1
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Kleene R, Loers G, Schachner M. The KDET Motif in the Intracellular Domain of the Cell Adhesion Molecule L1 Interacts with Several Nuclear, Cytoplasmic, and Mitochondrial Proteins Essential for Neuronal Functions. Int J Mol Sci 2023; 24:932. [PMID: 36674445 PMCID: PMC9866381 DOI: 10.3390/ijms24020932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023] Open
Abstract
Abnormal functions of the cell adhesion molecule L1 are linked to several neural diseases. Proteolytic L1 fragments were reported to interact with nuclear and mitochondrial proteins to regulate events in the developing and the adult nervous system. Recently, we identified a 55 kDa L1 fragment (L1-55) that interacts with methyl CpG binding protein 2 (MeCP2) and heterochromatin protein 1 (HP1) via the KDET motif. We now show that L1-55 also interacts with histone H1.4 (HistH1e) via this motif. Moreover, we show that this motif binds to NADH dehydrogenase ubiquinone flavoprotein 2 (NDUFV2), splicing factor proline/glutamine-rich (SFPQ), the non-POU domain containing octamer-binding protein (NonO), paraspeckle component 1 (PSPC1), WD-repeat protein 5 (WDR5), heat shock cognate protein 71 kDa (Hsc70), and synaptotagmin 1 (SYT1). Furthermore, applications of HistH1e, NDUFV2, SFPQ, NonO, PSPC1, WDR5, Hsc70, or SYT1 siRNAs or a cell-penetrating KDET-carrying peptide decrease L1-dependent neurite outgrowth and the survival of cultured neurons. These findings indicate that L1's KDET motif binds to an unexpectedly large number of molecules that are essential for nervous system-related functions, such as neurite outgrowth and neuronal survival. In summary, L1 interacts with cytoplasmic, nuclear and mitochondrial proteins to regulate development and, in adults, the formation, maintenance, and flexibility of neural functions.
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Affiliation(s)
- Ralf Kleene
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Gabriele Loers
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience, Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA
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2
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Yang X, Tu W, Gao X, Zhang Q, Guan J, Zhang J. Functional regulation of syntaxin-1: An underlying mechanism mediating exocytosis in neuroendocrine cells. Front Endocrinol (Lausanne) 2023; 14:1096365. [PMID: 36742381 PMCID: PMC9892835 DOI: 10.3389/fendo.2023.1096365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
The fusion of the secretory vesicle with the plasma membrane requires the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein complexes formed by synaptobrevin, syntaxin-1, and SNAP-25. Within the pathway leading to exocytosis, the transitions between the "open" and "closed" conformations of syntaxin-1 function as a switch for the fusion of vesicles with the plasma membranes; rapid assembly and disassembly of syntaxin-1 clusters on the plasma membrane provide docking and fusion sites for secretory vesicles in neuroendocrine cells; and the fully zippered trans-SNARE complex, which requires the orderly, rapid and accurate binding of syntaxin-1 to other SNARE proteins, play key roles in triggering fusion. All of these reactions that affect exocytosis under physiological conditions are tightly regulated by multiple factors. Here, we review the current evidence for the involvement of syntaxin-1 in the mechanism of neuroendocrine cell exocytosis, discuss the roles of multiple factors such as proteins, lipids, protein kinases, drugs, and toxins in SNARE complex-mediated membrane fusion, and present an overview of syntaxin-1 mutation-associated diseases with a view to developing novel mechanistic therapeutic targets for the treatment of neuroendocrine disorders.
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Affiliation(s)
- Xinquan Yang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Weifeng Tu
- Faculty of Anesthesioloy, Suzhou Hospital Affiliated to Medical School of Nanjing University, Suzhou, China
| | - Xuzhu Gao
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Qi Zhang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Jinping Guan
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Junlong Zhang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
- *Correspondence: Junlong Zhang,
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3
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Bajaj R, Rodriguez BL, Russell WK, Warner AN, Diao L, Wang J, Raso MG, Lu W, Khan K, Solis LS, Batra H, Tang X, Fradette JF, Kundu ST, Gibbons DL. Impad1 and Syt11 work in an epistatic pathway that regulates EMT-mediated vesicular trafficking to drive lung cancer invasion and metastasis. Cell Rep 2022; 40:111429. [PMID: 36170810 PMCID: PMC9665355 DOI: 10.1016/j.celrep.2022.111429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 07/10/2022] [Accepted: 09/08/2022] [Indexed: 12/02/2022] Open
Abstract
Lung cancer is a highly aggressive and metastatic disease responsible for approximately 25% of all cancer-related deaths in the United States. Using high-throughput in vitro and in vivo screens, we have previously established Impad1 as a driver of lung cancer invasion and metastasis. Here we elucidate that Impad1 is a direct target of the epithelial microRNAs (miRNAs) miR-200 and miR∼96 and is de-repressed during epithelial-to-mesenchymal transition (EMT); thus, we establish a mode of regulation of the protein. Impad1 modulates Golgi apparatus morphology and vesicular trafficking through its interaction with a trafficking protein, Syt11. These changes in Golgi apparatus dynamics alter the extracellular matrix and the tumor microenvironment (TME) to promote invasion and metastasis. Inhibiting Impad1 or Syt11 disrupts the cancer cell secretome, regulates the TME, and reverses the invasive or metastatic phenotype. This work identifies Impad1 as a regulator of EMT and secretome-mediated changes during lung cancer progression.
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Affiliation(s)
- Rakhee Bajaj
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; UTHealth Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX 77030, USA
| | - B Leticia Rodriguez
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Amanda N Warner
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; UTHealth Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX 77030, USA
| | - Lixia Diao
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jing Wang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Maria G Raso
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Wei Lu
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Khaja Khan
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Luisa S Solis
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Harsh Batra
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Ximing Tang
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Jared F Fradette
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; UTHealth Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX 77030, USA
| | - Samrat T Kundu
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Don L Gibbons
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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4
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Lyons EL, Leone-Kabler S, Kovach AL, Thomas BF, Howlett AC. Cannabinoid receptor subtype influence on neuritogenesis in human SH-SY5Y cells. Mol Cell Neurosci 2020; 109:103566. [PMID: 33049367 DOI: 10.1016/j.mcn.2020.103566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/01/2020] [Accepted: 10/06/2020] [Indexed: 10/23/2022] Open
Abstract
Human SH-SY5Y neuroblastoma cells stably expressing exogenous CB1 (CB1XS) or CB2 (CB2XS) receptors were developed to investigate endocannabinoid signaling in the extension of neuronal projections. Expression of cannabinoid receptors did not alter proliferation rate, viability, or apoptosis relative to parental SH-SY5Y. Transcripts for endogenous cannabinoid system enzymes (diacylglycerol lipase, monoacylglycerol lipase, α/β-hydrolase domain containing proteins 6 and 12, N-acyl phosphatidylethanolamine-phospholipase D, and fatty acid amide hydrolase) were not altered by CB1 or CB2 expression. Endocannabinoid ligands 2-arachidonoylglycerol (2-AG) and anandamide were quantitated in SH-SY5Y cells, and diacylglycerol lipase inhibitor tetrahydrolipstatin decreased 2-AG abundance by 90% but did not alter anandamide abundance. M3 muscarinic agonist oxotremorine M, and inhibitors of monoacylglycerol lipase and α/β hydrolase domain containing proteins 6 &12 increased 2-AG abundance. CB1 receptor expression increased lengths of short (<30 μm) and long (>30 μm) projections, and this effect was significantly reduced by tetrahydrolipstatin, indicative of stimulation by endogenously produced 2-AG. Pertussis toxin, Gβγ inhibitor gallein, and β-arrestin inhibitor barbadin did not significantly alter long projection length in CB1XS, but significantly reduced short projections, with gallein having the greatest inhibition. The rho kinase inhibitor Y27632 increased CB1 receptor-mediated long projection extension, indicative of actin cytoskeleton involvement. CB1 receptor expression increased GAP43 and ST8SIA2 mRNA and decreased ITGA1 mRNA, whereas CB2 receptor expression increased NCAM and SYT mRNA. We propose that basal endogenous production of 2-AG provides autocrine stimulation of CB1 receptor signaling through Gi/o, Gβγ, and β-arrestin mechanisms to promote neuritogenesis, and rho kinase influences process extension.
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Affiliation(s)
- Erica L Lyons
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
| | - Sandra Leone-Kabler
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
| | - Alexander L Kovach
- Discovery Sciences, RTI International, PO Box 12194, Research Triangle Park, NC 27709, USA.
| | - Brian F Thomas
- Discovery Sciences, RTI International, PO Box 12194, Research Triangle Park, NC 27709, USA.
| | - Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, One Medical Center Blvd., Winston-Salem, NC 27157, USA.
