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Maejima I, Sato K. New aspects of a small GTPase RAB35 in brain development and function. Neural Regen Res 2025; 20:1971-1980. [PMID: 39254551 DOI: 10.4103/nrr.nrr-d-23-01543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 12/30/2023] [Indexed: 09/11/2024] Open
Abstract
In eukaryotic cells, organelles in the secretory, lysosomal, and endocytic pathways actively exchange biological materials with each other through intracellular membrane trafficking, which is the process of transporting the cargo of proteins, lipids, and other molecules to appropriate compartments via transport vesicles or intermediates. These processes are strictly regulated by various small GTPases such as the RAS-like in rat brain (RAB) protein family, which is the largest subfamily of the RAS superfamily. Dysfunction of membrane trafficking affects tissue homeostasis and leads to a wide range of diseases, including neurological disorders and neurodegenerative diseases. Therefore, it is important to understand the physiological and pathological roles of RAB proteins in brain function. RAB35, a member of the RAB family, is an evolutionarily conserved protein in metazoans. A wide range of studies using cultured mammalian cells and model organisms have revealed that RAB35 mediates various processes such as cytokinesis, endocytic recycling, actin bundling, and cell migration. RAB35 is also involved in neurite outgrowth and turnover of synaptic vesicles. We generated brain-specific Rab35 knockout mice to study the physiological roles of RAB35 in brain development and function. These mice exhibited defects in anxiety-related behaviors and spatial memory. Strikingly, RAB35 is required for the precise positioning of pyramidal neurons during hippocampal development, and thereby for normal hippocampal lamination. In contrast, layer formation in the cerebral cortex occurred superficially, even in the absence of RAB35, suggesting a predominant role for RAB35 in hippocampal development rather than in cerebral cortex development. Recent studies have suggested an association between RAB35 and neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. In this review, we provide an overview of the current understanding of subcellular functions of RAB35. We also provide insights into the physiological role of RAB35 in mammalian brain development and function, and discuss the involvement of RAB35 dysfunction in neurodegenerative diseases.
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Affiliation(s)
- Ikuko Maejima
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
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Tona R, Inagaki S, Ishibashi Y, Faridi R, Yousaf R, Roux I, Wilson E, Fenollar-Ferrer C, Chien WW, Belyantseva IA, Friedman TB. Interaction between the TBC1D24 TLDc domain and the KIBRA C2 domain is disrupted by two epilepsy-associated TBC1D24 missense variants. J Biol Chem 2024; 300:107725. [PMID: 39214300 DOI: 10.1016/j.jbc.2024.107725] [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: 03/27/2024] [Revised: 08/01/2024] [Accepted: 08/14/2024] [Indexed: 09/04/2024] Open
Abstract
Mutations of human TBC1D24 are associated with deafness, epilepsy, or DOORS syndrome (deafness, onychodystrophy, osteodystrophy, cognitive disability, and seizures). The causal relationships between TBC1D24 variants and the different clinical phenotypes are not understood. Our hypothesis is that phenotypic heterogeneity of missense mutations of TBC1D24 results, in part, from perturbed binding of different protein partners. To discover novel protein partners of TBC1D24, we conducted yeast two-hybrid (Y2H) screen using mouse full-length TBC1D24 as bait. Kidney and brain protein (KIBRA), a scaffold protein encoded by Wwc1, was identified as a partner of TBC1D24. KIBRA functions in the Hippo signaling pathway and is important for human cognition and memory. The TBC1D24 TLDc domain binds to KIBRA full-length and to its C2 domain, confirmed by Y2H assays. No interaction was detected with Y2H assays between the KIBRA C2 domain and TLDc domains of NCOA7, MEAK7, and OXR1. Moreover, the C2 domains of other WWC family proteins do not interact with the TLDc domain of TBC1D24, demonstrating specificity. The mRNAs encoding TBC1D24 and KIBRA proteins in mouse are coexpressed at least in a subset of hippocampal cells indicating availability to interact in vivo. As two epilepsy-associated recessive variants (Gly511Arg and Ala515Val) in the TLDc domain of human TBC1D24 disrupt the interaction with the human KIBRA C2 domain, this study reveals a pathogenic mechanism of TBC1D24-associated epilepsy, linking the TBC1D24 and KIBRA pathways. The interaction of TBC1D24-KIBRA is physiologically meaningful and necessary to reduce the risk of epilepsy.
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Affiliation(s)
- Risa Tona
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Sayaka Inagaki
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA.
| | - Yasuko Ishibashi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA; Inner Ear Gene Therapy Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Rizwan Yousaf
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Isabelle Roux
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA; Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Elizabeth Wilson
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Cristina Fenollar-Ferrer
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA; Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Wade W Chien
- Inner Ear Gene Therapy Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA; Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins School of Medicine, Maryland, USA
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Maryland, USA.
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McLean JW, VanHart M, McWilliams MP, Farmer CB, Crossman DK, Cowell RM, Wilson JA, Wilson SM. Analysis of the neuromuscular deficits caused by STAM1 deficiency. CURRENT RESEARCH IN NEUROBIOLOGY 2024; 7:100138. [PMID: 39280771 PMCID: PMC11401115 DOI: 10.1016/j.crneur.2024.100138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 07/17/2024] [Accepted: 08/20/2024] [Indexed: 09/18/2024] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) pathway is composed of a series of protein complexes that are essential for sorting cargo through the endosome. In neurons, the ESCRT pathway is a key mediator of many cellular pathways that regulate neuronal morphogenesis as well as synaptic growth and function. The ESCRT-0 complex, consisting of HGS (hepatocyte growth factor-regulated tyrosine kinase substrate) and STAM (signal-transducing adaptor molecule), acts as a gate keeper to this pathway, ultimately determining the fate of the endosomal cargo. We previously showed that a single nucleotide substitution in Hgs results in structural and functional changes in the nervous system of teetering mice. To determine if these changes occurred as a function of HGS's role in the ESCRT pathway and its association with STAM1, we investigated if STAM1 deficiency also leads to a similar impairment of the nervous system. In contrast to teetering mice that die within 5 weeks of age and exhibit reduced body mass, 1-month-old Stam1 knockout mice were not visibly different from controls. However, by 3 months of age, STAM1 deficiency caused reduced muscle mass, strength, and motor performance. These changes in motor function did not correlate with either a loss in motor neuron number or abnormal myelination of peripheral nerves. Instead, the motor endplate structure was altered in the Stam1 knockout mice by 1 month of age and continued to degenerate over time, correlating with a significant reduction in muscle fiber size and increased expression of the embryonic γ acetylcholine receptor (AChR) subunit at 3 months of age. There was also a significant reduction in the levels of two presynaptic SNARE proteins, VTI1A and VAMP2, in the motor neurons of the Stam1 knockout mice. As loss of STAM1 expression replicates many of the structural changes at the motor endplates that we have previously reported with loss of HGS, these results suggest that the HGS/STAM1 complex plays a critical role in maintaining synaptic structure and function in the mammalian nervous system.
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Affiliation(s)
- John W McLean
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Mary VanHart
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Madilyn P McWilliams
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Charlene B Farmer
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - David K Crossman
- Department of Human Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Rita M Cowell
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Julie A Wilson
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
| | - Scott M Wilson
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, 35294, Alabama, USA
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Asmerian H, Alberts J, Sanetra AM, Diaz AJ, Silm K. Role of adaptor protein complexes in generating functionally distinct synaptic vesicle pools. J Physiol 2024. [PMID: 39034608 DOI: 10.1113/jp286179] [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: 04/24/2024] [Accepted: 07/05/2024] [Indexed: 07/23/2024] Open
Abstract
The synaptic vesicle (SV) cycle ensures the release of neurotransmitters and the replenishment of SVs to sustain neuronal activity. Multiple endocytosis and sorting pathways contribute to the recapture of the SV membrane and proteins after fusion. Adaptor protein (AP) complexes are among the critical components of the SV retrieval machinery. The canonical clathrin adaptor AP2 ensures the replenishment of most SVs across many neuronal populations. An alternative AP1/AP3-dependent process mediates the formation of a subset of SVs that differ from AP2 vesicles in molecular composition and respond preferentially during higher frequency firing. Furthermore, recent studies show that vesicular transporters for different neurotransmitters depend to a different extent on the AP3 pathway and this affects the release properties of the respective neurotransmitters. This review focuses on the current understanding of the AP-dependent molecular and functional diversity among SVs. We also discuss the contribution of these pathways to the regulation of neurotransmitter release across neuronal populations.
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Affiliation(s)
- Hrach Asmerian
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jacob Alberts
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Anna M Sanetra
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alexia J Diaz
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Katlin Silm
- Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Dou D, Aiken J, Holzbaur EL. RAB3 phosphorylation by pathogenic LRRK2 impairs trafficking of synaptic vesicle precursors. J Cell Biol 2024; 223:e202307092. [PMID: 38512027 PMCID: PMC10959120 DOI: 10.1083/jcb.202307092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 02/01/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024] Open
Abstract
Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), characterized by debilitating motor and non-motor symptoms. Increased phosphorylation of a subset of RAB GTPases by LRRK2 is implicated in PD pathogenesis. We find that increased phosphorylation of RAB3A, a cardinal synaptic vesicle precursor (SVP) protein, disrupts anterograde axonal transport of SVPs in iPSC-derived human neurons (iNeurons) expressing hyperactive LRRK2-p.R1441H. Knockout of the opposing protein phosphatase 1H (PPM1H) in iNeurons phenocopies this effect. In these models, the compartmental distribution of synaptic proteins is altered; synaptophysin and synaptobrevin-2 become sequestered in the neuronal soma with decreased delivery to presynaptic sites along the axon. We find that RAB3A phosphorylation disrupts binding to the motor adaptor MADD, potentially preventing the formation of the RAB3A-MADD-KIF1A/1Bβ complex driving anterograde SVP transport. RAB3A hyperphosphorylation also disrupts interactions with RAB3GAP and RAB-GDI1. Our results reveal a mechanism by which pathogenic hyperactive LRRK2 may contribute to the altered synaptic homeostasis associated with characteristic non-motor and cognitive manifestations of PD.
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Affiliation(s)
- Dan Dou
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jayne Aiken
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erika L.F. Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Bertin F, Jara-Wilde J, Auer B, Köhler-Solís A, González-Silva C, Thomas U, Sierralta J. Drosophila Atlastin regulates synaptic vesicle mobilization independent of bone morphogenetic protein signaling. Biol Res 2023; 56:49. [PMID: 37710314 PMCID: PMC10503011 DOI: 10.1186/s40659-023-00462-1] [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: 06/08/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND The endoplasmic reticulum (ER) contacts endosomes in all parts of a motor neuron, including the axon and presynaptic terminal, to move structural proteins, proteins that send signals, and lipids over long distances. Atlastin (Atl), a large GTPase, is required for membrane fusion and the structural dynamics of the ER tubules. Atl mutations are the second most common cause of Hereditary Spastic Paraplegia (HSP), which causes spasticity in both sexes' lower extremities. Through an unknown mechanism, Atl mutations stimulate the BMP (bone morphogenetic protein) pathway in vertebrates and Drosophila. Synaptic defects are caused by atl mutations, which affect the abundance and distribution of synaptic vesicles (SV) in the bouton. We hypothesize that BMP signaling, does not cause Atl-dependent SV abnormalities in Drosophila. RESULTS We show that atl knockdown in motor neurons (Atl-KD) increases synaptic and satellite boutons in the same way that constitutively activating the BMP-receptor Tkv (thick veins) (Tkv-CA) increases the bouton number. The SV proteins Cysteine string protein (CSP) and glutamate vesicular transporter are reduced in Atl-KD and Tkv-CA larvae. Reducing the activity of the BMP receptor Wishful thinking (wit) can rescue both phenotypes. Unlike Tkv-CA larvae, Atl-KD larvae display altered activity-dependent distributions of CSP staining. Furthermore, Atl-KD larvae display an increased FM 1-43 unload than Control and Tkv-CA larvae. As decreasing wit function does not reduce the phenotype, our hypothesis that BMP signaling is not involved is supported. We also found that Rab11/CSP colocalization increased in Atl-KD larvae, which supports the concept that late recycling endosomes regulate SV movements. CONCLUSIONS Our findings reveal that Atl modulates neurotransmitter release in motor neurons via SV distribution independently of BMP signaling, which could explain the observed SV accumulation and synaptic dysfunction. Our data suggest that Atl is involved in membrane traffic as well as formation and/or recycling of the late endosome.
