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Hewitt VL, Miller-Fleming L, Twyning MJ, Andreazza S, Mattedi F, Prudent J, Polleux F, Vagnoni A, Whitworth AJ. Decreasing pdzd8-mediated mito-ER contacts improves organismal fitness and mitigates Aβ 42 toxicity. Life Sci Alliance 2022; 5:5/11/e202201531. [PMID: 35831024 PMCID: PMC9279675 DOI: 10.26508/lsa.202201531] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 02/02/2023] Open
Abstract
Mitochondria-ER contact sites (MERCs) orchestrate many important cellular functions including regulating mitochondrial quality control through mitophagy and mediating mitochondrial calcium uptake. Here, we identify and functionally characterize the Drosophila ortholog of the recently identified mammalian MERC protein, Pdzd8. We find that reducing pdzd8-mediated MERCs in neurons slows age-associated decline in locomotor activity and increases lifespan in Drosophila. The protective effects of pdzd8 knockdown in neurons correlate with an increase in mitophagy, suggesting that increased mitochondrial turnover may support healthy aging of neurons. In contrast, increasing MERCs by expressing a constitutive, synthetic ER-mitochondria tether disrupts mitochondrial transport and synapse formation, accelerates age-related decline in locomotion, and reduces lifespan. Although depletion of pdzd8 prolongs the survival of flies fed with mitochondrial toxins, it is also sufficient to rescue locomotor defects of a fly model of Alzheimer's disease expressing Amyloid β42 (Aβ42). Together, our results provide the first in vivo evidence that MERCs mediated by the tethering protein pdzd8 play a critical role in the regulation of mitochondrial quality control and neuronal homeostasis.
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Affiliation(s)
- Victoria L Hewitt
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Leonor Miller-Fleming
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Madeleine J Twyning
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Simonetta Andreazza
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Francesca Mattedi
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, IoPPN, King's College London, London, UK
| | - Julien Prudent
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
- Mortimer B Zuckerman Mind Brain Behavior Institute, New York, NY, USA
- Kavli Institute for Brain Sciences, Columbia University Medical Center, New York, NY, USA
| | - Alessio Vagnoni
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, IoPPN, King's College London, London, UK
| | - Alexander J Whitworth
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
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2
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Li H, Gavis ER. Drosophila FMRP controls miR-276-mediated regulation of nejire mRNA for space-filling dendrite development. G3 GENES|GENOMES|GENETICS 2022; 12:6697885. [PMID: 36102801 PMCID: PMC9635640 DOI: 10.1093/g3journal/jkac239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022]
Abstract
MicroRNAs are enriched in neurons and play important roles in dendritic spine development and synaptic plasticity. MicroRNA activity is controlled by a wide range of RNA-binding proteins. FMRP, a highly conserved RNA-binding protein, has been linked to microRNA-mediated gene regulation in axonal development and dendritic spine formation. FMRP also participates in dendritic arbor morphogenesis, but whether and how microRNAs contribute to its function in this process remains to be elucidated. Here, using Drosophila larval sensory neurons, we show that a FMRP-associated microRNA, miR-276, functions in FMRP-mediated space-filling dendrite morphogenesis. Using EGFP microRNA sensors, we demonstrate that FMRP likely acts by regulating miR-276a RNA targeting rather than by modulating microRNA levels. Supporting this conclusion, miR-276a coimmunoprecipitated with FMRP and this association was dependent on the FMRP KH domains. By testing putative targets of the FMRP–miR-276a regulatory axis, we identified nejire as a FMRP-associated mRNA and, using EGFP reporters, showed that the nejire 3′ untranslated region is a target of miR-276a in vivo. Genetic analysis places nejire downstream of the FMRP–miR-276a pathway in regulating dendrite patterning. Together, our findings support a model in which FMRP facilitates miR-276a-mediated control of nejire for proper dendrite space-filling morphology and shed light on microRNA-dependent dendrite developmental pathology of fragile X syndrome.
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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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3
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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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4
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Murakawa T, Nakamura T, Kawaguchi K, Murayama F, Zhao N, Stasevich TJ, Kimura H, Fujita N. A Drosophila toolkit for HA-tagged proteins unveils a block in autophagy flux in the last instar larval fat body. Development 2022; 149:274775. [DOI: 10.1242/dev.200243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/27/2022] [Indexed: 01/18/2023]
Abstract
ABSTRACT
For in vivo functional analysis of a protein of interest (POI), multiple transgenic strains with a POI that harbors different tags are needed but generation of these strains is still labor-intensive work. To overcome this, we have developed a versatile Drosophila toolkit with a genetically encoded single-chain variable fragment for the HA epitope tag: ‘HA Frankenbody’. This system allows various analyses of HA-tagged POI in live tissues by simply crossing an HA Frankenbody fly with an HA-tagged POI fly. Strikingly, the GFP-mCherry tandem fluorescent-tagged HA Frankenbody revealed a block in autophagic flux and an accumulation of enlarged autolysosomes in the last instar larval and prepupal fat body. Mechanistically, lysosomal activity was downregulated at this stage, and endocytosis, but not autophagy, was indispensable for the swelling of lysosomes. Furthermore, forced activation of lysosomes by fat body-targeted overexpression of Mitf, the single MiTF/TFE family gene in Drosophila, suppressed the lysosomal swelling and resulted in pupal lethality. Collectively, we propose that downregulated lysosomal function in the fat body plays a role in the metamorphosis of Drosophila.
