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Hu Z, Chen PH, Li W, Douglas T, Hines J, Liu Y, Crews CM. Targeted Dephosphorylation of Tau by Phosphorylation Targeting Chimeras (PhosTACs) as a Therapeutic Modality. J Am Chem Soc 2023; 145:4045-4055. [PMID: 36753634 DOI: 10.1021/jacs.2c11706] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Microtubule-associated protein tau is essential for microtubule assembly and stabilization. Hyperphosphorylation of the microtubule-associated protein tau plays an important pathological role in the development of Alzheimer's disease and other tauopathies. In vivo studies using kinase inhibitors suggest that reducing tau phosphorylation levels has therapeutic potential; however, such approaches showed limited benefits. We sought to further develop our phosphorylation targeting chimera (PhosTAC) technology to specifically induce tau dephosphorylation. Herein, we use small molecule-based PhosTACs to recruit tau to PP2A, a native tau phosphatase. PhosTACs induced the formation of a stable ternary complex, leading to rapid, efficient, and sustained tau dephosphorylation, which also correlated with the enhanced downregulation of tau protein. Mass spectrometry data validated that PhosTACs downregulated multiple phosphorylation sites of tau. We believe that PhosTAC possesses several advantages over current strategies to modulate tau phosphorylation and represents a new avenue for disease-modifying therapies for tauopathies.
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Affiliation(s)
- Zhenyi Hu
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - Po-Han Chen
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan city 701, Taiwan
| | - Wenxue Li
- Yale Cancer Biology Institute, West Haven, Connecticut 06516, United States
| | - Todd Douglas
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - John Hines
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - Yansheng Liu
- Yale Cancer Biology Institute, West Haven, Connecticut 06516, United States
| | - Craig M Crews
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
- Department of Pharmacology, Yale University, New Haven, Connecticut 06511, United States
- Yale University School of Medicine, New Haven, Connecticut 06511, United States
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2
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Kumar R, Tiwari V, Dey S. Role of proline-rich tyrosine kinase 2 (Pyk2) in the pathogenesis of Alzheimer's disease. Eur J Neurosci 2022; 56:5442-5452. [PMID: 34905657 DOI: 10.1111/ejn.15569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common form of dementia in the elderly. Two major pathological hallmarks have been identified for AD: extracellular amyloid plaques and intracellular neurofibrillary tangles (NFT). Recently, proline-rich tyrosine kinase 2 (Pyk2), which belongs to the focal adhesion kinase (FAK) non-receptor tyrosine kinase family, was recognized to contribute significantly towards the pathogenesis of AD. Pyk2 can influence the formation of amyloid plaques as well as NFTs. The kinase can directly phosphorylate tau, which is a significant component of NFTs and enhances tau pathology. Several competitive inhibitors have been developed for Pyk2, tested in several cancer models, as Pyk2 is known to be overexpressed under those conditions. The current review article discusses the possible mechanistic pathways by which Pyk2 can influence the pathogenesis of AD. Besides, it describes various inhibitors for Pyk2 and their potential role as therapeutics for AD in the future.
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Affiliation(s)
- Rahul Kumar
- Department of Biotechnology, GITAM Institute of Sciences, GITAM University, Visakhapatnam, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Sharmistha Dey
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
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3
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Peng Y, Tao H, Wang S, Xiao J, Wang Y, Su H. Dietary intervention with edible medicinal plants and derived products for prevention of Alzheimer's disease: A compendium of time-tested strategy. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104463] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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4
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Luna-Viramontes NI, Campa-Córdoba BB, Ontiveros-Torres MÁ, Harrington CR, Villanueva-Fierro I, Guadarrama-Ortíz P, Garcés-Ramírez L, de la Cruz F, Hernandes-Alejandro M, Martínez-Robles S, González-Ballesteros E, Pacheco-Herrero M, Luna-Muñoz J. PHF-Core Tau as the Potential Initiating Event for Tau Pathology in Alzheimer's Disease. Front Cell Neurosci 2020; 14:247. [PMID: 33132840 PMCID: PMC7511711 DOI: 10.3389/fncel.2020.00247] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/15/2020] [Indexed: 11/13/2022] Open
Abstract
Worldwide, around 50 million people have dementia. Alzheimer's disease (AD) is the most common type of dementia and one of the major causes of disability and dependency among the elderly worldwide. Clinically, AD is characterized by impaired memory accompanied by other deficiencies in the cognitive domain. Neuritic plaques (NPs) and neurofibrillary tangles (NFTs) are histopathological lesions that define brains with AD. NFTs consist of abundant intracellular paired helical filaments (PHFs) whose main constituent is tau protein. Tau undergoes posttranslational changes including hyperphosphorylation and truncation, both of which favor conformational changes in the protein. The sequential pathological processing of tau is illustrated with the following specific markers: pT231, TG3, AT8, AT100, and Alz50. Two proteolysis sites for tau have been described-truncation at glutamate 391 and at aspartate 421-and which can be demonstrated by reactivity with the antibodies 423 and TauC-3, respectively. In this review, we describe the molecular changes in tau protein as pre-NFTs progress to extracellular NFTs and during which the formation of a minimal nucleus of the filament, as the PHF core, occurs. We also analyzed the PHF core as the initiator of PHFs and tau phosphorylation as a protective neuronal mechanism against the assembly of the PHF core.
