1
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Lavrsen K, Rajendraprasad G, Leda M, Eibes S, Vitiello E, Katopodis V, Goryachev AB, Barisic M. Microtubule detyrosination drives symmetry breaking to polarize cells for directed cell migration. Proc Natl Acad Sci U S A 2023; 120:e2300322120. [PMID: 37216553 PMCID: PMC10235987 DOI: 10.1073/pnas.2300322120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/21/2023] [Indexed: 05/24/2023] Open
Abstract
To initiate directed movement, cells must become polarized, establishing a protrusive leading edge and a contractile trailing edge. This symmetry-breaking process involves reorganization of cytoskeleton and asymmetric distribution of regulatory molecules. However, what triggers and maintains this asymmetry during cell migration remains largely elusive. Here, we established a micropatterning-based 1D motility assay to investigate the molecular basis of symmetry breaking required for directed cell migration. We show that microtubule (MT) detyrosination drives cell polarization by directing kinesin-1-based transport of the adenomatous polyposis coli (APC) protein to cortical sites. This is essential for the formation of cell's leading edge during 1D and 3D cell migration. These data, combined with biophysical modeling, unveil a key role for MT detyrosination in the generation of a positive feedback loop linking MT dynamics and kinesin-1-based transport. Thus, symmetry breaking during cell polarization relies on a feedback loop driven by MT detyrosination that supports directed cell migration.
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Affiliation(s)
- Kirstine Lavrsen
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
| | - Girish Rajendraprasad
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
| | - Marcin Leda
- Centre for Synthetic and Systems Biology, University of Edinburgh, EdinburghEH9 3BF, United Kingdom
| | - Susana Eibes
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
| | - Elisa Vitiello
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
| | - Vasileios Katopodis
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
| | - Andrew B. Goryachev
- Centre for Synthetic and Systems Biology, University of Edinburgh, EdinburghEH9 3BF, United Kingdom
| | - Marin Barisic
- Cell Division and Cytoskeleton, Danish Cancer Society Research Center, 2100Copenhagen, Denmark
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200Copenhagen, Denmark
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2
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Jansen KI, Iwanski MK, Burute M, Kapitein LC. A live-cell marker to visualize the dynamics of stable microtubules throughout the cell cycle. J Cell Biol 2023; 222:e202106105. [PMID: 36880745 PMCID: PMC9998657 DOI: 10.1083/jcb.202106105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 01/08/2022] [Accepted: 02/13/2023] [Indexed: 03/08/2023] Open
Abstract
The microtubule (MT) cytoskeleton underlies processes such as intracellular transport and cell division. Immunolabeling for posttranslational modifications of tubulin has revealed the presence of different MT subsets, which are believed to differ in stability and function. Whereas dynamic MTs can readily be studied using live-cell plus-end markers, the dynamics of stable MTs have remained obscure due to a lack of tools to directly visualize these MTs in living cells. Here, we present StableMARK (Stable Microtubule-Associated Rigor-Kinesin), a live-cell marker to visualize stable MTs with high spatiotemporal resolution. We demonstrate that a rigor mutant of Kinesin-1 selectively binds to stable MTs without affecting MT organization and organelle transport. These MTs are long-lived, undergo continuous remodeling, and often do not depolymerize upon laser-based severing. Using this marker, we could visualize the spatiotemporal regulation of MT stability before, during, and after cell division. Thus, this live-cell marker enables the exploration of different MT subsets and how they contribute to cellular organization and transport.
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Affiliation(s)
- Klara I. Jansen
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Malina K. Iwanski
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Mithila Burute
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Lukas C. Kapitein
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, Netherlands
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3
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Bär J, Popp Y, Bucher M, Mikhaylova M. Direct and indirect effects of tubulin post-translational modifications on microtubule stability: Insights and regulations. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119241. [PMID: 35181405 DOI: 10.1016/j.bbamcr.2022.119241] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 12/17/2022]
Abstract
Microtubules (MTs) mediate various cellular functions such as structural support, chromosome segregation, and intracellular transport. To achieve this, the pivotal properties of MTs have to be changeable and tightly controlled. This is enabled by a high variety of tubulin posttranslational modifications, which influence MT properties directly, via altering the MT lattice structurally, or indirectly by changing MT interaction partners. Here, the distinction between these direct and indirect effects of MT PTMs are exemplified by acetylation of the luminal α-tubulin K40 resulting in decreased rigidity of MTs, and by MT detyrosination which decreases interaction with depolymerizing proteins, thus causing more stable MTs. We discuss how these PTMs are reversed and regulated, e.g. on the level of enzyme transcription, localization, and activity via various signalling pathways including the conventional calcium-dependent proteases calpains and how advances in microscopy techniques and development of live-sensors facilitate the understanding of MT PTM interaction and effects.
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Affiliation(s)
- Julia Bär
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany; Guest Group "Neuronal Protein Transport", Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
| | - Yannes Popp
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany; Guest Group "Neuronal Protein Transport", Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
| | - Michael Bucher
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany; Guest Group "Neuronal Protein Transport", Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
| | - Marina Mikhaylova
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany; Guest Group "Neuronal Protein Transport", Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
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4
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Piermarini E, Akarsu S, Connors T, Kneussel M, Lane MA, Morfini G, Karabay A, Baas PW, Qiang L. Modeling gain-of-function and loss-of-function components of SPAST-based hereditary spastic paraplegia using transgenic mice. Hum Mol Genet 2021; 31:1844-1859. [PMID: 34935948 PMCID: PMC9169457 DOI: 10.1093/hmg/ddab367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 12/24/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) is a disease in which dieback degeneration of corticospinal tracts, accompanied by axonal swellings, leads to gait deficiencies. SPG4-HSP, the most common form of the disease, results from mutations of human spastin gene (SPAST), which is the gene that encodes spastin, a microtubule-severing protein. The lack of a vertebrate model that recapitulates both the etiology and symptoms of SPG4-HSP has stymied the development of effective therapies for the disease. hSPAST-C448Y mice, which express human mutant spastin at the ROSA26 locus, display corticospinal dieback and gait deficiencies but not axonal swellings. On the other hand, mouse spastin gene (Spast)-knockout (KO) mice display axonal swellings but not corticospinal dieback or gait deficiencies. One possibility is that reduced spastin function, resulting in axonal swellings, is not the cause of the disease but exacerbates the toxic effects of the mutant protein. To explore this idea, Spast-KO and hSPAST-C448Y mice were crossbred, and the offspring were compared with the parental lines via histological and behavioral analyses. The crossbred animals displayed axonal swellings as well as earlier onset, worsened gait deficiencies and corticospinal dieback compared with the hSPAST-C448Y mouse. These results, together with observations on changes in histone deacetylases 6 and tubulin modifications in the axon, indicate that each of these three transgenic mouse lines is valuable for investigating a different component of the disease pathology. Moreover, the crossbred mice are the best vertebrate model to date for testing potential therapies for SPG4-HSP.
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Affiliation(s)
- Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Seyma Akarsu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA,Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul 34469, Turkey
| | - Theresa Connors
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Matthias Kneussel
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Michael A Lane
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Arzu Karabay
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul 34469, Turkey
| | - Peter W Baas
- To whom correspondence should be addressed at: Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA. Tel: +1 2159918311; Fax: +1 2158439082; ; Tel: +1 2159918298;
| | - Liang Qiang
- To whom correspondence should be addressed at: Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA. Tel: +1 2159918311; Fax: +1 2158439082; ; Tel: +1 2159918298;
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5
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Morales-Tarré O, Alonso-Bastida R, Arcos-Encarnación B, Pérez-Martínez L, Encarnación-Guevara S. Protein lysine acetylation and its role in different human pathologies: a proteomic approach. Expert Rev Proteomics 2021; 18:949-975. [PMID: 34791964 DOI: 10.1080/14789450.2021.2007766] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Lysine acetylation is a reversible post-translational modification (PTM) regulated through the action of specific types of enzymes: lysine acetyltransferases (KATs) and lysine deacetylases (HDACs), in addition to bromodomains, which are a group of conserved domains which identify acetylated lysine residues, several of the players in the process of protein acetylation, including enzymes and bromodomain-containing proteins, have been related to the progression of several diseases. The combination of high-resolution mass spectrometry-based proteomics, and immunoprecipitation to enrich acetylated peptides has contributed in recent years to expand the knowledge about this PTM described initially in histones and nuclear proteins, and is currently reported in more than 5000 human proteins, that are regulated by this PTM. AREAS COVERED This review presents an overview of the main participant elements, the scenario in the development of protein lysine acetylation, and its role in different human pathologies. EXPERT OPINION Acetylation targets are practically all cellular processes in eukaryotes and prokaryotes organisms. Consequently, this modification has been linked to many pathologies like cancer, viral infection, obesity, diabetes, cardiovascular, and nervous system-associated diseases, to mention a few relevant examples. Accordingly, some intermediate mediators in the acetylation process have been projected as therapeutic targets.
