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Zhang Y, Sung HH, Ziegler AB, Wu YC, Viais R, Sánchez-Huertas C, Kilo L, Agircan FG, Cheng YJ, Mouri K, Uemura T, Lüders J, Chien CT, Tavosanis G. Augmin complex activity finetunes dendrite morphology through non-centrosomal microtubule nucleation in vivo. J Cell Sci 2024; 137:jcs261512. [PMID: 38587100 PMCID: PMC11128282 DOI: 10.1242/jcs.261512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 04/03/2024] [Indexed: 04/09/2024] Open
Abstract
During development, neurons achieve a stereotyped neuron type-specific morphology, which relies on dynamic support by microtubules (MTs). An important player is the augmin complex (hereafter augmin), which binds to existing MT filaments and recruits the γ-tubulin ring complex (γ-TuRC), to form branched MTs. In cultured neurons, augmin is important for neurite formation. However, little is known about the role of augmin during neurite formation in vivo. Here, we have revisited the role of mammalian augmin in culture and then turned towards the class four Drosophila dendritic arborization (c4da) neurons. We show that MT density is maintained through augmin in cooperation with the γ-TuRC in vivo. Mutant c4da neurons show a reduction of newly emerging higher-order dendritic branches and in turn also a reduced number of their characteristic space-filling higher-order branchlets. Taken together, our data reveal a cooperative function for augmin with the γ-TuRC in forming enough MTs needed for the appropriate differentiation of morphologically complex dendrites in vivo.
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Affiliation(s)
- Yun Zhang
- German Center for Neurodegenerative Diseases (DZNE), Dynamics of Neuronal Circuits Group, Venusberg Campus 1 Building 99, 53127 Bonn, Germany
| | - Hsin-Ho Sung
- Institute of Molecular Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Anna B. Ziegler
- German Center for Neurodegenerative Diseases (DZNE), Dynamics of Neuronal Circuits Group, Venusberg Campus 1 Building 99, 53127 Bonn, Germany
| | - Ying-Chieh Wu
- Institute of Molecular Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Ricardo Viais
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Carlos Sánchez-Huertas
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Lukas Kilo
- German Center for Neurodegenerative Diseases (DZNE), Dynamics of Neuronal Circuits Group, Venusberg Campus 1 Building 99, 53127 Bonn, Germany
| | - Fikret Gürkan Agircan
- German Center for Neurodegenerative Diseases (DZNE), Dynamics of Neuronal Circuits Group, Venusberg Campus 1 Building 99, 53127 Bonn, Germany
| | - Ying-Ju Cheng
- Institute of Molecular Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Kousuke Mouri
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- Center for Living Systems Information Science, Kyoto University
| | - Jens Lüders
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Cheng-Ting Chien
- Institute of Molecular Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Gaia Tavosanis
- German Center for Neurodegenerative Diseases (DZNE), Dynamics of Neuronal Circuits Group, Venusberg Campus 1 Building 99, 53127 Bonn, Germany
- LIMES Institute, University of Bonn, 53115 Bonn, Germany
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2
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Xu Y, Wang B, Bush I, Saunders HAJ, Wildonger J, Han C. Light-induced trapping of endogenous proteins reveals spatiotemporal roles of microtubule and kinesin-1 in dendrite patterning of Drosophila sensory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.30.560303. [PMID: 37873262 PMCID: PMC10592855 DOI: 10.1101/2023.09.30.560303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Animal development involves numerous molecular events, whose spatiotemporal properties largely determine the biological outcomes. Conventional methods for studying gene function lack the necessary spatiotemporal resolution for precise dissection of developmental mechanisms. Optogenetic approaches are powerful alternatives, but most existing tools rely on exogenous designer proteins that produce narrow outputs and cannot be applied to diverse or endogenous proteins. To address this limitation, we developed OptoTrap, a light-inducible protein trapping system that allows manipulation of endogenous proteins tagged with GFP or split GFP. This system turns on fast and is reversible in minutes or hours. We generated OptoTrap variants optimized for neurons and epithelial cells and demonstrate effective trapping of endogenous proteins of diverse sizes, subcellular locations, and functions. Furthermore, OptoTrap allowed us to instantly disrupt microtubules and inhibit the kinesin-1 motor in specific dendritic branches of Drosophila sensory neurons. Using OptoTrap, we obtained direct evidence that microtubules support the growth of highly dynamic dendrites. Similarly, targeted manipulation of Kinesin heavy chain revealed differential spatiotemporal requirements of kinesin-1 in the patterning of low- and high-order dendritic branches, suggesting that different cargos are needed for the growth of these branches. OptoTrap allows for precise manipulation of endogenous proteins in a spatiotemporal manner and thus holds great promise for studying developmental mechanisms in a wide range of cell types and developmental stages.
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Affiliation(s)
- Yineng Xu
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Inle Bush
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Harriet AJ Saunders
- Department of Biochemistry, University of Wisconsin-Madison, 440 Henry Mall, Madison, WI 53706, USA
| | - Jill Wildonger
- Department of Biochemistry, University of Wisconsin-Madison, 440 Henry Mall, Madison, WI 53706, USA
- Pediatrics Department and Biological Sciences Division, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Chun Han
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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Zocchi R, Compagnucci C, Bertini E, Sferra A. Deciphering the Tubulin Language: Molecular Determinants and Readout Mechanisms of the Tubulin Code in Neurons. Int J Mol Sci 2023; 24:ijms24032781. [PMID: 36769099 PMCID: PMC9917122 DOI: 10.3390/ijms24032781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/17/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Microtubules (MTs) are dynamic components of the cell cytoskeleton involved in several cellular functions, such as structural support, migration and intracellular trafficking. Despite their high similarity, MTs have functional heterogeneity that is generated by the incorporation into the MT lattice of different tubulin gene products and by their post-translational modifications (PTMs). Such regulations, besides modulating the tubulin composition of MTs, create on their surface a "biochemical code" that is translated, through the action of protein effectors, into specific MT-based functions. This code, known as "tubulin code", plays an important role in neuronal cells, whose highly specialized morphologies and activities depend on the correct functioning of the MT cytoskeleton and on its interplay with a myriad of MT-interacting proteins. In recent years, a growing number of mutations in genes encoding for tubulins, MT-interacting proteins and enzymes that post-translationally modify MTs, which are the main players of the tubulin code, have been linked to neurodegenerative processes or abnormalities in neural migration, differentiation and connectivity. Nevertheless, the exact molecular mechanisms through which the cell writes and, downstream, MT-interacting proteins decipher the tubulin code are still largely uncharted. The purpose of this review is to describe the molecular determinants and the readout mechanisms of the tubulin code, and briefly elucidate how they coordinate MT behavior during critical neuronal events, such as neuron migration, maturation and axonal transport.
