1
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Oatman SR, Reddy JS, Quicksall Z, Carrasquillo MM, Wang X, Liu CC, Yamazaki Y, Nguyen TT, Malphrus K, Heckman M, Biswas K, Nho K, Baker M, Martens YA, Zhao N, Kim JP, Risacher SL, Rademakers R, Saykin AJ, DeTure M, Murray ME, Kanekiyo T, Dickson DW, Bu G, Allen M, Ertekin-Taner N. Genome-wide association study of brain biochemical phenotypes reveals distinct genetic architecture of Alzheimer's disease related proteins. Mol Neurodegener 2023; 18:2. [PMID: 36609403 PMCID: PMC9825010 DOI: 10.1186/s13024-022-00592-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/19/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is neuropathologically characterized by amyloid-beta (Aβ) plaques and neurofibrillary tangles. The main protein components of these hallmarks include Aβ40, Aβ42, tau, phosphor-tau, and APOE. We hypothesize that genetic variants influence the levels and solubility of these AD-related proteins in the brain; identifying these may provide key insights into disease pathogenesis. METHODS Genome-wide genotypes were collected from 441 AD cases, imputed to the haplotype reference consortium (HRC) panel, and filtered for quality and frequency. Temporal cortex levels of five AD-related proteins from three fractions, buffer-soluble (TBS), detergent-soluble (Triton-X = TX), and insoluble (Formic acid = FA), were available for these same individuals. Variants were tested for association with each quantitative biochemical measure using linear regression, and GSA-SNP2 was used to identify enriched Gene Ontology (GO) terms. Implicated variants and genes were further assessed for association with other relevant variables. RESULTS We identified genome-wide significant associations at seven novel loci and the APOE locus. Genes and variants at these loci also associate with multiple AD-related measures, regulate gene expression, have cell-type specific enrichment, and roles in brain health and other neuropsychiatric diseases. Pathway analysis identified significant enrichment of shared and distinct biological pathways. CONCLUSIONS Although all biochemical measures tested reflect proteins core to AD pathology, our results strongly suggest that each have unique genetic architecture and biological pathways that influence their specific biochemical states in the brain. Our novel approach of deep brain biochemical endophenotype GWAS has implications for pathophysiology of proteostasis in AD that can guide therapeutic discovery efforts focused on these proteins.
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Affiliation(s)
- Stephanie R. Oatman
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Joseph S. Reddy
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL USA
| | - Zachary Quicksall
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL USA
| | | | - Xue Wang
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL USA
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Yu Yamazaki
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Thuy T. Nguyen
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Kimberly Malphrus
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Michael Heckman
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL USA
| | - Kristi Biswas
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Kwangsik Nho
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN USA
- School of Informatics and Computing, Indiana University School of Medicine, Indianapolis, IN USA
| | - Matthew Baker
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Yuka A. Martens
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Na Zhao
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Jun Pyo Kim
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN USA
| | - Shannon L. Risacher
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN USA
| | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
- VIB-UA Center for Molecular Neurology, VIB, University of Antwerp, Antwerp, Belgium
| | - Andrew J. Saykin
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN USA
| | - Michael DeTure
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Melissa E. Murray
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - for the Alzheimer’s Disease Neuroimaging Initiative
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL USA
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN USA
- School of Informatics and Computing, Indiana University School of Medicine, Indianapolis, IN USA
- VIB-UA Center for Molecular Neurology, VIB, University of Antwerp, Antwerp, Belgium
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN USA
- Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Birdsall 3, Jacksonville, FL 32224 USA
| | - Dennis W. Dickson
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Mariet Allen
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Nilüfer Ertekin-Taner
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
- Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Birdsall 3, Jacksonville, FL 32224 USA
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2
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Almasieh M, Faris H, Levin LA. Pivotal roles for membrane phospholipids in axonal degeneration. Int J Biochem Cell Biol 2022; 150:106264. [PMID: 35868612 DOI: 10.1016/j.biocel.2022.106264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/16/2022] [Accepted: 07/17/2022] [Indexed: 10/17/2022]
Abstract
Membrane phospholipids are critical components of several signaling pathways. Maintained in a variety of asymmetric distributions, their trafficking across the membrane can be induced by intra-, extra-, and intercellular events. A familiar example is the externalization of phosphatidylserine from the inner leaflet to the outer leaflet in apoptosis, inducing phagocytosis of the soma. Recently, it has been recognized that phospholipids in the axonal membrane may be a signal for axonal degeneration, regeneration, or other processes. This review focuses on key recent developments and areas for ongoing investigations. KEY FACTS: Phosphatidylserine externalization propagates along an axon after axonal injury and is delayed in the Wallerian degeneration slow (WldS) mutant. The ATP8A2 flippase mutant has spontaneous axonal degeneration. Microdomains of axonal degeneration in spheroid bodies have differential externalization of phosphatidylserine and phosphatidylethanolamine. Phospholipid trafficking could represent a mechanism for coordinated axonal degeneration and elimination, i.e. axoptosis, analogous to apoptosis of the cell body.
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Affiliation(s)
- Mohammadali Almasieh
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Hannah Faris
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
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3
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Li RY, Qin Q, Yang HC, Wang YY, Mi YX, Yin YS, Wang M, Yu CJ, Tang Y. TREM2 in the pathogenesis of AD: a lipid metabolism regulator and potential metabolic therapeutic target. Mol Neurodegener 2022; 17:40. [PMID: 35658903 PMCID: PMC9166437 DOI: 10.1186/s13024-022-00542-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane immune receptor that is mainly expressed on microglia in the brain and macrophages in the periphery. Recent studies have identified TREM2 as a risk factor for Alzheimer’s disease (AD). Increasing evidence has shown that TREM2 can affect lipid metabolism both in the central nervous system (CNS) and in the periphery. In the CNS, TREM2 affects the metabolism of cholesterol, myelin, and phospholipids and promotes the transition of microglia into a disease-associated phenotype. In the periphery, TREM2 influences lipid metabolism by regulating the onset and progression of obesity and its complications, such as hypercholesterolemia, atherosclerosis, and nonalcoholic fatty liver disease. All these altered lipid metabolism processes could influence the pathogenesis of AD through several means, including affecting inflammation, insulin resistance, and AD pathologies. Herein, we will discuss a potential pathway that TREM2 mediates lipid metabolism to influence the pathogenesis of AD in both the CNS and periphery. Moreover, we discuss the possibility that TREM2 may be a key factor that links central and peripheral lipid metabolism under disease conditions, including AD. This link may be due to impacts on the integrity of the blood–brain barrier, and we introduce potential pathways by which TREM2 affects the blood–brain barrier. Moreover, we discuss the role of lipids in TREM2-associated treatments for AD. We propose some potential therapies targeting TREM2 and discuss the prospect and limitations of these therapies.
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Affiliation(s)
- Rui-Yang Li
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Qi Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Han-Chen Yang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Ying-Ying Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ying-Xin Mi
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Yun-Si Yin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Meng Wang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Chao-Ji Yu
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China.
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4
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Acosta DM, Mancinelli C, Bracken C, Eliezer D. Post-translational modifications within tau paired helical filament nucleating motifs perturb microtubule interactions and oligomer formation. J Biol Chem 2021; 298:101442. [PMID: 34838590 PMCID: PMC8741514 DOI: 10.1016/j.jbc.2021.101442] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 10/25/2022] Open
Abstract
Post-translationally modified tau is the primary component of tau neurofibrillary tangles, a pathological hallmark of Alzheimer's disease and other tauopathies. Post-translational modifications within the tau microtubule binding domain (MBD), which encompasses two hexapeptide motifs that act as critical nucleating regions for tau aggregation, can potentially modulate tau aggregation as well as interactions with microtubules (MTs) and membranes. Here we characterize the effects of a recently discovered tau PTM, lysine succinylation, on tau-tubulin interactions, and compare these to the effects of two previously reported MBD modifications, lysine acetylation and tyrosine phosphorylation. As generation of site-specific PTMs in proteins is challenging, we used short synthetic peptides to quantify the effects on tubulin binding of three site-specific PTMs located within the PHF6* (residues 275-280) and PHF6 (residues 306-311) hexapeptide motifs: K280 acetylation, Y310 phosphorylation and K311 succinylation. We compared these effects to those observed for MBD PTM-mimetic point mutations K280Q, Y310E and K311E. Finally, we evaluated the effects of these PTM-mimetic mutations on MBD membrane binding and membrane-induced fibril and oligomer formation. We found that all three PTMs perturb tau MT binding, with Y310 phosphorylation exerting the strongest effect. PTM mimetic mutations partially recapitulated the effects of the PTMs on MT binding and also disrupted tau membrane binding and membrane induced oligomer and fibril formation. These results imply that these PTMs, including the novel and AD-specific succinylation of tau K311, may influence both the physiological and pathological interactions of tau and thus represent targets for therapeutic intervention.
