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Asmerian H, Alberts J, Sanetra AM, Diaz AJ, Silm K. Role of adaptor protein complexes in generating functionally distinct synaptic vesicle pools. J Physiol 2024. [PMID: 39034608 DOI: 10.1113/jp286179] [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: 04/24/2024] [Accepted: 07/05/2024] [Indexed: 07/23/2024] Open
Abstract
The synaptic vesicle (SV) cycle ensures the release of neurotransmitters and the replenishment of SVs to sustain neuronal activity. Multiple endocytosis and sorting pathways contribute to the recapture of the SV membrane and proteins after fusion. Adaptor protein (AP) complexes are among the critical components of the SV retrieval machinery. The canonical clathrin adaptor AP2 ensures the replenishment of most SVs across many neuronal populations. An alternative AP1/AP3-dependent process mediates the formation of a subset of SVs that differ from AP2 vesicles in molecular composition and respond preferentially during higher frequency firing. Furthermore, recent studies show that vesicular transporters for different neurotransmitters depend to a different extent on the AP3 pathway and this affects the release properties of the respective neurotransmitters. This review focuses on the current understanding of the AP-dependent molecular and functional diversity among SVs. We also discuss the contribution of these pathways to the regulation of neurotransmitter release across neuronal populations.
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Affiliation(s)
- Hrach Asmerian
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jacob Alberts
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Anna M Sanetra
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alexia J Diaz
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Katlin Silm
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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2
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Caputo M, Ivanova D, Chasserot-Golaz S, Doussau F, Haeberlé AM, Royer C, Ozkan S, Ecard J, Vitale N, Cousin MA, Tóth P, Gasman S, Ory S. Phospholipid Scramblase 1 Controls Efficient Neurotransmission and Synaptic Vesicle Retrieval at Cerebellar Synapses. J Neurosci 2024; 44:e0042242024. [PMID: 38839301 PMCID: PMC11223464 DOI: 10.1523/jneurosci.0042-24.2024] [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: 01/08/2024] [Revised: 04/23/2024] [Accepted: 04/28/2024] [Indexed: 06/07/2024] Open
Abstract
Phospholipids (PLs) are asymmetrically distributed at the plasma membrane. This asymmetric lipid distribution is transiently altered during calcium-regulated exocytosis, but the impact of this transient remodeling on presynaptic function is currently unknown. As phospholipid scramblase 1 (PLSCR1) randomizes PL distribution between the two leaflets of the plasma membrane in response to calcium activation, we set out to determine its role in neurotransmission. We report here that PLSCR1 is expressed in cerebellar granule cells (GrCs) and that PLSCR1-dependent phosphatidylserine egress occurred at synapses in response to neuron stimulation. Synaptic transmission is impaired at GrC Plscr1 -/- synapses, and both PS egress and synaptic vesicle (SV) endocytosis are inhibited in Plscr1 -/- cultured neurons from male and female mice, demonstrating that PLSCR1 controls PL asymmetry remodeling and SV retrieval following neurotransmitter release. Altogether, our data reveal a novel key role for PLSCR1 in SV recycling and provide the first evidence that PL scrambling at the plasma membrane is a prerequisite for optimal presynaptic performance.
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Affiliation(s)
- Margherita Caputo
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Daniela Ivanova
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Sylvette Chasserot-Golaz
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Frédéric Doussau
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Anne-Marie Haeberlé
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Cathy Royer
- Plateforme Imagerie In Vitro, Centre National de la Recherche Scientifique UPS3256, Strasbourg F-67000, France
| | - Sebahat Ozkan
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Jason Ecard
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Petra Tóth
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
| | - Stéphane Ory
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg F-67000, France
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3
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Wei L, Guo X, Haimov E, Obashi K, Lee SH, Shin W, Sun M, Chan CY, Sheng J, Zhang Z, Mohseni A, Ghosh Dastidar S, Wu XS, Wang X, Han S, Arpino G, Shi B, Molakarimi M, Matthias J, Wurm CA, Gan L, Taraska JW, Kozlov MM, Wu LG. Clathrin mediates membrane fission and budding by constricting membrane pores. Cell Discov 2024; 10:62. [PMID: 38862506 PMCID: PMC11166961 DOI: 10.1038/s41421-024-00677-w] [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: 08/24/2023] [Accepted: 04/04/2024] [Indexed: 06/13/2024] Open
Abstract
Membrane budding, which underlies fundamental processes like endocytosis, intracellular trafficking, and viral infection, is thought to involve membrane coat-forming proteins, including the most observed clathrin, to form Ω-shape profiles and helix-forming proteins like dynamin to constrict Ω-profiles' pores and thus mediate fission. Challenging this fundamental concept, we report that polymerized clathrin is required for Ω-profiles' pore closure and that clathrin around Ω-profiles' base/pore region mediates pore constriction/closure in neuroendocrine chromaffin cells. Mathematical modeling suggests that clathrin polymerization at Ω-profiles' base/pore region generates forces from its intrinsically curved shape to constrict/close the pore. This new fission function may exert broader impacts than clathrin's well-known coat-forming function during clathrin (coat)-dependent endocytosis, because it underlies not only clathrin (coat)-dependent endocytosis, but also diverse endocytic modes, including ultrafast, fast, slow, bulk, and overshoot endocytosis previously considered clathrin (coat)-independent in chromaffin cells. It mediates kiss-and-run fusion (fusion pore closure) previously considered bona fide clathrin-independent, and limits the vesicular content release rate. Furthermore, analogous to results in chromaffin cells, we found that clathrin is essential for fast and slow endocytosis at hippocampal synapses where clathrin was previously considered dispensable, suggesting clathrin in mediating synaptic vesicle endocytosis and fission. These results suggest that clathrin and likely other intrinsically curved coat proteins are a new class of fission proteins underlying vesicle budding and fusion. The half-a-century concept and studies that attribute vesicle-coat contents' function to Ω-profile formation and classify budding as coat-protein (e.g., clathrin)-dependent or -independent may need to be re-defined and re-examined by considering clathrin's pivotal role in pore constriction/closure.
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Affiliation(s)
- Lisi Wei
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Xiaoli Guo
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Ehud Haimov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel
| | - Kazuki Obashi
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Sung Hoon Lee
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Chung-Ang University, Seoul, Republic of Korea
| | - Wonchul Shin
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Min Sun
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Chung Yu Chan
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Jiansong Sheng
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- 900 Clopper Rd, Suite, 130, Gaithersburg, MD, USA
| | - Zhen Zhang
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Center of Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Ammar Mohseni
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | - Xin-Sheng Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Xin Wang
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Sue Han
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Gianvito Arpino
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
- Emme 3 Srl - Via Luigi Meraviglia, 31 - 20020, Lainate, MI, Italy
| | - Bo Shi
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Maryam Molakarimi
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | | | - Lin Gan
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
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Guiberson NGL, Black LS, Haller JE, Brukner A, Abramov D, Ahmad S, Xie YX, Sharma M, Burré J. Disease-linked mutations in Munc18-1 deplete synaptic Doc2. Brain 2024; 147:2185-2202. [PMID: 38242640 PMCID: PMC11146428 DOI: 10.1093/brain/awae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/20/2023] [Accepted: 01/09/2024] [Indexed: 01/21/2024] Open
Abstract
Heterozygous de novo mutations in the neuronal protein Munc18-1/STXBP1 cause syndromic neurological symptoms, including severe epilepsy, intellectual disability, developmental delay, ataxia and tremor, summarized as STXBP1 encephalopathies. Although haploinsufficiency is the prevailing disease mechanism, it remains unclear how the reduction in Munc18-1 levels causes synaptic dysfunction in disease as well as how haploinsufficiency alone can account for the significant heterogeneity among patients in terms of the presence, onset and severity of different symptoms. Using biochemical and cell biological readouts on mouse brains, cultured mouse neurons and heterologous cells, we found that the synaptic Munc18-1 interactors Doc2A and Doc2B are unstable in the absence of Munc18-1 and aggregate in the presence of disease-causing Munc18-1 mutants. In haploinsufficiency-mimicking heterozygous knockout neurons, we found a reduction in Doc2A/B levels that is further aggravated by the presence of the disease-causing Munc18-1 mutation G544D as well as an impairment in Doc2A/B synaptic targeting in both genotypes. We also demonstrated that overexpression of Doc2A/B partially rescues synaptic dysfunction in heterozygous knockout neurons but not heterozygous knockout neurons expressing G544D Munc18-1. Our data demonstrate that STXBP1 encephalopathies are not only characterized by the dysfunction of Munc18-1 but also by the dysfunction of the Munc18-1 binding partners Doc2A and Doc2B, and that this dysfunction is exacerbated by the presence of a Munc18-1 missense mutant. These findings may offer a novel explanation for the significant heterogeneity in symptoms observed among STXBP1 encephalopathy patients.
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Affiliation(s)
- Noah Guy Lewis Guiberson
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Luca S Black
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jillian E Haller
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Aniv Brukner
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Debra Abramov
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Saad Ahmad
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Yan Xin Xie
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Manu Sharma
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jacqueline Burré
- Helen and Robert Appel Alzheimer’s Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
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5
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Song P, Peng W, Sauve V, Fakih R, Xie Z, Ysselstein D, Krainc T, Wong YC, Mencacci NE, Savas JN, Surmeier DJ, Gehring K, Krainc D. Parkinson's disease-linked parkin mutation disrupts recycling of synaptic vesicles in human dopaminergic neurons. Neuron 2023; 111:3775-3788.e7. [PMID: 37716354 DOI: 10.1016/j.neuron.2023.08.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/08/2023] [Accepted: 08/17/2023] [Indexed: 09/18/2023]
Abstract
Parkin-mediated mitophagy has been studied extensively, but whether mutations in parkin contribute to Parkinson's disease pathogenesis through alternative mechanisms remains unexplored. Using patient-derived dopaminergic neurons, we found that phosphorylation of parkin by Ca2+/calmodulin-dependent protein kinase 2 (CaMK2) at Ser9 leads to activation of parkin in a neuronal-activity-dependent manner. Activated parkin ubiquitinates synaptojanin-1, facilitating its interaction with endophilin A1 and synaptic vesicle recycling. Neurons from PD patients with mutant parkin displayed defective recycling of synaptic vesicles, leading to accumulation of toxic oxidized dopamine that was attenuated by boosting endophilin A1 expression. Notably, combined heterozygous parkin and homozygous PTEN-induced kinase 1 (PINK1) mutations led to earlier disease onset compared with homozygous mutant PINK1 alone, further underscoring a PINK1-independent role for parkin in contributing to disease. Thus, this study identifies a pathway for selective activation of parkin at human dopaminergic synapses and highlights the importance of this mechanism in the pathogenesis of Parkinson's disease.