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Affiliation(s)
- Francisca Bertin
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Jorge Jara-Wilde
- SCIAN-Lab, Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Computational Sciences, Faculty of Physical and Mathematical Sciences, Universidad de Chile, Santiago, Chile
| | - Benedikt Auer
- Laboratory of Neuronal and Synaptic Signals, Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Andrés Köhler-Solís
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Carolina González-Silva
- Biomedical Neuroscience Institute (BNI), Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Ulrich Thomas
- Functional Genetics of the Synapse, Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
| | - Jimena Sierralta
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.
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Dou D, Aiken J, Holzbaur EL. RAB3 phosphorylation by pathogenic LRRK2 impairs trafficking of synaptic vesicle precursors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550521. [PMID: 37546777 PMCID: PMC10402060 DOI: 10.1101/2023.07.25.550521] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), characterized by debilitating motor and non-motor symptoms. Increased phosphorylation of a subset of RAB GTPases by LRRK2 is implicated in PD pathogenesis. We find that increased phosphorylation of RAB3A, a cardinal synaptic vesicle precursor (SVP) protein, disrupts anterograde axonal transport of SVPs in iPSC-derived human neurons (iNeurons) expressing hyperactive LRRK2-p.R1441H. Knockout of the opposing protein phosphatase 1H (PPM1H) in iNeurons phenocopies this effect. In these models, the compartmental distribution of synaptic proteins is altered; synaptophysin and synaptobrevin-2 become sequestered in the neuronal soma with decreased delivery to presynaptic sites along the axon. We find that RAB3A phosphorylation disrupts binding to the motor adapter MADD, potentially preventing formation of the RAB3A-MADD-KIF1A/1Bβ complex driving anterograde SVP transport. RAB3A hyperphosphorylation also disrupts interactions with RAB3GAP and RAB-GDI1. Our results reveal a mechanism by which pathogenic hyperactive LRRK2 may contribute to the altered synaptic homeostasis associated with characteristic non-motor and cognitive manifestations of PD.
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Affiliation(s)
- Dan Dou
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jayne Aiken
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erika L.F. Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Maejima I, Hara T, Tsukamoto S, Koizumi H, Kawauchi T, Akuzawa T, Hirai R, Kobayashi H, Isobe I, Emoto K, Kosako H, Sato K. RAB35 is required for murine hippocampal development and functions by regulating neuronal cell distribution. Commun Biol 2023; 6:440. [PMID: 37085665 PMCID: PMC10121692 DOI: 10.1038/s42003-023-04826-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 04/07/2023] [Indexed: 04/23/2023] Open
Abstract
RAB35 is a multifunctional small GTPase that regulates endocytic recycling, cytoskeletal rearrangement, and cytokinesis. However, its physiological functions in mammalian development remain unclear. Here, we generated Rab35-knockout mice and found that RAB35 is essential for early embryogenesis. Interestingly, brain-specific Rab35-knockout mice displayed severe defects in hippocampal lamination owing to impaired distribution of pyramidal neurons, although defects in cerebral cortex formation were not evident. In addition, Rab35-knockout mice exhibited defects in spatial memory and anxiety-related behaviors. Quantitative proteomics indicated that the loss of RAB35 significantly affected the levels of other RAB proteins associated with endocytic trafficking, as well as some neural cell adhesion molecules, such as contactin-2. Collectively, our findings revealed that RAB35 is required for precise neuronal distribution in the developing hippocampus by regulating the expression of cell adhesion molecules, thereby influencing spatial memory.
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Affiliation(s)
- Ikuko Maejima
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan
| | - Taichi Hara
- Laboratory of Food and Life Science, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, 359-1192, Japan
| | - Satoshi Tsukamoto
- Laboratory Animal and Genome Sciences Section, National Institutes for Quantum and Radiological Science and Technology, Chiba, Chiba, 263-8555, Japan
| | - Hiroyuki Koizumi
- Department of Biological Sciences, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Molecular and Cellular Biology, School of Pharmaceutical Sciences, Ohu University, Koriyama, Fukushima, 963-8611, Japan
| | - Takeshi Kawauchi
- Department of Adaptive and Maladaptive Responses in Health and Diseases, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Tomoko Akuzawa
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan
| | - Rika Hirai
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan
| | - Hisae Kobayashi
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan
| | - Inoya Isobe
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan
| | - Kazuo Emoto
- Department of Biological Sciences, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hidetaka Kosako
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Tokushima, 770-8503, Japan
| | - Ken Sato
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan.
- Gunma University Initiative for Advanced Research (GIAR), Gunma University, Maebashi, Gunma, 371-8512, Japan.
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Zhou X, Gan G, Sun Y, Ou M, Geng J, Wang J, Yang X, Huang S, Jia D, Xie W, He H. GTPase-activating protein TBC1D5 coordinates with retromer to constrain synaptic growth by inhibiting BMP signaling. J Genet Genomics 2023; 50:163-177. [PMID: 36473687 DOI: 10.1016/j.jgg.2022.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022]
Abstract
Formation and plasticity of neural circuits rely on precise regulation of synaptic growth. At Drosophila neuromuscular junction (NMJ), Bone Morphogenetic Protein (BMP) signaling is critical for many aspects of synapse formation and function. The evolutionarily conserved retromer complex and its associated GTPase-activating protein TBC1D5 are critical regulators of membrane trafficking and cellular signaling. However, their functions in regulating the formation of NMJ are less understood. Here, we report that TBC1D5 is required for inhibition of synaptic growth, and loss of TBC1D5 leads to abnormal presynaptic terminal development, including excessive satellite boutons and branch formation. Ultrastructure analysis reveals that the size of synaptic vesicles and the density of subsynaptic reticulum are increased in TBC1D5 mutant boutons. Disruption of interactions of TBC1D5 with Rab7 and retromer phenocopies the loss of TBC1D5. Unexpectedly, we find that TBC1D5 is functionally linked to Rab6, in addition to Rab7, to regulate synaptic growth. Mechanistically, we show that loss of TBC1D5 leads to upregulated BMP signaling by increasing the protein level of BMP type II receptor Wishful Thinking (Wit) at NMJ. Overall, our data establish that TBC1D5 in coordination with retromer constrains synaptic growth by regulating Rab7 activity, which negatively regulates BMP signaling through inhibiting Wit level.
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Affiliation(s)
- Xiu Zhou
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Guangming Gan
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China; The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China
| | - Yichen Sun
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Mengzhu Ou
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Junhua Geng
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China
| | - Jing Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xi Yang
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shu Huang
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, Sichuan 610041, China
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease (MOE), School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China.
| | - Haihuai He
- State Key Laboratory of Biotherapy, Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
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10
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Michetti C, Falace A, Benfenati F, Fassio A. Synaptic genes and neurodevelopmental disorders: From molecular mechanisms to developmental strategies of behavioral testing. Neurobiol Dis 2022; 173:105856. [PMID: 36070836 DOI: 10.1016/j.nbd.2022.105856] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022] Open
Abstract
Synaptopathies are a class of neurodevelopmental disorders caused by modification in genes coding for synaptic proteins. These proteins oversee the process of neurotransmission, mainly controlling the fusion and recycling of synaptic vesicles at the presynaptic terminal, the expression and localization of receptors at the postsynapse and the coupling between the pre- and the postsynaptic compartments. Murine models, with homozygous or heterozygous deletion for several synaptic genes or knock-in for specific pathogenic mutations, have been developed. They have proved to be extremely informative for understanding synaptic physiology, as well as for clarifying the patho-mechanisms leading to developmental delay, epilepsy and motor, cognitive and social impairments that are the most common clinical manifestations of neurodevelopmental disorders. However, the onset of these disorders emerges during infancy and adolescence while the behavioral phenotyping is often conducted in adult mice, missing important information about the impact of synaptic development and maturation on the manifestation of the behavioral phenotype. Here, we review the main achievements obtained by behavioral testing in murine models of synaptopathies and propose a battery of behavioral tests to improve classification, diagnosis and efficacy of potential therapeutic treatments. Our aim is to underlie the importance of studying behavioral development and better focusing on disease onset and phenotypes.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy.
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
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11
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Birdsall V, Kirwan K, Zhu M, Imoto Y, Wilson SM, Watanabe S, Waites CL. Axonal transport of Hrs is activity dependent and facilitates synaptic vesicle protein degradation. Life Sci Alliance 2022; 5:5/10/e202000745. [PMID: 35636965 PMCID: PMC9152131 DOI: 10.26508/lsa.202000745] [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: 04/19/2020] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 11/29/2022] Open
Abstract
This study describes an activity-dependent mechanism for transporting ESCRT-0 protein Hrs to synaptic vesicle (SV) pools, facilitating SV protein degradation in response to increased neuronal firing. Turnover of synaptic vesicle (SV) proteins is vital for the maintenance of healthy and functional synapses. SV protein turnover is driven by neuronal activity in an endosomal sorting complex required for transport (ESCRT)-dependent manner. Here, we characterize a critical step in this process: axonal transport of ESCRT-0 component Hrs, necessary for sorting proteins into the ESCRT pathway and recruiting downstream ESCRT machinery to catalyze multivesicular body (MVB) formation. We find that neuronal activity stimulates the formation of presynaptic endosomes and MVBs, as well as the motility of Hrs+ vesicles in axons and their delivery to SV pools. Hrs+ vesicles co-transport ESCRT-0 component STAM1 and comprise a subset of Rab5+ vesicles, likely representing pro-degradative early endosomes. Furthermore, we identify kinesin motor protein KIF13A as essential for the activity-dependent transport of Hrs to SV pools and the degradation of SV membrane proteins. Together, these data demonstrate a novel activity- and KIF13A-dependent mechanism for mobilizing axonal transport of ESCRT machinery to facilitate the degradation of SV membrane proteins.
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Affiliation(s)
- Veronica Birdsall
- Neurobiology and Behavior PhD Program, Columbia University, New York, NY, USA
| | - Konner Kirwan
- Neurobiology and Behavior PhD Program, Columbia University, New York, NY, USA
| | - Mei Zhu
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Yuuta Imoto
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Scott M Wilson
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD, USA.,Solomon H Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Clarissa L Waites
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA .,Department of Neuroscience, Columbia University, New York, NY, USA
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12
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Kuijpers M. Keeping synapses in shape: degradation pathways in the healthy and aging brain. Neuronal Signal 2022; 6:NS20210063. [PMID: 35813265 PMCID: PMC9208270 DOI: 10.1042/ns20210063] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
Synapses maintain their molecular composition, plasticity and function through the concerted action of protein synthesis and removal. The complex and polarized neuronal architecture poses specific challenges to the logistics of protein and organelle turnover since protein synthesis and degradation mainly happen in the cell soma. In addition, post-mitotic neurons accumulate damage over a lifetime, challenging neuronal degradative pathways and making them particularly susceptible to the effects of aging. This review will summarize the current knowledge on neuronal protein turnover mechanisms with a particular focus on the presynapse, including the proteasome, autophagy and the endolysosomal route and their roles in regulating presynaptic proteostasis and function. In addition, the author will discuss how physiological brain aging, which entails a progressive decline in cognitive functions, affects synapses and the degradative machinery.
