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Hepburn I, Lallouette J, Chen W, Gallimore AR, Nagasawa-Soeda SY, De Schutter E. Vesicle and reaction-diffusion hybrid modeling with STEPS. Commun Biol 2024; 7:573. [PMID: 38750123 PMCID: PMC11096338 DOI: 10.1038/s42003-024-06276-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 05/01/2024] [Indexed: 05/18/2024] Open
Abstract
Vesicles carry out many essential functions within cells through the processes of endocytosis, exocytosis, and passive and active transport. This includes transporting and delivering molecules between different parts of the cell, and storing and releasing neurotransmitters in neurons. To date, computational simulation of these key biological players has been rather limited and has not advanced at the same pace as other aspects of cell modeling, restricting the realism of computational models. We describe a general vesicle modeling tool that has been designed for wide application to a variety of cell models, implemented within our software STochastic Engine for Pathway Simulation (STEPS), a stochastic reaction-diffusion simulator that supports realistic reconstructions of cell tissue in tetrahedral meshes. The implementation is validated in an extensive test suite, parallel performance is demonstrated in a realistic synaptic bouton model, and example models are visualized in a Blender extension module.
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Affiliation(s)
- Iain Hepburn
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Jules Lallouette
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Weiliang Chen
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Andrew R Gallimore
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Sarah Y Nagasawa-Soeda
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan
| | - Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, Japan.
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2
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Runwal GM, Edwards RH. The role of α-synuclein in exocytosis. Exp Neurol 2024; 373:114668. [PMID: 38147972 DOI: 10.1016/j.expneurol.2023.114668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/28/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
The pathogenesis of degeneration in Parkinson's disease (PD) remains poorly understood but multiple lines of evidence have converged on the presynaptic protein α-synuclein (αsyn). αSyn has been shown to regulate several cellular processes, however, its normal function remains poorly understood. In this review, we will specifically focus on its role in exocytosis.
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Affiliation(s)
- Gautam M Runwal
- Departments of Neurology and Physiology, UCSF School of Medicine, United States of America; Departments of Neurology and Physiology, UCSF School of Medicine, United States of America- Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, MD 20815, United States of America
| | - Robert H Edwards
- Departments of Neurology and Physiology, UCSF School of Medicine, United States of America; Departments of Neurology and Physiology, UCSF School of Medicine, United States of America- Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, MD 20815, United States of America.
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3
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Guo N, Yu L. SIP30 involvement in vesicle exocytosis from PC12 cells. Biochem Biophys Rep 2024; 37:101614. [PMID: 38188363 PMCID: PMC10770524 DOI: 10.1016/j.bbrep.2023.101614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 01/09/2024] Open
Abstract
SNAP25 (synaptosome-associated protein of 25 kDa) is a core SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) protein; and the interaction between SNAP25 and other SNARE proteins is essential for synaptic vesicle exocytosis. Identified as a SNAP25 interacting protein, SIP30 (SNAP25 interacting protein at 30 kDa) has been shown to modulate neuropathic pain behavior, and is potentially involved in the cellular process of vesicle exocytosis. Previous study demonstrated that using a vesicle secretion assay in PC12 cells, anti-SIP30 siRNA reduced vesicle exocytosis. We investigated vesicle exocytosis from PC12 cells with FM1-43 fluorescence dye, and demonstrated that anti-SIP30 siRNA reduced the pool of releasable vesicles and the rate of vesicle exocytosis, without affecting the endocytosis and recycling of the exocytosed vesicles. The results show that SIP30 is involved in vesicle exocytosis, suggesting a potential mechanism of SIP30 modulation of neuropathic pain.
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Affiliation(s)
- Ning Guo
- Department of Genetics, and Center of Alcohol & Substance Use Studies, Rutgers University, Piscataway, NJ, 08854, USA
| | - Lei Yu
- Department of Genetics, and Center of Alcohol & Substance Use Studies, Rutgers University, Piscataway, NJ, 08854, USA
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4
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Kalam SN, Dowland S, Lindsay L, Murphy CR. Porosomes in uterine epithelial cells: Ultrastructural identification and characterization during early pregnancy. J Morphol 2022; 283:1381-1389. [PMID: 36059156 PMCID: PMC9828572 DOI: 10.1002/jmor.21504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 01/12/2023]
Abstract
Porosomes are plasma membrane structures in secretory cells that allow transient docking and/or partial fusion of vesicles during which they release their content then disengage. This is referred to as "kiss and run" exocytosis. During early pregnancy, at the time of receptivity, there is a high level of vesicle activity in uterine epithelial cells (UECs). One of the secretory pathways for these vesicles could be via porosomes, which have yet to be identified in UECs. This study identified porosomes in the apical plasma membrane of UECs for the first time. These structures were present on days 1, 5.5, and 6 of early pregnancy, where they likely facilitate partial secretion via "kiss and run" exocytosis. The porosomes were measured and quantified on days 1, 5.5, and 6, which showed there are significantly more porosomes on day 5.5 (receptive) compared to day 1 (nonreceptive) of pregnancy. This increase in porosome numbers may reflect major morphological and molecular changes in the apical plasma membrane at this time such as increased cholesterol and soluble NSF attachment protein receptor proteins, as these are structural and functional components of the porosome complex assembly. Porosomes were observed in both resting (inactive) and dilated (active) states on days 1, 5.5, and 6 of early pregnancy. Porosomes on day 5.5 are significantly more active than on day 1 as demonstrated by the dilation of their base diameter. Further two-way ANOVA analysis of base diameter in resting and dilated states found a significant increase in porosome activity in day 5.5 compared to day 1. This study therefore indicates an increase in the number and activity of porosomes at the time of uterine receptivity in the rat, revealing a mechanism by which the UECs modify the uterine luminal environment at this time.
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Affiliation(s)
- Sadaf N. Kalam
- School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Samson Dowland
- School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Laura Lindsay
- School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Christopher R. Murphy
- School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
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5
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Synaptic Secretion and Beyond: Targeting Synapse and Neurotransmitters to Treat Neurodegenerative Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:9176923. [PMID: 35923862 PMCID: PMC9343216 DOI: 10.1155/2022/9176923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/16/2022] [Accepted: 06/04/2022] [Indexed: 11/17/2022]
Abstract
The nervous system is important, because it regulates the physiological function of the body. Neurons are the most basic structural and functional unit of the nervous system. The synapse is an asymmetric structure that is important for neuronal function. The chemical transmission mode of the synapse is realized through neurotransmitters and electrical processes. Based on vesicle transport, the abnormal information transmission process in the synapse can lead to a series of neurorelated diseases. Numerous proteins and complexes that regulate the process of vesicle transport, such as SNARE proteins, Munc18-1, and Synaptotagmin-1, have been identified. Their regulation of synaptic vesicle secretion is complicated and delicate, and their defects can lead to a series of neurodegenerative diseases. This review will discuss the structure and functions of vesicle-based synapses and their roles in neurons. Furthermore, we will analyze neurotransmitter and synaptic functions in neurodegenerative diseases and discuss the potential of using related drugs in their treatment.
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6
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Chang CW, Hsiao YT, Scheuer KS, Jackson MB. Full-Fusion and Kiss-and-Run in Chromaffin Cells controlled by Irreversible Vesicle Size-Dependent Fusion Pore Transitions. Cell Calcium 2022; 105:102606. [DOI: 10.1016/j.ceca.2022.102606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 05/18/2022] [Indexed: 11/02/2022]
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Petrov AM, Zakirjanova GF, Kovyazina IV, Tsentsevitsky AN, Bukharaeva EA. Adrenergic receptors control frequency-dependent switching of the exocytosis mode between "full-collapse" and "kiss-and-run" in murine motor nerve terminal. Life Sci 2022; 296:120433. [PMID: 35219696 DOI: 10.1016/j.lfs.2022.120433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 12/22/2022]
Abstract
AIMS Neurotransmitter release from the synaptic vesicles can occur through two modes of exocytosis: "full-collapse" or "kiss-and-run". Here we investigated how increasing the nerve activity and pharmacological stimulation of adrenoceptors can influence the mode of exocytosis in the motor nerve terminal. METHODS Recording of endplate potentials with intracellular microelectrodes was used to estimate acetylcholine release. A fluorescent dye FM1-43 and its quenching with sulforhodamine 101 were utilized to visualize synaptic vesicle recycling. KEY FINDINGS An increase in the frequency of stimulation led to a decrease in the rate of FM1-43 unloading despite the higher number of quanta released. High frequency activity promoted neurotransmitter release via the kiss-and-run mechanism. This was confirmed by experiments utilizing (I) FM1-43 dye quencher, that is able to pass into the synaptic vesicle via fusion pore, and (II) loading of FM1-43 by compensatory endocytosis. Noradrenaline and specific α2-adrenoreceptors agonist, dexmedetomidine, controlled the mode of synaptic vesicle recycling at high frequency activity. Their applications favored neurotransmitter release via full-collapse exocytosis rather than the kiss-and-run pathway. SIGNIFICANCE At the diaphragm neuromuscular junctions, neuronal commands are translated into contractions necessary for respiration. During stress, an increase in discharge rate of the phrenic nerve shifts the exocytosis from the full-collapse to the kiss-and-run mode. The stress-related molecule, noradrenaline, restricts neurotransmitter release in response to a high frequency activity, and prevents the shift in the mode of exocytosis through α2-adrenoceptor activation. This may be a component of the mechanism that limits overstimulation of the respiratory system during stress.