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5
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Minini M, Senni A, Unfer V, Bizzarri M. The Key Role of IP 6K: A Novel Target for Anticancer Treatments? Molecules 2020; 25:molecules25194401. [PMID: 32992691 PMCID: PMC7583815 DOI: 10.3390/molecules25194401] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 12/29/2022] Open
Abstract
Inositol and its phosphate metabolites play a pivotal role in several biochemical pathways and gene expression regulation: inositol pyrophosphates (PP-IPs) have been increasingly appreciated as key signaling modulators. Fluctuations in their intracellular levels hugely impact the transfer of phosphates and the phosphorylation status of several target proteins. Pharmacological modulation of the proteins associated with PP-IP activities has proved to be beneficial in various pathological settings. IP7 has been extensively studied and found to play a key role in pathways associated with PP-IP activities. Three inositol hexakisphosphate kinase (IP6K) isoforms regulate IP7 synthesis in mammals. Genomic deletion or enzymic inhibition of IP6K1 has been shown to reduce cell invasiveness and migration capacity, protecting against chemical-induced carcinogenesis. IP6K1 could therefore be a useful target in anticancer treatment. Here, we summarize the current understanding that established IP6K1 and the other IP6K isoforms as possible targets for cancer therapy. However, it will be necessary to determine whether pharmacological inhibition of IP6K is safe enough to begin clinical study. The development of safe and selective inhibitors of IP6K isoforms is required to minimize undesirable effects.
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Affiliation(s)
- Mirko Minini
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy;
- Department of Surgery ‘P. Valdoni’, Sapienza University of Rome, 00161 Rome, Italy
- Systems Biology Group Lab, Sapienza University of Rome, 00185 Rome, Italy;
- Correspondence: (M.M.); (M.B.)
| | - Alice Senni
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy;
- Department of Surgery ‘P. Valdoni’, Sapienza University of Rome, 00161 Rome, Italy
| | - Vittorio Unfer
- Systems Biology Group Lab, Sapienza University of Rome, 00185 Rome, Italy;
| | - Mariano Bizzarri
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy;
- Systems Biology Group Lab, Sapienza University of Rome, 00185 Rome, Italy;
- Correspondence: (M.M.); (M.B.)
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6
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Bittner T, Wittwer C, Hauke S, Wohlwend D, Mundinger S, Dutta AK, Bezold D, Dürr T, Friedrich T, Schultz C, Jessen HJ. Photolysis of Caged Inositol Pyrophosphate InsP 8 Directly Modulates Intracellular Ca 2+ Oscillations and Controls C2AB Domain Localization. J Am Chem Soc 2020; 142:10606-10611. [PMID: 32459478 DOI: 10.1021/jacs.0c01697] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inositol pyrophosphates constitute a family of hyperphosphorylated signaling molecules involved in the regulation of glucose uptake and insulin sensitivity. While our understanding of the biological roles of inositol heptaphosphates (PP-InsP5) has greatly improved, the functions of the inositol octaphosphates ((PP)2-InsP4) have remained unclear. Here we present the synthesis of two enantiomeric cell-permeant and photocaged (PP)2-InsP4 derivatives and apply them to study the functions in living β-cells. Photorelease of the naturally occurring isomer 1,5-(PP)2-InsP4 led to an immediate and concentration-dependent reduction of intracellular calcium oscillations, while other caged inositol pyrophosphates (3,5-(PP)2-InsP4, 5-PP-InsP5, 1-PP-InsP5, 3-PP-InsP5) showed no immediate effect. Furthermore, uncaging of 1,5-(PP)2-InsP4 but not 3,5-(PP)2-InsP4 induced translocation of the C2AB domain of granuphilin from the plasma membrane to the cytosol. Granuphilin is involved in membrane docking of secretory vesicles. This suggests that 1,5-(PP)2-InsP4 impacts β-cell activity by regulating granule localization and/or priming and calcium signaling in concert.
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Affiliation(s)
- Tamara Bittner
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Christopher Wittwer
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Sebastian Hauke
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Daniel Wohlwend
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Stephan Mundinger
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Amit K Dutta
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Dominik Bezold
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Tobias Dürr
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Thorsten Friedrich
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany
| | - Carsten Schultz
- Cell Biology & Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University (OHSU), Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
| | - Henning J Jessen
- Department of Chemistry and Pharmacy, Albert-Ludwigs University Freiburg, Albertstrasse 21, 79104 Freiburg i.B., Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, 79104 Freiburg i.B., Germany.,Freiburg Research Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Albertstrasse 19, 79104 Freiburg i.B., Germany
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7
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Chakraborty A. The inositol pyrophosphate pathway in health and diseases. Biol Rev Camb Philos Soc 2018; 93:1203-1227. [PMID: 29282838 PMCID: PMC6383672 DOI: 10.1111/brv.12392] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 11/28/2017] [Accepted: 12/05/2017] [Indexed: 12/11/2022]
Abstract
Inositol pyrophosphates (IPPs) are present in organisms ranging from plants, slime moulds and fungi to mammals. Distinct classes of kinases generate different forms of energetic diphosphate-containing IPPs from inositol phosphates (IPs). Conversely, polyphosphate phosphohydrolase enzymes dephosphorylate IPPs to regenerate the respective IPs. IPPs and/or their metabolizing enzymes regulate various cell biological processes by modulating many proteins via diverse mechanisms. In the last decade, extensive research has been conducted in mammalian systems, particularly in knockout mouse models of relevant enzymes. Results obtained from these studies suggest impacts of the IPP pathway on organ development, especially of brain and testis. Conversely, deletion of specific enzymes in the pathway protects mice from various diseases such as diet-induced obesity (DIO), type-2 diabetes (T2D), fatty liver, bacterial infection, thromboembolism, cancer metastasis and aging. Furthermore, pharmacological inhibition of the same class of enzymes in mice validates the therapeutic importance of this pathway in cardio-metabolic diseases. This review critically analyses these findings and summarizes the significance of the IPP pathway in mammalian health and diseases. It also evaluates benefits and risks of targeting this pathway in disease therapies. Finally, future directions of mammalian IPP research are discussed.
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Affiliation(s)
- Anutosh Chakraborty
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, Saint Louis, MO 63104, U.S.A
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8
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Su Y, Yuan Y, Feng S, Ma S, Wang Y. High frequency stimulation induces sonic hedgehog release from hippocampal neurons. Sci Rep 2017; 7:43865. [PMID: 28262835 PMCID: PMC5338313 DOI: 10.1038/srep43865] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/01/2017] [Indexed: 12/27/2022] Open
Abstract
Sonic hedgehog (SHH) as a secreted protein is important for neuronal development in the central nervous system (CNS). However, the mechanism about SHH release remains largely unknown. Here, we showed that SHH was expressed mainly in the synaptic vesicles of hippocampus in both young postnatal and adult rats. High, but not low, frequency stimulation, induces SHH release from the neurons. Moreover, removal of extracellular Ca2+, application of tetrodotoxin (TTX), an inhibitor of voltage-dependent sodium channels, or downregulation of soluble n-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs) proteins, all blocked SHH release from the neurons in response to HFS. Our findings suggest a novel mechanism to control SHH release from the hippocampal neurons.
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Affiliation(s)
- Yujuan Su
- Laboratory of Neural Signal Transduction, Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yuan Yuan
- Laboratory of Neural Signal Transduction, Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Shengjie Feng
- Laboratory of Neural Signal Transduction, Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Shaorong Ma
- Laboratory of Neural Signal Transduction, Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yizheng Wang
- Laboratory of Neural Signal Transduction, Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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9
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Prokosch V, Chiwitt C, Rose K, Thanos S. Deciphering proteins and their functions in the regenerating retina. Expert Rev Proteomics 2014; 7:775-95. [DOI: 10.1586/epr.10.47] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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10
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Cyclic AMP promotes axon regeneration, lesion repair and neuronal survival in lampreys after spinal cord injury. Exp Neurol 2013; 250:31-42. [PMID: 24041988 DOI: 10.1016/j.expneurol.2013.09.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 01/10/2023]
Abstract
Axon regeneration after spinal cord injury in mammals is inadequate to restore function, illustrating the need to design better strategies for improving outcomes. Increasing the levels of the second messenger cyclic adenosine monophosphate (cAMP) after spinal cord injury enhances axon regeneration across a wide variety of species, making it an excellent candidate molecule that has therapeutic potential. However, several important aspects of the cellular and molecular mechanisms by which cAMP enhances axon regeneration are still unclear, such as how cAMP affects axon growth patterns, the molecular components within growing axon tips, the lesion scar, and neuronal survival. To address these points, we took advantage of the large, identified reticulospinal (RS) neurons in lamprey, a vertebrate that exhibits robust axon regeneration after a complete spinal cord transection. Application of a cAMP analog, db-cAMP, at the time of spinal cord transection increased the number of axons that regenerated across the lesion site. Db-cAMP also promoted axons to regenerate in straighter paths, prevented abnormal axonal growth patterns, increased the levels of synaptotagmin within axon tips, and increased the number of axotomized neurons that survived after spinal cord injury, thereby increasing the pool of neurons available for regeneration. There was also a transient increase in the number of microglia/macrophages and improved repair of the lesion site. Taken together, these data reveal several new features of the cellular and molecular mechanisms underlying cAMP-mediated enhancement of axon regeneration, further emphasizing the positive roles for this conserved pathway.
