion analysis that regions required for homomeric interaction of Mover are distributed across the entire molecule, including N-terminal, central and C-terminal regions. The same regions are also required for the accumulation of Mover in presynaptic terminals of cultured neurons. Mutating two phosphorylation sites in N-terminal regions did not affect these properties. In contrast, a point mutation in the predicted Calmodulin (CaM) binding sequence of Mover abolished both homomeric interaction and presynaptic targeting. We show that this sequence indeed binds Calmodulin, and that recombinant Mover increases Calmodulin signaling upon heterologous expression. Our data suggest that presynaptic accumulation of Mover requires homomeric interaction mediated by regions distributed across large areas of the protein, and corroborate the hypothesis that Mover functionally interacts with Calmodulin signaling.
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Affiliation(s)
- Asha Kiran Akula
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany
| | - Xin Zhang
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Göttingen, Germany
| | - Julio S Viotti
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany
| | - Dennis Nestvogel
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jeong-Seop Rhee
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Rene Ebrecht
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Kerstin Reim
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Fred Wouters
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Thomas Liepold
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Göttingen, Germany
| | - Thomas Dresbach
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany
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9
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Furber KL, Backlund PS, Yergey AL, Coorssen JR. Unbiased Thiol-Labeling and Top-Down Proteomic Analyses Implicate Multiple Proteins in the Late Steps of Regulated Secretion. Proteomes 2019; 7:proteomes7040034. [PMID: 31569819 PMCID: PMC6958363 DOI: 10.3390/proteomes7040034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022] Open
Abstract
Regulated exocytosis enables temporal and spatial control over the secretion of biologically active compounds; however, the mechanism by which Ca2+ modulates different stages of exocytosis is still poorly understood. For an unbiased, top-down proteomic approach, select thiol- reactive reagents were used to investigate this process in release-ready native secretory vesicles. We previously characterized a biphasic effect of these reagents on Ca2+-triggered exocytosis: low doses potentiated Ca2+ sensitivity, whereas high doses inhibited Ca2+ sensitivity and extent of vesicle fusion. Capitalizing on this novel potentiating effect, we have now identified fluorescent thiol- reactive reagents producing the same effects: Lucifer yellow iodoacetamide, monobromobimane, and dibromobimane. Top-down proteomic analyses of fluorescently labeled proteins from total and cholesterol-enriched vesicle membrane fractions using two-dimensional gel electrophoresis coupled with mass spectrometry identified several candidate targets, some of which have been previously linked to the late steps of regulated exocytosis and some of which are novel. Initial validation studies indicate that Rab proteins are involved in the modulation of Ca2+ sensitivity, and thus the efficiency of membrane fusion, which may, in part, be linked to their previously identified upstream roles in vesicle docking.
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Affiliation(s)
- Kendra L Furber
- Northern Medical Program, University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada.
| | - Peter S Backlund
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Alfred L Yergey
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jens R Coorssen
- Department of Health Sciences, Faculty of Applied Health Sciences and Department of Biological Sciences, Faculty of Mathematics & Science, Brock University, St. Catharines, ON L2S 3A1, Canada.
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10
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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12
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Salgado-Mendialdúa V, Aguirre-Plans J, Guney E, Reig-Viader R, Maldonado R, Bayés À, Oliva B, Ozaita A. Δ9-tetrahydrocannabinol modulates the proteasome system in the brain. Biochem Pharmacol 2018; 157:159-168. [PMID: 30134192 DOI: 10.1016/j.bcp.2018.08.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/17/2018] [Indexed: 12/22/2022]
Abstract
Cannabis is the most consumed illicit drug worldwide. Its principal psychoactive component, Δ9-tetrahydrocannabinol (THC), affects multiple brain functions, including cognitive performance, by modulating cannabinoid type-1 (CB1) receptors. These receptors are strongly enriched in presynaptic terminals, where they modulate neurotransmitter release. We analyzed, through a proteomic screening of hippocampal synaptosomal fractions, those proteins and pathways modulated 3 h after a single administration of an amnesic dose of THC (10 mg/kg, i.p.). Using an isobaric labeling approach, we identified 2040 proteins, 1911 of them previously reported in synaptic proteomes, confirming the synaptic content enrichment of the samples. Initial analysis revealed a significant alteration of 122 proteins, where 42 increased and 80 decreased their expression. Gene set enrichment analysis indicated an over-representation of mitochondrial associated functions and cellular metabolic processes. A second analysis focusing on extreme changes revealed 28 proteins with altered expression after THC treatment, 15 of them up-regulated and 13 down-regulated. Using a network topology-based scoring algorithm we identified those proteins in the mouse proteome with the greatest association to the 28 modulated proteins. This analysis pinpointed a significant alteration of the proteasome function, since top scoring proteins were related to the proteasome system (PS), a protein complex involved in ATP-dependent protein degradation. In this regard, we observed that THC decreases 20S proteasome chymotrypsin-like protease activity in the hippocampus. Our data describe for the first time the modulation of the PS in the hippocampus following THC administration under amnesic conditions that may contribute to an aberrant plasticity at synapses.
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Affiliation(s)
- V Salgado-Mendialdúa
- Laboratory of Neuropharmacology, Dept. Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain
| | - J Aguirre-Plans
- Structural Bioinformatics Laboratory, Biomedical Informatics Research Unit, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain
| | - E Guney
- Structural Bioinformatics Laboratory, Biomedical Informatics Research Unit, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain
| | - R Reig-Viader
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau (IIB Sant Pau), Sant Antoni Maria Claret 167, 08025 Barcelona, Spain; Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Bellaterra, Spain
| | - R Maldonado
- Laboratory of Neuropharmacology, Dept. Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain
| | - À Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau (IIB Sant Pau), Sant Antoni Maria Claret 167, 08025 Barcelona, Spain; Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Bellaterra, Spain
| | - B Oliva
- Structural Bioinformatics Laboratory, Biomedical Informatics Research Unit, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain
| | - A Ozaita
- Laboratory of Neuropharmacology, Dept. Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain.
