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Karpova A, Aly AAA, Marosi EL, Mikulovic S. Fiber-based in vivo imaging: unveiling avenues for exploring mechanisms of synaptic plasticity and neuronal adaptations underlying behavior. NEUROPHOTONICS 2024; 11:S11507. [PMID: 38390518 PMCID: PMC10883581 DOI: 10.1117/1.nph.11.s1.s11507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
In recent decades, various subfields within neuroscience, spanning molecular, cellular, and systemic dimensions, have significantly advanced our understanding of the elaborate molecular and cellular mechanisms that underpin learning, memory, and adaptive behaviors. There have been notable advancements in imaging techniques, particularly in reaching superficial brain structures. This progress has led to their widespread adoption in numerous laboratories. However, essential physiological and cognitive processes, including sensory integration, emotional modulation of motivated behavior, motor regulation, learning, and memory consolidation, are intricately encoded within deeper brain structures. Hence, visualization techniques such as calcium imaging using miniscopes have gained popularity for studying brain activity in unrestrained animals. Despite its utility, miniscope technology is associated with substantial brain tissue damage caused by gradient refractive index lens implantation. Furthermore, its imaging capabilities are primarily confined to the neuronal somata level, thus constraining a comprehensive exploration of subcellular processes underlying adaptive behaviors. Consequently, the trajectory of neuroscience's future hinges on the development of minimally invasive optical fiber-based endo-microscopes optimized for cellular, subcellular, and molecular imaging within the intricate depths of the brain. In pursuit of this goal, select research groups have invested significant efforts in advancing this technology. In this review, we present a perspective on the potential impact of this innovation on various aspects of neuroscience, enabling the functional exploration of in vivo cellular and subcellular processes that underlie synaptic plasticity and the neuronal adaptations that govern behavior.
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Affiliation(s)
- Anna Karpova
- Leibniz Institute for Neurobiology, RG Neuroplasticity, Magdeburg, Germany
- Otto von Guericke University, Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Ahmed A A Aly
- Leibniz Institute for Neurobiology, RG Neuroplasticity, Magdeburg, Germany
| | - Endre Levente Marosi
- Leibniz Institute for Neurobiology, RG Cognition and Emotion, Magdeburg, Germany
| | - Sanja Mikulovic
- Otto von Guericke University, Center for Behavioral Brain Sciences, Magdeburg, Germany
- Leibniz Institute for Neurobiology, RG Cognition and Emotion, Magdeburg, Germany
- German Centre for Mental Health (DZPG), Magdeburg, Germany
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2
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Kroll J, Renkawitz J. Principles of organelle positioning in motile and non-motile cells. EMBO Rep 2024; 25:2172-2187. [PMID: 38627564 PMCID: PMC11094012 DOI: 10.1038/s44319-024-00135-4] [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: 11/13/2023] [Revised: 03/15/2024] [Accepted: 04/04/2024] [Indexed: 05/16/2024] Open
Abstract
Cells are equipped with asymmetrically localised and functionally specialised components, including cytoskeletal structures and organelles. Positioning these components to specific intracellular locations in an asymmetric manner is critical for their functionality and affects processes like immune responses, tissue maintenance, muscle functionality, and neurobiology. Here, we provide an overview of strategies to actively move, position, and anchor organelles to specific locations. By conceptualizing the cytoskeletal forces and the organelle-to-cytoskeleton connectivity, we present a framework of active positioning of both membrane-enclosed and membrane-less organelles. Using this framework, we discuss how different principles of force generation and organelle anchorage are utilised by different cells, such as mesenchymal and amoeboid cells, and how the microenvironment influences the plasticity of organelle positioning. Given that motile cells face the challenge of coordinating the positioning of their content with cellular motion, we particularly focus on principles of organelle positioning during migration. In this context, we discuss novel findings on organelle positioning by anchorage-independent mechanisms and their advantages and disadvantages in motile as well as stationary cells.
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Affiliation(s)
- Janina Kroll
- Biomedical Center, Walter Brendel Center of Experimental Medicine, Institute of Cardiovascular Physiology and Pathophysiology, Klinikum der Universität, Ludwig Maximilians Universität München, Munich, Germany
| | - Jörg Renkawitz
- Biomedical Center, Walter Brendel Center of Experimental Medicine, Institute of Cardiovascular Physiology and Pathophysiology, Klinikum der Universität, Ludwig Maximilians Universität München, Munich, Germany.
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3
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Findinier J, Joubert LM, Schmid MF, Malkovskiy A, Chiu W, Burlacot A, Grossman AR. Dramatic Changes in Mitochondrial Subcellular Location and Morphology Accompany Activation of the CO 2 Concentrating Mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586705. [PMID: 38585955 PMCID: PMC10996633 DOI: 10.1101/2024.03.25.586705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Dynamic changes in intracellular ultrastructure can be critical for the ability of organisms to acclimate to environmental conditions. Microalgae, which are responsible for ~50% of global photosynthesis, compartmentalize their Rubisco into a specialized structure known as the pyrenoid when the cells experience limiting CO2 conditions; this compartmentalization appears to be a component of the CO2 Concentrating Mechanism (CCM), which facilitates photosynthetic CO2 fixation as environmental levels of inorganic carbon (Ci) decline. Changes in the spatial distribution of mitochondria in green algae have also been observed under CO2 limiting conditions, although a role for this reorganization in CCM function remains unclear. We used the green microalgae Chlamydomonas reinhardtii to monitor changes in the position and ultrastructure of mitochondrial membranes as cells transition between high CO2 (HC) and Low/Very Low CO2 (LC/VLC). Upon transferring cells to VLC, the mitochondria move from a central to a peripheral location, become wedged between the plasma membrane and chloroplast envelope, and mitochondrial membranes orient in parallel tubular arrays that extend from the cell's apex to its base. We show that these ultrastructural changes require protein and RNA synthesis, occur within 90 min of shifting cells to VLC conditions, correlate with CCM induction and are regulated by the CCM master regulator CIA5. The apico-basal orientation of the mitochondrial membrane, but not the movement of the mitochondrion to the cell periphery, is dependent on microtubules and the MIRO1 protein, which is involved in membrane-microtubule interactions. Furthermore, blocking mitochondrial electron transport in VLC acclimated cells reduces the cell's affinity for inorganic carbon. Overall, our results suggest that CIA5-dependent mitochondrial repositioning/reorientation functions in integrating cellular architecture and energetics with CCM activities and invite further exploration of how intracellular architecture can impact fitness under dynamic environmental conditions.
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Affiliation(s)
- Justin Findinier
- The Carnegie Institution for Science, Biosphere Sciences & Engineering, Stanford, CA 94305, USA
| | - Lydia-Marie Joubert
- SLAC National Accelerator Laboratory, Division of CryoEM and Bioimaging, Menlo Park, CA 94025, USA
| | - Michael F. Schmid
- SLAC National Accelerator Laboratory, Division of CryoEM and Bioimaging, Menlo Park, CA 94025, USA
| | - Andrey Malkovskiy
- The Carnegie Institution for Science, Biosphere Sciences & Engineering, Stanford, CA 94305, USA
| | - Wah Chiu
- SLAC National Accelerator Laboratory, Division of CryoEM and Bioimaging, Menlo Park, CA 94025, USA
- Stanford University, Department of Bioengineering, Stanford, CA 94305, USA
| | - Adrien Burlacot
- The Carnegie Institution for Science, Biosphere Sciences & Engineering, Stanford, CA 94305, USA
- Stanford University, Biology Department, Stanford, CA 94305, USA
| | - Arthur R. Grossman
- The Carnegie Institution for Science, Biosphere Sciences & Engineering, Stanford, CA 94305, USA
- Stanford University, Biology Department, Stanford, CA 94305, USA
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4
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Bimbi G, Tongiorgi E. Chemical LTP induces confinement of BDNF mRNA under dendritic spines and BDNF protein accumulation inside the spines. Front Mol Neurosci 2024; 17:1348445. [PMID: 38450041 PMCID: PMC10914971 DOI: 10.3389/fnmol.2024.1348445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 02/05/2024] [Indexed: 03/08/2024] Open
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) plays a key role in neuronal development and synaptic plasticity. The discovery that BDNF mRNA can be transported in neuronal dendrites in an activity-dependent manner has suggested that its local translation may support synapse maturation and plasticity. However, a clear demonstration that BDNF mRNA is locally transported and translated at activated synapses in response to long-term potentiation (LTP) is still lacking. Here, we study the dynamics of BDNF mRNA dendritic trafficking following the induction of chemical LTP (cLTP). Dendritic transport of BDNF transcripts was analyzed using the MS2 system for mRNA visualization, and chimeric BDNF-GFP constructs were used to monitor protein synthesis in living neurons. We found that within 15 min from cLTP induction, most BDNF mRNA granules become stationary and transiently accumulate in the dendritic shaft at the base of the dendritic spines, while at 30 min they accumulate inside the spine, similar to the control CamkIIα mRNA which also increased inside the spines at 60 min post-cLTP. At 60 min but not at 15 min from cLTP induction, we observed an increase in BDNF protein levels within the spines. Taken together, these findings suggest that BDNF mRNA trafficking is arrested in the early phase of cLTP, providing a local source of mRNA for BDNF translation at the base of the spine followed by translocation of both the BDNF mRNA and protein within the spine head in the late phase of LTP.
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Affiliation(s)
| | - Enrico Tongiorgi
- Department of Life Sciences, University of Trieste, Trieste, Italy
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5
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Zhang W, Zhang Z, Xiang Y, Gu DD, Chen J, Chen Y, Zhai S, Liu Y, Jiang T, Liu C, He B, Yan M, Wang Z, Xu J, Cao YL, Deng B, Zeng D, Lei J, Zhuo J, Lei X, Long Z, Jin B, Chen T, Li D, Shen Y, Hu J, Gao S, Liu Q. Aurora kinase A-mediated phosphorylation triggers structural alteration of Rab1A to enhance ER complexity during mitosis. Nat Struct Mol Biol 2024; 31:219-231. [PMID: 38177680 DOI: 10.1038/s41594-023-01165-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/26/2023] [Indexed: 01/06/2024]
Abstract
Morphological rearrangement of the endoplasmic reticulum (ER) is critical for metazoan mitosis. Yet, how the ER is remodeled by the mitotic signaling remains unclear. Here, we report that mitotic Aurora kinase A (AURKA) employs a small GTPase, Rab1A, to direct ER remodeling. During mitosis, AURKA phosphorylates Rab1A at Thr75. Structural analysis demonstrates that Thr75 phosphorylation renders Rab1A in a constantly active state by preventing interaction with GDP-dissociation inhibitor (GDI). Activated Rab1A is retained on the ER and induces the oligomerization of ER-shaping protein RTNs and REEPs, eventually triggering an increase of ER complexity. In various models, from Caenorhabditis elegans and Drosophila to mammals, inhibition of Rab1AThr75 phosphorylation by genetic modifications disrupts ER remodeling. Thus, our study reveals an evolutionarily conserved mechanism explaining how mitotic kinase controls ER remodeling and uncovers a critical function of Rab GTPases in metaphase.
