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Golding AE, Li W, Blank PS, Cologna SM, Zimmerberg J. Relative quantification of progressive changes in healthy and dysferlin-deficient mouse skeletal muscle proteomes. Muscle Nerve 2023; 68:805-816. [PMID: 37706611 DOI: 10.1002/mus.27975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/15/2023]
Abstract
INTRODUCTION/AIMS Individuals with dysferlinopathies, a group of genetic muscle diseases, experience delay in the onset of muscle weakness. The cause of this delay and subsequent muscle wasting are unknown, and there are currently no clinical interventions to limit or prevent muscle weakness. To better understand molecular drivers of dysferlinopathies, age-dependent changes in the proteomic profile of skeletal muscle (SM) in wild-type (WT) and dysferlin-deficient mice were identified. METHODS Quadriceps were isolated from 6-, 18-, 42-, and 77-wk-old C57BL/6 (WT, Dysf+/+ ) and BLAJ (Dysf-/- ) mice (n = 3, 2 male/1 female or 1 male/2 female, 24 total). Whole-muscle proteomes were characterized using liquid chromatography-mass spectrometry with relative quantification using TMT10plex isobaric labeling. Principle component analysis was utilized to detect age-dependent proteomic differences over the lifespan of, and between, WT and dysferlin-deficient SM. The biological relevance of proteins with significant variation was established using Ingenuity Pathway Analysis. RESULTS Over 3200 proteins were identified between 6-, 18-, 42-, and 77-wk-old mice. In total, 46 proteins varied in aging WT SM (p < .01), while 365 varied in dysferlin-deficient SM. However, 569 proteins varied between aged-matched WT and dysferlin-deficient SM. Proteins with significant variation in expression across all comparisons followed distinct temporal trends. DISCUSSION Proteins involved in sarcolemma repair and regeneration underwent significant changes in SM over the lifespan of WT mice, while those associated with immune infiltration and inflammation were overly represented over the lifespan of dysferlin-deficient mice. The proteins identified herein are likely to contribute to our overall understanding of SM aging and dysferlinopathy disease progression.
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Affiliation(s)
- Adriana E Golding
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Section on Intracellular Protein Trafficking, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Wenping Li
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois, USA
| | - Paul S Blank
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Stephanie M Cologna
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois, USA
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Wang XT, Zhou L, Dong BB, Xu FX, Wang DJ, Shen EW, Cai XY, Wang Y, Wang N, Ji SJ, Chen W, Schonewille M, Zhu JJ, De Zeeuw CI, Shen Y. cAMP-EPAC-PKCε-RIM1α signaling regulates presynaptic long-term potentiation and motor learning. eLife 2023; 12:e80875. [PMID: 37159499 PMCID: PMC10171863 DOI: 10.7554/elife.80875] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 04/25/2023] [Indexed: 05/11/2023] Open
Abstract
The cerebellum is involved in learning of fine motor skills, yet whether presynaptic plasticity contributes to such learning remains elusive. Here, we report that the EPAC-PKCε module has a critical role in a presynaptic form of long-term potentiation in the cerebellum and motor behavior in mice. Presynaptic cAMP-EPAC-PKCε signaling cascade induces a previously unidentified threonine phosphorylation of RIM1α, and thereby initiates the assembly of the Rab3A-RIM1α-Munc13-1 tripartite complex that facilitates docking and release of synaptic vesicles. Granule cell-specific blocking of EPAC-PKCε signaling abolishes presynaptic long-term potentiation at the parallel fiber to Purkinje cell synapses and impairs basic performance and learning of cerebellar motor behavior. These results unveil a functional relevance of presynaptic plasticity that is regulated through a novel signaling cascade, thereby enriching the spectrum of cerebellar learning mechanisms.
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Affiliation(s)
- Xin-Tai Wang
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
- Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
| | - Lin Zhou
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Bin-Bin Dong
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Fang-Xiao Xu
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - De-Juan Wang
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - En-Wei Shen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Xin-Yu Cai
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Yin Wang
- Key Laboratory of Cranial Cerebral Diseases, Department of Neurobiology of Basic Medical College, Ningxia Medical UniversityYinchuanChina
| | - Na Wang
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Sheng-Jian Ji
- Department of Biology, Southern University of Science and TechnologyShenzhenChina
| | - Wei Chen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
| | | | - J Julius Zhu
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MCRotterdamNetherlands
- Netherlands Institute for Neuroscience, Royal Academy of SciencesAmsterdamNetherlands
| | - Ying Shen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhouChina
- International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of MedicineYiwuChina
- Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of MedicineHangzhouChina
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Xue R, Meng H, Yin J, Xia J, Hu Z, Liu H. The Role of Calmodulin vs. Synaptotagmin in Exocytosis. Front Mol Neurosci 2021; 14:691363. [PMID: 34421537 PMCID: PMC8375295 DOI: 10.3389/fnmol.2021.691363] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/19/2021] [Indexed: 12/04/2022] Open
Abstract
Exocytosis is a Ca2+-regulated process that requires the participation of Ca2+ sensors. In the 1980s, two classes of Ca2+-binding proteins were proposed as putative Ca2+ sensors: EF-hand protein calmodulin, and the C2 domain protein synaptotagmin. In the next few decades, numerous studies determined that in the final stage of membrane fusion triggered by a micromolar boost in the level of Ca2+, the low affinity Ca2+-binding protein synaptotagmin, especially synaptotagmin 1 and 2, acts as the primary Ca2+ sensor, whereas calmodulin is unlikely to be functional due to its high Ca2+ affinity. However, in the meantime emerging evidence has revealed that calmodulin is involved in the earlier exocytotic steps prior to fusion, such as vesicle trafficking, docking and priming by acting as a high affinity Ca2+ sensor activated at submicromolar level of Ca2+. Calmodulin directly interacts with multiple regulatory proteins involved in the regulation of exocytosis, including VAMP, myosin V, Munc13, synapsin, GAP43 and Rab3, and switches on key kinases, such as type II Ca2+/calmodulin-dependent protein kinase, to phosphorylate a series of exocytosis regulators, including syntaxin, synapsin, RIM and Ca2+ channels. Moreover, calmodulin interacts with synaptotagmin through either direct binding or indirect phosphorylation. In summary, calmodulin and synaptotagmin are Ca2+ sensors that play complementary roles throughout the process of exocytosis. In this review, we discuss the complementary roles that calmodulin and synaptotagmin play as Ca2+ sensors during exocytosis.
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Affiliation(s)
- Renhao Xue
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Hao Meng
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Jiaxiang Yin
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Jingyao Xia
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Zhitao Hu
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Huisheng Liu
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
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Active Zone Proteins RIM1αβ Are Required for Normal Corticostriatal Transmission and Action Control. J Neurosci 2018; 39:1457-1470. [PMID: 30559150 DOI: 10.1523/jneurosci.1940-18.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/13/2018] [Accepted: 12/04/2018] [Indexed: 11/21/2022] Open
Abstract
Dynamic regulation of synaptic transmission at cortical inputs to the dorsal striatum is considered critical for flexible and efficient action learning and control. Presynaptic mechanisms governing the properties and plasticity of glutamate release from these inputs are not fully understood, and the corticostriatal synaptic processes that support normal action learning and control remain unclear. Here we show in male and female mice that conditional deletion of presynaptic proteins RIM1αβ (RIM1) from excitatory cortical neurons impairs corticostriatal synaptic transmission in the dorsolateral striatum. Key forms of presynaptic G-protein-coupled receptor-mediated short- and long-term striatal plasticity are spared following RIM1 deletion. Conditional RIM1 KO mice show heightened novelty-induced locomotion and impaired motor learning on the accelerating rotarod. They further show heightened self-paced instrumental responding for food and impaired learning of a habitual instrumental response strategy. Together, these findings reveal a selective role for presynaptic RIM1 in neurotransmitter release at prominent basal ganglia synapses, and provide evidence that RIM1-dependent processes help to promote the refinement of skilled actions, constrain goal-directed behaviors, and support the learning and use of habits.SIGNIFICANCE STATEMENT Our daily functioning hinges on the ability to flexibly and efficiently learn and control our actions. How the brain encodes these capacities is unclear. Here we identified a selective role for presynaptic proteins RIM1αβ in controlling glutamate release from cortical inputs to the dorsolateral striatum, a brain structure critical for action learning and control. Behavioral analysis of mice with restricted genetic deletion of RIM1αβ further revealed roles for RIM1αβ-dependent processes in the learning and refinement of motor skills and the balanced expression of goal-directed and habitual actions.