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Affiliation(s)
- Pingping Song
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Wesley Peng
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Veronique Sauve
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Rayan Fakih
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Zhong Xie
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Daniel Ysselstein
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Talia Krainc
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Yvette C Wong
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Niccolò E Mencacci
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jeffrey N Savas
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - D James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Kalle Gehring
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Dimitri Krainc
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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6
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Shen Y, Wen Y, Sposini S, Vishwanath AA, Abdelfattah AS, Schreiter ER, Lemieux MJ, de Juan-Sanz J, Perrais D, Campbell RE. Rational Engineering of an Improved Genetically Encoded pH Sensor Based on Superecliptic pHluorin. ACS Sens 2023; 8:3014-3022. [PMID: 37481776 DOI: 10.1021/acssensors.3c00484] [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] [Indexed: 07/25/2023]
Abstract
Genetically encoded pH sensors based on fluorescent proteins are valuable tools for the imaging of cellular events that are associated with pH changes, such as exocytosis and endocytosis. Superecliptic pHluorin (SEP) is a pH-sensitive green fluorescent protein (GFP) variant widely used for such applications. Here, we report the rational design, development, structure, and applications of Lime, an improved SEP variant with higher fluorescence brightness and greater pH sensitivity. The X-ray crystal structure of Lime supports the mechanistic rationale that guided the introduction of beneficial mutations. Lime provides substantial improvements relative to SEP for imaging of endocytosis and exocytosis. Furthermore, Lime and its variants are advantageous for a broader range of applications including the detection of synaptic release and neuronal voltage changes.
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Affiliation(s)
- Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yurong Wen
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
- Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Silvia Sposini
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, Bordeaux 33076, France
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London SW7 2BX, United Kingdom
| | - Anjali Amrapali Vishwanath
- Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, APHP, Häpital de la Pitié Salpêtrière, Sorbonne Université, 75013 Paris, France
| | - Ahmed S Abdelfattah
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virgina 20147, United States
- Department of Neuroscience, Brown University, Providence, Rhode Island 02906, United States
| | - Eric R Schreiter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virgina 20147, United States
| | - M Joanne Lemieux
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Jaime de Juan-Sanz
- Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, APHP, Häpital de la Pitié Salpêtrière, Sorbonne Université, 75013 Paris, France
| | - David Perrais
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, Bordeaux 33076, France
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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7
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Kontaxi C, Ivanova D, Davenport EC, Kind PC, Cousin MA. Epilepsy-Related CDKL5 Deficiency Slows Synaptic Vesicle Endocytosis in Central Nerve Terminals. J Neurosci 2023; 43:2002-2020. [PMID: 36759195 PMCID: PMC10027047 DOI: 10.1523/jneurosci.1537-22.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/20/2022] [Accepted: 01/09/2023] [Indexed: 02/11/2023] Open
Abstract
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a severe early-onset epileptic encephalopathy resulting mainly from de novo mutations in the X-linked CDKL5 gene. To determine whether loss of presynaptic CDKL5 function contributes to CDD, we examined synaptic vesicle (SV) recycling in primary hippocampal neurons generated from Cdkl5 knockout rat males. Using a genetically encoded reporter, we revealed that CDKL5 is selectively required for efficient SV endocytosis. We showed that CDKL5 kinase activity is both necessary and sufficient for optimal SV endocytosis, since kinase-inactive mutations failed to correct endocytosis in Cdkl5 knockout neurons, whereas the isolated CDKL5 kinase domain fully restored SV endocytosis kinetics. Finally, we demonstrated that CDKL5-mediated phosphorylation of amphiphysin 1, a putative presynaptic target, is not required for CDKL5-dependent control of SV endocytosis. Overall, our findings reveal a key presynaptic role for CDKL5 kinase activity and enhance our insight into how its dysfunction may culminate in CDD.SIGNIFICANCE STATEMENT Loss of cyclin-dependent kinase like 5 (CDKL5) function is a leading cause of monogenic childhood epileptic encephalopathy. However, information regarding its biological role is scarce. In this study, we reveal a selective presynaptic role for CDKL5 in synaptic vesicle endocytosis and that its protein kinase activity is both necessary and sufficient for this role. The isolated protein kinase domain is sufficient to correct this loss of function, which may facilitate future gene therapy strategies if presynaptic dysfunction is proven to be central to the disorder. It also reveals that a CDKL5-specific substrate is located at the presynapse, the phosphorylation of which is required for optimal SV endocytosis.
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Affiliation(s)
- Christiana Kontaxi
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
| | - Daniela Ivanova
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, United Kingdom
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8
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Krishnan S, Klingauf J. The readily retrievable pool of synaptic vesicles. Biol Chem 2023; 404:385-397. [PMID: 36867726 DOI: 10.1515/hsz-2022-0298] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/16/2023] [Indexed: 03/05/2023]
Abstract
In the CNS communication between neurons occurs at synapses by secretion of neurotransmitter via exocytosis of synaptic vesicles (SVs) at the active zone. Given the limited number of SVs in presynaptic boutons a fast and efficient recycling of exocytosed membrane and proteins by triggered compensatory endocytosis is required to maintain neurotransmission. Thus, pre-synapses feature a unique tight coupling of exo- and endocytosis in time and space resulting in the reformation of SVs with uniform morphology and well-defined molecular composition. This rapid response requires early stages of endocytosis at the peri-active zone to be well choreographed to ensure reformation of SVs with high fidelity. The pre-synapse can address this challenge by a specialized membrane microcompartment, where a pre-sorted and pre-assembled readily retrievable pool (RRetP) of endocytic membrane patches is formed, consisting of the vesicle cargo, presumably bound within a nucleated Clathrin and adaptor complex. This review considers evidence for the RRetP microcompartment to be the primary organizer of presynaptic triggered compensatory endocytosis.
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Affiliation(s)
- Sai Krishnan
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch Strasse 31, D-48149, Münster, Germany
| | - Jürgen Klingauf
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch Strasse 31, D-48149, Münster, Germany.,Center for Soft Nanoscience, Busso-Peus Strasse 10, D-48149, Münster, Germany
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9
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Watson ET, Pauers MM, Seibert MJ, Vevea JD, Chapman ER. Synaptic vesicle proteins are selectively delivered to axons in mammalian neurons. eLife 2023; 12:e82568. [PMID: 36729040 PMCID: PMC9894587 DOI: 10.7554/elife.82568] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/11/2023] [Indexed: 02/03/2023] Open
Abstract
Neurotransmitter-filled synaptic vesicles (SVs) mediate synaptic transmission and are a hallmark specialization in neuronal axons. Yet, how SV proteins are sorted to presynaptic nerve terminals remains the subject of debate. The leading model posits that these proteins are randomly trafficked throughout neurons and are selectively retained in presynaptic boutons. Here, we used the RUSH (retention using selective hooks) system, in conjunction with HaloTag labeling approaches, to study the egress of two distinct transmembrane SV proteins, synaptotagmin 1 and synaptobrevin 2, from the soma of mature cultured rat and mouse neurons. For these studies, the SV reporter constructs were expressed at carefully controlled, very low levels. In sharp contrast to the selective retention model, both proteins selectively and specifically entered axons with minimal entry into dendrites. However, even moderate overexpression resulted in the spillover of SV proteins into dendrites, potentially explaining the origin of previous non-polarized transport models, revealing the limited, saturable nature of the direct axonal trafficking pathway. Moreover, we observed that SV constituents were first delivered to the presynaptic plasma membrane before incorporation into SVs. These experiments reveal a new-found membrane trafficking pathway, for SV proteins, in classically polarized mammalian neurons and provide a glimpse at the first steps of SV biogenesis.
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Affiliation(s)
- Emma T Watson
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Howard Hughes Medical InstituteMadisonUnited States
| | - Michaela M Pauers
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Howard Hughes Medical InstituteMadisonUnited States
| | - Michael J Seibert
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Howard Hughes Medical InstituteMadisonUnited States
| | - Jason D Vevea
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Howard Hughes Medical InstituteMadisonUnited States
| | - Edwin R Chapman
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Howard Hughes Medical InstituteMadisonUnited States
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10
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Wu XS, Wu LG. Multiple Modes of Fusion and Retrieval at the Calyx of Held Synapse. ADVANCES IN NEUROBIOLOGY 2023; 33:43-62. [PMID: 37615863 DOI: 10.1007/978-3-031-34229-5_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Neurotransmitter in vesicles is released through a fusion pore when vesicles fuse with the plasma membrane. Subsequent retrieval of the fused vesicle membrane is the key step in recycling exocytosed vesicles. Application of advanced electrophysiological techniques to a large nerve terminal, the calyx of Held, has led to recordings of endocytosis, individual vesicle fusion and retrieval, and the kinetics of the fusion pore opening process and the fission pore closure process. These studies have revealed three kinetically different forms of endocytosis-rapid, slow, and bulk-and two forms of fusion-full collapse and kiss-and-run. Calcium influx triggers all kinetically distinguishable forms of endocytosis at calyces by activation of calmodulin/calcineurin signaling pathway and protein kinase C, which may dephosphorylate and phosphorylate endocytic proteins. Polymerized actin may provide mechanical forces to bend the membrane, forming membrane pits, the precursor for generating vesicles. These research advancements are reviewed in this chapter.
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Affiliation(s)
- Xin-Sheng Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
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11
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Lamanna J, Ferro M, Spadini S, Malgaroli A. Exploiting the molecular diversity of the synapse to investigate neuronal communication: A guide through the current toolkit. Eur J Neurosci 2022; 56:6141-6161. [PMID: 36239030 PMCID: PMC10100385 DOI: 10.1111/ejn.15848] [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: 03/24/2022] [Revised: 07/15/2022] [Accepted: 10/10/2022] [Indexed: 12/29/2022]
Abstract
Chemical synapses are tiny and overcrowded environments, deeply embedded inside brain tissue and enriched with thousands of protein species. Many efforts have been devoted to developing custom approaches for evaluating and modifying synaptic activity. Most of these methods are based on the engineering of one or more synaptic protein scaffolds used to target active moieties to the synaptic compartment or to manipulate synaptic functioning. In this review, we summarize the most recent methodological advances and provide a description of the involved proteins as well as the operation principle. Furthermore, we highlight their advantages and limitations in relation to studies of synaptic transmission in vitro and in vivo. Concerning the labelling methods, the most important challenge is how to extend the available approaches to the in vivo setting. On the other hand, for those methods that allow manipulation of synaptic function, this limit has been overcome using optogenetic approaches that can be more easily applied to the living brain. Finally, future applications of these methods to neuroscience, as well as new potential routes for development, are discussed.