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Affiliation(s)
- Orlando Morales-Tarré
- Laboratorio de Proteómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Ramiro Alonso-Bastida
- Laboratorio de Proteómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Bolivar Arcos-Encarnación
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular Y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Leonor Pérez-Martínez
- Laboratorio de Neuroinmunobiología, Departamento de Medicina Molecular Y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sergio Encarnación-Guevara
- Laboratorio de Proteómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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6
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Wu Y, Ding Y, Zheng X, Liao K. The molecular chaperone Hsp90 maintains Golgi organization and vesicular trafficking by regulating microtubule stability. J Mol Cell Biol 2021; 12:448-461. [PMID: 31560394 PMCID: PMC7333477 DOI: 10.1093/jmcb/mjz093] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 07/05/2019] [Accepted: 09/03/2019] [Indexed: 11/14/2022] Open
Abstract
Hsp90 is an abundant and special molecular chaperone considered to be the regulator of many transcription factors and signaling kinases. Its high abundance is indicative of its involvement in some more fundamental processes. In this study, we provide evidence that Hsp90 is required for microtubule stabilization, Golgi organization, and vesicular trafficking. We showed that Hsp90 is bound to microtubule-associated protein 4 (MAP4), which is essential for maintaining microtubule acetylation and stabilization. Hsp90 depletion led to the decrease in MAP4, causing microtubule deacetylation and destabilization. Furthermore, in Hsp90-depleted cells, the Golgi apparatus was fragmented and anterograde vesicle trafficking was impaired, with phenotypes similar to those induced by silencing MAP4. These disruptive effects of Hsp90 depletion could be rescued by the expression of exogenous MAP4 or the treatment of trichostatin A that increases microtubule acetylation as well as stability. Thus, microtubule stability is an essential cellular event regulated by Hsp90.
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Affiliation(s)
- Yuan Wu
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Yubo Ding
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiudan Zheng
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Kan Liao
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
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7
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Expression of α-Tubulin Acetyltransferase 1 and Tubulin Acetylation as Selective Forces in Cell Competition. Cells 2021; 10:cells10020390. [PMID: 33672816 PMCID: PMC7918103 DOI: 10.3390/cells10020390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 02/09/2021] [Indexed: 12/23/2022] Open
Abstract
The wound healing response of fibroblasts critically depends on the primary cilium, a sensory organelle protruding into the environment and comprising a stable axonemal structure. A characteristic marker for primary cilia is acetylation of axonemal tubulin. Although formation of primary cilia is under cell cycle control, the environmental cues affecting ciliation are not fully understood. Our purpose was, therefore, to study the impact of culture conditions on cilia formation in NIH3T3 fibroblasts. We quantified ciliation in different NIH3T3 sub-cell lines and culture conditions by immunodetection of primary cilia and counting. Quantitative Western blotting, qRT-PCR, and proliferation assays completed our investigation. We observed large differences between NIH3T3 sub-cell lines in their ability to generate acetylated primary cilia that correlated with cytoplasmic tubulin acetylation. We found no increased activity of the major tubulin deacetylase, HDAC6, but instead reduced expression of the α-tubulin acetyltransferase 1 (Atat1) as being causative. Our observations demonstrate that cells with reduced expression of Atat1 and tubulin acetylation proliferate faster, eventually displacing all other cells in the population. Expression of Atat1 and tubulin acetylation are therefore selective forces in cell competition.
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8
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Tubulin modifying enzymes as target for the treatment oftau-related diseases. Pharmacol Ther 2020; 218:107681. [PMID: 32961263 DOI: 10.1016/j.pharmthera.2020.107681] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/09/2020] [Indexed: 01/17/2023]
Abstract
In the brain of patients with Alzheimer's disease (AD), the number and length of microtubules (MTs) are significantly and selectively reduced. MTs are involved in a wide range of cellular functions, and defects of the microtubular system have emerged as a unifying hypothesis for the heterogeneous and variable clinical presentations of AD. MTs orchestrate their numerous functions through the spatiotemporal regulation of the binding of specialised microtubule-associated proteins (MAPs) and molecular motors. Covalent posttranslational modifications (PTMs) on the tubulin C-termini that protrude at the surface of MTs regulate the binding of these effectors. In neurons, MAP tau is highly abundant and its abnormal dissociation from MTs in the axon, cellular mislocalization and hyperphosphorylation, are primary events leading to neuronal death. Consequently, compounds targeting tau phosphorylation or aggregation are currently evaluated but their clinical significance has not been demonstrated yet. In this review, we discuss the emerging link between tubulin PTMs and tau dysfunction. In neurons, high levels of glutamylation and detyrosination profoundly impact the physicochemical properties at the surface of MTs. Moreover, in patients with early-onset progressive neurodegeneration, deleterious mutations in enzymes involved in modifying MTs at the surface have recently been identified, underscoring the importance of this enzymatic machinery in neurology. We postulate that pharmacologically targeting the tubulin-modifying enzymes holds promise as therapeutic approach for the treatment of neurodegenerative diseases.
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9
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Lang UE, Torres R, Cheung C, Vladar EK, McCalmont TH, Kim J, Judson-Torres RL. Ciliation Index Is a Useful Diagnostic Tool in Challenging Spitzoid Melanocytic Neoplasms. J Invest Dermatol 2020; 140:1401-1409.e2. [PMID: 31978411 DOI: 10.1016/j.jid.2019.11.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/08/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022]
Abstract
The loss of primary cilia on melanocytes is a useful biomarker for the distinction of melanoma from conventional melanocytic nevi. It is unknown whether ciliation status is beneficial for diagnosing spitzoid tumors-a subclass of melanomas that present inherently ambiguous histology and are challenging to classify. We evaluated the Ciliation Index (CI) in 68 cases of spitzoid tumors ranging from Spitz nevi and atypical Spitz tumors to spitzoid melanoma. We found a significant decrease in CI within the spitzoid melanoma group when compared with either the Spitz nevi or atypical Spitz tumors groups. In addition, we used a machine-learning-based algorithm to determine the value of CI when considered in combination with other histopathologic and molecular features commonly used for diagnosis. We found that a low CI was consistently ranked as a top predictive feature in the diagnosis of malignancy. Predictive models trained on only the top four predictive features (CI, asymmetry, hyperchromatism, and cytologic atypia) outperformed standard histologic assessment in an independent validation cohort of 56 additional cases. The results provide an alternative approach to evaluate diagnostically challenging melanocytic lesions, and further support the use of CI as an ancillary diagnostic test.
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Affiliation(s)
- Ursula E Lang
- Department of Pathology, Dermatopathology Service, University of California, San Francisco, CA, USA; Department of Dermatology, University of California, San Francisco, CA, USA.
| | - Rodrigo Torres
- Department of Dermatology, University of California, San Francisco, CA, USA
| | - Christine Cheung
- Department of Pathology, Stanford University Medical Center, Stanford, CA, USA
| | - Eszter K Vladar
- Department of Pathology, Stanford University Medical Center, Stanford, CA, USA; Department of Medicine, Division of Pulmonary Sciences and Critical Care Medicine, Aurora, CO, USA; Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Timothy H McCalmont
- Department of Pathology, Dermatopathology Service, University of California, San Francisco, CA, USA; Department of Dermatology, University of California, San Francisco, CA, USA
| | - Jinah Kim
- Department of Pathology, Stanford University Medical Center, Stanford, CA, USA; Palo Alto Medical Foundation, Division of Dermatopathology, Palo Alto, CA, USA
| | - Robert L Judson-Torres
- Department of Dermatology, University of California, San Francisco, CA, USA; Department of Dermatology, University of Utah School of Medicine, Salt Lake City, UT, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
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10
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Rolls MM, Thyagarajan P, Feng C. Microtubule dynamics in healthy and injured neurons. Dev Neurobiol 2020; 81:321-332. [PMID: 32291942 DOI: 10.1002/dneu.22746] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 04/08/2020] [Indexed: 12/28/2022]
Abstract
Most neurons must last a lifetime and their microtubule cytoskeleton is an important contributor to their longevity. Neurons have some of the most stable microtubules of all cells, but the tip of every microtubule remains dynamic and, although requiring constant GTP consumption, microtubules are always being rebuilt. While some ongoing level of rebuilding always occurs, overall microtubule stability can be modulated in response to injury and stress as well as the normal developmental process of pruning. Specific microtubule severing proteins act in different contexts to increase microtubule dynamicity and promote degeneration and pruning. After axon injury, complex changes in dynamics occur and these are important for both neuroprotection induced by injury and subsequent outgrowth of a new axon. Understanding how microtubule dynamics is modulated in different scenarios, as well as the impact of the changes in stability, is an important avenue to explore for development of strategies to promote neuroprotection and regeneration.
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Affiliation(s)
- Melissa M Rolls
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Pankajam Thyagarajan
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Chengye Feng
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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11
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The tubulin code and its role in controlling microtubule properties and functions. Nat Rev Mol Cell Biol 2020; 21:307-326. [PMID: 32107477 DOI: 10.1038/s41580-020-0214-3] [Citation(s) in RCA: 408] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 02/07/2023]
Abstract
Microtubules are core components of the eukaryotic cytoskeleton with essential roles in cell division, shaping, motility and intracellular transport. Despite their functional heterogeneity, microtubules have a highly conserved structure made from almost identical molecular building blocks: the tubulin proteins. Alternative tubulin isotypes and a variety of post-translational modifications control the properties and functions of the microtubule cytoskeleton, a concept known as the 'tubulin code'. Here we review the current understanding of the molecular components of the tubulin code and how they impact microtubule properties and functions. We discuss how tubulin isotypes and post-translational modifications control microtubule behaviour at the molecular level and how this translates into physiological functions at the cellular and organism levels. We then go on to show how fine-tuning of microtubule function by some tubulin modifications can affect homeostasis and how perturbation of this fine-tuning can lead to a range of dysfunctions, many of which are linked to human disease.
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12
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Afreen S, Ferreira A. Altered Cytoskeletal Composition and Delayed Neurite Elongation in tau 45-230-Expressing Hippocampal Neurons. Neuroscience 2019; 412:1-15. [PMID: 31158440 DOI: 10.1016/j.neuroscience.2019.05.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/15/2022]
Abstract
Calpain-mediated tau cleavage into the neurotoxic tau45-230 fragment plays an important role in Alzheimer's disease (AD). This tau fragment accumulates mainly in the cytoplasm of degenerating neurons. However, subcellular localization studies indicated that a pool of tau45-230 associates with the cytoskeleton in hippocampal neurons. In the present study, we assessed whether such localization could underlie tau45-230 neurotoxic effects. Quantitative Western blot analysis showed decreased levels of full-length tau bound to microtubules in tau45-230-expressing hippocampal neurons when compared to controls. In addition, the presence of this tau fragment induced a transient increase in tyrosinated tubulin, a marker of unstable microtubules, followed by a significant decrease in the levels of this tubulin isoform. The data obtained also showed a significant reduction in actin filaments in tau45-230-expressing neurons. These changes in microtubules and actin filaments correlated with delayed neurite elongation and axonal differentiation in the presence of this tau fragment. Together, these results suggest that tau45-230 could exert its toxic effects, at least in part, by modifying the composition of the neuronal cytoskeleton and impairing neurite elongation in neurons undergoing degeneration.