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Affiliation(s)
- Marijn Kuijpers
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, The Netherlands
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13
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Liu GT, Kochlamazashvili G, Puchkov D, Müller R, Schultz C, Mackintosh AI, Vollweiter D, Haucke V, Soykan T. Endosomal phosphatidylinositol 3-phosphate controls synaptic vesicle cycling and neurotransmission. EMBO J 2022; 41:e109352. [PMID: 35318705 PMCID: PMC9058544 DOI: 10.15252/embj.2021109352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 02/24/2022] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
Neural circuit function requires mechanisms for controlling neurotransmitter release and the activity of neuronal networks, including modulation by synaptic contacts, synaptic plasticity, and homeostatic scaling. However, how neurons intrinsically monitor and feedback control presynaptic neurotransmitter release and synaptic vesicle (SV) recycling to restrict neuronal network activity remains poorly understood at the molecular level. Here, we investigated the reciprocal interplay between neuronal endosomes, organelles of central importance for the function of synapses, and synaptic activity. We show that elevated neuronal activity represses the synthesis of endosomal lipid phosphatidylinositol 3-phosphate [PI(3)P] by the lipid kinase VPS34. Neuronal activity in turn is regulated by endosomal PI(3)P, the depletion of which reduces neurotransmission as a consequence of perturbed SV endocytosis. We find that this mechanism involves Calpain 2-mediated hyperactivation of Cdk5 downstream of receptor- and activity-dependent calcium influx. Our results unravel an unexpected function for PI(3)P-containing neuronal endosomes in the control of presynaptic vesicle cycling and neurotransmission, which may explain the involvement of the PI(3)P-producing VPS34 kinase in neurological disease and neurodegeneration.
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Affiliation(s)
- Guan-Ting Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | | | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Rainer Müller
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Carsten Schultz
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Heidelberg, Germany.,Department of Chemical Physiology & Biochemistry, Oregon Health & Science University (OHSU), Portland, OR, USA
| | - Albert I Mackintosh
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Dennis Vollweiter
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Faculty of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Tolga Soykan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
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14
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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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15
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Ivanova D, Cousin MA. Synaptic Vesicle Recycling and the Endolysosomal System: A Reappraisal of Form and Function. Front Synaptic Neurosci 2022; 14:826098. [PMID: 35280702 PMCID: PMC8916035 DOI: 10.3389/fnsyn.2022.826098] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/03/2022] [Indexed: 12/15/2022] Open
Abstract
The endolysosomal system is present in all cell types. Within these cells, it performs a series of essential roles, such as trafficking and sorting of membrane cargo, intracellular signaling, control of metabolism and degradation. A specific compartment within central neurons, called the presynapse, mediates inter-neuronal communication via the fusion of neurotransmitter-containing synaptic vesicles (SVs). The localized recycling of SVs and their organization into functional pools is widely assumed to be a discrete mechanism, that only intersects with the endolysosomal system at specific points. However, evidence is emerging that molecules essential for endolysosomal function also have key roles within the SV life cycle, suggesting that they form a continuum rather than being isolated processes. In this review, we summarize the evidence for key endolysosomal molecules in SV recycling and propose an alternative model for membrane trafficking at the presynapse. This includes the hypotheses that endolysosomal intermediates represent specific functional SV pools, that sorting of cargo to SVs is mediated via the endolysosomal system and that manipulation of this process can result in both plastic changes to neurotransmitter release and pathophysiology via neurodegeneration.
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Affiliation(s)
- Daniela Ivanova
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Daniela Ivanova,
| | - Michael A. Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
- Michael A. Cousin,
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16
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Cho TS, Beigaitė E, Klein NE, Sweeney ST, Bhattacharya MRC. The Putative Drosophila TMEM184B Ortholog Tmep Ensures Proper Locomotion by Restraining Ectopic Firing at the Neuromuscular Junction. Mol Neurobiol 2022; 59:2605-2619. [PMID: 35107803 PMCID: PMC9018515 DOI: 10.1007/s12035-022-02760-3] [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: 09/13/2021] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
TMEM184B is a putative seven-pass membrane protein that promotes axon degeneration after injury. TMEM184B mutation causes aberrant neuromuscular architecture and sensory and motor behavioral defects in mice. The mechanism through which TMEM184B causes neuromuscular defects is unknown. We employed Drosophila melanogaster to investigate the function of the closely related gene, Tmep (CG12004), at the neuromuscular junction. We show that Tmep is required for full adult viability and efficient larval locomotion. Tmep mutant larvae have a reduced body contraction rate compared to controls, with stronger deficits in females. In recordings from body wall muscles, Tmep mutants show substantial hyperexcitability, with many postsynaptic potentials fired in response to a single stimulation, consistent with a role for Tmep in restraining synaptic excitability. Additional branches and satellite boutons at Tmep mutant neuromuscular junctions are consistent with an activity-dependent synaptic overgrowth. Tmep is expressed in endosomes and synaptic vesicles within motor neurons, suggesting a possible role in synaptic membrane trafficking. Using RNAi knockdown, we show that Tmep is required in motor neurons for proper larval locomotion and excitability, and that its reduction increases levels of presynaptic calcium. Locomotor defects can be rescued by presynaptic knockdown of endoplasmic reticulum calcium channels or by reducing evoked release probability, further suggesting that excess synaptic activity drives behavioral deficiencies. Our work establishes a critical function for Tmep in the regulation of synaptic transmission and locomotor behavior.
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Affiliation(s)
- Tiffany S Cho
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Eglė Beigaitė
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Nathaniel E Klein
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Sean T Sweeney
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Martha R C Bhattacharya
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA.
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17
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Zhang J, Jiang Z, Shi A. Rab GTPases: The principal players in crafting the regulatory landscape of endosomal trafficking. Comput Struct Biotechnol J 2022; 20:4464-4472. [PMID: 36051867 PMCID: PMC9418685 DOI: 10.1016/j.csbj.2022.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/05/2022] [Accepted: 08/07/2022] [Indexed: 11/16/2022] Open
Abstract
After endocytosis, diverse cargos are sorted into endosomes and directed to various destinations, including extracellular macromolecules, membrane lipids, and membrane proteins. Some cargos are returned to the plasma membrane via endocytic recycling. In contrast, others are delivered to the Golgi apparatus through the retrograde pathway, while the rest are transported to late endosomes and eventually to lysosomes for degradation. Rab GTPases are major regulators that ensure cargos are delivered to their proper destinations. Rabs are localized to distinct endosomes and play predominant roles in membrane budding, vesicle formation and motility, vesicle tethering, and vesicle fusion by recruiting effectors. The cascades between Rabs via shared effectors or the recruitment of Rab activators provide an additional layer of spatiotemporal regulation of endocytic trafficking. Notably, several recent studies have indicated that disorders of Rab-mediated endocytic transports are closely associated with diseases such as immunodeficiency, cancer, and neurological disorders.
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18
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Peng YJ, Geng J, Wu Y, Pinales C, Langen J, Chang YC, Buser C, Chang KT. Minibrain kinase and calcineurin coordinate activity-dependent bulk endocytosis through synaptojanin. J Cell Biol 2021; 220:212674. [PMID: 34596663 PMCID: PMC8491876 DOI: 10.1083/jcb.202011028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/28/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022] Open
Abstract
Neurons use multiple modes of endocytosis, including clathrin-mediated endocytosis (CME) and activity-dependent bulk endocytosis (ADBE), during mild and intense neuronal activity, respectively, to maintain stable neurotransmission. While molecular players modulating CME are well characterized, factors regulating ADBE and mechanisms coordinating CME and ADBE activations remain poorly understood. Here we report that Minibrain/DYRK1A (Mnb), a kinase mutated in autism and up-regulated in Down's syndrome, plays a novel role in suppressing ADBE. We demonstrate that Mnb, together with calcineurin, delicately coordinates CME and ADBE by controlling the phosphoinositol phosphatase activity of synaptojanin (Synj) during varying synaptic demands. Functional domain analyses reveal that Synj's 5'-phosphoinositol phosphatase activity suppresses ADBE, while SAC1 activity is required for efficient ADBE. Consequently, Parkinson's disease mutation in Synj's SAC1 domain impairs ADBE. These data identify Mnb and Synj as novel regulators of ADBE and further indicate that CME and ADBE are differentially governed by Synj's dual phosphatase domains.
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Affiliation(s)
- Yi-Jheng Peng
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA.,Neuroscience Graduate Program, University of Southern California, Los Angeles, CA
| | - Junhua Geng
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Ying Wu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | | | - Jennifer Langen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Yen-Ching Chang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | | | - Karen T Chang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA.,Neuroscience Graduate Program, University of Southern California, Los Angeles, CA.,Department of Physiology & Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA
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19
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Timpanaro T, La Mendola F, Billone S, Nora AD, Collotta A, Sauna A, Salafia S, Falsaperla R. TBC1D24 and Its Related Epileptic Encephalopathy. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1728645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
TBC1D24, mapped to 16p13.3, encodes a protein containing a Tre2/Bub2/Cdc16 (TBC) domain, belonging to the super-family of Rab GTPase activating proteins (Rab-GAP). These proteins regulate various functions, including the regulation of the traffic of the vesicular membrane. Several TBC1D24 mutations have been related to autosomal recessive neurological disorders, including severe developmental encephalopathies with malignant early childhood epilepsy, benign epilepsy, epileptic encephalopathy, and a complex neurological syndrome characterized by deafness, onychodystrophy, bone and neurological degeneration. Mutations of TBC1D24 have also been reported in patients with nonsyndromic deafness with dominant or recessive inheritance. Mechanisms underlying TBC1D24-associated disorders and the functions of TBC1D24 products in the generation of such complex spectrum of diseases remain partly unclear and future studies are needed to clarify this aspect, in order to improve the management of seizures and for the prevention of complication (including death) of newly diagnosed patients affected by TBC1D24-related disorders.
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Affiliation(s)
- Tiziana Timpanaro
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | | | - Sebastiano Billone
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Alessandra Di Nora
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Ausilia Collotta
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Alessandra Sauna
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | | | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
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20
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Koss DJ, Campesan S, Giorgini F, Outeiro TF. Dysfunction of RAB39B-Mediated Vesicular Trafficking in Lewy Body Diseases. Mov Disord 2021; 36:1744-1758. [PMID: 33939203 DOI: 10.1002/mds.28605] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/16/2022] Open
Abstract
Intracellular vesicular trafficking is essential for neuronal development, function, and homeostasis and serves to process, direct, and sort proteins, lipids, and other cargo throughout the cell. This intricate system of membrane trafficking between different compartments is tightly orchestrated by Ras analog in brain (RAB) GTPases and their effectors. Of the 66 members of the RAB family in humans, many have been implicated in neurodegenerative diseases and impairment of their functions contributes to cellular stress, protein aggregation, and death. Critically, RAB39B loss-of-function mutations are known to be associated with X-linked intellectual disability and with rare early-onset Parkinson's disease. Moreover, recent studies have highlighted altered RAB39B expression in idiopathic cases of several Lewy body diseases (LBDs). This review contextualizes the role of RAB proteins in LBDs and highlights the consequences of RAB39B impairment in terms of endosomal trafficking, neurite outgrowth, synaptic maturation, autophagy, as well as alpha-synuclein homeostasis. Additionally, the potential for therapeutic intervention is examined via a discussion of the recent progress towards the development of specific RAB modulators. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- David J Koss
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Susanna Campesan
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Tiago F Outeiro
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,Max Planck Institute for Experimental Medicine, Goettingen, Germany.,Scientific employee with a honorary contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany
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21
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Integrins protect sensory neurons in models of paclitaxel-induced peripheral sensory neuropathy. Proc Natl Acad Sci U S A 2021; 118:2006050118. [PMID: 33876743 DOI: 10.1073/pnas.2006050118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a major side effect from cancer treatment with no known method for prevention or cure in clinics. CIPN often affects unmyelinated nociceptive sensory terminals. Despite the high prevalence, molecular and cellular mechanisms that lead to CIPN are still poorly understood. Here, we used a genetically tractable Drosophila model and primary sensory neurons isolated from adult mouse to examine the mechanisms underlying CIPN and identify protective pathways. We found that chronic treatment of Drosophila larvae with paclitaxel caused degeneration and altered the branching pattern of nociceptive neurons, and reduced thermal nociceptive responses. We further found that nociceptive neuron-specific overexpression of integrins, which are known to support neuronal maintenance in several systems, conferred protection from paclitaxel-induced cellular and behavioral phenotypes. Live imaging and superresolution approaches provide evidence that paclitaxel treatment causes cellular changes that are consistent with alterations in endosome-mediated trafficking of integrins. Paclitaxel-induced changes in recycling endosomes precede morphological degeneration of nociceptive neuron arbors, which could be prevented by integrin overexpression. We used primary dorsal root ganglia (DRG) neuron cultures to test conservation of integrin-mediated protection. We show that transduction of a human integrin β-subunit 1 also prevented degeneration following paclitaxel treatment. Furthermore, endogenous levels of surface integrins were decreased in paclitaxel-treated mouse DRG neurons, suggesting that paclitaxel disrupts recycling in vertebrate sensory neurons. Altogether, our study supports conserved mechanisms of paclitaxel-induced perturbation of integrin trafficking and a therapeutic potential of restoring neuronal interactions with the extracellular environment to antagonize paclitaxel-induced toxicity in sensory neurons.