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Affiliation(s)
- Jacopo Lamanna
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Milan, Italy.,Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy
| | - Mattia Ferro
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Milan, Italy.,Department of Psychology, Sigmund Freud University, Milan, Italy
| | - Sara Spadini
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Milan, Italy.,Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy
| | - Antonio Malgaroli
- Center for Behavioral Neuroscience and Communication (BNC), Vita-Salute San Raffaele University, Milan, Italy.,Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Turro, IRCCS Ospedale San Raffaele, Milan, Italy
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12
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Lam M, Takeo K, Almeida RG, Cooper MH, Wu K, Iyer M, Kantarci H, Zuchero JB. CNS myelination requires VAMP2/3-mediated membrane expansion in oligodendrocytes. Nat Commun 2022; 13:5583. [PMID: 36151203 PMCID: PMC9508103 DOI: 10.1038/s41467-022-33200-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/07/2022] [Indexed: 11/08/2022] Open
Abstract
Myelin is required for rapid nerve signaling and is emerging as a key driver of CNS plasticity and disease. How myelin is built and remodeled remains a fundamental question of neurobiology. Central to myelination is the ability of oligodendrocytes to add vast amounts of new cell membrane, expanding their surface areas by many thousand-fold. However, how oligodendrocytes add new membrane to build or remodel myelin is not fully understood. Here, we show that CNS myelin membrane addition requires exocytosis mediated by the vesicular SNARE proteins VAMP2/3. Genetic inactivation of VAMP2/3 in myelinating oligodendrocytes caused severe hypomyelination and premature death without overt loss of oligodendrocytes. Through live imaging, we discovered that VAMP2/3-mediated exocytosis drives membrane expansion within myelin sheaths to initiate wrapping and power sheath elongation. In conjunction with membrane expansion, mass spectrometry of oligodendrocyte surface proteins revealed that VAMP2/3 incorporates axon-myelin adhesion proteins that are collectively required to form nodes of Ranvier. Together, our results demonstrate that VAMP2/3-mediated membrane expansion in oligodendrocytes is indispensable for myelin formation, uncovering a cellular pathway that could sculpt myelination patterns in response to activity-dependent signals or be therapeutically targeted to promote regeneration in disease.
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Affiliation(s)
- Mable Lam
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Koji Takeo
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
- Pharmaceutical Research Laboratories, Toray Industries, Inc., Kamakura, Kanagawa, Japan
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Madeline H Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Kathryn Wu
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Husniye Kantarci
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
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13
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Ballin M, Griep W, Patel M, Karl M, Mentrup T, Rivera‐Monroy J, Foo B, Schwappach B, Schröder B. The intramembrane proteases
SPPL2a
and
SPPL2b
regulate the homeostasis of selected
SNARE
proteins. FEBS J 2022; 290:2320-2337. [PMID: 36047592 DOI: 10.1111/febs.16610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 08/30/2022] [Indexed: 01/15/2023]
Abstract
Signal peptide peptidase (SPP) and SPP-like (SPPL) aspartyl intramembrane proteases are known to contribute to sequential processing of type II-oriented membrane proteins referred to as regulated intramembrane proteolysis. The ER-resident family members SPP and SPPL2c were shown to also cleave tail-anchored proteins, including selected SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins facilitating membrane fusion events. Here, we analysed whether the related SPPL2a and SPPL2b proteases, which localise to the endocytic or late secretory pathway, are also able to process SNARE proteins. Therefore, we screened 18 SNARE proteins for cleavage by SPPL2a and SPPL2b based on cellular co-expression assays, of which the proteins VAMP1, VAMP2, VAMP3 and VAMP4 were processed by SPPL2a/b demonstrating the capability of these two proteases to proteolyse tail-anchored proteins. Cleavage of the four SNARE proteins was scrutinised at the endogenous level upon SPPL2a/b inhibition in different cell lines as well as by analysing VAMP1-4 levels in tissues and primary cells of SPPL2a/b double-deficient (dKO) mice. Loss of SPPL2a/b activity resulted in an accumulation of VAMP1-4 in a cell type- and tissue-dependent manner, identifying these proteins as SPPL2a/b substrates validated in vivo. Therefore, we propose that SPPL2a/b control cellular levels of VAMP1-4 by initiating the degradation of these proteins, which might impact cellular trafficking.
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Affiliation(s)
- Moritz Ballin
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Wolfram Griep
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Mehul Patel
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Martin Karl
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Jhon Rivera‐Monroy
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Brian Foo
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Blanche Schwappach
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
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14
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Shi B, Wu XS, Cordero NP, Moreira SL, Wu LG. Light and electron microscopic imaging of synaptic vesicle endocytosis at mouse hippocampal cultures. STAR Protoc 2022; 3:101495. [PMID: 35776639 PMCID: PMC9249854 DOI: 10.1016/j.xpro.2022.101495] [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: 02/25/2022] [Revised: 04/29/2022] [Accepted: 06/06/2022] [Indexed: 11/05/2022] Open
Abstract
Following the release of neurotransmitters at synaptic vesicles via exocytosis, endocytosis is initiated to retrieve vesicles that have fused with the plasma membrane of nerve terminals and recycle them, thus sustaining synaptic transmission. Here, we describe imaging-based protocols for quantitative measurements of endocytosis at cultured synapses. These protocols include (1) primary culture of mouse hippocampal neurons, (2) studying endocytosis at neurons transfected with a pH-sensitive synaptophysin-pHluorin2× using fluorescent microscopy, and (3) imaging endocytosis at fixed neurons with electron microscopy. For complete details on the use and execution of this protocol, please refer to Wu et al. (2016) and Wu et al. (2021). Detailed protocol for primary culture and transfection of mouse hippocampal neurons Light microscopy and analysis of endocytosis in cultured neurons Electron microscopy and analysis of vesicle and endosome formation
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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15
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Shin W, Zucker B, Kundu N, Lee SH, Shi B, Chan CY, Guo X, Harrison JT, Turechek JM, Hinshaw JE, Kozlov MM, Wu LG. Molecular mechanics underlying flat-to-round membrane budding in live secretory cells. Nat Commun 2022; 13:3697. [PMID: 35760780 PMCID: PMC9237132 DOI: 10.1038/s41467-022-31286-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 06/10/2022] [Indexed: 12/21/2022] Open
Abstract
Membrane budding entails forces to transform flat membrane into vesicles essential for cell survival. Accumulated studies have identified coat-proteins (e.g., clathrin) as potential budding factors. However, forces mediating many non-coated membrane buddings remain unclear. By visualizing proteins in mediating endocytic budding in live neuroendocrine cells, performing in vitro protein reconstitution and physical modeling, we discovered how non-coated-membrane budding is mediated: actin filaments and dynamin generate a pulling force transforming flat membrane into Λ-shape; subsequently, dynamin helices surround and constrict Λ-profile's base, transforming Λ- to Ω-profile, and then constrict Ω-profile's pore, converting Ω-profiles to vesicles. These mechanisms control budding speed, vesicle size and number, generating diverse endocytic modes differing in these parameters. Their impact is widespread beyond secretory cells, as the unexpectedly powerful functions of dynamin and actin, previously thought to mediate fission and overcome tension, respectively, may contribute to many dynamin/actin-dependent non-coated-membrane buddings, coated-membrane buddings, and other membrane remodeling processes.
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Affiliation(s)
- Wonchul Shin
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Ben Zucker
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Ramat Aviv, Israel
| | - Nidhi Kundu
- Structural Cell Biology Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Sung Hoon Lee
- Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Bo Shi
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Chung Yu Chan
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Xiaoli Guo
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Jonathan T Harrison
- Structural Cell Biology Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | | | - Jenny E Hinshaw
- Structural Cell Biology Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Ramat Aviv, Israel.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
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16
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Guo X, Han S, Wei L, Arpino G, Shin W, Wang X, Wu LG. Real-time visualization of exo- and endocytosis membrane dynamics with confocal and super-resolution microscopy. STAR Protoc 2022; 3:101404. [PMID: 35600934 PMCID: PMC9120246 DOI: 10.1016/j.xpro.2022.101404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Real-time confocal and super-resolution imaging reveals membrane dynamics of exo- and endocytosis, including hemi-fusion, fusion pore opening, expansion, constriction, closure (kiss-and-run), fused-vesicle shrinking (shrink fusion), and flat membrane transition to vesicles via intermediate Λ- and Ω-shape structures. Here, we describe a protocol for imaging these membrane dynamics, including primary culture of bovine adrenal chromaffin cells, fluorescent probe application, patch-clamp to deliver depolarization and evoke exo- and endocytosis, electron microscopy (EM), and real-time confocal and stimulated emission depletion (STED) microscopy. For complete details on the use and execution of this protocol, please refer to Zhao et al. (2016), Shin et al. (2018), and Shin et al. (2021).
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Affiliation(s)
- Xiaoli Guo
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Sue Han
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Lisi Wei
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Gianvito Arpino
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Wonchul Shin
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Xin Wang
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
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17
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Shi B, Jin YH, Wu LG. Dynamin 1 controls vesicle size and endocytosis at hippocampal synapses. Cell Calcium 2022; 103:102564. [PMID: 35220002 PMCID: PMC9009158 DOI: 10.1016/j.ceca.2022.102564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/27/2022] [Accepted: 02/15/2022] [Indexed: 11/16/2022]
Abstract
Following calcium-triggered vesicle exocytosis, endocytosis regenerates vesicles to maintain exocytosis and thus synaptic transmission, which underlies neuronal circuit activities. Although most molecules involved in endocytosis have been identified, it remains rather poorly understood how endocytic machinery regulates vesicle size. Vesicle size, together with the transmitter concentration inside the vesicle, determines the amount of transmitter the vesicle can release, the quantal size, that may control the strength of synaptic transmission. Here, we report that, surprisingly, knockout of the GTPase dynamin 1, the most abundant brain dynamin isoform known to catalyze fission of the membrane pit's neck (the last step of endocytosis), not only significantly slowed endocytosis but also increased the synaptic vesicle diameter by as much as ∼40-64% at cultured hippocampal synapses. Furthermore, dynamin 1 knockout increased the size of membrane pits, the precursor for endocytic vesicle formation. These results suggest an important function of dynamin other than its well-known fission function - control of vesicle size at the pit formation stage.
