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Kroll J, Özçete ÖD, Jung S, Maritzen T, Milosevic I, Wichmann C, Moser T. AP180 promotes release site clearance and clathrin-dependent vesicle reformation in mouse cochlear inner hair cells. J Cell Sci 2019; 133:jcs.236737. [DOI: 10.1242/jcs.236737] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022] Open
Abstract
High-throughput neurotransmission at ribbon synapses of cochlear inner hair cells (IHCs) requires tight coupling of neurotransmitter release and balanced recycling of synaptic vesicles (SVs) as well as rapid restoration of release sites. Here, we examined the role of the adaptor protein AP180 for IHC synaptic transmission in AP180-KO mice using high-pressure freezing and electron tomography, confocal microscopy, patch-clamp membrane-capacitance measurements and systems physiology. AP180 was found predominantly at the synaptic pole of IHCs. AP180-deficient IHCs had severely reduced SV numbers, slowed endocytic membrane retrieval, and accumulated endocytic intermediates near ribbon synapses, indicating that AP180 is required for clathrin-dependent endocytosis and SV reformation in IHCs. Moreover, AP180 deletion led to a high prevalence of SVs in a multi-tethered or docked state after stimulation, a reduced rate of SV replenishment, and a hearing impairment. We conclude that, in addition to its role in clathrin recruitment, AP180 contributes to release site clearance in IHCs.
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Affiliation(s)
- Jana Kroll
- Synaptic Vesicle Dynamics Group, European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-Society, Göttingen, Germany
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Göttingen Graduate School for Neuroscience and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Özge Demet Özçete
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Göttingen Graduate School for Neuroscience and Molecular Biosciences, University of Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sangyong Jung
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Neuro Modulation and Neuro Circuitry Group, Singapore Bioimaging Consortium (SBIC), Biomedical Sciences Institutes, 138667 Singapore
| | - Tanja Maritzen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Ira Milosevic
- Synaptic Vesicle Dynamics Group, European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-Society, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience, InnerEarLab and Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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52
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Maidorn M, Olichon A, Rizzoli SO, Opazo F. Nanobodies reveal an extra-synaptic population of SNAP-25 and Syntaxin 1A in hippocampal neurons. MAbs 2018; 11:305-321. [PMID: 30466346 PMCID: PMC6380399 DOI: 10.1080/19420862.2018.1551675] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Synaptic vesicle fusion (exocytosis) is a precisely regulated process that entails the formation of SNARE complexes between the vesicle protein synaptobrevin 2 (VAMP2) and the plasma membrane proteins Syntaxin 1 and SNAP-25. The sub-cellular localization of the latter two molecules remains unclear, although they have been the subject of many recent investigations. To address this, we generated two novel camelid single domain antibodies (nanobodies) specifically binding to SNAP-25 and Syntaxin 1A. These probes penetrated more easily into samples and detected their targets more efficiently than conventional antibodies in crowded regions. When investigated by super-resolution imaging, the nanobodies revealed substantial extra-synaptic populations for both SNAP-25 and Syntaxin 1A, which were poorly detected by antibodies. Moreover, extra-synaptic Syntaxin 1A molecules were recruited to synapses during stimulation, suggesting that these are physiologically-active molecules. We conclude that nanobodies are able to reveal qualitatively and quantitatively different organization patterns, when compared to conventional antibodies.
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Affiliation(s)
- Manuel Maidorn
- a Institute of Neuro- and Sensory Physiology , University Medical Center Göttingen , Göttingen , Germany.,b Center for Biostructural Imaging of Neurodegeneration (BIN) , University of Göttingen Medical Center , Göttingen , Germany
| | - Aurélien Olichon
- c Inserm, UMR 1037-CRCT , Toulouse , France.,d Université Toulouse III-Paul Sabatier , Toulouse , France
| | - Silvio O Rizzoli
- a Institute of Neuro- and Sensory Physiology , University Medical Center Göttingen , Göttingen , Germany.,b Center for Biostructural Imaging of Neurodegeneration (BIN) , University of Göttingen Medical Center , Göttingen , Germany
| | - Felipe Opazo
- a Institute of Neuro- and Sensory Physiology , University Medical Center Göttingen , Göttingen , Germany.,b Center for Biostructural Imaging of Neurodegeneration (BIN) , University of Göttingen Medical Center , Göttingen , Germany
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53
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Jaykumar AB, Caceres PS, Ortiz PA. Single-molecule labeling for studying trafficking of renal transporters. Am J Physiol Renal Physiol 2018; 315:F1243-F1249. [PMID: 30043625 DOI: 10.1152/ajprenal.00082.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to detect and track single molecules presents the advantage of visualizing the complex behavior of transmembrane proteins with a time and space resolution that would otherwise be lost with traditional labeling and biochemical techniques. Development of new imaging probes has provided a robust method to study their trafficking and surface dynamics. This mini-review focuses on the current technology available for single-molecule labeling of transmembrane proteins, their advantages, and limitations. We also discuss the application of these techniques to the study of renal transporter trafficking in light of recent research.
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Affiliation(s)
- Ankita Bachhawat Jaykumar
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan.,Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan
| | - Paulo S Caceres
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
| | - Pablo A Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan.,Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan
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54
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Woodring J, Behera R, Sharma A, Wiedeman J, Patel G, Singh B, Guyett P, Amata E, Erath J, Roncal N, Penn E, Leed SE, Rodriguez A, Sciotti RJ, Mensa-Wilmot K, Pollastri MP. Series of Alkynyl-Substituted Thienopyrimidines as Inhibitors of Protozoan Parasite Proliferation. ACS Med Chem Lett 2018; 9:996-1001. [PMID: 30344906 PMCID: PMC6187419 DOI: 10.1021/acsmedchemlett.8b00245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/04/2018] [Indexed: 12/23/2022] Open
Abstract
Discovery of new chemotherapeutic lead agents can be accelerated by optimizing chemotypes proven to be effective in other diseases to act against parasites. One such medicinal chemistry campaign has focused on optimizing the anilinoquinazoline drug lapatinib (1) and the alkynyl thieno[3,2-d]pyrimidine hit GW837016X (NEU-391, 3) into leads for antitrypanosome drugs. We now report the structure-activity relationship studies of 3 and its analogs against Trypanosoma brucei, which causes human African trypanosomiasis (HAT). The series was also tested against Trypanosoma cruzi, Leishmania major, and Plasmodium falciparum. In each case, potent antiparasitic hits with acceptable toxicity margins over mammalian HepG2 and NIH3T3 cell lines were identified. In a mouse model of HAT, 3 extended life of treated mice by 50%, compared to untreated controls. At the cellular level, 3 inhibited mitosis and cytokinesis in T. brucei. Thus, the alkynylthieno[3,2-d]pyrimidine chemotype is an advanced hit worthy of further optimization as a potential chemotherapeutic agent for HAT.
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Affiliation(s)
- Jennifer
L. Woodring
- Department
of Chemistry & Chemical Biology, Northeastern
University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ranjan Behera
- Department
of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, United States
| | - Amrita Sharma
- Department
of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, United States
| | - Justin Wiedeman
- Department
of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, United States
| | - Gautam Patel
- Department
of Chemistry & Chemical Biology, Northeastern
University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Baljinder Singh
- Department
of Chemistry & Chemical Biology, Northeastern
University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Paul Guyett
- Department
of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, United States
| | - Emanuele Amata
- Department
of Chemistry & Chemical Biology, Northeastern
University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Jessey Erath
- Department
of Microbiology, New York University School
of Medicine, 430 E. 29th Street New York, New York 10010, United
States
- Anti-Infectives
Screening Core, New York University School
of Medicine, New York, New York 10010, United
States
| | - Norma Roncal
- Experimental
Therapeutics, Walter Reed Army Institute
of Research, 2460 Linden Lane, Silver Spring, Maryland 20910, United
States
| | - Erica Penn
- Experimental
Therapeutics, Walter Reed Army Institute
of Research, 2460 Linden Lane, Silver Spring, Maryland 20910, United
States
| | - Susan E. Leed
- Experimental
Therapeutics, Walter Reed Army Institute
of Research, 2460 Linden Lane, Silver Spring, Maryland 20910, United
States
| | - Ana Rodriguez
- Department
of Microbiology, New York University School
of Medicine, 430 E. 29th Street New York, New York 10010, United
States
- Anti-Infectives
Screening Core, New York University School
of Medicine, New York, New York 10010, United
States
| | - Richard J. Sciotti
- Experimental
Therapeutics, Walter Reed Army Institute
of Research, 2460 Linden Lane, Silver Spring, Maryland 20910, United
States
| | - Kojo Mensa-Wilmot
- Department
of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, United States
| | - Michael P. Pollastri
- Department
of Chemistry & Chemical Biology, Northeastern
University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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55
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Pangrsic T, Vogl C. Balancing presynaptic release and endocytic membrane retrieval at hair cell ribbon synapses. FEBS Lett 2018; 592:3633-3650. [PMID: 30251250 DOI: 10.1002/1873-3468.13258] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 11/07/2022]
Abstract
The timely and reliable processing of auditory and vestibular information within the inner ear requires highly sophisticated sensory transduction pathways. On a cellular level, these demands are met by hair cells, which respond to sound waves - or alterations in body positioning - by releasing glutamate-filled synaptic vesicles (SVs) from their presynaptic active zones with unprecedented speed and exquisite temporal fidelity, thereby initiating the auditory and vestibular pathways. In order to achieve this, hair cells have developed anatomical and molecular specializations, such as the characteristic and name-giving 'synaptic ribbons' - presynaptically anchored dense bodies that tether SVs prior to release - as well as other unique or unconventional synaptic proteins. The tightly orchestrated interplay between these molecular components enables not only ultrafast exocytosis, but similarly rapid and efficient compensatory endocytosis. So far, the knowledge of how endocytosis operates at hair cell ribbon synapses is limited. In this Review, we summarize recent advances in our understanding of the SV cycle and molecular anatomy of hair cell ribbon synapses, with a focus on cochlear inner hair cells.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, University Medical Center Göttingen, Germany
| | - Christian Vogl
- Presynaptogenesis and Intracellular Transport in Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, University Medical Center Göttingen, Germany
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56
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Wu D, Cheung S, Sampedro G, Chen ZL, Cahill RA, O'Shea DF. A DIE responsive NIR-fluorescent cell membrane probe. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2272-2280. [PMID: 30409523 DOI: 10.1016/j.bbamem.2018.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/30/2018] [Accepted: 09/06/2018] [Indexed: 11/26/2022]
Abstract
It is challenging to achieve selective off to on modulation of the emissive state of a fluorophore within a complex and heterogeneous cellular environment. Herein we show that the dis-assembly of a non-fluorescent aggregate to produce individual fluorescent molecules, termed disaggregation induced emission (DIE), can be utilised to achieve this goal with an amphiphilic BF2-azadipyrromethene (NIR-AZA) probe. Optical near-infrared properties of the NIR-AZA probe used in this study include absorption and emission maxima at 700 and 726 nm respectively when in the emissive non-aggregated state. Key to the success of the probe is the bis-sulfonic acid substitution of the NIR-AZA fluorophore, which is atypical for membrane probes as it does not contain zwitterionic lipid substituents. The aggregation/disaggregation properties of the NIR-fluorophore have been investigated in model surfactant and synthetic liposomal systems and shown to be emissive responsive to both. Real-time live cell imaging experiments in HeLa Kyoto and MC3T3 cells showed a rapid switch on of emission specific to the plasma membrane of viable and apoptotic cells attributable to a disaggregation-induced emission of the probe. Image analysis software confirmed localisation of fluorescence to the plasma membrane. Cell membrane staining was also effective for formaldehyde fixed cells, with staining possible either before or after fixation. This study adds new and important findings to recent developments of DIE responsive probes and further applications of this controllable emission-switching event are anticipated.
