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Leitz J, Wang C, Esquivies L, Pfuetzner RA, Peters JJ, Couoh-Cardel S, Wang AL, Brunger AT. Beyond the MUN domain, Munc13 controls priming and depriming of synaptic vesicles. Cell Rep 2024; 43:114026. [PMID: 38809756 PMCID: PMC11286359 DOI: 10.1016/j.celrep.2024.114026] [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: 11/20/2023] [Revised: 02/20/2024] [Accepted: 03/15/2024] [Indexed: 05/31/2024] Open
Abstract
Synaptic vesicle docking and priming are dynamic processes. At the molecular level, SNAREs (soluble NSF attachment protein receptors), synaptotagmins, and other factors are critical for Ca2+-triggered vesicle exocytosis, while disassembly factors, including NSF (N-ethylmaleimide-sensitive factor) and α-SNAP (soluble NSF attachment protein), disassemble and recycle SNAREs and antagonize fusion under some conditions. Here, we introduce a hybrid fusion assay that uses synaptic vesicles isolated from mouse brains and synthetic plasma membrane mimics. We included Munc18, Munc13, complexin, NSF, α-SNAP, and an ATP-regeneration system and maintained them continuously-as in the neuron-to investigate how these opposing processes yield fusogenic synaptic vesicles. In this setting, synaptic vesicle association is reversible, and the ATP-regeneration system produces the most synchronous Ca2+-triggered fusion, suggesting that disassembly factors perform quality control at the early stages of synaptic vesicle association to establish a highly fusogenic state. We uncovered a functional role for Munc13 ancillary to the MUN domain that alleviates an α-SNAP-dependent inhibition of Ca2+-triggered fusion.
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Affiliation(s)
- Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Chuchu Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Luis Esquivies
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Richard A Pfuetzner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - John Jacob Peters
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Sergio Couoh-Cardel
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Austin L Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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2
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Akefe IO, Saber SH, Matthews B, Venkatesh BG, Gormal RS, Blackmore DG, Alexander S, Sieriecki E, Gambin Y, Bertran-Gonzalez J, Vitale N, Humeau Y, Gaudin A, Ellis SA, Michaels AA, Xue M, Cravatt B, Joensuu M, Wallis TP, Meunier FA. The DDHD2-STXBP1 interaction mediates long-term memory via generation of saturated free fatty acids. EMBO J 2024; 43:533-567. [PMID: 38316990 PMCID: PMC10897203 DOI: 10.1038/s44318-024-00030-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 12/06/2023] [Accepted: 12/14/2023] [Indexed: 02/07/2024] Open
Abstract
The phospholipid and free fatty acid (FFA) composition of neuronal membranes plays a crucial role in learning and memory, but the mechanisms through which neuronal activity affects the brain's lipid landscape remain largely unexplored. The levels of saturated FFAs, particularly of myristic acid (C14:0), strongly increase during neuronal stimulation and memory acquisition, suggesting the involvement of phospholipase A1 (PLA1) activity in synaptic plasticity. Here, we show that genetic ablation of the PLA1 isoform DDHD2 in mice dramatically reduces saturated FFA responses to memory acquisition across the brain. Furthermore, DDHD2 loss also decreases memory performance in reward-based learning and spatial memory models prior to the development of neuromuscular deficits that mirror human spastic paraplegia. Via pulldown-mass spectrometry analyses, we find that DDHD2 binds to the key synaptic protein STXBP1. Using STXBP1/2 knockout neurosecretory cells and a haploinsufficient STXBP1+/- mouse model of human early infantile encephalopathy associated with intellectual disability and motor dysfunction, we show that STXBP1 controls targeting of DDHD2 to the plasma membrane and generation of saturated FFAs in the brain. These findings suggest key roles for DDHD2 and STXBP1 in lipid metabolism and in the processes of synaptic plasticity, learning, and memory.
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Affiliation(s)
- Isaac O Akefe
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
- Academy for Medical Education, Medical School, The University of Queensland, 288 Herston Road, 4006, Brisbane, QLD, Australia
| | - Saber H Saber
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, St Lucia, QLD, 4072, Australia
| | - Benjamin Matthews
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Bharat G Venkatesh
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Rachel S Gormal
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Daniel G Blackmore
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Suzy Alexander
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Emma Sieriecki
- School of Medical Science, University of New South Wales, Randwick, NSW, 2052, Australia
- EMBL Australia, Single Molecule Node, University of New South Wales, Sydney, 2052, Australia
| | - Yann Gambin
- School of Medical Science, University of New South Wales, Randwick, NSW, 2052, Australia
- EMBL Australia, Single Molecule Node, University of New South Wales, Sydney, 2052, Australia
| | | | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, UPR-3212 CNRS - Université de Strasbourg, Strasbourg, France
| | - Yann Humeau
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Université de Bordeaux, Bordeaux, France
| | - Arnaud Gaudin
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Sevannah A Ellis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Alysee A Michaels
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Benjamin Cravatt
- The Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia.
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, St Lucia, QLD, 4072, Australia.
| | - Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia.
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia.
- The School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
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Song J. Amygdala activity and amygdala-hippocampus connectivity: Metabolic diseases, dementia, and neuropsychiatric issues. Biomed Pharmacother 2023; 162:114647. [PMID: 37011482 DOI: 10.1016/j.biopha.2023.114647] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/04/2023] Open
Abstract
With rapid aging of the population worldwide, the number of people with dementia is dramatically increasing. Some studies have emphasized that metabolic syndrome, which includes obesity and diabetes, leads to increased risks of dementia and cognitive decline. Factors such as insulin resistance, hyperglycemia, high blood pressure, dyslipidemia, and central obesity in metabolic syndrome are associated with synaptic failure, neuroinflammation, and imbalanced neurotransmitter levels, leading to the progression of dementia. Due to the positive correlation between diabetes and dementia, some studies have called it "type 3 diabetes". Recently, the number of patients with cognitive decline due to metabolic imbalances has considerably increased. In addition, recent studies have reported that neuropsychiatric issues such as anxiety, depressive behavior, and impaired attention are common factors in patients with metabolic disease and those with dementia. In the central nervous system (CNS), the amygdala is a central region that regulates emotional memory, mood disorders, anxiety, attention, and cognitive function. The connectivity of the amygdala with other brain regions, such as the hippocampus, and the activity of the amygdala contribute to diverse neuropathological and neuropsychiatric issues. Thus, this review summarizes the significant consequences of the critical roles of amygdala connectivity in both metabolic syndromes and dementia. Further studies on amygdala function in metabolic imbalance-related dementia are needed to treat neuropsychiatric problems in patients with this type of dementia.
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Affiliation(s)
- Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Jeollanam-do, Republic of Korea.
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4
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Akefe IO, Osborne SL, Matthews B, Wallis TP, Meunier FA. Lipids and Secretory Vesicle Exocytosis. ADVANCES IN NEUROBIOLOGY 2023; 33:357-397. [PMID: 37615874 DOI: 10.1007/978-3-031-34229-5_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
In recent years, the number of studies implicating lipids in the regulation of synaptic vesicle exocytosis has risen considerably. It has become increasingly clear that lipids such as phosphoinositides, lysophospholipids, cholesterol, arachidonic acid and myristic acid play critical regulatory roles in the processes leading up to exocytosis. Lipids may affect membrane fusion reactions by altering the physical properties of the membrane, recruiting key regulatory proteins, concentrating proteins into exocytic "hotspots" or by modulating protein functions allosterically. Discrete changes in phosphoinositides concentration are involved in multiple trafficking events including exocytosis and endocytosis. Lipid-modifying enzymes such as the DDHD2 isoform of phospholipase A1 were recently shown to contribute to memory acquisition via dynamic modifications of the brain lipid landscape. Considering the increasing reports on neurodegenerative disorders associated with aberrant intracellular trafficking, an improved understanding of the control of lipid pathways is physiologically and clinically significant and will afford unique insights into mechanisms and therapeutic methods for neurodegenerative diseases. Consequently, this chapter will discuss the different classes of lipids, phospholipase enzymes, the evidence linking them to synaptic neurotransmitter release and how they act to regulate key steps in the multi-step process leading to neuronal communication and memory acquisition.
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Affiliation(s)
- Isaac O Akefe
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Shona L Osborne
- ARC Training Centre for Innovation in Biomedical Imaging Technology (CIBIT), The University of Queensland, St Lucia, QLD, Australia
| | - Benjamin Matthews
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia.
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5
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Rentería I, García-Suárez PC, Moncada-Jiménez J, Machado-Parra JP, Antunes BM, Lira FS, Jiménez-Maldonado A. Unhealthy Dieting During the COVID-19 Pandemic: An Opinion Regarding the Harmful Effects on Brain Health. Front Nutr 2022; 9:876112. [PMID: 35571935 PMCID: PMC9097874 DOI: 10.3389/fnut.2022.876112] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
Since 2020, the world has been suffering from a pandemic that has affected thousands of people regardless of socio-economic conditions, forcing the population to adopt different strategies to prevent and control the advance of the disease, one of which is social distancing. Even though social distancing is a safe strategy to reduce the spread of COVID-19, it is also the cause of a rising sedentary behavior. This behavior develops an excess of fat tissue that leads to metabolic and inflammatory disruption related to chronic diseases and mental health disorders, such as anxiety, depression, and sleep issues. Furthermore, the adoption of dietary patterns involving the consumption of ultra-processed foods, higher in fats and sugars, and the reduction of fresh and healthy foods may play a role in the progress of the disease. In this perspective, we will discuss how an unhealthy diet can affect brain function and, consequently, be a risk factor for mental health diseases.