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Affiliation(s)
- Nabil Itzi Luna-Viramontes
- National Dementia BioBank, Departamento de Ciencias Biológicas, Facultad de Estudios Superiores, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - B Berenice Campa-Córdoba
- National Dementia BioBank, Departamento de Ciencias Biológicas, Facultad de Estudios Superiores, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Charles R Harrington
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Parménides Guadarrama-Ortíz
- Departamento de Neurocirugía, Centro Especializado en Neurocirugía y Neurociencias México, CENNM, CDMX, Mexico City, Mexico
| | - Linda Garcés-Ramírez
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Fidel de la Cruz
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Mario Hernandes-Alejandro
- Departamento de Bioingeniería, Unidad Profesional Interdisciplinaria de Biotecnología del Instituto Politécnico Nacional (UPIBI-IPN), Mexico City, México
| | - Sandra Martínez-Robles
- National Dementia BioBank, Departamento de Ciencias Biológicas, Facultad de Estudios Superiores, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Erik González-Ballesteros
- National Dementia BioBank, Departamento de Ciencias Biológicas, Facultad de Estudios Superiores, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Mar Pacheco-Herrero
- Neuroscience Research Laboratory, Faculty of Health Sciences, Pontificia Universidad Catolica Madre y Maestra, Santiago de los Caballeros, Dominican Republic
| | - José Luna-Muñoz
- National Dementia BioBank, Departamento de Ciencias Biológicas, Facultad de Estudios Superiores, Universidad Nacional Autónoma de México, Mexico City, Mexico
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5
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Helboe L, Egebjerg J, Barkholt P, Volbracht C. Early depletion of CA1 neurons and late neurodegeneration in a mouse tauopathy model. Brain Res 2017; 1665:22-35. [PMID: 28411086 DOI: 10.1016/j.brainres.2017.04.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/27/2017] [Accepted: 04/05/2017] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) and tauopathies, such as frontotemporal dementia (FTD), are characterized by formation of neurofibrillary tangles consisting of hyperphosphorylated tau. Further neuropathological characteristics include synaptic loss, neurodegeneration and brain atrophy. Here, we explored the association between hyperphosphorylated tau species, brain atrophy, synaptic and neuronal loss in a mouse model (rTg4510) carrying the human tau (hTau) P301L mutation found in a familiar form of FTD. We established that hTau expression during the first 6 postnatal weeks was important for the progression of tauopathy in rTg4510 mice. Short term suppression of postnatal hTau expression delayed the onset of tau pathology by approximately 6months in this model. Early postnatal hTau expression was detrimental to CA1 neurons of the hippocampus and reduced neuronal numbers in 6-10weeks young rTg4510 mice prior to the appearance of hyperphosphorylated hTau species in the hippocampus. Hyperphosphorylated hTau species emerged from 10 to 24weeks of age and were associated with increased ubiquitin levels, gliosis, and brain atrophy and preceded the synaptic loss and CA1 neurodegeneration that occurred at 48weeks of age. We present two consequences of hTau expression in CA1 in rTg4510 mice: an early decrease in neuron number already established prior to the presence of hyperphosphorylated tau species and a later neurodegeneration dependent on hyperphosphorylated tau. Neurodegeneration and synaptic protein loss were completely prevented when hTau expression was suppressed prior to the appearance of hyperphosphorylated tau species. Suppression of hTau expression after the onset of tau hyperphosphorylation and tangle pathology initiated at 16weeks partially rescued neuronal loss at 48weeks of age, while a reduction of neurodegeneration was no longer possible when hTau suppression was introduced as late as at 24weeks of age. Our results in rTg4510 mice argue that it is promising to lower hyperphosphorylated tau species at early stages of tau pathology to protect from neurodegeneration.
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Affiliation(s)
- Lone Helboe
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | - Jan Egebjerg
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | | | - Christiane Volbracht
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark.