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Affiliation(s)
- Riccardo Zocchi
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
| | - Claudia Compagnucci
- Molecular Genetics and Functional Genomics, Bambino Gesù Children’s Research Hospital, IRCCS, 00146 Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
- Correspondence: (E.B.); or (A.S.); Tel.: +39-06-6859-2104 (E.B. & A.S.)
| | - Antonella Sferra
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
- Correspondence: (E.B.); or (A.S.); Tel.: +39-06-6859-2104 (E.B. & A.S.)
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4
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Nakamura A, Ikeda M, Kusayanagi S, Hayashi K. An alternative splice isoform of mouse CDK5RAP2 induced cytoplasmic microtubule nucleation. IBRO Neurosci Rep 2022; 13:264-273. [PMID: 36164503 PMCID: PMC9508486 DOI: 10.1016/j.ibneur.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/11/2022] [Indexed: 10/29/2022] Open
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5
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Hu C, Feng P, Chen M, Tang Y, Soba P. Spatiotemporal changes in microtubule dynamics during dendritic morphogenesis. Fly (Austin) 2022; 16:13-23. [PMID: 34609266 PMCID: PMC8496546 DOI: 10.1080/19336934.2021.1976033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/25/2021] [Accepted: 08/30/2021] [Indexed: 10/25/2022] Open
Abstract
Dendritic morphogenesis requires dynamic microtubules (MTs) to form a coordinated cytoskeletal network during development. Dynamic MTs are characterized by their number, polarity and speed of polymerization. Previous studies described a correlation between anterograde MT growth and terminal branch extension in Drosophila dendritic arborization (da) neurons, suggesting a model that anterograde MT polymerization provides a driving force for dendritic branching. We recently found that the Ste20-like kinase Tao specifically regulates dendritic branching by controlling the number of dynamic MTs in a kinase activity-dependent fashion, without affecting MT polarity or speed. This finding raises the interesting question of how MT dynamics affects dendritic morphogenesis, and if Tao kinase activity is developmentally regulated to coordinate MT dynamics and dendritic morphogenesis. We explored the possible correlation between MT dynamics and dendritic morphogenesis together with the activity changes of Tao kinase in C1da and C4da neurons during larval development. Our data show that spatiotemporal changes in the number of dynamic MTs, but not polarity or polymerization speed, correlate with dendritic branching and Tao kinase activity. Our findings suggest that Tao kinase limits dendritic branching by controlling the abundance of dynamic MTs and we propose a novel model on how regulation of MT dynamics might influence dendritic morphogenesis.
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Affiliation(s)
- Chun Hu
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, China, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Pan Feng
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, China, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Meilan Chen
- Department of Ophthalmology, The Second People’s Hospital of Guangdong Province, Guangzhou, China
| | - Yan Tang
- Molecular Brain Physiology and Behavior, Limes Institute, University of Bonn, Bonn, Germany
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Soba
- Molecular Brain Physiology and Behavior, Limes Institute, University of Bonn, Bonn, Germany
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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6
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Gabel CA, Li Z, DeMarco AG, Zhang Z, Yang J, Hall MC, Barford D, Chang L. Molecular architecture of the augmin complex. Nat Commun 2022; 13:5449. [PMID: 36114186 PMCID: PMC9481612 DOI: 10.1038/s41467-022-33227-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 09/05/2022] [Indexed: 12/21/2022] Open
Abstract
Accurate segregation of chromosomes during mitosis depends on the correct assembly of the mitotic spindle, a bipolar structure composed mainly of microtubules. The augmin complex, or homologous to augmin subunits (HAUS) complex, is an eight-subunit protein complex required for building robust mitotic spindles in metazoa. Augmin increases microtubule density within the spindle by recruiting the γ-tubulin ring complex (γ-TuRC) to pre-existing microtubules and nucleating branching microtubules. Here, we elucidate the molecular architecture of augmin by single particle cryo-electron microscopy (cryo-EM), computational methods, and crosslinking mass spectrometry (CLMS). Augmin's highly flexible structure contains a V-shaped head and a filamentous tail, with the head existing in either extended or contracted conformational states. Our work highlights how cryo-EM, complemented by computational advances and CLMS, can elucidate the structure of a challenging protein complex and provides insights into the function of augmin in mediating microtubule branching nucleation.
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Affiliation(s)
- Clinton A Gabel
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhuang Li
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA
| | - Andrew G DeMarco
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Ziguo Zhang
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Jing Yang
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Mark C Hall
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - David Barford
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Leifu Chang
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA.
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA.