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Affiliation(s)
- Iván Rentería
- Facultad de Deportes, Universidad Autónoma de Baja California, Ensenada, Mexico
| | - Patricia Concepción García-Suárez
- Facultad de Deportes, Universidad Autónoma de Baja California, Ensenada, Mexico
- Department of Health, Sports and Exercise Sciences, University of Kansas, Lawrence, KS, United States
| | - José Moncada-Jiménez
- Human Movement Sciences Research Center (CIMOHU), University of Costa Rica, San José, Costa Rica
| | | | | | - Fabio Santos Lira
- Exercise and Immunometabolism Research Group, Department of Physical Education, Paulista State University, UNESP, Presidente Prudente, São Paulo, Brazil
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6
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Kozlov AV, Grillari J. Pathogenesis of Multiple Organ Failure: The Impact of Systemic Damage to Plasma Membranes. Front Med (Lausanne) 2022; 9:806462. [PMID: 35372390 PMCID: PMC8964500 DOI: 10.3389/fmed.2022.806462] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/09/2022] [Indexed: 11/19/2022] Open
Abstract
Multiple organ failure (MOF) is the major cause of morbidity and mortality in intensive care patients, but the mechanisms causing this severe syndrome are still poorly understood. Inflammatory response, tissue hypoxia, immune and cellular metabolic dysregulations, and endothelial and microvascular dysfunction are the main features of MOF, but the exact mechanisms leading to MOF are still unclear. Recent progress in the membrane research suggests that cellular plasma membranes play an important role in key functions of diverse organs. Exploration of mechanisms contributing to plasma membrane damage and repair suggest that these processes can be the missing link in the development of MOF. Elevated levels of extracellular phospholipases, reactive oxygen and nitrogen species, pore-forming proteins (PFPs), and dysregulation of osmotic homeostasis occurring upon systemic inflammatory response are the major extracellular inducers of plasma membrane damage, which may simultaneously operate in different organs causing their profound dysfunction. Hypoxia activates similar processes, but they predominantly occur within the cells targeting intracellular membrane compartments and ultimately causing cell death. To combat the plasma membrane damage cells have developed several repair mechanisms, such as exocytosis, shedding, and protein-driven membrane remodeling. Analysis of knowledge on these mechanisms reveals that systemic damage to plasma membranes may be associated with potentially reversible MOF, which can be quickly recovered, if pathological stimuli are eliminated. Alternatively, it can be transformed in a non-resolving phase, if repair mechanisms are not sufficient to deal with a large damage or if the damage is extended to intracellular compartments essential for vital cellular functions.
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Affiliation(s)
- Andrey V Kozlov
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation With AUVA, LBG, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Medical University of Vienna, Vienna, Austria.,Laboratory of Navigational Redox Lipidomics and Department of Human Pathology, IM Sechenov Moscow State Medical University, Vienna, Austria
| | - Johannes Grillari
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation With AUVA, LBG, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Medical University of Vienna, Vienna, Austria.,Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
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7
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Das UN. Arachidonic Acid as Mechanotransducer of Renin Cell Baroreceptor. Nutrients 2022; 14:nu14040749. [PMID: 35215399 PMCID: PMC8874622 DOI: 10.3390/nu14040749] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 11/16/2022] Open
Abstract
For normal maintenance of blood pressure and blood volume a well-balanced renin-angiotensin-aldosterone system (RAS) is necessary. For this purpose, renin is secreted as the situation demands by the juxtaglomerular cells (also called as granular cells) that are in the walls of the afferent arterioles. Juxtaglomerular cells can sense minute changes in the blood pressure and blood volume and accordingly synthesize, store, and secrete appropriate amounts of renin. Thus, when the blood pressure and blood volume are decreased JGA cells synthesize and secrete higher amounts of renin and when the blood pressure and blood volume is increased the synthesis and secretion of renin is decreased such that homeostasis is restored. To decipher this important function, JGA cells (renin cells) need to sense and transmit the extracellular physical forces to their chromatin to control renin gene expression for appropriate renin synthesis. The changes in perfusion pressure are sensed by Integrin β1 that is transmitted to the renin cell’s nucleus via lamin A/C that produces changes in the architecture of the chromatin. This results in an alteration (either increase or decrease) in renin gene expression. Cell membrane is situated in an unique location since all stimuli need to be transmitted to the cell nucleus and messages from the DNA to the cell external environment can be conveyed only through it. This implies that cell membrane structure and integrity is essential for all cellular functions. Cell membrane is composed to proteins and lipids. The lipid components of the cell membrane regulate its (cell membrane) fluidity and the way the messages are transmitted between the cell and its environment. Of all the lipids present in the membrane, arachidonic acid (AA) forms an important constituent. In response to pressure and other stimuli, cellular and nuclear shape changes occur that render nucleus to act as an elastic mechanotransducer that produces not only changes in cell shape but also in its dynamic behavior. Cell shape changes in response to external pressure(s) result(s) in the activation of cPLA2 (cytosolic phospholipase 2)-AA pathway that stretches to recruit myosin II which produces actin-myosin cytoskeleton contractility. Released AA can undergo peroxidation and peroxidized AA binds to DNA to regulate the expression of several genes. Alterations in the perfusion pressure in the afferent arterioles produces parallel changes in the renin cell membrane leading to changes in renin release. AA and its metabolic products regulate not only the release of renin but also changes in the vanilloid type 1 (TRPV1) expression in renal sensory nerves. Thus, AA and its metabolites function as intermediate/mediator molecules in transducing changes in perfusion and mechanical pressures that involves nuclear mechanotransduction mechanism. This mechanotransducer function of AA has relevance to the synthesis and release of insulin, neurotransmitters, and other soluble mediators release by specialized and non-specialized cells. Thus, AA plays a critical role in diseases such as diabetes mellitus, hypertension, atherosclerosis, coronary heart disease, sepsis, lupus, rheumatoid arthritis, and cancer.
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Affiliation(s)
- Undurti N Das
- UND Life Sciences, 2221 NW 5th St., Battle Ground, WA 98604, USA
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8
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Das UN. Renin cell baroreceptor and arachidonic acid. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2021.110746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Villanueva J, Gimenez-Molina Y, Davletov B, Gutiérrez LM. Vesicle Fusion as a Target Process for the Action of Sphingosine and Its Derived Drugs. Int J Mol Sci 2022; 23:ijms23031086. [PMID: 35163009 PMCID: PMC8834808 DOI: 10.3390/ijms23031086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 11/16/2022] Open
Abstract
The fusion of membranes is a central part of the physiological processes involving the intracellular transport and maturation of vesicles and the final release of their contents, such as neurotransmitters and hormones, by exocytosis. Traditionally, in this process, proteins, such SNAREs have been considered the essential components of the fusion molecular machinery, while lipids have been seen as merely structural elements. Nevertheless, sphingosine, an intracellular signalling lipid, greatly increases the release of neurotransmitters in neuronal and neuroendocrine cells, affecting the exocytotic fusion mode through the direct interaction with SNAREs. Moreover, recent studies suggest that FTY-720 (Fingolimod), a sphingosine structural analogue used in the treatment of multiple sclerosis, simulates sphingosine in the promotion of exocytosis. Furthermore, this drug also induces the intracellular fusion of organelles such as dense vesicles and mitochondria causing cell death in neuroendocrine cells. Therefore, the effect of sphingosine and synthetic derivatives on the heterologous and homologous fusion of organelles can be considered as a new mechanism of action of sphingolipids influencing important physiological processes, which could underlie therapeutic uses of sphingosine derived lipids in the treatment of neurodegenerative disorders and cancers of neuronal origin such neuroblastoma.
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Affiliation(s)
- José Villanueva
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
- Correspondence: (J.V.); (L.M.G.)
| | - Yolanda Gimenez-Molina
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
| | - Bazbek Davletov
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK;
| | - Luis M. Gutiérrez
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
- Correspondence: (J.V.); (L.M.G.)
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10
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Xiong W, Shen C, Wang Z. The molecular mechanisms underlying acrosome biogenesis elucidated by gene-manipulated mice. Biol Reprod 2021; 105:789-807. [PMID: 34131698 DOI: 10.1093/biolre/ioab117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 02/05/2023] Open
Abstract
Sexual reproduction requires the fusion of two gametes in a multistep and multifactorial process termed fertilization. One of the main steps that ensures successful fertilization is acrosome reaction. The acrosome, a special kind of organelle with a cap-like structure that covers the anterior portion of sperm head, plays a key role in the process. Acrosome biogenesis begins with the initial stage of spermatid development, and it is typically divided into four successive phases: the Golgi phase, cap phase, acrosome phase, and maturation phase. The run smoothly of above processes needs an active and specific coordination between the all kinds of organelles (endoplasmic reticulum, trans-golgi network and nucleus) and cytoplasmic structures (acroplaxome and manchette). During the past two decades, an increasingly genes have been discovered to be involved in modulating acrosome formation. Most of these proteins interact with each other and show a complicated molecular regulatory mechanism to facilitate the occurrence of this event. This Review focuses on the progresses of studying acrosome biogenesis using gene-manipulated mice and highlights an emerging molecular basis of mammalian acrosome formation.
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Affiliation(s)
- Wenfeng Xiong
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chunling Shen
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhugang Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine, Rui-Jin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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11
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Wallis TP, Venkatesh BG, Narayana VK, Kvaskoff D, Ho A, Sullivan RK, Windels F, Sah P, Meunier FA. Saturated free fatty acids and association with memory formation. Nat Commun 2021; 12:3443. [PMID: 34103527 PMCID: PMC8187648 DOI: 10.1038/s41467-021-23840-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/14/2021] [Indexed: 02/05/2023] Open
Abstract
Polyunsaturated free fatty acids (FFAs) such as arachidonic acid, released by phospholipase activity on membrane phospholipids, have long been considered beneficial for learning and memory and are known modulators of neurotransmission and synaptic plasticity. However, the precise nature of other FFA and phospholipid changes in specific areas of the brain during learning is unknown. Here, using a targeted lipidomics approach to characterise FFAs and phospholipids across the rat brain, we demonstrated that the highest concentrations of these analytes were found in areas of the brain classically involved in fear learning and memory, such as the amygdala. Auditory fear conditioning led to an increase in saturated (particularly myristic and palmitic acids) and to a lesser extent unsaturated FFAs (predominantly arachidonic acid) in the amygdala and prefrontal cortex. Both fear conditioning and changes in FFA required activation of NMDA receptors. These results suggest a role for saturated FFAs in memory acquisition.
