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Peñalva DA, Monnappa AK, Natale P, López-Montero I. Mfn2-dependent fusion pathway of PE-enriched micron-sized vesicles. Proc Natl Acad Sci U S A 2024; 121:e2313609121. [PMID: 39012824 PMCID: PMC11287154 DOI: 10.1073/pnas.2313609121] [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: 08/07/2023] [Accepted: 06/17/2024] [Indexed: 07/18/2024] Open
Abstract
Mitofusins (Mfn1 and Mfn2) are the mitochondrial outer-membrane fusion proteins in mammals and belong to the dynamin superfamily of multidomain GTPases. Recent structural studies of truncated variants lacking alpha helical transmembrane domains suggested that Mfns dimerize to promote the approximation and the fusion of the mitochondrial outer membranes upon the hydrolysis of guanine 5'-triphosphate disodium salt (GTP). However, next to the presence of GTP, the fusion activity seems to require multiple regulatory factors that control the dynamics and kinetics of mitochondrial fusion through the formation of Mfn1-Mfn2 heterodimers. Here, we purified and reconstituted the full-length murine Mfn2 protein into giant unilamellar vesicles (GUVs) with different lipid compositions. The incubation with GTP resulted in the fusion of Mfn2-GUVs. High-speed video-microscopy showed that the Mfn2-dependent membrane fusion pathway progressed through a zipper mechanism where the formation and growth of an adhesion patch eventually led to the formation of a membrane opening at the rim of the septum. The presence of physiological concentration (up to 30 mol%) of dioleoyl-phosphatidylethanolamine (DOPE) was shown to be a requisite to observe GTP-induced Mfn2-dependent fusion. Our observations show that Mfn2 alone can promote the fusion of micron-sized DOPE-enriched vesicles without the requirement of regulatory cofactors, such as membrane curvature, or the assistance of other proteins.
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Affiliation(s)
- Daniel A. Peñalva
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Sur, Bahía BlancaB8000, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía BlancaB8000, Argentina
| | - Ajay K. Monnappa
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
| | - Paolo Natale
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
- Departamento Química Física, Universidad Complutense de Madrid, Madrid28041, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid28041, Spain
| | - Iván López-Montero
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Madrid28041, Spain
- Departamento Química Física, Universidad Complutense de Madrid, Madrid28041, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid28041, Spain
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2
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Turrel O, Gao L, Sigrist SJ. Presynaptic regulators in memory formation. Learn Mem 2024; 31:a054013. [PMID: 38862173 PMCID: PMC11199941 DOI: 10.1101/lm.054013.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 04/17/2024] [Indexed: 06/13/2024]
Abstract
The intricate molecular and structural sequences guiding the formation and consolidation of memories within neuronal circuits remain largely elusive. In this study, we investigate the roles of two pivotal presynaptic regulators, the small GTPase Rab3, enriched at synaptic vesicles, and the cell adhesion protein Neurexin-1, in the formation of distinct memory phases within the Drosophila mushroom body Kenyon cells. Our findings suggest that both proteins play crucial roles in memory-supporting processes within the presynaptic terminal, operating within distinct plasticity modules. These modules likely encompass remodeling and maturation of existing active zones (AZs), as well as the formation of new AZs.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Lili Gao
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Cluster of Excellence NeuroCure, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
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3
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Salazar Lázaro A, Trimbuch T, Vardar G, Rosenmund C. The stability of the primed pool of synaptic vesicles and the clamping of spontaneous neurotransmitter release rely on the integrity of the C-terminal half of the SNARE domain of syntaxin-1A. eLife 2024; 12:RP90775. [PMID: 38512129 PMCID: PMC10957171 DOI: 10.7554/elife.90775] [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] [Indexed: 03/22/2024] Open
Abstract
The SNARE proteins are central in membrane fusion and, at the synapse, neurotransmitter release. However, their involvement in the dual regulation of the synchronous release while maintaining a pool of readily releasable vesicles remains unclear. Using a chimeric approach, we performed a systematic analysis of the SNARE domain of STX1A by exchanging the whole SNARE domain or its N- or C-terminus subdomains with those of STX2. We expressed these chimeric constructs in STX1-null hippocampal mouse neurons. Exchanging the C-terminal half of STX1's SNARE domain with that of STX2 resulted in a reduced RRP accompanied by an increased release rate, while inserting the C-terminal half of STX1's SNARE domain into STX2 leads to an enhanced priming and decreased release rate. Additionally, we found that the mechanisms for clamping spontaneous, but not for Ca2+-evoked release, are particularly susceptible to changes in specific residues on the outer surface of the C-terminus of the SNARE domain of STX1A. Particularly, mutations of D231 and R232 affected the fusogenicity of the vesicles. We propose that the C-terminal half of the SNARE domain of STX1A plays a crucial role in the stabilization of the RRP as well as in the clamping of spontaneous synaptic vesicle fusion through the regulation of the energetic landscape for fusion, while it also plays a covert role in the speed and efficacy of Ca2+-evoked release.
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Affiliation(s)
- Andrea Salazar Lázaro
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Thorsten Trimbuch
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Gülçin Vardar
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Christian Rosenmund
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
- NeuroCure Excellence ClusterBerlinGermany
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4
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Krok E, Franquelim HG, Chattopadhyay M, Orlikowska-Rzeznik H, Schwille P, Piatkowski L. Nanoscale structural response of biomimetic cell membranes to controlled dehydration. NANOSCALE 2023; 16:72-84. [PMID: 38062887 DOI: 10.1039/d3nr03078d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Although cell membranes exist in excess of water under physiological conditions, there are a number of biochemical processes, such as adsorption of biomacromolecules or membrane fusion events, that require partial or even complete transient dehydration of lipid membranes. Even though the dehydration process is crucial for understanding all fusion events, still little is known about the structural adaptation of lipid membranes when their interfacial hydration layer is perturbed. Here, we present the study of the nanoscale structural reorganization of phase-separated, supported lipid bilayers (SLBs) under a wide range of hydration conditions. Model lipid membranes were characterised using a combination of fluorescence microscopy and atomic force microscopy and, crucially, without applying any chemical or physical modifications that have previously been considered essential for maintaining the membrane integrity upon dehydration. We revealed that decreasing the hydration state of the membrane leads to an enhanced mixing of lipids characteristic of the liquid-disordered (Ld) phase with those forming the liquid-ordered (Lo) phase. This is associated with a 2-fold decrease in the hydrophobic mismatch between the Ld and Lo lipid phases and a 3-fold decrease in the line tension for the fully desiccated membrane. Importantly, the observed changes in the hydrophobic mismatch, line tension, and lipid miscibility are fully reversible upon subsequent rehydration of the membrane. These findings provide a deeper insight into the fundamental processes, such as cell-cell fusion, that require partial dehydration at the interface of two membranes.
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Affiliation(s)
- Emilia Krok
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland.
| | - Henri G Franquelim
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
- Leipzig University, Research and Transfer Center for Bioactive Matter, Deutscher Platz 5, 04103 Leipzig, Germany
| | - Madhurima Chattopadhyay
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland.
| | - Hanna Orlikowska-Rzeznik
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland.
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lukasz Piatkowski
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland.
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5
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Eilts J, Reinhard S, Michetschläger N, Werner C, Sauer M. Enhanced synaptic protein visualization by multicolor super-resolution expansion microscopy. NEUROPHOTONICS 2023; 10:044412. [PMID: 37886043 PMCID: PMC10599331 DOI: 10.1117/1.nph.10.4.044412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/28/2023]
Abstract
Significance Understanding the organization of biomolecules into complexes and their dynamics is crucial for comprehending cellular functions and dysfunctions, particularly in neuronal networks connected by synapses. In the last two decades, various powerful super-resolution (SR) microscopy techniques have been developed that produced stunning images of synapses and their molecular organization. However, current SR microscopy methods do not permit multicolor fluorescence imaging with 20 to 30 nm spatial resolution. Aim We developed a method that enables 4-color fluorescence imaging of synaptic proteins in neurons with 20 to 30 nm lateral resolution. Approach We used post-expansion immunolabeling of eightfold expanded hippocampal neurons in combination with Airyscan and structured illumination microscopy (SIM). Results We demonstrate that post-expansion immunolabeling of approximately eightfold expanded hippocampal neurons enables efficient labeling of synaptic proteins in crowded compartments with minimal linkage error and enables in combination with Airyscan and SIM four-color three-dimensional fluorescence imaging with 20 to 30 nm lateral resolution. Using immunolabeling of Synaptobrevin 2 as an efficient marker of the vesicle pool allowed us to identify individual synaptic vesicles colocalized with Rab3-interacting molecule 1 and 2 (RIM1/2), a marker of pre-synaptic fusion sites. Conclusions Our optimized expansion microscopy approach improves the visualization and location of pre- and post-synaptic proteins and can thus provide invaluable insights into the spatial organization of proteins at synapses.
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Affiliation(s)
- Janna Eilts
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Sebastian Reinhard
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Nikolas Michetschläger
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Christian Werner
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Markus Sauer
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
- University of Würzburg, Rudolf Virchow Center, Research Center for Integrative and Translational Bioimaging, Würzburg, Germany
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6
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Bogue D, Ryan G, Wassmer E, Research Consortium GE, Naik S. VAMP2 Gene-Related Neurodevelopmental Disorder: A Differential Diagnosis for Rett/Angelman-Type Spectrum of Disorders. Mol Syndromol 2023; 14:449-456. [PMID: 37901860 PMCID: PMC10601795 DOI: 10.1159/000530150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 03/08/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction VAMP2 is an instrumental protein in neuronal synaptic transmission in the brain, facilitating neurotransmitter release. It is encoded by the VAMP2 gene, and pathogenic variants in this gene cause neurodevelopmental features including early onset axial hypotonia, intellectual disability, and features of autism spectrum disorder. To date, only three types of allelic variants (loss of function, in-frame deletions, and missense variants) in the VAMP2 gene have been previously reported in 11 patients with learning difficulties. Here, we describe a patient in whom a novel de novo pathogenic variant in the VAMP2 gene was identified. Case Presentation A 15-month-old girl presented with early onset hypotonia, global developmental delay, learning difficulties, microcephaly, nystagmus, strabismus, and stereotypies. Later, she developed a sleep disorder, challenging behaviour with self-injury, and scoliosis. Gene agnostic analysis of whole genome sequencing data identified a novel de novo heterozygous missense variant c.197G>C (p.Arg66Pro) in the VAMP2 gene SNARE motif region. Discussion This is the fourth report describing VAMP2 gene-related neurodevelopmental disorder. This report adds to the genotype-phenotype correlation and highlights this condition as an important differential diagnosis of Rett/Angelman-type spectrum of disorders. Patients presenting with features of either Rett syndrome or Angelman syndrome, in whom genetic testing is not suggestive, should be evaluated for variants in the VAMP2 gene, given the significant overlap in clinical presentation of these disorders.
