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Khurana H, Baratam K, Bhattacharyya S, Srivastava A, Pucadyil TJ. Mechanistic analysis of a novel membrane-interacting variable loop in the pleckstrin-homology domain critical for dynamin function. Proc Natl Acad Sci U S A 2023; 120:e2215250120. [PMID: 36888655 PMCID: PMC10089193 DOI: 10.1073/pnas.2215250120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/08/2023] [Indexed: 03/09/2023] Open
Abstract
Classical dynamins are best understood for their ability to generate vesicles by membrane fission. During clathrin-mediated endocytosis (CME), dynamin is recruited to the membrane through multivalent protein and lipid interactions between its proline-rich domain (PRD) with SRC Homology 3 (SH3) domains in endocytic proteins and its pleckstrin-homology domain (PHD) with membrane lipids. Variable loops (VL) in the PHD bind lipids and partially insert into the membrane thereby anchoring the PHD to the membrane. Recent molecular dynamics (MD) simulations reveal a novel VL4 that interacts with the membrane. Importantly, a missense mutation that reduces VL4 hydrophobicity is linked to an autosomal dominant form of Charcot-Marie-Tooth (CMT) neuropathy. We analyzed the orientation and function of the VL4 to mechanistically link data from simulations with the CMT neuropathy. Structural modeling of PHDs in the cryo-electron microscopy (cryo-EM) cryoEM map of the membrane-bound dynamin polymer confirms VL4 as a membrane-interacting loop. In assays that rely solely on lipid-based membrane recruitment, VL4 mutants with reduced hydrophobicity showed an acute membrane curvature-dependent binding and a catalytic defect in fission. Remarkably, in assays that mimic a physiological multivalent lipid- and protein-based recruitment, VL4 mutants were completely defective in fission across a range of membrane curvatures. Importantly, expression of these mutants in cells inhibited CME, consistent with the autosomal dominant phenotype associated with the CMT neuropathy. Together, our results emphasize the significance of finely tuned lipid and protein interactions for efficient dynamin function.
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Affiliation(s)
- Himani Khurana
- Indian Institute of Science Education and Research, Pune411008, India
| | | | | | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru560012, India
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Imoto Y, Raychaudhuri S, Ma Y, Fenske P, Sandoval E, Itoh K, Blumrich EM, Matsubayashi HT, Mamer L, Zarebidaki F, Söhl-Kielczynski B, Trimbuch T, Nayak S, Iwasa JH, Liu J, Wu B, Ha T, Inoue T, Jorgensen EM, Cousin MA, Rosenmund C, Watanabe S. Dynamin is primed at endocytic sites for ultrafast endocytosis. Neuron 2022; 110:2815-2835.e13. [PMID: 35809574 PMCID: PMC9464723 DOI: 10.1016/j.neuron.2022.06.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 03/24/2022] [Accepted: 06/09/2022] [Indexed: 02/06/2023]
Abstract
Dynamin mediates fission of vesicles from the plasma membrane during endocytosis. Typically, dynamin is recruited from the cytosol to endocytic sites, requiring seconds to tens of seconds. However, ultrafast endocytosis in neurons internalizes vesicles as quickly as 50 ms during synaptic vesicle recycling. Here, we demonstrate that Dynamin 1 is pre-recruited to endocytic sites for ultrafast endocytosis. Specifically, Dynamin 1xA, a splice variant of Dynamin 1, interacts with Syndapin 1 to form molecular condensates on the plasma membrane. Single-particle tracking of Dynamin 1xA molecules confirms the liquid-like property of condensates in vivo. When Dynamin 1xA is mutated to disrupt its interaction with Syndapin 1, the condensates do not form, and consequently, ultrafast endocytosis slows down by 100-fold. Mechanistically, Syndapin 1 acts as an adaptor by binding the plasma membrane and stores Dynamin 1xA at endocytic sites. This cache bypasses the recruitment step and accelerates endocytosis at synapses.
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Affiliation(s)
- Yuuta Imoto
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Sumana Raychaudhuri
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ye Ma
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Pascal Fenske
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Eduardo Sandoval
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kie Itoh
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Eva-Maria Blumrich
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK; The Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK; Simons Initiatives for the Developing Brain, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK
| | - Hideaki T Matsubayashi
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Lauren Mamer
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Fereshteh Zarebidaki
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Thorsten Trimbuch
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Shraddha Nayak
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Janet H Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Jian Liu
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK
| | - Bin Wu
- The Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Baltimore, MD 21205, USA
| | - Takanari Inoue
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Erik M Jorgensen
- HHMI, Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK; The Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK; Simons Initiatives for the Developing Brain, University of Edinburgh, Edinburgh, Scotland EH8 9XD, UK
| | - Christian Rosenmund
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA.
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3
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Shi B, Jin YH, Wu LG. Dynamin 1 controls vesicle size and endocytosis at hippocampal synapses. Cell Calcium 2022; 103:102564. [PMID: 35220002 PMCID: PMC9009158 DOI: 10.1016/j.ceca.2022.102564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/27/2022] [Accepted: 02/15/2022] [Indexed: 11/16/2022]
Abstract
Following calcium-triggered vesicle exocytosis, endocytosis regenerates vesicles to maintain exocytosis and thus synaptic transmission, which underlies neuronal circuit activities. Although most molecules involved in endocytosis have been identified, it remains rather poorly understood how endocytic machinery regulates vesicle size. Vesicle size, together with the transmitter concentration inside the vesicle, determines the amount of transmitter the vesicle can release, the quantal size, that may control the strength of synaptic transmission. Here, we report that, surprisingly, knockout of the GTPase dynamin 1, the most abundant brain dynamin isoform known to catalyze fission of the membrane pit's neck (the last step of endocytosis), not only significantly slowed endocytosis but also increased the synaptic vesicle diameter by as much as ∼40-64% at cultured hippocampal synapses. Furthermore, dynamin 1 knockout increased the size of membrane pits, the precursor for endocytic vesicle formation. These results suggest an important function of dynamin other than its well-known fission function - control of vesicle size at the pit formation stage.
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Affiliation(s)
- Bo Shi
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States; Biological Sciences Graduate Program, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20740 United States
| | - Ying-Hui Jin
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States; Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Ave, Guangzhou 510515, China
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892 United States.
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Sun EW, Matusica D, Wattchow DA, McCluskey A, Robinson PJ, Keating DJ. Dynamin regulates L cell secretion in human gut. Mol Cell Endocrinol 2021; 535:111398. [PMID: 34274446 DOI: 10.1016/j.mce.2021.111398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 06/01/2021] [Accepted: 07/13/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND The mechanochemical enzyme dynamin mediates endocytosis and regulates neuroendocrine cell exocytosis. Enteroendocrine L cells co-secrete the anorectic gut hormones glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) postprandially and is a potential therapeutic target for metabolic diseases. In the present study, we aimed to determine if dynamin is implicated in human L cell secretion. METHODS Western blot was performed on the murine L cell line GLUTag. Static incubation of human colonic mucosae with activators and inhibitors of dynamin was carried out. GLP-1 and PYY contents of the secretion supernatants were assayed using ELISA. RESULTS AND CONCLUSION s: Both dynamin I and II are expressed in GLUTag cells. The dynamin activator Ryngo 1-23 evoked significant GLP-1 and PYY release from human colonic mucosae while the dynamin inhibitor Dynole 3-42 significantly inhibited release triggered by known L cell secretagogues. Thus, the cell signaling regulator dynamin is able to bi-directionally regulate L cell hormone secretion in the human gut and may represent a novel target for gastrointestinal-targeted metabolic drug development.
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Affiliation(s)
- Emily Wl Sun
- Flinders Health and Medical Research Institute, Flinders University, Bedford Park, SA, Australia
| | - Dusan Matusica
- Flinders Health and Medical Research Institute, Flinders University, Bedford Park, SA, Australia
| | | | - Adam McCluskey
- Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Philip J Robinson
- Cell Signalling Unit, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Damien J Keating
- Flinders Health and Medical Research Institute, Flinders University, Bedford Park, SA, Australia.
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Peng GE, Pessino V, Huang B, von Zastrow M. Spatial decoding of endosomal cAMP signals by a metastable cytoplasmic PKA network. Nat Chem Biol 2021; 17:558-566. [PMID: 33649598 PMCID: PMC8084946 DOI: 10.1038/s41589-021-00747-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 01/22/2021] [Indexed: 01/31/2023]
Abstract
G-protein-coupled receptor-regulated cAMP production from endosomes can specify signaling to the nucleus by moving the source of cAMP without changing its overall amount. How this is possible remains unknown because cAMP gradients dissipate over the nanoscale, whereas endosomes typically localize micrometers from the nucleus. We show that the key location-dependent step for endosome-encoded transcriptional control is nuclear entry of cAMP-dependent protein kinase (PKA) catalytic subunits. These are sourced from punctate accumulations of PKA holoenzyme that are densely distributed in the cytoplasm and titrated by global cAMP into a discrete metastable state, in which catalytic subunits are bound but dynamically exchange. Mobile endosomes containing activated receptors collide with the metastable PKA puncta and pause in close contact. We propose that these properties enable cytoplasmic PKA to act collectively like a semiconductor, converting nanoscale cAMP gradients generated from endosomes into microscale elevations of free catalytic subunits to direct downstream signaling.
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Affiliation(s)
- Grace E Peng
- Program in Cell Biology, University of California, San Francisco, San Francisco, CA, USA
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Veronica Pessino
- Graduate Program of Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Swab56 Corp. and Neurophotometrics Ltd, San Diego, CA, USA
| | - Bo Huang
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Mark von Zastrow
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA.
- Quantitative Biology Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
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Ferreira APA, Casamento A, Carrillo Roas S, Halff EF, Panambalana J, Subramaniam S, Schützenhofer K, Chan Wah Hak L, McGourty K, Thalassinos K, Kittler JT, Martinvalet D, Boucrot E. Cdk5 and GSK3β inhibit fast endophilin-mediated endocytosis. Nat Commun 2021; 12:2424. [PMID: 33893293 PMCID: PMC8065113 DOI: 10.1038/s41467-021-22603-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
Endocytosis mediates the cellular uptake of micronutrients and cell surface proteins. Fast Endophilin-mediated endocytosis, FEME, is not constitutively active but triggered upon receptor activation. High levels of growth factors induce spontaneous FEME, which can be suppressed upon serum starvation. This suggested a role for protein kinases in this growth factor receptor-mediated regulation. Using chemical and genetic inhibition, we find that Cdk5 and GSK3β are negative regulators of FEME. They antagonize the binding of Endophilin to Dynamin-1 and to CRMP4, a Plexin A1 adaptor. This control is required for proper axon elongation, branching and growth cone formation in hippocampal neurons. The kinases also block the recruitment of Dynein onto FEME carriers by Bin1. As GSK3β binds to Endophilin, it imposes a local regulation of FEME. Thus, Cdk5 and GSK3β are key regulators of FEME, licensing cells for rapid uptake by the pathway only when their activity is low.
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Affiliation(s)
- Antonio P A Ferreira
- Institute of Structural and Molecular Biology, University College London, London, UK
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alessandra Casamento
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Sara Carrillo Roas
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Els F Halff
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - James Panambalana
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Shaan Subramaniam
- Institute of Structural and Molecular Biology, University College London, London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK
| | - Kira Schützenhofer
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Laura Chan Wah Hak
- Institute of Structural and Molecular Biology, University College London, London, UK
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Kieran McGourty
- Institute of Structural and Molecular Biology, University College London, London, UK
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland
| | | | - Josef T Kittler
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK
| | | | - Emmanuel Boucrot
- Institute of Structural and Molecular Biology, University College London, London, UK.
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK.
