1
|
Gundersen CB. Cysteine string proteins. Prog Neurobiol 2020; 188:101758. [DOI: 10.1016/j.pneurobio.2020.101758] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 12/17/2022]
|
2
|
Anderson EN, Hirpa D, Zheng KH, Banerjee R, Gunawardena S. The Non-amyloidal Component Region of α-Synuclein Is Important for α-Synuclein Transport Within Axons. Front Cell Neurosci 2020; 13:540. [PMID: 32038170 PMCID: PMC6984405 DOI: 10.3389/fncel.2019.00540] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/21/2019] [Indexed: 11/13/2022] Open
Abstract
Proper transport of the Parkinson's disease (PD) protein, α-synuclein (α-syn), is thought to be crucial for its localization and function at the synapse. Previous work has shown that defects in long distance transport within narrow caliber axons occur early in PD, but how such defects contribute to PD is unknown. Here we test the hypothesis that the NAC region is involved in facilitating proper transport of α-syn within axons via its association with membranes. Excess α-syn or fPD mutant α-synA53T accumulates within larval axons perturbing the transport of synaptic proteins. These α-syn expressing larvae also show synaptic morphological and larval locomotion defects, which correlate with the extent of α-syn-mediated axonal accumulations. Strikingly, deletion of the NAC region (α-synΔ71-82) prevented α-syn accumulations and axonal blockages, and reduced its synaptic localization due to decreased axonal entry and axonal transport of α-syn, due to less α-syn bound to membranes. Intriguingly, co-expression α-synΔ71-82 with full-length α-syn rescued α-syn accumulations and synaptic morphological defects, and decreased the ratio of the insoluble higher molecular weight (HMW)/soluble low molecular weight (LMW) α-syn, indicating that this region is perhaps important for the dimerization of α-syn on membranes. Together, our observations suggest that under physiological conditions, α-syn associates with membranes via the NAC region, and that too much α-syn perturbs axonal transport via aggregate formation, instigating synaptic and behavioral defects seen in PD.
Collapse
Affiliation(s)
| | | | | | | | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, United States
| |
Collapse
|
3
|
Imler E, Pyon JS, Kindelay S, Torvund M, Zhang YQ, Chandra SS, Zinsmaier KE. A Drosophila model of neuronal ceroid lipofuscinosis CLN4 reveals a hypermorphic gain of function mechanism. eLife 2019; 8:e46607. [PMID: 31663851 PMCID: PMC6897512 DOI: 10.7554/elife.46607] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/29/2019] [Indexed: 12/24/2022] Open
Abstract
The autosomal dominant neuronal ceroid lipofuscinoses (NCL) CLN4 is caused by mutations in the synaptic vesicle (SV) protein CSPα. We developed animal models of CLN4 by expressing CLN4 mutant human CSPα (hCSPα) in Drosophila neurons. Similar to patients, CLN4 mutations induced excessive oligomerization of hCSPα and premature lethality in a dose-dependent manner. Instead of being localized to SVs, most CLN4 mutant hCSPα accumulated abnormally, and co-localized with ubiquitinated proteins and the prelysosomal markers HRS and LAMP1. Ultrastructural examination revealed frequent abnormal membrane structures in axons and neuronal somata. The lethality, oligomerization and prelysosomal accumulation induced by CLN4 mutations was attenuated by reducing endogenous wild type (WT) dCSP levels and enhanced by increasing WT levels. Furthermore, reducing the gene dosage of Hsc70 also attenuated CLN4 phenotypes. Taken together, we suggest that CLN4 alleles resemble dominant hypermorphic gain of function mutations that drive excessive oligomerization and impair membrane trafficking.
