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Ashouri H, Riyahi Alam N, Khoobi M, Haghgoo S, Rasouli Z, Gholami M. NSF evaluation of gadolinium biodistribution in renally impaired rats: Using novel metabolic Gd2O3 nanoparticles coated with β-cyclodextrin (Gd2O3@PCD) in MR molecular imaging. Magn Reson Imaging 2024; 107:120-129. [PMID: 38215955 DOI: 10.1016/j.mri.2024.01.003] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 12/31/2023] [Accepted: 01/08/2024] [Indexed: 01/14/2024]
Abstract
The use of conventional gadolinium(Gd)-based contrast agents in magnetic resonance imaging (MRI) poses a significant risk of Nephrogenic Systemic Fibrosis (NSF) syndrome in patients with impaired renal function (grades 4 and 5). To address this issue, a new study has introduced a novel metabolic Gadolinium oxide nanoparticle (Gd2O3 NPs) coated with β-cyclodextrin (βCD). The study aims to investigate NSF syndrome by quantifying tissue Gd deposition biodistribution in renal impairment rats using MR molecular imaging. This is the first study of its kind to use this approach. A group of 20 rats were divided into four groups, each containing five rats that underwent 5/6 nephrectomy. The rats received 12 intravenous injections of a novel homemade synthesized gadolinium oxide polycyclodextrin (Gd2O3@PCD) at a dose of 0.1 mmol/kg, conventional contrast agents (CAs) drugs of Omniscan (Gd-DTPA-BMA) and Dotarem (Gd-DOTA), at a dose of 2.5 mmol/kg, and 250 μl saline for two injections per week during six weeks. T1-weighted MR imaging was performed before the injections and once a week for six weeks to quantify Gd deposition in four different organs (skin, liver, heart, and lung) in rats using inductively coupled plasma mass spectrometry (ICP-MS). The relationship between Signal-to-Noise Ratio (SNR) and biodistribution of Gd deposition due to NSF-induced syndrome was also calculated. The results of the study showed that the Gd concentrations in tissues were significantly higher in the Gd2O3@PCD group compared to the other groups, without any significant histopathological changes (P < 0.05). In the Gd2O3@PCD group, Gd was mainly deposited in the skin, followed by the liver, lung, and heart, without any symptoms of thickening or hardening of the skin. The Gd concentrations in the skin, liver, lung, and heart were significantly lower in the Dotarem group than in the Omniscan group (P < 0.05). In the histopathological examinations, the Omniscan group showed increased cellularity in the dermis. A significant hyperintensity was observed in the Gd2O3@PCD-treated rats compared to the Dotarem and Omniscan groups in the liver, heart, and lung. Compared to conventional Gd-based CAs, the novel metabolically Gd2O3@PCD with increased SNR, biosafety, and a considerably lower probability of developing NSF, has potential applicability for diagnosing patients with renal diseases in clinical MR Molecular Imaging (MRMI).
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Affiliation(s)
- Hanieh Ashouri
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences(TUMS), Tehran, Iran
| | - Nader Riyahi Alam
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences(TUMS), Tehran, Iran; Concordia University, Perform Center, Montreal, Quebec, Canada; Biomaterials Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.
| | - Mehdi Khoobi
- Biomaterials Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran; Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Soheila Haghgoo
- Pharmaceutical Department, Food & Drug Laboratory Research Center, Ministry of Health, Tehran, Iran
| | - Zahra Rasouli
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences(TUMS), Tehran, Iran; Medical Imaging Center, Motahari Hospital, Jahrom University of Medical Sciences (JUMS), Jahrom, Iran
| | - Mahdi Gholami
- Department of Toxicology and Pharmacology, Toxicology and Poisoning Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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Liu F, He R, Xu X, Zhu M, Yu H, Liu Y. Munc18c accelerates SNARE-dependent membrane fusion in the presence of regulatory proteins α-SNAP and NSF. J Biol Chem 2024; 300:105782. [PMID: 38395304 PMCID: PMC10959665 DOI: 10.1016/j.jbc.2024.105782] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/23/2024] [Accepted: 02/18/2024] [Indexed: 02/25/2024] Open
Abstract
Intracellular vesicle fusion is driven by the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and their cofactors, including Sec1/Munc18 (SM), α-SNAP, and NSF. α-SNAP and NSF play multiple layers of regulatory roles in the SNARE assembly, disassembling the cis-SNARE complex and the prefusion SNARE complex. How SM proteins coupled with NSF and α-SNAP regulate SNARE-dependent membrane fusion remains incompletely understood. Munc18c, an SM protein involved in the exocytosis of the glucose transporter GLUT4, binds and activates target (t-) SNAREs to accelerate the fusion reaction through a SNARE-like peptide (SLP). Here, using an in vitro reconstituted system, we discovered that α-SNAP blocks the GLUT4 SNAREs-mediated membrane fusion. Munc18c interacts with t-SNAREs to displace α-SNAP, which overcomes the fusion inhibition. Furthermore, Munc18c shields the trans-SNARE complex from NSF/α-SNAP-mediated disassembly and accelerates SNARE-dependent fusion kinetics in the presence of NSF and α-SNAP. The SLP in domain 3a is indispensable in Munc18c-assisted resistance to NSF and α-SNAP. Together, our findings demonstrate that Munc18c protects the prefusion SNARE complex from α-SNAP and NSF, promoting SNARE-dependent membrane fusion through its SLP.
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Affiliation(s)
- Furong Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xinyu Xu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Min Zhu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
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Iyad N, S.Ahmad M, Alkhatib SG, Hjouj M. Gadolinium contrast agents- challenges and opportunities of a multidisciplinary approach: Literature review. Eur J Radiol Open 2023; 11:100503. [PMID: 37456927 PMCID: PMC10344828 DOI: 10.1016/j.ejro.2023.100503] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/09/2023] [Accepted: 06/23/2023] [Indexed: 07/18/2023] Open
Abstract
Contrast agents is used in magnetic resonance imaging (MRI) to improve the visibility of the details of the organ structures. Gadolinium-based contrast agent (GBCA) has been used since 1988 in MRI for diagnostic and follow-up of patients, the gadolinium good properties make it an effective choice for enhance the signal in MRI by increase its intensity and shortening the relaxation time of the proton. Recently, many studies show a gadolinium deposition in different human organs due to release of free gadolinium various body organs or tissue, which led to increased concern about the use of gadolinium agents, in this study, the potential diseases that may affect the patient and side effects that appear on the patient and related to accumulation of gadolinium were clarified, the study focused on the organs such as brain and bones in which gadolinium deposition was found and the lesions associated with it, and the diseases associated with gadolinium retention includes Nephrogenic Systemic Fibrosis (NSF) and Gadolinium deposition disease (GDD). Some studies tended to improve the contrast agents by developing a new non-gadolinium agents or development of next-generation gadolinium agents. In this review article the latest knowledge about MRI contrast agent.
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Affiliation(s)
- Nebal Iyad
- Ibn Rushd Radiology Centre, Hebron, Palestine
| | - Muntaser S.Ahmad
- Ibn Rushd Radiology Centre, Hebron, Palestine
- Department of Medical Imaging, Faculty of Allied Medical Health, Palestine Ahliya University, Dheisha, Bethlehem, Palestine
| | - Sanaa G. Alkhatib
- Department of Medical Imaging, Faculty of Allied Medical Health, Palestine Ahliya University, Dheisha, Bethlehem, Palestine
| | - Mohammad Hjouj
- Medical Imaging Department, Faculty of Health Professions, Al-Quds University, Abu Deis - Main Campus, Jerusalem, Palestine
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Gao Y, Khan YA, Mo W, White KI, Perkins M, Pfuetzner RA, Trapani JG, Brunger AT, Nicolson T. Sensory deficit screen identifies nsf mutation that differentially affects SNARE recycling and quality control. Cell Rep 2023; 42:112345. [PMID: 37027300 PMCID: PMC10524599 DOI: 10.1016/j.celrep.2023.112345] [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: 11/15/2022] [Revised: 02/24/2023] [Accepted: 03/21/2023] [Indexed: 04/08/2023] Open
Abstract
The AAA+ NSF complex is responsible for SNARE complex disassembly both before and after membrane fusion. Loss of NSF function results in pronounced developmental and degenerative defects. In a genetic screen for sensory deficits in zebrafish, we identified a mutation in nsf, I209N, that impairs hearing and balance in a dosage-dependent manner without accompanying defects in motility, myelination, and innervation. In vitro experiments demonstrate that while the I209N NSF protein recognizes SNARE complexes, the effects on disassembly are dependent upon the type of SNARE complex and I209N concentration. Higher levels of I209N protein produce a modest decrease in binary (syntaxin-SNAP-25) SNARE complex disassembly and residual ternary (syntaxin-1A-SNAP-25-synaptobrevin-2) disassembly, whereas at lower concentrations binary disassembly activity is strongly reduced and ternary disassembly activity is absent. Our study suggests that the differential effect on disassembly of SNARE complexes leads to selective effects on NSF-mediated membrane trafficking and auditory/vestibular function.
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Affiliation(s)
- Yan Gao
- Department of Otolaryngology, Head and Neck Surgery, Stanford Medical School, 300 Pasteur Drive, Stanford, CA 94303, USA
| | - Yousuf A Khan
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Center for Biomedical Informatics Research, Stanford University, Stanford, CA, USA
| | - Weike Mo
- Graduate Program Biomedical Sciences, Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - K Ian White
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Matthew Perkins
- Department of Biology and Neuroscience Program, Amherst College, Amherst, MA 01002, USA
| | - Richard A Pfuetzner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Josef G Trapani
- Department of Biology and Neuroscience Program, Amherst College, Amherst, MA 01002, USA
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Teresa Nicolson
- Department of Otolaryngology, Head and Neck Surgery, Stanford Medical School, 300 Pasteur Drive, Stanford, CA 94303, USA.
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Abstract
Neurotransmitters are stored in small membrane-bound vesicles at synapses; a subset of synaptic vesicles is docked at release sites. Fusion of docked vesicles with the plasma membrane releases neurotransmitters. Membrane fusion at synapses, as well as all trafficking steps of the secretory pathway, is mediated by SNARE proteins. The SNAREs are the minimal fusion machinery. They zipper from N-termini to membrane-anchored C-termini to form a 4-helix bundle that forces the apposed membranes to fuse. At synapses, the SNAREs comprise a single helix from syntaxin and synaptobrevin; SNAP-25 contributes the other two helices to complete the bundle. Unc13 mediates synaptic vesicle docking and converts syntaxin into the permissive "open" configuration. The SM protein, Unc18, is required to initiate and proofread SNARE assembly. The SNAREs are then held in a half-zippered state by synaptotagmin and complexin. Calcium removes the synaptotagmin and complexin block, and the SNAREs drive vesicle fusion. After fusion, NSF and alpha-SNAP unwind the SNAREs and thereby recharge the system for further rounds of fusion. In this chapter, we will describe the discovery of the SNAREs, their relevant structural features, models for their function, and the central role of Unc18. In addition, we will touch upon the regulation of SNARE complex formation by Unc13, complexin, and synaptotagmin.
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Affiliation(s)
- Mark T Palfreyman
- School of Biological Sciences, and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Sam E West
- School of Biological Sciences, and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Erik M Jorgensen
- School of Biological Sciences, and Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA.
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Abstract
Major recent advances and previous data have led to a plausible model of how key proteins mediate neurotransmitter release. In this model, the soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) proteins syntaxin-1, SNAP-25, and synaptobrevin form tight complexes that bring the membranes together and are crucial for membrane fusion. NSF and SNAPs disassemble SNARE complexes and ensure that fusion occurs through an exquisitely regulated pathway that starts with Munc18-1 bound to a closed conformation of syntaxin-1. Munc18-1 also binds to synaptobrevin, forming a template to assemble the SNARE complex when Munc13-1 opens syntaxin-1 while bridging the vesicle and plasma membranes. Synaptotagmin-1 and complexin bind to partially assembled SNARE complexes, likely stabilizing them and preventing fusion until Ca2+ binding to synaptotagmin-1 causes dissociation from the SNARE complex and induces interactions with phospholipids that help trigger release. Although fundamental questions remain about the mechanism of membrane fusion, these advances provide a framework to investigate the mechanisms underlying presynaptic plasticity.