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7
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Yap CC, Winckler B. Spatial regulation of endosomes in growing dendrites. Dev Biol 2022; 486:5-14. [PMID: 35306006 PMCID: PMC10646839 DOI: 10.1016/j.ydbio.2022.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/21/2022] [Accepted: 03/13/2022] [Indexed: 01/19/2023]
Abstract
Many membrane proteins are highly enriched in either dendrites or axons. This non-uniform distribution is a critical feature of neuronal polarity and underlies neuronal function. The molecular mechanisms responsible for polarized distribution of membrane proteins has been studied for some time and many answers have emerged. A less well studied feature of neurons is that organelles are also frequently non-uniformly distributed. For instance, EEA1-positive early endosomes are somatodendritic whereas synaptic vesicles are axonal. In addition, some organelles are present in both axons and dendrites, but not distributed uniformly along the processes. One well known example are lysosomes which are abundant in the soma and proximal dendrite, but sparse in the distal dendrite and the distal axon. The mechanisms that determine the spatial distribution of organelles along dendrites are only starting to be studied. In this review, we will discuss the cell biological mechanisms of how the distribution of diverse sets of endosomes along the proximal-distal axis of dendrites might be regulated. In particular, we will focus on the regulation of bulk homeostatic mechanisms as opposed to local regulation. We posit that immature dendrites regulate organelle motility differently from mature dendrites in order to spatially organize dendrite growth, branching and sculpting.
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8
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Li H, Gavis ER. The Drosophila fragile X mental retardation protein modulates the neuronal cytoskeleton to limit dendritic arborization. Development 2022; 149:275257. [DOI: 10.1242/dev.200379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/21/2022] [Indexed: 01/02/2023]
Abstract
ABSTRACT
Dendritic arbor development is a complex, highly regulated process. Post-transcriptional regulation mediated by RNA-binding proteins plays an important role in neuronal dendrite morphogenesis by delivering on-site, on-demand protein synthesis. Here, we show how the Drosophila fragile X mental retardation protein (FMRP), a conserved RNA-binding protein, limits dendrite branching to ensure proper neuronal function during larval sensory neuron development. FMRP knockdown causes increased dendritic terminal branch growth and a resulting overelaboration defect due, in part, to altered microtubule stability and dynamics. FMRP also controls dendrite outgrowth by regulating the Drosophila profilin homolog chickadee (chic). FMRP colocalizes with chic mRNA in dendritic granules and regulates its dendritic localization and protein expression. Whereas RNA-binding domains KH1 and KH2 are both crucial for FMRP-mediated dendritic regulation, KH2 specifically is required for FMRP granule formation and chic mRNA association, suggesting a link between dendritic FMRP granules and FMRP function in dendrite elaboration. Our studies implicate FMRP-mediated modulation of both the neuronal microtubule and actin cytoskeletons in multidendritic neuronal architecture, and provide molecular insight into FMRP granule formation and its relevance to FMRP function in dendritic patterning.
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Affiliation(s)
- Hui Li
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Elizabeth R. Gavis
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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9
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Joseph NF, Swarnkar S, Puthanveettil SV. Double Duty: Mitotic Kinesins and Their Post-Mitotic Functions in Neurons. Cells 2021; 10:cells10010136. [PMID: 33445569 PMCID: PMC7827351 DOI: 10.3390/cells10010136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 01/06/2021] [Accepted: 01/06/2021] [Indexed: 01/23/2023] Open
Abstract
Neurons, regarded as post-mitotic cells, are characterized by their extensive dendritic and axonal arborization. This unique architecture imposes challenges to how to supply materials required at distal neuronal components. Kinesins are molecular motor proteins that mediate the active delivery of cellular materials along the microtubule cytoskeleton for facilitating the local biochemical and structural changes at the synapse. Recent studies have made intriguing observations that some kinesins that function during neuronal mitosis also have a critical role in post-mitotic neurons. However, we know very little about the function and regulation of such kinesins. Here, we summarize the known cellular and biochemical functions of mitotic kinesins in post-mitotic neurons.
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Affiliation(s)
- Nadine F. Joseph
- The Skaggs Graduate School of Chemical and Biological Sciences, Scripps Research Institute, La Jolla, CA 92037, USA;
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA;
| | - Supriya Swarnkar
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA;
| | - Sathyanarayanan V Puthanveettil
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA;
- Correspondence: ; Tel.: +1-561-228-3504; Fax: +1-568-228-2249
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10
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Zhang H, Wang H, Shen X, Jia X, Yu S, Qiu X, Wang Y, Du J, Yan J, He J. The landscape of regulatory genes in brain-wide neuronal phenotypes of a vertebrate brain. eLife 2021; 10:68224. [PMID: 34895465 PMCID: PMC8769648 DOI: 10.7554/elife.68224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 12/05/2021] [Indexed: 11/18/2022] Open
Abstract
Multidimensional landscapes of regulatory genes in neuronal phenotypes at whole-brain levels in the vertebrate remain elusive. We generated single-cell transcriptomes of ~67,000 region- and neurotransmitter/neuromodulator-identifiable cells from larval zebrafish brains. Hierarchical clustering based on effector gene profiles ('terminal features') distinguished major brain cell types. Sister clusters at hierarchical termini displayed similar terminal features. It was further verified by a population-level statistical method. Intriguingly, glutamatergic/GABAergic sister clusters mostly expressed distinct transcription factor (TF) profiles ('convergent pattern'), whereas neuromodulator-type sister clusters predominantly expressed the same TF profiles ('matched pattern'). Interestingly, glutamatergic/GABAergic clusters with similar TF profiles could also display different terminal features ('divergent pattern'). It led us to identify a library of RNA-binding proteins that differentially marked divergent pair clusters, suggesting the post-transcriptional regulation of neuron diversification. Thus, our findings reveal multidimensional landscapes of transcriptional and post-transcriptional regulators in whole-brain neuronal phenotypes in the zebrafish brain.