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Affiliation(s)
- Wei Zhang
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
- Department of Clinical Immunology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zijian Zhang
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Yun Xiang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dong-Dong Gu
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Jinna Chen
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Yifan Chen
- University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Shixian Zhai
- MOE Key Laboratory of Laser Life Science and College of Biophotonics, South China Normal University, Guangzhou, China
| | - Yong Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Jiang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chong Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bin He
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Min Yan
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Zifeng Wang
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Jie Xu
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Yu-Lu Cao
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Bing Deng
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Deshun Zeng
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Jie Lei
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Junxiao Zhuo
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Xinxing Lei
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Zijie Long
- Department of Hematology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Institute of Hematology, Sun Yat-sen University, Guangzhou, China
| | - Bilian Jin
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Tongsheng Chen
- MOE Key Laboratory of Laser Life Science and College of Biophotonics, South China Normal University, Guangzhou, China
| | - Dong Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yidong Shen
- University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - Song Gao
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China.
| | - Quentin Liu
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China.
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China.
- Institute of Hematology, Sun Yat-sen University, Guangzhou, China.
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6
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Zhang Y, Wang T, Cai Y, Cui T, Kuah M, Vicini S, Wang T. Role of α2δ-3 in regulating calcium channel localization at presynaptic active zones during homeostatic plasticity. Front Mol Neurosci 2023; 16:1253669. [PMID: 38025261 PMCID: PMC10662314 DOI: 10.3389/fnmol.2023.1253669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
The homeostatic modulation of synaptic transmission is an evolutionarily conserved mechanism that is critical for stabilizing the nervous system. At the Drosophila neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) compensates for impairments in postsynaptic glutamate receptors due to pharmacological blockade or genetic deletion. During PHP, there is an increase in presynaptic neurotransmitter release, counteracting postsynaptic changes and restoring excitation to baseline levels. Previous studies have shown that α2δ-3, an auxiliary subunit of voltage-gated calcium channels (VGCCs), is essential for both the rapid induction and sustained expression of PHP at the Drosophila NMJ. However, the molecular mechanisms by which α2δ-3 regulates neurotransmitter release during PHP remain to be elucidated. In this study, we utilized electrophysiological, confocal imaging, and super-resolution imaging approaches to explore how α2δ-3 regulates synaptic transmission during PHP. Our findings suggest that α2δ-3 governs PHP by controlling the localization of the calcium channel pore-forming α1 subunit at presynaptic release sites, or active zones. Moreover, we examined the role of two structural domains within α2δ-3 in regulating neurotransmitter release and calcium channel localization. Our results highlight that these domains in α2δ-3 serve distinct functions in controlling synaptic transmission and presynaptic calcium channel abundance, at baseline in the absence of perturbations and during PHP. In summary, our research offers compelling evidence that α2δ-3 is an indispensable signaling component for controlling calcium channel trafficking and stabilization in homeostatic plasticity.
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Affiliation(s)
- Yanfeng Zhang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, Jilin, China
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Ting Wang
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Yimei Cai
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Tao Cui
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Michelle Kuah
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, United States
| | - Tingting Wang
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, United States
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7
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Meng X, Yao D, Imaizumi K, Chen X, Kelley KW, Reis N, Thete MV, Arjun McKinney A, Kulkarni S, Panagiotakos G, Bassik MC, Pașca SP. Assembloid CRISPR screens reveal impact of disease genes in human neurodevelopment. Nature 2023; 622:359-366. [PMID: 37758944 PMCID: PMC10567561 DOI: 10.1038/s41586-023-06564-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/22/2023] [Indexed: 09/29/2023]
Abstract
The assembly of cortical circuits involves the generation and migration of interneurons from the ventral to the dorsal forebrain1-3, which has been challenging to study at inaccessible stages of late gestation and early postnatal human development4. Autism spectrum disorder and other neurodevelopmental disorders (NDDs) have been associated with abnormal cortical interneuron development5, but which of these NDD genes affect interneuron generation and migration, and how they mediate these effects remains unknown. We previously developed a platform to study interneuron development and migration in subpallial organoids and forebrain assembloids6. Here we integrate assembloids with CRISPR screening to investigate the involvement of 425 NDD genes in human interneuron development. The first screen aimed at interneuron generation revealed 13 candidate genes, including CSDE1 and SMAD4. We subsequently conducted an interneuron migration screen in more than 1,000 forebrain assembloids that identified 33 candidate genes, including cytoskeleton-related genes and the endoplasmic reticulum-related gene LNPK. We discovered that, during interneuron migration, the endoplasmic reticulum is displaced along the leading neuronal branch before nuclear translocation. LNPK deletion interfered with this endoplasmic reticulum displacement and resulted in abnormal migration. These results highlight the power of this CRISPR-assembloid platform to systematically map NDD genes onto human development and reveal disease mechanisms.
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Affiliation(s)
- Xiangling Meng
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - David Yao
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Kent Imaizumi
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Xiaoyu Chen
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Kevin W Kelley
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Noah Reis
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Mayuri Vijay Thete
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Arpana Arjun McKinney
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA
- Departments of Psychiatry and Neuroscience, Black Family Stem Cell Institute, Seaver Autism Center for Research and Treatment, Alper Center for Neural Development and Regeneration, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Shravanti Kulkarni
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA
| | - Georgia Panagiotakos
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
- Departments of Psychiatry and Neuroscience, Black Family Stem Cell Institute, Seaver Autism Center for Research and Treatment, Alper Center for Neural Development and Regeneration, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Sergiu P Pașca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
- Stanford Brain Organogenesis Program, Wu Tsai Neurosciences Institute and Bio-X, Stanford, CA, USA.
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Toader C, Eva L, Covache-Busuioc RA, Costin HP, Glavan LA, Corlatescu AD, Ciurea AV. Unraveling the Multifaceted Role of the Golgi Apparatus: Insights into Neuronal Plasticity, Development, Neurogenesis, Alzheimer's Disease, and SARS-CoV-2 Interactions. Brain Sci 2023; 13:1363. [PMID: 37891732 PMCID: PMC10605100 DOI: 10.3390/brainsci13101363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
This article critically evaluates the multifunctional role of the Golgi apparatus within neurological paradigms. We succinctly highlight its influence on neuronal plasticity, development, and the vital trafficking and sorting mechanisms for proteins and lipids. The discourse further navigates to its regulatory prominence in neurogenesis and its implications in Alzheimer's Disease pathogenesis. The emerging nexus between the Golgi apparatus and SARS-CoV-2 underscores its potential in viral replication processes. This consolidation accentuates the Golgi apparatus's centrality in neurobiology and its intersections with both neurodegenerative and viral pathologies. In essence, understanding the Golgi's multifaceted functions harbors profound implications for future therapeutic innovations in neurological and viral afflictions.
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Affiliation(s)
- Corneliu Toader
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
- Department of Vascular Neurosurgery, National Institute of Neurology and Neurovascular Diseases, 077160 Bucharest, Romania
| | - Lucian Eva
- Faculty of Medicine, “Dunarea de Jos” University of Galati, 800201 Galați, Romania
- Emergency Clinical Hospital “Prof. dr. N. Oblu”, 700309 Iasi, Romania
| | - Razvan-Adrian Covache-Busuioc
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
| | - Horia Petre Costin
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
| | - Luca-Andrei Glavan
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
| | - Antonio Daniel Corlatescu
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
| | - Alexandru Vlad Ciurea
- Department of Neurosurgery, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (C.T.); (H.P.C.); (L.-A.G.); (A.D.C.); (A.V.C.)
- Neurosurgery Department, Sanador Clinical Hospital, 010991 Bucharest, Romania
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9
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Parkkinen I, Their A, Asghar MY, Sree S, Jokitalo E, Airavaara M. Pharmacological Regulation of Endoplasmic Reticulum Structure and Calcium Dynamics: Importance for Neurodegenerative Diseases. Pharmacol Rev 2023; 75:959-978. [PMID: 37127349 DOI: 10.1124/pharmrev.122.000701] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest organelle of the cell, composed of a continuous network of sheets and tubules, and is involved in protein, calcium (Ca2+), and lipid homeostasis. In neurons, the ER extends throughout the cell, both somal and axodendritic compartments, and is highly important for neuronal functions. A third of the proteome of a cell, secreted and membrane-bound proteins, are processed within the ER lumen and most of these proteins are vital for neuronal activity. The brain itself is high in lipid content, and many structural lipids are produced, in part, by the ER. Cholesterol and steroid synthesis are strictly regulated in the ER of the blood-brain barrier protected brain cells. The high Ca2+ level in the ER lumen and low cytosolic concentration is needed for Ca2+-based intracellular signaling, for synaptic signaling and Ca2+ waves, and for preparing proteins for correct folding in the presence of high Ca2+ concentrations to cope with the high concentrations of extracellular milieu. Particularly, ER Ca2+ is controlled in axodendritic areas for proper neurito- and synaptogenesis and synaptic plasticity and remodeling. In this review, we cover the physiologic functions of the neuronal ER and discuss it in context of common neurodegenerative diseases, focusing on pharmacological regulation of ER Ca2+ Furthermore, we postulate that heterogeneity of the ER, its protein folding capacity, and ensuring Ca2+ regulation are crucial factors for the aging and selective vulnerability of neurons in various neurodegenerative diseases. SIGNIFICANCE STATEMENT: Endoplasmic reticulum (ER) Ca2+ regulators are promising therapeutic targets for degenerative diseases for which efficacious drug therapies do not exist. The use of pharmacological probes targeting maintenance and restoration of ER Ca2+ can provide restoration of protein homeostasis (e.g., folding of complex plasma membrane signaling receptors) and slow down the degeneration process of neurons.