Collapse
Affiliation(s)
- Elliot Imler
- Graduate Interdisciplinary Program in NeuroscienceUniversity of ArizonaTucsonUnited States
- Department of NeuroscienceUniversity of ArizonaTucsonUnited States
| | - Jin Sang Pyon
- Department of NeuroscienceUniversity of ArizonaTucsonUnited States
- Undergraduate Program in Neuroscience and Cognitive Science, Department of Molecular and Cellular BiologyUniversity of ArizonaTucsonUnited States
| | - Selina Kindelay
- Department of NeuroscienceUniversity of ArizonaTucsonUnited States
- Undergraduate Program in Neuroscience and Cognitive Science, Department of Molecular and Cellular BiologyUniversity of ArizonaTucsonUnited States
| | - Meaghan Torvund
- Graduate Interdisciplinary Program in NeuroscienceUniversity of ArizonaTucsonUnited States
- Department of NeuroscienceUniversity of ArizonaTucsonUnited States
| | - Yong-quan Zhang
- Department of NeuroscienceYale UniversityNew HavenUnited States
- Department of NeurologyYale UniversityNew HavenUnited States
| | - Sreeganga S Chandra
- Department of NeuroscienceYale UniversityNew HavenUnited States
- Department of NeurologyYale UniversityNew HavenUnited States
| | - Konrad E Zinsmaier
- Department of NeuroscienceUniversity of ArizonaTucsonUnited States
- Department of Molecular and Cellular BiologyUniversity of ArizonaTucsonUnited States
| |
Collapse
|
4
|
Lopez-Ortega E, Ruiz R, Tabares L. CSPα, a Molecular Co-chaperone Essential for Short and Long-Term Synaptic Maintenance. Front Neurosci 2017; 11:39. [PMID: 28239331 PMCID: PMC5301022 DOI: 10.3389/fnins.2017.00039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 01/19/2017] [Indexed: 01/26/2023] Open
Abstract
Cysteine string protein α (CSPα) is a vesicle protein located in the presynaptic terminal of most synapses. CSPα is an essential molecular co-chaperone that facilitates the correct folding of proteins and the assembly of the exocytic machinery. The absence of this protein leads to altered neurotransmitter release and neurodegeneration in multiple model systems, from flies to mice. In humans, CSPα mutations are associated with the development of neuronal ceroid lipofuscinosis (NCL), a neurodegenerative disease characterized by intracellular accumulation of lysosomal material. Here, we review the physiological role of CSPα and the pathology resulting from the homozygous deletion of the gene or its mutations. In addition, we investigate whether long-term moderate reduction of the protein produces motor dysfunction. We found that 1-year-old CSPα heterozygous mice display a reduced ability to sustain motor unit recruitment during repetitive stimulation, which indicates that physiological levels of CSPα are required for normal neuromuscular responses in mice and, likely, in humans.
Collapse
Affiliation(s)
- Elena Lopez-Ortega
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville Seville, Spain
| | - Rocío Ruiz
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Seville Seville, Spain
| | - Lucia Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville Seville, Spain
| |
Collapse
|
5
|
Patel P, Prescott GR, Burgoyne RD, Lian LY, Morgan A. Phosphorylation of Cysteine String Protein Triggers a Major Conformational Switch. Structure 2016; 24:1380-1386. [PMID: 27452402 PMCID: PMC4975591 DOI: 10.1016/j.str.2016.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/17/2016] [Accepted: 06/02/2016] [Indexed: 12/11/2022]
Abstract
Cysteine string protein (CSP) is a member of the DnaJ/Hsp40 chaperone family that localizes to neuronal synaptic vesicles. Impaired CSP function leads to neurodegeneration in humans and model organisms as a result of misfolding of client proteins involved in neurotransmission. Mammalian CSP is phosphorylated in vivo on Ser10, and this modulates its protein interactions and effects on neurotransmitter release. However, there are no data on the structural consequences of CSP phosphorylation to explain these functional effects. We show that Ser10 phosphorylation causes an order-to-disorder transition that disrupts CSP's extreme N-terminal α helix. This triggers the concomitant formation of a hairpin loop stabilized by ionic interactions between phosphoSer10 and the highly conserved J-domain residue, Lys58. These phosphorylation-induced effects result in significant changes to CSP conformation and surface charge distribution. The phospho-switch revealed here provides structural insight into how Ser10 phosphorylation modulates CSP function and also has potential implications for other DnaJ phosphoproteins. First structure of a phosphorylated DnaJ/Hsp40 protein Phosphorylation destabilizes CSP's N-terminal α helix Newly disordered, phosphorylated N-terminal loop binds to the J domain Phosphorylation causes significant changes to CSP conformation and surface charge
Collapse
Affiliation(s)
- Pryank Patel
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK; NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK; Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Gerald R Prescott
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - Lu-Yun Lian
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
| | - Alan Morgan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
| |
Collapse
|
6
|
Kleber J, Chen YC, Michels B, Saumweber T, Schleyer M, Kähne T, Buchner E, Gerber B. Synapsin is required to "boost" memory strength for highly salient events. ACTA ACUST UNITED AC 2015; 23:9-20. [PMID: 26670182 PMCID: PMC4749839 DOI: 10.1101/lm.039685.115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/28/2015] [Indexed: 12/11/2022]
Abstract
Synapsin is an evolutionarily conserved presynaptic phosphoprotein. It is encoded by only one gene in the Drosophila genome and is expressed throughout the nervous system. It regulates the balance between reserve and releasable vesicles, is required to maintain transmission upon heavy demand, and is essential for proper memory function at the behavioral level. Task-relevant sensorimotor functions, however, remain intact in the absence of Synapsin. Using an odor–sugar reward associative learning paradigm in larval Drosophila, we show that memory scores in mutants lacking Synapsin (syn97) are lower than in wild-type animals only when more salient, higher concentrations of odor or of the sugar reward are used. Furthermore, we show that Synapsin is selectively required for larval short-term memory. Thus, without Synapsin Drosophila larvae can learn and remember, but Synapsin is required to form memories that match in strength to event salience—in particular to a high saliency of odors, of rewards, or the salient recency of an event. We further show that the residual memory scores upon a lack of Synapsin are not further decreased by an additional lack of the Sap47 protein. In combination with mass spectrometry data showing an up-regulated phosphorylation of Synapsin in the larval nervous system upon a lack of Sap47, this is suggestive of a functional interdependence of Synapsin and Sap47.