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5
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Maselli RA, Vázquez J, Schrumpf L, Arredondo J, Lara M, Strober JB, Pytel P, Wollmann RL, Ferns M. Presynaptic congenital myasthenic syndrome with altered synaptic vesicle homeostasis linked to compound heterozygous sequence variants in RPH3A. Mol Genet Genomic Med 2018; 6:434-440. [PMID: 29441694 PMCID: PMC6014458 DOI: 10.1002/mgg3.370] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 01/06/2018] [Accepted: 11/20/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Monogenic defects of synaptic vesicle (SV) homeostasis have been implicated in many neurologic diseases, including autism, epilepsy, and movement disorders. In addition, abnormal vesicle exocytosis has been associated with several endocrine dysfunctions. METHODS We report an 11 year old girl with learning disabilities, tremors, ataxia, transient hyperglycemia, and muscle fatigability responsive to albuterol sulfate. Failure of neuromuscular transmission was confirmed by single fiber electromyography. Electron microscopy of motor nerve terminals revealed marked reduction in SV density, double-membrane-bound sacs containing SVs, abundant endosomes, and degenerative lamellar bodies. The patient underwent whole exome sequencing (WES) and relevant sequence variants were expressed and studied in a mammalian cell line. RESULTS Chromosomal microarray studies and next generation sequencing (NGS) of mitochondrial DNA were unrevealing; however, NGS of genomic DNA showed two rare sequence variants in the gene encoding rabphilin 3a (RPH3A). The paternally inherited variant c.806 G>A (p.Arg269Gln) involves a substitution of a conserved residue in the linker region, while the maternally inherited variant c.1390 G>T (p.Val464Leu) involves a conserved amino acid substitution in the highly conserved C2A region. Expression studies revealed that p.Arg269Gln strongly impairs the binding of rabphilin 3a to 14-3-3, which is a proposed regulator of synaptic transmission and plasticity. In contrast, the binding of rabphilin 3a to 14-3-3 is only marginally impaired by p.Val464Leu; thus, the pathogenic role of p.Val464Leu remains unclear. CONCLUSION In summary, we report a patient with a multisystem neurologic disorder and altered SV regulation attributed to defects in RPH3A, which grants further studies of this gene in human disorders of synaptic transmission.
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Affiliation(s)
| | - Jessica Vázquez
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Leah Schrumpf
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Juan Arredondo
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Marian Lara
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Jonathan B. Strober
- Department of NeurologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Peter Pytel
- Department of PathologyUniversity of ChicagoChicagoILUSA
| | | | - Michael Ferns
- Department of Anesthesiology and Pain MedicineUniversity of California DavisSacramentoCAUSA
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14-3-3 Proteins in Glutamatergic Synapses. Neural Plast 2018; 2018:8407609. [PMID: 29849571 PMCID: PMC5937437 DOI: 10.1155/2018/8407609] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 03/13/2018] [Accepted: 03/27/2018] [Indexed: 11/18/2022] Open
Abstract
The 14-3-3 proteins are a family of proteins that are highly expressed in the brain and particularly enriched at synapses. Evidence accumulated in the last two decades has implicated 14-3-3 proteins as an important regulator of synaptic transmission and plasticity. Here, we will review previous and more recent research that has helped us understand the roles of 14-3-3 proteins at glutamatergic synapses. A key challenge for the future is to delineate the 14-3-3-dependent molecular pathways involved in regulating synaptic functions.
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7
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Satnav for cells: Destination membrane fusion. Cell Calcium 2017; 68:14-23. [PMID: 29129204 DOI: 10.1016/j.ceca.2017.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/20/2017] [Accepted: 10/07/2017] [Indexed: 11/23/2022]
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8
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Trexler AJ, Taraska JW. Regulation of insulin exocytosis by calcium-dependent protein kinase C in beta cells. Cell Calcium 2017; 67:1-10. [PMID: 29029784 DOI: 10.1016/j.ceca.2017.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 12/27/2022]
Abstract
The control of insulin release from pancreatic beta cells helps ensure proper blood glucose level, which is critical for human health. Protein kinase C has been shown to be one key control mechanism for this process. After glucose stimulation, calcium influx into beta cells triggers exocytosis of insulin-containing dense-core granules and activates protein kinase C via calcium-dependent phospholipase C-mediated generation of diacylglycerol. Activated protein kinase C potentiates insulin release by enhancing the calcium sensitivity of exocytosis, likely by affecting two main pathways that could be linked: (1) the reorganization of the cortical actin network, and (2) the direct phosphorylation of critical exocytotic proteins such as munc18, SNAP25, and synaptotagmin. Here, we review what is currently known about the molecular mechanisms of protein kinase C action on each of these pathways and how these effects relate to the control of insulin release by exocytosis. We identify remaining challenges in the field and suggest how these challenges might be addressed to advance our understanding of the regulation of insulin release in health and disease.
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Affiliation(s)
- Adam J Trexler
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Justin W Taraska
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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9
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Lim GE, Piske M, Lulo JE, Ramshaw HS, Lopez AF, Johnson JD. Ywhaz/14-3-3ζ Deletion Improves Glucose Tolerance Through a GLP-1-Dependent Mechanism. Endocrinology 2016; 157:2649-59. [PMID: 27167773 DOI: 10.1210/en.2016-1016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple signaling pathways mediate the actions of metabolic hormones to control glucose homeostasis, but the proteins that coordinate such networks are poorly understood. We previously identified the molecular scaffold protein, 14-3-3ζ, as a critical regulator of in vitro β-cell survival and adipogenesis, but its metabolic roles in glucose homeostasis have not been studied in depth. Herein, we report that Ywhaz gene knockout mice (14-3-3ζKO) exhibited elevated fasting insulin levels while maintaining normal β-cell responsiveness to glucose when compared with wild-type littermate controls. In contrast with our observations after an ip glucose bolus, glucose tolerance was significantly improved in 14-3-3ζKO mice after an oral glucose gavage. This improvement in glucose tolerance was associated with significantly elevated fasting glucagon-like peptide-1 (GLP-1) levels. 14-3-3ζ knockdown in GLUTag L cells elevated GLP-1 synthesis and increased GLP-1 release. Systemic inhibition of the GLP-1 receptor attenuated the improvement in oral glucose tolerance that was seen in 14-3-3ζKO mice. When taken together these findings demonstrate novel roles of 14-3-3ζ in the regulation of glucose homeostasis and suggest that modulating 14-3-3ζ levels in intestinal L cells may have beneficial metabolic effects through GLP-1-dependent mechanisms.
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Affiliation(s)
- Gareth E Lim
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
| | - Micah Piske
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
| | - James E Lulo
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
| | - Hayley S Ramshaw
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
| | - Angel F Lopez
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
| | - James D Johnson
- Department of Cellular and Physiological Sciences (G.E.L., M.P., J.D.J.), University of British Columbia, Vancouver, BC, Canada; ALPCO (J.E.L.), Salem, New Hampshire; and The Centre for Cancer Biology (H.S.R., A.F.L.), South Australia Pathology and University of South Australia, Adelaide, Australia
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Cárdenas AM, Marengo FD. How the stimulus defines the dynamics of vesicle pool recruitment, fusion mode, and vesicle recycling in neuroendocrine cells. J Neurochem 2016; 137:867-79. [DOI: 10.1111/jnc.13565] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 01/05/2016] [Accepted: 01/25/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Ana María Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso; Universidad de Valparaíso; Valparaíso Chile
| | - Fernando D. Marengo
- Laboratorio de Fisiología y Biología Molecular; Instituto de Fisiología; Biología Molecular y Neurociencias (CONICET); Departamento de Fisiología y Biología Molecular y Celular; Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; Buenos Aires Argentina
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Wang Y, Iqbal J, Liu Y, Su R, Lu S, Peng G, Zhang Y, Qing H, Deng Y. Effects of simulated microgravity on the expression of presynaptic proteins distorting the GABA/glutamate equilibrium - A proteomics approach. Proteomics 2015; 15:3883-91. [DOI: 10.1002/pmic.201500302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/28/2015] [Accepted: 09/07/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Yun Wang
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Javed Iqbal
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Yahui Liu
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Rui Su
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Song Lu
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Guang Peng
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Yongqian Zhang
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Hong Qing
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
| | - Yulin Deng
- School of Life Sciences; Beijing Institute of Technology; Beijing P.R. China
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Abstract
This review considers pharmacogenetics of the so called 'second-generation' antipsychotics. Findings for polymorphisms replicating in more than one study are emphasized and compared and contrasted with larger-scale candidate gene studies and genome-wide association study analyses. Variants in three types of genes are discussed: pharmacokinetic genes associated with drug metabolism and disposition, pharmacodynamic genes encoding drug targets, and pharmacotypic genes impacting disease presentation and subtype. Among pharmacokinetic markers, CYP2D6 metabolizer phenotype has clear clinical significance, as it impacts dosing considerations for aripiprazole, iloperidone and risperidone, and variants of the ABCB1 gene hold promise as biomarkers for dosing for olanzapine and clozapine. Among pharmacodynamic variants, the TaqIA1 allele of the DRD2 gene, the DRD3 (Ser9Gly) polymorphism, and the HTR2C -759C/T polymorphism have emerged as potential biomarkers for response and/or side effects. However, large-scale candidate gene studies and genome-wide association studies indicate that pharmacotypic genes may ultimately prove to be the richest source of biomarkers for response and side effect profiles for second-generation antipsychotics.
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Affiliation(s)
- Mark D Brennan
- Department of Biochemistry & Molecular Biology, School of Medicine, University of Louisville, Louisville, KY 40292, USA.