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Affiliation(s)
- Ilmari Parkkinen
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Anna Their
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Muhammad Yasir Asghar
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Sreesha Sree
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Mikko Airavaara
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
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10
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Hildebrandt RP, Moss KR, Janusz-Kaminska A, Knudson LA, Denes LT, Saxena T, Boggupalli DP, Li Z, Lin K, Bassell GJ, Wang ET. Muscleblind-like proteins use modular domains to localize RNAs by riding kinesins and docking to membranes. Nat Commun 2023; 14:3427. [PMID: 37296096 PMCID: PMC10256740 DOI: 10.1038/s41467-023-38923-6] [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: 08/23/2022] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
RNA binding proteins (RBPs) act as critical facilitators of spatially regulated gene expression. Muscleblind-like (MBNL) proteins, implicated in myotonic dystrophy and cancer, localize RNAs to myoblast membranes and neurites through unknown mechanisms. We find that MBNL forms motile and anchored granules in neurons and myoblasts, and selectively associates with kinesins Kif1bα and Kif1c through its zinc finger (ZnF) domains. Other RBPs with similar ZnFs associate with these kinesins, implicating a motor-RBP specificity code. MBNL and kinesin perturbation leads to widespread mRNA mis-localization, including depletion of Nucleolin transcripts from neurites. Live cell imaging and fractionation reveal that the unstructured carboxy-terminal tail of MBNL1 allows for anchoring at membranes. An approach, termed RBP Module Recruitment and Imaging (RBP-MRI), reconstitutes kinesin- and membrane-recruitment functions using MBNL-MS2 coat protein fusions. Our findings decouple kinesin association, RNA binding, and membrane anchoring functions of MBNL while establishing general strategies for studying multi-functional, modular domains of RBPs.
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Affiliation(s)
- Ryan P Hildebrandt
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kathryn R Moss
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Luke A Knudson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Lance T Denes
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Tanvi Saxena
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Devi Prasad Boggupalli
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Zhuangyue Li
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kun Lin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Eric T Wang
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
- Myology Institute, University of Florida, Gainesville, FL, USA.
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11
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Oudart M, Avila-Gutierrez K, Moch C, Dossi E, Milior G, Boulay AC, Gaudey M, Moulard J, Lombard B, Loew D, Bemelmans AP, Rouach N, Chapat C, Cohen-Salmon M. The ribosome-associated protein RACK1 represses Kir4.1 translation in astrocytes and influences neuronal activity. Cell Rep 2023; 42:112456. [PMID: 37126448 DOI: 10.1016/j.celrep.2023.112456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 02/10/2023] [Accepted: 04/16/2023] [Indexed: 05/02/2023] Open
Abstract
The regulation of translation in astrocytes, the main glial cells in the brain, remains poorly characterized. We developed a high-throughput proteomics screen for polysome-associated proteins in astrocytes and focused on ribosomal protein receptor of activated protein C kinase 1 (RACK1), a critical factor in translational regulation. In astrocyte somata and perisynaptic astrocytic processes (PAPs), RACK1 preferentially binds to a number of mRNAs, including Kcnj10, encoding the inward-rectifying potassium (K+) channel Kir4.1. By developing an astrocyte-specific, conditional RACK1 knockout mouse model, we show that RACK1 represses production of Kir4.1 in hippocampal astrocytes and PAPs. Upregulation of Kir4.1 in the absence of RACK1 increases astrocytic Kir4.1-mediated K+ currents and volume. It also modifies neuronal activity attenuating burst frequency and duration. Reporter-based assays reveal that RACK1 controls Kcnj10 translation through the transcript's 5' untranslated region. Hence, translational regulation by RACK1 in astrocytes represses Kir4.1 expression and influences neuronal activity.
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Affiliation(s)
- Marc Oudart
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katia Avila-Gutierrez
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clara Moch
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Elena Dossi
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Giampaolo Milior
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Mathis Gaudey
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Bérangère Lombard
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Damarys Loew
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Alexis-Pierre Bemelmans
- CEA, Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clément Chapat
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France.
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12
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Ghane MA, Wei W, Yakout DW, Allen ZD, Miller CL, Dong B, Yang JJ, Fang N, Mabb AM. Arc ubiquitination regulates endoplasmic reticulum-mediated Ca 2+ release and CaMKII signaling. Front Cell Neurosci 2023; 17:1091324. [PMID: 36998269 PMCID: PMC10043188 DOI: 10.3389/fncel.2023.1091324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
Synaptic plasticity relies on rapid, yet spatially precise signaling to alter synaptic strength. Arc is a brain enriched protein that is rapidly expressed during learning-related behaviors and is essential for regulating metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD). We previously showed that disrupting the ubiquitination capacity of Arc enhances mGluR-LTD; however, the consequences of Arc ubiquitination on other mGluR-mediated signaling events is poorly characterized. Here we find that pharmacological activation of Group I mGluRs with S-3,5-dihydroxyphenylglycine (DHPG) increases Ca2+ release from the endoplasmic reticulum (ER). Disrupting Arc ubiquitination on key amino acid residues enhances DHPG-induced ER-mediated Ca2+ release. These alterations were observed in all neuronal subregions except secondary branchpoints. Deficits in Arc ubiquitination altered Arc self-assembly and enhanced its interaction with calcium/calmodulin-dependent protein kinase IIb (CaMKIIb) and constitutively active forms of CaMKII in HEK293 cells. Colocalization of Arc and CaMKII was altered in cultured hippocampal neurons, with the notable exception of secondary branchpoints. Finally, disruptions in Arc ubiquitination were found to increase Arc interaction with the integral ER protein Calnexin. These results suggest a previously unknown role for Arc ubiquitination in the fine tuning of ER-mediated Ca2+ signaling that may support mGluR-LTD, which in turn, may regulate CaMKII and its interactions with Arc.
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Affiliation(s)
- Mohammad A. Ghane
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Wei Wei
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Dina W. Yakout
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Zachary D. Allen
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Cassandra L. Miller
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Jenny J. Yang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
- Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, United States
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Angela M. Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
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13
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Campbell EP, Abushawish AA, Valdez LA, Bell MK, Haryono M, Rangamani P, Bloodgood BL. Electrical signals in the ER are cell type and stimulus specific with extreme spatial compartmentalization in neurons. Cell Rep 2023; 42:111943. [PMID: 36640310 PMCID: PMC10033362 DOI: 10.1016/j.celrep.2022.111943] [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: 01/12/2022] [Revised: 10/04/2022] [Accepted: 12/15/2022] [Indexed: 01/06/2023] Open
Abstract
The endoplasmic reticulum (ER) is a tortuous organelle that spans throughout a cell with a continuous membrane containing ion channels, pumps, and transporters. It is unclear if stimuli that gate ER ion channels trigger substantial membrane potential fluctuations and if those fluctuations spread beyond their site of origin. Here, we visualize ER membrane potential dynamics in HEK cells and cultured rat hippocampal neurons by targeting a genetically encoded voltage indicator specifically to the ER membrane. We report the existence of clear cell-type- and stimulus-specific ER membrane potential fluctuations. In neurons, direct stimulation of ER ryanodine receptors generates depolarizations that scale linearly with stimulus strength and reach tens of millivolts. However, ER potentials do not spread beyond the site of receptor activation, exhibiting steep attenuation that is exacerbated by intracellular large conductance K+ channels. Thus, segments of ER can generate large depolarizations that are actively restricted from impacting nearby, contiguous membrane.
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Affiliation(s)
- Evan P Campbell
- Neurobiology Department, School of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ahmed A Abushawish
- Neurobiology Department, School of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Lauren A Valdez
- Neurobiology Department, School of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Miriam K Bell
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Melita Haryono
- Neurobiology Department, School of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Brenda L Bloodgood
- Neurobiology Department, School of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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14
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Konietzny A, Wegmann S, Mikhaylova M. The endoplasmic reticulum puts a new spin on synaptic tagging. Trends Neurosci 2023; 46:32-44. [PMID: 36428191 DOI: 10.1016/j.tins.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/12/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
Abstract
The heterogeneity of the endoplasmic reticulum (ER) makes it a versatile platform for a broad range of homeostatic processes, ranging from calcium regulation to synthesis and trafficking of proteins and lipids. It is not surprising that neurons use this organelle to fine-tune synaptic properties and thereby provide specificity to synaptic inputs. In this review, we discuss the mechanisms that enable activity-dependent ER recruitment into dendritic spines, with a focus on molecular mechanisms that mediate transport and retention of the ER in spines. The role of calcium signaling in spine ER, synaptopodin 'tagging' of active synapses, and the formation of the spine apparatus (SA) are highlighted. Finally, we discuss the role of liquid-liquid phase separation as a possible driving force in these processes.
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Affiliation(s)
- Anja Konietzny
- AG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin, Germany; Guest Group 'Neuronal Protein Transport', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Wegmann
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Marina Mikhaylova
- AG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin, Germany; Guest Group 'Neuronal Protein Transport', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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15
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Shishkova EA, Kraev IV, Rogachevsky VV. Evaluation of Oolong Tea Extract Staining of Brain Tissue with Special Reference to Smooth Endoplasmic Reticulum. Biophysics (Nagoya-shi) 2022. [DOI: 10.1134/s0006350922050177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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16
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Kemal S, Richardson HS, Dyne ED, Fu MM. ER and Golgi trafficking in axons, dendrites, and glial processes. Curr Opin Cell Biol 2022; 78:102119. [PMID: 35964523 PMCID: PMC9590103 DOI: 10.1016/j.ceb.2022.102119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 01/31/2023]
Abstract
Both neurons and glia in mammalian brains are highly ramified. Neurons form complex neural networks using axons and dendrites. Axons are long with few branches and form pre-synaptic boutons that connect to target neurons and effector tissues. Dendrites are shorter, highly branched, and form post-synaptic boutons. Astrocyte processes contact synapses and blood vessels in order to regulate neuronal activity and blood flow, respectively. Oligodendrocyte processes extend toward axons to make myelin sheaths. Microglia processes dynamically survey their environments. Here, we describe the local secretory system (ER and Golgi) in neuronal and glial processes. We focus on Golgi outpost functions in acentrosomal microtubule nucleation, cargo trafficking, and protein glycosylation. Thus, satellite ER and Golgi are critical for local structure and function in neurons and glia.
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Affiliation(s)
- Shahrnaz Kemal
- NINDS (National Institute of Neurological Disorders and Stroke), National Institutes of Health, Bethesda, MD 20893, USA
| | - Hunter S Richardson
- NINDS (National Institute of Neurological Disorders and Stroke), National Institutes of Health, Bethesda, MD 20893, USA
| | - Eric D Dyne
- NINDS (National Institute of Neurological Disorders and Stroke), National Institutes of Health, Bethesda, MD 20893, USA
| | - Meng-Meng Fu
- NINDS (National Institute of Neurological Disorders and Stroke), National Institutes of Health, Bethesda, MD 20893, USA.