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22
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Ivanova D, Dobson KL, Gajbhiye A, Davenport EC, Hacker D, Ultanir SK, Trost M, Cousin MA. Control of synaptic vesicle release probability via VAMP4 targeting to endolysosomes. SCIENCE ADVANCES 2021; 7:7/18/eabf3873. [PMID: 33931449 PMCID: PMC8087399 DOI: 10.1126/sciadv.abf3873] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/11/2021] [Indexed: 05/03/2023]
Abstract
Synaptic vesicle (SV) release probability (Pr), determines the steady state and plastic control of neurotransmitter release. However, how diversity in SV composition arises and regulates the Pr of individual SVs is not understood. We found that modulation of the copy number of the noncanonical vesicular SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor), vesicle-associated membrane protein 4 (VAMP4), on SVs is key for regulating Pr. Mechanistically, this is underpinned by its reduced ability to form an efficient SNARE complex with canonical plasma membrane SNAREs. VAMP4 has unusually high synaptic turnover and is selectively sorted to endolysosomes during activity-dependent bulk endocytosis. Disruption of endolysosomal trafficking and function markedly increased the abundance of VAMP4 in the SV pool and inhibited SV fusion. Together, our results unravel a new mechanism for generating SV heterogeneity and control of Pr through coupling of SV recycling to a major clearing system that regulates protein homeostasis.
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Affiliation(s)
- Daniela Ivanova
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland.
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
| | - Katharine L Dobson
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
| | - Akshada Gajbhiye
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne NE2 4HH, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
| | - Daniela Hacker
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
| | - Sila K Ultanir
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Matthias Trost
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne NE2 4HH, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland.
- Muir Maxwell Epilepsy Centre, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, Scotland
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23
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Soykan T, Haucke V, Kuijpers M. Mechanism of synaptic protein turnover and its regulation by neuronal activity. Curr Opin Neurobiol 2021; 69:76-83. [PMID: 33744822 DOI: 10.1016/j.conb.2021.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/23/2022]
Abstract
Neurons are long-lived cells with a complex architecture, in which synapses may be located far away from the cell body and are subject to plastic changes, thereby posing special challenges to the systems that maintain and dynamically regulate the synaptic proteome. These mechanisms include neuronal autophagy and the endolysosome pathway, as well as the ubiquitin/proteasome system, which cooperate in the constitutive and regulated turnover of presynaptic and postsynaptic proteins. Here, we summarize the pathways involved in synaptic protein degradation and the mechanisms underlying their regulation, for example, by neuronal activity, with an emphasis on the presynaptic compartment and outline perspectives for future research. Keywords: Synapse, Synaptic vesicle, Autophagy, Endolysosome, Proteasome, Protein turnover, Protein degradation, Endosome, Lysosome.
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Affiliation(s)
- Tolga Soykan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry, Pharmacy, 14195, Berlin, Germany.
| | - Marijn Kuijpers
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany.
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24
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Kohrs FE, Daumann IM, Pavlovic B, Jin EJ, Kiral FR, Lin SC, Port F, Wolfenberg H, Mathejczyk TF, Linneweber GA, Chan CC, Boutros M, Hiesinger PR. Systematic functional analysis of rab GTPases reveals limits of neuronal robustness to environmental challenges in flies. eLife 2021; 10:59594. [PMID: 33666175 PMCID: PMC8016483 DOI: 10.7554/elife.59594] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 03/04/2021] [Indexed: 12/26/2022] Open
Abstract
Rab GTPases are molecular switches that regulate membrane trafficking in all cells. Neurons have particular demands on membrane trafficking and express numerous Rab GTPases of unknown function. Here, we report the generation and characterization of molecularly defined null mutants for all 26 rab genes in Drosophila. In flies, all rab genes are expressed in the nervous system where at least half exhibit particularly high levels compared to other tissues. Surprisingly, loss of any of these 13 nervous system-enriched Rabs yielded viable and fertile flies without obvious morphological defects. However, all 13 mutants differentially affected development when challenged with different temperatures, or neuronal function when challenged with continuous stimulation. We identified a synaptic maintenance defect following continuous stimulation for six mutants, including an autophagy-independent role of rab26. The complete mutant collection generated in this study provides a basis for further comprehensive studies of Rab GTPases during development and function in vivo.
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Affiliation(s)
- Friederike E Kohrs
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Ilsa-Maria Daumann
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Bojana Pavlovic
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - Eugene Jennifer Jin
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - F Ridvan Kiral
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | | | - Filip Port
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - Heike Wolfenberg
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Thomas F Mathejczyk
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Gerit A Linneweber
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | | | - Michael Boutros
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
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25
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The BAD-BAX-Caspase-3 Cascade Modulates Synaptic Vesicle Pools via Autophagy. J Neurosci 2021; 41:1174-1190. [PMID: 33303681 DOI: 10.1523/jneurosci.0969-20.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 11/20/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022] Open
Abstract
The BAD-BAX-caspase-3 cascade is a canonical apoptosis pathway. Macroautophagy ("autophagy" hereinafter) is a process by which organelles and aggregated proteins are delivered to lysosomes for degradation. Here, we report a new function of the BAD-BAX-caspase-3 cascade and autophagy in the control of synaptic vesicle pools. We found that, in hippocampal neurons of male mice, the BAD-BAX-caspase-3 pathway regulates autophagy, which in turn limits the size of synaptic vesicle pools and influences the kinetics of activity-induced depletion and recovery of synaptic vesicle pools. Moreover, the caspase-autophagy pathway is engaged by fear conditioning to facilitate associative fear learning and memory. This work identifies a new mechanism for controlling synaptic vesicle pools, and a novel, nonapoptotic, presynaptic function of the BAD-BAX-caspase-3 cascade.SIGNIFICANCE STATEMENT Despite the importance of synaptic vesicles for neurons, little is known about how the size of synaptic vesicle pools is maintained under basal conditions and regulated by neural activity. This study identifies a new mechanism for the control of synaptic vesicle pools, and a new, nonapoptotic function of the BAD-BAX-caspase-3 pathway in presynaptic terminals. Additionally, it indicates that autophagy is not only a homeostatic mechanism to maintain the integrity of cells and tissues, but also a process engaged by neural activity to regulate synaptic vesicle pools for optimal synaptic responses, learning, and memory.
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26
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Kulasekaran G, Chaineau M, Piscopo VEC, Verginelli F, Fotouhi M, Girard M, Tang Y, Dali R, Lo R, Stifani S, McPherson PS. An Arf/Rab cascade controls the growth and invasiveness of glioblastoma. J Cell Biol 2021; 220:e202004229. [PMID: 33443570 PMCID: PMC7812876 DOI: 10.1083/jcb.202004229] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 10/27/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
Glioblastoma is the most common and deadly malignant brain cancer. We now demonstrate that loss of function of the endosomal GTPase Rab35 in human brain tumor initiating cells (BTICs) increases glioblastoma growth and decreases animal survival following BTIC implantation in mouse brains. Mechanistically, we identify that the GTPase Arf5 interacts with the guanine nucleotide exchange factor (GEF) for Rab35, DENND1/connecdenn, and allosterically enhances its GEF activity toward Rab35. Knockdown of either Rab35 or Arf5 increases cell migration, invasiveness, and self-renewal in culture and enhances the growth and invasiveness of BTIC-initiated brain tumors in mice. RNAseq of the tumors reveals up-regulation of the tumor-promoting transcription factor SPOCD1, and disruption of the Arf5/Rab35 axis in glioblastoma cells leads to strong activation of the epidermal growth factor receptor, with resulting enhancement of SPOCD1 levels. These discoveries reveal an unexpected cascade between an Arf and a Rab and indicate a role for the cascade, and thus endosomal trafficking, in brain tumors.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Peter S. McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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27
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Abstract
One in three epilepsy cases is drug resistant, and seizures often begin in infancy, when they are life-threatening and when therapeutic options are highly limited. An important tool for prioritizing and validating genes associated with epileptic conditions, which is suitable for large-scale screening, is disease modeling in Drosophila. Approximately two-thirds of disease genes are conserved in Drosophila, and gene-specific fly models exhibit behavioral changes that are related to symptoms of epilepsy. Models are based on behavior readouts, seizure-like attacks and paralysis following stimulation, and neuronal, cell-biological readouts that are in the majority based on changes in nerve cell activity or morphology. In this review, we focus on behavioral phenotypes. Importantly, Drosophila modeling is independent of, and complementary to, other approaches that are computational and based on systems analysis. The large number of known epilepsy-associated gene variants indicates a need for efficient research strategies. We will discuss the status quo of epilepsy disease modelling in Drosophila and describe promising steps towards the development of new drugs to reduce seizure rates and alleviate other epileptic symptoms.
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Affiliation(s)
- Paul Lasko
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, Netherlands
- Department of Biology, McGill University, Montréal, Québec, Canada
| | - Kevin Lüthy
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
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28
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Remsburg C, Testa M, Song JL. Rab35 regulates skeletogenesis and gastrulation by facilitating actin remodeling and vesicular trafficking. Cells Dev 2021; 165:203660. [PMID: 34024337 DOI: 10.1016/j.cdev.2021.203660] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/11/2020] [Accepted: 12/21/2020] [Indexed: 11/15/2022]
Abstract
Rab35 is a small GTPase that regulates plasma membrane to early endosome vesicular trafficking and mediates actin remodeling to form actin-rich cellular structures. While the function of Rab35 in the cellular context has been examined, its role during development has not been well studied. In this study, we take advantage of the sea urchin's high fecundity, external fertilization, and transparent embryos to determine the function of Rab35 during development. We found that loss of function of Rab35 results in defects in skeletogenesis and gastrulation, which were rescued by co-injection of sea urchin Rab35. The loss of Rab35's function results in decreased endocytosis and impaired exocytosis, which may be important for skeletogenesis and gastrulation. Skeletal spicules of Rab35 knockdown embryos have reduced organized actin compared to the control, supporting the notion that Rab35 regulates actin dynamics. In addition, the skeletal and gastrulation defects induced by Rab35 knockdown were rescued by co-injection with Fascin, an actin-bundling protein, indicating that proper actin dynamics play a critical role for both skeletogenesis and gastrulation. Overall, results indicate that through its role in mediating vesicular trafficking and actin remodeling, Rab35 is an important regulator of embryonic structure formation in early development.