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McInnes J, Wierda K, Snellinx A, Bounti L, Wang YC, Stancu IC, Apóstolo N, Gevaert K, Dewachter I, Spires-Jones TL, De Strooper B, De Wit J, Zhou L, Verstreken P. Synaptogyrin-3 Mediates Presynaptic Dysfunction Induced by Tau. Neuron 2018; 97:823-835.e8. [DOI: 10.1016/j.neuron.2018.01.022] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 11/25/2022]
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14
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Waberer L, Henrich E, Peetz O, Morgner N, Dötsch V, Bernhard F, Volknandt W. The synaptic vesicle protein SV31 assembles into a dimer and transports Zn 2. J Neurochem 2016; 140:280-293. [PMID: 27917477 DOI: 10.1111/jnc.13886] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/25/2016] [Accepted: 10/29/2016] [Indexed: 01/20/2023]
Abstract
The integral synaptic vesicle protein SV31 has been shown to bind divalent cations. Here, we demonstrate that SV31 protein synthesized within a cell-free system binds Zn2+ and to a lower extent Ni2+ and Cu2+ ions. Expression with Zn2+ stabilized the protein and increased solubility. SV31 was preferentially monomeric in detergent and revealed specific binding of Zn2+ . When co-translationally inserted into defined nanodisc bilayers, SV31 assembled into dimeric complexes, resulting in increased binding of Zn2+ . Putative Zn2+ -binding motifs within SV31 comprise aspartic acid and histidine residues. Site-directed mutagenesis of two conserved aspartic acid residues leads to a potent decrease in Zn2+ binding but did not affect dimerization. Chemical modification of histidine residues abolished some of the Zn2+ -binding capacity. We demonstrate proton-dependent transport of Zn2+ as by accumulation of fluorescent FluoZin-1 inside of SV31-containing proteoliposomes. Transport activity has a Km value of 44.3 μM and required external Zn2+ and internal acidic pH. Our results demonstrate that the synaptic vesicle-integral protein SV31 functions as a proton-dependent Zn2+ transporter. SV31 may attribute specific and yet undiscovered functions to subsets of synapses.
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Affiliation(s)
- Lisa Waberer
- Institute of Cell Biology and Neuroscience, Goethe-University, Frankfurt am Main, Germany
| | - Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Oliver Peetz
- Institute of Physical and Theoretical Chemistry, Goethe-University, Frankfurt am Main, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute of Cell Biology and Neuroscience, Goethe-University, Frankfurt am Main, Germany
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15
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Effective Mechanism for Synthesis of Neurotransmitter Glutamate and its Loading into Synaptic Vesicles. Neurochem Res 2016; 42:64-76. [DOI: 10.1007/s11064-016-2037-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 08/14/2016] [Accepted: 08/17/2016] [Indexed: 01/14/2023]
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16
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17
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TUSC5 regulates insulin-mediated adipose tissue glucose uptake by modulation of GLUT4 recycling. Mol Metab 2015; 4:795-810. [PMID: 26629404 PMCID: PMC4632119 DOI: 10.1016/j.molmet.2015.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 08/11/2015] [Accepted: 08/18/2015] [Indexed: 12/26/2022] Open
Abstract
Objective Failure to properly dispose of glucose in response to insulin is a serious health problem, occurring during obesity and is associated with type 2 diabetes development. Insulin-stimulated glucose uptake is facilitated by the translocation and plasma membrane fusion of vesicles containing glucose transporter 4 (GLUT4), the rate-limiting step of post-prandial glucose disposal. Methods We analyzed the role of Tusc5 in the regulation of insulin-stimulated Glut4-mediated glucose uptake in vitro and in vivo. Furthermore, we measured Tusc5 expression in two patient cohorts. Results Herein, we report that TUSC5 controls insulin-stimulated glucose uptake in adipocytes, in vitro and in vivo. TUSC5 facilitates the proper recycling of GLUT4 and other key trafficking proteins during prolonged insulin stimulation, thereby enabling proper protein localization and complete vesicle formation, processes that ultimately enable insulin-stimulated glucose uptake. Tusc5 knockout mice exhibit impaired glucose disposal and TUSC5 expression is predictive of glucose tolerance in obese individuals, independent of body weight. Furthermore, we show that TUSC5 is a PPARγ target and in its absence the anti-diabetic effects of TZDs are significantly blunted. Conclusions Collectively, these findings establish TUSC5 as an adipose tissue-specific protein that enables proper protein recycling, linking the ubiquitous vesicle traffic machinery with tissue-specific insulin-mediated glucose uptake into adipose tissue and the maintenance of a healthy metabolic phenotype in mice and humans. Tusc5 regulates glucose uptake in adipose tissue by modulating the GSV recycling machinery. Tusc5 knockout mice develop insulin resistance due to impaired adipose tissue glucose uptake. Rosiglitazone improves glucose homeostasis in part through the induction of Tusc5. Tusc5 is a novel adipose specific adaptor protein linking Glut4 trafficking to the ubiquitous machinery.
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18
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High-Throughput All-Optical Analysis of Synaptic Transmission and Synaptic Vesicle Recycling in Caenorhabditis elegans. PLoS One 2015; 10:e0135584. [PMID: 26312752 PMCID: PMC4552474 DOI: 10.1371/journal.pone.0135584] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 07/24/2015] [Indexed: 12/13/2022] Open
Abstract
Synaptic vesicles (SVs) undergo a cycle of biogenesis and membrane fusion to release transmitter, followed by recycling. How exocytosis and endocytosis are coupled is intensively investigated. We describe an all-optical method for identification of neurotransmission genes that can directly distinguish SV recycling factors in C. elegans, by motoneuron photostimulation and muscular RCaMP Ca2+ imaging. We verified our approach on mutants affecting synaptic transmission. Mutation of genes affecting SV recycling (unc-26 synaptojanin, unc-41 stonin, unc-57 endophilin, itsn-1 intersectin, snt-1 synaptotagmin) showed a distinct ‘signature’ of muscle Ca2+ dynamics, induced by cholinergic motoneuron photostimulation, i.e. faster rise, and earlier decrease of the signal, reflecting increased synaptic fatigue during ongoing photostimulation. To facilitate high throughput, we measured (3–5 times) ~1000 nematodes for each gene. We explored if this method enables RNAi screening for SV recycling genes. Previous screens for synaptic function genes, based on behavioral or pharmacological assays, allowed no distinction of the stage of the SV cycle in which a protein might act. We generated a strain enabling RNAi specifically only in cholinergic neurons, thus resulting in healthier animals and avoiding lethal phenotypes resulting from knockdown elsewhere. RNAi of control genes resulted in Ca2+ measurements that were consistent with results obtained in the respective genomic mutants, albeit to a weaker extent in most cases, and could further be confirmed by opto-electrophysiological measurements for mutants of some of the genes, including synaptojanin. We screened 95 genes that were previously implicated in cholinergic transmission, and several controls. We identified genes that clustered together with known SV recycling genes, exhibiting a similar signature of their Ca2+ dynamics. Five of these genes (C27B7.7, erp-1, inx-8, inx-10, spp-10) were further assessed in respective genomic mutants; however, while all showed electrophysiological phenotypes indicative of reduced cholinergic transmission, no obvious SV recycling phenotypes could be uncovered for these genes.