Collapse
Affiliation(s)
- Jörg Kleber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Yi-Chun Chen
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Birgit Michels
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Timo Saumweber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Thilo Kähne
- Otto von Guericke Universität Magdeburg, Institut für Experimentelle Innere Medizin, 39120 Magdeburg, Germany
| | - Erich Buchner
- Institut für Klinische Neurobiologie, 97078 Würzburg, Germany
| | - Bertram Gerber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany Otto von Guericke Universität Magdeburg, Institut für Biologie, 39106 Magdeburg, Germany
| |
Collapse
|
7
|
Lemonidis K, Sanchez-Perez MC, Chamberlain LH. Identification of a Novel Sequence Motif Recognized by the Ankyrin Repeat Domain of zDHHC17/13 S-Acyltransferases. J Biol Chem 2015; 290:21939-50. [PMID: 26198635 PMCID: PMC4571948 DOI: 10.1074/jbc.m115.657668] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/20/2015] [Indexed: 11/06/2022] Open
Abstract
S-Acylation is a major post-translational modification affecting several cellular processes. It is particularly important for neuronal functions. This modification is catalyzed by a family of transmembrane S-acyltransferases that contain a conserved zinc finger DHHC (zDHHC) domain. Typically, eukaryote genomes encode for 7-24 distinct zDHHC enzymes, with two members also harboring an ankyrin repeat (AR) domain at their cytosolic N termini. The AR domain of zDHHC enzymes is predicted to engage in numerous interactions and facilitates both substrate recruitment and S-acylation-independent functions; however, the sequence/structural features recognized by this module remain unknown. The two mammalian AR-containing S-acyltransferases are the Golgi-localized zDHHC17 and zDHHC13, also known as Huntingtin-interacting proteins 14 and 14-like, respectively; they are highly expressed in brain, and their loss in mice leads to neuropathological deficits that are reminiscent of Huntington's disease. Here, we report that zDHHC17 and zDHHC13 recognize, via their AR domain, evolutionary conserved and closely related sequences of a [VIAP][VIT]XXQP consensus in SNAP25, SNAP23, cysteine string protein, Huntingtin, cytoplasmic linker protein 3, and microtubule-associated protein 6. This novel AR-binding sequence motif is found in regions predicted to be unstructured and is present in a number of zDHHC17 substrates and zDHHC17/13-interacting S-acylated proteins. This is the first study to identify a motif recognized by AR-containing zDHHCs.
Collapse
Affiliation(s)
- Kimon Lemonidis
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, Univesity of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - Maria C Sanchez-Perez
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, Univesity of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - Luke H Chamberlain
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, Univesity of Strathclyde, Glasgow G4 0RE, United Kingdom
| |
Collapse
|
8
|
Abstract
Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: "negative" memories for stimuli preceding them and "positive" memories for stimuli experienced at the moment of "relief." Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training ("forward conditioning" of the odor), whereas after shock-odor training ("backward conditioning" of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences.
Collapse
|
9
|
Donnelier J, Braun JEA. CSPα-chaperoning presynaptic proteins. Front Cell Neurosci 2014; 8:116. [PMID: 24808827 PMCID: PMC4010753 DOI: 10.3389/fncel.2014.00116] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 04/09/2014] [Indexed: 12/11/2022] Open
Abstract
Synaptic transmission relies on precisely regulated and exceedingly fast protein-protein interactions that involve voltage-gated channels, the exocytosis/endocytosis machinery as well as signaling pathways. Although we have gained an ever more detailed picture of synaptic architecture much remains to be learned about how synapses are maintained. Synaptic chaperones are “folding catalysts” that preserve proteostasis by regulating protein conformation (and therefore protein function) and prevent unwanted protein-protein interactions. Failure to maintain synapses is an early hallmark of several degenerative diseases. Cysteine string protein (CSPα) is a presynaptic vesicle protein and molecular chaperone that has a central role in preventing synaptic loss and neurodegeneration. Over the past few years, a number of different “client proteins” have been implicated as CSPα substrates including voltage-dependent ion channels, signaling proteins and proteins critical to the synaptic vesicle cycle. Here we review the ion channels and synaptic protein complexes under the influence of CSPα and discuss gaps in our current knowledge.