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Álvarez YD, Belingheri AV, Perez Bay AE, Javis SE, Tedford HW, Zamponi G, Marengo FD. The immediately releasable pool of mouse chromaffin cell vesicles is coupled to P/Q-type calcium channels via the synaptic protein interaction site. PLoS One 2013; 8:e54846. [PMID: 23382986 PMCID: PMC3559834 DOI: 10.1371/journal.pone.0054846] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 12/18/2012] [Indexed: 01/17/2023] Open
Abstract
It is generally accepted that the immediately releasable pool is a group of readily releasable vesicles that are closely associated with voltage dependent Ca2+ channels. We have previously shown that exocytosis of this pool is specifically coupled to P/Q Ca2+ current. Accordingly, in the present work we found that the Ca2+ current flowing through P/Q-type Ca2+ channels is 8 times more effective at inducing exocytosis in response to short stimuli than the current carried by L-type channels. To investigate the mechanism that underlies the coupling between the immediately releasable pool and P/Q-type channels we transiently expressed in mouse chromaffin cells peptides corresponding to the synaptic protein interaction site of Cav2.2 to competitively uncouple P/Q-type channels from the secretory vesicle release complex. This treatment reduced the efficiency of Ca2+ current to induce exocytosis to similar values as direct inhibition of P/Q-type channels via ω-agatoxin-IVA. In addition, the same treatment markedly reduced immediately releasable pool exocytosis, but did not affect the exocytosis provoked by sustained electric or high K+ stimulation. Together, our results indicate that the synaptic protein interaction site is a crucial factor for the establishment of the functional coupling between immediately releasable pool vesicles and P/Q-type Ca2+ channels.
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Affiliation(s)
- Yanina D. Álvarez
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología, Biología Molecular y Neurociencias (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ana Verónica Belingheri
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología, Biología Molecular y Neurociencias (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andrés E. Perez Bay
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología, Biología Molecular y Neurociencias (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Scott E. Javis
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - H. William Tedford
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Gerald Zamponi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Fernando D. Marengo
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología, Biología Molecular y Neurociencias (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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Raftogianni A, Stamatakis A, Papadopoulou A, Vougas K, Anagnostopoulos AK, Stylianopoulou F, Tsangaris GT. Effects of an early experience of reward through maternal contact or its denial on laterality of protein expression in the developing rat hippocampus. PLoS One 2012; 7:e48337. [PMID: 23118990 PMCID: PMC3485191 DOI: 10.1371/journal.pone.0048337] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 09/24/2012] [Indexed: 01/01/2023] Open
Abstract
Laterality is a basic characteristic of the brain which is detectable early in life. Although early experiences affect laterality of the mature brain, there are no reports on their immediate neurochemical effects during neonatal life, which could provide evidence as to the mechanisms leading to the lateralized brain. In order to address this issue, we determined the differential protein expression profile of the left and right hippocampus of 13-day-old rat control (CTR) pups, as well as following exposure to an early experience involving either receipt (RER) or denial (DER) of the expected reward of maternal contact. Proteomic analysis was performed by 2-dimensional polyacrylamide gel electrophoresis (PAGE) followed by mass spectroscopy. The majority of proteins found to be differentially expressed either between the three experimental groups (DER, RER, CTR) or between the left and right hemisphere were cytoskeletal (34%), enzymes of energy metabolism (32%), and heat shock proteins (17%). In all three groups more proteins were up-regulated in the left compared to the right hippocampus. Tubulins were found to be most often up-regulated, always in the left hippocampus. The differential expression of β-tubulin, β-actin, dihydropyrimidinase like protein 1, glial fibrillary acidic protein (GFAP) and Heat Shock protein 70 revealed by the proteomic analysis was in general confirmed by Western blots. Exposure to the early experience affected brain asymmetry: In the RER pups the ratio of proteins up-regulated in the left hippocampus to those in the right was 1.8, while the respective ratio was 3.6 in the CTR and 3.4 in the DER. Our results could contribute to the elucidation of the cellular mechanisms mediating the effects of early experiences on the vulnerability for psychopathology, since proteins shown in our study to be differentially expressed (e.g. tubulins, dihydropyrimidinase like proteins, 14-3-3 protein, GFAP, ATP synthase, α-internexin) have also been identified in proteomic analyses of post-mortem brains from psychiatric patients.
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Affiliation(s)
- Androniki Raftogianni
- Laboratory of Biology-Biochemistry, Department of Basic Sciences, School of Health Sciences, University of Athens, Athens, Greece
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15
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Kasai H, Takahashi N, Tokumaru H. Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis. Physiol Rev 2012; 92:1915-64. [DOI: 10.1152/physrev.00007.2012] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.
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Affiliation(s)
- Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Noriko Takahashi
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Hiroshi Tokumaru
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
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16
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Brozzi F, Lajus S, Diraison F, Rajatileka S, Hayward K, Regazzi R, Molnár E, Váradi A. MyRIP interaction with MyoVa on secretory granules is controlled by the cAMP-PKA pathway. Mol Biol Cell 2012; 23:4444-55. [PMID: 22993210 PMCID: PMC3496617 DOI: 10.1091/mbc.e12-05-0369] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Myosin- and Rab-interacting protein is not a classic receptor for MyoVa on large, dense-core secretory granules (SGs), but it aids in PKA-dependent phosphorylation of MyoVa-associated proteins on SGs in endocrine and neuroendocrine cells. Myosin- and Rab-interacting protein (MyRIP), which belongs to the protein kinase A (PKA)–anchoring family, is implicated in hormone secretion. However, its mechanism of action is not fully elucidated. Here we investigate the role of MyRIP in myosin Va (MyoVa)-dependent secretory granule (SG) transport and secretion in pancreatic beta cells. These cells solely express the brain isoform of MyoVa (BR-MyoVa), which is a key motor protein in SG transport. In vitro pull-down, coimmunoprecipitation, and colocalization studies revealed that MyRIP does not interact with BR-MyoVa in glucose-stimulated pancreatic beta cells, suggesting that, contrary to previous notions, MyRIP does not link this motor protein to SGs. Glucose-stimulated insulin secretion is augmented by incretin hormones, which increase cAMP levels and leads to MyRIP phosphorylation, its interaction with BR-MyoVa, and phosphorylation of the BR-MyoVa receptor rabphilin-3A (Rph-3A). Rph-3A phosphorylation on Ser-234 was inhibited by small interfering RNA knockdown of MyRIP, which also reduced cAMP-mediated hormone secretion. Demonstrating the importance of this phosphorylation, nonphosphorylatable and phosphomimic Rph-3A mutants significantly altered hormone release when PKA was activated. These data suggest that MyRIP only forms a functional protein complex with BR-MyoVa on SGs when cAMP is elevated and under this condition facilitates phosphorylation of SG-associated proteins, which in turn can enhance secretion.
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Affiliation(s)
- Flora Brozzi
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, University of the West of England, Bristol BS16 1QY, United Kingdom
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17
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Gandini MA, Felix R. Functional interactions between voltage-gated Ca(2+) channels and Rab3-interacting molecules (RIMs): new insights into stimulus-secretion coupling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:551-8. [PMID: 22198390 DOI: 10.1016/j.bbamem.2011.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 12/27/2022]
Abstract
Stimulus-secretion coupling is a complex set of intracellular reactions initiated by an external stimulus that result in the release of hormones and neurotransmitters. Under physiological conditions this signaling process takes a few milliseconds, and to minimize delays cells have developed a formidable integrated network, in which the relevant molecules are tightly packed on the nanometer scale. Active zones, the sites of release, are composed of several different proteins including voltage-gated Ca(2+) (Ca(V)) channels. It is well acknowledged that hormone and neurotransmitter release is initiated by the activation of these channels located close to docked vesicles, though the mechanisms that enrich channels at release sites are largely unknown. Interestingly, Rab3 binding proteins (RIMs), a diverse multidomain family of proteins that operate as effectors of the small G protein Rab3 involved in secretory vesicle trafficking, have recently identified as binding partners of Ca(V) channels, placing both proteins in the center of an interaction network in the molecular anatomy of the active zones that influence different aspects of secretion. Here, we review recent evidences providing support for the notion that RIMs directly bind to the pore-forming and auxiliary β subunits of Ca(V) channels and with RIM-binding protein, another interactor of the channels. Through these interactions, RIMs regulate the biophysical properties of the channels and their anchoring relative to active zones, significantly influencing hormone and neurotransmitter release.