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Affiliation(s)
- Hui Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,University of Chinese Academy of SciencesBeijingChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Haifang Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Xiaoyu Shen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Xinling Jia
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Shuguang Yu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,University of Chinese Academy of SciencesBeijingChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Xiaoying Qiu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Yufan Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,University of Chinese Academy of SciencesBeijingChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
| | - Jiulin Du
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina,School of Future Technology, University of Chinese Academy of SciencesBeijingChina
| | - Jun Yan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina,School of Future Technology, University of Chinese Academy of SciencesBeijingChina
| | - Jie He
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghaiChina,Shanghai Center for Brain Science and Brain-Inspired Intelligence TechnologyShanghaiChina
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11
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Zhu H, Ying S, Zhou B, Liang X, He Q, Song P, Hu X, Shi K, Xiong M, Jin H, Pan Y. Discovery of novel 2-aryl-3-sulfonamido-pyridines (HoAns) as microtubule polymerization inhibitors with potent antitumor activities. Eur J Med Chem 2020; 211:113117. [PMID: 33360794 DOI: 10.1016/j.ejmech.2020.113117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022]
Abstract
Microtubules play a vital role in cell mitosis. Drugs targeting taxol or vinca binding site of tubulin have been proved an effective way to against cancer. However, drug resistance and cancer recurrence are inevitable, there is an urgent need to search for new microtubule-targeting agents (MTAs). In our study, a series of novel 2-aryl-3-sulfonamido-pyridines (HoAns) had been designed, synthesized, and evaluated for their antiproliferative activities in vitro and in vivo. Among them, compound HoAn32 exhibited the most potent activity with IC50 values ranging from 0.170 to 1.193 μM in a panel of cancer cell lines. Mechanism studies indicated that compound HoAn32 bound to the colchicine site of β-tubulin, resulting in colony formation inhibition, G2/M phase cell cycle arrest, cell apoptosis as well as increased the generation of ROS in both RKO and SW620 cells. In addition, compound HoAn32 showed potent anti-vascular activity in vitro. Furthermore, compound HoAn32 also exhibited outstanding antitumor activity in SW620 xenograft tumor models without observable toxic effects, which was more potent than that of ABT-751. In conclusion, our findings suggest that compound HoAn32 may be a promising microtubule destabilizing agent and deserves for further development in cancer therapy.
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Affiliation(s)
- Heping Zhu
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
| | - Shilong Ying
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Bingluo Zhou
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Xiao Liang
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Quan He
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
| | - Ping Song
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Xinyang Hu
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Keqiang Shi
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China
| | - Mingteng Xiong
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
| | - Hongchuan Jin
- Laboratory of Cancer Biology, Key Lab of Biotherapy in Zhejiang, Sir Run Run Shaw Hospital, Medical School of Zhejiang University, Hangzhou, 310020, PR China.
| | - Yuanjiang Pan
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China.
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12
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Ferreira Castro A, Baltruschat L, Stürner T, Bahrami A, Jedlicka P, Tavosanis G, Cuntz H. Achieving functional neuronal dendrite structure through sequential stochastic growth and retraction. eLife 2020; 9:e60920. [PMID: 33241995 PMCID: PMC7837678 DOI: 10.7554/elife.60920] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/15/2020] [Indexed: 02/06/2023] Open
Abstract
Class I ventral posterior dendritic arborisation (c1vpda) proprioceptive sensory neurons respond to contractions in the Drosophila larval body wall during crawling. Their dendritic branches run along the direction of contraction, possibly a functional requirement to maximise membrane curvature during crawling contractions. Although the molecular machinery of dendritic patterning in c1vpda has been extensively studied, the process leading to the precise elaboration of their comb-like shapes remains elusive. Here, to link dendrite shape with its proprioceptive role, we performed long-term, non-invasive, in vivo time-lapse imaging of c1vpda embryonic and larval morphogenesis to reveal a sequence of differentiation stages. We combined computer models and dendritic branch dynamics tracking to propose that distinct sequential phases of stochastic growth and retraction achieve efficient dendritic trees both in terms of wire and function. Our study shows how dendrite growth balances structure-function requirements, shedding new light on general principles of self-organisation in functionally specialised dendrites.
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Affiliation(s)
- André Ferreira Castro
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with Max Planck SocietyFrankfurt am MainGermany
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
| | | | - Tomke Stürner
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | | | - Peter Jedlicka
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Faculty of Medicine, ICAR3R – Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University GiessenGiessenGermany
- Neuroscience Center, Institute of Clinical Neuroanatomy, Goethe UniversityFrankfurt am MainGermany
| | - Gaia Tavosanis
- Center for Neurodegenerative Diseases (DZNE)BonnGermany
- LIMES Institute, University of BonnBonnGermany
| | - Hermann Cuntz
- Frankfurt Institute for Advanced StudiesFrankfurt am MainGermany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with Max Planck SocietyFrankfurt am MainGermany
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13
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Wilkes OR, Moore AW. Distinct Microtubule Organizing Center Mechanisms Combine to Generate Neuron Polarity and Arbor Complexity. Front Cell Neurosci 2020; 14:594199. [PMID: 33328893 PMCID: PMC7711044 DOI: 10.3389/fncel.2020.594199] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/02/2020] [Indexed: 01/15/2023] Open
Abstract
Dendrite and axon arbor wiring patterns determine the connectivity and computational characteristics of a neuron. The identities of these dendrite and axon arbors are created by differential polarization of their microtubule arrays, and their complexity and pattern are generated by the extension and organization of these arrays. We describe how several molecularly distinct microtubule organizing center (MTOC) mechanisms function during neuron differentiation to generate and arrange dendrite and axon microtubules. The temporal and spatial organization of these MTOCs generates, patterns, and diversifies arbor wiring.