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19
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Hackett JT, Ueda T. Glutamate Release. Neurochem Res 2015; 40:2443-60. [PMID: 26012367 DOI: 10.1007/s11064-015-1622-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 05/17/2015] [Accepted: 05/20/2015] [Indexed: 12/18/2022]
Abstract
Our aim was to review the processes of glutamate release from both biochemical and neurophysiological points of view. A large body of evidence now indicates that glutamate is specifically accumulated into synaptic vesicles, which provides strong support for the concept that glutamate is released from synaptic vesicles and is the major excitatory neurotransmitter. Evidence suggests the notion that synaptic vesicles, in order to sustain the neurotransmitter pool of glutamate, are endowed with an efficient mechanism for vesicular filling of glutamate. Glutamate-loaded vesicles undergo removal of Synapsin I by CaM kinase II-mediated phosphorylation, transforming to the release-ready pool. Vesicle docking to and fusion with the presynaptic plasma membrane are thought to be mediated by the SNARE complex. The Ca(2+)-dependent step in exocytosis is proposed to be mediated by synaptotagmin.
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Affiliation(s)
- John T Hackett
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22908-0736, USA
| | - Tetsufumi Ueda
- Molecular and Behavioral Neuroscience Institute, The University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA. .,Department of Pharmacology, Medical School, The University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Psychiatry, Medical School, The University of Michigan, Ann Arbor, MI, 48109, USA.
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20
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Narayanan M, Leung SA, Inaba Y, Elguindy MM, Nakamaru-Ogiso E. Semiquinone intermediates are involved in the energy coupling mechanism of E. coli complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:681-9. [PMID: 25868873 DOI: 10.1016/j.bbabio.2015.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 03/14/2015] [Accepted: 04/05/2015] [Indexed: 11/28/2022]
Abstract
Complex I (NADH:quinone oxidoreductase) is central to cellular aerobic energy metabolism, and its deficiency is involved in many human mitochondrial diseases. Complex I translocates protons across the membrane using electron transfer energy. Semiquinone (SQ) intermediates appearing during catalysis are suggested to be key for the coupling mechanism in complex I. However, the existence of SQ has remained controversial due to the extreme difficulty in detecting unstable and low intensity SQ signals. Here, for the first time with Escherichia coli complex I reconstituted in proteoliposomes, we successfully resolved and characterized three distinct SQ species by EPR. These species include: fast-relaxing SQ (SQNf) with P1/2 (half-saturation power level)>50mW and a wider linewidth (12.8 G); slow-relaxing SQ (SQNs) with P1/2=2-3mW and a 10G linewidth; and very slow-relaxing SQ (SQNvs) with P1/2= ~0.1mW and a 7.5G linewidth. The SQNf signals completely disappeared in the presence of the uncoupler gramicidin D or squamotacin, a potent E. coli complex I inhibitor. The pH dependency of the SQNf signals correlated with the proton-pumping activities of complex I. The SQNs signals were insensitive to gramicidin D, but sensitive to squamotacin. The SQNvs signals were insensitive to both gramicidin D and squamotacin. Our deuterium exchange experiments suggested that SQNf is neutral, while SQNs and SQNvs are anion radicals. The SQNs signals were lost in the ΔNuoL mutant missing transporter module subunits NuoL and NuoM. The roles and relationships of the SQ intermediates in the coupling mechanism are discussed.
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Affiliation(s)
- Madhavan Narayanan
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Steven A Leung
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Yuta Inaba
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Mahmoud M Elguindy
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Eiko Nakamaru-Ogiso
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
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21
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Hasan F, Vidanapathirana P, Das S, Fernand VE, Siraj N, Losso JN, Warner IM. Ionic liquids as buffer additives in ionic liquid-polyacrylamide gel electrophoresis separation of mixtures of low and high molecular weight proteins. RSC Adv 2015. [DOI: 10.1039/c5ra11559k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Three novel ionic liquids (ILs) [CnPBr] (n= 4, 6, 8) have been synthesized and were used as buffer additives in IL-PAGE separation of mixture of acidic proteins.
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Affiliation(s)
- Farhana Hasan
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
| | | | - Susmita Das
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
| | - Vivian E. Fernand
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
- Department of Chemistry and Physics
| | - Noureen Siraj
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
| | - Jack N. Losso
- Department of Food Science
- Louisiana State University
- Baton Rouge
- USA
| | - Isiah M. Warner
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
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22
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Ramirez DMO, Kavalali ET. The role of non-canonical SNAREs in synaptic vesicle recycling. CELLULAR LOGISTICS 2014; 2:20-27. [PMID: 22645707 PMCID: PMC3355972 DOI: 10.4161/cl.20114] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An increasing number of studies suggest that distinct pools of synaptic vesicles drive specific forms of neurotransmission. Interspersed with these functional studies are analyses of the synaptic vesicle proteome which have consistently detected the presence of so-called “non-canonical” SNAREs that typically function in fusion and trafficking of other subcellular structures within the neuron. The recent identification of certain non-canonical vesicular SNAREs driving spontaneous (e.g., VAMP7 and vti1a) or evoked asynchronous (e.g., VAMP4) release integrates and corroborates existing data from functional and proteomic studies and implies that at least some complement of non-canonical SNAREs resident on synaptic vesicles function in neurotransmission. Here, we discuss the specific roles in neurotransmission of proteins homologous to each member of the classical neuronal SNARE complex consisting of synaptobrevin2, syntaxin-1 and SNAP-25.
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α-Synuclein assembles into higher-order multimers upon membrane binding to promote SNARE complex formation. Proc Natl Acad Sci U S A 2014; 111:E4274-83. [PMID: 25246573 DOI: 10.1073/pnas.1416598111] [Citation(s) in RCA: 341] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Physiologically, α-synuclein chaperones soluble NSF attachment protein receptor (SNARE) complex assembly and may also perform other functions; pathologically, in contrast, α-synuclein misfolds into neurotoxic aggregates that mediate neurodegeneration and propagate between neurons. In neurons, α-synuclein exists in an equilibrium between cytosolic and membrane-bound states. Cytosolic α-synuclein appears to be natively unfolded, whereas membrane-bound α-synuclein adopts an α-helical conformation. Although the majority of studies showed that cytosolic α-synuclein is monomeric, it is unknown whether membrane-bound α-synuclein is also monomeric, and whether chaperoning of SNARE complex assembly by α-synuclein involves its cytosolic or membrane-bound state. Here, we show using chemical cross-linking and fluorescence resonance energy transfer (FRET) that α-synuclein multimerizes into large homomeric complexes upon membrane binding. The FRET experiments indicated that the multimers of membrane-bound α-synuclein exhibit defined intermolecular contacts, suggesting an ordered array. Moreover, we demonstrate that α-synuclein promotes SNARE complex assembly at the presynaptic plasma membrane in its multimeric membrane-bound state, but not in its monomeric cytosolic state. Our data delineate a folding pathway for α-synuclein that ranges from a monomeric, natively unfolded form in cytosol to a physiologically functional, multimeric form upon membrane binding, and show that only the latter but not the former acts as a SNARE complex chaperone at the presynaptic terminal, and may protect against neurodegeneration.