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Affiliation(s)
- Sana Afreen
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Adriana Ferreira
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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13
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Sayas CL, Basu S, van der Reijden M, Bustos-Morán E, Liz M, Sousa M, van IJcken WFJ, Avila J, Galjart N. Distinct Functions for Mammalian CLASP1 and -2 During Neurite and Axon Elongation. Front Cell Neurosci 2019; 13:5. [PMID: 30787869 PMCID: PMC6373834 DOI: 10.3389/fncel.2019.00005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 01/08/2019] [Indexed: 01/10/2023] Open
Abstract
Mammalian cytoplasmic linker associated protein 1 and -2 (CLASP1 and -2) are microtubule (MT) plus-end tracking proteins that selectively stabilize MTs at the edge of cells and that promote MT nucleation and growth at the Golgi, thereby sustaining cell polarity. In vitro analysis has shown that CLASPs are MT growth promoting factors. To date, a single CLASP1 isoform (called CLASP1α) has been described, whereas three CLASP2 isoforms are known (CLASP2α, -β, and -γ). Although CLASP2β/γ are enriched in neurons, suggesting isoform-specific functions, it has been proposed that during neurite outgrowth CLASP1 and -2 act in a redundant fashion by modulating MT dynamics downstream of glycogen synthase kinase 3 (GSK3). Here, we show that in differentiating N1E-115 neuroblastoma cells CLASP1 and CLASP2 differ in their accumulation at MT plus-ends and display different sensitivity to GSK3-mediated phosphorylation, and hence regulation. More specifically, western blot (WB) analysis suggests that pharmacological inhibition of GSK3 affects CLASP2 but not CLASP1 phosphorylation and fluorescence-based microscopy data show that GSK3 inhibition leads to an increase in the number of CLASP2-decorated MT ends, as well as to increased CLASP2 staining of individual MT ends, whereas a reduction in the number of CLASP1-decorated ends is observed. Thus, in N1E-115 cells CLASP2 appears to be a prominent target of GSK3 while CLASP1 is less sensitive. Surprisingly, knockdown of either CLASP causes phosphorylation of GSK3, pointing to the existence of feedback loops between CLASPs and GSK3. In addition, CLASP2 depletion also leads to the activation of protein kinase C (PKC). We found that these differences correlate with opposite functions of CLASP1 and CLASP2 during neuronal differentiation, i.e., CLASP1 stimulates neurite extension, whereas CLASP2 inhibits it. Consistent with knockdown results in N1E-115 cells, primary Clasp2 knockout (KO) neurons exhibit early accelerated neurite and axon outgrowth, showing longer axons than control neurons. We propose a model in which neurite outgrowth is fine-tuned by differentially posttranslationally modified isoforms of CLASPs acting at distinct intracellular locations, thereby targeting MT stabilizing activities of the CLASPs and controlling feedback signaling towards upstream kinases. In summary, our findings provide new insight into the roles of neuronal CLASPs, which emerge as regulators acting in different signaling pathways and locally modulating MT behavior during neurite/axon outgrowth.
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Affiliation(s)
- Carmen Laura Sayas
- Department of Cell Biology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands.,Centro de Biología Molecular Severo Ochoa (CSIC-Universidad Autónoma de Madrid (UAM)), Madrid, Spain.,Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna (ULL), Tenerife, Spain
| | - Sreya Basu
- Department of Cell Biology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Michael van der Reijden
- Department of Cell Biology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Eugenio Bustos-Morán
- Centro de Biología Molecular Severo Ochoa (CSIC-Universidad Autónoma de Madrid (UAM)), Madrid, Spain
| | - Marcia Liz
- Instituto de Biologia Molecular e Celular-IBMC and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
| | - Monica Sousa
- Instituto de Biologia Molecular e Celular-IBMC and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
| | - Wilfred F J van IJcken
- Center for Biomics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Jesus Avila
- Centro de Biología Molecular Severo Ochoa (CSIC-Universidad Autónoma de Madrid (UAM)), Madrid, Spain.,Centro Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Niels Galjart
- Department of Cell Biology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
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14
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Tang F, Pan MH, Wan X, Lu Y, Zhang Y, Sun SC. Kif18a regulates Sirt2-mediated tubulin acetylation for spindle organization during mouse oocyte meiosis. Cell Div 2018; 13:9. [PMID: 30459823 PMCID: PMC6234775 DOI: 10.1186/s13008-018-0042-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/26/2018] [Indexed: 12/17/2022] Open
Abstract
Background During oocyte meiosis, the cytoskeleton dynamics, especially spindle organization, are critical for chromosome congression and segregation. However, the roles of the kinesin superfamily in this process are still largely unknown. Results In the present study, Kif18a, a member of the kinesin-8 family, regulated spindle organization through its effects on tubulin acetylation in mouse oocyte meiosis. Our results showed that Kif18a is expressed and mainly localized in the spindle region. Knock down of Kif18a caused the failure of first polar body extrusion, dramatically affecting spindle organization and resulting in severe chromosome misalignment. Further analysis showed that the disruption of Kif18a caused an increase in acetylated tubulin level, which might be the reason for the spindle organization defects after Kif18a knock down in oocyte meiosis, and the decreased expression of deacetylase Sirt2 was found after Kif18a knock down. Moreover, microinjections of tubulin K40R mRNA, which could induce tubulin deacetylation, protected the oocytes from the effects of Kif18a downregulation, resulting in normal spindle morphology in Kif18a-knock down oocytes. Conclusions Taken together, our results showed that Kif18a affected Sirt2-mediated tubulin acetylation level for spindle organization during mouse oocyte meiosis. Our results not only revealed the critical effect of Kif18a on microtubule stability, but also extended our understanding of kinesin activity in meiosis.
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Affiliation(s)
- Feng Tang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Xiang Wan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yujie Lu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yu Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
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15
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Biella G, Fusco F, Nardo E, Bernocchi O, Colombo A, Lichtenthaler SF, Forloni G, Albani D. Sirtuin 2 Inhibition Improves Cognitive Performance and Acts on Amyloid-β Protein Precursor Processing in Two Alzheimer's Disease Mouse Models. J Alzheimers Dis 2018; 53:1193-207. [PMID: 27372638 DOI: 10.3233/jad-151135] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The neuropathological hallmarks of Alzheimer's disease (AD) are extracellular plaques built up by the accumulation of the amyloid-β protein precursor (AβPP)-derived peptide β (Aβ), and intracellular tangles of hyperphosphorylated tau protein. Sirtuin 2 (SIRT2) is a member of the sirtuin family, featuring conserved enzymes with deacetylase activity and involved in several cell molecular pathways. We investigated the importance of SIRT2 inhibition in AD. We inhibited SIRT2 by small molecules (AGK-2, AK-7) and examined AβPP metabolism in H4-SW neuroglioma cells overexpressing AβPP and two AD transgenic mouse models (3xTg-AD and APP23). The in vitro studies suggested that the inhibition of SIRT2 reduced Aβ production; in vivo data showed an improvement of cognitive performance in the novel object recognition test, and an effect on AβPP proteolytic processing leading to a reduction of soluble β-AβPP and an increase of soluble α-AβPP protein. In 3xTg-AD mice, we noticed that total tau protein level rose. Overall, our pre-clinical data support a role for SIRT2 inhibition in the improvement of cognitive performance and the modulation of molecular mechanisms relevant for AD, thus deserving attention as possible therapeutic strategy.
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Affiliation(s)
- Gloria Biella
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
| | - Federica Fusco
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
| | - Emanuele Nardo
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
| | - Ottavia Bernocchi
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
| | - Alessio Colombo
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, Klinikum rechts der Isar, and Institute for Advanced Study, Technische Universität München, Munich, Germany.,Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Gianluigi Forloni
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
| | - Diego Albani
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Milan, Italy
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16
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Wloga D, Joachimiak E, Fabczak H. Tubulin Post-Translational Modifications and Microtubule Dynamics. Int J Mol Sci 2017; 18:ijms18102207. [PMID: 29065455 PMCID: PMC5666887 DOI: 10.3390/ijms18102207] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/12/2017] [Accepted: 10/19/2017] [Indexed: 11/24/2022] Open
Abstract
Microtubules are hollow tube-like polymeric structures composed of α,β-tubulin heterodimers. They play an important role in numerous cellular processes, including intracellular transport, cell motility and segregation of the chromosomes during cell division. Moreover, microtubule doublets or triplets form a scaffold of a cilium, centriole and basal body, respectively. To perform such diverse functions microtubules have to differ in their properties. Post-translational modifications are one of the factors that affect the properties of the tubulin polymer. Here we focus on the direct and indirect effects of post-translational modifications of tubulin on microtubule dynamics.
