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Yuan X, Wang Y, Li X, Zhong S, Zhou D, Lin X, Fang H, Yang Y, Wang M. Loss-of-function mutation in DDX53 associated with hereditary spastic paraplegia-like disorder. J Mol Med (Berl) 2024; 102:913-926. [PMID: 38753040 DOI: 10.1007/s00109-024-02454-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 06/29/2024]
Abstract
DEAD-box helicase 53 (DDX53) is a member of the DEAD-box protein family of RNA helicases. Unlike other family members that are responsible for RNA metabolism, the biological function of DDX53 and its impact on the human condition are unclear. Herein, we found a full-length DDX53 deletion mutation in a hereditary spastic paraplegia-like (HSP-like) patient with lower extremity spasticity, walking disorder, visual impairment, and lateral ventricular white matter lesions. Bioinformatic analysis revealed that DDX53 was mainly expressed in the cerebellar cortex and may function as a tissue-specific RNA helicase. Transcriptome analysis showed that the expression of multiple brain-associated genes involved in synapse organization, neuron function, and neuromuscular junctions was affected by DDX53 depletion. Moreover, RNA immunoprecipitation sequencing (RIP-seq) analysis showed that DDX53 interacted with 176 genes, and 96 of these genes were associated with the execution of neurofunction, particularly in the regulation of cell projection organization and nervous system development. Collectively, although a more specified cell or animal model is required to fully understand the functional role of DDX53 in the human brain, we report for the first time that the patient with DDX53 defects exhibits HSP-like symptoms and that DDX53 is essential for maintaining neuronal function, with loss-of-function mutation in DDX53 potentially leading to HSP due to impaired RNA metabolism in the nervous system. KEY MESSAGES: DDX53 deficiency was first reported to be associated with HSP disorder. DDX53 exhibited minimal impact on mitochondrial function. DDX53 impaired RNA metabolism in the nervous system.
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Affiliation(s)
- Xiangshu Yuan
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Ya Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Xiyuan Li
- Baylor Genetics, Houston, TX, 77030, USA
| | - Sheng Zhong
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Danyi Zhou
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Xianlong Lin
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Hezhi Fang
- Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China.
| | - Maofeng Wang
- Department of Biomedical Sciences Laboratory, Affiliated Dongyang Hospital of Wenzhou Medical University, Dongyang, 322100, Zhejiang, China.
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Paumier JM, Gowrishankar S. Disruptions in axonal lysosome transport and its contribution to neurological disease. Curr Opin Cell Biol 2024; 89:102382. [PMID: 38905918 DOI: 10.1016/j.ceb.2024.102382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/23/2024] [Accepted: 05/28/2024] [Indexed: 06/23/2024]
Abstract
Lysosomes are central to the maintenance of protein and organelle homeostasis in cells. Optimal lysosome function is particularly critical for neurons which are long-lived, non-dividing and highly polarized with specialized compartments such as axons and dendrites with distinct architecture, cargo, and turnover requirements. In recent years, there has been a growing appreciation for the role played by axonal lysosome transport in regulating neuronal development, its maintenance and functioning. Perturbations to optimal axonal lysosome abundance leading to either strong accumulations or dearth of lysosomes are both linked to altered neuronal health and functioning. In this review we highlight how two critical regulators of axonal lysosome transport and abundance, the small GTPase Arl8 and the adaptor protein JIP3, aid in maintaining axonal lysosome homeostasis and how alterations to their levels and activity could contribute to neurodevelopmental and neurodegenerative diseases.
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Affiliation(s)
- Jean-Michel Paumier
- Department of Anatomy and Cell Biology, University of Illinois Chicago, 808 S Wood St, Chicago, IL 60612, USA
| | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, University of Illinois Chicago, 808 S Wood St, Chicago, IL 60612, USA.
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3
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Orsini A, Santangelo A, Carmignani A, Camporeale A, Massart F, Tyutyusheva N, Peroni DG, Foiadelli T, Ferretti A, Toschi B, Romano S, Bonuccelli A. An Ultra-Rare Mixed Phenotype with Combined AP-4 and ERF Mutations: The First Report in a Pediatric Patient and a Literature Review. Genes (Basel) 2024; 15:436. [PMID: 38674371 PMCID: PMC11049481 DOI: 10.3390/genes15040436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
The adaptor protein 4 (AP-4) constitutes a conserved hetero-tetrameric complex within the family of adaptor protein (AP) complex, crucial for the signal-mediated trafficking of integral membrane proteins. Mutations affecting all subunits of the AP-4 complex have been linked to autosomal-recessive cerebral palsy and a complex hereditary spastic paraparesis (HSP) phenotype. Our report details the case of a 14-year-old boy born to consanguineous parents, presenting psychomotor delay, severe intellectual disability, microcephaly, and trigonocephaly. Despite a history of febrile seizures, subsequent years were devoid of seizures, with normal EEG. Exome sequencing revealed pathogenic variants in both the AP4B1 and ERF genes. Significantly, the patient exhibited features associated with AP4B1 mutations, including distinctive traits such as cranial malformations. The ERF gene variant, linked to craniosynostosis, likely contributes to the observed trigonocephaly. This case represents the initial documentation of a concurrent mutation in the AP4B1 and ERF genes, underscoring the critical role of exome analysis in unraveling complex phenotypes. Understanding these complex genotypes offers valuable insights into broader syndromic conditions, facilitating comprehensive patient management.
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Affiliation(s)
- Alessandro Orsini
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
| | - Andrea Santangelo
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16126 Genoa, Italy
| | - Alessandra Carmignani
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Anna Camporeale
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Francesco Massart
- Pediatric Endocrinology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (F.M.); (N.T.)
| | - Nina Tyutyusheva
- Pediatric Endocrinology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (F.M.); (N.T.)
| | - Diego Giampietro Peroni
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Thomas Foiadelli
- Clinica Pediatrica, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy;
| | - Alessandro Ferretti
- Pediatrics Unit, Neuroscience, Mental Health and Sense Organs (NESMOS) Department, Faculty of Medicine and Psychology, Sapienza University of Rome, 00185 Rome, Italy;
| | - Benedetta Toschi
- Division of Medical Genetics, Department of Medical and Oncological Area, University-Hospital, 56126 Pisa, Italy; (B.T.); (S.R.)
| | - Silvia Romano
- Division of Medical Genetics, Department of Medical and Oncological Area, University-Hospital, 56126 Pisa, Italy; (B.T.); (S.R.)