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Affiliation(s)
- Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia; Kazan State Medical University, Kazan, Russia.
| | - Guzalia F Zakirjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
| | - Irina V Kovyazina
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia; Kazan State Medical University, Kazan, Russia
| | - Andrei N Tsentsevitsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
| | - Ellya A Bukharaeva
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
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8
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Nguyen TD, Mellander L, Lork A, Thomen A, Philipsen M, Kurczy ME, Phan NT, Ewing AG. Visualization of Partial Exocytotic Content Release and Chemical Transport into Nanovesicles in Cells. ACS NANO 2022; 16:4831-4842. [PMID: 35189057 PMCID: PMC8945366 DOI: 10.1021/acsnano.2c00344] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
For decades, "all-or-none" and "kiss-and-run" were thought to be the only major exocytotic release modes in cell-to-cell communication, while the significance of partial release has not yet been widely recognized and accepted owing to the lack of direct evidence for exocytotic partial release. Correlative imaging with transmission electron microscopy and NanoSIMS imaging and a dual stable isotope labeling approach was used to study the cargo status of vesicles before and after exocytosis; demonstrating a measurable loss of transmitter in individual vesicles following stimulation due to partial release. Model secretory cells were incubated with 13C-labeled l-3,4-dihydroxyphenylalanine, resulting in the loading of 13C-labeled dopamine into their vesicles. A second label, di-N-desethylamiodarone, having the stable isotope 127I, was introduced during stimulation. A significant drop in the level of 13C-labeled dopamine and a reduction in vesicle size, with an increasing level of 127I-, was observed in vesicles of stimulated cells. Colocalization of 13C and 127I- in several vesicles was observed after stimulation. Thus, chemical visualization shows transient opening of vesicles to the exterior of the cell without full release the dopamine cargo. We present a direct calculation for the fraction of neurotransmitter release from combined imaging data. The average vesicular release is 60% of the total catecholamine. An important observation is that extracellular molecules can be introduced to cells during the partial exocytotic release process. This nonendocytic transport process appears to be a general route of entry that might be exploited pharmacologically.
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Affiliation(s)
- Tho Duc
Khanh Nguyen
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Lisa Mellander
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Alicia Lork
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Aurélien Thomen
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Mai Philipsen
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Gothenburg SE-412 96, Sweden
| | - Michael E. Kurczy
- DMPK,
Research and Early Development, Cardiovascular, Renal and Metabolism
(CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg S-431 83, Sweden
| | - Nhu T.N. Phan
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
| | - Andrew G. Ewing
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Gothenburg SE-412 96, Sweden
- E-mail:
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9
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Inhibiting endocytosis in CGRP + nociceptors attenuates inflammatory pain-like behavior. Nat Commun 2021; 12:5812. [PMID: 34608164 PMCID: PMC8490418 DOI: 10.1038/s41467-021-26100-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 09/06/2021] [Indexed: 12/20/2022] Open
Abstract
The advantage of locally applied anesthetics is that they are not associated with the many adverse effects, including addiction liability, of systemically administered analgesics. This therapeutic approach has two inherent pitfalls: specificity and a short duration of action. Here, we identified nociceptor endocytosis as a promising target for local, specific, and long-lasting treatment of inflammatory pain. We observed preferential expression of AP2α2, an α-subunit isoform of the AP2 complex, within CGRP+/IB4- nociceptors in rodents and in CGRP+ dorsal root ganglion neurons from a human donor. We utilized genetic and pharmacological approaches to inhibit nociceptor endocytosis demonstrating its role in the development and maintenance of acute and chronic inflammatory pain. One-time injection of an AP2 inhibitor peptide significantly reduced acute and chronic pain-like behaviors and provided prolonged analgesia. We evidenced sexually dimorphic recovery responses to this pharmacological approach highlighting the importance of sex differences in pain development and response to analgesics. The authors show the endocytotic adaptor subunit called AP2A2 is differentially expressed in CGRP+ nociceptors. Locally inhibiting nociceptor endocytosis with a lipidated AP2 inhibitor peptide reduces acute and chronic pain-like behaviour in mice and rats, indicating prolonged analgesia.
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10
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Kamalesh K, Scher N, Biton T, Schejter ED, Shilo BZ, Avinoam O. Exocytosis by vesicle crumpling maintains apical membrane homeostasis during exocrine secretion. Dev Cell 2021; 56:1603-1616.e6. [PMID: 34102104 PMCID: PMC8191493 DOI: 10.1016/j.devcel.2021.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/17/2021] [Accepted: 05/06/2021] [Indexed: 12/14/2022]
Abstract
Exocrine secretion commonly employs micron-scale vesicles that fuse to a limited apical surface, presenting an extreme challenge for maintaining membrane homeostasis. Using Drosophila melanogaster larval salivary glands, we show that the membranes of fused vesicles undergo actomyosin-mediated folding and retention, which prevents them from incorporating into the apical surface. In addition, the diffusion of proteins and lipids between the fused vesicle and the apical surface is limited. Actomyosin contraction and membrane crumpling are essential for recruiting clathrin-mediated endocytosis to clear the retained vesicular membrane. Finally, we also observe membrane crumpling in secretory vesicles of the mouse exocrine pancreas. We conclude that membrane sequestration by crumpling followed by targeted endocytosis of the vesicular membrane, represents a general mechanism of exocytosis that maintains membrane homeostasis in exocrine tissues that employ large secretory vesicles.
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Affiliation(s)
- Kumari Kamalesh
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel; Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Nadav Scher
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tom Biton
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel; Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal D Schejter
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ben-Zion Shilo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
| | - Ori Avinoam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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Release Mode Dynamically Regulates the RRP Refilling Mechanism at Individual Hippocampal Synapses. J Neurosci 2020; 40:8426-8437. [PMID: 32989096 DOI: 10.1523/jneurosci.3029-19.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Synaptic strength and reliability are determined by the number of vesicles released per action potential and the availability of release-competent vesicles in the readily releasable pool (RRP). Compared with release of a single vesicle (univesicular release), multivesicular release (MVR) would speed up RRP depletion, yet whether the RRP is refilled differently during the two different release modes has not been investigated. Here, we address this question by quantitative optical imaging with an axon-targeting glutamate sensor, iGluSnFRpre. We found that hippocampal synapses preferentially release multiple vesicles per action potential at high extracellular calcium or by paired-pulse stimulation. When MVR prevails, the RRP is recovered very rapidly with a time constant of 430 ms. This rapid recovery is mediated by dynamin-dependent endocytosis followed by direct reuse of retrieved vesicles. Furthermore, our simulation proved that the portion of retrieved vesicles that directly refill the RRP increases dramatically (>70%) in MVR compared with that in univesicular release (<10%). These results suggest that the contribution of rapid and direct recruitment of retrieved vesicle to the RRP changes dynamically with release mode at the level of individual synapses, which suggests a form of presynaptic homeostatic plasticity for reliable synaptic transmission during various synaptic activity.SIGNIFICANCE STATEMENT The number of vesicles released in response to an action potential and the number of release competent vesicles in the readily releasable pool (RRP) are the fundamental determinants of synaptic efficacy. Despite its functional advantages, releasing multiple vesicles, especially at small synapses, can deplete the RRP after a couple of action potentials. To prevent failure of synaptic transmission, the RRP should be refilled rapidly, yet whether the RRP replenishment process is regulated by the release mode has not been investigated. Here, using quantitative optical glutamate imaging and simulation, we demonstrate that the contribution of the fast refilling mechanism changes with release mode at the level of individual synapses, suggesting a rapid form of presynaptic homeostatic plasticity during various synaptic activity.
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12
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Phosphatidylinositol-4,5-Biphosphate (PI(4,5)P 2) Is Required for Rapid Endocytosis in Chromaffin Cells. BIOMED RESEARCH INTERNATIONAL 2020; 2020:9692503. [PMID: 32964048 PMCID: PMC7501565 DOI: 10.1155/2020/9692503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/17/2020] [Indexed: 12/27/2022]
Abstract
Objective Phosphoinositides play a regulatory role in clathrin-mediated endocytosis. However, their involvement in clathrin-independent endocytosis termed rapid endocytosis (RE), which is the mode of vesicle recycling during neurotransmitter release by transient fusion (known as kiss-and-run), has not been investigated. Here, we used patch-clamp recording of whole-cell membrane capacitance in adrenal chromaffin cells (ACC) to monitor changes of RE kinetics in response to pharmacological alteration of phosphatidylinositol-4,5-biphosphate (PI(4,5)P2) level by phenylarsine oxide (PAO) or antibody against phosphatidylinositol 4-kinase (AbPI4K). Results We found that PAO and AbPI4K significantly abrogated RE kinetics. Infusion of PI(4,5)P2 through the patch pipette potentiated RE kinetics and reversed PAO- and AbPI4K-induced blockade of RE. Similarly, the application of the bifunctional thiol dithiothreitol (DTT) to PAO-treated cells completely prevented the inhibitory effect of PAO on RE. These findings indicate that PI(4,5)P2 is implicated in the signaling (mechanistic) process of RE in ACC.
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13
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Vardjan N, Parpura V, Verkhratsky A, Zorec R. Gliocrine System: Astroglia as Secretory Cells of the CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:93-115. [PMID: 31583585 DOI: 10.1007/978-981-13-9913-8_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the extracellular space, around the nearby synapses and also those released at much farther locations in the CNS, by their cell surface receptors, get excited to then release their own signaling molecules. This contributes to the brain information processing, based on diffusion within the extracellular space around the synapses and on convection when locales relatively far away from the release sites are involved. These functions resemble secretion from endocrine cells, therefore astrocytes were termed to be a part of the gliocrine system in 2015. An important mechanism, by which astrocytes release signaling molecules is the merger of the vesicle membrane with the plasmalemma, i.e., exocytosis. Signaling molecules stored in astroglial secretory vesicles can be discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This leads to a fusion pore formation, a channel that must widen to allow the exit of the Vesiclal cargo. Upon complete vesicle membrane fusion, this process also integrates other proteins, such as receptors, transporters and channels into the plasma membrane, determining astroglial surface signaling landscape. Vesiclal cargo, together with the whole vesicle can also exit astrocytes by the fusion of multivesicular bodies with the plasma membrane (exosomes) or by budding of vesicles (ectosomes) from the plasma membrane into the extracellular space. These astroglia-derived extracellular vesicles can later interact with various target cells. Here, the characteristics of four types of astroglial secretory vesicles: synaptic-like microvesicles, dense-core vesicles, secretory lysosomes, and extracellular vesicles, are discussed. Then machinery for vesicle-based exocytosis, second messenger regulation and the kinetics of exocytotic vesicle content discharge or release of extracellular vesicles are considered. In comparison to rapidly responsive, electrically excitable neurons, the receptor-mediated cytosolic excitability-mediated astroglial exocytotic vesicle-based transmitter release is a relatively slow process.