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11
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Kwon MJ, Nitsche BM, Arentshorst M, Jørgensen TR, Ram AFJ, Meyer V. The transcriptomic signature of RacA activation and inactivation provides new insights into the morphogenetic network of Aspergillus niger. PLoS One 2013; 8:e68946. [PMID: 23894378 PMCID: PMC3722221 DOI: 10.1371/journal.pone.0068946] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/04/2013] [Indexed: 12/23/2022] Open
Abstract
RacA is the main Rho GTPase in Aspergillus niger regulating polarity maintenance via controlling actin dynamics. Both deletion and dominant activation of RacA (Rac(G18V)) provoke an actin localization defect and thereby loss of polarized tip extension, resulting in frequent dichotomous branching in the ΔracA strain and an apolar growing phenotype for Rac(G18V). In the current study the transcriptomics and physiological consequences of these morphological changes were investigated and compared with the data of the morphogenetic network model for the dichotomous branching mutant ramosa-1. This integrated approach revealed that polar tip growth is most likely orchestrated by the concerted activities of phospholipid signaling, sphingolipid signaling, TORC2 signaling, calcium signaling and CWI signaling pathways. The transcriptomic signatures and the reconstructed network model for all three morphology mutants (ΔracA, Rac(G18V), ramosa-1) imply that these pathways become integrated to bring about different physiological adaptations including changes in sterol, zinc and amino acid metabolism and changes in ion transport and protein trafficking. Finally, the fate of exocytotic (SncA) and endocytotic (AbpA, SlaB) markers in the dichotomous branching mutant ΔracA was followed, demonstrating that hyperbranching does not per se result in increased protein secretion.
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Affiliation(s)
- Min Jin Kwon
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, Delft, The Netherlands
| | - Benjamin M. Nitsche
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
- Institute of Biotechnology, Department Applied and Molecular Microbiology, Berlin University of Technology, Berlin, Germany
| | - Mark Arentshorst
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, Delft, The Netherlands
| | - Thomas R. Jørgensen
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
| | - Arthur F. J. Ram
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, Delft, The Netherlands
- * E-mail: (AR); (VM)
| | - Vera Meyer
- Leiden University, Institute of Biology Leiden, Department Molecular Microbiology and Biotechnology, Leiden, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, Delft, The Netherlands
- Institute of Biotechnology, Department Applied and Molecular Microbiology, Berlin University of Technology, Berlin, Germany
- * E-mail: (AR); (VM)
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12
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Dong J, Wang Y, Wang Y, Wei W, Min H, Song B, Xi Q, Teng W, Chen J. Iodine deficiency increases apoptosis and decreases synaptotagmin-1 and PSD-95 in rat hippocampus. Nutr Neurosci 2013; 16:135-41. [DOI: 10.1179/1476830512y.0000000040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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13
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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14
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Tapocik JD, Luu TV, Mayo CL, Wang BD, Doyle E, Lee AD, Lee NH, Elmer GI. Neuroplasticity, axonal guidance and micro-RNA genes are associated with morphine self-administration behavior. Addict Biol 2013; 18:480-95. [PMID: 22804800 DOI: 10.1111/j.1369-1600.2012.00470.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuroadaptations in the ventral striatum (VS) and ventral midbrain (VMB) following chronic opioid administration are thought to contribute to the pathogenesis and persistence of opiate addiction. In order to identify candidate genes involved in these neuroadaptations, we utilized a behavior-genetics strategy designed to associate contingent intravenous drug self-administration with specific patterns of gene expression in inbred mice differentially predisposed to the rewarding effects of morphine. In a Yoked-control paradigm, C57BL/6J mice showed clear morphine-reinforced behavior, whereas DBA/2J mice did not. Moreover, the Yoked-control paradigm revealed the powerful consequences of self-administration versus passive administration at the level of gene expression. Morphine self-administration in the C57BL/6J mice uniquely up- or down-regulated 237 genes in the VS and 131 genes in the VMB. Interestingly, only a handful of the C57BL/6J self-administration genes (<3%) exhibited a similar expression pattern in the DBA/2J mice. Hence, specific sets of genes could be confidently assigned to regional effects of morphine in a contingent- and genotype-dependent manner. Bioinformatics analysis revealed that neuroplasticity, axonal guidance and micro-RNAs (miRNAs) were among the key themes associated with drug self-administration. Noteworthy were the primary miRNA genes H19 and micro-RNA containing gene (Mirg), processed, respectively, to mature miRNAs miR-675 and miR-154, because they are prime candidates to mediate network-like changes in responses to chronic drug administration. These miRNAs have postulated roles in dopaminergic neuron differentiation and mu-opioid receptor regulation. The strategic approach designed to focus on reinforcement-associated genes provides new insight into the role of neuroplasticity pathways and miRNAs in drug addiction.
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Affiliation(s)
| | - Truong V. Luu
- Department of Pharmacology and Physiology; The George Washington University Medical Center; Washington; DC; USA
| | - Cheryl L. Mayo
- Department of Psychiatry; Maryland Psychiatric Research Center; University of Maryland School of Medicine; Baltimore; MD; USA
| | - Bi-Dar Wang
- Department of Pharmacology and Physiology; The George Washington University Medical Center; Washington; DC; USA
| | - Erin Doyle
- Department of Pharmacology and Physiology; The George Washington University Medical Center; Washington; DC; USA
| | - Alec D. Lee
- Department of Pharmacology and Physiology; The George Washington University Medical Center; Washington; DC; USA
| | - Norman H. Lee
- Department of Pharmacology and Physiology; The George Washington University Medical Center; Washington; DC; USA
| | - Greg I. Elmer
- Department of Psychiatry; Maryland Psychiatric Research Center; University of Maryland School of Medicine; Baltimore; MD; USA
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15
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Yeo H, Kim HW, Mo J, Lee D, Han S, Hong S, Koh MJ, Sun W, Choi S, Rhyu IJ, Kim H, Lee HW. Developmental expression and subcellular distribution of synaptotagmin 11 in rat hippocampus. Neuroscience 2012; 225:35-43. [PMID: 22960622 DOI: 10.1016/j.neuroscience.2012.08.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 08/21/2012] [Accepted: 08/29/2012] [Indexed: 11/18/2022]
Abstract
Synaptotagmins are required for Ca(2+)-dependent membrane-trafficking in either neuronal synaptic vesicles or cellular membranes. Previous reports suggested that the synaptotagmin 11 (syt11) gene is involved in the development of schizophrenia based on the genomic analysis of patients. Parkin protein binds to the C2 domains of Syt11 which leads to the polyubiquitination of Syt11. However, where and how Syt11 performs its role in the brain is largely unknown. Here, we report that Syt11 is expressed mainly in the brain. In addition, exogenously expressed Syt11 in HEK293 cells can form higher molecular weight complex via its transmembrane domain. Also, Syt11 is targeted to both dendrite and axon compartments. Immunocytochemistry showed that Syt11 is juxtaposed to postsynaptic markers in both excitatory and inhibitory synapses. Both neuroligin 1 and 2, which are postsynaptic cell adhesion molecules and differentially induce excitatory and inhibitory presynapses, respectively, recruit Syt11 in neuron coculture. Immunogold electron microscopy analysis revealed that Syt11 exists mainly in presynaptic neurotransmitter vesicles and plasma membrane, and rarely in postsynaptic sites. These results suggest that Syt11 may contribute to the regulation of neurotransmitter release in the excitatory and inhibitory presynapses, and postsynapse-targeted membrane trafficking in dendrites.
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Affiliation(s)
- H Yeo
- Department of Anatomy and Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, 126-1, 5-Ka, Anam-Dong, Seongbuk-Gu, Seoul 136-705, Republic of Korea
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16
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Joung MJ, Mohan SK, Yu C. Molecular level interaction of inositol hexaphosphate with the C2B domain of human synaptotagmin I. Biochemistry 2012; 51:3675-83. [PMID: 22475172 DOI: 10.1021/bi300005w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Synaptotagmin I is a synaptic vesicle membrane protein that serves as a multifunctional regulator during the exocytosis of neurotransmitter release. It contains C2A and C2B domains. The binding of Ca(2+) to the C2A domain activates the exocytosis of secretory vesicles, while the binding of inositol polyphosphates (IP4-IP6) to the C2B domain inhibits this process. To understand the IP6-induced inhibition of exocytosis of secretory vesicles, we determined the three-dimensional structure of the C2B-IP6 complex by nuclear magnetic resonance (NMR). In this study, we have determined the binding constant by isothermal titration calorimetry. The circular dichroism measurements demonstrated that IP6 can stabilize the C2B molecule. We identified the binding site using (1)H-(15)N heteronuclear single-quantum coherence spectroscopy titration data and determined the structure of the C2B-IP6 complex using multidimensional NMR studies. This information will aid in the design of better pharmacological treatments for neurological disorders.
