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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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2
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Guo Z, Jiang CH, Tong C, Yang Y, Wang Z, Lam SM, Wang D, Li R, Shui G, Shi YS, Liu JJ. Activity-dependent PI4P synthesis by PI4KIIIα regulates long-term synaptic potentiation. Cell Rep 2022; 38:110452. [PMID: 35235793 DOI: 10.1016/j.celrep.2022.110452] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/30/2021] [Accepted: 02/07/2022] [Indexed: 01/11/2023] Open
Abstract
Phosphatidylinositol 4-phosphate (PI4P) is a low abundant phospholipid with important roles in lipid transport and membrane trafficking. However, little is known of its metabolism and function in neurons. Here, we investigate its subcellular distribution and functional roles in dendrites of rodent hippocampal neurons during resting state and long-term synaptic potentiation (LTP). We show that neural activity causes dynamic reversible changes in PI4P metabolism in dendrites. Upon LTP induction, PI4KIIIα, a type III phosphatidylinositol 4-kinase, localizes to the dendritic plasma membrane (PM) in a calcium-dependent manner and causes substantial increase in the levels of PI4P. Acute inhibition of PI4KIIIα activity abolishes trafficking of the AMPA-type glutamate receptor to the PM during LTP induction, and silencing of PI4KIIIα expression in the hippocampal CA1 region causes severe impairment of LTP and long-term memory. Collectively, our results identify an essential role for PI4KIIIα-dependent PI4P synthesis in synaptic plasticity of central nervous system neurons.
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Affiliation(s)
- Zhenzhen Guo
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Chao-Hua Jiang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Chunfang Tong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanrui Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Zehua Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Dou Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Stone Shi
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.
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3
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Altered conformation of α-synuclein drives dysfunction of synaptic vesicles in a synaptosomal model of Parkinson's disease. Cell Rep 2021; 36:109333. [PMID: 34233191 PMCID: PMC8552450 DOI: 10.1016/j.celrep.2021.109333] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/30/2020] [Accepted: 06/10/2021] [Indexed: 11/23/2022] Open
Abstract
While misfolding of alpha-synuclein (αSyn) is central to the pathogenesis of Parkinson's disease (PD), fundamental questions about its structure and function at the synapse remain unanswered. We examine synaptosomes from non-transgenic and transgenic mice expressing wild-type human αSyn, the E46K fPD-causing mutation, or an amplified form of E46K ("3K"). Synaptosomes from mice expressing the 3K mutant show reduced Ca2+-dependent vesicle exocytosis, altered synaptic vesicle ultrastructure, decreased SNARE complexes, and abnormal levels of certain synaptic proteins. With our intra-synaptosomal nuclear magnetic resonance (NMR) method, we reveal that WT αSyn participates in heterogeneous interactions with synaptic components dependent on endogenous αSyn and synaptosomal integrity. The 3K mutation markedly alters these interactions. The synaptic microenvironment is necessary for αSyn to reach its native conformations and establish a physiological interaction network. Its inability to populate diverse conformational ensembles likely represents an early step in αSyn dysfunction that contributes to the synaptotoxicity observed in synucleinopathies.
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Binotti B, Jahn R, Pérez-Lara Á. An overview of the synaptic vesicle lipid composition. Arch Biochem Biophys 2021; 709:108966. [PMID: 34139199 DOI: 10.1016/j.abb.2021.108966] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/10/2021] [Accepted: 06/10/2021] [Indexed: 11/29/2022]
Abstract
Chemical neurotransmission is the major mechanism of neuronal communication. Neurotransmitters are released from secretory organelles, the synaptic vesicles (SVs) via exocytosis into the synaptic cleft. Fusion of SVs with the presynaptic plasma membrane is balanced by endocytosis, thus maintaining the presynaptic membrane at steady-state levels. The protein machineries responsible for exo- and endocytosis have been extensively investigated. In contrast, less is known about the role of lipids in synaptic transmission and how the lipid composition of SVs is affected by dynamic exo-endocytotic cycling. Here we summarize the current knowledge about the composition, organization, and function of SV membrane lipids. We also cover lipid biogenesis and maintenance during the synaptic vesicle cycle.
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Affiliation(s)
- Beyenech Binotti
- Department of Biochemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.
| | - Ángel Pérez-Lara
- Department of Physical Chemistry, University of Granada, Campus Universitario de Cartuja, 18071, Granada, Spain.
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Cantarutti KC, Burgess J, Brill JA, Dason JS. Type II phosphatidylinositol 4-kinase regulates nerve terminal growth and synaptic vesicle recycling. J Neurogenet 2018; 32:230-235. [DOI: 10.1080/01677063.2018.1502762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - Jason Burgess
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Julie A. Brill
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Jeffrey S. Dason
- Department of Biological Sciences, University of Windsor, Windsor, Canada
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Falcone JA, Salameh TS, Yi X, Cordy BJ, Mortell WG, Kabanov AV, Banks WA. Intranasal administration as a route for drug delivery to the brain: evidence for a unique pathway for albumin. J Pharmacol Exp Ther 2014; 351:54-60. [PMID: 25027317 DOI: 10.1124/jpet.114.216705] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A variety of compounds will distribute into the brain when placed at the cribriform plate by intranasal (i.n.) administration. In this study, we investigated the ability of albumin, a protein that can act as a drug carrier but is excluded from brain by the blood-brain barrier, to distribute into the brain after i.n. administration. We labeled bovine serum albumin with [(125)I] ([(125)I]Alb) and studied its uptake into 11 brain regions and its entry into the blood from 5 minutes to 6 hours after i.n. administration. [(125)I]Alb was present throughout the brain at 5 minutes. Several regions showed distinct peaks in uptake that ranged from 5 minutes (parietal cortex) to 60 minutes (midbrain). About 2-4% of the i.n. [(125)I]Alb entered the bloodstream. The highest levels occurred in the olfactory bulb and striatum. Distribution was dose-dependent, with less taken up by whole brain, cortex, and blood at the higher dose of albumin. Uptake was selectively increased into the olfactory bulb and cortex by the fluid-phase stimulator PMA (phorbol 12-myristate 13-acetate), but inhibitors to receptor-mediated transcytosis, caveolae, and phosphoinositide 3-kinase were without effect. Albumin altered the distribution of radioactive leptin given by i.n. administration, decreasing uptake into the blood and by the cerebellum and increasing uptake by the hypothalamus. We conclude that [(125)I]Alb administered i.n. reaches all parts of the brain through a dose-dependent mechanism that may involve fluid-phase transcytosis and, as illustrated by leptin, can affect the delivery of other substances to the brain after their i.n. administration.
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Affiliation(s)
- Joseph A Falcone
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Therese S Salameh
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Xiang Yi
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Benjamin J Cordy
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - William G Mortell
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - Alexander V Kabanov
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
| | - William A Banks
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine (J.A.F., T.S.S., W.A.B.) and Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington (J.A.F., T.S.S., X.Y., B.J.C., W.G.M., W.A.B.); Center for Nanotechnology in Drug Delivery and Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina (X.Y., A.V.K.); and Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia (A.V.K.)
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7
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Dason JS, Smith AJ, Marin L, Charlton MP. Cholesterol and F-actin are required for clustering of recycling synaptic vesicle proteins in the presynaptic plasma membrane. J Physiol 2013; 592:621-33. [PMID: 24297851 DOI: 10.1113/jphysiol.2013.265447] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Synaptic vesicles (SVs) and their proteins must be recycled for sustained synaptic transmission. We tested the hypothesis that SV cholesterol is required for proper sorting of SV proteins during recycling in live presynaptic terminals. We used the reversible block of endocytosis in the Drosophila temperature-sensitive dynamin mutant shibire-ts1 to trap exocytosed SV proteins, and then examined the effect of experimental treatments on the distribution of these proteins within the presynaptic plasma membrane by confocal microscopy. SV proteins synaptotagmin, vglut and csp were clustered following SV trapping in control experiments but dispersed in samples treated with the cholesterol chelator methyl-β-cyclodextrin to extract SV cholesterol. There was accumulation of phosphatidylinositol (4,5)-bisphosphate (PIP2) in presynaptic terminals following SV trapping and this was reduced following SV cholesterol extraction. Reduced PIP2 accumulation was associated with disrupted accumulation of actin in presynaptic terminals. Similar to vesicular cholesterol extraction, disruption of actin by latrunculin A after SV proteins had been trapped on the plasma membrane resulted in the dispersal of SV proteins and prevented recovery of synaptic transmission due to impaired endocytosis following relief of the endocytic block. Our results demonstrate that vesicular cholesterol is required for aggregation of exocytosed SV proteins in the presynaptic plasma membrane and are consistent with a mechanism involving regulation of PIP2 accumulation and local actin polymerization by cholesterol. Thus, alteration of membrane or SV lipids may affect the ability of synapses to undergo sustained synaptic transmission by compromising the recycling of SV proteins.
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Affiliation(s)
- Jeffrey S Dason
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8.
