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Schmidt-Marcec S, Ross A, Smertenko A. Quantification of Microtubule-Bundling Activity of MAPs Using TIRF Microscopy. Methods Mol Biol 2023; 2604:1-12. [PMID: 36773221 DOI: 10.1007/978-1-0716-2867-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Cross-linking of microtubules by microtubule-associated proteins (MAPs) results in the formation of microtubule bundles. It has been shown that a majority of microtubules in interphase plant cells are bundled. Bundling can contribute to maintaining structural stability and sustaining spatial organization of microtubule arrays. While bundling can be readily detected by an electron or fluorescent microscope, quantifying this activity remains technically challenging. Here we describe a method for quantifying microtubule-bundling in vitro using green and red stable microtubules. Furthermore, this method distinguishes between different types of microtubule-microtubule interactions: bundling, annealing, and branching. Our technique can be used to compare bundling activity of different MAPs and generate parameters for modeling their contribution to organization and dynamics of microtubule arrays.
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Affiliation(s)
| | - Austin Ross
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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2
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Tanaka MT, Tanji K, Miki Y, Ozaki T, Mori F, Hayashi H, Kakita A, Wakabayashi K. Phosphorylation of Tau at Threonine 231 in Patients With Multiple System Atrophy and in a Mouse Model. J Neuropathol Exp Neurol 2022; 81:920-930. [PMID: 36083205 DOI: 10.1093/jnen/nlac082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder pathologically characterized by the presence of glial cytoplasmic inclusions (GCIs). Some MSA patients exhibit motor deficits with accompanying cognitive impairment. Of note, some patients suffering from MSA with longer disease duration have AT8-positive signals, which correspond to phosphorylated tau (P-tau) at 202/205 (P-tau202/205). However, P-tau sites other than the AT8 antibody epitope antibody are less well studied. Here, we focused on the effect of α-synuclein (Syn) expression on the phosphorylation of tau in MSA model mice. Among the 6 kinds of antibodies against P-tau, we confirmed that antibodies against P-tau at 231 (P-tau231) were phospho-specific and found that P-tau231 level was increased in parallel with disease progression in MSA model mice. Additional studies of human brains revealed that P-tau231 was mainly expressed in the temporal cortex in MSA brains and that its expression level was significantly higher in MSA patients than in controls. Immunohistochemical analysis showed that anti-P-tau231-, but not AT8, antibodies mainly immunolabeled hippocampal CA2/3 pyramidal neurons, and some GCIs in MSA. These data suggest that P-tau231 occurs in MSA differently from P-tau202/205.
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Affiliation(s)
- Makoto T Tanaka
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Department of Biological Science, Graduate School of Science and Engineering, Iwate University, Morioka, Japan
| | - Kunikazu Tanji
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yasuo Miki
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Taku Ozaki
- Department of Biological Science, Graduate School of Science and Engineering, Iwate University, Morioka, Japan
| | - Fumiaki Mori
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hideki Hayashi
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Koichi Wakabayashi
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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3
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Muthu SJ, Lakshmanan G, Shimray KW, Kaliyappan K, Sathyanathan SB, Seppan P. Testosterone Influence on Microtubule-Associated Proteins and Spine Density in Hippocampus: Implications on Learning and Memory. Dev Neurosci 2022; 44:498-507. [PMID: 35609517 DOI: 10.1159/000525038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/26/2022] [Indexed: 11/19/2022] Open
Abstract
The thorny protrusions or spines increase the neuronal surface area, facilitate synaptic interconnections among neurons, and play an essential role in the hippocampus. Increasing evidence suggests that testosterone, the gonadal hormone, plays an important role in neurogenesis and synaptic plasticity. The role of testosterone on microtubule-associated proteins on dendritic neurite stability in the hippocampus and its impact on learning disability is not elucidated. Adult male Wistar albino rats were randomly selected for the control, castrated, castrated + testosterone, and control + testosterone groups. Bilateral orchidectomy was done, and the testosterone propionate was administered during the entire trial period, i.e., 14 days. The learning assessments were done using working/reference memory versions of the 8-arm radial maze and hippocampal tissues processed for histological and protein expressions. There were reduced expressions of microtubule-associated protein 2 (MAP2), postsynaptic density protein 95 (PSD95), and androgen receptor (AR) and increased expression of pTau in the castrated group. Conversely, the expression of MAP2, PSD95, and AR was increased, and the pTau expression was reduced in the hippocampus of the castrated rat administrated with testosterone. Androgen-depleted rats showed impaired synaptic plasticity in the hippocampus associated with contracted microtubule dynamics. Along with learning disability, there was an increased number of reference memory errors and working memory errors in castrated rats. Observations suggest that androgen regulates expression of neural tissue-specific MAPs and plays a vital role in hippocampus synaptic plasticity and that a similar mechanism may underlie neurological disorders in aging and hypogonadal men.
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Affiliation(s)
- Sakthi Jothi Muthu
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Ganesh Lakshmanan
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Khayinmi Wungpam Shimray
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Kathiravan Kaliyappan
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | | | - Prakash Seppan
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
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4
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Rafiei A, Schriemer DC. A Crosslinking Mass Spectrometry Protocol for the Structural Analysis of Microtubule-Associated Proteins. Methods Mol Biol 2022; 2456:211-222. [PMID: 35612744 DOI: 10.1007/978-1-0716-2124-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Microtubule-associated proteins (MAPs) engage microtubules (MTs) to regulate both the MT state and wide variety of cytoskeletal functions. A comprehensive understanding of MAPs function requires the structural characterization of physical contacts MAPs make with other proteins, particularly when engaged with the microtubule (MT) lattice. Most of the interaction between MAPs and MTs evade classical structural determination techniques, as the interactions can be both heterogenous and sub-stoichiometric. Crosslinking mass spectrometry (XL-MS) can aid in MAP-MT structure analysis by providing a wealth of residue-based distance restraints. This protocol provides an XL-MS workflow for accurate and unbiased sampling of an equilibrated MAP-MT interaction, involving modifications to the preparation and validation of a MAP-MT construct suitable for crosslinking with fast-sampling heterobifunctional crosslinkers. The distance restrains obtained by this protocol can be used to generate accurate models assembled with an integrative structural modeling approach.
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Affiliation(s)
- Atefeh Rafiei
- Department of Chemistry, University of Calgary, Calgary, AB, Canada
| | - David C Schriemer
- Department of Chemistry, University of Calgary, Calgary, AB, Canada.
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada.