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Affiliation(s)
- Diana M Acosta
- Feil Family Brain and Mind Research Institute, Department of Biochemistry and Program in Structural Biology, Weill Cornell Medicine, New York, NY 10065
| | - Chiara Mancinelli
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medicine, New York, NY 10065
| | - Clay Bracken
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - David Eliezer
- Feil Family Brain and Mind Research Institute, Department of Biochemistry and Program in Structural Biology, Weill Cornell Medicine, New York, NY 10065.
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5
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Wang K, Zhang W. Mitochondria-associated endoplasmic reticulum membranes: At the crossroad between familiar and sporadic Alzheimer's disease. Synapse 2021; 75:e22196. [PMID: 33559220 DOI: 10.1002/syn.22196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia and is incurable. The widely accepted amyloid hypothesis failed to produce efficient clinical therapies. In contrast, there is increasing evidence suggesting that the disruption of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) is a critical upstream event of AD pathogenesis. Here, we review MAM's role in some AD symptoms such as plaque formation, tau hyperphosphorylation, synaptic loss, aberrant lipid synthesis, disturbed calcium homeostasis, and abnormal autophagy. At last, we proposed that MAM plays a central role in familial AD (FAD) and sporadic AD (SAD).
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Affiliation(s)
- Kangrun Wang
- Xiangya Hospital, Central South University, Changsha, P.R. China
| | - Wenling Zhang
- The Third Xiangya Hospital, Central South University, Changsha, P.R. China
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6
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Nguyen PH, Ramamoorthy A, Sahoo BR, Zheng J, Faller P, Straub JE, Dominguez L, Shea JE, Dokholyan NV, De Simone A, Ma B, Nussinov R, Najafi S, Ngo ST, Loquet A, Chiricotto M, Ganguly P, McCarty J, Li MS, Hall C, Wang Y, Miller Y, Melchionna S, Habenstein B, Timr S, Chen J, Hnath B, Strodel B, Kayed R, Lesné S, Wei G, Sterpone F, Doig AJ, Derreumaux P. Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis. Chem Rev 2021; 121:2545-2647. [PMID: 33543942 PMCID: PMC8836097 DOI: 10.1021/acs.chemrev.0c01122] [Citation(s) in RCA: 378] [Impact Index Per Article: 126.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Nikolay V Dokholyan
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
- Department of Chemistry, and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
- Molecular Biology, University of Naples Federico II, Naples 80138, Italy
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Saeed Najafi
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics & Faculty of Applied Sciences, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Mara Chiricotto
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - James McCarty
- Chemistry Department, Western Washington University, Bellingham, Washington 98225, United States
| | - Mai Suan Li
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Carol Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yifat Miller
- Department of Chemistry and The Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | | | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Stepan Timr
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Jiaxing Chen
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Brianna Hnath
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, and Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sylvain Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science, Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, China
| | - Fabio Sterpone
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Philippe Derreumaux
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
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7
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Brandt R, Trushina NI, Bakota L. Much More Than a Cytoskeletal Protein: Physiological and Pathological Functions of the Non-microtubule Binding Region of Tau. Front Neurol 2020; 11:590059. [PMID: 33193056 PMCID: PMC7604284 DOI: 10.3389/fneur.2020.590059] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/16/2020] [Indexed: 12/21/2022] Open
Abstract
Tau protein (MAPT) is classified as a microtubule-associated protein (MAP) and is believed to regulate the axonal microtubule arrangement. It belongs to the tau/MAP2/MAP4 family of MAPs that have a similar microtubule binding region at their carboxy-terminal half. In tauopathies, such as Alzheimer's disease, tau is distributed more in the somatodendritic compartment, where it aggregates into filamentous structures, the formation of which correlates with cognitive impairments in patients. While microtubules are the dominant interaction partners of tau under physiological conditions, tau has many additional interaction partners that can contribute to its physiological and pathological role. In particular, the amino-terminal non-microtubule binding domain (N-terminal projection region, NTR) of tau interacts with many partners that are involved in membrane organization. The NTR contains intrinsically disordered regions (IDRs) that show a strong evolutionary increase in the disorder and may have been the basis for the development of new, tau-specific interactions. In this review we discuss the functional organization of the tau protein and the special features of the tau non-microtubule binding region also in the connection with the results of Tau KO models. We consider possible physiological and pathological functions of tau's non-microtubule interactions, which could indicate that interactions mediated by tau's NTR and regulated by far-reaching functional interactions of the PRR and the extreme C-terminus of tau contribute to the pathological processes.
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Affiliation(s)
- Roland Brandt
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany.,Center for Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany.,Institute of Cognitive Science, University of Osnabrück, Osnabrück, Germany
| | | | - Lidia Bakota
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
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8
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Das T, Acosta D, Eliezer D. Interactions of IDPs with Membranes Using Dark-State Exchange NMR Spectroscopy. Methods Mol Biol 2020; 2141:585-608. [PMID: 32696379 PMCID: PMC8185907 DOI: 10.1007/978-1-0716-0524-0_30] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Membrane interactions of proteins play a role in essential cellular processes in both physiological and disease states. The structural flexibility of intrinsically disordered proteins (IDPs) allows for interactions with multiple partners, including membranes. However, determining conformational states of IDPs when interacting with membranes can be challenging. Here we describe the use of nuclear magnetic resonance (NMR), including dark-state exchange saturation transfer (DEST), to probe IDP-membrane interactions in order to determine whether there is an interaction, which residues participate, and the extent/nature of the interaction between the protein and the membrane. Using α-synuclein and tau as typical examples, we provide protocols for how the membrane interactions of IDPs can be probed, including details of how the samples should be prepared and guidelines on how to interpret the results.
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Affiliation(s)
- Tapojyoti Das
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA
- Brain and Mind Research Institute,, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Diana Acosta
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA
- Brain and Mind Research Institute,, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA.
- Brain and Mind Research Institute,, Weill Cornell Medical College of Cornell University, New York, NY, USA.
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9
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Acosta D, Das T, Eliezer D. Probing IDP Interactions with Membranes by Fluorescence Spectroscopy. Methods Mol Biol 2020; 2141:555-567. [PMID: 32696377 DOI: 10.1007/978-1-0716-0524-0_28] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The microtubule-associated protein tau has been extensively studied as a culprit in Alzheimer's disease and other neurodegenerative diseases known as tauopathies. Challenges in structurally defining tau protein emerge from its disordered nature, which makes it difficult to crystallize, and hinder efforts to interpret tau protein's true function. The complexity of intrinsically disordered proteins (IDPs) necessitates a multifaceted approach to study their interactions including multiple spectroscopic methods that can report on local protein environment and structure at individual residue positions. We and others have shown that in addition to binding to microtubules, tau binds to lipid membranes. Tau-membrane interactions may be relevant both to normal tau function and to tau aggregation and pathology. Here we describe the use of fluorescence spectroscopy as a probe of protein-membrane interactions to determine whether there is an interaction, which residues participate, and the extent/nature of the interface between the protein and the membrane. We provide a protocol for how the membrane interactions of tau protein, as an example, can be probed by fluorescence spectroscopy, including details of how the samples should be prepared and guidelines on how to interpret the results.
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Affiliation(s)
- Diana Acosta
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA.,Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Tapojyoti Das
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA.,Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medical College of Cornell University, New York, NY, USA. .,Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA.