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Affiliation(s)
- Dan Wu
- Department of Chemistry, RCSI, 123 St Stephen's Green, Dublin 2, Ireland
| | - Shane Cheung
- Department of Chemistry, RCSI, 123 St Stephen's Green, Dublin 2, Ireland
| | - Gonzalo Sampedro
- Department of Chemistry, RCSI, 123 St Stephen's Green, Dublin 2, Ireland
| | - Zhi-Long Chen
- Department of Pharmaceutical Science & Technology, College of Chemistry and Biology, Donghua University, Shanghai 201620, China
| | - Ronan A Cahill
- Department of Surgery, Mater Misericordiae University Hospital (MMUH), School of Medicine, University College Dublin, Dublin, Ireland
| | - Donal F O'Shea
- Department of Chemistry, RCSI, 123 St Stephen's Green, Dublin 2, Ireland.
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57
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Copine-6 Binds to SNAREs and Selectively Suppresses Spontaneous Neurotransmission. J Neurosci 2018; 38:5888-5899. [PMID: 29802203 DOI: 10.1523/jneurosci.0461-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/11/2018] [Accepted: 05/21/2018] [Indexed: 11/21/2022] Open
Abstract
Recent studies suggest that spontaneous and action potential-evoked neurotransmitter release processes are independently regulated. However, the mechanisms that uncouple the two forms of neurotransmission remain unclear. In cultured mouse and rat neurons, we show that the two C2 domain-containing protein copine-6 is localized to presynaptic terminals and binds to synaptobrevin2 as well as other SNARE proteins in a Ca2+-dependent manner. Ca2+-dependent interaction of copine-6 with synaptobrevin2 selectively suppresses spontaneous neurotransmission in a reaction that requires the tandem tryptophan residues at the C-terminal region of synaptobrevin2. Accordingly, copine-6 loss of function augmented presynaptic Ca2+ elevation-mediated neurotransmitter release. Intracellular Ca2+ chelation, on the other hand, occluded copine-6-mediated suppression of release. We also evaluated the molecular specificity of the copine-6-dependent regulation of spontaneous release and found that overexpression of copine-6 did not suppress spontaneous release in synaptobrevin2-deficient neurons. Together, these results suggest that copine-6 acts as a specific Ca2+-dependent suppressor of spontaneous neurotransmission.SIGNIFICANCE STATEMENT Synaptic transmission occurs both in response to presynaptic action potentials and spontaneously, in the absence of stimulation. Currently, much more is understood about the mechanisms underlying action potential-evoked neurotransmission compared with spontaneous release. However, recent studies have shown selective modulation of spontaneous neurotransmission process by several neuromodulators, suggesting specific molecular regulation of spontaneous release. In this study, we identify copine-6 as a specific regulator of spontaneous neurotransmission. By both gain-of-function and loss-of-function experiments, we show that copine-6 functions as a Ca2+-dependent suppressor of spontaneous release. These results further elucidate the mechanisms underlying differential regulation of evoked and spontaneous neurotransmitter release.
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58
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Wiedeman J, Mensa-Wilmot K. A fixable probe for visualizing flagella and plasma membranes of the African trypanosome. PLoS One 2018; 13:e0197541. [PMID: 29768499 PMCID: PMC5955550 DOI: 10.1371/journal.pone.0197541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/03/2018] [Indexed: 12/22/2022] Open
Abstract
The protozoan Trypanosoma brucei sp. cause diseases in humans and animals. Studies of T. brucei cell biology have revealed unique features, such as major endocytic events being limited to a single region, and mitochondrial genome segregation mediated via basal bodies. Further understanding of trypanosome cell biology can be facilitated with super-resolution fluorescence microscopy. Lack of a plasma membrane probe for fixed trypanosomes remains a persistent problem in need of a working solution. Herein, we report protocols developed using mCLING in super-resolution structured illumination fluorescence microscopy (SR-SIM). mCLING comprehensively labels flagellar membranes, including nascent intracellular stages. To extend its usefulness for trypanosome biology we optimized mCLING in combination with organelle-specific antibodies for immunofluorescence of basal bodies or mitochondria. Then in work with live trypanosomes, we demonstrated internalization of mCLING into endocytic stations that overlap with LysoTracker in acidic organelles. Greater detail of the intracellular location of mCLING was obtained with SR-SIM after pulsing trypanosomes with the probe, and allowing continuous uptake of fluorescent concanavalin A (ConA) destined for lysosomes. In most cases, ConA and mCLING vesicles were juxtaposed but not coincident. A video of the complete image stack at the 15 min time point shows zones of mCLING staining surrounding patches of ConA, consistent with persistence of mCLING in membranes of compartments that contain luminal ConA. In summary, these studies establish mCLING as a versatile trypanosome membrane probe compatible with super-resolution microscopy that can be used for detailed analysis of flagellar membrane biogenesis. In addition, mCLING can be used for immunofluorescence in fixed, permeabilized trypanosomes. Its robust staining of the plasma membrane eliminates a need to overlay transmitted light images on fluorescence pictures obtained from widefield, confocal, or super-resolution microscopy.
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Affiliation(s)
- Justin Wiedeman
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Kojo Mensa-Wilmot
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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59
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Shin W, Ge L, Arpino G, Villarreal SA, Hamid E, Liu H, Zhao WD, Wen PJ, Chiang HC, Wu LG. Visualization of Membrane Pore in Live Cells Reveals a Dynamic-Pore Theory Governing Fusion and Endocytosis. Cell 2018; 173:934-945.e12. [PMID: 29606354 PMCID: PMC5935532 DOI: 10.1016/j.cell.2018.02.062] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/22/2018] [Accepted: 02/27/2018] [Indexed: 01/03/2023]
Abstract
Fusion is thought to open a pore to release vesicular cargoes vital for many biological processes, including exocytosis, intracellular trafficking, fertilization, and viral entry. However, fusion pores have not been observed and thus proved in live cells. Its regulatory mechanisms and functions remain poorly understood. With super-resolution STED microscopy, we observed dynamic fusion pore behaviors in live (neuroendocrine) cells, including opening, expansion, constriction, and closure, where pore size may vary between 0 and 490 nm within 26 milliseconds to seconds (vesicle size: 180-720 nm). These pore dynamics crucially determine the efficiency of vesicular cargo release and vesicle retrieval. They are generated by competition between pore expansion and constriction. Pharmacology and mutation experiments suggest that expansion and constriction are mediated by F-actin-dependent membrane tension and calcium/dynamin, respectively. These findings provide the missing live-cell evidence, proving the fusion-pore hypothesis, and establish a live-cell dynamic-pore theory accounting for fusion, fission, and their regulation.
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Affiliation(s)
- Wonchul Shin
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Lihao Ge
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Gianvito Arpino
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Seth A Villarreal
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Edaeni Hamid
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Huisheng Liu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Wei-Dong Zhao
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Peter J Wen
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Hsueh-Cheng Chiang
- 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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60
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Furusato T, Horie F, Matsubayashi HT, Amikura K, Kuruma Y, Ueda T. De Novo Synthesis of Basal Bacterial Cell Division Proteins FtsZ, FtsA, and ZipA Inside Giant Vesicles. ACS Synth Biol 2018; 7:953-961. [PMID: 29510621 DOI: 10.1021/acssynbio.7b00350] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cell division is the most dynamic event in the cell cycle. Recently, efforts have been made to reconstruct it using the individual component proteins to obtain a better understanding of the process of self-reproduction of cells. However, such reconstruction studies are frequently hampered by difficulties in preparing membrane-associated proteins. Here we demonstrate a de novo synthesis approach based on a cell-free translation system. Genes for fundamental cell division proteins, FtsZ, FtsA, and ZipA, were expressed inside the lipid compartment of giant vesicles (GVs). The synthesized proteins showed polymerization, membrane localization, and eventually membrane deformation. Notably, we found that this morphological change of the vesicle is forced by only FtsZ and ZipA, which form clusters on the membrane at the vesicle interior. Our cell-free approach provides a platform for studying protein dynamics associated with lipid membrane and paves the way to create a synthetic cell that undergoes self-reproduction.