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5
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Ho-Pl�garo T, Huertas R, Tamayo-Navarrete MI, Blancaflor E, Gavara N, Garc�a-Garrido JM. A Novel Putative Microtubule-Associated Protein Is Involved in Arbuscule Development during Arbuscular Mycorrhiza Formation. Plant Cell Physiol 2021; 62:306-320. [PMID: 33386853 PMCID: PMC8112838 DOI: 10.1093/pcp/pcaa159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/06/2020] [Indexed: 05/11/2023]
Abstract
The formation of arbuscular mycorrhizal (AM) symbiosis requires plant root host cells to undergo major structural and functional reprogramming to house the highly branched AM fungal structure for the reciprocal exchange of nutrients. These morphological modifications are associated with cytoskeleton remodelling. However, molecular bases and the role of microtubules (MTs) and actin filament dynamics during AM formation are largely unknown. In this study, the tomato tsb (tomato similar to SB401) gene, belonging to a Solanaceae group of genes encoding MT-associated proteins (MAPs) for pollen development, was found to be highly expressed in root cells containing arbuscules. At earlier stages of mycorrhizal development, tsb overexpression enhanced the formation of highly developed and transcriptionally active arbuscules, while tsb silencing hampers the formation of mature arbuscules and represses arbuscule functionality. However, at later stages of mycorrhizal colonization, tsb overexpressing (OE) roots accumulate fully developed transcriptionally inactive arbuscules, suggesting that the collapse and turnover of arbuscules might be impaired by TSB accumulation. Imaging analysis of the MT cytoskeleton in cortex root cells OE tsb revealed that TSB is involved in MT bundling. Taken together, our results provide unprecedented insights into the role of novel MAP in MT rearrangements throughout the different stages of the arbuscule life cycle.
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Affiliation(s)
- Tania Ho-Pl�garo
- Department of Soil Microbiology and Symbiotic Systems, Estaci�n Experimental del Zaid�n (EEZ), CSIC, Calle Profesor Albareda No 1, Granada 18008, Spain
| | - Ra�l Huertas
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Mar�a I Tamayo-Navarrete
- Department of Soil Microbiology and Symbiotic Systems, Estaci�n Experimental del Zaid�n (EEZ), CSIC, Calle Profesor Albareda No 1, Granada 18008, Spain
| | - Elison Blancaflor
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Nuria Gavara
- Unitat de Biof�sica i Bioenginyeria, Facultat de Medicina i Ci�ncies de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Jos� M Garc�a-Garrido
- Department of Soil Microbiology and Symbiotic Systems, Estaci�n Experimental del Zaid�n (EEZ), CSIC, Calle Profesor Albareda No 1, Granada 18008, Spain
- Corresponding author: E-mail, ; Fax, +34-958181609
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6
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Nosala C, Hagen KD, Hilton N, Chase TM, Jones K, Loudermilk R, Nguyen K, Dawson SC. Disc-associated proteins mediate the unusual hyperstability of the ventral disc in Giardia lamblia. J Cell Sci 2020; 133:jcs.227355. [PMID: 32661087 DOI: 10.1242/jcs.227355] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 06/29/2020] [Indexed: 12/26/2022] Open
Abstract
Giardia lamblia, a widespread parasitic protozoan, attaches to the host gastrointestinal epithelium by using the ventral disc, a complex microtubule (MT) organelle. The 'cup-like' disc is formed by a spiral MT array that scaffolds numerous disc-associated proteins (DAPs) and higher-order protein complexes. In interphase, the disc is hyperstable and has limited MT dynamics; however, it remains unclear how DAPs confer these properties. To investigate mechanisms of hyperstability, we confirmed the disc-specific localization of over 50 new DAPs identified by using both a disc proteome and an ongoing GFP localization screen. DAPs localize to specific disc regions and many lack similarity to known proteins. By screening 14 CRISPRi-mediated DAP knockdown (KD) strains for defects in hyperstability and MT dynamics, we identified two strains - DAP5188KD and DAP6751KD -with discs that dissociate following high-salt fractionation. Discs in the DAP5188KD strain were also sensitive to treatment with the MT-polymerization inhibitor nocodazole. Thus, we confirm here that at least two of the 87 known DAPs confer hyperstable properties to the disc MTs, and we anticipate that other DAPs contribute to disc MT stability, nucleation and assembly.
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Affiliation(s)
- Christopher Nosala
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kari D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Nicholas Hilton
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Tiffany M Chase
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kelci Jones
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Rita Loudermilk
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kristofer Nguyen
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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7
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Abstract
The cytoskeleton consists of polymeric protein filaments with periodic lattices displaying identical binding sites, which establish a multivalent platform for the binding of a plethora of filament-associated ligand proteins. Multivalent ligand proteins can tether themselves to the filaments through one of their binding sites, resulting in an enhanced reaction kinetics for the remaining binding sites. In this Opinion, we discuss a number of cytoskeletal phenomena underpinned by such multivalent interactions, namely (1) generation of entropic forces by filament crosslinkers, (2) processivity of molecular motors, (3) spatial sorting of proteins, and (4) concentration-dependent unbinding of filament-associated proteins. These examples highlight that cytoskeletal filaments constitute the basis for the formation of microenvironments, which cytoskeletal ligand proteins can associate with and, once engaged, can act within at altered reaction kinetics. We thus argue that multivalency is one of the properties crucial for the functionality of the cytoskeleton.
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Affiliation(s)
- Marcus Braun
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, 25250 Vestec, Prague West, Czech Republic
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden 01307, Germany .,Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden 01307, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
| | - Zdenek Lansky
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, 25250 Vestec, Prague West, Czech Republic
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8
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Song Y, Zhang Y, Pan Y, He J, Wang Y, Chen W, Guo J, Deng H, Xue Y, Fang X, Liang X. The microtubule end-binding affinity of EB1 is enhanced by a dimeric organization that is susceptible to phosphorylation. J Cell Sci 2020; 133:jcs241216. [PMID: 32152183 DOI: 10.1242/jcs.241216] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/28/2020] [Indexed: 12/18/2022] Open
Abstract
In cells, microtubule dynamics are regulated by plus-end tracking proteins (+TIPs). End-binding protein 1 (EB1, also known as MAPRE1) acts as a master regulator of +TIP networks by targeting the growing ends of microtubules and recruiting other factors. However, the molecular mechanism underlying high-affinity binding of EB1 to microtubule ends remains an open area of research. Using single-molecule imaging, we show that the end-binding kinetics of EB1 change when the polymerization and hydrolysis rates of tubulin dimers are altered, confirming that EB1 binds to GTP-tubulin and/or GDP-Pi-tubulin at microtubule growing ends. The affinity of wild-type EB1 to these sites is higher than that of monomeric EB1 mutants, suggesting that both calponin homology domains present in the EB1 dimer contribute to end binding. Introduction of phosphomimetic mutations into the EB1 linker domain weakens the end-binding affinity and confers a more curved conformation on the EB1 dimer without compromising dimerization, suggesting that the overall architecture of EB1 is important for its end-binding affinity. Taken together, our results provide insights into how the high-affinity end-binding of EB1 is achieved and how this activity may be regulated in cells.