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24
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Laßek M, Weingarten J, Volknandt W. The synaptic proteome. Cell Tissue Res 2014; 359:255-65. [PMID: 25038742 DOI: 10.1007/s00441-014-1943-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/04/2014] [Indexed: 11/29/2022]
Abstract
Synapses are focal hot spots for signal transduction and plasticity in the brain. A synapse comprises an axon terminus, the presynapse, the synaptic cleft containing extracellular matrix proteins as well as adhesion molecules, and the postsynaptic density as target structure for chemical signaling. The proteomes of the presynaptic and postsynaptic active zones control neurotransmitter release and perception. These tasks demand short- and long-term structural and functional dynamics of the synapse mediated by its proteinaceous inventory. This review addresses subcellular fractionation protocols and the related proteomic approaches to the various synaptic subcompartments with an emphasis on the presynaptic active zone (PAZ). Furthermore, it discusses major constituents of the PAZ including the amyloid precursor protein family members. Numerous proteins regulating the rearrangement of the cytoskeleton are indicative of the functional and structural dynamics of the pre- and postsynapse. The identification of protein candidates of the synapse provides the basis for further analyzing the interaction of synaptic proteins with their targets, and the effect of their deletion opens novel insights into the functional role of these proteins in neuronal communication. The knowledge of the molecular interactome is also a prerequisite for understanding numerous neurodegenerative diseases.
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Affiliation(s)
- Melanie Laßek
- Molecular and Cellular Neurobiology, Goethe University, Frankfurt, Germany
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25
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Laßek M, Weingarten J, Volknandt W. The Proteome of the Murine Presynaptic Active Zone. Proteomes 2014; 2:243-257. [PMID: 28250380 PMCID: PMC5302740 DOI: 10.3390/proteomes2020243] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/09/2014] [Accepted: 04/21/2014] [Indexed: 01/09/2023] Open
Abstract
The proteome of the presynaptic active zone controls neurotransmitter release and the short- and long-term structural and functional dynamics of the nerve terminal. The proteinaceous inventory of the presynaptic active zone has recently been reported. This review will evaluate the subcellular fractionation protocols and the proteomic approaches employed. A breakthrough for the identification of the proteome of the presynaptic active zone was the successful employment of antibodies directed against a cytosolic epitope of membrane integral synaptic vesicle proteins for the immunopurification of synaptic vesicles docked to the presynaptic plasma membrane. Combining immunopurification and subsequent analytical mass spectrometry, hundreds of proteins, including synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular and extracellular signaling and a large variety of adhesion molecules, were identified. Numerous proteins regulating the rearrangement of the cytoskeleton are indicative of the functional and structural dynamics of the presynapse. This review will critically discuss both the experimental approaches and prominent protein candidates identified. Many proteins have not previously been assigned to the presynaptic release sites and may be directly involved in the short- and long-term structural modulation of the presynaptic compartment. The identification of proteinaceous constituents of the presynaptic active zone provides the basis for further analyzing the interaction of presynaptic proteins with their targets and opens novel insights into the functional role of these proteins in neuronal communication.
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Affiliation(s)
- Melanie Laßek
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
| | - Jens Weingarten
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Department Molecular and Cellular Neurobiology, Max von Laue Str. 13, 60438 Frankfurt am Main, Germany.
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26
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Weingarten J, Lassek M, Mueller BF, Rohmer M, Lunger I, Baeumlisberger D, Dudek S, Gogesch P, Karas M, Volknandt W. The proteome of the presynaptic active zone from mouse brain. Mol Cell Neurosci 2014; 59:106-18. [PMID: 24534009 DOI: 10.1016/j.mcn.2014.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 01/07/2023] Open
Abstract
Neurotransmitter release as well as the structural and functional dynamics of the presynaptic active zone is controlled by proteinaceous components. Here we describe for the first time an experimental approach for the isolation of the presynaptic active zone from individual mouse brains, a prerequisite for understanding the functional inventory of the presynaptic protein network and for the later analysis of changes occurring in mutant mice. Using a monoclonal antibody against the ubiquitous synaptic vesicle protein SV2 we immunopurified synaptic vesicles docked to the presynaptic plasma membrane. Enrichment studies by means of Western blot analysis and mass spectrometry identified 485 proteins belonging to an impressive variety of functional categories. Our data suggest that presynaptic active zones represent focal hot spots that are not only involved in the regulation of neurotransmitter release but also in multiple structural and functional alterations the adult nerve terminal undergoes during neural activity in adult CNS. They furthermore open new avenues for characterizing alterations in the active zone proteome of mutant mice and their corresponding controls, including the various mouse models of neurological diseases.
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Affiliation(s)
- Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Melanie Lassek
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Benjamin F Mueller
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Marion Rohmer
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Ilaria Lunger
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | | | - Simone Dudek
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Patricia Gogesch
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany
| | - Michael Karas
- Institute of Pharmaceutical Chemistry, Cluster of Excellence "Macromolecular Complexes", Goethe-University, Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum, Goethe-University, Frankfurt am Main, Germany.