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6
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Dagda RK, Das Banerjee T. Role of protein kinase A in regulating mitochondrial function and neuronal development: implications to neurodegenerative diseases. Rev Neurosci 2015; 26:359-70. [PMID: 25741943 DOI: 10.1515/revneuro-2014-0085] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 01/08/2015] [Indexed: 11/15/2022]
Abstract
In neurons, enhanced protein kinase A (PKA) signaling elevates synaptic plasticity, promotes neuronal development, and increases dopamine synthesis. By contrast, a decline in PKA signaling contributes to the etiology of several brain degenerative diseases, including Alzheimer's disease and Parkinson's disease, suggesting that PKA predominantly plays a neuroprotective role. A-kinase anchoring proteins (AKAPs) are large multidomain scaffold proteins that target PKA and other signaling molecules to distinct subcellular sites to strategically localize PKA signaling at dendrites, dendritic spines, cytosol, and axons. PKA can be recruited to the outer mitochondrial membrane by associating with three different AKAPs to regulate mitochondrial dynamics, structure, mitochondrial respiration, trafficking, dendrite morphology, and neuronal survival. In this review, we survey the myriad of essential neuronal functions modulated by PKA but place a special emphasis on mitochondrially localized PKA. Finally, we offer an updated overview of how loss of PKA signaling contributes to the etiology of several brain degenerative diseases.
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Lebel M, Robinson P, Cyr M. Canadian Association of Neurosciences Review: The Role of Dopamine Receptor Function in Neurodegenerative Diseases. Can J Neurol Sci 2014; 34:18-29. [PMID: 17352343 DOI: 10.1017/s0317167100005746] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Dopamine (DA) receptors, which are heavily expressed in the caudate/putamen of the brain, represent the molecular target of several drugs used in the treatment of various neurological disorders, such as Parkinson's disease. Although most of the drugs are very effective in alleviating the symptoms associated with these conditions, their long-term utilization could lead to the development of severe side-effects. In addition to uncovering novel mediators of physiological DA receptor functions, recent research advances are suggesting a role of these receptors in toxic effects on neurons. For instance, accumulating evidence indicates that DA receptors, particularly D1 receptors, are central in the neuronal toxicity induced by elevated synaptic levels of DA. In this review, we will discuss recent findings on DA receptors as regulators of long term neuronal dysfunction and neurodegenerative processes.
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Affiliation(s)
- Manon Lebel
- Neuroscience Research Group, Université du Québec à Trois-Rivières, Canada
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8
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Rijal Upadhaya A, Kosterin I, Kumar S, von Arnim CAF, Yamaguchi H, Fändrich M, Walter J, Thal DR. Biochemical stages of amyloid-β peptide aggregation and accumulation in the human brain and their association with symptomatic and pathologically preclinical Alzheimer’s disease. Brain 2014; 137:887-903. [PMID: 24519982 DOI: 10.1093/brain/awt362] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Ajeet Rijal Upadhaya
- 1 Laboratory of Neuropathology, Institute of Pathology, Centre for Clinical Research at the University of Ulm, Ulm, Germany
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Noble W, Hanger DP, Miller CCJ, Lovestone S. The importance of tau phosphorylation for neurodegenerative diseases. Front Neurol 2013; 4:83. [PMID: 23847585 PMCID: PMC3696910 DOI: 10.3389/fneur.2013.00083] [Citation(s) in RCA: 284] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 06/14/2013] [Indexed: 01/20/2023] Open
Abstract
Fibrillar deposits of highly phosphorylated tau are a key pathological feature of several neurodegenerative tauopathies including Alzheimer's disease (AD) and some frontotemporal dementias. Increasing evidence suggests that the presence of these end-stage neurofibrillary lesions do not cause neuronal loss, but rather that alterations to soluble tau proteins induce neurodegeneration. In particular, aberrant tau phosphorylation is acknowledged to be a key disease process, influencing tau structure, distribution, and function in neurons. Although typically described as a cytosolic protein that associates with microtubules and regulates axonal transport, several additional functions of tau have recently been demonstrated, including roles in DNA stabilization, and synaptic function. Most recently, studies examining the trans-synaptic spread of tau pathology in disease models have suggested a potential role for extracellular tau in cell signaling pathways intrinsic to neurodegeneration. Here we review the evidence showing that tau phosphorylation plays a key role in neurodegenerative tauopathies. We also comment on the tractability of altering phosphorylation-dependent tau functions for therapeutic intervention in AD and related disorders.