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Affiliation(s)
- Yinlong Song
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Yikan Zhang
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Ying Pan
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jianfeng He
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Yan Wang
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Wei Chen
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jing Guo
- Protein Chemistry Facility at the Center for Biomedical Analysis of Tsinghua University, 100084 Beijing, China
| | - Haiteng Deng
- Protein Chemistry Facility at the Center for Biomedical Analysis of Tsinghua University, 100084 Beijing, China
| | - Yi Xue
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xianyang Fang
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xin Liang
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
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Hromadkova L, Bezdekova D, Pala J, Schedin-Weiss S, Tjernberg LO, Hoschl C, Ovsepian SV. Brain-derived neurotrophic factor (BDNF) promotes molecular polarization and differentiation of immature neuroblastoma cells into definitive neurons. Biochim Biophys Acta Mol Cell Res 2020; 1867:118737. [PMID: 32389647 DOI: 10.1016/j.bbamcr.2020.118737] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 04/27/2020] [Accepted: 05/03/2020] [Indexed: 12/21/2022]
Abstract
Throughout development, neuronal progenitors undergo complex transformation into polarized nerve cells, warranting the directional flow of information in the neural grid. The majority of neuronal polarization studies have been carried out on rodent-derived precursor cells, programmed to develop into neurons. Unlike rodent neuronal cells, SH-SY5Y cells derived from human bone marrow present a sub-clone of neuroblastoma line, with their transformation into neuron-like cells showing a range of highly instructive neurobiological characteristics. We applied two-step retinoic acid (RA) and brain-derived neurotrophic factor (BDNF) protocol to monitor the conversion of undifferentiated SH-SY5Y into neuron-like cells with distinctly polarized axon-dendritic morphology and formation of bona fide synaptic connections. We show that BDNF is a key driver and regulator of the expression of axonal marker tau and dendritic microtubule-associated protein-2 (MAP2), with their sorting to distinct cellular compartments. Using selective kinase inhibitors downregulating BDNF-TrkB signaling, we demonstrate that constitutive activation of TrkB receptor is essential for the maintenance of established polarization morphology. Importantly, the proximity ligation assay applied in our preparation demonstrates that differentiating neuron-like cells develop elaborate synaptic connections enriched with hallmark pre- and postsynaptic proteins. Described herein findings highlight several fundamental processes related to neuronal polarization and synaptogenesis in human-derived cells, which are of major relevance to neurobiology and translational neuroscience.
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10
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Fouani L, Huang MLH, Cole L, Jansson PJ, Kovacevic Z, Richardson DR. During mitosis ZEB1 "switches" from being a chromatin-bound epithelial gene repressor, to become a microtubule-associated protein. Biochim Biophys Acta Mol Cell Res 2020; 1867:118673. [PMID: 32057919 DOI: 10.1016/j.bbamcr.2020.118673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/30/2020] [Accepted: 02/02/2020] [Indexed: 12/23/2022]
Abstract
Microtubules are polymers of α/β-tubulin, with microtubule organization being regulated by microtubule-associated proteins (MAPs). Herein, we describe a novel role for the epithelial gene repressor, zinc finger E-box-binding homeobox 1 (ZEB1), that "switches" from a chromatin-associated protein during interphase, to a MAP that associates with α-, β- and γ-tubulin during mitosis. Additionally, ZEB1 was also demonstrated to associate with γ-tubulin at the microtubule organizing center (MTOC). Using confocal microscopy, ZEB1 localization was predominantly nuclear during interphase, with α/β-tubulin being primarily cytoplasmic and the association between these proteins being minimal. However, during the stages of mitosis, ZEB1 co-localization with α-, β-, and γ-tubulin was significantly increased, with the association commonly peaking during metaphase in multiple tumor cell-types. ZEB1 was also observed to accumulate in the cleavage furrow during cytokinesis. The increased interaction between ZEB1 and α-tubulin during mitosis was also confirmed using the proximity ligation assay. In contrast to ZEB1, its paralog ZEB2, was mainly perinuclear and cytoplasmic during interphase, showing some co-localization with α-tubulin during mitosis. Considering the association between ZEB1 with α/β/γ-tubulin during mitosis, studies investigated ZEB1's role in the cell cycle. Silencing ZEB1 resulted in a G2-M arrest, which could be mediated by the up-regulation of p21Waf1/Cip1 and p27Kip1 that are known downstream targets repressed by ZEB1. However, it cannot be excluded the G2/M arrest observed after ZEB1 silencing is not due to its roles as a MAP. Collectively, ZEB1 plays a role as a MAP during mitosis and could be functionally involved in this process.
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11
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Wang C, Zhang H, Xia Q, Yu J, Zhu D, Zhao Q. ZmGLR, a cell membrane localized microtubule-associated protein, mediated leaf morphogenesis in maize. Plant Sci 2019; 289:110248. [PMID: 31623783 DOI: 10.1016/j.plantsci.2019.110248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
Microtubule arrays play notable roles in cell division, cell movement, cell morphogenesis and signal transduction. Due to their important regulation of microtubule dynamic instability and array-ordering processes, microtubule-associated proteins have been a cutting-edge issue in research. Here, a new maize microtubule-associated protein, ZmGLR (Zea mays glutamic acid- and lysine-rich), was found. ZmGLR bundles microtubules in vitro and targets the cell membrane through an interaction between 24 conserved N-terminal amino acids and specific phosphatidylinositol phosphates (PtdInsPs). Increased Ca2+ levels in the cytoplasm lead to ZmGLR partially dissociating from the cell membrane and moving into the cytoplasm to associate with microtubule. Overexpression and RNAi of ZmGLR both resulted in misoriented microtubule arrays, which led to dwarf maize plants and curved leaves. In addition, the expression of ZmGLR was regulated by BR and auxin through ZmBES1 and ZmARF9, respectively. This study reveals that the microtubule-associated protein ZmGLR plays a crucial role in cortical microtubule reorientation and maize leaf morphogenesis.
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Affiliation(s)
- Chenchen Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Hua Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Qi Xia
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jingjuan Yu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Dengyun Zhu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Qian Zhao
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.