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Affiliation(s)
- Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Bharat G Venkatesh
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Vinod K Narayana
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Metabolomics Australia, Bio21 Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - David Kvaskoff
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Boehringer Ingelheim Pharma GmbH & Co. KG, Drug Discovery Sciences, Biberach an der Riß, Germany
| | - Alan Ho
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Robert K Sullivan
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - François Windels
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Joint Center for Neuroscience and Neural Engineering, and Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong Province, P. R. China
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
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12
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Sambra V, Echeverria F, Valenzuela A, Chouinard-Watkins R, Valenzuela R. Docosahexaenoic and Arachidonic Acids as Neuroprotective Nutrients throughout the Life Cycle. Nutrients 2021; 13:986. [PMID: 33803760 PMCID: PMC8003191 DOI: 10.3390/nu13030986] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 12/17/2022] Open
Abstract
The role of docosahexaenoic acid (DHA) and arachidonic acid (AA) in neurogenesis and brain development throughout the life cycle is fundamental. DHA and AA are long-chain polyunsaturated fatty acids (LCPUFA) vital for many human physiological processes, such as signaling pathways, gene expression, structure and function of membranes, among others. DHA and AA are deposited into the lipids of cell membranes that form the gray matter representing approximately 25% of the total content of brain fatty acids. Both fatty acids have effects on neuronal growth and differentiation through the modulation of the physical properties of neuronal membranes, signal transduction associated with G proteins, and gene expression. DHA and AA have a relevant role in neuroprotection against neurodegenerative pathologies such as Alzheimer's disease and Parkinson's disease, which are associated with characteristic pathological expressions as mitochondrial dysfunction, neuroinflammation, and oxidative stress. The present review analyzes the neuroprotective role of DHA and AA in the extreme stages of life, emphasizing the importance of these LCPUFA during the first year of life and in the developing/prevention of neurodegenerative diseases associated with aging.
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Affiliation(s)
- Verónica Sambra
- Department of Nutrition, Faculty of Medicine, University of Chile, Santiago 8380000, Chile; (V.S.); (F.E.)
| | - Francisca Echeverria
- Department of Nutrition, Faculty of Medicine, University of Chile, Santiago 8380000, Chile; (V.S.); (F.E.)
| | - Alfonso Valenzuela
- Faculty of Medicine, School of Nutrition, Universidad de Los Andes, Santiago 8380000, Chile;
| | - Raphaël Chouinard-Watkins
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON M5S1A8, Canada;
| | - Rodrigo Valenzuela
- Department of Nutrition, Faculty of Medicine, University of Chile, Santiago 8380000, Chile; (V.S.); (F.E.)
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON M5S1A8, Canada;
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13
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Joensuu M, Wallis TP, Saber SH, Meunier FA. Phospholipases in neuronal function: A role in learning and memory? J Neurochem 2020; 153:300-333. [PMID: 31745996 DOI: 10.1111/jnc.14918] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/29/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022]
Abstract
Despite the human brain being made of nearly 60% fat, the vast majority of studies on the mechanisms of neuronal communication which underpin cognition, memory and learning, primarily focus on proteins and/or (epi)genetic mechanisms. Phospholipids are the main component of all cellular membranes and function as substrates for numerous phospholipid-modifying enzymes, including phospholipases, which release free fatty acids (FFAs) and other lipid metabolites that can alter the intrinsic properties of the membranes, recruit and activate critical proteins, and act as lipid signalling molecules. Here, we will review brain specific phospholipases, their roles in membrane remodelling, neuronal function, learning and memory, as well as their disease implications. In particular, we will highlight key roles of unsaturated FFAs, particularly arachidonic acid, in neurotransmitter release, neuroinflammation and memory. In light of recent findings, we will also discuss the emerging role of phospholipase A1 and the creation of saturated FFAs in the brain.
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Affiliation(s)
- Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia.,Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Saber H Saber
- Laboratory of Molecular Cell Biology, Department of Zoology, Faculty of Science, Assiut University, Assiut, Egypt
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
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14
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Gimenez-Molina Y, García-Martínez V, Villanueva J, Davletov B, Gutiérrez LM. Multiple sclerosis drug FTY-720 toxicity is mediated by the heterotypic fusion of organelles in neuroendocrine cells. Sci Rep 2019; 9:18471. [PMID: 31804600 PMCID: PMC6895052 DOI: 10.1038/s41598-019-55106-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/24/2019] [Indexed: 12/29/2022] Open
Abstract
FTY-720 (Fingolimod) was one of the first compounds authorized for the treatment of multiple sclerosis. Among its other activities, this sphingosine analogue enhances exocytosis in neuroendocrine chromaffin cells, altering the quantal release of catecholamines. Surprisingly, the size of chromaffin granules is reduced within few minutes of treatment, a process that is paralleled by the homotypic fusion of granules and their heterotypic fusion with mitochondria, as witnessed by dynamic confocal and TIRF microscopy. Electron microscopy studies support these observations, revealing the fusion of several vesicles with individual mitochondria to form large, round mixed organelles. This cross-fusion is SNARE-dependent, being partially prevented by the expression of an inactive form of SNAP-25. Fused mitochondria exhibit an altered redox potential, which dramatically enhances cell death. Therefore, the cross-fusion of intracellular organelles appears to be a new mechanism to be borne in mind when considering the effect of FTY-720 on the survival of neuroendocrine cells.
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Affiliation(s)
- Yolanda Gimenez-Molina
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, 03550, Spain
| | - Virginia García-Martínez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, 03550, Spain
| | - José Villanueva
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, 03550, Spain
| | - Bazbek Davletov
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Luis M Gutiérrez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, 03550, Spain.
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15
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Arachidonic acid and lysophosphatidylcholine inhibit multiple late steps of regulated exocytosis. Biochem Biophys Res Commun 2019; 515:261-267. [PMID: 31126681 DOI: 10.1016/j.bbrc.2019.05.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 05/15/2019] [Indexed: 02/05/2023]
Abstract
The canonical Phospholipase A2 (PLA2) metabolites lysophosphatidylcholine (LPC) and arachidonic acid (ARA) affect regulated exocytosis in a wide variety of cells and are proposed to directly influence membrane merger owing to their respective spontaneous curvatures. According to the Stalk-pore hypothesis, negative curvature ARA inhibits and promotes bilayer merger upon introduction into the distal or proximal monolayers, respectively; in contrast, with positive curvature, LPC has the opposite effects. Using fully primed, release-ready native cortical secretory vesicles (CV), well-established fusion assays and standardized lipid analyses, we show that exogenous ARA and LPC, as well as their non-metabolizable analogous, ETYA and ET-18-OCH3, inhibit the docking/priming and membrane merger steps, respectively, of regulated exocytosis.
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16
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Garcia-Martinez V, Gimenez-Molina Y, Villanueva J, Darios FD, Davletov B, Gutiérrez LM. Emerging evidence for the modulation of exocytosis by signalling lipids. FEBS Lett 2018; 592:3493-3503. [PMID: 29962039 PMCID: PMC6282582 DOI: 10.1002/1873-3468.13178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/01/2018] [Accepted: 06/27/2018] [Indexed: 01/22/2023]
Abstract
Membrane fusion is a key event in exocytosis of neurotransmitters and hormones stored in intracellular vesicles. In this process, soluble N‐ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins are essential components of the exocytotic molecular machinery, while lipids have been seen traditionally as structural elements. However, the so‐called signalling lipids, such as sphingosine and arachidonic acid, interact with SNAREs and directly modulate the frequency and mode of fusion events. Interestingly, recent work has proved that the sphingosine analogue FTY‐720, used in the treatment of multiple sclerosis, mimics the effects of signalling lipids. In the present Review, we discuss recent investigations suggesting that endogenous signalling lipids and synthetic analogues can modulate important physiological aspects of secretion, such as quantal release, vesicle recruitment into active sites, vesicle transport and even organelle fusion in the cytosol. Therefore, these compounds are far from being merely structural components of cellular membranes.
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Affiliation(s)
- Virginia Garcia-Martinez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Yolanda Gimenez-Molina
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - José Villanueva
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Frederic D Darios
- Inserm, U1127, CNRS, UMR 7225, Institut du Cerveau et de la Moelle épinière, ICM, Sorbonne Université, Paris, France
| | - Bazbek Davletov
- Department of Biomedical Sciences, University of Sheffield, UK
| | - Luis M Gutiérrez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
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17
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Fecchio C, Palazzi L, de Laureto PP. α-Synuclein and Polyunsaturated Fatty Acids: Molecular Basis of the Interaction and Implication in Neurodegeneration. Molecules 2018; 23:molecules23071531. [PMID: 29941855 PMCID: PMC6099649 DOI: 10.3390/molecules23071531] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/19/2018] [Accepted: 06/23/2018] [Indexed: 12/31/2022] Open
Abstract
α-Synuclein (α-syn) is a 140-amino acid protein, the physiological function of which has yet to be clarified. It is involved in several neurodegenerative disorders, and the interaction of the protein with brain lipids plays an important role in the pathogenesis of Parkinson’s disease (PD). Polyunsaturated fatty acids (PUFA) are highly abundant in the brain where they play critical roles in neuronal membrane fluidity and permeability, serve as energy reserves and function as second messengers in cell signaling. PUFA concentration and composition in the brain are altered with age when also an increase of lipid peroxidation is observed. Considering that PD is clearly correlated with oxidative stress, PUFA abundance and composition became of great interest in neurodegeneration studies because of PUFA’s high propensity to oxidize. The high levels of the PUFA docosahexaenoic acid (DHA) in brain areas containing α-syn inclusions in patients with PD further support the hypothesis of possible interactions between α-syn and DHA. Additionally, a possible functional role of α-syn in sequestering the early peroxidation products of fatty acids was recently proposed. Here, we provide an overview of the current knowledge regarding the molecular interactions between α-syn and fatty acids and the effect exerted by the protein on their oxidative state. We highlight recent findings supporting a neuroprotective role of the protein, linking α-syn, altered lipid composition in neurodegenerative disorders and PD development.