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Affiliation(s)
- Wendy Noble
- Department of Neuroscience, King's College London, Institute of Psychiatry , London , UK
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10
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Forest SK, Acker CM, d'Abramo C, Davies P. Methods for measuring tau pathology in transgenic mouse models. J Alzheimers Dis 2013; 33:463-71. [PMID: 22976073 DOI: 10.3233/jad-2012-121354] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In Alzheimer's disease (AD) and tauopathies, tau becomes hyperphosphorylated, undergoes a conformational change, and becomes aggregated and insoluble. There are three methods commonly used to study the insoluble tau fraction, two that utilize detergents (Sarkosyl and RIPA) and another that does not (insoluble). However, these methods require large amounts of homogenate for a relatively low yield of the insoluble fraction, which can be problematic when dealing with small tissue samples. Furthermore, the most common way of analyzing this material is through densitometry of immunoblots, offering only semiquantitative measurements. We provide a comparison of the three methods commonly used (Sarksoyl, RIPA, and insoluble) through immunoblot and ELISA analyses. Finally, we tested a new method to determine aggregated tau levels, utilizing a monoantibody tau ELISA. The insoluble fractions of four different mouse models (P301 L, htau, wild type, and knockout) as well as human AD and control brains were examined. There were significant correlations between the three insoluble methods for both total tau and pS396/404 tau measured by immunoblot or ELISA analyses. Additionally, the results from the ELISA method correlated significantly with those from immunoblot analyses. Finally, the monoantibody assay on the lysate significantly correlated with the total tau ELISAs performed on the three insoluble preparations. Taken together, these results suggest that all three insoluble preparation methods offer similar results for measuring insoluble tau in either mouse or human brains. In addition the new monoantibody ELISA offers a simple quantitative method to measure the amount of aggregated tau in both human and mouse brains.
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Affiliation(s)
- Stefanie K Forest
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
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Martić S, Beheshti S, Rains MK, Kraatz HB. Electrochemical investigations into Tau protein phosphorylations. Analyst 2012; 137:2042-6. [PMID: 22441328 DOI: 10.1039/c2an35097a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hyperphosphorylation of Tau, a protein that stabilizes microtubules, leads to the breakdown of the microtubular structure and ultimately to the formation of neurofibrillar tangles within neurons. Here, we report monitoring of Tau phosphorylations electrochemically, using Tau protein films chemically linked to gold surfaces and 5'-γ-ferrocenyl (Fc) adenosine triphosphate (Fc-ATP) as a co-substrate. Fc-phosphorylation reactions of Tau are explored using the three protein kinases, glycogen synthase kinase (GSK-3β), sarcoma (Src)-related kinase, and protein kinase A (PKA), which catalyze Fc-phosphorylation of different residues and regions within Tau. The kinetic parameters of the biochemical process (K(M) and V(max)) were determined.
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Affiliation(s)
- Sanela Martić
- Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, Canada
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Upper airway dysfunction of Tau-P301L mice correlates with tauopathy in midbrain and ponto-medullary brainstem nuclei. J Neurosci 2010; 30:1810-21. [PMID: 20130190 DOI: 10.1523/jneurosci.5261-09.2010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Tauopathy comprises hyperphosphorylation of the microtubule-associated protein tau, causing intracellular aggregation and accumulation as neurofibrillary tangles and neuropil treads. Some primary tauopathies are linked to mutations in the MAPT gene coding for protein tau, but most are sporadic with unknown causes. Also, in Alzheimer's disease, the most frequent secondary tauopathy, neither the cause nor the pathological mechanisms and repercussions are understood. Transgenic mice expressing mutant Tau-P301L suffer cognitive and motor defects and die prematurely from unknown causes. Here, in situ electrophysiology in symptomatic Tau-P301L mice (7-8 months of age) revealed reduced postinspiratory discharges of laryngeal motor outputs that control laryngeal constrictor muscles. Under high chemical drive (hypercapnia), postinspiratory discharge was nearly abolished, whereas laryngeal inspiratory discharge was increased disproportionally. The latter may suggest a shift of postinspiratory laryngeal constrictor activity into inspiration. In vivo double-chamber plethysmography of Tau-P301L mice showed significantly reduced respiratory airflow but significantly increased chest movements during baseline breathing, but particularly in hypercapnia, confirming a significant increase in inspiratory resistive load. Histological analysis demonstrated hyperphosphorylated tau in brainstem nuclei, directly or indirectly involved in upper airway motor control (i.e., the Kölliker-Fuse, periaqueductal gray, and intermediate reticular nuclei). In contrast, young Tau-P301L mice did not show breathing disorders or brainstem tauopathy. Consequently, in aging Tau-P301L mice, progressive upper airway dysfunction is linked to progressive tauopathy in identified neural circuits. Because patients with tauopathy suffer from upper airway dysfunction, the Tau-P301L mice can serve as an experimental model to study disease-specific synaptic dysfunction in well defined functional neural circuits.