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Affiliation(s)
- Carolyn Remsburg
- University of Delaware, Department of Biological Sciences, Newark, DE, USA
| | - Michael Testa
- University of Delaware, Department of Biological Sciences, Newark, DE, USA
| | - Jia L Song
- University of Delaware, Department of Biological Sciences, Newark, DE, USA.
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29
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Kuijpers M, Azarnia Tehran D, Haucke V, Soykan T. The axonal endolysosomal and autophagic systems. J Neurochem 2021; 158:589-602. [PMID: 33372296 DOI: 10.1111/jnc.15287] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/26/2022]
Abstract
Neurons, because of their elaborate morphology and the long distances between distal axons and the soma as well as their longevity, pose special challenges to autophagy and to the endolysosomal system, two of the main degradative routes for turnover of defective proteins and organelles. Autophagosomes sequester cytoplasmic or organellar cargos by engulfing them into their lumen before fusion with degradative lysosomes enriched in neuronal somata and participate in retrograde signaling to the soma. Endosomes are mainly involved in the sorting, recycling, or lysosomal turnover of internalized or membrane-bound macromolecules to maintain axonal membrane homeostasis. Lysosomes and the multiple shades of lysosome-related organelles also serve non-degradative roles, for example, in nutrient signaling and in synapse formation. Recent years have begun to shed light on the distinctive organization of the autophagy and endolysosomal systems in neurons, in particular their roles in axons. We review here our current understanding of the localization, distribution, and growing list of functions of these organelles in the axon in health and disease and outline perspectives for future research.
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Affiliation(s)
- Marijn Kuijpers
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | | | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Freie Universität Berlin, Faculty of Biology, Chemistry, Berlin, Germany.,Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Tolga Soykan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
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30
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Andres-Alonso M, Kreutz MR, Karpova A. Autophagy and the endolysosomal system in presynaptic function. Cell Mol Life Sci 2020; 78:2621-2639. [PMID: 33340068 PMCID: PMC8004491 DOI: 10.1007/s00018-020-03722-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/17/2020] [Accepted: 11/24/2020] [Indexed: 12/11/2022]
Abstract
The complex morphology of neurons, the specific requirements of synaptic neurotransmission and the accompanying metabolic demands create a unique challenge for proteostasis. The main machineries for neuronal protein synthesis and degradation are localized in the soma, while synaptic junctions are found at vast distances from the cell body. Sophisticated mechanisms must, therefore, ensure efficient delivery of newly synthesized proteins and removal of faulty proteins. These requirements are exacerbated at presynaptic sites, where the demands for protein turnover are especially high due to synaptic vesicle release and recycling that induces protein damage in an intricate molecular machinery, and where replacement of material is hampered by the extreme length of the axon. In this review, we will discuss the contribution of the two major pathways in place, autophagy and the endolysosomal system, to presynaptic protein turnover and presynaptic function. Although clearly different in their biogenesis, both pathways are characterized by cargo collection and transport into distinct membrane-bound organelles that eventually fuse with lysosomes for cargo degradation. We summarize the available evidence with regard to their degradative function, their regulation by presynaptic machinery and the cargo for each pathway. Finally, we will discuss the interplay of both pathways in neurons and very recent findings that suggest non-canonical functions of degradative organelles in synaptic signalling and plasticity.
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Affiliation(s)
- Maria Andres-Alonso
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.
| | - Anna Karpova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
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31
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Giovedì S, Ravanelli MM, Parisi B, Bettegazzi B, Guarnieri FC. Dysfunctional Autophagy and Endolysosomal System in Neurodegenerative Diseases: Relevance and Therapeutic Options. Front Cell Neurosci 2020; 14:602116. [PMID: 33390907 PMCID: PMC7773602 DOI: 10.3389/fncel.2020.602116] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022] Open
Abstract
Autophagy and endolysosomal trafficking are crucial in neuronal development, function and survival. These processes ensure efficient removal of misfolded aggregation-prone proteins and damaged organelles, such as dysfunctional mitochondria, thus allowing the maintenance of proper cellular homeostasis. Beside this, emerging evidence has pointed to their involvement in the regulation of the synaptic proteome needed to guarantee an efficient neurotransmitter release and synaptic plasticity. Along this line, an intimate interplay between the molecular machinery regulating synaptic vesicle endocytosis and synaptic autophagy is emerging, suggesting that synaptic quality control mechanisms need to be tightly coupled to neurosecretion to secure release accuracy. Defects in autophagy and endolysosomal pathway have been associated with neuronal dysfunction and extensively reported in Alzheimer's, Parkinson's, Huntington's and amyotrophic lateral sclerosis among other neurodegenerative diseases, with common features and emerging genetic bases. In this review, we focus on the multiple roles of autophagy and endolysosomal system in neuronal homeostasis and highlight how their defects probably contribute to synaptic default and neurodegeneration in the above-mentioned diseases, discussing the most recent options explored for therapeutic interventions.
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Affiliation(s)
- Silvia Giovedì
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Margherita Maria Ravanelli
- Vita-Salute San Raffaele University, Milan, Italy.,Division of Neuroscience, Neuropsychopharmacology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Barbara Parisi
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Barbara Bettegazzi
- Vita-Salute San Raffaele University, Milan, Italy.,Division of Neuroscience, Gene Therapy of Neurodegenerative Diseases Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Fabrizia Claudia Guarnieri
- Vita-Salute San Raffaele University, Milan, Italy.,Division of Neuroscience, Neuropsychopharmacology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Institute of Neuroscience, National Research Council (CNR), Milan, Italy
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32
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Rozés-Salvador V, González-Billault C, Conde C. The Recycling Endosome in Nerve Cell Development: One Rab to Rule Them All? Front Cell Dev Biol 2020; 8:603794. [PMID: 33425908 PMCID: PMC7793921 DOI: 10.3389/fcell.2020.603794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/11/2020] [Indexed: 12/13/2022] Open
Abstract
Endocytic recycling is an intracellular process that returns internalized molecules back to the plasma membrane and plays crucial roles not only in the reuse of receptor molecules but also in the remodeling of the different components of this membrane. This process is required for a diversity of cellular events, including neuronal morphology acquisition and functional regulation, among others. The recycling endosome (RE) is a key vesicular component involved in endocytic recycling. Recycling back to the cell surface may occur with the participation of several different Rab proteins, which are master regulators of membrane/protein trafficking in nerve cells. The RE consists of a network of interconnected and functionally distinct tubular subdomains that originate from sorting endosomes and transport their cargoes along microtubule tracks, by fast or slow recycling pathways. Different populations of REs, particularly those formed by Rab11, Rab35, and Arf6, are associated with a myriad of signaling proteins. In this review, we discuss the cumulative evidence suggesting the existence of heterogeneous domains of REs, controlling different aspects of neurogenesis, with a particular focus on the commonalities and singularities of these REs and their contribution to nerve development and differentiation in several animal models.
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Affiliation(s)
- Victoria Rozés-Salvador
- Instituto de Investigación Médica Mercedes y Martín Ferreyra INIMEC-CONICET-UNC, Córdoba, Argentina.,Instituto de Ciencias Básicas, Universidad Nacional de Villa María, Córdoba, Argentina
| | - Christian González-Billault
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile.,Department of Neurosciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism, Santiago, Chile.,The Buck Institute for Research on Aging, Novato, CA, United States
| | - Cecilia Conde
- Instituto de Investigación Médica Mercedes y Martín Ferreyra INIMEC-CONICET-UNC, Córdoba, Argentina
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33
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Beauregard-Lacroix E, Pacheco-Cuellar G, Ajeawung NF, Tardif J, Dieterich K, Dabir T, Vind-Kezunovic D, White SM, Zadori D, Castiglioni C, Tranebjærg L, Tørring PM, Blair E, Wisniewska M, Camurri MV, van Bever Y, Molidperee S, Taylor J, Dionne-Laporte A, Sisodiya SM, Hennekam RCM, Campeau PM. DOORS syndrome and a recurrent truncating ATP6V1B2 variant. Genet Med 2020; 23:149-154. [PMID: 32873933 DOI: 10.1038/s41436-020-00950-9] [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] [Received: 06/06/2020] [Revised: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Biallelic variants in TBC1D24, which encodes a protein that regulates vesicular transport, are frequently identified in patients with DOORS (deafness, onychodystrophy, osteodystrophy, intellectual disability [previously referred to as mental retardation], and seizures) syndrome. The aim of the study was to identify a genetic cause in families with DOORS syndrome and without a TBC1D24 variant. METHODS Exome or Sanger sequencing was performed in individuals with a clinical diagnosis of DOORS syndrome without TBC1D24 variants. RESULTS We identified the same truncating variant in ATP6V1B2 (NM_001693.4:c.1516C>T; p.Arg506*) in nine individuals from eight unrelated families with DOORS syndrome. This variant was already reported in individuals with dominant deafness onychodystrophy (DDOD) syndrome. Deafness was present in all individuals, along with onychodystrophy and abnormal fingers and/or toes. All families but one had developmental delay or intellectual disability and five individuals had epilepsy. We also describe two additional families with DDOD syndrome in whom the same variant was found. CONCLUSION We expand the phenotype associated with ATP6V1B2 and propose another causal gene for DOORS syndrome. This finding suggests that DDOD and DOORS syndromes might lie on a spectrum of clinically and molecularly related conditions.
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Affiliation(s)
- Eliane Beauregard-Lacroix
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Guillermo Pacheco-Cuellar
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Norbert F Ajeawung
- CHU Sainte Justine Research Center, Université de Montréal, Montreal, QC, Canada
| | - Jessica Tardif
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Klaus Dieterich
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences (GIN), Grenoble, France
| | - Tabib Dabir
- Department of Genetic Medicine, Belfast City Hospital, Belfast, Northern Ireland, UK
| | - Dina Vind-Kezunovic
- Department of Dermatology, Copenhagen University Hospital Bispebjerg, Copenhagen, NV, Denmark
| | - Susan M White
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Denes Zadori
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | | | - Lisbeth Tranebjærg
- The Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Ed Blair
- Oxford Regional Genetics Service, Oxford University Hospitals, Oxford, UK
| | - Marzena Wisniewska
- Department of Medical Genetics, Poznañ University of Medical Sciences, Poznañ, Poland
| | - Maria Vittoria Camurri
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Yolande van Bever
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sirinart Molidperee
- CHU Sainte Justine Research Center, Université de Montréal, Montreal, QC, Canada
| | - Juliet Taylor
- Genetic Health Service New Zealand-Northern Hub, Auckland, New Zealand
| | - Alexandre Dionne-Laporte
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Raoul C M Hennekam
- Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Philippe M Campeau
- Medical Genetics Division, Department of Pediatrics, Sainte-Justine University Hospital Center, Montreal, QC, Canada.
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34
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Kim Nguyen NT, Ohbayashi N, Kanaho Y, Funakoshi Y. TBC1D24 regulates recycling of clathrin-independent cargo proteins mediated by tubular recycling endosomes. Biochem Biophys Res Commun 2020; 528:220-226. [PMID: 32475639 DOI: 10.1016/j.bbrc.2020.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/02/2020] [Indexed: 11/19/2022]
Abstract
Many plasma membrane proteins enter cells by clathrin-independent endocytosis (CIE). Rab family small GTPases play pivotal roles in CIE and following intracellular trafficking of cargo proteins. Here, we provide evidence that TBC1D24, which contains an atypical Rab GAP domain, facilitates formation of tubular recycling endosomes (TREs) that are a hallmark of the CIE cargo trafficking pathway in HeLa cells. Overexpression of TBC1D24 in HeLa cells dramatically increased TREs loaded with CIE cargo proteins, while deletion of TBC1D24 impaired TRE formation and delayed the recycling of CIE cargo proteins back to the plasma membrane. We also found that TBC1D24 binds to Rab22A, through which TBC1D24 regulates TRE-mediated CIE cargo recycling. These findings provide insight into regulatory mechanisms for CIE cargo trafficking.