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12
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Abstract
Microtubules in the mitotic spindle are organised by microtubule-associated proteins. In the late stage of mitosis, spindle microtubules are robustly organised through bundling by the antiparallel microtubule bundler Ase1/PRC1. In early mitosis, however, it is not well characterised as to whether spindle microtubules are actively bundled, as Ase1 does not particularly localise to the spindle at that stage. Here we show that the conserved microtubule-associated protein CLASP (fission yeast Peg1/Cls1) facilitates bundling of spindle microtubules in early mitosis. The peg1 mutant displayed a fragile spindle with unbundled microtubules, which eventually resulted in collapse of the metaphase spindle and abnormal segregation of chromosomes. Peg1 is known to be recruited to the spindle by Ase1 to stabilise antiparallel microtubules in late mitosis. However, we demonstrate that the function of Peg1 in early mitosis does not rely on Ase1. The unbundled spindle phenotype of the peg1 mutant was not seen in the ase1 mutant, and Peg1 preferentially localised to the spindle even in early mitosis unlike Ase1. Moreover, artificial overexpression of Ase1 in the peg1 mutant partially suppressed unbundled microtubules. We thus conclude that Peg1 bundles microtubules in early mitosis, in a distinct manner from its conventional Ase1-dependent functions in other cell cycle stages.
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Affiliation(s)
- Hirohisa Ebina
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Liang Ji
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan.,Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masamitsu Sato
- Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan .,Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Institute for Medical-Oriented Structural Biology Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan.,Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480, Japan
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13
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Rodrigues-Ferreira S, Molina A, Nahmias C. Microtubule-associated tumor suppressors as prognostic biomarkers in breast cancer. Breast Cancer Res Treat 2019; 179:267-273. [PMID: 31606824 DOI: 10.1007/s10549-019-05463-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE Breast cancer is the most common malignancy in women worldwide. Although important therapeutic progress was achieved over the past decade, this disease remains a public health problem. In light of precision medicine, the identification of new prognostic biomarkers in breast cancer is urgently needed to stratify populations of patients with poor clinical outcome who may benefit from new personalized therapies. The microtubule cytoskeleton plays a pivotal role in essential cellular functions and is an interesting target for cancer therapy. Microtubule assembly and dynamics are regulated by a wide range of microtubule-associated proteins (MAPs), some of which have oncogenic or tumor suppressor effects in breast cancer. RESULTS This review covers current knowledge on microtubule-associated tumor suppressors (MATS) in breast cancer and their potential value as prognostic biomarkers. We present recent studies showing that combinatorial expression of ATIP3 and EB1, two microtubule-associated biomarkers with tumor suppressor and oncogenic effects, respectively, improves breast cancer prognosis compared to each biomarker alone. CONCLUSIONS These findings are discussed regarding the increasing complexity of protein networks composed of MAPs that coordinate microtubule dynamics and functions. Further studies are warranted to evaluate the prognostic value of combined expression of different MATS and their interacting partners in breast cancer.
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Affiliation(s)
- Sylvie Rodrigues-Ferreira
- INSERM U981, LabEx LERMIT, Gustave Roussy Cancer Center, Department of Molecular Medicine, Université Paris Sud, 94800, Villejuif, France.,Inovarion, 75014, Paris, France
| | - Angie Molina
- INSERM U981, LabEx LERMIT, Gustave Roussy Cancer Center, Department of Molecular Medicine, Université Paris Sud, 94800, Villejuif, France.,Centre de Biologie du Développement, Centre de Biologie Intégrative, UMR 5547 CNRS/Université Paul Sabatier, 31400, Toulouse, France
| | - Clara Nahmias
- INSERM U981, LabEx LERMIT, Gustave Roussy Cancer Center, Department of Molecular Medicine, Université Paris Sud, 94800, Villejuif, France. .,Inserm U981, Gustave Roussy Cancer Center, 114 rue Edouard Vaillant, 94800, Villejuif, France.
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14
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Ma H, Liu M. The microtubule cytoskeleton acts as a sensor for stress response signaling in plants. Mol Biol Rep 2019; 46:5603-5608. [PMID: 31098806 DOI: 10.1007/s11033-019-04872-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/13/2019] [Indexed: 01/17/2023]
Abstract
Stress tolerance pathways are protective mechanisms that have evolved to protect plant growth and increase production under various environmental stress conditions. Enhancing stress tolerance in crop plants has become an area of intense study with aims of increasing crop production and enhancing economic benefits. A growing number of studies suggest that in addition to playing vital roles in mechanical architecture and cell division, microtubules are also involved the adaptation to severe environmental conditions in plants. However, the mechanisms that integrate microtubule regulation, cellular metabolism and cell signaling in plant stress responses remain unclear. Recent studies suggest that microtubules act as sensors for different abiotic stresses and maintain mechanical stability by forming bundles. Characterizing the diverse roles of plant microtubules is vital to furthering our understanding of stress tolerance in plants.
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Affiliation(s)
- Huixian Ma
- College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Min Liu
- College of Life Sciences, Shandong Normal University, Jinan, 250014, China.
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15
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Zhu Y, Tan W, Lee WL. An in vitro Microscopy-based Assay for Microtubule-binding and Microtubule-crosslinking by Budding Yeast Microtubule-associated Protein. Bio Protoc 2018; 8:e3110. [PMID: 30733975 DOI: 10.21769/bioprotoc.3110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In this protocol, we describe a simple microscopy-based method to assess the interaction of a microtubule-associated protein (MAP) with microtubules. The interaction between MAP and microtubules is typically assessed by a co-sedimentation assay, which measures the amount of MAP that co-pellets with microtubules by centrifugation, followed by SDS-PAGE analysis of the supernatant and pellet fractions. However, MAPs that form large oligomers tend to pellet on their own during the centrifugation step, making it difficult to assess co-sedimentation. Here we describe a microscopy-based assay that measures microtubule binding by direct visualization using fluorescently-labeled MAP, solving the limitations of the co-sedimentation assay. Additionally, we recently reported quantification of microtubule bundling by measuring the thickness of individual microtubule structures observed in the microscopy-based assay, making the protocol more advantageous than the traditional microtubule co-pelleting assay.