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Affiliation(s)
- Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
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14
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Qin X, Tsien RW, Park H. Real-time three-dimensional tracking of single synaptic vesicles reveals that synaptic vesicles undergoing kiss-and-run fusion remain close to their original fusion site before reuse. Biochem Biophys Res Commun 2019; 514:1004-1008. [PMID: 31092326 DOI: 10.1016/j.bbrc.2019.05.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 05/04/2019] [Indexed: 01/10/2023]
Abstract
The release of neurotransmitters via the fusion between synaptic vesicles and the presynaptic membrane is an essential step in synaptic transmission. Synaptic vesicles generally undergo two distinct modes of exocytosis called full-collapse fusion and kiss-and-run fusion. In kiss-and-run fusion, the fusion pore of the synaptic vesicle opens transiently without the vesicle collapsing fully into the plasma membrane; thus, each synaptic vesicle can be used multiple times to release neurotransmitters. Despite considerable research, the detailed mechanisms that underlie kiss-and-run fusion remain elusive, particularly the location of synaptic vesicles after kiss-and-run events. To address this question, we performed real-time three-dimensional tracking of single synaptic vesicles labeled with a single quantum dot in the presynaptic terminal of cultured hippocampal neurons and analyzed the three-dimensional trajectories of these vesicles undergoing kiss-and-run fusion. We found that the majority of these synaptic vesicles underwent another exocytosis event within 120 nm of their original fusion site and underwent a second exocytosis event within 10 s of the first fusion event. These results indicate that after kiss-and-run fusion, synaptic vesicles remain relatively close to their original fusion site and can release repeatedly at brief intervals, allowing neurons to maintain neurotransmitter release during bursting activity.
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Affiliation(s)
- Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Richard W Tsien
- NYU Neuroscience Institute and Department of Physiology and Neuroscience, New York University, New York, NY, 10016, USA
| | - Hyokeun Park
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
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15
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Tse A, Lee AK, Takahashi N, Gong A, Kasai H, Tse FW. Strong stimulation triggers full fusion exocytosis and very slow endocytosis of the small dense core granules in carotid glomus cells. J Neurogenet 2018; 32:267-278. [PMID: 30484390 DOI: 10.1080/01677063.2018.1497629] [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: 10/27/2022]
Abstract
Chemosensory glomus cells of the carotid bodies release transmitters, including ATP and dopamine mainly via the exocytosis of small dense core granules (SDCGs, vesicular diameter of ∼100 nm). Using carbon-fiber amperometry, we showed previously that with a modest uniform elevation in cytosolic Ca2+ concentration ([Ca2+]i of ∼0.5 µM), SDCGs of rat glomus cells predominantly underwent a "kiss-and-run" mode of exocytosis. Here, we examined whether a larger [Ca2+]i rise influenced the mode of exocytosis. Activation of voltage-gated Ca2+ channels by a train of voltage-clamped depolarizations which elevated [Ca2+]i to ∼1.6 μM increased the cell membrane capacitance by ∼2.5%. At 30 s after such a stimulus, only 5% of the added membrane was retrieved. Flash photolysis of caged-Ca2+ (which elevated [Ca2+]i to ∼16 μM) increased cell membrane capacitance by ∼13%, and only ∼30% of the added membrane was retrieved at 30 s after the UV flash. When exocytosis and endocytosis were monitored using the two-photon excitation and extracellular polar tracer (TEP) imaging of FM1-43 fluorescence in conjunction with photolysis of caged Ca2+, almost uniform exocytosis was detected over the cell's entire surface and it was followed by slow endocytosis. Immunocytochemistry showed that the cytoplasmic densities of dynamin I, II and clathrin (key proteins that mediate endocytosis) in glomus cells were less than half of those in adrenal chromaffin cells, suggesting that a lower expression of endocytotic machinery may underlie the slow endocytosis in glomus cells. An analysis of the relative change in the signals from two fluorescent dyes that simultaneously monitored the addition of vesicular volume and plasma membrane surface area, suggested that with an intense stimulus, SDCGs of glomus cells underwent full fusion without any significant "compound" exocytosis. Therefore, during a severe hypoxic challenge, glomus granules undergo full fusion for a more complete release of transmitters.
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Affiliation(s)
- Amy Tse
- a Department of Pharmacology and Neuroscience and Metal Health Institute , University of Alberta , Edmonton , Canada
| | - Andy K Lee
- a Department of Pharmacology and Neuroscience and Metal Health Institute , University of Alberta , Edmonton , Canada
| | - Noriko Takahashi
- b Department of Physiology , Kitasato University School of Medicine , Sagamihara , Japan
| | - Alex Gong
- a Department of Pharmacology and Neuroscience and Metal Health Institute , University of Alberta , Edmonton , Canada
| | - Haruo Kasai
- c Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine , The University of Tokyo , Bunkyo-ku , Japan.,d International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo , Bunkyo-ku , Japan
| | - Frederick W Tse
- a Department of Pharmacology and Neuroscience and Metal Health Institute , University of Alberta , Edmonton , Canada
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16
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Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804743] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yong Woong Jun
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
- Center for Converging Humanities; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Donghee Ma
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
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17
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Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018; 57:10142-10147. [PMID: 29873167 DOI: 10.1002/anie.201804743] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Indexed: 11/10/2022]
Abstract
Vesicles exchange their contents through membrane fusion processes, kiss-and-run and full-collapse fusion. Indirect observation of these fusion processes using artificial vesicles enhanced our understanding on the molecular mechanisms involved. Direct observation of the fusion processes in a real biological system, however, remains a challenge owing to many technical obstacles. We report a ratiometric two-photon probe offering real-time tracking of lysosomal ATP with quantitative information for the first time. By applying the probe to two-photon live-cell imaging, the lysosomal membrane fusion process in cells has been directly observed and the concentration of its content, lysosomal ATP, has been measured. Results show that the kiss-and-run process between lysosomes proceeds through repeated transient interactions with gradual content mixing, whereas the full-fusion process occurs at once. Furthermore, it is confirmed that both the fusion processes proceed with conservation of the content. Such a small-molecule probe exerts minimal disturbance and hence has potential for studying various biological processes associated with lysosomal ATP.
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Affiliation(s)
- Yong Woong Jun
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea.,Center for Converging Humanities, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Donghee Ma
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
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18
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Ghosh D, Nieves-Cintrón M, Tajada S, Brust-Mascher I, Horne MC, Hell JW, Dixon RE, Santana LF, Navedo MF. Dynamic L-type Ca V1.2 channel trafficking facilitates Ca V1.2 clustering and cooperative gating. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1341-1355. [PMID: 29959960 PMCID: PMC6407617 DOI: 10.1016/j.bbamcr.2018.06.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 11/21/2022]
Abstract
L-type CaV1.2 channels are key regulators of gene expression, cell excitability and muscle contraction. CaV1.2 channels organize in clusters throughout the plasma membrane. This channel organization has been suggested to contribute to the concerted activation of adjacent CaV1.2 channels (e.g. cooperative gating). Here, we tested the hypothesis that dynamic intracellular and perimembrane trafficking of CaV1.2 channels is critical for formation and dissolution of functional channel clusters mediating cooperative gating. We found that CaV1.2 moves in vesicular structures of circular and tubular shape with diverse intracellular and submembrane trafficking patterns. Both microtubules and actin filaments are required for dynamic movement of CaV1.2 vesicles. These vesicles undergo constitutive homotypic fusion and fission events that sustain CaV1.2 clustering, channel activity and cooperative gating. Our study suggests that CaV1.2 clusters and activity can be modulated by diverse and unique intracellular and perimembrane vesicular dynamics to fine-tune Ca2+ signals.
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Affiliation(s)
- Debapriya Ghosh
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Madeline Nieves-Cintrón
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Sendoa Tajada
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Ingrid Brust-Mascher
- Advanced Imaging Facility, School of Veterinary Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Mary C Horne
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Johannes W Hell
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Rose E Dixon
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Luis F Santana
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Manuel F Navedo
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA.
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19
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Klein O, Roded A, Hirschberg K, Fukuda M, Galli SJ, Sagi-Eisenberg R. Imaging FITC-dextran as a Reporter for Regulated Exocytosis. J Vis Exp 2018. [PMID: 29985342 DOI: 10.3791/57936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Regulated exocytosis is a process by which cargo, which is stored in secretory granules (SGs), is released in response to a secretory trigger. Regulated exocytosis is fundamental for intercellular communication and is a key mechanism for the secretion of neurotransmitters, hormones, inflammatory mediators, and other compounds, by a variety of cells. At least three distinct mechanisms are known for regulated exocytosis: full exocytosis, where a single SG fully fuses with the plasma membrane, kiss-and-run exocytosis, where a single SG transiently fuses with the plasma membrane, and compound exocytosis, where several SGs fuse with each other, prior to or after SG fusion with the plasma membrane. The type of regulated exocytosis undertaken by a cell is often dictated by the type of secretory trigger. However, in many cells, a single secretory trigger can activate multiple modes of regulated exocytosis simultaneously. Despite their abundance and importance across cell types and species, the mechanisms that determine the different modes of secretion are largely unresolved. One of the main challenges in investigating the different modes of regulated exocytosis, is the difficulty in distinguishing between them as well as exploring them separately. Here we describe the use of fluorescein isothiocyanate (FITC)-dextran as an exocytosis reporter, and live cell imaging, to differentiate between the different pathways of regulated exocytosis, focusing on compound exocytosis, based on the robustness and duration of the exocytic events.