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17
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Transport-dependent maturation of organelles in neurons. Curr Opin Cell Biol 2022; 78:102121. [PMID: 36030563 DOI: 10.1016/j.ceb.2022.102121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/15/2022] [Indexed: 01/31/2023]
Abstract
Some organelles show a spatial gradient of maturation along the neuronal process where more mature organelles are found closer to the cell body. This gradient is set up by progressive maturation steps that are aided by differential organelle distribution as well as transport. Autophagosomes and endosomes mature as they acquire lysosomal membrane proteins and decrease their luminal pH as they are retrogradely transported towards the cell body. The acquisition of lysosomal proteins along the neuronal processes likely occurs through fusion or membrane exchange events with Golgi-derived donor transport carriers that are transported anterogradely from the cell body. The mechanisms by which endosomes and autophagosomes mature might be applicable to other organelles that are transported along neuronal processes. Defects in axonal transport may also contribute to the accumulation of immature organelles in neurons. Such accumulations have been seen in neurons of neurodegenerative models.
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18
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Getz AM, Ducros M, Breillat C, Lampin-Saint-Amaux A, Daburon S, François U, Nowacka A, Fernández-Monreal M, Hosy E, Lanore F, Zieger HL, Sainlos M, Humeau Y, Choquet D. High-resolution imaging and manipulation of endogenous AMPA receptor surface mobility during synaptic plasticity and learning. SCIENCE ADVANCES 2022; 8:eabm5298. [PMID: 35895810 PMCID: PMC9328687 DOI: 10.1126/sciadv.abm5298] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 06/10/2022] [Indexed: 05/18/2023]
Abstract
Regulation of synaptic neurotransmitter receptor content is a fundamental mechanism for tuning synaptic efficacy during experience-dependent plasticity and behavioral adaptation. However, experimental approaches to track and modify receptor movements in integrated experimental systems are limited. Exploiting AMPA-type glutamate receptors (AMPARs) as a model, we generated a knock-in mouse expressing the biotin acceptor peptide (AP) tag on the GluA2 extracellular N-terminal. Cell-specific introduction of biotin ligase allows the use of monovalent or tetravalent avidin variants to respectively monitor or manipulate the surface mobility of endogenous AMPAR containing biotinylated AP-GluA2 in neuronal subsets. AMPAR immobilization precluded the expression of long-term potentiation and formation of contextual fear memory, allowing target-specific control of the expression of synaptic plasticity and animal behavior. The AP tag knock-in model offers unprecedented access to resolve and control the spatiotemporal dynamics of endogenous receptors, and opens new avenues to study the molecular mechanisms of synaptic plasticity and learning.
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Affiliation(s)
- Angela M. Getz
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Mathieu Ducros
- Université de Bordeaux, CNRS, INSERM, Bordeaux Imaging Center (BIC), UAR 3420, US 4, F-33000 Bordeaux, France
| | - Christelle Breillat
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Aurélie Lampin-Saint-Amaux
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Sophie Daburon
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Urielle François
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Agata Nowacka
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Mónica Fernández-Monreal
- Université de Bordeaux, CNRS, INSERM, Bordeaux Imaging Center (BIC), UAR 3420, US 4, F-33000 Bordeaux, France
| | - Eric Hosy
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Frédéric Lanore
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Hanna L. Zieger
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Matthieu Sainlos
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Yann Humeau
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
| | - Daniel Choquet
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience (IINS), UMR 5297, F-33000 Bordeaux, France
- Université de Bordeaux, CNRS, INSERM, Bordeaux Imaging Center (BIC), UAR 3420, US 4, F-33000 Bordeaux, France
- Corresponding author.
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19
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Khan S. Endoplasmic Reticulum in Metaplasticity: From Information Processing to Synaptic Proteostasis. Mol Neurobiol 2022; 59:5630-5655. [PMID: 35739409 DOI: 10.1007/s12035-022-02916-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 06/05/2022] [Indexed: 11/29/2022]
Abstract
The ER (endoplasmic reticulum) is a Ca2+ reservoir and the unique protein-synthesizing machinery which is distributed throughout the neuron and composed of multiple different structural domains. One such domain is called EMC (endoplasmic reticulum membrane protein complex), pleiotropic nature in cellular functions. The ER/EMC position inside the neurons unmasks its contribution to synaptic plasticity via regulating various cellular processes from protein synthesis to Ca2+ signaling. Since presynaptic Ca2+ channels and postsynaptic ionotropic receptors are organized into the nanodomains, thus ER can be a crucial player in establishing TMNCs (transsynaptic molecular nanocolumns) to shape efficient neural communications. This review hypothesized that ER is not only involved in stress-mediated neurodegeneration but also axon regrowth, remyelination, neurotransmitter switching, information processing, and regulation of pre- and post-synaptic functions. Thus ER might not only be a protein-synthesizing and quality control machinery but also orchestrates plasticity of plasticity (metaplasticity) within the neuron to execute higher-order brain functions and neural repair.
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Affiliation(s)
- Shumsuzzaman Khan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
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20
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Zamponi E, Meehl JB, Voeltz GK. The ER ladder is a unique morphological feature of developing mammalian axons. Dev Cell 2022; 57:1369-1382.e6. [PMID: 35609616 DOI: 10.1016/j.devcel.2022.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/28/2022] [Accepted: 05/02/2022] [Indexed: 11/25/2022]
Abstract
The endoplasmic reticulum (ER) confronts a challenge to accommodate long, smooth ER tubules into the structural complexity of the axonal compartment. Here, we describe a morphological feature for the axonal ER network in developing neurons we termed the ER ladder. Axonal ER ladders are composed of rungs that wrap tightly around the microtubule bundle and dynamic rails, which slide across microtubules. We found that the ER-shaping protein Reticulon 2 determines the architecture and dynamics of the axonal ER ladder by modulating its interaction with microtubules. Moreover, we show that ER ladder depletion impairs the trafficking of associated vesicular axonal cargoes. Finally, we demonstrate that stromal interaction molecule 1 (Stim1) localizes to ER rungs and translocates to ER-plasma membrane contact sites upon depletion of luminal Ca2+. Our findings uncover fundamental insights into the structural and functional organization of the axonal ER network in developing mammalian neurons.
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Affiliation(s)
- Emiliano Zamponi
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA
| | - Janet B Meehl
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA
| | - Gia K Voeltz
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA.
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21
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Harris KM, Hubbard DD, Kuwajima M, Abraham WC, Bourne JN, Bowden JB, Haessly A, Mendenhall JM, Parker PH, Shi B, Spacek J. Dendritic Spine Density Scales with Microtubule Number in Rat Hippocampal Dendrites. Neuroscience 2022; 489:84-97. [PMID: 35218884 PMCID: PMC9038701 DOI: 10.1016/j.neuroscience.2022.02.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 12/14/2022]
Abstract
Microtubules deliver essential resources to and from synapses. Three-dimensional reconstructions in rat hippocampus reveal a sampling bias regarding spine density that needs to be controlled for dendrite caliber and resource delivery based on microtubule number. The strength of this relationship varies across dendritic arbors, as illustrated for area CA1 and dentate gyrus. In both regions, proximal dendrites had more microtubules than distal dendrites. For CA1 pyramidal cells, spine density was greater on thicker than thinner dendrites in stratum radiatum, or on the more uniformly thin terminal dendrites in stratum lacunosum moleculare. In contrast, spine density was constant across the cone shaped arbor of tapering dendrites from dentate granule cells. These differences suggest that thicker dendrites supply microtubules to subsequent dendritic branches and local dendritic spines, whereas microtubules in thinner dendrites need only provide resources to local spines. Most microtubules ran parallel to dendrite length and associated with long, presumably stable mitochondria, which occasionally branched into lateral dendritic branches. Short, presumably mobile, mitochondria were tethered to microtubules that bent and appeared to direct them into a thin lateral branch. Prior work showed that dendritic segments with the same number of microtubules had elevated resources in subregions of their dendritic shafts where spine synapses had enlarged, and spine clusters had formed. Thus, additional microtubules were not required for redistribution of resources locally to growing spines or synapses. These results provide new understanding about the potential for microtubules to regulate resource delivery to and from dendritic branches and locally among dendritic spines.
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Affiliation(s)
- Kristen M Harris
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States.
| | - Dusten D Hubbard
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Masaaki Kuwajima
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Wickliffe C Abraham
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Jennifer N Bourne
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Jared B Bowden
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Andrea Haessly
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - John M Mendenhall
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Patrick H Parker
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Bitao Shi
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
| | - Josef Spacek
- Department of Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, TX, United States
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22
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Chanaday NL, Kavalali ET. Role of the endoplasmic reticulum in synaptic transmission. Curr Opin Neurobiol 2022; 73:102538. [PMID: 35395547 PMCID: PMC9167765 DOI: 10.1016/j.conb.2022.102538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/25/2022] [Accepted: 03/06/2022] [Indexed: 11/03/2022]
Abstract
Neurons possess a complex morphology spanning long distances and a large number of subcellular specializations such as presynaptic terminals and dendritic spines. This structural complexity is essential for maintenance of synaptic junctions and associated electrical as well as biochemical signaling events. Given the structural and functional complexity of neurons, neuronal endoplasmic reticulum is emerging as a key regulator of neuronal function, in particular synaptic signaling. Neuronal endoplasmic reticulum mediates calcium signaling, calcium and lipid homeostasis, vesicular trafficking, and proteostasis events that underlie autonomous functions of numerous subcellular compartments. However, based on its geometric complexity spanning the whole neuron, endoplasmic reticulum also integrates the activity of these autonomous compartments across the neuron and coordinates their interactions with the soma. In this article, we review recent work regarding neuronal endoplasmic reticulum function and its relationship to neurotransmission and plasticity.
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Affiliation(s)
- Natali L Chanaday
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, 37240-7933, USA.
| | - Ege T Kavalali
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA.