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Affiliation(s)
- Danielle Bogue
- West Midlands Clinical Genetics Unit, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
| | - Gavin Ryan
- West Midlands Regional Genetics Laboratory, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
| | - Evangeline Wassmer
- Department of Neurology, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
- Institute of Health and Neurodevelopment, Aston University, Birmingham, UK
| | | | - Swati Naik
- West Midlands Clinical Genetics Unit, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
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7
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Li Z, Wang J, O’Hagan MP, Huang F, Xia F, Willner I. Dynamic Fusion of Nucleic Acid Functionalized Nano-/Micro-Cell-Like Containments: From Basic Concepts to Applications. ACS NANO 2023; 17:15308-15327. [PMID: 37549398 PMCID: PMC10448756 DOI: 10.1021/acsnano.3c04415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/01/2023] [Indexed: 08/09/2023]
Abstract
Membrane fusion processes play key roles in biological transformations, such as endocytosis/exocytosis, signal transduction, neurotransmission, or viral infections, and substantial research efforts have been directed to emulate these functions by artificial means. The recognition and dynamic reconfiguration properties of nucleic acids provide a versatile means to induce membrane fusion. Here we address recent advances in the functionalization of liposomes or membranes with structurally engineered lipidated nucleic acids guiding the fusion of cell-like containments, and the biophysical and chemical parameters controlling the fusion of the liposomes will be discussed. Intermembrane bridging by duplex or triplex nucleic acids and light-induced activation of membrane-associated nucleic acid constituents provide the means for spatiotemporal fusion of liposomes or nucleic acid modified liposome fusion with native cell membranes. The membrane fusion processes lead to exchange of loads in the fused containments and are a means to integrate functional assemblies. This is exemplified with the operation of biocatalytic cascades and dynamic DNA polymerization/nicking or transcription machineries in fused protocell systems. Membrane fusion processes of protocell assemblies are found to have important drug-delivery, therapeutic, sensing, and biocatalytic applications. The future challenges and perspectives of DNA-guided fused containments and membranes are addressed.
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Affiliation(s)
- Zhenzhen Li
- The
Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Jianbang Wang
- The
Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Michael P. O’Hagan
- The
Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Fujian Huang
- State
Key Laboratory of Biogeology and Environmental Geology, Engineering
Research Center of Nano-Geomaterials of Ministry of Education, Faculty
of Materials Science and Chemistry, China
University of Geosciences, Wuhan 430074, People’s Republic of China
| | - Fan Xia
- State
Key Laboratory of Biogeology and Environmental Geology, Engineering
Research Center of Nano-Geomaterials of Ministry of Education, Faculty
of Materials Science and Chemistry, China
University of Geosciences, Wuhan 430074, People’s Republic of China
| | - Itamar Willner
- The
Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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8
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Machamer JB, Vazquez-Cintron EJ, Stenslik MJ, Pagarigan KT, Bradford AB, Ondeck CA, McNutt PM. Neuromuscular recovery from botulism involves multiple forms of compensatory plasticity. Front Cell Neurosci 2023; 17:1226194. [PMID: 37650071 PMCID: PMC10463753 DOI: 10.3389/fncel.2023.1226194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction Botulinum neurotoxin (BoNT) causes neuroparalytic disease and death by blocking neuromuscular transmission. There are no specific therapies for clinical botulism and the only treatment option is supportive care until neuromuscular function spontaneously recovers, which can take weeks or months after exposure. The highly specialized neuromuscular junction (NMJ) between phrenic motor neurons and diaphragm muscle fibers is the main clinical target of BoNT. Due to the difficulty in eliciting respiratory paralysis without a high mortality rate, few studies have characterized the neurophysiological mechanisms involved in diaphragm recovery from intoxication. Here, we develop a mouse model of botulism that involves partial paralysis of respiratory muscles with low mortality rates, allowing for longitudinal analysis of recovery. Methods and results Mice challenged by systemic administration of 0.7 LD50 BoNT/A developed physiological signs of botulism, such as respiratory depression and reduced voluntary running activity, that persisted for an average of 8-12 d. Studies in isolated hemidiaphragm preparations from intoxicated mice revealed profound reductions in nerve-elicited, tetanic and twitch muscle contraction strengths that recovered to baseline 21 d after intoxication. Despite apparent functional recovery, neurophysiological parameters remained depressed for 28 d, including end plate potential (EPP) amplitude, EPP success rate, quantal content (QC), and miniature EPP (mEPP) frequency. However, QC recovered more quickly than mEPP frequency, which could explain the discrepancy between muscle function studies and neurophysiological recordings. Hypothesizing that differential modulation of voltage-gated calcium channels (VGCC) contributed to the uncoupling of QC from mEPP frequency, pharmacological inhibition studies were used to study the contributions of different VGCCs to neurophysiological function. We found that N-type VGCC and P/Q-type VGCC partially restored QC but not mEPP frequency during recovery from paralysis, potentially explaining the accelerated recovery of evoked release versus spontaneous release. We identified additional changes that presumably compensate for reduced acetylcholine release during recovery, including increased depolarization of muscle fiber resting membrane potential and increased quantal size. Discussion In addition to identifying multiple forms of compensatory plasticity that occur in response to reduced NMJ function, it is expected that insights into the molecular mechanisms involved in recovery from neuromuscular paralysis will support new host-targeted treatments for multiple neuromuscular diseases.
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Affiliation(s)
- James B. Machamer
- BASF, Research Triangle Park, NC, United States
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | | | - Mallory J. Stenslik
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Kathleen T. Pagarigan
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Aaron B. Bradford
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Celinia A. Ondeck
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Patrick M. McNutt
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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Jusyte M, Blaum N, Böhme MA, Berns MMM, Bonard AE, Vámosi ÁB, Pushpalatha KV, Kobbersmed JRL, Walter AM. Unc13A dynamically stabilizes vesicle priming at synaptic release sites for short-term facilitation and homeostatic potentiation. Cell Rep 2023; 42:112541. [PMID: 37243591 DOI: 10.1016/j.celrep.2023.112541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/10/2023] [Accepted: 05/03/2023] [Indexed: 05/29/2023] Open
Abstract
Presynaptic plasticity adjusts neurotransmitter (NT) liberation. Short-term facilitation (STF) tunes synapses to millisecond repetitive activation, while presynaptic homeostatic potentiation (PHP) of NT release stabilizes transmission over minutes. Despite different timescales of STF and PHP, our analysis of Drosophila neuromuscular junctions reveals functional overlap and shared molecular dependence on the release-site protein Unc13A. Mutating Unc13A's calmodulin binding domain (CaM-domain) increases baseline transmission while blocking STF and PHP. Mathematical modeling suggests that Ca2+/calmodulin/Unc13A interaction plastically stabilizes vesicle priming at release sites and that CaM-domain mutation causes constitutive stabilization, thereby blocking plasticity. Labeling the functionally essential Unc13A MUN domain reveals higher STED microscopy signals closer to release sites following CaM-domain mutation. Acute phorbol ester treatment similarly enhances NT release and blocks STF/PHP in synapses expressing wild-type Unc13A, while CaM-domain mutation occludes this, indicating common downstream effects. Thus, Unc13A regulatory domains integrate signals across timescales to switch release-site participation for synaptic plasticity.
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Affiliation(s)
- Meida Jusyte
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Einstein Center for Neurosciences Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Natalie Blaum
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Mathias A Böhme
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Manon M M Berns
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Alix E Bonard
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Ábel B Vámosi
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Janus R L Kobbersmed
- Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark; Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alexander M Walter
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Einstein Center for Neurosciences Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.
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10
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Nakao H, Nagao M, Yamada T, Imamura K, Nozaki K, Ikeda K, Nakano M. Impact of transmembrane peptides on individual lipid motions and collective dynamics of lipid bilayers. Colloids Surf B Biointerfaces 2023; 228:113396. [PMID: 37311269 DOI: 10.1016/j.colsurfb.2023.113396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/15/2023] [Accepted: 06/05/2023] [Indexed: 06/15/2023]
Abstract
The fluid nature of lipid bilayers is indispensable for the dynamic regulation of protein function and membrane morphology in biological membranes. Membrane-spanning domains of proteins interact with surrounding lipids and alter the physical properties of lipid bilayers. However, there is no comprehensive view of the effects of transmembrane proteins on the membrane's physical properties. Here, we investigated the effects of transmembrane peptides with different flip-flop-promoting abilities on the dynamics of a lipid bilayer employing complemental fluorescence and neutron scattering techniques. The quasi-elastic neutron scattering and fluorescence experiments revealed that lateral diffusion of the lipid molecules and the acyl chain motions were inhibited by the inclusion of transmembrane peptides. The neutron spin-echo spectroscopy measurements indicated that the lipid bilayer became more rigid but more compressible and the membrane viscosity increased when the transmembrane peptides were incorporated into the membrane. These results suggest that the inclusion of rigid transmembrane structures hinders individual and collective lipid motions by slowing down lipid diffusion and increasing interleaflet coupling. The present study provides a clue for understanding how the local interactions between lipids and proteins change the collective dynamics of the lipid bilayers, and therefore, the function of biological membranes.
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Affiliation(s)
- Hiroyuki Nakao
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Michihiro Nagao
- National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, MD 20899-6102, USA; Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115, USA; Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
| | - Takeshi Yamada
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
| | - Koki Imamura
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Koichi Nozaki
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Keisuke Ikeda
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Minoru Nakano
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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11
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Su S, Chen M, Wu Y, Lin Q, Wang D, Sun J, Hai J. Fecal microbiota transplantation and short-chain fatty acids protected against cognitive dysfunction in a rat model of chronic cerebral hypoperfusion. CNS Neurosci Ther 2023; 29 Suppl 1:98-114. [PMID: 36627762 PMCID: PMC10314111 DOI: 10.1111/cns.14089] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/21/2022] [Accepted: 01/01/2023] [Indexed: 01/12/2023] Open
Abstract
AIMS Clear roles and mechanisms in explaining gut microbial dysbiosis and microbial metabolites short-chain fatty acids (SCFAs) alterations in chronic cerebral ischemic pathogenesis have yet to be explored. In this study, we investigated chronic cerebral hypoperfusion (CCH)-induced gut microbiota and metabolic profiles of SCFAs as well as the effects and mechanisms of fecal microbiota transplantation (FMT) and SCFAs treatment on CCH-induced hippocampal neuronal injury. METHODS Bilateral common carotid artery occlusion (BCCAo) was used to establish the CCH model. Gut microbiota and SCFAs profiles in feces and hippocampus were evaluated by 16S ribosomal RNA sequencing and gas chromatography-mass spectrometry. RNA sequencing analysis was performed in hippocampal tissues. The potential molecular pathways and differential genes were verified through western blot, immunoprecipitation, immunofluorescence, and ELISA. Cognitive function was assessed via the Morris water maze test. Ultrastructures of mitochondria and synapses were tested through a transmission electron microscope. RESULTS Chronic cerebral hypoperfusion induced decreased fecal acetic and propionic acid and reduced hippocampal acetic acid, which were reversed after FMT and SCFAs administration by changing fecal microbial community structure and compositions. Furthermore, in the hippocampus, FMT and SCFAs replenishment exerted anti-neuroinflammatory effects through inhibiting microglial and astrocytic activation as well as switching microglial phenotype from M1 toward M2. Moreover, FMT and SCFAs treatment alleviated neuronal loss and microglia-mediated synaptic loss and maintained the normal process of synaptic vesicle fusion and release, resulting in the improvement of synaptic plasticity. In addition, FMT and SCFAs supplement prevented oxidative phosphorylation dysfunction via mitochondrial metabolic reprogramming. The above effects of FMT and SCFAs treatment led to the inhibition of CCH-induced cognitive impairment. CONCLUSION Our findings highlight FMT and SCFAs replenishment would be the feasible gut microbiota-based strategy to mitigate chronic cerebral ischemia-induced neuronal injury.