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Affiliation(s)
- Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
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17
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Hwang ES, Song SB. Nicotinamide is an inhibitor of SIRT1 in vitro, but can be a stimulator in cells. Cell Mol Life Sci 2017; 74:3347-3362. [PMID: 28417163 PMCID: PMC11107671 DOI: 10.1007/s00018-017-2527-8] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 01/15/2023]
Abstract
Nicotinamide (NAM), a form of vitamin B3, plays essential roles in cell physiology through facilitating NAD+ redox homeostasis and providing NAD+ as a substrate to a class of enzymes that catalyze non-redox reactions. These non-redox enzymes include the sirtuin family proteins which deacetylate target proteins while cleaving NAD+ to yield NAM. Since the finding that NAM exerts feedback inhibition to the sirtuin reactions, NAM has been widely used as an inhibitor in the studies where SIRT1, a key member of sirtuins, may have a role in certain cell physiology. However, once administered to cells, NAM is rapidly converted to NAD+ and, therefore, the cellular concentration of NAM decreases rapidly while that of NAD+ increases. The result would be an inhibition of SIRT1 for a limited duration, followed by an increase in the activity. This possibility raises a concern on the validity of the interpretation of the results in the studies that use NAM as a SIRT1 inhibitor. To understand better the effects of cellular administration of NAM, we reviewed published literature in which treatment with NAM was used to inhibit SIRT1 and found that the expected inhibitory effect of NAM was either unreliable or muted in many cases. In addition, studies demonstrated NAM administration stimulates SIRT1 activity and improves the functions of cells and organs. To determine if NAM administration can generate conditions in cells and tissues that are stimulatory to SIRT1, the changes in the cellular levels of NAM and NAD+ reported in the literature were examined and the factors that are involved in the availability of NAD+ to SIRT1 were evaluated. We conclude that NAM treatment can hypothetically be stimulatory to SIRT1.
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Affiliation(s)
- Eun Seong Hwang
- Department of Life Science, University of Seoul, Dongdaemungu, 163 Seoulsiripdaero, Seoul, 02504, Republic of Korea.
| | - Seon Beom Song
- Department of Life Science, University of Seoul, Dongdaemungu, 163 Seoulsiripdaero, Seoul, 02504, Republic of Korea
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18
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Abstract
Chlamydiae are bacterial pathogens that grow in vacuolar inclusions. Dendritic cells (DCs) disintegrate these compartments, thereby eliminating the microbes, through auto/xenophagy, which also promotes chlamydial antigen presentation via MHC I. Here, we show that TNF-α controls this pathway by driving cytosolic phospholipase (cPLA)2-mediated arachidonic acid (AA) production. AA then impairs mitochondrial function, which disturbs the development and integrity of these energy-dependent parasitic inclusions, while a simultaneous metabolic switch towards aerobic glycolysis promotes DC survival. Tubulin deacetylase/autophagy regulator HDAC6 associates with disintegrated inclusions, thereby further disrupting their subcellular localisation and stability. Bacterial remnants are decorated with defective mitochondria, mito-aggresomal structures, and components of the ubiquitin/autophagy machinery before they are degraded via mito-xenophagy. The mechanism depends on cytoprotective HSP25/27, the E3 ubiquitin ligase Parkin and HDAC6 and promotes chlamydial antigen generation for presentation on MHC I. We propose that this novel mito-xenophagic pathway linking innate and adaptive immunity is critical for effective DC-mediated anti-bacterial resistance.
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19
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Deficiency of RITA results in multiple mitotic defects by affecting microtubule dynamics. Oncogene 2016; 36:2146-2159. [DOI: 10.1038/onc.2016.372] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/08/2016] [Accepted: 08/28/2016] [Indexed: 01/31/2023]
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20
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Gu S, Liu Y, Zhu B, Ding K, Yao TP, Chen F, Zhan L, Xu P, Ehrlich M, Liang T, Lin X, Feng XH. Loss of α-Tubulin Acetylation Is Associated with TGF-β-induced Epithelial-Mesenchymal Transition. J Biol Chem 2016; 291:5396-405. [PMID: 26763233 DOI: 10.1074/jbc.m115.713123] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Indexed: 12/27/2022] Open
Abstract
The epithelial-to-mesenchymal transition (EMT) is a process by which differentiated epithelial cells reprogram gene expression, lose their junctions and polarity, reorganize their cytoskeleton, increase cell motility and assume a mesenchymal morphology. Despite the critical functions of the microtubule (MT) in cytoskeletal organization, how it participates in EMT induction and maintenance remains poorly understood. Here we report that acetylated α-tubulin, which plays an important role in microtubule (MT) stabilization and cell morphology, can serve as a novel regulator and marker of EMT. A high level of acetylated α-tubulin was correlated with epithelial morphology and it profoundly decreased during TGF-β-induced EMT. We found that TGF-β increased the activity of HDAC6, a major deacetylase of α-tubulin, without affecting its expression levels. Treatment with HDAC6 inhibitor tubacin or TGF-β type I receptor inhibitor SB431542 restored the level of acetylated α-tubulin and consequently blocked EMT. Our results demonstrate that acetylated α-tubulin can serve as a marker of EMT and that HDAC6 represents an important regulator during EMT process.
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Affiliation(s)
- Shuchen Gu
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yanjing Liu
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Bowen Zhu
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ke Ding
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Tso-Pang Yao
- Department of Pharmacology and Cancer Biology, Duke University Medical School, Durham, North Carolina 27710
| | - Fenfang Chen
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lixing Zhan
- Institute of Nutritional Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Pinglong Xu
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tingbo Liang
- Department of Hepatobiliary and Pancreatic Surgery and the Key Laboratory of Cancer Prevention and Intervention, The Second Affiliated Hospital, School of Medicine Zhejiang University, Hangzhou, Zhejiang 310009, China, and
| | - Xia Lin
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xin-Hua Feng
- From the Life Sciences Institute, and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China, Michael E. DeBakey Department of Surgery, and Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
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21
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Plácido AI, Pereira CMF, Correira SC, Carvalho C, Oliveira CR, Moreira PI. Phosphatase 2A Inhibition Affects Endoplasmic Reticulum and Mitochondria Homeostasis Via Cytoskeletal Alterations in Brain Endothelial Cells. Mol Neurobiol 2016; 54:154-168. [DOI: 10.1007/s12035-015-9640-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/15/2015] [Indexed: 12/30/2022]
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22
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Penazzi L, Bakota L, Brandt R. Microtubule Dynamics in Neuronal Development, Plasticity, and Neurodegeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 321:89-169. [PMID: 26811287 DOI: 10.1016/bs.ircmb.2015.09.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurons are the basic information-processing units of the nervous system. In fulfilling their task, they establish a structural polarity with an axon that can be over a meter long and dendrites with a complex arbor, which can harbor ten-thousands of spines. Microtubules and their associated proteins play important roles during the development of neuronal morphology, the plasticity of neurons, and neurodegenerative processes. They are dynamic structures, which can quickly adapt to changes in the environment and establish a structural scaffold with high local variations in composition and stability. This review presents a comprehensive overview about the role of microtubules and their dynamic behavior during the formation and maturation of processes and spines in the healthy brain, during aging and under neurodegenerative conditions. The review ends with a discussion of microtubule-targeted therapies as a perspective for the supportive treatment of neurodegenerative disorders.
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Affiliation(s)
- Lorène Penazzi
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
| | - Lidia Bakota
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
| | - Roland Brandt
- Department of Neurobiology, University of Osnabrück, Osnabrück, Germany
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23
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Li L, Yang XJ. Tubulin acetylation: responsible enzymes, biological functions and human diseases. Cell Mol Life Sci 2015; 72:4237-55. [PMID: 26227334 PMCID: PMC11113413 DOI: 10.1007/s00018-015-2000-5] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 12/28/2022]
Abstract
Microtubules have important functions ranging from maintenance of cell morphology to subcellular transport, cellular signaling, cell migration, and formation of cell polarity. At the organismal level, microtubules are crucial for various biological processes, such as viral entry, inflammation, immunity, learning and memory in mammals. Microtubules are subject to various covalent modifications. One such modification is tubulin acetylation, which is associated with stable microtubules and conserved from protists to humans. In the past three decades, this reversible modification has been studied extensively. In mammals, its level is mainly governed by opposing actions of α-tubulin acetyltransferase 1 (ATAT1) and histone deacetylase 6 (HDAC6). Knockout studies of the mouse enzymes have yielded new insights into biological functions of tubulin acetylation. Abnormal levels of this modification are linked to neurological disorders, cancer, heart diseases and other pathological conditions, thereby yielding important therapeutic implications. This review summarizes related studies and concludes that tubulin acetylation is important for regulating microtubule architecture and maintaining microtubule integrity. Together with detyrosination, glutamylation and other modifications, tubulin acetylation may form a unique 'language' to regulate microtubule structure and function.
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Affiliation(s)
- Lin Li
- Rosalind and Morris Goodman Cancer Research Center, Montreal, QC, H3A 1A3, Canada
- Department of Medicine, Montreal, QC, H3A 1A3, Canada
| | - Xiang-Jiao Yang
- Rosalind and Morris Goodman Cancer Research Center, Montreal, QC, H3A 1A3, Canada.
- Department of Medicine, Montreal, QC, H3A 1A3, Canada.
- Department of Biochemistry, McGill University, Montreal, QC, H3A 1A3, Canada.
- McGill University Health Center, Montreal, QC, H3A 1A3, Canada.