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23
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Nedozralova H, Basnet N, Ibiricu I, Bodakuntla S, Biertümpfel C, Mizuno N. In situ cryo-electron tomography reveals local cellular machineries for axon branch development. J Biophys Biochem Cytol 2022; 221:213057. [PMID: 35262630 PMCID: PMC8916118 DOI: 10.1083/jcb.202106086] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 11/23/2021] [Accepted: 01/31/2022] [Indexed: 01/02/2023] Open
Abstract
Neurons are highly polarized cells forming an intricate network of dendrites and axons. They are shaped by the dynamic reorganization of cytoskeleton components and cellular organelles. Axon branching allows the formation of new paths and increases circuit complexity. However, our understanding of branch formation is sparse due to the lack of direct in-depth observations. Using in situ cellular cryo-electron tomography on primary mouse neurons, we directly visualized the remodeling of organelles and cytoskeleton structures at axon branches. Strikingly, branched areas functioned as hotspots concentrating organelles to support dynamic activities. Unaligned actin filaments assembled at the base of premature branches accompanied by filopodia-like protrusions. Microtubules and ER comigrated into preformed branches to support outgrowth together with accumulating compact, ∼500-nm mitochondria and locally clustered ribosomes. We obtained a roadmap of events supporting the hypothesis of local protein synthesis selectively taking place at axon branches, allowing them to serve as unique control hubs for axon development and downstream neural network formation.
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Affiliation(s)
- Hana Nedozralova
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.,Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Nirakar Basnet
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Iosune Ibiricu
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Satish Bodakuntla
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Christian Biertümpfel
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Naoko Mizuno
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD.,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD
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24
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Grochowska KM, Andres‐Alonso M, Karpova A, Kreutz MR. The needs of a synapse—How local organelles serve synaptic proteostasis. EMBO J 2022; 41:e110057. [PMID: 35285533 PMCID: PMC8982616 DOI: 10.15252/embj.2021110057] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 12/12/2022] Open
Abstract
Synaptic function crucially relies on the constant supply and removal of neuronal membranes. The morphological complexity of neurons poses a significant challenge for neuronal protein transport since the machineries for protein synthesis and degradation are mainly localized in the cell soma. In response to this unique challenge, local micro‐secretory systems have evolved that are adapted to the requirements of neuronal membrane protein proteostasis. However, our knowledge of how neuronal proteins are synthesized, trafficked to membranes, and eventually replaced and degraded remains scarce. Here, we review recent insights into membrane trafficking at synaptic sites and into the contribution of local organelles and micro‐secretory pathways to synaptic function. We describe the role of endoplasmic reticulum specializations in neurons, Golgi‐related organelles, and protein complexes like retromer in the synthesis and trafficking of synaptic transmembrane proteins. We discuss the contribution of autophagy and of proteasome‐mediated and endo‐lysosomal degradation to presynaptic proteostasis and synaptic function, as well as nondegradative roles of autophagosomes and lysosomes in signaling and synapse remodeling. We conclude that the complexity of neuronal cyto‐architecture necessitates long‐distance protein transport that combines degradation with signaling functions.
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Affiliation(s)
- Katarzyna M Grochowska
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
| | - Maria Andres‐Alonso
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
| | - Anna Karpova
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
- Center for Behavioral Brain Sciences Otto von Guericke University Magdeburg Germany
| | - Michael R Kreutz
- Leibniz Group “Dendritic Organelles and Synaptic Function” Center for Molecular Neurobiology ZMNH University Medical Center Hamburg‐Eppendorf Hamburg Germany
- Research Group Neuroplasticity Leibniz Institute for Neurobiology Magdeburg Germany
- Center for Behavioral Brain Sciences Otto von Guericke University Magdeburg Germany
- German Center for Neurodegenerative Diseases (DZNE) Magdeburg Germany
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25
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Dastidar SG, Nair D. A Ribosomal Perspective on Neuronal Local Protein Synthesis. Front Mol Neurosci 2022; 15:823135. [PMID: 35283723 PMCID: PMC8904363 DOI: 10.3389/fnmol.2022.823135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/17/2022] [Indexed: 11/15/2022] Open
Abstract
Continued mRNA translation and protein production are critical for various neuronal functions. In addition to the precise sorting of proteins from cell soma to distant locations, protein synthesis allows a dynamic remodeling of the local proteome in a spatially variable manner. This spatial heterogeneity of protein synthesis is shaped by several factors such as injury, guidance cues, developmental cues, neuromodulators, and synaptic activity. In matured neurons, thousands of synapses are non-uniformly distributed throughout the dendritic arbor. At any given moment, the activity of individual synapses varies over a wide range, giving rise to the variability in protein synthesis. While past studies have primarily focused on the translation factors or the identity of translated mRNAs to explain the source of this variation, the role of ribosomes in this regard continues to remain unclear. Here, we discuss how several stochastic mechanisms modulate ribosomal functions, contributing to the variability in neuronal protein expression. Also, we point out several underexplored factors such as local ion concentration, availability of tRNA or ATP during translation, and molecular composition and organization of a compartment that can influence protein synthesis and its variability in neurons.
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26
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Nourbakhsh K, Ferreccio AA, Bernard MJ, Yadav S. TAOK2 is an ER-localized kinase that catalyzes the dynamic tethering of ER to microtubules. Dev Cell 2021; 56:3321-3333.e5. [PMID: 34879262 PMCID: PMC8699727 DOI: 10.1016/j.devcel.2021.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 09/17/2021] [Accepted: 11/15/2021] [Indexed: 01/07/2023]
Abstract
The endoplasmic reticulum (ER) depends on extensive association with the microtubule (MT) cytoskeleton for its structure and mitotic inheritance. However, mechanisms that underlie coupling of ER membranes to MTs are poorly understood. We have identified thousand and one amino acid kinase 2 (TAOK2) as a pleiotropic protein kinase that mediates tethering of ER to MTs. In human cells, TAOK2 localizes in distinct ER subdomains via transmembrane helices and an adjacent amphipathic region. Through its C-terminal tail, TAOK2 directly binds MTs, coupling ER membranes to the MT cytoskeleton. In TAOK2 knockout cells, although ER-membrane dynamics are increased, movement of ER along growing MT plus ends is disrupted. ER-MT tethering is tightly regulated by catalytic activity of TAOK2, perturbation of which leads to defects in ER morphology, association with MTs, and cell division. Our study identifies TAOK2 as an ER-MT tether and reveals a kinase-regulated mechanism for control of ER dynamics.
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Affiliation(s)
- Kimya Nourbakhsh
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Amy A Ferreccio
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Matthew J Bernard
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Smita Yadav
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Institute of Stem Cell and Regenerative Medicine, Seattle, WA 98109, USA.
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27
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Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
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28
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Tran NH, Carter SD, De Mazière A, Ashkenazi A, Klumperman J, Walter P, Jensen GJ. The stress-sensing domain of activated IRE1α forms helical filaments in narrow ER membrane tubes. Science 2021; 374:52-57. [PMID: 34591618 PMCID: PMC9041316 DOI: 10.1126/science.abh2474] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The signaling network of the unfolded protein response (UPR) adjusts the protein-folding capacity of the endoplasmic reticulum (ER) according to need. The most conserved UPR sensor, IRE1α, spans the ER membrane and activates through oligomerization. IRE1α oligomers accumulate in dynamic foci. We determined the in situ structure of IRE1α foci by cryogenic correlated light and electron microscopy combined with electron cryo-tomography and complementary immuno–electron microscopy in mammalian cell lines. IRE1α foci localized to a network of narrow anastomosing ER tubes (diameter, ~28 nm) with complex branching. The lumen of the tubes contained protein filaments, which were likely composed of arrays of IRE1α lumenal domain dimers that were arranged in two intertwined, left-handed helices. This specialized ER subdomain may play a role in modulating IRE1α signaling.
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Affiliation(s)
- Ngoc-Han Tran
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Stephen D. Carter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ann De Mazière
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, Netherlands
| | - Avi Ashkenazi
- Cancer Immunology, Genentech, Inc., South San Francisco, CA, USA
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, Netherlands
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Grant J. Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
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29
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Sun J, Harion R, Naito T, Saheki Y. INPP5K and Atlastin-1 maintain the nonuniform distribution of ER-plasma membrane contacts in neurons. Life Sci Alliance 2021; 4:4/11/e202101092. [PMID: 34556534 PMCID: PMC8507493 DOI: 10.26508/lsa.202101092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/03/2021] [Accepted: 09/11/2021] [Indexed: 02/04/2023] Open
Abstract
In neurons, the ER extends throughout all cellular processes, forming multiple contacts with the plasma membrane (PM) to fine-tune neuronal physiology. However, the mechanisms that regulate the distribution of neuronal ER-PM contacts are not known. Here, we used the Caenorhabditis elegans DA9 motor neuron as our model system and found that neuronal ER-PM contacts are enriched in soma and dendrite and mostly absent in axons. Using forward genetic screen, we identified that the inositol 5-phosphatase, CIL-1 (human INPP5K), and the dynamin-like GTPase, ATLN-1 (human Atlastin-1), help to maintain the non-uniform, somatodendritic enrichment of neuronal ER-PM contacts. Mechanistically, CIL-1 acts upstream of ATLN-1 to maintain the balance between ER tubules and sheets. In mutants of CIL-1 or ATLN-1, ER sheets expand and invade into the axon. This is accompanied by the ectopic formation of axonal ER-PM contacts and defects in axon regeneration following laser-induced axotomy. As INPP5K and Atlastin-1 have been linked to neurological disorders, the unique distribution of neuronal ER-PM contacts maintained by these proteins may support neuronal resilience during the onset and progression of these diseases.
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Affiliation(s)
- Jingbo Sun
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Raihanah Harion
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Tomoki Naito
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore .,Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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30
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A MATLAB-based program for three-dimensional quantitative analysis of micronuclei reveals that neuroinflammation induces micronuclei formation in the brain. Sci Rep 2021; 11:18360. [PMID: 34526560 PMCID: PMC8443747 DOI: 10.1038/s41598-021-97640-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/25/2021] [Indexed: 11/22/2022] Open
Abstract
The micronucleus is known to be a biomarker for genomic instability, which is a hallmark of tumors and aging. Normally, micronuclei are produced by segregation errors and mechanical stresses arising from dividing or migrating cells, leading to activation of the innate immune response pathway. Although micronuclei often emerge in damaged tissues, the quantitative procedure for analyzing micronuclei accurately has been problematic. Here, we introduce a novel MATLAB-based program for quantifying micronuclei (CAMDi: calculating automatic micronuclei distinction) in vitro and in vivo. CAMDi is adaptable to various experimental imaging techniques and is useful for obtaining reproducible data. CAMDi enables us to measure the accurate size of micronuclei from the three-dimensional images. Using CAMDi, we revealed a novel link between the emergence of micronuclei and neuroinflammation. We found that inflammatory stimulation does not increase the number of micronuclei in primary neurons. On the other hand, the administration of lipopolysaccharide into mice slightly increases micronuclei formation in neurons of the hippocampus region. These findings demonstrate that neuronal micronuclei formations are induced by an inflammatory response in a non-cell-autonomous manner. We provide a novel tool, CAMDi, to quantify micronuclei and demonstrate that neuronal micronuclei are produced not only by the cell-autonomous process but also by the intercellular communication associated with neuroinflammation in vivo.