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7
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Lyu S, Doroodchi A, Xing H, Sheng Y, DeAndrade MP, Yang Y, Johnson TL, Clemens S, Yokoi F, Miller MA, Xiao R, Li Y. BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome. Brain Struct Funct 2020; 225:1743-1760. [PMID: 32468214 DOI: 10.1007/s00429-020-02090-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 05/13/2020] [Indexed: 01/17/2023]
Abstract
Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.
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Affiliation(s)
- Shangru Lyu
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Atbin Doroodchi
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hong Xing
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Yi Sheng
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mark P DeAndrade
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Youfeng Yang
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Tracy L Johnson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Fumiaki Yokoi
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA
| | - Michael A Miller
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Rui Xiao
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Yuqing Li
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, College of Medicine, University of Florida, PO Box 100236, Gainesville, FL, 32610-0236, USA.
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Abstract
Membrane fusion and fission are indispensable parts of intracellular membrane recycling and transport. Electrophysiological techniques have been instrumental in discovering and studying fusion and fission pores, the key intermediates shared by both processes. In cells, electrical admittance measurements are used to assess in real time the dynamics of the pore conductance, reflecting the nanoscale transformations of the pore, simultaneously with membrane leakage. Here, we described how this technique is adapted to in vitro mechanistic analyses of membrane fission by dynamin 1 (Dyn1), the protein orchestrating membrane fission in endocytosis. We reconstitute the fission reaction using purified Dyn1 and biomimetic lipid membrane nanotubes of defined geometry. We provide a comprehensive protocol describing simultaneous measurements of the ionic conductance through the nanotube lumen and across the nanotube wall, enabling spatiotemporal correlation between the nanotube constriction by Dyn1, leading to fission and membrane leakage. We present examples of "leaky" and "tight" fission reactions, specify the resolution limits of our method, and discuss how our results support the hemi-fission conjecture.
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Affiliation(s)
- Pavel V Bashkirov
- Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ksenia V Chekashkina
- Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Anna V Shnyrova
- Department of Biochemistry and Molecular Biology, Biophysics Institute (CSIC, UPV/EHU), University of the Basque Country, Leioa, Spain
| | - Vadim A Frolov
- Department of Biochemistry and Molecular Biology, Biophysics Institute (CSIC, UPV/EHU), University of the Basque Country, Leioa, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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9
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Neumann S, Malik SS, Marcus-Samuels B, Eliseeva E, Jang D, Klubo-Gwiezdzinska J, Krieger CC, Gershengorn MC. Thyrotropin Causes Dose-dependent Biphasic Regulation of cAMP Production Mediated by G s and G i/o Proteins. Mol Pharmacol 2020; 97:2-8. [PMID: 31704717 PMCID: PMC6864415 DOI: 10.1124/mol.119.117382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/18/2019] [Indexed: 12/14/2022] Open
Abstract
The thyrotropin (TSH) receptor (TSHR) signals via G proteins of all four classes and β-arrestin 1. Stimulation of TSHR leads to increasing cAMP production that has been reported as a monotonic dose-response curve that plateaus at high TSH doses. In HEK 293 cells overexpressing TSHRs (HEK-TSHR cells), we found that TSHR activation exhibits an "inverted U-shaped dose-response curve" with increasing cAMP production at low doses of TSH and decreased cAMP production at high doses (>1 mU/ml). Since protein kinase A inhibition by H-89 and knockdown of β-arrestin 1 or β-arrestin 2 did not affect the decreased cAMP production at high TSH doses, we studied the roles of TSHR downregulation and of Gi/Go proteins. A high TSH dose (100 mU/ml) caused a 33% decrease in cell-surface TSHR. However, because inhibiting TSHR downregulation with combined expression of a dominant negative dynamin 1 and β-arrestin 2 knockdown had no effect, we concluded that downregulation is not involved in the biphasic cAMP response. Pertussis toxin, which inhibits activation of Gi/Go, abolished the biphasic response with no statistically significant difference in cAMP levels at 1 and 100 mU/ml TSH. Concordantly, co-knockdown of Gi/Go proteins increased cAMP levels stimulated by 100 mU/ml TSH from 55% to 73% of the peak level. These data show that biphasic regulation of cAMP production is mediated by Gs and Gi/Go at low and high TSH doses, respectively, which may represent a mechanism to prevent overstimulation in TSHR-expressing cells. SIGNIFICANCE STATEMENT: We demonstrate biphasic regulation of TSH-mediated cAMP production involving coupling of the TSH receptor (TSHR) to Gs at low TSH doses and to Gi/o at high TSH doses. We suggest that this biphasic cAMP response allows the TSHR to mediate responses at lower levels of TSH and that decreased cAMP production at high doses may represent a mechanism to prevent overstimulation of TSHR-expressing cells. This mechanism could prevent chronic stimulation of thyroid gland function.
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Affiliation(s)
- Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sarah S Malik
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Bernice Marcus-Samuels
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Elena Eliseeva
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Daesong Jang
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Joanna Klubo-Gwiezdzinska
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Christine C Krieger
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Marvin C Gershengorn
- Laboratory of Endocrinology and Receptor Biology (S.N., S.S.M., B.M.-S., E.E., D.J., C.C.K., M.C.G.) and Metabolic Disease Branch (J.K.-G.), National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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10
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Wang H, Yuan X, Sun Y, Mao X, Meng C, Tan L, Song C, Qiu X, Ding C, Liao Y. Infectious bronchitis virus entry mainly depends on clathrin mediated endocytosis and requires classical endosomal/lysosomal system. Virology 2018; 528:118-136. [PMID: 30597347 PMCID: PMC7111473 DOI: 10.1016/j.virol.2018.12.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 12/27/2022]
Abstract
Although several reports suggest that the entry of infectious bronchitis virus (IBV) depends on lipid rafts and low pH, the endocytic route and intracellular trafficking are unclear. In this study, we aimed to shed greater light on early steps in IBV infection. By using chemical inhibitors, RNA interference, and dominant negative mutants, we observed that lipid rafts and low pH was indeed required for virus entry; IBV mainly utilized the clathrin mediated endocytosis (CME) for entry; GTPase dynamin 1 was involved in virus containing vesicle scission; and the penetration of IBV into cells led to active cytoskeleton rearrangement. By using R18 labeled virus, we found that virus particles moved along with the classical endosome/lysosome track. Functional inactivation of Rab5 and Rab7 significantly inhibited IBV infection. Finally, by using dual R18/DiOC labeled IBV, we observed that membrane fusion was induced after 1 h.p.i. in late endosome/lysosome. Intact lipid rafts is involved in IBV entry. Low pH in intracyplasmic vesicles is required for IBV entry. IBV penetrates cells via clathrin mediated endocytosis. IBV moves along with the classical endosome/lysosome track, finally fuses with late endosome/lysosome.
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Affiliation(s)
- Huan Wang
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Xiao Yuan
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Yingjie Sun
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Xiang Mao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Chunchun Meng
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Lei Tan
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Cuiping Song
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Xusheng Qiu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Chan Ding
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China.
| | - Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China.
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11
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Yang Y, Ma J, Lin D. [Effect of dynamin-related protein 1 in rats with myocardial ischemia/reperfusion injury]. Zhonghua Wei Zhong Bing Ji Jiu Yi Xue 2017; 29:902-906. [PMID: 29017650 DOI: 10.3760/cma.j.issn.2095-4352.2017.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the protective effect of dynamin-related protein 1 (Drp1) in rats with myocardial ischemia/reperfusion injury (IRI). METHODS Twenty-four healthy male Wistar rats were randomly divided into three groups (n = 8 each): sham group, IRI model group, and Drp1 inhibitor group. The left anterior descending branch of coronary artery was ligated to produce myocardial ischemia for 30 minutes and reperfusion injury model. Sham group was received only threading without ligation. The Drp1 inhibitor group was injected with 1.2 mg/kg mitochondrial division inhibitor 1 (mdivi-1) at 15 minutes before operation. At 3 hours after reperfusion, hemodynamics, serum myocardial enzymes, mitochondrial membrane potential (MMP), hydrogen peroxide (H2O2), reactive oxygen species (ROS) and ATP production were measured in rats. The myocardial tissues were harvested for the determination of the area at risk (AAR) and the infarct area (AI), and the ratio of AI/AAR was calculated. The expression of Drp1 and cytochrome C (Cyt C) was determined by Western Blot. RESULTS Compared with the sham group, the left ventricular end diastolic pressure (LVEDP), cardiac troponin I (cTnI), MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH), AI/AAR, H2O2, ROS, protein expression of Drp1 and Cyt C were significantly increased, left ventricular end systolic pressure (LVESP), ejection fraction (EF), fractional shortening (FS), MMP, ATP generation, expression of mitochondrial Cyt C were significantly decreased in IRI model group. Compared with IRI model group, LVEDP was significantly decreased in Drp1 inhibitor group [mmHg (1 mmHg = 0.133 kPa): 8.83±1.20 vs. 16.48±1.80], LVESP, EF, FS were significantly increased [LVESP (mmHg): 116.80±9.78 vs. 87.80±8.82, EF: 0.78±0.11 vs. 0.58±0.07, FS: (48.6±4.1)% vs. (32.4±3.2)%]; myocardial enzymes, H2O2 and ROS were significantly decreased in Drp1 inhibitor group [cTnI (ng/L): 31.9±8.8 vs. 49.2±13.7, CK-MB (U/L): 4.83±1.30 vs. 7.48±2.20, LDH (U/L): 1 327.80±280.20 vs. 1 858.80±324.80, H2O2: 6.40±1.40 vs. 8.90±1.50, ROS: 41 916.3±6 295.3 vs. 65 182.6±3 777.8], AI/AAR was significantly decreased (0.38±0.01 vs. 0.62±0.01), MMP and ATP were significantly increased [MMP: 0.78±0.13 vs. 0.38±0.07, ATP (μmol/g): 150.8±12.3 vs. 103.7±8.4], the expression of Drp1 was significantly decreased (0.50±0.02 vs. 0.79±0.05), expression of mitochondria Cyt C was significantly increased (0.64±0.04 vs. 0.21±0.01), and expression of cytoplasmic Cyt C was significantly decreased (0.48±0.03 vs. 0.78±0.04), and the differences were statistically significant (all P < 0.05). CONCLUSIONS Mitochondrial fission was excessively high during IRI, and its function was significantly decreased. Drp1 inhibitor could inhibit the division of mitochondria, and improve its function and cardiac function.
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Affiliation(s)
- Yanli Yang
- Department of Anesthesiology Center, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China. Corresponding author: Ma Jun,
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12
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Tham DKL, Joshi B, Moukhles H. Aquaporin-4 Cell-Surface Expression and Turnover Are Regulated by Dystroglycan, Dynamin, and the Extracellular Matrix in Astrocytes. PLoS One 2016; 11:e0165439. [PMID: 27788222 PMCID: PMC5082936 DOI: 10.1371/journal.pone.0165439] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/11/2016] [Indexed: 11/19/2022] Open
Abstract
The water-permeable channel aquaporin-4 (AQP4) is highly expressed in perivascular astrocytes of the mammalian brain and represents the major conduit for water across the blood-brain barrier. Within these cells, AQP4 is found in great quantities at perivascular endfoot sites but is detected in lesser amounts at the membrane domains within the brain parenchyma. We had previously established that this polarization was regulated by the interaction between dystroglycan (DG), an extracellular matrix receptor that is co-expressed with AQP4, and the laminin that is contained within the perivascular basal lamina. In the present study, we have attempted to describe the mechanisms that underlie this regulation, using primary astrocyte cultures. Via biotinylation, we found that the cell-surface expression of AQP4 is DG-dependent and is potentiated by laminin. We also determined that this laminin-dependent increase occurs not through an upregulation of total AQP4 levels, but rather from a redirection of AQP4 from an intracellular, EEA-1-associated pool to the cell surface. We then demonstrated an association between DG and dynamin and showed that dynamin functioned in conjunction with clathrin to regulate surface AQP4 amounts. Furthermore, we observed that DG preferentially binds to the inactive forms of dynamin, suggesting that this interaction was inhibitory for AQP4 endocytosis. Finally, we showed that laminin selectively upregulates the cell-surface expression of the M23 isoform of AQP4. Our data therefore indicate that the dual interation of DG with laminin and dynamin is involved in the regulation of AQP4 internalization, leading to its asymmetric enrichment at perivascular astrocyte endfeet.