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Affiliation(s)
- Tadayoshi Murakawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Tsuyoshi Nakamura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Kohei Kawaguchi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Futoshi Murayama
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Ning Zhao
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Timothy J. Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
- World Research Hub Initiative, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- World Research Hub Initiative, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Naonobu Fujita
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-11 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Precursory Research for Embryonic Science & Technology (PRESTO), Japan Science & Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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5
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Alizzi RA, Xu D, Tenenbaum CM, Wang W, Gavis ER. The ELAV/Hu protein Found in neurons regulates cytoskeletal and ECM adhesion inputs for space-filling dendrite growth. PLoS Genet 2020; 16:e1009235. [PMID: 33370772 PMCID: PMC7793258 DOI: 10.1371/journal.pgen.1009235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/08/2021] [Accepted: 10/29/2020] [Indexed: 12/17/2022] Open
Abstract
Dendritic arbor morphology influences how neurons receive and integrate extracellular signals. We show that the ELAV/Hu family RNA-binding protein Found in neurons (Fne) is required for space-filling dendrite growth to generate highly branched arbors of Drosophila larval class IV dendritic arborization neurons. Dendrites of fne mutant neurons are shorter and more dynamic than in wild-type, leading to decreased arbor coverage. These defects result from both a decrease in stable microtubules and loss of dendrite-substrate interactions within the arbor. Identification of transcripts encoding cytoskeletal regulators and cell-cell and cell-ECM interacting proteins as Fne targets using TRIBE further supports these results. Analysis of one target, encoding the cell adhesion protein Basigin, indicates that the cytoskeletal defects contributing to branch instability in fne mutant neurons are due in part to decreased Basigin expression. The ability of Fne to coordinately regulate the cytoskeleton and dendrite-substrate interactions in neurons may shed light on the behavior of cancer cells ectopically expressing ELAV/Hu proteins. Different types of neurons have different sizes and shapes that are tailored to their particular functions. In the fruit fly larva, a set of sensory neurons called class IV da neurons have highly branched trees of dendrites that cover the epidermis to sense potentially harmful stimuli. Neurons whose dendrites completely fill the territory they sample are also found in zebrafish, worms, mice and humans. We show that an RNA-binding protein called Fne plays an important role in coordinating different contributions to dendrite branching in class IV da neurons by impacting the organization of the cytoskeleton within the neuron and the ability of the dendrite to contact the substratum outside of it. The identification of mRNAs that code for cytoskeleton regulators and adhesive proteins as targets of Fne using a genome-wide approach further supports these results. While the ability of Fne to exert control over such proteins is crucial to generating the space-filling growth of neurons, it can be deleterious if not properly employed, such as when the homologs of Fne are expressed in cancer cells.
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Affiliation(s)
- Rebecca A. Alizzi
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Derek Xu
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Conrad M. Tenenbaum
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Wei Wang
- Lewis-Sigler Institute, Princeton University, Princeton, New Jersey, United States of America
| | - Elizabeth R. Gavis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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6
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Tang Q, Rui M, Bu S, Wang Y, Chew LY, Yu F. A microtubule polymerase is required for microtubule orientation and dendrite pruning in Drosophila. EMBO J 2020; 39:e103549. [PMID: 32267553 DOI: 10.15252/embj.2019103549] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 01/12/2023] Open
Abstract
Drosophila class IV ddaC neurons selectively prune all larval dendrites to refine the nervous system during metamorphosis. During dendrite pruning, severing of proximal dendrites is preceded by local microtubule (MT) disassembly. Here, we identify an unexpected role of Mini spindles (Msps), a conserved MT polymerase, in governing dendrite pruning. Msps associates with another MT-associated protein TACC, and both stabilize each other in ddaC neurons. Moreover, Msps and TACC are required to orient minus-end-out MTs in dendrites. We further show that the functions of msps in dendritic MT orientation and dendrite pruning are antagonized by the kinesin-13 MT depolymerase Klp10A. Excessive MT depolymerization, which is induced by pharmacological treatment and katanin overexpression, also perturbs dendritic MT orientation and dendrite pruning, phenocopying msps mutants. Thus, we demonstrate that the MT polymerase Msps is required to form dendritic minus-end-out MTs and thereby promotes dendrite pruning in Drosophila sensory neurons.