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Affiliation(s)
- Bo Shi
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States; Biological Sciences Graduate Program, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20740 United States
| | - Ying-Hui Jin
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States; Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Ave, Guangzhou 510515, China
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States.
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18
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An SJ, Stagi M, Gould TJ, Wu Y, Mlodzianoski M, Rivera-Molina F, Toomre D, Strittmatter SM, De Camilli P, Bewersdorf J, Zenisek D. Multimodal imaging of synaptic vesicles with a single probe. CELL REPORTS METHODS 2022; 2:100199. [PMID: 35497490 PMCID: PMC9046237 DOI: 10.1016/j.crmeth.2022.100199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/11/2022] [Accepted: 03/28/2022] [Indexed: 05/17/2023]
Abstract
A complete understanding of synaptic-vesicle recycling requires the use of multiple microscopy methods to obtain complementary information. However, many currently available probes are limited to a specific microscopy modality, which necessitates the use of multiple probes and labeling paradigms. Given the complexity of vesicle populations and recycling pathways, having new single-vesicle probes that could be used for multiple microscopy techniques would complement existing sets of tools for studying vesicle function. Here, we present a probe based on the membrane-binding C2 domain of cytosolic phospholipase A2 (cPLA2) that fulfills this need. By conjugating the C2 domain with different detectable tags, we demonstrate that a single, modular probe can allow synaptic vesicles to be imaged at multiple levels of spatial and temporal resolution. Moreover, as a general endocytic marker, the C2 domain may also be used to study membrane recycling in many cell types.
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Affiliation(s)
- Seong J. An
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Massimiliano Stagi
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool 69 3BX, UK
| | - Travis J. Gould
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Physics and Astronomy, Bates College, Lewiston, ME 04240, USA
| | - Yumei Wu
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Michael Mlodzianoski
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Stephen M. Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pietro De Camilli
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - David Zenisek
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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19
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Wang X, Sun M, Chan CY, Wu LG. Phospholipase A 2-based probes to study vesicle trafficking. CELL REPORTS METHODS 2022; 2:100206. [PMID: 35497501 PMCID: PMC9046444 DOI: 10.1016/j.crmeth.2022.100206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Vesicle exo- and endocytosis mediate important biological functions, including synaptic transmission. In this issue of Cell Reports Methods, Seong J. An et al. found that the fluorescently tagged C2 domain of phospholipase A2 binds to membrane phosphatidylcholine and thus labels vesicle membrane, allowing for super-resolution and electron microscopic visualization of vesicle trafficking.
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Affiliation(s)
- Xin Wang
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892, USA
| | - Min Sun
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892, USA
| | - Chung Yu Chan
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892, USA
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892, USA
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20
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Staudt A, Ratai O, Bouzouina A, Fecher-Trost C, Shaaban A, Bzeih H, Horn A, Shaib AH, Klose M, Flockerzi V, Lauterbach MA, Rettig J, Becherer U. Localization of the Priming Factors CAPS1 and CAPS2 in Mouse Sensory Neurons Is Determined by Their N-Termini. Front Mol Neurosci 2022; 15:674243. [PMID: 35493323 PMCID: PMC9049930 DOI: 10.3389/fnmol.2022.674243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Both paralogs of the calcium-dependent activator protein for secretion (CAPS) are required for exocytosis of synaptic vesicles (SVs) and large dense core vesicles (LDCVs). Despite approximately 80% sequence identity, CAPS1 and CAPS2 have distinct functions in promoting exocytosis of SVs and LDCVs in dorsal root ganglion (DRG) neurons. However, the molecular mechanisms underlying these differences remain enigmatic. In this study, we applied high- and super-resolution imaging techniques to systematically assess the subcellular localization of CAPS paralogs in DRG neurons deficient in both CAPS1 and CAPS2. CAPS1 was found to be more enriched at the synapses. Using – in-depth sequence analysis, we identified a unique CAPS1 N-terminal sequence, which we introduced into CAPS2. This CAPS1/2 chimera reproduced the pre-synaptic localization of CAPS1 and partially rescued synaptic transmission in neurons devoid of CAPS1 and CAPS2. Using immunoprecipitation combined with mass spectrometry, we identified CAPS1-specific interaction partners that could be responsible for its pre-synaptic enrichment. Taken together, these data suggest an important role of the CAPS1-N terminus in the localization of the protein at pre-synapses.
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Affiliation(s)
- Angelina Staudt
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Olga Ratai
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Aicha Bouzouina
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Claudia Fecher-Trost
- Department of Experimental and Clinical Pharmacology and Toxicology, Preclinical Center for Molecular Signaling (PZMS), Saarland University, Homburg, Germany
| | - Ahmed Shaaban
- Department of Neuroscience, University of Copenhagen, København, Denmark
| | - Hawraa Bzeih
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Alexander Horn
- Department of Organic Chemistry, Saarland University, Saarbrücken, Germany
| | - Ali H. Shaib
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
- Institute for Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Margarete Klose
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Veit Flockerzi
- Department of Experimental and Clinical Pharmacology and Toxicology, Preclinical Center for Molecular Signaling (PZMS), Saarland University, Homburg, Germany
| | - Marcel A. Lauterbach
- Department of Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Jens Rettig
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Ute Becherer
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
- *Correspondence: Ute Becherer,
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21
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Wu LG, Chan CY. Multiple Roles of Actin in Exo- and Endocytosis. Front Synaptic Neurosci 2022; 14:841704. [PMID: 35308832 PMCID: PMC8931529 DOI: 10.3389/fnsyn.2022.841704] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/11/2022] [Indexed: 11/20/2022] Open
Abstract
Cytoskeletal filamentous actin (F-actin) has long been considered a molecule that may regulate exo- and endocytosis. However, its exact roles remained elusive. Recent studies shed new light on many crucial roles of F-actin in regulating exo- and endocytosis. Here, this progress is reviewed from studies of secretory cells, particularly neurons and endocrine cells. These studies reveal that F-actin is involved in mediating all kinetically distinguishable forms of endocytosis, including ultrafast, fast, slow, bulk, and overshoot endocytosis, likely via membrane pit formation. F-actin promotes vesicle replenishment to the readily releasable pool most likely via active zone clearance, which may sustain synaptic transmission and overcome short-term depression of synaptic transmission during repetitive firing. By enhancing plasma membrane tension, F-actin promotes fusion pore expansion, vesicular content release, and a fusion mode called shrink fusion involving fusing vesicle shrinking. Not only F-actin, but also the F-actin assembly pathway, including ATP hydrolysis, N-WASH, and formin, are involved in mediating these roles of exo- and endocytosis. Neurological disorders, including spinocerebellar ataxia 13 caused by Kv3.3 channel mutation, may involve impairment of F-actin and its assembly pathway, leading in turn to impairment of exo- and endocytosis at synapses that may contribute to neurological disorders.
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Affiliation(s)
- Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States
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22
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Nabb AT, Bentley M. NgCAM and VAMP2 reveal that direct delivery and dendritic degradation maintain axonal polarity. Mol Biol Cell 2022; 33:ar3. [PMID: 34731031 PMCID: PMC8886818 DOI: 10.1091/mbc.e21-08-0425] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Neurons are polarized cells of extreme scale and compartmentalization. To fulfill their role in electrochemical signaling, axons must maintain a specific complement of membrane proteins. Despite being the subject of considerable attention, the trafficking pathway of axonal membrane proteins is not well understood. Two pathways, direct delivery and transcytosis, have been proposed. Previous studies reached contradictory conclusions about which of these mediates delivery of axonal membrane proteins to their destination, in part because they evaluated long-term distribution changes and not vesicle transport. We developed a novel strategy to selectively label vesicles in different trafficking pathways and determined the trafficking of two canonical axonal membrane proteins, neuron-glia cell adhesion molecule and vesicle-associated membrane protein-2. Results from detailed quantitative analyses of transporting vesicles differed substantially from previous studies and found that axonal membrane proteins overwhelmingly undergo direct delivery. Transcytosis plays only a minor role in axonal delivery of these proteins. In addition, we identified a novel pathway by which wayward axonal proteins that reach the dendritic plasma membrane are targeted to lysosomes. These results redefine how axonal proteins achieve their polarized distribution, a crucial requirement for elucidating the underlying molecular mechanisms.
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Affiliation(s)
- Alec T. Nabb
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Marvin Bentley
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180,*Address correspondence to: Marvin Bentley ()
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23
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Pulido C, Ryan TA. Synaptic vesicle pools are a major hidden resting metabolic burden of nerve terminals. SCIENCE ADVANCES 2021; 7:eabi9027. [PMID: 34860552 PMCID: PMC8641928 DOI: 10.1126/sciadv.abi9027] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 10/14/2021] [Indexed: 05/15/2023]
Abstract
The brain is a metabolically fragile organ as compromises in fuel availability rapidly degrade cognitive function. Nerve terminals are likely loci of this vulnerability as they do not store sufficient ATP molecules, needing to synthesize them during activity or suffer acute degradation in performance. The ability of on-demand ATP synthesis to satisfy activity-driven ATP hydrolysis will depend additionally on the magnitude of local resting metabolic processes. We show here that synaptic vesicle (SV) pools are a major source of presynaptic basal energy consumption. This basal metabolic processes arises from SV-resident V-ATPases compensating for a hidden resting H+ efflux from the SV lumen. We show that this steady-state H+ efflux (i) is mediated by vesicular neurotransmitter transporters, (ii) is independent of the SV cycle, (iii) accounts for up to 44% of the resting synaptic energy consumption, and (iv) contributes substantially to nerve terminal intolerance of fuel deprivation.