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The cAMP-dependent protein kinase inhibitor H-89 attenuates the bioluminescence signal produced by Renilla Luciferase. PLoS One 2009; 4:e5642. [PMID: 19461967 PMCID: PMC2680982 DOI: 10.1371/journal.pone.0005642] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 04/21/2009] [Indexed: 11/19/2022] Open
Abstract
Background Investigations into the regulation and functional roles of kinases such as cAMP-dependent protein kinase (PKA) increasingly rely on cellular assays. Currently, there are a number of bioluminescence-based assays, for example reporter gene assays, that allow the study of the regulation, activity, and functional effects of PKA in the cellular context. Additionally there are continuing efforts to engineer improved biosensors that are capable of detecting real-time PKA signaling dynamics in cells. These cell-based assays are often utilized to test the involvement of PKA-dependent processes by using H-89, a reversible competitive inhibitor of PKA. Principal Findings We present here data to show that H-89, in addition to being a competitive PKA inhibitor, attenuates the bioluminescence signal produced by Renilla luciferase (RLuc) variants in a population of cells and also in single cells. Using 10 µM of luciferase substrate and 10 µM H-89, we observed that the signal from RLuc and RLuc8, an eight-point mutation variant of RLuc, in cells was reduced to 50% (±15%) and 54% (±14%) of controls exposed to the vehicle alone, respectively. In vitro, we showed that H-89 decreased the RLuc8 bioluminescence signal but did not compete with coelenterazine-h for the RLuc8 active site, and also did not affect the activity of Firefly luciferase. By contrast, another competitive inhibitor of PKA, KT5720, did not affect the activity of RLuc8. Significance The identification and characterization of the adverse effect of H-89 on RLuc signal will help deconvolute data previously generated from RLuc-based assays looking at the functional effects of PKA signaling. In addition, for the current application and future development of bioluminscence assays, KT5720 is identified as a more suitable PKA inhibitor to be used in conjunction with RLuc-based assays. These principal findings also provide an important lesson to fully consider all of the potential effects of experimental conditions on a cell-based assay readout before drawing conclusions from the data.
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Sadik G, Tanaka T, Kato K, Yamamori H, Nessa BN, Morihara T, Takeda M. Phosphorylation of tau at Ser214 mediates its interaction with 14-3-3 protein: implications for the mechanism of tau aggregation. J Neurochem 2008; 108:33-43. [PMID: 19014373 DOI: 10.1111/j.1471-4159.2008.05716.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The microtubule associated protein tau is a major component of neurofibrillary tangles in Alzheimer disease brain, however the neuropathological processes behind the formation of neurofibrillary tangles are still unclear. Previously, 14-3-3 proteins were reported to bind with tau. 14-3-3 Proteins usually bind their targets through specific serine/threonine -phosphorylated motifs. Therefore, the interaction of tau with 14-3-3 mediated by phosphorylation was investigated. In this study, we show that the phosphorylation of tau by either protein kinase A (PKA) or protein kinase B (PKB) enhances the binding of tau with 14-3-3 in vitro. The affinity between tau and 14-3-3 is increased 12- to 14-fold by phosphorylation as determined by real time surface plasmon resonance studies. Mutational analyses revealed that Ser214 is critical for the phosphorylation-mediated interaction of tau with 14-3-3. Finally, in vitro aggregation assays demonstrated that phosphorylation by PKA/PKB inhibits the formation of aggregates/filaments of tau induced by 14-3-3. As the phosphorylation at Ser214 is up-regulated in fetal brain, tau's interaction with 14-3-3 may have a significant role in the organization of the microtubule cytoskeleton in development. Also as the phosphorylation at Ser214 is up-regulated in Alzheimer's disease brain, tau's interaction with 14-3-3 might be involved in the pathology of this disease.
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Affiliation(s)
- Golam Sadik
- Department of Psychiatry, Osaka University Graduate School of Medicine, Osaka, Japan
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15
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Espinoza M, de Silva R, Dickson DW, Davies P. Differential incorporation of tau isoforms in Alzheimer's disease. J Alzheimers Dis 2008; 14:1-16. [PMID: 18525123 DOI: 10.3233/jad-2008-14101] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
There are 6 different isoforms of tau expressed in the adult human brain, and little information is available on the cellular distribution of the isoforms. Tau inclusions are found in neurons and occasionally glia in a variety of diseases. Previous studies conducted on brain homogenates suggested that tau isoforms might be differentially incorporated into inclusions. To further elucidate the complex issue of tau isoform composition in Alzheimer's disease (AD) and other neurodegenerative diseases, monoclonal antibodies that differentiate between tau containing residues encoded by exon 10 (4R tau) and tau lacking exon 10 residues (3R tau) were used in single and double labeling immunohistochemistry as well as biochemical analyses of tau isolated from AD and other neurodegenerative diseases. Immunohistochemical analysis of the hippocampus in 34 AD cases performed with these antibodies showed both 3R and 4R tau isoforms in tangles. While biochemical studies showed that both isoforms were present in insoluble tau aggregates in AD hippocampus and cortex, not all tangles appear to be labeled with the 3R and 4R tau specific monoclonal antibodies. Similar studies in progressive supranuclear palsy and Pick's disease confirmed that these diseases were characterized by incorporation of specific isoforms in fibrillar lesions, but lesions in neither disease were exclusively composed of 3R tau or 4R tau isoforms.