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Affiliation(s)
- Quan Tang
- Temasek Life Sciences Laboratory, Singapore City, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore City, Singapore
| | - Menglong Rui
- Temasek Life Sciences Laboratory, Singapore City, Singapore
| | - Shufeng Bu
- Temasek Life Sciences Laboratory, Singapore City, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore City, Singapore
| | - Yan Wang
- Temasek Life Sciences Laboratory, Singapore City, Singapore
| | - Liang Yuh Chew
- Temasek Life Sciences Laboratory, Singapore City, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore City, Singapore
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, Singapore City, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore City, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, Singapore City, Singapore.,Neuroscience and Behavioral Disorder Program, Duke-NUS Graduate Medical School Singapore, Singapore City, Singapore
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7
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Lebreton G, Géminard C, Lapraz F, Pyrpassopoulos S, Cerezo D, Spéder P, Ostap EM, Noselli S. Molecular to organismal chirality is induced by the conserved myosin 1D. Science 2019; 362:949-952. [PMID: 30467170 DOI: 10.1126/science.aat8642] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 10/04/2018] [Indexed: 11/02/2022]
Abstract
The emergence of asymmetry from an initially symmetrical state is a universal transition in nature. Living organisms show asymmetries at the molecular, cellular, tissular, and organismal level. However, whether and how multilevel asymmetries are related remains unclear. In this study, we show that Drosophila myosin 1D (Myo1D) and myosin 1C (Myo1C) are sufficient to generate de novo directional twisting of cells, single organs, or the whole body in opposite directions. Directionality lies in the myosins' motor domain and is swappable between Myo1D and Myo1C. In addition, Myo1D drives gliding of actin filaments in circular, counterclockwise paths in vitro. Altogether, our results reveal the molecular motor Myo1D as a chiral determinant that is sufficient to break symmetry at all biological scales through chiral interaction with the actin cytoskeleton.
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Affiliation(s)
- G Lebreton
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - C Géminard
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - F Lapraz
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - S Pyrpassopoulos
- Pennsylvania Muscle Institute and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - D Cerezo
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - P Spéder
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - E M Ostap
- Pennsylvania Muscle Institute and the Center for Engineering Mechanobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - S Noselli
- Université Côte D'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France.
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8
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Tenenbaum CM, Misra M, Alizzi RA, Gavis ER. Enclosure of Dendrites by Epidermal Cells Restricts Branching and Permits Coordinated Development of Spatially Overlapping Sensory Neurons. Cell Rep 2018; 20:3043-3056. [PMID: 28954223 DOI: 10.1016/j.celrep.2017.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 08/24/2017] [Accepted: 08/31/2017] [Indexed: 12/25/2022] Open
Abstract
Spatial arrangement of different neuron types within a territory is essential to neuronal development and function. How development of different neuron types is coordinated for spatial coexistence is poorly understood. In Drosophila, dendrites of four classes of dendritic arborization (C1-C4da) neurons innervate overlapping receptive fields within the larval epidermis. These dendrites are intermittently enclosed by epidermal cells, with different classes exhibiting varying degrees of enclosure. The role of enclosure in neuronal development and its underlying mechanism remain unknown. We show that the membrane-associated protein Coracle acts in C4da neurons and epidermal cells to locally restrict dendrite branching and outgrowth by promoting enclosure. Loss of C4da neuron enclosure results in excessive branching and growth of C4da neuron dendrites and retraction of C1da neuron dendrites due to local inhibitory interactions between neurons. We propose that enclosure of dendrites by epidermal cells is a developmental mechanism for coordinated innervation of shared receptive fields.
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Affiliation(s)
- Conrad M Tenenbaum
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mala Misra
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rebecca A Alizzi
- 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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β-III-spectrin spinocerebellar ataxia type 5 mutation reveals a dominant cytoskeletal mechanism that underlies dendritic arborization. Proc Natl Acad Sci U S A 2017; 114:E9376-E9385. [PMID: 29078305 DOI: 10.1073/pnas.1707108114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A spinocerebellar ataxia type 5 (SCA5) L253P mutation in the actin-binding domain (ABD) of β-III-spectrin causes high-affinity actin binding and decreased thermal stability in vitro. Here we show in mammalian cells, at physiological temperature, that the mutant ABD retains high-affinity actin binding. Significantly, we provide evidence that the mutation alters the mobility and recruitment of β-III-spectrin in mammalian cells, pointing to a potential disease mechanism. To explore this mechanism, we developed a Drosophila SCA5 model in which an equivalent mutant Drosophila β-spectrin is expressed in neurons that extend complex dendritic arbors, such as Purkinje cells, targeted in SCA5 pathogenesis. The mutation causes a proximal shift in arborization coincident with decreased β-spectrin localization in distal dendrites. We show that SCA5 β-spectrin dominantly mislocalizes α-spectrin and ankyrin-2, components of the endogenous spectrin cytoskeleton. Our data suggest that high-affinity actin binding by SCA5 β-spectrin interferes with spectrin-actin cytoskeleton dynamics, leading to a loss of a cytoskeletal mechanism in distal dendrites required for dendrite stabilization and arbor outgrowth.
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