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10
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Ojo JO, Algamal M, Leary P, Abdullah L, Mouzon B, Evans JE, Mullan M, Crawford F. Disruption in Brain Phospholipid Content in a Humanized Tau Transgenic Model Following Repetitive Mild Traumatic Brain Injury. Front Neurosci 2018; 12:893. [PMID: 30564087 PMCID: PMC6288299 DOI: 10.3389/fnins.2018.00893] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
Repetitive mild traumatic brain injury (mTBI) is a risk factor for the development of neurodegenerative diseases such as chronic traumatic encephalopathy typified by immunoreactive tau aggregates in the depths of the sulci. However, the underlying neurobiological mechanisms involved have not been largely explored. Phospholipids are important molecules which form membrane lipid bilayers; they are ubiquitous to every cell in the brain, and carry out a host of different functions. Imbalance in phospholipid metabolism, signaling and transport has been documented in some neurological conditions. However, not much is currently known about their roles in repetitive mTBI and how this may confer risk for the development of age-related neurodegenerative diseases. To address this question, we designed a longitudinal study (24 h, 3, 6, 9, and 12 months post-injury) to comprehensively investigate mTBI dependent brain phospholipid profiles compared to sham counterparts. We use our established mouse model of repetitive mTBI that has been extensively characterized up to 1-year post-injury in humanized tau (hTau) mice, which expresses all six human tau isoforms, on a null murine background. Our data indicates a significant increase in sphingomyelin, phosphatidylethanolamine (PE), phosphatidylcholine (PC), and derivative lysoPE and lysoPC at acute and/or sub-acute time points post-injury within the cortex and hippocampus. There was also a parallel increase at early time points in monounsaturated, polyunsaturated and saturated fatty acids. Omega-6 (arachidonic acid) to omega-3 (docosahexaenoic acid) fatty acid ratio for PE and PC species was increased also at 24 h and 3 months post-injury in both hippocampus and cortex. The long-term consequences of these early changes in phospholipids on neuronal and non-neuronal cell function is unclear, and warrants further study. Understanding phospholipid metabolism, signaling and transport following TBI could be valuable; they may offer novel targets for therapeutic intervention not only in TBI but other neurodegenerative diseases.
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Affiliation(s)
- Joseph O. Ojo
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- James A. Haley Veterans’ Hospital, Tampa, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Moustafa Algamal
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Paige Leary
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
| | - Laila Abdullah
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- James A. Haley Veterans’ Hospital, Tampa, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Benoit Mouzon
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - James E. Evans
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
| | - Michael Mullan
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Fiona Crawford
- Experimental Neuropathology and Omics Laboratory, Roskamp Institute, Sarasota, FL, United States
- James A. Haley Veterans’ Hospital, Tampa, FL, United States
- The School of Life, Health and Chemical Sciences, Open University, Milton Keynes, United Kingdom
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11
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Press-Sandler O, Miller Y. Molecular mechanisms of membrane-associated amyloid aggregation: Computational perspective and challenges. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1889-1905. [DOI: 10.1016/j.bbamem.2018.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 01/02/2023]
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12
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Discovery and characterization of stable and toxic Tau/phospholipid oligomeric complexes. Nat Commun 2017; 8:1678. [PMID: 29162800 PMCID: PMC5698329 DOI: 10.1038/s41467-017-01575-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 09/29/2017] [Indexed: 11/13/2022] Open
Abstract
The microtubule-associated protein Tau plays a central role in the pathogenesis of Alzheimer’s disease. Although Tau interaction with membranes is thought to affect some of its physiological functions and its aggregation properties, the sequence determinants and the structural and functional consequences of such interactions remain poorly understood. Here, we report that the interaction of Tau with vesicles results in the formation of highly stable protein/phospholipid complexes. These complexes are toxic to primary hippocampal cultures and are detected by MC-1, an antibody recognizing pathological Tau conformations. The core of these complexes is comprised of the PHF6* and PHF6 hexapeptide motifs, the latter in a β-strand conformation. Studies using Tau-derived peptides enabled the design of mutants that disrupt Tau interactions with phospholipids without interfering with its ability to form fibrils, thus providing powerful tools for uncoupling these processes and investigating the role of membrane interactions in regulating Tau function, aggregation and toxicity. The Alzheimer protein Tau interacts with biological membranes, but the role of these interactions in regulating Tau function in health and disease remains unexplored. Here, the authors report on the discovery and characterization of neurotoxic oligomeric protein/phospholipid complexes.
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13
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Guo T, Noble W, Hanger DP. Roles of tau protein in health and disease. Acta Neuropathol 2017; 133:665-704. [PMID: 28386764 PMCID: PMC5390006 DOI: 10.1007/s00401-017-1707-9] [Citation(s) in RCA: 562] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/26/2017] [Accepted: 03/26/2017] [Indexed: 01/18/2023]
Abstract
Tau is well established as a microtubule-associated protein in neurons. However, under pathological conditions, aberrant assembly of tau into insoluble aggregates is accompanied by synaptic dysfunction and neural cell death in a range of neurodegenerative disorders, collectively referred to as tauopathies. Recent advances in our understanding of the multiple functions and different locations of tau inside and outside neurons have revealed novel insights into its importance in a diverse range of molecular pathways including cell signalling, synaptic plasticity, and regulation of genomic stability. The present review describes the physiological and pathophysiological properties of tau and how these relate to its distribution and functions in neurons. We highlight the post-translational modifications of tau, which are pivotal in defining and modulating tau localisation and its roles in health and disease. We include discussion of other pathologically relevant changes in tau, including mutation and aggregation, and how these aspects impinge on the propensity of tau to propagate, and potentially drive neuronal loss, in diseased brain. Finally, we describe the cascade of pathological events that may be driven by tau dysfunction, including impaired axonal transport, alterations in synapse and mitochondrial function, activation of the unfolded protein response and defective protein degradation. It is important to fully understand the range of neuronal functions attributed to tau, since this will provide vital information on its involvement in the development and pathogenesis of disease. Such knowledge will enable determination of which critical molecular pathways should be targeted by potential therapeutic agents developed for the treatment of tauopathies.
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Affiliation(s)
- Tong Guo
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK
| | - Wendy Noble
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK
| | - Diane P Hanger
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK.
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14
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Villamil-Ortiz JG, Barrera-Ocampo A, Piedrahita D, Velásquez-Rodríguez CM, Arias-Londoño JD, Cardona-Gómez GP. BACE1 RNAi Restores the Composition of Phosphatidylethanolamine-Derivates Related to Memory Improvement in Aged 3xTg-AD Mice. Front Cell Neurosci 2016; 10:260. [PMID: 27891075 PMCID: PMC5105502 DOI: 10.3389/fncel.2016.00260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/26/2016] [Indexed: 01/16/2023] Open
Abstract
β-amyloid (Aβ) is produced by the β-secretase 1 (BACE1)-mediated enzymatic cleavage of the amyloid precursor protein through the amyloidogenic pathway, making BACE1 a therapeutic target against Alzheimer’s disease (AD). Alterations in lipid metabolism are a risk factor for AD by an unknown mechanism. The objective of this study was to determine the effect of RNA interference against BACE1 (shBACEmiR) on the phospholipid profile in hippocampal CA1 area in aged 3xTg-AD mice after 6 and 12 months of treatment compared to aged PS1KI mice. The shBACEmiR treatment induced cognitive function recovery and restored mainly the fatty acid composition of lysophosphatidylethanolamine and etherphosphatidylethanolamine, reduced the cPLA2’s phosphorylation, down-regulated the levels of arachidonic acid and COX2 in the hippocampi of 3xTg-AD mice. Together, our findings suggest, for the first time, that BACE1 silencing restores phospholipids composition which could favor the recovery of cellular homeostasis and cognitive function in the hippocampus of triple transgenic AD mice.