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Schreiner MJ, Lazaro MT, Jalbrzikowski M, Bearden CE. Converging levels of analysis on a genomic hotspot for psychosis: insights from 22q11.2 deletion syndrome. Neuropharmacology 2013; 68:157-73. [PMID: 23098994 PMCID: PMC3677073 DOI: 10.1016/j.neuropharm.2012.09.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 09/04/2012] [Accepted: 09/17/2012] [Indexed: 10/27/2022]
Abstract
Schizophrenia is a devastating neurodevelopmental disorder that, despite extensive research, still poses a considerable challenge to attempts to unravel its heterogeneity, and the complex biochemical mechanisms by which it arises. While the majority of cases are of unknown etiology, accumulating evidence suggests that rare genetic mutations, such as 22q11.2 Deletion Syndrome (22qDS), can play a significant role in predisposition to the illness. Up to 25% of individuals with 22qDS eventually develop schizophrenia; conversely, this deletion is estimated to account for 1-2% of schizophrenia cases overall. This locus of Chromosome 22q11.2 contains genes that encode for proteins and enzymes involved in regulating neurotransmission, neuronal development, myelination, microRNA processing, and post-translational protein modifications. As a consequence of the deletion, affected individuals exhibit cognitive dysfunction, structural and functional brain abnormalities, and neurodevelopmental anomalies that parallel many of the phenotypic characteristics of schizophrenia. As an illustration of the value of rare, highly penetrant genetic subtypes for elucidating pathological mechanisms of complex neuropsychiatric disorders, we provide here an overview of the cellular, network, and systems-level anomalies found in 22qDS, and review the intriguing evidence for this disorder's association with schizophrenia. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Matthew J. Schreiner
- Interdepartmental Neuroscience Program, University of California, Los Angeles, USA
| | - Maria T. Lazaro
- Interdepartmental Neuroscience Program, University of California, Los Angeles, USA
| | | | - Carrie E. Bearden
- Department of Psychology, University of California, Los Angeles, USA
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, USA
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Abstract
Synaptic transmission is amongst the most sophisticated and tightly controlled biological phenomena in higher eukaryotes. In the past few decades, tremendous progress has been made in our understanding of the molecular mechanisms underlying multiple facets of neurotransmission, both pre- and postsynaptically. Brought under the spotlight by pioneer studies in the areas of secretion and signal transduction, phosphoinositides and their metabolizing enzymes have been increasingly recognized as key protagonists in fundamental aspects of neurotransmission. Not surprisingly, dysregulation of phosphoinositide metabolism has also been implicated in synaptic malfunction associated with a variety of brain disorders. In the present chapter, we summarize current knowledge on the role of phosphoinositides at the neuronal synapse and highlight some of the outstanding questions in this research field.
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Affiliation(s)
- Samuel G Frere
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, P&S 12-420C, 10032, New York, USA
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10
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Santiago-Tirado FH, Bretscher A. Membrane-trafficking sorting hubs: cooperation between PI4P and small GTPases at the trans-Golgi network. Trends Cell Biol 2011; 21:515-25. [PMID: 21764313 DOI: 10.1016/j.tcb.2011.05.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/24/2011] [Accepted: 05/26/2011] [Indexed: 10/18/2022]
Abstract
Cell polarity in eukaryotes requires constant sorting, packaging and transport of membrane-bound cargo within the cell. These processes occur in two sorting hubs: the recycling endosome for incoming material and the trans-Golgi network for outgoing material. Phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate are enriched at the endocytic and exocytic sorting hubs, respectively, where they act together with small GTPases to recruit factors to segregate cargo and regulate carrier formation and transport. In this review, we summarize the current understanding of how these lipids and GTPases regulate membrane trafficking directly, emphasizing the recent discoveries of phosphatidylinositol 4-phosphate functions at the trans-Golgi network.
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Affiliation(s)
- Felipe H Santiago-Tirado
- Department of Molecular Biology and Genetics, 107 Biotechnology Bldg., Cornell University, Ithaca, NY 14853-7202, USA
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Lee JS, Kim IS, Kim JH, Cho W, Suh PG, Ryu SH. Determination of EGFR endocytosis kinetic by auto-regulatory association of PLD1 with mu2. PLoS One 2009; 4:e7090. [PMID: 19763255 PMCID: PMC2739277 DOI: 10.1371/journal.pone.0007090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 08/18/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Upon ligand binding, cell surface signaling receptors are internalized through a process tightly regulated by endocytic proteins and adaptor protein 2 (AP2) to orchestrate them. Although the molecular identities and roles of endocytic proteins are becoming clearer, it is still unclear what determines the receptor endocytosis kinetics which is mainly regulated by the accumulation of endocytic apparatus to the activated receptors. METHODOLOGY/PRINCIPAL FINDINGS Here we employed the kinetic analysis of endocytosis and adaptor recruitment to show that mu2, a subunit of AP2 interacts directly with phospholipase D (PLD)1, a receptor-associated signaling protein and this facilitates the membrane recruitment of AP2 and the endocytosis of epidermal growth factor receptor (EGFR). We also demonstrate that the PLD1-mu2 interaction requires the binding of PLD1 with phosphatidic acid, its own product. CONCLUSIONS/SIGNIFICANCE These results suggest that the temporal regulation of EGFR endocytosis is achieved by auto-regulatory PLD1 which senses the receptor activation and triggers the translocation of AP2 near to the activated receptor.
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Affiliation(s)
- Jun Sung Lee
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Il Shin Kim
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Jung Hwan Kim
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Wonhwa Cho
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Pann-Ghill Suh
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
| | - Sung Ho Ryu
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, Republic of Korea
- * E-mail:
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Immunocytochemical techniques reveal multiple, distinct cellular pools of PtdIns4P and PtdIns(4,5)P(2). Biochem J 2009; 422:23-35. [PMID: 19508231 PMCID: PMC2722159 DOI: 10.1042/bj20090428] [Citation(s) in RCA: 404] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
PtdIns4P is the major precursor for the synthesis of the multifunctional plasma membrane lipid, PtdIns(4,5)P2. Yet PtdIns4P also functions as a regulatory lipid in its own right, particularly at the Golgi apparatus. In the present study we define specific conditions that enable preservation of several organellar membranes for the immunocytochemical detection of PtdIns4P. We report distinct pools of this lipid in both Golgi and plasma membranes, which are synthesized by different PI4K (phosphatidylinositol 4-kinase) activities, and also the presence of PtdIns4P in cytoplasmic vesicles, which are not readily identifiable as PI4K containing trafficking intermediates. In addition, we present evidence that the majority of PtdIns4P resides in the plasma membrane, where it is metabolically distinct from the steady-state plasma membrane pool of PtdIns(4,5)P2.
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13
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Loss of phosphatidylinositol 4-kinase 2alpha activity causes late onset degeneration of spinal cord axons. Proc Natl Acad Sci U S A 2009; 106:11535-9. [PMID: 19581584 DOI: 10.1073/pnas.0903011106] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphoinositide (PI) lipids are intracellular membrane signaling intermediates and effectors produced by localized PI kinase and phosphatase activities. Although many signaling roles of PI kinases have been identified in cultured cell lines, transgenic animal studies have produced unexpected insight into the in vivo functions of specific PI 3- and 5-kinases, but no mammalian PI 4-kinase (PI4K) knockout has previously been reported. Prior studies using cultured cells implicated the PI4K2alpha isozyme in diverse functions, including receptor signaling, ion channel regulation, endosomal trafficking, and regulated secretion. We now show that despite these important functions, mice lacking PI4K2alpha kinase activity initially appear normal. However, adult Pi4k2a(GT/GT) animals develop a progressive neurological disease characterized by tremor, limb weakness, urinary incontinence, and premature mortality. Histological analysis of aged Pi4k2a(GT/GT) animals revealed lipofuscin-like deposition and gliosis in the cerebellum, and loss of Purkinje cells. Peripheral nerves are essentially normal, but massive axonal degeneration was found in the spinal cord in both ascending and descending tracts. These results reveal a previously undescribed role for aberrant PI signaling in neurological disease that resembles autosomal recessive hereditary spastic paraplegia.
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Villasuso AL, Racagni GE, Machado EE. Phosphatidylinositol kinases as regulators of GA-stimulated alpha-amylase secretion in barley (Hordeum vulgare). PHYSIOLOGIA PLANTARUM 2008; 133:157-166. [PMID: 18282190 DOI: 10.1111/j.1399-3054.2008.01050.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Phosphorylated derivatives of phosphatidylinositol, in association with phosphatidylinositol 3-kinase (PI3 kinase, EC 2.7.1.137) and phosphatidylinositol 4-kinase (PI4 kinase, EC 2.7.1.67), play a key role in regulation of fundamental cell processes. We present evidence for a relationship between alpha-amylase (EC 3.2.1.1) secretion regulated by GA and levels of phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate (PtdIns(4)P) in barley (Hordeum vulgare). Microsomal membranes were incubated in the presence of [gamma-(32)P]ATP, and radiolabeled membrane lipids were extracted and separated by TLC using a boric acid system. Treatment of aleurone layers with GA for short or long periods of time increased PI4 kinase activity. To evaluate the effect of PtdIns(4)P levels on GA signaling, we used phenylarsine oxide (PAO), an inhibitor of PI4 kinase activity. PAO reversibly reduced the alpha-amylase secretion and protoplast cell vacuolation in a dose-dependent manner. Wortmannin showed a similar inhibitory effect on alpha-amylase secretion and PI4 kinase activity. GA evoked only a long-term increase in PI3 kinase activity, which was also affected by PAO. The effect of PAO was suppressed by the reducing agent 2,3-dimercapto-1-propanol (BAL), leading to restoration of secretion, vacuolation and PI4 kinase activity. In contrast, the effect of PAO on PI3 kinase activity was not abolished by BAL, suggesting that PI3 kinase is not involved in the secretion process. Likewise, the compound LY294002 inhibited PI3 kinase but had no effect on the secretion process. These findings indicate that PI4 kinase acts as a positive regulator of early GA signaling in aleurone.