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Affiliation(s)
- Chiara Fecchio
- Department of Biomedical Sciences, University of Padova; Padova 35131, Italy.
| | - Luana Palazzi
- Department of Pharmaceutical and Pharmacological Sciences, CRIBI, University of Padova; Padova 35131, Italy.
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18
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Lai Y, Choi UB, Leitz J, Rhee HJ, Lee C, Altas B, Zhao M, Pfuetzner RA, Wang AL, Brose N, Rhee J, Brunger AT. Molecular Mechanisms of Synaptic Vesicle Priming by Munc13 and Munc18. Neuron 2017; 95:591-607.e10. [PMID: 28772123 DOI: 10.1016/j.neuron.2017.07.004] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 05/08/2017] [Accepted: 07/06/2017] [Indexed: 11/18/2022]
Abstract
Munc13 catalyzes the transit of syntaxin from a closed complex with Munc18 into the ternary SNARE complex. Here we report a new function of Munc13, independent of Munc18: it promotes the proper syntaxin/synaptobrevin subconfiguration during assembly of the ternary SNARE complex. In cooperation with Munc18, Munc13 additionally ensures the proper syntaxin/SNAP-25 subconfiguration. In a reconstituted fusion assay with SNAREs, complexin, and synaptotagmin, inclusion of both Munc13 and Munc18 quadruples the Ca2+-triggered amplitude and achieves Ca2+ sensitivity at near-physiological concentrations. In Munc13-1/2 double-knockout neurons, expression of a constitutively open mutant of syntaxin could only minimally restore neurotransmitter release relative to Munc13-1 rescue. Together, the physiological functions of Munc13 may be related to regulation of proper SNARE complex assembly.
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Affiliation(s)
- Ying Lai
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Ucheor B Choi
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Hong Jun Rhee
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Choongku Lee
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Bekir Altas
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Minglei Zhao
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Richard A Pfuetzner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Austin L Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University, Stanford, CA 94305, USA; Department of Photon Science, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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19
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Thomas MH, Paris C, Magnien M, Colin J, Pelleïeux S, Coste F, Escanyé MC, Pillot T, Olivier JL. Dietary arachidonic acid increases deleterious effects of amyloid-β oligomers on learning abilities and expression of AMPA receptors: putative role of the ACSL4-cPLA 2 balance. ALZHEIMERS RESEARCH & THERAPY 2017; 9:69. [PMID: 28851448 PMCID: PMC5576249 DOI: 10.1186/s13195-017-0295-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 08/03/2017] [Indexed: 01/14/2023]
Abstract
Background Polyunsaturated fatty acids play a crucial role in neuronal function, and the modification of these compounds in the brain could have an impact on neurodegenerative diseases such as Alzheimer’s disease. Despite the fact that arachidonic acid is the second foremost polyunsaturated fatty acid besides docosahexaenoic acid, its role and the regulation of its transfer and mobilization in the brain are poorly known. Methods Two groups of 39 adult male BALB/c mice were fed with an arachidonic acid-enriched diet or an oleic acid-enriched diet, respectively, for 12 weeks. After 10 weeks on the diet, mice received intracerebroventricular injections of either NaCl solution or amyloid-β peptide (Aβ) oligomers. Y-maze and Morris water maze tests were used to evaluate short- and long-term memory. At 12 weeks on the diet, mice were killed, and blood, liver, and brain samples were collected for lipid and protein analyses. Results We found that the administration of an arachidonic acid-enriched diet for 12 weeks induced short-term memory impairment and increased deleterious effects of Aβ oligomers on learning abilities. These cognitive alterations were associated with modifications of expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, postsynaptic density protein 95, and glial fibrillary acidic protein in mouse cortex or hippocampus by the arachidonic acid-enriched diet and Aβ oligomer administration. This diet also led to an imbalance between the main ω-6 fatty acids and the ω-3 fatty acids in favor of the first one in erythrocytes and the liver as well as in the hippocampal and cortical brain structures. In the cortex, the dietary arachidonic acid also induced an increase of arachidonic acid-containing phospholipid species in phosphatidylserine class, whereas intracerebroventricular injections modified several arachidonic acid- and docosahexaenoic acid-containing species in the four phospholipid classes. Finally, we observed that dietary arachidonic acid decreased the expression of the neuronal form of acyl-coenzyme A synthetase 4 in the hippocampus and increased the cytosolic phospholipase A2 activation level in the cortices of the mice. Conclusions Dietary arachidonic acid could amplify Aβ oligomer neurotoxicity. Its consumption could constitute a risk factor for Alzheimer’s disease in humans and should be taken into account in future preventive strategies. Its deleterious effect on cognitive capacity could be linked to the balance between arachidonic acid-mobilizing enzymes. Electronic supplementary material The online version of this article (doi:10.1186/s13195-017-0295-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mélanie H Thomas
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France
| | - Cédric Paris
- Laboratory of Biomolecules Engineering (LIBio), Lorraine University, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France
| | - Mylène Magnien
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France
| | - Julie Colin
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France
| | - Sandra Pelleïeux
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France.,Biochemistry Department, Central Hospital, University Hospitals of Nancy, 24, avenue du Mal de Lattre de Tassigny, CO n°34, F-54018, Nancy, France
| | - Florence Coste
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France
| | - Marie-Christine Escanyé
- Biochemistry Department, Central Hospital, University Hospitals of Nancy, 24, avenue du Mal de Lattre de Tassigny, CO n°34, F-54018, Nancy, France
| | - Thierry Pillot
- Synaging SAS, 2, rue du Doyen Marcel Roubault, 54518, Vandoeuvre-les-Nancy, France
| | - Jean-Luc Olivier
- Research unit on Animals and Functionality of Animal Products (URAFPA), Lorraine University, EA 3998, USC INRA 0340, 2, Avenue de la Forêt de Haye, TSA40602, F-54518, Vandœuvre-lès-Nancy, France. .,Biochemistry Department, Central Hospital, University Hospitals of Nancy, 24, avenue du Mal de Lattre de Tassigny, CO n°34, F-54018, Nancy, France.
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20
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Jakhanwal S, Lee CT, Urlaub H, Jahn R. An activated Q-SNARE/SM protein complex as a possible intermediate in SNARE assembly. EMBO J 2017; 36:1788-1802. [PMID: 28483813 DOI: 10.15252/embj.201696270] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 01/15/2023] Open
Abstract
Assembly of the SNARE proteins syntaxin1, SNAP25, and synaptobrevin into a SNARE complex is essential for exocytosis in neurons. For efficient assembly, SNAREs interact with additional proteins but neither the nature of the intermediates nor the sequence of protein assembly is known. Here, we have characterized a ternary complex between syntaxin1, SNAP25, and the SM protein Munc18-1 as a possible acceptor complex for the R-SNARE synaptobrevin. The ternary complex binds synaptobrevin with fast kinetics, resulting in the rapid formation of a fully zippered SNARE complex to which Munc18-1 remains tethered by the N-terminal domain of syntaxin1. Intriguingly, only one of the synaptobrevin truncation mutants (Syb1-65) was able to bind to the syntaxin1:SNAP25:Munc18-1 complex, suggesting either a cooperative zippering mechanism that proceeds bidirectionally or the progressive R-SNARE binding via an SM template. Moreover, the complex is resistant to disassembly by NSF Based on these findings, we consider the ternary complex as a strong candidate for a physiological intermediate in SNARE assembly.
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Affiliation(s)
- Shrutee Jakhanwal
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Chung-Tien Lee
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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21
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Dabral D, Coorssen JR. Phospholipase A 2: Potential roles in native membrane fusion. Int J Biochem Cell Biol 2017; 85:1-5. [PMID: 28131878 DOI: 10.1016/j.biocel.2017.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/29/2016] [Accepted: 01/22/2017] [Indexed: 12/22/2022]
Abstract
Membrane fusion is a fundamental molecular mechanism by which two apposed membrane bilayers coalesce in rapid, transient steps that enable the successive merging of the outer and inner leaflets allowing lipid intermixing and subsequent mixing of the two previously separate compartments. The actual membrane merger mechanism - fusion, by definition - is conceptualized to be protein- or lipid-centric. According to the widely vetted stalk-pore hypothesis, membrane fusion proceeds via high curvature lipid intermediates. By cleaving membrane phospholipids at the sn-2 position, Phospholipase A2 generates metabolites that exert spontaneous curvature stress (both negative and positive) on the membrane, thus influencing local membrane bending by altering the packing and conformation of lipids and proteins, respectively. Such changes could potentially modulate priming and attachment/docking steps that precede fusion, as well as the membrane merger steps per se.
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Affiliation(s)
- Deepti Dabral
- Molecular Physiology, and Molecular Medicine Research Group, School of Medicine, Western Sydney University, Campbelltown Campus, Penrith, NSW 2751, Australia
| | - Jens R Coorssen
- Faculty of Graduate Studies and the Departments of Health Sciences and Biological Sciences, Brock University,St. Catharines, ON L2S 3A1, Canada.
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22
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Thomas MH, Pelleieux S, Vitale N, Olivier JL. Dietary arachidonic acid as a risk factor for age-associated neurodegenerative diseases: Potential mechanisms. Biochimie 2016; 130:168-177. [PMID: 27473185 DOI: 10.1016/j.biochi.2016.07.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 07/24/2016] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease and associated diseases constitute a major public health concern worldwide. Nutrition-based, preventive strategies could possibly be effective in delaying the occurrence of these diseases and lower their prevalence. Arachidonic acid is the second major polyunsaturated fatty acid (PUFA) and several studies support its involvement in Alzheimer's disease. The objective of this review is to examine how dietary arachidonic acid contributes to Alzheimer's disease mechanisms and therefore to its prevention. First, we explore the sources of neuronal arachidonic acid that could potentially originate from either the conversion of linoleic acid, or from dietary sources and transfer across the blood-brain-barrier. In a second part, a brief overview of the role of the two main agents of Alzheimer's disease, tau protein and Aβ peptide is given, followed by the examination of the relationship between arachidonic acid and the disease. Third, the putative mechanisms by which arachidonic acid could influence Alzheimer's disease occurrence and evolution are presented. The conclusion is devoted to what remains to be determined before integrating arachidonic acid in the design of preventive strategies against Alzheimer's disease and other neurodegenerative diseases.