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Affiliation(s)
- Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bharat Joshi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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13
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Krishnan S, Collett M, Robinson PJ. SH3 Domains Differentially Stimulate Distinct Dynamin I Assembly Modes and G Domain Activity. PLoS One 2015; 10:e0144609. [PMID: 26659814 PMCID: PMC4687643 DOI: 10.1371/journal.pone.0144609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 11/20/2015] [Indexed: 11/19/2022] Open
Abstract
Dynamin I is a highly regulated GTPase enzyme enriched in nerve terminals which mediates vesicle fission during synaptic vesicle endocytosis. One regulatory mechanism involves its interactions with proteins containing Src homology 3 (SH3) domains. At least 30 SH3 domain-containing proteins bind dynamin at its proline-rich domain (PRD). Those that stimulate dynamin activity act by promoting its oligomerisation. We undertook a systematic parallel screening of 13 glutathione-S-transferase (GST)-tagged endocytosis-related SH3 domains on dynamin binding, GTPase activity and oligomerisation. No correlation was found between dynamin binding and their potency to stimulate GTPase activity. There was limited correlation between the extent of their ability to stimulate dynamin activity and the level of oligomerisation, indicating an as yet uncharacterised allosteric coupling of the PRD and G domain. We examined the two variants, dynamin Iab and Ibb, which differ in the alternately splice middle domain α2 helix. They responded differently to the panel of SH3s, with the extent of stimulation between the splice variants varying greatly between the SH3s. This study reveals that SH3 binding can act as a heterotropic allosteric regulator of the G domain via the middle domain α2 helix, suggesting an involvement of this helix in communicating the PRD-mediated allostery. This indicates that SH3 binding both stabilises multiple conformations of the tetrameric building block of dynamin, and promotes assembly of dynamin-SH3 complexes with distinct rates of GTP hydrolysis.
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Affiliation(s)
- Sai Krishnan
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia
| | - Michael Collett
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia
| | - Phillip J. Robinson
- Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia
- * E-mail:
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Asinof SK, Sukoff Rizzo SJ, Buckley AR, Beyer BJ, Letts VA, Frankel WN, Boumil RM. Independent Neuronal Origin of Seizures and Behavioral Comorbidities in an Animal Model of a Severe Childhood Genetic Epileptic Encephalopathy. PLoS Genet 2015; 11:e1005347. [PMID: 26125563 PMCID: PMC4488318 DOI: 10.1371/journal.pgen.1005347] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 06/09/2015] [Indexed: 01/01/2023] Open
Abstract
The childhood epileptic encephalopathies (EE’s) are seizure disorders that broadly impact development including cognitive, sensory and motor progress with severe consequences and comorbidities. Recently, mutations in DNM1 (dynamin 1) have been implicated in two EE syndromes, Lennox-Gastaut Syndrome and Infantile Spasms. Dnm1 encodes dynamin 1, a large multimeric GTPase necessary for activity-dependent membrane recycling in neurons, including synaptic vesicle endocytosis. Dnm1Ftfl or “fitful” mice carry a spontaneous mutation in the mouse ortholog of DNM1 and recapitulate many of the disease features associated with human DNM1 patients, providing a relevant disease model of human EE’s. In order to examine the cellular etiology of seizures and behavioral and neurological comorbidities, we engineered a conditional Dnm1Ftfl mouse model of DNM1 EE. Observations of Dnm1Ftfl/flox mice in combination with various neuronal subpopulation specific cre strains demonstrate unique seizure phenotypes and clear separation of major neurobehavioral comorbidities from severe seizures associated with the germline model. This demonstration of pleiotropy suggests that treating seizures per se may not prevent severe comorbidity observed in EE associated with dynamin-1 mutations, and is likely to have implications for other genetic forms of EE. Childhood epilepsy syndromes, such as the early epileptic encephalopathies (EE’s) encompass seizure disorders that manifest early and negatively impact or completely block developmental progression. Recently, mutations in DNM1 (dynamin 1) have been implicated in two EE syndromes, Lennox-Gastaut Syndrome and Infantile Spasms. Dynamin 1 is a large multimeric protein that is critical for electro-chemical communication between neurons. To understand the relationship between severe seizures and the cognitive and behavioral developmental outcomes in DNM1 patients, we focus on “fitful” mice that carry a mutation in the dynamin 1 gene. Fitful mice have an EE disorder that is highly reminiscent of the documented human patients. Here, we describe genetic manipulations in the mice that allow us to determine that the seizure activity has independent cellular origins from the developmental and behavioral consequences. This separation confirms that the seizures do not cause the severe developmental delay and abnormal behaviors in this animal model and further suggests that any treatments aimed at controlling the seizures per se may not be effective for some of the most acute neurobehavioral symptoms in these patients.
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Affiliation(s)
- Samuel K. Asinof
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Alexandra R. Buckley
- Biomedical Sciences Graduate Program, University of California, San Diego, San Diego, California, United States of America
| | - Barbara J. Beyer
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Verity A. Letts
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Wayne N. Frankel
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Rebecca M. Boumil
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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15
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Calabrese B, Halpain S. Differential targeting of dynamin-1 and dynamin-3 to nerve terminals during chronic suppression of neuronal activity. Mol Cell Neurosci 2015; 68:36-45. [PMID: 25827095 DOI: 10.1016/j.mcn.2015.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/17/2015] [Accepted: 03/24/2015] [Indexed: 01/14/2023] Open
Abstract
Neurons express three closely related dynamin genes. Dynamin 1 has long been implicated in the regulation of synaptic vesicle recycling in nerve terminals, and dynamins 2 and 3 were more recently shown also to contribute to synaptic vesicle recycling in specific and distinguishable ways. In cultured hippocampal neurons we found that chronic suppression of spontaneous network activity differentially regulated the targeting of endogenous dynamins 1 and 3 to nerve terminals, while dynamin 2 was unaffected. Specifically, when neural activity was chronically silenced for 1-2weeks by tetrodotoxin (TTX), the clustering of dynamin 1 at nerve terminals was reduced, while the clustering of dynamin 3 significantly increased. Moreover, dynamin 3 clustering was induced within hours by the sustained blockade of AMPA receptors, suggesting that AMPA receptors may function to prevent Dyn3 accumulation within nerve terminals. Clustering of dynamin 3 was induced by an antagonist of the calcium-dependent protein phosphatase calcineurin, but was not dependent upon intact actin filaments. TTX-induced clustering of Dyn3 occurred with a markedly slower time-course than the previously described clustering of synapsin 1. Potassium-induced depolarization rapidly de-clustered dynamin 3 from nerve terminals within minutes. These results, which have implications for homeostatic synapse restructuring, indicate that the three dynamins have evolved different regulatory mechanisms for trafficking to and from nerve terminals in response to changes in neural activity.
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Affiliation(s)
- Barbara Calabrese
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States; Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, CA, United States.
| | - Shelley Halpain
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States; Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, CA, United States.
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16
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Liu XH, Geng Z, Yan J, Li T, Chen Q, Zhang QY, Chen ZY. Blocking GSK3β-mediated dynamin1 phosphorylation enhances BDNF-dependent TrkB endocytosis and the protective effects of BDNF in neuronal and mouse models of Alzheimer's disease. Neurobiol Dis 2014; 74:377-91. [PMID: 25484286 DOI: 10.1016/j.nbd.2014.11.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/26/2014] [Indexed: 01/19/2023] Open
Abstract
Endocytosis of tropomyosin related kinase B (TrkB) receptors has critical roles in brain-derived neurotrophic factor (BDNF) mediated signal transduction and biological function, however the mechanism that is governing TrkB endocytosis is still not completely understood. In this study, we showed that GSK3β, a key kinase in neuronal development and survival, could regulate TrkB endocytosis through phosphorylating dynamin1 (Dyn1) but not dynamin2 (Dyn2). Moreover, we found that beta-amyloid (Aβ) oligomer exposure could impair BDNF-dependent TrkB endocytosis and Akt activation through enhancing GSK3β activity in cultured hippocampal neurons, which suggested that BDNF-induced TrkB endocytosis and the subsequent signaling were impaired in neuronal model of Alzheimer's disease (AD). Notably, we found that inhibiting GSK3β phosphorylating Dyn1 by using TAT-Dyn1SpS could rescue the impaired TrkB endocytosis and Akt activation upon BDNF stimuli under Aβ exposure. Finally, TAT-Dyn1SpS could facilitate BDNF-mediated neuronal survival and cognitive enhancement in mouse models of AD. These results clarified a role of GSK3β in BDNF-dependent TrkB endocytosis and the subsequent signaling, and provided a potential new strategy by inhibiting GSK3β-induced Dyn1 phosphorylation for AD treatment.
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Affiliation(s)
- Xiang-Hua Liu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China
| | - Zhao Geng
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China
| | - Jing Yan
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China
| | - Ting Li
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China
| | - Qun Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China
| | - Qun-Ye Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Public Health, Shandong University Qilu Hospital, People's Republic of China
| | - Zhe-Yu Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China.
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Abstract
Dynamin 1–3 isoforms are known to be involved in endocytotic processes occurring during synaptic transmission. No data has directly linked dynamins yet with normal animal behavior. Here we show that dynamin pharmacologic inhibition markedly impairs hippocampal-dependent associative memory. Memory loss was associated with changes in synaptic function occurring during repetitive stimulation that is thought to be linked with memory induction. Synaptic fatigue was accentuated by dynamin inhibition. Moreover, dynamin inhibition markedly reduced long-term potentiation, post-tetanic potentiation, and neurotransmitter released during repetitive stimulation. Most importantly, the effect of dynamin inhibition onto memory and synaptic plasticity was due to a specific involvement of the dynamin 1 isoform, as demonstrated through a genetic approach with siRNA against this isoform to temporally block it. Taken together, these findings identify dynamin 1 as a key protein for modulation of memory and release evoked by repetitive activity.
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Affiliation(s)
- Mauro Fà
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Agnieszka Staniszewski
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Faisal Saeed
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Yitshak I. Francis
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America
- * E-mail:
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18
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Abstract
Dynamin proteins are involved in vesicle generation, providing mechanical force to excise newly formed vesicles from membranes of cellular compartments. In the brain, dynamin-1, dynamin-2, and dynamin-3 have been well studied; however, their function in the retina remains elusive. A retina-specific splice variant of dynamin-1 interacts with the photoreceptor-specific protein Tubby-like protein 1 (Tulp1), which when mutated causes an early onset form of autosomal recessive retinitis pigmentosa. Here, we investigated the role of the dynamins in the retina, using immunohistochemistry to localize dynamin-1, dynamin-2, and dynamin-3 and immunoprecipitation followed by mass spectrometry to explore dynamin-1 interacting proteins in mouse retina. Dynamin-2 is primarily confined to the inner segment compartment of photoreceptors, suggesting a role in outer segment protein transport. Dynamin-3 is present in the terminals of photoreceptors and dendrites of second-order neurons but is most pronounced in the inner plexiform layer where second-order neurons relay signals from photoreceptors. Dynamin-1 appears to be the dominant isoform in the retina and is present throughout the retina and in multiple compartments of the photoreceptor cell. This suggests that it may function in multiple cellular pathways. Surprisingly, dynamin-1 expression and localization did not appear to be disrupted in tulp1−/− mice. Immunoprecipitation experiments reveal that dynamin-1 associates primarily with proteins involved in cytoskeletal-based membrane dynamics. This finding is confirmed by western blot analysis. Results further implicate dynamin-1 in vesicular protein transport processes relevant to synaptic and post-Golgi pathways and indicate a possible role in photoreceptor stability.