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Affiliation(s)
- Shao‐Hua Su
- Department of Neurosurgery, Tongji Hospital, School of MedicineTongji UniversityShanghaiChina
| | - Ming Chen
- Department of Neurosurgery, Xinhua hospital, School of MedicineShanghai Jiao Tong UniversityShanghaiChina
| | - Yi‐Fang Wu
- Department of Neurosurgery, Tongji Hospital, School of MedicineTongji UniversityShanghaiChina
| | - Qi Lin
- Department of Pharmacy, Institutes of Medical Sciences, School of MedicineShanghai Jiao Tong UniversityShanghaiChina
| | - Da‐Peng Wang
- Department of Neurosurgery, Tongji Hospital, School of MedicineTongji UniversityShanghaiChina
| | - Jun Sun
- Department of Neurosurgery, Tongji Hospital, School of MedicineTongji UniversityShanghaiChina
| | - Jian Hai
- Department of Neurosurgery, Tongji Hospital, School of MedicineTongji UniversityShanghaiChina
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12
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Miyajima A, Nakao H, Ikeda K, Nakano M. The Nanometer-Scale Proximity of Bilayers Facilitates Intermembrane Lipid Transfer. J Phys Chem Lett 2023; 14:4172-4178. [PMID: 37114850 DOI: 10.1021/acs.jpclett.3c00154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Biological membranes approach one another in various biological phenomena, such as lipid transport at membrane contact sites and membrane fusion. The proximity of two bilayers may cause environmental changes in the interbilayer space and alter the dynamics of lipid molecules. Here, we investigate the structure and dynamics of vesicles aggregated due to the depletion attraction caused by polyethylene glycol (PEG) through static and dynamic small-angle neutron scattering. Manipulation of the interbilayer distance using PEG-conjugated lipids reveals that lipid molecules rapidly transfer between vesicles when the opposing bilayers are within ∼2 nm of each other. This distance corresponds to a region in which water molecules are more structured than in bulk water. Kinetic analysis suggests that the decrease in water entropy is responsible for the progression of lipid transfer. These results provide a basis for understanding the dynamic function of biomembranes in confined regions.
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Affiliation(s)
- Ayari Miyajima
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Hiroyuki Nakao
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Keisuke Ikeda
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Minoru Nakano
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
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13
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Uzay B, Kavalali ET. Genetic disorders of neurotransmitter release machinery. Front Synaptic Neurosci 2023; 15:1148957. [PMID: 37066095 PMCID: PMC10102358 DOI: 10.3389/fnsyn.2023.1148957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Synaptic neurotransmitter release is an evolutionarily conserved process that mediates rapid information transfer between neurons as well as several peripheral tissues. Release of neurotransmitters are ensured by successive events such as synaptic vesicle docking and priming that prepare synaptic vesicles for rapid fusion. These events are orchestrated by interaction of different presynaptic proteins and are regulated by presynaptic calcium. Recent studies have identified various mutations in different components of neurotransmitter release machinery resulting in aberrant neurotransmitter release, which underlie a wide spectrum of psychiatric and neurological symptoms. Here, we review how these genetic alterations in different components of the core neurotransmitter release machinery affect the information transfer between neurons and how aberrant synaptic release affects nervous system function.
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Affiliation(s)
- Burak Uzay
- Vanderbilt Brain Institute, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - Ege T. Kavalali
- Vanderbilt Brain Institute, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
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14
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Ouyang X, Wu B, Yu H, Dong B. DYRK1-mediated phosphorylation of endocytic components is required for extracellular lumen expansion in ascidian notochord. Biol Res 2023; 56:10. [PMID: 36899423 PMCID: PMC10007804 DOI: 10.1186/s40659-023-00422-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/01/2023] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND The biological tube is a basal biology structure distributed in all multicellular animals, from worms to humans, and has diverse biological functions. Formation of tubular system is crucial for embryogenesis and adult metabolism. Ascidian Ciona notochord lumen is an excellent in vivo model for tubulogenesis. Exocytosis has been known to be essential for tubular lumen formation and expansion. The roles of endocytosis in tubular lumen expansion remain largely unclear. RESULTS In this study, we first identified a dual specificity tyrosine-phosphorylation-regulated kinase 1 (DYRK1), the protein kinase, which was upregulated and required for ascidian notochord extracellular lumen expansion. We demonstrated that DYRK1 interacted with and phosphorylated one of the endocytic components endophilin at Ser263 that was essential for notochord lumen expansion. Moreover, through phosphoproteomic sequencing, we revealed that in addition to endophilin, the phosphorylation of other endocytic components was also regulated by DYRK1. The loss of function of DYRK1 disturbed endocytosis. Then, we demonstrated that clathrin-mediated endocytosis existed and was required for notochord lumen expansion. In the meantime, the results showed that the secretion of notochord cells is vigorous in the apical membrane. CONCLUSIONS We found the co-existence of endocytosis and exocytosis activities in apical membrane during lumen formation and expansion in Ciona notochord. A novel signaling pathway is revealed that DYRK1 regulates the endocytosis by phosphorylation that is required for lumen expansion. Our finding thus indicates a dynamic balance between endocytosis and exocytosis is crucial to maintain apical membrane homeostasis that is essential for lumen growth and expansion in tubular organogenesis.
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Affiliation(s)
- Xiuke Ouyang
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Bingtong Wu
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Haiyan Yu
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Bo Dong
- Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China. .,Laoshan Laboratory, Qingdao, 266237, China. .,Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
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15
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Garner CC, Ackermann F. Synaptic logistics: The presynaptic scaffold protein Piccolo a nodal point tuning synaptic vesicle recycling, maintenance and integrity. Mol Cell Neurosci 2023; 124:103795. [PMID: 36436725 DOI: 10.1016/j.mcn.2022.103795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Properly working synapses are one important guarantor for a functional and healthy brain. They are small, densely packed structures, where information is transmitted through the release of neurotransmitters from synaptic vesicles (SVs). The latter cycle within the presynaptic terminal as they first fuse with the plasma membrane to deliver their neurotransmitter, and afterwards become recycled and prepared for a new release event. The synapse is an autonomous structure functioning mostly independent of the neuronal soma. Dysfunction in synaptic processes associated with local insults or genetic abnormalities can directly compromise synapse function and integrity and subsequently lead to the onset of neurodegenerative diseases. Therefore, measures need to be in place counteracting these threats for instance through the continuous replacement of old and damaged SV proteins. Interestingly recent studies show that the presynaptic scaffolding protein Piccolo contributes to health, function and integrity of synapses, as it mediates the delivery of synaptic proteins from the trans-Golgi network (TGN) towards synapses, as well as the local recycling and turnover of SV proteins within synaptic terminals. It can fulfill these various tasks through its multi-domain structure and ability to interact with numerous binding partners. In addition, Piccolo has recently been linked with the early onset neurodegenerative disease Pontocerebellar Hypoplasia Type 3 (PCH3) further underlying its importance for neuronal health. In this review, we will focus on Piccolo's contributions to synapse function, health and integrity and make a connection how those may contribute to the disease pattern of PCH3.
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Affiliation(s)
- Craig C Garner
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Germany
| | - Frauke Ackermann
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
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16
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Lévêque C, Maulet Y, Wang Q, Rame M, Rodriguez L, Mochida S, Sangiardi M, Youssouf F, Iborra C, Seagar M, Vitale N, El Far O. A Role for the V0 Sector of the V-ATPase in Neuroexocytosis: Exogenous V0d Blocks Complexin and SNARE Interactions with V0c. Cells 2023; 12:cells12050750. [PMID: 36899886 PMCID: PMC10001230 DOI: 10.3390/cells12050750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
V-ATPase is an important factor in synaptic vesicle acidification and is implicated in synaptic transmission. Rotation in the extra-membranous V1 sector drives proton transfer through the membrane-embedded multi-subunit V0 sector of the V-ATPase. Intra-vesicular protons are then used to drive neurotransmitter uptake by synaptic vesicles. V0a and V0c, two membrane subunits of the V0 sector, have been shown to interact with SNARE proteins, and their photo-inactivation rapidly impairs synaptic transmission. V0d, a soluble subunit of the V0 sector strongly interacts with its membrane-embedded subunits and is crucial for the canonic proton transfer activity of the V-ATPase. Our investigations show that the loop 1.2 of V0c interacts with complexin, a major partner of the SNARE machinery and that V0d1 binding to V0c inhibits this interaction, as well as V0c association with SNARE complex. The injection of recombinant V0d1 in rat superior cervical ganglion neurons rapidly reduced neurotransmission. In chromaffin cells, V0d1 overexpression and V0c silencing modified in a comparable manner several parameters of unitary exocytotic events. Our data suggest that V0c subunit promotes exocytosis via interactions with complexin and SNAREs and that this activity can be antagonized by exogenous V0d.
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Affiliation(s)
- Christian Lévêque
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Yves Maulet
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
| | - Marion Rame
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
| | - Léa Rodriguez
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
| | - Marion Sangiardi
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Fahamoe Youssouf
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Cécile Iborra
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Michael Seagar
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
- Correspondence: (N.V.); or (O.E.F.); Tel.: +33-(0)3-8845-6712 (N.V.); +33-(0)4-9169-8860 (O.E.F.)
| | - Oussama El Far
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
- Correspondence: (N.V.); or (O.E.F.); Tel.: +33-(0)3-8845-6712 (N.V.); +33-(0)4-9169-8860 (O.E.F.)
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17
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Flores-Montero K, Berberián MV, Mayorga LS, Tomes CN, Ruete MC. The molecular chaperone cysteine string protein is required for monomeric SNARE proteins to assemble in trans-complexes during human sperm acrosomal exocytosis†. Biol Reprod 2023; 108:229-240. [PMID: 36308432 DOI: 10.1093/biolre/ioac196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/06/2022] [Accepted: 10/24/2022] [Indexed: 11/13/2022] Open
Abstract
Membrane fusion in sperm cells is crucial for acrosomal exocytosis and must be preserved to ensure fertilizing capacity. Evolutionarily conserved protein machinery regulates acrosomal exocytosis. Molecular chaperones play a vital role in spermatogenesis and post-testicular maturation. Cysteine string protein (CSP) is a member of the Hsp40 co-chaperones, and the participation of molecular chaperones in acrosomal exocytosis is poorly understood. In particular, the role of CSP in acrosomal exocytosis has not been reported so far. Using western blot and indirect immunofluorescence, we show that CSP is present in human sperm, is palmitoylated, and predominantly bound to membranes. Moreover, using functional assays and transmission electron microscopy, we report that blocking the function of CSP avoided the assembly of trans-complexes and inhibited exocytosis. In summary, here, we describe the presence of CSP in human sperm and show that this protein has an essential role in membrane fusion during acrosomal exocytosis mediating the trans-SNARE complex assembly between the outer acrosomal and plasma membranes. In general, understanding CSP's role is critical in identifying new biomarkers and generating new rational-based approaches to treat male infertility.
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Affiliation(s)
- Karina Flores-Montero
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Victoria Berberián
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Ciencias Básicas - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Luis Segundo Mayorga
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia Nora Tomes
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Celeste Ruete
- Instituto de Histología y Embriología de Mendoza - Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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18
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Grasso EM, Terakawa MS, Lai AL, Xue Xie Y, Ramlall TF, Freed JH, Eliezer D. Membrane Binding Induces Distinct Structural Signatures in the Mouse Complexin-1C-Terminal Domain. J Mol Biol 2023; 435:167710. [PMID: 35777466 PMCID: PMC9794636 DOI: 10.1016/j.jmb.2022.167710] [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: 05/10/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 02/04/2023]
Abstract
Complexins play a critical role in regulating SNARE-mediated exocytosis of synaptic vesicles. Evolutionary divergences in complexin function have complicated our understanding of the role these proteins play in inhibiting the spontaneous fusion of vesicles. Previous structural and functional characterizations of worm and mouse complexins have indicated the membrane curvature-sensing C-terminal domain of these proteins is responsible for differences in inhibitory function. We have characterized the structure and dynamics of the mCpx1 CTD in the absence and presence of membranes and membrane mimetics using NMR, ESR, and optical spectroscopies. In the absence of lipids, the mCpx1 CTD features a short helix near its N-terminus and is otherwise disordered. In the presence of micelles and small unilamellar vesicles, the mCpx1 CTD forms a discontinuous helical structure in its C-terminal 20 amino acids, with no preference for specific lipid compositions. In contrast, the mCpx1 CTD shows distinct compositional preferences in its interactions with large unilamellar vesicles. These studies identify structural divergences in the mCpx1 CTD relative to the wCpx1 CTD in regions that are known to be critical to the wCpx1 CTD's role in inhibiting spontaneous fusion of synaptic vesicles, suggesting a potential structural basis for evolutionary divergences in complexin function.1.