| | - Alice Bonuccelli
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
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Damiani D, Baggiani M, Della Vecchia S, Naef V, Santorelli FM. Pluripotent Stem Cells as a Preclinical Cellular Model for Studying Hereditary Spastic Paraplegias. Int J Mol Sci 2024; 25:2615. [PMID: 38473862 DOI: 10.3390/ijms25052615] [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: 01/08/2024] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Hereditary spastic paraplegias (HSPs) comprise a family of degenerative diseases mostly hitting descending axons of corticospinal neurons. Depending on the gene and mutation involved, the disease could present as a pure form with limb spasticity, or a complex form associated with cerebellar and/or cortical signs such as ataxia, dysarthria, epilepsy, and intellectual disability. The progressive nature of HSPs invariably leads patients to require walking canes or wheelchairs over time. Despite several attempts to ameliorate the life quality of patients that have been tested, current therapeutical approaches are just symptomatic, as no cure is available. Progress in research in the last two decades has identified a vast number of genes involved in HSP etiology, using cellular and animal models generated on purpose. Although unanimously considered invaluable tools for basic research, those systems are rarely predictive for the establishment of a therapeutic approach. The advent of induced pluripotent stem (iPS) cells allowed instead the direct study of morphological and molecular properties of the patient's affected neurons generated upon in vitro differentiation. In this review, we revisited all the present literature recently published regarding the use of iPS cells to differentiate HSP patient-specific neurons. Most studies have defined patient-derived neurons as a reliable model to faithfully mimic HSP in vitro, discovering original findings through immunological and -omics approaches, and providing a platform to screen novel or repurposed drugs. Thereby, one of the biggest hopes of current HSP research regards the use of patient-derived iPS cells to expand basic knowledge on the disease, while simultaneously establishing new therapeutic treatments for both generalized and personalized approaches in daily medical practice.
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Affiliation(s)
- Devid Damiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Matteo Baggiani
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Stefania Della Vecchia
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Valentina Naef
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
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Štepihar D, Florke Gee RR, Hoyos Sanchez MC, Fon Tacer K. Cell-specific secretory granule sorting mechanisms: the role of MAGEL2 and retromer in hypothalamic regulated secretion. Front Cell Dev Biol 2023; 11:1243038. [PMID: 37799273 PMCID: PMC10548473 DOI: 10.3389/fcell.2023.1243038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Intracellular protein trafficking and sorting are extremely arduous in endocrine and neuroendocrine cells, which synthesize and secrete on-demand substantial quantities of proteins. To ensure that neuroendocrine secretion operates correctly, each step in the secretion pathways is tightly regulated and coordinated both spatially and temporally. At the trans-Golgi network (TGN), intrinsic structural features of proteins and several sorting mechanisms and distinct signals direct newly synthesized proteins into proper membrane vesicles that enter either constitutive or regulated secretion pathways. Furthermore, this anterograde transport is counterbalanced by retrograde transport, which not only maintains membrane homeostasis but also recycles various proteins that function in the sorting of secretory cargo, formation of transport intermediates, or retrieval of resident proteins of secretory organelles. The retromer complex recycles proteins from the endocytic pathway back to the plasma membrane or TGN and was recently identified as a critical player in regulated secretion in the hypothalamus. Furthermore, melanoma antigen protein L2 (MAGEL2) was discovered to act as a tissue-specific regulator of the retromer-dependent endosomal protein recycling pathway and, by doing so, ensures proper secretory granule formation and maturation. MAGEL2 is a mammalian-specific and maternally imprinted gene implicated in Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. In this review, we will briefly discuss the current understanding of the regulated secretion pathway, encompassing anterograde and retrograde traffic. Although our understanding of the retrograde trafficking and sorting in regulated secretion is not yet complete, we will review recent insights into the molecular role of MAGEL2 in hypothalamic neuroendocrine secretion and how its dysregulation contributes to the symptoms of Prader-Willi and Schaaf-Yang patients. Given that the activation of many secreted proteins occurs after they enter secretory granules, modulation of the sorting efficiency in a tissue-specific manner may represent an evolutionary adaptation to environmental cues.
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Affiliation(s)
- Denis Štepihar
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rebecca R. Florke Gee
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Maria Camila Hoyos Sanchez
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Klementina Fon Tacer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
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6
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Chen X, Dong T, Hu Y, De Pace R, Mattera R, Eberhardt K, Ziegler M, Pirovolakis T, Sahin M, Bonifacino JS, Ebrahimi-Fakhari D, Gray SJ. Intrathecal AAV9/AP4M1 gene therapy for hereditary spastic paraplegia 50 shows safety and efficacy in preclinical studies. J Clin Invest 2023; 133:e164575. [PMID: 36951961 PMCID: PMC10178841 DOI: 10.1172/jci164575] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 03/14/2023] [Indexed: 03/24/2023] Open
Abstract
Spastic paraplegia 50 (SPG50) is an ultrarare childhood-onset neurological disorder caused by biallelic loss-of-function variants in the AP4M1 gene. SPG50 is characterized by progressive spastic paraplegia, global developmental delay, and subsequent intellectual disability, secondary microcephaly, and epilepsy. We preformed preclinical studies evaluating an adeno-associated virus (AAV)/AP4M1 gene therapy for SPG50 and describe in vitro studies that demonstrate transduction of patient-derived fibroblasts with AAV2/AP4M1, resulting in phenotypic rescue. To evaluate efficacy in vivo, Ap4m1-KO mice were intrathecally (i.t.) injected with 5 × 1011, 2.5 × 1011, or 1.25 × 1011 vector genome (vg) doses of AAV9/AP4M1 at P7-P10 or P90. Age- and dose-dependent effects were observed, with early intervention and higher doses achieving the best therapeutic benefits. In parallel, three toxicology studies in WT mice, rats, and nonhuman primates (NHPs) demonstrated that AAV9/AP4M1 had an acceptable safety profile up to a target human dose of 1 × 1015 vg. Of note, similar degrees of minimal-to-mild dorsal root ganglia (DRG) toxicity were observed in both rats and NHPs, supporting the use of rats to monitor DRG toxicity in future i.t. AAV studies. These preclinical results identify an acceptably safe and efficacious dose of i.t.-administered AAV9/AP4M1, supporting an investigational gene transfer clinical trial to treat SPG50.