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Affiliation(s)
- Gregory H Grossman
- Department of Ophthalmic Research, Cleveland Clinic Cole Eye Institute, Cleveland, Ohio
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Shnyrova AV, Bashkirov PV, Akimov SA, Pucadyil TJ, Zimmerberg J, Schmid SL, Frolov VA. Geometric catalysis of membrane fission driven by flexible dynamin rings. Science 2013; 339:1433-6. [PMID: 23520112 PMCID: PMC3980720 DOI: 10.1126/science.1233920] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Biological membrane fission requires protein-driven stress. The guanosine triphosphatase (GTPase) dynamin builds up membrane stress by polymerizing into a helical collar that constricts the neck of budding vesicles. How this curvature stress mediates nonleaky membrane remodeling is actively debated. Using lipid nanotubes as substrates to directly measure geometric intermediates of the fission pathway, we found that GTP hydrolysis limits dynamin polymerization into short, metastable collars that are optimal for fission. Collars as short as two rungs translated radial constriction to reversible hemifission via membrane wedging of the pleckstrin homology domains (PHDs) of dynamin. Modeling revealed that tilting of the PHDs to conform with membrane deformations creates the low-energy pathway for hemifission. This local coordination of dynamin and lipids suggests how membranes can be remodeled in cells.
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Affiliation(s)
- Anna V. Shnyrova
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| | - Pavel V. Bashkirov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Sergey A. Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | | | - Joshua Zimmerberg
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sandra L. Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Vadim A. Frolov
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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Zhang CL, Yin F, Yang ZQ, He F, Chen C, Jiang SJ, Peng J. [Expression of dynamin-1 and phosphor-dynamin-1 in the hippocampus of children and rats with mesial temporal lobe epilepsy]. Zhongguo Dang Dai Er Ke Za Zhi 2013; 15:133-137. [PMID: 23428130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To observe the expression of dynamin-1 and phosphor-dynamin-1 in the hippocampus of children and rats with mesial temporal lobe epilepsy (MTLE) and to investigate the roles of dynamin-1 and phosphor-dynamin-1 in the development of MTLE. METHODS Male Sprague-Dawley rats (aged 25 days) were randomly divided into acute control (AC), acute seizure (AS), latent control (LC), latent seizure (LS), chronic control (CC) and chronic spontaneous seizure (CS) groups. Lithium chloride-pilocarpine was used to induce a rat model of MTLE. The hippocampus samples of 5 children with a pathologically confirmed hippocampal sclerosis who received surgical operation were collected as a human model (HM) group, and the hippocampus samples of 4 dead children (without organic lesion of the hippocampus) were collected by autopsy as a human control (HC) group. The expression of dynamin-1 and phosphor-dynamin-1 in the hippocampus of children and rats with MTLE was measured by Western blot and immunohistochemistry. RESULTS The Western blot showed that the expression of phosphor-dynamin-1 was significantly lower in the AS and CS groups than in the corresponding control groups (AC and CC groups) (P<0.05). The expression of phosphor-dynamin-1 was significantly lower in the HM group than in the HC group (P<0.05). There were no significant differences in the expression of dynamin-1 among the AS, LS and CS groups and between the HM and HC groups (P>0.05). The immunohistochemical results showed that phosphor-dynamin-1 was highly expressed in the cytoplasm of hippocampal neurons of AC, CC and HC groups, but its expression was significantly reduced in the AS, CS and HM groups (P<0.05). CONCLUSIONS The expression of phosphor-dynamin-1, not dynamin-1, is downregulated in the hippocampus of children and rats with MTLE during seizures, which suggests that the phosphorylation/dephosphorylation of dynamin-1 may be involved in the development of MTLE.
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Affiliation(s)
- Ci-Liu Zhang
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, China
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Abstract
Endocytosis is a fundamental process in signaling and membrane trafficking. The formation of vesicles at the plasma membrane is mediated by the G protein dynamin that catalyzes the final fission step, the actin cytoskeleton, and proteins that sense or induce membrane curvature. One such protein, the F-BAR domain-containing protein pacsin, contributes to this process and has been shown to induce a spectrum of membrane morphologies, including tubules and tube constrictions in vitro. Full-length pacsin isoform 1 (pacsin-1) has reduced activity compared to its isolated F-BAR domain, implicating an inhibitory role for its C-terminal Src homology 3 (SH3) domain. Here we show that the autoinhibitory, intramolecular interactions in pacsin-1 can be released upon binding to the entire proline-rich domain (PRD) of dynamin-1, resulting in potent membrane deformation activity that is distinct from the isolated F-BAR domain. Most strikingly, we observe the generation of small, homogenous vesicles with the activated protein complex under certain experimental conditions. In addition, liposomes prepared with different methods yield distinct membrane deformation morphologies of BAR domain proteins and apparent activation barriers to pacsin-1's activity. Theoretical free energy calculations suggest bimodality of the protein-membrane system as a possible source for the different outcomes, which could account for the coexistence of energetically equivalent membrane structures induced by BAR domain-containing proteins in vitro. Taken together, our results suggest a versatile role for pacsin-1 in sculpting cellular membranes that is likely dependent both on protein structure and membrane properties.
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Affiliation(s)
- Shih Lin Goh
- Department of Molecular Medicine, Cornell University, Ithaca, New York, United States of America
| | - Qi Wang
- Department of Molecular Medicine, Cornell University, Ithaca, New York, United States of America
| | - Laura J. Byrnes
- Department of Molecular Medicine, Cornell University, Ithaca, New York, United States of America
| | - Holger Sondermann
- Department of Molecular Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Zhu L, Su M, Lucast L, Liu L, Netzer WJ, Gandy SE, Cai D. Dynamin 1 regulates amyloid generation through modulation of BACE-1. PLoS One 2012; 7:e45033. [PMID: 23024787 PMCID: PMC3443198 DOI: 10.1371/journal.pone.0045033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 08/11/2012] [Indexed: 11/25/2022] Open
Abstract
Background Several lines of investigation support the notion that endocytosis is crucial for Alzheimer’s disease (AD) pathogenesis. Substantial evidence have already been reported regarding the mechanisms underlying amyloid precursor protein (APP) traffic, but the regulation of beta-site APP-Cleaving Enzyme 1 (BACE-1) distribution among endosomes, TGN and plasma membrane remains unclear. Dynamin, an important adaptor protein that controls sorting of many molecules, has recently been associated with AD but its functions remain controversial. Here we studied possible roles for dynamin 1 (dyn1) in Aβ biogenesis. Principal Findings We found that genetic perturbation of dyn1 reduces both secreted and intracellular Aβ levels in cell culture. There is a dramatic reduction in BACE-1 cleavage products of APP (sAPPβ and βCTF). Moreover, dyn1 knockdown (KD) leads to BACE-1 redistribution from the Golgi-TGN/endosome to the cell surface. There is an increase in the amount of surface holoAPP upon dyn1 KD, with resultant elevation of α–secretase cleavage products sAPPα and αCTF. But no changes are seen in the amount of nicastrin (NCT) or PS1 N-terminal fragment (NTF) at cell surface with dyn1 KD. Furthermore, treatment with a selective dynamin inhibitor Dynasore leads to similar reduction in βCTF and Aβ levels, comparable to changes with BACE inhibitor treatment. But combined inhibition of BACE-1 and dyn1 does not lead to further reduction in Aβ, suggesting that the Aβ-lowering effects of dynamin inhibition are mainly mediated through regulation of BACE-1 internalization. Aβ levels in dyn1−/− primary neurons, as well as in 3-month old dyn1 haploinsufficient animals with AD transgenic background are consistently reduced when compared to their wildtype counterparts. Conclusions In summary, these data suggest a previously unknown mechanism by which dyn1 affects amyloid generation through regulation of BACE-1 subcellular localization and therefore its enzymatic activities.
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Affiliation(s)
- Li Zhu
- Department of Neurology and Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- James J. Peters Veterans Affairs Medical Center, Bronx, New York, United States of America
| | - Meng Su
- Department of Neurology and Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Pathology, John Hopkins Medical Center, Baltimore, Maryland, United States of America
| | - Louise Lucast
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Lijuan Liu
- Department of Cell Biology and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - William J. Netzer
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, New York, United States of America
| | - Samuel E. Gandy
- Department of Neurology and Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- James J. Peters Veterans Affairs Medical Center, Bronx, New York, United States of America
| | - Dongming Cai
- Department of Neurology and Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- James J. Peters Veterans Affairs Medical Center, Bronx, New York, United States of America
- * E-mail:
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DeAndrade MP, Zhang L, Doroodchi A, Yokoi F, Cheetham CC, Chen HX, Roper SN, Sweatt JD, Li Y. Enhanced hippocampal long-term potentiation and fear memory in Btbd9 mutant mice. PLoS One 2012; 7:e35518. [PMID: 22536397 PMCID: PMC3334925 DOI: 10.1371/journal.pone.0035518] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 03/17/2012] [Indexed: 01/01/2023] Open
Abstract
Polymorphisms in BTBD9 have recently been associated with higher risk of restless legs syndrome (RLS), a neurological disorder characterized by uncomfortable sensations in the legs at rest that are relieved by movement. The BTBD9 protein contains a BTB/POZ domain and a BACK domain, but its function is unknown. To elucidate its function and potential role in the pathophysiology of RLS, we generated a line of mutant Btbd9 mice derived from a commercial gene-trap embryonic stem cell clone. Btbd9 is the mouse homolog of the human BTBD9. Proteins that contain a BTB/POZ domain have been reported to be associated with synaptic transmission and plasticity. We found that Btbd9 is naturally expressed in the hippocampus of our mutant mice, a region critical for learning and memory. As electrophysiological characteristics of CA3-CA1 synapses of the hippocampus are well characterized, we performed electrophysiological recordings in this region. The mutant mice showed normal input-output relationship, a significant impairment in pre-synaptic activity, and an enhanced long-term potentiation. We further performed an analysis of fear memory and found the mutant mice had an enhanced cued and contextual fear memory. To elucidate a possible molecular basis for these enhancements, we analyzed proteins that have been associated with synaptic plasticity. We found an elevated level of dynamin 1, an enzyme associated with endocytosis, in the mutant mice. These results suggest the first identified function of Btbd9 as being involved in regulating synaptic plasticity and memory. Recent studies have suggested that enhanced synaptic plasticity, analogous to what we have observed, in other regions of the brain could enhance sensory perception similar to what is seen in RLS patients. Further analyses of the mutant mice will help shine light on the function of BTBD9 and its role in RLS.