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Affiliation(s)
- Nguyen Thi Kim Nguyen
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Norihiko Ohbayashi
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Yasunori Kanaho
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Yuji Funakoshi
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
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35
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Bonnycastle K, Davenport EC, Cousin MA. Presynaptic dysfunction in neurodevelopmental disorders: Insights from the synaptic vesicle life cycle. J Neurochem 2020; 157:179-207. [PMID: 32378740 DOI: 10.1111/jnc.15035] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
Abstract
The activity-dependent fusion, retrieval and recycling of synaptic vesicles is essential for the maintenance of neurotransmission. Until relatively recently it was believed that most mutations in genes that were essential for this process would be incompatible with life, because of this fundamental role. However, an ever-expanding number of mutations in this very cohort of genes are being identified in individuals with neurodevelopmental disorders, including autism, intellectual disability and epilepsy. This article will summarize the current state of knowledge linking mutations in presynaptic genes to neurodevelopmental disorders by sequentially covering the various stages of the synaptic vesicle life cycle. It will also discuss how perturbations of specific stages within this recycling process could translate into human disease. Finally, it will also provide perspectives on the potential for future therapy that are targeted to presynaptic function.
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Affiliation(s)
- Katherine Bonnycastle
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
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36
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Sawade L, Grandi F, Mignanelli M, Patiño-López G, Klinkert K, Langa-Vives F, Di Guardo R, Echard A, Bolino A, Haucke V. Rab35-regulated lipid turnover by myotubularins represses mTORC1 activity and controls myelin growth. Nat Commun 2020; 11:2835. [PMID: 32503983 PMCID: PMC7275063 DOI: 10.1038/s41467-020-16696-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 05/18/2020] [Indexed: 01/21/2023] Open
Abstract
Inherited peripheral neuropathies (IPNs) represent a broad group of disorders including Charcot-Marie-Tooth (CMT) neuropathies characterized by defects primarily arising in myelin, axons, or both. The molecular mechanisms by which mutations in nearly 100 identified IPN/CMT genes lead to neuropathies are poorly understood. Here we show that the Ras-related GTPase Rab35 controls myelin growth via complex formation with the myotubularin-related phosphatidylinositol (PI) 3-phosphatases MTMR13 and MTMR2, encoded by genes responsible for CMT-types 4B2 and B1 in humans, and found that it downregulates lipid-mediated mTORC1 activation, a pathway known to crucially regulate myelin biogenesis. Targeted disruption of Rab35 leads to hyperactivation of mTORC1 signaling caused by elevated levels of PI 3-phosphates and to focal hypermyelination in vivo. Pharmacological inhibition of phosphatidylinositol 3,5-bisphosphate synthesis or mTORC1 signaling ameliorates this phenotype. These findings reveal a crucial role for Rab35-regulated lipid turnover by myotubularins to repress mTORC1 activity and to control myelin growth. Charcot-Marie-Tooth (CMT) is an inherited peripheral neuropathy. Here, the authors show that Rab35 forms a complex with genes implicated in CMT, MTMR13 and MTMR2, which regulates myelin growth by controlling mTORC1 signaling through lipid turnover.
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Affiliation(s)
- Linda Sawade
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Federica Grandi
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Via Olgettina 60, 20132, Milan, Italy
| | - Marianna Mignanelli
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Via Olgettina 60, 20132, Milan, Italy.,San Raffaele Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy
| | - Genaro Patiño-López
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México, Federico Gómez. C.P, 06720, Ciudad de México, México
| | - Kerstin Klinkert
- Membrane Traffic and Cell Division Lab, Institut Pasteur, UMR3691, CNRS, 25-28 rue du Dr Roux, F-75015, Paris, France.,Sorbonne Université, Collège doctoral, F-75005, Paris, France
| | - Francina Langa-Vives
- Centre d'Ingénierie Génétique Murine, Institut Pasteur, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Roberta Di Guardo
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Via Olgettina 60, 20132, Milan, Italy
| | - Arnaud Echard
- Membrane Traffic and Cell Division Lab, Institut Pasteur, UMR3691, CNRS, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Alessandra Bolino
- Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Via Olgettina 60, 20132, Milan, Italy.
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany. .,Freie Universität Berlin, Faculty of Biology, Chemistry and Pharmacy, 14195, Berlin, Germany. .,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin, NeuroCure Cluster of Excellence, 10117, Berlin, Germany.
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37
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Odierna GL, Kerwin SK, Harris LE, Shin GJE, Lavidis NA, Noakes PG, Millard SS. Dscam2 suppresses synaptic strength through a PI3K-dependent endosomal pathway. J Cell Biol 2020; 219:151621. [PMID: 32259198 PMCID: PMC7265308 DOI: 10.1083/jcb.201909143] [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: 09/24/2019] [Revised: 02/19/2020] [Accepted: 03/05/2020] [Indexed: 11/22/2022] Open
Abstract
Dscam2 is a cell surface protein required for neuronal development in Drosophila; it can promote neural wiring through homophilic recognition that leads to either adhesion or repulsion between neurites. Here, we report that Dscam2 also plays a post-developmental role in suppressing synaptic strength. This function is dependent on one of two distinct extracellular isoforms of the protein and is autonomous to motor neurons. We link the PI3K enhancer, Centaurin gamma 1A, to the Dscam2-dependent regulation of synaptic strength and show that changes in phosphoinositide levels correlate with changes in endosomal compartments that have previously been associated with synaptic strength. Using transmission electron microscopy, we find an increase in synaptic vesicles at Dscam2 mutant active zones, providing a rationale for the increase in synaptic strength. Our study provides the first evidence that Dscam2 can regulate synaptic physiology and highlights how diverse roles of alternative protein isoforms can contribute to unique aspects of brain development and function.
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Affiliation(s)
- G Lorenzo Odierna
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Sarah K Kerwin
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Lucy E Harris
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Grace Ji-Eun Shin
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY
| | - Nickolas A Lavidis
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Peter G Noakes
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - S Sean Millard
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
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38
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Lüthy K, Mei D, Fischer B, De Fusco M, Swerts J, Paesmans J, Parrini E, Lubarr N, Meijer IA, Mackenzie KM, Lee WT, Cittaro D, Aridon P, Schoovaerts N, Versées W, Verstreken P, Casari G, Guerrini R. TBC1D24-TLDc-related epilepsy exercise-induced dystonia: rescue by antioxidants in a disease model. Brain 2020; 142:2319-2335. [PMID: 31257402 DOI: 10.1093/brain/awz175] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/08/2019] [Accepted: 04/25/2019] [Indexed: 11/13/2022] Open
Abstract
Genetic mutations in TBC1D24 have been associated with multiple phenotypes, with epilepsy being the main clinical manifestation. The TBC1D24 protein consists of the unique association of a Tre2/Bub2/Cdc16 (TBC) domain and a TBC/lysin motif domain/catalytic (TLDc) domain. More than 50 missense and loss-of-function mutations have been described and are spread over the entire protein. Through whole genome/exome sequencing we identified compound heterozygous mutations, R360H and G501R, within the TLDc domain, in an index family with a Rolandic epilepsy exercise-induced dystonia phenotype (http://omim.org/entry/608105). A 20-year long clinical follow-up revealed that epilepsy was self-limited in all three affected patients, but exercise-induced dystonia persisted into adulthood in two. Furthermore, we identified three additional sporadic paediatric patients with a remarkably similar phenotype, two of whom had compound heterozygous mutations consisting of an in-frame deletion I81_K84 and an A500V mutation, and the third carried T182M and G511R missense mutations, overall revealing that all six patients harbour a missense mutation in the subdomain of TLDc between residues 500 and 511. We solved the crystal structure of the conserved Drosophila TLDc domain. This allowed us to predict destabilizing effects of the G501R and G511R mutations and, to a lesser degree, of R360H and potentially A500V. Next, we characterized the functional consequences of a strong and a weak TLDc mutation (TBC1D24G501R and TBC1D24R360H) using Drosophila, where TBC1D24/Skywalker regulates synaptic vesicle trafficking. In a Drosophila model neuronally expressing human TBC1D24, we demonstrated that the TBC1D24G501R TLDc mutation causes activity-induced locomotion and synaptic vesicle trafficking defects, while TBC1D24R360H is benign. The neuronal phenotypes of the TBC1D24G501R mutation are consistent with exacerbated oxidative stress sensitivity, which is rescued by treating TBC1D24G501R mutant animals with antioxidants N-acetylcysteine amide or α-tocopherol as indicated by restored synaptic vesicle trafficking levels and sustained behavioural activity. Our data thus show that mutations in the TLDc domain of TBC1D24 cause Rolandic-type focal motor epilepsy and exercise-induced dystonia. The humanized TBC1D24G501R fly model exhibits sustained activity and vesicle transport defects. We propose that the TBC1D24/Sky TLDc domain is a reactive oxygen species sensor mediating synaptic vesicle trafficking rates that, when dysfunctional, causes a movement disorder in patients and flies. The TLDc and TBC domain mutations' response to antioxidant treatment we observed in the animal model suggests a potential for combining antioxidant-based therapeutic approaches to TBC1D24-associated disorders with previously described lipid-altering strategies for TBC domain mutations.
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Affiliation(s)
- Kevin Lüthy
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Davide Mei
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Baptiste Fischer
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | | | - Jef Swerts
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Jone Paesmans
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Naomi Lubarr
- Mount Sinai Beth Israel, Department of Neurology, New York, NY, USA
| | - Inge A Meijer
- Department of Pediatrics and Neurosciences, CHU Sainte-Justine and University of Montreal, Montreal, Canada
| | | | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | | | - Paolo Aridon
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
| | - Nils Schoovaerts
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Wim Versées
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Giorgio Casari
- San Raffaele University, Milan, Italy.,Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy.,IRCCS Fondazione Stella Maris, Pisa, Italy
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39
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Guan Z, Quiñones-Frías MC, Akbergenova Y, Littleton JT. Drosophila Synaptotagmin 7 negatively regulates synaptic vesicle release and replenishment in a dosage-dependent manner. eLife 2020; 9:e55443. [PMID: 32343229 PMCID: PMC7224696 DOI: 10.7554/elife.55443] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/28/2020] [Indexed: 01/03/2023] Open
Abstract
Synchronous neurotransmitter release is triggered by Ca2+ binding to the synaptic vesicle protein Synaptotagmin 1, while asynchronous fusion and short-term facilitation is hypothesized to be mediated by plasma membrane-localized Synaptotagmin 7 (SYT7). We generated mutations in Drosophila Syt7 to determine if it plays a conserved role as the Ca2+ sensor for these processes. Electrophysiology and quantal imaging revealed evoked release was elevated 2-fold. Syt7 mutants also had a larger pool of readily-releasable vesicles, faster recovery following stimulation, and intact facilitation. Syt1/Syt7 double mutants displayed more release than Syt1 mutants alone, indicating SYT7 does not mediate the residual asynchronous release remaining in the absence of SYT1. SYT7 localizes to an internal membrane tubular network within the peri-active zone, but does not enrich at active zones. These findings indicate the two Ca2+ sensor model of SYT1 and SYT7 mediating all phases of neurotransmitter release and facilitation is not applicable at Drosophila synapses.