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Affiliation(s)
- Xin Chen
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Thomas Dong
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Yuhui Hu
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Raffaella De Pace
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Rafael Mattera
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Kathrin Eberhardt
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marvin Ziegler
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Mustafa Sahin
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Juan S. Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Steven J. Gray
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA
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7
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Maciejowski WJ, Gile GH, Jerlström-Hultqvist J, Dacks JB. Ancient and pervasive expansion of adaptin-related vesicle coat machinery across Parabasalia. Int J Parasitol 2023; 53:233-245. [PMID: 36898426 DOI: 10.1016/j.ijpara.2023.01.002] [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: 10/10/2022] [Revised: 01/30/2023] [Accepted: 01/30/2023] [Indexed: 03/11/2023]
Abstract
The eukaryotic phylum Parabasalia is composed primarily of anaerobic, endobiotic organisms such as the veterinary parasite Tritrichomonas foetus and the human parasite Trichomonas vaginalis, the latter causing the most prevalent, non-viral, sexually transmitted disease world-wide. Although a parasitic lifestyle is generally associated with a reduction in cell biology, T. vaginalis provides a striking counter-example. The 2007 T. vaginalis genome paper reported a massive and selective expansion of encoded proteins involved in vesicle trafficking, particularly those implicated in the late secretory and endocytic systems. Chief amongst these were the hetero-tetrameric adaptor proteins or 'adaptins', with T. vaginalis encoding ∼3.5 times more such proteins than do humans. The provenance of such a complement, and how it relates to the transition from a free-living or endobiotic state to parasitism, remains unclear. In this study, we performed a comprehensive bioinformatic and molecular evolutionary investigation of the heterotetrameric cargo adaptor-derived coats, comparing the molecular complement and evolution of these proteins between T. vaginalis, T. foetus and the available diversity of endobiotic parabasalids. Notably, with the recent discovery of Anaeramoeba spp. as the free-living sister lineage to all parabasalids, we were able to delve back to time points earlier in the lineage's history than ever before. We found that, although T. vaginalis still encodes the most HTAC subunits amongst parabasalids, the duplications giving rise to the complement took place more deeply and at various stages across the lineage. While some duplications appear to have convergently shaped the parasitic lineages, the largest jump is in the transition from free-living to endobiotic lifestyle with both gains and losses shaping the encoded complement. This work details the evolution of a cellular system across an important lineage of parasites and provides insight into the evolutionary dynamics of an example of expansion of protein machinery, counter to the more common trends observed in many parasitic systems.
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Affiliation(s)
- William J Maciejowski
- Division of Infectious Diseases, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; Department of Biological Sciences, University of Alberta, Edmonton, Canada; Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Gillian H Gile
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, Arizona, USA
| | - Jon Jerlström-Hultqvist
- Department of Cell and Molecular Biology, BMC, Box 586, Uppsala Universitet, SE-751 24 Uppsala, Sweden. https://twitter.com/jon_hultqvist
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; Department of Biological Sciences, University of Alberta, Edmonton, Canada; Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.
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8
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Moretto E, Miozzo F, Longatti A, Bonnet C, Coussen F, Jaudon F, Cingolani LA, Passafaro M. The tetraspanin TSPAN5 regulates AMPAR exocytosis by interacting with the AP4 complex. eLife 2023; 12:76425. [PMID: 36795458 PMCID: PMC9934860 DOI: 10.7554/elife.76425] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/25/2023] [Indexed: 02/17/2023] Open
Abstract
Intracellular trafficking of AMPA receptors is a tightly regulated process which involves several adaptor proteins, and is crucial for the activity of excitatory synapses both in basal conditions and during synaptic plasticity. We found that, in rat hippocampal neurons, an intracellular pool of the tetraspanin TSPAN5 promotes exocytosis of AMPA receptors without affecting their internalisation. TSPAN5 mediates this function by interacting with the adaptor protein complex AP4 and Stargazin and possibly using recycling endosomes as a delivery route. This work highlights TSPAN5 as a new adaptor regulating AMPA receptor trafficking.
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Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
| | | | | | - Caroline Bonnet
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Francoise Coussen
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Fanny Jaudon
- Department of Life Sciences, University of TriesteTriesteItaly,IRCCS Ospedale Policlinico San MartinoGenoaItaly
| | - Lorenzo A Cingolani
- Department of Life Sciences, University of TriesteTriesteItaly,Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia (IIT)GenoaItaly
| | - Maria Passafaro
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
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9
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Pembridge OG, Wallace NS, Clements TP, Jackson LP. AP-4 loss in CRISPR-edited zebrafish affects early embryo development. Adv Biol Regul 2023; 87:100945. [PMID: 36642642 PMCID: PMC9992121 DOI: 10.1016/j.jbior.2022.100945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Mutations in the heterotetrametric adaptor protein 4 (AP-4; ε/β4/μ4/σ4 subunits) membrane trafficking coat complex lead to complex neurological disorders characterized by spastic paraplegia, microcephaly, and intellectual disabilities. Understanding molecular mechanisms underlying these disorders continues to emerge with recent identification of an essential autophagy protein, ATG9A, as an AP-4 cargo. Significant progress has been made uncovering AP-4 function in cell culture and patient-derived cell lines, and ATG9A trafficking by AP-4 is considered a potential target for gene therapy approaches. In contrast, understanding how AP-4 trafficking affects development and function at the organismal level has long been hindered by loss of conserved AP-4 genes in key model systems (S. cerevisiae, C. elegans, D. melanogaster). However, zebrafish (Danio rerio) have retained AP-4 and can serve as an important model system for studying both the nervous system and overall development. We undertook gene editing in zebrafish using a CRISPR-ExoCas9 knockout system to determine how loss of single AP-4, or its accessory protein tepsin, genes affect embryo development 24 h post-fertilization (hpf). Single gene-edited embryos display abnormal head morphology and neural necrosis. We further conducted the first exploration of how AP-4 single gene knockouts in zebrafish embryos affect expression levels and patterns of two autophagy genes, atg9a and map1lc3b. This work suggests zebrafish may be further adapted and developed as a tool to uncover AP-4 function in membrane trafficking and autophagy in the context of a model organism.
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Affiliation(s)
- Olivia G Pembridge
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Natalie S Wallace
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Thomas P Clements
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
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10
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Buser DP, Spang A. Protein sorting from endosomes to the TGN. Front Cell Dev Biol 2023; 11:1140605. [PMID: 36895788 PMCID: PMC9988951 DOI: 10.3389/fcell.2023.1140605] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/09/2023] [Indexed: 02/23/2023] Open
Abstract
Retrograde transport from endosomes to the trans-Golgi network is essential for recycling of protein and lipid cargoes to counterbalance anterograde membrane traffic. Protein cargo subjected to retrograde traffic include lysosomal acid-hydrolase receptors, SNARE proteins, processing enzymes, nutrient transporters, a variety of other transmembrane proteins, and some extracellular non-host proteins such as viral, plant, and bacterial toxins. Efficient delivery of these protein cargo molecules depends on sorting machineries selectively recognizing and concentrating them for their directed retrograde transport from endosomal compartments. In this review, we outline the different retrograde transport pathways governed by various sorting machineries involved in endosome-to-TGN transport. In addition, we discuss how this transport route can be analyzed experimentally.