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Affiliation(s)
- Ofir Klein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Amit Roded
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Koret Hirschberg
- Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University
| | - Stephen J Galli
- Departments of Pathology and of Microbiology and Immunology and Sean N. Parker Center for Allergy and Asthma Research, School of Medicine, Stanford University
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University;
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20
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Alford S, Hamm H, Rodriguez S, Zurawski Z. Gβγ SNARE Interactions and Their Behavioral Effects. Neurochem Res 2018; 44:636-649. [PMID: 29752624 DOI: 10.1007/s11064-018-2531-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/09/2018] [Accepted: 04/16/2018] [Indexed: 11/25/2022]
Abstract
Presynaptic terminals possess interlocking molecular mechanisms that control exocytosis. An example of such complexity is the modulation of release by presynaptic G Protein Coupled Receptors (GPCRs). GPCR ubiquity at synapses-GPCRs are present at every studied presynaptic terminal-underlies their critical importance in synaptic function. GPCRs mediate presynaptic modulation by mechanisms including via classical Gα effectors, but membrane-delimited actions of Gβγ can also alter probability of release by altering presynaptic ionic conductances. This directly or indirectly modifies action potential-evoked presynaptic Ca2+ entry. In addition, Gβγ can interact directly with SNARE complexes responsible for synaptic vesicle fusion to reduce peak cleft neurotransmitter concentrations during evoked release. The interaction of Gβγ with SNARE is displaced via competitive interaction with C2AB-domain containing calcium sensors such as synaptotagmin I in a Ca2+-sensitive manner, restoring exocytosis. Synaptic modulation of this form allows selective inhibition of postsynaptic receptor-mediated responses, and this, in combination with Ca2+ sensitivity of Gβγ effects on SNARE complexes allows for specific behavioral outcomes. One such outcome mediated by 5-HT receptors in the spinal cord seen in all vertebrates shows remarkable synergy between presynaptic effects of Gβγ and postsynaptic 5-HT-mediated changes in activation of Ca2+-dependent K+ channels. While acting through entirely separate cellular compartments and signal transduction pathways, these effects converge on the same effect on locomotion and other critical functions of the central nervous system.
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Affiliation(s)
- Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA.
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, 37232-6600, USA
| | - Shelagh Rodriguez
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA
| | - Zack Zurawski
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, 37232-6600, USA
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21
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Wu Z, Thiyagarajan S, O'Shaughnessy B, Karatekin E. Regulation of Exocytotic Fusion Pores by SNARE Protein Transmembrane Domains. Front Mol Neurosci 2017; 10:315. [PMID: 29066949 PMCID: PMC5641348 DOI: 10.3389/fnmol.2017.00315] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/19/2017] [Indexed: 12/26/2022] Open
Abstract
Calcium-triggered exocytotic release of neurotransmitters and hormones from neurons and neuroendocrine cells underlies neuronal communication, motor activity and endocrine functions. The core of the neuronal exocytotic machinery is composed of soluble N-ethyl maleimide sensitive factor attachment protein receptors (SNAREs). Formation of complexes between vesicle-attached v- and plasma-membrane anchored t-SNAREs in a highly regulated fashion brings the membranes into close apposition. Small, soluble proteins called Complexins (Cpx) and calcium-sensing Synaptotagmins cooperate to block fusion at low resting calcium concentrations, but trigger release upon calcium increase. A growing body of evidence suggests that the transmembrane domains (TMDs) of SNARE proteins play important roles in regulating the processes of fusion and release, but the mechanisms involved are only starting to be uncovered. Here we review recent evidence that SNARE TMDs exert influence by regulating the dynamics of the fusion pore, the initial aqueous connection between the vesicular lumen and the extracellular space. Even after the fusion pore is established, hormone release by neuroendocrine cells is tightly controlled, and the same may be true of neurotransmitter release by neurons. The dynamics of the fusion pore can regulate the kinetics of cargo release and the net amount released, and can determine the mode of vesicle recycling. Manipulations of SNARE TMDs were found to affect fusion pore properties profoundly, both during exocytosis and in biochemical reconstitutions. To explain these effects, TMD flexibility, and interactions among TMDs or between TMDs and lipids have been invoked. Exocytosis has provided the best setting in which to unravel the underlying mechanisms, being unique among membrane fusion reactions in that single fusion pores can be probed using high-resolution methods. An important role will likely be played by methods that can probe single fusion pores in a biochemically defined setting which have recently become available. Finally, computer simulations are valuable mechanistic tools because they have the power to access small length scales and very short times that are experimentally inaccessible.
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Affiliation(s)
- Zhenyong Wu
- Department of Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, CT, United States.,Nanobiology Institute, Yale University, West Haven, CT, United States
| | | | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY, United States
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, CT, United States.,Nanobiology Institute, Yale University, West Haven, CT, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States.,Laboratoire de Neurophotonique, Université Paris Descartes, Faculté des Sciences Fondamentales et Biomédicales, Centre National de la Recherche Scientifique (CNRS), Paris, France
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22
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Pontes B, Monzo P, Gauthier NC. Membrane tension: A challenging but universal physical parameter in cell biology. Semin Cell Dev Biol 2017; 71:30-41. [PMID: 28851599 DOI: 10.1016/j.semcdb.2017.08.030] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/08/2017] [Accepted: 08/13/2017] [Indexed: 01/03/2023]
Abstract
The plasma membrane separates the interior of cells from the outside environment. The membrane tension, defined as the force per unit length acting on a cross-section of membrane, regulates many vital biological processes. In this review, we summarize the first historical findings and the latest advances, showing membrane tension as an important physical parameter in cell biology. We also discuss how this parameter must be better integrated and we propose experimental approaches for key unanswered questions.
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Affiliation(s)
- Bruno Pontes
- LPO-COPEA, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Pascale Monzo
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Nils C Gauthier
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy.
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23
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Complexin Mutants Reveal Partial Segregation between Recycling Pathways That Drive Evoked and Spontaneous Neurotransmission. J Neurosci 2017; 37:383-396. [PMID: 28077717 DOI: 10.1523/jneurosci.1854-16.2016] [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: 06/09/2016] [Revised: 11/10/2016] [Accepted: 11/15/2016] [Indexed: 11/21/2022] Open
Abstract
Synaptic vesicles fuse at morphological specializations in the presynaptic terminal termed active zones (AZs). Vesicle fusion can occur spontaneously or in response to an action potential. Following fusion, vesicles are retrieved and recycled within nerve terminals. It is still unclear whether vesicles that fuse spontaneously or following evoked release share similar recycling mechanisms. Genetic deletion of the SNARE-binding protein complexin dramatically increases spontaneous fusion, with the protein serving as the synaptic vesicle fusion clamp at Drosophila synapses. We examined synaptic vesicle recycling pathways at complexin null neuromuscular junctions, where spontaneous release is dramatically enhanced. We combined loading of the lipophilic dye FM1-43 with photoconversion, electron microscopy, and electrophysiology to monitor evoked and spontaneous recycling vesicle pools. We found that the total number of recycling vesicles was equal to those retrieved through spontaneous and evoked pools, suggesting that retrieval following fusion is partially segregated for spontaneous and evoked release. In addition, the kinetics of FM1-43 destaining and synaptic depression measured in the presence of the vesicle-refilling blocker bafilomycin indicated that spontaneous and evoked recycling pools partially intermix during the release process. Finally, FM1-43 photoconversion combined with electron microscopy analysis indicated that spontaneous recycling preferentially involves synaptic vesicles in the vicinity of AZs, whereas vesicles recycled following evoked release involve a larger intraterminal pool. Together, these results suggest that spontaneous and evoked vesicles use separable recycling pathways and then partially intermix during subsequent rounds of fusion. SIGNIFICANCE STATEMENT Neurotransmitter release involves fusion of synaptic vesicles with the plasma membrane in response to an action potential, or spontaneously in the absence of stimulation. Upon fusion, vesicles are retrieved and recycled, and it is unclear whether recycling pathways for evoked and spontaneous vesicles are segregated after fusion. We addressed this question by taking advantage of preparations lacking the synaptic protein complexin, which have elevated spontaneous release that enables reliable tracking of the spontaneous recycling pool. Our results suggest that spontaneous and evoked recycling pathways are segregated during the retrieval process but can partially intermix during stimulation.
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24
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Lasič E, Stenovec M, Kreft M, Robinson PJ, Zorec R. Dynamin regulates the fusion pore of endo- and exocytotic vesicles as revealed by membrane capacitance measurements. Biochim Biophys Acta Gen Subj 2017; 1861:2293-2303. [PMID: 28669852 DOI: 10.1016/j.bbagen.2017.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/24/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND Dynamin is a multidomain GTPase exhibiting mechanochemical and catalytic properties involved in vesicle scission from the plasmalemma during endocytosis. New evidence indicates that dynamin is also involved in exocytotic release of catecholamines, suggesting the existence of a dynamin-regulated structure that couples endo- to exocytosis. METHODS Thus we here employed high-resolution cell-attached capacitance measurements and super-resolution structured illumination microscopy to directly examine single vesicle interactions with the plasmalemma in cultured rat astrocytes treated with distinct pharmacological modulators of dynamin activity. Fluorescent dextrans and the lipophilic plasmalemmal marker DiD were utilized to monitor uptake and distribution of vesicles in the peri-plasmalemmal space and in the cell cytosol. RESULTS Dynamin inhibition with Dynole™-34-2 and Dyngo™-4a prevented vesicle internalization into the cytosol and decreased fusion pore conductance of vesicles that remained attached to the plasmalemma via a narrow fusion pore that lapsed into a state of repetitive opening and closing - flickering. In contrast, the dynamin activator Ryngo™-1-23 promoted vesicle internalization and favored fusion pore closure by prolonging closed and shortening open fusion pore dwell times. Immunocytochemical staining revealed dextran uptake into dynamin-positive vesicles and increased dextran uptake into Syt4- and VAMP2-positive vesicles after dynamin inhibition, indicating prolonged retention of these vesicles at the plasmalemma. CONCLUSIONS Our results have provided direct evidence for a role of dynamin in regulation of fusion pore geometry and kinetics of endo- and exocytotic vesicles, indicating that both share a common dynamin-regulated structural intermediate, the fusion pore.