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Affiliation(s)
- María A Gandini
- Department of Cell Biology, National Polytechnic Institute, Mexico City, Mexico
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18
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Escitalopram modulates neuron-remodelling proteins in a rat gene-environment interaction model of depression as revealed by proteomics. Part I: genetic background. Int J Neuropsychopharmacol 2011; 14:796-833. [PMID: 21054914 DOI: 10.1017/s1461145710001318] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The wide-scale analysis of protein expression provides a powerful strategy for the molecular exploration of complex pathophysiological mechanisms, such as the response to antidepressants. Using a 2D proteomic approach we investigated the Flinders Sensitive Line (FSL), a genetically selected rat model of depression, and the control Flinders Resistant Line (FRL). To evaluate gene-environment interactions, FSL and FRL pups were separated from their mothers for 3 h (maternal separation, MS), as early-life trauma is considered an important antecedent of depression. All groups were treated with either escitalopram (Esc) admixed to food (25 mg/kg.d) or vehicle for 1 month. At the week 3, forced swim tests were performed. Protein extracts from prefrontal/frontal cortex and hippocampus were separated by 2D electrophoresis. Proteins displaying statistically significant differences in expression levels were identified by mass spectrometry. Immobility time values in the forced swim test were higher in FSL rats and reduced by antidepressant treatment. Moreover, the Esc-induced reduction in immobility time was not detected in MS rats. The impact of genetic background in response to Esc was specifically investigated here. Bioinformatics analyses highlighted gene ontology terms showing tighter associations with the modulated proteins. Esc modulated protein belonging to cytoskeleton organization in FSL; carbohydrate metabolism and intracellular transport in FRL. Proteins differently modulated in the two strains after MS and Esc play a role in cytoskeleton organization, vesicle-mediated transport, apoptosis regulation and macromolecule catabolism. These findings suggest pathways involved in neuronal remodelling as molecular correlates of response to antidepressants in a model of vulnerability.
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19
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Regulation of cytoskeleton machinery, neurogenesis and energy metabolism pathways in a rat gene-environment model of depression revealed by proteomic analysis. Neuroscience 2011; 176:349-80. [DOI: 10.1016/j.neuroscience.2010.12.043] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 12/09/2010] [Indexed: 11/15/2022]
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20
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El Ghazi I, Martin BL, Armitage IM. New proteins found interacting with brain metallothionein-3 are linked to secretion. Int J Alzheimers Dis 2010; 2011:208634. [PMID: 21234102 PMCID: PMC3014675 DOI: 10.4061/2011/208634] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 10/19/2010] [Accepted: 11/05/2010] [Indexed: 11/20/2022] Open
Abstract
Metallothionein 3 (MT-3), also known as growth inhibitory factor (GIF), exhibits a neuroinhibitory activity. Our lab and others have previously shown that this biological activity involves interacting protein partners in the brain. However, nothing specific is yet known about which of these interactions is responsible for the GIF activity. In this paper, we are reporting upon new proteins found interacting with MT-3 as determined through immunoaffinity chromatography and mass spectrometry. These new partner proteins-Exo84p, 14-3-3 Zeta, α and β Enolase, Aldolase C, Malate dehydrogenase, ATP synthase, and Pyruvate kinase-along with those previously identified have now been classified into three functional groups: transport and signaling, chaperoning and scaffolding, and glycolytic metabolism. When viewed together, these interactions support a proposed model for the regulation of the GIF activity of MT-3.
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Affiliation(s)
- Issam El Ghazi
- Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, USA
| | - Bruce L. Martin
- Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, USA
| | - Ian M. Armitage
- Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, USA
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21
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Xiong XD, Chen GH. Research progress on the age-related changes in proteins of the synaptic active zone. Physiol Behav 2010; 101:1-12. [PMID: 20433861 DOI: 10.1016/j.physbeh.2010.04.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/15/2010] [Accepted: 04/16/2010] [Indexed: 01/21/2023]
Abstract
Neurotransmitter release during synaptic transmission is mediated by the presynaptic active zone. Multiple protein components at the active zone region interact to regulate docking, priming and fusion of the synaptic vesicles with the presynaptic membrane to maintain normal neurotransmitter release. This review discusses research progress in questions of protein transcript and expression pattern changes at the synaptic active zone related to aging and whether these changes have the effects on learning and memory. We will specifically address normal synaptic structure and proteins; active zone structure and components; active zone functional regulation and age-related changes in active zone proteins.
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Affiliation(s)
- Xiang-Dong Xiong
- People's Hospital of Lu'an City (The Fifth Clinical College of Anhui Medical University), Lu'an City 237005, Anhui Province, PR China.
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22
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Acute in vivo genetic rescue demonstrates that phosphorylation of RIM1alpha serine 413 is not required for mossy fiber long-term potentiation. J Neurosci 2010; 30:2542-6. [PMID: 20164339 DOI: 10.1523/jneurosci.4285-09.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
While presynaptic, protein kinase A (PKA)-dependent, long-term plasticity has been described in numerous brain regions, the target(s) of PKA and the molecular mechanisms leading to sustained changes in neurotransmitter release remain elusive. Here, we acutely reconstitute mossy fiber long-term potentiation (mfLTP) de novo in the mature brains of mutant mice that normally lack this form of plasticity. These results demonstrate that RIM1alpha, a presynaptic scaffold protein and a potential PKA target, can support mfLTP independent of a role in brain development. Using this approach, we study two mutations of RIM1alpha (S413A and V415P) and conclude that PKA-phosphorylation-dependent signaling by RIM1alpha serine 413 is not required for mfLTP, consistent with conclusions reached from the study of RIM1alpha S413A knockin mice. Together, these results provide insights into the mechanism of mossy fiber LTP and demonstrate a useful acute approach to genetically manipulate mossy fiber synapses in the mature brain.
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23
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Wong FK, Stanley EF. Rab3a interacting molecule (RIM) and the tethering of pre-synaptic transmitter release site-associated CaV2.2 calcium channels. J Neurochem 2010; 112:463-73. [DOI: 10.1111/j.1471-4159.2009.06466.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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24
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A protein interaction node at the neurotransmitter release site: domains of Aczonin/Piccolo, Bassoon, CAST, and rim converge on the N-terminal domain of Munc13-1. J Neurosci 2009; 29:12584-96. [PMID: 19812333 DOI: 10.1523/jneurosci.1255-09.2009] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Multidomain scaffolding proteins organize the molecular machinery of neurotransmitter vesicle dynamics during synaptogenesis and synaptic activity. We find that domains of five active zone proteins converge on an interaction node that centers on the N-terminal region of Munc13-1 and includes the zinc-finger domain of Rim1, the C-terminal region of Bassoon, a segment of CAST1/ELKS2, and the third coiled-coil domain (CC3) of either Aczonin/Piccolo or Bassoon. This multidomain complex may constitute a center for the physical and functional integration of the protein machinery at the active zone. An additional connection between Aczonin and Bassoon is mediated by the second coiled-coil domain of Aczonin. Recombinant Aczonin-CC3, expressed in cultured neurons as a green fluorescent protein fusion protein, is targeted to synapses and suppresses vesicle turnover, suggesting involvements in synaptic assembly as well as activity. Our findings show that Aczonin, Bassoon, CAST1, Munc13, and Rim are closely and multiply interconnected, they indicate that Aczonin-CC3 can actively participate in neurotransmitter vesicle dynamics, and they highlight the N-terminal region of Munc13-1 as a hub of protein interactions by adding three new binding partners to its mechanistic potential in the control of synaptic vesicle priming.
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25
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RIM1alpha and RIM1beta are synthesized from distinct promoters of the RIM1 gene to mediate differential but overlapping synaptic functions. J Neurosci 2009; 28:13435-47. [PMID: 19074017 DOI: 10.1523/jneurosci.3235-08.2008] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
At a synapse, presynaptic terminals form a specialized area of the plasma membrane called the active zone that mediates neurotransmitter release. RIM1alpha is a multidomain protein that constitutes a central component of the active zone by binding to other active zone proteins such as Munc13 s, alpha-liprins, and ELKS, and to synaptic vesicle proteins such as Rab3 and synaptotagmin-1. In mice, knockout of RIM1alpha significantly impairs synaptic vesicle priming and presynaptic long-term plasticity, but is not lethal. We now find that the RIM1 gene encodes a second, previously unknown RIM1 isoform called RIM1beta that is upregulated in RIM1alpha knock-out mice. RIM1beta is identical to RIM1alpha except for the N terminus where RIM1beta lacks the N-terminal Rab3-binding sequence of RIM1alpha. Using newly generated knock-out mice lacking both RIM1alpha and RIM1beta, we demonstrate that different from the deletion of only RIM1alpha, deletion of both RIM1alpha and RIM1beta severely impairs mouse survival. Electrophysiological analyses show that the RIM1alphabeta deletion abolishes long-term presynaptic plasticity, as does RIM1alpha deletion alone. In contrast, the impairment in synaptic strength and short-term synaptic plasticity that is caused by the RIM1alpha deletion is aggravated by the deletion of both RIM1alpha and RIM1beta. Thus, our data indicate that the RIM1 gene encodes two different isoforms that perform overlapping but distinct functions in neurotransmitter release.