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Affiliation(s)
- Yili Zhu
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Weimin Tan
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Wei-Lih Lee
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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16
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Sébastien M, Giannesini B, Aubin P, Brocard J, Chivet M, Pietrangelo L, Boncompagni S, Bosc C, Brocard J, Rendu J, Gory-Fauré S, Andrieux A, Fourest-Lieuvin A, Fauré J, Marty I. Deletion of the microtubule-associated protein 6 (MAP6) results in skeletal muscle dysfunction. Skelet Muscle 2018; 8:30. [PMID: 30231928 PMCID: PMC6147105 DOI: 10.1186/s13395-018-0176-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/12/2018] [Indexed: 01/23/2023] Open
Abstract
Background The skeletal muscle fiber has a specific and precise intracellular organization which is at the basis of an efficient muscle contraction. Microtubules are long known to play a major role in the function and organization of many cells, but in skeletal muscle, the contribution of the microtubule cytoskeleton to the efficiency of contraction has only recently been studied. The microtubule network is dynamic and is regulated by many microtubule-associated proteins (MAPs). In the present study, the role of the MAP6 protein in skeletal muscle organization and function has been studied using the MAP6 knockout mouse line. Methods The presence of MAP6 transcripts and proteins was shown in mouse muscle homogenates and primary culture using RT-PCR and western blot. The in vivo evaluation of muscle force of MAP6 knockout (KO) mice was performed on anesthetized animals using electrostimulation coupled to mechanical measurement and multimodal magnetic resonance. The impact of MAP6 deletion on microtubule organization and intracellular structures was studied using immunofluorescent labeling and electron microscopy, and on calcium release for muscle contraction using Fluo-4 calcium imaging on cultured myotubes. Statistical analysis was performed using Student’s t test or the Mann-Whitney test. Results We demonstrate the presence of MAP6 transcripts and proteins in skeletal muscle. Deletion of MAP6 results in a large number of muscle modifications: muscle weakness associated with slight muscle atrophy, alterations of microtubule network and sarcoplasmic reticulum organization, and reduction in calcium release. Conclusion Altogether, our results demonstrate that MAP6 is involved in skeletal muscle function. Its deletion results in alterations in skeletal muscle contraction which contribute to the global deleterious phenotype of the MAP6 KO mice. As MAP6 KO mouse line is a model for schizophrenia, our work points to a possible muscle weakness associated to some forms of schizophrenia. Electronic supplementary material The online version of this article (10.1186/s13395-018-0176-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Muriel Sébastien
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | | | - Perrine Aubin
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Julie Brocard
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Mathilde Chivet
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Laura Pietrangelo
- CeSI-Met & DNICS, University G. d' Annunzio of Chieti, I-66100, Chieti, Italy
| | - Simona Boncompagni
- CeSI-Met & DNICS, University G. d' Annunzio of Chieti, I-66100, Chieti, Italy
| | - Christophe Bosc
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Jacques Brocard
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - John Rendu
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CHU Grenoble, Biochimie et Génétique Moléculaire, F-38000, Grenoble, France
| | - Sylvie Gory-Fauré
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Annie Andrieux
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CEA-Grenoble, BIG, F-38000, Grenoble, France
| | - Anne Fourest-Lieuvin
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CEA-Grenoble, BIG, F-38000, Grenoble, France
| | - Julien Fauré
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CHU Grenoble, Biochimie et Génétique Moléculaire, F-38000, Grenoble, France
| | - Isabelle Marty
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France. .,University Grenoble Alpes, F-38000, Grenoble, France. .,GIN- Inserm U1216 - Bat EJ Safra, Chemin Fortuné Ferrini, 38700, La Tronche, France.
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17
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Takahara T, Arai Y, Kono Y, Shibata H, Maki M. A microtubule-associated protein MAP1B binds to and regulates localization of a calcium-binding protein ALG-2. Biochem Biophys Res Commun 2018; 497:492-498. [PMID: 29432744 DOI: 10.1016/j.bbrc.2018.02.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
Abstract
MAP1B (microtubule-associated protein 1B) binds to microtubules and regulates microtubule dynamics. Previously, we showed calcium-dependent interaction between MAP1B and a calcium-binding protein ALG-2 (apoptosis-linked gene 2), which is involved in regulation of the protein secretion pathway. Although ALG-2 generally binds to proteins through two consensus binding motifs such as ABM-1 and ABM-2, the absence of these motifs in MAP1B suggests a unique binding mode between MAP1B and ALG-2. Here, we identified the region of mouse MAP1B responsible for binding to ALG-2, and found point mutations that abrogated binding of MAP1B to ALG-2. Furthermore, interaction between MAP1B and ALG-2 selectively prevented ALG-2 from binding to proteins with ABM-2 such as Sec31A, suggesting competition between MAP1B and ABM-2-containing proteins for binding to ALG-2. Consistently, in MAP1B knockout cells, co-localization of ALG-2 with Sec31A was increased. Moreover, overexpression of wild-type MAP1B, but not the MAP1B mutant defective in ALG-2 binding, altered localizations of ALG-2 and Sec31A into dispersed distributions, suggesting that MAP1B regulates localizations of ALG-2 and Sec31A in the cells. Finally, we found two cancer-associated mutations of human MAP1B located near ALG-2 binding sites. The introduction of the corresponding mutations in mouse MAP1B dramatically reduced the binding ability to ALG-2. Thus, these results suggest that MAP1B plays a role in regulation of ALG-2 and Sec31A localizations, and that dysregulation of calcium-dependent binding of ALG-2 to MAP1B might influence pathological conditions such as cancers.
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Affiliation(s)
- Terunao Takahara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Aichi, Japan.
| | - Yumika Arai
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Aichi, Japan
| | - Yuta Kono
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Aichi, Japan
| | - Hideki Shibata
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Aichi, Japan
| | - Masatoshi Maki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Aichi, Japan.
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18
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Mutreja Y, Gamblin TC. Optimization of in vitro conditions to study the arachidonic acid induction of 4R isoforms of the microtubule-associated protein tau. Methods Cell Biol 2017; 141:65-88. [PMID: 28882312 DOI: 10.1016/bs.mcb.2017.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The microtubule-associated protein tau exists in six different isoforms that accumulate as filamentous aggregates in a wide spectrum of neurodegenerative diseases classified as tauopathies. One potential source of heterogeneity between these diseases could arise from differential tau isoform aggregation. in vitro assays employing arachidonic acid as an inducer of aggregation have been pivotal in gaining an understanding of the longest four repeat tau isoform (2N4R). These approaches have been less successful for modeling the shorter 1N4R and 0N4R tau isoforms in vitro. Through a careful analysis of in vitro conditions for aggregation, we found that the differences in the acidity of tau isoform N-terminal projection domains determine whether tau filaments cluster into larger assemblies in solution. Beyond the potential biological implications of filament clustering, we provide optimized conditions for the arachidonic acid induction of shorter 4R tau isoforms aggregation in vitro that greatly reduce filament clustering and improved modeling results.
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19
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Bakota L, Ussif A, Jeserich G, Brandt R. Systemic and network functions of the microtubule-associated protein tau: Implications for tau-based therapies. Mol Cell Neurosci 2017; 84:132-141. [PMID: 28318914 DOI: 10.1016/j.mcn.2017.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/23/2017] [Accepted: 03/05/2017] [Indexed: 01/04/2023] Open
Abstract
Tau is a microtubule-associated neuronal protein, whose primary role was long thought to regulate axonal microtubule assembly. Tau is subject to many posttranslational modifications and can aggregate into neurofibrillary tangles, which are considered to be a hallmark of several neurodegenerative diseases collectively called "tauopathies". The most common tauopathy is Alzheimer's disease, where tau pathology correlates with sites of neurodegeneration. Tau belongs to the class of intrinsically disordered proteins, which are known to interact with many partners and are considered to be involved in various signaling, regulation and recognition processes. Thus more recent evidence indicates that tau functionally interacts with many proteins and different cellular structures, which may have an important physiological role and may be involved in neurodegenerative processes. Furthermore, tau can be released from neurons and exert functional effects on other cells. This review article weighs the evidence that tau has subtle but important systemic effects on neuronal network function by maintaining physiological neuronal transmission and synaptic plasticity, which are possibly independent from tau's microtubule modulating activities. Implications for tau-based therapeutic approaches are discussed.