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Affiliation(s)
- Mark P. DeAndrade
- Interdisciplinary Program in Biomedical Sciences, College of Medicine, University of Florida, Gainesville, Florida, United States of America
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Li Zhang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Atbin Doroodchi
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Fumiaki Yokoi
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Chad C. Cheetham
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Huan-Xin Chen
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Steven N. Roper
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - J. David Sweatt
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yuqing Li
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Murakami N, Bolton DC, Kida E, Xie W, Hwang YW. Phosphorylation by Dyrk1A of clathrin coated vesicle-associated proteins: identification of the substrate proteins and the effects of phosphorylation. PLoS One 2012; 7:e34845. [PMID: 22514676 PMCID: PMC3325943 DOI: 10.1371/journal.pone.0034845] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 03/08/2012] [Indexed: 11/26/2022] Open
Abstract
Dyrk1A phosphorylated multiple proteins in the clathrin-coated vesicle (CCV) preparations obtained from rat brains. Mass spectrometric analysis identified MAP1A, MAP2, AP180, and α- and β-adaptins as the phosphorylated proteins in the CCVs. Each protein was subsequently confirmed by [(32)P]-labeling and immunological methods. The Dyrk1A-mediated phosphorylation released the majority of MAP1A and MAP2 and enhanced the release of AP180 and adaptin subunits from the CCVs. Furthermore, Dyrk1A displaced adaptor proteins physically from CCVs in a kinase-concentration dependent manner. The clathrin heavy chain release rate, in contrast, was not affected by Dyrk1A. Surprisingly, the Dyrk1A-mediated phosphorylation of α- and β-adaptins led to dissociation of the AP2 complex, and released only β-adaptin from the CCVs. AP180 was phosphorylated by Dyrk1A also in the membrane-free fractions, but α- and β-adaptins were not. Dyrk1A was detected in the isolated CCVs and was co-localized with clathrin in neurons from mouse brain sections and from primary cultured rat hippocampus. Previously, we proposed that Dyrk1A inhibits the onset of clathrin-mediated endocytosis in neurons by phosphorylating dynamin 1, amphiphysin 1, and synaptojanin 1. Current results suggest that besides the inhibition, Dyrk1A promotes the uncoating process of endocytosed CCVs.
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Affiliation(s)
- Noriko Murakami
- Laboratory of Molecular Regulation, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America. . gov
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25
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Abstract
Zhang et al. (2012) and Rozas et al. (2012) in this issue of Neuron find that cysteine string protein α, a protein involved in neurodegeneration, regulates vesicle endocytosis via interaction with dynamin 1, which may participate in regulating synaptic transmission and possibly in maintaining synapses.
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Affiliation(s)
- Jiansong Sheng
- Synaptic Transmission Section, National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Rm. 2B-1012, Bethesda, MD 20892, USA
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Taylor MJ, Lampe M, Merrifield CJ. A feedback loop between dynamin and actin recruitment during clathrin-mediated endocytosis. PLoS Biol 2012; 10:e1001302. [PMID: 22505844 PMCID: PMC3323523 DOI: 10.1371/journal.pbio.1001302] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 02/23/2012] [Indexed: 12/14/2022] Open
Abstract
Clathrin-mediated endocytosis proceeds by a sequential series of reactions catalyzed by discrete sets of protein machinery. The final reaction in clathrin-mediated endocytosis is membrane scission, which is mediated by the large guanosine triophosphate hydrolase (GTPase) dynamin and which may involve the actin-dependent recruitment of N-terminal containing BIN/Amphiphysin/RVS domain containing (N-BAR) proteins. Optical microscopy has revealed a detailed picture of when and where particular protein types are recruited in the ∼20-30 s preceding scission. Nevertheless, the regulatory mechanisms and functions that underpin protein recruitment are not well understood. Here we used an optical assay to investigate the coordination and interdependencies between the recruitment of dynamin, the actin cytoskeleton, and N-BAR proteins to individual clathrin-mediated endocytic scission events. These measurements revealed that a feedback loop exists between dynamin and actin at sites of membrane scission. The kinetics of dynamin, actin, and N-BAR protein recruitment were modulated by dynamin GTPase activity. Conversely, acute ablation of actin dynamics using latrunculin-B led to a ∼50% decrease in the incidence of scission, an ∼50% decrease in the amplitude of dynamin recruitment, and abolished actin and N-BAR recruitment to scission events. Collectively these data suggest that dynamin, actin, and N-BAR proteins work cooperatively to efficiently catalyze membrane scission. Dynamin controls its own recruitment to scission events by modulating the kinetics of actin and N-BAR recruitment to sites of scission. Conversely actin serves as a dynamic scaffold that concentrates dynamin and N-BAR proteins at sites of scission.
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Affiliation(s)
| | - Marko Lampe
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Christien J. Merrifield
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- CNRS UPR3082, Laboratoire d'Enzymologie et de Biochimie Structurales, Gif-sur-Yvette Cedex, France
- * E-mail:
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Koutsopoulos OS, Koch C, Tosch V, Böhm J, North KN, Laporte J. Mild functional differences of dynamin 2 mutations associated to centronuclear myopathy and Charcot-Marie Tooth peripheral neuropathy. PLoS One 2011; 6:e27498. [PMID: 22096584 PMCID: PMC3214065 DOI: 10.1371/journal.pone.0027498] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 10/18/2011] [Indexed: 11/18/2022] Open
Abstract
The large GTPase dynamin 2 is a key player in membrane and cytoskeletal dynamics mutated in centronuclear myopathy (CNM) and Charcot-Marie Tooth (CMT) neuropathy, two discrete dominant neuromuscular disorders affecting skeletal muscle and peripheral nerves respectively. The molecular basis for the tissue-specific phenotypes observed and the physiopathological mechanisms linked to dynamin 2 mutations are not well established. In this study, we have analyzed the impact of CNM and CMT implicated dynamin 2 mutants using ectopic expression of four CNM and two CMT mutations, and patient fibroblasts harboring two dynamin 2 CNM mutations in established cellular processes of dynamin 2 action. Wild type and CMT mutants were seen in association with microtubules whereas CNM mutants lacked microtubules association and did not disrupt interphase microtubules dynamics. Most dynamin 2 mutants partially decreased clathrin-mediated endocytosis when ectopically expressed in cultured cells; however, experiments in patient fibroblasts suggested that endocytosis is overall not defective. Furthermore, CNM mutants were seen in association with enlarged clathrin stained structures whereas the CMT mutant constructs were associated with clathrin structures that appeared clustered, similar to the structures observed in Dnm1 and Dnm2 double knock-out cells. Other roles of dynamin 2 including its interaction with BIN1 (amphiphysin 2), and its function in Golgi maintenance and centrosome cohesion were not significantly altered. Taken together, these mild functional defects are suggestive of differences between CMT and CNM disease-causing dynamin 2 mutants and suggest that a slight impairment in clathrin-mediated pathways may accumulate over time to foster the respective human diseases.
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Affiliation(s)
- Olga S. Koutsopoulos
- Department of Translational Medecine, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U964, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Catherine Koch
- Department of Translational Medecine, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U964, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Valerie Tosch
- Department of Translational Medecine, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U964, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Johann Böhm
- Department of Translational Medecine, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U964, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Kathryn N. North
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia
- Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Australia
| | - Jocelyn Laporte
- Department of Translational Medecine, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Illkirch, France
- Inserm, U964, Illkirch, France
- CNRS, UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
- * E-mail:
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28
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Bodmer D, Ascaño M, Kuruvilla R. Isoform-specific dephosphorylation of dynamin1 by calcineurin couples neurotrophin receptor endocytosis to axonal growth. Neuron 2011; 70:1085-99. [PMID: 21689596 DOI: 10.1016/j.neuron.2011.04.025] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2011] [Indexed: 01/19/2023]
Abstract
Endocytic events are critical for neuronal survival in response to target-derived neurotrophic cues, but whether local axon growth is mediated by endocytosis-dependent signaling mechanisms remains unclear. Here, we report that Nerve Growth Factor (NGF) promotes endocytosis of its TrkA receptors and axon growth by calcineurin-mediated dephosphorylation of the endocytic GTPase dynamin1. Conditional deletion of calcineurin in sympathetic neurons disrupts NGF-dependent innervation of peripheral target tissues. Calcineurin signaling is required locally in sympathetic axons to support NGF-mediated growth in a manner independent of transcription. We show that calcineurin associates with dynamin1 via a PxIxIT interaction motif found only in specific dynamin1 splice variants. PxIxIT-containing dynamin1 isoforms colocalize with surface TrkA receptors, and their phosphoregulation is selectively required for NGF-dependent TrkA internalization and axon growth in sympathetic neurons. Thus, NGF-dependent phosphoregulation of dynamin1 is a critical event coordinating neurotrophin receptor endocytosis and axonal growth.
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Affiliation(s)
- Daniel Bodmer
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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Abstract
Our previous genetic and proteomic studies demonstrated that dynamin 1 is significantly associated with nicotine dependence (ND) in human smokers and its expression is highly modulated by nicotine in the brains of animals. To provide further molecular evidence for the involvement of dynamin 1 in the etiology of ND, we investigated the regulatory effect of nicotine on the expression of dynamin 1 using both in vivo and in vitro approaches. With quantitative real-time RT-PCR, we found that dynamin 1 mRNA was significantly downregulated, by 30%, 31%, and 38%, in the striatum, hippocampus, and medial basal hypothalamus (MBH), respectively, of nicotine-treated rats (P<0.01 for all three regions). Further, dynamin 1 protein was downregulated by nicotine in the ventral tegmental area (VTA: 39.5%; P<0.01), hippocampus (13.4%, P<0.05), MBH (24.6%, P<0.01), and amygdala (15.7%, P<0.05). We also determined the effect of nicotine on human SH-SY5Y cells and found that dynamin 1 mRNA was significantly down-regulated by nicotine after treatment (51.4%; P<0.01), and a consistent decrease in the amount of the protein was also observed (36.6%; P<0.05). Taken together, our findings provide further molecular evidence for the involvement of dynamin 1 in the etiology of ND.
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Affiliation(s)
- Qing Xu
- Institute of Biological Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22911, USA
| | - Ming D. Li
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22911, USA
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30
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Mondin M, Carta M, Normand E, Mulle C, Coussen F. Profilin II regulates the exocytosis of kainate glutamate receptors. J Biol Chem 2010; 285:40060-71. [PMID: 20937818 PMCID: PMC3000988 DOI: 10.1074/jbc.m110.140442] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 10/01/2010] [Indexed: 11/06/2022] Open
Abstract
The trafficking of ionotropic glutamate receptors to and from synaptic sites is regulated by proteins that interact with their cytoplasmic C-terminal domain. Profilin IIa (PfnIIa), an actin-binding protein expressed in the brain and recruited to synapses in an activity-dependent manner, was shown previously to interact with the C-terminal domain of the GluK2b subunit splice variant of kainate receptors (KARs). Here, we characterize this interaction and examine the role of PfnIIa in the regulation of KAR trafficking. PfnIIa directly and specifically binds to the C-terminal domain of GluK2b through a diproline motif. Expression of PfnIIa in transfected COS-7 cells and in cultured hippocampal neurons from PfnII-deficient mice decreases the level of extracellular of homomeric GluK2b as well as heteromeric GluK2a/GluK2b KARs. Our data suggest a novel mechanism by which PfnIIa exerts a dual role on the trafficking of KARs, by a generic inhibition of clathrin-mediated endocytosis through its interaction with dynamin-1, and by controlling KARs exocytosis through a direct and specific interaction with GluK2b.