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Affiliation(s)
- Oliver R Wilkes
- Laboratory for Neurodiversity, RIKEN Center for Brain Science, Wako-shi, Japan.,Department of Cellular and Molecular Biology, Institute for Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Adrian W Moore
- Laboratory for Neurodiversity, RIKEN Center for Brain Science, Wako-shi, Japan
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14
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Yang SZ, Wildonger J. Golgi Outposts Locally Regulate Microtubule Orientation in Neurons but Are Not Required for the Overall Polarity of the Dendritic Cytoskeleton. Genetics 2020; 215:435-447. [PMID: 32265236 PMCID: PMC7268992 DOI: 10.1534/genetics.119.302979] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/29/2020] [Indexed: 11/24/2022] Open
Abstract
Microtubule-organizing centers often play a central role in organizing the cellular microtubule networks that underlie cell function. In neurons, microtubules in axons and dendrites have distinct polarities. Dendrite-specific Golgi "outposts," in particular multicompartment outposts, have emerged as regulators of acentrosomal microtubule growth, raising the question of whether outposts contribute to establishing or maintaining the overall polarity of the dendritic microtubule cytoskeleton. Using a combination of genetic approaches and live imaging in a Drosophila model, we found that dendritic microtubule polarity is unaffected by eliminating known regulators of Golgi-dependent microtubule organization including the cis-Golgi matrix protein GM130, the fly AKAP450 ortholog pericentrin-like protein, and centrosomin. This indicates that Golgi outposts are not essential for the formation or maintenance of a dendrite-specific cytoskeleton. However, the overexpression of GM130, which promotes the formation of ectopic multicompartment units, is sufficient to alter dendritic microtubule polarity. Axonal microtubule polarity is similarly disrupted by the presence of ectopic multicompartment Golgi outposts. Notably, multicompartment outposts alter microtubule polarity independently of microtubule nucleation mediated by the γ-tubulin ring complex. Thus, although Golgi outposts are not essential to dendritic microtubule polarity, altering their organization correlates with changes to microtubule polarity. Based on these data, we propose that the organization of Golgi outposts is carefully regulated to ensure proper dendritic microtubule polarity.
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Affiliation(s)
- Sihui Z Yang
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Wisconsin 53706
- Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
| | - Jill Wildonger
- Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
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15
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Yoong LF, Lim HK, Tran H, Lackner S, Zheng Z, Hong P, Moore AW. Atypical Myosin Tunes Dendrite Arbor Subdivision. Neuron 2020; 106:452-467.e8. [DOI: 10.1016/j.neuron.2020.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/30/2019] [Accepted: 01/31/2020] [Indexed: 12/13/2022]
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16
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Ahamad A, Wang J, Ge S, Kirschen GW. Early Dendritic Morphogenesis of Adult-Born Dentate Granule Cells Is Regulated by FHL2. Front Neurosci 2020; 14:202. [PMID: 32256309 PMCID: PMC7090230 DOI: 10.3389/fnins.2020.00202] [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: 10/28/2019] [Accepted: 02/24/2020] [Indexed: 11/13/2022] Open
Abstract
Dentate granule cells (DGCs), the progeny of neural stem cells (NSCs) in the sub-granular zone of the dentate gyrus (DG), must develop and functionally integrate with the mature cohort of neurons in order to maintain critical hippocampal functions throughout adulthood. Dysregulation in the continuum of DGC development can result in aberrant morphology and disrupted functional maturation, impairing neuroplasticity of the network. Yet, the molecular underpinnings of the signaling involved in adult-born DGC maturation including dendritic growth, which correlates with functional integration, remains incompletely understood. Given the high metabolic activity in the dentate gyrus (DG) required to achieve continuous neurogenesis, we investigated the potential regulatory role of a cellular metabolism-linked gene recently implicated in NSC cycling and neuroblast migration, called Four and a half LIM domain 2 (FHL2). The FHL2 protein modulates numerous pathways related to proliferation, migration, survival and cytoskeletal rearrangement in peripheral tissues, interacting with the machinery of the sphingosine-1-phosphate pathway, also known to be highly active especially in the hippocampus. Yet, the potential relevance of FHL2 to adult-born DGC development remains unknown. To elucidate the role of FHL2 in DGC development in the adult brain, we first confirmed the endogenous expression of FHL2 in NSCs and new granule cells within the DG, then engineered viral vectors for genetic manipulation experiments, investigating morphological changes in early stages of DGC development. Overexpression of FHL2 during early DGC development resulted in marked sprouting and branching of dendrites, while silencing of FHL2 increased dendritic length. Together, these findings suggest a novel role of FHL2 in adult-born DGC morphological maturation, which may open up a new line of investigation regarding the relevance of this gene in physiology and pathologies of the hippocampus such as mesial temporal lobe epilepsy (MTLE).
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Affiliation(s)
- Afrinash Ahamad
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, NY, United States.,School of Health Technology and Management, Stony Brook University, Stony Brook, NY, United States
| | - Jia Wang
- Biomedical Pioneering Innovation Center, Peking University, Beijing, China
| | - Shaoyu Ge
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
| | - Gregory W Kirschen
- Medical Scientist Training Program (MSTP), Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
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17
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Martineau FS, Sahu S, Plantier V, Buhler E, Schaller F, Fournier L, Chazal G, Kawasaki H, Represa A, Watrin F, Manent JB. Correct Laminar Positioning in the Neocortex Influences Proper Dendritic and Synaptic Development. Cereb Cortex 2019; 28:2976-2990. [PMID: 29788228 PMCID: PMC6041803 DOI: 10.1093/cercor/bhy113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Indexed: 01/28/2023] Open
Abstract
The neocortex is a 6-layered laminated structure with a precise anatomical and functional organization ensuring proper function. Laminar positioning of cortical neurons, as determined by termination of neuronal migration, is a key determinant of their ability to assemble into functional circuits. However, the exact contribution of laminar placement to dendrite morphogenesis and synapse formation remains unclear. Here we manipulated the laminar position of cortical neurons by knocking down doublecortin (Dcx), a crucial effector of migration, and show that misplaced neurons fail to properly form dendrites, spines, and functional glutamatergic and GABAergic synapses. We further show that knocking down Dcx in properly positioned neurons induces similar but milder defects, suggesting that the laminar misplacement is the primary cause of altered neuronal development. Thus, the specific laminar environment of their fated layers is crucial for the maturation of cortical neurons, and influences their functional integration into developing cortical circuits.