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Affiliation(s)
- Takumi Furusato
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bldg. FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Fumihiro Horie
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bldg. FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Hideaki T. Matsubayashi
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bldg. FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Kazuaki Amikura
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bldg. FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Yutetsu Kuruma
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Takuya Ueda
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bldg. FSB-401, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
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61
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Richter KN, Revelo NH, Seitz KJ, Helm MS, Sarkar D, Saleeb RS, D'Este E, Eberle J, Wagner E, Vogl C, Lazaro DF, Richter F, Coy-Vergara J, Coceano G, Boyden ES, Duncan RR, Hell SW, Lauterbach MA, Lehnart SE, Moser T, Outeiro TF, Rehling P, Schwappach B, Testa I, Zapiec B, Rizzoli SO. Glyoxal as an alternative fixative to formaldehyde in immunostaining and super-resolution microscopy. EMBO J 2018; 37:139-159. [PMID: 29146773 PMCID: PMC5753035 DOI: 10.15252/embj.201695709] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 09/25/2017] [Accepted: 10/06/2017] [Indexed: 12/02/2022] Open
Abstract
Paraformaldehyde (PFA) is the most commonly used fixative for immunostaining of cells, but has been associated with various problems, ranging from loss of antigenicity to changes in morphology during fixation. We show here that the small dialdehyde glyoxal can successfully replace PFA Despite being less toxic than PFA, and, as most aldehydes, likely usable as a fixative, glyoxal has not yet been systematically tried in modern fluorescence microscopy. Here, we tested and optimized glyoxal fixation and surprisingly found it to be more efficient than PFA-based protocols. Glyoxal acted faster than PFA, cross-linked proteins more effectively, and improved the preservation of cellular morphology. We validated glyoxal fixation in multiple laboratories against different PFA-based protocols and confirmed that it enabled better immunostainings for a majority of the targets. Our data therefore support that glyoxal can be a valuable alternative to PFA for immunostaining.
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Affiliation(s)
- Katharina N Richter
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Göttingen, Germany
- Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Natalia H Revelo
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Göttingen, Germany
| | - Katharina J Seitz
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Göttingen, Germany
- International Max Planck Research School Molecular Biology, Göttingen, Germany
| | - Martin S Helm
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Göttingen, Germany
- International Max Planck Research School Molecular Biology, Göttingen, Germany
| | | | - Rebecca S Saleeb
- Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, Heriot-Watt University, Edinburgh, UK
| | - Elisa D'Este
- Department of NanoBiophotonics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Jessica Eberle
- Department of Neural Systems, Max-Planck-Institute for Brain Research, Frankfurt am Main, Germany
| | - Eva Wagner
- Heart Research Center Göttingen, Department of Cardiology & Pulmonology, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK) Site Göttingen
| | - Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Auditory Neuroscience Group, Göttingen, Germany
| | - Diana F Lazaro
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration University Medical Center Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Frank Richter
- International Max Planck Research School Molecular Biology, Göttingen, Germany
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Javier Coy-Vergara
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Giovanna Coceano
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Edward S Boyden
- Departments of Brain and Cognitive Science and Biological Engineering, MIT Media Lab and McGovern Institute, Cambridge, MA, USA
| | - Rory R Duncan
- Edinburgh Super-Resolution Imaging Consortium, Institute of Biological Chemistry, Biophysics, and Bioengineering, Heriot-Watt University, Edinburgh, UK
| | - Stefan W Hell
- Department of NanoBiophotonics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marcel A Lauterbach
- Department of Neural Systems, Max-Planck-Institute for Brain Research, Frankfurt am Main, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pulmonology, University Medical Center Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK) Site Göttingen
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Auditory Neuroscience Group, Göttingen, Germany
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration University Medical Center Göttingen, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
- Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Ilaria Testa
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Bolek Zapiec
- Max Planck Research Unit for Neurogenetics, Frankfurt am Main, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Göttingen, Germany
- Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
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Taniguchi K, Shao Y, Townshend RF, Cortez CL, Harris CE, Meshinchi S, Kalantry S, Fu J, O'Shea KS, Gumucio DL. An apicosome initiates self-organizing morphogenesis of human pluripotent stem cells. J Cell Biol 2017; 216:3981-3990. [PMID: 29021220 PMCID: PMC5716285 DOI: 10.1083/jcb.201704085] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/21/2017] [Accepted: 09/06/2017] [Indexed: 12/26/2022] Open
Abstract
Human pluripotent stem cells (hPSCs) self-organize into apicobasally polarized cysts, reminiscent of the lumenal epiblast stage, providing a model to explore key morphogenic processes in early human embryos. Here, we show that apical polarization begins on the interior of single hPSCs through the dynamic formation of a highly organized perinuclear apicosome structure. The membrane surrounding the apicosome is enriched in apical markers and displays microvilli and a primary cilium; its lumenal space is rich in Ca2+ Time-lapse imaging of isolated hPSCs reveals that the apicosome forms de novo in interphase, retains its structure during mitosis, is asymmetrically inherited after mitosis, and relocates to the recently formed cytokinetic plane, where it establishes a fully polarized lumen. In a multicellular aggregate of hPSCs, intracellular apicosomes from multiple cells are trafficked to generate a common lumenal cavity. Thus, the apicosome is a unique preassembled apical structure that can be rapidly used in single or clustered hPSCs to initiate self-organized apical polarization and lumenogenesis.
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Affiliation(s)
- Kenichiro Taniguchi
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Yue Shao
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI
| | - Ryan F Townshend
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Chari L Cortez
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Clair E Harris
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI
| | - Sasha Meshinchi
- Microscopy and Image Analysis Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI
| | - Jianping Fu
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - K Sue O'Shea
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Deborah L Gumucio
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
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63
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Jensen KHR, Berg RW. Advances and perspectives in tissue clearing using CLARITY. J Chem Neuroanat 2017; 86:19-34. [DOI: 10.1016/j.jchemneu.2017.07.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 12/16/2022]
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64
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Michalski N, Goutman JD, Auclair SM, Boutet de Monvel J, Tertrais M, Emptoz A, Parrin A, Nouaille S, Guillon M, Sachse M, Ciric D, Bahloul A, Hardelin JP, Sutton RB, Avan P, Krishnakumar SS, Rothman JE, Dulon D, Safieddine S, Petit C. Otoferlin acts as a Ca 2+ sensor for vesicle fusion and vesicle pool replenishment at auditory hair cell ribbon synapses. eLife 2017; 6:e31013. [PMID: 29111973 PMCID: PMC5700815 DOI: 10.7554/elife.31013] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/06/2017] [Indexed: 01/01/2023] Open
Abstract
Hearing relies on rapid, temporally precise, and sustained neurotransmitter release at the ribbon synapses of sensory cells, the inner hair cells (IHCs). This process requires otoferlin, a six C2-domain, Ca2+-binding transmembrane protein of synaptic vesicles. To decipher the role of otoferlin in the synaptic vesicle cycle, we produced knock-in mice (OtofAla515,Ala517/Ala515,Ala517) with lower Ca2+-binding affinity of the C2C domain. The IHC ribbon synapse structure, synaptic Ca2+ currents, and otoferlin distribution were unaffected in these mutant mice, but auditory brainstem response wave-I amplitude was reduced. Lower Ca2+ sensitivity and delay of the fast and sustained components of synaptic exocytosis were revealed by membrane capacitance measurement upon modulations of intracellular Ca2+ concentration, by varying Ca2+ influx through voltage-gated Ca2+-channels or Ca2+ uncaging. Otoferlin thus functions as a Ca2+ sensor, setting the rates of primed vesicle fusion with the presynaptic plasma membrane and synaptic vesicle pool replenishment in the IHC active zone.
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Affiliation(s)
- Nicolas Michalski
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Juan D Goutman
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
| | - Sarah Marie Auclair
- Department of Cell BiologyYale University School of MedicineNew HavenUnited States
| | - Jacques Boutet de Monvel
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Margot Tertrais
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux NeurocampusUniversité de BordeauxBordeauxFrance
| | - Alice Emptoz
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Alexandre Parrin
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Sylvie Nouaille
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Marc Guillon
- Wave Front Engineering Microscopy Group, Neurophotonics Laboratory, Centre National de la Recherche Scientifique, UMR 8250University Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Martin Sachse
- Center for Innovation & Technological ResearchUltrapole, Institut PasteurParisFrance
| | - Danica Ciric
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Amel Bahloul
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
- Centre National de la Recherche ScientifiqueFrance
| | - Jean-Pierre Hardelin
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
| | - Roger Bryan Sutton
- Department of Cell Physiology and Molecular BiophysicsTexas Tech University Health Sciences CenterLubbockUnited States
- Center for Membrane Protein ResearchTexas Tech University Health Sciences CenterLubbockUnited States
| | - Paul Avan
- Laboratoire de Biophysique SensorielleUniversité Clermont AuvergneClermont-FerrandFrance
- UMR 1107, Institut National de la Santé et de la Recherche MédicaleClermont-FerrandFrance
- Centre Jean PerrinClermont-FerrandFrance
| | - Shyam S Krishnakumar
- Department of Cell BiologyYale University School of MedicineNew HavenUnited States
- Department of Clinical and Experimental EpilepsyInstitute of Neurology, University College LondonLondonUnited Kingdom
| | - James E Rothman
- Department of Cell BiologyYale University School of MedicineNew HavenUnited States
- Department of Clinical and Experimental EpilepsyInstitute of Neurology, University College LondonLondonUnited Kingdom
| | - Didier Dulon
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux NeurocampusUniversité de BordeauxBordeauxFrance
| | - Saaid Safieddine
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
- Centre National de la Recherche ScientifiqueFrance
| | - Christine Petit
- Unité de Génétique et Physiologie de l’AuditionInstitut PasteurParisFrance
- UMRS 1120, Institut National de la Santé et de la Recherche MédicaleParisFrance
- Sorbonne Universités, UPMC Université Paris 06, Complexité du VivantParisFrance
- Syndrome de Usher et Autres Atteintes Rétino-CochléairesInstitut de la VisionParisFrance
- Collège de FranceParisFrance
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65
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Baer A, Schmidt S, Haensch S, Eder M, Mayer G, Harrington MJ. Mechanoresponsive lipid-protein nanoglobules facilitate reversible fibre formation in velvet worm slime. Nat Commun 2017; 8:974. [PMID: 29042549 PMCID: PMC5645397 DOI: 10.1038/s41467-017-01142-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 08/22/2017] [Indexed: 12/23/2022] Open
Abstract
Velvet worms eject a fluid capture slime that can be mechanically drawn into stiff biopolymeric fibres. Remarkably, these fibres can be dissolved by extended exposure to water, and new regenerated fibres can be drawn from the dissolved fibre solution-indicating a fully recyclable process. Here, we perform a multiscale structural and compositional investigation of this reversible fabrication process with the velvet worm Euperipatoides rowelli, revealing that biopolymeric fibre assembly is facilitated via mono-disperse lipid-protein nanoglobules. Shear forces cause nanoglobules to self-assemble into nano- and microfibrils, which can be drawn into macroscopic fibres with a protein-enriched core and lipid-rich coating. Fibre dissolution in water leads to re-formation of nanoglobules, suggesting that this dynamic supramolecular assembly of mechanoresponsive protein-building blocks is mediated by reversible non-covalent interactions. These findings offer important mechanistic insights into the role of mechanochemical processes in bio-fibre formation, providing potential avenues for sustainable material fabrication processes.Velvet worms expel a fluid slime that, under shear force, forms stiff fibres that can be dissolved and then regenerated. Here, the authors reveal that the recyclability of these biopolymers relies on mechanoresponsive lipid-protein nanoglobules in the slime that reversibly self-assemble into fibrils.