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Affiliation(s)
- Marisol Espinoza
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer 526, Bronx, NY 10461, USA
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Creighton J, Zhu B, Alexeyev M, Stevens T. Spectrin-anchored phosphodiesterase 4D4 restricts cAMP from disrupting microtubules and inducing endothelial cell gap formation. J Cell Sci 2007; 121:110-9. [PMID: 18073242 DOI: 10.1242/jcs.011692] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dynamic cAMP fluctuations that are restricted to a sub-plasma-membrane domain strengthen endothelial barrier integrity. Phosphodiesterases (PDEs) localize within this domain where they limit cAMP diffusion into the bulk cytosolic compartment; however, the molecular identity of PDEs responsible for endothelial cell membrane cAMP compartmentation remain poorly understood. Our present findings reveal that the D4 splice variant of the PDE4 phosphodiesterase family - PDE4D4 - is expressed in pulmonary microvascular endothelial cells, and is found in plasma membrane fractions. PDE4D4 interacts with alpha II spectrin within this membrane domain. Although constitutive PDE4D4 activity limits cAMP access to the bulk cytosol, inhibiting its activity permits cAMP to access a cytosolic domain that is rich in microtubules, where it promotes protein kinase A (PKA) phosphorylation of tau at Ser214. Such phosphorylation reorganizes microtubules and induces interendothelial cell gap formation. Thus, spectrin-anchored PDE4D4 shapes the physiological response to cAMP by directing it to barrier-enhancing effectors while limiting PKA-mediated microtubule reorganization.
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Affiliation(s)
- Judy Creighton
- Center for Lung Biology, The University of South Alabama College of Medicine, Mobile, AL 36688, USA
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Sennvik K, Boekhoorn K, Lasrado R, Terwel D, Verhaeghe S, Korr H, Schmitz C, Tomiyama T, Mori H, Krugers H, Joels M, Ramakers GJA, Lucassen PJ, Van Leuven F. Tau-4R suppresses proliferation and promotes neuronal differentiation in the hippocampus of tau knockin/knockout mice. FASEB J 2007; 21:2149-61. [PMID: 17341679 DOI: 10.1096/fj.06-7735com] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Differential isoform expression and phosphorylation of protein tau are believed to regulate the assembly and stabilization of microtubuli in fetal and adult neurons. To define the functions of tau in the developing and adult brain, we generated transgenic mice expressing the human tau-4R/2N (htau-4R) isoform on a murine tau null background, by a knockout/knockin approach (tau-KOKI). The main findings in these mice were the significant increases in hippocampal volume and neuronal number, which were sustained throughout adult life and paralleled by improved cognitive functioning. The increase in hippocampal size was found to be due to increased neurogenesis and neuronal survival. Proliferation and neuronal differentiation were further analyzed in primary hippocampal cultures from tau-KOKI mice, before and after htau-4R expression onset. In absence of tau, proliferation increased and both neurite and axonal outgrowth were reduced. Htau-4R expression suppressed proliferation, promoted neuronal differentiation, and restored neurite and axonal outgrowth. We suggest that the tau-4R isoform essentially contributes to hippocampal development by controlling proliferation and differentiation of neuronal precursors.