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Affiliation(s)
- Emily M Grasso
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States
| | - Mayu S Terakawa
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States
| | - Alex L Lai
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
| | - Ying Xue Xie
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States
| | - Trudy F Ramlall
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States
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19
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Yan C, Jiang J, Yang Y, Geng X, Dong W. The function of VAMP2 in mediating membrane fusion: An overview. Front Mol Neurosci 2022; 15:948160. [PMID: 36618823 PMCID: PMC9816800 DOI: 10.3389/fnmol.2022.948160] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Vesicle-associated membrane protein 2 (VAMP2, also known as synaptobrevin-2), encoded by VAMP2 in humans, is a key component of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. VAMP2 combined with syntaxin-1A (SYX-1A) and synaptosome-associated protein 25 (SNAP-25) produces a force that induces the formation of fusion pores, thereby mediating the fusion of synaptic vesicles and the release of neurotransmitters. VAMP2 is largely unstructured in the absence of interaction partners. Upon interaction with other SNAREs, the structure of VAMP2 stabilizes, resulting in the formation of four structural domains. In this review, we highlight the current knowledge of the roles of the VAMP2 domains and the interaction between VAMP2 and various fusion-related proteins in the presynaptic cytoplasm during the fusion process. Our summary will contribute to a better understanding of the roles of the VAMP2 protein in membrane fusion.
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Affiliation(s)
- Chong Yan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Jie Jiang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yuan Yang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Xiaoqi Geng
- Department of Neurosurgery, Neurosurgical Clinical Research Center of Sichuan Province, Affiliated Hospital of Southwest Medical University, Luzhou, China,*Correspondence: Xiaoqi Geng,
| | - Wei Dong
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China,Wei Dong,
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20
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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21
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Yeo XY, Lim YT, Chae WR, Park C, Park H, Jung S. Alterations of presynaptic proteins in autism spectrum disorder. Front Mol Neurosci 2022; 15:1062878. [DOI: 10.3389/fnmol.2022.1062878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022] Open
Abstract
The expanded use of hypothesis-free gene analysis methods in autism research has significantly increased the number of genetic risk factors associated with the pathogenesis of autism. A further examination of the implicated genes directly revealed the involvement in processes pertinent to neuronal differentiation, development, and function, with a predominant contribution from the regulators of synaptic function. Despite the importance of presynaptic function in synaptic transmission, the regulation of neuronal network activity, and the final behavioral output, there is a relative lack of understanding of the presynaptic contribution to the pathology of autism. Here, we will review the close association among autism-related mutations, autism spectrum disorders (ASD) phenotypes, and the altered presynaptic protein functions through a systematic examination of the presynaptic risk genes relating to the critical stages of synaptogenesis and neurotransmission.
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22
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Wang X, Yu D, Wang H, Lei Z, Zhai Y, Sun M, Chen S, Yin P. Rab3 and synaptotagmin proteins in the regulation of vesicle fusion and neurotransmitter release. Life Sci 2022; 309:120995. [PMID: 36167148 DOI: 10.1016/j.lfs.2022.120995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/13/2022] [Accepted: 09/21/2022] [Indexed: 10/31/2022]
Abstract
Ca2+-triggered neurotransmitter release involves complex regulatory mechanisms, including a series of protein-protein interactions. Three proteins, synaptobrevin (VAMP), synaptosomal-associated protein of 25kDa (SNAP-25) and syntaxin, constitute the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) core complex that plays key roles in controlling vesicle fusion and exocytosis. Many other proteins participate in the regulation of the processes via direct and/or indirect interaction with the SNARE complex. Although much effort has been made, the regulatory mechanism for exocytosis is still not completely clear. Accumulated evidence indicates that the small GTPase Rab3 and synaptotagmin proteins play important regulatory roles during vesicle fusion and neurotransmitter release. This review outlines our present understanding of the two regulatory proteins, with the focus on the interaction of Rab3 with synaptotagmin in the regulatory process.
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Affiliation(s)
- Xianchun Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Dianmei Yu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Haiyan Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Zhixiang Lei
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Yiwen Zhai
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Minlu Sun
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Si Chen
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Panfeng Yin
- State Key Laboratory of Developmental Biology of Freshwater Fish, Protein Chemistry Laboratory, College of Life Sciences, Hunan Normal University, Changsha 410081, China
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Liang Q, Ofosuhene AP, Kiessling V, Liang B, Kreutzberger AJB, Tamm LK, Cafiso DS. Complexin-1 and synaptotagmin-1 compete for binding sites on membranes containing PtdInsP 2. Biophys J 2022; 121:3370-3380. [PMID: 36016497 PMCID: PMC9515229 DOI: 10.1016/j.bpj.2022.08.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/28/2022] [Accepted: 08/19/2022] [Indexed: 11/25/2022] Open
Abstract
Complexin-1 is an essential protein for neuronal exocytosis that acts to depress spontaneous fusion events while enhancing evoked neurotransmitter release. In addition to binding soluble N-ethylmaleimide-sensitive factor attachment protein receptors, it is well established that complexin associates with membranes in a manner that depends upon membrane curvature. In the present work, we examine the membrane binding of complexin using electron paramagnetic resonance spectroscopy, fluorescence anisotropy, and total internal reflection fluorescence microscopy. The apparent membrane affinity of complexin is found to strongly depend upon the concentration of protein used in the binding assay, and this is a result of a limited number of binding sites for complexin on the membrane interface. Although both the N- and C-terminal regions of complexin associate with the membrane interface, membrane affinity is driven by its C-terminus. Complexin prefers to bind liquid-disordered membrane phases and shows an enhanced affinity toward membranes containing phosphatidylinositol 4-5-bisphosphate (PI(4,5)P2). In the presence of PI(4,5)P2, complexin is displaced from the membrane surface by proteins that bind to or sequester PI(4,5)P2. In particular, the neuronal calcium sensor synaptotagmin-1 displaces complexin from the membrane but only when PI(4,5)P2 is present. Complexin and synaptotagmin compete on the membrane interface in the presence of PI(4,5)P2, and this interaction may play a role in calcium-triggered exocytosis by displacing complexin from its fusion-inhibiting state.
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Affiliation(s)
- Qian Liang
- Department of Chemistry, University of Virginia, Charlottesville, Virginia
| | - Akosua P Ofosuhene
- Department of Chemistry, University of Virginia, Charlottesville, Virginia
| | - Volker Kiessling
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia; Center for Membrane Biology, University of Virginia, Charlottesville, Virginia
| | - Binyong Liang
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia; Center for Membrane Biology, University of Virginia, Charlottesville, Virginia
| | - Alex J B Kreutzberger
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia; Center for Membrane Biology, University of Virginia, Charlottesville, Virginia
| | - Lukas K Tamm
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia; Center for Membrane Biology, University of Virginia, Charlottesville, Virginia
| | - David S Cafiso
- Department of Chemistry, University of Virginia, Charlottesville, Virginia; Center for Membrane Biology, University of Virginia, Charlottesville, Virginia.
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24
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Tanaka H, Kanda M, Shimizu D, Tanaka C, Inokawa Y, Hattori N, Hayashi M, Nakayama G, Kodera Y. Transcriptomic profiling on localized gastric cancer identified CPLX1 as a gene promoting malignant phenotype of gastric cancer and a predictor of recurrence after surgery and subsequent chemotherapy. J Gastroenterol 2022; 57:640-653. [PMID: 35726075 DOI: 10.1007/s00535-022-01884-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 05/20/2022] [Indexed: 02/04/2023]
Abstract
BACKGROUND Localized gastric cancer (GC) becomes fatal once recurring. We still have room for improving their prognoses. METHODS Transcriptomic analysis was done on surgically resected specimens of 16 patients with UICC stage III GC who underwent curative gastrectomy and adjuvant oral fluoropyrimidine monotherapy. Four of them were free from disease for longer than 5 years, and the others experienced metachronous metastasis within 2 years after surgery. Quantitative RT-PCR determined mRNA expression levels of primary gastric cancer tissues, which were collected from 180 patients who underwent gastric resection for stage II-III GC without preoperative treatment between 2001 and 2014. We tested alteration of malignant phenotypes including drug resistance of GC cell lines by siRNA and shRNA-mediated knockdown and forced expression experiments. RESULTS CPLX1 was identified as a candidate biomarker for GC recurrence among 57,749 genes. Inhibiting and forced expression experiments indicated that CPLX1 promotes proliferation, motility, and invasiveness of GC cells, and decreases apoptosis and sensitivity to fluorouracil. Subcutaneous xenograft mouse models revealed that shRNA-mediated knockdown of CPLX1 also attenuated tumor growth of MKN1 cells in vivo. Overexpression of CPLX1 in gastric cancer tissue correlated with worse prognosis and was an independent risk factor for peritoneal recurrence in subgroups receiving adjuvant chemotherapy. CONCLUSIONS CPLX1 may represent a biomarker for recurrence of gastric cancer and a target for therapy.
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Affiliation(s)
- Haruyoshi Tanaka
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Mitsuro Kanda
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Dai Shimizu
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Chie Tanaka
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Yoshikuni Inokawa
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Norifumi Hattori
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Masamichi Hayashi
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Goro Nakayama
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Yasuhiro Kodera
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
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25
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The Effect of Aggregated Alpha Synuclein on Synaptic and Axonal Proteins in Parkinson’s Disease—A Systematic Review. Biomolecules 2022; 12:biom12091199. [PMID: 36139038 PMCID: PMC9496556 DOI: 10.3390/biom12091199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
α-synuclein is a core component of Lewy bodies, one of the pathological hallmarks of Parkinson’s disease. Aggregated α-synuclein can impair both synaptic functioning and axonal transport. However, understanding the pathological role that α-synuclein plays at a cellular level is complicated as existing findings are multifaceted and dependent on the mutation, the species, and the quantity of the protein that is involved. This systematic review aims to stratify the research findings to develop a more comprehensive understanding of the role of aggregated α-synuclein on synaptic and axonal proteins in Parkinson’s disease models. A literature search of the PubMed, Scopus, and Web of Science databases was conducted and a total of 39 studies were included for analysis. The review provides evidence for the dysregulation or redistribution of synaptic and axonal proteins due to α-synuclein toxicity. However, due to the high quantity of variables that were used in the research investigations, it was challenging to ascertain exactly what effect α-synuclein has on the expression of the proteins. A more standardized experimental approach regarding the variables that are employed in future studies is crucial so that existing literature can be consolidated. New research involving aggregated α-synuclein at the synapse and regarding axonal transport could be advantageous in guiding new treatment solutions.