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27
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Li KW, Jimenez CR. Synapse proteomics: current status and quantitative applications. Expert Rev Proteomics 2014; 5:353-60. [DOI: 10.1586/14789450.5.2.353] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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28
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Barth J, Volknandt W. Proteomic investigations of the synaptic vesicle interactome. Expert Rev Proteomics 2014; 8:211-20. [DOI: 10.1586/epr.11.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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29
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Tribl F, Meyer HE, Marcus K. Analysis of organelles within the nervous system: impact on brain and organelle functions. Expert Rev Proteomics 2014; 5:333-51. [DOI: 10.1586/14789450.5.2.333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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30
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Kong HK, Wong MH, Chan HM, Lo SCL. Chronic exposure of adult rats to low doses of methylmercury induced a state of metabolic deficit in the somatosensory cortex. J Proteome Res 2013; 12:5233-45. [PMID: 23984759 DOI: 10.1021/pr400356v] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Because of the ever-increasing bioaccumulation of methylmercury (MeHg) in the marine food chain, human consumers are exposed to low doses of MeHg continually through seafood consumption. Epidemiological studies strongly suggest that chronic prenatal exposure to nanomolar of MeHg has immense negative impacts on neurological development in neonates. However, effects of chronic exposure to low doses (CELDs) of MeHg in adult brains on a molecular level are unknown. The current study aims to investigate the molecular effects of CELD of MeHg on adult somatosensory cortex in a rat model using proteomic techniques. Young adult rats were fed with a low dose of MeHg (40 μg/kg body weight/day) for a maximum of 12 weeks. Whole proteome expression of the somatosensory cortex (S1 area) of normal rats and those with CELD to MeHg were compared. Levels of MeHg, total calcium, adenosine triphosphate (ATP), and pyruvate were also measured. Comparative proteomic studies of the somatosensory cortexes revealed that 94 proteins involved in the various metabolic processes (including carbohydrate metabolism, generation of precursors for essential metabolites, energy, proteins, cellular components for morphogenesis, and neurotransmission) were down-regulated. Consequently, levels of important end products of active metabolism including ATP, pyruvate, and total calcium were also found to be significantly reduced concomitantly. Our results showed that CELD of MeHg induced a state of metabolic deficit in the somatosensory cortex of adult rats.
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Affiliation(s)
- Hang-Kin Kong
- Food Safety and Technology Research Centre, The Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University , Room Y810, Lee Shau Kee Building (Block Y), Hung Hom, Hong Kong, China
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Yao J, de la Iglesia HO, Bajjalieh SM. Loss of the SV2-like protein SVOP produces no apparent deficits in laboratory mice. PLoS One 2013; 8:e68215. [PMID: 23894296 PMCID: PMC3722232 DOI: 10.1371/journal.pone.0068215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/28/2013] [Indexed: 11/18/2022] Open
Abstract
Neurons express two families of transporter-like proteins − Synaptic Vesicle protein 2 (SV2A, B, and C) and SV2-related proteins (SVOP and SVOPL). Both families share structural similarity with the Major Facilitator (MF) family of transporters. SV2 is present in all neurons and endocrine cells, consistent with it playing a key role in regulated exocytosis. Like SV2, SVOP is expressed in all brain regions, with highest levels in cerebellum, hindbrain and pineal gland. Furthermore, SVOP is expressed earlier in development than SV2 and is one of the neuronal proteins whose expression declines most during aging. Although SV2 is essential for survival, it is not required for development. Because significant levels of neurotransmission remain in the absence of SV2 it has been proposed that SVOP performs a function similar to that of SV2 that mitigates the phenotype of SV2 knockout mice. To test this, we generated SVOP knockout mice and SVOP/SV2A/SV2B triple knockout mice. Mice lacking SVOP are viable, fertile and phenotypically normal. Measures of neurotransmission and behaviors dependent on the cerebellum and pineal gland revealed no measurable phenotype. SVOP/SV2A/SV2B triple knockout mice did not display a phenotype more severe than mice harboring the SV2A/SV2B gene deletions. These findings support the interpretation that SVOP performs a unique, though subtle, function that is not necessary for survival under normal conditions.
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Affiliation(s)
- Jia Yao
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | | | - Sandra M. Bajjalieh
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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32
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Laßek M, Weingarten J, Einsfelder U, Brendel P, Müller U, Volknandt W. Amyloid precursor proteins are constituents of the presynaptic active zone. J Neurochem 2013; 127:48-56. [PMID: 23815291 DOI: 10.1111/jnc.12358] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/21/2013] [Accepted: 06/26/2013] [Indexed: 11/27/2022]
Abstract
The amyloid precursor protein (APP) and its mammalian homologs, APLP1, APLP2, have been allocated to an organellar pool residing in the Golgi apparatus and in endosomal compartments, and in its mature form to a cell surface-localized pool. In the brain, all APPs are restricted to neurons; however, their precise localization at the plasma membrane remained enigmatic. Employing a variety of subcellular fractionation steps, we isolated two synaptic vesicle (SV) pools from rat and mouse brain, a pool consisting of synaptic vesicles only and a pool comprising SV docked to the presynaptic plasma membrane. Immunopurification of these two pools using a monoclonal antibody directed against the 12 membrane span synaptic vesicle protein2 (SV2) demonstrated unambiguously that APP, APLP1 and APLP2 are constituents of the active zone of murine brain but essentially absent from free synaptic vesicles. The specificity of immunodetection was confirmed by analyzing the respective knock-out animals. The fractionation experiments further revealed that APP is accumulated in the fraction containing docked synaptic vesicles. These data present novel insights into the subsynaptic localization of APPs and are a prerequisite for unraveling the physiological role of all mature APP proteins in synaptic physiology.
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Affiliation(s)
- Melanie Laßek
- Department of Molecular and Cellular Neurobiology, Goethe-University, Frankfurt am Main, Germany
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33
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Abstract
The defining motor characteristics of Parkinson's disease (PD) are mediated by the neurotransmitter dopamine (DA). Dopamine molecules spend most of their lifespan stored in intracellular vesicles awaiting release and very little time in the extracellular space or the cytosol. Without proper packaging of transmitter and trafficking of vesicles to the active zone, dopamine neurotransmission cannot occur. In the cytosol, dopamine is readily oxidized; excessive cytosolic dopamine oxidation may be pathogenic to nigral neurons in PD. Thus, factors that disrupt vesicular function may impair signaling and increase the vulnerability of dopamine neurons. This review outlines the many mechanisms by which disruption of vesicular function may contribute to the pathogenesis of PD. From direct inhibition of dopamine transport into vesicles by pharmacological or toxicological agents to alterations in vesicle trafficking by PD-related gene products, variations in the proper compartmentalization of dopamine can wreak havoc on a functional dopamine pathway. Findings from patient populations, imaging studies, transgenic models, and mechanistic studies will be presented to document the relationship between impaired vesicular function and vulnerability of the nigrostriatal dopamine system. Given the deleterious effects of impaired vesicular function, strategies aimed at enhancing vesicular function may be beneficial in the treatment of PD.