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Affiliation(s)
- Javier G Villamil-Ortiz
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | - Alvaro Barrera-Ocampo
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | - Diego Piedrahita
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
| | | | | | - Gloria P Cardona-Gómez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Sede de Investigación Universitaria, University of Antioquia Medellín, Colombia
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15
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Georgieva ER, Xiao S, Borbat PP, Freed JH, Eliezer D. Tau binds to lipid membrane surfaces via short amphipathic helices located in its microtubule-binding repeats. Biophys J 2015; 107:1441-52. [PMID: 25229151 DOI: 10.1016/j.bpj.2014.07.046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/18/2014] [Accepted: 07/24/2014] [Indexed: 11/16/2022] Open
Abstract
Tau is a microtubule-associated protein that is genetically linked to dementia and linked to Alzheimer's disease via its presence in intraneuronal neurofibrillary tangle deposits, where it takes the form of aggregated paired helical and straight filaments. Although the precise mechanisms by which tau contributes to neurodegeneration remain unclear, tau aggregation is commonly considered to be a critical component of tau-mediated pathogenicity. Nevertheless, the context in which tau aggregation begins in vivo is unknown. Tau is enriched in membrane-rich neuronal structures such as axons and growth cones, and can interact with membranes both via intermediary proteins and directly via its microtubule-binding domain (MBD). Membranes efficiently facilitate tau aggregation in vitro, and may therefore provide a physiologically relevant context for nucleating tau aggregation in vivo. Furthermore, tau-membrane interactions may potentially play a role in tau's poorly understood normal physiological functions. Despite the potential importance of direct tau-membrane interactions for tau pathology and physiology, the structural mechanisms that underlie such interactions remain to be elucidated. Here, we employ electron spin resonance spectroscopy to investigate the secondary and long-range structural properties of the MBD of three-repeat tau isoforms when bound to lipid vesicles and membrane mimetics. We show that the membrane interactions of the tau MBD are mediated by short amphipathic helices formed within each of the MBD repeats in the membrane-bound state. To our knowledge, this is the first detailed elucidation of helical tau structure in the context of intact lipid bilayers. We further show, for the first time (to our knowledge), that these individual helical regions behave as independent membrane-binding sites linked by flexible connecting regions. These results represent the first (to our knowledge) detailed structural view of membrane-bound tau and provide insights into potential mechanisms for membrane-mediated tau aggregation. Furthermore, the results may have implications for the structural basis of tau-microtubule interactions and microtubule-mediated tau aggregation.
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Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York
| | - Shifeng Xiao
- Department of Biochemistry, Weill Cornell Medical College, New York, New York; Program in Structural Biology, Weill Cornell Medical College, New York, New York
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York.
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medical College, New York, New York; Program in Structural Biology, Weill Cornell Medical College, New York, New York.
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16
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Kim HY, Huang BX, Spector AA. Phosphatidylserine in the brain: metabolism and function. Prog Lipid Res 2014; 56:1-18. [PMID: 24992464 DOI: 10.1016/j.plipres.2014.06.002] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/18/2014] [Accepted: 06/21/2014] [Indexed: 01/08/2023]
Abstract
Phosphatidylserine (PS) is the major anionic phospholipid class particularly enriched in the inner leaflet of the plasma membrane in neural tissues. PS is synthesized from phosphatidylcholine or phosphatidylethanolamine by exchanging the base head group with serine, and this reaction is catalyzed by phosphatidylserine synthase 1 and phosphatidylserine synthase 2 located in the endoplasmic reticulum. Activation of Akt, Raf-1 and protein kinase C signaling, which supports neuronal survival and differentiation, requires interaction of these proteins with PS localized in the cytoplasmic leaflet of the plasma membrane. Furthermore, neurotransmitter release by exocytosis and a number of synaptic receptors and proteins are modulated by PS present in the neuronal membranes. Brain is highly enriched with docosahexaenoic acid (DHA), and brain PS has a high DHA content. By promoting PS synthesis, DHA can uniquely expand the PS pool in neuronal membranes and thereby influence PS-dependent signaling and protein function. Ethanol decreases DHA-promoted PS synthesis and accumulation in neurons, which may contribute to the deleterious effects of ethanol intake. Improvement of some memory functions has been observed in cognitively impaired subjects as a result of PS supplementation, but the mechanism is unclear.
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Affiliation(s)
- Hee-Yong Kim
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9410, United States.
| | - Bill X Huang
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9410, United States
| | - Arthur A Spector
- Laboratory of Molecular Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9410, United States
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17
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Barré P, Eliezer D. Structural transitions in tau k18 on micelle binding suggest a hierarchy in the efficacy of individual microtubule-binding repeats in filament nucleation. Protein Sci 2013; 22:1037-48. [PMID: 23740819 DOI: 10.1002/pro.2290] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 12/31/2022]
Abstract
The protein tau is found in an aggregated filamentous state in the intraneuronal paired helical filament deposits characteristic of Alzheimer's disease and other related dementias and mutations in tau protein and mRNA cause frontotemproal dementia. Tau isoforms include a microtubule-binding domain containing either three or four imperfect tandem microtubule binding repeats that also form the core of tau filaments and contain hexapaptide motifs that are critical for tau aggregation. The tau microtubule-binding domain can also engage in direct interactions with detergents, fatty acids, or membranes, which can greatly facilitate tau aggregation and may also mediate some tau functions. Here, we show that the alternatively spliced second microtubule-binding repeat exhibits significantly different structural characteristics compared with the other three repeats in the context of the intact repeat domain. Most notably, the PHF6* hexapeptide motif located at the N-terminus of repeat 2 has a lower propensity to form strand-like structure than the corresponding PHF6 motif in repeat 3, and unlike PHF6 converts to partially helical structure in the micelle-bound state. Interestingly, the behavior of the Module-B motif, located at the beginning of repeat 4, resembles that of PHF6* rather than PHF6. Our observations, combined with previous results showing that PHF6* and Module-B are both less effective than PHF6 in nucleating tau aggregation, suggest a hierarchy in the efficacy of these motifs in nucleating tau aggregation that originates in differences in their intrinsic propensities for extended strand-like structure and the resistance of these propensities to changes in tau's environment.
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Affiliation(s)
- Patrick Barré
- Department of Biochemistry, Program in Structural Biology, Weill Cornell Medical College, New York, 10065, USA
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18
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Boggs JM, Rangaraj G, Heng YM, Liu Y, Harauz G. Myelin basic protein binds microtubules to a membrane surface and to actin filaments in vitro: effect of phosphorylation and deimination. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:761-73. [PMID: 21185260 DOI: 10.1016/j.bbamem.2010.12.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 12/16/2022]
Abstract
Myelin basic protein (MBP) is a multifunctional protein involved in maintaining the stability and integrity of the myelin sheath by a variety of interactions with membranes and other proteins. It assembles actin filaments and microtubules, can bind actin filaments and SH3-domains to a membrane surface, and may be able to tether them to the oligodendrocyte membrane and participate in signal transduction in oligodendrocytes/myelin. In the present study, we have shown that the 18.5 kDa MBP isoform can also bind microtubules to lipid vesicles in vitro. Phosphorylation of MBP at Thr94 and Thr97 (bovine sequence) by MAPK, and deimination of MBP (using a pseudo-deiminated recombinant form), had little detectable effect on its ability to polymerize and bundle microtubules, in contrast to the effect of these modifications on MBP-mediated assembly of actin. However, these modifications dramatically decreased the ability of MBP to tether microtubules to lipid vesicles. MBP and its phosphorylated and pseudo-deiminated variants were also able to bind microtubules to actin filaments. These results suggest that MBP may be able to tether microtubules to the cytoplasmic surface of the oligodendrocyte membrane, and that this binding can be regulated by post-translational modifications to MBP. We further show that MBP appears to be co-localized with actin filaments and microtubules in cultured oligodendrocytes, and also at the interface between actin filaments at the leading edge of membrane processes and microtubules behind them. Thus, MBP may also cross-link microtubules to actin filaments in vivo.
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Affiliation(s)
- Joan M Boggs
- Molecular Structure and Function Program, Research Institute, the Hospital for Sick Children, Toronto, ON, Canada.
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19
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Rojo L, Sjöberg MK, Hernández P, Zambrano C, Maccioni RB. Roles of cholesterol and lipids in the etiopathogenesis of Alzheimer's disease. J Biomed Biotechnol 2010; 2006:73976. [PMID: 17047312 PMCID: PMC1559932 DOI: 10.1155/jbb/2006/73976] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Alzheimer's disease is the principal cause of dementia throughout the world and the fourth cause of death in developed economies.This brain disorder is characterized by the formation of brain protein aggregates, namely, the paired helical filaments and senile plaques. Oxidative stress during life, neuroinflamamtion, and alterations in neuron-glia interaction patterns have been also involved in the etiopathogenesis of this disease. In recent years, cumulative evidence has been gained on the involvement of alteration in neuronal lipoproteins activity, as well as on the role of cholesterol and other lipids in the pathogenesis of this neurodegenerative disorder. In this review, we analyze the links between changes in cholesterol homeostasis, and the changes of lipids of major importance for neuronal activity and Alheimer's disease. The investigation on the fine molecular mechanisms underlying the lipids influence in the etiopathogenesis of Alzheimer's disease may shed light into its treatment and medical management.