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Affiliation(s)
- Lidia Bakota
- Department of Neurobiology, University of Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Abdala Ussif
- Department of Neurobiology, University of Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Gunnar Jeserich
- Department of Neurobiology, University of Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Roland Brandt
- Department of Neurobiology, University of Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany.
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20
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Hoffman A, Taleski G, Sontag E. The protein serine/threonine phosphatases PP2A, PP1 and calcineurin: A triple threat in the regulation of the neuronal cytoskeleton. Mol Cell Neurosci 2017; 84:119-131. [PMID: 28126489 DOI: 10.1016/j.mcn.2017.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/16/2017] [Accepted: 01/21/2017] [Indexed: 01/08/2023] Open
Abstract
The microtubule, F-actin and neurofilament networks play a critical role in neuronal cell morphogenesis, polarity and synaptic plasticity. Significantly, the assembly/disassembly and stability of these cytoskeletal networks is crucially modulated by protein phosphorylation and dephosphorylation events. Herein, we aim to more closely examine the role played by three major neuronal Ser/Thr protein phosphatases, PP2A, PP1 and calcineurin, in the homeostasis of the neuronal cytoskeleton. There is strong evidence that these enzymes interact with and dephosphorylate a variety of cytoskeletal proteins, resulting in major regulation of neuronal cytoskeletal dynamics. Conversely, we also discuss how multi-protein cytoskeletal scaffolds can also influence the regulation of these phosphatases, with important implications for neuronal signalling and homeostasis. Not surprisingly, deregulation of these cytoskeletal scaffolds and phosphatase dysfunction are associated with many neurological diseases.
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Affiliation(s)
- Alexander Hoffman
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, and Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Goce Taleski
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, and Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Estelle Sontag
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, and Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW 2308, Australia.
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21
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Abstract
PAR-1/MARK kinases are conserved serine/threonine kinases that are essential regulators of cell polarity. PAR-1/MARK kinases localize and function in opposition to the anterior PAR proteins to control the asymmetric distribution of factors in a wide variety polarized cells. In this review, we discuss the mechanisms that control the localization and activity of PAR-1/MARK kinases, including their antagonistic interactions with the anterior PAR proteins. We focus on the role PAR-1 plays in the asymmetric division of the Caenorhabditis elegans zygote, in the establishment of the anterior/posterior axis in the Drosophila oocyte and in the control of microtubule dynamics in mammalian neurons. In addition to conserved aspects of PAR-1 biology, we highlight the unique ways in which PAR-1 acts in these distinct cell types to orchestrate their polarization. Finally, we review the connections between disruptions in PAR-1/MARK function and Alzheimer's disease and cancer.
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Affiliation(s)
- Youjun Wu
- Dartmouth College, Hanover, NH, United States
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22
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Zuo YC, Li HL, Xiong NX, Shen JY, Huang YZ, Fu P, Zhao HY. Overexpression of Tau Rescues Nogo-66-Induced Neurite Outgrowth Inhibition In Vitro. Neurosci Bull 2016; 32:577-584. [PMID: 27761788 DOI: 10.1007/s12264-016-0068-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/23/2016] [Indexed: 12/14/2022] Open
Abstract
Nogo-66 plays a central role in the myelin-mediated inhibition of neurite outgrowth. Tau is a microtubule-associated protein involved in microtubule assembly and stabilization. It remains unverified whether tau interacts directly with growth factor receptors, or engages in cross-talk with regeneration inhibitors like Nogo-66. Here, we report that plasmid overexpression of tau significantly elevated the protein levels of total tau, phosphorylated tau, and microtubule-affinity regulating kinase (MARK). Nogo-66 transiently elevated the total tau protein level and persistently reduced the level of p-S262 tau (tau phosphorylated at serine 262), whereas it had little influence on the level of p-T205 tau (tau phosphorylated at threonine 205). Nogo-66 significantly decreased the protein level of MARK. Hymenialdisine, an inhibitor of MARK, significantly reduced the level of p-S262 tau. Overexpression of tau rescued the Nogo-66-induced inhibition of neurite outgrowth in neuroblastoma 2a (N2a) cells and primary cortical neurons. However, concomitant inhibition of MARK abolished the rescue of neurite outgrowth by tau in N2a cells. We conclude that dephosphorylation of tau at S262 is able to regulate Nogo-66 signaling, and that overexpression of tau can rescue the Nogo-66-induced inhibition of neurite outgrowth in vitro.
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Affiliation(s)
- Yu-Chao Zuo
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Hong-Lian Li
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Nan-Xiang Xiong
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Jian-Ying Shen
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yi-Zhi Huang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Peng Fu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hong-Yang Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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23
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Cox K, Combs B, Abdelmesih B, Morfini G, Brady ST, Kanaan NM. Analysis of isoform-specific tau aggregates suggests a common toxic mechanism involving similar pathological conformations and axonal transport inhibition. Neurobiol Aging 2016; 47:113-126. [PMID: 27574109 DOI: 10.1016/j.neurobiolaging.2016.07.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/01/2016] [Accepted: 07/21/2016] [Indexed: 12/14/2022]
Abstract
Misfolded tau proteins are characteristic of tauopathies, but the isoform composition of tau inclusions varies by tauopathy. Using aggregates of the longest tau isoform (containing 4 microtubule-binding repeats and 4-repeat tau), we recently described a direct mechanism of toxicity that involves exposure of the N-terminal phosphatase-activating domain (PAD) in tau, which triggers a signaling pathway that disrupts axonal transport. However, the impact of aggregation on PAD exposure for other tau isoforms was unexplored. Here, results from immunochemical assays indicate that aggregation-induced increases in PAD exposure and oligomerization are common features among all tau isoforms. The extent of PAD exposure and oligomerization was larger for tau aggregates composed of 4-repeat isoforms compared with those made of 3-repeat isoforms. Most important, aggregates of all isoforms exhibited enough PAD exposure to significantly impair axonal transport in the squid axoplasm. We also show that PAD exposure and oligomerization represent common pathological characteristics in multiple tauopathies. Collectively, these results suggest a mechanism of toxicity common to each tau isoform that likely contributes to degeneration in different tauopathies.