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Affiliation(s)
- Josep Rizo
- Departments of Biophysics, Biochemistry, and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA;
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Zhang H, Sun Y, Yau SY, Zhou Y, Song X, Zhang HT, Zhu B, Wu H, Chen G. Synergistic effects of two natural compounds of iridoids on rapid antidepressant action by up-regulating hippocampal PACAP signaling. Br J Pharmacol 2022; 179:4078-4091. [PMID: 35362097 DOI: 10.1111/bph.15847] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/30/2022] [Accepted: 02/28/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Current mainstream antidepressants have limited efficacy and a delayed onset of action. Yueju is a traditional herbal medicine conferring rapid antidepressant activity. Here we attempted to identify the effective compounds from Yueju and the underlying mechanisms. EXPERIMENTAL APPROACH A transcriptomic analysis was employed to discover key candidate molecules for rapid antidepressant response. The enriched compounds in Yueju were identified with HPLC. Antidepressant effects were evaluated periodically using various behavioral paradigms. The mechanistic signaling was assessed using site-directed pharmacological intervention or optogenetic manipulation. KEY RESULTS A transcriptomic analysis revealed that Yueju up-regulated pituitary adenylate cyclase activating polypeptide (PACAP) expression in the hippocampus. Two iridoids geniposide (GP) and shanzhiside methyl-ester (SM) were enriched in Yueju. Co-treatment of GP and SM each at an equivalent dose in Yueju synergistically increased PACAP expression and elicited rapid antidepressant effects, which were prevented by intra-hippocampal dentate gyrus (DG) infusions of a PACAP antagonist or optogenetic inactivation of PACAP-expressing neurons. GP-SM co-treatment rapidly reduced CaMKII phosphorylation and enhanced mTOR/4EBP1/P70S6k/BDNF signaling, while intra-DG infusions of a CaMKII activator blunted rapid antidepressant effects and BDNF expression up-regulation induced by GP-SM co-treatment. A single administration of GP-SM rapidly improved depression-like behaviors and up-regulated hippocampal PACAP signaling in the repeated corticosterone-induced depression model, further confirming its rapid antidepressant action and the involvement of PACAP. CONCLUSION AND IMPLICATIONS GP-SM co-treatment elicited a synergistic effect on rapid antidepressant effects via triggering hippocampal PACAP activity and associated CaMKII-BDNF signaling, shedding lights on the development of novel targeted antidepressants.
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Affiliation(s)
- Hailou Zhang
- Interdisciplinary Institute for Personalized Medicine in Brain Disorders & School of Chinese Medicine, Jinan University, Guangzhou, China.,College of Traditional Chinese Medicine & College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China.,Co-innovation Center of Neurogeneration, Nantong University, Nantong, Jiangsu, China
| | - Yan Sun
- Interdisciplinary Institute for Personalized Medicine in Brain Disorders & School of Chinese Medicine, Jinan University, Guangzhou, China.,College of Traditional Chinese Medicine & College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Suk-Yu Yau
- Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong, China
| | - Yanmeng Zhou
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, China
| | - Xinxin Song
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, China
| | - Han-Ting Zhang
- Departments of Neuroscience and Behavioral Medicine & Psychiatry, the Rockefeller Neuroscience Institute, West Virginia University Health Sciences Center, Morgantown, WV, USA
| | - Boran Zhu
- College of Traditional Chinese Medicine & College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Haoxin Wu
- College of Traditional Chinese Medicine & College of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Gang Chen
- Interdisciplinary Institute for Personalized Medicine in Brain Disorders & School of Chinese Medicine, Jinan University, Guangzhou, China.,Departments of Psychiatry & Clinical and Translational Institute of Psychiatric Disorders, First Affiliated Hospital of Jinan University, Guangzhou, China.,Co-innovation Center of Neurogeneration, Nantong University, Nantong, Jiangsu, China
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Abraham A, Mathew J, Thomas S. Resources for Starting a Company. Methods Mol Biol 2022; 2412:529-542. [PMID: 34918267 DOI: 10.1007/978-1-0716-1892-9_30] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
After having painstakingly invented a new product, filed patents, published papers in peer-reviewed journals, you reach out to companies to license your product. More often, they reject the product as it is novel and risky. The next option is to sell the product through a startup company setup by yourself. Most inventors think that it is difficult to set up a company, find finance to run the company, and manage it. Fortunately, there are several government entities and private investment firms that can help you with setting up a company. This chapter provides information on resources for setting up and running a company.
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Affiliation(s)
- Ann Abraham
- Lankenau Institute for Medical Research, Wynnewood, USA
| | - Jude Mathew
- Lebow College of Business, Drexel University, Philadelphia, PA, USA
| | - Sunil Thomas
- Lankenau Institute for Medical Research, Wynnewood, USA.
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Huang P, Zhao C, Chen C, Whiteheart SW, Liu-Chen LY. Does GEC1 Enhance Expression and Forward Trafficking of the Kappa Opioid Receptor (KOR) via Its Ability to Interact with NSF Directly? Handb Exp Pharmacol 2022; 271:83-96. [PMID: 33404775 DOI: 10.1007/164_2020_398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We reported previously that GEC1 (glandular epithelial cell 1), a member of microtubule-associated proteins (MAPs), interacted directly with the C-tail of KOR (KCT) and tubulin and enhanced cell surface expression of KOR in CHO cells by facilitating its trafficking along the export pathway. Two GEC1 analogs (GABARAP and GATE16) were also shown to increase KOR expression. In addition, to understand the underlying mechanism, we demonstrated that N-ethylmaleimide-sensitive factor (NSF), an essential component for membrane fusion, co-immunoprecipitated with GEC1 from brain extracts. In this study, using pull-down techniques, we have found that (1) GEC1 interacts with NSF directly and prefers the ADP-bound NSF to the ATP-bound NSF; (2) D1 and/or D2 domain(s) of NSF interact with GEC1, but the N domain of NSF does not; (3) NSF does not interact with KCT directly, but forms a protein complex with KCT via GEC1; (4) NSF and/or α-SNAP do not affect KCT-GEC1 interaction. Thus, GEC1 (vs the α-SNAP/SNAREs complex) binds to NSF in distinctive ways in terms of the ADP- or ATP-bound form and domains of NSF involved. In conclusion, GEC1 may, via its direct interactions with KOR, NSF, and tubulin, enhance trafficking and fusion of KOR-containing vesicles selectively along the export pathway, which leads to increase in surface expression of KOR. GABARAP and GATE16 may enhance KOR expression in a similar way.
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Ramírez J, Morales M, Osinalde N, Martínez-Padrón I, Mayor U, Ferrús A. The ubiquitin ligase Ariadne-1 regulates neurotransmitter release via ubiquitination of NSF. J Biol Chem 2021; 296:100408. [PMID: 33581113 DOI: 10.1016/j.jbc.2021.100408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/17/2022] Open
Abstract
Ariadne-1 (Ari-1) is an E3 ubiquitin-ligase essential for neuronal development, but whose neuronal substrates are yet to be identified. To search for putative Ari-1 substrates, we used an in vivo ubiquitin biotinylation strategy coupled to quantitative proteomics of Drosophila heads. We identified 16 candidates that met the established criteria: a significant change of at least twofold increase on ubiquitination, with at least two unique peptides identified. Among those candidates, we identified Comatose (Comt), the homologue of the N-ethylmaleimide sensitive factor (NSF), which is involved in neurotransmitter release. Using a pull-down approach that relies on the overexpression and stringent isolation of a GFP-fused construct, we validate Comt/NSF to be an ubiquitination substrate of Ari-1 in fly neurons, resulting in the preferential monoubiquitination of Comt/NSF. We tested the possible functional relevance of this modification using Ari-1 loss-of-function mutants, which displayed a lower rate of spontaneous neurotransmitter release due to failures at the presynaptic side. By contrast, evoked release in Ari-1 mutants was enhanced compared with controls in a Ca2+-dependent manner without modifications in the number of active zones, indicating that the probability of release per synapse is increased in these mutants. This phenotype distinction between spontaneous and evoked release suggests that NSF activity may discriminate between these two types of vesicle fusion. Our results thus provide a mechanism to regulate NSF activity in the synapse through Ari-1-dependent ubiquitination.
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11
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Kalantari K, Swaminathan S. Use of Gadolinium in Individuals with Reduced Kidney Function. Clin J Am Soc Nephrol 2021; 16:304-306. [PMID: 33431379 PMCID: PMC7863651 DOI: 10.2215/cjn.13950820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kambiz Kalantari
- Division of Nephrology, University of Virginia Health System, Charlottesville, Virginia
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12
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Umanah GKE, Ghasemi M, Yin X, Chang M, Kim JW, Zhang J, Ma E, Scarffe LA, Lee YI, Chen R, Tangella K, McNamara A, Abalde-Atristain L, Dar MA, Bennett S, Cortes M, Andrabi SA, Doulias PT, Ischiropoulos H, Dawson TM, Dawson VL. AMPA Receptor Surface Expression Is Regulated by S-Nitrosylation of Thorase and Transnitrosylation of NSF. Cell Rep 2020; 33:108329. [PMID: 33147468 PMCID: PMC7737632 DOI: 10.1016/j.celrep.2020.108329] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 12/13/2019] [Revised: 08/05/2020] [Accepted: 10/08/2020] [Indexed: 01/13/2023] Open
Abstract
The regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) trafficking affects multiple brain functions, such as learning and memory. We have previously shown that Thorase plays an important role in the internalization of AMPARs from the synaptic membrane. Here, we show that N-methyl-d-aspartate receptor (NMDAR) activation leads to increased S-nitrosylation of Thorase and N-ethylmaleimide-sensitive factor (NSF). S-nitrosylation of Thorase stabilizes Thorase-AMPAR complexes and enhances the internalization of AMPAR and interaction with protein-interacting C kinase 1 (PICK1). S-nitrosylated NSF is dependent on the S-nitrosylation of Thorase via trans-nitrosylation, which modulates the surface insertion of AMPARs. In the presence of the S-nitrosylation-deficient C137L Thorase mutant, AMPAR trafficking, long-term potentiation, and long-term depression are impaired. Overall, our data suggest that both S-nitrosylation and interactions of Thorase and NSF/PICK1 are required to modulate AMPAR-mediated synaptic plasticity. This study provides critical information that elucidates the mechanism underlying Thorase and NSF-mediated trafficking of AMPAR complexes.
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Affiliation(s)
- George K E Umanah
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts School of Medicine, Worcester, MA 01655, USA
| | - Xiling Yin
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Melissa Chang
- University of California, Irvine, School of Medicine, Irvine, CA 92697-3950, USA
| | - Jin Wan Kim
- University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jianmin Zhang
- Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Beijing 100005, China
| | - Erica Ma
- Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, MD 21205, USA
| | - Leslie A Scarffe
- Division of Neurology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Yun-Il Lee
- Division of Biotechnology, Well Aging Research Center, DGIST, Daegu, Republic of Korea
| | - Rong Chen
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kavya Tangella
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amy McNamara
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Mohamad A Dar
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Samuel Bennett
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Marisol Cortes
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shaida A Andrabi
- Department of Pharmacology and Toxicology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Paschalis-Thomas Doulias
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Harry Ischiropoulos
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute, The University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pharmacology, The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ted M Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, University of Massachusetts School of Medicine, Worcester, MA 01655, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Valina L Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, University of Massachusetts School of Medicine, Worcester, MA 01655, USA; Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Abstract
All major United States institutional advocates for research on the biology of aging and for the leading causes of death assert that aging is the greatest risk factor for these deaths. Nevertheless, all fail to support research on the etiology of aging despite having mechanisms to do so. Aging is a problem in physics and not biology. It is a multibillion dollar miss-understanding to believe that the resolution of any or all age associated diseases will reveal information on the underlying aging process. The goal in research on the etiology of aging is to use the new revolutionary methods to study single molecules and their constituent atoms to uncover the qualitative and quantitative status of molecules in old cells that differ from that in young cells. These differences are the conditions that can explain why a common cause may exist for the risk factor for all age-associated diseases. The tyranny of the phrase "research on aging" could apply to almost any human institution. In the absence of a strict definition when used it has become a costly error in gerontology communication. Research on the biology of aging has become its greatest victim. Because aging is a universal manifestation of the fate of all matter, it is the provenance of the National Science Foundation because its stated purpose excludes research in the medical sciences.