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Affiliation(s)
| | - Anne Spang
- Biozentrum, University of Basel, Basel, Switzerland
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11
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Salayev K, Rocca C, Kaiyrzhanov R, Guliyeva U, Guliyeva S, Mursalova A, Rahman F, Anwar N, Zafar F, Jan F, Rana N, Maqbool S, Efthymiou S, Houlden H. AP4B1-associated hereditary spastic paraplegia: Expansion of clinico-genetic phenotype and geographic range. Eur J Med Genet 2022; 65:104620. [PMID: 36122674 DOI: 10.1016/j.ejmg.2022.104620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/22/2022] [Accepted: 09/12/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hereditary spastic paraplegias (HSP) are a group of neurodegenerative diseases that present with weakness and stiffness in the lower limb muscles and lead to progressive neurological decline. Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to complex HSP. This study aimed to identify causative genetic variants in consanguineous families with HSP from Azerbaijan and Pakistan. METHODS We performed a thorough clinical and neuroradiological characterization followed by exome sequencing in 7 patients from 3 unrelated families. Segregation analysis was subsequently performed by Sanger sequencing. RESULTS We describe 7 patients (4 males, 2-31 years of age) with developmental delay and spasticity. Similar to the previously reported cases with AP4B1-associated HSP, cases in the present report besides spasticity in the lower limbs had additional features including microcephaly, facial dysmorphism, infantile hypotonia, and epilepsy. The imaging findings included thin corpus callosum, white matter loss, and ventriculomegaly. CONCLUSION In this study, we report 7 novel cases of HSP caused by bi-allelic variants in AP4B1 in Azerbaijani and Pakistani families. Our observations will help clinicians observe and compare common and unique clinical features of AP4B1-associated HSP patients, further improving our current understanding of HSP.
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Affiliation(s)
- Kamran Salayev
- Azerbaijan Medical University, Department of Neurology, Baku, AZ, 1010, Azerbaijan
| | - Clarissa Rocca
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Rauan Kaiyrzhanov
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Ulviyya Guliyeva
- MediClub Hospital, 45, Uzeyir Hajibeyli Str., Baku, AZ, 1010, Azerbaijan
| | - Sughra Guliyeva
- MediClub Hospital, 45, Uzeyir Hajibeyli Str., Baku, AZ, 1010, Azerbaijan
| | - Aytan Mursalova
- Baku City Gerontologic Centre, Azadliq Ave., Baku, Azerbaijan
| | - Fatima Rahman
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Najwa Anwar
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Faisal Zafar
- Department of Paediatric Neurology, Children's Hospital and Institute of Child Health, Multan, Pakistan
| | - Farida Jan
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan
| | - Nuzhat Rana
- Department of Paediatric Neurology, Children's Hospital and Institute of Child Health, Multan, Pakistan
| | - Shazia Maqbool
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Stephanie Efthymiou
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Henry Houlden
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK.
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12
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Inferring differential subcellular localisation in comparative spatial proteomics using BANDLE. Nat Commun 2022; 13:5948. [PMID: 36216816 PMCID: PMC9550814 DOI: 10.1038/s41467-022-33570-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 09/20/2022] [Indexed: 11/08/2022] Open
Abstract
The steady-state localisation of proteins provides vital insight into their function. These localisations are context specific with proteins translocating between different subcellular niches upon perturbation of the subcellular environment. Differential localisation, that is a change in the steady-state subcellular location of a protein, provides a step towards mechanistic insight of subcellular protein dynamics. High-accuracy high-throughput mass spectrometry-based methods now exist to map the steady-state localisation and re-localisation of proteins. Here, we describe a principled Bayesian approach, BANDLE, that uses these data to compute the probability that a protein differentially localises upon cellular perturbation. Extensive simulation studies demonstrate that BANDLE reduces the number of both type I and type II errors compared to existing approaches. Application of BANDLE to several datasets recovers well-studied translocations. In an application to cytomegalovirus infection, we obtain insights into the rewiring of the host proteome. Integration of other high-throughput datasets allows us to provide the functional context of these data.
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13
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Molecular Mechanism and Regulation of Autophagy and Its Potential Role in Epilepsy. Cells 2022; 11:cells11172621. [PMID: 36078029 PMCID: PMC9455075 DOI: 10.3390/cells11172621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/14/2022] [Accepted: 08/22/2022] [Indexed: 01/18/2023] Open
Abstract
Autophagy is an evolutionally conserved degradation mechanism for maintaining cell homeostasis whereby cytoplasmic components are wrapped in autophagosomes and subsequently delivered to lysosomes for degradation. This process requires the concerted actions of multiple autophagy-related proteins and accessory regulators. In neurons, autophagy is dynamically regulated in different compartments including soma, axons, and dendrites. It determines the turnover of selected materials in a spatiotemporal control manner, which facilitates the formation of specialized neuronal functions. It is not surprising, therefore, that dysfunctional autophagy occurs in epilepsy, mainly caused by an imbalance between excitation and inhibition in the brain. In recent years, much attention has been focused on how autophagy may cause the development of epilepsy. In this article, we overview the historical landmarks and distinct types of autophagy, recent progress in the core machinery and regulation of autophagy, and biological roles of autophagy in homeostatic maintenance of neuronal structures and functions, with a particular focus on synaptic plasticity. We also discuss the relevance of autophagy mechanisms to the pathophysiology of epileptogenesis.
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14
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Majumder P, Edmison D, Rodger C, Patel S, Reid E, Gowrishankar S. AP-4 regulates neuronal lysosome composition, function, and transport via regulating export of critical lysosome receptor proteins at the trans-Golgi network. Mol Biol Cell 2022; 33:ar102. [PMID: 35976706 PMCID: PMC9635302 DOI: 10.1091/mbc.e21-09-0473] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The adaptor protein complex-4 or AP-4 is known to mediate autophagosome maturation through regulating sorting of transmembrane cargo such as ATG9A at the Golgi. There is a need to understand AP-4 function in neurons, as mutations in any of its four subunits cause a complex form of hereditary spastic paraplegia (HSP) with intellectual disability. While AP-4 has been implicated in regulating trafficking and distribution of cargo such as ATG9A and APP, little is known about its effect on neuronal lysosomal protein traffic, lysosome biogenesis and function. In this study, we demonstrate that in human iPSC-derived neurons AP-4 regulates lysosome composition, function and transport via regulating export of critical lysosomal receptors, including Sortilin 1, from the trans-Golgi network to endo-lysosomes. Additionally, loss of AP-4 causes endo-lysosomes to stall and build up in axonal swellings potentially through reduced recruitment of retrograde transport machinery to the organelle. These findings of axonal lysosome build-up are highly reminiscent of those observed in Alzheimer's disease as well as in neurons modelling the most common form of HSP, caused by spastin mutations. Our findings implicate AP-4 as a critical regulator of neuronal lysosome biogenesis and altered lysosome function and axonal endo-lysosome transport as an underlying defect in AP-4 deficient HSP. Additionally, our results also demonstrate the utility of the human i3Neuronal model system in investigating neuronal phenotypes observed in AP-4 deficient mice and/or the human AP-4 deficiency syndrome. [Media: see text] [Media: see text].