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24
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Lang UE, Cheung C, Vladar EK, Swetter SM, Kim J. Loss of primary cilia correlates with cytologic severity in dysplastic melanocytic nevi. J Cutan Pathol 2015; 43:113-9. [DOI: 10.1111/cup.12612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/11/2015] [Accepted: 08/11/2015] [Indexed: 12/15/2022]
Affiliation(s)
- Ursula E. Lang
- Section of Dermatopathology, Department of Dermatology and Pathology; Stanford University Medical Center; Stanford CA USA
| | - Christine Cheung
- Section of Dermatopathology, Department of Dermatology and Pathology; Stanford University Medical Center; Stanford CA USA
| | - Eszter K. Vladar
- Section of Dermatopathology, Department of Dermatology and Pathology; Stanford University Medical Center; Stanford CA USA
| | - Susan M. Swetter
- Department of Dermatology; Pigmented Lesion and Melanoma Program, Stanford University Medical Center; Stanford CA USA
- Dermatology Service; Veterans Affairs Palo Alto Health Care System; Palo Alto CA USA
| | - Jinah Kim
- Section of Dermatopathology, Department of Dermatology and Pathology; Stanford University Medical Center; Stanford CA USA
- Department of Dermatology; Pigmented Lesion and Melanoma Program, Stanford University Medical Center; Stanford CA USA
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25
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Kaul N, Soppina V, Verhey KJ. Effects of α-tubulin K40 acetylation and detyrosination on kinesin-1 motility in a purified system. Biophys J 2015; 106:2636-43. [PMID: 24940781 DOI: 10.1016/j.bpj.2014.05.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 11/28/2022] Open
Abstract
Long-range transport in cells is achieved primarily through motor-based transport along a network of microtubule tracks. Targeted transport by kinesin motors can be correlated with posttranslational modifications (PTMs) of the tubulin subunits in specific microtubules. To directly examine the influence of specific PTMs on kinesin-1 motility, we generated tubulin subunits that were either enriched in or lacking acetylation of α-tubulin lysine 40 (K40) or detyrosination of the α-tubulin C-terminal tail. We show that K40 acetylation does not result in significant changes in kinesin-1's landing rate or motility parameters (velocity and run length) across experimental conditions. In contrast, detyrosination causes a moderate increase in kinesin-1's landing rate. The fact that the effects of detyrosination are dampened by prior K40 acetylation indicates that the combination of PTMs may be an important aspect of the functional output of microtubule heterogeneity. Importantly, our results indicate that the moderate influences that single PTMs have on kinesin-1 in vitro do not explain the strong correlation between specific PTMs and kinesin-1 transport in cells. Thus, additional mechanisms for regulating kinesin-1 transport in cells must be explored in future work.
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Affiliation(s)
- Neha Kaul
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.
| | - Virupakshi Soppina
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
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26
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Abstract
Microtubules are cytoskeletal filaments that are dynamically assembled from α/β-tubulin heterodimers. The primary sequence and structure of the tubulin proteins and, consequently, the properties and architecture of microtubules are highly conserved in eukaryotes. Despite this conservation, tubulin is subject to heterogeneity that is generated in two ways: by the expression of different tubulin isotypes and by posttranslational modifications (PTMs). Identifying the mechanisms that generate and control tubulin heterogeneity and how this heterogeneity affects microtubule function are long-standing goals in the field. Recent work on tubulin PTMs has shed light on how these modifications could contribute to a “tubulin code” that coordinates the complex functions of microtubules in cells.
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Affiliation(s)
- Carsten Janke
- Institut Curie, 91405 Orsay, France Centre National de la Recherche Scientifique Unité Mixte de Recherche 3306, 91405 Orsay, France Institut National de la Santé et de la Recherche Médicale U1005, 91405 Orsay, France Paris Sciences et Lettres Research University, 75005 Paris, France
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27
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Jeganathan S, Fiorino C, Naik U, Sun HS, Harrison RE. Modulation of osteoclastogenesis with macrophage M1- and M2-inducing stimuli. PLoS One 2014; 9:e104498. [PMID: 25101660 PMCID: PMC4125219 DOI: 10.1371/journal.pone.0104498] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/14/2014] [Indexed: 12/15/2022] Open
Abstract
Macrophages are generated through the differentiation of monocytes in tissues and they have important functions in innate and adaptive immunity. In addition to their roles as phagocytes, macrophages can be further differentiated, in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF), into osteoclasts (multinucleated giant cells that are responsible for bone resorption). In this work, we set out to characterize whether various inflammatory stimuli, known to induce macrophage polarization, can alter the type of multinucleated giant cell obtained from RANKL differentiation. Following a four-day differentiation protocol, along with lipopolysaccharide (LPS)/interferon gamma (IFNγ) as one stimulus, and interleukin-4 (IL-4) as the other, three types of multinucleated cells were generated. Using various microscopy techniques (bright field, epifluorescence and scanning electron), functional assays, and western blotting for osteoclast markers, we found that, as expected, RANKL treatment alone resulted in osteoclasts, whereas the addition of LPS/IFNγ to RANKL pre-treated macrophages generated Langhans-type giant cells, while IL-4 led to giant cells resembling foreign body giant cells with osteoclast-like characteristics. Finally, to gain insight into the modulation of osteoclastogenesis, we characterized the formation and morphology of RANKL and LPS/IFNγ-induced multinucleated giant cells.
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Affiliation(s)
- Sujeeve Jeganathan
- Ontario Cancer Institute and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Cara Fiorino
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Urja Naik
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - He song Sun
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rene E. Harrison
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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Deakin NO, Turner CE. Paxillin inhibits HDAC6 to regulate microtubule acetylation, Golgi structure, and polarized migration. ACTA ACUST UNITED AC 2014; 206:395-413. [PMID: 25070956 PMCID: PMC4121979 DOI: 10.1083/jcb.201403039] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Polarized cell migration is essential for normal organism development and is also a critical component of cancer cell invasion and disease progression. Directional cell motility requires the coordination of dynamic cell-extracellular matrix interactions as well as repositioning of the Golgi apparatus, both of which can be controlled by the microtubule (MT) cytoskeleton. In this paper, we have identified a new and conserved role for the focal adhesion scaffold protein paxillin in regulating the posttranslational modification of the MT cytoskeleton through an inhibitory interaction with the α-tubulin deacetylase HDAC6. We also determined that through HDAC6-dependent regulation of the MT cytoskeleton, paxillin regulates both Golgi organelle integrity and polarized cell invasion and migration in both three-dimensional and two-dimensional matrix microenvironments. Importantly, these data reveal a fundamental role for paxillin in coordinating MT acetylation-dependent cell polarization and migration in both normal and transformed cells.
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Affiliation(s)
- Nicholas O Deakin
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Christopher E Turner
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
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29
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Trypanosoma cruzi bromodomain factor 3 binds acetylated α-tubulin and concentrates in the flagellum during metacyclogenesis. EUKARYOTIC CELL 2014; 13:822-31. [PMID: 24747213 DOI: 10.1128/ec.00341-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bromodomains are highly conserved acetyl-lysine binding domains found mainly in proteins associated with chromatin and nuclear acetyltransferases. The Trypanosoma cruzi genome encodes at least four bromodomain factors (TcBDFs). We describe here bromodomain factor 3 (TcBDF3), a bromodomain-containing protein localized in the cytoplasm. TcBDF3 cytolocalization was determined, using purified antibodies, by Western blot and immunofluorescence analyses in all life cycle stages of T. cruzi. In epimastigotes and amastigotes, it was detected in the cytoplasm, the flagellum, and the flagellar pocket, and in trypomastigotes only in the flagellum. Subcellular localization of TcBDF3 was also determined by digitonin extraction, ultrastructural immunocytochemistry, and expression of TcBDF3 fused to cyan fluorescent protein (CFP). Tubulin can acquire different posttranslational modifications, which modulate microtubule functions. Acetylated α-tubulin has been found in the axonemes of flagella and cilia, as well as in the subpellicular microtubules of trypanosomatids. TcBDF3 and acetylated α-tubulin partially colocalized in isolated cytoskeletons and flagella from T. cruzi epimastigotes and trypomastigotes. Interaction between the two proteins was confirmed by coimmunoprecipitation and far-Western blot assays with synthetic acetylated α-tubulin peptides and recombinant TcBDF3.
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30
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Li D, Gao J, Yang Y, Sun L, Suo S, Luo Y, Shui W, Zhou J, Liu M. CYLD coordinates with EB1 to regulate microtubule dynamics and cell migration. Cell Cycle 2014; 13:974-83. [PMID: 24552808 DOI: 10.4161/cc.27838] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cylindromatosis (CYLD), a deubiquitinase involved in inflammation and tumorigenesis via the modulation of cell signaling, has recently been identified as a critical regulator of microtubule dynamics. CYLD has also been shown to stimulate cell migration and thereby contribute to normal physiological processes. However, it remains elusive how the regulation of microtubule dynamic properties by CYLD is connected to its role in mediating cell migration. In this study, we performed yeast 2-hybrid screening with CYLD as bait and identified 7 CYLD-interacting proteins, including end-binding protein 1 (EB1). The CYLD-EB1 interaction was confirmed both in cells and in vitro, and these 2 proteins colocalized at the plus ends of microtubules. Interestingly, the association of CYLD with EB1 was significantly increased upon the stimulation of cell migration. CYLD coordinated with EB1 to orchestrate tail retraction, centrosome reorientation, and leading-edge microtubule stabilization in migratory cells. In addition, CYLD acted in concert with EB1 to regulate microtubule assembly in vitro, microtubule nucleation at the centrosome, and microtubule growth at the cell periphery. These data provide mechanistic insights into the actions of CYLD in the regulation of microtubule dynamics and cell migration. These findings also support the notion that coordinated actions of microtubule-binding proteins are critical for microtubule-mediated cellular events.