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Affiliation(s)
- Alexander Baer
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany.
| | - Stephan Schmidt
- Institute of Organic and Macromolecular Chemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Sebastian Haensch
- Center for Advanced Imaging (CAi), Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Michaela Eder
- Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424, Potsdam, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany
| | - Matthew J Harrington
- Dept. of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424, Potsdam, Germany. .,Dept. of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC, H3A 0B8, Canada.
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66
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Meese S, Cepeda AP, Gahlen F, Adams CM, Ficner R, Ricci AJ, Heller S, Reisinger E, Herget M. Activity-Dependent Phosphorylation by CaMKIIδ Alters the Ca 2+ Affinity of the Multi-C 2-Domain Protein Otoferlin. Front Synaptic Neurosci 2017; 9:13. [PMID: 29046633 PMCID: PMC5632675 DOI: 10.3389/fnsyn.2017.00013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/11/2017] [Indexed: 01/20/2023] Open
Abstract
Otoferlin is essential for fast Ca2+-triggered transmitter release from auditory inner hair cells (IHCs), playing key roles in synaptic vesicle release, replenishment and retrieval. Dysfunction of otoferlin results in profound prelingual deafness. Despite its crucial role in cochlear synaptic processes, mechanisms regulating otoferlin activity have not been studied to date. Here, we identified Ca2+/calmodulin-dependent serine/threonine kinase II delta (CaMKIIδ) as an otoferlin binding partner by pull-downs from chicken utricles and reassured interaction by a co-immunoprecipitation with heterologously expressed proteins in HEK cells. We confirmed the expression of CaMKIIδ in rodent IHCs by immunohistochemistry and real-time PCR. A proximity ligation assay indicates close proximity of the two proteins in rat IHCs, suggesting that otoferlin and CaMKIIδ also interact in mammalian IHCs. In vitro phosphorylation of otoferlin by CaMKIIδ revealed ten phosphorylation sites, five of which are located within C2-domains. Exchange of serines/threonines at phosphorylated sites into phosphomimetic aspartates reduces the Ca2+ affinity of the recombinant C2F domain 10-fold, and increases the Ca2+ affinity of the C2C domain. Concordantly, we show that phosphorylation of otoferlin and/or its interaction partners are enhanced upon hair cell depolarization and blocked by pharmacological CaMKII inhibition. We therefore propose that otoferlin activity is regulated by CaMKIIδ in IHCs.
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Affiliation(s)
- Sandra Meese
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Andreia P Cepeda
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany.,Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Felix Gahlen
- Department of Otorhinolaryngology, Head and Neck Surgery, Ruhr-University Bochum, Bochum, Germany
| | - Christopher M Adams
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA, United States
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Anthony J Ricci
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Stefan Heller
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Ellen Reisinger
- Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Meike Herget
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
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67
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Niebert S, van Belle GJ, Vogelgesang S, Manzke T, Niebert M. The Serotonin Receptor Subtype 5b Specifically Interacts with Serotonin Receptor Subtype 1A. Front Mol Neurosci 2017; 10:299. [PMID: 28983239 PMCID: PMC5613149 DOI: 10.3389/fnmol.2017.00299] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/06/2017] [Indexed: 11/13/2022] Open
Abstract
Previously, we described the dysregulation of serotonin (5-HT) receptor subtype 5b (5-ht5b) in a mouse model of Rett syndrome (RTT). 5-ht5b has not been extensively studied, so we set out to characterize it in more detail. Unlike common cell surface receptors, 5-ht5b displays no membrane expression, while receptor clusters are located in endosomes. This unusual subcellular localization is at least in part controlled by glycosylation of the N-terminus, with 5-ht5b possessing fewer glycosylation sites than related receptors. We analyzed whether the localization to endosomes has any functional relevance and found that 5-ht5b receptors can specifically interact with 5-HT1A receptors and retain them in endosomal compartments. This interaction reduces 5-HT1A surface expression and is mediated by interactions between the fourth and fifth trans-membrane domain (TMD). This possibly represents a mechanism by which 5-ht5b receptors regulate the activity of other 5-HT receptor.
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Affiliation(s)
- Sabine Niebert
- Department of Maxillofacial Surgery, University Medical CenterGöttingen, Germany
| | - Gijsbert J van Belle
- Institute of Cardiovascular Physiology, University Medical CenterGöttingen, Germany
| | - Steffen Vogelgesang
- Institute of Neuro- and Sensory Physiology, University Medical CenterGöttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University Medical CenterGöttingen, Germany
| | - Till Manzke
- Institute of Neuro- and Sensory Physiology, University Medical CenterGöttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University Medical CenterGöttingen, Germany
| | - Marcus Niebert
- Institute of Neuro- and Sensory Physiology, University Medical CenterGöttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University Medical CenterGöttingen, Germany
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68
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McDonald NA, Lind AL, Smith SE, Li R, Gould KL. Nanoscale architecture of the Schizosaccharomyces pombe contractile ring. eLife 2017; 6:28865. [PMID: 28914606 PMCID: PMC5779233 DOI: 10.7554/elife.28865] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/14/2017] [Indexed: 12/13/2022] Open
Abstract
The contractile ring is a complex molecular apparatus which physically divides many eukaryotic cells. Despite knowledge of its protein composition, the molecular architecture of the ring is not known. Here we have applied super-resolution microscopy and FRET to determine the nanoscale spatial organization of Schizosaccharomyces pombe contractile ring components relative to the plasma membrane. Similar to other membrane-tethered actin structures, we find proteins localize in specific layers relative to the membrane. The most membrane-proximal layer (0–80 nm) is composed of membrane-binding scaffolds, formin, and the tail of the essential myosin-II. An intermediate layer (80–160 nm) consists of a network of cytokinesis accessory proteins as well as multiple signaling components which influence cell division. Farthest from the membrane (160–350 nm) we find F-actin, the motor domains of myosins, and a major F-actin crosslinker. Circumferentially within the ring, multiple proteins proximal to the membrane form clusters of different sizes, while components farther from the membrane are uniformly distributed. This comprehensive organizational map provides a framework for understanding contractile ring function.
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Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Abigail L Lind
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Sarah E Smith
- Stowers Institute for Medical Research, Kansas City, United States
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
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69
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Wottawa M, Naas S, Böttger J, van Belle GJ, Möbius W, Revelo NH, Heidenreich D, von Ahlen M, Zieseniss A, Kröhnert K, Lutz S, Lenz C, Urlaub H, Rizzoli SO, Katschinski DM. Hypoxia-stimulated membrane trafficking requires T-plastin. Acta Physiol (Oxf) 2017; 221:59-73. [PMID: 28218996 DOI: 10.1111/apha.12859] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 12/30/2022]
Abstract
AIM Traffic between the plasma membrane and the endomembrane compartments is an essential feature of eukaryotic cells. The secretory pathway sends cargoes from biosynthetic compartments to the plasma membrane. This is counterbalanced by a retrograde endocytic route and is essential for cell homoeostasis. Cells need to adapt rapidly to environmental challenges such as the reduction of pO2 which, however, has not been analysed in relation to membrane trafficking in detail. Therefore, we determined changes in the plasma membrane trafficking in normoxia, hypoxia, and after reoxygenation. METHODS Membrane trafficking was analysed by using the bulk membrane endocytosis marker FM 1-43, the newly developed membrane probe mCLING, wheat germ agglutinin as well as fluorescently labelled cholera toxin subunit B. Additionally, the uptake of specific membrane proteins was determined. In parallel, a non-biased SILAC screen was performed to analyse the abundance of membrane proteins in normoxia and hypoxia. RESULTS Membrane trafficking was increased in hypoxia and quickly reversed upon reoxygenation. This effect was independent of the hypoxia-inducible factor (HIF) system. Using SILAC technology, we identified that the actin-bundling protein T-plastin is recruited to the plasma membrane in hypoxia. By the use of T-plastin knockdown cells, we could show that T-plastin mediates the hypoxia-induced membrane trafficking, which was associated with an increased actin density in the cells as determined by electron microscopy. CONCLUSION Membrane trafficking is highly dynamic upon hypoxia. This phenotype is quickly reversible upon reoxygenation, which suggests that this mechanism participates in the cellular adaptation to hypoxia.