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Affiliation(s)
- Mélanie H Thomas
- Unité de Recherche Aliment et Fonctionnalité des Produits Animaux (URAFPA), INRA USC 0340, Université de Lorraine, Nancy, France
| | - Sandra Pelleieux
- Unité de Recherche Aliment et Fonctionnalité des Produits Animaux (URAFPA), INRA USC 0340, Université de Lorraine, Nancy, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR CNRS 3212, Université de Strasbourg, Strasbourg, France
| | - Jean Luc Olivier
- Unité de Recherche Aliment et Fonctionnalité des Produits Animaux (URAFPA), INRA USC 0340, Université de Lorraine, Nancy, France.
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Narayana V, Tomatis VM, Wang T, Kvaskoff D, Meunier F. Profiling of Free Fatty Acids Using Stable Isotope Tagging Uncovers a Role for Saturated Fatty Acids in Neuroexocytosis. ACTA ACUST UNITED AC 2015; 22:1552-1561. [DOI: 10.1016/j.chembiol.2015.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/02/2015] [Accepted: 09/24/2015] [Indexed: 01/18/2023]
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Ziegler AB, Ménagé C, Grégoire S, Garcia T, Ferveur JF, Bretillon L, Grosjean Y. Lack of Dietary Polyunsaturated Fatty Acids Causes Synapse Dysfunction in the Drosophila Visual System. PLoS One 2015; 10:e0135353. [PMID: 26308084 PMCID: PMC4550417 DOI: 10.1371/journal.pone.0135353] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/22/2015] [Indexed: 01/25/2023] Open
Abstract
Polyunsaturated fatty acids (PUFAs) are essential nutrients for animals and necessary for the normal functioning of the nervous system. A lack of PUFAs can result from the consumption of a deficient diet or genetic factors, which impact PUFA uptake and metabolism. Both can cause synaptic dysfunction, which is associated with numerous disorders. However, there is a knowledge gap linking these neuronal dysfunctions and their underlying molecular mechanisms. Because of its genetic manipulability and its easy, fast, and cheap breeding, Drosophila melanogaster has emerged as an excellent model organism for genetic screens, helping to identify the genetic bases of such events. As a first step towards the understanding of PUFA implications in Drosophila synaptic physiology we designed a breeding medium containing only very low amounts of PUFAs. We then used the fly’s visual system, a well-established model for studying signal transmission and neurological disorders, to measure the effects of a PUFA deficiency on synaptic function. Using both visual performance and eye electrophysiology, we found that PUFA deficiency strongly affected synaptic transmission in the fly’s visual system. These defects were rescued by diets containing omega-3 or omega-6 PUFAs alone or in combination. In summary, manipulating PUFA contents in the fly’s diet was powerful to investigate the role of these nutrients on the fly´s visual synaptic function. This study aims at showing how the first visual synapse of Drosophila can serve as a simple model to study the effects of PUFAs on synapse function. A similar approach could be further used to screen for genetic factors underlying the molecular mechanisms of synaptic dysfunctions associated with altered PUFA levels.
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Affiliation(s)
- Anna B. Ziegler
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
- * E-mail: (ABZ); (YG)
| | - Cindy Ménagé
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
| | - Stéphane Grégoire
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
| | - Thibault Garcia
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
| | - Jean-François Ferveur
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
| | - Lionel Bretillon
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
| | - Yael Grosjean
- CNRS, UMR6265 CSGA, 21000, Dijon, France
- INRA, UMR1324 CSGA, 21000, Dijon, France
- Université de Bourgogne-Franche-Comté, UMR CSGA, 21000, Dijon, France
- * E-mail: (ABZ); (YG)
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García-Martínez V, Montes MA, Villanueva J, Gimenez-Molina Y, de Toledo GA, Gutiérrez LM. Sphingomyelin derivatives increase the frequency of microvesicle and granule fusion in chromaffin cells. Neuroscience 2015; 295:117-25. [PMID: 25813703 DOI: 10.1016/j.neuroscience.2015.03.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
Sphingomyelin derivatives like sphingosine have been shown to enhance secretion in a variety of systems, including neuroendocrine and neuronal cells. By studying the mechanisms underlying this effect, we demonstrate here that sphingomyelin rafts co-localize strongly with synaptosomal-associated protein of 25Kda (SNAP-25) clusters in cultured bovine chromaffin cells and that they appear to be linked in a dynamic manner. In functional terms, when cultured rat chromaffin cells are treated with sphingomyelinase (SMase), producing sphingomyelin derivatives, the secretion elicited by repetitive depolarizations is enhanced. This increase was independent of cell size and it was significant 15min after initiating stimulation. Interestingly, by evaluating the membrane capacitance we found that the events in control untreated cells corresponded to two populations of microvesicles and granules, and the fusion of both these populations is clearly enhanced after treatment with SMase. Furthermore, SMase does not increase the size of chromaffin granules. Together, these results strongly suggest that SNARE-mediated exocytosis is enhanced by the generation of SMase derivatives, reflecting an increase in the frequency of fusion of both microvesicles and chromaffin granules rather than an increase in the size of these vesicles.
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Affiliation(s)
- V García-Martínez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - M A Montes
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
| | - J Villanueva
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - Y Gimenez-Molina
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain
| | - G A de Toledo
- Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain
| | - L M Gutiérrez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante 03550, Spain.
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Enrich C, Rentero C, Hierro A, Grewal T. Role of cholesterol in SNARE-mediated trafficking on intracellular membranes. J Cell Sci 2015; 128:1071-81. [PMID: 25653390 DOI: 10.1242/jcs.164459] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cell surface delivery of extracellular matrix (ECM) and integrins is fundamental for cell migration in wound healing and during cancer cell metastasis. This process is not only driven by several soluble NSF attachment protein (SNAP) receptor (SNARE) proteins, which are key players in vesicle transport at the cell surface and intracellular compartments, but is also tightly modulated by cholesterol. Cholesterol-sensitive SNAREs at the cell surface are relatively well characterized, but it is less well understood how altered cholesterol levels in intracellular compartments impact on SNARE localization and function. Recent insights from structural biology, protein chemistry and cell microscopy have suggested that a subset of the SNAREs engaged in exocytic and retrograde pathways dynamically 'sense' cholesterol levels in the Golgi and endosomal membranes. Hence, the transport routes that modulate cellular cholesterol distribution appear to trigger not only a change in the location and functioning of SNAREs at the cell surface but also in endomembranes. In this Commentary, we will discuss how disrupted cholesterol transport through the Golgi and endosomal compartments ultimately controls SNARE-mediated delivery of ECM and integrins to the cell surface and, consequently, cell migration.
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Affiliation(s)
- Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Carles Rentero
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Aitor Hierro
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
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Abstract
Synaptic vesicles release their vesicular contents to the extracellular space by Ca(2+)-triggered exocytosis. The Ca(2+)-triggered exocytotic process is regulated by synaptotagmin (Syt), a vesicular Ca(2+)-binding C2 domain protein. Synaptotagmin 1 (Syt1), the most studied major isoform among 16 Syt isoforms, mediates Ca(2+)-triggered synaptic vesicle exocytosis by interacting with the target membranes and SNARE/complexin complex. In synapses of the central nervous system, synaptobrevin 2, a major vesicular SNARE protein, forms a ternary SNARE complex with the plasma membrane SNARE proteins, syntaxin 1 and SNAP25. The affinities of Ca(2+)-dependent interactions between Syt1 and its targets (i.e., SNARE complexes and membranes) are well correlated with the efficacies of the corresponding exocytotic processes. Therefore, different SNARE protein isoforms and membrane lipids, which interact with Syt1 with various affinities, are capable of regulating the efficacy of Syt1-mediated exocytosis. Otoferlin, another type of vesicular C2 domain protein that binds to the membrane in a Ca(2+)-dependent manner, is also involved in the Ca(2+)-triggered synaptic vesicle exocytosis in auditory hair cells. However, the functions of otoferlin in the exocytotic process are not well understood. In addition, at least five different types of synaptic vesicle proteins such as synaptic vesicle protein 2, cysteine string protein α, rab3, synapsin, and a group of proteins containing four transmembrane regions, which includes synaptophysin, synaptogyrin, and secretory carrier membrane protein, are involved in modulating the exocytotic process by regulating the formation and trafficking of synaptic vesicles.
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Affiliation(s)
- Ok-Ho Shin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas
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Ibarguren M, López DJ, Escribá PV. The effect of natural and synthetic fatty acids on membrane structure, microdomain organization, cellular functions and human health. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1518-28. [DOI: 10.1016/j.bbamem.2013.12.021] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/20/2013] [Accepted: 12/24/2013] [Indexed: 02/06/2023]
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Truchet S, Chat S, Ollivier-Bousquet M. Milk secretion: The role of SNARE proteins. J Mammary Gland Biol Neoplasia 2014; 19:119-30. [PMID: 24264376 DOI: 10.1007/s10911-013-9311-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/13/2013] [Indexed: 12/21/2022] Open
Abstract
During lactation, polarized mammary epithelial secretory cells (MESCs) secrete huge quantities of the nutrient molecules that make up milk, i.e. proteins, fat globules and soluble components such as lactose and minerals. Some of these nutrients are only produced by the MESCs themselves, while others are to a great extent transferred from the blood. MESCs can thus be seen as a crossroads for both the uptake and the secretion with cross-talks between intracellular compartments that enable spatial and temporal coordination of the secretion of the milk constituents. Although the physiology of lactation is well understood, the molecular mechanisms underlying the secretion of milk components remain incompletely characterized. Major milk proteins, namely caseins, are secreted by exocytosis, while the milk fat globules are released by budding, being enwrapped by the apical plasma membrane. Prolactin, which stimulates the transcription of casein genes, also induces the production of arachidonic acid, leading to accelerated casein transport and/or secretion. Because of their ability to form complexes that bridge two membranes and promote their fusion, SNARE (Soluble N-ethylmaleimide-Sensitive Factor Attachment Protein Receptor) proteins are involved in almost all intracellular trafficking steps and exocytosis. As SNAREs can bind arachidonic acid, they could be the effectors of the secretagogue effect of prolactin in MESCs. Indeed, some SNAREs have been observed between secretory vesicles and lipid droplets suggesting that these proteins could not only orchestrate the intracellular trafficking of milk components but also act as key regulators for both the coupling and coordination of milk product secretion in response to hormones.