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Affiliation(s)
- Meng-Je Joung
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
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17
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Wang Y, Zhong J, Wei W, Gong J, Dong J, Yu F, Wang Y, Chen J. Developmental iodine deficiency and hypothyroidism impair neural development, upregulate caveolin-1, and downregulate synaptotagmin-1 in the rat cerebellum. Biol Trace Elem Res 2011; 144:1039-49. [PMID: 21611807 DOI: 10.1007/s12011-011-9089-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 05/16/2011] [Indexed: 01/30/2023]
Abstract
Adequate thyroid hormone is critical for cerebellar development. Developmental hypothyroidism induced by iodine deficiency during gestation and postnatal period results in permanent impairments of cerebellar development with an unclear mechanism. In the present study, we implicate cerebellar caveolin-1 and synaptotagmin-1, the two important molecules involved in neuronal development, in developmental iodine deficiency, and in developmental hypothyroidism. Two developmental rat models were created by administrating dam rats with either iodine-deficient diet or propylthiouracil (PTU, 5 or 15 ppm)-added drinking water from gestational day 6 till postnatal day (PN) 28. Nissl staining and the levels of caveolin-1 and synaptotagmin-1 in cerebella were assessed on PN28 and PN42. The results show that the numbers of Purkinje cells were reduced in the iodine-deficient and PTU-treated rats. The upregulation of caveolin-1 and the downregulation of synaptotagmin-1 were observed in both iodine-deficient and PTU-treated rats. These findings may implicate decreases in the number of Purkinje cells and the alterations in the levels of caveolin-1 and synaptotagmin-1 in the impairments of cerebellar development induced by developmental iodine deficiency and hypothyroidism.
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Affiliation(s)
- Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang, 110001, People's Republic of China
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18
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Kuo LT, Tsai SY, Groves MJ, An SF, Scaravilli F. Gene expression profile in rat dorsal root ganglion following sciatic nerve injury and systemic neurotrophin-3 administration. J Mol Neurosci 2011; 43:503-15. [PMID: 21061088 DOI: 10.1007/s12031-010-9473-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/28/2010] [Indexed: 12/14/2022]
Abstract
Following sciatic nerve transection in adult rats, a proportion of injured dorsal root ganglion (DRG) neurons die, through apoptosis, over the following 6 months. Previous studies showed that axotomy and neurotrophin-3 administration may have effects on expression of neurotrophins and their receptors in DRG. In the current study, the fourth and fifth lumbar DRGs of rats were examined 2 weeks after right sciatic nerve transection and ligation. The effects of axotomy and systemic NT-3 treatment on neuronal genes were investigated by microarray. The results demonstrated that bone morphogenetic protein (BMP) and Janus protein tyrosine kinase signaling pathways are induced in axotomized DRG, and PI-3 kinase and BMP pathways and genes controlling various cellular functions were induced after axotomy and NT-3 administration.
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Affiliation(s)
- Lu-Ting Kuo
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Yun-lin branch, No.579, Sec. 2, Yun-lin Rd., Dou-liou City, Yun-lin County, 640, Taiwan.
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19
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Stefaniuk M, Swiech L, Dzwonek J, Lukasiuk K. Expression of Ttyh1, a member of the Tweety family in neurons in vitro and in vivo and its potential role in brain pathology. J Neurochem 2010; 115:1183-94. [PMID: 20874767 DOI: 10.1111/j.1471-4159.2010.07023.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown that Ttyh1 mRNA is expressed in neurons and its expression is up-regulated in the brain during epileptogenesis and epilepsy. In this study, we aimed to elucidate the role of Ttyh1 in neurons. We found widespread expression of Ttyh1 protein in neurons in vivo and in vitro. Ttyh1 immunoreactivity in vitro was frequently found in invaginations of dendritic spines; however, Ttyh1, seldom co-localized with synaptic markers in vivo. Silencing Ttyh1 expression with siRNA in hippocampal cultures resulted in alterations of MAP2 distribution along neurites causing it to appear in the form of chains of beads. Over-expression of Ttyh1 caused intense neuritogenesis and the formation of numerous filopodia-like protrusions. Similar protrusions were also produced in SH-SY5Y neuroblastoma cells over-expressing Ttyh1. Using a biotin-streptavidin pull-down assay and mass spectrometry, we identified proteins that can form complexes with Ttyh1 in the brain. Ttyh1 binding proteins are often expressed in the endoplasmic reticulum or the Golgi apparatus or are localized at synapses. Finally, we found increased expression of Ttyh1 in the inner molecular layer of the dentate gyrus in an animal model of epilepsy. On the basis of our findings, we propose Ttyh1 involvement in brain pathology.
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Affiliation(s)
- Marzena Stefaniuk
- Laboratory of Epileptogenesis, The Nencki Institute of Experimental Biology, Warsaw, Poland
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20
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Pattaro C, De Grandi A, Vitart V, Hayward C, Franke A, Aulchenko YS, Johansson A, Wild SH, Melville SA, Isaacs A, Polasek O, Ellinghaus D, Kolcic I, Nöthlings U, Zgaga L, Zemunik T, Gnewuch C, Schreiber S, Campbell S, Hastie N, Boban M, Meitinger T, Oostra BA, Riegler P, Minelli C, Wright AF, Campbell H, van Duijn CM, Gyllensten U, Wilson JF, Krawczak M, Rudan I, Pramstaller PP. A meta-analysis of genome-wide data from five European isolates reveals an association of COL22A1, SYT1, and GABRR2 with serum creatinine level. BMC MEDICAL GENETICS 2010; 11:41. [PMID: 20222955 PMCID: PMC2848223 DOI: 10.1186/1471-2350-11-41] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 03/11/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Serum creatinine (S CR) is the most important biomarker for a quick and non-invasive assessment of kidney function in population-based surveys. A substantial proportion of the inter-individual variability in S CR level is explicable by genetic factors. METHODS We performed a meta-analysis of genome-wide association studies of S CR undertaken in five population isolates ('discovery cohorts'), all of which are part of the European Special Population Network (EUROSPAN) project. Genes showing the strongest evidence for an association with SCR (candidate loci) were replicated in two additional population-based samples ('replication cohorts'). RESULTS After the discovery meta-analysis, 29 loci were selected for replication. Association between SCR level and polymorphisms in the collagen type XXII alpha 1 (COL22A1) gene, on chromosome 8, and in the synaptotagmin-1 (SYT1) gene, on chromosome 12, were successfully replicated in the replication cohorts (p value = 1.0 x 10(-6) and 1.7 x 10(-4), respectively). Evidence of association was also found for polymorphisms in a locus including the gamma-aminobutyric acid receptor rho-2 (GABRR2) gene and the ubiquitin-conjugating enzyme E2-J1 (UBE2J1) gene (replication p value = 3.6 x 10(-3)). Previously reported findings, associating glomerular filtration rate with SNPs in the uromodulin (UMOD) gene and in the schroom family member 3 (SCHROOM3) gene were also replicated. CONCLUSIONS While confirming earlier results, our study provides new insights in the understanding of the genetic basis of serum creatinine regulatory processes. In particular, the association with the genes SYT1 and GABRR2 corroborate previous findings that highlighted a possible role of the neurotransmitters GABAA receptors in the regulation of the glomerular basement membrane and a possible interaction between GABAA receptors and synaptotagmin-I at the podocyte level.