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Affiliation(s)
- Ana Laura Villasuso
- Química Biológica, FCEFQN, Universidad Nacional de Río Cuarto, X5804BYA Río Cuarto, Córdoba, Argentina
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15
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Karashima Y, Prenen J, Meseguer V, Owsianik G, Voets T, Nilius B. Modulation of the transient receptor potential channel TRPA1 by phosphatidylinositol 4,5-biphosphate manipulators. Pflugers Arch 2008; 457:77-89. [DOI: 10.1007/s00424-008-0493-6] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Accepted: 03/05/2008] [Indexed: 11/29/2022]
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16
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Abstract
G-proteins (guanine nucleotide-binding proteins) are membrane-attached proteins composed of three subunits, alpha, beta, and gamma. They transduce signals from G-protein coupled receptors (GPCRs) to target effector proteins. The agonistactivated receptor induces a conformational change in the G-protein trimer so that the alpha-subunit binds GTP in exchange for GDP and alpha-GTP, and betagamma-subunits separate to interact with the target effector. Effector-interaction is terminated by the alpha-subunit GTPase activity, whereby bound GTP is hydrolyzed to GDP. This is accelerated in situ by RGS proteins, acting as GTPase-activating proteins (GAPs). Galpha-GDP and Gbetagamma then reassociate to form the Galphabetagamma trimer. G-proteins primarily involved in the modulation of neurotransmitter release are G(o), G(q) and G(s). G(o) mediates the widespread presynaptic auto-inhibitory effect of many neurotransmitters (e.g., via M2/M4 muscarinic receptors, alpha(2) adrenoreceptors, micro/delta opioid receptors, GABAB receptors). The G(o) betagamma-subunit acts in two ways: first, and most ubiquitously, by direct binding to CaV2 Ca(2+) channels, resulting in a reduced sensitivity to membrane depolarization and reduced Ca(2+) influx during the terminal action potential; and second, through a direct inhibitory effect on the transmitter release machinery, by binding to proteins of the SNARE complex. G(s) and G(q) are mainly responsible for receptor-mediated facilitatory effects, through activation of target enzymes (adenylate cyclase, AC and phospholipase-C, PLC respectively) by the GTP-bound alpha-subunits.
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Affiliation(s)
- David A Brown
- Department of Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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17
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Hammond GRV, Schiavo G. Polyphosphoinositol lipids: Under-PPInning synaptic function in health and disease. Dev Neurobiol 2007; 67:1232-47. [PMID: 17514716 DOI: 10.1002/dneu.20509] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Phosphoinositides (PPIn) form a unique family of lipids derived by phosphorylation of the parent compound, phosphatidylinositol. Despite being minor constituents of synaptic membranes, these lipids have exceptionally high rates of metabolic turnover and are involved with myriad aspects of pre- and post-synaptic function, from the control of the synaptic vesicle cycle to postsynaptic excitability. In this review, we outline the main synaptic processes known to be regulated by these molecules, focusing mainly but not exclusively on the major species phosphatidylinositol 4-phosphate and phosphatidylinositol (4,5)-bisphosphate. Furthermore, we discuss the enzymes responsible for their synthesis and degradation, with a view to exploring how the activity-dependent control of their enzymatic action can lead to the precise regulation of PPIn levels at the nerve terminal. Also, the modulation of synaptic PPIn turnover by drugs used for the treatment of bipolar disorder is discussed. We propose that the modulation of PPIn levels may act as a central mechanism to coordinate the cascade of synaptic events leading to neurotransmission.
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Affiliation(s)
- Gerald R V Hammond
- Molecular NeuroPathobiology, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3PX, United Kingdom.
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18
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Abstract
Exocytosis of neurotransmitter containing vesicles supports neuronal communication. The importance of molecular interactions involving specific lipids has become progressively more evident and the lipid composition of both the synaptic vesicle and the pre-synaptic plasma membrane at the active zone has significant functional consequences for neurotransmitter release. Several classes of lipids have been implicated in exocytosis including polyunsaturated fatty acids and phosphoinositides. This minireview will focus on recent developments regarding the role of phosphoinositides in neurosecretion.
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Affiliation(s)
- Shona L Osborne
- Molecular Dynamics of Synaptic Function Laboratory, School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, Australia
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19
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Holz RW. Analysis of the late steps of exocytosis: biochemical and total internal reflection fluorescence microscopy (TIRFM) studies. Cell Mol Neurobiol 2006; 26:439-47. [PMID: 16625428 DOI: 10.1007/s10571-006-9049-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Accepted: 03/08/2006] [Indexed: 10/24/2022]
Abstract
1. Time with Julie in his laboratory at the NIH in the early 1970s is remembered. The experience led to a life-long interest in the regulation of catecholamine secretion. Here are summarized aspects of this work. 2. The relationship between ATP-dependent priming of exocytosis and the polyphosphoinositides is reviewed. In addition, studies are summarized in which total internal reflection fluorescent microscopy (TIRFM) was used to visualize secretory granule behavior before exocytosis and individual exocytotic events. 3. Quantitative optical analysis indicates that chromaffin granule motion is highly restricted but regulated. Granules can undergo significant motion in the 100 ms prior to fusion and interactions with the plasma membrane leading to fusion can occur within this time. The small motions may permit granules adjacent to the plasma membrane to repetitively sample microdomains of the plasma membrane, thereby increasing the probability of fruitful interactions that lead to fusion.
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Affiliation(s)
- Ronald W Holz
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0632, USA.
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20
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Meunier FA, Osborne SL, Hammond GRV, Cooke FT, Parker PJ, Domin J, Schiavo G. Phosphatidylinositol 3-kinase C2alpha is essential for ATP-dependent priming of neurosecretory granule exocytosis. Mol Biol Cell 2005; 16:4841-51. [PMID: 16055506 PMCID: PMC1237087 DOI: 10.1091/mbc.e05-02-0171] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 06/16/2005] [Accepted: 07/14/2005] [Indexed: 11/11/2022] Open
Abstract
Neurotransmitter release and hormonal secretion are highly regulated processes culminating in the calcium-dependent fusion of secretory vesicles with the plasma membrane. Here, we have identified a role for phosphatidylinositol 3-kinase C2alpha (PI3K-C2alpha) and its main catalytic product, PtdIns3P, in regulated exocytosis. In neuroendocrine cells, PI3K-C2alpha is present on a subpopulation of mature secretory granules. Impairment of PI3K-C2alpha function specifically inhibits the ATP-dependent priming phase of exocytosis. Overexpression of wild-type PI3K-C2alpha enhanced secretion, whereas transfection of PC12 cells with a catalytically inactive PI3K-C2alpha mutant or a 2xFYVE domain sequestering PtdIns3P abolished secretion. Based on these results, we propose that production of PtdIns3P by PI3K-C2alpha is required for acquisition of fusion competence in neurosecretion.
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Affiliation(s)
- Frédéric A Meunier
- Lincoln's Inn Fields Laboratories, London Research Institute, Cancer Research UK, London WC2A 3PX, United Kingdom
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21
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Lechner SG, Hussl S, Schicker KW, Drobny H, Boehm S. Presynaptic inhibition via a phospholipase C- and phosphatidylinositol bisphosphate-dependent regulation of neuronal Ca2+ channels. Mol Pharmacol 2005; 68:1387-96. [PMID: 16099842 DOI: 10.1124/mol.105.014886] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Presynaptic inhibition of transmitter release is commonly mediated by a direct interaction between G protein betagamma subunits and voltage-activated Ca2+ channels. To search for an alternative pathway, the mechanisms by which presynaptic bradykinin receptors mediate an inhibition of noradrenaline release from rat superior cervical ganglion neurons were investigated. The peptide reduced noradrenaline release triggered by K+-depolarization but not that evoked by ATP, with Ca2+ channels being blocked by Cd2+. Bradykinin also reduced Ca2+ current amplitudes measured at neuronal somata, and this effect was pertussis toxin-insensitive, voltage-independent, and developed slowly within 1 min. The inhibition of Ca2+ currents was abolished by a phospholipase C inhibitor, but it was not altered by a phospholipase A2 inhibitor, by the depletion of intracellular Ca2+ stores, or by the inactivation of protein kinase C or Rho proteins. In whole-cell recordings, the reduction of Ca2+ currents was irreversible but became reversible when 4 mM ATP or 0.2 mM dioctanoyl phosphatidylinositol-4,5-bisphosphate was included in the pipette solution. In contrast, the effect of bradykinin was entirely reversible in perforated-patch recordings but became irreversible when the resynthesis of phosphatidylinositol-4,5-bisphosphate was blocked. Thus, the inhibition of Ca2+ currents by bradykinin involved a consumption of phosphatidylinositol-4,5-bisphosphate by phospholipase C but no downstream effectors of this enzyme. The reduction of noradrenaline release by bradykinin was also abolished by the inhibition of phospholipase C or of the resynthesis of phosphatidylinositol-4,5-bisphosphate. These results show that the presynaptic inhibition was mediated by a closure of voltage-gated Ca2+ channels through depletion of membrane phosphatidylinositol bisphosphates via phospholipase C.