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14
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Soto-Beasley AI, Walton RL, Valentino RR, Hook PW, Labbé C, Heckman MG, Johnson PW, Goff LA, Uitti RJ, McLean PJ, Springer W, McCallion AS, Wszolek ZK, Ross OA. Screening non-MAPT genes of the Chr17q21 H1 haplotype in Parkinson's disease. Parkinsonism Relat Disord 2020; 78:138-144. [PMID: 32829096 PMCID: PMC7686230 DOI: 10.1016/j.parkreldis.2020.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 07/04/2020] [Accepted: 07/24/2020] [Indexed: 01/07/2023]
Abstract
INTRODUCTION The microtubule-associated protein tau (MAPT) gene is considered a strong genetic risk factor for Parkinson's disease (PD) in Caucasians. MAPT is located within an inversion region of high linkage disequilibrium designated as H1 and H2 haplotype, and contains eight other genes which have been implicated in neurodegeneration. The aim of the current study was to identify common coding variants in strong linkage disequilibrium (LD) within the associated loci on chr17q21 harboring MAPT. METHODS Sanger sequencing of coding exons in 90 Caucasian late-onset PD (LOPD) patients was performed. Specific gene sequencing for LRRC37A, LRRC37A2, ARL17A and ARL17B was not possible given the high homology, presence of pseudogenes and copy number variants that are in the region, and therefore four genes (NSF, KANSL1, SPPL2C, and CRHR1) were included in the analysis. Coding variants from these four genes that did not perfectly tag (r2 = 1) the MAPT H1/H2 haplotype were genotyped in an independent replication series of Caucasian PD cases (N = 851) and controls (N = 730). RESULTS In the 90 LOPD cases we identified 30 coding variants. Eleven non-synonymous variants tagged the MAPT H1/H2 haplotype, including two SPPL2C variants (rs12185233 and rs12373123) that had high pathogenic combined annotation dependent depletion (CADD) scores of >20. In the replication series, the non-synonymous KANSL1 rs17585974 variant was in very strong LD with MAPT H1/H2 and had a high CADD score of 24.7. CONCLUSION We have identified several non-synonymous variants across neighboring genes of MAPT that may warrant further genetic and functional investigation within the biological etiology of PD.
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Affiliation(s)
| | - Ronald L. Walton
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Paul W. Hook
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Catherine Labbé
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Michael G. Heckman
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Patrick W. Johnson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Loyal A. Goff
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,Solomon H. Snyder Department of Neuroscience and Kavli Neurodiscovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ryan J. Uitti
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Pamela J. McLean
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA,Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences
| | - Wolfdieter Springer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA,Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences
| | - Andrew S. McCallion
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | | | - Owen A. Ross
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA,Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL 32224, USA,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland,Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences,Corresponding author’s contact information: Owen A. Ross, Ph.D., Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, Tel: +1 (904)-953-6280, Fax: +1 (904)-953-7370,
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15
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Wang H, Zhang C, Xiao H. Mechanism of membrane fusion: protein-protein interaction and beyond. Int J Physiol Pathophysiol Pharmacol 2019; 11:250-257. [PMID: 31993099 PMCID: PMC6971501] [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] [Grants] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 11/20/2019] [Indexed: 06/10/2023]
Abstract
Membrane fusion is a universal event in all living organism. It is at the heart of intracellular organelle biogenesis and membrane traffic processes such as endocytosis and exocytosis, and is also used by enveloped viruses to enter hosting cells. Regarding the cellular mechanisms underlying membrane fusion, pioneering studies by Randy Schekman, James Rothman, Thomas C. Südhof and their colleagues have demonstrated the function of specific proteins and protein-protein interactions as essential fusogenic factor to initiate membrane fusion. Since then, function of lipids and protein-lipid interaction has also been identified as important players in membrane fusion. Based on that NSF (NEM-sensitive factor where NEM stands for N-ethyl-maleimide) and acyl-CoA are required for the membrane fusion of transporting vesicles with Golgi cisternae, it is further suggested that the transfer of the acyl chain to a molecule(s) is essential for membrane fusion. Among the previously identified fusogens, phosphatidic acid (PA) is found as an acyl chain recipient. Functionally, acylation of PA is required for tethering the membranes of Rab5a vesicles and early endosomes together during membrane fusion. As certain threshold of proximity between the donor and acceptor membrane is required to initiate membrane fusion, fusogenic factors beyond protein-protein and protein-lipid interaction need to be identified.
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Affiliation(s)
- Hongbing Wang
- Department of Physiology, Michigan State UniversityEast Lansing, Michigan 48824, USA
- Neuroscience Program, Michigan State UniversityEast Lansing, Michigan 48824, USA
| | - Chengliang Zhang
- Department of Physiology, Michigan State UniversityEast Lansing, Michigan 48824, USA
| | - Hua Xiao
- Department of Physiology, Michigan State UniversityEast Lansing, Michigan 48824, USA
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16
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Jun Y, Wickner W. Sec17 (α-SNAP) and Sec18 ( NSF) restrict membrane fusion to R-SNAREs, Q-SNAREs, and SM proteins from identical compartments. Proc Natl Acad Sci U S A 2019; 116:23573-81. [PMID: 31685636 DOI: 10.1073/pnas.1913985116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Membrane fusion at each organelle requires conserved proteins: Rab-GTPases, effector tethering complexes, Sec1/Munc18 (SM)-family SNARE chaperones, SNAREs of the R, Qa, Qb, and Qc families, and the Sec17/α-SNAP and ATP-dependent Sec18/NSF SNARE chaperone system. The basis of organelle-specific fusion, which is essential for accurate protein compartmentation, has been elusive. Rab family GTPases, SM proteins, and R- and Q-SNAREs may contribute to this specificity. We now report that the fusion supported by SNAREs alone is both inefficient and promiscuous with respect to organelle identity and to stimulation by SM family proteins or complexes. SNARE-only fusion is abolished by the disassembly chaperones Sec17 and Sec18. Efficient fusion in the presence of Sec17 and Sec18 requires a tripartite match between the organellar identities of the R-SNARE, the Q-SNAREs, and the SM protein or complex. The functions of Sec17 and Sec18 are not simply negative regulation; they stimulate fusion with either vacuolar SNAREs and their SM protein complex HOPS or endoplasmic reticulum/cis-Golgi SNAREs and their SM protein Sly1. The fusion complex of each organelle is assembled from its own functionally matching pieces to engage Sec17/Sec18 for fusion stimulation rather than inhibition.
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17
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Abstract
Background To date, few data on the safety profile of gadoterate meglumine in pediatric patients are available. Purpose To assess the safety profile of gadoterate meglumine in routine practice, to detect any case of nephrogenic systemic fibrosis (NSF) suspicion and to collect efficacy data. Material and Methods The pediatric population of the observational SECURE study comprised 1631 patients scheduled for contrast-enhanced magnetic resonance imaging (MRI) with gadoterate meglumine (dose: 0.1 mmol/kg). Risk factors, MRI types and immediate adverse events (AEs) were systematically recorded. Patients with moderate to severe renal impairment were followed up for at least 3 months for detection of any NSF suspicion. Efficacy was assessed by the on-site radiologist in terms of image quality and ability to come to diagnosis. Results The population included 106 children (6.5%) aged <2 years, 815 (50.0%) aged 2 to <12 years and 710 (43.5%) aged 12 to <18 years, with a mean (± SD) age of 10.2 (± 4.9) years. Central nervous system exploration was the most frequent MRI type (80.4%) and main risk factors were any stage of renal insufficiency (9.8%) and allergies (5.2%). Only one AE (vomiting) that was deemed doubtfully related to gadoterate meglumine was observed. No suspicions of NSF were reported. Good to very good image quality was obtained for 98.4% of pediatric patients and diagnosis was established in 99.6% of cases. Conclusion This study confirmed the good safety profile of gadoterate meglumine in routine practice in a large pediatric population. The study is registered on https://clinicaltrials.gov/ with the identifier NCT01523873.
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Affiliation(s)
- De-Hua Chang
- Department of Radiology, University Clinic of Cologne, Cologne, Germany
| | - Jean-Pierre Pracros
- Department of Pediatric Radiology, Women-Mother and Child Hospital, Hospices Civils de Lyon, Lyon, France
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18
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Holowka S, Shroff M, Chavhan GB. Use and Safety of Gadolinium Based Contrast Agents in Pediatric MR Imaging. Indian J Pediatr 2019; 86:961-6. [PMID: 30796704 DOI: 10.1007/s12098-019-02891-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/28/2019] [Indexed: 01/23/2023]
Abstract
Gadolinium-based contrast agents (GBCA) used for MR imaging are a valuable imaging resource that has benefited patient management over last three decades and largely have a high safety profile. However, recently, adverse effects related to GBCA like nephrogenic systemic fibrosis (NSF) and asymptomatic gadolinium deposition in tissues including brain are concerning. While NSF has largely stopped occurring due to precautions and guidelines to not use GBCA in patients with poor renal function, the long term effects of gadolinium deposition, especially in brain, are not known at this stage. Cautious approach needs to be taken with risk-benefit analysis in each patient to avoid its administration when not necessary. In this review, authors discuss basics of gadolinium, mechanism of enhancement, agents in clinical use and safety issues, and in the end, offer some solutions for safety concerns.
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19
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Sparks RP, Arango AS, Starr ML, Aboff ZL, Hurst LR, Rivera-Kohr DA, Zhang C, Harnden KA, Jenkins JL, Guida WC, Tajkhorshid E, Fratti RA. A small-molecule competitive inhibitor of phosphatidic acid binding by the AAA+ protein NSF/Sec18 blocks the SNARE-priming stage of vacuole fusion. J Biol Chem 2019; 294:17168-17185. [PMID: 31515268 DOI: 10.1074/jbc.ra119.008865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 09/04/2019] [Indexed: 12/13/2022] Open
Abstract
The homeostasis of most organelles requires membrane fusion mediated by soluble N -ethylmaleimide-sensitive factor (NSF) attachment protein receptors (SNAREs). SNAREs undergo cycles of activation and deactivation as membranes move through the fusion cycle. At the top of the cycle, inactive cis-SNARE complexes on a single membrane are activated, or primed, by the hexameric ATPase associated with the diverse cellular activities (AAA+) protein, N-ethylmaleimide-sensitive factor (NSF/Sec18), and its co-chaperone α-SNAP/Sec17. Sec18-mediated ATP hydrolysis drives the mechanical disassembly of SNAREs into individual coils, permitting a new cycle of fusion. Previously, we found that Sec18 monomers are sequestered away from SNAREs by binding phosphatidic acid (PA). Sec18 is released from the membrane when PA is hydrolyzed to diacylglycerol by the PA phosphatase Pah1. Although PA can inhibit SNARE priming, it binds other proteins and thus cannot be used as a specific tool to further probe Sec18 activity. Here, we report the discovery of a small-molecule compound, we call IPA (inhibitor of priming activity), that binds Sec18 with high affinity and blocks SNARE activation. We observed that IPA blocks SNARE priming and competes for PA binding to Sec18. Molecular dynamics simulations revealed that IPA induces a more rigid NSF/Sec18 conformation, which potentially disables the flexibility required for Sec18 to bind to PA or to activate SNAREs. We also show that IPA more potently and specifically inhibits NSF/Sec18 activity than does N-ethylmaleimide, requiring the administration of only low micromolar concentrations of IPA, demonstrating that this compound could help to further elucidate SNARE-priming dynamics.