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Affiliation(s)
- Sandrine Truchet
- INRA, UR1196 Génomique et Physiologie de la Lactation, 78352, Jouy-en-Josas Cedex, France,
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Lipid metabolites enhance secretion acting on SNARE microdomains and altering the extent and kinetics of single release events in bovine adrenal chromaffin cells. PLoS One 2013; 8:e75845. [PMID: 24073281 PMCID: PMC3779176 DOI: 10.1371/journal.pone.0075845] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 08/22/2013] [Indexed: 01/03/2023] Open
Abstract
Lipid molecules such as arachidonic acid (AA) and sphingolipid metabolites have been implicated in modulation of neuronal and endocrine secretion. Here we compare the effects of these lipids on secretion from cultured bovine chromaffin cells. First, we demonstrate that exogenous sphingosine and AA interact with the secretory apparatus as confirmed by FRET experiments. Examination of plasma membrane SNARE microdomains and chromaffin granule dynamics using total internal reflection fluorescent microscopy (TIRFM) suggests that sphingosine production promotes granule tethering while arachidonic acid promotes full docking. Our analysis of single granule release kinetics by amperometry demonstrated that both sphingomyelinase and AA treatments enhanced drastically the amount of catecholamines released per individual event by either altering the onset phase of or by prolonging the off phase of single granule catecholamine release kinetics. Together these results demonstrate that the kinetics and extent of the exocytotic fusion pore formation can be modulated by specific signalling lipids through related functional mechanisms.
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Gardai SJ, Mao W, Schüle B, Babcock M, Schoebel S, Lorenzana C, Alexander J, Kim S, Glick H, Hilton K, Fitzgerald JK, Buttini M, Chiou SS, McConlogue L, Anderson JP, Schenk DB, Bard F, Langston JW, Yednock T, Johnston JA. Elevated alpha-synuclein impairs innate immune cell function and provides a potential peripheral biomarker for Parkinson's disease. PLoS One 2013; 8:e71634. [PMID: 24058406 PMCID: PMC3751933 DOI: 10.1371/journal.pone.0071634] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 07/01/2013] [Indexed: 12/14/2022] Open
Abstract
Alpha-synuclein protein is strongly implicated in the pathogenesis Parkinson's disease. Increased expression of α-synuclein due to genetic multiplication or point mutations leads to early onset disease. While α-synuclein is known to modulate membrane vesicle dynamics, it is not clear if this activity is involved in the pathogenic process or if measurable physiological effects of α-synuclein over-expression or mutation exist in vivo. Macrophages and microglia isolated from BAC α-synuclein transgenic mice, which overexpress α-synuclein under regulation of its own promoter, express α-synuclein and exhibit impaired cytokine release and phagocytosis. These processes were affected in vivo as well, both in peritoneal macrophages and microglia in the CNS. Extending these findings to humans, we found similar results with monocytes and fibroblasts isolated from idiopathic or familial Parkinson's disease patients compared to age-matched controls. In summary, this paper provides 1) a new animal model to measure α-synuclein dysfunction; 2) a cellular system to measure synchronized mobilization of α-synuclein and its functional interactions; 3) observations regarding a potential role for innate immune cell function in the development and progression of Parkinson's disease and other human synucleinopathies; 4) putative peripheral biomarkers to study and track these processes in human subjects. While altered neuronal function is a primary issue in PD, the widespread consequence of abnormal α-synuclein expression in other cell types, including immune cells, could play an important role in the neurodegenerative progression of PD and other synucleinopathies. Moreover, increased α-synuclein and altered phagocytosis may provide a useful biomarker for human PD.
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Affiliation(s)
- Shyra J. Gardai
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
- * E-mail:
| | - Wenxian Mao
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Birgitt Schüle
- The Parkinson's Institute, Sunnyvale, California, United States of America
| | - Michael Babcock
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Sue Schoebel
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Carlos Lorenzana
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Jeff Alexander
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Sam Kim
- The Parkinson's Institute, Sunnyvale, California, United States of America
| | - Heather Glick
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Kathryn Hilton
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - J. Kent Fitzgerald
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Manuel Buttini
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - San-San Chiou
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Lisa McConlogue
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - John P. Anderson
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Dale B. Schenk
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Frederique Bard
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | | | - Ted Yednock
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Jennifer A. Johnston
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
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Ma C, Su L, Seven AB, Xu Y, Rizo J. Reconstitution of the vital functions of Munc18 and Munc13 in neurotransmitter release. Science 2012; 339:421-5. [PMID: 23258414 DOI: 10.1126/science.1230473] [Citation(s) in RCA: 294] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Neurotransmitter release depends critically on Munc18-1, Munc13, the Ca(2+) sensor synaptotagmin-1, and the soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptors (SNAREs) syntaxin-1, synaptobrevin, and SNAP-25. In vitro reconstitutions have shown that syntaxin-1-SNAP-25 liposomes fuse efficiently with synaptobrevin liposomes in the presence of synaptotagmin-1-Ca(2+), but neurotransmitter release also requires Munc18-1 and Munc13 in vivo. We found that Munc18-1 could displace SNAP-25 from syntaxin-1 and that fusion of syntaxin-1-Munc18-1 liposomes with synaptobrevin liposomes required Munc13, in addition to SNAP-25 and synaptotagmin-1-Ca(2+). Moreover, when starting with syntaxin-1-SNAP-25 liposomes, NSF-α-SNAP disassembled the syntaxin-1-SNAP-25 heterodimers and abrogated fusion, which then required Munc18-1 and Munc13. We propose that fusion does not proceed through syntaxin-1-SNAP-25 heterodimers but starts with the syntaxin-1-Munc18-1 complex; Munc18-1 and Munc13 then orchestrate membrane fusion together with the SNAREs and synaptotagmin-1-Ca(2+) in an NSF- and SNAP-resistant manner.
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Affiliation(s)
- Cong Ma
- Key Laboratory of Molecular Biophysics, Ministry of Education, and Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan 430074, China.
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Abstract
The mammary epithelium coordinates the uptake of milk precursors and the transport of milk components in order to produce milk of relatively constant composition at a particular stage of lactation, as long as the mammary gland is healthy. The mammary epithelial cell controls the uptake of blood-borne molecules at its basal side and the release of products into milk at its apical side, through mechanisms of internalization (endocytosis) and mechanisms of release (exocytosis). These events are strictly dependent on the physiological stage of the mammary gland. This review addresses the mechanisms responsible for these processes and points out new questions that remain to be answered concerning possible interconnections between them, for an optimal milk secretion.
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Abstract
Exocytosis is a multistage process involving a merger between the vesicle and the plasma membranes, leading to the formation of a fusion pore, a channel, through which secretions are released from the vesicle to the cell exterior. A stimulus may influence the pore by either dilating it completely (full-fusion exocytosis) or mediating a reversible closure (transient exocytosis). In neurons, these transitions are short-lived and not accessible for experimentation. However, in some neuroendocrine cells, initial fusion pores may reopen several hundred times, indicating their stability. Moreover, these pores are too narrow to pass luminal molecules to the extracellular space, termed release-unproductive. However, on stimulation, their diameter dilates, initiating the release of cargo without de novo fusion pore formation. To explain the stability of the initial narrow fusion pores, anisotropic membrane constituents with non-axisymmetrical shape were proposed to accumulate in the fusion pore membrane. Although the nature of these is unclear, they may consist of lipids and proteins, including SNAREs, which may facilitate and regulate the pre- and post-fusional stages of exocytosis. In the future, a more detailed insight into the molecular control of fusion pore stabilization and regulation will generate a better understanding of fusion pore physiology in health and disease.
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Reverter M, Rentero C, de Muga SV, Alvarez-Guaita A, Mulay V, Cairns R, Wood P, Monastyrskaya K, Pol A, Tebar F, Blasi J, Grewal T, Enrich C. Cholesterol transport from late endosomes to the Golgi regulates t-SNARE trafficking, assembly, and function. Mol Biol Cell 2012; 22:4108-23. [PMID: 22039070 PMCID: PMC3204072 DOI: 10.1091/mbc.e11-04-0332] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This study shows that impaired cholesterol egress from late endosomes in cells with high annexin A6 levels is associated with altered soluble N-ethylmaleimide–sensitive fusion protein 23 (SNAP23) and syntaxin-4 cellular distribution and assembly and accumulation in Golgi membranes. This correlates with reduced secretion of cargo along the constitutive and SNAP23/syntaxin-4–dependent secretory pathway. Cholesterol regulates plasma membrane (PM) association and functioning of syntaxin-4 and soluble N-ethylmaleimide-sensitive fusion protein 23 (SNAP23) in the secretory pathway. However, the molecular mechanism and cellular cholesterol pools that determine the localization and assembly of these target membrane SNAP receptors (t-SNAREs) are largely unknown. We recently demonstrated that high levels of annexin A6 (AnxA6) induce accumulation of cholesterol in late endosomes, thereby reducing cholesterol in the Golgi and PM. This leads to an impaired supply of cholesterol needed for cytosolic phospholipase A2 (cPLA2) to drive Golgi vesiculation and caveolin transport to the cell surface. Using AnxA6-overexpressing cells as a model for cellular cholesterol imbalance, we identify impaired cholesterol egress from late endosomes and diminution of Golgi cholesterol as correlating with the sequestration of SNAP23/syntaxin-4 in Golgi membranes. Pharmacological accumulation of late endosomal cholesterol and cPLA2 inhibition induces a similar phenotype in control cells with low AnxA6 levels. Ectopic expression of Niemann-Pick C1 (NPC1) or exogenous cholesterol restores the location of SNAP23 and syntaxin-4 within the PM. Importantly, AnxA6-mediated mislocalization of these t-SNAREs correlates with reduced secretion of cargo via the SNAP23/syntaxin-4–dependent constitutive exocytic pathway. We thus conclude that inhibition of late endosomal export and Golgi cholesterol depletion modulate t-SNARE localization and functioning along the exocytic pathway.