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26
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Weidenhofer J, Scott RJ, Tooney PA. Investigation of the expression of genes affecting cytomatrix active zone function in the amygdala in schizophrenia: effects of antipsychotic drugs. J Psychiatr Res 2009; 43:282-90. [PMID: 18490030 DOI: 10.1016/j.jpsychires.2008.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 04/02/2008] [Accepted: 04/02/2008] [Indexed: 11/18/2022]
Abstract
The cytomatrix active zone (CAZ) is a specialized cellular structure regulating release of vesicles. We reported previously increased expression of three CAZ genes, piccolo, RIMS2 and RIMS3 in the amygdala in schizophrenia. This study determined the levels of gene and protein expression for components of the active zone including two additional CAZ genes in the amygdala from subjects with schizophrenia and non-psychiatric controls, as well as the effects of antipsychotic drugs. Whilst relative real-time PCR analysis did not identify significant change in the expression of six additional active zone genes, Western blot analysis showed increased piccolo and RIMS2 protein expression in the amygdala in schizophrenia. In vitro analysis suggests antipsychotic drug treatment was unlikely to have caused the changes in RIMS2, RIMS3 and piccolo expression observed in the amygdala in schizophrenia. Therefore, this study provides further evidence suggesting that piccolo, RIMS2, RIMS3, but not the entire components of the active zone are involved in the neurobiology of schizophrenia.
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Affiliation(s)
- Judith Weidenhofer
- School of Biomedical Sciences, Faculty of Health, University of Newcastle, NSW 2308, Australia
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27
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Resolving sub-synaptic compartments with double immunofluorescence labeling in hippocampal neurons. J Neurosci Methods 2009; 176:78-84. [DOI: 10.1016/j.jneumeth.2008.08.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 08/18/2008] [Accepted: 08/18/2008] [Indexed: 11/19/2022]
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28
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RIM1alpha phosphorylation at serine-413 by protein kinase A is not required for presynaptic long-term plasticity or learning. Proc Natl Acad Sci U S A 2008; 105:14680-5. [PMID: 18799741 DOI: 10.1073/pnas.0806679105] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Activation of presynaptic cAMP-dependent protein kinase A (PKA) triggers presynaptic long-term plasticity in synapses such as cerebellar parallel fiber and hippocampal mossy fiber synapses. RIM1alpha, a large multidomain protein that forms a scaffold at the presynaptic active zone, is essential for presynaptic long-term plasticity in these synapses and is phosphorylated by PKA at serine-413. Previous studies suggested that phosphorylation of RIM1alpha at serine-413 is required for presynaptic long-term potentiation in parallel fiber synapses formed in vitro by cultured cerebellar neurons and that this type of presynaptic long-term potentiation is mediated by binding of 14-3-3 proteins to phosphorylated serine-413. To test the role of serine-413 phosphorylation in vivo, we have now produced knockin mice in which serine-413 is mutated to alanine. Surprisingly, we find that in these mutant mice, three different forms of presynaptic PKA-dependent long-term plasticity are normal. Furthermore, we observed that in contrast to RIM1alpha KO mice, RIM1 knockin mice containing the serine-413 substitution exhibit normal learning capabilities. The lack of an effect of the serine-413 mutation of RIM1alpha is not due to compensation by RIM2alpha because mice carrying both the serine-413 substitution and a RIM2alpha deletion still exhibited normal long-term presynaptic plasticity. Thus, phosphorylation of serine-413 of RIM1alpha is not essential for PKA-dependent long-term presynaptic plasticity in vivo, suggesting that PKA operates by a different mechanism despite the dependence of long-term presynaptic plasticity on RIM1alpha.
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29
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Simsek-Duran F, Lonart G. The role of RIM1alpha in BDNF-enhanced glutamate release. Neuropharmacology 2008; 55:27-34. [PMID: 18499195 DOI: 10.1016/j.neuropharm.2008.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Revised: 03/14/2008] [Accepted: 04/11/2008] [Indexed: 11/30/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is known to activate proline-directed Ser/Thr protein kinases and to enhance glutamatergic transmission via a Rab3a-dependent molecular pathway. The identity of molecular targets in BDNF's action on Rab3a pathway, a synaptic vesicle protein involved in vesicle trafficking and synaptic plasticity, is not fully known. Here we demonstrate that BDNF enhances depolarization-evoked efflux of [(3)H]-glutamate from nerve terminals isolated from the CA1 region of the hippocampus. BDNF also potentiated hyperosmotic shock-evoked [(3)H]-glutamate efflux, indicating an effect on the size of the readily releasable pool. This effect of BDNF was completely abolished in nerve terminals derived from Rim1alphaKO (Rab3 interacting molecule 1alpha null mutant) mice. Using in vitro phosphorylation assays we identified two novel phosphorylation sites, Ser447 and Ser745 that were substrates for ERK2, a proline-directed kinase known to be activated by BDNF. The pSer447 site was phosphorylated under resting conditions in hippocampal CA1 nerve terminals and its phosphorylation was enhanced by BDNF treatment, as indicated by the use of a pSer447-RIM1alpha antibody we have developed. Together these findings identify RIM1alpha, a component of the Rab3a molecular pathway in mediating presynaptic plasticity, as a necessary factor in BDNF's enhancement of [(3)H]-glutamate efflux from hippocampal CA1 nerve terminals and indicate a possible role for RIM1alpha phosphorylation in BDNF-dependent presynaptic plasticity.
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Affiliation(s)
- Fatma Simsek-Duran
- Department of Pathology and Anatomy, Eastern Virginia Medical School, 700 W. Olney Road Norfolk, VA 23507, USA
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30
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Liu S, Fa M, Ninan I, Trinchese F, Dauer W, Arancio O. Alpha-synuclein involvement in hippocampal synaptic plasticity: role of NO, cGMP, cGK and CaMKII. Eur J Neurosci 2007; 25:3583-96. [PMID: 17610578 DOI: 10.1111/j.1460-9568.2007.05569.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synaptic plasticity involves a series of coordinate changes occurring both pre- and postsynaptically, of which alpha-synuclein is an integral part. We have investigated on mouse primary hippocampal neurons in culture whether redistribution of alpha-synuclein during plasticity involves retrograde signaling activation through nitric oxide (NO), cGMP, cGMP-dependent protein kinase (cGK) and calmodulin-dependent protein kinase II. We have found that deletion of the alpha-synuclein gene blocks both the long-lasting enhancement of evoked and miniature transmitter release and the increase in the number of functional presynaptic boutons evoked through the NO donor, DEA/NO, and the cGMP analog, 8-Br-cGMP. In agreement with these findings both DEA/NO and 8-Br-cGMP were capable of producing a long-lasting increase in number of clusters for alpha-synuclein through activation of soluble guanylyl cyclase, cGK and calcium/calmodulin-dependent protein kinase IIalpha. Thus, our results suggest that NO, cGMP, GMP-dependent protein kinase and calmodulin-dependent protein kinase II play a key role in the redistribution of alpha-synuclein during plasticity.
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Affiliation(s)
- Shumin Liu
- Department of Pathology, Taub Institute, Columbia University, New York, NY 10032, USA
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31
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Abstract
A major goal of learning and memory research is to correlate the function of molecules with the behaviour of organisms. The beautiful laminar structure of the cerebellar cortex lends itself to the study of synaptic plasticity, because its clearly defined patterns of neurons and their synapses form circuits that have been implicated in simple motor behaviour paradigms. The best understood in terms of molecular mechanism is the parallel fibre-Purkinje cell synapse, where presynaptic long-term potentiation and postsynaptic long-term depression and potentiation finely tune cerebellar output. Our understanding of these forms of plasticity has mostly come from the electrophysiological and behavioural analysis of knockout mutant mice, but more recently the knock-in of synaptic molecules with mutated phosphorylation sites and binding domains has provided more detailed insights into the signalling events. The present review details the major forms of plasticity in the cerebellar cortex, with particular attention to the membrane trafficking and intracellular signalling responsible. This overview of the current literature suggests it will not be long before the involvement of the cerebellum in certain motor behaviours is fully explained in molecular terms.
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Affiliation(s)
- Gareth J O Evans
- Department of Biology (Area 3), University of York, Heslington, York, UK.
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32
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Cecconi D, Mion S, Astner H, Domenici E, Righetti PG, Carboni L. Proteomic analysis of rat cortical neurons after fluoxetine treatment. Brain Res 2007; 1135:41-51. [PMID: 17196950 DOI: 10.1016/j.brainres.2006.12.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 11/27/2006] [Accepted: 12/04/2006] [Indexed: 12/27/2022]
Abstract
The known neurochemical effect of most currently available antidepressants is the enhancement of the synaptic levels of monoamine neurotransmitters. However, the existence of other mechanisms has been suggested to justify the significant delay between the modulation of the monoaminergic system and the clinical effects. In order to investigate the effects of the antidepressant fluoxetine (a prototypical serotonin selective re-uptake inhibitor) and to improve the understanding of its mechanism of action, we performed a proteomic investigation in rat primary cortical neurons exposed sub-chronically to this antidepressant. Cortical neurons were treated for 3 days with 1 microM fluoxetine or vehicle. Protein extracts were processed for 2D gel characterization. Image analysis allowed the identification of six proteins differently expressed by more than 100% and seven proteins differently expressed by more than 50% (P<0.05). Nine proteins were identified by mass spectrometry. Among them, cyclophilin A, 14-3-3 protein z/delta and GRP78 are involved in neuroprotection, in serotonin biosynthesis and in axonal transport, respectively. This study showed that the primary culture of cortical neurons is a suitable system for studying the effects of fluoxetine action and may contribute to improve the understanding of fluoxetine psychotherapeutic action and the mechanisms mediating the long-term effects of this antidepressant treatment.