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Affiliation(s)
| | - Surajit Sahu
- INMED, Aix-Marseille University, INSERM U901, Marseille, France
| | | | | | | | | | | | - Hiroshi Kawasaki
- Department of Medical Neuroscience, Graduate School of Medical Sciences, Kanazawa University, Ishikawa, Japan
| | - Alfonso Represa
- INMED, Aix-Marseille University, INSERM U901, Marseille, France
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18
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Araújo SJ. Centrosomes in Branching Morphogenesis. Results Probl Cell Differ 2019; 67:323-336. [PMID: 31435801 DOI: 10.1007/978-3-030-23173-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The centrosome, a major microtubule organizer, has important functions in regulating the cytoskeleton as well as the position of cellular structures and orientation of cells within tissues. The centrosome serves as the main cytoskeleton-organizing centre in the cell and is the classical site of microtubule nucleation and anchoring. For these reasons, centrosomes play a very important role in morphogenesis, not just in the early stages of cell divisions but also in the later stages of organogenesis. Many organs such as lung, kidney and blood vessels develop from epithelial tubes that branch into complex networks. Cells in the nervous system also form highly branched structures in order to build complex neuronal networks. During branching morphogenesis, cells have to rearrange within tissues though multicellular branching or through subcellular branching, also known as single-cell branching. For highly branched structures to be formed during embryonic development, the cytoskeleton needs to be extensively remodelled. The centrosome has been shown to play an important role during these events.
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Affiliation(s)
- Sofia J Araújo
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain.
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19
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Harish RK, Tendulkar S, Deivasigamani S, Ratnaparkhi A, Ratnaparkhi GS. Monensin Sensitive 1 Regulates Dendritic Arborization in Drosophila by Modulating Endocytic Flux. Front Cell Dev Biol 2019; 7:145. [PMID: 31428611 PMCID: PMC6687774 DOI: 10.3389/fcell.2019.00145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/16/2019] [Indexed: 12/03/2022] Open
Abstract
Monensin Sensitive 1 (Mon1) is a component of the Mon1:Ccz1 complex that mediates Rab5 to Rab7 conversion in eukaryotic cells by serving as a guanine nucleotide exchange factor for Rab7 during vesicular trafficking. We find that Mon1 activity modulates the complexity of Class IV dendritic arborization (da) neurons during larval development. Loss of Mon1 function leads to an increase in arborization and complexity, while increased expression, leads to reduced arborization. The ability of Mon1 to influence dendritic development is possibly a function of its interactions with Rab family GTPases that are central players in vesicular trafficking. Earlier, these GTPases, specifically Rab1, Rab5, Rab10, and Rab11 have been shown to regulate dendritic arborization. We have conducted genetic epistasis experiments, by modulating the activity of Rab5, Rab7, and Rab11 in da neurons, in Mon1 mutants, and demonstrate that the ability of Mon1 to regulate arborization is possibly due to its effect on the recycling pathway. Dendritic branching is critical for proper connectivity and physiological function of the neuron. An understanding of regulatory elements, such as Mon1, as demonstrated in our study, is essential to understand neuronal function.
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Affiliation(s)
| | - Shweta Tendulkar
- Indian Institutes of Science Education and Research, Pune, India
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20
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Golgi Fragmentation in Neurodegenerative Diseases: Is There a Common Cause? Cells 2019; 8:cells8070748. [PMID: 31331075 PMCID: PMC6679019 DOI: 10.3390/cells8070748] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 02/06/2023] Open
Abstract
In most mammalian cells, the Golgi complex forms a continuous ribbon. In neurodegenerative diseases, the Golgi ribbon of a specific group of neurons is typically broken into isolated elements, a very early event which happens before clinical and other pathological symptoms become evident. It is not known whether this phenomenon is caused by mechanisms associated with cell death or if, conversely, it triggers apoptosis. When the phenomenon was studied in diseases such as Parkinson’s and Alzheimer’s or amyotrophic lateral sclerosis, it was attributed to a variety of causes, including the presence of cytoplasmatic protein aggregates, malfunctioning of intracellular traffic and/or alterations in the cytoskeleton. In the present review, we summarize the current findings related to these and other neurodegenerative diseases and try to search for clues on putative common causes.