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31
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Chao JT, Pina F, Niwa M. Regulation of the early stages of endoplasmic reticulum inheritance during ER stress. Mol Biol Cell 2021; 32:109-119. [PMID: 33448894 PMCID: PMC8120693 DOI: 10.1091/mbc.e20-08-0558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The endoplasmic reticulum (ER) is one of the largest cytoplasmic organelles in eukaryotic cells and plays a role in many cellular processes, such as the production and quality control of secretory protein, lipid synthesis, and calcium homeostasis. The ER cannot be generated de novo, and thus its proper inheritance during cell division is paramount to the health and survival of the daughter cells. Although previous work has uncovered the cytoskeletal components involved, we still lack a comprehensive understanding of the intricate steps of and the cytoplasmic and membrane-bound components involved in ER inheritance. To directly address these issues, we utilized microfluidics and genetic analyses to show that before nuclear migration, early ER inheritance can be further divided into three distinctive steps. Moreover, we demonstrated that perturbing each of these steps affects the cell's ability to mitigate ER stress. Thus, proper ER inheritance is essential to ensuring a healthy, functional cell.
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Affiliation(s)
- Jesse T Chao
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0377.,Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Francisco Pina
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0377.,Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0377
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32
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Özkan N, Koppers M, van Soest I, van Harten A, Jurriens D, Liv N, Klumperman J, Kapitein LC, Hoogenraad CC, Farías GG. ER - lysosome contacts at a pre-axonal region regulate axonal lysosome availability. Nat Commun 2021; 12:4493. [PMID: 34301956 PMCID: PMC8302662 DOI: 10.1038/s41467-021-24713-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
Neuronal function relies on careful coordination of organelle organization and transport. Kinesin-1 mediates transport of the endoplasmic reticulum (ER) and lysosomes into the axon and it is increasingly recognized that contacts between the ER and lysosomes influence organelle organization. However, it is unclear how organelle organization, inter-organelle communication and transport are linked and how this contributes to local organelle availability in neurons. Here, we show that somatic ER tubules are required for proper lysosome transport into the axon. Somatic ER tubule disruption causes accumulation of enlarged and less motile lysosomes at the soma. ER tubules regulate lysosome size and axonal translocation by promoting lysosome homo-fission. ER tubule - lysosome contacts often occur at a somatic pre-axonal region, where the kinesin-1-binding ER-protein P180 binds microtubules to promote kinesin-1-powered lysosome fission and subsequent axonal translocation. We propose that ER tubule - lysosome contacts at a pre-axonal region finely orchestrate axonal lysosome availability for proper neuronal function.
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Affiliation(s)
- Nazmiye Özkan
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Max Koppers
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Inge van Soest
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Alexandra van Harten
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Daphne Jurriens
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Nalan Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ginny G Farías
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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33
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Rajgor D, Welle TM, Smith KR. The Coordination of Local Translation, Membranous Organelle Trafficking, and Synaptic Plasticity in Neurons. Front Cell Dev Biol 2021; 9:711446. [PMID: 34336865 PMCID: PMC8317219 DOI: 10.3389/fcell.2021.711446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Neurons are highly complex polarized cells, displaying an extraordinary degree of spatial compartmentalization. At presynaptic and postsynaptic sites, far from the cell body, local protein synthesis is utilized to continually modify the synaptic proteome, enabling rapid changes in protein production to support synaptic function. Synapses undergo diverse forms of plasticity, resulting in long-term, persistent changes in synapse strength, which are paramount for learning, memory, and cognition. It is now well-established that local translation of numerous synaptic proteins is essential for many forms of synaptic plasticity, and much work has gone into deciphering the strategies that neurons use to regulate activity-dependent protein synthesis. Recent studies have pointed to a coordination of the local mRNA translation required for synaptic plasticity and the trafficking of membranous organelles in neurons. This includes the co-trafficking of RNAs to their site of action using endosome/lysosome “transports,” the regulation of activity-dependent translation at synapses, and the role of mitochondria in fueling synaptic translation. Here, we review our current understanding of these mechanisms that impact local translation during synaptic plasticity, providing an overview of these novel and nuanced regulatory processes involving membranous organelles in neurons.
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Affiliation(s)
- Dipen Rajgor
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Theresa M Welle
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
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34
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Bourke AM, Schwartz SL, Bowen AB, Kleinjan MS, Winborn CS, Kareemo DJ, Gutnick A, Schwarz TL, Kennedy MJ. zapERtrap: A light-regulated ER release system reveals unexpected neuronal trafficking pathways. J Cell Biol 2021; 220:212461. [PMID: 34241635 PMCID: PMC8276314 DOI: 10.1083/jcb.202103186] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 05/31/2021] [Accepted: 06/21/2021] [Indexed: 12/29/2022] Open
Abstract
Here we introduce zapalog-mediated endoplasmic reticulum trap (zapERtrap), which allows one to use light to precisely trigger forward trafficking of diverse integral membrane proteins from internal secretory organelles to the cell surface with single cell and subcellular spatial resolution. To demonstrate its utility, we use zapERtrap in neurons to dissect where synaptic proteins emerge at the cell surface when processed through central (cell body) or remote (dendrites) secretory pathways. We reveal rapid and direct long-range trafficking of centrally processed proteins deep into the dendritic arbor to synaptic sites. Select proteins were also trafficked to the plasma membrane of the axon initial segment, revealing a novel surface trafficking hotspot. Proteins locally processed through dendritic secretory networks were widely dispersed before surface insertion, challenging assumptions for precise trafficking at remote sites. These experiments provide new insights into compartmentalized secretory trafficking and showcase the tunability and spatiotemporal control of zapERtrap, which will have broad applications for regulating cell signaling and function.
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Affiliation(s)
- Ashley M Bourke
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Samantha L Schwartz
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Aaron B Bowen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Mason S Kleinjan
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Christina S Winborn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Dean J Kareemo
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
| | - Amos Gutnick
- Department of Neurobiology, Harvard Medical School, Boston, MA
| | - Thomas L Schwarz
- Department of Neurobiology, Harvard Medical School, Boston, MA.,F.M. Kirby Neurobiology Center, Children's Hospital, Boston, MA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO
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Fabbretti E, Antognolli G, Tongiorgi E. Amyloid-β Impairs Dendritic Trafficking of Golgi-Like Organelles in the Early Phase Preceding Neurite Atrophy: Rescue by Mirtazapine. Front Mol Neurosci 2021; 14:661728. [PMID: 34149353 PMCID: PMC8209480 DOI: 10.3389/fnmol.2021.661728] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/30/2021] [Indexed: 12/20/2022] Open
Abstract
Neurite atrophy with loss of neuronal polarity is a pathological hallmark of Alzheimer's disease (AD) and other neurological disorders. While there is substantial agreement that disruption of intracellular vesicle trafficking is associated with axonal pathology in AD, comparatively less is known regarding its role in dendritic atrophy. This is a significant gap of knowledge because, unlike axons, dendrites are endowed with the complete endomembrane system comprising endoplasmic reticulum (ER), ER-Golgi intermediate compartment (ERGIC), Golgi apparatus, post-Golgi vesicles, and a recycling-degradative route. In this study, using live-imaging of pGOLT-expressing vesicles, indicative of Golgi outposts and satellites, we investigate how amyloid-β (Aβ) oligomers affect the trafficking of Golgi-like organelles in the different dendritic compartments of cultured rat hippocampal neurons. We found that short-term (4 h) treatment with Aβ led to a decrease in anterograde trafficking of Golgi vesicles in dendrites of both resting and stimulated (with 50 mM KCl) neurons. We also characterized the ability of mirtazapine, a noradrenergic and specific serotonergic tetracyclic antidepressant (NaSSA), to rescue Golgi dynamics in dendrites. Mirtazapine treatment (10 μM) increased the number and both anterograde and retrograde motility, reducing the percentage of static Golgi vesicles. Finally, mirtazapine reverted the neurite atrophy induced by 24 h treatment with Aβ oligomers, suggesting that this drug is able to counteract the effects of Aβ by improving the dendritic trafficking of Golgi-related vesicles.
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Affiliation(s)
- Elsa Fabbretti
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | | | - Enrico Tongiorgi
- Department of Life Sciences, University of Trieste, Trieste, Italy
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Behrendt L, Hoischen C, Kaether C. Disease-causing mutated ATLASTIN 3 is excluded from distal axons and reduces axonal autophagy. Neurobiol Dis 2021; 155:105400. [PMID: 34019998 DOI: 10.1016/j.nbd.2021.105400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/27/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022] Open
Abstract
Mutations in the ER-network forming GTPase atlastin3 (ATL3) can cause axon degeneration of sensory neurons by not fully understood mechanisms. We here show that the hereditary sensory and autonomous neuropathy (HSAN)-causing ATL3 Y192C or P338R are excluded from distal axons by a barrier at the axon initial segment (AIS). This barrier is selective for mutated ATL3, but not wildtype ATL3 or unrelated ER-membrane proteins. Actin-depolymerization partially restores the transport of ATL3 Y192C into distal axons. The results point to the existence of a selective diffusion barrier in the ER membrane at the AIS, analogous to the AIS-based barriers for plasma membrane and cytosolic proteins. Functionally, the absence of ATL3 at the distal axon reduces axonal autophagy and the ER network deformation in the soma causes a reduction in axonal lysosomes. Both could contribute to axonal degeneration and eventually to HSAN.
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Affiliation(s)
- Laura Behrendt
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany
| | - Christian Hoischen
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany
| | - Christoph Kaether
- Leibniz-Institut für Alternsforschung-Fritz-Lipmann-Institut, 07745 Jena, Germany.
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37
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Morphological Heterogeneity of the Endoplasmic Reticulum within Neurons and Its Implications in Neurodegeneration. Cells 2021; 10:cells10050970. [PMID: 33919188 PMCID: PMC8143122 DOI: 10.3390/cells10050970] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a multipurpose organelle comprising dynamic structural subdomains, such as ER sheets and tubules, serving to maintain protein, calcium, and lipid homeostasis. In neurons, the single ER is compartmentalized with a careful segregation of the structural subdomains in somatic and neurite (axodendritic) regions. The distribution and arrangement of these ER subdomains varies between different neuronal types. Mutations in ER membrane shaping proteins and morphological changes in the ER are associated with various neurodegenerative diseases implying significance of ER morphology in maintaining neuronal integrity. Specific neurons, such as the highly arborized dopaminergic neurons, are prone to stress and neurodegeneration. Differences in morphology and functionality of ER between the neurons may account for their varied sensitivity to stress and neurodegenerative changes. In this review, we explore the neuronal ER and discuss its distinct morphological attributes and specific functions. We hypothesize that morphological heterogeneity of the ER in neurons is an important factor that accounts for their selective susceptibility to neurodegeneration.