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Affiliation(s)
- Daniela Cecconi
- Department of Agricultural and Industrial Biotechnologies, University of Verona, Italy
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33
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Sun L, Stoecklin G, Van Way S, Hinkovska-Galcheva V, Guo RF, Anderson P, Shanley TP. Tristetraprolin (TTP)-14-3-3 complex formation protects TTP from dephosphorylation by protein phosphatase 2a and stabilizes tumor necrosis factor-alpha mRNA. J Biol Chem 2006; 282:3766-77. [PMID: 17170118 DOI: 10.1074/jbc.m607347200] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tumor necrosis factor (TNF)-alpha is a major cytokine produced by alveolar macrophages in response to pathogen-associated molecular patterns such as lipopolysaccharide. TNF-alpha secretion is regulated at both transcriptional and post-transcriptional levels. Post-transcriptional regulation occurs by modulation of TNF-alpha mRNA stability via the binding of tristetraprolin (TTP) to the adenosine/uridine-rich elements found in the 3'-untranslated region of the TNF-alpha transcript. Phosphorylation plays important roles in modulating mRNA stability, because activation of p38 MAPK by lipopolysaccharide stabilizes TNF-alpha mRNA. We hypothesized that the protein phosphatase 2A (PP2A) regulates this signaling pathway. Our results show that inhibition of PP2A by okadaic acid or small interference RNA significantly enhanced the stability of TNF-alpha mRNA. This result was associated with increased phosphorylation of p38 MAPK and MAPK-activated kinase 2 (MK-2). PP2A inhibition increased TTP phosphorylation and enhanced complex formation with chaperone protein 14-3-3. TTP physically interacted with PP2A in transfected mammalian cells. A functional consequence of TTP-14-3-3 complex formation appeared to be protection of TTP from dephosphorylation by inhibition of the binding of PP2A to phosphorylated TTP. Mutation of the MK-2 phosphorylation sites of TTP did not influence TNF-alpha adenosine/uridine-rich element binding and did not alter the increased TNF-alpha 3'-untranslated region-dependent luciferase activity induced by PP2A-small interference RNA silencing. Our data indicate that, although phosphorylation stabilizes TNF-alpha mRNA, PP2A regulates the mRNA stability by modulating the phosphorylation state of members of the p38/MK-2/TTP pathway.
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Affiliation(s)
- Lei Sun
- Division of Critical Care, Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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34
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Schoch S, Mittelstaedt T, Kaeser PS, Padgett D, Feldmann N, Chevaleyre V, Castillo PE, Hammer RE, Han W, Schmitz F, Lin W, Südhof TC. Redundant functions of RIM1alpha and RIM2alpha in Ca(2+)-triggered neurotransmitter release. EMBO J 2006; 25:5852-63. [PMID: 17124501 PMCID: PMC1698877 DOI: 10.1038/sj.emboj.7601425] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 10/13/2006] [Indexed: 11/08/2022] Open
Abstract
Alpha-RIMs (RIM1alpha and RIM2alpha) are multidomain active zone proteins of presynaptic terminals. Alpha-RIMs bind to Rab3 on synaptic vesicles and to Munc13 on the active zone via their N-terminal region, and interact with other synaptic proteins via their central and C-terminal regions. Although RIM1alpha has been well characterized, nothing is known about the function of RIM2alpha. We now show that RIM1alpha and RIM2alpha are expressed in overlapping but distinct patterns throughout the brain. To examine and compare their functions, we generated knockout mice lacking RIM2alpha, and crossed them with previously produced RIM1alpha knockout mice. We found that deletion of either RIM1alpha or RIM2alpha is not lethal, but ablation of both alpha-RIMs causes postnatal death. This lethality is not due to a loss of synapse structure or a developmental change, but to a defect in neurotransmitter release. Synapses without alpha-RIMs still contain active zones and release neurotransmitters, but are unable to mediate normal Ca(2+)-triggered release. Our data thus demonstrate that alpha-RIMs are not essential for synapse formation or synaptic exocytosis, but are required for normal Ca(2+)-triggering of exocytosis.
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Affiliation(s)
- Susanne Schoch
- Emmy Noether Research Group, Institute of Neuropathology, Department of Epileptology, University Bonn, Sigmund Freud Strasse 25, 53105 Bonn, Germany.
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35
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Chaithirayanon K, Grams R, Vichasri-Grams S, Hofmann A, Korge G, Viyanant V, Upatham ES, Sobhon P. Molecular and immunological characterization of encoding gene and 14-3-3 protein 1 in Fasciola gigantica. Parasitology 2006; 133:763-75. [PMID: 16938151 DOI: 10.1017/s0031182006001119] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 06/15/2006] [Accepted: 06/15/2006] [Indexed: 11/06/2022]
Abstract
A cDNA encoding Fg14-3-3 protein 1 was cloned by immunoscreening of an adult-stage Fasciola gigantica cDNA library using a rabbit antiserum against tegumental antigens of the parasite. The protein has a deduced amino acid sequence of 252 residues and a calculated molecular weight of 28.7 kDa. It shows sequence identity values between 57.6 and 58.1% to the human 14-3-3 beta, zeta, theta, and eta proteins and is in a phylogenetic cluster with the 14-3-3 protein 1 of Schistosoma spp. Nucleic acid analyses indicate that the Fg14-3-3 protein 1 is encoded by a single copy gene and that this gene is expressed as a transcript of 1250 nucleotides. In adult and 4-week-old parasites the gene's transcriptional and translational products were localized in the gut epithelium, parenchyma, tegument cells, and in the reproductive organs. An antiserum against recombinant Fg14-3-3 protein 1 detected a slightly smaller 14-3-3 protein in the parasite's excretion/secretion material and showed cross-reactivity with 14-3-3 proteins in extracts of other trematodes and mouse. Antibodies against Fg14-3-3 protein were detected in the sera of rabbits as early as 2 weeks after infection with metacercariae of F. gigantica and the antibody titre increased continuously over a 10-week observation period.
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MESH Headings
- 14-3-3 Proteins/chemistry
- 14-3-3 Proteins/genetics
- 14-3-3 Proteins/immunology
- Amino Acid Sequence
- Animals
- Antibodies, Helminth/blood
- Antibodies, Helminth/immunology
- Antigens, Helminth/chemistry
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Cloning, Molecular
- Fasciola/genetics
- Fasciola/growth & development
- Fasciola/immunology
- Fasciola/metabolism
- Fascioliasis/immunology
- Female
- Gene Library
- Male
- Mice
- Molecular Sequence Data
- Organ Specificity
- RNA, Helminth/genetics
- RNA, Helminth/isolation & purification
- RNA, Helminth/metabolism
- Rabbits
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Sequence Analysis, DNA
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Affiliation(s)
- K Chaithirayanon
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok, 10400, Thailand
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Schoch S, Gundelfinger ED. Molecular organization of the presynaptic active zone. Cell Tissue Res 2006; 326:379-91. [PMID: 16865347 DOI: 10.1007/s00441-006-0244-y] [Citation(s) in RCA: 223] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 05/10/2006] [Indexed: 11/26/2022]
Abstract
The exocytosis of neurotransmitter-filled synaptic vesicles is under tight temporal and spatial control in presynaptic nerve terminals. The fusion of synaptic vesicles is restricted to a specialized area of the presynaptic plasma membrane: the active zone. The protein network that constitutes the cytomatrix at the active zone (CAZ) is involved in the organization of docking and priming of synaptic vesicles and in mediating use-dependent changes in release during short-term and long-term synaptic plasticity. To date, five protein families whose members are highly enriched at active zones (Munc13s, RIMs, ELKS proteins, Piccolo and Bassoon, and the liprins-alpha), have been characterized. These multidomain proteins are instrumental for the diverse functions performed by the presynaptic active zone.
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Affiliation(s)
- Susanne Schoch
- Emmy Noether Research Group, Institute of Neuropathology and Department of Epileptology, University of Bonn Medical Center, Sigmund Freud Strasse 25, 53105 Bonn, Germany.
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37
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Michaelides M, Hardcastle AJ, Hunt DM, Moore AT. Progressive cone and cone-rod dystrophies: phenotypes and underlying molecular genetic basis. Surv Ophthalmol 2006; 51:232-58. [PMID: 16644365 DOI: 10.1016/j.survophthal.2006.02.007] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The cone and cone-rod dystrophies form part of a heterogeneous group of retinal disorders that are an important cause of visual impairment in children and adults. There have been considerable advances made in recent years in our understanding of the pathogenesis of these retinal dystrophies, with many of the chromosomal loci and causative genes having now been identified. Mutations in 12 genes, including GUCA1A, peripherin/RDS, ABCA4 and RPGR, have been described to date; and in many cases detailed functional assessment of the effects of the encoded mutant proteins has been undertaken. This improved knowledge of disease mechanisms has raised the possibility of future treatments for these disorders, for which there are no specific therapies available at the present time.