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Affiliation(s)
- Meritxell Reverter
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Universitat de Barcelona, 08036 Barcelona, Spain
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37
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Reverter M, Rentero C, de Muga SV, Alvarez-Guaita A, Mulay V, Cairns R, Wood P, Monastyrskaya K, Pol A, Tebar F, Blasi J, Grewal T, Enrich C. Cholesterol transport from late endosomes to the Golgi regulates t-SNARE trafficking, assembly, and function. Mol Biol Cell 2011. [DOI: 10.1091/mbc.e11-04-0332r] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cholesterol regulates plasma membrane (PM) association and functioning of syntaxin-4 and soluble N-ethylmaleimide-sensitive fusion protein 23 (SNAP23) in the secretory pathway. However, the molecular mechanism and cellular cholesterol pools that determine the localization and assembly of these target membrane SNAP receptors (t-SNAREs) are largely unknown. We recently demonstrated that high levels of annexin A6 (AnxA6) induce accumulation of cholesterol in late endosomes, thereby reducing cholesterol in the Golgi and PM. This leads to an impaired supply of cholesterol needed for cytosolic phospholipase A2(cPLA2) to drive Golgi vesiculation and caveolin transport to the cell surface. Using AnxA6-overexpressing cells as a model for cellular cholesterol imbalance, we identify impaired cholesterol egress from late endosomes and diminution of Golgi cholesterol as correlating with the sequestration of SNAP23/syntaxin-4 in Golgi membranes. Pharmacological accumulation of late endosomal cholesterol and cPLA2inhibition induces a similar phenotype in control cells with low AnxA6 levels. Ectopic expression of Niemann-Pick C1 (NPC1) or exogenous cholesterol restores the location of SNAP23 and syntaxin-4 within the PM. Importantly, AnxA6-mediated mislocalization of these t-SNAREs correlates with reduced secretion of cargo via the SNAP23/syntaxin-4–dependent constitutive exocytic pathway. We thus conclude that inhibition of late endosomal export and Golgi cholesterol depletion modulate t-SNARE localization and functioning along the exocytic pathway.
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Affiliation(s)
- Meritxell Reverter
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Carles Rentero
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Sandra Vilà de Muga
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Anna Alvarez-Guaita
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Vishwaroop Mulay
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Rose Cairns
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Peta Wood
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Katia Monastyrskaya
- Urology Research Laboratory, Department of Clinical Research, University of Bern, 3000 Bern 9, Switzerland
| | - Albert Pol
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Francesc Tebar
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Joan Blasi
- Department of Pathology and Experimental Therapeutics, IDIBELL–University of Barcelona, 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Carlos Enrich
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
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38
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Shi L, Kümmel D, Coleman J, Melia TJ, Giraudo CG. Dual roles of Munc18-1 rely on distinct binding modes of the central cavity with Stx1A and SNARE complex. Mol Biol Cell 2011; 22:4150-60. [PMID: 21900493 PMCID: PMC3204075 DOI: 10.1091/mbc.e11-02-0150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Sec1/Munc18 proteins play a fundamental role in multiple steps of intracellular membrane trafficking. Dual functions have been attributed to Munc18-1: it can act as a chaperone when it interacts with monomeric syntaxin 1A, and it can activate soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) for membrane fusion when it binds to SNARE complexes. Although both modes of binding involve the central cavity of Munc18-1, their precise molecular mechanisms of action are not fully understood. In this paper, we describe a novel Munc18-1 mutant in the central cavity that showed a reduced interaction with syntaxin 1A and impaired chaperone function, but still bound to assembled SNARE complexes and promoted liposome fusion and secretion in neuroendocrine cells. Soluble syntaxin 1A H3 domain partially blocks Munc18-1 activation of liposome fusion by occupying the Munc18-1 central cavity. Our findings lead us to propose a transition model between the two distinct binding modes by which Munc18 can control and assist in SNARE-complex assembly during neurotransmitter release.
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Affiliation(s)
- Lei Shi
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520, USA
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39
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Zhang C, Li A, Gao S, Zhang X, Xiao H. The TIP30 protein complex, arachidonic acid and coenzyme A are required for vesicle membrane fusion. PLoS One 2011; 6:e21233. [PMID: 21731680 PMCID: PMC3123320 DOI: 10.1371/journal.pone.0021233] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/24/2011] [Indexed: 01/20/2023] Open
Abstract
Efficient membrane fusion has been successfully mimicked in vitro using artificial membranes and a number of cellular proteins that are currently known to participate in membrane fusion. However, these proteins are not sufficient to promote efficient fusion between biological membranes, indicating that critical fusogenic factors remain unidentified. We have recently identified a TIP30 protein complex containing TIP30, acyl-CoA synthetase long-chain family member 4 (ACSL4) and Endophilin B1 (Endo B1) that promotes the fusion of endocytic vesicles with Rab5a vesicles, which transport endosomal acidification enzymes vacuolar (H+)-ATPases (V-ATPases) to the early endosomes in vivo. Here, we demonstrate that the TIP30 protein complex facilitates the fusion of endocytic vesicles with Rab5a vesicles in vitro. Fusion of the two vesicles also depends on arachidonic acid, coenzyme A and the synthesis of arachidonyl-CoA by ACSL4. Moreover, the TIP30 complex is able to transfer arachidonyl groups onto phosphatidic acid (PA), producing a new lipid species that is capable of inducing close contact between membranes. Together, our data suggest that the TIP30 complex facilitates biological membrane fusion through modification of PA on membranes.
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Affiliation(s)
- Chengliang Zhang
- Department of Biomedical and Integrative Physiology, Michigan State University, East Lansing, Michigan, United States of America
- Genetics Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Aimin Li
- Department of Biomedical and Integrative Physiology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Shenglan Gao
- Department of Biomedical and Integrative Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Xinchun Zhang
- Genetics Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Hua Xiao
- Department of Biomedical and Integrative Physiology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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40
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Roqueta-Rivera M, Abbott TL, Sivaguru M, Hess RA, Nakamura MT. Deficiency in the omega-3 fatty acid pathway results in failure of acrosome biogenesis in mice. Biol Reprod 2011; 85:721-32. [PMID: 21653892 DOI: 10.1095/biolreprod.110.089524] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
An omega-3 fatty acid, docosahexaenoic acid (DHA), is enriched in testicular membrane phospholipids, but its function is not well understood. The Fads2 gene encodes an enzyme required for the endogenous synthesis of DHA. Using Fads2-null mice (Fads2-/-), we found in our preceding studies that DHA deficiency caused the arrest of spermiogenesis and male infertility, both of which were reversed by dietary DHA. In this study, we investigated a cellular mechanism underlying the DHA essentiality in spermiogenesis. Periodic acid-Schiff staining and acrosin immunohistochemistry revealed the absence of acrosomes in Fads2-/- round spermatids. Acrosin, an acrosomal marker, was scattered throughout the cytoplasm of the Fads2-/- spermatids, and electron microscopy showed that proacrosomal granules were formed on the trans-face of the Golgi. However, excessive endoplasmic reticulum and vesicles were present on the cis-face of the Golgi in Fads2-/- spermatids. The presence of proacrosomal vesicles but lack of a developed acrosome in Fads2-/- spermatids suggested failed vesicle fusion. Syntaxin 2, a protein involved in vesicle fusion, colocalized with acrosin in the acrosome of wild-type mice. In contrast, syntaxin 2 remained scattered in reticular structures and showed no extensive colocalization with acrosin in the Fads2-/- spermatids, suggesting failed fusion with acrosin-containing vesicles or failed transport and release of syntaxin 2 vesicles from Golgi. Dietary supplementation of DHA in Fads2-/- mice restored an intact acrosome. In conclusion, acrosome biogenesis under DHA deficiency is halted after release of proacrosomal granules. Misplaced syntaxin 2 suggests an essential role of DHA in proper delivery of membrane proteins required for proacrosomal vesicle fusion.