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Affiliation(s)
- M. Wottawa
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - S. Naas
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - J. Böttger
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - G. J. van Belle
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - W. Möbius
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - N. H. Revelo
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - D. Heidenreich
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - M. von Ahlen
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - A. Zieseniss
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - K. Kröhnert
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - S. Lutz
- Institute of Pharmacology; UMG; Göttingen Germany
| | - C. Lenz
- Bioanalytical Mass Spectrometry; Max Planck Institute for Biophysical Chemistry; Göttingen Germany
- Bioanalytics Research Group; Institute of Clinical Chemistry; UMG; Göttingen Germany
| | - H. Urlaub
- Bioanalytical Mass Spectrometry; Max Planck Institute for Biophysical Chemistry; Göttingen Germany
- Bioanalytics Research Group; Institute of Clinical Chemistry; UMG; Göttingen Germany
| | - S. O. Rizzoli
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - D. M. Katschinski
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
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70
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Wang HY, Sun J, Xia LY, Li YH, Chen Z, Wu FG. Permeabilization-Tolerant Plasma Membrane Imaging Reagent Based on Amine-Rich Glycol Chitosan Derivatives. ACS Biomater Sci Eng 2017; 3:2570-2578. [DOI: 10.1021/acsbiomaterials.7b00448] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hong-Yin Wang
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing 210096, P. R. China
| | - Jie Sun
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing 210096, P. R. China
| | - Liu-Yuan Xia
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing 210096, P. R. China
| | - Yan-Hong Li
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing 210096, P. R. China
| | - Zhan Chen
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Fu-Gen Wu
- State
Key Laboratory of Bioelectronics, School of Biological Science and
Medical Engineering, Southeast University, 2 Sipailou Road, Nanjing 210096, P. R. China
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71
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Sezgin E. Super-resolution optical microscopy for studying membrane structure and dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:273001. [PMID: 28481213 PMCID: PMC5952331 DOI: 10.1088/1361-648x/aa7185] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Investigation of cell membrane structure and dynamics requires high spatial and temporal resolution. The spatial resolution of conventional light microscopy is limited due to the diffraction of light. However, recent developments in microscopy enabled us to access the nano-scale regime spatially, thus to elucidate the nanoscopic structures in the cellular membranes. In this review, we will explain the resolution limit, address the working principles of the most commonly used super-resolution microscopy techniques and summarise their recent applications in the biomembrane field.
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Affiliation(s)
- Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS, United Kingdom
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72
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Measuring synaptic vesicles using cellular electrochemistry and nanoscale molecular imaging. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0048] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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73
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Saimani U, Kim K. Traffic from the endosome towards trans-Golgi network. Eur J Cell Biol 2017; 96:198-205. [PMID: 28256269 DOI: 10.1016/j.ejcb.2017.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/24/2017] [Accepted: 02/16/2017] [Indexed: 11/16/2022] Open
Abstract
Retrograde passage of a transport carrier entails cargo sorting at the endosome, generation of a cargo-laden carrier and its movement along cytoskeletal tracks towards trans-Golgi network (TGN), tethering at the TGN, and fusion with the Golgi membrane. Significant advances have been made in understanding this traffic system, revealing molecular requirements in each step and the functional connection between them as well as biomedical implication of the dysregulation of those important traffic factors. This review focuses on describing up-to-date action mechanisms for retrograde transport from the endosomal system to the TGN.
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Affiliation(s)
- Uma Saimani
- Department of Biology, Missouri State University, 901 S National, Springfield, MO 65807, United States
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National, Springfield, MO 65807, United States.
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74
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Cristino L, Imperatore R, Di Marzo V. Techniques for the Cellular and Subcellular Localization of Endocannabinoid Receptors and Enzymes in the Mammalian Brain. Methods Enzymol 2017; 593:61-98. [DOI: 10.1016/bs.mie.2017.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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75
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Redpath GMI, Sophocleous RA, Turnbull L, Whitchurch CB, Cooper ST. Ferlins Show Tissue-Specific Expression and Segregate as Plasma Membrane/Late Endosomal or Trans-Golgi/Recycling Ferlins. Traffic 2016; 17:245-66. [PMID: 26707827 DOI: 10.1111/tra.12370] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 01/10/2023]
Abstract
Ferlins are a family of transmembrane-anchored vesicle fusion proteins uniquely characterized by 5-7 tandem cytoplasmic C2 domains, Ca(2+)-regulated phospholipid-binding domains that regulate vesicle fusion in the synaptotagmin family. In humans, dysferlin mutations cause limb-girdle muscular dystrophy type 2B (LGMD2B) due to defective Ca(2+)-dependent, vesicle-mediated membrane repair and otoferlin mutations cause non-syndromic deafness due to defective Ca(2+)-triggered auditory neurotransmission. In this study, we describe the tissue-specific expression, subcellular localization and endocytic trafficking of the ferlin family. Studies of endosomal transit together with 3D-structured illumination microscopy reveals dysferlin and myoferlin are abundantly expressed at the PM and cycle to Rab7-positive late endosomes, supporting potential roles in the late-endosomal pathway. In contrast, Fer1L6 shows concentrated localization to a specific compartment of the trans-Golgi/recycling endosome, cycling rapidly between this compartment and the PM via Rab11 recycling endosomes. Otoferlin also shows trans-Golgi to PM cycling, with very low levels of PM otoferlin suggesting either brief PM residence, or rare incorporation of otoferlin molecules into the PM. Thus, type-I and type-II ferlins segregate as PM/late-endosomal or trans-Golgi/recycling ferlins, consistent with different ferlins mediating vesicle fusion events in specific subcellular locations.
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Affiliation(s)
- Gregory M I Redpath
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Reece A Sophocleous
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, Australia
| | - Lynne Turnbull
- Microbial Imaging Facility, The iThree Institute, University of Technology Sydney, Ultimo, Australia
| | - Cynthia B Whitchurch
- Microbial Imaging Facility, The iThree Institute, University of Technology Sydney, Ultimo, Australia
| | - Sandra T Cooper
- Institute for Neuroscience and Muscle Research, Kid's Research Institute, Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
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76
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Strenzke N, Chakrabarti R, Al-Moyed H, Müller A, Hoch G, Pangrsic T, Yamanbaeva G, Lenz C, Pan KT, Auge E, Geiss-Friedlander R, Urlaub H, Brose N, Wichmann C, Reisinger E. Hair cell synaptic dysfunction, auditory fatigue and thermal sensitivity in otoferlin Ile515Thr mutants. EMBO J 2016; 35:2519-2535. [PMID: 27729456 DOI: 10.15252/embj.201694564] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/24/2016] [Accepted: 09/13/2016] [Indexed: 11/09/2022] Open
Abstract
The multi-C2 domain protein otoferlin is required for hearing and mutated in human deafness. Some OTOF mutations cause a mild elevation of auditory thresholds but strong impairment of speech perception. At elevated body temperature, hearing is lost. Mice homozygous for one of these mutations, OtofI515T/I515T, exhibit a moderate hearing impairment involving enhanced adaptation to continuous or repetitive sound stimulation. In OtofI515T/I515T inner hair cells (IHCs), otoferlin levels are diminished by 65%, and synaptic vesicles are enlarged. Exocytosis during prolonged stimulation is strongly reduced. This indicates that otoferlin is critical for the reformation of properly sized and fusion-competent synaptic vesicles. Moreover, we found sustained exocytosis and sound encoding to scale with the amount of otoferlin at the plasma membrane. We identified a 20 amino acid motif including an RXR motif, presumably present in human but not in mouse otoferlin, which reduces the plasma membrane abundance of Ile515Thr-otoferlin. Together, this likely explains the auditory synaptopathy at normal temperature and the temperature-sensitive deafness in humans carrying the Ile515Thr mutation.
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Affiliation(s)
- Nicola Strenzke
- Auditory Systems Physiology Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany .,Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany
| | - Rituparna Chakrabarti
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Hanan Al-Moyed
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany.,Molecular Biology of Cochlear Neurotransmission Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Alexandra Müller
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany.,Molecular Biology of Cochlear Neurotransmission Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Gerhard Hoch
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and German Primate Center, Göttingen, Germany
| | - Tina Pangrsic
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Gulnara Yamanbaeva
- Auditory Systems Physiology Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Kuan-Ting Pan
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Elisabeth Auge
- Auditory Systems Physiology Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Ruth Geiss-Friedlander
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Brose
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Carolin Wichmann
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany .,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ellen Reisinger
- Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany .,Molecular Biology of Cochlear Neurotransmission Group, Department for Otolaryngology and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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77
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Duan G, Hu W, Wang J. Research on the natural image super-resolution reconstruction algorithm based on compressive perception theory and deep learning model. Neurocomputing 2016. [DOI: 10.1016/j.neucom.2015.12.125] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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78
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Stanly TA, Fritzsche M, Banerji S, García E, Bernardino de la Serna J, Jackson DG, Eggeling C. Critical importance of appropriate fixation conditions for faithful imaging of receptor microclusters. Biol Open 2016; 5:1343-50. [PMID: 27464671 PMCID: PMC5051640 DOI: 10.1242/bio.019943] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Receptor clustering is known to trigger signalling events that contribute to critical changes in cellular functions. Faithful imaging of such clusters by means of fluorescence microscopy relies on the application of adequate cell fixation methods prior to immunolabelling in order to avoid artefactual redistribution by the antibodies themselves. Previous work has highlighted the inadequacy of fixation with paraformaldehyde (PFA) alone for efficient immobilisation of membrane-associated molecules, and the advantages of fixation with PFA in combination with glutaraldehyde (GA). Using fluorescence microscopy, we here highlight how inadequate fixation can lead to the formation of artefactual clustering of receptors in lymphatic endothelial cells, focussing on the transmembrane hyaluronan receptors LYVE-1 and CD44, and the homotypic adhesion molecule CD31, each of which displays their native diffuse surface distribution pattern only when visualised with the right fixation techniques, i.e. PFA/GA in combination. Fluorescence recovery after photobleaching (FRAP) confirms that the artefactual receptor clusters are indeed introduced by residual mobility. In contrast, we observed full immobilisation of membrane proteins in cells that were fixed and then subsequently permeabilised, irrespective of whether the fixative was PFA or PFA/GA in combination. Our study underlines the importance of choosing appropriate sample preparation protocols for preserving authentic receptor organisation in advanced fluorescence microscopy. Summary: Commonly used fixation protocols during immunolabelling can result in artefactual protein distribution. We highlight the artefacts in images and provide fixation conditions for studying membrane receptor organisation.