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Affiliation(s)
- Robert P Sparks
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Andres S Arango
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Matthew L Starr
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Zachary L Aboff
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Logan R Hurst
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - David A Rivera-Kohr
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Chi Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Kevin A Harnden
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Jermaine L Jenkins
- Structural Biology and Biophysics Facility, University of Rochester Medical Center, Rochester, New York 14642
| | - Wayne C Guida
- Department of Chemistry, University of South Florida, Tampa, Florida 336204
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801.,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Rutilio A Fratti
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 .,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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20
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Kornfeld DS. Research misconduct, NSF v NIH: Its nature and prevalence and the impact of their respective methods of investigation and adjudication. Account Res 2019; 26:369-378. [PMID: 31324124 DOI: 10.1080/08989621.2019.1646644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The National Science Foundation (NSF) and the National Institutes of Health (NIH) have established separate administrative mechanisms for investigation and adjudication of alleged research misconduct. This report compares research misconduct at NSF and NIH and the possible effects of their respective methods of investigation and adjudication. Notable and paradoxical findings were identified: NIH supported four times the number of grants as NSF, yet NSF reviewed 2.5 times the number of research misconduct reports. NSF faculty were two-times more likely to be found guilty (88%) than faculty at NIH (42%). 83.6% of NSF offenders were guilty of plagiarism, vs. 4.8% at NIH. NSF trainees made up 6% of the guilty, vs. 42% at NIH. These findings are most likely related to the nature of their respective sciences, scientists, and the nature of their publications. Investigative policies and procedures are quite similar at these two agencies with the exception of the subpoena power available to the NSF's Office of the Inspector General (OIG) where it would be infrequently utilized in investigations of its predominant offense, plagiarism. However, it could prove useful if made available to the NIH Office of Research Integrity (ORI) for investigations of fabrication/falsification, its most common offense. Federal criteria for prosecution should be modified to increase the likelihood of prosecution of serious offenders referred by ORI.
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Affiliation(s)
- Donald S Kornfeld
- Emeritus of Psychiatry, Columbia University College of Physicians and Surgeons , New York , USA
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21
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Gallimore AR, Kim T, Tanaka-Yamamoto K, De Schutter E. Switching On Depression and Potentiation in the Cerebellum. Cell Rep 2019; 22:722-733. [PMID: 29346769 DOI: 10.1016/j.celrep.2017.12.084] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 11/10/2017] [Accepted: 12/22/2017] [Indexed: 12/30/2022] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) in the cerebellum are important for motor learning. However, the signaling mechanisms controlling whether LTD or LTP is induced in response to synaptic stimulation remain obscure. Using a unified model of LTD and LTP at the cerebellar parallel fiber-Purkinje cell (PF-PC) synapse, we delineate the coordinated pre- and postsynaptic signaling that determines the direction of plasticity. We show that LTP is the default response to PF stimulation above a well-defined frequency threshold. However, if the calcium signal surpasses the threshold for CaMKII activation, then an ultrasensitive "on switch" activates an extracellular signal-regulated kinase (ERK)-based positive feedback loop that triggers LTD instead. This postsynaptic feedback loop is sustained by another, trans-synaptic, feedback loop that maintains nitric oxide production throughout LTD induction. When full depression is achieved, an automatic "off switch" inactivates the feedback loops, returning the network to its basal state and demarcating the end of the early phase of LTD.
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Affiliation(s)
- Andrew R Gallimore
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
| | - Taegon Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Keiko Tanaka-Yamamoto
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Erik De Schutter
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
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22
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Sparks RP, Jenkins JL, Fratti R. Use of Surface Plasmon Resonance (SPR) to Determine Binding Affinities and Kinetic Parameters Between Components Important in Fusion Machinery. Methods Mol Biol 2019; 1860:199-210. [PMID: 30317506 DOI: 10.1007/978-1-4939-8760-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Surface plasmon resonance (SPR) can be used to analyze both binding affinities and kinetic parameters between a ligand and an analyte. SPR can be performed by either cross-linking a given ligand to a sensor chip covalently or utilizing high-affinity non-covalent interactions to secure a ligand in a particular conformation to a chip, both of which have their potential advantages. SPR measurements are mass based and reflect the proportional amount of analyte bound to a given ligand at a given concentration when flowed at a set rate in order to determine the binding parameters of a given biochemical interaction. The resultant sensorgram can indicate different types of binding events as well as provide both ka and kd, which can be used to determine an equilibrium dissociation constant KD. SPR can be used to measure binding affinity of proteins involved in fusion such as between SNAREs, SNAREs, and proteins that interact with them such as Sec18 (NSF) or Sec17 (alpha-SNAP), or to measure the binding of any fusion-related protein to a specific lipid or other small molecules; however, KDs are determined by SPR using a titration of concentrations of analyte and a maximum point on the sensorgram signifying saturation of the protein in order to determine a steady-state KD.
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23
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Starr ML, Sparks RP, Arango AS, Hurst LR, Zhao Z, Lihan M, Jenkins JL, Tajkhorshid E, Fratti RA. Phosphatidic acid induces conformational changes in Sec18 protomers that prevent SNARE priming. J Biol Chem 2019; 294:3100-3116. [PMID: 30617180 PMCID: PMC6398130 DOI: 10.1074/jbc.ra118.006552] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [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: 11/02/2018] [Revised: 12/31/2018] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic cell homeostasis requires transfer of cellular components among organelles and relies on membrane fusion catalyzed by SNARE proteins. Inactive SNARE bundles are reactivated by hexameric N-ethylmaleimide-sensitive factor, vesicle-fusing ATPase (Sec18/NSF)-driven disassembly that enables a new round of membrane fusion. We previously found that phosphatidic acid (PA) binds Sec18 and thereby sequesters it from SNAREs and that PA dephosphorylation dissociates Sec18 from the membrane, allowing it to engage SNARE complexes. We now report that PA also induces conformational changes in Sec18 protomers and that hexameric Sec18 cannot bind PA membranes. Molecular dynamics (MD) analyses revealed that the D1 and D2 domains of Sec18 contain PA-binding sites and that the residues needed for PA binding are masked in hexameric Sec18. Importantly, these simulations also disclosed that a major conformational change occurs in the linker region between the D1 and D2 domains, which is distinct from the conformational changes that occur in hexameric Sec18 during SNARE priming. Together, these findings indicate that PA regulates Sec18 function by altering its architecture and stabilizing membrane-bound Sec18 protomers.
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Affiliation(s)
- Matthew L Starr
- From the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Robert P Sparks
- From the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Andres S Arango
- the Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Logan R Hurst
- From the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Zhiyu Zhao
- the Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Muyun Lihan
- the Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Jermaine L Jenkins
- the Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York 14642
| | - Emad Tajkhorshid
- From the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- the Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, and
| | - Rutilio A Fratti
- From the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801,
- the Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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Poe AR, Wang B, Sapar ML, Ji H, Li K, Onabajo T, Fazliyeva R, Gibbs M, Qiu Y, Hu Y, Han C. Robust CRISPR/Cas9-Mediated Tissue-Specific Mutagenesis Reveals Gene Redundancy and Perdurance in Drosophila. Genetics 2019; 211:459-472. [PMID: 30504366 PMCID: PMC6366929 DOI: 10.1534/genetics.118.301736] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [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: 10/27/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022] Open
Abstract
Tissue-specific loss-of-function (LOF) analysis is essential for characterizing gene function. Here, we present a simple, yet highly efficient, clustered regularly interspaced short palindromic repeats (CRISPR)-mediated tissue-restricted mutagenesis (CRISPR-TRiM) method for ablating gene function in Drosophila This binary system consists of a tissue-specific Cas9 and a ubiquitously expressed multi-guide RNA (gRNA) transgene. We describe convenient toolkits for making enhancer-driven Cas9 lines and multi-gRNAs that are optimized for mutagenizing somatic cells. We demonstrate that insertions or deletions in coding sequences more reliably cause somatic mutations than DNA excisions induced by two gRNAs. We further show that enhancer-driven Cas9 is less cytotoxic yet results in more complete LOF than Gal4-driven Cas9 in larval sensory neurons. Finally, CRISPR-TRiM efficiently unmasks redundant soluble N-ethylmaleimide-sensitive factor attachment protein receptor gene functions in neurons and epidermal cells. Importantly, Cas9 transgenes expressed at different times in the neuronal lineage reveal the extent to which gene products persist in cells after tissue-specific gene knockout. These CRISPR tools can be applied to analyze tissue-specific gene function in many biological processes.
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Affiliation(s)
- Amy R Poe
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Maria L Sapar
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Hui Ji
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Kailyn Li
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Tireniolu Onabajo
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Rushaniya Fazliyeva
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Mary Gibbs
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Yue Qiu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Yuzhao Hu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
| | - Chun Han
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853
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25
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Abstract
Intracellular membrane fusion mediates material and information exchange among different cells or cellular compartments with high accuracy and spatiotemporal resolution. Fusion is driven by ordered folding and assembly of soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptors (SNAREs) and regulated by many other proteins. Understanding regulated SNARE assembly is key to dissecting mechanisms and physiologies of various fusion processes and their associated diseases. Yet, it remains challenging to study regulated SNARE assembly using traditional ensemble-based experimental approaches. Here, we describe our new method to measure the energy and kinetics of neuronal SNARE assembly in the presence of α-SNAP, using a single-molecule manipulation approach based on high-resolution optical tweezers. Detailed experimental protocols and methods of data analysis are shown. This approach can be widely applied to elucidate the effects of regulatory proteins on SNARE assembly and membrane fusion.
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Affiliation(s)
- Lu Ma
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Junyi Jiao
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Integrated Graduate Program in Physical and Engineering Biology, New Haven, CT, USA
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
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26
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Abstract
Microscale thermophoresis is a relatively new technique used by an increasing number of academic laboratories to estimate relative binding affinities between ligand (analyte) that is titrated and a target (generally protein) that is either fluorescently labeled exogenously in the red or blue channel (labeled thermophoresis) or endogenously labeled via the presence of sufficient aromatic amino acid residues such as tryptophan (label-free thermophoresis). There are advantages and disadvantages to each technique; however, one major disadvantage of label-free thermophoresis is that protein-protein interactions cannot be measured, as generally most proteins have enough aromatic residues to generate an interfering signal. Thermophoresis can be used to determine steady-state binding affinities as between SNAREs and relevant binding partners of SNAREs and labeled thermophoresis is increasingly becoming a reliable technique to screen binding partners of fusion machinery to determine relevance in terms of direct biochemical interactions.
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27
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Clases D, Fingerhut S, Jeibmann A, Sperling M, Doble P, Karst U. LA-ICP-MS/MS improves limits of detection in elemental bioimaging of gadolinium deposition originating from MRI contrast agents in skin and brain tissues. J Trace Elem Med Biol 2019; 51:212-218. [PMID: 30466933 DOI: 10.1016/j.jtemb.2018.10.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [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: 06/25/2018] [Revised: 09/18/2018] [Accepted: 10/29/2018] [Indexed: 10/28/2022]
Abstract
A novel analytical method to detect the retention of gadolinium from contrast agents for magnetic resonance imaging (MRI) in tissue samples of patients is presented. It is based on laser ablation - inductively coupled plasma - triple quadrupole - mass spectrometry (LA-ICP-MS/MS). Both Gd and P were monitored with a mass shift of +16, corresponding to mono-oxygenated species, as well as Zn, Ca, and Fe on-mass. This method resulted in a significantly reduced background and improved limits of detection not only for phosphorus, but also for gadolinium. These improvements were essential to perform elemental bioimaging with improved resolution of 5 μm x 5 μm, allowing the detection of small Gd deposits in fibrotic skin and brain tumour tissue with diameters of approximately 50 μm. Detailed analyses of these regions revealed that most Gd was accompanied with P and Ca, indicating co-precipitation.