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38
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Tang BL. Defects in early secretory pathway transport machinery components and neurodevelopmental disorders. Rev Neurosci 2021; 32:851-869. [PMID: 33781010 DOI: 10.1515/revneuro-2021-0020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/12/2021] [Indexed: 12/23/2022]
Abstract
The early secretory pathway, provisionally comprising of vesicular traffic between the endoplasmic reticulum (ER) and the Golgi apparatus, occurs constitutively in mammalian cells. Critical for a constant supply of secretory and plasma membrane (PM) materials, the pathway is presumably essential for general cellular function and survival. Neurons exhibit a high intensity in membrane dynamics and protein/lipid trafficking, with differential and polarized trafficking towards the somatodendritic and axonal PM domains. Mutations in genes encoding early secretory pathway membrane trafficking machinery components are known to result in neurodevelopmental or neurological disorders with disease manifestation in early life. Here, such rare disorders associated with autosomal recessive mutations in coat proteins, membrane tethering complexes and membrane fusion machineries responsible for trafficking in the early secretory pathway are summarily discussed. These mutations affected genes encoding subunits of coat protein complex I and II, subunits of transport protein particle (TRAPP) complexes, members of the YIP1 domain family (YIPF) and a SNAP receptor (SNARE) family member. Why the ubiquitously present and constitutively acting early secretory pathway machinery components could specifically affect neurodevelopment is addressed, with the plausible underlying disease etiologies and neuropathological mechanisms resulting from these mutations explored.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore117597, Singapore
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39
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Wei Z, Xu X, Fang Y, Khater M, Naughton SX, Hu G, Terry AV, Wu G. Rab43 GTPase directs postsynaptic trafficking and neuron-specific sorting of G protein-coupled receptors. J Biol Chem 2021; 296:100517. [PMID: 33676895 PMCID: PMC8050390 DOI: 10.1016/j.jbc.2021.100517] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 12/31/2022] Open
Abstract
G protein–coupled receptors (GPCRs) are important modulators of synaptic functions. A fundamental but poorly addressed question in neurobiology is how targeted GPCR trafficking is achieved. Rab GTPases are the master regulators of vesicle-mediated membrane trafficking, but their functions in the synaptic presentation of newly synthesized GPCRs are virtually unknown. Here, we investigate the role of Rab43, via dominant-negative inhibition and CRISPR–Cas9–mediated KO, in the export trafficking of α2-adrenergic receptor (α2-AR) and muscarinic acetylcholine receptor (mAChR) in primary neurons and cells. We demonstrate that Rab43 differentially regulates the overall surface expression of endogenous α2-AR and mAChR, as well as their signaling, in primary neurons. In parallel, Rab43 exerts distinct effects on the dendritic and postsynaptic transport of specific α2B-AR and M3 mAChR subtypes. More interestingly, the selective actions of Rab43 toward α2B-AR and M3 mAChR are neuronal cell specific and dictated by direct interaction. These data reveal novel, neuron-specific functions for Rab43 in the dendritic and postsynaptic targeting and sorting of GPCRs and imply multiple forward delivery routes for different GPCRs in neurons. Overall, this study provides important insights into regulatory mechanisms of GPCR anterograde traffic to the functional destination in neurons.
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Affiliation(s)
- Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yinquan Fang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA; Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Gang Hu
- Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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40
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Abstract
Neurons develop dendritic morphologies that bear cell type-specific features in dendritic field size and geometry, branch placement and density, and the types and distributions of synaptic contacts. Dendritic patterns influence the types and numbers of inputs a neuron receives, and the ways in which neural information is processed and transmitted in the circuitry. Even subtle alterations in dendritic structures can have profound consequences on neuronal function and are implicated in neurodevelopmental disorders. In this chapter, I review how growing dendrites acquire their exquisite patterns by drawing examples from diverse neuronal cell types in vertebrate and invertebrate model systems. Dendrite morphogenesis is shaped by intrinsic and extrinsic factors such as transcriptional regulators, guidance and adhesion molecules, neighboring cells and synaptic partners. I discuss molecular mechanisms that regulate dendrite morphogenesis with a focus on five aspects of dendrite patterning: (1) Dendritic cytoskeleton and cellular machineries that build the arbor; (2) Gene regulatory mechanisms; (3) Afferent cues that regulate dendritic arbor growth; (4) Space-filling strategies that optimize dendritic coverage; and (5) Molecular cues that specify dendrite wiring. Cell type-specific implementation of these patterning mechanisms produces the diversity of dendrite morphologies that wire the nervous system.
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41
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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42
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Reddish FN, Miller CL, Deng X, Dong B, Patel AA, Ghane MA, Mosca B, McBean C, Wu S, Solntsev KM, Zhuo Y, Gadda G, Fang N, Cox DN, Mabb AM, Treves S, Zorzato F, Yang JJ. Rapid subcellular calcium responses and dynamics by calcium sensor G-CatchER . iScience 2021; 24:102129. [PMID: 33665552 PMCID: PMC7900224 DOI: 10.1016/j.isci.2021.102129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 12/14/2020] [Accepted: 01/26/2021] [Indexed: 12/15/2022] Open
Abstract
The precise spatiotemporal characteristics of subcellular calcium (Ca2+) transients are critical for the physiological processes. Here we report a green Ca2+ sensor called "G-CatchER+" using a protein design to report rapid local ER Ca2+ dynamics with significantly improved folding properties. G-CatchER+ exhibits a superior Ca2+ on rate to G-CEPIA1er and has a Ca2+-induced fluorescence lifetimes increase. G-CatchER+ also reports agonist/antagonist triggered Ca2+ dynamics in several cell types including primary neurons that are orchestrated by IP3Rs, RyRs, and SERCAs with an ability to differentiate expression. Upon localization to the lumen of the RyR channel (G-CatchER+-JP45), we report a rapid local Ca2+ release that is likely due to calsequestrin. Transgenic expression of G-CatchER+ in Drosophila muscle demonstrates its utility as an in vivo reporter of stimulus-evoked SR local Ca2+ dynamics. G-CatchER+ will be an invaluable tool to examine local ER/SR Ca2+ dynamics and facilitate drug development associated with ER dysfunction.
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Affiliation(s)
- Florence N Reddish
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Cassandra L Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Xiaonan Deng
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Bin Dong
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Atit A Patel
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Mohammad A Ghane
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Barbara Mosca
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy
| | - Cheyenne McBean
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Shengnan Wu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, USA
| | - Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - You Zhuo
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Giovanni Gadda
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Ning Fang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Susan Treves
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy.,Department of Biomedicine, Basel University, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Francesco Zorzato
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy.,Department of Biomedicine, Basel University, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Jenny J Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
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43
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TSUBOI M, HIRABAYASHI Y. New insights into the regulation of synaptic transmission and plasticity by the endoplasmic reticulum and its membrane contacts. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:559-572. [PMID: 34897182 PMCID: PMC8687855 DOI: 10.2183/pjab.97.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Abstract
Mammalian neurons are highly compartmentalized yet very large cells. To provide each compartment with its distinct properties, metabolic homeostasis and molecular composition need to be precisely coordinated in a compartment-specific manner. Despite the importance of the endoplasmic reticulum (ER) as a platform for various biochemical reactions, such as protein synthesis, protein trafficking, and intracellular calcium control, the contribution of the ER to neuronal compartment-specific functions and plasticity remains elusive. Recent advances in the development of live imaging and serial scanning electron microscopy (sSEM) analysis have revealed that the neuronal ER is a highly dynamic organelle with compartment-specific structures. sSEM studies also revealed that the ER forms contacts with other membranes, such as the mitochondria and plasma membrane, although little is known about the functions of these ER-membrane contacts. In this review, we discuss the mechanisms and physiological roles of the ER structure and ER-mitochondria contacts in synaptic transmission and plasticity, thereby highlighting a potential link between organelle ultrastructure and neuronal functions.
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Affiliation(s)
- Masafumi TSUBOI
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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44
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Wang J, Fourriere L, Gleeson PA. Local Secretory Trafficking Pathways in Neurons and the Role of Dendritic Golgi Outposts in Different Cell Models. Front Mol Neurosci 2020; 13:597391. [PMID: 33324160 PMCID: PMC7726432 DOI: 10.3389/fnmol.2020.597391] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022] Open
Abstract
A fundamental characteristic of neurons is the relationship between the architecture of the polarized neuron and synaptic transmission between neurons. Intracellular membrane trafficking is paramount to establish and maintain neuronal structure; perturbation in trafficking results in defects in neurodevelopment and neurological disorders. Given the physical distance from the cell body to the distal sites of the axon and dendrites, transport of newly synthesized membrane proteins from the central cell body to their functional destination at remote, distal sites represents a conundrum. With the identification of secretory organelles in dendrites, including endoplasmic reticulum (ER) and Golgi outposts (GOs), recent studies have proposed local protein synthesis and trafficking distinct from the conventional anterograde transport pathways of the cell body. A variety of different model organisms, including Drosophila, zebrafish, and rodents, have been used to probe the organization and function of the local neuronal secretory network. Here, we review the evidence for local secretory trafficking pathways in dendrites in a variety of cell-based neuronal systems and discuss both the similarities and differences in the organization and role of the local secretory organelles, especially the GOs. In addition, we identify the gaps in the current knowledge and the potential advances using human induced pluripotent stem cells (iPSCs) in defining local membrane protein trafficking in human neurons and in understanding the molecular basis of neurological diseases.