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Affiliation(s)
- Tess A Stanly
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Marco Fritzsche
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Suneale Banerji
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Esther García
- Wolfson Imaging Centre, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Jorge Bernardino de la Serna
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK Science & Technology Facilities Council, Rutherford Appleton Laboratory, Central Laser Facility, Research Complex at Harwell, Harwell-Oxford Campus, Oxford OX11 0FA, UK
| | - David G Jackson
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK Wolfson Imaging Centre, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
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79
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From single molecules to life: microscopy at the nanoscale. Anal Bioanal Chem 2016; 408:6885-911. [PMID: 27613013 PMCID: PMC5566169 DOI: 10.1007/s00216-016-9781-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/30/2016] [Accepted: 07/07/2016] [Indexed: 01/08/2023]
Abstract
Super-resolution microscopy is the term commonly given to fluorescence microscopy techniques with resolutions that are not limited by the diffraction of light. Since their conception a little over a decade ago, these techniques have quickly become the method of choice for many biologists studying structures and processes of single cells at the nanoscale. In this review, we present the three main approaches used to tackle the diffraction barrier of ∼200 nm: stimulated-emission depletion (STED) microscopy, structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM). We first present a theoretical overview of the techniques and underlying physics, followed by a practical guide to all of the facets involved in designing a super-resolution experiment, including an approachable explanation of the photochemistry involved, labeling methods available, and sample preparation procedures. Finally, we highlight some of the most exciting recent applications of and developments in these techniques, and discuss the outlook for this field. Super-resolution microscopy techniques. Working principles of the common approaches stimulated-emission depletion (STED) microscopy, structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM). ![]()
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80
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Watanabe S. Flash-and-Freeze: Coordinating Optogenetic Stimulation with Rapid Freezing to Visualize Membrane Dynamics at Synapses with Millisecond Resolution. Front Synaptic Neurosci 2016; 8:24. [PMID: 27594835 PMCID: PMC4990539 DOI: 10.3389/fnsyn.2016.00024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/03/2016] [Indexed: 01/12/2023] Open
Abstract
Electron microscopy depicts subcellular structures at synapses exquisitely but only captures static images. To visualize membrane dynamics, we have developed a novel technique, called flash-and-freeze, which induces neuronal activity with a flash of light and captures the membrane dynamics by rapid freezing. For characterizing membrane movements during synaptic transmission, a light-sensitive cation channel, channelrhodopsin, is heterologously expressed in mouse hippocampal neurons or in Caenorhabditis elegans motor neurons. A brief pulse of blue light activates channelrhodopsin and induces an action potential, leading to synaptic transmission. Following the light stimulation, neurons are frozen at different time intervals ranging from 10 ms to 20 s. Electron micrographs are then acquired from each time point to visualize the morphological changes. Using this approach, we have characterized a novel form of endocytosis, ultrafast endocytosis, which rapidly removes excess membrane added to the surface during neurotransmission. The flash-and-freeze approach can be adapted to study other cellular phenomena that can be induced by light-sensitive genetic or pharmacological tools.
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Affiliation(s)
- Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins UniversityBaltimore, MD, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimore, MD, USA
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81
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Modes and mechanisms of synaptic vesicle recycling. Curr Opin Neurobiol 2016; 39:17-23. [DOI: 10.1016/j.conb.2016.03.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/02/2016] [Accepted: 03/07/2016] [Indexed: 11/30/2022]
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82
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Vogl C, Panou I, Yamanbaeva G, Wichmann C, Mangosing SJ, Vilardi F, Indzhykulian AA, Pangršič T, Santarelli R, Rodriguez-Ballesteros M, Weber T, Jung S, Cardenas E, Wu X, Wojcik SM, Kwan KY, Del Castillo I, Schwappach B, Strenzke N, Corey DP, Lin SY, Moser T. Tryptophan-rich basic protein (WRB) mediates insertion of the tail-anchored protein otoferlin and is required for hair cell exocytosis and hearing. EMBO J 2016; 35:2536-2552. [PMID: 27458190 DOI: 10.15252/embj.201593565] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/29/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022] Open
Abstract
The transmembrane recognition complex (TRC40) pathway mediates the insertion of tail-anchored (TA) proteins into membranes. Here, we demonstrate that otoferlin, a TA protein essential for hair cell exocytosis, is inserted into the endoplasmic reticulum (ER) via the TRC40 pathway. We mutated the TRC40 receptor tryptophan-rich basic protein (Wrb) in hair cells of zebrafish and mice and studied the impact of defective TA protein insertion. Wrb disruption reduced otoferlin levels in hair cells and impaired hearing, which could be restored in zebrafish by transgenic Wrb rescue and otoferlin overexpression. Wrb-deficient mouse inner hair cells (IHCs) displayed normal numbers of afferent synapses, Ca2+ channels, and membrane-proximal vesicles, but contained fewer ribbon-associated vesicles. Patch-clamp of IHCs revealed impaired synaptic vesicle replenishment. In vivo recordings from postsynaptic spiral ganglion neurons showed a use-dependent reduction in sound-evoked spiking, corroborating the notion of impaired IHC vesicle replenishment. A human mutation affecting the transmembrane domain of otoferlin impaired its ER targeting and caused an auditory synaptopathy. We conclude that the TRC40 pathway is critical for hearing and propose that otoferlin is an essential substrate of this pathway in hair cells.
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Affiliation(s)
- Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Iliana Panou
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Gulnara Yamanbaeva
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - Carolin Wichmann
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sara J Mangosing
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Fabio Vilardi
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Artur A Indzhykulian
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tina Pangršič
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Physiology of Mammalian Vestibular Hair Cells Junior Research Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Rosamaria Santarelli
- Department of Neurosciences, University of Padova, Padova, Italy.,Audiology and Phoniatrics Service, Treviso Regional Hospital, Treviso, Italy
| | | | - Thomas Weber
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sangyong Jung
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Elena Cardenas
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Xudong Wu
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Kelvin Y Kwan
- W. M. Keck Center for Collaborative Neuroscience, Nelson Lab-D250, Rutgers University, Piscataway, NJ, USA
| | - Ignacio Del Castillo
- Servicio de Genetica, Hospital Universitario Ramon y Cajal, IRYCIS, Madrid, Spain.,Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Blanche Schwappach
- Institute of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Nicola Strenzke
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Auditory Systems Physiology Group and InnerEarLab, Department of Otolaryngology, University of Göttingen Medical Center, Göttingen, Germany
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Shuh-Yow Lin
- Otolaryngology Division, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany .,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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83
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Zhao WD, Hamid E, Shin W, Wen PJ, Krystofiak ES, Villarreal SA, Chiang HC, Kachar B, Wu LG. Hemi-fused structure mediates and controls fusion and fission in live cells. Nature 2016; 534:548-52. [PMID: 27309816 PMCID: PMC4930626 DOI: 10.1038/nature18598] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 05/24/2016] [Indexed: 11/09/2022]
Abstract
Membrane fusion and fission are vital for eukaryotic life. For three decades, it has been proposed that fusion is mediated by fusion between the proximal leaflets of two bilayers (hemi-fusion) to produce a hemi-fused structure, followed by fusion between the distal leaflets, whereas fission is via hemi-fission, which also produces a hemi-fused structure, followed by full fission. This hypothesis remained unsupported owing to the lack of observation of hemi-fusion or hemi-fission in live cells. A competing fusion hypothesis involving protein-lined pore formation has also been proposed. Here we report the observation of a hemi-fused Ω-shaped structure in live neuroendocrine chromaffin cells and pancreatic β-cells, visualized using confocal and super-resolution stimulated emission depletion microscopy. This structure is generated from fusion pore opening or closure (fission) at the plasma membrane. Unexpectedly, the transition to full fusion or fission is determined by competition between fusion and calcium/dynamin-dependent fission mechanisms, and is notably slow (seconds to tens of seconds) in a substantial fraction of the events. These results provide key missing evidence in support of the hemi-fusion and hemi-fission hypothesis in live cells, and reveal the hemi-fused intermediate as a key structure controlling fusion and fission, as fusion and fission mechanisms compete to determine the transition to fusion or fission.
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Affiliation(s)
- Wei-Dong Zhao
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Edaeni Hamid
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Wonchul Shin
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Peter J Wen
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Evan S Krystofiak
- National Institute on Deafness and other Communication Disorders, 35A Convent Drive, Room 3D-824, Bethesda, Maryland 20892, USA
| | - Seth A Villarreal
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Hsueh-Cheng Chiang
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
| | - Bechara Kachar
- National Institute on Deafness and other Communication Disorders, 35A Convent Drive, Room 3D-824, Bethesda, Maryland 20892, USA
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Drive, Room 2B-1012, Bethesda, Maryland 20892, USA
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84
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Chen Y, Gu M, Gunning PW, Russell SM. Dense small molecule labeling enables activator-dependent STORM by proximity mapping. Histochem Cell Biol 2016; 146:255-66. [PMID: 27246003 DOI: 10.1007/s00418-016-1451-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2016] [Indexed: 12/18/2022]
Abstract
Stochastic optical reconstruction microscopy (STORM) enables high-resolution imaging, but multi-channel 3D imaging is problematic because of chromatic aberrations and alignment errors. The use of activator-dependent STORM in which spectrally distinct activators can be coupled with a single reporter can circumvent such issues. However, the standard approach of linking activators and reporters to a single antibody molecule is hampered by low labeling density and the large size of the antibody. We proposed that small molecule labels might enable activator-dependent STORM if the reporter or activator were linked to separate small molecules that bound within 3.5 nm of each other. This would greatly increase the labeling density and therefore improve resolution. We tested various mixtures of phalloidin- or mCling-conjugated fluorophore to demonstrate this feasibility. The specific activation was dependent on the choice of activator, its density, a matching activating laser and its power. In addition to providing an effective means of multi-channel 3D STORM imaging, this method also provides information about the local proximity between labels, potentially enabling super-resolved mapping of the conformation of the labeled structures.