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Affiliation(s)
- Kristine Cox
- Department of Translational Science and Molecular Medicine, Michigan State University, College of Human Medicine, Grand Rapids, MI, USA; Marine Biological Laboratory, Woods Hole, MA, USA; California National Primate Research Center, University of California, Davis, CA, USA
| | - Benjamin Combs
- Department of Translational Science and Molecular Medicine, Michigan State University, College of Human Medicine, Grand Rapids, MI, USA; Marine Biological Laboratory, Woods Hole, MA, USA
| | | | - Gerardo Morfini
- Marine Biological Laboratory, Woods Hole, MA, USA; Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Scott T Brady
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA; Marine Biological Laboratory, Woods Hole, MA, USA
| | - Nicholas M Kanaan
- Department of Translational Science and Molecular Medicine, Michigan State University, College of Human Medicine, Grand Rapids, MI, USA; Neuroscience Program, Michigan State University, East Lansing, MI, USA; Hauenstein Neuroscience Center, Mercy Health Saint Mary's, Grand Rapids, MI, USA.
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24
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Reid TA, Schuster BM, Mann BJ, Balchand SK, Plooster M, McClellan M, Coombes CE, Wadsworth P, Gardner MK. Suppression of microtubule assembly kinetics by the mitotic protein TPX2. J Cell Sci 2016; 129:1319-28. [PMID: 26869224 DOI: 10.1242/jcs.178806] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 02/05/2016] [Indexed: 01/01/2023] Open
Abstract
TPX2 is a widely conserved microtubule-associated protein that is required for mitotic spindle formation and function. Previous studies have demonstrated that TPX2 is required for the nucleation of microtubules around chromosomes; however, the molecular mechanism by which TPX2 promotes microtubule nucleation remains a mystery. In this study, we found that TPX2 acts to suppress tubulin subunit off-rates during microtubule assembly and disassembly, thus allowing for the support of unprecedentedly slow rates of plus-end microtubule growth, and also leading to a dramatically reduced microtubule shortening rate. These changes in microtubule dynamics can be explained in computational simulations by a moderate increase in tubulin-tubulin bond strength upon TPX2 association with the microtubule lattice, which in turn acts to reduce the departure rate of tubulin subunits from the microtubule ends. Thus, the direct suppression of tubulin subunit off-rates by TPX2 during microtubule growth and shortening could provide a molecular mechanism to explain the nucleation of new microtubules in the presence of TPX2.
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Affiliation(s)
- Taylor A Reid
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Breanna M Schuster
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Barbara J Mann
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Melissa Plooster
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark McClellan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Courtney E Coombes
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Pat Wadsworth
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Melissa K Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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Bonneau C, Gurard-Levin ZA, Andre F, Pusztai L, Rouzier R. Predictive and Prognostic Value of the TauProtein in Breast Cancer. Anticancer Res 2015; 35:5179-5184. [PMID: 26408675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
BACKGROUND/AIM Predictive markers for response to chemotherapy are required in breast cancer. The Tau protein is a microtubule-associated protein variably expressed in breast cancer. The objective of our study was to describe drug resistance induced by the tau protein, and its predictive and prognostic value in breast cancer. MATERIALS AND METHODS Medline and PubMed databases were searched in April 2015 for terms "tau protein", "breast cancer", "chemotherapy sensitivity", "biomarker" and "taxane resistance". RESULTS In vitro, tau protein competes with taxane for controlling microtubule dynamic and loss of tau expression may render microtubules more vulnerable to the effects of taxanes. High tau protein expression was associated with better prognosis, even after adjustment for grade, hormone receptor and human epidermal growth factor receptor-2 expression, nodal status. The predictive value of the tau protein for sensitivity to taxane is discordant despite there being a trend for an association between low tau expression and increased response rate. CONCLUSION Tau protein expression is insufficient for identifying a subset of patients with carcinomas that may benefit more from chemotherapy.
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Affiliation(s)
- Claire Bonneau
- Department of Breast and Gynaecological Surgery, Curie Institute, Versailles-St-Quentin-en-Yvelines University, Versailles, France
| | - Zachary A Gurard-Levin
- UMR3664: "Dynamic of the cell nucleus" Unit, National Center for scientific Research (CNRS), Curie Institute, Paris, France
| | - Fabrice Andre
- UMR 981: "Predictive biomarkers and new molecular therapeutic strategies in cancer", Integrated Research Cancer Institute in Villejuif, Paris, France
| | - Lajos Pusztai
- Yale Cancer Center Genetics and Genomics Program, Yale School of Medicine, New Haven, CT, U.S.A
| | - Roman Rouzier
- Department of Breast and Gynaecological Surgery, Curie Institute, Versailles-St-Quentin-en-Yvelines University, Versailles, France EA 7285: "Clinics risks and security in women's health and perinatal health", Versailles-St-Quentin-en-Yvelines University, Versailles, France
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Abstract
In this article, we will summarize recent progress in understanding the mechanical origins of rigidity, strength, resiliency and stress transmission in the MT cytoskeleton using reconstituted networks formed from purified components. We focus on the role of network architecture, crosslinker compliance and dynamics, and molecular determinants of single filament elasticity, while highlighting open questions and future directions for this work.
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Affiliation(s)
- Benjamin J Lopez
- Department of Mechanical Engineering and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106-5070, USA
| | - Megan T Valentine
- Department of Mechanical Engineering and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106-5070, USA.
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Brehm H, Hristodorov D, Pardo A, Mladenov R, Niesen J, Fischer R, Tur MK, Barth S. Targeted killing of rhabdomyosarcoma cells by a MAP-based human cytolytic fusion protein. Cancer Lett 2015; 365:149-55. [PMID: 25888452 DOI: 10.1016/j.canlet.2015.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 04/02/2015] [Accepted: 04/04/2015] [Indexed: 12/26/2022]
Abstract
The treatment of rhabdomyosarcoma (RMS) is challenging, and the prognosis remains especially poor for high-grade RMS with metastasis. The conventional treatment of RMS is based on multi-agent chemotherapy combined with resection and radiotherapy, which are often marked by low success rate. Alternative therapeutic options include the combination of standard treatments with immunotherapy. We generated a microtubule-associated protein (MAP)-based fully human cytolytic fusion protein (hCFP) targeting the fetal acetylcholine receptor, which is expressed on RMS cells. We were able to express and purify functional scFv35-MAP from Escherichia coli cells. Moreover, we found that scFv35-MAP is rapidly internalized by target cells after binding its receptor, and exhibits specific cytotoxicity toward FL-OH1 and RD cells in vitro. We also confirmed that scFv35-MAP induces apoptosis in FL-OH1 and RD cells. The in vivo potential of scFv35-MAP will need to be considered in further studies.