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38
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Weidenhofer J, Bowden NA, Scott RJ, Tooney PA. Altered gene expression in the amygdala in schizophrenia: Up-regulation of genes located in the cytomatrix active zone. Mol Cell Neurosci 2006; 31:243-50. [PMID: 16236523 DOI: 10.1016/j.mcn.2005.09.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 08/26/2005] [Accepted: 09/15/2005] [Indexed: 11/25/2022] Open
Abstract
The amygdala is implicated in the pathophysiology of schizophrenia through its function in the processing of emotions. However, the genes involved in the dysfunction of the amygdala in schizophrenia are yet to be identified. This study examined gene expression in the amygdala in postmortem tissue from seven matched pairs of schizophrenia and non-psychiatric control subjects, using oligonucleotide-microarrays representing 19,000 gene transcripts and real-time PCR confirmation of gene expression changes in eleven matched pairs. Genes involved in presynaptic function, myelination and cellular signalling were identified as being consistently dysregulated in this cohort of subjects with schizophrenia. In particular, the expression of three genes involved in the cytomatrix active zone, Regulating membrane exocytosis 2, Regulating membrane exocytosis 3 and Piccolo, was up-regulated. These results implicate for the first time the dysfunction of the cytomatrix active zone of synapses in the amygdala in the pathophysiology of schizophrenia.
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Affiliation(s)
- Judith Weidenhofer
- Neuroscience Institute of Schizophrenia and Allied Disorders (NISAD), NSW, Australia
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39
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Abstract
RIM1alpha (Rab3-interacting molecule 1alpha) is a large multidomain protein that is localized to presynaptic active zones [Wang, Okamoto, Schmitz, Hofmann and Südhof (1997) Nature (London) 388, 593-598] and is the founding member of the RIM protein family that also includes RIM2alpha, 2beta, 2gamma, 3gamma and 4gamma [Wang and Südhof (2003) Genomics 81, 126-137]. In presynaptic nerve termini, RIM1alpha interacts with a series of presynaptic proteins, including the synaptic vesicle GTPase Rab3 and the active zone proteins Munc13, liprins and ELKS (a protein rich in glutamate, leucine, lysine and serine). Mouse KOs (knockouts) revealed that, in different types of synapses, RIM1alpha is essential for different forms of synaptic plasticity. In CA1-region Schaffer-collateral excitatory synapses and in GABAergic synapses (where GABA is gamma-aminobutyric acid), RIM1alpha is required for maintaining normal neurotransmitter release and short-term synaptic plasticity. In contrast, in excitatory CA3-region mossy fibre synapses and cerebellar parallel fibre synapses, RIM1alpha is necessary for presynaptic long-term, but not short-term, synaptic plasticity. In these synapses, the function of RIM1alpha in presynaptic long-term plasticity depends, at least in part, on phosphorylation of RIM1alpha at a single site, suggesting that RIM1alpha constitutes a 'phosphoswitch' that determines synaptic strength. However, in spite of the progress in understanding RIM1alpha function, the mechanisms by which RIM1alpha acts remain unknown. For example, how does phosphorylation regulate RIM1alpha, what is the relationship of the function of RIM1alpha in basic release to synaptic plasticity and what is the physiological significance of different forms of RIM-dependent plasticity? Moreover, the roles of other RIM isoforms are unclear. Addressing these important questions will contribute to our view of how neurotransmitter release is regulated at the presynaptic active zone.
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40
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Powell CM. Gene targeting of presynaptic proteins in synaptic plasticity and memory: across the great divide. Neurobiol Learn Mem 2005; 85:2-15. [PMID: 16230036 PMCID: PMC3910109 DOI: 10.1016/j.nlm.2005.08.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 08/09/2005] [Accepted: 08/11/2005] [Indexed: 12/21/2022]
Abstract
The past few decades have seen an explosion in our understanding of the molecular basis of learning and memory. The majority of these studies in mammals focused on post-synaptic signal transduction cascades involved in post-synaptic long-lasting plasticity. Until recently, relatively little work examined the role of presynaptic proteins in learning and memory in complex systems. The synaptic cleft figuratively represents a "great divide" between our knowledge of post- versus presynaptic involvement in learning and memory. While great strides have been made in our understanding of presynaptic proteins, we know very little of how presynaptically expressed forms of short- and long-term plasticity participate in information processing and storage. The paucity of cognitive behavioral research in the area of presynaptic proteins, however, is in stark contrast to the plethora of information concerning presynaptic protein involvement in neurotransmitter release, in modulation of release, and in both short- and long-term forms of presynaptic plasticity. It is now of great interest to begin to link the extensive literature on presynaptic proteins and presynaptic plasticity to cognitive behavior. In the future there is great promise with these approaches for identifying new targets in the treatment of cognitive disorders. This review article briefly surveys current knowledge on the role of presynaptic proteins in learning and memory in mammals and suggests future directions in learning and memory research on the presynaptic rim of the "great divide."
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Affiliation(s)
- Craig M Powell
- Department of Neurology, The University of Texas, Southwestern Medical Center, Dallas, TX 75225, USA.
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41
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Barclay JW, Morgan A, Burgoyne RD. Calcium-dependent regulation of exocytosis. Cell Calcium 2005; 38:343-53. [PMID: 16099500 DOI: 10.1016/j.ceca.2005.06.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 11/30/2022]
Abstract
A rapid increase in intracellular calcium directly triggers regulated exocytosis. In addition, changes in intracellular calcium concentration can adjust the extent of exocytosis (quantal content) or the magnitude of individual release events (quantal size) in both the short- and long-term. It is generally agreed that calcium achieves this regulation via an interaction with a number of different molecular targets located at or near to the site of membrane fusion. We review here the synaptic proteins with defined calcium-binding domains and protein kinases activated by calcium, summarize what is known about their function in membrane fusion and the experimental evidence in support of their involvement in synaptic plasticity.
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Affiliation(s)
- Jeff W Barclay
- Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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42
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Nakada-Tsukui K, Saito-Nakano Y, Ali V, Nozaki T. A retromerlike complex is a novel Rab7 effector that is involved in the transport of the virulence factor cysteine protease in the enteric protozoan parasite Entamoeba histolytica. Mol Biol Cell 2005; 16:5294-303. [PMID: 16120649 PMCID: PMC1266427 DOI: 10.1091/mbc.e05-04-0283] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vesicular trafficking plays an important role in a virulence mechanism of the enteric protozoan parasite Entamoeba histolytica as secreted and lysosomal cysteine protease (CP) contributes to both cytolysis of tissues and degradation of internalized host cells. Despite the primary importance of intracellular sorting in pathogenesis, the molecular mechanism of CP trafficking remains largely unknown. In this report we demonstrate that transport of CP is regulated through a specific interaction of Rab7A small GTPase (EhRab7A) with the retromerlike complex. The amoebic retromerlike complex composed of Vps26, Vps29, and Vps35 was identified as EhRab7A-binding proteins. The amoebic retromerlike complex specifically bound to GTP-EhRab7A, but not GDP-EhRab7A through the direct binding via the carboxy terminus of EhVps26. In erythrophagocytosis the retromerlike complex was recruited to prephagosomal vacuoles, the unique preparatory vacuole of digestive enzymes, and later to phagosomes. This dynamism was indistinguishable from that of EhRab7A, and consistent with the premise that the retromerlike complex is involved in the retrograde transport of putative hydrolase receptor(s) from preparatory vacuoles and phagosomes to the Golgi apparatus. EhRab7A overexpression caused enlargement of lysosomes and decrease of the cellular CP activity. The reduced CP activity was restored by the coexpression of EhVps26, implying that the EhRab7A-mediated transport of CP to phagosomes is regulated by the retromerlike complex.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
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43
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Steinacker P, Schwarz P, Reim K, Brechlin P, Jahn O, Kratzin H, Aitken A, Wiltfang J, Aguzzi A, Bahn E, Baxter HC, Brose N, Otto M. Unchanged survival rates of 14-3-3gamma knockout mice after inoculation with pathological prion protein. Mol Cell Biol 2005; 25:1339-46. [PMID: 15684385 PMCID: PMC547999 DOI: 10.1128/mcb.25.4.1339-1346.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) is based on typical clinical findings and is supported by a positive 14-3-3 Western blot of cerebrospinal fluid. However, it is not clear whether 14-3-3 indicates general neuronal damage or is of pathophysiological relevance in CJD. The fact that the 14-3-3 isoform spectrum in cerebrospinal fluid does not correspond to that found in the brain points to a regulated process. To investigate a possible role of 14-3-3 proteins in transmissible spongiform diseases, we generated a 14-3-3gamma-deficient mutant mouse line by using a classical knockout strategy. The anatomy and cage behavior of the mutant mice were normal. Western blot analyses of brain homogenates revealed no changes in the protein expression of other 14-3-3 isoforms (epsilon, beta, zeta, and eta). Proteomic analyses of mouse brains by two-dimensional differential gel electrophoresis showed that several proteins, including growth hormone, 1-Cys peroxiredoxin, CCT-zeta, glucose-6-phosphate isomerase, GRP170 precursor, and alpha-SNAP, were differentially expressed. Mutant and wild-type mice were inoculated either intracerebrally or intraperitoneally with the Rocky Mountain Laboratory strain of scrapie, but no differences were detected in the postinoculation survival rates. These results indicate that 14-3-3gamma is unlikely to play a causal role in CJD and related diseases.