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Affiliation(s)
- Leonel Rojo
- Laboratory of Cellular and Molecular Biology and Neurosciences, Millennium Institute for Advanced Studies in
Cell Biology and Biotechnology (CBB), Millennium Building, Las Encinas 3370, Ñuñoa, Santiago, Chile
- Department of Chemistry, Arturo Prat University, avenue Arturo Prat 2120, Iquique, Chile
| | - Marcela K. Sjöberg
- Laboratory of Cellular and Molecular Biology and Neurosciences, Millennium Institute for Advanced Studies in
Cell Biology and Biotechnology (CBB), Millennium Building, Las Encinas 3370, Ñuñoa, Santiago, Chile
- Department of Neurological Sciences, Faculty of Medicine, University of Chile, Salvador 486, 750-0922 Providencia,
Santiago, Chile
| | - Paula Hernández
- Laboratory of Cellular and Molecular Biology and Neurosciences, Millennium Institute for Advanced Studies in
Cell Biology and Biotechnology (CBB), Millennium Building, Las Encinas 3370, Ñuñoa, Santiago, Chile
- Department of Neurological Sciences, Faculty of Medicine, University of Chile, Salvador 486, 750-0922 Providencia,
Santiago, Chile
| | - Cristian Zambrano
- Laboratory of Cellular and Molecular Biology and Neurosciences, Millennium Institute for Advanced Studies in
Cell Biology and Biotechnology (CBB), Millennium Building, Las Encinas 3370, Ñuñoa, Santiago, Chile
- Department of Neurological Sciences, Faculty of Medicine, University of Chile, Salvador 486, 750-0922 Providencia,
Santiago, Chile
| | - Ricardo B. Maccioni
- Laboratory of Cellular and Molecular Biology and Neurosciences, Millennium Institute for Advanced Studies in
Cell Biology and Biotechnology (CBB), Millennium Building, Las Encinas 3370, Ñuñoa, Santiago, Chile
- Department of Neurological Sciences, Faculty of Medicine, University of Chile, Salvador 486, 750-0922 Providencia,
Santiago, Chile
- *Ricardo B. Maccioni:
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20
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Elbaum-Garfinkle S, Ramlall T, Rhoades E. The role of the lipid bilayer in tau aggregation. Biophys J 2010; 98:2722-30. [PMID: 20513417 PMCID: PMC2877329 DOI: 10.1016/j.bpj.2010.03.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/12/2010] [Accepted: 03/02/2010] [Indexed: 11/22/2022] Open
Abstract
Tau is a microtubule associated protein whose aggregation is implicated in a number of neurodegenerative diseases. We investigate the mechanism by which anionic lipid vesicles induce aggregation of tau in vitro using K18, a fragment of tau corresponding to the four repeats of the microtubule binding domain. Our results show that aggregation occurs when the amount of K18 bound to the lipid bilayer exceeds a critical surface density. The ratio of protein/lipid at the critical aggregation concentration is pH-dependent, as is the binding affinity. At low pH, where the protein binds with high affinity, the critical surface density is independent both of total lipid concentration as well as the fraction of anionic lipid present in the bilayer. Furthermore, the aggregates consist of both protein and vesicles and bind the beta-sheet specific dye, Thioflavin T, in the manner characteristic of pathological aggregates. Our results suggest that the lipid bilayer facilitates protein-protein interactions both by screening charges on the protein and by increasing the local protein concentration, resulting in rapid aggregation. Because anionic lipids are abundant in cellular membranes, these findings contribute to understanding tau-lipid bilayer interactions that may be relevant to disease pathology.
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Key Words
- al488, alexa fluor 488
- cac, critical aggregation concentration
- fcs, fluorescence correlation spectroscopy
- luvs, large unilamellar vesicles
- nft, neurofibrillary tangle
- pc, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine
- phfs, paired helical filaments
- ps, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine
- tht, thioflavin t
- rhod-pe, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-(lissamine rhodamine b sulfonyl)
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Affiliation(s)
- Shana Elbaum-Garfinkle
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Trudy Ramlall
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York
| | - Elizabeth Rhoades
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
- Department of Physics, Yale University, New Haven, Connecticut
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21
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Wolff J. Plasma membrane tubulin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1415-33. [PMID: 19328773 DOI: 10.1016/j.bbamem.2009.03.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 03/13/2009] [Accepted: 03/19/2009] [Indexed: 01/17/2023]
Abstract
The association of tubulin with the plasma membrane comprises multiple levels of penetration into the bilayer: from integral membrane protein, to attachment via palmitoylation, to surface binding, and to microtubules attached by linker proteins to proteins in the membrane. Here we discuss the soundness and weaknesses of the chemical and biochemical evidence marshaled to support these associations, as well as the mechanisms by which tubulin or microtubules may regulate functions at the plasma membrane.
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Affiliation(s)
- J Wolff
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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22
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Dietary supplementation with a combination of α-lipoic acid, acetyl-l-carnitine, glycerophosphocoline, docosahexaenoic acid, and phosphatidylserine reduces oxidative damage to murine brain and improves cognitive performance. Nutr Res 2009; 29:70-4. [DOI: 10.1016/j.nutres.2008.11.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 11/22/2022]
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23
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Nonaka Y, Miyajima M, Ogino I, Nakajima M, Arai H. Analysis of neuronal cell death in the cerebral cortex of H-Tx rats with compensated hydrocephalus. J Neurosurg Pediatr 2008; 1:68-74. [PMID: 18352806 DOI: 10.3171/ped-08/01/068] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECT Some cases of compensatory hydrocephalus have been reported in which cognitive deficiency progresses despite the absence of progressive ventricular dilation. In this study, the differentially expressed genes in compensated hydrocephalic H-Tx rat cortices were determined. A molecular mechanism that induces neuronal death in the cerebral cortex of compensated hydrocephalus is proposed. METHODS The cerebral cortices of 8-week-old H-Tx rats with spontaneously arrested hydrocephalus (hH-Tx) and nonhydrocephalic H-Tx (nH-Tx) control rats were subjected to cDNA microarray analysis followed by canonical pathway analysis. RESULTS In the hH-Tx rats, many genes in the amyloidal processing pathway showed altered expression, including Akt3 and p38 MAPK. These latter genes are involved in tau protein phosphorylation, and their increased expression in hydrocephalus was confirmed by real-time polymerase chain reaction analysis. Immunohistological and immunoblot analysis revealed elevated phosphorylated tau expression in the cerebral cortex neurons of the hH-Tx rats. CONCLUSIONS The accumulation of phosphorylated tau protein in the cerebral cortex may be one of the mechanisms by which later cognitive dysfunction develops in patients with compensated hydrocephalus. More work needs to be done to determine if the accumulation of phosphorylated tau in the cortex can help predict which patients may decompensate thus requiring more aggressive treatment for compensated hydrocephalus.
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Affiliation(s)
- Yasuomi Nonaka
- Department of Neurosurgery and Research Institute for Diseases of Old Age, Juntendo University School of Medicine, Tokyo, Japan.
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Barré P, Eliezer D. Folding of the repeat domain of tau upon binding to lipid surfaces. J Mol Biol 2006; 362:312-26. [PMID: 16908029 DOI: 10.1016/j.jmb.2006.07.018] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 07/11/2006] [Accepted: 07/11/2006] [Indexed: 10/24/2022]
Abstract
The microtubule-associated protein tau is impacted in neurodegeneration and dementia through its deposition in the form of paired helical filaments in Alzheimer's disease neurofibrillary tangles and through mutations linking it to the autosomal dominant disorder frontotemporal dementia with Parkinsonism. When isolated in solution tau is intrinsically unstructured and does not fold, while the conformation of the protein in the microtubule-bound state remains uncharacterized. Here we show that the repeat region of tau, which has been reported both to mediate tau microtubule interactions and to constitute the proteolysis-resistant core of disease-associated tau aggregates, associates with lipid micelles and vesicles and folds into an ordered structure upon doing so. In addition to providing the first structural insights into a folded state of tau, our results support a role for lipid membranes in mediating tau function and tau pathology.