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Affiliation(s)
- Camila Pulido
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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24
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CDH2 mutation affecting N-cadherin function causes attention-deficit hyperactivity disorder in humans and mice. Nat Commun 2021; 12:6187. [PMID: 34702855 PMCID: PMC8548587 DOI: 10.1038/s41467-021-26426-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/29/2021] [Indexed: 11/20/2022] Open
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a common childhood-onset psychiatric disorder characterized by inattention, impulsivity and hyperactivity. ADHD exhibits substantial heritability, with rare monogenic variants contributing to its pathogenesis. Here we demonstrate familial ADHD caused by a missense mutation in CDH2, which encodes the adhesion protein N-cadherin, known to play a significant role in synaptogenesis; the mutation affects maturation of the protein. In line with the human phenotype, CRISPR/Cas9-mutated knock-in mice harboring the human mutation in the mouse ortholog recapitulated core behavioral features of hyperactivity. Symptoms were modified by methylphenidate, the most commonly prescribed therapeutic for ADHD. The mutated mice exhibited impaired presynaptic vesicle clustering, attenuated evoked transmitter release and decreased spontaneous release. Specific downstream molecular pathways were affected in both the ventral midbrain and prefrontal cortex, with reduced tyrosine hydroxylase expression and dopamine levels. We thus delineate roles for CDH2-related pathways in the pathophysiology of ADHD. Molecular mechanisms of attention-deficit hyperactivity disorder (ADHD) are not fully understood. Here the authors demonstrate a mutation in CDH2, encoding N-cadherin, that is associated with ADHD, and in a mouse model, delineate molecular electrophysiological characteristics associated with this mutation.
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25
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Zhang X, Liu Y, Hong X, Li X, Meshul CK, Moore C, Yang Y, Han Y, Li WG, Qi X, Lou H, Duan S, Xu TL, Tong X. NG2 glia-derived GABA release tunes inhibitory synapses and contributes to stress-induced anxiety. Nat Commun 2021; 12:5740. [PMID: 34593806 PMCID: PMC8484468 DOI: 10.1038/s41467-021-25956-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/09/2021] [Indexed: 11/08/2022] Open
Abstract
NG2 glia, also known as oligodendrocyte precursor cells (OPCs), play an important role in proliferation and give rise to myelinating oligodendrocytes during early brain development. In contrast to other glial cell types, the most intriguing aspect of NG2 glia is their ability to directly sense synaptic inputs from neurons. However, whether this synaptic interaction is bidirectional or unidirectional, or its physiological relevance has not yet been clarified. Here, we report that NG2 glia form synaptic complexes with hippocampal interneurons and that selective photostimulation of NG2 glia (expressing channelrhodopsin-2) functionally drives GABA release and enhances inhibitory synaptic transmission onto proximal interneurons in a microcircuit. The mechanism involves GAD67 biosynthesis and VAMP-2 containing vesicular exocytosis. Further, behavioral assays demonstrate that NG2 glia photoactivation triggers anxiety-like behavior in vivo and contributes to chronic social defeat stress.
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Affiliation(s)
- Xiao Zhang
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yao Liu
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoqi Hong
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xia Li
- Institute of Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Charles K Meshul
- Research Services, VA Medical Center, Portland, OR, USA
- Department of Behavioral Neuroscience and Pathology, Oregon Health & Science University, Portland, OR, USA
| | - Cynthia Moore
- Research Services, VA Medical Center, Portland, OR, USA
| | - Yabing Yang
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanfei Han
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei-Guang Li
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xin Qi
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huifang Lou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shumin Duan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Tian-Le Xu
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoping Tong
- Center for Brain Science, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai, China.
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26
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Bakr M, Jullié D, Krapivkina J, Paget-Blanc V, Bouit L, Petersen JD, Retailleau N, Breillat C, Herzog E, Choquet D, Perrais D. The vSNAREs VAMP2 and VAMP4 control recycling and intracellular sorting of post-synaptic receptors in neuronal dendrites. Cell Rep 2021; 36:109678. [PMID: 34496238 DOI: 10.1016/j.celrep.2021.109678] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 06/25/2021] [Accepted: 08/17/2021] [Indexed: 11/28/2022] Open
Abstract
The endosomal recycling system dynamically tunes synaptic strength, which underlies synaptic plasticity. Exocytosis is involved in the expression of long-term potentiation (LTP), as postsynaptic cleavage of the SNARE (soluble NSF-attachment protein receptor) protein VAMP2 by tetanus toxin blocks LTP. Moreover, induction of LTP increases the exocytosis of transferrin receptors (TfRs) and markers of recycling endosomes (REs), as well as post-synaptic AMPA type receptors (AMPARs). However, the interplay between AMPAR and TfR exocytosis remains unclear. Here, we identify VAMP4 as the vesicular SNARE that mediates most dendritic RE exocytosis. In contrast, VAMP2 plays a minor role in RE exocytosis. LTP induction increases the exocytosis of both VAMP2- and VAMP4-labeled organelles. Knock down (KD) of VAMP4 decreases TfR recycling but increases AMPAR recycling. Moreover, VAMP4 KD increases AMPAR-mediated synaptic transmission, which consequently occludes LTP expression. The opposing changes in AMPAR and TfR recycling upon VAMP4 KD reveal their sorting into separate endosomal populations.
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Affiliation(s)
- May Bakr
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Damien Jullié
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Julia Krapivkina
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Vincent Paget-Blanc
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Lou Bouit
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Jennifer D Petersen
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Natacha Retailleau
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Christelle Breillat
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Etienne Herzog
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Daniel Choquet
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France; Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, 33000 Bordeaux, France
| | - David Perrais
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France.
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27
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Wu XS, Subramanian S, Zhang Y, Shi B, Xia J, Li T, Guo X, El-Hassar L, Szigeti-Buck K, Henao-Mejia J, Flavell RA, Horvath TL, Jonas EA, Kaczmarek LK, Wu LG. Presynaptic Kv3 channels are required for fast and slow endocytosis of synaptic vesicles. Neuron 2021; 109:938-946.e5. [PMID: 33508244 PMCID: PMC7979485 DOI: 10.1016/j.neuron.2021.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/24/2020] [Accepted: 01/07/2021] [Indexed: 01/25/2023]
Abstract
Since their discovery decades ago, the primary physiological and pathological effects of potassium channels have been attributed to their ion conductance, which sets membrane potential and repolarizes action potentials. For example, Kv3 family channels regulate neurotransmitter release by repolarizing action potentials. Here we report a surprising but crucial function independent of potassium conductance: by organizing the F-actin cytoskeleton in mouse nerve terminals, the Kv3.3 protein facilitates slow endocytosis, rapid endocytosis, vesicle mobilization to the readily releasable pool, and recovery of synaptic depression during repetitive firing. A channel mutation that causes spinocerebellar ataxia inhibits endocytosis, vesicle mobilization, and synaptic transmission during repetitive firing by disrupting the ability of the channel to nucleate F-actin. These results unmask novel functions of potassium channels in endocytosis and vesicle mobilization crucial for sustaining synaptic transmission during repetitive firing. Potassium channel mutations that impair these "non-conducting" functions may thus contribute to generation of diverse neurological disorders.
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Affiliation(s)
- Xin-Sheng Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Shobana Subramanian
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Yalan Zhang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Bo Shi
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA; Biological Sciences Graduate Program, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20740, USA
| | - Jessica Xia
- Division of Biological Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Tiansheng Li
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Xiaoli Guo
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Lynda El-Hassar
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Klara Szigeti-Buck
- Department of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Jorge Henao-Mejia
- Department of Immunobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Department of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Elizabeth A Jonas
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA.
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28
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Lim TKY, Ruthazer ES. Microglial trogocytosis and the complement system regulate axonal pruning in vivo. eLife 2021; 10:e62167. [PMID: 33724186 PMCID: PMC7963485 DOI: 10.7554/elife.62167] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 02/28/2021] [Indexed: 12/14/2022] Open
Abstract
Partial phagocytosis-called trogocytosis-of axons by microglia has been documented in ex vivo preparations but has not been directly observed in vivo. The mechanisms that modulate microglial trogocytosis of axons and its function in neural circuit development remain poorly understood. Here, we directly observe axon trogocytosis by microglia in vivo in the developing Xenopus laevis retinotectal circuit. We show that microglia regulate pruning of retinal ganglion cell axons and are important for proper behavioral response to dark and bright looming stimuli. Using bioinformatics, we identify amphibian regulator of complement activation 3, a homolog of human CD46, as a neuronally expressed synapse-associated complement inhibitory molecule that inhibits trogocytosis and axonal pruning. Using a membrane-bound complement C3 fusion protein, we demonstrate that enhancing complement activity enhances axonal pruning. Our results support the model that microglia remodel axons via trogocytosis and that neurons can control this process through expression of complement inhibitory proteins.
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Affiliation(s)
- Tony KY Lim
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
| | - Edward S Ruthazer
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
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29
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Harper CB, Smillie KJ. Current molecular approaches to investigate pre-synaptic dysfunction. J Neurochem 2021; 157:107-129. [PMID: 33544872 DOI: 10.1111/jnc.15316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022]
Abstract
Over the course of the last few decades it has become clear that many neurodevelopmental and neurodegenerative disorders have a synaptic defect, which contributes to pathogenicity. A rise in new techniques, and in particular '-omics'-based methods providing large datasets, has led to an increase in potential proteins and pathways implicated in synaptic function and related disorders. Additionally, advancements in imaging techniques have led to the recent discovery of alternative modes of synaptic vesicle recycling. This has resulted in a lack of clarity over the precise role of different pathways in maintaining synaptic function and whether these new pathways are dysfunctional in neurodevelopmental and neurodegenerative disorders. A greater understanding of the molecular detail of pre-synaptic function in health and disease is key to targeting new proteins and pathways for novel treatments and the variety of new techniques currently available provides an ideal opportunity to investigate these functions. This review focuses on techniques to interrogate pre-synaptic function, concentrating mainly on synaptic vesicle recycling. It further examines techniques to determine the underlying molecular mechanism of pre-synaptic dysfunction and discusses methods to identify molecular targets, along with protein-protein interactions and cellular localization. In combination, these techniques will provide an expanding and more complete picture of pre-synaptic function. With the application of recent technological advances, we are able to resolve events with higher spatial and temporal resolution, leading research towards a greater understanding of dysfunction at the presynapse and the role it plays in pathogenicity.