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Affiliation(s)
- Jingqi Wang
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Lou Fourriere
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Paul A Gleeson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
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45
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Sugiyama S, Sugi J, Iijima T, Hou X. Single-Cell Visualization Deep in Brain Structures by Gene Transfer. Front Neural Circuits 2020; 14:586043. [PMID: 33328900 PMCID: PMC7710941 DOI: 10.3389/fncir.2020.586043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/29/2020] [Indexed: 11/13/2022] Open
Abstract
A projection neuron targets multiple regions beyond the functional brain area. In order to map neuronal connectivity in a massive neural network, a means for visualizing the entire morphology of a single neuron is needed. Progress has facilitated single-neuron analysis in the cerebral cortex, but individual neurons in deep brain structures remain difficult to visualize. To this end, we developed an in vivo single-cell electroporation method for juvenile and adult brains that can be performed under a standard stereomicroscope. This technique involves rapid gene transfection and allows the visualization of dendritic and axonal morphologies of individual neurons located deep in brain structures. The transfection efficiency was enhanced by directly injecting the expression vector encoding green fluorescent protein instead of monitoring cell attachment to the electrode tip. We obtained similar transfection efficiencies in both young adult (≥P40) and juvenile mice (P21-30). By tracing the axons of thalamocortical neurons, we identified a specific subtype of neuron distinguished by its projection pattern. Additionally, transfected mOrange-tagged vesicle-associated membrane protein 2-a presynaptic protein-was strongly localized in terminal boutons of thalamocortical neurons. Thus, our in vivo single-cell gene transfer system offers rapid single-neuron analysis deep in brain. Our approach combines observation of neuronal morphology with functional analysis of genes of interest, which can be useful for monitoring changes in neuronal activity corresponding to specific behaviors in living animals.
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Affiliation(s)
- Sayaka Sugiyama
- Laboratory of Neuronal Development, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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46
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Palavalli A, Tizón-Escamilla N, Rupprecht JF, Lecuit T. Deterministic and Stochastic Rules of Branching Govern Dendrite Morphogenesis of Sensory Neurons. Curr Biol 2020; 31:459-472.e4. [PMID: 33212017 DOI: 10.1016/j.cub.2020.10.054] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/22/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
Dendrite morphology is necessary for the correct integration of inputs that neurons receive. The branching mechanisms allowing neurons to acquire their type-specific morphology remain unclear. Classically, axon and dendrite patterns were shown to be guided by molecules, providing deterministic cues. However, the extent to which deterministic and stochastic mechanisms, based upon purely statistical bias, contribute to the emergence of dendrite shape is largely unknown. We address this issue using the Drosophila class I vpda multi-dendritic neurons. Detailed quantitative analysis of vpda dendrite morphogenesis indicates that the primary branch grows very robustly in a fixed direction, though secondary branch numbers and lengths showed fluctuations characteristic of stochastic systems. Live-tracking dendrites and computational modeling revealed how neuron shape emerges from few local statistical parameters of branch dynamics. We report key opposing aspects of how tree architecture feedbacks on the local probability of branch shrinkage. Child branches promote stabilization of parent branches, although self-repulsion promotes shrinkage. Finally, we show that self-repulsion, mediated by the adhesion molecule Dscam1, indirectly patterns the growth of secondary branches by spatially restricting their direction of stable growth perpendicular to the primary branch. Thus, the stochastic nature of secondary branch dynamics and the existence of geometric feedback emphasize the importance of self-organization in neuronal dendrite morphogenesis.
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Affiliation(s)
- Amrutha Palavalli
- Aix Marseille Université and CNRS, IBDM - UMR7288 and Turing Centre for Living Systems Campus de Luminy Case 907, Marseille 13288, France
| | - Nicolás Tizón-Escamilla
- Aix-Marseille Université, Université de Toulon, CNRS, CPT, Turing Centre for Living Systems Campus de Luminy Case 907, Marseille 13288, France
| | - Jean-François Rupprecht
- Aix-Marseille Université, Université de Toulon, CNRS, CPT, Turing Centre for Living Systems Campus de Luminy Case 907, Marseille 13288, France.
| | - Thomas Lecuit
- Aix Marseille Université and CNRS, IBDM - UMR7288 and Turing Centre for Living Systems Campus de Luminy Case 907, Marseille 13288, France; Collège de France, 11 Place Marcelin Berthelot, Paris 75005, France.
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47
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Lottes EN, Cox DN. Homeostatic Roles of the Proteostasis Network in Dendrites. Front Cell Neurosci 2020; 14:264. [PMID: 33013325 PMCID: PMC7461941 DOI: 10.3389/fncel.2020.00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular protein homeostasis, or proteostasis, is indispensable to the survival and function of all cells. Distinct from other cell types, neurons are long-lived, exhibiting architecturally complex and diverse multipolar projection morphologies that can span great distances. These properties present unique demands on proteostatic machinery to dynamically regulate the neuronal proteome in both space and time. Proteostasis is regulated by a distributed network of cellular processes, the proteostasis network (PN), which ensures precise control of protein synthesis, native conformational folding and maintenance, and protein turnover and degradation, collectively safeguarding proteome integrity both under homeostatic conditions and in the contexts of cellular stress, aging, and disease. Dendrites are equipped with distributed cellular machinery for protein synthesis and turnover, including dendritically trafficked ribosomes, chaperones, and autophagosomes. The PN can be subdivided into an adaptive network of three major functional pathways that synergistically govern protein quality control through the action of (1) protein synthesis machinery; (2) maintenance mechanisms including molecular chaperones involved in protein folding; and (3) degradative pathways (e.g., Ubiquitin-Proteasome System (UPS), endolysosomal pathway, and autophagy. Perturbations in any of the three arms of proteostasis can have dramatic effects on neurons, especially on their dendrites, which require tightly controlled homeostasis for proper development and maintenance. Moreover, the critical importance of the PN as a cell surveillance system against protein dyshomeostasis has been highlighted by extensive work demonstrating that the aggregation and/or failure to clear aggregated proteins figures centrally in many neurological disorders. While these studies demonstrate the relevance of derangements in proteostasis to human neurological disease, here we mainly review recent literature on homeostatic developmental roles the PN machinery plays in the establishment, maintenance, and plasticity of stable and dynamic dendritic arbors. Beyond basic housekeeping functions, we consider roles of PN machinery in protein quality control mechanisms linked to dendritic plasticity (e.g., dendritic spine remodeling during LTP); cell-type specificity; dendritic morphogenesis; and dendritic pruning.
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Affiliation(s)
- Erin N Lottes
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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48
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Signal Peptide Peptidase-Type Proteases: Versatile Regulators with Functions Ranging from Limited Proteolysis to Protein Degradation. J Mol Biol 2020; 432:5063-5078. [DOI: 10.1016/j.jmb.2020.05.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/02/2020] [Accepted: 05/19/2020] [Indexed: 12/15/2022]
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49
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Bocai NI, Marcora MS, Belfiori-Carrasco LF, Morelli L, Castaño EM. Endoplasmic Reticulum Stress in Tauopathies: Contrasting Human Brain Pathology with Cellular and Animal Models. J Alzheimers Dis 2020; 68:439-458. [PMID: 30775999 DOI: 10.3233/jad-181021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The accumulation and spreading of protein tau in the human brain are major features of neurodegenerative disorders known as tauopathies. In addition to several subcellular abnormalities, tau aggregation within neurons seems capable of triggering endoplasmic reticulum (ER) stress and the consequent unfolded protein response (UPR). In metazoans, full activation of a complex ER-UPR network may restore proteostasis and ER function or, if stress cannot be solved, commit cells to apoptosis. Due to these alternative outcomes (survival or death), the pharmacological manipulation of ER-UPR has become the focus of potential therapies in many human diseases, including tauopathies. Here we update and analyze the experimental data from human brain, cellular, and animal models linking tau accumulation and ER-UPR. We further discuss mechanistic aspects and put the ER-UPR into perspective as a possible therapeutic target in this group of diseases.
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Affiliation(s)
- Nadia I Bocai
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - María S Marcora
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lautaro F Belfiori-Carrasco
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Laura Morelli
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Eduardo M Castaño
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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50
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Nicholson L, Gervasi N, Falières T, Leroy A, Miremont D, Zala D, Hanus C. Whole-Cell Photobleaching Reveals Time-Dependent Compartmentalization of Soluble Proteins by the Axon Initial Segment. Front Cell Neurosci 2020; 14:180. [PMID: 32754013 PMCID: PMC7366827 DOI: 10.3389/fncel.2020.00180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/27/2020] [Indexed: 01/12/2023] Open
Abstract
By limiting protein exchange between the soma and the axon, the axon initial segment (AIS) enables the segregation of specific proteins and hence the differentiation of the somatodendritic compartment and the axonal compartment. Electron microscopy and super-resolution fluorescence imaging have provided important insights in the ultrastructure of the AIS. Yet, the full extent of its filtering properties is not fully delineated. In particular, it is unclear whether and how the AIS opposes the free exchange of soluble proteins. Here we describe a robust framework to combine whole-cell photobleaching and retrospective high-resolution imaging in developing neurons. With this assay, we found that cytoplasmic soluble proteins that are not excluded from the axon upon expression over tens of hours exhibit a strong mobility reduction at the AIS – i.e., are indeed compartmentalized – when monitored over tens of minutes. This form of compartmentalization is developmentally regulated, requires intact F-actin and may be correlated with the composition and ultrastructure of the submembranous spectrin cytoskeleton. Using computational modeling, we provide evidence that both neuronal morphology and the AIS regulate this compartmentalization but act on distinct time scales, with the AIS having a more pronounced effect on fast exchanges. Our results thus suggest that the rate of protein accumulation in the soma may impact to what extent and over which timescales freely moving molecules can be segregated from the axon. This in turn has important implications for our understanding of compartment-specific signaling in neurons.
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Affiliation(s)
- LaShae Nicholson
- Department of Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Nicolas Gervasi
- Center for Interdisciplinary Research in Biology, College de France, Inserm U1050, CNRS UMR 7241, Labex Memolife, Paris, France
| | - Thibault Falières
- Institute for Psychiatry and Neurosciences of Paris, Inserm UMR 1266, University of Paris, 4 GHU PARIS Psychiatrie & Neurosciences, Paris, France
| | - Adrien Leroy
- Center for Interdisciplinary Research in Biology, College de France, Inserm U1050, CNRS UMR 7241, Labex Memolife, Paris, France
| | - Dorian Miremont
- Institute for Psychiatry and Neurosciences of Paris, Inserm UMR 1266, University of Paris, 4 GHU PARIS Psychiatrie & Neurosciences, Paris, France
| | - Diana Zala
- Institute for Psychiatry and Neurosciences of Paris, Inserm UMR 1266, University of Paris, 4 GHU PARIS Psychiatrie & Neurosciences, Paris, France
| | - Cyril Hanus
- Institute for Psychiatry and Neurosciences of Paris, Inserm UMR 1266, University of Paris, 4 GHU PARIS Psychiatrie & Neurosciences, Paris, France
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