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Affiliation(s)
- Ye Chen
- Immune Signalling Laboratory, Peter MacCallum Cancer Centre, East Melbourne, VIC, Australia.,Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Min Gu
- Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia.,Artificial-Intelligence Nanophotonics Laboratory, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Peter W Gunning
- School of Medical Sciences, UNSW Australia, Sydney, NSW, 2052, Australia
| | - Sarah M Russell
- Immune Signalling Laboratory, Peter MacCallum Cancer Centre, East Melbourne, VIC, Australia. .,Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia. .,Department of Pathology, The University of Melbourne, Parkville, VIC, Australia. .,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC, Australia.
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85
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Naganbabu M, Perkins LA, Wang Y, Kurish J, Schmidt BF, Bruchez MP. Multiexcitation Fluorogenic Labeling of Surface, Intracellular, and Total Protein Pools in Living Cells. Bioconjug Chem 2016; 27:1525-31. [PMID: 27159569 PMCID: PMC4911959 DOI: 10.1021/acs.bioconjchem.6b00169] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
![]()
Malachite
green (MG) is a fluorogenic dye that shows fluorescence enhancement
upon binding to its engineered cognate protein, a fluorogen activating
protein (FAP). Energy transfer donors such as cyanine and rhodamine
dyes have been conjugated with MG to modify the spectral properties
of the fluorescent complexes, where the donor dyes transfer energy
through Förster resonance energy transfer to the MG complex
resulting in binding-conditional fluorescence emission in the far-red
region. In this article, we use a violet-excitable dye as a donor
to sensitize the far-red emission of the MG-FAP complex. Two blue
emitting fluorescent coumarin dyes were coupled to MG and evaluated
for energy transfer to the MG-FAP complex via its secondary excitation
band. 6,8-Difluoro-7-hydroxycoumarin-3-carboxylic acid (Pacific blue,
PB) showed the most efficient energy transfer and maximum brightness
in the far-red region upon violet (405 nm) excitation. These blue-red
(BluR) tandem dyes are spectrally varied from other tandem dyes and
are able to produce fluorescence images of the MG-FAP complex with
a large Stokes shift (>250 nm). These dyes are cell-permeable and
are used to label intracellular proteins. Used together with a cell-impermeable
hexa-Cy3-MG (HCM) dye that labels extracellular proteins, we are able
to visualize extracellular, intracellular, and total pools of cellular
protein using one fluorogenic tag that combines with distinct dyes
to effect different spectral characteristics.
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Affiliation(s)
- Matharishwan Naganbabu
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
| | - Lydia A Perkins
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
| | - Yi Wang
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
| | - Jeffery Kurish
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
| | - Brigitte F Schmidt
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
| | - Marcel P Bruchez
- Department of Chemistry, ‡Department of Biological Sciences, and §Molecular Biosensors and Imaging Center, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, Pennsylvania, United States
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86
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Gazit N, Vertkin I, Shapira I, Helm M, Slomowitz E, Sheiba M, Mor Y, Rizzoli S, Slutsky I. IGF-1 Receptor Differentially Regulates Spontaneous and Evoked Transmission via Mitochondria at Hippocampal Synapses. Neuron 2016; 89:583-97. [PMID: 26804996 PMCID: PMC4742535 DOI: 10.1016/j.neuron.2015.12.034] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 11/19/2015] [Accepted: 12/13/2015] [Indexed: 12/22/2022]
Abstract
The insulin-like growth factor-1 receptor (IGF-1R) signaling is a key regulator of lifespan, growth, and development. While reduced IGF-1R signaling delays aging and Alzheimer's disease progression, whether and how it regulates information processing at central synapses remains elusive. Here, we show that presynaptic IGF-1Rs are basally active, regulating synaptic vesicle release and short-term plasticity in excitatory hippocampal neurons. Acute IGF-1R blockade or transient knockdown suppresses spike-evoked synaptic transmission and presynaptic cytosolic Ca(2+) transients, while promoting spontaneous transmission and resting Ca(2+) level. This dual effect on transmitter release is mediated by mitochondria that attenuate Ca(2+) buffering in the absence of spikes and decrease ATP production during spiking activity. We conclude that the mitochondria, activated by IGF-1R signaling, constitute a critical regulator of information processing in hippocampal neurons by maintaining evoked-to-spontaneous transmission ratio, while constraining synaptic facilitation at high frequencies. Excessive IGF-1R tone may contribute to hippocampal hyperactivity associated with Alzheimer's disease.
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Affiliation(s)
- Neta Gazit
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Irena Vertkin
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ilana Shapira
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Martin Helm
- Department of Neuro- and Sensory Physiology, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, European Neuroscience Institute, University of Göttingen Medical Center, 37075 Göttingen, Germany; International Max Planck Research School Molecular Biology, 37077 Göttingen, Germany
| | - Edden Slomowitz
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Maayan Sheiba
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Yael Mor
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Silvio Rizzoli
- Department of Neuro- and Sensory Physiology, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, European Neuroscience Institute, University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel.
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87
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Revelo NH, Rizzoli SO. The Membrane Marker mCLING Reveals the Molecular Composition of Trafficking Organelles. ACTA ACUST UNITED AC 2016; 74:2.25.1-2.25.21. [PMID: 26729031 DOI: 10.1002/0471142301.ns0225s74] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
mCLING is a fixable endocytosis marker that can be combined with immunolabeling techniques to study the molecular composition of trafficking organelles. mCLING can be used both in cultured cells and in tissue if critical sample preparation steps, such as fixation, are correctly performed. This unit describes protocols for the application of mCLING and for the subsequent sample processing. We include immunostaining protocols and embedding procedures for confocal and high-resolution microscopy.
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Affiliation(s)
- Natalia H Revelo
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen.,Department of Tumor Immunology, Institute for Molecular Life Sciences, Radboud University Medical Center
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen
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88
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Crawford DC, Kavalali ET. Molecular underpinnings of synaptic vesicle pool heterogeneity. Traffic 2015; 16:338-64. [PMID: 25620674 DOI: 10.1111/tra.12262] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/06/2015] [Indexed: 12/31/2022]
Abstract
Neuronal communication relies on chemical synaptic transmission for information transfer and processing. Chemical neurotransmission is initiated by synaptic vesicle fusion with the presynaptic active zone resulting in release of neurotransmitters. Classical models have assumed that all synaptic vesicles within a synapse have the same potential to fuse under different functional contexts. In this model, functional differences among synaptic vesicle populations are ascribed to their spatial distribution in the synapse with respect to the active zone. Emerging evidence suggests, however, that synaptic vesicles are not a homogenous population of organelles, and they possess intrinsic molecular differences and differential interaction partners. Recent studies have reported a diverse array of synaptic molecules that selectively regulate synaptic vesicles' ability to fuse synchronously and asynchronously in response to action potentials or spontaneously irrespective of action potentials. Here we discuss these molecular mediators of vesicle pool heterogeneity that are found on the synaptic vesicle membrane, on the presynaptic plasma membrane, or within the cytosol and consider some of the functional consequences of this diversity. This emerging molecular framework presents novel avenues to probe synaptic function and uncover how synaptic vesicle pools impact neuronal signaling.
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Affiliation(s)
- Devon C Crawford
- Department of Neuroscience, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
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89
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Jung S, Maritzen T, Wichmann C, Jing Z, Neef A, Revelo NH, Al-Moyed H, Meese S, Wojcik SM, Panou I, Bulut H, Schu P, Ficner R, Reisinger E, Rizzoli SO, Neef J, Strenzke N, Haucke V, Moser T. Disruption of adaptor protein 2μ (AP-2μ) in cochlear hair cells impairs vesicle reloading of synaptic release sites and hearing. EMBO J 2015; 34:2686-702. [PMID: 26446278 DOI: 10.15252/embj.201591885] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/04/2015] [Indexed: 11/09/2022] Open
Abstract
Active zones (AZs) of inner hair cells (IHCs) indefatigably release hundreds of vesicles per second, requiring each release site to reload vesicles at tens per second. Here, we report that the endocytic adaptor protein 2μ (AP-2μ) is required for release site replenishment and hearing. We show that hair cell-specific disruption of AP-2μ slows IHC exocytosis immediately after fusion of the readily releasable pool of vesicles, despite normal abundance of membrane-proximal vesicles and intact endocytic membrane retrieval. Sound-driven postsynaptic spiking was reduced in a use-dependent manner, and the altered interspike interval statistics suggested a slowed reloading of release sites. Sustained strong stimulation led to accumulation of endosome-like vacuoles, fewer clathrin-coated endocytic intermediates, and vesicle depletion of the membrane-distal synaptic ribbon in AP-2μ-deficient IHCs, indicating a further role of AP-2μ in clathrin-dependent vesicle reformation on a timescale of many seconds. Finally, we show that AP-2 sorts its IHC-cargo otoferlin. We propose that binding of AP-2 to otoferlin facilitates replenishment of release sites, for example, via speeding AZ clearance of exocytosed material, in addition to a role of AP-2 in synaptic vesicle reformation.
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Affiliation(s)
- SangYong Jung
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Tanja Maritzen
- Leibniz Institut für Molekulare Pharmakologie (FMP), Berlin, Germany NeuroCure Cluster of Excellence & Collaborative Research Center 958, Freie Universität Berlin, Berlin, Germany
| | - Carolin Wichmann
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Zhizi Jing
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Auditory Systems Physiology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Andreas Neef
- Bernstein Group Biophysics of Neural Computation, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Natalia H Revelo
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Hanan Al-Moyed
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Sandra Meese
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Department of Molecular Structural Biology, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Iliana Panou
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Haydar Bulut
- Leibniz Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Peter Schu
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Department of Molecular Structural Biology, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Ellen Reisinger
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Molecular Biology of Cochlear Neurotransmission Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Silvio O Rizzoli
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
| | - Jakob Neef
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Nicola Strenzke
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Auditory Systems Physiology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Volker Haucke
- Leibniz Institut für Molekulare Pharmakologie (FMP), Berlin, Germany NeuroCure Cluster of Excellence & Collaborative Research Center 958, Freie Universität Berlin, Berlin, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany Collaborative Research Center 889, University of Göttingen, Göttingen, Germany Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
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90
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Wichmann C. Molecularly and structurally distinct synapses mediate reliable encoding and processing of auditory information. Hear Res 2015; 330:178-90. [PMID: 26188105 DOI: 10.1016/j.heares.2015.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/21/2015] [Accepted: 07/10/2015] [Indexed: 01/20/2023]
Abstract
Hearing impairment is the most common human sensory deficit. Considering the sophisticated anatomy and physiology of the auditory system, disease-related failures frequently occur. To meet the demands of the neuronal circuits responsible for processing auditory information, the synapses of the lower auditory pathway are anatomically and functionally specialized to process acoustic information indefatigably with utmost temporal precision. Despite sharing some functional properties, the afferent synapses of the cochlea and of auditory brainstem differ greatly in their morphology and employ distinct molecular mechanisms for regulating synaptic vesicle release. Calyceal synapses of the endbulb of Held and the calyx of Held profit from a large number of release sites that project onto one principal cell. Cochlear inner hair cell ribbon synapses exhibit a unique one-to-one relation of the presynaptic active zone to the postsynaptic cell and use hair-cell-specific proteins such as otoferlin for vesicle release. The understanding of the molecular physiology of the hair cell ribbon synapse has been advanced by human genetics studies of sensorineural hearing impairment, revealing human auditory synaptopathy as a new nosological entity.