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Affiliation(s)
- David Clases
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 30, 48149, Münster, Germany; Elemental Bioimaging Facility, University of Technology Sydney, Broadway, 2007, NSW, Australia
| | - Stefanie Fingerhut
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 30, 48149, Münster, Germany
| | - Astrid Jeibmann
- University Hospital Münster, Institute of Neuropathology, Pottkamp 2, 48149, Münster, Germany
| | - Michael Sperling
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 30, 48149, Münster, Germany; European Virtual Institute for Speciation Analysis (EVISA), Mendelstraße 11, 48149, Münster, Germany
| | - Philip Doble
- Elemental Bioimaging Facility, University of Technology Sydney, Broadway, 2007, NSW, Australia
| | - Uwe Karst
- University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 30, 48149, Münster, Germany.
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28
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Cao F, Zhou Z, Cai S, Xie W, Jia Z. Hippocampal Long-Term Depression in the Presence of Calcium-Permeable AMPA Receptors. Front Synaptic Neurosci 2018; 10:41. [PMID: 30483111 PMCID: PMC6242858 DOI: 10.3389/fnsyn.2018.00041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/22/2018] [Indexed: 11/28/2022] Open
Abstract
The GluA2 subunit of AMPA glutamate receptors (AMPARs) has been shown to be critical for the expression of NMDA receptor (NMDAR)-dependent long-term depression (LTD). However, in young GluA2 knockout (KO) mice, this form of LTD can still be induced in the hippocampus, suggesting that LTD mechanisms may be modified in the presence of GluA2-lacking, Ca2+ permeable AMPARs. In this study, we examined LTD at the CA1 synapse in GluA2 KO mice by using several well-established inhibitory peptides known to block LTD in wild type (WT) rodents. We showed that while LTD in the KO mice is still blocked by the protein interacting with C kinase 1 (PICK1) peptide pepEVKI, it becomes insensitive to the N-ethylmaleimide-sensitive factor (NSF) peptide pep2m. In addition, the effects of actin and cofilin inhibitory peptides were also altered. These results indicate that in the absence of GluA2, LTD expression mechanisms are different from those in WT animals, suggesting that there are multiple molecular processes enabling LTD expression that are adaptable to physiological and genetic manipulations.
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Affiliation(s)
- Feng Cao
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zikai Zhou
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada.,The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.,The Collaborative Innovation Center for Brain Science, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Sammy Cai
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.,The Collaborative Innovation Center for Brain Science, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Zhengping Jia
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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29
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Starr ML, Fratti R. Determination of Sec18-Lipid Interactions by Liposome-Binding Assay. Methods Mol Biol 2019; 1860:211-20. [PMID: 30317507 DOI: 10.1007/978-1-4939-8760-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Protein-lipid binding interactions play a key role in the regulation of peripheral membrane protein function. Liposome-binding assays are a simple and affordable means of screening for specific protein-lipid interactions. Liposomes are prepared by mixing phospholipid combinations of interest before drying and rehydration. Sonication of the lipid mixture produces small unilamellar vesicles (SUVs) which are incubated with a protein of interest to allow for any binding to occur. Liposomes and liposome-protein complexes are floated on a sucrose gradient by centrifugation to separate them from unbound protein. Bound protein levels are easily determined by SDS-PAGE and Western blotting. This approach provides a reliable means of assaying novel protein-lipid interactions in vitro. Here we use liposome floatation to show the binding of the SNARE-activating protein Sec18 (mammalian NSF) to phosphatidic acid.
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30
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Datta SP, Jana K, Mondal A, Ganguly S, Sarkar S. Multiple paralogues of α-SNAP in Giardia lamblia exhibit independent subcellular localization and redistribution during encystation and stress. Parasit Vectors 2018; 11:539. [PMID: 30286802 PMCID: PMC6172762 DOI: 10.1186/s13071-018-3112-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/13/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The differently-diverged parasitic protist Giardia lamblia is known to have minimal machinery for vesicular transport. Yet, it has three paralogues of SNAP, a crucial component that together with NSF brings about disassembly of the cis-SNARE complex formed following vesicle fusion to target membranes. Given that most opisthokont hosts of this gut parasite express only one α-SNAP, this study was undertaken to determine whether these giardial SNAP proteins have undergone functional divergence. RESULTS All three SNAP paralogues are expressed in trophozoites, encysting trophozoites and cysts. Even though one of them clusters with γ-SNAP sequences in a phylogenetic tree, functional complementation analysis in yeast indicates that all the three proteins are functionally orthologous to α-SNAP. Localization studies showed a mostly non-overlapping distribution of these α-SNAPs in trophozoites, encysting cells and cysts. In addition, two of the paralogues exhibit substantial subcellular redistribution during encystation, which was also seen following exposure to oxidative stress. However, the expression of the three genes remained unchanged during this redistribution process. There is also a difference in the affinity of each of these α-SNAP paralogues for GlNSF. CONCLUSIONS None of the genes encoding the three α-SNAPs are pseudogenes and the encoded proteins are likely to discharge non-redundant functions in the different morphological states of G. lamblia. Based on the difference in the interaction of individual α-SNAPs with GlNSF and their non-overlapping pattern of subcellular redistribution during encystation and under stress conditions, it may be concluded that the three giardial α-SNAP paralogues have undergone functional divergence. Presence of one of the giardial α-SNAPs at the PDRs of flagella, where neither GlNSF nor any of the SNAREs localize, indicates that this α-SNAP discharges a SNARE-independent role in this gut pathogen.
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Affiliation(s)
- Shankari Prasad Datta
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India
| | - Avisek Mondal
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India.,Present Address: Section on Developmental Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Sandipan Ganguly
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Srimonti Sarkar
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India.
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31
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Lanning NJ, VanOpstall C, Goodall ML, MacKeigan JP, Looyenga BD. LRRK2 deficiency impairs trans-Golgi to lysosome trafficking and endocytic cargo degradation in human renal proximal tubule epithelial cells. Am J Physiol Renal Physiol 2018; 315:F1465-F1477. [PMID: 30089035 DOI: 10.1152/ajprenal.00009.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Defects in vesicular trafficking underlie a wide variety of human diseases. Genetic disruption of leucine-rich repeat kinase 2 (LRRK2) in rodents results in epithelial vesicular trafficking errors that can also be induced by treatment of animals with LRRK2 kinase inhibitors. Here we demonstrate that defects in human renal cells lacking LRRK2 phenocopy those seen in the kidneys of Lrrk2 knockout mice, characterized by accumulation of intracellular waste vesicles and fragmentation of the Golgi apparatus. This phenotype can be recapitulated by knockdown of N-ethylmaleimide-sensitive factor, which physically associates with LRRK2 in renal cells. Deficiency in either protein leads to a defect in trans-Golgi to lysosome protein trafficking, which compromises the capacity of lysosomes to degrade endocytic and autophagic cargo. In contrast, neither bulk endocytosis nor autophagic flux are impaired when LRRK2 is acutely knocked down in normal immortalized human kidney (HK2) cells. These data collectively suggest that the primary renal defect caused by LRRK2 deficiency is in protein trafficking between the Golgi apparatus and late endosome/lysosome, which leads to progressive impairments in lysosomal function.
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Affiliation(s)
- Nathan J Lanning
- Van Andel Research Institute, Lab of Systems Biology , Grand Rapids, Michigan
| | - Calvin VanOpstall
- Calvin College, Department of Chemistry and Biochemistry , Grand Rapids, Michigan
| | - Megan L Goodall
- Van Andel Research Institute, Lab of Systems Biology , Grand Rapids, Michigan
| | - Jeffrey P MacKeigan
- Van Andel Research Institute, Lab of Systems Biology , Grand Rapids, Michigan
| | - Brendan D Looyenga
- Van Andel Research Institute, Lab of Systems Biology , Grand Rapids, Michigan.,Calvin College, Department of Chemistry and Biochemistry , Grand Rapids, Michigan
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32
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Abstract
Research for three decades and major recent advances have provided crucial insights into how neurotransmitters are released by Ca2+ -triggered synaptic vesicle exocytosis, leading to reconstitution of basic steps that underlie Ca2+ -dependent membrane fusion and yielding a model that assigns defined functions for central components of the release machinery. The soluble N-ethyl maleimide sensitive factor attachment protein receptors (SNAREs) syntaxin-1, SNAP-25, and synaptobrevin-2 form a tight SNARE complex that brings the vesicle and plasma membranes together and is key for membrane fusion. N-ethyl maleimide sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) disassemble the SNARE complex to recycle the SNAREs for another round of fusion. Munc18-1 and Munc13-1 orchestrate SNARE complex formation in an NSF-SNAP-resistant manner by a mechanism whereby Munc18-1 binds to synaptobrevin and to a self-inhibited "closed" conformation of syntaxin-1, thus forming a template to assemble the SNARE complex, and Munc13-1 facilitates assembly by bridging the vesicle and plasma membranes and catalyzing opening of syntaxin-1. Synaptotagmin-1 functions as the major Ca2+ sensor that triggers release by binding to membrane phospholipids and to the SNAREs, in a tight interplay with complexins that accelerates membrane fusion. Many of these proteins act as both inhibitors and activators of exocytosis, which is critical for the exquisite regulation of neurotransmitter release. It is still unclear how the actions of these various proteins and multiple other components that control release are integrated and, in particular, how they induce membrane fusion, but it can be expected that these fundamental questions can be answered in the near future, building on the extensive knowledge already available.
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Affiliation(s)
- Josep Rizo
- Departments of Biophysics, Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390
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33
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Schieda N, Blaichman JI, Costa AF, Glikstein R, Hurrell C, James M, Jabehdar Maralani P, Shabana W, Tang A, Tsampalieros A, van der Pol CB, Hiremath S. Gadolinium-Based Contrast Agents in Kidney Disease: A Comprehensive Review and Clinical Practice Guideline Issued by the Canadian Association of Radiologists. Can J Kidney Health Dis 2018; 5:2054358118778573. [PMID: 29977584 PMCID: PMC6024496 DOI: 10.1177/2054358118778573] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/31/2018] [Indexed: 12/29/2022] Open
Abstract
PURPOSE OF REVIEW Use of gadolinium-based contrast agents (GBCA) in renal impairment is controversial, with physician and patient apprehension in acute kidney injury (AKI), chronic kidney disease (CKD), and dialysis because of concerns regarding nephrogenic systemic fibrosis (NSF). The position that GBCA are absolutely contraindicated in AKI, category G4 and G5 CKD (estimated glomerular filtration rate [eGFR] < 30 mL/min/1.73 m2), and dialysis-dependent patients is outdated and may limit access to clinically necessary contrast-enhanced magnetic resonance imaging (MRI) examinations. This review and clinical practice guideline addresses the discrepancy between existing Canadian guidelines regarding use of GBCA in renal impairment and NSF. SOURCES OF INFORMATION Published literature (including clinical trials, retrospective cohort series, review articles, and case reports), online registries, and direct manufacturer databases were searched for reported cases of NSF by class and specific GBCA and exposed patient population. METHODS A comprehensive review was conducted identifying cases of NSF and their association to class of GBCA, specific GBCA used, patient, and dose (when this information was available). Based on the available literature, consensus guidelines were developed by an expert panel of radiologists and nephrologists. KEY FINDINGS In patients with category G2 or G3 CKD (eGFR ≥ 30 and < 60 mL/min/1.73 m2), administration of standard doses of GBCA is safe and no additional precautions are necessary. In patients with AKI, with category G4 or G5 CKD (eGFR < 30 mL/min/1.73 m2) or on dialysis, administration of GBCA should be considered individually and alternative imaging modalities utilized whenever possible. If GBCA are necessary, newer GBCA may be administered with patient consent obtained by a physician (or their delegate) citing an exceedingly low risk (much less than 1%) of developing NSF. Standard GBCA dosing should be used; half or quarter dosing is not recommended and repeat injections should be avoided. Dialysis-dependent patients should receive dialysis; however, initiating dialysis or switching from peritoneal to hemodialysis to reduce the risk of NSF is unproven. Use of a macrocyclic ionic instead of macrocyclic nonionic GBCA or macrocyclic instead of newer linear GBCA to further prevent NSF is unproven. Gadopentetate dimeglumine, gadodiamide, and gadoversetamide remain absolutely contraindicated in patients with AKI, those with category G4 or G5 CKD, or those on dialysis. The panel agreed that screening for renal disease is important but less critical when using macrocyclic and newer linear GBCA. Monitoring for and reporting of potential cases of NSF in patients with AKI or CKD who have received GBCA is recommended. LIMITATIONS Limited available literature (number of injections and use in renal impairment) regarding the use of gadoxetate disodium. Limited, but growing and generally high-quality, number of clinical trials evaluating GBCA administration in renal impairment. Limited data regarding the topic of Gadolinium deposition in the brain, particularly as it related to patients with renal impairment. IMPLICATIONS In patients with AKI and category G4 and G5 CKD (eGFR < 30 mL/min/1.73 m2) and in dialysis-dependent patients who require GBCA-enhanced MRI, GBCA can be administered with exceedingly low risk of causing NSF when using macrocyclic agents and newer linear agents at routine doses.