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Affiliation(s)
- Piyali Majumder
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Daisy Edmison
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Catherine Rodger
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Sruchi Patel
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Evan Reid
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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15
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Mattera R, De Pace R, Bonifacino JS. The adaptor protein chaperone AAGAB stabilizes AP-4 complex subunits. Mol Biol Cell 2022; 33:ar109. [PMID: 35976721 DOI: 10.1091/mbc.e22-05-0177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Adaptor protein 4 (AP-4) is a heterotetrameric complex composed of ε, β4, μ4 and σ4 subunits that mediates export of a subset of transmembrane cargos, including autophagy protein 9A (ATG9A), from the trans-Golgi network (TGN). AP-4 has received particular attention in recent years because mutations in any of its subunits cause a complicated form of hereditary spastic paraplegia (HSP or SPG) referred to as "AP-4-deficiency syndrome." The identification of proteins that interact with AP-4 has shed light on the mechanisms of AP-4-dependent cargo sorting and distribution within the cell. However, the mechanisms by which the AP-4 complex itself is assembled have remained unknown. Herein, we report that the alpha- and gamma-adaptin-binding protein (AAGAB, also known as p34) binds to and stabilizes the AP-4 ε-and σ4 subunits, thus promoting complex assembly. The importance of this binding is underscored by the observation that AAGAB-knockout cells exhibit reduced levels of AP-4 subunits and accumulation of ATG9A at the TGN like those in cells, mice, or patients with mutations in AP-4-subunit genes. These findings demonstrate that AP-4 assembly is not spontaneous but AAGAB-assisted, thus contributing to the understanding of an adaptor protein complex that is critically involved in development of the central nervous system.
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Affiliation(s)
- Rafael Mattera
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Raffaella De Pace
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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16
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Dahhan DA, Reynolds GD, Cárdenas JJ, Eeckhout D, Johnson A, Yperman K, Kaufmann WA, Vang N, Yan X, Hwang I, Heese A, De Jaeger G, Friml J, Van Damme D, Pan J, Bednarek SY. Proteomic characterization of isolated Arabidopsis clathrin-coated vesicles reveals evolutionarily conserved and plant-specific components. THE PLANT CELL 2022; 34:2150-2173. [PMID: 35218346 DOI: 10.1101/2021.09.16.460678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/22/2022] [Indexed: 05/26/2023]
Abstract
In eukaryotes, clathrin-coated vesicles (CCVs) facilitate the internalization of material from the cell surface as well as the movement of cargo in post-Golgi trafficking pathways. This diversity of functions is partially provided by multiple monomeric and multimeric clathrin adaptor complexes that provide compartment and cargo selectivity. The adaptor-protein assembly polypeptide-1 (AP-1) complex operates as part of the secretory pathway at the trans-Golgi network (TGN), while the AP-2 complex and the TPLATE complex jointly operate at the plasma membrane to execute clathrin-mediated endocytosis. Key to our further understanding of clathrin-mediated trafficking in plants will be the comprehensive identification and characterization of the network of evolutionarily conserved and plant-specific core and accessory machinery involved in the formation and targeting of CCVs. To facilitate these studies, we have analyzed the proteome of enriched TGN/early endosome-derived and endocytic CCVs isolated from dividing and expanding suspension-cultured Arabidopsis (Arabidopsis thaliana) cells. Tandem mass spectrometry analysis results were validated by differential chemical labeling experiments to identify proteins co-enriching with CCVs. Proteins enriched in CCVs included previously characterized CCV components and cargos such as the vacuolar sorting receptors in addition to conserved and plant-specific components whose function in clathrin-mediated trafficking has not been previously defined. Notably, in addition to AP-1 and AP-2, all subunits of the AP-4 complex, but not AP-3 or AP-5, were found to be in high abundance in the CCV proteome. The association of AP-4 with suspension-cultured Arabidopsis CCVs is further supported via additional biochemical data.
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Affiliation(s)
- Dana A Dahhan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Gregory D Reynolds
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jessica J Cárdenas
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Dominique Eeckhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Alexander Johnson
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Klaas Yperman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Walter A Kaufmann
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Nou Vang
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Xu Yan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science & Technology, Pohang 37673, Korea
| | - Antje Heese
- Division of Biochemistry, Interdisciplinary Plant Group, University of Missouri-Columbia, Columbia, Missouri 65211, USA
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jiří Friml
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Daniël Van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jianwei Pan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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17
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Chang SJ, Hsu YT, Chen Y, Lin YY, Lara-Tejero M, Galan JE. Typhoid toxin sorting and exocytic transport from Salmonella Typhi-infected cells. eLife 2022; 11:e78561. [PMID: 35579416 PMCID: PMC9142146 DOI: 10.7554/elife.78561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/15/2022] [Indexed: 11/13/2022] Open
Abstract
Typhoid toxin is an essential virulence factor for Salmonella Typhi, the cause of typhoid fever in humans. This toxin has an unusual biology in that it is produced by Salmonella Typhi only when located within host cells. Once synthesized, the toxin is secreted to the lumen of the Salmonella-containing vacuole from where it is transported to the extracellular space by vesicle carrier intermediates. Here, we report the identification of the typhoid toxin sorting receptor and components of the cellular machinery that packages the toxin into vesicle carriers, and exports it to the extracellular space. We found that the cation-independent mannose-6-phosphate receptor serves as typhoid toxin sorting receptor and that the coat protein COPII and the GTPase Sar1 mediate its packaging into vesicle carriers. Formation of the typhoid toxin carriers requires the specific environment of the Salmonella Typhi-containing vacuole, which is determined by the activities of specific effectors of its type III protein secretion systems. We also found that Rab11B and its interacting protein Rip11 control the intracellular transport of the typhoid toxin carriers, and the SNARE proteins VAMP7, SNAP23, and Syntaxin 4 their fusion to the plasma membrane. Typhoid toxin's cooption of specific cellular machinery for its transport to the extracellular space illustrates the remarkable adaptation of an exotoxin to exert its function in the context of an intracellular pathogen.