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Affiliation(s)
- Dengwen Li
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Jinmin Gao
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Yunfan Yang
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Lei Sun
- Tianjin Key Laboratory of Medical Epigenetics; School of Basic Medical Sciences; Tianjin Medical University; Tianjin, China
| | - Shaojun Suo
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Youguang Luo
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Wenqing Shui
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Jun Zhou
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Min Liu
- Tianjin Key Laboratory of Medical Epigenetics; School of Basic Medical Sciences; Tianjin Medical University; Tianjin, China
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Esteves AR, Gozes I, Cardoso SM. The rescue of microtubule-dependent traffic recovers mitochondrial function in Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2013; 1842:7-21. [PMID: 24120997 DOI: 10.1016/j.bbadis.2013.10.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/30/2013] [Accepted: 10/04/2013] [Indexed: 11/25/2022]
Abstract
In Parkinson's disease mitochondrial dysfunction can lead to a deficient ATP supply to microtubule protein motors leading to mitochondrial axonal transport disruption. Compromised axonal transport will then lead to a disorganized distribution of mitochondria and other organelles in the cell, as well as, the accumulation of aggregated proteins like alpha-synuclein. Moreover, axonal transport disruption can trigger synaptic accumulation of autophagosomes packed with damaged mitochondria and protein aggregates promoting synaptic failure. We previously observed that neuronal-like cells with an inherent mitochondrial impairment derived from PD patients contain a disorganized microtubule network, as well as, alpha-synuclein oligomer accumulation. In this work we provide new evidence that an agent that promotes microtubule network assembly, NAP (davunetide), improves microtubule-dependent traffic, restores the autophagic flux and potentiates autophagosome-lysosome fusion leading to autophagic vacuole clearance in Parkinson's disease cells. Moreover, NAP is capable of efficiently reducing alpha-synuclein oligomer content and its sequestration by the mitochondria. Most interestingly, NAP decreases mitochondrial ubiquitination levels, as well as, increases mitochondrial membrane potential indicating a rescue in mitochondrial function. Overall, we demonstrate that by improving microtubule-mediated traffic, we can avoid mitochondrial-induced damage and thus recover cell homeostasis. These results prove that NAP may be a promising therapeutic lead candidate for neurodegenerative diseases that involve axonal transport failure and mitochondrial impairment as hallmarks, like Parkinson's disease and related disorders.
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Affiliation(s)
- A R Esteves
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
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EB1, p150Glued, and Clasp1 control endothelial tubulogenesis through microtubule assembly, acetylation, and apical polarization. Blood 2013; 121:3521-30. [PMID: 23444400 DOI: 10.1182/blood-2012-11-470179] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Vascular tube morphogenesis requires the establishment of endothelial cell (EC) apical-basal polarity in three-dimensional (3D) extracellular matrices. To date, there is little understanding of how EC polarity is controlled during these highly dynamic and rapid morphogenic events. We show that the microtubule tip complex proteins, end binding 1 (EB1), p150(Glued), and Clasp1, control human EC tube formation by (1) inducing microtubule assembly and asymmetric cytoskeletal polarization, whereby acetylated and detyrosinated tubulins distribute in a subapical membrane location and filamentous actin distributes basally; (2) increasing tubulin posttranslational modifications, including required acetylation events; and (3) regulating an EC lumen signaling cascade that involves membrane type 1 matrix metallopatrinase (MT1-MMP)-dependent proteolysis as well as Pak, Raf, and Erk kinases. Another regulator of this process is the microtubule stabilizing protein, tau, which binds p150(Glued) and similarly affects EC lumen formation by controlling the levels of acetylated and detyrosinated tubulins. Increased expression of the tubulin deacetylases, sirtuin 2, and histone deacetylase 6 (HDAC6), blocks EC tube formation and cytoskeletal polarization, while siRNA suppression of these deacetylases stimulates these events. Overall, this work reveals a fundamental role for microtubule tip complex proteins in coordinating microtubule assembly, posttranslational modifications including acetylation, and apical-basal cytoskeletal polarization to control the developing apical membrane surface during blood vessel tubulogenesis in 3D matrix environments.
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Montopoli M, Bertin R, Chen Z, Bolcato J, Caparrotta L, Froldi G. Croton lechleri sap and isolated alkaloid taspine exhibit inhibition against human melanoma SK23 and colon cancer HT29 cell lines. JOURNAL OF ETHNOPHARMACOLOGY 2012; 144:747-753. [PMID: 23123266 DOI: 10.1016/j.jep.2012.10.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Croton lechleri Mull. Arg. (Euphorbiaceae) is a traditional medicinal plant which produces a red sap, traditionally known as "Sangre de Drago"; it is used in folk medicine externally for wounds, fractures, and haemorrhoids, internally for intestinal and stomach ulcers and also for the empirical cure of cancers. MATERIALS AND METHODS We investigated the effects of Croton lechleri sap and taspine in comparison with taxol and vinblastine on the growth of human cancer cell lines of SK23 (melanoma), LoVo and HT29 (colorectal cancer) using MTT and Trypan blue assays. Further, we studied cell cycle by flow cytometry and detected acetylated-α-tubulin by confocal microscope. RESULTS Croton lechleri inhibited cell proliferation starting from 1 μg/mL in SK23 cells, whereas 10 times higher concentrations were required for growth inhibition of HT-29 and LoVo cell lines. Also taspine (0.1 μg/mL) inhibited the SK23 and HT29 cell proliferation. Further, assay was assessed on SK23 and HT29 cell lines with 24-48 h treatment with sap and taspine. Both sap and taspine inhibited cancer cell proliferation; taspine showed higher activity on SK23 cells, which was significantly increased after 48 h of SK23 treatment. Using confocal microscopy we observed that Croton lechleri (1 μg/mL) caused a loss of microtubule structure, whereas taspine (0.5 μg/mL) caused an increase in acetylated α-tubulin and a modification of cellular morphology, mainly in SK23 cells. Croton lechleri sap 10 and 50 μg/mL influence cell cycle; 50 μg/mL sap caused a dramatic reduction of cells in G(1)/G(0) and S phases with a great increase of subG(0) cells. CONCLUSIONS The data showed that Croton lechleri and taspine could inhibit cell proliferation with higher potency against melanoma SK23 cells, supporting the empirical use of the sap as anticancer in ethnomedicine and taspine as a possible anticancer agent.
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Affiliation(s)
- Monica Montopoli
- Department of Pharmaceutical and Pharmacological Sciences, Padua University, Largo E. Meneghetti 2, Padua, Italy
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34
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Uzbekov RE, Maurel DB, Aveline PC, Pallu S, Benhamou CL, Rochefort GY. Centrosome fine ultrastructure of the osteocyte mechanosensitive primary cilium. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:1430-1441. [PMID: 23171702 DOI: 10.1017/s1431927612013281] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The centrosome is the principal microtubule organization center in cells, giving rise to microtubule-based organelles (e.g., cilia, flagella). The aim was to study the osteocyte centrosome morphology at an ultrastructural level in relation to its mechanosensitive function. Osteocyte centrosomes and cilia in tibial cortical bone were explored by acetylated alpha-tubulin (AαTub) immunostaining under confocal microscopy. For the first time, fine ultrastructure and spatial orientation of the osteocyte centrosome were explored by transmission electron microscopy on serial ultrathin sections. AαTub-positive staining was observed in 94% of the osteocytes examined (222/236). The mother centriole formed a short primary cilium and was longer than the daughter centriole due to an intermediate zone between centriole and cilium. The proximal end of the mother centriole was connected with the surface of daughter centriole by striated rootlets. The mother centriole exhibited distal appendages that interacted with the cell membrane and formed a particular structure called "cilium membrane prolongation." The primary cilium was mainly oriented perpendicular to the long axis of bone. Mother and daughter centrioles change their original mutual orientation during the osteocyte differentiation process. The short primary cilium is hypothesized as a novel type of fluid-sensing organelle in osteocytes.
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Affiliation(s)
- R E Uzbekov
- Department of Microscopy, François Rabelais University, Tours, France.
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35
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Lysine acetylation: elucidating the components of an emerging global signaling pathway in trypanosomes. J Biomed Biotechnol 2012; 2012:452934. [PMID: 23093844 PMCID: PMC3470893 DOI: 10.1155/2012/452934] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/20/2012] [Accepted: 07/30/2012] [Indexed: 12/31/2022] Open
Abstract
In the past ten years the number of acetylated proteins reported in literature grew exponentially. Several authors have proposed that acetylation might be a key component in most eukaryotic signaling pathways, as important as phosphorylation. The enzymes involved in this process are starting to emerge; acetyltransferases and deacetylases are found inside and outside the nuclear compartment and have different regulatory functions. In trypanosomatids several of these enzymes have been described and are postulated to be novel antiparasitic targets for the rational design of drugs. In this paper we overview the most important known acetylated proteins and the advances made in the identification of new acetylated proteins using high-resolution mass spectrometry. Also, we summarize what is known so far about the acetyltransferases and deacetylases in eukaryotes, focusing on trypanosomes and their potential use as chemotherapeutic targets.
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36
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Tubulin acetylation alone does not affect kinesin-1 velocity and run length in vitro. PLoS One 2012; 7:e42218. [PMID: 22870307 PMCID: PMC3411631 DOI: 10.1371/journal.pone.0042218] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/04/2012] [Indexed: 01/04/2023] Open
Abstract
Kinesin-1 plays a major role in anterograde transport of intracellular cargo along microtubules. Currently, there is an ongoing debate of whether α-tubulin K40 acetylation directly enhances the velocity of kinesin-1 and its affinity to the microtubule track. We compared motor motility on microtubules reconstituted from acetylated and deacetylated tubulin. For both, single- and multi-motor in vitro motility assays, we demonstrate that tubulin acetylation alone does not affect kinesin-1 velocity and run length.