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Affiliation(s)
- Shawn P. Alter
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Gina M. Lenzi
- Department of Biochemistry, School of Medicine, Emory University, Atlanta, GA, USA
| | - Alison I. Bernstein
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Gary W. Miller
- Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA. Department of Pharmacology, School of Medicine, Emory University, Atlanta, GA, USA. Department of Environmental Health, Rollins School of Public Health, Claudia Nance Rollins Bldg, Room 8007, 1518 Clifton Road, NE, Atlanta, GA 30322, USA
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34
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Boyken J, Grønborg M, Riedel D, Urlaub H, Jahn R, Chua JJE. Molecular profiling of synaptic vesicle docking sites reveals novel proteins but few differences between glutamatergic and GABAergic synapses. Neuron 2013; 78:285-97. [PMID: 23622064 DOI: 10.1016/j.neuron.2013.02.027] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2013] [Indexed: 11/30/2022]
Abstract
Neurotransmission involves calcium-triggered fusion of docked synaptic vesicles at specialized presynaptic release sites. While many of the participating proteins have been identified, the molecular composition of these sites has not been characterized comprehensively. Here, we report a procedure to biochemically isolate fractions highly enriched in docked synaptic vesicles. The fraction is largely free of postsynaptic proteins and most other organelles while containing most known synaptic vesicle and active zone proteins. Numerous presynaptic transmembrane proteins were also identified, together with over 30 uncharacterized proteins, many of which are evolutionarily conserved. Quantitative proteomic comparison of glutamate- and GABA-specific docking complexes revealed that, except of neurotransmitter-specific enzymes and transporters, only few proteins were selectively enriched in either fraction. We conclude that the core machinery involved in vesicle docking and exocytosis does not show compositional differences between the two types of synapses.
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Affiliation(s)
- Janina Boyken
- Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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35
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Nelson JC, Stavoe AKH, Colón-Ramos DA. The actin cytoskeleton in presynaptic assembly. Cell Adh Migr 2013; 7:379-87. [PMID: 23628914 DOI: 10.4161/cam.24803] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dramatic morphogenetic processes underpin nearly every step of nervous system development, from initial neuronal migration and axon guidance to synaptogenesis. Underlying this morphogenesis are dynamic rearrangements of cytoskeletal architecture. Here we discuss the roles of the actin cytoskeleton in the development of presynaptic terminals, from the elaboration of terminal arbors to the recruitment of presynaptic vesicles and active zone components. The studies discussed here underscore the importance of actin regulation at every step in neuronal circuit assembly.
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Affiliation(s)
- Jessica C Nelson
- Program in Cellular Neuroscience, Neurodegeneration and Repair; Department of Cell Biology; Yale University; New Haven, CT USA
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36
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Shi N, Tian C, Liang X, Jiang P, Liang L, Zhou L, Shu Y, Chen P, Wang Y. Proteome analysis of actin filament-associated proteins in the postnatal rat cerebellum. Neuroscience 2012; 227:90-101. [DOI: 10.1016/j.neuroscience.2012.09.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/21/2012] [Accepted: 09/22/2012] [Indexed: 10/27/2022]
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37
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Heo S, Csaszar E, Jung G, Beuk T, Höger H, Lubec G. Hippocampal levels and activity of the sodium/potassium transporting ATPase subunit α-3 (AT1A3) are paralleling memory training in the multiple T-maze in the C57BL/6J mouse. Neurochem Int 2012; 61:702-12. [PMID: 22797008 DOI: 10.1016/j.neuint.2012.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 07/03/2012] [Accepted: 07/04/2012] [Indexed: 12/23/2022]
Abstract
Although the sodium/potassium transporting ATPase subunit alpha-3 (AT1A3) has been linked to memory mechanisms in rodents, regulation of this ATPase in terms of activity and complex levels by memory performance in a land maze has not been shown so far. It was therefore the aim of the study to link memory retrieval in the multiple T-Maze (MTM) to AT1A3 protein levels and activity. C57BL/6J mice were trained in the MTM and euthanized 6h following memory retrieval. Hippocampal membrane proteins were prepared by ultracentrifugation and run on blue native gel electrophoresis (BN-PAGE). Enzyme activity was evaluated using an in-gel method. AT1A3 protein was characterized using mass spectrometry (nano-LC-ESI-MS/MS). On BN-PAGE a single band was observed at 240 kDa, which corresponds to the dimeric form of the enzyme. Higher levels of AT1A3 complex were seen in trained mice. Also ATPase activity was higher in trained mice, and was observed both at 110 and at 240 kDa. Mass spectrometry unambiguously identified AT1A3 with 98.91% sequence coverage. A series of novel AT1A3 phosphorylation sites were detected. Taken together, it was shown that increased AT1A3 protein levels for the dimer as well as AT1A3 activity represented by the monomer and the dimer were paralleling memory training in the MTM. This may be relevant for understanding the role of the catalytic hydrolysis of ATP coupled with the exchange of sodium and potassium ions across the plasma membrane that generates the electrochemical gradient of sodium and potassium ions. Herein, we provide evidence for a possible role of AT1A3 in memory mechanisms and support previous findings using different animal models for memory formation.
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Affiliation(s)
- Seok Heo
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria
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38
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Sann SB, Crane MM, Lu H, Jin Y. Rabx-5 regulates RAB-5 early endosomal compartments and synaptic vesicles in C. elegans. PLoS One 2012; 7:e37930. [PMID: 22675499 PMCID: PMC3366993 DOI: 10.1371/journal.pone.0037930] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 04/30/2012] [Indexed: 01/25/2023] Open
Abstract
Early endosomal membrane compartments are required for the formation and recycling of synaptic vesicles, but how these compartments are regulated is incompletely understood. We performed a forward genetic screen in C. elegans for mutations that affect RAB-5 labeled early endosomal compartments in GABAergic motoneurons. Here we report the isolation and characterization of one mutation, rabx-5. The rabx-5 mutation leads to decreased intensity of YFP::RAB-5 in the cell soma but increased intensity in the synaptic and intersynaptic regions of the axon. This effect is due to the bias of the cycling state of RAB-5, and results from a change in the organization of the early endosomal compartment as well as the membrane binding state of RAB-5. Synaptic vesicle accumulation is altered in rabx-5 mutants, and synaptic transmission from cholinergic neurons is decreased. Early endosomal membrane compartments show disorganization with ageing and rabx-5 mutant animals age faster. These results suggest that rabx-5 regulation of RAB-5 compartments is important for maintaining proper synaptic function throughout the lifetime.