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Affiliation(s)
- Cristian Pattaro
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy - Affiliated Institute of the University Lübeck, Lübeck, Germany
| | - Alessandro De Grandi
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy - Affiliated Institute of the University Lübeck, Lübeck, Germany
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Andre Franke
- Institute for Clinical Molecular Biology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Yurii S Aulchenko
- Genetic Epidemiology Unit, Departments of Epidemiology and Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Asa Johansson
- Department of Genetics and Pathology, Rudbeck laboratory, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Sarah H Wild
- Centre for Population Health Sciences, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, UK
| | - Scott A Melville
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy - Affiliated Institute of the University Lübeck, Lübeck, Germany
| | - Aaron Isaacs
- Genetic Epidemiology Unit, Departments of Epidemiology and Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Ozren Polasek
- Andrija Stampar School of Public Health, University of Zagreb Medical School, Rockefellerova 4, 10000 Zagreb, Croatia
- Gen-info Ltd, Ruzmarinka 17, 10000 Zagreb, Croatia
| | - David Ellinghaus
- Institute for Clinical Molecular Biology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Ivana Kolcic
- Andrija Stampar School of Public Health, University of Zagreb Medical School, Rockefellerova 4, 10000 Zagreb, Croatia
| | - Ute Nöthlings
- Popgen biobank, Christian-Albrechts-University Kiel, Kiel, Germany
- Institute for Experimental Medicine, Christian-Albrechts University Kiel, 24105 Kiel, Germany
| | - Lina Zgaga
- Andrija Stampar School of Public Health, University of Zagreb Medical School, Rockefellerova 4, 10000 Zagreb, Croatia
| | - Tatijana Zemunik
- Croatian Centre for Global Health, University of Split Medical School, Soltanska 2, 21000 Split, Croatia
| | - Carsten Gnewuch
- Institute for Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, D-93053 Regensburg, Germany
| | - Stefan Schreiber
- Institute for Clinical Molecular Biology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Susan Campbell
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Nick Hastie
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Mladen Boban
- Croatian Centre for Global Health, University of Split Medical School, Soltanska 2, 21000 Split, Croatia
| | - Thomas Meitinger
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr 1, D-85764 Neuherberg, Germany
| | - Ben A Oostra
- Genetic Epidemiology Unit, Departments of Epidemiology and Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Peter Riegler
- Hemodialysis Unit, Hospital of Merano, Merano, Italy
| | - Cosetta Minelli
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy - Affiliated Institute of the University Lübeck, Lübeck, Germany
| | - Alan F Wright
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK
| | - Harry Campbell
- Centre for Population Health Sciences, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, UK
| | - Cornelia M van Duijn
- Genetic Epidemiology Unit, Departments of Epidemiology and Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Ulf Gyllensten
- Department of Genetics and Pathology, Rudbeck laboratory, Uppsala University, SE-751 85, Uppsala, Sweden
| | - James F Wilson
- Centre for Population Health Sciences, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, UK
| | - Michael Krawczak
- Popgen biobank, Christian-Albrechts-University Kiel, Kiel, Germany
- Institute of Medical Informatics and Statistics, Christian-Albrechts-University, Kiel, Germany
| | - Igor Rudan
- Centre for Population Health Sciences, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, UK
- Gen-info Ltd, Ruzmarinka 17, 10000 Zagreb, Croatia
- Croatian Centre for Global Health, University of Split Medical School, Soltanska 2, 21000 Split, Croatia
| | - Peter P Pramstaller
- Institute of Genetic Medicine, European Academy Bozen/Bolzano (EURAC), Bolzano, Italy - Affiliated Institute of the University Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck, Lübeck, Germany
- Department of Neurology, Central Hospital, Bolzano, Italy
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Abstract
Synaptotagmins (Syts) are transmembrane proteins involved in the regulation of membrane trafficking. Here, we summarize literature data that provide growing evidence that several Syts are involved in the pathophysiological mechanisms of temporal lobe epilepsy and Parkinson's disease, as well as few reports related to brain ischemia and Alzheimer's disease (AD). We also report new data from our laboratories, showing changes of the expression of several Syts in Tg2576 mouse model of AD that may be related to neuroinflammation surrounding the beta-amyloid plaques. Furthermore, we demonstrate N-methyl-D-aspartate receptor-mediated upregulation of Syt 4 mRNA in a model of excitotoxic striatal lesion induced by unilateral striatal injection of quinolinic acid, associating the upregulation of Syt 4 with mechanisms of excitotoxicity. We propose that pharmacological manipulation of Syt expression in animal models of neurodegeneration should be further explored, as it may help to clarify the role of individual Syt isoforms in the regulation of membrane trafficking in neurodegeneration.
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Affiliation(s)
- Gordana Glavan
- Medical Faculty, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
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22
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Kami K, Rajesh S, Overduin M. Phospholipid-interacting proteins by solution-state NMR spectroscopy. Methods Mol Biol 2009; 462:291-306. [PMID: 19160678 DOI: 10.1007/978-1-60327-115-8_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Signaling lipids are found in specific subcellular membranes, where they recruit and regulate cytosolic proteins and contribute to bilayer structure and dynamics. These interactions are vital for signaling and membrane trafficking pathways and contribute to the organization, growth, and differentiation of the cell. However, the analysis of the physical and chemical mechanisms of membrane interaction and lipid recognition is technically challenging, motivating the development of new NMR methods to study lipid and bilayer binding by peripheral membrane proteins in solution. We describe methods that have been optimized for the FYVE and phox (PX) domains of the EEA1 and Vam7p proteins, respectively, both of which specifically recognize phosphatidylinositol 3-phosphate (PtdIns3P) within endocytic membranes. Solution-state NMR methods were used to characterize the phosphoinositide and membrane interaction sites and affinities and can be used to illustrate protein:micelle structures and phospholipid specificities. The methods are generally applicable and can be used to discover and characterize the phospholipid interactions of other membrane-interacting protein domains.
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Affiliation(s)
- Keiichiro Kami
- CR-UK Institute for Cancer Studies, School of Medicine, University of Birmingham, Birmingham, UK
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23
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Fuson KL, Ma L, Sutton RB, Oberhauser AF. The c2 domains of human synaptotagmin 1 have distinct mechanical properties. Biophys J 2009; 96:1083-90. [PMID: 19186144 PMCID: PMC2716670 DOI: 10.1016/j.bpj.2008.10.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022] Open
Abstract
Synaptotagmin 1 (Syt1) is the Ca(+2) receptor for fast, synchronous vesicle fusion in neurons. Because membrane fusion is an inherently mechanical, force-driven event, Syt1 must be able to adapt to the energetics of the fusion apparatus. Syt1 contains two C2 domains (C2A and C2B) that are homologous in sequence and three-dimensional in structure; yet, a number of observations have suggested that they have distinct biochemical and biological properties. In this study, we analyzed the mechanical stability of the C2A and C2B domains of human Syt1 using single-molecule atomic force microscopy. We found that stretching the C2AB domains of Syt1 resulted in two distinct unfolding force peaks. The larger force peak of approximately 100 pN was identified as C2B and the second peak of approximately 50 pN as C2A. Furthermore, a significant fraction of C2A domains unfolded through a low force intermediate that was not observed in C2B. We conclude that these domains have different mechanical properties. We hypothesize that a relatively small stretching force may be sufficient to deform the effector-binding regions of the C2A domain and modulate the affinity for soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptors (SNAREs), phospholipids, and Ca(+2).
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Affiliation(s)
- Kerry L. Fuson
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - Liang Ma
- Department of Neuroscience and Cell Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - R. Bryan Sutton
- Department of Neuroscience and Cell Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - Andres F. Oberhauser
- Department of Neuroscience and Cell Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
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24
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Kabayama H, Nakamura T, Takeuchi M, Iwasaki H, Taniguchi M, Tokushige N, Mikoshiba K. Ca2+ induces macropinocytosis via F-actin depolymerization during growth cone collapse. Mol Cell Neurosci 2008; 40:27-38. [PMID: 18848894 DOI: 10.1016/j.mcn.2008.08.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 08/26/2008] [Accepted: 08/27/2008] [Indexed: 02/02/2023] Open
Abstract
Growth cone collapse occurs in repulsive axon guidance and is accompanied by a reduction in the surface area of the plasma membrane of growth cones. However, the mechanism of this reduction is unclear. Here, we show that during growth cone collapse, caffeine-induced Ca(2+) release from ryanodine-sensitive Ca(2+) stores triggers the formation of large vacuoles in growth cones by macropinocytosis, a clathrin-independent endocytosis for the massive retrieval of the cellular plasma membrane, and subsequent retrograde membrane transport. We observed a significant correlation of the area of caffeine-induced macropinosomes with growth cone collapse. We also detected macropinocytosis induced by semaphorin 3A, a typical repulsive cue, and correlation between the area of semaphorin 3A-induced macropinocytic vacuoles and growth cone collapse. Moreover, jasplakinolide, an inhibitor of F-actin depolymerization, blocked caffeine-induced macropinocytosis. We propose that the coordinated regulation of actin cytoskeletal reorganization and macropinocytosis-mediated retrograde membrane trafficking may contribute to Ca(2+)-induced axon growth inhibition.
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Affiliation(s)
- Hiroyuki Kabayama
- Laboratory for Developmental Neurobiology, Brain Science Institute, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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25
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Xiao Z, Gong Y, Wang XF, Xiao F, Xi ZQ, Lu Y, Sun HB. Altered Expression of Synaptotagmin I In Temporal Lobe Tissue of Patients With Refractory Epilepsy. J Mol Neurosci 2008; 38:193-200. [DOI: 10.1007/s12031-008-9143-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Accepted: 08/05/2008] [Indexed: 10/21/2022]
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26
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Hernández-Deviez DJ, Howes MT, Laval SH, Bushby K, Hancock JF, Parton RG. Caveolin regulates endocytosis of the muscle repair protein, dysferlin. J Biol Chem 2007; 283:6476-88. [PMID: 18096699 DOI: 10.1074/jbc.m708776200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dysferlin and Caveolin-3 are plasma membrane proteins associated with muscular dystrophy. Patients with mutations in the CAV3 gene show dysferlin mislocalization in muscle cells. By utilizing caveolin-null cells, expression of caveolin mutants, and different mutants of dysferlin, we have dissected the site of action of caveolin with respect to dysferlin trafficking pathways. We now show that Caveolin-1 or -3 can facilitate exit of a dysferlin mutant that accumulates in the Golgi complex of Cav1(-/-) cells. In contrast, wild type dysferlin reaches the plasma membrane but is rapidly endocytosed in Cav1(-/-) cells. We demonstrate that the primary effect of caveolin is to cause surface retention of dysferlin. Caveolin-1 or Caveolin-3, but not specific caveolin mutants, inhibit endocytosis of dysferlin through a clathrin-independent pathway colocalizing with internalized glycosylphosphatidylinositol-anchored proteins. Our results provide new insights into the role of this endocytic pathway in surface remodeling of specific surface components. In addition, they highlight a novel mechanism of action of caveolins relevant to the pathogenic mechanisms underlying caveolin-associated disease.