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Affiliation(s)
- Magali Mondin
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Mario Carta
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Elisabeth Normand
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Christophe Mulle
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Françoise Coussen
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
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Boumil RM, Letts VA, Roberts MC, Lenz C, Mahaffey CL, Zhang ZW, Moser T, Frankel WN. A missense mutation in a highly conserved alternate exon of dynamin-1 causes epilepsy in fitful mice. PLoS Genet 2010; 6. [PMID: 20700442 PMCID: PMC2916854 DOI: 10.1371/journal.pgen.1001046] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 07/02/2010] [Indexed: 11/19/2022] Open
Abstract
Dynamin-1 (Dnm1) encodes a large multimeric GTPase necessary for activity-dependent membrane recycling in neurons, including synaptic vesicle endocytosis. Mice heterozygous for a novel spontaneous Dnm1 mutation—fitful—experience recurrent seizures, and homozygotes have more debilitating, often lethal seizures in addition to severe ataxia and neurosensory deficits. Fitful is a missense mutation in an exon that defines the DNM1a isoform, leaving intact the alternatively spliced exon that encodes DNM1b. The expression of the corresponding alternate transcripts is developmentally regulated, with DNM1b expression highest during early neuronal development and DNM1a expression increasing postnatally with synaptic maturation. Mutant DNM1a does not efficiently self-assemble into higher order complexes known to be necessary for proper dynamin function, and it also interferes with endocytic recycling in cell culture. In mice, the mutation results in defective synaptic transmission characterized by a slower recovery from depression after trains of stimulation. The DNM1a and DNM1b isoform pair is highly conserved in vertebrate evolution, whereas invertebrates have only one isoform. We speculate that the emergence of more specialized forms of DNM1 may be important in organisms with complex neuronal function. Epilepsy, a group of chronic disorders characterized by recurrent seizures, results from abnormal, synchronized neuronal activity in the brain. The mouse represents a powerful system to study novel mutations that model neurological disease, including epilepsy. Here we describe a new mouse mutation (“fitful”) in the gene encoding dynamin-1. Fitful mice have recurrent seizures and other neurological defects, including impaired hearing. Dynamin-1 is very well studied, but has yet to be linked to neurological disease. Dynamin-1 is a large multimeric enzyme that functions in membrane fission, primarily of vesicles after they release neurotransmitter at neuronal synapses. Fitful occurs in the region of dynamin-1 that is important for self-assembly of single dynamin subunits into the multimers required for enzymatic function. We show that fitful interferes with dynamin-1 self-assembly and with endocytosis. Moreover, the mutation resides in one of two alternate forms of dynamin-1 and affects what may be a necessary shift during brain development, with the expression of the mutated form being higher after maturation in fitful mice. This particular genetic specialization is unique to vertebrate dynamin. We speculate that specialized forms of dynamin-1 are important for modifying the self-assembly process to meet the demands complex brain activity in higher organisms.
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Cao Y, Ravid R, Guan ZZ. [Changes in expression of synaptic proteins in brains of patients with Alzheimer's disease]. Zhonghua Bing Li Xue Za Zhi 2009; 38:833-834. [PMID: 20193460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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33
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Liu YW, Surka MC, Schroeter T, Lukiyanchuk V, Schmid SL. Isoform and splice-variant specific functions of dynamin-2 revealed by analysis of conditional knock-out cells. Mol Biol Cell 2008; 19:5347-59. [PMID: 18923138 PMCID: PMC2592655 DOI: 10.1091/mbc.e08-08-0890] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 10/01/2008] [Accepted: 10/03/2008] [Indexed: 01/05/2023] Open
Abstract
Dynamin (Dyn) is a multifunctional GTPase implicated in several cellular events, including endocytosis, intracellular trafficking, cell signaling, and cytokinesis. The mammalian genome encodes three isoforms, Dyn1, Dyn2, and Dyn3, and several splice variants of each, leading to the suggestion that distinct isoforms and/or distinct splice variants might mediate distinct cellular functions. We generated a conditional Dyn2 KO cell line and performed knockout and reconstitution experiments to explore the isoform- and splice variant specific cellular functions of ubiquitously expressed Dyn2. We find that Dyn2 is required for clathrin-mediated endocytosis (CME), p75 export from the Golgi, and PDGF-stimulated macropinocytosis and cytokinesis, but not for other endocytic pathways. Surprisingly, CME and p75 exocytosis were efficiently rescued by reintroduction of Dyn2, but not Dyn1, suggesting that these two isoforms function differentially in vesicular trafficking in nonneuronal cells. Both isoforms rescued macropinocytosis and cytokinesis, suggesting that dynamin function in these processes might be mechanistically distinct from its role in CME. Although all four Dyn2 splice variants could equally restore CME, Dyn2ba and -bb were more effective at restoring p75 exocytosis. This splice variant specificity correlated with their differential targeting to the Golgi. These studies reveal isoform and splice-variant specific functions for Dyn2.
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Affiliation(s)
- Ya-Wen Liu
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Mark C. Surka
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Thomas Schroeter
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Vasyl Lukiyanchuk
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Sandra L. Schmid
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
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Pountney DL, Raftery MJ, Chegini F, Blumbergs PC, Gai WP. NSF, Unc-18-1, dynamin-1 and HSP90 are inclusion body components in neuronal intranuclear inclusion disease identified by anti-SUMO-1-immunocapture. Acta Neuropathol 2008; 116:603-14. [PMID: 18836734 DOI: 10.1007/s00401-008-0437-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 09/11/2008] [Accepted: 09/16/2008] [Indexed: 11/24/2022]
Abstract
Neuronal intranuclear inclusion disease, a progressive ataxia that may be familial or sporadic, is characterized by numerous neuronal intranuclear inclusion bodies similar to those found in polyglutamine repeat diseases. Previously, we found that the intranuclear inclusion bodies are intensely immunopositive for SUMO-1, a protein which covalently conjugates to other proteins in a similar way to ubiquitin. To identify the SUMO-1-associated proteins in the inclusion bodies, we isolated intranuclear inclusion bodies from fresh, frozen brain tissue of a case with familial neuronal intranuclear inclusion disease and solubilized the proteins. SUMO-1-associated inclusion body proteins were then immunocaptured using an anti-SUMO-1 antibody. The proteins, NSF, dynamin-1 and Unc-18-1 (rbSEC1), involved in membrane trafficking of proteins, and the chaperone HSP90, were identified following anti-SUMO-1-immunocapture by using tandem mass spectrometry and database searching. Immunohistochemistry of brain sections and crude brain homogenates of three cases of familial neuronal intranuclear inclusion disease confirmed the presence of these proteins in intranuclear inclusions.
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Affiliation(s)
- Dean L Pountney
- School of Medical Science, Griffith Institute of Health and Medical Research, Griffith University, Gold Coast Campus, Queensland, QLD, 4222, Australia.
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Cunha FM, Berti DA, Ferreira ZS, Klitzke CF, Markus RP, Ferro ES. Intracellular peptides as natural regulators of cell signaling. J Biol Chem 2008; 283:24448-59. [PMID: 18617518 PMCID: PMC3259820 DOI: 10.1074/jbc.m801252200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 06/20/2008] [Indexed: 12/25/2022] Open
Abstract
Protein degradation by the ubiquitin proteasome system releases large amounts of oligopeptides within cells. To investigate possible functions for these intracellularly generated oligopeptides, we fused them to a cationic transactivator peptide sequence using reversible disulfide bonds, introduced them into cells, and analyzed their effect on G protein-coupled receptor (GPCR) signal transduction. A mixture containing four of these peptides (20-80 microm) significantly inhibited the increase in the extracellular acidification response triggered by angiotensin II (ang II) in CHO-S cells transfected with the ang II type 1 receptor (AT1R-CHO-S). Subsequently, either alone or in a mixture, these peptides increased luciferase gene transcription in AT1R CHO-S cells stimulated with ang II and in HEK293 cells treated with isoproterenol. These peptides without transactivator failed to affect GPCR cellular responses. All four functional peptides were shown in vitro to competitively inhibit the degradation of a synthetic substrate by thimet oligopeptidase. Overexpression of thimet oligopeptidase in both CHO-S and HEK293 cells was sufficient to reduce luciferase activation triggered by a specific GPCR agonist. Moreover, using individual peptides as baits in affinity columns, several proteins involved in GPCR signaling were identified, including alpha-adaptin A and dynamin 1. These results suggest that before their complete degradation, intracellular peptides similar to those generated by proteasomes can actively affect cell signaling, probably representing additional bioactive molecules within cells.
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Affiliation(s)
- Fernanda M. Cunha
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Denise A. Berti
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Zulma S. Ferreira
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Clécio F. Klitzke
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Regina P. Markus
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Emer S. Ferro
- Departments of Cell Biology and
Development and Physiology, Biomedical Science
Institute, University of São Paulo, São Paulo, SP 05508-900, the
Department of Biochemistry, Federal University
of São Paulo, São Paulo, SP 04044-020, and the
Center for Applied Toxinology, CAT/CEPID,
Butantan Institute, São Paulo, SP 05503-900, Brazil
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Abstract
AIMS One of the main causes of cardiovascular complications in diabetes is the hyperglycaemia-induced cell injury, and mitochondrial fission has been implicated in the apoptotic process. We investigated the role of mitochondrial fission in high glucose-induced cardiovascular cell injury. METHODS AND RESULTS We used several types of cultured mouse, rat, and bovine cells from the cardiovascular system, and evaluated mitochondrial morphology, reactive oxygen species (ROS) levels, and apoptotic parameters in sustained high glucose incubation. Adenoviral infection was used for the inhibition of the fission protein DLP1. We found that mitochondria were short and fragmented in cells incubated in sustained high glucose conditions. Under the same conditions, cellular ROS levels were high and cell death was increased. We demonstrated that the increased level of ROS causes mitochondrial permeability transition (MPT), phosphatidylserine exposure, cytochrome c release, and caspase activation in prolonged high glucose conditions. Importantly, maintaining tubular mitochondria by inhibiting mitochondrial fission in sustained high glucose conditions normalized cellular ROS levels and prevented the MPT and subsequent cell death. These results demonstrate that mitochondrial fragmentation is an upstream factor for ROS overproduction and cell death in prolonged high glucose conditions. CONCLUSION These findings indicate that the fission-mediated fragmentation of mitochondrial tubules is causally associated with enhanced production of mitochondrial ROS and cardiovascular cell injury in hyperglycaemic conditions.
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MESH Headings
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Apoptosis/drug effects
- Cattle
- Cells, Cultured
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Dynamin I/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Glucose/pharmacology
- Hyperglycemia/metabolism
- Mice
- Mitochondria, Heart/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Rats
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Tianzheng Yu
- Departments of Anesthesiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Mitochondrial Research and Innovation Group, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Shey-Shing Sheu
- Departments of Anesthesiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Mitochondrial Research and Innovation Group, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - James L. Robotham
- Departments of Anesthesiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Mitochondrial Research and Innovation Group, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Yisang Yoon
- Departments of Anesthesiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
- Mitochondrial Research and Innovation Group, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
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37
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Green EM, Barrett CF, Bultynck G, Shamah SM, Dolmetsch RE. The tumor suppressor eIF3e mediates calcium-dependent internalization of the L-type calcium channel CaV1.2. Neuron 2007; 55:615-32. [PMID: 17698014 PMCID: PMC2384234 DOI: 10.1016/j.neuron.2007.07.024] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 04/11/2007] [Accepted: 07/16/2007] [Indexed: 12/20/2022]
Abstract
Voltage-gated calcium channels (VGCCs) convert electrical activity into calcium (Ca2+) signals that regulate cellular excitability, differentiation, and connectivity. The magnitude and kinetics of Ca2+ signals depend on the number of VGCCs at the plasma membrane, but little is known about the regulation of VGCC surface expression. We report that electrical activity causes internalization of the L-type Ca2+ channel (LTC) CaV1.2 and that this is mediated by binding to the tumor suppressor eIF3e/Int6 (eukaryotic initiation factor 3 subunit e). Using total internal reflection microscopy, we identify a population of CaV1.2 containing endosomes whose rapid trafficking is strongly regulated by Ca2+. We define a domain in the II-III loop of CaV1.2 that binds eIF3e and is essential for the activity dependence of both channel internalization and endosomal trafficking. These findings provide a mechanism for activity-dependent internalization and trafficking of CaV1.2 and provide a tantalizing link between Ca2+ homeostasis and a mammalian oncogene.