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Affiliation(s)
- Patrick Barré
- Department of Biochemistry and Program in Structural Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
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25
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Escribá PV. Membrane-lipid therapy: a new approach in molecular medicine. Trends Mol Med 2006; 12:34-43. [PMID: 16325472 DOI: 10.1016/j.molmed.2005.11.004] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 10/27/2005] [Accepted: 11/17/2005] [Indexed: 10/25/2022]
Abstract
Although most drugs bind to proteins and regulate their activity, some drugs act through a new therapeutic approach called membrane-lipid therapy and bind to lipids, thus modulating the structure of membranes. Most cellular functions are highly dependent on the lipid environment because they are controlled by proteins in or around membranes. The wide variety of cell and organelle membranes and the existence of special lipid regions (e.g. microvilli) and domains (e.g. lipid rafts) support the possibility of designing specific lipid therapies. Indeed, recent evidence suggests that lipid therapy might have potential for the treatment of cancer, cardiovascular pathologies, neurodegenerative processes, obesity, metabolic disorders, inflammation, and infectious and autoimmune diseases.
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Affiliation(s)
- Pablo V Escribá
- Molecular and Cellular Biomedicine, Associate Unit of the Consejo Superior de Investigaciones Científicas, IUNICS, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain.
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26
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Moran CM, Donnelly M, Ortiz D, Pant HC, Mandelkow EM, Shea TB. Cdk5 inhibits anterograde axonal transport of neurofilaments but not that of tau by inhibition of mitogen-activated protein kinase activity. ACTA ACUST UNITED AC 2005; 134:338-44. [PMID: 15836929 DOI: 10.1016/j.molbrainres.2004.10.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 10/29/2004] [Accepted: 10/29/2004] [Indexed: 11/19/2022]
Abstract
Cyclin-dependent kinase 5 (cdk5) inhibits neurofilament (NF) anterograde axonal transport while p42/44 mitogen-activated protein kinase (MAPk) promotes it. Since cdk5 is known to inhibit MAP kinase activity, we examined whether or not cdk5 inhibits anterograde NF transport via inhibition of MAPk activity. To accomplish this, we manipulated the activity of these kinases in differentiated NB2a/d1 cells, and monitored anterograde axonal transport of green fluorescent protein-conjugated-NF-M (GFP-M) and cyan fluorescent protein-conjugated (CFP)-tau. The cdk5 inhibitor roscovitine increased anterograde axonal transport of GFP-M and CFP-tau; transfection with cdk5/p25 inhibited transport of both. Inhibition of MAPk activity by PD98059 or expression of dominant-negative MAPk inhibited anterograde GFP-M transport, while expression of constitutively active MAPk enhanced it; these treatments did not affect CFP-tau transport. PD98059 prevented roscovitine-mediated enhancement of GFP-M transport, but did not prevent enhancement of CFP-tau transport. Co-transfection with constitutively activated MAPk prevented the inhibition of GFP-M transport that normally accompanied transfection with cdk5/p25, but did not prevent inhibition of tau transport by cdk5/p25. Finally, the extent of inhibition of GFP-M axonal transport by PD98059 was not additive to that derived from transfection with cdk5/p35, and the increase in NF transport that accompanies roscovitine treatment was not additive to that derived from transfection with constitutively activated MAPk, suggesting that the influence of these kinases on NF transport was within the same, rather than distinct, pathways. These findings suggest that axonal transport of tau and NFs is under the control of distinct kinase cascades, and that cdk5 inhibits NF transport at least in part by inhibiting MAPk.
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Affiliation(s)
- Catherine M Moran
- Center for Cell Neurobiology and Neurodegeneration Research, University of Massachusetts Lowell, Lowell, MA 01854, USA
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27
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Chan WKH, Dickerson A, Ortiz D, Pimenta AF, Moran CM, Motil J, Snyder SJ, Malik K, Pant HC, Shea TB. Mitogen-activated protein kinase regulates neurofilament axonal transport. J Cell Sci 2004; 117:4629-42. [PMID: 15331628 DOI: 10.1242/jcs.01135] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mitogen-activated protein kinase (MAP) kinase plays a pivotal role in the development of the nervous system by mediating both neurogenesis and neuronal differentiation. Here we examined whether p42/44 MAP kinase plays a role in axonal transport and the organization of neurofilaments (NFs) in axonal neurites. Dominant-negative p42/44 MAP kinase, anti-MAP kinase antisense oligonucleotides and the MAP kinase inhibitor PD98059 all reduced NF phospho-epitopes and inhibited anterograde NF axonal transport of GFP-tagged NF subunits in differentiated NB2a/d1 neuroblastoma cells. Expression of constitutively active MAP kinase and intracellular delivery of active enzyme increased NF phospho-epitopes and increased NF axonal transport. Longer treatment with PD98059 shifted NF transport from anterograde to retrograde. PD98059 did not inhibit overall axonal transport nor compromise overall axonal architecture or composition. The p38 MAP kinase inhibitor SB202190 did not inhibit NF transport whereas the kinase inhibitor olomoucine inhibited both NF and mitochondrial transport. Axonal transport of NFs containing NF-H whose C-terminal region was mutated to mimic extensive phosphorylation was substantially less affected by PD98059 compared to a wild-type construct. These data suggest that p42/44 MAP kinase regulates NF anterograde transport by NF C-terminal phosphorylation. MAP kinase may therefore stabilize developing axons by promoting the accumulation of NFs within growing axonal neurites.
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Affiliation(s)
- Walter Kong-Ho Chan
- Center Cell Neurobiology and Neurodegeneration Research, University of Massachusetts, Lowell, MA 01854, USA
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28
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Schaecher K, Goust JM, Banik NL. The effects of calpain inhibition on IkB alpha degradation after activation of PBMCs: identification of the calpain cleavage sites. Neurochem Res 2004; 29:1443-51. [PMID: 15202778 DOI: 10.1023/b:nere.0000026410.56000.dd] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Human peripheral blood mononuclear cells (PBMCs) were activated using anti-CD3/CD28 (HIT3A/CD28.2) resulting in degradation of IkB alpha, an inhibitor of NFkB, relative to unactivated cells. Degradation of IkB alpha began by 30 min and proceeded for at least 5 h. Calpeptin, a calpain inhibitor, inhibited IkB alpha degradation in a time- and dose-dependent manner. Furthermore, calpain inhibition increased IkB alpha levels compared to nonactivated controls. Recombinant IkB alpha was incubated with purified porcine m-calpain in the presence of 0.1% Triton X-100, and the degradation products were monitored by SDS-PAGE and sequenced. Most of the degradation products were peptides derived from calpain, but one was derived from IkB alpha cleaved between amino acids 50 and 51 (glutamine and glutamic acid). The liberated fragment included the entire signal response domain (SRD), a region containing key serine and threonine residues necessary for phosphorylation by the IKKinase complex and sites required for ubiquitination. The results suggest that calpain plays an important role in IkB alpha degradation, a crucial event in T cell activation.
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Affiliation(s)
- Kurt Schaecher
- Department of Neurology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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29
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Dhitavat S, Ortiz D, Shea TB, Rivera ER. Acetyl-L-carnitine protects against amyloid-beta neurotoxicity: roles of oxidative buffering and ATP levels. Neurochem Res 2002; 27:501-5. [PMID: 12199155 DOI: 10.1023/a:1019800703683] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Acetyl-L-carnitine (ALCAR), normally produced in mitochondria, is a precursor of acetyl-CoA in the tricarboxylic (TCA) cycle. Since mitochondrial compromise and ATP depletion have been considered to play a role in neuronal degeneration in Alzheimer's disease (AD), we examined whether ALCAR attenuated oxidative stress and/or ATP depletion after exposure of cells to beta-amyloid (Abeta), a neurotoxic peptide that accumulates in AD brain. Differentiated SH-SY-5Y human neuroblastoma cells were exposed for 2-24 h to 20 microM Abeta in the presence and absence of 50 microM ALCAR. ALCAR attenuated oxidative stress and cell death induced by Abeta neurotoxicity. Abeta depleted ATP levels, suggesting Abeta may induce neurotoxicity in part by compromising neuronal energy. ALCAR prevented ATP depletion; therefore, ALCAR may mediate its protective effect by buffering oxidative stress and maintaining ATP levels.