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Affiliation(s)
- Sharon B. Sann
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (SS); (YJ)
| | - Matthew M. Crane
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Hang Lu
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
- Howard Hughes Medical Institute University of California San Diego, La Jolla, California, United States of America
- * E-mail: (SS); (YJ)
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39
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Sigismund S, Confalonieri S, Ciliberto A, Polo S, Scita G, Di Fiore PP. Endocytosis and signaling: cell logistics shape the eukaryotic cell plan. Physiol Rev 2012; 92:273-366. [PMID: 22298658 DOI: 10.1152/physrev.00005.2011] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of endocytosis has evolved remarkably in little more than a decade. This is the result not only of advances in our knowledge of its molecular and biological workings, but also of a true paradigm shift in our understanding of what really constitutes endocytosis and of its role in homeostasis. Although endocytosis was initially discovered and studied as a relatively simple process to transport molecules across the plasma membrane, it was subsequently found to be inextricably linked with almost all aspects of cellular signaling. This led to the notion that endocytosis is actually the master organizer of cellular signaling, providing the cell with understandable messages that have been resolved in space and time. In essence, endocytosis provides the communications and supply routes (the logistics) of the cell. Although this may seem revolutionary, it is still likely to be only a small part of the entire story. A wealth of new evidence is uncovering the surprisingly pervasive nature of endocytosis in essentially all aspects of cellular regulation. In addition, many newly discovered functions of endocytic proteins are not immediately interpretable within the classical view of endocytosis. A possible framework, to rationalize all this new knowledge, requires us to "upgrade" our vision of endocytosis. By combining the analysis of biochemical, biological, and evolutionary evidence, we propose herein that endocytosis constitutes one of the major enabling conditions that in the history of life permitted the development of a higher level of organization, leading to the actuation of the eukaryotic cell plan.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
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40
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Takeda K, Ishida A, Takahashi K, Ueda T. Synaptic vesicles are capable of synthesizing the VGLUT substrate glutamate from α-ketoglutarate for vesicular loading. J Neurochem 2012; 121:184-96. [PMID: 22309504 DOI: 10.1111/j.1471-4159.2012.07684.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Synaptic vesicle loading of glutamate is a pivotal step in glutamate synaptic transmission. The molecular machinery responsible for this step is comprised of v-type proton-pump ATPase and a vesicular glutamate transporter. Recent evidence indicates that synaptic vesicles are endowed with glycolytic ATP-synthesizing enzymes, providing energy for immediate use by vesicle-bound proton-pump ATPase. In this study, we provide evidence that synaptic vesicles are also capable of synthesizing the vesicular glutamate transporter substrate glutamate, from α-ketoglutarate and l-aspartate (as the amino group donor); glutamate thus produced is taken up into vesicles. We also report a finding that α-ketoglutarate-derived glutamate uptake into synaptic vesicles and aspartate aminotransferase are inhibited by 2,3-pyrazinedicarboxylate. Evidence is given that this is a selective inhibitor for aspartate aminotransferase. These observations provide insight into understanding the nerve endings' mechanism for high efficiency in glutamate transmission. Finding this inhibitor may have implications for further experimentation on the role of α-ketoglutarate-derived glutamate in glutamate transmission.
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Affiliation(s)
- Kouji Takeda
- Molecular & Behavioral Neuroscience Institute, Medical School, The University of Michigan, Ann Arbor, Michigan, USA
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41
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Volknandt W, Karas M. Proteomic analysis of the presynaptic active zone. Exp Brain Res 2012; 217:449-61. [DOI: 10.1007/s00221-012-3031-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 02/04/2012] [Indexed: 02/06/2023]
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42
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Zhang T, Gai Q, Qu F, Zhang Y. Ionic liquid-assisted SDS-PAGE to improve human serum protein separation. Electrophoresis 2011; 32:2904-10. [DOI: 10.1002/elps.201100184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/14/2011] [Accepted: 05/16/2011] [Indexed: 12/23/2022]
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43
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Co-expression studies of the orphan carrier protein Slc10a4 and the vesicular carriers VAChT and VMAT2 in the rat central and peripheral nervous system. Neuroscience 2011; 193:109-21. [DOI: 10.1016/j.neuroscience.2011.06.068] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 06/22/2011] [Accepted: 06/24/2011] [Indexed: 11/22/2022]
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44
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Expression, phosphorylation, and glycosylation of CNS proteins in aversive operant conditioning associated memory in Lymnaea stagnalis. Neuroscience 2011; 186:94-109. [DOI: 10.1016/j.neuroscience.2011.04.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 04/08/2011] [Accepted: 04/09/2011] [Indexed: 11/18/2022]
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45
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Two-dimensional gel electrophoresis in proteomics: a tutorial. J Proteomics 2011; 74:1829-41. [PMID: 21669304 DOI: 10.1016/j.jprot.2011.05.040] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/23/2011] [Accepted: 05/26/2011] [Indexed: 12/12/2022]
Abstract
Two-dimensional electrophoresis of proteins has preceded, and accompanied, the birth of proteomics. Although it is no longer the only experimental scheme used in modern proteomics, it still has distinct features and advantages. The purpose of this tutorial paper is to guide the reader through the history of the field, then through the main steps of the process, from sample preparation to in-gel detection of proteins, commenting the constraints and caveats of the technique. Then the limitations and positive features of two-dimensional electrophoresis are discussed (e.g. its unique ability to separate complete proteins and its easy interfacing with immunoblotting techniques), so that the optimal type of applications of this technique in current and future proteomics can be perceived. This is illustrated by a detailed example taken from the literature and commented in detail. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 2).
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46
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Colucci-D'Amato L, Farina A, Vissers JPC, Chambery A. Quantitative neuroproteomics: classical and novel tools for studying neural differentiation and function. Stem Cell Rev Rep 2011; 7:77-93. [PMID: 20352529 DOI: 10.1007/s12015-010-9136-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mechanisms underlying neural stem cell proliferation, differentiation and maturation play a critical role in the formation and wiring of neuronal connections. This process involves the activation of multiple serial events, which guide the undifferentiated cells to different lineages via distinctive developmental programs, forming neuronal circuits and thus shaping the adult nervous system. Furthermore, alterations within these strictly regulated pathways can lead to severe neurological and psychiatric diseases. In this framework, the investigation of the high dynamic protein expression changes and other factors affecting protein functions, for example post-translational modifications, the alterations of protein interaction networks, is of pivotal importance for the understanding of the molecular mechanisms responsible for cell differentiation. More recently, proteomic studies in neuroscience ("neuroproteomics") are receiving increased interest for the primary understanding of the regulatory networks underlying neuronal differentiation processes. Besides the classical two-dimensional-based proteomic strategies, the emerging platforms for LC-MS shotgun proteomic analysis hold great promise in unraveling the molecular basis of neural stem cell differentiation. In this review, recent advancements in label-free LC-MS quantitative neuroproteomics are highlighted as a new tool for the study of neural differentiation and functions, in comparison to mass spectrometry-based labeling approaches. The more commonly used protein profiling strategies and model systems for the analysis of neural differentiation are also discussed, along with the challenging proteomic approaches aimed to analyze the nervous system-specific organelles, the neural cells secretome and the specific protein interaction networks.