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Affiliation(s)
- Eric M. Green
- Department of Neurobiology, Stanford University, 299 Campus Drive, Fairchild Research Building D227, Stanford, CA 94305, USA
| | - Curtis F. Barrett
- Department of Molecular and Cellular Physiology, Stanford University, 299 Campus Drive, Fairchild Research Building D227, Stanford, CA 94305, USA
| | - Geert Bultynck
- Department of Biological Sciences, Stanford University, 299 Campus Drive, Fairchild Research Building D227, Stanford, CA 94305, USA
| | - Steven M. Shamah
- Archemix Corporation, 300 Third Street, Cambridge, MA 02142, USA
| | - Ricardo E. Dolmetsch
- Department of Neurobiology, Stanford University, 299 Campus Drive, Fairchild Research Building D227, Stanford, CA 94305, USA
- *Correspondence:
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Chugh J, Sharma S, Hosur RV. Pockets of short-range transient order and restricted topological heterogeneity in the guanidine-denatured state ensemble of GED of dynamin. Biochemistry 2007; 46:11819-32. [PMID: 17910478 DOI: 10.1021/bi701280p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nature and variety in the denatured state of a protein, a non-native state under a given set of conditions, has been a subject of intense debate. Here, using multidimensional NMR, we have characterized the 6 M Gdn-HCl-denatured state of GED, the assembly domain of dynamin. Even under such strongly denaturing conditions, we detected the presence of conformations in slow exchange on the NMR chemical shift time scale. Although the GED oligomer as well as the SDS-denatured monomeric GED were seen to be predominantly helical [Chugh et al. (2006) FEBS J. 273, 388-397], the 6 M Gdn-HCl-denatured GED has largely beta-structural preferences. However, against such a background, we could detect the presence of a population with a short helical stretch (Arg42-Ile47) in the ensemble. The 1H-1H NOEs suggested presence of pockets of transient short-range order along the chain. Put together these segments may lead to a rather small number of interconverting topologically distinguishable ensembles. Spectral density analysis of 15N relaxation rates and {1H}-15N NOE, measured at 600 and 800 MHz, and comparison of J(0) with hydrophobic patches calculated using AABUF approach, indicated presence of four domains of slow motions. These coincided to a large extent with those showing significant Rex. Additionally, a proline residue in the connection between two of these domains seems to cause a fast hinge motion. These observations help enhance our understanding of protein denatured states, and of folding concepts, in general.
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Affiliation(s)
- Jeetender Chugh
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
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39
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Abstract
Mitochondria are derived from eubacteria; however, in most eukaryotes, novel mechanisms for the propagation of this organelle and its genome have evolved. This review focuses on what is currently known about the novel molecular machines that divide and fuse mitochondria.
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Affiliation(s)
- Suzanne Hoppins
- Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
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40
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Kubale V, Abramović Z, Pogacnik A, Heding A, Sentjurc M, Vrecl M. Evidence for a role of caveolin-1 in neurokinin-1 receptor plasma-membrane localization, efficient signaling, and interaction with beta-arrestin 2. Cell Tissue Res 2007; 330:231-45. [PMID: 17713785 DOI: 10.1007/s00441-007-0462-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 07/04/2007] [Indexed: 10/22/2022]
Abstract
This study was focused on the relationship between the plasma-membrane localization of neurokinin-1 receptor (NK1-R) and its endocytic and signaling properties. First, we employed electron paramagnetic resonance (EPR) to study the domain structure of HEK-293 cells and NK1-R microlocalization. EPR spectra and the GHOST condensation routine demonstrated that NK1-R was distributed in a well-ordered domain of HEK-293 cells possibly representing lipid raft/caveolae microdomains, whereas the impairment of caveolae changed the NK1-R plasma-membrane distribution. Internalization and second messenger assays combined with bioluminescence resonance energy transfer were employed subsequently to evaluate the functional importance of the NK1-R microlocalization in lipid raft/caveolae microdomains. The internalization pattern was delineated through the use of dominant-negative mutants (DNM) of caveolin-1 S80E (Cav1 S80E), dynamin-1 K44A (Dyn K44A), and beta-arrestin (beta-arr 319-418) and by means of cell lines that expressed various endogenous levels of beta-arrestins. NK1-R displayed rapid internalization that was substantially reduced by DNMs of dynamin-1 and beta-arrestin and even more profoundly in cells lacking both beta-arrestin1 and beta-arrestin2. These internalization data were highly suggestive of the predominant use of the clathrin-mediated pathway by NK1-R, even though NK1-R tended to reside constitutively in lipid raft/caveolae microdomains. Evidence was also obtained that the proper clustering of the receptor in these microdomains was important for effective agonist-induced NK1-R signaling and for its interaction with beta-arrestin2.
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Affiliation(s)
- Valentina Kubale
- Institute of Anatomy, Histology & Embryology, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, SI-1000, Ljubljana, Slovenia
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Shin N, Lee S, Ahn N, Kim SA, Ahn SG, YongPark Z, Chang S. Sorting nexin 9 interacts with dynamin 1 and N-WASP and coordinates synaptic vesicle endocytosis. J Biol Chem 2007; 282:28939-28950. [PMID: 17681954 DOI: 10.1074/jbc.m700283200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sorting nexin 9 (SNX9) is a member of the sorting nexin family of proteins, each of which contains a characteristic Phox homology domain. SNX9 is widely expressed and plays a role in clathrin-mediated endocytosis, but it is not known if it is present in neuronal cells. We report that SNX9 is expressed in the presynaptic compartment of cultured hippocampal neurons, where it binds to dynamin-1 and N-WASP. Overexpression of full-length SNX9 or a C-terminal truncated version caused severe defects in synaptic vesicle endocytosis during, as well as after, stimulation. Knockdown of SNX9 with short interfering RNA also reduced synaptic vesicle endocytosis, and the W39A mutation of SNX9 abolished the inhibitory effect of SNX9 on endocytosis. Rescue experiments showed that most of the effect of SNX9 on endocytosis results from its interaction with dynamin 1, although its interaction with N-WASP contributes in some degree. We further showed that SNX9 dimerizes through its C-terminal domain, suggesting that it may interact simultaneously with dynamin 1 and N-WASP. We propose that SNX9 interacts with dynamin-1 and N-WASP in presynaptic terminals, where it links actin dynamics and synaptic vesicle endocytosis.
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Affiliation(s)
- Narae Shin
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712
| | - Suho Lee
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712
| | - Namhui Ahn
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712
| | - Soo-A Kim
- Department of Biochemistry, Dongguk University, College of Oriental Medicine, Gyeongju 780-714
| | - Sang-Gun Ahn
- Department of Pathology, Chosun University, College of Dentistry, Gwangju 501-759, South Korea
| | - Zee YongPark
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712
| | - Sunghoe Chang
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712.
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Parker S, Peterkin HS, Baylis HA. Muscular dystrophy associated mutations in caveolin-1 induce neurotransmission and locomotion defects in Caenorhabditis elegans. Invert Neurosci 2007; 7:157-64. [PMID: 17629760 DOI: 10.1007/s10158-007-0051-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 06/11/2007] [Indexed: 12/13/2022]
Abstract
Mutations in human caveolin-3 are known to underlie a range of myopathies. The cav-1 gene of Caenorhabditis elegans is a homologue of human caveolin-3 and is expressed in both neurons and body wall muscles. Within the body wall muscle CAV-1 localises adjacent to neurons, most likely at the neuromuscular junction (NMJ). Using fluorescently tagged CAV-1 and pre- and post-synaptic markers we demonstrate that CAV-1 co-localises with UNC-63, a post-synaptic marker, but not with several pre-synaptic markers. To establish a model for human muscular dystrophies caused by dominant-negative mutations in caveolin-3 we created transgenic animals carrying versions of cav-1 with homologous mutations. These animals had increased sensitivity to levamisole, suggesting a role for cav-1 at the NMJ. Animals carrying a deletion in cav-1 show a similar sensitivity. Sensitivity to levamisole and locomotion were also perturbed in animals carrying a dominant-negative cav-1 and a mutation in dynamin, which is a protein known to interact with caveolins. Thus, indicating an interaction between CAV-1 and dynamin at the NMJ and/or in neurons.
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Affiliation(s)
- Scott Parker
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
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Xi Q, Pauer GJT, Ball SL, Rayborn M, Hollyfield JG, Peachey NS, Crabb JW, Hagstrom SA. Interaction between the photoreceptor-specific tubby-like protein 1 and the neuronal-specific GTPase dynamin-1. Invest Ophthalmol Vis Sci 2007; 48:2837-44. [PMID: 17525220 PMCID: PMC3021943 DOI: 10.1167/iovs.06-0059] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Tubby-like proteins (TULPs) are a family of four proteins, two of which have been linked to neurosensory disease phenotypes. TULP1 is a photoreceptor-specific protein that is mutated in retinitis pigmentosa, an inherited retinal disease characterized by the degeneration of rod and cone photoreceptor cells. To investigate the function of TULP1 in maintaining the health of photoreceptors, the authors sought the identification of interacting proteins. METHODS Immunoprecipitation from retinal lysates, followed by liquid chromatography tandem mass spectrometry and in vitro binding assays, were used to identify TULP1 binding partners. RT-PCR was performed on total RNA from wild-type mouse retina to identify the Dynamin-1 isoform expressed in the retina. Immunocytochemistry was used to determine the localization of TULP1 and Dynamin-1 in photoreceptor cells. Electroretinography (ERG) and light microscopy were used to phenotype tulp1-/- mice at a young age. RESULTS Immunoprecipitation from retinal lysate identified Dynamin-1 as a possible TULP1 binding partner. GST pull-down assays further supported an interaction between TULP1 and Dynamin-1. In photoreceptor cells, Dynamin-1 and TULP1 colocalized primarily to the outer plexiform layer, where photoreceptor terminals synapse on second-order neurons and, to a lesser extent, to the inner segments, where polarized protein translocation occurs. ERG analyses in young tulp1-/- mice indicated a decreased b-wave at ages when the retina retained a full complement of photoreceptor cells. CONCLUSIONS These data indicated that TULP1 interacts with Dynamin-1 and suggested that TULP1 is involved in the vesicular trafficking of photoreceptor proteins, both at the nerve terminal during synaptic transmission and at the inner segment during protein translocation to the outer segment. These results also raised the possibility that normal synaptic function requires TULP1, and they motivate a closer look at synaptic architecture in the developing tulp1-/- retina.
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Affiliation(s)
- Quansheng Xi
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Gayle J. T. Pauer
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Sherry L. Ball
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
- Cleveland Veterans Administration Medical Center, Cleveland, Ohio
| | - Mary Rayborn
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Joe G. Hollyfield
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
- Cleveland Veterans Administration Medical Center, Cleveland, Ohio
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - John W. Crabb
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - Stephanie A. Hagstrom
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
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Tateno H, Li H, Schur MJ, Bovin N, Crocker PR, Wakarchuk WW, Paulson JC. Distinct endocytic mechanisms of CD22 (Siglec-2) and Siglec-F reflect roles in cell signaling and innate immunity. Mol Cell Biol 2007; 27:5699-710. [PMID: 17562860 PMCID: PMC1952126 DOI: 10.1128/mcb.00383-07] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sialic acid-binding immunoglobulin-like lectins (siglecs) are predominately expressed on immune cells. They are best known as regulators of cell signaling mediated by cytoplasmic tyrosine motifs and are increasingly recognized as receptors for pathogens that bear sialic acid-containing glycans. Most siglec proteins undergo endocytosis, an activity tied to their roles in cell signaling and innate immunity. Here, we investigate the endocytic pathways of two siglec proteins, CD22 (Siglec-2), a regulator of B-cell signaling, and mouse eosinophil Siglec-F, a member of the rapidly evolving CD33-related siglec subfamily that are expressed on cells of the innate immune system. CD22 exhibits hallmarks of clathrin-mediated endocytosis and traffics to recycling compartments, consistent with previous reports demonstrating its localization to clathrin domains. Like CD22, Siglec-F mediates endocytosis of anti-Siglec-F and sialoside ligands, a function requiring intact tyrosine-based motifs. In contrast, however, we find that Siglec-F endocytosis is clathrin and dynamin independent, requires ADP ribosylation factor 6, and traffics to lysosomes. The results suggest that these two siglec proteins have evolved distinct endocytic mechanisms consistent with roles in cell signaling and innate immunity.