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26
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Gething C, Ferrar J, Misra B, Howells G, Andrzejewski AL, Bowen ME, Choi UB. Conformational change of Syntaxin-3b in regulating SNARE complex assembly in the ribbon synapses. Sci Rep 2022; 12:9261. [PMID: 35661757 PMCID: PMC9166750 DOI: 10.1038/s41598-022-09654-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/10/2022] [Indexed: 11/09/2022] Open
Abstract
Neurotransmitter release of synaptic vesicles relies on the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, consisting of syntaxin and SNAP-25 on the plasma membrane and synaptobrevin on the synaptic vesicle. The formation of the SNARE complex progressively zippers towards the membranes, which drives membrane fusion between the plasma membrane and the synaptic vesicle. However, the underlying molecular mechanism of SNARE complex regulation is unclear. In this study, we investigated the syntaxin-3b isoform found in the retinal ribbon synapses using single-molecule fluorescence resonance energy transfer (smFRET) to monitor the conformational changes of syntaxin-3b that modulate the SNARE complex formation. We found that syntaxin-3b is predominantly in a self-inhibiting closed conformation, inefficiently forming the ternary SNARE complex. Conversely, a phosphomimetic mutation (T14E) at the N-terminal region of syntaxin-3b promoted the open conformation, similar to the constitutively open form of syntaxin LE mutant. When syntaxin-3b is bound to Munc18-1, SNARE complex formation is almost completely blocked. Surprisingly, the T14E mutation of syntaxin-3b partially abolishes Munc18-1 regulation, acting as a conformational switch to trigger SNARE complex assembly. Thus, we suggest a model where the conformational change of syntaxin-3b induced by phosphorylation initiates the release of neurotransmitters in the ribbon synapses.
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Affiliation(s)
- Claire Gething
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Joshua Ferrar
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Bishal Misra
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Giovanni Howells
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Mark E Bowen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.,Quantum-Si, Inc, Guilford, CT, 06437, USA
| | - Ucheor B Choi
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA. .,Quantum-Si, Inc, Guilford, CT, 06437, USA.
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27
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Szule JA. Hypothesis Relating the Structure, Biochemistry and Function of Active Zone Material Macromolecules at a Neuromuscular Junction. Front Synaptic Neurosci 2022; 13:798225. [PMID: 35069169 PMCID: PMC8766674 DOI: 10.3389/fnsyn.2021.798225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/14/2021] [Indexed: 12/22/2022] Open
Abstract
This report integrates knowledge of in situ macromolecular structures and synaptic protein biochemistry to propose a unified hypothesis for the regulation of certain vesicle trafficking events (i.e., docking, priming, Ca2+-triggering, and membrane fusion) that lead to neurotransmitter secretion from specialized “active zones” of presynaptic axon terminals. Advancements in electron tomography, to image tissue sections in 3D at nanometer scale resolution, have led to structural characterizations of a network of different classes of macromolecules at the active zone, called “Active Zone Material’. At frog neuromuscular junctions, the classes of Active Zone Material macromolecules “top-masts”, “booms”, “spars”, “ribs” and “pins” direct synaptic vesicle docking while “pins”, “ribs” and “pegs” regulate priming to influence Ca2+-triggering and membrane fusion. Other classes, “beams”, “steps”, “masts”, and “synaptic vesicle luminal filaments’ likely help organize and maintain the structural integrity of active zones. Extensive studies on the biochemistry that regulates secretion have led to comprehensive characterizations of the many conserved proteins universally involved in these trafficking events. Here, a hypothesis including a partial proteomic atlas of Active Zone Material is presented which considers the common roles, binding partners, physical features/structure, and relative positioning in the axon terminal of both the proteins and classes of macromolecules involved in the vesicle trafficking events. The hypothesis designates voltage-gated Ca2+ channels and Ca2+-gated K+ channels to ribs and pegs that are connected to macromolecules that span the presynaptic membrane at the active zone. SNARE proteins (Syntaxin, SNAP25, and Synaptobrevin), SNARE-interacting proteins Synaptotagmin, Munc13, Munc18, Complexin, and NSF are designated to ribs and/or pins. Rab3A and Rabphillin-3A are designated to top-masts and/or booms and/or spars. RIM, Bassoon, and Piccolo are designated to beams, steps, masts, ribs, spars, booms, and top-masts. Spectrin is designated to beams. Lastly, the luminal portions of SV2 are thought to form the bulk of the observed synaptic vesicle luminal filaments. The goal here is to help direct future studies that aim to bridge Active Zone Material structure, biochemistry, and function to ultimately determine how it regulates the trafficking events in vivo that lead to neurotransmitter secretion.
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28
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Wichmann C, Kuner T. Heterogeneity of glutamatergic synapses: cellular mechanisms and network consequences. Physiol Rev 2022; 102:269-318. [PMID: 34727002 DOI: 10.1152/physrev.00039.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chemical synapses are commonly known as a structurally and functionally highly diverse class of cell-cell contacts specialized to mediate communication between neurons. They represent the smallest "computational" unit of the brain and are typically divided into excitatory and inhibitory as well as modulatory categories. These categories are subdivided into diverse types, each representing a different structure-function repertoire that in turn are thought to endow neuronal networks with distinct computational properties. The diversity of structure and function found among a given category of synapses is referred to as heterogeneity. The main building blocks for this heterogeneity are synaptic vesicles, the active zone, the synaptic cleft, the postsynaptic density, and glial processes associated with the synapse. Each of these five structural modules entails a distinct repertoire of functions, and their combination specifies the range of functional heterogeneity at mammalian excitatory synapses, which are the focus of this review. We describe synapse heterogeneity that is manifested on different levels of complexity ranging from the cellular morphology of the pre- and postsynaptic cells toward the expression of different protein isoforms at individual release sites. We attempt to define the range of structural building blocks that are used to vary the basic functional repertoire of excitatory synaptic contacts and discuss sources and general mechanisms of synapse heterogeneity. Finally, we explore the possible impact of synapse heterogeneity on neuronal network function.
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Affiliation(s)
- Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Institute for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg, Germany
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29
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Li L, Liu H, Krout M, Richmond JE, Wang Y, Bai J, Weeratunga S, Collins BM, Ventimiglia D, Yu Y, Xia J, Tang J, Liu J, Hu Z. A novel dual Ca2+ sensor system regulates Ca2+-dependent neurotransmitter release. J Cell Biol 2021; 220:211787. [PMID: 33570571 PMCID: PMC7883739 DOI: 10.1083/jcb.202008121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/19/2020] [Accepted: 01/15/2021] [Indexed: 02/08/2023] Open
Abstract
Ca2+-dependent neurotransmitter release requires synaptotagmins as Ca2+ sensors to trigger synaptic vesicle (SV) exocytosis via binding of their tandem C2 domains—C2A and C2B—to Ca2+. We have previously demonstrated that SNT-1, a mouse synaptotagmin-1 (Syt1) homologue, functions as the fast Ca2+ sensor in Caenorhabditis elegans. Here, we report a new Ca2+ sensor, SNT-3, which triggers delayed Ca2+-dependent neurotransmitter release. snt-1;snt-3 double mutants abolish evoked synaptic transmission, demonstrating that C. elegans NMJs use a dual Ca2+ sensor system. SNT-3 possesses canonical aspartate residues in both C2 domains, but lacks an N-terminal transmembrane (TM) domain. Biochemical evidence demonstrates that SNT-3 binds both Ca2+ and the plasma membrane. Functional analysis shows that SNT-3 is activated when SNT-1 function is impaired, triggering SV release that is loosely coupled to Ca2+ entry. Compared with SNT-1, which is tethered to SVs, SNT-3 is not associated with SV. Eliminating the SV tethering of SNT-1 by removing the TM domain or the whole N terminus rescues fast release kinetics, demonstrating that cytoplasmic SNT-1 is still functional and triggers fast neurotransmitter release, but also exhibits decreased evoked amplitude and release probability. These results suggest that the fast and slow properties of SV release are determined by the intrinsically different C2 domains in SNT-1 and SNT-3, rather than their N-termini–mediated membrane tethering. Our findings therefore reveal a novel dual Ca2+ sensor system in C. elegans and provide significant insights into Ca2+-regulated exocytosis.
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Affiliation(s)
- Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Mia Krout
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Yu Wang
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Jihong Bai
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Saroja Weeratunga
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Donovan Ventimiglia
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY
| | - Yi Yu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jingyao Xia
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jing Tang
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jie Liu
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
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30
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Akkouh IA, Hribkova H, Grabiec M, Budinska E, Szabo A, Kasparek T, Andreassen OA, Sun YM, Djurovic S. Derivation and Molecular Characterization of a Morphological Subpopulation of Human iPSC Astrocytes Reveal a Potential Role in Schizophrenia and Clozapine Response. Schizophr Bull 2021; 48:190-198. [PMID: 34357384 PMCID: PMC8781347 DOI: 10.1093/schbul/sbab092] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Astrocytes are the most abundant cell type in the human brain and are important regulators of several critical cellular functions, including synaptic transmission. Although astrocytes are known to play a central role in the etiology and pathophysiology of schizophrenia, little is known about their potential involvement in clinical response to the antipsychotic clozapine. Moreover, astrocytes display a remarkable degree of morphological diversity, but the potential contribution of astrocytic subtypes to disease biology and drug response has received little attention. Here, we used state-of-the-art human induced pluripotent stem cell (hiPSC) technology to derive a morphological subtype of astrocytes from healthy individuals and individuals with schizophrenia, including responders and nonresponders to clozapine. Using functional assays and transcriptional profiling, we identified a distinct gene expression signature highly specific to schizophrenia as shown by disease association analysis of more than 10 000 diseases. We further found reduced levels of both glutamate and the NMDA receptor coagonist d-serine in subtype astrocytes derived from schizophrenia patients, and that exposure to clozapine only rescued this deficiency in cells from clozapine responders, providing further evidence that d-serine in particular, and NMDA receptor-mediated glutamatergic neurotransmission in general, could play an important role in disease pathophysiology and clozapine action. Our study represents a first attempt to explore the potential contribution of astrocyte diversity to schizophrenia pathophysiology using a human cellular model. Our findings suggest that specialized subtypes of astrocytes could be important modulators of disease pathophysiology and clinical drug response, and warrant further investigations.