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Affiliation(s)
- Sirakarnt Dhitavat
- Center for Neurobiology and Neurodegeneration Research, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA.
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30
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An XL, Takakuwa Y, Manno S, Han BG, Gascard P, Mohandas N. Structural and functional characterization of protein 4.1R-phosphatidylserine interaction: potential role in 4.1R sorting within cells. J Biol Chem 2001; 276:35778-85. [PMID: 11423550 DOI: 10.1074/jbc.m101364200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Erythrocyte protein 4.1R is a multifunctional protein that binds to various membrane proteins and to phosphatidylserine. In the present study, we report two important observations concerning 4.1R-phosphatidylserine interaction. Biochemically, a major finding of the present study is that 4.1R binding to phosphatidylserine appears to be a two-step process in which 4.1R first interacts with serine head group of phosphatidylserine through the positively charged amino acids YKRS and subsequently forms a tight hydrophobic interaction with fatty acid moieties. 4.1R failed to dissociate from phosphatidylserine liposomes under high ionic strength but could be released specifically by phospholipase A(2) but not by phospholipase C or D. Biochemical analyses showed that acyl chains were associated with 4.1R released by phospholipase A(2). Importantly, the association of acyl chains with 4.1R impaired its ability to interact with calmodulin, band 3, and glycophorin C. Removal of acyl chains restored 4.1R binding. These data indicate that acyl chains of phosphatidylserine play an important role in its interaction with 4.1R and on 4.1R function. In terms of biological significance, we have obtained evidence that 4.1R-phosphatidylserine interaction may play an important role in cellular sorting of 4.1R.
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Affiliation(s)
- X L An
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan
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31
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Vanderklish PW, Bahr BA. The pathogenic activation of calpain: a marker and mediator of cellular toxicity and disease states. Int J Exp Pathol 2000; 81:323-39. [PMID: 11168679 PMCID: PMC2517738 DOI: 10.1111/j.1365-2613.2000.00169.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2000] [Accepted: 08/14/2000] [Indexed: 11/30/2022] Open
Abstract
Over-activation of calpain, a ubiquitous calcium-sensitive protease, has been linked to a variety of degenerative conditions in the brain and several other tissues. Dozens of substrates for calpain have been identified and several of these have been used to measure activation of the protease in the context of experimentally induced and naturally occurring pathologies. Calpain-mediated cleavage of the cytoskeletal protein spectrin, in particular, results in a set of large breakdown products (BDPs) that are unique in that they are unusually stable. Over the last 15 years, measurements of BDPs in experimental models of stroke-type excitotoxicity, hypoxia/ischemia, vasospasm, epilepsy, toxin exposure, brain injury, kidney malfunction, and genetic defects, have established that calpain activation is an early and causal event in the degeneration that ensues from acute, definable insults. The BDPs also have been found to increase with normal ageing and in patients with Alzheimer's disease, and the calpain activity may be involved in related apoptotic processes in conjunction with the caspase family of proteases. Thus, it has become increasingly clear that regardless of the mode of disturbance in calcium homeostasis or the cell type involved, calpain is critical to the development of pathology and therefore a distinct and powerful therapeutic target. The recent development of antibodies that recognize the site at which spectrin is cleaved has greatly facilitated the temporal and spatial resolution of calpain activation in situ. Accordingly, sensitive spectrin breakdown assays now are utilized to identify potential toxic side-effects of compounds and to develop calpain inhibitors for a wide range of indications including stroke, cerebral vasospasm, and kidney failure.
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Affiliation(s)
- P W Vanderklish
- Department of Neurobiology, Scripps Research Institute, La Jolla, California, USA
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32
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Tanner SL, Franzen R, Jaffe H, Quarles RH. Evidence for expression of some microtubule-associated protein 1B in neurons as a plasma membrane glycoprotein. J Neurochem 2000; 75:553-62. [PMID: 10899930 DOI: 10.1046/j.1471-4159.2000.0750553.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Microtubule-associated protein (MAP) 1B is a high-molecular-weight cytoskeletal protein that is abundant in developing neuronal processes and appears to be necessary for axonal growth. Various biochemical and immunocytochemical results are reported, indicating that a significant fraction of MAP1B is expressed as an integral membrane glycoprotein in vesicles and the plasma membrane of neurons. MAP1B is present in microsomal fractions isolated from developing rat brain and fractionates across a sucrose gradient in a manner similar to synaptophysin, a well-known vesicular and plasma membrane protein. MAP1B is also in axolemma-enriched fractions (AEFs) isolated from myelinated axons of rat brain. MAP1B in AEFs and membrane fractions from cultured dorsal root ganglion neurons (DRGNs) remains membrane-associated following high-salt washes and contains sialic acid. Furthermore, MAP1B in intact DRGNs is readily degraded by extracellular trypsin and is labeled by the cell surface probe sulfosuccinimidobiotin. Immunocytochemical examination of DRGNs shows that MAP1B is concentrated in vesicle-rich varicosities along the length of axons. Myelinated peripheral nerves immunostained for MAP1B show an enrichment at the axonal plasma membrane. These observations demonstrate that some of the MAP1B in developing neurons is an integral plasma membrane glycoprotein.
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Affiliation(s)
- S L Tanner
- Myelin and Brain Development Section, Laboratory of Molecular and Cellular Neurobiology, National Institutes of Health, Bethesda, Maryland, USA
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33
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Ekinci FJ, Shea TB. Phosphorylation of tau alters its association with the plasma membrane. Cell Mol Neurobiol 2000; 20:497-508. [PMID: 10901269 DOI: 10.1023/a:1007075115574] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. The potential functions of the microtubule-associated protein tau have been expanded by the recent demonstration of its interaction with the plasma membrane. Since the association of tau with microtubules is regulated by phosphorylation, herein we examine whether or not the association of tau with the plasma membrane is also regulated by phosphorylation. 2. A range of tau isoforms migrating from 46 to 64 kDa was associated with crude particulate fractions derived from SH-SY-5Y human neuroblastoma cells, and were retained during the initial stages of plasma membrane purification. During the extensive washing utilized in purification of the plasma membrane, portions of each of these isoforms were depleted from the resultant purified membrane. Immunoblot analysis with phospho-dependent and -independent antibodies revealed selective depletion of phospho isoforms during membrane washing. This effect was more pronounced for the slowest-migrating (64-kDa) tau isoform. 3. This putative influence of phosphorylation on the association of tau with the plasma membrane was further probed by transfection of SH-SY-5Y human neuroblastoma cells with a tau construct that could associate with the plasma membrane but not with microtubules. Treatment with phorbol ester or calcium ionophore, both of which increased phospho-tau levels within the cytosol and plasma membrane, was accompanied by the dissociation of this tau construct from the membrane. 4. These data indicate that phosphorylation regulates the association with the plasma membrane. Dissociation from the membrane by phosphorylation may place tau at risk for hyperphosphorylation and ultimate PHF formation in a manner previously considered for tau dissociated from microtubules.
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Affiliation(s)
- F J Ekinci
- Center for Cellular Neurobiology and Neurodegeneration Research, Department of Biological Sciences, University of Massachusetts at Lowell, 01854, USA
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34
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Abstract
There is mounting evidence that developmental dyslexia is a neurodevelopmental disorder which involves abnormalities of fatty acid metabolism, particularly with respect to certain long-chain highly unsaturated fatty acids (HUFAs). Psychophysical evidence also strongly suggests that dyslexics may have visual deficits as well as phonological problems. Specifically, these visual deficits appear to be related to the magnocellular pathway, which is specialized for processing fast, rapidly-changing information about the visual scene. It remains unclear how these two aspects of dyslexia - fatty acid processing and visual magnocellular function - could be related. We propose some hypotheses - necessarily speculative, given the paucity of biochemical research in this field to date - which address this question.