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Affiliation(s)
- Petra Steinacker
- Neurologische Klinik und Poliklinik, Georg-August-Universität Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
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44
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Michaelides M, Holder GE, Hunt DM, Fitzke FW, Bird AC, Moore AT. A detailed study of the phenotype of an autosomal dominant cone-rod dystrophy (CORD7) associated with mutation in the gene for RIM1. Br J Ophthalmol 2005; 89:198-206. [PMID: 15665353 PMCID: PMC1772528 DOI: 10.1136/bjo.2004.050773] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To characterise the phenotype of an autosomal dominant cone-rod dystrophy (CORD7) associated with the Arg844His mutation in RIM1. METHODS Eight members of a four generation, non-consanguineous British family were examined clinically and underwent electrophysiological testing, automated dark adapted perimetry, dark adaptometry, colour vision assessment, colour fundus photography, fundus fluorescein angiography (FFA), and fundus autofluorescence (AF) imaging. RESULTS The majority of affected individuals described a progressive deterioration of central vision, night vision, and peripheral visual field usually between the third and fourth decades. The visual acuity ranged from 6/6 to 3/60. Colour vision testing showed mild to moderate dyschromatopsia in the majority of individuals. Fundus changes comprised a range of macular appearances varying from mild retinal pigment epithelial (RPE) disturbance to extensive atrophy and pigmentation. In some individuals retinal vessels were attenuated and in two subjects peripheral areas of retinal atrophy were present. An absent or severely reduced PERG was detected in all subjects, indicative of marked macular dysfunction. Full field ERG showed abnormal rod and cone responses. AF imaging revealed decreased macular AF centrally surrounded by a ring of increased AF in the majority of individuals. "Bull's eye" lesions were present in two individuals, comprising of a ring of decreased perifoveal AF bordered peripherally and centrally by increased AF. Photopic sensitivity testing demonstrated elevated central visual field thresholds with additional superior greater than inferior peripheral field loss. There were rod and cone sensitivity reductions in the central and peripheral visual fields, with the inferior retina being more affected than the superior. CONCLUSIONS The detailed phenotype is described of the autosomal dominant cone-rod dystrophy, CORD7, which is associated with a point mutation in RIM1, a gene encoding a photoreceptor synaptic protein. The pattern of disease progression and long term visual outcome facilitates improved genetic counselling and advice on prognosis. Such phenotypic data will be invaluable in the event of future therapy.
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Affiliation(s)
- M Michaelides
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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45
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Simsek-Duran F, Linden DJ, Lonart G. Adapter protein 14-3-3 is required for a presynaptic form of LTP in the cerebellum. Nat Neurosci 2004; 7:1296-8. [PMID: 15543142 DOI: 10.1038/nn1348] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Accepted: 09/14/2004] [Indexed: 11/09/2022]
Abstract
Long-term potentiation (LTP) of granule cell-Purkinje cell synapses in the mouse cerebellum requires phosphorylation by protein kinase A of the active-zone protein RIM1alpha at Ser413. Here, we show that the adapter protein 14-3-3 readily binds phosphorylated Ser413 in RIM1alpha, and that presynaptic transfection with a dominant-negative 14-3-3eta mutant, or a RIM1alpha mutant with enhanced 14-3-3 binding, inhibits LTP. Thus, RIM1alpha phosphorylation triggers presynaptic LTP in part through recruitment of 14-3-3 to phospho-Ser413-RIM1alpha.
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Affiliation(s)
- Fatma Simsek-Duran
- Department of Pathology & Anatomy, Eastern Virginia Medical School, Norfolk, Virginia 23501, USA
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46
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Fukuda M. Alternative splicing in the first alpha-helical region of the Rab-binding domain of Rim regulates Rab3A binding activity: is Rim a Rab3 effector protein during evolution? Genes Cells 2004; 9:831-42. [PMID: 15330860 DOI: 10.1111/j.1365-2443.2004.00767.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rim1 and Rim2 were originally described as specific Rab3A-effector proteins involved in the regulation of secretory vesicle exocytosis. The putative Rab3A-binding domain (RBD) of Rim consists of two alpha-helical regions (named RBD1 and RBD2) separated by two zinc finger motifs. Although alternative splicing in the RBD1 of Rim is known to produce long and short forms of RBD (named Rim1 and Rim1Delta56-105, and Rim2(+40A) and Rim2, respectively), with the long form of Rim1 and short form of Rim2 being dominant in mouse brain, the physiological significance of the alternative splicing in RBD1 has never been elucidated. In the present study I discovered that alternative splicing in Rim RBD1 alters Rab3A binding affinity to Rims, and found that insertion of 40 amino acids into the RBD1 of Rim2 (i.e. Rim2(+40A)) dramatically reduced its Rab3A binding activity (more than a 50-fold decrease in affinity). Similarly, Rim1Delta56-105 exhibited higher affinity binding to Rab3A than the long form of Rim1. Expression of the short forms of the Rim RBD in PC12 cells co-localized well with endogenous Rab3A, whereas expression of the long forms of the Rim RBD in PC12 cells resulted in cytoplasimc and nuclear localization. Moreover, I found that Caenorhabditis elegans Rim/UNC-10 (ce-Rim) and Drosophila Rim (dm-Rim) do not interact with ce-Rab3 and dm-Rab3, respectively, indicating that the Rab3-effector function of Rim has not been retained during evolution. Based on these findings, I propose that the Rab3A-effector function of Rim during secretory vesicle exocytosis is limited to the short form of the mammalian Rim RBD alone.
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Affiliation(s)
- Mitsunori Fukuda
- Fukuda Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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47
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Thomas DDH, Weng N, Groblewski GE. Secretagogue-induced translocation of CRHSP-28 within an early apical endosomal compartment in acinar cells. Am J Physiol Gastrointest Liver Physiol 2004; 287:G253-63. [PMID: 14977633 DOI: 10.1152/ajpgi.00033.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ca(2+)-regulated heat-stable protein (CRHSP-28) is a member of the TPD52 protein family that has been shown to regulate Ca(2+)-dependent secretory activity in pancreatic acinar cells. Immunofluorescence microscopy of isolated lobules demonstrated that CRHSP-28 is localized to a supranuclear apical compartment in acini and accumulates immediately below the apical membrane within 2 min of CCK octapeptide (CCK-8) stimulation. Dual-immunofluorescence microscopy demonstrated an endosomal localization of CRHSP-28 that strongly overlapped with early endosomal antigen-1 (EEA-1) on vesicular structures throughout the apical cytoplasm but showed only minimal overlap with the transferrin receptor, which is present in basolaterally derived endosomes. Significant overlapping of CRHSP-28 with the trans-Golgi network marker-38 was also noted in supranuclear regions of acini. Interestingly, treatment of lobules with brefeldin A reversibly disrupted the vesicular localization of CRHSP-28 and EEA-1 within the apical cytoplasm. The CCK-8-induced accumulation of CRHSP-28 in subapical regions of acini was not altered by inhibition of apical endocytosis with the actin filament-disrupting agent latrunculin B. Immunoelectron microscopy confirmed that CRHSP-28 is associated with the limiting membrane of irregularly shaped vesicular structures of low electron density in the apical cytoplasm that are positive for EEA-1 staining. Sparse, but significant, CRHSP-28 immunoreactivity was also observed along the limiting membrane of zymogen granules. Consistent with immunofluorescence data, CRHSP-28 was found to accumulate in clusters on endosomes and positioned between zymogen granules below the cell apex on CCK-8 stimulation. These data indicate that CRHSP-28 is present within endocytic and exocytic compartments of acinar cells and is acutely regulated by secretagogue stimulation.
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Affiliation(s)
- Diana D H Thomas
- Department of Nutritional Sciences, University of Wisconsin, 1415 Linden Drive, Madison, WI 53706, USA
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Calakos N, Schoch S, Südhof TC, Malenka RC. Multiple Roles for the Active Zone Protein RIM1α in Late Stages of Neurotransmitter Release. Neuron 2004; 42:889-96. [PMID: 15207234 DOI: 10.1016/j.neuron.2004.05.014] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 04/07/2004] [Accepted: 05/17/2004] [Indexed: 11/26/2022]
Abstract
The active zone protein RIM1alpha interacts with multiple active zone and synaptic vesicle proteins and is implicated in short- and long-term synaptic plasticity, but it is unclear how RIM1alpha's biochemical interactions translate into physiological functions. To address this question, we analyzed synaptic transmission in autaptic neurons cultured from RIM1alpha-/- mice. Deletion of RIM1alpha causes a large reduction in the readily releasable pool of vesicles, alters short-term plasticity, and changes the properties of evoked asynchronous release. Lack of RIM1alpha, however, had no effect on synapse formation, spontaneous release, overall Ca2+ sensitivity of release, or synaptic vesicle recycling. These results suggest that RIM1alpha modulates sequential steps in synaptic vesicle exocytosis through serial protein-protein interactions and that this modulation is the basis for RIM1alpha's role in synaptic plasticity.
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Affiliation(s)
- Nicole Calakos
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA 94304, USA
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