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Affiliation(s)
- Ibrahim A Akkouh
- NORMENT, Institute of Clinical Medicine, University of Oslo, Oslo, Norway,Department of Medical Genetics, Oslo University Hospital, Oslo, Norway,To whom correspondence should be addressed; Postbox 4956, Nydalen, Building 49, 0424 Oslo, Norway; tel: 4798470640, e-mail:
| | - Hana Hribkova
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Marta Grabiec
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Eva Budinska
- Bioinformatics in Translational Research, RECETOX & IBA, Masaryk University, Brno, Czech Republic
| | - Attila Szabo
- NORMENT, Institute of Clinical Medicine, University of Oslo, Oslo, Norway,Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Tomas Kasparek
- Department of Psychiatry, Faculty of Medicine and University Hospital Brno, Brno, Czech Republic
| | - Ole A Andreassen
- NORMENT, Institute of Clinical Medicine, University of Oslo, Oslo, Norway,Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Yuh-Man Sun
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway,NORMENT, Department of Clinical Science, University of Bergen, Bergen, Norway
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Carrillo-Baltodano AM, Seudre O, Guynes K, Martín-Durán JM. Early embryogenesis and organogenesis in the annelid Owenia fusiformis. EvoDevo 2021; 12:5. [PMID: 33971947 PMCID: PMC8111721 DOI: 10.1186/s13227-021-00176-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/23/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Annelids are a diverse group of segmented worms within Spiralia, whose embryos exhibit spiral cleavage and a variety of larval forms. While most modern embryological studies focus on species with unequal spiral cleavage nested in Pleistoannelida (Sedentaria + Errantia), a few recent studies looked into Owenia fusiformis, a member of the sister group to all remaining annelids and thus a key lineage to understand annelid and spiralian evolution and development. However, the timing of early cleavage and detailed morphogenetic events leading to the formation of the idiosyncratic mitraria larva of O. fusiformis remain largely unexplored. RESULTS Owenia fusiformis undergoes equal spiral cleavage where the first quartet of animal micromeres are slightly larger than the vegetal macromeres. Cleavage results in a coeloblastula approximately 5 h post-fertilization (hpf) at 19 °C. Gastrulation occurs via invagination and completes 4 h later, with putative mesodermal precursors and the chaetoblasts appearing 10 hpf at the dorso-posterior side. Soon after, at 11 hpf, the apical tuft emerges, followed by the first neurons (as revealed by the expression of elav1 and synaptotagmin-1) in the apical organ and the prototroch by 13 hpf. Muscles connecting the chaetal sac to various larval tissues develop around 18 hpf and by the time the mitraria is fully formed at 22 hpf, there are FMRFamide+ neurons in the apical organ and prototroch, the latter forming a prototrochal ring. As the mitraria feeds, it grows in size and the prototroch expands through active proliferation. The larva becomes competent after ~ 3 weeks post-fertilization at 15 °C, when a conspicuous juvenile rudiment has formed ventrally. CONCLUSIONS Owenia fusiformis embryogenesis is similar to that of other equal spiral cleaving annelids, supporting that equal cleavage is associated with the formation of a coeloblastula, gastrulation via invagination, and a feeding trochophore-like larva in Annelida. The nervous system of the mitraria larva forms earlier and is more elaborated than previously recognized and develops from anterior to posterior, which is likely an ancestral condition to Annelida. Altogether, our study identifies the major developmental events during O. fusiformis ontogeny, defining a conceptual framework for future investigations.
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Affiliation(s)
| | - Océane Seudre
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Kero Guynes
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - José María Martín-Durán
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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32
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Proteomic identification of select protein variants of the SNARE interactome associated with cognitive reserve in a large community sample. Acta Neuropathol 2021; 141:755-770. [PMID: 33646358 DOI: 10.1007/s00401-021-02282-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Age-related neuropathologies progressively impair cognitive abilities by damaging synaptic function. We aimed to identify key components within the presynaptic SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) machinery associated with cognitive performance and estimate their potential contribution to brain reserve in old age. We used targeted SRM proteomics to quantify amounts of 60 peptides, encoded in 30 different genes, in postmortem specimens of the prefrontal cortex from 1209 participants of two aging studies, with available antemortem cognitive evaluations and postmortem neuropathologic assessments. We found that select (but not all) proteoforms are strongly associated with cognitive function and the burden of Alzheimer's disease (AD) pathology. Specifically, greater abundance of STX1A (but not other syntaxins), SYT12, full-length SNAP25, and the GABAergic STXBP1 variant were robustly associated with better cognitive performance. By contrast, greater abundance of other presynaptic proteins (e.g., STXBP5 or tomosyn, STX7, or SYN2) showed a negative influence on cognition. Regression models adjusting for demographic and pathologic variables showed that altered levels of these protein species explained 7.7% additional between-subject variance in cognition (more than any individual age-related neuropathology in the model), suggesting that these molecules constitute key elements of brain reserve. Network analyses indicated that those peptides associated with brain reserve, and closest to the SNARE fusogenic activity, showed greater centrality measures and were better connected in the network. Validation assays confirmed the selective loss of the STX1A (but not STX1B) isoform in cognitively impaired cases. In rodent and human brains, STX1A was selectively located at glutamatergic terminals. However, in AD brains, STX1A was redistributed adjacent to neuritic pathology, and markedly expressed in astrocytes. Our study provides strong evidence, indicating that select presynaptic proteins are key in maintaining brain reserve. Compromised ability to sustain expression levels of these proteins may trigger synaptic dysfunction and concomitant cognitive impairment.
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33
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CAPS1 is involved in hippocampal synaptic plasticity and hippocampus-associated learning. Sci Rep 2021; 11:8656. [PMID: 33883618 PMCID: PMC8060421 DOI: 10.1038/s41598-021-88009-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/07/2021] [Indexed: 12/14/2022] Open
Abstract
Calcium-dependent activator protein for secretion 1 (CAPS1) is a key molecule in vesicular exocytosis, probably in the priming step. However, CAPS1's role in synaptic plasticity and brain function is elusive. Herein, we showed that synaptic plasticity and learning behavior were impaired in forebrain and/or hippocampus-specific Caps1 conditional knockout (cKO) mice by means of molecular, physiological, and behavioral analyses. Neonatal Caps1 cKO mice showed a decrease in the number of docked vesicles in the hippocampal CA3 region, with no detectable changes in the distribution of other major exocytosis-related molecules. Additionally, long-term potentiation (LTP) was partially and severely impaired in the CA1 and CA3 regions, respectively. CA1 LTP was reinforced by repeated high-frequency stimuli, whereas CA3 LTP was completely abolished. Accordingly, hippocampus-associated learning was severely impaired in adeno-associated virus (AAV) infection-mediated postnatal Caps1 cKO mice. Collectively, our findings suggest that CAPS1 is a key protein involved in the cellular mechanisms underlying hippocampal synaptic release and plasticity, which is crucial for hippocampus-associated learning.
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Wei C, Pohorille A. Fast bilayer-micelle fusion mediated by hydrophobic dipeptides. Biophys J 2021; 120:2330-2342. [PMID: 33887225 DOI: 10.1016/j.bpj.2021.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/15/2021] [Accepted: 04/02/2021] [Indexed: 11/30/2022] Open
Abstract
To understand the transition from inanimate matter to life, we studied a process that directly couples simple metabolism to evolution via natural selection, demonstrated experimentally by Adamala and Szostak. In this process, dipeptides synthesized inside precursors of cells promote absorption of fatty acid micelles to vesicles, inducing their preferential growth and division at the expense of other vesicles. The process is explained on the basis of coarse-grained molecular dynamics simulations, each extending for tens of microseconds, carried out to model fusion between a micelle and a membrane, both made of fatty acids in the absence and presence of hydrophobic dipeptides. In all systems with dipeptides, but not in their absence, fusion events were observed. They involve the formation of a stalk made by hydrophobic chains from the micelle and the membrane, similar to that postulated for vesicle-vesicle fusion. The emergence of a stalk is facilitated by transient clusters of dipeptides, side chains of which form hydrophobic patches at the membrane surface. Committor probability calculations indicate that the size of a patch is a suitable reaction coordinate and allows for identifying the transition state for fusion. Free-energy barrier to fusion is greatly reduced in the presence of dipeptides to only 4-5 kcal/mol, depending on the hydrophobicity of side chains. The mechanism of mediated fusion, which is expected to apply to other small peptides and hydrophobic molecules, provides a robust means by which a nascent metabolism can confer evolutionary advantage to precursors of cells.
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Affiliation(s)
- Chenyu Wei
- NASA Ames Research Center, Moffett Field, California; Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California
| | - Andrew Pohorille
- NASA Ames Research Center, Moffett Field, California; Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California.
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Function of Drosophila Synaptotagmins in membrane trafficking at synapses. Cell Mol Life Sci 2021; 78:4335-4364. [PMID: 33619613 PMCID: PMC8164606 DOI: 10.1007/s00018-021-03788-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/29/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022]
Abstract
The Synaptotagmin (SYT) family of proteins play key roles in regulating membrane trafficking at neuronal synapses. Using both Ca2+-dependent and Ca2+-independent interactions, several SYT isoforms participate in synchronous and asynchronous fusion of synaptic vesicles (SVs) while preventing spontaneous release that occurs in the absence of stimulation. Changes in the function or abundance of the SYT1 and SYT7 isoforms alter the number and route by which SVs fuse at nerve terminals. Several SYT family members also regulate trafficking of other subcellular organelles at synapses, including dense core vesicles (DCV), exosomes, and postsynaptic vesicles. Although SYTs are linked to trafficking of multiple classes of synaptic membrane compartments, how and when they interact with lipids, the SNARE machinery and other release effectors are still being elucidated. Given mutations in the SYT family cause disorders in both the central and peripheral nervous system in humans, ongoing efforts are defining how these proteins regulate vesicle trafficking within distinct neuronal compartments. Here, we review the Drosophila SYT family and examine their role in synaptic communication. Studies in this invertebrate model have revealed key similarities and several differences with the predicted activity of their mammalian counterparts. In addition, we highlight the remaining areas of uncertainty in the field and describe outstanding questions on how the SYT family regulates membrane trafficking at nerve terminals.
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Gao T, Zhang Z, Yang Y, Zhang H, Li N, Liu B. Impact of RIM-BPs in neuronal vesicles release. Brain Res Bull 2021; 170:129-136. [PMID: 33581313 DOI: 10.1016/j.brainresbull.2021.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Accurate signal transmission between neurons is accomplished by vesicle release with high spatiotemporal resolution in the central nervous system. The vesicle release occurs mainly in the active zone (AZ), a unique area on the presynaptic membrane. Many structural proteins expressed in the AZ connect with other proteins nearby. They can also regulate the precise release of vesicles through protein-protein interactions. RIM-binding proteins (RIM-BPs) are one of the essential proteins in the AZ. This review summarizes the structures and functions of three subtypes of RIM-BPs, including the interaction between RIM-BPs and other proteins such as Bassoon and voltage-gated calcium channel, their significance in stabilizing the AZ structure in the presynaptic region and collecting ion channels, and ultimately regulating the fusion and release of neuronal vesicles.
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Affiliation(s)
- Tianyu Gao
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Zhengyao Zhang
- School of Life and Pharmaceutical Sciences, Panjin Campus of Dalian University of Technology, Panjin, 124221, China
| | - Yunong Yang
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Hangyu Zhang
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China
| | - Na Li
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China.
| | - Bo Liu
- School of Biomedical Engineering, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian, 116024, China.
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Orock A, Logan S, Deak F. Age-Related Cognitive Impairment: Role of Reduced Synaptobrevin-2 Levels in Deficits of Memory and Synaptic Plasticity. J Gerontol A Biol Sci Med Sci 2021; 75:1624-1632. [PMID: 30649208 DOI: 10.1093/gerona/glz013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Indexed: 01/02/2023] Open
Abstract
Cognitive impairment in the aging population is quickly becoming a health care priority, for which currently no disease-modifying treatment is available. Multiple domains of cognition decline with age even in the absence of neurodegenerative diseases. The cellular and molecular changes leading to cognitive decline with age remain elusive. Synaptobrevin-2 (Syb2), the major vesicular SNAP receptor protein, highly expressed in the cerebral cortex and hippocampus, is essential for synaptic transmission. We have analyzed Syb2 protein levels in mice and found a decrease with age. To investigate the functional consequences of lower Syb2 expression, we have used adult Syb2 heterozygous mice (Syb2+/-) with reduced Syb2 levels. This allowed us to mimic the age-related decrease of Syb2 in the brain in order to selectively test its effects on learning and memory. Our results show that Syb2+/- animals have impaired learning and memory skills and they perform worse with age in the radial arm water maze assay. Syb2+/- hippocampal neurons have reduced synaptic plasticity with reduced release probability and impaired long-term potentiation in the CA1 region. Syb2+/- neurons also have lower vesicular release rates when compared to WT controls. These results indicate that reduced Syb2 expression with age is sufficient to cause cognitive impairment.