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Affiliation(s)
- Callista B Harper
- Centre for Discovery Brain Sciences, University of Edinburgh, Scotland, UK
| | - Karen J Smillie
- Centre for Discovery Brain Sciences, University of Edinburgh, Scotland, UK
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30
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Abramov D, Guiberson NGL, Daab A, Na Y, Petsko GA, Sharma M, Burré J. Targeted stabilization of Munc18-1 function via pharmacological chaperones. EMBO Mol Med 2021; 13:e12354. [PMID: 33332765 PMCID: PMC7799358 DOI: 10.15252/emmm.202012354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 11/01/2020] [Accepted: 11/11/2020] [Indexed: 11/16/2022] Open
Abstract
Heterozygous de novo mutations in the neuronal protein Munc18-1 cause syndromic neurological symptoms, including severe epilepsy, intellectual disability, developmental delay, ataxia, and tremor. No disease-modifying therapy exists to treat these disorders, and while chemical chaperones have been shown to alleviate neuronal dysfunction caused by missense mutations in Munc18-1, their required high concentrations and potential toxicity necessitate a Munc18-1-targeted therapy. Munc18-1 is essential for neurotransmitter release, and mutations in Munc18-1 have been shown to cause neuronal dysfunction via aggregation and co-aggregation of the wild-type protein, reducing functional Munc18-1 levels well below hemizygous levels. Here, we identify two pharmacological chaperones via structure-based drug design, that bind to wild-type and mutant Munc18-1, and revert Munc18-1 aggregation and neuronal dysfunction in vitro and in vivo, providing the first targeted treatment strategy for these severe pediatric encephalopathies.
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Affiliation(s)
- Debra Abramov
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
| | - Noah Guy Lewis Guiberson
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
| | - Andrew Daab
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
- Present address:
University of BathBathUK
| | - Yoonmi Na
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
| | - Gregory A Petsko
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
- Present address:
Ann Romney Center for Neurologic DiseasesDepartment of NeurologyBrigham and Women’s Hospital and Harvard Medical SchoolBostonMA, USA
| | - Manu Sharma
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
| | - Jacqueline Burré
- Appel Institute for Alzheimer’s Disease ResearchBrain and Mind Research InstituteWeill Cornell MedicineNew YorkNYUSA
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31
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Measurements of Compensatory Endocytosis by Antibody Internalization and Quantification of Endocytic Vesicle Distribution in Adrenal Chromaffin Cells. Methods Mol Biol 2020. [PMID: 33222126 DOI: 10.1007/978-1-0716-1044-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Plasma membrane proteins are amenable to endocytosis assays since they are easily labeled by reagents applied in the extracellular medium. This has been widely exploited to study constitutive endocytosis or ligand-induced receptor endocytosis. Compensatory endocytosis is the mechanism by which components of secretory vesicles are retrieved after vesicle fusion with the plasma membrane in response to cell stimulation and a rise in intracellular calcium. Luminal membrane proteins from secretory vesicles are therefore transiently exposed at the plasma membrane. Here, we described an antibody-based method to monitor compensatory endocytosis in chromaffin cells and present an image-based analysis to quantify endocytic vesicles distribution.
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Woo DH, Hur YN, Jang MW, Justin Lee C, Park M. Inhibitors of synaptic vesicle exocytosis reduce surface expression of postsynaptic glutamate receptors. Anim Cells Syst (Seoul) 2020; 24:341-348. [PMID: 33456718 PMCID: PMC7781898 DOI: 10.1080/19768354.2020.1838607] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Bafilomycin A1, a vacuolar H+-ATPase inhibitor, and botulinum toxin B and tetanus toxin, both vesicle fusion inhibitors, are widely known exocytosis blockers that have been used to inhibit the presynaptic release of neurotransmitters. However, protein trafficking mechanisms, such as the insertion of postsynaptic receptors and astrocytic glutamate-releasing channels into the plasma membrane, also require exocytosis. In our previous study, exocytosis inhibitors reduced the surface expression of astrocytic glutamate-releasing channels. Here, we further investigated whether exocytosis inhibitors influence the surface expression of postsynaptic receptors. Using pH-sensitive superecliptic pHluorin (SEP)-tagged postsynaptic glutamate receptors, including GluA1, GluA2, GluN1, and GluN2A, we found that bafilomycin A1, botulinum toxin B, and/or tetanus toxin reduce the SEP fluorescence of SEP-GluA1, SEP-GluA2, SEP-GluN1, and SEP-GluN2A. These findings indicate that presynaptic vesicle exocytosis inhibitors also affect the postsynaptic trafficking machinery for surface expression. Finally, this study provides profound insights assembling presynaptic, postsynaptic and astrocytic viewpoints into the interpretation of the data obtained using these synaptic vesicle exocytosis inhibitors.
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Affiliation(s)
- Dong Ho Woo
- Drug Abuse Research Group, Research Center of Convergence Toxicology, Korea Institute of Toxicology, Daejeon, South Korea
| | - Young-Na Hur
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea.,Center for Cognition and Sociality, Cognitive Glioscience Group, Institute for Basic Science, Daejeon, Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Cognitive Glioscience Group, Institute for Basic Science, Daejeon, Korea
| | - Mikyoung Park
- Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Department of Neuroscience, Korea University of Science and Technology, Daejeon, South Korea
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Fusion Pore Formation Observed during SNARE-Mediated Vesicle Fusion with Pore-Spanning Membranes. Biophys J 2020; 119:151-161. [PMID: 32533941 DOI: 10.1016/j.bpj.2020.05.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 12/27/2022] Open
Abstract
Planar pore-spanning membranes (PSMs) have been shown to be a versatile tool to resolve elementary steps of the neuronal fusion process. However, in previous studies, we monitored only lipid mixing between fusing large unilamellar vesicles and PSMs and did not gather information about the formation of fusion pores. To address this important step of the fusion process, we entrapped sulforhodamine B at self-quenching concentrations into large unilamellar vesicles containing the v-SNARE synaptobrevin 2, which were docked and fused with lipid-labeled PSMs containing the t-SNARE acceptor complex ΔN49 prepared on gold-coated porous silicon substrates. By dual-color spinning disk fluorescence microscopy with a time resolution of ∼20 ms, we could unambiguously distinguish between bursting vesicles, which was only rarely observed (<0.01%), and fusion pore formation. From the time-resolved dual-color fluorescence time traces, we were able to identify different fusion pathways, including remaining three-dimensional postfusion structures with released content and transient openings and closings of the fusion pores. Our results on fusion pore formation and lipid diffusion from the PSM into the fusing vesicle let us conclude that the content release, i.e., fusion pore formation after the merger of the two lipid membranes occurs almost simultaneously.
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Kopach O, Zheng K, Rusakov DA. Optical monitoring of glutamate release at multiple synapses in situ detects changes following LTP induction. Mol Brain 2020; 13:39. [PMID: 32169106 PMCID: PMC7071671 DOI: 10.1186/s13041-020-00572-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/27/2020] [Indexed: 01/10/2023] Open
Abstract
Information processing and memory formation in the brain relies on release of the main excitatory neurotransmitter glutamate from presynaptic axonal specialisations. The classical Hebbian paradigm of synaptic memory, long-term potentiation (LTP) of transmission, has been widely associated with an increase in the postsynaptic receptor current. Whether and to what degree LTP induction also enhances presynaptic glutamate release has been the subject of debate. Here, we took advantage of the recently developed genetically encoded optical sensors of glutamate (iGluSnFR) to monitor its release at CA3-CA1 synapses in acute hippocampal slices, before and after the induction of LTP. We attempted to trace release events at multiple synapses simultaneously, by using two-photon excitation imaging in fast frame-scanning mode. We thus detected a significant increase in the average iGluSnFR signal during potentiation, which lasted for up to 90 min. This increase may reflect an increased amount of released glutamate or, alternatively, reduced glutamate binding to high-affinity glutamate transporters that compete with iGluSnFR.
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Affiliation(s)
- Olga Kopach
- Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Kaiyu Zheng
- Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Dmitri A Rusakov
- Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
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35
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Gowrisankaran S, Milosevic I. Regulation of synaptic vesicle acidification at the neuronal synapse. IUBMB Life 2020; 72:568-576. [DOI: 10.1002/iub.2235] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/29/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Sindhuja Gowrisankaran
- European Neuroscience Institute (ENI)A Joint Initiative of the University Medical Center Göttingen and the Max Planck Society Göttingen Germany
| | - Ira Milosevic
- European Neuroscience Institute (ENI)A Joint Initiative of the University Medical Center Göttingen and the Max Planck Society Göttingen Germany
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36
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Protein Kinase C and Calmodulin Serve As Calcium Sensors for Calcium-Stimulated Endocytosis at Synapses. J Neurosci 2019; 39:9478-9490. [PMID: 31628181 DOI: 10.1523/jneurosci.0182-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 08/27/2019] [Accepted: 10/07/2019] [Indexed: 02/04/2023] Open
Abstract
Calcium influx triggers and facilitates endocytosis, which recycles vesicles and thus sustains synaptic transmission. Despite decades of studies, the underlying calcium sensor remained not well understood. Here, we examined two calcium binding proteins, protein kinase C (PKC) and calmodulin. Whether PKC is involved in endocytosis was unclear; whether calmodulin acts as a calcium sensor for endocytosis was neither clear, although calmodulin involvement in endocytosis had been suggested. We generated PKC (α or β-isoform) and calmodulin (calmodulin 2 gene) knock-out mice of either sex and measured endocytosis with capacitance measurements, pHluorin imaging and electron microscopy. We found that these knock-outs inhibited slow (∼10-30 s) and rapid (<∼3 s) endocytosis at large calyx-type calyces, and inhibited slow endocytosis and bulk endocytosis (forming large endosome-like structures) at small conventional hippocampal synapses, suggesting the involvement of PKC and calmodulin in three most common forms of endocytosis-the slow, rapid and bulk endocytosis. Inhibition of slow endocytosis in PKC or calmodulin 2 knock-out hippocampal synapses was rescued by overexpressing wild-type PKC or calmodulin, but not calcium-binding-deficient PKC or calmodulin mutant, respectively, suggesting that calcium stimulates endocytosis by binding with its calcium sensor PKC and calmodulin. PKC and calmodulin 2 knock-out inhibited calcium-dependent vesicle mobilization to the readily releasable pool, suggesting that PKC and calmodulin may mediate calcium-dependent facilitation of vesicle mobilization. These findings shed light on the molecular signaling link among calcium, endocytosis and vesicle mobilization that are crucial in maintaining synaptic transmission and neuronal network activity.SIGNIFICANCE STATEMENT Vesicle fusion releases neurotransmitters to mediate synaptic transmission. To sustain synaptic transmission, fused vesicles must be retrieved via endocytosis. Accumulating evidence suggests that calcium influx triggers synaptic vesicle endocytosis. However, how calcium triggers endocytosis is not well understood. Using genetic tools together with capacitance measurements, optical imaging and electron microscopy, we identified two calcium sensors, including protein kinase C (α and β isoforms) and calmodulin, for the most commonly observed forms of endocytosis: slow, rapid, and bulk. We also found that these two proteins are involved in calcium-dependent vesicle mobilization to the readily releasable pool. These results provide the molecular signaling link among calcium, endocytosis, and vesicle mobilization that are essential in sustaining synaptic transmission and neuronal network activity.