Collapse
Affiliation(s)
- Julien Donnelier
- Department of Physiology and Pharmacology, The Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary Calgary, AB, Canada
| | - Janice E A Braun
- Department of Physiology and Pharmacology, The Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary Calgary, AB, Canada
| |
Collapse
|
10
|
Abstract
The synapse-associated protein of 47 kDa (SAP47) is a member of a phylogenetically conserved gene family of hitherto unknown function. In Drosophila, SAP47 is encoded by a single gene (Sap47) and is expressed throughout all synaptic regions of the wild-type larval brain; specifically, electron microscopy reveals anti-SAP47 immunogold labeling within 30 nm of presynaptic vesicles. To analyze SAP47 function, we used the viable and fertile deletion mutant Sap47(156), which suffers from a 1.7 kb deletion in the regulatory region and the first exon. SAP47 cannot be detected by either immunoblotting or immunohistochemistry in Sap47(156) mutants. These mutants exhibit normal sensory detection of odorants and tastants as well as normal motor performance and basic neurotransmission at the neuromuscular junction. However, short-term plasticity at this synapse is distorted. Interestingly, Sap47(156) mutant larvae also show a 50% reduction in odorant-tastant associative learning ability; a similar associative impairment is observed in a second deletion allele (Sap47(201)) and upon reduction of SAP47 levels using RNA interference. In turn, transgenically restoring SAP47 in Sap47(156) mutant larvae rescues the defect in associative function. This report thus is the first to suggest a function for SAP47. It specifically argues that SAP47 is required for proper behavioral and synaptic plasticity in flies-and prompts the question whether its homologs are required for proper behavioral and synaptic plasticity in other species as well.
Collapse
|
11
|
Michels B, Chen YC, Saumweber T, Mishra D, Tanimoto H, Schmid B, Engmann O, Gerber B. Cellular site and molecular mode of synapsin action in associative learning. Learn Mem 2011; 18:332-44. [PMID: 21518740 DOI: 10.1101/lm.2101411] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Synapsin is an evolutionarily conserved, presynaptic vesicular phosphoprotein. Here, we ask where and how synapsin functions in associative behavioral plasticity. Upon loss or reduction of synapsin in a deletion mutant or via RNAi, respectively, Drosophila larvae are impaired in odor-sugar associative learning. Acute global expression of synapsin and local expression in only the mushroom body, a third-order "cortical" brain region, fully restores associative ability in the mutant. No rescue is found by synapsin expression in mushroom body input neurons or by expression excluding the mushroom bodies. On the molecular level, we find that a transgenically expressed synapsin with dysfunctional PKA-consensus sites cannot rescue the defect of the mutant in associative function, thus assigning synapsin as a behaviorally relevant effector of the AC-cAMP-PKA cascade. We therefore suggest that synapsin acts in associative memory trace formation in the mushroom bodies, as a downstream element of AC-cAMP-PKA signaling. These analyses provide a comprehensive chain of explanation from the molecular level to an associative behavioral change.
Collapse
Affiliation(s)
- Birgit Michels
- Universität Würzburg, Biozentrum, Neurobiologie und Genetik, 97074 Würzburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Johnson JN, Ahrendt E, Braun JEA. CSPalpha: the neuroprotective J protein. Biochem Cell Biol 2010; 88:157-65. [PMID: 20453918 DOI: 10.1139/o09-124] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cysteine string protein (CSPalpha, also called DnaJC5) is unique among J proteins. Similar to other J proteins, CSPalpha interacts with and activates the ATPase of Hsc70s (heat shock proteins of 70 kDa), thereby harnessing the ATPase activity for conformational work on client proteins. In contrast to other J proteins, CSPalpha is anchored to synaptic vesicles, as well as to exocrine, endocrine and neuroendocrine secretory granules, and has been shown to have an essential anti-neurodegenerative role. CSPalpha-null organisms exhibit progressive neurodegeneration, behavioural deficits, and premature death, most likely due to the progressive misfolding of one or more client proteins. Here we highlight recent advances in our understanding of the critical role that CSPalpha plays in governing exocytotic secretory functions.