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Affiliation(s)
- Stefan G Lechner
- Department of Pharmacology, Center of Biomolecular, Medicine and Pharmacology, Medical University of Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
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Itakura M, Yamamori S, Kuwahara R, Sekiguchi M, Takahashi M. Two distinct regulatory mechanisms of neurotransmitter release by phosphatidylinositol 3-kinase. J Neurochem 2005; 94:502-9. [PMID: 15998300 DOI: 10.1111/j.1471-4159.2005.03242.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Recent studies have indicated that various growth factors are involved in synaptic functions; however, the precise mechanisms remain unclear. In order to elucidate the molecular mechanisms of the growth factor-mediated regulation of presynaptic functions, the effects of epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) on neurotransmitter release were studied in rat PC12 cells. Brief treatment with EGF and IGF-1 enhanced Ca2+-dependent dopamine release in a concentration-dependent manner. EGF activated both mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3-kinase) pathways, and the EGF-dependent enhancement of DA release was suppressed by a MAPK kinase inhibitor as well as by PI3-kinase inhibitors. In striking contrast, IGF-1 activated the PI3-kinase pathway but not the MAPK pathway, and IGF-1-dependent enhancement was suppressed by a PI3-kinase inhibitor but not by a MAPK kinase inhibitor. The enhanced green fluorescent protein-tagged pleckstrin homology (PH) domain of protein kinase B, which selectively binds to phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,4,5-triphosphate, was translocated to the plasma membrane after treatment with either EGF or NGF. By contrast, no significant redistribution was induced by IGF-1. These results indicate that PI3-kinase participates in the enhancement of neurotransmitter release by two distinct mechanisms: EGF and NGF activate PI3-kinase in the plasma membrane, whereas IGF-1 activates PI3-kinase possibly in the intracellular membrane, leading to enhancement of neurotransmitter release in a MAPK-dependent and -independent manner respectively.
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Di Paolo G, Moskowitz HS, Gipson K, Wenk MR, Voronov S, Obayashi M, Flavell R, Fitzsimonds RM, Ryan TA, De Camilli P. Impaired PtdIns(4,5)P2 synthesis in nerve terminals produces defects in synaptic vesicle trafficking. Nature 2004; 431:415-22. [PMID: 15386003 DOI: 10.1038/nature02896] [Citation(s) in RCA: 294] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2004] [Accepted: 07/27/2004] [Indexed: 11/08/2022]
Abstract
Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) has an important function in cell regulation both as a precursor of second messenger molecules and by means of its direct interactions with cytosolic and membrane proteins. Biochemical studies have suggested a role for PtdIns(4,5)P2 in clathrin coat dynamics, and defects in its dephosphorylation at the synapse produce an accumulation of coated endocytic intermediates. However, the involvement of PtdIns(4,5)P2 in synaptic vesicle exocytosis remains unclear. Here, we show that decreased levels of PtdIns(4,5)P2 in the brain and an impairment of its depolarization-dependent synthesis in nerve terminals lead to early postnatal lethality and synaptic defects in mice. These include decreased frequency of miniature currents, enhanced synaptic depression, a smaller readily releasable pool of vesicles, delayed endocytosis and slower recycling kinetics. Our results demonstrate a critical role for PtdIns(4,5)P2 synthesis in the regulation of multiple steps of the synaptic vesicle cycle.
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Affiliation(s)
- Gilbert Di Paolo
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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24
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Abstract
Proteins that make, consume, and bind to phosphoinositides are important for constitutive membrane traffic. Different phosphoinositides are concentrated in different parts of the central vacuolar pathway, with phosphatidylinositol 4-phosphate predominate on Golgi, phosphatidylinositol 4,5-bisphosphate predominate at the plasma membrane, phosphatidylinositol 3-phosphate the major phosphoinositide on early endosomes, and phosphatidylinositol 3,5-bisphosphate found on late endocytic organelles. This spatial segregation may be the mechanism by which the direction of membrane traffic is controlled. Phosphoinositides increase the affinity of membranes for peripheral membrane proteins that function for sorting protein cargo or for the docking and fusion of transport vesicles. This implies that constitutive membrane traffic may be regulated by the mechanisms that control the activity of the enzymes that produce and consume phosphoinositides. Although the lipid kinases and phosphatases that function in constitutive membrane traffic are beginning to be identified, their regulation is poorly understood.
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Affiliation(s)
- Michael G Roth
- Dept. of Biochemistry, Univ. of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA.
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25
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Wenk MR, De Camilli P. Protein-lipid interactions and phosphoinositide metabolism in membrane traffic: insights from vesicle recycling in nerve terminals. Proc Natl Acad Sci U S A 2004; 101:8262-9. [PMID: 15146067 PMCID: PMC420382 DOI: 10.1073/pnas.0401874101] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Great progress has been made in the elucidation of the function of proteins in membrane traffic. Less is known about the regulatory role of lipids in membrane dynamics. Studies of nerve terminals, compartments highly specialized for the recycling of synaptic vesicles, have converged with studies from other systems to reveal mechanisms in protein-lipid interactions that affect membrane shape as well as the fusion and fission of vesicles. Phosphoinositides have emerged as major regulators of the binding of cytosolic proteins to the bilayer. Phosphorylation on different positions of the inositol ring generates different isomers that are heterogeneously distributed on cell membranes and that together with membrane proteins generate a "dual keys" code for the recruitment of cytosolic proteins. This code helps controlling vectoriality of membrane transport. Powerful methods for the detection of lipids are rapidly advancing this field, thus complementing the broad range of information about biological systems that can be obtained from genomic and proteomic approaches.
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Affiliation(s)
- Markus R Wenk
- Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA
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26
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Sims C, Harvey RD. Redox modulation of basal and beta-adrenergically stimulated cardiac L-type Ca(2+) channel activity by phenylarsine oxide. Br J Pharmacol 2004; 142:797-807. [PMID: 15172960 PMCID: PMC1575054 DOI: 10.1038/sj.bjp.0705845] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. Phenylarsine oxide (PAO) is commonly used to inhibit tyrosine phosphatase activity. However, PAO can affect a variety of different processes because of its ability to promote sulfhydryl oxidation. In the present study, we investigated the effects that PAO has on basal and beta-adrenergically stimulated L-type Ca(2+) channel activity in isolated cardiac myocytes. 2. Extracellular application of PAO transiently stimulated the basal L-type Ca(2+) channel activity, whereas it irreversibly inhibited protein kinase A (PKA)-dependent regulation of channel activity by isoproterenol, forskolin and 8-CPT-cAMP (8-p-chlorophenylthioadenosine 3',5'-cyclic monophosphate). PAO also inhibited channel activity irreversibly stimulated in the presence of adenosine 5'-(3-thiotriphosphate) tetralithium salt. 3. Neither the stimulatory nor the inhibitory effects of PAO were affected by the tyrosine kinase inhibitor lavendustin A, suggesting that tyrosine phosphorylation is not involved. 4. Extracellular application of the sulfhydryl-reducing agent dithiothreitol (DTT) antagonized both the stimulatory and inhibitory effects of PAO. Yet, following intracellular dialysis with DTT, only the inhibitory effect of PAO was antagonized. 5. The inhibitory effect of PAO was mimicked by intracellular, but not extracellular application of the membrane impermeant thiol oxidant 5,5'-dithio-bis(2-nitrobenzoic acid). 6. These results suggest that the stimulatory effect of PAO results from oxidation of sulfhydryl residues at an extracellular site and the inhibitory effect is due to redox regulation of an intracellular site that affects the response of the channel to PKA-dependent phosphorylation. It is concluded that the redox state of the cell may play a critical role in modulating beta-adrenergic responsiveness of the L-type Ca(2+) channel in cardiac myocytes.
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MESH Headings
- Animals
- Arsenicals/antagonists & inhibitors
- Arsenicals/pharmacology
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/physiology
- Colforsin/pharmacology
- Cyclic AMP/analogs & derivatives
- Cyclic AMP/pharmacology
- Dithiothreitol/pharmacology
- Drug Evaluation, Preclinical/methods
- Electrophysiology
- Guinea Pigs
- Isoproterenol/pharmacology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/pathology
- Myocytes, Cardiac/physiology
- Oxidation-Reduction/drug effects
- Phosphorylation/drug effects
- Protein Tyrosine Phosphatases/antagonists & inhibitors
- Protein Tyrosine Phosphatases/drug effects
- Protein Tyrosine Phosphatases/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/drug effects
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Signal Transduction
- Thionucleotides/pharmacology
- Time Factors
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Affiliation(s)
- Carl Sims
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, U.S.A
| | - Robert D Harvey
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, U.S.A
- Author for correspondence:
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Zheng Q, McFadden SC, Bobich JA. Phosphatidylinositol 4,5-bisphosphate promotes both [3H]-noradrenaline and [14C]-glutamate exocytosis from nerve endings. Neurochem Int 2004; 44:243-50. [PMID: 14602087 DOI: 10.1016/s0197-0186(03)00149-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inhibition of phosphatidylinositol 4-phosphate (PI4P) and phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)) synthesis by phenylarsine oxide (PAO) inhibits both [3H]-noradrenaline ([3H]-NA) and [14C]-glutamate ([14C]-glu) exocytosis from streptolysin-O (SLO)-perforated synaptosomes. When PI4,5P(2) is blocked by an antibody or chelated by neomycin, neurotransmitter exocytosis again is inhibited. Also, when phosphoinositide (PI) synthesis is indirectly decreased by shunting phosphatidic acid (PA) synthesis into phosphatidylbutanol production, both [14C]-glutamate and [3H]-noradrenaline exocytosis are inhibited. All of these results indicate that PI4,5P(2) is necessary for exocytosis of both synaptic vesicles (SVs) and dense core vesicles (DCVs).