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Affiliation(s)
- Shu-Jung Chang
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
- Graduate Institute of Microbiology, College of Medicine, National Taiwan UniversityTaipeiTaiwan
| | - Yu-Ting Hsu
- Graduate Institute of Microbiology, College of Medicine, National Taiwan UniversityTaipeiTaiwan
| | - Yun Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan UniversityTaipeiTaiwan
| | - Yen-Yi Lin
- Graduate Institute of Microbiology, College of Medicine, National Taiwan UniversityTaipeiTaiwan
| | - Maria Lara-Tejero
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Jorge E Galan
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
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18
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Marrone L, Marchi PM, Webster CP, Marroccella R, Coldicott I, Reynolds S, Alves-Cruzeiro J, Yang ZL, Higginbottom A, Khundadze M, Shaw PJ, Hübner CA, Livesey MR, Azzouz M. OUP accepted manuscript. Hum Mol Genet 2022; 31:2693-2710. [PMID: 35313342 PMCID: PMC9402239 DOI: 10.1093/hmg/ddac063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/26/2022] [Accepted: 03/10/2022] [Indexed: 11/26/2022] Open
Abstract
Hereditary spastic paraplegia type 15 (HSP15) is a neurodegenerative condition caused by the inability to produce SPG15 protein, which leads to lysosomal swelling. However, the link between lysosomal aberrations and neuronal death is poorly explored. To uncover the functional consequences of lysosomal aberrations in disease pathogenesis, we analyze human dermal fibroblasts from HSP15 patients as well as primary cortical neurons derived from an SPG15 knockout (KO) mouse model. We find that SPG15 protein loss induces defective anterograde transport, impaired neurite outgrowth, axonal swelling and reduced autophagic flux in association with the onset of lysosomal abnormalities. Additionally, we observe lipid accumulation within the lysosomal compartment, suggesting that distortions in cellular lipid homeostasis are intertwined with lysosomal alterations. We further demonstrate that SPG15 KO neurons exhibit synaptic dysfunction, accompanied by augmented vulnerability to glutamate-induced excitotoxicity. Overall, our study establishes an intimate link between lysosomal aberrations, lipid metabolism and electrophysiological impairments, suggesting that lysosomal defects are at the core of multiple neurodegenerative disease processes in HSP15.
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Affiliation(s)
- Lara Marrone
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
- Department of Neuroscience, Janssen Pharmaceutica, Beerse, Belgium
| | - Paolo M Marchi
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Raffaele Marroccella
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Ian Coldicott
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Steven Reynolds
- Academic Unit of Radiology, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
| | - João Alves-Cruzeiro
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Zih-Liang Yang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Mukhran Khundadze
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Matthew R Livesey
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Mimoun Azzouz
- To whom correspondence should be addressed. Tel: +44 1142222238; Fax: +44 (0)114 2222290; Email
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19
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Elsayed LEO, Eltazi IZ, Ahmed AE, Stevanin G. Insights into Clinical, Genetic, and Pathological Aspects of Hereditary Spastic Paraplegias: A Comprehensive Overview. Front Mol Biosci 2021; 8:690899. [PMID: 34901147 PMCID: PMC8662366 DOI: 10.3389/fmolb.2021.690899] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 10/19/2021] [Indexed: 12/31/2022] Open
Abstract
Hereditary spastic paraplegias (HSP) are a heterogeneous group of motor neurodegenerative disorders that have the core clinical presentation of pyramidal syndrome which starts typically in the lower limbs. They can present as pure or complex forms with all classical modes of monogenic inheritance reported. To date, there are more than 100 loci/88 spastic paraplegia genes (SPG) involved in the pathogenesis of HSP. New patterns of inheritance are being increasingly identified in this era of huge advances in genetic and functional studies. A wide range of clinical symptoms and signs are now reported to complicate HSP with increasing overall complexity of the clinical presentations considered as HSP. This is especially true with the emergence of multiple HSP phenotypes that are situated in the borderline zone with other neurogenetic disorders. The genetic diagnostic approaches and the utilized techniques leave a diagnostic gap of 25% in the best studies. In this review, we summarize the known types of HSP with special focus on those in which spasticity is the principal clinical phenotype ("SPGn" designation). We discuss their modes of inheritance, clinical phenotypes, underlying genetics, and molecular pathways, providing some observations about therapeutic opportunities gained from animal models and functional studies. This review may pave the way for more analytic approaches that take into consideration the overall picture of HSP. It will shed light on subtle associations that can explain the occurrence of the disease and allow a better understanding of its observed variations. This should help in the identification of future biomarkers, predictors of disease onset and progression, and treatments for both better functional outcomes and quality of life.
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Affiliation(s)
- Liena E. O. Elsayed
- Department of Basic Sciences, College of Medicine, Princess Nourah bint Abdulrahman University [PNU], Riyadh, Saudi Arabia
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | | | - Ammar E. Ahmed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Giovanni Stevanin
- Institut du Cerveau – Paris Brain Institute - ICM, Sorbonne Université, INSERM, CNRS, APHP, Paris, France
- CNRS, INCIA, Université de Bordeaux, Bordeaux, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
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20
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Radaszkiewicz T, Nosková M, Gömöryová K, Vondálová Blanářová O, Radaszkiewicz KA, Picková M, Víchová R, Gybeľ T, Kaiser K, Demková L, Kučerová L, Bárta T, Potěšil D, Zdráhal Z, Souček K, Bryja V. RNF43 inhibits WNT5A-driven signaling and suppresses melanoma invasion and resistance to the targeted therapy. eLife 2021; 10:65759. [PMID: 34702444 PMCID: PMC8550759 DOI: 10.7554/elife.65759] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 09/28/2021] [Indexed: 12/30/2022] Open
Abstract
RNF43 is an E3 ubiquitin ligase and known negative regulator of WNT/β-catenin signaling. We demonstrate that RNF43 is also a regulator of noncanonical WNT5A-induced signaling in human cells. Analysis of the RNF43 interactome using BioID and immunoprecipitation showed that RNF43 can interact with the core receptor complex components dedicated to the noncanonical Wnt pathway such as ROR1, ROR2, VANGL1, and VANGL2. RNF43 triggers VANGL2 ubiquitination and proteasomal degradation and clathrin-dependent internalization of ROR1 receptor and inhibits ROR2 activation. These activities of RNF43 are physiologically relevant and block pro-metastatic WNT5A signaling in melanoma. RNF43 inhibits responses to WNT5A, which results in the suppression of invasive properties of melanoma cells. Furthermore, RNF43 prevented WNT5A-assisted development of resistance to BRAF V600E and MEK inhibitors. Next, RNF43 acted as melanoma suppressor and improved response to targeted therapies in vivo. In line with these findings, RNF43 expression decreases during melanoma progression and RNF43-low patients have a worse prognosis. We conclude that RNF43 is a newly discovered negative regulator of WNT5A-mediated biological responses that desensitizes cells to WNT5A.