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Affiliation(s)
- Delia J Hernández-Deviez
- Institute for Molecular Bioscience, Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4072, Australia
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27
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Abstract
Neuronal communication is tightly regulated in time and space. Following neuronal activation, an electrical signal triggers neurotransmitter (NT) release at the active zone. The process starts by the signal reaching the synapse followed by a fusion of the synaptic vesicle (SV) and diffusion of the released NT in the synaptic cleft. The NT then binds to the appropriate receptor and induces a membrane potential change at the target cell membrane. The entire process is controlled by a fairly small set of synaptic proteins, collectively called SYCONs. The biochemical features of SYCONs underlie the properties of NT release. SYCONs are characterized by their ability to detect and respond to changes in environmental signals. For example, consider synaptotagmin I (Syt1), a prototype of a protein family with over 20 gene and variants in mammals. Syt1 is a specific example of a multi-sensor device with a large repertoire of discrete states. Several of these states are stimulated by a local concentration of signaling molecules such as Ca2+. The ability of this protein to sense signaling molecules and to adopt multiple biochemical states is shared by other SYCONs such as the synapsins (Syns). Specific biochemical states of Syns determine the accessibility of SV for NT release. Each of these states is defined by a specific alternative spliced variant with a unique profile of phosphorylation modified sites. The plasticity of the synapse is a direct reflection of SYCON's multiple biochemical states. State transitions occurs in a wide range of time scales, and therefore these molecules need to cope with events that last milliseconds (i.e., exocytosis in fast responding synapses) and with events that can carry on for many minutes (i.e., organization of SV pools). We suggest that SYCONs are optimized throughout evolution as multi-sensor devices. A full repertoire of the switches leading to alternation of protein states and a detailed characterization of protein-protein network within the synapse is critical for the development of a dynamic model of synaptic transmission.
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Affiliation(s)
- Guy Brachya
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
| | - Chava Yanay
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
| | - Michal Linial
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
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28
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Urbach A, Bruehl C, Witte OW. Microarray‐based long‐term detection of genes differentially expressed after cortical spreading depression. Eur J Neurosci 2006; 24:841-56. [PMID: 16930413 DOI: 10.1111/j.1460-9568.2006.04862.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spreading depression (SD) is a slowly propagating wave of neuronal depolarization altering ion homeostasis, blood flow and energy metabolism without causing irreversible damage of the tissue. As SD has been implicated in several neurological diseases including migraine and stroke, understanding these disorders requires systematic knowledge of the processes modified by SD. Thus, we induced repetitive SD in the rat cerebral cortex by topical application of 3 m KCl for approximately 2 h and evaluated the kinetics of SD-induced changes in cortical gene expression for up to 30 days using Affymetrix RAE230A arrays. The temporal profile showed a rapid expression of immediate early genes, genes associated with inflammation, metabolism, stress and DNA repair, ion transport, and genes that play a role in growth/differentiation. Stress-response genes could still be detected after 24 h. At this time, induced genes were mainly related to the cell membrane and adhesion, or to the cytoskeleton. A subset of genes was still affected even 30 days after SD. Real-time polymerase chain reactions and immunohistochemistry confirmed the microarray results for several of the transcripts. Our findings demonstrate a temporal pattern of gene expression which might promote tissue remodeling and cortical plasticity, and might probably account for the mediation of neuronal tolerance towards subsequent ischemia.
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Affiliation(s)
- Anja Urbach
- Department of Neurology, Friedrich-Schiller-University, Erlanger Allee 101, 07747 Jena, Germany.
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29
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Bolsover SR. Calcium signalling in growth cone migration. Cell Calcium 2005; 37:395-402. [PMID: 15820386 DOI: 10.1016/j.ceca.2005.01.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2004] [Accepted: 01/06/2005] [Indexed: 11/23/2022]
Abstract
Growth cones, the motile structures at the tips of advancing axons and dendrites, respond to a wide range of cues by either turning towards or away from the cue. Cytosolic calcium signals appear to mediate a large fraction of both types of response. Calcium signals can be generated by influx through plasma membrane channels or by release from intracellular stores. While neurotransmitters can elicit calcium influx through ionotropic receptors, other chemical cues open plasma membrane voltage gated calcium channels by a mechanism other than a change of membrane voltage. In general attractive cues generate spatially and temporally restricted calcium increases that are difficult to detect using conventional indicators. One target for these calcium signals is calmodulin dependent protein kinase II. Repulsive cues generate spatially and temporally more diffuse calcium increases that can be more readily detected using fluorescent indicators. One target for these is the phosphatase calcineurin, which may act by dephosphorylating GAP43 and allowing the latter to cap actin filaments.
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Affiliation(s)
- Stephen R Bolsover
- Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK.
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30
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Li RF, Zhang F, Lu YJ, Sui SF. Specific interaction between Smad1 and CHIP: a surface plasmon resonance study. Colloids Surf B Biointerfaces 2005; 40:133-6. [PMID: 15708501 DOI: 10.1016/j.colsurfb.2004.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The TGF-beta superfamily signaling pathway regulates many important biological processes, including cell growth, differentiation and embryonic pattern formation. Smad1, a member of this signaling pathway that functions downstream of serine/threonine kinase receptors, has ability to interact with carboxyl terminus of Hsc70-interacting protein (CHIP), which is an E3 ubiquitin ligase in other cases. It has been reported that Smurf1, a member of the Hect family E3 ubiquitin ligases, can target Smad1 to 26S proteasome for degradation. In this paper, we studied the interaction of Smad1 and CHIP by combination of surface plasmon resonance and supported monolayer approach. The specific binding of Smad1 to CHIP indicates that the degradation of Smad1 may also be mediated by CHIP, and CHIP may play an essential role in the TGF-beta signaling pathway.
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Affiliation(s)
- Ren-Feng Li
- Department of Biological Sciences and Biotechnology, State-Key Laboratory of Biomembrane, Tsinghua University, Beijing 100084, PR China
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31
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Abstract
Membrane vesicle cycling is orchestrated through the combined actions of proteins and lipids. At neuronal synapses, this orchestration must meet the stringent demands of speed, fidelity and sustainability of the synaptic vesicle cycle that mediates neurotransmission. Historically, the lion's share of the attention has been focused on the proteins that are involved in this cycle; but, in recent years, it has become clear that the previously unheralded plasma membrane and vesicle lipids are also key regulators of this cycle. This article reviews recent insights into the roles of lipid-modifying enzymes and lipids in the acute modulation of neurotransmission.
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Affiliation(s)
- Jeffrey Rohrbough
- Department of Biological Sciences, Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235-1634, USA
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32
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Abstract
Muscular dystrophy covers a group of genetically determined disorders that cause progressive weakness and wasting of the skeletal muscles. Dysferlin was identified as a gene mutated in limb-girdle muscular dystrophy (type 2B) and Miyoshi myopathy. The discovery of dysferlin revealed a new family of proteins, known as the ferlin family, which includes four different genes. Recent work suggests the function of dysferlin in membrane repair and demonstrates that defective membrane repair is a novel mechanism of muscle degeneration. These findings reveal the importance of a basic cellular function in skeletal muscle and a new class of muscular dystrophy where the defect lies in the maintenance, not the structure, of the plasma membrane. Here, we discuss the current knowledge of dysferlin function in the repair of the plasma membrane of the skeletal muscle cells.
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Affiliation(s)
- Dimple Bansal
- Howard Hughes Medical Institute, Department of Physiology and Biophysics and Department of Neurology, University of Iowa, Roy J. & Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
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33
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Cisternas FA, Vincent JB, Scherer SW, Ray PN. Cloning and characterization of human CADPS and CADPS2, new members of the Ca2+-dependent activator for secretion protein family. Genomics 2003; 81:279-91. [PMID: 12659812 DOI: 10.1016/s0888-7543(02)00040-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The recent identification of some of the components involved in regulated and constitutive exocytotic pathways has yielded important insights into the mechanisms of membrane trafficking and vesicle secretion. To understand precisely the molecular events taking place during vesicle exocytosis, we must identify all of the proteins implicated in these pathways. In this paper we describe the full-length cloning and characterization of human CADPS and CADPS2, two new homologs of the mouse Cadps protein involved in large dense-core vesicle (LDCV)-regulated exocytosis. We show that these two genes have disparate RNA expression patterns, with CADPS restricted to neural and endocrine tissues and CADPS2 expressed ubiquitously. We also identify a C2 domain, a known protein motif involved in calcium and phospholipid interactions, in both CADPS and CADPS2. We propose that CADPS functions as a calcium sensor in regulated exocytosis, whereas CADPS2 acts as a calcium sensor in constitutive vesicle trafficking and secretion. CADPS and CADPS2 were determined to span 475 kb and 561 kb on human chromosomes 3p21.1 and 7q31.3, respectively. The q31-q34 of human chromosome 7 has recently been identified to contain a putative susceptibility locus for autism (AUTS1). The function, expression profile, and location of CADPS2 make it a candidate gene for autism, and thus we conducted mutation screening for all 28 exons in 90 unrelated autistic individuals. We identified several nucleotide substitutions, including only one that would affect the amino acid sequence. No disease-specific variants were identified.