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Affiliation(s)
- Qian Zheng
- Department of Chemistry, Texas Christian University, Forth Worth, TX 76129, USA
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28
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Bai J, Tucker WC, Chapman ER. PIP2 increases the speed of response of synaptotagmin and steers its membrane-penetration activity toward the plasma membrane. Nat Struct Mol Biol 2003; 11:36-44. [PMID: 14718921 DOI: 10.1038/nsmb709] [Citation(s) in RCA: 294] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Accepted: 11/05/2003] [Indexed: 11/08/2022]
Abstract
Synaptotagmin-1 (syt), the putative Ca2+ sensor for exocytosis, is anchored to the membrane of secretory organelles. Its cytoplasmic domain is composed of two Ca2+-sensing modules, C2A and C2B. Syt binds phosphatidylinositol 4,5-bisphosphate (PIP2), a plasma membrane lipid with an essential role in exocytosis and endocytosis. We resolved two modes of PIP2 binding that are mediated by distinct surfaces on the C2B domain of syt. A novel Ca2+-independent mode of binding predisposes syt to penetrate PIP2-harboring target membranes in response to Ca2+ with submillisecond kinetics. Thus, PIP2 increases the speed of response of syt and steers its membrane-penetration activity toward the plasma membrane. We propose that syt-PIP2 interactions are involved in exocytosis by facilitating the close apposition of the vesicle and target membrane on rapid time scales in response to Ca2+.
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Affiliation(s)
- Jihong Bai
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53706, USA
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29
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Taverna E, Francolini M, Jeromin A, Hilfiker S, Roder J, Rosa P. Neuronal calcium sensor 1 and phosphatidylinositol 4-OH kinase beta interact in neuronal cells and are translocated to membranes during nucleotide-evoked exocytosis. J Cell Sci 2003; 115:3909-22. [PMID: 12244129 DOI: 10.1242/jcs.00072] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neuronal calcium sensor 1 (NCS-1) belongs to a family of EF-hand calcium-binding proteins and is mainly expressed in neurons and neuroendocrine cells, where it causes facilitation of neurotransmitter release through unknown mechanisms. The yeast homologue of NCS-1 has been demonstrated to interact with and regulate the activity of yeast phosphatidylinositol 4-OH kinase beta (PI4Kbeta). However, in neurons and neurosecretory cells NCS-1 has not unequivocally been shown to interact with PI4Kbeta. Here we have compared the subcellular distribution of NCS-1 and PI4Kbeta and investigated whether they are capable of forming complexes. In neurons, both proteins are widely distributed and are present in perikarya and, to a lesser extent, in nerve terminals. A consistent portion of NCS-1 and PIK4beta is cytosolic, whereas a portion of both proteins appears to be associated with the membranes of the endoplasmic reticulum and the Golgi complex. Very small amounts of NCS-1 and PI4Kbeta are present in synaptic vesicles. Our results further demonstrate that in neurosecretory cells, endogenous NCS-1 and PIK4beta interact to form a complex that can be immunoisolated from membrane as well as from cytosolic fractions. Moreover, both proteins can be recruited to membranes when cells are treated with nucleotide receptor agonists known to increase polyphosphoinositide turnover and concomitantly induce exocytosis of secretory vesicles. Finally, in PC12 cells overexpressing NCS-1, the amount of PI4Kbeta associated with the membranes is increased concomitantly with the increased levels of NCS-1 detected in the same membrane fractions. Together, these findings demonstrate that mammalian NCS-1 and PI4Kbeta interact under physiological conditions, which suggest a possible role for NCS-1 in the translocation of PI4Kbeta to target membranes.
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Affiliation(s)
- Elena Taverna
- CNR, Institute of Neuroscience, Cellular and Molecular Pharmacology, Center of Excellence on Neurodegenerative Diseases, Department of Medical Pharmacology, University of Milan, Via Vanvitelli 32, 20129 Milan, Italy
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30
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Linetska MV, Storchak LG, Himmelreich NH. Phenylarsine oxide inhibits alpha-latrotoxin-stimulated [3H]GABA release from rat brain synaptosomes. Neurochem Int 2003; 42:583-90. [PMID: 12590941 DOI: 10.1016/s0197-0186(02)00158-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphatidylinositol 4,5-biphosphate has been implicated in a variety of membrane-trafficking processes, including exocytosis of neurotransmitters. However, there are contradictory findings concerned ability of phenylarsine oxide (PAO), an inhibitor of phosphatidylinositol 4-kinase, to affect exocytotic release of different types of neurotransmitters. We bent our efforts to a detailed analysis of action of PAO on Ca(2+)-dependent and Ca(2+)-independent [3H]GABA release produced by exposure of rat brain synaptosomes to different concentrations of alpha-latrotoxin. We also compared PAO action on alpha-latrotoxin- and 4-aminopyridine (4-AP)-evoked [3H]GABA release. The experiments have shown that release of [3H]GABA evoked by the depolarization with 4-AP was decreased by 80% as a result of action of 3 microM PAO and the complete inhibition of release was observed with 10 microM PAO. When alpha-latrotoxin as a stimulant was applied, release of [3H]GABA was increased as toxin concentration used was elevated from 0.5 to 3.0 nM, however, concomitantly, the response of the toxin-induced [3H]GABA release to PAO became attenuated: 10 microM PAO led to almost complete inhibition of the effect of 0.5 nM alpha-latrotoxin and only partly decreased (by 40%) the response to 3.0 nM alpha-latrotoxin. To test whether the efficacy of PAO depended on the toxin-induced outflow of cytosolic [3H]GABA, synaptosomes with depleted cytosolic [3H]GABA pool were also exploited. Depletion was performed by means of heteroexchange of cytosolic [3H]GABA with nipecotic acid. The experiments have shown that treatment of loaded synaptosomes with nipecotic acid resulted in some increase of [3H]GABA release evoked by 0.5 nM alpha-latrotoxin, but in the two-fold decrease of the response to 3.0 nM alpha-latrotoxin. PAO essentially inhibited [3H]GABA release from depleted synaptosomes irrespective of alpha-latrotoxin concentration used. Therefore, the amount of [3H]GABA released from cytosolic pool determined, in considerable degree, the insensitivity of alpha-latrotoxin action to PAO. Thus, our data show that subnanomolar concentrations of alpha-latrotoxin may be used for stimulation of exocytotic release of [3H]GABA. Exposure of synaptosomes with nanomolar toxin concentrations leads not only to stimulation of exocytosis, but also to leakage of [3H]GABA from cytosolic pool. PAO potently inhibits exocytotic release of [3H]GABA and its inhibitory effectiveness is diminished as far as the outflow of [3H]GABA is elevated.
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Affiliation(s)
- M V Linetska
- Department of Neurochemistry, Palladin Institute of Biochemistry, National Academy of Science of Ukraine, Leontovich Street 9, Kiev 01601, Ukraine
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31
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Olsen HL, Hoy M, Zhang W, Bertorello AM, Bokvist K, Capito K, Efanov AM, Meister B, Thams P, Yang SN, Rorsman P, Berggren PO, Gromada J. Phosphatidylinositol 4-kinase serves as a metabolic sensor and regulates priming of secretory granules in pancreatic beta cells. Proc Natl Acad Sci U S A 2003; 100:5187-92. [PMID: 12700357 PMCID: PMC154320 DOI: 10.1073/pnas.0931282100] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2002] [Accepted: 03/05/2003] [Indexed: 11/18/2022] Open
Abstract
Insulin secretion is controlled by the beta cell's metabolic state, and the ability of the secretory granules to undergo exocytosis increases during glucose stimulation in a membrane potential-independent fashion. Here, we demonstrate that exocytosis of insulin-containing secretory granules depends on phosphatidylinositol 4-kinase (PI 4-kinase) activity and that inhibition of this enzyme suppresses glucose-stimulated insulin secretion. Intracellular application of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] stimulated exocytosis by promoting the priming of secretory granules for release and increasing the number of granules residing in a readily releasable pool. Reducing the cytoplasmic ADP concentration in a way mimicking the effects of glucose stimulation activated PI 4-kinase and increased exocytosis whereas changes of the ATP concentration in the physiological range had little effect. The PI(4,5)P(2)-binding protein Ca(2+)-dependent activator protein for secretion (CAPS) is present in beta cells, and neutralization of the protein abolished both Ca(2+)- and PI(4,5)P(2)-induced exocytosis. We conclude that ADP-induced changes in PI 4-kinase activity, via generation of PI(4,5)P(2), represents a metabolic sensor in the beta cell by virtue of its capacity to regulate the release competence of the secretory granules.