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Affiliation(s)
- Nicola Schieda
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada
| | - Jason I. Blaichman
- Faculty of Medicine, Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Andreu F. Costa
- Department of Diagnostic Radiology, Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Rafael Glikstein
- Brain and Mind Research Institute, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
- Neuroradiology Section, MRI Modality Lead, Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada
| | - Casey Hurrell
- Canadian Association of Radiologists, Ottawa, Ontario, Canada
| | - Matthew James
- Cumming School of Medicine, University of Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Alberta, Canada
| | | | - Wael Shabana
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada
| | - An Tang
- Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montreal, Québec, Canada
- Centre de recherche du Centre Hospitalier de l’Université de Montréal, Québec, Canada
| | - Anne Tsampalieros
- Division of Nephrology, Children’s Hospital of Eastern Ontario, Clinical Epidemiology Program and the University of Ottawa, Ontario, Canada
| | | | - Swapnil Hiremath
- Division of Nephrology, Department of Medicine and Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
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34
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Schieda N, Blaichman JI, Costa AF, Glikstein R, Hurrell C, James M, Jabehdar Maralani P, Shabana W, Tang A, Tsampalieros A, van der Pol C, Hiremath S. Gadolinium-Based Contrast Agents in Kidney Disease: Comprehensive Review and Clinical Practice Guideline Issued by the Canadian Association of Radiologists. Can Assoc Radiol J 2018; 69:136-150. [PMID: 29706252 DOI: 10.1016/j.carj.2017.11.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/13/2017] [Indexed: 01/04/2023] Open
Abstract
Use of gadolinium-based contrast agents (GBCAs) in renal impairment is controversial, with physician and patient apprehension in acute kidney injury (AKI), chronic kidney disease (CKD), and dialysis because of concerns regarding nephrogenic systemic fibrosis (NSF). The position that GBCAs are absolutely contraindicated in AKI, CKD stage 4 or 5 (estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m2) and dialysis-dependent patients is outdated, and may limit access to clinically necessary contrast-enhanced MRI examinations. Following a comprehensive review of the literature and reported NSF cases to date, a committee of radiologists and nephrologists developed clinical practice guidelines to assist physicians in making decisions regarding GBCA administrations. In patients with mild-to-moderate CKD (eGFR ≥30 and <60 mL/min/1.73 m2), administration of standard doses of GBCA is safe and no additional precautions are necessary. In patients with AKI, with severe CKD (eGFR <30 mL/min/1.73 m2), or on dialysis, administration of GBCAs should be considered individually and alternative imaging modalities utilized whenever possible. If GBCAs are necessary, newer GBCAs may be administered with patient consent obtained by a physician (or their delegate), citing an exceedingly low risk (much less than 1%) of developing NSF. Standard GBCA dosing should be used; half or quarter dosing is not recommended and repeat injections should be avoided. Dialysis-dependent patients should receive dialysis; however, initiating dialysis or switching from peritoneal to hemodialysis to reduce the risk of NSF is unproven. Use of a macrocyclic ionic instead of macrocyclic nonionic GBCA or macrocyclic instead of newer linear GBCA to further prevent NSF is unproven. Gadopentetate dimeglumine, gadodiamide, and gadoversetamide remain absolutely contraindicated in patients with AKI, with stage 4 or 5 CKD, or on dialysis. The panel agreed that screening for renal disease is important but less critical when using macrocyclic and newer linear GBCAs. Monitoring for and reporting of potential cases of NSF in patients with AKI or CKD who have received GBCAs is recommended.
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Affiliation(s)
- Nicola Schieda
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
| | - Jason I Blaichman
- Department of Radiology, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andreu F Costa
- Department of Diagnostic Radiology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, Nova Scotia, Canada
| | - Rafael Glikstein
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada; Brain and Mind Research Institute, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Casey Hurrell
- Canadian Association of Radiologists, Ottawa, Ontario, Canada
| | - Matthew James
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - Wael Shabana
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada
| | - An Tang
- Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montreal, Montreal, Quebec, Canada; Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Anne Tsampalieros
- Division of Nephrology, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada; Clinical Epidemiology Program, University of Ottawa, Ottawa, Ontario, Canada
| | - Christian van der Pol
- Department of Radiology, Brigham and Women's Hospital, Harvard University, Boston, Massachusetts, USA
| | - Swapnil Hiremath
- Division of Nephrology, Department of Medicine and Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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35
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Bayless AM, Zapotocny RW, Grunwald DJ, Amundson KK, Diers BW, Bent AF. An atypical N-ethylmaleimide sensitive factor enables the viability of nematode-resistant Rhg1 soybeans. Proc Natl Acad Sci U S A 2018; 115:E4512-E4521. [PMID: 29695628 PMCID: PMC5948960 DOI: 10.1073/pnas.1717070115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [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] [Indexed: 02/07/2023] Open
Abstract
N-ethylmaleimide sensitive factor (NSF) and α-soluble NSF attachment protein (α-SNAP) are essential eukaryotic housekeeping proteins that cooperatively function to sustain vesicular trafficking. The "resistance to Heterodera glycines 1" (Rhg1) locus of soybean (Glycine max) confers resistance to soybean cyst nematode, a highly damaging soybean pest. Rhg1 loci encode repeat copies of atypical α-SNAP proteins that are defective in promoting NSF function and are cytotoxic in certain contexts. Here, we discovered an unusual NSF allele (Rhg1-associated NSF on chromosome 07; NSFRAN07 ) in Rhg1+ germplasm. NSFRAN07 protein modeling to mammalian NSF/α-SNAP complex structures indicated that at least three of the five NSFRAN07 polymorphisms reside adjacent to the α-SNAP binding interface. NSFRAN07 exhibited stronger in vitro binding with Rhg1 resistance-type α-SNAPs. NSFRAN07 coexpression in planta was more protective against Rhg1 α-SNAP cytotoxicity, relative to WT NSFCh07 Investigation of a previously reported segregation distortion between chromosome 18 Rhg1 and a chromosome 07 interval now known to contain the Glyma.07G195900 NSF gene revealed 100% coinheritance of the NSFRAN07 allele with disease resistance Rhg1 alleles, across 855 soybean accessions and in all examined Rhg1+ progeny from biparental crosses. Additionally, we show that some Rhg1-mediated resistance is associated with depletion of WT α-SNAP abundance via selective loss of WT α-SNAP loci. Hence atypical coevolution of the soybean SNARE-recycling machinery has balanced the acquisition of an otherwise disruptive housekeeping protein, enabling a valuable disease resistance trait. Our findings further indicate that successful engineering of Rhg1-related resistance in plants will require a compatible NSF partner for the resistance-conferring α-SNAP.
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Affiliation(s)
- Adam M Bayless
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Ryan W Zapotocny
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Derrick J Grunwald
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Kaela K Amundson
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Brian W Diers
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801
| | - Andrew F Bent
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706;
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Qian Y, De Schutter G. Different Effects of NSF and PCE Superplasticizer on Adsorption, Dynamic Yield Stress and Thixotropy of Cement Pastes. Materials (Basel) 2018; 11:ma11050695. [PMID: 29710782 PMCID: PMC5978072 DOI: 10.3390/ma11050695] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 11/27/2022]
Abstract
This study compares the differences and similarities of two types of superplasticizers—NSF (Naphthalene Sulfonate Formaldehyde) and PCE (PolyCarboxylate Ester)—in fresh cement paste systems, in terms of adsorption, dynamic yield stress, and thixotropic index. Results show that with either NSF or PCE addition, the more superplasticizer is added, the more it is adsorbed and the more it remains in the interstitial pore solution. The dynamic yield stress and thixotropic index also decrease with increasing addition the amount of either superplasticizer. However, NSF is less efficient in decreasing the dynamic yield stress than PCE. More importantly, the decreasing patterns of dynamic yield stress and thixotropic index are different with NSF and PCE additions; this is tied to the adsorption and dispersing mechanisms of these two types of superplasticizers.
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Affiliation(s)
- Ye Qian
- Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Technologiepark-Zwijnaarde 904, Ghent 9052, Belgium.
| | - Geert De Schutter
- Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Technologiepark-Zwijnaarde 904, Ghent 9052, Belgium.
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Brown KW, Gessesse B, Butler LJ, MacIntosh DL. Potential Effectiveness of Point-of-Use Filtration to Address Risks to Drinking Water in the United States. Environ Health Insights 2017; 11:1178630217746997. [PMID: 29270018 PMCID: PMC5731620 DOI: 10.1177/1178630217746997] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/16/2017] [Indexed: 05/25/2023]
Abstract
Numerous contemporary incidents demonstrate that conventional control strategies for municipal tap water have limited ability to mitigate exposures to chemicals whose sources are within distribution systems, such as lead, and chemicals that are not removed by standard treatment technologies, such as perfluorooctanoic acid (PFOA)/perfluorooctanesulfonic acid (PFOS). In these situations, point-of-use (POU) controls may be effective in mitigating exposures and managing health risks of chemicals in drinking water, but their potential utility has not been extensively examined. As an initial effort to fill this information gap, we conducted a critical review and analysis of the existing literature and data on the effectiveness of POU drinking water treatment technologies for reducing chemical contaminants commonly found in tap water in the United States. We found that many types of water treatment devices available to consumers in the United States have undergone laboratory testing and often certification for removal of chemical contaminants in tap water, but in most cases their efficacy in actual use has yet to be well characterized. In addition, the few studies of POU devices while "in use" focus on traditional contaminants regulated under the Safe Drinking Water Act, but do not generally consider nontraditional contaminants of concern, such as certain novel human carcinogens, industrial chemicals, pesticides, pharmaceuticals, personal care products, and flame retardants. Nevertheless, the limited information available at present suggests that POU devices can be highly effective when used prophylactically and when deployed in response to contamination incidents. Based on these findings, we identify future areas of research for assessing the ability of POU filters to reduce health-related chemical contaminants distributed through public water systems and private wells.
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Affiliation(s)
| | | | - Lindsey J Butler
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, USA
| | - David L MacIntosh
- Environmental Health & Engineering Inc., Needham, MA, USA
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Abstract
Autophagy, a unique intracellular membrane-trafficking pathway, is initiated by the formation of an isolation membrane (phagophore) that engulfs cytoplasmic constituents, leading to generation of the autophagosome, a double-membrane vesicle, which is targeted to the lysosome. The outer autophagosomal membrane consequently fuses with the lysosomal membrane. Multiple membrane-fusion events mediated by SNARE molecules have been postulated to promote autophagy. αSNAP, the adaptor molecule for the SNARE-priming enzyme N-ethylmaleimide-sensitive factor (NSF) is known to be crucial for intracellular membrane fusion processes, but its role in autophagy remains unclear. Here we demonstrated that knockdown of αSNAP leads to inhibition of autophagy, manifested by an accumulation of sealed autophagosomes located in close proximity to lysosomes but not fused with them. Under these conditions, moreover, association of both Atg9 and the autophagy-related SNARE protein syntaxin17 with the autophagosome remained unaffected. Finally, our results suggested that under starvation conditions, the levels of αSNAP, although low, are nevertheless sufficient to partially promote the SNARE priming required for autophagy. Taken together, these findings indicate that while autophagosomal-lysosomal membrane fusion is sensitive to inhibition of SNARE priming, the initial stages of autophagosome biogenesis and autophagosome expansion remain resistant to its loss.