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Affiliation(s)
- Tomasz Radaszkiewicz
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Michaela Nosková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Kristína Gömöryová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Olga Vondálová Blanářová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | | | - Markéta Picková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic.,International Clinical Research Center FNUSA-ICRC, Brno, Czech Republic
| | - Ráchel Víchová
- Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic
| | - Tomáš Gybeľ
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Karol Kaiser
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lucia Demková
- Laboratory of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lucia Kučerová
- Laboratory of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomáš Bárta
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - David Potěšil
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Karel Souček
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic.,International Clinical Research Center FNUSA-ICRC, Brno, Czech Republic
| | - Vítězslav Bryja
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Department of Cytokinetics, Institute of Biophysics CAS, Brno, Czech Republic
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21
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Ebrahimi-Fakhari D, Alecu JE, Brechmann B, Ziegler M, Eberhardt K, Jumo H, D’Amore A, Habibzadeh P, Faghihi MA, De Bleecker JL, Vuillaumier-Barrot S, Auvin S, Santorelli FM, Neuser S, Popp B, Yang E, Barrett L, Davies AK, Saffari A, Hirst J, Sahin M. High-throughput imaging of ATG9A distribution as a diagnostic functional assay for adaptor protein complex 4-associated hereditary spastic paraplegia. Brain Commun 2021; 3:fcab221. [PMID: 34729478 PMCID: PMC8557665 DOI: 10.1093/braincomms/fcab221] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 01/09/2023] Open
Abstract
Adaptor protein complex 4-associated hereditary spastic paraplegia is caused by biallelic loss-of-function variants in AP4B1, AP4M1, AP4E1 or AP4S1, which constitute the four subunits of this obligate complex. While the diagnosis of adaptor protein complex 4-associated hereditary spastic paraplegia relies on molecular testing, the interpretation of novel missense variants remains challenging. Here, we address this diagnostic gap by using patient-derived fibroblasts to establish a functional assay that measures the subcellular localization of ATG9A, a transmembrane protein that is sorted by adaptor protein complex 4. Using automated high-throughput microscopy, we determine the ratio of the ATG9A fluorescence in the trans-Golgi-network versus cytoplasm and ascertain that this metric meets standards for screening assays (Z'-factor robust >0.3, strictly standardized mean difference >3). The 'ATG9A ratio' is increased in fibroblasts of 18 well-characterized adaptor protein complex 4-associated hereditary spastic paraplegia patients [mean: 1.54 ± 0.13 versus 1.21 ± 0.05 (standard deviation) in controls] and receiver-operating characteristic analysis demonstrates robust diagnostic power (area under the curve: 0.85, 95% confidence interval: 0.849-0.852). Using fibroblasts from two individuals with atypical clinical features and novel biallelic missense variants of unknown significance in AP4B1, we show that our assay can reliably detect adaptor protein complex 4 function. Our findings establish the 'ATG9A ratio' as a diagnostic marker of adaptor protein complex 4-associated hereditary spastic paraplegia.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Julian E Alecu
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Marvin Ziegler
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Ruprecht-Karls University Heidelberg, Medical School, 69120 Heidelberg, Germany
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hellen Jumo
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, 71347 Shiraz, Iran
| | - Mohammad Ali Faghihi
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL 33136, USA
| | - Jan L De Bleecker
- Department of Neurology, Ghent University Hospital, 9000 Ghent, Belgium
| | | | - Stéphane Auvin
- Pediatric Neurology Department, AP-HP, Robert Debré Hospital, 75019 Paris, France
| | - Filippo M Santorelli
- Department of Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Sonja Neuser
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Bernt Popp
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Edward Yang
- Division of Neuroradiology, Department of Radiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Afshin Saffari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
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22
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Protein Sorting in Plasmodium Falciparum. Life (Basel) 2021; 11:life11090937. [PMID: 34575086 PMCID: PMC8467625 DOI: 10.3390/life11090937] [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: 06/30/2021] [Revised: 09/04/2021] [Accepted: 09/04/2021] [Indexed: 11/23/2022] Open
Abstract
Plasmodium falciparum is a unicellular eukaryote with a very polarized secretory system composed of micronemes rhoptries and dense granules that are required for host cell invasion. P. falciparum, like its relative T. gondii, uses the endolysosomal system to produce the secretory organelles and to ingest host cell proteins. The parasite also has an apicoplast, a secondary endosymbiotic organelle, which depends on vesicular trafficking for appropriate incorporation of nuclear-encoded proteins into the apicoplast. Recently, the central molecules responsible for sorting and trafficking in P. falciparum and T. gondii have been characterized. From these studies, it is now evident that P. falciparum has repurposed the molecules of the endosomal system to the secretory pathway. Additionally, the sorting and vesicular trafficking mechanism seem to be conserved among apicomplexans. This review described the most recent findings on the molecular mechanisms of protein sorting and vesicular trafficking in P. falciparum and revealed that P. falciparum has an amazing secretory machinery that has been cleverly modified to its intracellular lifestyle.
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23
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Lujan P, Campelo F. Should I stay or should I go? Golgi membrane spatial organization for protein sorting and retention. Arch Biochem Biophys 2021; 707:108921. [PMID: 34038703 DOI: 10.1016/j.abb.2021.108921] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/12/2021] [Accepted: 05/03/2021] [Indexed: 12/23/2022]
Abstract
The Golgi complex is the membrane-bound organelle that lies at the center of the secretory pathway. Its main functions are to maintain cellular lipid homeostasis, to orchestrate protein processing and maturation, and to mediate protein sorting and export. These functions are not independent of one another, and they all require that the membranes of the Golgi complex have a well-defined biochemical composition. Importantly, a finely-regulated spatiotemporal organization of the Golgi membrane components is essential for the correct performance of the organelle. In here, we review our current mechanistic and molecular understanding of how Golgi membranes are spatially organized in the lateral and axial directions to fulfill their functions. In particular, we highlight the current evidence and proposed models of intra-Golgi transport, as well as the known mechanisms for the retention of Golgi residents and for the sorting and export of transmembrane cargo proteins. Despite the controversies, conflicting evidence, clashes between models, and technical limitations, the field has moved forward and we have gained extensive knowledge in this fascinating topic. However, there are still many important questions that remain to be completely answered. We hope that this review will help boost future investigations on these issues.
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Affiliation(s)
- Pablo Lujan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
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24
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Edmison D, Wang L, Gowrishankar S. Lysosome Function and Dysfunction in Hereditary Spastic Paraplegias. Brain Sci 2021; 11:152. [PMID: 33498913 PMCID: PMC7911997 DOI: 10.3390/brainsci11020152] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/15/2021] [Accepted: 01/21/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary Spastic Paraplegias (HSPs) are a genetically diverse group of inherited neurological diseases with over 80 associated gene loci. Over the last decade, research into mechanisms underlying HSPs has led to an emerging interest in lysosome dysfunction. In this review, we highlight the different classes of HSPs that have been linked to lysosome defects: (1) a subset of complex HSPs where mutations in lysosomal genes are causally linked to the diseases, (2) other complex HSPs where mutation in genes encoding membrane trafficking adaptors lead to lysosomal defects, and (3) a subset of HSPs where mutations affect genes encoding proteins whose function is primarily linked to a different cellular component or organelle such as microtubule severing and Endoplasmic Reticulum-shaping, while also altering to lysosomes. Interestingly, aberrant axonal lysosomes, associated with the latter two subsets of HSPs, are a key feature observed in other neurodegenerative diseases such as Alzheimer's disease. We discuss how altered lysosome function and trafficking may be a critical contributor to HSP pathology and highlight the need for examining these features in the cortico-spinal motor neurons of HSP mutant models.