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37
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Carney BK, Caruso Silva V, Cassimeris L. The microtubule cytoskeleton is required for a G2 cell cycle delay in cancer cells lacking stathmin and p53. Cytoskeleton (Hoboken) 2012; 69:278-89. [PMID: 22407961 DOI: 10.1002/cm.21024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 02/24/2012] [Accepted: 02/29/2012] [Indexed: 12/25/2022]
Abstract
In several cancer cell lines, depleting the microtubule (MT)-destabilizing protein stathmin/oncoprotein18 leads to a G2 cell cycle delay and apoptosis. These phenotypes are observed only in synergy with low levels of p53, but the pathway(s) activated by stathmin depletion to delay the cell cycle are unknown. We found that stathmin depletion caused greater MT stability in synergy with loss of p53, measured by the levels of acetylated α-tubulin and the rate of centrosomal MT nucleation. Nocodazole or vinblastine-induced MT depolymerization abrogated the stathmin-depletion induced G2 delay, measured by the percentage of cells staining positive for several markers (TPX2, CDK1 with inhibitory phosphorylation), indicating that MTs are required to lengthen G2. Live cell imaging showed that stathmin depletion increased time in G2 without an impact on the duration of mitosis, indicating that the longer interphase duration is not simply a consequence of a previous slowed mitosis. In contrast, stabilization of MTs with paclitaxel (8 nM) slowed mitosis without lengthening the duration of interphase, demonstrating that increased MT stability alone is not sufficient to delay cells in G2.
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Affiliation(s)
- Bruce K Carney
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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38
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Kim J, Dabiri S, Seeley ES. Primary cilium depletion typifies cutaneous melanoma in situ and malignant melanoma. PLoS One 2011; 6:e27410. [PMID: 22096570 PMCID: PMC3214062 DOI: 10.1371/journal.pone.0027410] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 10/17/2011] [Indexed: 12/14/2022] Open
Abstract
Cutaneous melanoma is a lethal malignancy that arises spontaneously or via in situ precursor neoplasms. While melanoma in situ and locally invasive malignant melanoma can be cured surgically, these lesions can sometimes be difficult to distinguish from melanocytic nevi. Thus, the identification of histolopathologic or molecular features that distinguish these biologically distinct lesions would represent an important advance. To this end, we determined the abundance of melanocytic primary cilia in a series of 62 cases composed of typical cutaneous melanocytic nevi, melanoma in situ, invasive melanoma, and metastatic melanoma. Primary cilia are sensory organelles that modulate developmental and adaptive signaling and notably, are substantially depleted from the neoplastic epithelium of pancreatic carcinoma at a stage equivalent to melanoma in situ. In this series, we find that while nearly all melanocytes in 22 melanocytic nevi possessed a primary cilium, a near-complete loss of this organelle was observed in 16 cases of melanoma in situ, in 16 unequivocal primary invasive melanomas, and in 8 metastatic tumors, each associated with a cutaneous primary lesion. These findings suggest that the primary cilium may be used to segregate cutaneous invasive melanoma and melanoma in situ from melanocytic nevi. Moreover, they place the loss of an organelle known to regulate oncogenic signaling at an early stage of melanoma development.
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Affiliation(s)
- Jinah Kim
- Department of Pathology, Stanford University Medical Center, Stanford, California, United States of America
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Akisaka T, Yoshida H, Takigawa T. Differential distribution of posttranslationally modified microtubules in osteoclasts. J Histochem Cytochem 2011; 59:630-8. [PMID: 21421796 DOI: 10.1369/0022155411405334] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The differential distribution of microtubules in osteoclasts in culture was examined by using antibodies against acetylated, tyrosinated, or detyrosinated tubulins. Tyrosinated tubulin was found throughout the cytoplasmic microtubules in all cells examined. An expanding protrusion that contained tyrosinated tubulin but none of the detyrosinated or acetylated form was seen in the immature osteoclasts. Detyrosinated or acetylated tubulin was detectable in the peripheral cytoplasm of the mature osteoclasts displaying the loss of the expanding protrusion. Although most of the microtubules were derived from the centrosome, noncentrosomal microtubules were distributed in the expanding protrusion, which was predominantly positive for tyrosinated tubulin. By tracing single microtubules, the authors found that their growing ends were always rich in tyrosinated tubulin subunits. End binding protein 1 bound preferentially to the microtubule ends. Both acetylated and tyrosinated microtubules were shown to be closely associated with podosomes. Microtubules appeared to grow over or into the podosomes; in addition, the growing ends of single microtubules could be observed to target the podosomes. Moreover, a microtubule-associated histone deacetylase 6 was localized in the podosomes of the osteoclast. On the basis of these results, the authors conclude that posttranslational modifications of microtubules may correlate with characteristic changes in podosome dynamics in osteoclasts.
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Affiliation(s)
- Toshitaka Akisaka
- Division of Oral Anatomy, Asahi University School of Dentistry, Mizuho, Gifu, Japan. mail:
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40
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Perdiz D, Mackeh R, Poüs C, Baillet A. The ins and outs of tubulin acetylation: more than just a post-translational modification? Cell Signal 2010; 23:763-71. [PMID: 20940043 DOI: 10.1016/j.cellsig.2010.10.014] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 10/01/2010] [Indexed: 11/17/2022]
Abstract
Microtubules are highly dynamic polymers of α/β tubulin heterodimers that play key roles in cell division and in organizing cell cytoplasm. Although they have been discovered more than two decades ago, tubulin post-translational modifications recently gained a new interest as their role was increasingly highlighted in neuron differentiation and neurodegenerative disorders. Here, we specifically focus on tubulin acetylation from its discovery to recent studies that provide new insights into how it is regulated in health and disease and how it impacts microtubule functions. Even though new mechanisms involving tubulin acetylation are regularly being uncovered, the molecular links between its location inside the microtubule lumen and its regulators and effectors is still poorly understood. This review highlights the emerging roles of tubulin acetylation in multiple cellular functions, ranging from cell motility, cell cycle progression or cell differentiation to intracellular trafficking and signalling. It also points out that tubulin acetylation should no longer be seen as a passive marker of microtubule stability, but as a broad regulator of microtubule functions.
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Affiliation(s)
- Daniel Perdiz
- Univ. Paris Sud-11, UPRES EA4530 IFR IPSIT, Faculté de Pharmacie, 5 rue JB Clément 92296 Châtenay-Malabry, France
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Fassett JT, Xu X, Hu X, Zhu G, French J, Chen Y, Bache RJ. Adenosine regulation of microtubule dynamics in cardiac hypertrophy. Am J Physiol Heart Circ Physiol 2009; 297:H523-32. [PMID: 19525375 DOI: 10.1152/ajpheart.00462.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is evidence that endogenous extracellular adenosine reduces cardiac hypertrophy and heart failure in mice subjected to chronic pressure overload, but the mechanism by which adenosine exerts these protective effects is unknown. Here, we identified a novel role for adenosine in regulation of the cardiac microtubule cytoskeleton that may contribute to its beneficial effects in the overloaded heart. In neonatal cardiomyocytes, phenylephrine promoted hypertrophy and reorganization of the cytoskeleton, which included accumulation of sarcomeric proteins, microtubules, and desmin. Treatment with adenosine or the stable adenosine analog 2-chloroadenosine, which decreased hypertrophy, specifically reduced accumulation of microtubules. In hypertrophied cardiomyocytes, 2-chloroadenosine or adenosine treatment preferentially targeted stabilized microtubules (containing detyrosinated alpha-tubulin). Consistent with a role for endogenous adenosine in reducing microtubule stability, levels of detyrosinated microtubules were elevated in hearts of CD73 knockout mice (deficient in extracellular adenosine production) compared with wild-type mice (195%, P < 0.05). In response to aortic banding, microtubules increased in hearts of wild-type mice; this increase was exaggerated in CD73 knockout mice, with significantly greater amounts of tubulin partitioning into the cold-stable Triton-insoluble fractions. The levels of this stable cytoskeletal fraction of tubulin correlated strongly with the degree of heart failure. In agreement with a role for microtubule stabilization in promoting cardiac dysfunction, colchicine treatment of aortic-banded mice reduced hypertrophy and improved cardiac function compared with saline-treated controls. These results indicate that microtubules contribute to cardiac dysfunction and identify, for the first time, a role for adenosine in regulating cardiomyocyte microtubule dynamics.
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Affiliation(s)
- John T Fassett
- Cardiovascular Division, Lillehei Heart Institute, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Chang J, Baloh RH, Milbrandt J. The NIMA-family kinase Nek3 regulates microtubule acetylation in neurons. J Cell Sci 2009; 122:2274-82. [PMID: 19509051 DOI: 10.1242/jcs.048975] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
NIMA-related kinases (Neks) belong to a large family of Ser/Thr kinases that have critical roles in coordinating microtubule dynamics during ciliogenesis and mitotic progression. The Nek kinases are also expressed in neurons, whose axonal projections are, similarly to cilia, microtubule-abundant structures that extend from the cell body. We therefore investigated whether Nek kinases have additional, non-mitotic roles in neurons. We found that Nek3 influences neuronal morphogenesis and polarity through effects on microtubules. Nek3 is expressed in the cytoplasm and axons of neurons and is phosphorylated at Thr475 located in the C-terminal PEST domain, which regulates its catalytic activity. Although exogenous expression of wild-type or phosphomimic (T475D) Nek3 in cultured neurons has no discernible impact, expression of a phospho-defective mutant (T475A) or PEST-truncated Nek3 leads to distorted neuronal morphology with disturbed polarity and deacetylation of microtubules via HDAC6 in its kinase-dependent manner. Thus, the phosphorylation at Thr475 serves as a regulatory switch that alters Nek3 function. The deacetylation of microtubules in neurons by unphosphorylated Nek3 raises the possibility that it could have a role in disorders where axonal degeneration is an important component.