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Affiliation(s)
- Adi Abada
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Smadar Levin-Zaidman
- Department of Chemical Research Support, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Ziv Porat
- Life Sciences Core Facilities, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Tali Dadosh
- Department of Chemical Research Support, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Zvulun Elazar
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel;
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Guo Y, Yue Q, Gao J, Wang Z, Chen YR, Blissard GW, Liu TX, Li Z. Roles of Cellular NSF Protein in Entry and Nuclear Egress of Budded Virions of Autographa californica Multiple Nucleopolyhedrovirus. J Virol 2017; 91:e01111-17. [PMID: 28747507 DOI: 10.1128/JVI.01111-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 07/20/2017] [Indexed: 02/03/2023] Open
Abstract
In eukaryotic cells, the soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) proteins comprise the minimal machinery that triggers fusion of transport vesicles with their target membranes. Comparative studies revealed that genes encoding the components of the SNARE system are highly conserved in yeast, insect, and human genomes. Upon infection of insect cells by the virus Autographa californica multiple nucleopolyhedrovirus (AcMNPV), the transcript levels of most SNARE genes initially were upregulated. We found that overexpression of dominant-negative (DN) forms of NSF or knockdown of the expression of NSF, the key regulator of the SNARE system, significantly affected infectious AcMNPV production. In cells expressing DN NSF, entering virions were trapped in the cytoplasm or transported to the nucleus with low efficiency. The presence of DN NSF also moderately reduced trafficking of the viral envelope glycoprotein GP64 to the plasma membrane but dramatically inhibited production of infectious budded virions (BV). Transmission electron microscopy analysis of infections in cells expressing DN NSF revealed that progeny nucleocapsids were retained in a perinuclear space surrounded by inner and outer nuclear membranes. Several baculovirus conserved (core) proteins (Ac76, Ac78, GP41, Ac93, and Ac103) that are important for infectious budded virion production were found to associate with NSF, and NSF was detected within the assembled BV. Together, these data indicate that the cellular SNARE system is involved in AcMNPV infection and that NSF is required for efficient entry and nuclear egress of budded virions of AcMNPV.IMPORTANCE Little is known regarding the complex interplay between cellular factors and baculoviruses during viral entry and egress. Here, we examined the cellular SNARE system, which mediates the fusion of vesicles in healthy cells, and its relation to baculovirus infection. Using a DN approach and RNA interference knockdown, we demonstrated that a general disruption of the SNARE machinery significantly inhibited the production of infectious BV of AcMNPV. The presence of a DN NSF protein resulted in low-efficiency entry of BV and the retention of progeny nucleocapsids in the perinuclear space during egress. Combined with these effects, we also found that several conserved (core) baculovirus proteins closely associate with NSF, and these results suggest their involvement in the egress of BV. Our findings are the first to demonstrate that the SNARE system is required for efficient entry of BV and nuclear egress of progeny nucleocapsids of baculoviruses.
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Beam AS, Moore KG, Gillis SN, Ford KF, Gray T, Steinwinder AH, Graham A. GBCAs and Risk for Nephrogenic Systemic Fibrosis: A Literature Review. Radiol Technol 2017; 88:583-589. [PMID: 28900045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE To examine the risks of using of gadolinium-based contrast agents (GBCAs) in magnetic resonance (MR) imaging and explore strategies to reduce the likeliness of adverse effects in patients who might be at risk for developing nephrogenic system fibrosis (NSF). METHODS A search of 3 scholarly databases was performed to identify articles that discuss adverse reactions to GBCAs, specifically relating to kidney function, in MR examinations. A total of 20 peer-reviewed articles were analyzed. DISCUSSION Safety of contrast media is related to the stability of the chelate bond (ie, macrocyclic or linear). Patients who have decreased kidney function or chronic kidney disease are at higher risk for an adverse reaction to GBCAs; typically, macrocyclic contrast agents are considered safer than linear contrast agents for patients at risk for developing NSF because of their higher kinetic stability. Recommended doses of gadolinium should be adhered to carefully for all patients in conjunction with the glomerular filtration rate guidelines for contrast administration defined by the American College of Radiology. CONCLUSION Although there are advantages to contrast use in MR examinations, technologists should work closely with referring physicians and radiologists to minimize risks for developing NSF in patients who have decreased kidney function.
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Jakhanwal S, Lee CT, Urlaub H, Jahn R. An activated Q-SNARE/SM protein complex as a possible intermediate in SNARE assembly. EMBO J 2017; 36:1788-1802. [PMID: 28483813 DOI: 10.15252/embj.201696270] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 01/15/2023] Open
Abstract
Assembly of the SNARE proteins syntaxin1, SNAP25, and synaptobrevin into a SNARE complex is essential for exocytosis in neurons. For efficient assembly, SNAREs interact with additional proteins but neither the nature of the intermediates nor the sequence of protein assembly is known. Here, we have characterized a ternary complex between syntaxin1, SNAP25, and the SM protein Munc18-1 as a possible acceptor complex for the R-SNARE synaptobrevin. The ternary complex binds synaptobrevin with fast kinetics, resulting in the rapid formation of a fully zippered SNARE complex to which Munc18-1 remains tethered by the N-terminal domain of syntaxin1. Intriguingly, only one of the synaptobrevin truncation mutants (Syb1-65) was able to bind to the syntaxin1:SNAP25:Munc18-1 complex, suggesting either a cooperative zippering mechanism that proceeds bidirectionally or the progressive R-SNARE binding via an SM template. Moreover, the complex is resistant to disassembly by NSF Based on these findings, we consider the ternary complex as a strong candidate for a physiological intermediate in SNARE assembly.
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Affiliation(s)
- Shrutee Jakhanwal
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Chung-Tien Lee
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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Ryu JK, Jahn R, Yoon TY. Review: Progresses in understanding N-ethylmaleimide sensitive factor ( NSF) mediated disassembly of SNARE complexes. Biopolymers 2017; 105:518-31. [PMID: 27062050 DOI: 10.1002/bip.22854] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/19/2016] [Accepted: 04/06/2016] [Indexed: 11/09/2022]
Abstract
N-ethylmaleimide sensitive factor (NSF) is a key protein of intracellular membrane traffic. NSF is a highly conserved protein belonging to the ATPases associated with other activities (AAA+ proteins). AAA+ share common domains and all transduce ATP hydrolysis into major conformational movements that are used to carry out conformational work on client proteins. Together with its cofactor SNAP, NSF is specialized on disassembling highly stable SNARE complexes that form after each membrane fusion event. Although essential for all eukaryotic cells, however, the details of this reaction have long been enigmatic. Recently, major progress has been made in both elucidating the structure of NSF/SNARE complexes and in understanding the reaction mechanism. Advances in both cryo EM and single molecule measurements suggest that NSF, together with its cofactor SNAP, imposes a tight grip on the SNARE complex. After ATP hydrolysis and phosphate release, it then builds up mechanical tension that is ultimately used to rip apart the SNAREs in a single burst. Because the AAA domains are extremely well-conserved, the molecular mechanism elucidated for NSF is presumably shared by many other AAA+ ATPases. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 518-531, 2016.
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Affiliation(s)
- Je-Kyung Ryu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, CJ, 2628, the Netherlands
| | - Reinhard Jahn
- Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, 37077, Germany
| | - Tae-Young Yoon
- Center for Nanomedicine, Institute for Basic Science (IBS) and Y-IBS Institute, Yonsei University, Seoul, 03722, South Korea
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Selvakumar D, Drescher MJ, Deckard NA, Ramakrishnan NA, Morley BJ, Drescher DG. Dopamine D1A directly interacts with otoferlin synaptic pathway proteins: Ca2+ and phosphorylation underlie an NSF-to-AP2mu1 molecular switch. Biochem J 2017; 474:79-104. [PMID: 27821621 PMCID: PMC6310132 DOI: 10.1042/bcj20160690] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 07/19/2016] [Revised: 10/15/2016] [Accepted: 11/07/2016] [Indexed: 11/17/2022]
Abstract
Dopamine receptors regulate exocytosis via protein-protein interactions (PPIs) as well as via adenylyl cyclase transduction pathways. Evidence has been obtained for PPIs in inner ear hair cells coupling D1A to soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE)-related proteins snapin, otoferlin, N-ethylmaleimide-sensitive factor (NSF), and adaptor-related protein complex 2, mu 1 (AP2mu1), dependent on [Ca2+] and phosphorylation. Specifically, the carboxy terminus of dopamine D1A was found to directly bind t-SNARE-associated protein snapin in teleost and mammalian hair cell models by yeast two-hybrid (Y2H) and pull-down assays, and snapin directly interacts with hair cell calcium-sensor otoferlin. Surface plasmon resonance (SPR) analysis, competitive pull-downs, and co-immunoprecipitation indicated that these interactions were promoted by Ca2+ and occur together. D1A was also found to separately interact with NSF, but with an inverse dependence on Ca2+ Evidence was obtained, for the first time, that otoferlin domains C2A, C2B, C2D, and C2F interact with NSF and AP2mu1, whereas C2C or C2E do not bind to either protein, representing binding characteristics consistent with respective inclusion or omission in individual C2 domains of the tyrosine motif YXXΦ. In competitive pull-down assays, as predicted by KD values from SPR (+Ca2+), C2F pulled down primarily NSF as opposed to AP2mu1. Phosphorylation of AP2mu1 gave rise to a reversal: an increase in binding by C2F to phosphorylated AP2mu1 was accompanied by a decrease in binding to NSF, consistent with a molecular switch for otoferlin from membrane fusion (NSF) to endocytosis (AP2mu1). An increase in phosphorylated AP2mu1 at the base of the cochlear inner hair cell was the observed response elicited by a dopamine D1A agonist, as predicted.
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Affiliation(s)
- Dakshnamurthy Selvakumar
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A
| | - Marian J Drescher
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A.
| | - Nathan A Deckard
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A
| | - Neeliyath A Ramakrishnan
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A
| | - Barbara J Morley
- Boys Town National Research Hospital, Omaha, Nebraska 68131, U.S.A
| | - Dennis G Drescher
- Laboratory of Bio-otology, Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A
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Kienle N, Kloepper TH, Fasshauer D. Shedding light on the expansion and diversification of the Cdc48 protein family during the rise of the eukaryotic cell. BMC Evol Biol 2016; 16:215. [PMID: 27756227 PMCID: PMC5070193 DOI: 10.1186/s12862-016-0790-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 10/04/2016] [Indexed: 11/22/2022] Open
Abstract
Background A defining feature of eukaryotic cells is the presence of various distinct membrane-bound compartments with different metabolic roles. Material exchange between most compartments occurs via a sophisticated vesicle trafficking system. This intricate cellular architecture of eukaryotes appears to have emerged suddenly, about 2 billion years ago, from much less complex ancestors. How the eukaryotic cell acquired its internal complexity is poorly understood, partly because no prokaryotic precursors have been found for many key factors involved in compartmentalization. One exception is the Cdc48 protein family, which consists of several distinct classical ATPases associated with various cellular activities (AAA+) proteins with two consecutive AAA domains. Results Here, we have classified the Cdc48 family through iterative use of hidden Markov models and tree building. We found only one type, Cdc48, in prokaryotes, although a set of eight diverged members that function at distinct subcellular compartments were retrieved from eukaryotes and were probably present in the last eukaryotic common ancestor (LECA). Pronounced changes in sequence and domain structure during the radiation into the LECA set are delineated. Moreover, our analysis brings to light lineage-specific losses and duplications that often reflect important biological changes. Remarkably, we also found evidence for internal duplications within the LECA set that probably occurred during the rise of the eukaryotic cell. Conclusions Our analysis corroborates the idea that the diversification of the Cdc48 family is closely intertwined with the development of the compartments of the eukaryotic cell. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0790-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nickias Kienle
- Département des neurosciences fondamentales, Université de Lausanne, Rue du Bugnon 9, CH-1005, Lausanne, Switzerland
| | - Tobias H Kloepper
- Sir William Dunn School of Pathology, Research Group Cell Biology of Intercellular Signaling, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Dirk Fasshauer
- Département des neurosciences fondamentales, Université de Lausanne, Rue du Bugnon 9, CH-1005, Lausanne, Switzerland.