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Affiliation(s)
- Zhuo Guan
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Monica C Quiñones-Frías
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
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40
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Ye H, Ojelade SA, Li-Kroeger D, Zuo Z, Wang L, Li Y, Gu JYJ, Tepass U, Rodal AA, Bellen HJ, Shulman JM. Retromer subunit, VPS29, regulates synaptic transmission and is required for endolysosomal function in the aging brain. eLife 2020; 9:e51977. [PMID: 32286230 PMCID: PMC7182434 DOI: 10.7554/elife.51977] [Citation(s) in RCA: 32] [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: 09/18/2019] [Accepted: 04/11/2020] [Indexed: 12/13/2022] Open
Abstract
Retromer, including Vps35, Vps26, and Vps29, is a protein complex responsible for recycling proteins within the endolysosomal pathway. Although implicated in both Parkinson's and Alzheimer's disease, our understanding of retromer function in the adult brain remains limited, in part because Vps35 and Vps26 are essential for development. In Drosophila, we find that Vps29 is dispensable for embryogenesis but required for retromer function in aging adults, including for synaptic transmission, survival, and locomotion. Unexpectedly, in Vps29 mutants, Vps35 and Vps26 proteins are normally expressed and associated, but retromer is mislocalized from neuropil to soma with the Rab7 GTPase. Further, Vps29 phenotypes are suppressed by reducing Rab7 or overexpressing the GTPase activating protein, TBC1D5. With aging, retromer insufficiency triggers progressive endolysosomal dysfunction, with ultrastructural evidence of impaired substrate clearance and lysosomal stress. Our results reveal the role of Vps29 in retromer localization and function, highlighting requirements for brain homeostasis in aging.
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Affiliation(s)
- Hui Ye
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | | | - David Li-Kroeger
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
| | - Liping Wang
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
| | - Yarong Li
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | - Jessica YJ Gu
- Department of Cell and Systems Biology, University of TorontoOntarioCanada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of TorontoOntarioCanada
| | | | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Howard Hughes Medical InstituteHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Joshua M Shulman
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Department of Neurology, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
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41
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Tona R, Chen W, Nakano Y, Reyes LD, Petralia RS, Wang YX, Starost MF, Wafa TT, Morell RJ, Cravedi KD, du Hoffmann J, Miyoshi T, Munasinghe JP, Fitzgerald TS, Chudasama Y, Omori K, Pierpaoli C, Banfi B, Dong L, Belyantseva IA, Friedman TB. The phenotypic landscape of a Tbc1d24 mutant mouse includes convulsive seizures resembling human early infantile epileptic encephalopathy. Hum Mol Genet 2020; 28:1530-1547. [PMID: 30602030 DOI: 10.1093/hmg/ddy445] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 12/02/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022] Open
Abstract
Epilepsy, deafness, onychodystrophy, osteodystrophy and intellectual disability are associated with a spectrum of mutations of human TBC1D24. The mechanisms underlying TBC1D24-associated disorders and the functions of TBC1D24 are not well understood. Using CRISPR-Cas9 genome editing, we engineered a mouse with a premature translation stop codon equivalent to human S324Tfs*3, a recessive mutation of TBC1D24 associated with early infantile epileptic encephalopathy (EIEE). Homozygous S324Tfs*3 mice have normal auditory and vestibular functions but show an abrupt onset of spontaneous seizures at postnatal day 15 recapitulating human EIEE. The S324Tfs*3 variant is located in an alternatively spliced micro-exon encoding six perfectly conserved amino acids incorporated postnatally into TBC1D24 protein due to a micro-exon utilization switch. During embryonic and early postnatal development, S324Tfs*3 homozygotes produce predominantly the shorter wild-type TBC1D24 protein isoform that omits the micro-exon. S324Tfs*3 homozygotes show an abrupt onset of seizures at P15 that correlates with a developmental switch to utilization of the micro-exon. A mouse deficient for alternative splice factor SRRM3 impairs incorporation of the Tbc1d24 micro-exon. Wild-type Tbc1d24 mRNA is abundantly expressed in the hippocampus using RNAscope in situ hybridization. Immunogold electron microscopy using a TBC1D24-specific antibody revealed that TBC1D24 is associated with clathrin-coated vesicles and synapses of hippocampal neurons, suggesting a crucial role of TBC1D24 in vesicle trafficking important for neuronal signal transmission. This is the first characterization of a mouse model of human TBC1D24-associated EIEE that can now be used to screen for antiepileptogenic drugs ameliorating TBCID24 seizure disorders.
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Affiliation(s)
- Risa Tona
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA.,Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Wenqian Chen
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Yoko Nakano
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Laura D Reyes
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Matthew F Starost
- Division of Veterinary Resources, National Institutes of Health, Bethesda, MD, USA
| | - Talah T Wafa
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Kevin D Cravedi
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Johann du Hoffmann
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Jeeva P Munasinghe
- Mouse Imaging Facility, In vivo NMR Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Yogita Chudasama
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA.,Section on Behavioral Neuroscience, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Koichi Omori
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Carlo Pierpaoli
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Botond Banfi
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
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42
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Lin L, Lyu Q, Kwan PY, Zhao J, Fan R, Chai A, Lai CSW, Chan YS, Shen X, Lai KO. The epilepsy and intellectual disability-associated protein TBC1D24 regulates the maintenance of excitatory synapses and animal behaviors. PLoS Genet 2020; 16:e1008587. [PMID: 32004315 PMCID: PMC7015432 DOI: 10.1371/journal.pgen.1008587] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 02/12/2020] [Accepted: 12/29/2019] [Indexed: 12/27/2022] Open
Abstract
Perturbation of synapse development underlies many inherited neurodevelopmental disorders including intellectual disability (ID). Diverse mutations on the human TBC1D24 gene are strongly associated with epilepsy and ID. However, the physiological function of TBC1D24 in the brain is not well understood, and there is a lack of genetic mouse model that mimics TBC1D24 loss-of-function for the study of animal behaviors. Here we report that TBC1D24 is present at the postsynaptic sites of excitatory synapses, where it is required for the maintenance of dendritic spines through inhibition of the small GTPase ARF6. Mice subjected to viral-mediated knockdown of TBC1D24 in the adult hippocampus display dendritic spine loss, deficits in contextual fear memory, as well as abnormal behaviors including hyperactivity and increased anxiety. Interestingly, we show that the protein stability of TBC1D24 is diminished by the disease-associated missense mutation that leads to F251L amino acid substitution. We further generate the F251L knock-in mice, and the homozygous mutants show increased neuronal excitability, spontaneous seizure and pre-mature death. Moreover, the heterozygous F251L knock-in mice survive into adulthood but display dendritic spine defects and impaired memory. Our findings therefore uncover a previously uncharacterized postsynaptic function of TBC1D24, and suggest that impaired dendritic spine maintenance contributes to the pathophysiology of individuals harboring TBC1D24 gene mutations. The F251L knock-in mice represent a useful animal model for investigation of the mechanistic link between TBC1D24 loss-of-function and neurodevelopmental disorders.
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Affiliation(s)
- Lianfeng Lin
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Quanwei Lyu
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Pui-Yi Kwan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Junjun Zhao
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Ruolin Fan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Anping Chai
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Cora Sau Wan Lai
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
| | - Ying-Shing Chan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
| | - Xuting Shen
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Kwok-On Lai
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
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43
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Abstract
Defects in membrane trafficking are hallmarks of neurodegeneration. Rab GTPases are key regulators of membrane trafficking. Alterations of Rab GTPases, or the membrane compartments they regulate, are associated with virtually all neuronal activities in health and disease. The observation that many Rab GTPases are associated with neurodegeneration has proven a challenge in the quest for cause and effect. Neurodegeneration can be a direct consequence of a defect in membrane trafficking. Alternatively, changes in membrane trafficking may be secondary consequences or cellular responses. The secondary consequences and cellular responses, in turn, may protect, represent inconsequential correlates or function as drivers of pathology. Here, we attempt to disentangle the different roles of membrane trafficking in neurodegeneration by focusing on selected associations with Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and selected neuropathies. We provide an overview of current knowledge on Rab GTPase functions in neurons and review the associations of Rab GTPases with neurodegeneration with respect to the following classifications: primary cause, secondary cause driving pathology or secondary correlate. This analysis is devised to aid the interpretation of frequently observed membrane trafficking defects in neurodegeneration and facilitate the identification of true causes of pathology.
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Murakami Y, Nguyen TTM, Baratang N, Raju PK, Knaus A, Ellard S, Jones G, Lace B, Rousseau J, Ajeawung NF, Kamei A, Minase G, Akasaka M, Araya N, Koshimizu E, van den Ende J, Erger F, Altmüller J, Krumina Z, Strautmanis J, Inashkina I, Stavusis J, El-Gharbawy A, Sebastian J, Puri RD, Kulshrestha S, Verma IC, Maier EM, Haack TB, Israni A, Baptista J, Gunning A, Rosenfeld JA, Liu P, Joosten M, Rocha ME, Hashem MO, Aldhalaan HM, Alkuraya FS, Miyatake S, Matsumoto N, Krawitz PM, Rossignol E, Kinoshita T, Campeau PM. Mutations in PIGB Cause an Inherited GPI Biosynthesis Defect with an Axonal Neuropathy and Metabolic Abnormality in Severe Cases. Am J Hum Genet 2019; 105:384-394. [PMID: 31256876 PMCID: PMC6698938 DOI: 10.1016/j.ajhg.2019.05.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/28/2019] [Indexed: 11/15/2022] Open
Abstract
Proteins anchored to the cell surface via glycosylphosphatidylinositol (GPI) play various key roles in the human body, particularly in development and neurogenesis. As such, many developmental disorders are caused by mutations in genes involved in the GPI biosynthesis and remodeling pathway. We describe ten unrelated families with bi-allelic mutations in PIGB, a gene that encodes phosphatidylinositol glycan class B, which transfers the third mannose to the GPI. Ten different PIGB variants were found in these individuals. Flow cytometric analysis of blood cells and fibroblasts from the affected individuals showed decreased cell surface presence of GPI-anchored proteins. Most of the affected individuals have global developmental and/or intellectual delay, all had seizures, two had polymicrogyria, and four had a peripheral neuropathy. Eight children passed away before four years old. Two of them had a clinical diagnosis of DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures), a condition that includes sensorineural deafness, shortened terminal phalanges with small finger and toenails, intellectual disability, and seizures; this condition overlaps with the severe phenotypes associated with inherited GPI deficiency. Most individuals tested showed elevated alkaline phosphatase, which is a characteristic of the inherited GPI deficiency but not DOORS syndrome. It is notable that two severely affected individuals showed 2-oxoglutaric aciduria, which can be seen in DOORS syndrome, suggesting that severe cases of inherited GPI deficiency and DOORS syndrome might share some molecular pathway disruptions.
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Affiliation(s)
- Yoshiko Murakami
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Thi Tuyet Mai Nguyen
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Nissan Baratang
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Praveen K Raju
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Alexej Knaus
- Insitute for Genomic Statistics and Bioinformatics, University Hospital Bonn, 53127 Bonn, Germany
| | - Sian Ellard
- Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Gabriela Jones
- Clinical Genetics Department, Nottingham University Hospitals NHS Trust, Nottingham NGS 1PB, UK
| | - Baiba Lace
- Centre Hospitalier Universitaire de Québec, 2705 Boulevard Laurier, Ville de Québec, QC G1V 4G2, Canada
| | - Justine Rousseau
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Norbert Fonya Ajeawung
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Atsushi Kamei
- Department of Pediatrics, School of Medicine, Iwate Medical University, Morioka, Iwate 020-8505, Japan
| | - Gaku Minase
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | - Manami Akasaka
- Department of Pediatrics, School of Medicine, Iwate Medical University, Morioka, Iwate 020-8505, Japan
| | - Nami Araya
- Department of Pediatrics, School of Medicine, Iwate Medical University, Morioka, Iwate 020-8505, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | | | - Florian Erger
- Institute of Human Genetics, University Hospital of Cologne, and Center for Molecular Medicine, University of Cologne, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany
| | - Zita Krumina
- Deparment of Biology and Microbiology, Riga Stradinš University, Riga, LV-1029, Latvia
| | | | - Inna Inashkina
- Latvian Biomedical Research and Study Centre, Ratsupites Str. 1 k-1, Riga LV-1067, Latvia
| | - Janis Stavusis
- Latvian Biomedical Research and Study Centre, Ratsupites Str. 1 k-1, Riga LV-1067, Latvia
| | - Areeg El-Gharbawy
- Department of Medical Genetics, Children's Hospital of Pittsburgh of University Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Jessica Sebastian
- Department of Medical Genetics, Children's Hospital of Pittsburgh of University Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Samarth Kulshrestha
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Ishwar C Verma
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi 110060, India
| | - Esther M Maier
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, 80337 Munich, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72074 Tübingen, Germany; Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
| | - Anil Israni
- Department of Paediatric Neurology, Leicester Royal Infirmary, Leicester LE1 5WW, UK
| | - Julia Baptista
- Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Adam Gunning
- Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Marieke Joosten
- Dept of Clinical Genetics, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | | | - Mais O Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Hesham M Aldhalaan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | - Peter M Krawitz
- Insitute for Genomic Statistics and Bioinformatics, University Hospital Bonn, 53127 Bonn, Germany
| | - Elsa Rossignol
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada; Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia; Department of Neurosciences, Centre Hospitalier Universitaire Sainte-Justine and University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Taroh Kinoshita
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Philippe M Campeau
- Centre Hospitalier Universitaire Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada; Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine and University of Montreal, Montreal, QC H3T 1C5, Canada.