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Affiliation(s)
- Kristina Sennvik
- Experimental Genetics Group, Department Human Genetics, KULeuven-Campus Gasthuisberg ON1-06.602, B-3000 Leuven, Belgium
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18
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Boekhoorn K, Terwel D, Biemans B, Borghgraef P, Wiegert O, Ramakers GJA, de Vos K, Krugers H, Tomiyama T, Mori H, Joels M, van Leuven F, Lucassen PJ. Improved long-term potentiation and memory in young tau-P301L transgenic mice before onset of hyperphosphorylation and tauopathy. J Neurosci 2006; 26:3514-23. [PMID: 16571759 PMCID: PMC6673867 DOI: 10.1523/jneurosci.5425-05.2006] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The microtubule binding protein tau is implicated in neurodegenerative tauopathies, including frontotemporal dementia (FTD) with Parkinsonism caused by diverse mutations in the tau gene. Hyperphosphorylation of tau is considered crucial in the age-related formation of neurofibrillary tangles (NFTs) correlating well with neurotoxicity and cognitive defects. Transgenic mice expressing FTD mutant tau-P301L recapitulate the human pathology with progressive neuronal impairment and accumulation of NFT. Here, we studied tau-P301L mice for parameters of learning and memory at a young age, before hyperphosphorylation and tauopathy were apparent. Unexpectedly, in young tau-P301L mice, increased long-term potentiation in the dentate gyrus was observed in parallel with improved cognitive performance in object recognition tests. Neither tau phosphorylation, neurogenesis, nor other morphological parameters that were analyzed could account for these cognitive changes. The data demonstrate that learning and memory processes in the hippocampus of young tau-P301L mice are not impaired and actually improved in the absence of marked phosphorylation of human tau. We conclude that protein tau plays an important beneficial role in normal neuronal processes of hippocampal memory, and conversely, that not tau mutations per se, but the ensuing hyperphosphorylation must be critical for cognitive decline in tauopathies.
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Andorfer C, Acker CM, Kress Y, Hof PR, Duff K, Davies P. Cell-cycle reentry and cell death in transgenic mice expressing nonmutant human tau isoforms. J Neurosci 2006; 25:5446-54. [PMID: 15930395 PMCID: PMC6725006 DOI: 10.1523/jneurosci.4637-04.2005] [Citation(s) in RCA: 374] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations in the microtubule-associated protein tau gene have been linked to neurofibrillary tangle (NFT) formation in several neurodegenerative diseases known as tauopathies; however, no tau mutations occur in Alzheimer's disease, although this disease is also characterized by NFT formation and cell death. Importantly, the mechanism of tau-mediated neuronal death remains elusive. Aged mice expressing nonmutant human tau in the absence of mouse tau (htau mice) developed NFTs and extensive cell death. The mechanism of neuron death was investigated in htau mice, and surprisingly, the presence of tau filaments did not correlate directly with death within individual cells, suggesting that cell death can occur independently of NFT formation. Our observations show that the mechanism of neurodegeneration involved reexpression of cell-cycle proteins and DNA synthesis, indicating that nonmutant tau pathology and neurodegeneration may be linked via abnormal, incomplete cell-cycle reentry.
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Affiliation(s)
- Cathy Andorfer
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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20
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Terwel D, Lasrado R, Snauwaert J, Vandeweert E, Van Haesendonck C, Borghgraef P, Van Leuven F. Changed conformation of mutant Tau-P301L underlies the moribund tauopathy, absent in progressive, nonlethal axonopathy of Tau-4R/2N transgenic mice. J Biol Chem 2004; 280:3963-73. [PMID: 15509565 DOI: 10.1074/jbc.m409876200] [Citation(s) in RCA: 198] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein tau-3R/4R isoform ratio and phosphorylation regulates binding to microtubules and, when disturbed by aging or mutations, results in diverse tauopathies and in neurodegeneration. The underlying mechanisms were studied here in three transgenic mouse strains with identical genetic background, all expressing the tau-4R/2N isoform driven specifically in neurons by the thy1 gene promoter. Two strains, expressing human tau-4R/2N or mutant tau-4R/2N-P301L at similar, moderate levels, developed very different phenotypes. Tau-4R/2N mice became motor-impaired already around age 6-8 weeks, accompanied by axonopathy (dilatations, spheroids), but no tau aggregates, and surviving normally. In contrast, tau-P301L mice developed neurofibrillary tangles from age 6 months, without axonal dilatations and, despite only minor motor problems, all succumbing before the age of 13 months. The third strain, obtained by tau knock-out/knock-in (tau-KOKI), expressed normal levels of wild-type human tau-4R/2N replacing all mouse tau isoforms. Tau-KOKI mice survived normally with minor motor problems late in life and without any obvious pathology. Biochemically, a fraction of neuronal tau in aging tau-P301L mice was hyperphosphorylated concomitant with conformational changes and aggregation, but overall, tau-4R/2N was actually more phosphorylated than tau-P301L. Significantly, tau with changed conformation and with hyperphosphorylation colocalized in the same neurons in aging tau-P301L mice. Taken together, we conclude that excessive binding of tau-4R/2N as opposed to reduced binding of tau-P301L to microtubules is responsible for the development of axonopathy and tauopathy, respectively, in tau-4R/2N and tau-P301L mice and that the conformational change of tau-P301L is a major determinant in triggering the tauopathy.