Collapse
Affiliation(s)
- Jadah N Johnson
- Department of Physiology and Pharmacology and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | | | | |
Collapse
|
13
|
Xu F, Proft J, Gibbs S, Winkfein B, Johnson JN, Syed N, Braun JEA. Quercetin targets cysteine string protein (CSPalpha) and impairs synaptic transmission. PLoS One 2010; 5:e11045. [PMID: 20548785 PMCID: PMC2883571 DOI: 10.1371/journal.pone.0011045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 05/21/2010] [Indexed: 01/25/2023] Open
Abstract
Background Cysteine string protein (CSPα) is a synaptic vesicle protein that displays unique anti-neurodegenerative properties. CSPα is a member of the conserved J protein family, also called the Hsp40 (heat shock protein of 40 kDa) protein family, whose importance in protein folding has been recognized for many years. Deletion of the CSPα in mice results in knockout mice that are normal for the first 2–3 weeks of life followed by an unexplained presynaptic neurodegeneration and premature death. How CSPα prevents neurodegeneration is currently not known. As a neuroprotective synaptic vesicle protein, CSPα represents a promising therapeutic target for the prevention of neurodegenerative disorders. Methodology/Principal Findings Here, we demonstrate that the flavonoid quercetin promotes formation of stable CSPα-CSPα dimers and that quercetin-induced dimerization is dependent on the unique cysteine string region. Furthermore, in primary cultures of Lymnaea neurons, quercetin induction of CSPα dimers correlates with an inhibition of synapse formation and synaptic transmission suggesting that quercetin interfers with CSPα function. Quercetin's action on CSPα is concentration dependent and does not promote dimerization of other synaptic proteins or other J protein family members and reduces the assembly of CSPα:Hsc70 units (70kDa heat shock cognate protein). Conclusions/Significance Quercetin is a plant derived flavonoid and popular nutritional supplement proposed to prevent memory loss and altitude sickness among other ailments, although its precise mechanism(s) of action has been unclear. In view of the therapeutic promise of upregulation of CSPα and the undesired consequences of CSPα dysfunction, our data establish an essential proof of principle that pharmaceutical agents can selectively target the neuroprotective J protein CSPα.
Collapse
Affiliation(s)
- Fenglian Xu
- Department of Anatomy and Cell Biology, University of Calgary, Calgary, Alberta, Canada
| | - Juliane Proft
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Sarah Gibbs
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Bob Winkfein
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Jadah N. Johnson
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Naweed Syed
- Department of Anatomy and Cell Biology, University of Calgary, Calgary, Alberta, Canada
| | - Janice E. A. Braun
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
| |
Collapse
|
14
|
A semi-correlative technique for the subcellular localization of proteins in Drosophila synapses. J Neurosci Methods 2010; 185:273-9. [DOI: 10.1016/j.jneumeth.2009.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 09/29/2009] [Accepted: 10/11/2009] [Indexed: 11/21/2022]
|
15
|
Prescott GR, Gorleku OA, Greaves J, Chamberlain LH. Palmitoylation of the synaptic vesicle fusion machinery. J Neurochem 2009; 110:1135-49. [PMID: 19508429 DOI: 10.1111/j.1471-4159.2009.06205.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fusion of synaptic vesicles with the pre-synaptic plasma membrane mediates the secretion of neurotransmitters at nerve terminals. This pathway is regulated by an array of protein-protein interactions. Of central importance are the soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein receptor (SNARE) proteins syntaxin 1 and SNAP25, which are associated with the pre-synaptic plasma membrane and vesicle-associated membrane protein (VAMP2), a synaptic vesicle SNARE. Syntaxin 1, SNAP25 and VAMP2 interact to form a tight complex bridging the vesicle and plasma membranes, which has been suggested to represent the minimal membrane fusion machinery. Synaptic vesicle fusion is stimulated by a rise in intraterminal Ca2+ levels, and a major Ca2+ sensor for vesicle fusion is synaptotagmin I. Synaptotagmin is likely to couple Ca2+ entry to vesicle fusion via Ca2+-dependent and independent interactions with membrane phospholipids and the SNARE proteins. Intriguingly, syntaxin 1, SNAP25, VAMP2 and synaptotagmin I have all been reported to be modified by palmitoylation in neurons. In this review, we discuss the mechanisms and dynamics of palmitoylation of these proteins and speculate on how palmitoylation might contribute to the regulation of synaptic vesicle fusion.