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Affiliation(s)
- K E Taylor
- University Laboratory of Physiology, Oxford, UK.
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35
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Arrasate M, Pérez M, Avila J. Tau dephosphorylation at tau-1 site correlates with its association to cell membrane. Neurochem Res 2000; 25:43-50. [PMID: 10685603 DOI: 10.1023/a:1007583214722] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been considered that tau protein is mainly a cytoplasmic protein since it is a microtubule associated protein. However, it has also been suggested that tau could be located in the cell nucleus and membrane. In our work, the cellular distribution of tau has been studied by immunofluorescence and western blot analysis, after subcellular fractionation in neuroblastoma cells and in tau-transfected non neural cells using, mainly, two types of tau antibodies; antibody 7.51 (that recognizes tau independent of its phosphorylation level); and antibody Tau-1 (that recognizes tau only in its dephosphorylated form). Also, tau was expressed in COS-1 cells to test for the features involved in the sorting of tau to different cell localizations. Our results show that tau associated to cell membrane has a lower phosphorylation level in its proline-rich region. Additionally, in differentiated neuroblastoma cells, tau phosphorylation, at that region, decreases and the amount of tau associated to cell membrane increases.
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Affiliation(s)
- M Arrasate
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Spain
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36
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Ekinci FJ, Malik KU, Shea TB. Activation of the L voltage-sensitive calcium channel by mitogen-activated protein (MAP) kinase following exposure of neuronal cells to beta-amyloid. MAP kinase mediates beta-amyloid-induced neurodegeneration. J Biol Chem 1999; 274:30322-7. [PMID: 10514528 DOI: 10.1074/jbc.274.42.30322] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal degeneration in Alzheimer's disease (AD) has been variously attributed to increases in cytosolic calcium, reactive oxygen species, and phosphorylated forms of the microtubule-associated protein tau. beta-Amyloid (betaA), which accumulates extracellularly in AD brain, induces calcium influx in culture via the L voltage-sensitive calcium channel. Since this channel is normally activated by protein kinase A-mediated phosphorylation, we examined kinase activities recruited following betaA treatment of cortical neurons and SH-SY-5Y neuroblastoma. betaA increased channel phosphorylation; this increase was unaffected by the protein kinase A inhibitor H89 but was reduced by the mitogen-activated protein (MAP) kinase inhibitor PD98059. Pharmacological and antisense oligonucleotide-mediated reduction of MAP kinase activity also reduced betaA-induced accumulation of calcium, reactive oxygen species, phospho-tau immunoreactivity, and apoptosis. These findings indicate that MAP kinase mediates multiple aspects of betaA-induced neurotoxicity and indicates that calcium influx initiates neurodegeneration in AD. betaA increased MAP kinase-mediated phosphorylation of membrane-associated proteins and reduced phosphorylation of cytosolic proteins without increasing overall MAP kinase activity. Increasing MAP kinase activity with epidermal growth factor did not increase channel phosphorylation. These findings indicate that redirection, rather than increased activation, of MAP kinase activity mediates betaA-induced neurotoxicity.
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Affiliation(s)
- F J Ekinci
- Center for Cellular Neurobiology, Department of Biological Sciences, University of Massachusetts, Lowell, Massachusetts 01854, USA
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37
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Shea TB, Cressman CM. The order of exposure of tau to signal transduction kinases alters the generation of "AD-like" phosphoepitopes. Cell Mol Neurobiol 1999; 19:223-33. [PMID: 10081606 DOI: 10.1023/a:1006977127422] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. The individual and sequential influence of protein kinase C (PKC), protein kinase A (PKA) and mitogen-activated protein kinase (MAP kinase) on human brain tau was examined. 2. A range of PKC concentrations generated certain phosphoepitopes common with paired helical filaments. These epitopes were masked by higher PKC concentrations, suggesting the presence of multiple tau phosphorylation sites for which PKC exhibited differing affinities and/or conformational alterations in tau induced by sequential PKC-mediated phosphorylation. 3. Prior phosphorylation by PKC enhanced the nature and extent of AD-like tau antigenicity generated by subsequent incubation with MAP kinase yet inhibited that generated by subsequent incubation with PKA. 4. Dephosphorylation of tau prior to incubation with kinases significantly altered the influence of individual and multiple kinase incubation on tau antigenicity in a site-specific manner, indicating that prior in situ phosphorylation events markedly influenced subsequent cell-free phosphorylation. 5. In addition to considerations of the potential impact of tau phosphorylation by individual kinases, these findings extend previous studies which indicate that tau antigenicity, and, presumably, its behavior in situ, is influenced by the sequential and convergent influences of multiple kinases.
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Affiliation(s)
- T B Shea
- Department of Biological Sciences, University of Massachusetts at Lowell 01854, USA.
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38
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Ekinci FJ, Shea TB. Hyperactivation of mitogen-activated protein kinase increases phospho-tau immunoreactivity within human neuroblastoma: additive and synergistic influence of alteration of additional kinase activities. Cell Mol Neurobiol 1999; 19:249-60. [PMID: 10081608 DOI: 10.1023/a:1006981228331] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitogen-activated protein (MAP) kinase phosphorylates tau in cell-free analyses, but whether or not it does so within intact cells remains controversial. In the present study, microinjection of MAP kinase into SH-SY-5Y human neuroblastoma cells increased tau immunoreactivity toward the phosphodependent antibodies PHF-1 and AT-8. In contrast, treatment with a specific inhibitor of MAP kinase (PD98059) did not diminish "basal" levels of these immunoreactivities in otherwise untreated cells. These findings indicate that hyperactivation of MAP kinase increases phospho-tau levels within cells, despite that MAP kinase apparently does not substantially influence intracellular tau phosphorylation under normal conditions. These findings underscore that results obtained following inhibition of kinase activities do not necessarily provide an indication of the consequences accompanying hyperactivation of that same kinase. Several studies conducted in cell-free systems indicate that exposure of tau to multiple kinases can have synergistic effects on the nature and extent of tau phosphorylation. We therefore examined whether or not such effects could be demonstrated within these cells. Site-specific phospho-tau immunoreactivity was increased in additive and synergistic manners by treatment of injected cells with TPA (which activates PKC), calcium ionophore (which activates calcium-dependent kinases), and wortmannin (which inhibits PIP3 kinase). Alteration in total tau levels was insufficient to account for the full extent of the increase in phospho-tau immunoreactivity. These additional results indicate that multiple kinase activities modulate the influence of MAP kinase on tau within intact cells.
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Affiliation(s)
- F J Ekinci
- Department of Biological Sciences, University of Massachusetts at Lowell 01854, USA
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39
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Shea TB, Cressman CM. A 26-30 kDa developmentally-regulated tau isoform localized within nuclei of mitotic human neuroblastoma cells. Int J Dev Neurosci 1998; 16:41-8. [PMID: 9664221 DOI: 10.1016/s0736-5748(97)00044-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Tau isoforms migrating at 46-68 and 97-115 kDa were prominent within heat-stable Triton-soluble material, and were present in lesser concentration with Triton-insoluble cytoskeletons, derived from undifferentiated SH-SY-5Y human neuroblastoma cells. Conversely, a 26-30 kDa tau isoform was enriched in the cytoskeleton and detected at relatively minor levels within cytosolic fractions. Pulse labeling with 35S-methionine indicated that this 26-30 kDa "small tau" did not represent a breakdown product of larger isoforms. Since the nucleus is retained within the Triton-insoluble cytoskeleton, additional cultures were fractionated onto sucrose to obtain purified nuclei. The vast majority of small tau was recovered within purified nuclei. Small tau was reactive with tau antibodies directed towards N-terminal, C-terminal and central epitopes, further confirming that this small isoform was not derived from proteolytic cleavage of larger tau isoforms. Small tau demonstrated alkaline phosphatase-sensitive reactivity with multiple phospho-dependent tau antibodies. Small tau was depleted within 3 days of retinoic acid-induced differentiation, suggesting that the putative function of this isoform may be obsolete following terminal differentiation of neurons.
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Affiliation(s)
- T B Shea
- Department of Biological Sciences, University of Massachusetts at Lowell 01854, USA
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