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Affiliation(s)
- Eva Lasič
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia.
| | - Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia; University of Ljubljana, Biotechnical Faculty, Department of Biology, CPAE, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Phillip J Robinson
- Children's Medical Research Institute, The University of Sydney, Australia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia.
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25
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Abstract
Exocytosis is an important cellular process controlled by metabolic signaling. It involves vesicle fusion to the plasma membrane, followed by the opening of a fusion pore, and the subsequent release of the vesicular lumen content into the extracellular space. While most modeling efforts focus on the events leading to membrane fusion, how the vesicular membrane remodels after fusing to plasma membrane remains unclear. This latter event dictates the nature and the efficiency of exocytotic vesicular secretions, and is thus critical for exocytotic function. We provide a generic membrane mechanical model to systematically study the fate of post-fusion vesicles. We show that while membrane stiffness favors full-collapse vesicle fusion into the plasma membrane, the intravesicular pressure swells the vesicle and causes the fusion pore to shrink. Dimensions of the vesicle and its associated fusion pore further modulate this mechanical antagonism. We systematically define the mechanical conditions that account for the full spectrum of the observed vesicular secretion modes. Our model therefore can serve as a unified theoretical framework that sheds light on the elaborate control mechanism of exocytosis.
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Affiliation(s)
- Thomas Stephens
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States of America. Equal contribution
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26
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Chang CW, Chiang CW, Jackson MB. Fusion pores and their control of neurotransmitter and hormone release. J Gen Physiol 2017; 149:301-322. [PMID: 28167663 PMCID: PMC5339513 DOI: 10.1085/jgp.201611724] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 01/06/2017] [Accepted: 01/19/2017] [Indexed: 11/20/2022] Open
Abstract
Chang et al. review fusion pore structure and dynamics and discuss the implications for hormone and neurotransmitter release Ca2+-triggered exocytosis functions broadly in the secretion of chemical signals, enabling neurons to release neurotransmitters and endocrine cells to release hormones. The biological demands on this process can vary enormously. Although synapses often release neurotransmitter in a small fraction of a millisecond, hormone release can be orders of magnitude slower. Vesicles usually contain multiple signaling molecules that can be released selectively and conditionally. Cells are able to control the speed, concentration profile, and content selectivity of release by tuning and tailoring exocytosis to meet different biological demands. Much of this regulation depends on the fusion pore—the aqueous pathway by which molecules leave a vesicle and move out into the surrounding extracellular space. Studies of fusion pores have illuminated how cells regulate secretion. Furthermore, the formation and growth of fusion pores serve as a readout for the progress of exocytosis, thus revealing key kinetic stages that provide clues about the underlying mechanisms. Herein, we review the structure, composition, and dynamics of fusion pores and discuss the implications for molecular mechanisms as well as for the cellular regulation of neurotransmitter and hormone release.
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Affiliation(s)
- Che-Wei Chang
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - Chung-Wei Chiang
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - Meyer B Jackson
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
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27
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Bost A, Shaib AH, Schwarz Y, Niemeyer BA, Becherer U. Large dense-core vesicle exocytosis from mouse dorsal root ganglion neurons is regulated by neuropeptide Y. Neuroscience 2017; 346:1-13. [PMID: 28089870 DOI: 10.1016/j.neuroscience.2017.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 12/12/2022]
Abstract
Peptidergic dorsal root ganglion (DRG) neurons transmit sensory and nociceptive information from the periphery to the central nervous system. Their synaptic activity is profoundly affected by neuromodulatory peptides stored and released from large dense-core vesicles (LDCVs). However, the mechanism of peptide secretion from DRG neurons is poorly understood. Using total internal reflection fluorescence microscopy (TIRFM), we visualized individual LDCVs loaded with fluorescent neuropeptide Y (NPY) and analyzed their stimulation-dependent release. We tested several protocols and found an overall low stimulation-secretion coupling that increased after raising intracellular Ca2+ concentration by applying a weak pre-stimulus. Interestingly, the stimulation protocol also influenced the mechanism of LDCV fusion. Depolarization of DRG neurons with a solution containing 60mM KCl triggered full fusion, kiss-and-run, and kiss-and-stay exocytosis with equal frequency. In contrast, field electrode stimulation primarily induced full fusion exocytosis. Finally, our results indicate that NPY can promote LDCV secretion. These results shed new light on the mechanism of NPY action during modulation of DRG neuron activity, an important pathway in the treatment of chronic pain.
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Affiliation(s)
- Anneka Bost
- Institute of Physiology, CIPMM, Saarland University, 66421 Homburg/Saar, Germany
| | - Ali H Shaib
- Institute of Physiology, CIPMM, Saarland University, 66421 Homburg/Saar, Germany
| | - Yvonne Schwarz
- Institute of Physiology, CIPMM, Saarland University, 66421 Homburg/Saar, Germany
| | - Barbara A Niemeyer
- Molecular Biophysics, CIPMM, Saarland University, 66421 Homburg/Saar, Germany
| | - Ute Becherer
- Institute of Physiology, CIPMM, Saarland University, 66421 Homburg/Saar, Germany.
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28
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Oleinick A, Svir I, Amatore C. 'Full fusion' is not ineluctable during vesicular exocytosis of neurotransmitters by endocrine cells. Proc Math Phys Eng Sci 2017; 473:20160684. [PMID: 28265193 PMCID: PMC5312129 DOI: 10.1098/rspa.2016.0684] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/17/2016] [Indexed: 11/12/2022] Open
Abstract
Vesicular exocytosis is an essential and ubiquitous process in neurons and endocrine cells by which neurotransmitters are released in synaptic clefts or extracellular fluids. It involves the fusion of a vesicle loaded with chemical messengers with the cell membrane through a nanometric fusion pore. In endocrine cells, unless it closes after some flickering ('Kiss-and-Run' events), this initial pore is supposed to expand exponentially, leading to a full integration of the vesicle membrane into the cell membrane-a stage called 'full fusion'. We report here a compact analytical formulation that allows precise measurements of the fusion pore expansion extent and rate to be extracted from individual amperometric spike time courses. These data definitively establish that, during release of catecholamines, fusion pores enlarge at most to approximately one-fifth of the radius of their parent vesicle, hence ruling out the ineluctability of 'full fusion'.
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Affiliation(s)
| | | | - Christian Amatore
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
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29
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Calcium transport into the cells of the sea urchin larva in relation to spicule formation. Proc Natl Acad Sci U S A 2016; 113:12637-12642. [PMID: 27791140 DOI: 10.1073/pnas.1612017113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigated the manner in which the sea urchin larva takes up calcium from its body cavity into the primary mesenchymal cells (PMCs) that are responsible for spicule formation. We used the membrane-impermeable fluorescent dye calcein and alexa-dextran, with or without a calcium channel inhibitor, and imaged the larvae in vivo with selective-plane illumination microscopy. Both fluorescent molecules are taken up from the body cavity into the PMCs and ectoderm cells, where the two labels are predominantly colocalized in particles, whereas the calcium-binding calcein label is mainly excluded from the endoderm and is concentrated in the spicules. The presence of vesicles and vacuoles inside the PMCs that have openings through the plasma membrane directly to the body cavity was documented using high-resolution cryo-focused ion beam-SEM serial imaging. Some of the vesicles and vacuoles are interconnected to form large networks. We suggest that these vacuolar networks are involved in direct sea water uptake. We conclude that the calcium pathway from the body cavity into cells involves nonspecific endocytosis of sea water with its calcium.
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30
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Battaglia-Mayer A, Babicola L, Satta E. Parieto-frontal gradients and domains underlying eye and hand operations in the action space. Neuroscience 2016; 334:76-92. [DOI: 10.1016/j.neuroscience.2016.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 07/06/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022]
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31
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Najafinobar N, Mellander LJ, Kurczy ME, Dunevall J, Angerer TB, Fletcher JS, Cans AS. Cholesterol Alters the Dynamics of Release in Protein Independent Cell Models for Exocytosis. Sci Rep 2016; 6:33702. [PMID: 27650365 PMCID: PMC5030643 DOI: 10.1038/srep33702] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/01/2016] [Indexed: 11/25/2022] Open
Abstract
Neurons communicate via an essential process called exocytosis. Cholesterol, an abundant lipid in both secretory vesicles and cell plasma membrane can affect this process. In this study, amperometric recordings of vesicular dopamine release from two different artificial cell models created from a giant unilamellar liposome and a bleb cell plasma membrane, show that with higher membrane cholesterol the kinetics for vesicular release are decelerated in a concentration dependent manner. This reduction in exocytotic speed was consistent for two observed modes of exocytosis, full and partial release. Partial release events, which only occurred in the bleb cell model due to the higher tension in the system, exhibited amperometric spikes with three distinct shapes. In addition to the classic transient, some spikes displayed a current ramp or plateau following the maximum peak current. These post spike features represent neurotransmitter release from a dilated pore before constriction and show that enhancing membrane rigidity via cholesterol adds resistance to a dilated pore to re-close. This implies that the cholesterol dependent biophysical properties of the membrane directly affect the exocytosis kinetics and that membrane tension along with membrane rigidity can influence the fusion pore dynamics and stabilization which is central to regulation of neurochemical release.