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Yang S, Cacquevel M, Saksida LM, Bussey TJ, Schneider BL, Aebischer P, Melani R, Pizzorusso T, Fawcett JW, Spillantini MG. Perineuronal net digestion with chondroitinase restores memory in mice with tau pathology. Exp Neurol 2014; 265:48-58. [PMID: 25483398 PMCID: PMC4353684 DOI: 10.1016/j.expneurol.2014.11.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/24/2014] [Accepted: 11/26/2014] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease is the most prevalent tauopathy and cause of dementia. We investigate the hypothesis that reactivation of plasticity can restore function in the presence of neuronal damage resulting from tauopathy. We investigated two models with tau hyperphosphorylation, aggregation and neurodegeneration: a transgenic mouse model in which the mutant P301S tau is expressed in neurons (Tg P301S), and a model in which an adeno-associated virus expressing P301S tau (AAV-P301S) was injected in the perirhinal cortex, a region critical for object recognition (OR) memory. Both models show profound loss of OR memory despite only 15% neuronal loss in the Tg P301S and 26% in AAV-P301S-injected mice. Recordings from perirhinal cortex slices of 3month-old P301S transgenic mice showed a diminution in synaptic transmission following temporal stimulation. Chondroitinase ABC (ChABC) can reactivate plasticity and affect memory through actions on perineuronal nets. ChABC was injected into the perirhinal cortex and animals were tested for OR memory 1week later, demonstrating restoration of OR memory to normal levels. Synaptic transmission indicated by fEPSP amplitude was restored to control levels following ChABC treatment. ChABC did not affect the progression of neurodegenerative tauopathy. These findings suggest that increasing plasticity by manipulation of perineuronal nets offers a novel therapeutic approach to the treatment of memory loss in neurodegenerative disorders.
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Affiliation(s)
- Sujeong Yang
- John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Matthias Cacquevel
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Lisa M Saksida
- Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom; MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom
| | - Timothy J Bussey
- Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom; MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Patrick Aebischer
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | | | - Tommaso Pizzorusso
- Inst Neuroscience CNR, via Moruzzi 1, 56125 Pisa, Italy; NEUROFARBA Dept, University of Florence, Area S. Salvi Pad. 26, 50135 Florence, Italy
| | - James W Fawcett
- John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Maria Grazia Spillantini
- John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge CB2 0PY, United Kingdom.
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Tegha-Dunghu J, Bausch E, Neumann B, Wuensche A, Walter T, Ellenberg J, Gruss OJ. MAP1S controls microtubule stability throughout the cell cycle in human cells. J Cell Sci 2014; 127:5007-13. [PMID: 25300793 DOI: 10.1242/jcs.136457] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Summary Understanding the molecular basis for proper cell division requires a detailed functional analysis of microtubule (MT)-associated proteins. MT-associated protein 1S (MAP1S), the most ubiquitously expressed MAP1 family member, is required for accurate cell division. Here, using quantitative analysis of MT plus-end tracking, we show that MAP1S knockdown alters MT dynamics throughout the cell cycle. Surprisingly, MAP1S downregulation results in faster growing, yet short-lived, MTs in all cell cycle stages and in a global loss of MT acetylation. These aberrations correlate with severe defects in the final stages of cell division. In monopolar cytokinesis assays, we demonstrate that MAP1S guides MT-dependent initiation of cytokinesis. Our data underline the key role of MAP1S as a global regulator of MT stability and demonstrate a new primary function of MAP1S to regulate MT dynamics at the onset of cytokinesis.
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Affiliation(s)
- Justus Tegha-Dunghu
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Elena Bausch
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Beate Neumann
- European Molecular Biology Laboratory (EMBL), Advanced Light Microscopy Facility Programme, Meyerhostr.1, 69117 Heidelberg, Germany
| | - Annelie Wuensche
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Programme, Meyerhostr.1, 69117 Heidelberg, Germany
| | - Thomas Walter
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Programme, Meyerhostr.1, 69117 Heidelberg, Germany
| | - Jan Ellenberg
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Programme, Meyerhostr.1, 69117 Heidelberg, Germany
| | - Oliver J Gruss
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
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Abstract
In the crowded environment of eukaryotic cells, diffusion is an inefficient distribution mechanism for cellular components. Long-distance active transport is required and is performed by molecular motors including kinesins. Furthermore, in highly polarised, compartmentalised and plastic cells such as neurons, regulatory mechanisms are required to ensure appropriate spatio-temporal delivery of neuronal components. The kinesin machinery has diversified into a large number of kinesin motor proteins as well as adaptor proteins that are associated with subsets of cargo. However, many mechanisms contribute to the correct delivery of these cargos to their target domains. One mechanism is through motor recognition of sub-domain-specific microtubule (MT) tracks, sign-posted by different tubulin isoforms, tubulin post-translational modifications, tubulin GTPase activity and MT-associated proteins (MAPs). With neurons as a model system, a critical review of these regulatory mechanisms is presented here, with a particular focus on the emerging contribution of compartmentalised MAPs. Overall, we conclude that - especially for axonal cargo - alterations to the MT track can influence transport, although in vivo, it is likely that multiple track-based effects act synergistically to ensure accurate cargo distribution.
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Affiliation(s)
- Joseph Atherton
- Institute of Structural and Molecular Biology, Birkbeck College, London, WC1E 7HX, UK
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Tsvetkov PO, Barbier P, Breuzard G, Peyrot V, Devred F. Microtubule-associated proteins and tubulin interaction by isothermal titration calorimetry. Methods Cell Biol 2013; 115:283-302. [PMID: 23973079 DOI: 10.1016/B978-0-12-407757-7.00018-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microtubules play an important role in a number of vital cell processes such as cell division, intracellular transport, and cell architecture. The highly dynamic structure of microtubules is tightly regulated by a number of stabilizing and destabilizing microtubule-associated proteins (MAPs), such as tau and stathmin. Because of their importance, tubulin-MAPs interactions have been extensively studied using various methods that provide researchers with complementary but sometimes contradictory thermodynamic data. Isothermal titration calorimetry (ITC) is the only direct thermodynamic method that enables a full thermodynamic characterization (stoichiometry, enthalpy, entropy of binding, and association constant) of the interaction after a single titration experiment. This method has been recently applied to study tubulin-MAPs interactions in order to bring new insights into molecular mechanisms of tubulin regulation. In this chapter, we review the technical specificity of this method and then focus on the use of ITC in the investigation of tubulin-MAPs binding. We describe technical issues which could arise during planning and carrying out the ITC experiments, in particular with fragile proteins such as tubulin. Using examples of stathmin and tau, we demonstrate how ITC can be used to gain major insights into tubulin-MAP interaction.
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