Collapse
Affiliation(s)
- Gerald R Prescott
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | |
Collapse
|
16
|
Hofbauer A, Ebel T, Waltenspiel B, Oswald P, Chen YC, Halder P, Biskup S, Lewandrowski U, Winkler C, Sickmann A, Buchner S, Buchner E. The Wuerzburg hybridoma library against Drosophila brain. J Neurogenet 2009; 23:78-91. [PMID: 19132598 DOI: 10.1080/01677060802471627] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This review describes the present state of a project to identify and characterize novel nervous system proteins by using monoclonal antibodies (mAbs) against the Drosophila brain. Some 1,000 hybridoma clones were generated by injection of homogenized Drosophila brains or heads into mice and fusion of their spleen cells with myeloma cells. Testing the mAbs secreted by these clones identified a library of about 200 mAbs, which selectively stain specific structures of the Drosophila brain. Using the approach "from antibody to gene", several genes coding for novel proteins of the presynaptic terminal were cloned and characterized. These include the "cysteine string protein" gene (Csp, mAb ab49), the "synapse-associated protein of 47 kDa" gene (Sap47, mAbs nc46 and nb200), and the "Bruchpilot" gene (brp, mAb nc82). By a "candidate" approach, mAb nb33 was shown to recognize the pigment dispersing factor precursor protein. mAbs 3C11 and pok13 were raised against bacterially expressed Drosophila synapsin and calbindin-32, respectively, after the corresponding cDNAs had been isolated from an expression library by using antisera against mammalian proteins. Recently, it was shown that mAb aa2 binds the Drosophila homolog of "epidermal growth factor receptor pathway substrate clone 15" (Eps15). Identification of the targets of mAbs na21, ab52, and nb181 is presently attempted. Here, we review the available information on the function of these proteins and present staining patterns in the Drosophila brain for classes of mAbs that either bind differentially in the eye, in neuropil, in the cell-body layer, or in small subsets of neurons. The prospects of identifying the corresponding antigens by various approaches, including protein purification and mass spectrometry, are discussed.
Collapse
Affiliation(s)
- Alois Hofbauer
- Institut für Zoologie, Lehrstuhl für Entwicklungsbiologie, Regensburg, Germany.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Ohyama T, Verstreken P, Ly CV, Rosenmund T, Rajan A, Tien AC, Haueter C, Schulze KL, Bellen HJ. Huntingtin-interacting protein 14, a palmitoyl transferase required for exocytosis and targeting of CSP to synaptic vesicles. J Cell Biol 2007; 179:1481-96. [PMID: 18158335 PMCID: PMC2373489 DOI: 10.1083/jcb.200710061] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 11/14/2007] [Indexed: 02/08/2023] Open
Abstract
Posttranslational modification through palmitoylation regulates protein localization and function. In this study, we identify a role for the Drosophila melanogaster palmitoyl transferase Huntingtin-interacting protein 14 (HIP14) in neurotransmitter release. hip14 mutants show exocytic defects at low frequency stimulation and a nearly complete loss of synaptic transmission at higher temperature. Interestingly, two exocytic components known to be palmitoylated, cysteine string protein (CSP) and SNAP25, are severely mislocalized at hip14 mutant synapses. Complementary DNA rescue and localization experiments indicate that HIP14 is required solely in the nervous system and is essential for presynaptic function. Biochemical studies indicate that HIP14 palmitoylates CSP and that CSP is not palmitoylated in hip14 mutants. Furthermore, the hip14 exocytic defects can be suppressed by targeting CSP to synaptic vesicles using a chimeric protein approach. Our data indicate that HIP14 controls neurotransmitter release by regulating the trafficking of CSP to synapses.
Collapse
Affiliation(s)
- Tomoko Ohyama
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Dawson-Scully K, Lin Y, Imad M, Zhang J, Marin L, Horne JA, Meinertzhagen IA, Karunanithi S, Zinsmaier KE, Atwood HL. Morphological and functional effects of altered cysteine string protein at the Drosophila larval neuromuscular junction. Synapse 2007; 61:1-16. [PMID: 17068777 DOI: 10.1002/syn.20335] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The synaptic vesicle-associated cysteine string protein (CSP) is critical for neurotransmitter release at the neuromuscular junction (NMJ) of Drosophila, where the approximately 4% of mutant flies lacking CSP that survive to adulthood exhibit spastic jumping and shaking, temperature-sensitive paralysis, and premature death. Previously, it has been shown that CSP is also required for nerve terminal growth and the prevention of neurodegeneration in Drosophila and mice. At larval csp null mutant NMJs of Drosophila, intracellular recordings from the muscle showed that evoked release is significantly reduced at room temperature. However, it remained unclear whether the reduction in evoked release might be due to a loss of synaptic boutons, loss of synapses, and alterations in trafficking of vesicles to synapses. To resolve these issues, we have examined synaptic structure and function of csp null mutant NMJs at the level of single boutons. csp null mutations proportionally reduce the number of synaptic boutons of both motor neurons (1s and 1b) innervating larval muscles 6 and 7, while the number of synapses per bouton remains normal. However, focal recordings from individual synaptic boutons show that nerve-evoked neurotransmitter release is also impaired in both 1s and 1b boutons. Further, our ultrastructural analyses show that the reduction in evoked release at low stimulation frequencies is not due to a loss of synapses or to alterations in docked vesicles at synapses. Together, these data suggest that CSP promotes synaptic growth and evoked neurotransmitter release by mechanistically independent signaling pathways.