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Henkel AW, Mouihate A, Welzel O. Differential Release of Exocytosis Marker Dyes Indicates Stimulation-Dependent Regulation of Synaptic Activity. Front Neurosci 2019; 13:1047. [PMID: 31632237 PMCID: PMC6783566 DOI: 10.3389/fnins.2019.01047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/18/2019] [Indexed: 02/05/2023] Open
Abstract
There is a general consensus that synaptic vesicular release by a full collapse process is the primary machinery of synaptic transmission. However, competing view suggests that synaptic vesicular release operates via a kiss-and-run mechanism. By monitoring the release dynamics of a synaptic vesicular marker, FM1-43 from individual synapses in hippocampal neurons, we found evidence that the release of synaptic vesicle was delayed by several seconds after the start of field stimulation. This phenomenon was associated with modified opening kinetics of fusion pores. Detailed analysis revealed that some synapses were completely inactive for a few seconds after stimulation, despite immediate calcium influx. This delay in vesicular release was modulated by various stimulation protocols and different frequencies, indicating an activity-dependent regulation mechanism for neurotransmitter exocytosis. Staurosporine, a drug known to induce “kiss-and-run” exocytosis, increased the proportion of delayed synapses as well as the delay duration, while fluoxetine acted contrarily. Besides being a serotonin reuptake inhibitor, it directly enhanced vesicle mobilization and reduced synaptic fatigue. Exocytosis was never delayed, when it was monitored with pH-sensitive probes, synaptopHlourin and αSyt-CypHerE5 antibody, indicating an instantaneous formation of a fusion pore that allowed rapid equilibration of vesicular lumenal pH but prevented FM1-43 release because of its slow dissociation from the inner vesicular membrane. Our observations suggest that synapses operate via a sequential “kiss-and-run” and “full-collapse” exocytosis mechanism. The initially narrow vesicular pore allows the equilibration of intravesicular pH which then progresses toward full fusion, causing FM1-43 release.
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Affiliation(s)
- Andreas W Henkel
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Oliver Welzel
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Erlangen, Germany
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38
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Kokotos AC, Harper CB, Marland JRK, Smillie KJ, Cousin MA, Gordon SL. Synaptophysin sustains presynaptic performance by preserving vesicular synaptobrevin-II levels. J Neurochem 2019; 151:28-37. [PMID: 31216055 PMCID: PMC6851701 DOI: 10.1111/jnc.14797] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/24/2019] [Accepted: 06/01/2019] [Indexed: 01/01/2023]
Abstract
The two most abundant molecules on synaptic vesicles (SVs) are synaptophysin and synaptobrevin‐II (sybII). SybII is essential for SV fusion, whereas synaptophysin is proposed to control the trafficking of sybII after SV fusion and its retrieval during endocytosis. Despite controlling key aspects of sybII packaging into SVs, the absence of synaptophysin results in negligible effects on neurotransmission. We hypothesised that this apparent absence of effect may be because of the abundance of sybII on SVs, with the impact of inefficient sybII retrieval only revealed during periods of repeated SV turnover. To test this hypothesis, we subjected primary cultures of synaptophysin knockout neurons to repeated trains of neuronal activity, while monitoring SV fusion events and levels of vesicular sybII. We identified a significant decrease in both the number of SV fusion events (monitored using the genetically encoded reporter vesicular glutamate transporter‐pHluorin) and vesicular sybII levels (via both immunofluorescence and Western blotting) using this protocol. This revealed that synaptophysin is essential to sustain both parameters during periods of repetitive SV turnover. This was confirmed by the rescue of presynaptic performance by the expression of exogenous synaptophysin. Importantly, the expression of exogenous sybII also fully restored SV fusion events in synaptophysin knockout neurons. The ability of additional copies of sybII to fully rescue presynaptic performance in these knockout neurons suggests that the principal role of synaptophysin is to mediate the efficient retrieval of sybII to sustain neurotransmitter release. ![]()
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Affiliation(s)
- Alexandros C Kokotos
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Callista B Harper
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Jamie R K Marland
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Karen J Smillie
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Sarah L Gordon
- The Florey Institute of Neuroscience and Mental Health, and Melbourne Dementia Research Centre, The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
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Taylor RD, Heine M, Emptage NJ, Andreae LC. Neuronal Receptors Display Cytoskeleton-Independent Directed Motion on the Plasma Membrane. iScience 2018; 10:234-244. [PMID: 30557785 PMCID: PMC6297241 DOI: 10.1016/j.isci.2018.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/25/2018] [Accepted: 11/30/2018] [Indexed: 11/19/2022] Open
Abstract
Directed transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single-particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe that specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.
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Affiliation(s)
- Ruth D Taylor
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Martin Heine
- Leibniz Institute of Neurobiology, Research Group Molecular Physiology, Brenneckestrasse 6, Magdeburg 39118, Germany; Otto von Guericke University Magdeburg, Center for Behavioral Brain Sciences (CBBS), Universitätsplatz 2, Magdeburg 39106, Germany; Johannes Gutenberg University Mainz, Institute for Developmental Biology and Neurobiology, AG Funktional Neurobiology, Hanns-Dieter-Hüsch Weg 15, Mainz 55128, Germany
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Laura C Andreae
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
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40
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A viral-fusion-peptide-like molecular switch drives membrane insertion of botulinum neurotoxin A1. Nat Commun 2018; 9:5367. [PMID: 30560862 PMCID: PMC6299077 DOI: 10.1038/s41467-018-07789-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 11/22/2018] [Indexed: 11/09/2022] Open
Abstract
Botulinum neurotoxin (BoNT) delivers its protease domain across the vesicle membrane to enter the neuronal cytosol upon vesicle acidification. This process is mediated by its translocation domain (HN), but the molecular mechanism underlying membrane insertion of HN remains poorly understood. Here, we report two crystal structures of BoNT/A1 HN that reveal a novel molecular switch (termed BoNT-switch) in HN, where buried α-helices transform into surface-exposed hydrophobic β-hairpins triggered by acidic pH. Locking the BoNT-switch by disulfide trapping inhibited the association of HN with anionic liposomes, blocked channel formation by HN, and reduced the neurotoxicity of BoNT/A1 by up to ~180-fold. Single particle counting studies showed that an acidic environment tends to promote BoNT/A1 self-association on liposomes, which is partly regulated by the BoNT-switch. These findings suggest that the BoNT-switch flips out upon exposure to the acidic endosomal pH, which enables membrane insertion of HN that subsequently leads to LC delivery. The translocation domain (HN) of Botulinum neurotoxins (BoNTs) mediates the delivery of the BoNT light chain (LC) into neuronal cytosol. Here the authors provide insights into HN membrane insertion by determining the crystal structure of BoNT/A1 HN at acidic pH, which reveals a molecular switch in HN, where buried α-helices are transformed into surface-exposed hydrophobic β-hairpins.
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Localizing Proton-Mediated Inhibitory Feedback at the Retinal Horizontal Cell-Cone Synapse with Genetically-Encoded pH Probes. J Neurosci 2018; 39:651-662. [PMID: 30504272 DOI: 10.1523/jneurosci.1541-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 11/12/2018] [Accepted: 11/17/2018] [Indexed: 11/21/2022] Open
Abstract
Lateral inhibition in the vertebrate retina depends on a negative feedback synapse between horizontal cells (HCs) and rod and cone photoreceptors. A change in pH is thought to be the signal for negative feedback, but its spatial profile in the synaptic cleft is unknown. Here we use three different membrane proteins, each fused to the same genetically-encoded pH-sensitive Green Fluorescent Protein (GFP) (pHluorin), to probe synaptic pH in retina from transgenic zebrafish (Danio rerio) of either sex. We used the cone transducin promoter to express SynaptopHluorin (pHluorin on vesicle-associated membrane protein (VAMP2)) or CalipHluorin (pHluorin on an L-type Ca2+ channel) and the HC-specific connexin-55.5 promoter to express AMPApHluorin (pHluorin on an AMPA receptor). Stimulus light led to increased fluorescence of all three probes, consistent with alkalinization of the synaptic cleft. The receptive field size, sensitivity to surround illumination, and response to activation of an alien receptor expressed exclusively in HCs, are consistent with lateral inhibition as the trigger for alkalinization. However, SynaptopHluorin and AMPApHluorin, which are displaced farther from cone synaptic ribbons than CalipHluorin, reported a smaller pH change. Hence, unlike feedforward glutamatergic transmission, which spills over to allow cross talk between terminals in the cone network, the pH change underlying HC feedback is compartmentalized to individual synaptic invaginations within a cone terminal, consistent with private line communication.SIGNIFICANCE STATEMENT Lateral inhibition (LI) is a fundamental feature of information processing in sensory systems, enhancing contrast sensitivity and enabling edge discrimination. Horizontal cells (HCs) are the first cellular substrate of LI in the vertebrate retina, but the synaptic mechanisms underlying LI are not completely understood, despite decades of study. This paper makes a significant contribution to our understanding of LI, by showing that each HC-cone synapse is a "private-line" that operates independently from other HC-cone connections. Using transgenic zebrafish expressing pHluorin, a pH-sensitive GFP variant spliced onto three different protein platforms expressed either in cones or HCs we show that the feedback pH signal is constrained to individual cone terminals, and more stringently, to individual synaptic contact sites within each terminal.