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Affiliation(s)
- Felipe A Cisternas
- Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada
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Kobayashi S, Ohno K, Iwakuma M, Kaneda Y, Saji M. Synaptotagmin I hypothalamic knockdown prevents amygdaloid seizure-induced damage of hippocampal neurons but not of entorhinal neurons. Neurosci Res 2002; 44:455-65. [PMID: 12445633 DOI: 10.1016/s0168-0102(02)00172-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously demonstrated that an acute pharmacological interruption of the afferent inputs from the hypothalamus to the hippocampus resulted in the blockade of the genesis and spread of intra-amygdala kainate-induced seizure activity in the hippocampus. This finding suggests that a sustained interruption of the hypothalamic stimulative influences may completely prevent amygdaloid seizure-induced hippocampal neuron damage. To test this assumption, we delivered antisense oligodeoxynucleotides (ODNs) against synaptotagmin I, a regulatory protein of the transmitter release machinery, into the hypothalamus by using a Hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer technique. Four days prior to the induction of status epilepticus by intra-amygdala injection of kainate, the synaptotagmin I antisense was injected into the supramammillary nucleus (SuM) of the hypothalamus to chronically suppress the stimulative influences to the hippocampus via the reduction of transmitter release. The synaptotagmin I hypothalamic knockdown resulted in the almost complete prevention of seizure-induced damage of hippocampal neurons but not of entorhinal neurons following the kainate-induced amygdaloid seizures. This result suggests that the hypothalamic stimulative influences to the hippocampus have a major contribution to the amygdaloid seizure-induced hippocampal sclerosis, probably via disinhibition mechanism.
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Affiliation(s)
- Shizuka Kobayashi
- Department of Physiology, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 228-8555, Japan.
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35
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Lu YJ, He Y, Sui SF. Inositol hexakisphosphate (InsP6) can weaken the Ca(2+)-dependent membrane binding of C2AB domain of synaptotagmin I. FEBS Lett 2002; 527:22-6. [PMID: 12220627 DOI: 10.1016/s0014-5793(02)03156-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The synaptic vesicle protein synaptotagmin I has been proposed to serve as a Ca(2+) sensor for rapid exocytosis. In the present work, two fragments of the large cytoplasmic domain of synaptotagmin I, C2A and C2AB, were compared by combining surface plasmon resonance with circular dichroism and fluorescence techniques. C2AB and C2A had almost identical membrane binding constants, indicating that C2A is the predominate domain to bind to negatively charged phospholipids. After reacting with inositol hexakisphosphate (InsP6) a conformational change of C2AB was detected in the presence of liposome. The InsP6 binding notably weakened the Ca(2+)-dependent C2AB-membrane interaction, which suggests that InsP6 may act as a modulator of neurotransmitter release by altering the state of synaptotagmin-phospholipid interaction.
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Affiliation(s)
- Ying-Jie Lu
- Department of Biological Sciences and Biotechnology, State Key Laboratory of Biomembrane, Tsinghua University, 100084, Beijing, PR China
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36
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Chuhma N, Ohmori H. Role of Ca(2+) in the synchronization of transmitter release at calyceal synapses in the auditory system of rat. J Neurophysiol 2002; 87:222-8. [PMID: 11784744 DOI: 10.1152/jn.00235.2001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The synchronization of transmitter release in the synapse of the medial nucleus of the trapezoid body (MNTB) is achieved during early postnatal development as a consequence of elimination of delayed asynchronous releases and appears to reflect changes in the dynamics of Ca(2+) entry and clearance. To examine the role of Ca(2+) in regulating synchronization of transmitter release in the mature synapse (after postnatal day 9, P9), we perturbed Ca(2+) dynamics systematically. Replacement of external Ca(2+) (2 mM) with Sr(2+) induced delayed asynchronous release following the major EPSC. We tried to reproduce asynchronous releases without using Sr(2+) and instead by manipulating the time course and the size of Ca(2+) transient in the presynaptic terminal, under the assumption that replacement of external Na(+) with Li(+) or application of eosin-Y would prolong the lifetime of Ca(2+) transient by reducing the rate of Ca(2+) extrusion from the terminal. With application of Li(+), Ca(2+) transient in the terminal was prolonged, the EPSC decay time course was prolonged, and the EPSC amplitude increased. However, these EPSCs were not followed by delayed asynchronous release. When Ca(2+) influx was reduced, either by partial Ca(2+) channel blockade with a low concentration of Cd(2+) or omega-agatoxin IVA, a marked asynchronous release resulted. This was further enhanced by the combined application of Li(+) or eosin-Y. These results suggest that cooperative increases of both Ca(2+) influx and Ca(2+) clearance capacities leading to a sharper Ca(2+) spike in the presynaptic terminal underlie synchronized transmitter release in the presynaptic terminal of the MNTB.
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Affiliation(s)
- Nao Chuhma
- Department of Physiology, Faculty of Medicine, Kyoto University, Kyoto 606-8501, Japan
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37
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Wenk MR, Pellegrini L, Klenchin VA, Di Paolo G, Chang S, Daniell L, Arioka M, Martin TF, De Camilli P. PIP kinase Igamma is the major PI(4,5)P(2) synthesizing enzyme at the synapse. Neuron 2001; 32:79-88. [PMID: 11604140 DOI: 10.1016/s0896-6273(01)00456-1] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Disruption of the presynaptically enriched polyphosphoinositide phosphatase synaptojanin 1 leads to an increase of clathrin-coated intermediates and of polymerized actin at endocytic zones of nerve terminals. These changes correlate with elevated levels of PI(4,5)P(2) in neurons. We report that phosphatidylinositol phosphate kinase type Igamma (PIPKIgamma), a major brain PI(4)P 5-kinase, is concentrated at synapses. Synaptojanin 1 and PIPKIgamma antagonize each other in the recruitment of clathrin coats to lipid membranes. Like synaptojanin 1 and other proteins involved in endocytosis, PIPKIgamma undergoes stimulation-dependent dephosphorylation. These results implicate PIPKIgamma in the synthesis of a PI(4,5)P(2) pool that acts as a positive regulator of clathrin coat recruitment and actin function at the synapse.
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Affiliation(s)
- M R Wenk
- Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA
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38
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Kishimoto T, Liu TT, Ninomiya Y, Takagi H, Yoshioka T, Ellis-Davies GC, Miyashita Y, Kasai H. Ion selectivities of the Ca(2+) sensors for exocytosis in rat phaeochromocytoma cells. J Physiol 2001; 533:627-37. [PMID: 11410622 PMCID: PMC2278662 DOI: 10.1111/j.1469-7793.2001.t01-1-00627.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. The ion selectivities of the Ca(2+) sensors for the two components of exocytosis in rat phaeochromocytoma (PC12) cells were examined by measurement of membrane capacitance and amperometry. The cytosolic concentrations of metal ions were increased by photolysis of caged-Ca(2+) compounds and measured with low-affinity indicators benzothiazole coumarin (BTC) or 5-nitrobenzothiazole coumarin (BTC-5N). 2. The Ca(2+)-induced increases in membrane capacitance comprised two phases with time constants of 30--100 ms and 5 s. Amperometric events reflecting the exocytosis of large dense-core vesicles occurred selectively in the slow phase, even with increases in the cytosolic Ca(2+) concentration of > 0.1 mM. 3. The slow component of exocytosis was activated by all metal ions investigated, including Cd(2+) (median effective concentration, 18 pM), Mn(2+) (500 nM), Co(2+) (900 nM), Ca(2+) (8 microM), Sr(2+) (180 microM), Ba(2+) (280 microM) and Mg(2+) (> 5 mM). In contrast, the fast component of exocytosis was activated by Cd(2+) (26 pM), Mn(2+) (620 nM), Ca(2+) (24 microM) and Sr(2+) (320 microM), but was only slightly increased by Ba(2+) (> 2 mM) and Co(2+) and not at all by Mg(2+). 4. The fast component, but not the slow component, was competitively blocked by Na(+) (median effective concentration, 44 mM) but not by Li(+), K(+) or Cs(+). Thus, the Ca(2+) sensor for the fast component of exocytosis is more selective than is that for the slow component; moreover, this selectivity appears to be based on ionic radius, with cations with radii of 0.84 to 1.13 A (1 A = 0.1 nm) being effective. 5. These data support a role for synaptotagmin--phospholipid as the Ca(2+) sensor for the exocytosis of large dense-core vesicles and they suggest that an additional Ca(2+)-sensing mechanism operates in the synchronous exocytosis of synaptic-like vesicles.
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Affiliation(s)
- T Kishimoto
- Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan.
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39
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Abstract
Recent work has established that different geometric arrangements of calcium channels are found at different presynaptic terminals, leading to a wide spectrum of calcium signals for triggering neurotransmitter release. These calcium signals are apparently transduced by synaptotagmins - calcium-binding proteins found in synaptic vesicles. New biochemical results indicate that all synaptotagmins undergo calcium-dependent interactions with membrane lipids and a number of other presynaptic proteins, but which of these interactions is responsible for calcium-triggered transmitter release remains unclear.
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Affiliation(s)
- G J Augustine
- Department of Neurobiology, Box 3209, Duke University Medical Center, Durham, NC 27710, USA.