Collapse
Affiliation(s)
- Ken Dawson-Scully
- Department of Biology, University of Toronto, Mississauga, Ontario L5L 1C6, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Schwarz TL. Transmitter release at the neuromuscular junction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2006; 75:105-44. [PMID: 17137926 DOI: 10.1016/s0074-7742(06)75006-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Affiliation(s)
- Thomas L Schwarz
- Program in Neurobiology, Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| |
Collapse
|
20
|
Bronk P, Nie Z, Klose MK, Dawson-Scully K, Zhang J, Robertson RM, Atwood HL, Zinsmaier KE. The multiple functions of cysteine-string protein analyzed at Drosophila nerve terminals. J Neurosci 2006; 25:2204-14. [PMID: 15745946 PMCID: PMC6726096 DOI: 10.1523/jneurosci.3610-04.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The synaptic vesicle-associated cysteine-string protein (CSP) is important for synaptic transmission. Previous studies revealed multiple defects at neuromuscular junctions (NMJs) of csp null-mutant Drosophila, but whether these defects are independent of each other or mechanistically linked through J domain mediated-interactions with heat-shock cognate protein 70 (Hsc70) has not been established. To resolve this issue, we genetically dissected the individual functions of CSP by an in vivo structure/function analysis. Expression of mutant CSP lacking the J domain at csp null-mutant NMJs fully restored normal thermo-tolerance of evoked transmitter release but did not completely restore evoked release at room temperature and failed to reverse the abnormal intraterminal Ca2+ levels. This suggests that J domain-mediated functions are essential for the regulation of intraterminal Ca2+ levels but only partially required for regulating evoked release and not required for protecting evoked release against thermal stress. Hence, CSP can also act as an Hsc70-independent chaperone protecting evoked release from thermal stress. Expression of mutant CSP lacking the L domain restored neurotransmission and partially reversed the abnormal intraterminal Ca2+ levels, suggesting that the L domain is important, although not essential, for the role of CSP in regulating intraterminal Ca2+ levels. We detected no effects of csp mutations on individual presynaptic Ca2+ signals triggered by action potentials, suggesting that presynaptic Ca2+ entry is not primarily impaired. Both the J and L domains were also required for the role of CSP in synaptic growth. Together, these results suggest that CSP has several independent synaptic functions, affecting synaptic growth, evoked release, thermal protection of evoked release, and intraterminal Ca2+ levels at rest and during stimulation.
Collapse
Affiliation(s)
- Peter Bronk
- Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson, Arizona 85721-0077, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Smith GB, Umbach JA, Hirano A, Gundersen CB. Interaction between constitutively expressed heat shock protein, Hsc 70, and cysteine string protein is important for cortical granule exocytosis in Xenopus oocytes. J Biol Chem 2005; 280:32669-75. [PMID: 16055447 PMCID: PMC3846525 DOI: 10.1074/jbc.m501806200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In many species, binding of sperm to the egg initiates cortical granule exocytosis, an event that contributes to a sustained block of polyspermy. Interestingly, cortical granule exocytosis can be elicited in immature Xenopus oocytes by the protein kinase C activator, phorbol-12-myristate-13-acetate. In this study, we investigated the role of cysteine string protein (csp) in phorbol-12-myristate-13-acetate-evoked cortical granule exocytosis. Prior work indicated that csp is associated with cortical granules of Xenopus oocytes. In oocytes exhibiting >20-fold overexpression of full-length Xenopus csp, cortical granule exocytosis was reduced by approximately 80%. However, csp overexpression did not affect constitutive exocytosis. Subcellular fractionation and confocal fluorescence microscopy revealed that little or none of the overexpressed csp was associated with cortical granules. This accumulation of csp at sites other than cortical granules suggested that mislocalized csp might sequester a protein that is important for regulated exocytosis. Because the NH2-terminal region of csp includes a J-domain, which interacts with constitutively expressed 70-kDa heat shock proteins (Hsc 70), we evaluated the effect of overexpressing the J-domain of csp. Although the native J-domain of csp inhibited cortical granule exocytosis, point mutations that interfere with J-domain binding to Hsc 70 eliminated this inhibition. These data indicate that csp interaction with Hsc 70 molecular chaperones is vital for regulated secretion in Xenopus oocytes.