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Affiliation(s)
- Dick Terwel
- Experimental Genetics Group, Department of Human Genetics, KU Leuven, B-3000 Leuven, Belgium
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21
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Andorfer C, Kress Y, Espinoza M, de Silva R, Tucker KL, Barde YA, Duff K, Davies P. Hyperphosphorylation and aggregation of tau in mice expressing normal human tau isoforms. J Neurochem 2003; 86:582-90. [PMID: 12859672 DOI: 10.1046/j.1471-4159.2003.01879.x] [Citation(s) in RCA: 531] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neurofibrillary tangles are composed of insoluble aggregates of the microtubule-associated protein tau. In Alzheimer's disease the accumulation of neurofibrillary tangles occurs in the absence of tau mutations. Here we present mice that develop pathology from non-mutant human tau, in the absence of other exogenous factors, including beta-amyloid. The pathology in these mice is Alzheimer-like, with hyperphosphorylated tau accumulating as aggregated paired helical filaments. This pathologic tau accumulates in the cell bodies and dendrites of neurons in a spatiotemporally relevant distribution.
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Affiliation(s)
- Cathy Andorfer
- Departments of Neuroscience and Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
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22
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Bu B, Klunemann H, Suzuki K, Li J, Bird T, Jin LW, Vincent I. Niemann-Pick disease type C yields possible clue for why cerebellar neurons do not form neurofibrillary tangles. Neurobiol Dis 2002; 11:285-97. [PMID: 12505421 DOI: 10.1006/nbdi.2002.0551] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
It is unknown why cerebellar neurons resist neurofibrillary tangle (NFT) formation. In Niemann-Pick disease Type C (NPC), NFT-mediated neurodegeneration occurs throughout brain, but the cerebellum degenerates conspicuously without NFT. To understand why, we have studied markers of NFT pathogenesis in cerebellum from 17 NPC cases, all having abundant NFT in forebrain. Remarkably, we found that NPC cerebella display several early markers of NFT formation, i.e., hyperphosphorylated tau and an array of cell cycle regulators, suggesting that cerebellar neurons in NPC undergo similar modifications as other neurons that develop NFT. However, cerebellar neurons are deficient in tau, the building block of NFT, and this may be one reason for their inability to form NFT. Even without NFT, cerebellar neurodegeneration may be triggered by the inappropriate activation of the cell cycle cdc2 kinase, and the npc-1 murine model provides an opportunity to test this hypothesis.
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Affiliation(s)
- Bitao Bu
- Department of Pathology, University of Washington, Seattle, 98195, USA
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23
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Xu G, Gonzales V, Borchelt DR. Abeta deposition does not cause the aggregation of endogenous tau in transgenic mice. Alzheimer Dis Assoc Disord 2002; 16:196-201. [PMID: 12218652 DOI: 10.1097/00002093-200207000-00011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In Alzheimer disease, the extracellular deposition of beta-amyloid (Abeta) in the brain is accompanied by the intracellular accumulation of aggregated forms of hyperphosphorylated tau. In developing animal models of AD, the authors and others have been able to reproduce extracellular amyloid pathology in the brains of mice by expressing mutant amyloid precursor proteins (APP). The co-expression of APP with mutant presenilin leads to a dramatic acceleration in Abeta deposition, leading to very high amyloid burdens in mice. In the current study, the authors have examined whether the brains of mice with high burdens of amyloid deposition also contain aggregated forms of tau, using a cellulose acetate filter trap assay. Although discrete accumulations of phosphorylated tau immunoreactivity were apparent in neurites proximal to cored deposits of Abeta, little if any of this tau was in a SDS-resistant state of aggregation. By contrast, the brains of AD patients contained large amounts of aggregated tau. Overall, this study demonstrates that, in mice, deposition of Abeta does not cause endogenous tau to aggregate.
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Affiliation(s)
- Guilian Xu
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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24
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Cassimeris L, Spittle C. Regulation of microtubule-associated proteins. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 210:163-226. [PMID: 11580206 DOI: 10.1016/s0074-7696(01)10006-9] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microtubule-associated proteins (MAPs) function to regulate the assembly dynamics and organization of microtubule polymers. Upstream regulation of MAP activities is the major mechanism used by cells to modify and control microtubule assembly and organization. This review summarizes the functional activities of MAPs found in animal cells and discusses how these MAPs are regulated. Mechanisms controlling gene expression, isoform-specific expression, protein localization, phosphorylation, and degradation are discussed. Additional regulatory mechanisms include synergy or competition between MAPs and the activities of cofactors or binding partners. For each MAP it is likely that regulation in vivo reflects a composite of multiple regulatory mechanisms.
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Affiliation(s)
- L Cassimeris
- Department of Biological Sciences, Lehigh University Bethlehem, Pennsylvania 18015, USA
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