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21
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Sundararajan L, Smith CJ, Watson JD, Millis BA, Tyska MJ, Miller DM. Actin assembly and non-muscle myosin activity drive dendrite retraction in an UNC-6/Netrin dependent self-avoidance response. PLoS Genet 2019; 15:e1008228. [PMID: 31220078 PMCID: PMC6605669 DOI: 10.1371/journal.pgen.1008228] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/02/2019] [Accepted: 06/04/2019] [Indexed: 01/08/2023] Open
Abstract
Dendrite growth is constrained by a self-avoidance response that induces retraction but the downstream pathways that balance these opposing mechanisms are unknown. We have proposed that the diffusible cue UNC-6(Netrin) is captured by UNC-40(DCC) for a short-range interaction with UNC-5 to trigger self-avoidance in the C. elegans PVD neuron. Here we report that the actin-polymerizing proteins UNC-34(Ena/VASP), WSP-1(WASP), UNC-73(Trio), MIG-10(Lamellipodin) and the Arp2/3 complex effect dendrite retraction in the self-avoidance response mediated by UNC-6(Netrin). The paradoxical idea that actin polymerization results in shorter rather than longer dendrites is explained by our finding that NMY-1 (non-muscle myosin II) is necessary for retraction and could therefore mediate this effect in a contractile mechanism. Our results also show that dendrite length is determined by the antagonistic effects on the actin cytoskeleton of separate sets of effectors for retraction mediated by UNC-6(Netrin) versus outgrowth promoted by the DMA-1 receptor. Thus, our findings suggest that the dendrite length depends on an intrinsic mechanism that balances distinct modes of actin assembly for growth versus retraction. Neurons may extend highly branched dendrites to detect input over a broad receptive field. The formation of actin filaments may drive dendrite elongation. The architecture of the dendritic arbor also depends on mechanisms that limit expansion. For example, sister dendrites from a single neuron usually do not overlap due to self-avoidance. Although cell surface proteins are known to mediate self-avoidance, the downstream pathways that drive dendrite retraction in this phenomenon are largely unknown. Studies of the highly branched PVD sensory neuron in C. elegans have suggested a model of self-avoidance in which the UNC-40/DCC receptor captures the diffusible cue UNC-6/Netrin at the tips of PVD dendrites where it interacts with the UNC-5 receptor on an opposing sister dendrite to induce retraction. Here we report genetic evidence that UNC-5-dependent retraction requires downstream actin polymerization. This finding evokes a paradox: How might actin polymerization drive both dendrite growth and retraction? We propose two answers: (1) Distinct sets of effectors are involved in actin assembly for growth vs retraction; (2) Non-muscle myosin interacts with a nascent actin assemblage to trigger retraction. Our results show that dendrite length depends on the balanced effects of specific molecular components that induce growth vs retraction.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Cody J. Smith
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Joseph D. Watson
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Bryan A. Millis
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Cell Imaging Shared Resource, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David M. Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- * E-mail:
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22
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Sundararajan L, Stern J, Miller DM. Mechanisms that regulate morphogenesis of a highly branched neuron in C. elegans. Dev Biol 2019; 451:53-67. [PMID: 31004567 DOI: 10.1016/j.ydbio.2019.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/09/2019] [Accepted: 04/05/2019] [Indexed: 02/08/2023]
Abstract
The shape of an individual neuron is linked to its function with axons sending signals to other cells and dendrites receiving them. Although much is known of the mechanisms for axonal outgrowth, the striking complexity of dendritic architecture has hindered efforts to uncover pathways that direct dendritic branching. Here we review the results of an experimental strategy that exploits the power of genetic analysis and live cell imaging of the PVD sensory neuron in C. elegans to reveal key molecular drivers of dendrite morphogenesis.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jamie Stern
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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23
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Abstract
Neurons are polarized cells with long branched axons and dendrites. Microtubule generation and organization machineries are crucial to grow and pattern these complex cellular extensions. Microtubule organizing centers (MTOCs) concentrate the molecular machinery for templating microtubules, stabilizing the nascent polymer, and organizing the resultant microtubules into higher-order structures. MTOC formation and function are well described at the centrosome, in the spindle, and at interphase Golgi; we review these studies and then describe recent results about how the machineries acting at these classic MTOCs are repurposed in the postmitotic neuron for axon and dendrite differentiation. We further discuss a constant tug-of-war interplay between different MTOC activities in the cell and how this process can be used as a substrate for transcription factor-mediated diversification of neuron types.
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Affiliation(s)
- Jason Y Tann
- Laboratory for Neurodiversity, RIKEN Centre for Brain Science, Saitama, Japan
| | - Adrian W Moore
- Laboratory for Neurodiversity, RIKEN Centre for Brain Science, Saitama, Japan.
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24
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Abstract
Proper neuronal wiring is central to all bodily functions, sensory perception, cognition, memory, and learning. Establishment of a functional neuronal circuit is a highly regulated and dynamic process involving axonal and dendritic branching and navigation toward appropriate targets and connection partners. This intricate circuitry includes axo-dendritic synapse formation, synaptic connections formed with effector cells, and extensive dendritic arborization that function to receive and transmit mechanical and chemical sensory inputs. Such complexity is primarily achieved by extensive axonal and dendritic branch formation and pruning. Fundamental to neuronal branching are cytoskeletal dynamics and plasma membrane expansion, both of which are regulated via numerous extracellular and intracellular signaling mechanisms and molecules. This review focuses on recent advances in understanding the biology of neuronal branching.
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Stephanie Gupton
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA.,Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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25
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Rao AN, Patil A, Black MM, Craig EM, Myers KA, Yeung HT, Baas PW. Cytoplasmic Dynein Transports Axonal Microtubules in a Polarity-Sorting Manner. Cell Rep 2018; 19:2210-2219. [PMID: 28614709 DOI: 10.1016/j.celrep.2017.05.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/20/2017] [Accepted: 05/18/2017] [Indexed: 01/20/2023] Open
Abstract
Axonal microtubules are predominantly organized into a plus-end-out pattern. Here, we tested both experimentally and with computational modeling whether a motor-based polarity-sorting mechanism can explain this microtubule pattern. The posited mechanism centers on cytoplasmic dynein transporting plus-end-out and minus-end-out microtubules into and out of the axon, respectively. When cytoplasmic dynein was acutely inhibited, the bi-directional transport of microtubules in the axon was disrupted in both directions, after which minus-end-out microtubules accumulated in the axon over time. Computational modeling revealed that dynein-mediated transport of microtubules can establish and preserve a predominantly plus-end-out microtubule pattern as per the details of the experimental findings, but only if a kinesin motor and a static cross-linker protein are also at play. Consistent with the predictions of the model, partial depletion of TRIM46, a protein that cross-links axonal microtubules in a manner that influences their polarity orientation, leads to an increase in microtubule transport.
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Affiliation(s)
- Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Ankita Patil
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA
| | - Mark M Black
- Department of Anatomy and Cell Biology, Temple University, Philadelphia, PA 19140, USA
| | - Erin M Craig
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Kenneth A Myers
- Department Biological Sciences, University of the Sciences, Philadelphia, PA 19104, USA
| | - Howard T Yeung
- Department of Physics, Central Washington University, Ellensburg, WA 98926, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA 19129, USA.