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Cao F, Zhou Z, Pan X, Leung C, Xie W, Collingridge G, Jia Z. Developmental regulation of hippocampal long-term depression by cofilin-mediated actin reorganization. Neuropharmacology 2016; 112:66-75. [PMID: 27543417 DOI: 10.1016/j.neuropharm.2016.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [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: 06/13/2016] [Revised: 08/15/2016] [Accepted: 08/15/2016] [Indexed: 01/16/2023]
Abstract
Long lasting synaptic plasticity involves both functional and morphological changes, but how these processes are molecularly linked to achieve coordinated plasticity remains poorly understood. Cofilin is a common target of multiple signaling pathways at the synapse and is required for both functional and spine plasticity, but how it is regulated is unclear. In this study, we investigate whether the involvement of cofilin in plasticity is developmentally regulated by examining the role of cofilin in hippocampal long-term depression (LTD) in both young (2 weeks) and mature (2 months) mice. We show that both total protein level of cofilin and its activation undergo significant changes as the brain matures, so that although the amount of cofilin decreases significantly in mature mice, its regulation by protein phosphorylation becomes increasingly important. Consistent with these biochemical data, we show that cofilin-mediated actin reorganization is essential for LTD in mature, but not in young mice. In contrast to cofilin, the GluA2 interactions with NSF and PICK1 appear to be required in both young and mature mice, indicating that AMPAR internalization is a common key mechanism for LTD expression regardless of the developmental stages. These results establish the temporal specificity of cofilin in LTD regulation and suggest that cofilin-mediated actin reorganization may serve as a key mechanism underlying developmental regulation of synaptic and spine plasticity. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.
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Affiliation(s)
- Feng Cao
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Canada; The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing 210096, China
| | - Zikai Zhou
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada; The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing 210096, China; Institute of Life Sciences, The Collaborative Innovation Center for Brain Science, Southeast University, Nanjing 210096, China
| | - Xingxiu Pan
- The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing 210096, China
| | - Celeste Leung
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Canada
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing 210096, China; Institute of Life Sciences, The Collaborative Innovation Center for Brain Science, Southeast University, Nanjing 210096, China
| | - Graham Collingridge
- Department of Physiology, Faculty of Medicine, University of Toronto, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Canada; Centre for Synaptic Plasticity, School of Physiology & Pharmacology, University of Bristol, UK
| | - Zhengping Jia
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Canada.
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Abstract
Nearly 90 % of allegations of biomedical research misconduct in the United States are dismissed by responsible institutions without any faculty assessment or auditable record. Recently, members of the U.S. Congress have complained that the penalties for those against whom findings of research misconduct are made are too light and that too few grant funds associated with research misconduct have been recovered for use by other researchers and taxpayers. Here we discuss the laws that empower federal agencies that can oversee investigations of biomedical research misconduct: the Office of Research Integrity (ORI) and the Office of the Inspector General (OIG), both located within the Department of Health and Human Services (HHS). Research misconduct investigations pertaining to U.S. physical sciences funded through the National Science Foundation (NSF) are overseen by the NSF's OIG. While OIGs may provide some improvement over the ORI in the handling of research misconduct, we have found that a much more serious flaw exists which undermines an ability to conduct performance audits of the effectiveness by which allegations of research misconduct are handled in the United States. Specifically, sufficient data do not need to be retained by U.S. research institutions funded by HHS or NSF to allow effective audit of why allegations of research misconduct are dismissed before being seen by faculty inquiry or investigative committees. U.S. federal Generally Accepted Government Auditing Standards (GAGAS/Yellow Book), if applied to the research misconduct oversight process, would allow a determination of whether the handling of allegations of biomedical research misconduct actually functions adequately, and if not, how it might be improved. In particular, we propose that independent, external peer review under GAGAS audit standards should be instituted without delay in assessing the performance of ORI, or any other similarly tasked federal agency, in handling allegations of research misconduct.
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Affiliation(s)
- Lisa Loikith
- Amerandus Research, 1735 Market Street, Suite 3750, Philadelphia, PA 19103 USA
| | - Robert Bauchwitz
- Amerandus Research, 1735 Market Street, Suite 3750, Philadelphia, PA 19103 USA
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Shi X, Halder P, Yavuz H, Jahn R, Shuman HA. Direct targeting of membrane fusion by SNARE mimicry: Convergent evolution of Legionella effectors. Proc Natl Acad Sci U S A 2016; 113:8807-12. [PMID: 27436892 DOI: 10.1073/pnas.1608755113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Legionella pneumophila, the Gram-negative pathogen causing Legionnaires' disease, infects host cells by hijacking endocytic pathways and forming a Legionella-containing vacuole (LCV) in which the bacteria replicate. To promote LCV expansion and prevent lysosomal targeting, effector proteins are translocated into the host cell where they alter membrane traffic. Here we show that three of these effectors [LegC2 (Legionella eukaryotic-like gene C2)/YlfB (yeast lethal factor B), LegC3, and LegC7/YlfA] functionally mimic glutamine (Q)-SNARE proteins. In infected cells, the three proteins selectively form complexes with the endosomal arginine (R)-SNARE vesicle-associated membrane protein 4 (VAMP4). When reconstituted in proteoliposomes, these proteins avidly fuse with liposomes containing VAMP4, resulting in a stable complex with properties resembling canonical SNARE complexes. Intriguingly, however, the LegC/SNARE hybrid complex cannot be disassembled by N-ethylmaleimide-sensitive factor. We conclude that LegCs use SNARE mimicry to divert VAMP4-containing vesicles for fusion with the LCV, thus promoting its expansion. In addition, the LegC/VAMP4 complex avoids the host's disassembly machinery, thus effectively trapping VAMP4 in an inactive state.
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Zheng W. Probing the structural dynamics of the SNARE recycling machine based on coarse-grained modeling. Proteins 2016; 84:1055-66. [PMID: 27090373 DOI: 10.1002/prot.25052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/04/2016] [Accepted: 04/13/2016] [Indexed: 01/05/2023]
Abstract
Membrane fusion in eukaryotes is driven by the formation of a four-helix bundle by three SNARE proteins. To recycle the SNARE proteins, they must be disassembled by the ATPase NSF and four SNAP proteins which together form a 20S supercomplex. Recently, the first high-resolution structures of the NSF (in both ATP and ADP state) and 20S (in four distinct states termed I, II, IIIa, and IIIb) were solved by cryo-electron microscopy (cryo-EM), which have paved the way for structure-driven studies of the SNARE recycling mechanism. To probe the structural dynamics of SNARE disassembly at amino-acid level of details, a systematic coarse-grained modeling based on an elastic network model and related analyses were performed. Our normal mode analysis of NSF, SNARE, and 20S predicted key modes of collective motions that partially account for the observed structural changes, and illuminated how the SNARE complex can be effectively destabilized by untwisting and bending motions of the SNARE complex driven by the amino-terminal domains of NSF in state II. Our flexibility analysis identified regions with high/low flexibility that coincide with key functional sites (such as the NSF-SNAPs-SNARE binding sites). A subset of hotspot residues that control the above collective motions, which will make promising targets for future mutagenesis studies were also identified. Finally, the conformational changes in 20S as induced by the transition of NSF from ATP to ADP state were modeled, and a concerted untwisting motion of SNARE/SNAPs and a sideway flip of two amino-terminal domains were observed. In sum, the findings have offered new structural and dynamic details relevant to the SNARE disassembly mechanism, and will guide future functional studies of the SNARE recycling machinery. Proteins 2016; 84:1055-1066. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Wenjun Zheng
- Department of Physics, State University of New York, Buffalo, New York, 14260
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Nishizaki T. N-Ethylmaleimide Dissociates α7 ACh Receptor from a Complex with NSF and Promotes Its Delivery to the Presynaptic Membrane. Neurochem Res 2016; 41:2043-8. [PMID: 27105867 DOI: 10.1007/s11064-016-1915-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 11/29/2022]
Abstract
N-Ethylmaleimide (NEM)-sensitive factor (NSF) associates with soluble NSF attachment protein (SNAP), that binds to SNAP receptors (SNAREs) including syntaxin, SNAP25, and synaptobrevin. The complex of NSF/SNAP/SNAREs plays a critical role in the regulation of vesicular traffic. The present study investigated NEM-regulated α7 ACh receptor translocation. NSF associated with β-SNAP and the SNAREs syntaxin 1 and synaptobrevin 2 in the rat hippocampus. NSF also associated with the α7 ACh receptor subunit, the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1 and GluA2, and the γ-aminobutyric acid A (GABAA) receptor γ2 subunit. NEM, an inhibitor of NSF, significantly dissociated the α7 ACh receptor subunit from a complex with NSF and increased cell surface localization of the receptor subunit, but such effect was not obtained with the GluA1, GluA2 or γ2 subunits. NEM, alternatively, dissociated synaptobrevin 2 from an assembly of NSF/β-SNAP/syntaxin 1/synaptobrevin 2. NEM significantly increased the rate of nicotine-triggered AMPA receptor-mediated miniature excitatory postsynaptic currents, without affecting the amplitude, in rat hippocampal slices. The results of the present study indicate that NEM releases the α7 ACh receptor subunit and synaptobrevin 2 from an assembly of α7 ACh receptor subunit/NSF/β-SNAP/syntaxin 1/synaptobrevin 2, thereby promoting delivery of the α7 ACh receptor subunit to presynaptic membrane.
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Xiong H, Cassé F, Zhou M, Xiong ZQ, Joels M, Martin S, Krugers HJ. Interactions between N-Ethylmaleimide-sensitive factor and GluA2 contribute to effects of glucocorticoid hormones on AMPA receptor function in the rodent hippocampus. Hippocampus 2016; 26:848-56. [PMID: 26766634 DOI: 10.1002/hipo.22567] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/07/2016] [Accepted: 01/07/2016] [Indexed: 01/12/2023]
Abstract
Glucocorticoid hormones, via activation of their receptors, promote memory consolidation, but the exact underlying mechanisms remain elusive. We examined how corticosterone regulates AMPA receptor (AMPAR) availability in the synapse, which is important for synaptic plasticity and memory formation. Peptides which specifically block the interaction between N-Ethylmaleimide-Sensitive Factor (NSF) and the AMPAR-subunit GluA2 prevented the increase in synaptic transmission and surface expression of AMPARs known to occur after corticosterone application to hippocampal neurons. Combining a live imaging Fluorescence Recovery After Photobleaching (FRAP) approach with the use of the pH-sensitive GFP-AMPAR tagging revealed that this NSF/GluA2 interaction was also essential for the increase of the mobile fraction and reduction of the diffusion of AMPARs after treating hippocampal neurons with corticosterone. We conclude that the interaction between NSF and GluA2 contributes to the effects of corticosterone on AMPAR function. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Hui Xiong
- SILS-CNS, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Frédéric Cassé
- Centre National De La Recherche Scientifique, University of Nice - Sophia-Antipolis Institut De Pharmacologie Moléculaire Et Cellulaire, UMR7275, Valbonne, 06560, France
| | - Ming Zhou
- Institute of Neuroscience, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, 20031, China
| | - Zhi-Qi Xiong
- SILS-CNS, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Marian Joels
- SILS-CNS, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Stéphane Martin
- Centre National De La Recherche Scientifique, University of Nice - Sophia-Antipolis Institut De Pharmacologie Moléculaire Et Cellulaire, UMR7275, Valbonne, 06560, France
| | - Harm J Krugers
- SILS-CNS, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
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