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Affiliation(s)
- Hiroaki Tateno
- Department of Molecular Biology and Molecular and Experimental Medicine, The Scripps Research Institute, San Diego, CA, USA
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45
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Abstract
The neuron-specific guanosine triphosphatase dynamin 1 has been hypothesized to be critically required for pinching off synaptic vesicles during endocytosis. In a recent publication in Science, Ferguson et al. describe a series of experiments demonstrating an unexpectedly selective requirement of dynamin 1 in synaptic vesicle endocytosis only during high frequency (<10 Hz) stimulation, but not after cessation of the stimulus train.
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Affiliation(s)
- Jurgen Klingauf
- Department of Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany.
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46
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Wu Y, Liang S, Oda Y, Ohmori I, Nishiki TI, Takei K, Matsui H, Tomizawa K. Truncations of amphiphysin I by calpain inhibit vesicle endocytosis during neural hyperexcitation. EMBO J 2007; 26:2981-90. [PMID: 17541403 PMCID: PMC1894779 DOI: 10.1038/sj.emboj.7601741] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 05/08/2007] [Indexed: 11/09/2022] Open
Abstract
Under normal physiological conditions, synaptic vesicle endocytosis is regulated by phosphorylation and Ca(2+)-dependent dephosphorylation of endocytic proteins such as amphiphysin and dynamin. To investigate the regulatory mechanisms that may occur under the conditions of excessive presynaptic Ca(2+) influx observed preceding neural hyperexcitation, we examined hippocampal slices following high-potassium or high-frequency electrical stimulation (HFS). In both cases, three truncated forms of amphiphysin I resulted from cleavage by the protease calpain. In vitro, the binding of truncated amphiphysin I to dynamin I and copolymerization into rings with dynamin I were inhibited, but its interaction with liposomes was not affected. Moreover, overexpression of the truncated form of amphiphysin I inhibited endocytosis of transferrin and synaptic vesicles. Inhibiting calpain prevented HFS-induced depression of presynaptic transmission. Finally, calpain-dependent amphiphysin I cleavage attenuated kainate-induced seizures. These results suggest that calpain-dependent cleavage of amphiphysin I inhibits synaptic vesicle endocytosis during neural hyperexcitation and demonstrate a novel post-translational regulation of endocytosis.
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Affiliation(s)
- Yumei Wu
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shuang Liang
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yoshiya Oda
- Laboratory of Seed Finding Technology, Eisai Co., Ltd, Tsukuba, Japan
| | - Iori Ohmori
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tei-ichi Nishiki
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kohji Takei
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hideki Matsui
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kazuhito Tomizawa
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Shikata-cho 2-5-1, Okayama 700-8558, Japan. Tel.: +81 86 235 7107; Fax: +81 86 235 7111; E-mail:
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Kelly BL, Ferreira A. Beta-amyloid disrupted synaptic vesicle endocytosis in cultured hippocampal neurons. Neuroscience 2007; 147:60-70. [PMID: 17499934 PMCID: PMC1993833 DOI: 10.1016/j.neuroscience.2007.03.047] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 03/02/2007] [Accepted: 03/06/2007] [Indexed: 01/18/2023]
Abstract
Neuronal death leading to gross brain atrophy is commonly seen in Alzheimer's disease (AD) patients. Yet, it is becoming increasingly apparent that the pathogenesis of AD involves early and more discrete synaptic changes in affected brain areas. However, the molecular mechanisms that underlie such synaptic dysfunction remain largely unknown. Recently, we have identified dynamin 1, a protein that plays a critical role in synaptic vesicle endocytosis, and hence, in the signaling properties of the synapse, as a potential molecular determinant of such dysfunction in AD. In the present study, we analyzed beta-amyloid (Abeta)-induced changes in synaptic vesicle recycling in rat cultured hippocampal neurons. Our results showed that Abeta, the main component of senile plaques, caused ultrastructural changes indicative of impaired synaptic vesicle endocytosis in cultured hippocampal neurons that have been stimulated by depolarization with high potassium. In addition, Abeta led to the accumulation of amphiphysin in membrane fractions from stimulated hippocampal neurons. Moreover, experiments using FM1-43 showed reduced dye uptake in stimulated hippocampal neurons treated with Abeta when compared with untreated stimulated controls. Similar results were obtained using a dynamin 1 inhibitory peptide suggesting that dynamin 1 depletion caused deficiency in synaptic vesicle recycling not only in Drosophila but also in mammalian neurons. Collectively, these results showed that Abeta caused a disruption of synaptic vesicle endocytosis in cultured hippocampal neurons. Furthermore, we provided evidence suggesting that Abeta-induced dynamin 1 depletion might play an important role in this process.
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Affiliation(s)
- B L Kelly
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Searle Building Room 5-474, 320 East Superior Street, Chicago, IL 60611, USA
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48
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Abstract
Dynamin I mediates vesicle fission during synaptic vesicle endocytosis (SVE). Its proline-rich domain (PRD) binds the Src-homology 3 (SH3) domain of a subset of proteins that can deform membranes. Syndapin I, amphiphysin I, and endophilin I are its major partners implicated in SVE. Syndapin binding is controlled by phosphorylation at Ser-774 and Ser-778 in the dynamin phospho-box. We now define syndapin and endophilin-binding sites by peptide competition and site-directed mutagenesis. Both bound the same region of the dynamin PRD and both exhibited unusual bidirectional binding modes around core PxxP motifs, unlike amphiphysin which employed a class II binding mode. Endophilin binds to tandem PxxP motifs in the sequence (778)SPTPQRRAPAVPPARPGSR(796) in dynamin, with SPTPQ being an overhang sequence. In contrast, syndapin binding involves two components in the region (772)RRSPTSSPTPQRRAPAVPPARPGSR(796). It required a single PxxP core and a non-PxxP N-terminally anchored extension which bridges the phospho-box and may contribute to binding specificity and affinity. Syndapin binding is exquisitely sensitive to the introduction of negative charges almost anywhere along this region, explaining why it is a highly tuned phospho-sensor. Over-expression of dynamin point mutants that fail to bind syndapin or endophilin inhibit SVE in cultured neurons. Due to overlapping binding sites the interactions between dynamin and syndapin or endophilin were mutually exclusive. Because syndapin acts as a phospho-sensor, this supports its role in depolarization-induced SVE at the synapse, which involves dynamin dephosphorylation. We propose syndapin and endophilin function either at different stages during SVE or in mechanistically distinct types of SVE.
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Affiliation(s)
- Victor Anggono
- Cell Signalling Unit, Children's Medical Research Institute, Wentworthville, New South Wales, Australia
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49
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Abstract
Dynamin I (dynI) is phosphorylated in synaptosomes at Ser(774) and Ser(778) by cyclin-dependent kinase 5 to regulate recruitment of syndapin I for synaptic vesicle endocytosis, and in PC12 cells on Ser(857). Hierarchical phosphorylation of Ser(774) precedes phosphorylation of Ser(778). In contrast, Thr(780) phosphorylation by cdk5 has been reported as the sole site (Tomizawa, K., Sunada, S., Lu, Y. F., Oda, Y., Kinuta, M., Ohshima, T., Saito, T., Wei, F. Y., Matsushita, M., Li, S. T., Tsutsui, K., Hisanaga, S. I., Mikoshiba, K., Takei, K., and Matsui, H. (2003) J. Cell Biol. 163, 813-824). To resolve the discrepancy and to better understand the biological roles of dynI phosphorylation, we undertook a systematic identification of all phosphorylation sites in rat brain nerve terminal dynI. Using phosphoamino acid analysis, exclusively phospho-serine residues were found. Thr(780) phosphorylation was not detectable. Mutation of Ser(774), Ser(778), and Thr(780) confirmed that Thr(780) phosphorylation is restricted to in vitro conditions. Mass spectrometry of (32)P-labeled phosphopeptides separated by two-dimensional mapping revealed seven in vivo phosphorylation sites: Ser(774), Ser(778), Ser(822), Ser(851), Ser(857), Ser(512), and Ser(347). Quantification of (32)P radiation in each phosphopeptide showed that Ser(774) and Ser(778) were the major sites (up to 69% of the total), followed by Ser(851) and Ser(857) (12%), and Ser(853) (2%). Phosphorylation of Ser(851) and Ser(857) was restricted to the long tail splice variant dynIxa and was not hierarchical. Co-purified, (32)P-labeled dynIII was phosphorylated at Ser(759), Ser(763), and Ser(853). Ser(853) is homologous to Ser(851) in dynIxa. The results identify all major and several minor phosphorylation sites in dynI and provide the first measure of their relative abundance and relative responses to depolarization. The multiple phospho-sites suggest subtle regulation of synaptic vesicle endocytosis by new protein kinases and new protein-protein interactions. The homologous dynI and dynIII phosphorylation indicates a high mechanistic similarity. The results suggest a unique role for the long splice variants of dynI and dynIII in nerve terminals.
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Affiliation(s)
- Mark E Graham
- Cell Signaling Unit, Children's Medical Research Institute, Locked Bag 23, Wentworthville, New South Wales 2145, Australia
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Cnops L, Hu TT, Vanden Broeck J, Burnat K, Van Den Bergh G, Arckens L. Age- and experience-dependent expression of Dynamin I and Synaptotagmin I in cat visual system. J Comp Neurol 2007; 504:254-64. [PMID: 17640048 DOI: 10.1002/cne.21415] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dynamin I (Dyn I) and Synaptotagmin I (Syt I) are essential for endocytosis-exocytosis processes, thus for neurotransmission. Despite their related function at presynaptic terminals, Dyn I and Syt I displayed opposite expression patterns during visual cortex maturation in the cat. Dyn I was more abundantly expressed in adults, while Syt I exhibited higher levels in kittens of postnatal day 30 (P30). In area 17 this developmental difference was most obvious in layers II/III. Layer VI displayed a strong hybridization signal for both molecules, independent of age. In addition, Syt I levels were higher in posterior compared to anterior area 17 in adult subjects. Moreover, in higher-order visual areas Syt I was unevenly distributed over the cortical layers, thereby setting clear areal boundaries in mature cortex. In contrast, Dyn I was rather homogeneously distributed over extrastriate areas at both ages. Both molecules thus demonstrated a widespread but different distribution and an opposite temporal expression pattern during visual system development. Notably, monocular deprivation during the critical period of ocular dominance plasticity significantly decreased Syt I expression levels in area 17 ipsilateral to the deprived eye, while no effect was observed on Dyn I expression. We therefore conclude that visual experience induces changes in Syt I expression that may reflect changes in constitutive exocytosis involved in postnatal structural refinements of the visual cortex. On the other hand, the spatial and temporal expression patterns of Dyn I correlate with the establishment and maintenance of the mature neuronal structure rather than neurite remodeling.
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Affiliation(s)
- Lieselotte Cnops
- Laboratory of Neuroplasticity and Neuroproteomics, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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