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Midorikawa M. Real-time imaging of synaptic vesicle exocytosis by total internal reflection fluorescence (TIRF) microscopy. Neurosci Res 2018; 136:1-5. [DOI: 10.1016/j.neures.2018.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/29/2018] [Indexed: 12/15/2022]
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43
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Shaib AH, Staudt A, Harb A, Klose M, Shaaban A, Schirra C, Mohrmann R, Rettig J, Becherer U. Paralogs of the Calcium-Dependent Activator Protein for Secretion Differentially Regulate Synaptic Transmission and Peptide Secretion in Sensory Neurons. Front Cell Neurosci 2018; 12:304. [PMID: 30254567 PMCID: PMC6141663 DOI: 10.3389/fncel.2018.00304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022] Open
Abstract
The two paralogs of the calcium-dependent activator protein for secretion (CAPS) are priming factors for synaptic vesicles (SVs) and neuropeptide containing large dense-core vesicles (LDCVs). Yet, it is unclear whether CAPS1 and CAPS2 regulate exocytosis of these two vesicle types differentially in dorsal root ganglion (DRG) neurons, wherein synaptic transmission and neuropeptide release are of equal importance. These sensory neurons transfer information from the periphery to the spinal cord (SC), releasing glutamate as the primary neurotransmitter, with co-transmission via neuropeptides in a subset of so called peptidergic neurons. Neuropeptides are key components of the information-processing machinery of pain perception and neuropathic pain generation. Here, we compared the ability of CAPS1 and CAPS2 to support priming of both vesicle types in single and double knock-out mouse (DRG) neurons using a variety of high-resolution live cell imaging methods. While CAPS1 was localized to synapses of all DRG neurons and promoted synaptic transmission, CAPS2 was found exclusively in peptidergic neurons and mediated LDCV exocytosis. Intriguingly, ectopic expression of CAPS2 empowered non-peptidergic neurons to drive LDCV fusion, thereby identifying CAPS2 as an essential molecular determinant for peptidergic signaling. Our results reveal that these distinct functions of both CAPS paralogs are based on their differential subcellular localization in DRG neurons. Our data suggest a major role for CAPS2 in neuropathic pain via control of neuropeptide release.
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Affiliation(s)
- Ali H. Shaib
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Angelina Staudt
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ali Harb
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Margarete Klose
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ahmed Shaaban
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Claudia Schirra
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ralf Mohrmann
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Jens Rettig
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ute Becherer
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
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Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804743] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yong Woong Jun
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
- Center for Converging Humanities; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Donghee Ma
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
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45
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Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018; 57:10142-10147. [PMID: 29873167 DOI: 10.1002/anie.201804743] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Indexed: 11/10/2022]
Abstract
Vesicles exchange their contents through membrane fusion processes, kiss-and-run and full-collapse fusion. Indirect observation of these fusion processes using artificial vesicles enhanced our understanding on the molecular mechanisms involved. Direct observation of the fusion processes in a real biological system, however, remains a challenge owing to many technical obstacles. We report a ratiometric two-photon probe offering real-time tracking of lysosomal ATP with quantitative information for the first time. By applying the probe to two-photon live-cell imaging, the lysosomal membrane fusion process in cells has been directly observed and the concentration of its content, lysosomal ATP, has been measured. Results show that the kiss-and-run process between lysosomes proceeds through repeated transient interactions with gradual content mixing, whereas the full-fusion process occurs at once. Furthermore, it is confirmed that both the fusion processes proceed with conservation of the content. Such a small-molecule probe exerts minimal disturbance and hence has potential for studying various biological processes associated with lysosomal ATP.
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Affiliation(s)
- Yong Woong Jun
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea.,Center for Converging Humanities, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Donghee Ma
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
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46
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Lou X. Sensing Exocytosis and Triggering Endocytosis at Synapses: Synaptic Vesicle Exocytosis-Endocytosis Coupling. Front Cell Neurosci 2018; 12:66. [PMID: 29593500 PMCID: PMC5861208 DOI: 10.3389/fncel.2018.00066] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/26/2018] [Indexed: 12/29/2022] Open
Abstract
The intact synaptic structure is critical for information processing in neural circuits. During synaptic transmission, rapid vesicle exocytosis increases the size of never terminals and endocytosis counteracts the increase. Accumulating evidence suggests that SV exocytosis and endocytosis are tightly connected in time and space during SV recycling, and this process is essential for synaptic function and structural stability. Research in the past has illustrated the molecular details of synaptic vesicle (SV) exocytosis and endocytosis; however, the mechanisms that timely connect these two fundamental events are poorly understood at central synapses. Here we discuss recent progress in SV recycling and summarize several emerging mechanisms by which synapses can “sense” the occurrence of exocytosis and timely initiate compensatory endocytosis. They include Ca2+ sensing, SV proteins sensing, and local membrane stress sensing. In addition, the spatial organization of endocytic zones adjacent to active zones provides a structural basis for efficient coupling between SV exocytosis and endocytosis. Through linking different endocytosis pathways with SV fusion, these mechanisms ensure necessary plasticity and robustness of nerve terminals to meet diverse physiological needs.
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Affiliation(s)
- Xuelin Lou
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
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47
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Kahms M, Klingauf J. Novel pH-Sensitive Lipid Based Exo-Endocytosis Tracers Reveal Fast Intermixing of Synaptic Vesicle Pools. Front Cell Neurosci 2018; 12:18. [PMID: 29456492 PMCID: PMC5801418 DOI: 10.3389/fncel.2018.00018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/11/2018] [Indexed: 11/13/2022] Open
Abstract
Styryl dyes and genetically encoded pH-sensitive fluorescent proteins like pHluorin are well-established tools for the optical analysis of synaptic vesicle (SV) recycling at presynaptic boutons. Here, we describe the development of a new class of fluorescent probes based on pH-sensitive organic dyes covalently bound to lipids, providing a promising complementary assay to genetically encoded fluorescent probes. These new optical tracers allow a pure read out of membrane turnover during synaptic activity and visualization of multiple rounds of stimulation-dependent SV recycling without genetic perturbation. Measuring the incorporation efficacy of different dye-labeled lipids into budding SVs, we did not observe an enrichment of lipids with affinity for liquid ordered membrane domains. But most importantly, we found no evidence for a static segregation of SVs into recycling and resting pools. A small but significant fraction of SVs that is reluctant to release during a first round of evoked activity can be exocytosed during a second bout of stimulation, showing fast intermixing of SV pools within seconds. Furthermore, we found that SVs recycling spontaneously have a higher chance to re-occupy release sites than SVs recycling during high-frequency evoked activity. In summary, our data provide strong evidence for a highly dynamic and use-dependent control of the fractions of releasable or resting SVs.
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Affiliation(s)
- Martin Kahms
- Department of Cellular Biophysics, Institute of Medical Physics and Biophysics, University of Münster, Münster, Germany
| | - Jürgen Klingauf
- Department of Cellular Biophysics, Institute of Medical Physics and Biophysics, University of Münster, Münster, Germany
- IZKF Münster and Cluster of Excellence Cells in Motion, University of Münster, Münster, Germany
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48
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McInnes J, Wierda K, Snellinx A, Bounti L, Wang YC, Stancu IC, Apóstolo N, Gevaert K, Dewachter I, Spires-Jones TL, De Strooper B, De Wit J, Zhou L, Verstreken P. Synaptogyrin-3 Mediates Presynaptic Dysfunction Induced by Tau. Neuron 2018; 97:823-835.e8. [DOI: 10.1016/j.neuron.2018.01.022] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 11/25/2022]
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49
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Mori Y, Takamori S. Molecular Signatures Underlying Synaptic Vesicle Cargo Retrieval. Front Cell Neurosci 2018; 11:422. [PMID: 29379416 PMCID: PMC5770824 DOI: 10.3389/fncel.2017.00422] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 12/15/2017] [Indexed: 12/31/2022] Open
Abstract
Efficient retrieval of the synaptic vesicle (SV) membrane from the presynaptic plasma membrane, a process called endocytosis, is crucial for the fidelity of neurotransmission, particularly during sustained neural activity. Although multiple modes of endocytosis have been identified, it is clear that the efficient retrieval of the major SV cargos into newly formed SVs during any of these modes is fundamental for synaptic transmission. It is currently believed that SVs are eventually reformed via a clathrin-dependent pathway. Various adaptor proteins recognize SV cargos and link them to clathrin, ensuring the efficient retrieval of the cargos into newly formed SVs. Here, we summarize our current knowledge of the molecular signatures within individual SV cargos that underlie efficient retrieval into SV membranes, as well as discuss possible contributions of the mechanisms under physiological conditions.
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Affiliation(s)
- Yasunori Mori
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Shigeo Takamori
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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50
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Joensuu M, Martínez-Mármol R, Padmanabhan P, Glass NR, Durisic N, Pelekanos M, Mollazade M, Balistreri G, Amor R, Cooper-White JJ, Goodhill GJ, Meunier FA. Visualizing endocytic recycling and trafficking in live neurons by subdiffractional tracking of internalized molecules. Nat Protoc 2017; 12:2590-2622. [PMID: 29189775 DOI: 10.1038/nprot.2017.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Our understanding of endocytic pathway dynamics is restricted by the diffraction limit of light microscopy. Although super-resolution techniques can overcome this issue, highly crowded cellular environments, such as nerve terminals, can also dramatically limit the tracking of multiple endocytic vesicles such as synaptic vesicles (SVs), which in turn restricts the analytical dissection of their discrete diffusional and transport states. We recently introduced a pulse-chase technique for subdiffractional tracking of internalized molecules (sdTIM) that allows the visualization of fluorescently tagged molecules trapped in individual signaling endosomes and SVs in presynapses or axons with 30- to 50-nm localization precision. We originally developed this approach for tracking single molecules of botulinum neurotoxin type A, which undergoes activity-dependent internalization and retrograde transport in autophagosomes. This method was then adapted to localize the signaling endosomes containing cholera toxin subunit-B that undergo retrograde transport in axons and to track SVs in the crowded environment of hippocampal presynapses. We describe (i) the construction of a custom-made microfluidic device that enables control over neuronal orientation; (ii) the 3D printing of a perfusion system for sdTIM experiments performed on glass-bottom dishes; (iii) the dissection, culturing and transfection of hippocampal neurons in microfluidic devices; and (iv) guidance on how to perform the pulse-chase experiments and data analysis. In addition, we describe the use of single-molecule-tracking analytical tools to reveal the average and the heterogeneous single-molecule mobility behaviors. We also discuss alternative reagents and equipment that can, in principle, be used for sdTIM experiments and describe how to adapt sdTIM to image nanocluster formation and/or tubulation in early endosomes during sorting events. The procedures described in this protocol take ∼1 week.
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Affiliation(s)
- Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.,Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Ramon Martínez-Mármol
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Pranesh Padmanabhan
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Nick R Glass
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Nela Durisic
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthew Pelekanos
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Mahdie Mollazade
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Giuseppe Balistreri
- Division of General Microbiology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Rumelo Amor
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Justin J Cooper-White
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia.,Division of General Microbiology, Department of Biosciences, University of Helsinki, Helsinki, Finland.,School of Chemical Engineering, The University of Queensland, Brisbane, Queensland, Australia.,Materials Science and Engineering Division, CSIRO, Clayton, Victoria, Australia.,UQ Centre for Stem Cell Ageing and Regenerative Engineering, The University of Queensland, Brisbane, Queensland, Australia
| | - Geoffrey J Goodhill
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.,School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
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