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Affiliation(s)
- Jufang Chang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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Nicotinamide restores cognition in Alzheimer's disease transgenic mice via a mechanism involving sirtuin inhibition and selective reduction of Thr231-phosphotau. J Neurosci 2008; 28:11500-10. [PMID: 18987186 DOI: 10.1523/jneurosci.3203-08.2008] [Citation(s) in RCA: 265] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Memory loss is the signature feature of Alzheimer's disease, and therapies that prevent or delay its onset are urgently needed. Effective preventive strategies likely offer the greatest and most widespread benefits. Histone deacetylase (HDAC) inhibitors increase histone acetylation and enhance memory and synaptic plasticity. We evaluated the efficacy of nicotinamide, a competitive inhibitor of the sirtuins or class III NAD(+)-dependent HDACs in 3xTg-AD mice, and found that it restored cognitive deficits associated with pathology. Nicotinamide selectively reduces a specific phospho-species of tau (Thr231) that is associated with microtubule depolymerization, in a manner similar to inhibition of SirT1. Nicotinamide also dramatically increased acetylated alpha-tubulin, a primary substrate of SirT2, and MAP2c, both of which are linked to increased microtubule stability. Reduced phosphoThr231-tau was related to a reduction of monoubiquitin-conjugated tau, suggesting that this posttranslationally modified form of tau may be rapidly degraded. Overexpression of a Thr231-phospho-mimic tau in vitro increased clearance and decreased accumulation of tau compared with wild-type tau. These preclinical findings suggest that oral nicotinamide may represent a safe treatment for AD and other tauopathies, and that phosphorylation of tau at Thr231 may regulate tau stability.
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Alieva IB, Uzbekov RE. The centrosome is a polyfunctional multiprotein cell complex. BIOCHEMISTRY (MOSCOW) 2008; 73:626-43. [DOI: 10.1134/s0006297908060023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
In the past half century, beginning with electron microscopic studies of 9 + 2 motile and 9 + 0 primary cilia, novel insights have been obtained regarding the structure and function of mammalian cilia. All cilia can now be viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation. This view has had unanticipated consequences for our understanding of developmental processes and human disease.
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Affiliation(s)
- Peter Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
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Suzuki T, Inoue I, Yamagata T, Morita N, Furuichi T, Yamakawa K. Sequential expression of Efhc1/myoclonin1 in choroid plexus and ependymal cell cilia. Biochem Biophys Res Commun 2007; 367:226-33. [PMID: 18164683 DOI: 10.1016/j.bbrc.2007.12.126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 12/19/2007] [Indexed: 11/19/2022]
Abstract
EFHC1 is a gene mutated in patients with idiopathic epilepsies, and encodes the myoclonin1 protein. We here report the distribution of myoclonin1 in mouse. Immunohistochemical analyses revealed that the myoclonin1 first appeared at the roof of hindbrain at embryonic day 10 (E10), and moved on to choroid plexus at E14. At E18, it moved to ventricle walls and disappeared from choroid plexus. From neonatal to adult stages, myoclonin1 was concentrated in the cilia of ependymal cells at ventricle walls. At adult stages, myoclonin1 expression was also observed at tracheal epithelial cilia in lung and at sperm flagella in testis. Specificities of these immunohistochemical signals were verified by using Efhc1-deficient mice as negative controls. Results of Efhc1 mRNA in situ hybridization were also consistent with the immunohistochemical observations. Our findings raise "choroid plexusopathy" or "ciliopathy" as intriguing candidate cascades for the molecular pathology of epilepsies caused by the EFHC1 mutations.
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Affiliation(s)
- Toshimitsu Suzuki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
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Nahhas F, Dryden SC, Abrams J, Tainsky MA. Mutations in SIRT2 deacetylase which regulate enzymatic activity but not its interaction with HDAC6 and tubulin. Mol Cell Biochem 2007; 303:221-30. [PMID: 17516032 DOI: 10.1007/s11010-007-9478-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
Abstract
Human SIRT2 is a cytoplasmic NAD-dependent deacetylase implicated in the mitotic regulation of microtubule dynamics by its association with the class II histone deacetylase 6 (HDAC6). We have previously reported that SIRT2 is multiply phosphorylated in a cell cycle dependent pattern. Here, we demonstrate that HDAC6 binds to both phosphorylated and unphosphorylated forms of SIRT2 and that tubulin binds only to the SIRT2-HDAC6 complex. Tubulin does not bind to either HDAC6 or SIRT2 individually. In addition, we show that replacement of specific serines with alanines in either isoform of SIRT2 regulates its enzymatic activity. We also found that overexpression of isoform2 was deleterious to cell survival. SIRT2 was found to be phosphorylated at serines 368 and 372, outside the conserved core domain of the Sir2 protein family. Double replacement of S368A and S372A reduced SIRT2 deacetylase activity by 44% compared to wildtype activity. Replacements of other serine, threonine, and tyrosine residues, which did not alter the phosphorylation pattern, had varying effects on SIRT2 deacetylase activity but no effect on tubulin/HDAC6 binding.
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Affiliation(s)
- Fatimah Nahhas
- Program in Molecular Biology and Human Genetics, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Ikegami K, Mukai M, Tsuchida JI, Heier RL, MacGregor GR, Setou M. TTLL7 is a mammalian beta-tubulin polyglutamylase required for growth of MAP2-positive neurites. J Biol Chem 2006; 281:30707-16. [PMID: 16901895 PMCID: PMC3049811 DOI: 10.1074/jbc.m603984200] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Microtubules form a cytoskeletal framework that influences cell shape and provides structural support for the cell. Microtubules in the nervous system undergo a unique post-translational modification, polyglutamylation of the C termini of their tubulin subunits. The mammalian enzymes that perform beta-tubulin polyglutamylation as well as their physiological functions in the neuronal tissue remain elusive. We report identification of a mammalian polyglutamylase with specificity for beta-tubulin as well as its distribution and function in neurite growth. To identify putative tubulin polyglutamylases, we searched tubulin tyrosine ligase-like (TTLL) proteins for those predominantly expressed in the nervous system. Of 13 TTLL proteins, TTLL7 was transcribed at the highest level in the nervous system. Recombinant TTLL7 catalyzed tubulin polyglutamylation with high preference to beta-tubulin in vitro. When expressed in HEK293T cells, TTLL7 demonstrated specificity for beta-tubulin and not for alpha-tubulin or nucleosome assembly protein 1. Consistent with these findings, knockdown of TTLL7 in a primary culture of superior cervical ganglion neurons caused a loss of polyglutamylated beta-tubulin. Following stimulation of PC12 cells with nerve growth factor to differentiate, the level of TTLL7 increased concomitantly with polyglutamylation of beta-tubulin. Short interference RNA-mediated knockdown of TTLL7 repressed nerve growth factor-stimulated MAP (microtubule-associated protein) 2-positive neurite growth in PC12 cells. Consistent with having a role in the growth of MAP2-positive neurites, TTLL7 accumulated within a MAP2-enriched somatodendritic portion of superior cervical ganglion, as did polyglutamylated beta-tubulin. Anti-TTLL7 antibody revealed that TTLL7 was distributed in a somatodendritic compartment in the mouse brain. These findings indicate that TTLL7 is a beta-tubulin polyglutamylase and is required for the growth of MAP2-positive neurites in PC12 cells.
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Affiliation(s)
- Koji Ikegami
- Mitsubishi Kagaku Institute of Life Sciences, Minamiooya, Machida, Tokyo 194-8511, Japan
| | - Masahiro Mukai
- Mitsubishi Kagaku Institute of Life Sciences, Minamiooya, Machida, Tokyo 194-8511, Japan
| | - Jun-ichi Tsuchida
- Mitsubishi Pharma Corporation, 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa 227-0033, Japan
| | - Robb L. Heier
- Department of Developmental and Cell Biology, Developmental Biology Center, and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, California 92697-3940
| | - Grant R. MacGregor
- Department of Developmental and Cell Biology, Developmental Biology Center, and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, California 92697-3940
| | - Mitsutoshi Setou
- Mitsubishi Kagaku Institute of Life Sciences, Minamiooya, Machida, Tokyo 194-8511, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama, Japan
- National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
- To whom correspondence should be addressed: National Institute for Physiological Science, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan. Tel.: 81-42-724-6259; Fax: 81-42-724-6341;
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Affiliation(s)
- H T Idriss
- Structural Biology Group, School of Biomedical Sciences, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland, United Kingdom.
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MacRae TH. Tubulin post-translational modifications--enzymes and their mechanisms of action. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 244:265-78. [PMID: 9118990 DOI: 10.1111/j.1432-1033.1997.00265.x] [Citation(s) in RCA: 232] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This review describes the enzymes responsible for the post-translational modifications of tubulin, including detyrosination/tyrosination, acetylation/deacetylation, phosphorylation, polyglutamylation, polyglycylation and the generation of non-tyrosinatable alpha-tubulin. Tubulin tyrosine-ligase, which reattaches tyrosine to detyrosinated tubulin, has been extensively characterized and its gene sequenced. Enzymes such as tubulin-specific carboxypeptidase and alpha-tubulin acetyltransferase, required, respectively, for detyrosination and acetylation of tubulin, have yet to be purified to homogeneity and examined in defined systems. This has produced some conflicting results, especially for the carboxypeptidase. The phosphorylation of tubulin by several different types of kinases has been studied in detail but drawing conclusions is difficult because many of these enzymes modify proteins other than their actual substrates, an especially pertinent consideration for in vitro experiments. Tubulin phosphorylation in cultured neuronal cells has proven to be the best model for evaluation of kinase effects on tubulin/microtubule function. There is little information on the enzymes required for polyglutamylation, polyglycylation, and production of non-tyrosinatable tubulin, but the available data permit interesting speculation of a mechanistic nature. Clearly, to achieve a full appreciation of tubulin post-translational changes the responsible enzymes must be characterized. Knowing when the enzymes are active in cells, if soluble or polymerized tubulin is the preferred substrate and the amino acid residues modified by each enzyme are all important. Moreover, acquisition of purified enzymes will lead to cloning and sequencing of their genes. With this information, one can manipulate cell genomes in order to either modify key enzymes or change their relative amounts, and perhaps reveal the physiological significance of tubulin post-translational modifications.
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Affiliation(s)
- T H MacRae
- Department of Biology, Dalhousie University, Halifax, Canada
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