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Affiliation(s)
- Albert Orock
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Sreemathi Logan
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Ferenc Deak
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City
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de la Riva-Carrasco R, Perez-Pandolfo S, Suárez Freire S, Romero NM, Bhujabal Z, Johansen T, Wappner P, Melani M. The immunophilin Zonda controls regulated exocytosis in endocrine and exocrine tissues. Traffic 2021; 22:111-122. [PMID: 33336828 DOI: 10.1111/tra.12777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 11/30/2022]
Abstract
Exocytosis is a fundamental process in physiology, that ensures communication between cells, organs and even organisms. Hormones, neuropeptides and antibodies, among other cargoes are packed in exocytic vesicles that need to reach and fuse with the plasma membrane to release their content to the extracellular milieu. Hundreds of proteins participate in this process and several others in its regulation. We report here a novel component of the exocytic machinery, the Drosophila transmembrane immunophilin Zonda (Zda), previously found to participate in autophagy. Zda is highly expressed in secretory tissues, and regulates exocytosis in at least three of them: the ring gland, insulin-producing cells and the salivary gland. Using the salivary gland as a model system, we found that Zda is required at final steps of the exocytic process for fusion of secretory granules to the plasma membrane. In a genetic screen we identified the small GTPase RalA as a crucial regulator of secretory granule exocytosis that is required, similarly to Zda, for fusion between the secretory granule and the plasma membrane.
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Affiliation(s)
| | - Sebastián Perez-Pandolfo
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina
| | - Sofía Suárez Freire
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina
| | - Nuria M Romero
- Université Côte d'Azur, INRA, CNRS, Institut Sophia Agrobiotech, Sophia Antipolis, France
| | - Zambarlal Bhujabal
- Molecular Cancer Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Terje Johansen
- Molecular Cancer Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Pablo Wappner
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mariana Melani
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Quintas M, Neto JL, Sequeiros J, Sousa A, Pereira-Monteiro J, Lemos C, Alonso I. Going Deep into Synaptic Vesicle Machinery Genes and Migraine Susceptibility - A Case-Control Association Study. Headache 2020; 60:2152-2165. [PMID: 32979221 DOI: 10.1111/head.13957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE A number of observations, including among our study population, have implicated variants in the syntaxin-1A, a component of the synaptic vesicles, in migraine susceptibility. Therefore, we hypothesize that variants in other components of the vesicle machinery are involved in migraine. BACKGROUND Migraine is a common and complex neurologic disorder that affects approximately 15-18% of the general population. The exact cause of migraine is unknown; however, genetic studies have made possible substantial progress toward the identification of underlying molecular pathways. Neurotransmitters have been for long considered to have a key role in migraine pathophysiology; so we investigated common variants in genes involved in the synaptic vesicle machinery and their impact in migraine susceptibility. METHODS We performed a case-control study comprising 188 unrelated patients with headache and 286 healthy controls in a population from the north of Portugal. Benefiting from the presence of linkage disequilibrium, we selected and genotyped 119 tagging single-nucleotide polymorphisms in 18 genes. RESULTS We found significant associations between single-nucleotide variants and migraine in 7 genes, SYN1, SYN2, SNAP25, VAMP2, STXBP1, STXBP5, and UNC13A, either conferring an increased risk or protection of migraine. Due to SYN1 X-chromosomal location, we performed the statistical analysis separated by gender and, in the female group, the C allele of rs5906435 increased the risk for migraine susceptibility (P = .021; OR = 1.69; 95% CI: 1.21-2.34). In contrast, the TT genotype of the same variant emerged as a potential protective factor (P = .003; OR = 0.45; 95% CI: 0.27-0.74). The SYN2 analysis supported the rs3773364's G allele (P = .014) as a risk factor for migraine, and although not statistically significant after correction, the AG genotype (P = .006; OR = 1.86; 95% CI: 1.20-2.90) reinforced the allelic findings. Additionally, we found the SNAP25-rs363039's CT genotype (P = .001; OR = 2.14; 95% CI: 1.36-3.34), the STXBP5-rs1765028's T allele (P = .041; OR = 1.46; 95% CI: 1.13-1.90), and the UNC13B-rs7851161's TT genotype (P = .001; OR = 2.14; 95% CI: 1.36-3.34) as statistically significant risk factors for migraine liability. VAMP2-rs1150's G allele revealed a risk association to migraine, not statistically significant after correction (P = .068). Additionally, we found haplotypes in SYN1, SYN2, STXBP1, and UNC13B to be associated with migraine. CONCLUSIONS Overall, this study provides a new insight into migraine liability, identifying possible starting points for functional studies.
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Affiliation(s)
- Marlene Quintas
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - João Luís Neto
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jorge Sequeiros
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Alda Sousa
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - José Pereira-Monteiro
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Carolina Lemos
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Isabel Alonso
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Matta SM, Moore Z, Walker FR, Hill-Yardin EL, Crack PJ. An altered glial phenotype in the NL3 R451C mouse model of autism. Sci Rep 2020; 10:14492. [PMID: 32879325 PMCID: PMC7468159 DOI: 10.1038/s41598-020-71171-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 06/26/2020] [Indexed: 12/26/2022] Open
Abstract
Autism Spectrum Disorder (ASD; autism) is a neurodevelopmental disorder characterised by deficits in social communication, and restricted and/or repetitive behaviours. While the precise pathophysiologies are unclear, increasing evidence supports a role for dysregulated neuroinflammation in the brain with potential effects on synapse function. Here, we studied characteristics of microglia and astrocytes in the Neuroligin-3 (NL3R451C) mouse model of autism since these cell types are involved in regulating both immune and synapse function. We observed increased microglial density in the dentate gyrus (DG) of NL3R451C mice without morphological differences. In contrast, WT and NL3R451C mice had similar astrocyte density but astrocyte branch length, the number of branch points, as well as cell radius and area were reduced in the DG of NL3R451C mice. Because retraction of astrocytic processes has been linked to altered synaptic transmission and dendrite formation, we assessed for regional changes in pre- and postsynaptic protein expression in the cortex, striatum and cerebellum in NL3R451C mice. NL3R451C mice showed increased striatal postsynaptic density 95 (PSD-95) protein levels and decreased cortical expression of synaptosomal-associated protein 25 (SNAP-25). These changes could contribute to dysregulated neurotransmission and cognition deficits previously reported in these mice.
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Affiliation(s)
- Samantha M Matta
- Department of Pharmacology and Therapeutics, The University of Melbourne, Grattan St, Parkville, VIC, Australia.,School of Health & Biomedical Sciences, RMIT University, 225-245 Clements Drive, Bundoora, VIC, Australia
| | - Zachery Moore
- Department of Pharmacology and Therapeutics, The University of Melbourne, Grattan St, Parkville, VIC, Australia
| | - Frederick Rohan Walker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, University Drive, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Locked Bag 1000, New Lambton, NSW, Australia
| | - Elisa L Hill-Yardin
- School of Health & Biomedical Sciences, RMIT University, 225-245 Clements Drive, Bundoora, VIC, Australia.,Department of Physiology, The University of Melbourne, Grattan St, Parkville, VIC, Australia
| | - Peter J Crack
- Department of Pharmacology and Therapeutics, The University of Melbourne, Grattan St, Parkville, VIC, Australia.
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Munc18-1 induces conformational changes of syntaxin-1 in multiple intermediates for SNARE assembly. Sci Rep 2020; 10:11623. [PMID: 32669573 PMCID: PMC7363831 DOI: 10.1038/s41598-020-68476-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/25/2020] [Indexed: 01/16/2023] Open
Abstract
In neuronal exocytosis, SNARE assembly into a stable four-helix bundle drives membrane fusion. Previous studies have revealed that the SM protein Munc18-1 plays a critical role for precise SNARE assembly with the help of Munc13-1, but the underlying mechanism remains unclear. Here, we used single-molecule FRET assays with a nanodisc membrane reconstitution system to investigate the conformational dynamics of SNARE/Munc18-1 complexes in multiple intermediate steps towards the SNARE complex. We found that single Munc18-1 proteins induce the closed conformation of syntaxin-1 not only in the free syntaxin-1 but also in the t-SNARE (syntaxin-1/SNAP-25) complex. These results implicate that Munc18-1 may act as a gatekeeper for both binary and ternary SNARE complex formation by locking the syntaxin-1 in a cleft of Munc18-1. Furthermore, the kinetic analysis of the opening/closing transition reveals that the closed syntaxin-1 in the syntaxin-1/SNAP-25/Munc18-1 complex is less stable than that in the closed syntaxin-1/Munc18-1 complex, which is manifested by the infrequent closing transition, indicating that the conformational equilibrium of the ternary complex is biased toward the open conformation of syntaxin-1 compared with the binary complex.
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Eubanks HB, Lavoie EG, Goree J, Kamykowski JA, Gokden N, Fausther M, Dranoff JA. Reduction in SNAP-23 Alters Microfilament Organization in Myofibrobastic Hepatic Stellate Cells. Gene Expr 2020; 20:25-37. [PMID: 31757226 PMCID: PMC7284106 DOI: 10.3727/105221619x15742818049365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Hepatic stellate cells (HSC) are critical effector cells of liver fibrosis. In the injured liver, HSC differentiate into a myofibrobastic phenotype. A critical feature distinguishing myofibroblastic from quiescent HSC is cytoskeletal reorganization. Soluble NSF attachment receptor (SNARE) proteins are important in trafficking of newly synthesized proteins to the plasma membrane for release into the extracellular environment. The goals of this project were to determine the expression of specific SNARE proteins in myofibroblastic HSC and to test whether their alteration changed the HSC phenotype in vitro and progression of liver fibrosis in vivo. We found that HSC lack the t-SNARE protein, SNAP-25, but express a homologous protein, SNAP-23. Downregulation of SNAP-23 in HSC induced reduction in polymerization and disorganization of the actin cytoskeleton associated with loss of cell movement. In contrast, reduction in SNAP-23 in mice by monogenic deletion delayed but did not prevent progression of liver fibrosis to cirrhosis. Taken together, these findings suggest that SNAP-23 is an important regular of actin dynamics in myofibroblastic HSC, but that the role of SNAP-23 in the progression of liver fibrosis in vivo is unclear.