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Affiliation(s)
- Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience & InnerEarLab, University Medical Center, Göttingen, Germany.
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91
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The structure and function of presynaptic endosomes. Exp Cell Res 2015; 335:172-9. [DOI: 10.1016/j.yexcr.2015.04.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 04/23/2015] [Indexed: 11/19/2022]
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92
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Wichmann C, Moser T. Relating structure and function of inner hair cell ribbon synapses. Cell Tissue Res 2015; 361:95-114. [PMID: 25874597 PMCID: PMC4487357 DOI: 10.1007/s00441-014-2102-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/18/2014] [Indexed: 01/28/2023]
Abstract
In the mammalian cochlea, sound is encoded at synapses between inner hair cells (IHCs) and type I spiral ganglion neurons (SGNs). Each SGN receives input from a single IHC ribbon-type active zone (AZ) and yet SGNs indefatigably spike up to hundreds of Hz to encode acoustic stimuli with submillisecond precision. Accumulating evidence indicates a highly specialized molecular composition and structure of the presynapse, adapted to suit these high functional demands. However, we are only beginning to understand key features such as stimulus-secretion coupling, exocytosis mechanisms, exo-endocytosis coupling, modes of endocytosis and vesicle reformation, as well as replenishment of the readily releasable pool. Relating structure and function has become an important avenue in addressing these points and has been applied to normal and genetically manipulated hair cell synapses. Here, we review some of the exciting new insights gained from recent studies of the molecular anatomy and physiology of IHC ribbon synapses.
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Affiliation(s)
- C. Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University Medical Center Göttingen, Göttingen, Germany
| | - T. Moser
- Collaborative Research Center 889, University Medical Center Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany
- Bernstein Center for Computational Neuroscience, University of Göttingen, Göttingen, Germany
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93
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Pech U, Revelo NH, Seitz KJ, Rizzoli SO, Fiala A. Optical dissection of experience-dependent pre- and postsynaptic plasticity in the Drosophila brain. Cell Rep 2015; 10:2083-95. [PMID: 25818295 DOI: 10.1016/j.celrep.2015.02.065] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/24/2015] [Accepted: 02/26/2015] [Indexed: 01/18/2023] Open
Abstract
Drosophila represents a key model organism for dissecting neuronal circuits that underlie innate and adaptive behavior. However, this task is limited by a lack of tools to monitor physiological parameters of spatially distributed, central synapses in identified neurons. We generated transgenic fly strains that express functional fluorescent reporters targeted to either pre- or postsynaptic compartments. Presynaptic Ca(2+) dynamics are monitored using synaptophysin-coupled GCaMP3, synaptic transmission is monitored using red fluorescent synaptophysin-pHTomato, and postsynaptic Ca(2+) dynamics are visualized using GCaMP3 fused with the postsynaptic matrix protein, dHomer. Using two-photon in vivo imaging of olfactory projection neurons, odor-evoked activity across populations of synapses is visualized in the antennal lobe and the mushroom body calyx. Prolonged odor exposure causes odor-specific and differential experience-dependent changes in pre- and postsynaptic activity at both levels of olfactory processing. The approach advances the physiological analysis of synaptic connections across defined groups of neurons in intact Drosophila.
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Affiliation(s)
- Ulrike Pech
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Natalia H Revelo
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Humboldtallee 23, 37073 Göttingen, Germany
| | - Katharina J Seitz
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Humboldtallee 23, 37073 Göttingen, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Humboldtallee 23, 37073 Göttingen, Germany
| | - André Fiala
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany.
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94
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Synaptic vesicle pools: Principles, properties and limitations. Exp Cell Res 2015; 335:150-6. [PMID: 25814361 DOI: 10.1016/j.yexcr.2015.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/14/2015] [Indexed: 11/21/2022]
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95
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MacGillavry HD, Hoogenraad CC. The internal architecture of dendritic spines revealed by super-resolution imaging: What did we learn so far? Exp Cell Res 2015; 335:180-6. [PMID: 25746722 DOI: 10.1016/j.yexcr.2015.02.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/26/2015] [Indexed: 12/21/2022]
Abstract
The molecular architecture of dendritic spines defines the efficiency of signal transmission across excitatory synapses. It is therefore critical to understand the mechanisms that control the dynamic localization of the molecular constituents within spines. However, because of the small scale at which most processes within spines take place, conventional light microscopy techniques are not adequate to provide the necessary level of resolution. Recently, super-resolution imaging techniques have overcome the classical barrier imposed by the diffraction of light, and can now resolve the localization and dynamic behavior of proteins within small compartments with nanometer precision, revolutionizing the study of dendritic spine architecture. Here, we highlight exciting new findings from recent super-resolution studies on neuronal spines, and discuss how these studies revealed important new insights into how protein complexes are assembled and how their dynamic behavior shapes the efficiency of synaptic transmission.
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Affiliation(s)
- Harold D MacGillavry
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
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96
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Abstract
Fast synaptic communication in the brain requires synchronous vesicle fusion that is evoked by action potential-induced Ca(2+) influx. However, synaptic terminals also release neurotransmitters by spontaneous vesicle fusion, which is independent of presynaptic action potentials. A functional role for spontaneous neurotransmitter release events in the regulation of synaptic plasticity and homeostasis, as well as the regulation of certain behaviours, has been reported. In addition, there is evidence that the presynaptic mechanisms underlying spontaneous release of neurotransmitters and their postsynaptic targets are segregated from those of evoked neurotransmission. These findings challenge current assumptions about neuronal signalling and neurotransmission, as they indicate that spontaneous neurotransmission has an autonomous role in interneuronal communication that is distinct from that of evoked release.
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97
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Kononenko N, Haucke V. Molecular Mechanisms of Presynaptic Membrane Retrieval and Synaptic Vesicle Reformation. Neuron 2015; 85:484-96. [DOI: 10.1016/j.neuron.2014.12.016] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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98
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Fornasiero EF, Opazo F. Super-resolution imaging for cell biologists: concepts, applications, current challenges and developments. Bioessays 2015; 37:436-51. [PMID: 25581819 DOI: 10.1002/bies.201400170] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The recent 2014 Nobel Prize in chemistry honored an era of discoveries and technical advancements in the field of super-resolution microscopy. However, the applications of diffraction-unlimited imaging in biology have a long road ahead and persistently engage scientists with new challenges. Some of the bottlenecks that restrain the dissemination of super-resolution techniques are tangible, and include the limited performance of affinity probes and the yet not capillary diffusion of imaging setups. Likewise, super-resolution microscopy has introduced new paradigms in the design of projects that require imaging with nanometer-resolution and in the interpretation of biological images. Besides structural or morphological characterization, super-resolution imaging is quickly expanding towards interaction mapping, multiple target detection and live imaging. Here we review the recent progress of biologists employing super-resolution imaging, some pitfalls, implications and new trends, with the purpose of animating the field and spurring future developments.
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Affiliation(s)
- Eugenio F Fornasiero
- STED Microscopy Group, European Neuroscience Institute, Göttingen, Germany; Department of Neuro- and Sensory-physiology, University of Göttingen, Göttingen, Germany
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Truckenbrodt S, Rizzoli SO. Spontaneous vesicle recycling in the synaptic bouton. Front Cell Neurosci 2014; 8:409. [PMID: 25538561 PMCID: PMC4259163 DOI: 10.3389/fncel.2014.00409] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/11/2014] [Indexed: 11/13/2022] Open
Abstract
The trigger for synaptic vesicle exocytosis is Ca2+, which enters the synaptic bouton following action potential stimulation. However, spontaneous release of neurotransmitter also occurs in the absence of stimulation in virtually all synaptic boutons. It has long been thought that this represents exocytosis driven by fluctuations in local Ca2+ levels. The vesicles responding to these fluctuations are thought to be the same ones that release upon stimulation, albeit potentially triggered by different Ca2+ sensors. This view has been challenged by several recent works, which have suggested that spontaneous release is driven by a separate pool of synaptic vesicles. Numerous articles appeared during the last few years in support of each of these hypotheses, and it has been challenging to bring them into accord. We speculate here on the origins of this controversy, and propose a solution that is related to developmental effects. Constitutive membrane traffic, needed for the biogenesis of vesicles and synapses, is responsible for high levels of spontaneous membrane fusion in young neurons, probably independent of Ca2+. The vesicles releasing spontaneously in such neurons are not related to other synaptic vesicle pools and may represent constitutively releasing vesicles (CRVs) rather than bona fide synaptic vesicles. In mature neurons, constitutive traffic is much dampened, and the few remaining spontaneous release events probably represent bona fide spontaneously releasing synaptic vesicles (SRSVs) responding to Ca2+ fluctuations, along with a handful of CRVs that participate in synaptic vesicle turnover.
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Affiliation(s)
- Sven Truckenbrodt
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, European Neuroscience Institute, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain Göttingen, Germany ; International Max Planck Research School for Molecular Biology Göttingen, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, European Neuroscience Institute, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain Göttingen, Germany
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