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40
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Mehrotra B, Myszka DG, Prestwich GD. Binding kinetics and ligand specificity for the interactions of the C2B domain of synaptogmin II with inositol polyphosphates and phosphoinositides. Biochemistry 2000; 39:9679-86. [PMID: 10933784 DOI: 10.1021/bi000487o] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synaptotagmin II (Syt II) is a key protein in the calcium-dependent exocytosis of synaptic vesicles. It contains two domains homologous to the C2 regulatory region of protein kinase C. The C2A domain acts as a calcium sensor, while the C2B domain has high affinity for inositol polyphosphates (InsP(n)()s) and phosphoinositide polyphosphates (PtdInsP(n)()s). We describe the use of a surface plasmon resonance biosensor in determining the binding kinetics of the C2B domain with InsP(n)() and PtdInsP(n) ligands. Biosensor surfaces were prepared with covalently attached Ins(1,4,5)P(3), Ins(1,3,4,5)P(4), and InsP(6) ligands. The interactions of bacterially expressed His(6)-tagged C2B and (C2A+C2B) domains of Syt II were examined in the presence and absence of competing InsP(n)s and PtdInsP(n)s. Both His(6)-C2B and His(6)-(C2A+C2B) exhibited the highest affinity for the Ins(1,3,4,5)P(4)-modified surface with a K(D) value of 6 nM. The His(6)-(C2A+C2B) had a 10-fold lower association rate constant for the InsP(6)-linked surface (k(a) = 4.6 x 10(3) M(-1) s(-1)) than for the Ins(1,3,4,5)P(4)-modified surface (k(a) = 6.8 x 10(4) M(-1) s(-1)). Two water-soluble phosphoinositides, dioctanoyl-PtdIns(3,4,5)P(3) and dioctanoyl-PtdIns(4,5)P(2), were superior to the soluble InsP(n)s in displacing binding to the Ins(1,3,4,5)P(4)-modified surface. The binding of His(6)-C2B and His(6)-(C2A+C2B) to InsP(n) surfaces did not show significant calcium dependence. These data support a model in which the binding of the C2B domain of Syt II to PtdInsP(n)s is important for the docking and/or fusion of the secretory vesicles to the synaptic plasma membrane.
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Affiliation(s)
- B Mehrotra
- Department of Medicinal Chemistry, The University of Utah, 30 South 2000 East, Room 201, Salt Lake City, Utah 84112-5820, USA
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41
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Zheng L, Krishnamoorthi R, Zolkiewski M, Wang X. Distinct Ca2+ binding properties of novel C2 domains of plant phospholipase dalpha and beta. J Biol Chem 2000; 275:19700-6. [PMID: 10777500 DOI: 10.1074/jbc.m001945200] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Of the isoforms of plant phospholipase D (PLD) that have been cloned and characterized, PLDalpha requires millimolar levels of Ca(2+) for optimal activity, whereas PLDbeta is most active at micromolar concentrations of Ca(2+). Multiple amino acid sequence alignments suggest that PLDalpha and PLDbeta both contain a Ca(2+)-dependent phospholipid-binding C2 domain near their N termini. In the present study, we expressed and characterized the putative C2 domains of PLDalpha and PLDbeta, designated PLDalpha C2 and PLDbeta C2, by CD spectroscopy, isothermal titration calorimetry, and phospholipid binding assay. Both PLD C2 domains displayed CD spectra consistent with anticipated major beta-sheet structures but underwent spectral changes upon binding Ca(2+); the magnitude was larger for PLDbeta C2. These conformational changes, not shown by any of the previously characterized C2 domains of animal origin, occurred at micromolar Ca(2+) concentrations for PLDbeta C2 but at millimolar levels of the cation for PLDalpha C2. PLDbeta C2 exhibited three Ca(2+)-binding sites: one with a dissociation constant (K(d)) of 0.8 microm and the other two with a K(d) of 24 micrometer. In contrast, isothermal titration calorimetry data of PLDalpha C2 were consistent with 1-3 low affinity Ca(2+)-binding sites with K(d) in the range of 590-470 micrometer. The thermodynamics of Ca(2+) binding markedly differed for the two C2 domains. Likewise, PLDbeta C2 bound phosphatidylcholine (PC), the substrate of PLD, in the presence of submillimolar Ca(2+) concentrations, whereas PLDalpha C2 did so only in the presence of millimolar levels of the metal ion. Both C2 domains bound phosphatidylinoistol 4,5-bisphosphate, a regulator of PC hydrolysis by PLD. However, added Ca(2+) displaced the bound phosphatidylinoistol 4,5-bisphosphate. Ca(2+) and PC binding properties of PLDalpha C2 and PLDbeta C2 follow a trend similar to the Ca(2+) requirements of the whole enzymes, PLDalpha and PLDbeta, for PC hydrolysis. Taken together, the results suggest that the C2 domains of PLDalpha and PLDbeta have novel structural features and serve as handles by which Ca(2+) differentially regulates the activities of the isoforms.
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Affiliation(s)
- L Zheng
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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42
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Lee C, Kim SR, Chung JK, Frohman MA, Kilimann MW, Rhee SG. Inhibition of phospholipase D by amphiphysins. J Biol Chem 2000; 275:18751-8. [PMID: 10764771 DOI: 10.1074/jbc.m001695200] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two distinct proteins inhibiting phospholipase D (PLD) activity in rat brain cytosol were previously purified and identified as synaptojanin and AP180, which are specific to nerve terminals and associate with the clathrin coat. Two additional PLD-inhibitory proteins have now been purified and identified as the amphiphysins I and II, which forms a heterodimer that also associates with the clathrin coat. Bacterially expressed recombinant amphiphysins inhibited both PLD1 and PLD2 isozymes in vitro with a potency similar to that of brain amphiphysin (median inhibitory concentration of approximately 15 nm). Expressions of either amphiphysin in COS-7 cells reduced activity of endogenous PLD as well as exogenously expressed PLD1 and PLD2. Coprecipitation experiments suggested that the inhibitory effect of amphiphysins results from their direct interaction with PLDs. The NH(2) terminus of amphiphysin I was critical for both inhibition of and binding to PLD. Phosphatidic acid formed by signal-induced PLD is thought to be required for the assembly of clathrin-coated vesicles during endocytosis. Thus, the inhibition of PLD by amphiphysins, synaptojanin, and AP180 might play an important role in synaptic vesicle trafficking.
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Affiliation(s)
- C Lee
- Laboratory of Cell Signaling, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-0320, USA
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43
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Abstract
We present a summary of the structures of 13 proteins involved in the docking and fusion of intracellular transport vesicles to their target membranes.
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Affiliation(s)
- J A Ybe
- G.W. Hooper Foundation, Box 0552, Department of Microbiology and Immunology, Department of Biopharmaceutical Sciences, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA
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Abstract
The past 20 years have witnessed tremendous progress in our understanding of the molecular machinery that controls protein and membrane transport between organelles (Scheckman R, Orci L. Coat proteins and vesicle budding. Science 1996;271: 1526-1533 and Rothman JE. Mechanisms of intracellular protein transport. Nature 1994;372: 55-63.) The research efforts responsible for these impressive advances have largely focused on the identification and characterization of protein factors that participate in membrane trafficking events. The role of membranes and their lipid constituents has received considerably less attention. Indeed, until rather recently, popular models for mechanisms of membrane trafficking had relegated membrane lipids to the status of a passive platform, subject to deformation by the action of coat proteins whose polymerization and depolymerization govern vesicle budding and fusion reactions. The 1990s, and particularly its last half, has brought fundamental reappraisals of the interface of lipids and lipid metabolism in regulating intracellular membrane trafficking events. Some of the emerging themes are reviewed here.
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Affiliation(s)
- R P Huijbregts
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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Cremona O, Di Paolo G, Wenk MR, Lüthi A, Kim WT, Takei K, Daniell L, Nemoto Y, Shears SB, Flavell RA, McCormick DA, De Camilli P. Essential role of phosphoinositide metabolism in synaptic vesicle recycling. Cell 1999; 99:179-88. [PMID: 10535736 DOI: 10.1016/s0092-8674(00)81649-9] [Citation(s) in RCA: 674] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Growing evidence suggests that phosphoinositides play an important role in membrane traffic. A polyphosphoinositide phosphatase, synaptojanin 1, was identified as a major presynaptic protein associated with endocytic coated intermediates. We report here that synaptojanin 1-deficient mice exhibit neurological defects and die shortly after birth. In neurons of mutant animals, PI(4,5)P2 levels are increased, and clathrin-coated vesicles accumulate in the cytomatrix-rich area that surrounds the synaptic vesicle cluster in nerve endings. In cell-free assays, reduced phosphoinositide phosphatase activity correlated with increased association of clathrin coats with liposomes. Intracellular recording in hippocampal slices revealed enhanced synaptic depression during prolonged high-frequency stimulation followed by delayed recovery. These results provide genetic evidence for a crucial role of phosphoinositide metabolism in synaptic vesicle recycling.
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Affiliation(s)
- O Cremona
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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