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Affiliation(s)
- Luca Colucci-D'Amato
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
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47
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Groemer TW, Thiel CS, Holt M, Riedel D, Hua Y, Hüve J, Wilhelm BG, Klingauf J. Amyloid precursor protein is trafficked and secreted via synaptic vesicles. PLoS One 2011; 6:e18754. [PMID: 21556148 PMCID: PMC3083403 DOI: 10.1371/journal.pone.0018754] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 03/16/2011] [Indexed: 02/04/2023] Open
Abstract
A large body of evidence has implicated amyloid precursor protein (APP) and its proteolytic derivatives as key players in the physiological context of neuronal synaptogenesis and synapse maintenance, as well as in the pathology of Alzheimer's Disease (AD). Although APP processing and release are known to occur in response to neuronal stimulation, the exact mechanism by which APP reaches the neuronal surface is unclear. We now demonstrate that a small but relevant number of synaptic vesicles contain APP, which can be released during neuronal activity, and most likely represent the major exocytic pathway of APP. This novel finding leads us to propose a revised model of presynaptic APP trafficking that reconciles existing knowledge on APP with our present understanding of vesicular release and recycling.
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Affiliation(s)
- Teja W. Groemer
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Department of Psychiatry and Psychotherapy, University of Erlangen,
Erlangen, Germany
| | - Cora S. Thiel
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
| | - Matthew Holt
- Department of Neurobiology, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- * E-mail: (MH); (JK)
| | - Dietmar Riedel
- Electron Microscopy Group, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
| | - Yunfeng Hua
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
| | - Jana Hüve
- Fluorescence Microscopy Facility Münster, Institute of Medical
Physics and Biophysics, University of Münster, Münster,
Germany
| | - Benjamin G. Wilhelm
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
| | - Jürgen Klingauf
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
- * E-mail: (MH); (JK)
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48
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Protein quantification at the single vesicle level reveals that a subset of synaptic vesicle proteins are trafficked with high precision. J Neurosci 2011; 31:1461-70. [PMID: 21273430 DOI: 10.1523/jneurosci.3805-10.2011] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Protein sorting represents a potential point of regulation in neurotransmission because it dictates the protein composition of synaptic vesicles, the organelle that mediates transmitter release. Although the average number of most vesicle proteins has been estimated using bulk biochemical approaches (Takamori et al., 2006), no information exists on the intervesicle variability of protein number, and thus on the precision with which proteins are sorted to vesicles. To address this, we adapted a single molecule quantification approach (Mutch et al., 2007) and used it to quantify both the average number and variance of seven integral membrane proteins in brain synaptic vesicles. We report that four vesicle proteins, SV2, the proton ATPase, Vglut1, and synaptotagmin 1, showed little intervesicle variation in number, indicating they are sorted to vesicles with high precision. In contrast, the apparent number of VAMP2/synaptobrevin 2, synaptophysin, and synaptogyrin demonstrated significant intervesicle variability. These findings place constraints on models of protein function at the synapse and raise the possibility that changes in vesicle protein expression affect vesicle composition and functioning.
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49
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Li Y, Massey K, Witkiewicz H, Schnitzer JE. Systems analysis of endothelial cell plasma membrane proteome of rat lung microvasculature. Proteome Sci 2011; 9:15. [PMID: 21447187 PMCID: PMC3080792 DOI: 10.1186/1477-5956-9-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 03/29/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Endothelial cells line all blood vessels to form the blood-tissue interface which is critical for maintaining organ homeostasis and facilitates molecular exchange. We recently used tissue subcellular fractionation combined with several multi-dimensional mass spectrometry-based techniques to enhance identification of lipid-embedded proteins for large-scale proteomic mapping of luminal endothelial cell plasma membranes isolated directly from rat lungs in vivo. The biological processes and functions of the proteins expressed at this important blood-tissue interface remain unexplored at a large scale. RESULTS We performed an unbiased systems analysis of the endothelial cell surface proteome containing over 1800 proteins to unravel the major functions and pathways apparent at this interface. As expected, many key functions of plasma membranes in general (i.e., cell surface signaling pathways, cytoskeletal organization, adhesion, membrane trafficking, metabolism, mechanotransduction, membrane fusion, and vesicle-mediated transport) and endothelial cells in particular (i.e., blood vessel development and maturation, angiogenesis, regulation of endothelial cell proliferation, protease activity, and endocytosis) were significantly overrepresented in this proteome. We found that endothelial cells express multiple proteins that mediate processes previously reported to be restricted to neuronal cells, such as neuronal survival and plasticity, axon growth and regeneration, synaptic vesicle trafficking and neurotransmitter metabolic process. Surprisingly, molecular machinery for protein synthesis was also detected as overrepresented, suggesting that endothelial cells, like neurons, can synthesize proteins locally at the cell surface. CONCLUSION Our unbiased systems analysis has led to the potential discovery of unexpected functions in normal endothelium. The discovery of the existence of protein synthesis at the plasma membrane in endothelial cells provides new insight into the blood-tissue interface and endothelial cell surface biology.
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Affiliation(s)
- Yan Li
- Proteogenomics Research Institute for Systems Medicine, 11107 Roselle Street, San Diego, California 92121, USA.
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Vertommen A, Panis B, Swennen R, Carpentier SC. Challenges and solutions for the identification of membrane proteins in non-model plants. J Proteomics 2011; 74:1165-81. [PMID: 21354347 DOI: 10.1016/j.jprot.2011.02.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/04/2011] [Accepted: 02/16/2011] [Indexed: 01/27/2023]
Abstract
The workhorse for proteomics in non-model plants is classical two-dimensional electrophoresis, a combination of iso-electric focusing and SDS-PAGE. However, membrane proteins with multiple membrane spanning domains are hardly detected on classical 2-DE gels because of their low abundance and poor solubility in aqueous media. In the current review, solutions that have been proposed to handle these two problems in non-model plants are discussed. An overview of alternative techniques developed for membrane proteomics is provided together with a comparison of their strong and weak points. Subsequently, strengths and weaknesses of the different techniques and methods to evaluate the identification of membrane proteins are discussed. Finally, an overview of recent plant membrane proteome studies is provided with the used separation technique and the number of identified membrane proteins listed.
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Affiliation(s)
- A Vertommen
- Laboratory of Tropical Crop Improvement, Department of Biosystems, K.U. Leuven, Kasteelpark Arenberg 13, B-3001 Heverlee, Belgium
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