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Affiliation(s)
- Hervør L Olsen
- Islet Cell Physiology, Novo Nordisk AS, Novo Alle, DK-2880 Bagsvaerd, Denmark
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32
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Guo J, Wenk MR, Pellegrini L, Onofri F, Benfenati F, De Camilli P. Phosphatidylinositol 4-kinase type IIalpha is responsible for the phosphatidylinositol 4-kinase activity associated with synaptic vesicles. Proc Natl Acad Sci U S A 2003; 100:3995-4000. [PMID: 12646710 PMCID: PMC153036 DOI: 10.1073/pnas.0230488100] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2003] [Indexed: 11/18/2022] Open
Abstract
Phosphorylation of inositol phospholipids plays a key role in cellular regulation via the generation of intracellular second messengers. In addition, it represents a mechanism to regulate interactions of the lipid bilayer with proteins and protein scaffolds involved in vesicle budding, cytoskeletal organization, and signaling. Generation of phosphatidylinositol 4-phosphate [PI(4)P] from phosphatidylinositol (PI) is an important step in this metabolic pathway because PI(4)P is a precursor of other important phosphoinositides and has protein binding properties of its own. We report here that a PI 4-kinase (PI4K) activity previously reported on synaptic vesicles is accounted for by the alpha isoform of the recently characterized type II PI4K (PI4KII) family. PI4KIIalpha, which also accounts for the bulk of PI4K activity in brain extracts, is concentrated at synapses and in the region of the Golgi complex in neuronal perikarya. Our results provide new evidence for the occurrence of a cycle of phosphoinositide synthesis and hydrolysis nested within the exo-endocytic cycle of synaptic vesicles and point to PI4KIIalpha as a critical player in this cycle.
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Affiliation(s)
- Jun Guo
- Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06510, USA
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33
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Abstract
The chemical synapse is a specialized intercellular junction that operates nearly autonomously to allow rapid, specific, and local communication between neurons. Focusing our attention on the presynaptic terminal, we review the current understanding of how synaptic morphology is maintained and then the mechanisms in synaptic vesicle exocytosis and recycling.
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Affiliation(s)
- Venkatesh N Murthy
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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34
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Rajebhosale M, Greenwood S, Vidugiriene J, Jeromin A, Hilfiker S. Phosphatidylinositol 4-OH kinase is a downstream target of neuronal calcium sensor-1 in enhancing exocytosis in neuroendocrine cells. J Biol Chem 2003; 278:6075-84. [PMID: 12471042 DOI: 10.1074/jbc.m204702200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal calcium sensor-1 (NCS-1), the mammalian orthologue of frequenin, belongs to a family of EF-hand-containing Ca(2+) sensors. NCS-1/frequenin has been shown to enhance synaptic transmission in PC12 cells and Drosophila and Xenopus, respectively. However, the precise molecular mechanism for the enhancement of exocytosis is largely unknown. In PC12 cells, NCS-1 potentiated exocytosis evoked by ATP, an agonist to phospholipase C-linked receptors, but had no effect on depolarization-evoked release. NCS-1 also enhanced exocytosis triggered by ionomycin, a Ca(2+) ionophore that bypasses K(+) and Ca(2+) channels. Overexpression of NCS-1 caused a shift in the dose-response curve of inhibition of ATP-evoked secretion using phenylarsine oxide, an inhibitor of phosphatidylinositol 4-OH kinase (PI4K). Plasma membrane phosphatidylinositol 4,5-bisphosphate pools were increased upon NCS-1 transfection as visualized using a phospholipase C-delta pleckstrin homology domain-green fluorescent protein construct. NCS-1-transfected cell extracts displayed increased phosphatidylinositol-4-phosphate biosynthesis, indicating an increase in PI4K activity. Mutations in NCS-1 equivalent to those that abolish the interaction of recoverin, another EF-hand-containing Ca(2+) sensor, with its downstream target rhodopsin kinase, lost their ability to enhance exocytosis. Taken together, the present data indicate that NCS-1 modulates the activity of PI4K, leading to increased levels of phosphoinositides and concomitant enhancement of exocytosis.
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Affiliation(s)
- Manisha Rajebhosale
- University of Manchester, School of Biological Sciences, Oxford Road, Manchester M13 9PT, United Kingdom
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35
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Saito T, Stopkova P, Diaz L, Papolos DF, Boussemart L, Lachman HM. Polymorphism screening of PIK4CA: possible candidate gene for chromosome 22q11-linked psychiatric disorders. Am J Med Genet B Neuropsychiatr Genet 2003; 116B:77-83. [PMID: 12497619 DOI: 10.1002/ajmg.b.10042] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lithium is potent non-competitive inhibitor of an enzyme involved in the metabolism of phosphatidylinositol 4,5-bisphosphate (PtdIns-4,5-P(2)), a critical phosphoinositide (PI) that regulates signal transduction and synaptic vesicle function. Interestingly, a number of genes involved in the regulation of PtdIns-4,5-P(2) synthesis and dephosphorylation are found in regions of the genome previously mapped in bipolar disorder (BPD) including 10p, 18q, 21q, and 22q. One is PIK4CA, a member of the phosphatidylinositol 4-kinase family that phosphorylates PtdIns at the D4 position of the inositol ring as part of the PtdIns-4,5-P(2) synthetic pathway. PIK4CA maps to 22q11 in a region believed to contain a susceptibility gene for psychiatric disorders. Screening of two functional domains of PIK4CA and the promoter region resulted in the identification of 15 different polymorphisms. Rare variants at a consensus splice donor site and the promoter region were found in a total of three patients with BPD, three with schizophrenia (SZ) and only one control. Several common non-synonymous changes and a common single nucleotide polymorphism (SNP) at position -31 in the putative promoter were identified and analyzed in patients with BPD, SZ, and controls. There was no difference in the allele distribution in mentally ill subjects and controls for two variants, R2259C and E2079Q, both located in the PIK4CA catalytic domain. There was, however, a trend toward significance in the distribution of the -31 promoter genotypes in bipolar subjects and controls. Although the results of this analysis were modest, considering the heterogeneity of BPD and SZ and the hypothesis that BPD may be caused by abnormalities in genes that regulate PI-mediated phenomena in the brain, the polymorphisms we detected in the PIK4CA gene should be analyzed in a larger data set to help determine their significance in 22q11-linked mental disorders.
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Affiliation(s)
- Takuya Saito
- Department of Psychiatry, Division of Psychiatry Research, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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36
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Holz RW, Axelrod D. Localization of phosphatidylinositol 4,5-P(2) important in exocytosis and a quantitative analysis of chromaffin granule motion adjacent to the plasma membrane. Ann N Y Acad Sci 2002; 971:232-43. [PMID: 12438123 DOI: 10.1111/j.1749-6632.2002.tb04467.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A slow ATP-dependent priming step precedes a rapid, Ca(2+)-dependent triggering step in exocytosis in chromaffin cells and in most, if not all, differentiated secretory cells. A major component of ATP-dependent secretion in permeabilized cells reflects the maintenance of the polyphosphoinositides, especially PtdIns-4,5-P2. Here we summarize recent experiments with PH-GFP (binds to PtdIns-4,5-P2) that indicate that PtdIns-4,5-P2 is localized primarily on the plasma membrane in chromaffin cells, and that it is this pool that plays a role in exocytosis. It is demonstrated that transiently expressed PH-GFP inhibits secretion in subsequently permeabilized cells. Recent studies using total internal reflection fluorescent microscopy (TIRFM) to measure chromaffin granule motion adjacent to the plasma membrane are also summarized. The quantitative analysis indicates that chromaffin granule motion is highly restricted and suggests that chromaffin granules are caged or tethered immediately adjacent to the plasma membrane.
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Affiliation(s)
- Ronald W Holz
- Department of Pharmacology and Department of Physics, Biophysics Research Division, University of Michigan, Ann Arbor, Michigan 48109, USA.
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37
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Scalettar BA, Rosa P, Taverna E, Francolini M, Tsuboi T, Terakawa S, Koizumi S, Roder J, Jeromin A. Neuronal calcium sensor-1 binds to regulated secretory organelles and functions in basal and stimulated exocytosis in PC12 cells. J Cell Sci 2002; 115:2399-412. [PMID: 12006624 DOI: 10.1242/jcs.115.11.2399] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neuronal calcium sensor-1 (NCS-1) and its non-mammalian homologue,frequenin, have been implicated in a spectrum of cellular processes, including regulation of stimulated exocytosis of synaptic vesicles and secretory granules (SGs) in neurons and neuroendocrine cells and regulation of phosphatidylinositol 4-kinase beta activity in yeast. However, apart from these intriguing putative functions, NCS-1 and frequenin are relatively poorly understood. Here, the distribution, dynamics and function of NCS-1 were studied using PC12 cells that stably express NCS-1-EYFP (NCS-1 fused to enhanced yellow fluorescent protein) or that stably overexpress NCS-1. Fluorescence and electron microscopies show that NCS-1-EYFP is absent from SGs but is present on small clear organelles, some of which are just below the plasma membrane. Total internal reflection fluorescence microscopy shows that NCS-1-EYFP is associated with synaptic-like microvesicles (SLMVs) in growth cones. Overexpression studies show that NCS-1 enhances exocytosis of synaptotagmin-labeled regulated secretory organelles (RSOs) under basal conditions and during stimulation by UTP. Significantly, these studies implicate NCS-1 in the enhancement of both basal and stimulated phosphoinositide-dependent exocytosis of RSOs in PC12 cells, and they show that NCS-1 is distributed strategically to interact with putative targets on the plasma membrane and on SLMVs. These studies also reveal that SLMVs undergo both fast directed motion and highly hindered diffusive motion in growth cones, suggesting that cytoskeletal constituents can both facilitate and hinder SLMV motion. These results also reveal interesting similarities and differences between transport organelles in differentiated neuroendocrine cells and neurons.