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Affiliation(s)
- Neda Najafinobar
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Lisa J. Mellander
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Michael E. Kurczy
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Johan Dunevall
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Tina B. Angerer
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - John S. Fletcher
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Ann-Sofie Cans
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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32
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Chang HF, Bzeih H, Schirra C, Chitirala P, Halimani M, Cordat E, Krause E, Rettig J, Pattu V. Endocytosis of Cytotoxic Granules Is Essential for Multiple Killing of Target Cells by T Lymphocytes. THE JOURNAL OF IMMUNOLOGY 2016; 197:2473-84. [PMID: 27527597 DOI: 10.4049/jimmunol.1600828] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/20/2016] [Indexed: 11/19/2022]
Abstract
CTLs are serial killers that kill multiple target cells via exocytosis of cytotoxic granules (CGs). CG exocytosis is tightly regulated and has been investigated in great detail; however, whether CG proteins are endocytosed following exocytosis and contribute to serial killing remains unknown. By using primary CTLs derived from a knock-in mouse of the CG membrane protein Synaptobrevin2, we show that CGs are endocytosed in a clathrin- and dynamin-dependent manner. Following acidification, endocytosed CGs are recycled through early and late, but not recycling endosomes. CGs are refilled with granzyme B at the late endosome stage and polarize to subsequent synapses formed between the CTL and new target cells. Importantly, inhibiting CG endocytosis in CTLs results in a significant reduction of their cytotoxic activity. Thus, our data demonstrate that continuous endocytosis of CG membrane proteins is a prerequisite for efficient serial killing of CTLs and identify key events in this process.
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Affiliation(s)
- Hsin-Fang Chang
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Hawraa Bzeih
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Claudia Schirra
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Praneeth Chitirala
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Mahantappa Halimani
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Emmanuelle Cordat
- Department of Physiology, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - Elmar Krause
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Jens Rettig
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Varsha Pattu
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
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33
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Moya-Díaz J, Álvarez YD, Montenegro M, Bayonés L, Belingheri AV, González-Jamett AM, Cárdenas AM, Marengo FD. Sustained Exocytosis after Action Potential-Like Stimulation at Low Frequencies in Mouse Chromaffin Cells Depends on a Dynamin-Dependent Fast Endocytotic Process. Front Cell Neurosci 2016; 10:184. [PMID: 27507935 PMCID: PMC4960491 DOI: 10.3389/fncel.2016.00184] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/08/2016] [Indexed: 12/17/2022] Open
Abstract
Under basal conditions the action potential firing rate of adrenal chromaffin cells is lower than 0.5 Hz. The maintenance of the secretory response at such frequencies requires a continuous replenishment of releasable vesicles. However, the mechanism that allows such vesicle replenishment remains unclear. Here, using membrane capacitance measurements on mouse chromaffin cells, we studied the mechanism of replenishment of a group of vesicles released by a single action potential-like stimulus (APls). The exocytosis triggered by APls (ETAP) represents a fraction (40%) of the immediately releasable pool, a group of vesicles highly coupled to voltage dependent calcium channels. ETAP was replenished with a time constant of 0.73 ± 0.11 s, fast enough to maintain synchronous exocytosis at 0.2–0.5 Hz stimulation. Regarding the mechanism involved in rapid ETAP replenishment, we found that it depends on the ready releasable pool; indeed depletion of this vesicle pool significantly delays ETAP replenishment. On the other hand, ETAP replenishment also correlates with a dynamin-dependent fast endocytosis process (τ = 0.53 ± 0.01 s). In this regard, disruption of dynamin function markedly inhibits the fast endocytosis and delays ETAP replenishment, but also significantly decreases the synchronous exocytosis during repetitive APls stimulation at low frequencies (0.2 and 0.5 Hz). Considering these findings, we propose a model in where both the transfer of vesicles from ready releasable pool and fast endocytosis allow rapid ETAP replenishment during low stimulation frequencies.
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Affiliation(s)
- José Moya-Díaz
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Yanina D Álvarez
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Mauricio Montenegro
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Lucas Bayonés
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Ana V Belingheri
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso Valparaíso, Chile
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso Valparaíso, Chile
| | - Fernando D Marengo
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
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34
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Axon diameter relates to synaptic bouton size: structural properties define computationally different types of cortical connections in primates. Brain Struct Funct 2016; 222:1169-1177. [DOI: 10.1007/s00429-016-1266-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 06/28/2016] [Indexed: 10/21/2022]
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35
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Zhao Y, Fang Q, Straub SG, Lindau M, Sharp GWG. Prostaglandin E1 inhibits endocytosis in the β-cell endocytosis. J Endocrinol 2016; 229:287-94. [PMID: 27068696 DOI: 10.1530/joe-15-0435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/11/2016] [Indexed: 12/23/2022]
Abstract
Prostaglandins inhibit insulin secretion in a manner similar to that of norepinephrine (NE) and somatostatin. As NE inhibits endocytosis as well as exocytosis, we have now examined the modulation of endocytosis by prostaglandin E1 (PGE1). Endocytosis following exocytosis was recorded by whole-cell patch clamp capacitance measurements in INS-832/13 cells. Prolonged depolarizing pulses producing a high level of Ca(2+) influx were used to stimulate maximal exocytosis and to deplete the readily releasable pool (RRP) of granules. This high Ca(2+) influx eliminates the inhibitory effect of PGE1 on exocytosis and allows specific characterization of the inhibitory effect of PGE1 on the subsequent compensatory endocytosis. After stimulating exocytosis, endocytosis was apparent under control conditions but was inhibited by PGE1 in a Pertussis toxin-sensitive (PTX)-insensitive manner. Dialyzing a synthetic peptide mimicking the C-terminus of the α-subunit of the heterotrimeric G-protein Gz into the cells blocked the inhibition of endocytosis by PGE1, whereas a control-randomized peptide was without effect. These results demonstrate that PGE1 inhibits endocytosis and Gz mediates the inhibition.
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Affiliation(s)
- Ying Zhao
- Department of Molecular MedicineCornell University, Ithaca, New York, USA School of Applied and Engineering PhysicsCornell University, Ithaca, New York, USA Laboratory for Nanoscale Cell BiologyMax-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
| | - Qinghua Fang
- School of Applied and Engineering PhysicsCornell University, Ithaca, New York, USA Laboratory for Nanoscale Cell BiologyMax-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
| | - Susanne G Straub
- Department of Molecular MedicineCornell University, Ithaca, New York, USA
| | - Manfred Lindau
- School of Applied and Engineering PhysicsCornell University, Ithaca, New York, USA Laboratory for Nanoscale Cell BiologyMax-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
| | - Geoffrey W G Sharp
- Department of Molecular MedicineCornell University, Ithaca, New York, USA
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36
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Kreft M, Jorgačevski J, Vardjan N, Zorec R. Unproductive exocytosis. J Neurochem 2016; 137:880-9. [DOI: 10.1111/jnc.13561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 01/21/2016] [Accepted: 01/25/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
- Celica BIOMEDICAL; Ljubljana Slovenia
- Department of Biology; Biotechnical Faculty; University of Ljubljana; Ljubljana Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology-Molecular Cell Physiology; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
- Celica BIOMEDICAL; Ljubljana Slovenia
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
- Celica BIOMEDICAL; Ljubljana Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
- Celica BIOMEDICAL; Ljubljana Slovenia
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37
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Kabachinski G, Kielar-Grevstad DM, Zhang X, James DJ, Martin TFJ. Resident CAPS on dense-core vesicles docks and primes vesicles for fusion. Mol Biol Cell 2016; 27:654-68. [PMID: 26700319 PMCID: PMC4750925 DOI: 10.1091/mbc.e15-07-0509] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/12/2015] [Accepted: 12/18/2015] [Indexed: 11/11/2022] Open
Abstract
The Ca(2+)-dependent exocytosis of dense-core vesicles in neuroendocrine cells requires a priming step during which SNARE protein complexes assemble. CAPS (aka CADPS) is one of several factors required for vesicle priming; however, the localization and dynamics of CAPS at sites of exocytosis in live neuroendocrine cells has not been determined. We imaged CAPS before, during, and after single-vesicle fusion events in PC12 cells by TIRF micro-scopy. In addition to being a resident on cytoplasmic dense-core vesicles, CAPS was present in clusters of approximately nine molecules near the plasma membrane that corresponded to docked/tethered vesicles. CAPS accompanied vesicles to the plasma membrane and was present at all vesicle exocytic events. The knockdown of CAPS by shRNA eliminated the VAMP-2-dependent docking and evoked exocytosis of fusion-competent vesicles. A CAPS(ΔC135) protein that does not localize to vesicles failed to rescue vesicle docking and evoked exocytosis in CAPS-depleted cells, showing that CAPS residence on vesicles is essential. Our results indicate that dense-core vesicles carry CAPS to sites of exocytosis, where CAPS promotes vesicle docking and fusion competence, probably by initiating SNARE complex assembly.