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26
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Rao AN, Baas PW. Polarity Sorting of Microtubules in the Axon. Trends Neurosci 2018; 41:77-88. [PMID: 29198454 PMCID: PMC5801152 DOI: 10.1016/j.tins.2017.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/30/2017] [Accepted: 11/08/2017] [Indexed: 01/03/2023]
Abstract
A longstanding question in cellular neuroscience is how microtubules in the axon become organized with their plus ends out, a pattern starkly different from the mixed orientation of microtubules in vertebrate dendrites. Recent attention has focused on a mechanism called polarity sorting, in which microtubules of opposite orientation are spatially separated by molecular motor proteins. Here we discuss this mechanism, and conclude that microtubules are polarity sorted in the axon by cytoplasmic dynein but that additional factors are also needed. In particular, computational modeling and experimental evidence suggest that static crosslinking proteins are required to appropriately restrict microtubule movements so that polarity sorting by cytoplasmic dynein can occur in a manner unimpeded by other motor proteins.
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Affiliation(s)
- Anand N Rao
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Peter W Baas
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 Queen Lane, Philadelphia, PA 19129, USA.
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27
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28
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Establishing Neuronal Polarity with Environmental and Intrinsic Mechanisms. Neuron 2017; 96:638-650. [DOI: 10.1016/j.neuron.2017.10.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/14/2017] [Accepted: 10/15/2017] [Indexed: 12/31/2022]
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29
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Luo B, Smith JW, Wu Z, Kim J, Ou Z, Chen Q. Polymerization-Like Co-Assembly of Silver Nanoplates and Patchy Spheres. ACS NANO 2017; 11:7626-7633. [PMID: 28715193 DOI: 10.1021/acsnano.7b02059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Highly anisometric nanoparticles have distinctive mechanical, electrical, and thermal properties and are therefore appealing candidates for use as self-assembly building blocks. Here, we demonstrate that ultra-anisometric nanoplates, which have a nanoscale thickness but a micrometer-scale edge length, offer many material design capabilities. In particular, we show that these nanoplates "copolymerize" in a predictable way with patchy spheres (Janus and triblock particles) into one- and two-dimensional structures with tunable architectural properties. We find that, on the pathway to these structures, nanoplates assemble into chains following the kinetics of molecular step-growth polymerization. In the same mechanistic framework, patchy spheres control the size distribution and morphology of assembled structures, by behaving as monofunctional chain stoppers or multifunctional branch points during nanoplate polymerization. In addition, both the lattice constant and the stiffness of the nanoplate assemblies can be manipulated after assembly. We see highly anisometric nanoplates as one representative of a broader class of dual length-scale nanoparticles, with the potential to enrich the library of structures and properties available to the nanoparticle self-assembly toolbox.
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Affiliation(s)
- Binbin Luo
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - John W Smith
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Zixuan Wu
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Juyeong Kim
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Zihao Ou
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Qian Chen
- Department of Materials Science and Engineering, ‡Frederick Seitz Materials Research Laboratory, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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Microtubule Organization Determines Axonal Transport Dynamics. Neuron 2017; 92:449-460. [PMID: 27764672 DOI: 10.1016/j.neuron.2016.09.036] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 08/02/2016] [Accepted: 09/15/2016] [Indexed: 12/31/2022]
Abstract
Axonal microtubule (MT) arrays are the major cytoskeleton substrate for cargo transport. How MT organization, i.e., polymer length, number, and minus-end spacing, is regulated and how it impinges on axonal transport are unclear. We describe a method for analyzing neuronal MT organization using light microscopy. This method circumvents the need for electron microscopy reconstructions and is compatible with live imaging of cargo transport and MT dynamics. Examination of a C. elegans motor neuron revealed how age, MT-associated proteins, and signaling pathways control MT length, minus-end spacing, and coverage. In turn, MT organization determines axonal transport progression: cargoes pause at polymer termini, suggesting that switching MT tracks is rate limiting for efficient transport. Cargo run length is set by MT length, and higher MT coverage correlates with shorter pauses. These results uncover the principles and mechanisms of neuronal MT organization and its regulation of axonal cargo transport.
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The role of the drebrin/EB3/Cdk5 pathway in dendritic spine plasticity, implications for Alzheimer's disease. Brain Res Bull 2016; 126:293-299. [PMID: 27365229 DOI: 10.1016/j.brainresbull.2016.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/23/2016] [Accepted: 06/25/2016] [Indexed: 11/21/2022]
Abstract
The drebrin/EB3/Cdk5 intracellular signalling pathway couples actin filaments to dynamic microtubules in cellular settings where cells are changing shape. The pathway has been most intensively studied in neuronal development, particularly neuritogenesis and neuronal migration, and in synaptic plasticity at dendritic spines in mature neurons. Drebrin is an actin filament side-binding and bundling protein that stabilises actin filaments. The end-binding (EB) proteins are microtubule plus-end tracking proteins (+TIPs) that localise to the growing plus-ends of dynamic microtubules and regulate their behavior and the binding of other +TIP proteins. EB3 binds specifically to drebrin when drebrin is bound to actin filaments, for example at the base of a growth cone filopodium, and EB3 is located at the plus-end of a growing microtubule inserting into the filopodium. This interaction therefore forms the basis for coupling dynamic microtubules to actin filaments in growth cones of developing neurons. Appropriate responses to growth cone guidance cues depend on actin filament/microtubule co-ordination in the growth cone, although the role of the drebrin/EB3/Cdk5 pathway in this context has not been directly tested. A similar cytoskeleton coupling pathway operates in dendritic spines in mature neurons where the activity-dependent insertion of dynamic microtubules into dendritic spines is facilitated by drebrin binding to EB3. Microtubule insertion into dendritic spines drives spine maturation during long-term potentiation and therefore has a role in synaptic plasticity and memory formation. In Alzheimer's disease and related chronic neurodegenerative diseases, there is an early and dramatic loss of drebrin from dendritic spines that precedes synapse loss and neurodegeneration and might contribute to a failure of synaptic plasticity and hence to cognitive decline.
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