Collapse
Affiliation(s)
- Geoffrey B. Smith
- Department of Molecular and Medical Pharmacology, David P. Geffen UCLA School of Medicine, Los Angeles, California 90095
| | - Joy A. Umbach
- Department of Molecular and Medical Pharmacology, David P. Geffen UCLA School of Medicine, Los Angeles, California 90095
| | - Arlene Hirano
- Departments of Neurobiology and Medicine, David P. Geffen UCLA School of Medicine, Los Angeles, California 90095
| | - Cameron B. Gundersen
- Department of Molecular and Medical Pharmacology, David P. Geffen UCLA School of Medicine, Los Angeles, California 90095
- To whom correspondence should be addressed. Tel.: 310-825-3423; Fax: 310-206-8975;
| |
Collapse
|
22
|
Michels B, Diegelmann S, Tanimoto H, Schwenkert I, Buchner E, Gerber B. A role for Synapsin in associative learning: the Drosophila larva as a study case. Learn Mem 2005; 12:224-31. [PMID: 15930500 PMCID: PMC1142449 DOI: 10.1101/lm.92805] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 03/22/2005] [Indexed: 11/24/2022]
Abstract
Synapsins are evolutionarily conserved, highly abundant vesicular phosphoproteins in presynaptic terminals. They are thought to regulate the recruitment of synaptic vesicles from the reserve pool to the readily-releasable pool, in particular when vesicle release is to be maintained at high spiking rates. As regulation of transmitter release is a prerequisite for synaptic plasticity, we use the fruit fly Drosophila to ask whether Synapsin has a role in behavioral plasticity as well; in fruit flies, Synapsin is encoded by a single gene (syn). We tackled this question for associative olfactory learning in larval Drosophila by using the deletion mutant syn(97CS), which had been backcrossed to the Canton-S wild-type strain (CS) for 13 generations. We provide a molecular account of the genomic status of syn(97CS) by PCR and show the absence of gene product on Western blots and nerve-muscle preparations. We found that olfactory associative learning in syn(97CS) larvae is reduced to approximately 50% of wild-type CS levels; however, responsiveness to the to-be-associated stimuli and motor performance in untrained animals are normal. In addition, we introduce two novel behavioral control procedures to test stimulus responsiveness and motor performance after "sham training." Wild-type CS and syn(97CS) perform indistinguishably also in these tests. Thus, larval Drosophila can be used as a case study for a role of Synapsin in associative learning.
Collapse
Affiliation(s)
- Birgit Michels
- University of Würzburg, Biocenter, Am Hubland, Department of Genetics and Neurobiology, D 970 74 Würzburg, Germany
| | | | | | | | | | | |
Collapse
|
23
|
Boal F, Zhang H, Tessier C, Scotti P, Lang J. The variable C-terminus of cysteine string proteins modulates exocytosis and protein-protein interactions. Biochemistry 2005; 43:16212-23. [PMID: 15610015 DOI: 10.1021/bi048612+] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cysteine string proteins (Csps) are vesicle proteins involved in neurotransmission and hormone exocytosis. They are composed of distinct domains: a variable N-terminus, a J-domain followed by a linker region, a cysteine-rich string, and a C-terminus which diverges among isoforms. Their precise function and interactions are not fully understood. Using insulin exocytosis as a model, we show that the linker region and the C-terminus, but not the variable N-terminus, regulate overall secretion. Moreover, endogenous Csp1 binds in a calcium-dependent manner to monomeric VAMP2, and this interaction requires the C-terminus of Csp. The interaction is isoform specific as recombinant Csp1 binds VAMP1 and VAMP7, but not VAMP3. Cross-linking in permeabilized clonal beta-cells revealed homodimerization of Csp which is stimulated by Ca(2+) and again modulated by the variant C-terminus. Our data suggest that both interactions of Csp occur during exocytosis and may explain the effect of the variant C-terminus of this chaperon protein on peptide hormone secretion.
Collapse
Affiliation(s)
- Frédéric Boal
- Institut Européen de Chimie et Biologie, Pôle Biologie Cellulaire et Moléculaire, JE 2390, 33607 Pessac/Bordeaux, France
| | | | | | | | | |
Collapse
|
24
|
Phillips K. CYSTEINE STRING'S ESSENTIAL. J Exp Biol 2004. [DOI: 10.1242/jeb.00942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|