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Affiliation(s)
- Manuel Roqueta-Rivera
- Department of Food Science & Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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41
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Munc18-1 and Syntaxin1: Unraveling the Interactions Between the Dynamic Duo. Cell Mol Neurobiol 2010; 30:1309-13. [DOI: 10.1007/s10571-010-9581-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/02/2010] [Indexed: 12/29/2022]
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42
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Davletov B, Montecucco C. Lipid function at synapses. Curr Opin Neurobiol 2010; 20:543-9. [DOI: 10.1016/j.conb.2010.06.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 05/27/2010] [Accepted: 06/26/2010] [Indexed: 11/25/2022]
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43
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Enrich C, Rentero C, de Muga SV, Reverter M, Mulay V, Wood P, Koese M, Grewal T. Annexin A6-Linking Ca(2+) signaling with cholesterol transport. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:935-47. [PMID: 20888375 DOI: 10.1016/j.bbamcr.2010.09.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 11/17/2022]
Abstract
Annexin A6 (AnxA6) belongs to a conserved family of Ca(2+)-dependent membrane-binding proteins. Like other annexins, the function of AnxA6 is linked to its ability to bind phospholipids in cellular membranes in a dynamic and reversible fashion, in particular during the regulation of endocytic and exocytic pathways. High amounts of AnxA6 sequester cholesterol in late endosomes, thereby lowering the levels of cholesterol in the Golgi and the plasma membrane. These AnxA6-dependent redistributions of cellular cholesterol pools give rise to reduced cytoplasmic phospholipase A2 (cPLA(2)) activity, retention of caveolin in the Golgi apparatus and a reduced number of caveolae at the cell surface. In addition to regulating cholesterol and caveolin distribution, AnxA6 acts as a scaffold/targeting protein for several signaling proteins, the best characterized being the Ca(2+)-dependent membrane targeting of p120GAP to downregulate Ras activity. AnxA6 also stimulates the Ca(2+)-inducible involvement of PKC in the regulation of HRas and possibly EGFR signal transduction pathways. The ability of AnxA6 to recruit regulators of the EGFR/Ras pathway is likely potentiated by AnxA6-induced actin remodeling. Accordingly, AnxA6 may function as an organizer of membrane domains (i) to modulate intracellular cholesterol homeostasis, (ii) to create a scaffold for the formation of multifactorial signaling complexes, and (iii) to regulate transient membrane-actin interactions during endocytic and exocytic transport. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
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44
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Rituper B, Davletov B, Zorec R. Lipid–protein interactions in exocytotic release of hormones and neurotransmitters. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/clp.10.61] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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45
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Smyth AM, Rickman C, Duncan RR. Vesicle fusion probability is determined by the specific interactions of munc18. J Biol Chem 2010; 285:38141-8. [PMID: 20801887 PMCID: PMC2992247 DOI: 10.1074/jbc.m110.164038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian-regulated secretion is absolutely dependent on four evolutionarily conserved proteins: three SNARE proteins and munc18. Dissecting the functional outcomes of the spatially organized protein interactions between these factors has been difficult because of the close interrelationship between different binding modes. Here, we investigated the spatial distribution of single munc18 molecules at the plasma membrane of cells and the underlying interactions between syntaxin and munc18. Disruption of munc18 binding to the N-terminal peptide motif of syntaxin did not alter munc18 localization on the plasma membrane but had a pronounced influence on the behavior of secretory vesicles and their likelihood to undergo fusion. We therefore conclude that interaction with the syntaxin N-peptide can confer differential release probabilities to secretory vesicles and may contribute to the delineation of secretory vesicle pools.
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Affiliation(s)
- Annya M Smyth
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, United Kingdom
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46
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Löhmann C, Schachmann E, Dandekar T, Villmann C, Becker CM. Developmental profiling by mass spectrometry of phosphocholine containing phospholipids in the rat nervous system reveals temporo-spatial gradients. J Neurochem 2010; 114:1119-34. [PMID: 20524967 DOI: 10.1111/j.1471-4159.2010.06836.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Phospholipids are important components of the nervous system, in particular of neuronal and glial membranes. Ontogenesis of the nervous system is associated with fundamental alterations in lipid patterns. Here, matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry and electro-spray-ionization mass spectrometry were combined to analyze phosphatidylcholines and sphingomyelins, allowing an assessment of individual molecular species. Analysis in eight different regions of the nervous system during development of the Wistar rat, from embryonic day 14 to adulthood, produced informative patterns of developmental and regional changes in lipid contents. Phospholipids containing long chain fatty acyl residues exhibited a characteristic patterning, with dramatic increases in the caudal parts of the nervous system 2 weeks after birth. In contrast, relative contents of short chain phosphatidylcholines were low in the perinatal CNS, decreasing even further during development. The relative amounts of sphingomyelins carrying the fatty acid residues 18:0, 22:0, 24:0, and 24:1 increased developmentally in the caudal nervous system. The rostro-caudal gradient of long chain lipid accumulation is matched by expression gradients of myelin structural and regulatory genes, as evident from bioinformatic analysis. These observations characterize the accumulation of individual lipid classes in the nervous system as a highly regulated process, with structurally related lipids showing a similar temporo-spatial distribution and developmental patterning.
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Affiliation(s)
- Christian Löhmann
- Emil-Fischer-Zentrum, Institut für Biochemie, Universität Erlangen-Nürnberg, Erlangen, Germany
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47
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Alpha-synuclein sequesters arachidonic acid to modulate SNARE-mediated exocytosis. EMBO Rep 2010; 11:528-33. [PMID: 20489724 DOI: 10.1038/embor.2010.66] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 03/22/2010] [Accepted: 04/14/2010] [Indexed: 01/06/2023] Open
Abstract
Alpha-synuclein is a synaptic modulatory protein implicated in the pathogenesis of Parkinson disease. The precise functions of this small cytosolic protein are still under investigation. alpha-Synuclein has been proposed to regulate soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins involved in vesicle fusion. Interestingly, alpha-synuclein fails to interact with SNARE proteins in conventional protein-binding assays, thus suggesting an indirect mode of action. As the structural and functional properties of both alpha-synuclein and the SNARE proteins can be modified by arachidonic acid, a common lipid regulator, we analysed this possible tripartite link in detail. Here, we show that the ability of arachidonic acid to stimulate SNARE complex formation and exocytosis can be controlled by alpha-synuclein, both in vitro and in vivo. Alpha-synuclein sequesters arachidonic acid and thereby blocks the activation of SNAREs. Our data provide mechanistic insights into the action of alpha-synuclein in the modulation of neurotransmission.
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48
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Castillo MA, Ghose S, Tamminga CA, Ulery-Reynolds PG. Deficits in syntaxin 1 phosphorylation in schizophrenia prefrontal cortex. Biol Psychiatry 2010; 67:208-16. [PMID: 19748077 DOI: 10.1016/j.biopsych.2009.07.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Schizophrenia has been described as a disease of the synapse. On the basis of previous studies reporting reductions in the levels and activity of CK2 (also know as casein kinase 2 or II) in the brain of subjects with schizophrenia, we hypothesized that CK2-mediated phosphorylation of the presynaptic protein syntaxin 1 (Stx 1) is deficient in schizophrenia. This in turn could affect the binding of Stx 1 to its protein partners and result in abnormal neurotransmitter release and synaptic transmission. METHODS We analyzed post mortem prefrontal cortex samples from 15 schizophrenia cases and matched controls by quantitative immunoblotting. RESULTS In addition to replicating previous findings of reduced CK2 levels, we show that as predicted, the deficit in CK2 correlates with a deficit in phospho-Stx 1. In contrast, we find that these deficits are not present in depression cases. Further, we show that the reduced levels of CK2 and phospho-Stx 1 are not due to treatment with antipsychotic drugs (APDs). In fact, APDs seem to increase both CK2 and phospho-Stx 1, suggesting that their therapeutic action may be associated with the reversal of these deficits. Finally, we show that lower phospho-Stx 1 levels are associated with reduced binding of Stx 1 to SNAP-25 and MUNC18 and decreased SNARE complex formation. CONCLUSIONS Our findings constitute the first report of altered phosphorylation of a key component for neurotransmitter release in humans and suggest that regulation of Stx 1 by CK2-mediated phosphorylation could play a role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Max A Castillo
- Department of Neurology, The University of Texas, Southwestern Medical Center, Dallas, Texas, USA
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49
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Rickman C, Duncan RR. Munc18/Syntaxin interaction kinetics control secretory vesicle dynamics. J Biol Chem 2009; 285:3965-3972. [PMID: 19748891 PMCID: PMC2823538 DOI: 10.1074/jbc.m109.040402] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In neuronal and hormonal release, regulated exocytosis requires an essential set of proteins: the soluble N-ethylmaleimide sensitive-factor attachment receptor proteins (SNAREs) syntaxin 1, SNAP-25, VAMP, and their regulator, Munc18. Recently, it was found that Munc18-1 can interact with syntaxin 1 through distinct mechanisms: an inhibitory mode enveloping syntaxin (mode 1), sequestering it from SNARE protein interactions, and direct binding to an evolutionarily conserved N-terminal peptide of syntaxin (mode 2/3). The latter interaction has been proposed to control "priming" of the fusion reaction, defined using electrophysiology, but it is unknown how this interaction is regulated, and any dynamic effect at the molecular or vesicular level in cells remains undiscovered. We now show that a phosphorylation site in syntaxin 1 (Ser(14)) regulates the N-terminal interaction with Munc18-1. Probing syntaxin 1 association with Munc18-1, in real-time and in living cells, we found that modification of Ser(14) modulated the dynamics of this interaction, specifically at the plasma membrane. Destabilization of this dynamic interaction enhanced vesicle immobilization at the plasma membrane with a resulting inhibition of exocytosis.
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Affiliation(s)
- Colin Rickman
- From the Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, Scotland, United Kingdom
| | - Rory R Duncan
- From the Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, Scotland, United Kingdom.
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50
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Synaptic vesicle docking: sphingosine regulates syntaxin1 interaction with Munc18. PLoS One 2009; 4:e5310. [PMID: 19390577 PMCID: PMC2668795 DOI: 10.1371/journal.pone.0005310] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 03/12/2009] [Indexed: 01/10/2023] Open
Abstract
Consensus exists that lipids must play key functions in synaptic activity but precise mechanistic information is limited. Acid sphingomyelinase knockout mice (ASMko) are a suitable model to address the role of sphingolipids in synaptic regulation as they recapitulate a mental retardation syndrome, Niemann Pick disease type A (NPA), and their neurons have altered levels of sphingomyelin (SM) and its derivatives. Electrophysiological recordings showed that ASMko hippocampi have increased paired-pulse facilitation and post-tetanic potentiation. Consistently, electron microscopy revealed reduced number of docked vesicles. Biochemical analysis of ASMko synaptic membranes unveiled higher amounts of SM and sphingosine (Se) and enhanced interaction of the docking molecules Munc18 and syntaxin1. In vitro reconstitution assays demonstrated that Se changes syntaxin1 conformation enhancing its interaction with Munc18. Moreover, Se reduces vesicle docking in primary neurons and increases paired-pulse facilitation when added to wt hippocampal slices. These data provide with a novel mechanism for synaptic vesicle control by sphingolipids and could explain cognitive deficits of NPA patients.
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