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Affiliation(s)
- Bethe A Scalettar
- Department of Physics, Lewis and Clark College, Portland, OR 97219, USA.
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38
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Ashton AC, Volynski KE, Lelianova VG, Orlova EV, Van Renterghem C, Canepari M, Seagar M, Ushkaryov YA. alpha-Latrotoxin, acting via two Ca2+-dependent pathways, triggers exocytosis of two pools of synaptic vesicles. J Biol Chem 2001; 276:44695-703. [PMID: 11572875 DOI: 10.1074/jbc.m108088200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Latrotoxin stimulates three types of [(3)H]gamma-aminobutyric acid and [(14)C]glutamate release from synaptosomes. The Ca(2+)-independent component (i) is insensitive to SNAP-25 cleavage or depletion of vesicle contents by bafilomycin A1 and represents transmitter efflux mediated by alpha-latrotoxin pores. Two other components of release are Ca(2+)-dependent and vesicular but rely on distinct mechanisms. The fast receptor-mediated pathway (ii) involves intracellular Ca(2+) stores and acts upon sucrose-sensitive readily releasable vesicles; this mechanism is insensitive to inhibition of phosphatidylinositol 4-kinase (PI 4-kinase). The delayed pore-dependent exocytotic component (iii) is stimulated by Ca(2+) entering through alpha-latrotoxin pores; it requires PI 4-kinase and occurs mainly from depot vesicles. Lanthanum perturbs alpha-latrotoxin pores and blocks the two pore-mediated components (i, iii) but not the receptor-mediated release (ii). alpha-Latrotoxin mutant (LTX(N4C)) cannot form pores and stimulates only the Ca(2+)-dependent receptor-mediated amino acid exocytosis (ii) (detectable biochemically and electrophysiologically). These findings explain experimental data obtained by different laboratories and implicate the toxin receptors in the regulation of the readily releasable pool of synaptic vesicles. Our results also suggest that, similar to noradrenergic vesicles, amino acid-containing vesicles at some point in their cycle require PI 4-kinase.
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Affiliation(s)
- A C Ashton
- Biochemistry Department, Imperial College, Exhibition Road, London SW7 2AY, United Kingdom
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39
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Wenk MR, Pellegrini L, Klenchin VA, Di Paolo G, Chang S, Daniell L, Arioka M, Martin TF, De Camilli P. PIP kinase Igamma is the major PI(4,5)P(2) synthesizing enzyme at the synapse. Neuron 2001; 32:79-88. [PMID: 11604140 DOI: 10.1016/s0896-6273(01)00456-1] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Disruption of the presynaptically enriched polyphosphoinositide phosphatase synaptojanin 1 leads to an increase of clathrin-coated intermediates and of polymerized actin at endocytic zones of nerve terminals. These changes correlate with elevated levels of PI(4,5)P(2) in neurons. We report that phosphatidylinositol phosphate kinase type Igamma (PIPKIgamma), a major brain PI(4)P 5-kinase, is concentrated at synapses. Synaptojanin 1 and PIPKIgamma antagonize each other in the recruitment of clathrin coats to lipid membranes. Like synaptojanin 1 and other proteins involved in endocytosis, PIPKIgamma undergoes stimulation-dependent dephosphorylation. These results implicate PIPKIgamma in the synthesis of a PI(4,5)P(2) pool that acts as a positive regulator of clathrin coat recruitment and actin function at the synapse.
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Affiliation(s)
- M R Wenk
- Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA
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40
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Wang CY, Yang F, He X, Chow A, Du J, Russell JT, Lu B. Ca(2+) binding protein frequenin mediates GDNF-induced potentiation of Ca(2+) channels and transmitter release. Neuron 2001; 32:99-112. [PMID: 11604142 DOI: 10.1016/s0896-6273(01)00434-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Molecular mechanisms underlying long-term neurotrophic regulation of synaptic transmission and plasticity are unknown. We report here that long-term treatment of neuromuscular synapses with glial cell line-derived neurotrophic factor (GDNF) potentiates spontaneous and evoked transmitter release, in ways very similar to presynaptic expression of the Ca(2+) binding protein frequenin. GDNF enhances the expression of frequenin in motoneurons, and inhibition of frequenin expression or activity prevents the synaptic action of GDNF. GDNF also facilitates Ca(2+) influx into the nerve terminals during evoked transmission by enhancing Ca(2+) currents. The effect of GDNF on Ca(2+) currents is blocked by inhibition of frequenin expression, occluded by overexpression of frequenin, and is selective to N-type Ca(2+) channels. These results identify an important molecular target that mediates the long-term, synaptic action of a neurotrophic factor.
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Affiliation(s)
- C Y Wang
- Laboratory of Cellular and Synaptic Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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41
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Heidelberger R. Electrophysiological approaches to the study of neuronal exocytosis and synaptic vesicle dynamics. Rev Physiol Biochem Pharmacol 2001; 143:1-80. [PMID: 11428263 DOI: 10.1007/bfb0115592] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- R Heidelberger
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, University of Texas, Houston Health Science Center, Houston, Texas 77025, USA
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42
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Abstract
Nerve terminals are highly enriched in proteins needed for endocytosis. Although constitutive and ligand-stimulated endocytosis take place in nerve terminals, the primary type is compensatory endocytosis--the process by which a cell retrieves the additional membrane added to cell surface by a regulated secretory event. This process has been extensively characterized using electrophysiological techniques. Except for an unusual form of coupled exo- and endocytosis called kiss-and-run release, compensatory endocytosis appears to use basically the same clathrin-mediated mechanisms as the constitutive and ligand stimulated type. The remarkable speed and selectivity of compensatory endocytosis may be achieved by concentrating the machinery at specialized sites in the nerve terminal adjacent to exocytosis sites and by the use of neuronal isoforms of the proteins that mediate endocytosis.
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Affiliation(s)
- N Jarousse
- Department of Biochemistry and Biophysics, University of California, San Francisco, 94143-0448, USA
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43
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Micheva KD, Holz RW, Smith SJ. Regulation of presynaptic phosphatidylinositol 4,5-biphosphate by neuronal activity. J Cell Biol 2001; 154:355-68. [PMID: 11470824 PMCID: PMC2150764 DOI: 10.1083/jcb.200102098] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol 4,5-biphosphate (PIP2) has been implicated in a variety of cellular processes, including synaptic vesicle recycling. However, little is known about the spatial distribution of this phospholipid in neurons and its dynamics. In this study, we have focused on these questions by transiently expressing the phospholipase C (PLC)-delta1 pleckstrin homology (PH) domain fused to green fluorescent protein (GFP) in cultured hippocampal neurons. This PH domain binds specifically and with high affinity to PIP2. Live confocal imaging revealed that in resting cells, PH-GFP is localized predominantly on the plasma membrane. Interestingly, no association of PH-GFP with synaptic vesicles in quiescent neurons was observed, indicating the absence of detectable PIP2 on mature synaptic vesicles. Electrical stimulation of hippocampal neurons resulted in a decrease of the PH-GFP signal at the plasma membrane, most probably due to a PLC-mediated hydrolysis of PIP2. This was accompanied in the majority of presynaptic terminals by a marked increase in the cytoplasmic PH-GFP signal, localized most probably on freshly endocytosed membranes. Further investigation revealed that the increase in PH-GFP signal was dependent on the activation of N-methyl-D-aspartate receptors and the consequent production of nitric oxide (NO). Thus, PIP2 in the presynaptic terminal appears to be regulated by postsynaptic activity via a retrograde action of NO.
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Affiliation(s)
- K D Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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44
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Abstract
The release of neurotransmitter from neurons represents one of the pivotal events in synaptic transmission. Neurotransmitters are released from synaptic vesicles in presynaptic neurons in response to neural activity, diffuse across the synaptic cleft, and bind specific receptors in order to bring about changes in postsynaptic neurons. Some of the molecular processes that govern neurotransmitter release are now becoming better understood. The steps involved can be broken down into two partially overlapping presynaptic cycles, the neurotransmitter cycle and the synaptic vesicle cycle. The neurotransmitter cycle involves transmitter biosynthesis, storage, reuptake, and degradation. The synaptic vesicle cycle involves targeting to the nerve terminal, docking, fusion, endocytosis, and recycling. Biochemical and structural studies have yielded important insight into our understanding of each of these two cycles. Further, both pharmacological and genetic interference with either of these cycles results in profound alterations in synaptic transmission and behavior, demonstrating the crucial role of neurotransmitter release.
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Affiliation(s)
- E A Fon
- Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec H3A 2B4, Canada.