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45
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Boecker CA, Holzbaur EL. Vesicular degradation pathways in neurons: at the crossroads of autophagy and endo-lysosomal degradation. Curr Opin Neurobiol 2019; 57:94-101. [PMID: 30784982 PMCID: PMC6629518 DOI: 10.1016/j.conb.2019.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/04/2019] [Accepted: 01/10/2019] [Indexed: 12/12/2022]
Abstract
Autophagy and endo-lysosomal degradation are two parallel degradation pathways essential for maintaining neuronal health and function. Autophagosomes and endosomes sequester cellular cargo through different mechanisms, but these pathways converge upon fusion with lysosomes. Both pathways are spatially regulated, with distinct features evident in the soma, axons, and dendrites, possibly as an adaptation to the unique morphology of neurons and the specific demands of each compartment. Relatively little is known about how autophagy and endo-lysosomal degradation interact and how their activities may be coordinated. We review our current understanding of autophagy and endo-lysosomal degradation in neurons, highlighting common features and differences as well as the intersection of these two essential cellular pathways.
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Affiliation(s)
- C Alexander Boecker
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
| | - Erika Lf Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
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46
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Dulovic-Mahlow M, Trinh J, Kandaswamy KK, Braathen GJ, Di Donato N, Rahikkala E, Beblo S, Werber M, Krajka V, Busk ØL, Baumann H, Al-Sannaa NA, Hinrichs F, Affan R, Navot N, Al Balwi MA, Oprea G, Holla ØL, Weiss ME, Jamra RA, Kahlert AK, Kishore S, Tveten K, Vos M, Rolfs A, Lohmann K. De Novo Variants in TAOK1 Cause Neurodevelopmental Disorders. Am J Hum Genet 2019; 105:213-220. [PMID: 31230721 DOI: 10.1016/j.ajhg.2019.05.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 05/08/2019] [Indexed: 02/08/2023] Open
Abstract
De novo variants represent a significant cause of neurodevelopmental delay and intellectual disability. A genetic basis can be identified in only half of individuals who have neurodevelopmental disorders (NDDs); this indicates that additional causes need to be elucidated. We compared the frequency of de novo variants in patient-parent trios with (n = 2,030) versus without (n = 2,755) NDDs. We identified de novo variants in TAOK1 (thousand and one [TAO] amino acid kinase 1), which encodes the serine/threonine-protein kinase TAO1, in three individuals with NDDs but not in persons who did not have NDDs. Through further screening and the use of GeneMatcher, five additional individuals with NDDs were found to have de novo variants. All eight variants were absent from gnomAD (Genome Aggregation Database). The variant carriers shared a non-specific phenotype of developmental delay, and six individuals had additional muscular hypotonia. We established a fibroblast line of one mutation carrier, and we demonstrated that reduced mRNA levels of TAOK1 could be increased upon cycloheximide treatment. These results indicate nonsense-mediated mRNA decay. Further, there was neither detectable phosphorylated TAO1 kinase nor phosphorylated tau in these cells, and mitochondrial morphology was altered. Knockdown of the ortholog gene Tao1 (Tao, CG14217) in Drosophila resulted in delayed early development. The majority of the Tao1-knockdown flies did not survive beyond the third instar larval stage. When compared to control flies, Tao1 knockdown flies revealed changed morphology of the ventral nerve cord and the neuromuscular junctions as well as a decreased number of endings (boutons). Furthermore, mitochondria in mutant flies showed altered distribution and decreased size in axons of motor neurons. Thus, we provide compelling evidence that de novo variants in TAOK1 cause NDDs.
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47
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The effects of proteasome on baseline and methamphetamine-dependent dopamine transmission. Neurosci Biobehav Rev 2019; 102:308-317. [DOI: 10.1016/j.neubiorev.2019.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/29/2019] [Accepted: 05/09/2019] [Indexed: 12/16/2022]
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48
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Finelli MJ, Aprile D, Castroflorio E, Jeans A, Moschetta M, Chessum L, Degiacomi MT, Grasegger J, Lupien-Meilleur A, Bassett A, Rossignol E, Campeau PM, Bowl MR, Benfenati F, Fassio A, Oliver PL. The epilepsy-associated protein TBC1D24 is required for normal development, survival and vesicle trafficking in mammalian neurons. Hum Mol Genet 2019; 28:584-597. [PMID: 30335140 PMCID: PMC6360273 DOI: 10.1093/hmg/ddy370] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/09/2018] [Indexed: 12/16/2022] Open
Abstract
Mutations in the Tre2/Bub2/Cdc16 (TBC)1 domain family member 24 (TBC1D24) gene are associated with a range of inherited neurological disorders, from drug-refractory lethal epileptic encephalopathy and DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, seizures) to non-syndromic hearing loss. TBC1D24 has been implicated in neuronal transmission and maturation, although the molecular function of the gene and the cause of the apparently complex disease spectrum remain unclear. Importantly, heterozygous TBC1D24 mutation carriers have also been reported with seizures, suggesting that haploinsufficiency for TBC1D24 is significant clinically. Here we have systematically investigated an allelic series of disease-associated mutations in neurons alongside a new mouse model to investigate the consequences of TBC1D24 haploinsufficiency to mammalian neurodevelopment and synaptic physiology. The cellular studies reveal that disease-causing mutations that disrupt either of the conserved protein domains in TBC1D24 are implicated in neuronal development and survival and are likely acting as loss-of-function alleles. We then further investigated TBC1D24 haploinsufficiency in vivo and demonstrate that TBC1D24 is also crucial for normal presynaptic function: genetic disruption of Tbc1d24 expression in the mouse leads to an impairment of endocytosis and an enlarged endosomal compartment in neurons with a decrease in spontaneous neurotransmission. These data reveal the essential role for TBC1D24 at the mammalian synapse and help to define common synaptic mechanisms that could underlie the varied effects of TBC1D24 mutations in neurological disease.
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Affiliation(s)
- Mattéa J Finelli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK
| | - Davide Aprile
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Enrico Castroflorio
- Center of Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 9, Genoa, Italy
| | - Alexander Jeans
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Matteo Moschetta
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,Center of Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 9, Genoa, Italy
| | | | | | - Julia Grasegger
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK
| | - Alexis Lupien-Meilleur
- CHU Ste-Justine, Departments of Neurosciences and Pediatrics, Université de Montréal, Montreal, QC, Canada
| | - Andrew Bassett
- Cellular Operations, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Elsa Rossignol
- CHU Ste-Justine, Departments of Neurosciences and Pediatrics, Université de Montréal, Montreal, QC, Canada
| | - Philippe M Campeau
- CHU Ste-Justine, Departments of Neurosciences and Pediatrics, Université de Montréal, Montreal, QC, Canada
| | | | - Fabio Benfenati
- Center of Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 9, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genoa, Italy
| | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK.,MRC Harwell Institute, Harwell, Oxfordshire, UK
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49
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Ackermann F, Schink KO, Bruns C, Izsvák Z, Hamra FK, Rosenmund C, Garner CC. Critical role for Piccolo in synaptic vesicle retrieval. eLife 2019; 8:46629. [PMID: 31074746 PMCID: PMC6541439 DOI: 10.7554/elife.46629] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/09/2019] [Indexed: 12/30/2022] Open
Abstract
Loss of function of the active zone protein Piccolo has recently been linked to a disease, Pontocerebellar Hypoplasia type 3, which causes brain atrophy. Here, we address how Piccolo inactivation in rat neurons adversely affects synaptic function and thus may contribute to neuronal loss. Our analysis shows that Piccolo is critical for the recycling and maintenance of synaptic vesicles. We find that boutons lacking Piccolo have deficits in the Rab5/EEA1 dependent formation of early endosomes and thus the recycling of SVs. Mechanistically, impaired Rab5 function was caused by reduced synaptic recruitment of Pra1, known to interact selectively with the zinc finger domains of Piccolo. Importantly, over-expression of GTPase deficient Rab5 or the Znf1 domain of Piccolo restores the size and recycling of SV pools. These data provide a molecular link between the active zone and endosome sorting at synapses providing hints to how Piccolo contributes to developmental and psychiatric disorders.
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Affiliation(s)
- Frauke Ackermann
- German Center for Neurodegenerative Diseases e.V. (DZNE), Charité Medical University, Berlin, Germany
| | - Kay Oliver Schink
- Center for Cancer Biomedicine, University of Oslo, Norwegian Radium Hospital, Oslo, Norway
| | - Christine Bruns
- German Center for Neurodegenerative Diseases e.V. (DZNE), Charité Medical University, Berlin, Germany
| | - Zsuzsanna Izsvák
- Max-Delbrück Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| | - F Kent Hamra
- Department of Obstetrics and Gynecology, University of Texas Southwestern, Dallas, United States
| | - Christian Rosenmund
- NeuroCure Cluster of Excellence, Neuroscience Research Center, Charité Medical University, Berlin, Germany
| | - Craig Curtis Garner
- German Center for Neurodegenerative Diseases e.V. (DZNE), Charité Medical University, Berlin, Germany
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50
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Parakh S, Perri ER, Jagaraj CJ, Ragagnin AMG, Atkin JD. Rab-dependent cellular trafficking and amyotrophic lateral sclerosis. Crit Rev Biochem Mol Biol 2019; 53:623-651. [PMID: 30741580 DOI: 10.1080/10409238.2018.1553926] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Rab GTPases are becoming increasingly implicated in neurodegenerative disorders, although their role in amyotrophic lateral sclerosis (ALS) has been somewhat overlooked. However, dysfunction of intracellular transport is gaining increasing attention as a pathogenic mechanism in ALS. Many previous studies have focused axonal trafficking, and the extreme length of axons in motor neurons may contribute to their unique susceptibility in this disorder. In contrast, the role of transport defects within the cell body has been relatively neglected. Similarly, whilst Rab GTPases control all intracellular membrane trafficking events, their role in ALS is poorly understood. Emerging evidence now highlights this family of proteins in ALS, particularly the discovery that C9orf72 functions in intra transport in conjunction with several Rab GTPases. Here, we summarize recent updates on cellular transport defects in ALS, with a focus on Rab GTPases and how their dysfunction may specifically target neurons and contribute to pathophysiology. We discuss the molecular mechanisms associated with dysfunction of Rab proteins in ALS. Finally, we also discuss dysfunction in other modes of transport recently implicated in ALS, including nucleocytoplasmic transport and the ER-mitochondrial contact regions (MAM compartment), and speculate whether these may also involve Rab GTPases.
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Affiliation(s)
- S Parakh
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
| | - E R Perri
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
| | - C J Jagaraj
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia
| | - A M G Ragagnin
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia
| | - J D Atkin
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
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