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Affiliation(s)
- Greg Kabachinski
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706
| | | | - Xingmin Zhang
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706
| | - Declan J James
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706
| | - Thomas F J Martin
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706
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38
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Slater CR. The functional organization of motor nerve terminals. Prog Neurobiol 2015; 134:55-103. [DOI: 10.1016/j.pneurobio.2015.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/28/2015] [Accepted: 09/05/2015] [Indexed: 12/19/2022]
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39
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Vardjan N, Parpura V, Zorec R. Loose excitation-secretion coupling in astrocytes. Glia 2015; 64:655-67. [PMID: 26358496 DOI: 10.1002/glia.22920] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/26/2015] [Indexed: 12/19/2022]
Abstract
Astrocytes play an important housekeeping role in the central nervous system. Additionally, as secretory cells, they actively participate in cell-to-cell communication, which can be mediated by membrane-bound vesicles. The gliosignaling molecules stored in these vesicles are discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This process is termed exocytosis, regulated by SNARE proteins, and triggered by elevations in cytosolic calcium levels, which are necessary and sufficient for exocytosis in astrocytes. For astrocytic exocytosis, calcium is sourced from the intracellular endoplasmic reticulum store, although its entry from the extracellular space contributes to cytosolic calcium dynamics in astrocytes. Here, we discuss calcium management in astrocytic exocytosis and the properties of the membrane-bound vesicles that store gliosignaling molecules, including the vesicle fusion machinery and kinetics of vesicle content discharge. In astrocytes, the delay between the increase in cytosolic calcium activity and the discharge of secretions from the vesicular lumen is orders of magnitude longer than that in neurons. This relatively loose excitation-secretion coupling is likely tailored to the participation of astrocytes in modulating neural network processing.
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Affiliation(s)
- Nina Vardjan
- Celica Biomedical, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy & Nanotechnology Laboratories, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama
| | - Robert Zorec
- Celica Biomedical, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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40
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Schwenen LLG, Hubrich R, Milovanovic D, Geil B, Yang J, Kros A, Jahn R, Steinem C. Resolving single membrane fusion events on planar pore-spanning membranes. Sci Rep 2015; 5:12006. [PMID: 26165860 PMCID: PMC4499801 DOI: 10.1038/srep12006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/15/2015] [Indexed: 12/15/2022] Open
Abstract
Even though a number of different in vitro fusion assays have been developed to analyze protein mediated fusion, they still only partially capture the essential features of the in vivo situation. Here we established an in vitro fusion assay that mimics the fluidity and planar geometry of the cellular plasma membrane to be able to monitor fusion of single protein-containing vesicles. As a proof of concept, planar pore-spanning membranes harboring SNARE-proteins were generated on highly ordered functionalized 1.2 μm-sized pore arrays in Si3N4. Full mobility of the membrane components was demonstrated by fluorescence correlation spectroscopy. Fusion was analyzed by two color confocal laser scanning fluorescence microscopy in a time resolved manner allowing to readily distinguish between vesicle docking, intermediate states such as hemifusion and full fusion. The importance of the membrane geometry on the fusion process was highlighted by comparing SNARE-mediated fusion with that of a minimal SNARE fusion mimetic.
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Affiliation(s)
- Lando L G Schwenen
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
| | - Raphael Hubrich
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
| | - Dragomir Milovanovic
- Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Burkhard Geil
- Institute for Physical Chemistry, University of Göttingen, Tammannstr. 6, 37077 Göttingen, Germany
| | - Jian Yang
- Leiden Institute of Chemistry - Supramolecular and Biomaterials Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Alexander Kros
- Leiden Institute of Chemistry - Supramolecular and Biomaterials Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Reinhard Jahn
- Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Claudia Steinem
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
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41
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Linares-Clemente P, Rozas JL, Mircheski J, García-Junco-Clemente P, Martínez-López JA, Nieto-González JL, Vázquez ME, Pintado CO, Fernández-Chacón R. Different dynamin blockers interfere with distinct phases of synaptic endocytosis during stimulation in motoneurones. J Physiol 2015; 593:2867-88. [PMID: 25981717 DOI: 10.1113/jp270112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 04/29/2015] [Indexed: 01/05/2023] Open
Abstract
KEY POINTS Neurotransmitter release requires a tight coupling between synaptic vesicle exocytosis and endocytosis with dynamin being a key protein in that process. We used imaging techniques to examine the time course of endocytosis at mouse motor nerve terminals expressing synaptopHluorin, a genetically encoded reporter of the synaptic vesicle cycle. We separated two sequential phases of endocytosis taking place during the stimulation train: early and late endocytosis. Freshly released synaptic vesicle proteins are preferentially retrieved during the early phase, which is very sensitive to dynasore, an inhibitor of dynamin GTPase activity. Synaptic vesicle proteins pre-existing at the plasma membrane before the stimulation are preferentially retrieved during the late phase, which is very sensitive to myristyl trimethyl ammonium bromide (MitMAB), an inhibitor of the dynamin-phospholipid interaction. ABSTRACT Synaptic endocytosis is essential at nerve terminals to maintain neurotransmitter release by exocytosis. Here, at the neuromuscular junction of synaptopHluorin (spH) transgenic mice, we have used imaging to study exo- and endocytosis occurring simultaneously during nerve stimulation. We observed two endocytosis components, which occur sequentially during stimulation. The early component of endocytosis apparently internalizes spH molecules freshly exocytosed. This component was sensitive to dynasore, a blocker of dynamin 1 GTPase activity. In contrast, this early component was resistant to myristyl trimethyl ammonium bromide (MiTMAB), a competitive agent that blocks dynamin binding to phospholipid membranes. The late component of endocytosis is likely to internalize spH molecules that pre-exist at the plasma membrane before stimulation starts. This component was blocked by MiTMAB, perhaps by impairing the binding of dynamin or other key endocytic proteins to phospholipid membranes. Our study suggests the co-existence of two sequential synaptic endocytosis steps taking place during stimulation that are susceptible to pharmacological dissection: an initial step, preferentially sensitive to dynasore, that internalizes vesicular components immediately after they are released, and a MiTMAB-sensitive step that internalizes vesicular components pre-existing at the plasma membrane surface. In addition, we report that post-stimulus endocytosis also has several components with different sensitivities to dynasore and MiTMAB.
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Affiliation(s)
- Pedro Linares-Clemente
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
| | - José L Rozas
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
| | - Josif Mircheski
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
| | - Pablo García-Junco-Clemente
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
| | - José A Martínez-López
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
| | | | - M Eugenio Vázquez
- Departamento Química Orgánica y Centro Singular de Investigación en Química Biolóxica y Materiais Moleculares (CIQUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - C Oscar Pintado
- Centro Producción y Experimentación Animal, Universidad de Sevilla, Seville, Spain
| | - Rafael Fernández-Chacón
- Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain
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A three-pool model dissecting readily releasable pool replenishment at the calyx of held. Sci Rep 2015; 5:9517. [PMID: 25825223 PMCID: PMC4379469 DOI: 10.1038/srep09517] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/06/2015] [Indexed: 12/20/2022] Open
Abstract
Although vesicle replenishment is critical in maintaining exo-endocytosis recycling, the underlying mechanisms are not well understood. Previous studies have shown that both rapid and slow endocytosis recycle into a very large recycling pool instead of within the readily releasable pool (RRP), and the time course of RRP replenishment is slowed down by more intense stimulation. This finding contradicts the calcium/calmodulin-dependence of RRP replenishment. Here we address this issue and report a three-pool model for RRP replenishment at a central synapse. Both rapid and slow endocytosis provide vesicles to a large reserve pool (RP) ~42.3 times the RRP size. When moving from the RP to the RRP, vesicles entered an intermediate pool (IP) ~2.7 times the RRP size with slow RP-IP kinetics and fast IP-RRP kinetics, which was responsible for the well-established slow and rapid components of RRP replenishment. Depletion of the IP caused the slower RRP replenishment observed after intense stimulation. These results establish, for the first time, a realistic cycling model with all parameters measured, revealing the contribution of each cycling step in synaptic transmission. The results call for modification of the current view of the vesicle recycling steps and their roles.
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Cioli C, Abdi H, Beaton D, Burnod Y, Mesmoudi S. Differences in human cortical gene expression match the temporal properties of large-scale functional networks. PLoS One 2014; 9:e115913. [PMID: 25546015 PMCID: PMC4278769 DOI: 10.1371/journal.pone.0115913] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/28/2014] [Indexed: 12/12/2022] Open
Abstract
We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring–Visual-Sensorimotor-Auditory (VSA)–comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring–Parieto-Temporo-Frontal (PTF)–comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found–with correspondence analysis–that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins–coded by genes that most differentiate the rings–were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium channels SCNA3, SCNB3, SCN9A potassium channels KCNF1, KCNG1) and facilitate spontaneous transmitter release (calcium channel CACNA1H, Synaptotagmins SYT5, Complexin CPLX3, and synaptobrevin VAMP2).
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Affiliation(s)
- Claudia Cioli
- Laboratoire d’Imagerie Biomédicale. UMR 7371/UMR S 1146, Sorbonne Universités, UPMC Université Paris 06, Paris, France
- ISC-PIF (Institut des Systèmes Complexes de Paris-Île-de-France), Paris, France
- * E-mail:
| | - Hervé Abdi
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, United States of America
| | - Derek Beaton
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, United States of America
| | - Yves Burnod
- Laboratoire d’Imagerie Biomédicale. UMR 7371/UMR S 1146, Sorbonne Universités, UPMC Université Paris 06, Paris, France
- ISC-PIF (Institut des Systèmes Complexes de Paris-Île-de-France), Paris, France
| | - Salma Mesmoudi
- ISC-PIF (Institut des Systèmes Complexes de Paris-Île-de-France), Paris, France
- Sorbonne Universités, Paris-1 Université, Equipement d’Excellence MATRICE, Paris, France
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Revelo NH, Kamin D, Truckenbrodt S, Wong AB, Reuter-Jessen K, Reisinger E, Moser T, Rizzoli SO. A new probe for super-resolution imaging of membranes elucidates trafficking pathways. ACTA ACUST UNITED AC 2014; 205:591-606. [PMID: 24862576 PMCID: PMC4033769 DOI: 10.1083/jcb.201402066] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
mCLING is a novel membrane probe for the study of membrane trafficking with demonstrated value in both live and fixed cells across a wide range of biological systems. The molecular composition of the organelles involved in membrane recycling is difficult to establish as a result of the absence of suitable labeling tools. We introduce in this paper a novel probe, named membrane-binding fluorophore-cysteine-lysine-palmitoyl group (mCLING), which labels the plasma membrane and is taken up during endocytosis. It remains attached to membranes after fixation and permeabilization and can therefore be used in combination with immunostaining and super-resolution microscopy. We applied mCLING to mammalian-cultured cells, yeast, bacteria, primary cultured neurons, Drosophila melanogaster larval neuromuscular junctions, and mammalian tissue. mCLING enabled us to study the molecular composition of different trafficking organelles. We used it to address several questions related to synaptic vesicle recycling in the auditory inner hair cells from the organ of Corti and to investigate molecular differences between synaptic vesicles that recycle actively or spontaneously in cultured neurons. We conclude that mCLING enables the investigation of trafficking membranes in a broad range of preparations.