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45
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Abstract
Inositol phospholipids represent a minor fraction of membrane phospholipids; yet they play important regulatory functions in signaling pathways and membrane traffic. The phosphorylated inositol ring can act either as a precursor for soluble intracellular messengers or as a binding site for cytosolic or membrane proteins. Hence, phosphorylation-dephosphorylation of phosphoinositides represents a mechanism for regulation of recruitment to the membrane of coat proteins, cytoskeletal scaffolds or signaling complexes and for the regulation of membrane proteins. Recent work suggests that phosphoinositide metabolism has an important role in membrane traffic at the synapse. PtdIns(4,5)P(2) generation is implicated in the secretion of at least a subset of neurotransmitters. Furthermore, PtdIns(4,5)P(2) plays a role in the nucleation of clathrin coats and of an actin-based cytoskeletal scaffold at endocytic zones of synapses, and PtdIns(4,5)P(2) dephosphorylation accompanies the release of newly formed vesicles from these interactions. Thus, the reversible phosphorylation of inositol phospholipids may be one of the mechanisms governing the timing and vectorial progression of synaptic vesicle membranes during their exocytic-endocytic cycle.
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Affiliation(s)
- O Cremona
- Department of Medical Sciences, Università del Piemonte Orientale 'A. Avogadro', Via Solaroli 17, Italy.
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46
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Avshalumov MV, Chen BT, Rice ME. Mechanisms underlying H(2)O(2)-mediated inhibition of synaptic transmission in rat hippocampal slices. Brain Res 2000; 882:86-94. [PMID: 11056187 DOI: 10.1016/s0006-8993(00)02835-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hydrogen peroxide (H(2)O(2)) inhibits the population spike (PS) evoked by Schaffer collateral stimulation in hippocampal slices. Proposed mechanisms underlying this effect include generation of hydroxyl radicals (.OH) and inhibition of presynaptic Ca(2+) entry. We have examined these possible mechanisms in rat hippocampal slices. Inhibition of the evoked PS by H(2)O(2) was sharply concentration-dependent: 1.2 mM H(2)O(2) had no effect, whereas 1.5 and 2.0 mM H(2)O(2) reversibly depressed PS amplitude by roughly 80%. The iron chelator, deferoxamine (1 mM), and the endogenous.OH scavenger, ascorbate (400 microM), prevented PS inhibition, confirming.OH involvement. Isoascorbate (400 microM), which unlike ascorbate is not taken up by brain cells, also prevented PS inhibition, indicating an extracellular site of.OH generation or action. We then investigated whether H(2)O(2)-induced PS depression could be overcome by prolonged stimulation, which enhances Ca(2+) entry. During 5-s, 10-Hz trains under control conditions, PS amplitude increased to over 200% during the first three-four pulses, then stabilized. In the presence of H(2)O(2), PS amplitude was initially depressed, but began to recover after 2.5 s of stimulation, finally reaching 80% of the control maximum. In companion experiments, we assessed the effect of H(2)O(2) on presynaptic Ca(2+) entry by monitoring extracellular Ca(2+) concentration ([Ca(2+)](o)) during train stimulation in the presence of postsynaptic receptor blockers. Evoked [Ca(2+)](o) shifts were apparently unaltered by H(2)O(2), suggesting a lack of effect on Ca(2+) entry. Taken together, these findings suggest new ways in which reactive oxygen species (ROS) might act as signaling agents, specifically as modulators of synaptic transmission.
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Affiliation(s)
- M V Avshalumov
- Departments of Physiology and Neuroscience and Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Yauch RL, Hemler ME. Specific interactions among transmembrane 4 superfamily (TM4SF) proteins and phosphoinositide 4-kinase. Biochem J 2000; 351 Pt 3:629-37. [PMID: 11042117 PMCID: PMC1221402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
In earlier work we established that phosphoinositide 4-kinase (PI 4-kinase) may associate with transmembrane 4 superfamily (TM4SF, tetraspanin) proteins, but critical specificity issues were not addressed. Here we demonstrate that at least five different TM4SF proteins (CD9, CD63, CD81, CD151 and A15/TALLA1) can associate with a similar or identical 55 kDa type II PI 4-kinase. These associations were specific, since we found no evidence for other phosphoinositide kinases (e.g. phosphoinositide 3-kinase and phosphoinositide-4-phosphate 5-kinase) associating with TM4SF proteins, and many other TM4SF proteins (including CD82 and CD53) did not associate with PI 4-kinase. CD63-PI 4-kinase complexes were almost entirely intracellular, and thus are distinct from other TM4SF-PI 4-kinase complexes (e.g. involving CD9), which are largely located in the plasma membrane. These results suggest that a specific subset of TM4SF proteins may recruit PI 4-kinase to specific membrane locations, and thereby influence phosphoinositide-dependent signalling.
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Affiliation(s)
- R L Yauch
- Dana-Farber Cancer Institute, Rm D-1430, 44 Binney Street, Boston, MA 02115, USA
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Bartlett SE, Reynolds AJ, Weible M, Jeromin A, Roder J, Hendry IA. PtdIns 4-kinasebeta and neuronal calcium sensor-1 co-localize but may not directly associate in mammalian neurons. J Neurosci Res 2000; 62:216-24. [PMID: 11020214 DOI: 10.1002/1097-4547(20001015)62:2<216::aid-jnr6>3.0.co;2-a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It was recently demonstrated that the yeast homologue of phosphatidylinositol 4-kinasebeta PIK1 is directly associated with frq1, the yeast homologue of mammalian neuronal calcium sensor-1 (NCS-1) (Hendricks et al., [1999] Nat. Cell Biol. 1:234- 241). This was a novel finding and suggests that a calcium binding protein activates and regulates PtdIns 4-kinasebeta. This finding had not been shown in mammalian cells and both PtdIns 4-kinasebeta and NCS-1 have been shown to have important roles in the regulation of exocytotic release associated with neurotransmission. The aims of this study were to determine if PtdIns 4-kinasebeta and NCS-1 directly associate in mammalian neural tissues. We show that the immunostaining pattern for PtdIns 4-kinasebeta and NCS-1 is co-localized throughout the neurites of newborn cultured dorsal root ganglia (DRG) neurons but not in E13 DRG neurons. We then provide biochemical evidence that PtdIns 4-kinasebeta may not be in physical association with NCS-1 in mammalian nervous tissue unlike that previously reported in yeast.
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Affiliation(s)
- S E Bartlett
- Division of Neuroscience, The John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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Reynolds AJ, Bartlett SE, Hendry IA. Molecular mechanisms regulating the retrograde axonal transport of neurotrophins. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 33:169-78. [PMID: 11011064 DOI: 10.1016/s0165-0173(00)00028-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neurotrophins are released from target tissues following neural innervation and bind to specific receptors situated on the nerve terminal plasma membrane. The neurotrophin-receptor complex undergoes retrograde axonal transport towards the cell soma, where it signals to the nucleus. This process allows neurotrophins to perform their numerous functions, which include the promotion of neuronal survival and the outgrowth of axons towards certain target tissues. The molecular events controlling each of the components of retrograde axonal transport are beginning to become defined. There is good evidence for the participation of phosphatidylinositol 3-kinase, phosphatidylinositol 4-kinase and the actin cytoskeleton in neurotrophin retrograde axonal transport in vivo. It also appears that the retrograde motor protein dynein mediates the retrograde axonal transport in vivo of neurotrophins such as nerve growth factor. This review discusses the role of the neurotrophin receptors in binding and axonal transport, the endocytic processes required for neurotrophin internalization, the targeting and trafficking of neurotrophins, and the propagation of neurotrophin-induced signals along the axon.
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Affiliation(s)
- A J Reynolds
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, GPO Box 334, ACT 2601, Canberra, Australia.
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Weisz OA, Gibson GA, Leung SM, Roder J, Jeromin A. Overexpression of frequenin, a modulator of phosphatidylinositol 4-kinase, inhibits biosynthetic delivery of an apical protein in polarized madin-darby canine kidney cells. J Biol Chem 2000; 275:24341-7. [PMID: 10825156 DOI: 10.1074/jbc.m000671200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyphosphoinositides regulate numerous steps in membrane transport. The levels of individual phosphatidylinositols are controlled by specific lipid kinases, whose activities and localization are in turn regulated by a variety of effectors. Here we have examined the effect of overexpression of frequenin, a modulator of phosphatidylinositol 4-kinase activity, on biosynthetic and postendocytic traffic in polarized Madin-Darby canine kidney cells. Endogenous frequenin was identified in these cells by polymerase chain reaction, Western blotting, and indirect immunofluorescence. Adenoviral-mediated overexpression of frequenin had no effect on early Golgi transport of membrane proteins, as assessed by acquisition of resistance to endoglycosidase H. However, delivery of newly synthesized influenza hemagglutinin from the trans-Golgi network to the apical cell surface was severely inhibited in cells overexpressing frequenin, whereas basolateral delivery of the polymeric immunoglobulin receptor was unaffected. Overexpression of frequenin did not affect postendocytic trafficking steps including apical and basolateral recycling and basal-to-apical transcytosis. We conclude that frequenin, and by inference, phosphatidylinositol 4-kinase, plays an important and selective role in apical delivery in polarized cells.
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Affiliation(s)
- O A Weisz
- Laboratory of Epithelial Cell Biology, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
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