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Affiliation(s)
- Haleigh B. Eubanks
- *Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Elise G. Lavoie
- *Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jessica Goree
- *Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jeffrey A. Kamykowski
- †Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Neriman Gokden
- ‡Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Michel Fausther
- *Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jonathan A. Dranoff
- *Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Huang F, Duan R, Zhou Z, Vázquez-González M, Xia F, Willner I. Near-infrared light-activated membrane fusion for cancer cell therapeutic applications. Chem Sci 2020; 11:5592-5600. [PMID: 32874503 PMCID: PMC7441577 DOI: 10.1039/d0sc00863j] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/07/2020] [Indexed: 12/15/2022] Open
Abstract
The spatiotemporal stimulation of liposome-liposome or liposome-membrane fusion processes attracts growing interest as a means to mimic cell-cell interactions in nature and for using these processes for biomedical applications. We report the use of o-nitrobenzyl phosphate functionalized-cholesterol tethered nucleic acid-modified liposomes as functional photoresponsive units for inducing, by NIR-irradiation, spatiotemporal liposome-liposome or liposome-membrane fusion processes. The liposomes are loaded with upconversion nanoparticles (UCNPs) and their NIR irradiation (λ = 980 nm) yields luminescence at λ = 365 nm, providing a localized light-source to deprotect the o-nitrobenzyl phosphate groups and resulting in the fragmentation of the nucleic acid structures. In one system, the NIR-triggered fusion of two liposomes, L1 and L2, is exemplified. Liposome L1 is loaded with UCNPs and Tb3+ ions, and the liposome boundary is functionalized with a cholesterol-tethered, o-nitrobenzyl phosphate caged hairpin nucleic acid structure. Liposome L2 is loaded with 2,6-pyridinedicarboxylic acid, DPA, and its boundary is modified with a cholesterol-tethered nucleic acid, complementary to a part of the caged hairpin, associated with L1. NIR-irradiation of the L1/L2 mixture resulted in the photocleavage of the hairpin structure, associated with L1, and the resulting fragmented nucleic acid associated with L1 hybridized with the nucleic acid linked to L2, leading to the fusion of the two liposomes. The fusion process was followed by dynamic light scattering, and by monitoring the fluorescence of the Tb3+-DPA complex generated upon the fusion of the liposomes and their exchange of contents (fusion efficiency 30%). In a second system, the fusion of the liposomes L1, loaded with UCNPs and doxorubicin (DOX), with HeLa cancer cells functionalized with nucleic acid tethers, complementary to the hairpin units associated with the boundary of L1, and linked to the MUC-1 receptor sites associated with the HeLa cells, through a MUC-1 aptamer unit is exemplified. The effect of DOX-loaded L1/HeLa cell fusion on the cytotoxicity towards HeLa cells is addressed. The NIR UCNP-stimulated cleavage of the o-nitrobenzyl phosphate caged hairpin units associated with L1 leads to the fragmentation of the hairpin units and the resulting nucleic acid tethers hybridize with the nucleic acid-modified HeLa cells, resulting in the liposome-HeLa cell fusion and the release of DOX into the HeLa cells. Selective spatiotemporal cytotoxicity towards HeLa cells is demonstrated (ca. 40% cell killing within two days). The study presents a comprehensive stepwise set of experiments directed towards the development of NIR-driven liposome-liposome or liposome-membrane fusion processes.
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Affiliation(s)
- Fujian Huang
- Engineering Research Center of Nano-Geomaterials of Ministry of Education , Faculty of Materials Science and Chemistry , China University of Geosciences , Wuhan 430074 , China . ;
| | - Ruilin Duan
- Engineering Research Center of Nano-Geomaterials of Ministry of Education , Faculty of Materials Science and Chemistry , China University of Geosciences , Wuhan 430074 , China . ;
| | - Zhixin Zhou
- Institute of Chemistry , Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel .
| | - Margarita Vázquez-González
- Institute of Chemistry , Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel .
| | - Fan Xia
- Engineering Research Center of Nano-Geomaterials of Ministry of Education , Faculty of Materials Science and Chemistry , China University of Geosciences , Wuhan 430074 , China . ;
| | - Itamar Willner
- Institute of Chemistry , Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel .
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Bittner T, Wittwer C, Hauke S, Wohlwend D, Mundinger S, Dutta AK, Bezold D, Dürr T, Friedrich T, Schultz C, Jessen HJ. Photolysis of Caged Inositol Pyrophosphate InsP 8 Directly Modulates Intracellular Ca 2+ Oscillations and Controls C2AB Domain Localization. J Am Chem Soc 2020; 142:10606-10611. [PMID: 32459478 DOI: 10.1021/jacs.0c01697] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inositol pyrophosphates constitute a family of hyperphosphorylated signaling molecules involved in the regulation of glucose uptake and insulin sensitivity. While our understanding of the biological roles of inositol heptaphosphates (PP-InsP5) has greatly improved, the functions of the inositol octaphosphates ((PP)2-InsP4) have remained unclear. Here we present the synthesis of two enantiomeric cell-permeant and photocaged (PP)2-InsP4 derivatives and apply them to study the functions in living β-cells. Photorelease of the naturally occurring isomer 1,5-(PP)2-InsP4 led to an immediate and concentration-dependent reduction of intracellular calcium oscillations, while other caged inositol pyrophosphates (3,5-(PP)2-InsP4, 5-PP-InsP5, 1-PP-InsP5, 3-PP-InsP5) showed no immediate effect. Furthermore, uncaging of 1,5-(PP)2-InsP4 but not 3,5-(PP)2-InsP4 induced translocation of the C2AB domain of granuphilin from the plasma membrane to the cytosol. Granuphilin is involved in membrane docking of secretory vesicles. This suggests that 1,5-(PP)2-InsP4 impacts β-cell activity by regulating granule localization and/or priming and calcium signaling in concert.
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Affiliation(s)
- Tamara Bittner
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Christopher Wittwer
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Sebastian Hauke
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Daniel Wohlwend
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Stephan Mundinger
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Amit K Dutta
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Dominik Bezold
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Tobias Dürr
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Thorsten Friedrich
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Carsten Schultz
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University (OHSU), Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
| | - Henning J Jessen
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, 79104 Freiburg i.B., Germany.,Freiburg Research Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Albertstrasse 19, 79104 Freiburg i.B., Germany
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Akimov SA, Molotkovsky RJ, Kuzmin PI, Galimzyanov TR, Batishchev OV. Continuum Models of Membrane Fusion: Evolution of the Theory. Int J Mol Sci 2020; 21:E3875. [PMID: 32485905 PMCID: PMC7312925 DOI: 10.3390/ijms21113875] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/24/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022] Open
Abstract
Starting from fertilization, through tissue growth, hormone secretion, synaptic transmission, and sometimes morbid events of carcinogenesis and viral infections, membrane fusion regulates the whole life of high organisms. Despite that, a lot of fusion processes still lack well-established models and even a list of main actors. A merger of membranes requires their topological rearrangements controlled by elastic properties of a lipid bilayer. That is why continuum models based on theories of membrane elasticity are actively applied for the construction of physical models of membrane fusion. Started from the view on the membrane as a structureless film with postulated geometry of fusion intermediates, they developed along with experimental and computational techniques to a powerful tool for prediction of the whole process with molecular accuracy. In the present review, focusing on fusion processes occurring in eukaryotic cells, we scrutinize the history of these models, their evolution and complication, as well as open questions and remaining theoretical problems. We show that modern approaches in this field allow continuum models of membrane fusion to stand shoulder to shoulder with molecular dynamics simulations, and provide the deepest understanding of this process in multiple biological systems.
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Affiliation(s)
- Sergey A. Akimov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (R.J.M.); (P.I.K.); (T.R.G.); (O.V.B.)
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46
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Park SJ, Park H, Kim MG, Zhang S, Park SE, Kim S, Chung C. Inositol Pyrophosphate Metabolism Regulates Presynaptic Vesicle Cycling at Central Synapses. iScience 2020; 23:101000. [PMID: 32252022 PMCID: PMC7132149 DOI: 10.1016/j.isci.2020.101000] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 02/17/2020] [Accepted: 03/18/2020] [Indexed: 11/27/2022] Open
Abstract
The coordination of synaptic vesicle exocytosis and endocytosis supports neurotransmitter release from presynaptic terminals. Although inositol pyrophosphates, such as 5-diphosphoinositol pentakisphosphate (5-IP7), are versatile signaling metabolites in many biological events, physiological actions of 5-IP7 on synaptic membrane vesicle trafficking remain unclear. Here, we investigated the role of 5-IP7 in synaptic transmission in hippocampal brain slices from inositol hexakisphosphate kinase 1 (Ip6k1)-knockout mice. We found that presynaptic release probability was significantly increased in Ip6k1-knockout neurons, implying enhanced activity-dependent synaptic vesicle exocytosis. Expression of wild-type but not catalytically inactive IP6K1 in the Ip6k1-knockout hippocampus restored the altered presynaptic release probability. Moreover, Ip6k1-knockout neurons were insensitive to folimycin, a vacuolar ATPase inhibitor, and dynasore, a dynamin inhibitor, suggesting marked impairment in synaptic endocytosis during exocytosis. Our findings collectively establish that IP6K1 and its product, 5-IP7, act as key physiological determinants for inhibition of presynaptic vesicle exocytosis and stimulation of endocytosis at central synapses.
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Affiliation(s)
- Seung Ju Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Hoyong Park
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea
| | - Min-Gyu Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Seungjae Zhang
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea
| | - Seung Eun Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Seyun Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; KAIST Institute for the BioCentury, KAIST, Daejeon 34141, Korea.
| | - ChiHye Chung
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea.
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47
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Choi JE, Kim J, Kim J. Capturing activated neurons and synapses. Neurosci Res 2020; 152:25-34. [DOI: 10.1016/j.neures.2019.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/12/2022]
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48
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Chen F, Yin Y, Chua BT, Li P. CIDE family proteins control lipid homeostasis and the development of metabolic diseases. Traffic 2019; 21:94-105. [PMID: 31746121 DOI: 10.1111/tra.12717] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/03/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Feng‐Jung Chen
- Institute of Metabolism and Integrative Biology, the Human Phenome InstituteFudan University, and Zhongshan Hospital of Fudan University Shanghai China
| | - Yesheng Yin
- Institute of Metabolism and Integrative Biology, the Human Phenome InstituteFudan University, and Zhongshan Hospital of Fudan University Shanghai China
| | - Boon Tin Chua
- Institute of Metabolism and Integrative Biology, the Human Phenome InstituteFudan University, and Zhongshan Hospital of Fudan University Shanghai China
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua‐Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life SciencesTsinghua University Beijing China
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Vanuytsel S, Carniello J, Wallace MI. Artificial Signal Transduction across Membranes. Chembiochem 2019; 20:2569-2580. [DOI: 10.1002/cbic.201900254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/09/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Steven Vanuytsel
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Joanne Carniello
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Mark Ian Wallace
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
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Verardo D, Agnarsson B, Zhdanov VP, Höök F, Linke H. Single-Molecule Detection with Lightguiding Nanowires: Determination of Protein Concentration and Diffusivity in Supported Lipid Bilayers. NANO LETTERS 2019; 19:6182-6191. [PMID: 31369284 DOI: 10.1021/acs.nanolett.9b02226] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Determining the surface concentration and diffusivity of cell-membrane-bound molecules is central to the understanding of numerous important biochemical processes taking place at cell membranes. Here we use the high aspect ratio and lightguiding properties of semiconductor nanowires (NWs) to detect the presence of single freely diffusing proteins bound to a lipid bilayer covering the NW surface. Simultaneous observation of light-emission dynamics of hundreds of individual NWs occurring on the time scale of only a few seconds is interpreted using analytical models and employed to determine both surface concentration and diffusivity of cholera toxin subunit B (CTxB) bound to GM1 gangliosides in supported lipid bilayer (SLB) at surface concentrations down to below one CTxB per μm2. In particular, a decrease in diffusivity was observed with increasing GM1 content in the SLB, suggesting increasing multivalent binding of CTxB to GM1. The lightguiding capability of the NWs makes the method compatible with conventional epifluorescence microscopy, and it is shown to work well for both photostable and photosensitive dyes. These features make the concept an interesting complement to existing techniques for studying the diffusivity of low-abundance cell-membrane-bound molecules, expanding the rapidly growing use of semiconductor NWs in various bioanalytical sensor applications and live cell studies.
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Affiliation(s)
- Damiano Verardo
- NanoLund and Solid State Physics , Lund University , 22100 Lund , Sweden
| | - Björn Agnarsson
- Department of Physics , Chalmers University of Technology , 41296 Göteborg , Sweden
| | - Vladimir P Zhdanov
- Department of Physics , Chalmers University of Technology , 41296 Göteborg , Sweden
- Boreskov Institute of Catalysis , Russian Academy of Sciences , Novosibirsk 630090 , Russia
| | - Fredrik Höök
- Department of Physics , Chalmers University of Technology , 41296 Göteborg , Sweden
| | - Heiner Linke
- NanoLund and Solid State Physics , Lund University , 22100 Lund , Sweden
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