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Affiliation(s)
- Natalia H Revelo
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, GermanyDepartment of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany International Max Planck Research School for Neurosciences, 37077 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
| | - Dirk Kamin
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, GermanyDepartment of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Sven Truckenbrodt
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, GermanyDepartment of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany International Max Planck Research School for Molecular Biology, 37077 Göttingen, Germany
| | - Aaron B Wong
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany International Max Planck Research School for Neurosciences, 37077 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
| | - Kirsten Reuter-Jessen
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
| | - Ellen Reisinger
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
| | - Tobias Moser
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, GermanyDepartment of Neuro- and Sensory Physiology; European Neuroscience Institute; and InnerEarLab and Molecular Biology of Cochlear Neurotransmission Group, Department of Otolaryngology; University Medical Center Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany Collaborative Research Center 889 and Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, 37099 Göttingen, Germany
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45
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Bretou M, Jouannot O, Fanget I, Pierobon P, Larochette N, Gestraud P, Guillon M, Emiliani V, Gasman S, Desnos C, Lennon-Duménil AM, Darchen F. Cdc42 controls the dilation of the exocytotic fusion pore by regulating membrane tension. Mol Biol Cell 2014; 25:3195-209. [PMID: 25143404 PMCID: PMC4196869 DOI: 10.1091/mbc.e14-07-1229] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
On exocytosis, membrane fusion starts with the formation of a narrow fusion pore that must expand to allow the release of secretory compounds. The GTPase Cdc42 promotes fusion pore dilation in neuroendocrine cells by controlling membrane tension. Membrane fusion underlies multiple processes, including exocytosis of hormones and neurotransmitters. Membrane fusion starts with the formation of a narrow fusion pore. Radial expansion of this pore completes the process and allows fast release of secretory compounds, but this step remains poorly understood. Here we show that inhibiting the expression of the small GTPase Cdc42 or preventing its activation with a dominant negative Cdc42 construct in human neuroendocrine cells impaired the release process by compromising fusion pore enlargement. Consequently the mode of vesicle exocytosis was shifted from full-collapse fusion to kiss-and-run. Remarkably, Cdc42-knockdown cells showed reduced membrane tension, and the artificial increase of membrane tension restored fusion pore enlargement. Moreover, inhibiting the motor protein myosin II by blebbistatin decreased membrane tension, as well as fusion pore dilation. We conclude that membrane tension is the driving force for fusion pore dilation and that Cdc42 is a key regulator of this force.
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Affiliation(s)
- Marine Bretou
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France Institut National de la Santé et de la Recherche Médicale, U932, Institut Curie, 75005 Paris, France
| | - Ouardane Jouannot
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Isabelle Fanget
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Paolo Pierobon
- Institut National de la Santé et de la Recherche Médicale, U932, Institut Curie, 75005 Paris, France
| | - Nathanaël Larochette
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Pierre Gestraud
- Institut Curie, Paris 75248, France Institut National de la Santé et de la Recherche Médicale, U900, Paris 75248, France Ecole des Mines ParisTech, Fontainebleau, 77300 France
| | - Marc Guillon
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Valentina Emiliani
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique/UPR3212, Institut des Neurosciences Cellulaires et Intégratives, Université Strasbourg, 67084 Strasbourg, France
| | - Claire Desnos
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
| | - Ana-Maria Lennon-Duménil
- Institut National de la Santé et de la Recherche Médicale, U932, Institut Curie, 75005 Paris, France
| | - François Darchen
- Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique, UMR 8250, 75270 Paris Cedex 06, France
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Application of nucleic acid-lipid conjugates for the programmable organisation of liposomal modules. Adv Colloid Interface Sci 2014; 207:290-305. [PMID: 24461711 DOI: 10.1016/j.cis.2013.12.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 11/29/2013] [Accepted: 12/19/2013] [Indexed: 01/06/2023]
Abstract
We present a critical review of recent work related to the assembly of multicompartment liposome clusters using nucleic acids as a specific recognition unit to link liposomal modules. The asymmetry in nucleic acid binding to its non-self complementary strand allows the controlled association of different compartmental modules into composite systems. These biomimetic multicompartment architectures could have future applications in chemical process control, drug delivery and synthetic biology. We assess the different methods of anchoring DNA to lipid membrane surfaces and discuss how lipid and DNA properties can be tuned to control the morphology and properties of liposome superstructures. We consider different methods for chemical communication between the contents of liposomal compartments within these clusters and assess the progress towards making this chemical mixing efficient, switchable and chemically specific. Finally, given the current state of the art, we assess the outlook for future developments towards functional modular networks of liposomes.
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47
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Schikorski T. Readily releasable vesicles recycle at the active zone of hippocampal synapses. Proc Natl Acad Sci U S A 2014; 111:5415-20. [PMID: 24706824 PMCID: PMC3986142 DOI: 10.1073/pnas.1321541111] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During the synaptic vesicle cycle, synaptic vesicles fuse with the plasma membrane and recycle for repeated exo/endocytic events. By using activity-dependent N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino) styryl) pyridinium dibromide dye uptake combined with fast (<1 s) microwave-assisted fixation followed by photoconversion and ultrastructural 3D analysis, we tracked endocytic vesicles over time, "frame by frame." The first retrieved synaptic vesicles appeared 4 s after stimulation, and these endocytic vesicles were located just above the active zone. Second, the retrieved vesicles did not show any sign of a protein coat, and coated pits were not detected. Between 10 and 30 s, large labeled vesicles appeared that had up to 5 times the size of an individual synaptic vesicle. Starting at around 20 s, these large labeled vesicles decreased in number in favor of labeled synaptic vesicles, and after 30 s, labeled vesicles redocked at the active zone. The data suggest that readily releasable vesicles are retrieved as noncoated vesicles at the active zone.
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Affiliation(s)
- Thomas Schikorski
- Department of Neuroscience, Universidad Central del Caribe, Bayamon, PR 00956
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48
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Iwabuchi S, Kakazu Y, Koh JY, Goodman KM, Harata NC. Examination of synaptic vesicle recycling using FM dyes during evoked, spontaneous, and miniature synaptic activities. J Vis Exp 2014. [PMID: 24747983 DOI: 10.3791/50557] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Synaptic vesicles in functional nerve terminals undergo exocytosis and endocytosis. This synaptic vesicle recycling can be effectively analyzed using styryl FM dyes, which reveal membrane turnover. Conventional protocols for the use of FM dyes were designed for analyzing neurons following stimulated (evoked) synaptic activity. Recently, protocols have become available for analyzing the FM signals that accompany weaker synaptic activities, such as spontaneous or miniature synaptic events. Analysis of these small changes in FM signals requires that the imaging system is sufficiently sensitive to detect small changes in intensity, yet that artifactual changes of large amplitude are suppressed. Here we describe a protocol that can be applied to evoked, spontaneous, and miniature synaptic activities, and use cultured hippocampal neurons as an example. This protocol also incorporates a means of assessing the rate of photobleaching of FM dyes, as this is a significant source of artifacts when imaging small changes in intensity.
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Affiliation(s)
- Sadahiro Iwabuchi
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine
| | - Yasuhiro Kakazu
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine
| | - Jin-Young Koh
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine
| | | | - N Charles Harata
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine;
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49
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Trouillon R, Ewing AG. Actin controls the vesicular fraction of dopamine released during extended kiss and run exocytosis. ACS Chem Biol 2014; 9:812-20. [PMID: 24400601 PMCID: PMC3985473 DOI: 10.1021/cb400665f] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
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The effect of latrunculin A, an inhibitor
of actin cross-linking,
on exocytosis in PC12 cells was investigated with single cell amperometry.
This analysis strongly suggests that the actin cytoskeleton might
be involved in regulating exocytosis, especially by mediating the
constriction of the pore. In an extended kiss-and-run release mode,
actin could actually control the fraction of neurotransmitters released
by the vesicle. This scaffold appears to contribute, with the lipid
membrane and the protein machinery, to the closing dynamics of the
pore, in competition with other forces mediating the opening of the
exocytotic channel.
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Affiliation(s)
- Raphaël Trouillon
- Department
of Chemistry and Molecular Biology, University of Gothenburg, S-41296 Gothenburg, Sweden
| | - Andrew G. Ewing
- Department
of Chemistry and Molecular Biology, University of Gothenburg, S-41296 Gothenburg, Sweden
- Department
of Chemical and Biological Engineering, Chalmers University of Technology, S-41296 Gothenburg, Sweden
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50
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Plexin-A4-dependent retrograde semaphorin 3A signalling regulates the dendritic localization of GluA2-containing AMPA receptors. Nat Commun 2014; 5:3424. [DOI: 10.1038/ncomms4424] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/11/2014] [Indexed: 01/07/2023] Open
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