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Affiliation(s)
| | | | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; (D.E.); (L.W.)
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25
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The role of AP-4 in cargo export from the trans-Golgi network and hereditary spastic paraplegia. Biochem Soc Trans 2020; 48:1877-1888. [PMID: 33084855 DOI: 10.1042/bst20190664] [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: 07/09/2020] [Revised: 09/22/2020] [Accepted: 09/29/2020] [Indexed: 01/02/2023]
Abstract
Heterotetrameric adaptor protein (AP) complexes play key roles in protein sorting and transport vesicle formation in the endomembrane system of eukaryotic cells. One of these complexes, AP-4, was identified over 20 years ago but, up until recently, its function remained unclear. AP-4 associates with the trans-Golgi network (TGN) through interaction with small GTPases of the ARF family and recognizes transmembrane proteins (i.e. cargos) having specific sorting signals in their cytosolic domains. Recent studies identified accessory proteins (tepsin, RUSC2 and the FHF complex) that co-operate with AP-4, and cargos (amyloid precursor protein, ATG9A and SERINC3/5) that are exported from the TGN in an AP-4-dependent manner. Defective export of ATG9A from the TGN in AP-4-deficient cells was shown to reduce ATG9A delivery to pre-autophagosomal structures, impairing autophagosome formation and/or maturation. In addition, mutations in AP-4-subunit genes were found to cause neurological dysfunction in mice and a form of complicated hereditary spastic paraplegia referred to as 'AP-4-deficiency syndrome' in humans. These findings demonstrated that mammalian AP-4 is required for the development and function of the central nervous system, possibly through its role in the sorting of ATG9A for the maintenance of autophagic homeostasis. In this article, we review the properties and functions of AP-4, and discuss how they might explain the clinical features of AP-4 deficiency.
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26
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EPSIN1 and MTV1 define functionally overlapping but molecularly distinct trans-Golgi network subdomains in Arabidopsis. Proc Natl Acad Sci U S A 2020; 117:25880-25889. [PMID: 32989160 DOI: 10.1073/pnas.2004822117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The plant trans-Golgi network (TGN) is a central trafficking hub where secretory, vacuolar, recycling, and endocytic pathways merge. Among currently known molecular players involved in TGN transport, three different adaptor protein (AP) complexes promote vesicle generation at the TGN with different cargo specificity and destination. Yet, it remains unresolved how sorting into diverging vesicular routes is spatially organized. Here, we study the family of Arabidopsis thaliana Epsin-like proteins, which are accessory proteins to APs facilitating vesicle biogenesis. By comprehensive molecular, cellular, and genetic analysis of the EPSIN gene family, we identify EPSIN1 and MODIFIED TRANSPORT TO THE VACUOLE1 (MTV1) as its only TGN-associated members. Despite their large phylogenetic distance, they perform overlapping functions in vacuolar and secretory transport. By probing their relationship with AP complexes, we find that they define two molecularly independent pathways: While EPSIN1 associates with AP-1, MTV1 interacts with AP-4, whose function is required for MTV1 recruitment. Although both EPSIN1/AP-1 and MTV1/AP-4 pairs reside at the TGN, high-resolution microscopy reveals them as spatially separate entities. Our results strongly support the hypothesis of molecularly, functionally, and spatially distinct subdomains of the plant TGN and suggest that functional redundancy can be achieved through parallelization of molecularly distinct but functionally overlapping pathways.
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27
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Two Separate Tyrosine-Based YXXL/Φ Motifs within the Glycoprotein E Cytoplasmic Tail of Bovine Herpesvirus 1 Contribute in Virus Anterograde Neuronal Transport. Viruses 2020; 12:v12091025. [PMID: 32937797 PMCID: PMC7551581 DOI: 10.3390/v12091025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/31/2020] [Accepted: 09/12/2020] [Indexed: 12/30/2022] Open
Abstract
Bovine herpesvirus 1 (BHV-1) causes respiratory infection and abortion in cattle. Following a primary infection, BHV-1 establishes lifelong latency in the trigeminal ganglia (TG). Periodic reactivation of the latent virus in TG neurons results in anterograde virus transport to nerve endings in the nasal mucosa and nasal virus shedding. The BHV-1 glycoprotein E cytoplasmic tail (gE-CT) is necessary for virus cell-to-cell spread in epithelial cells and neuronal anterograde transport. Recently, we identified two tyrosine residues, Y467 and Y563, within the tyrosine-based motifs 467YTSL470 and 563YTVV566, which, together, account for the gE CT-mediated efficient cell-to-cell spread of BHV-1 in epithelial cells. Here, we determined that in primary neuron cultures in vitro, the individual alanine exchange Y467A or Y563A mutants had significantly diminished anterograde axonal spread. Remarkably, the double-alanine-exchanged Y467A/Y563A mutant virus was not transported anterogradely. Following intranasal infection of rabbits, both wild-type (wt) and the Y467A/Y563A mutant viruses established latency in the TG. Upon dexamethasone-induced reactivation, both wt and the mutant viruses reactivated and replicated equally efficiently in the TG. However, upon reactivation, only the wt, not the mutant, was isolated from nasal swabs. Therefore, the gE-CT tyrosine residues Y467 and Y563 together are required for gE CT-mediated anterograde neuronal transport.
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28
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Beheshtian M, Akhtarkhavari T, Mehvari S, Mohseni M, Fattahi Z, Abedini SS, Arzhangi S, Fadaee M, Jamali P, Najafipour R, Kalscheuer VM, Hu H, Ropers HH, Najmabadi H, Kahrizi K. Comprehensive genotype-phenotype correlation in AP-4 deficiency syndrome; Adding data from a large cohort of Iranian patients. Clin Genet 2020; 99:187-192. [PMID: 32895917 DOI: 10.1111/cge.13845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/21/2020] [Accepted: 09/02/2020] [Indexed: 12/25/2022]
Abstract
Mutations in adaptor protein complex-4 (AP-4) genes have first been identified in 2009, causing a phenotype termed as AP-4 deficiency syndrome. Since then several patients with overlapping phenotypes, comprised of intellectual disability (ID) and spastic tetraplegia have been reported. To delineate the genotype-phenotype correlation of the AP-4 deficiency syndrome, we add the data from 30 affected individuals from 12 out of 640 Iranian families with ID in whom we detected disease-causing variants in AP-4 complex subunits, using next-generation sequencing. Furthermore, by comparing genotype-phenotype findings of those affected individuals with previously reported patients, we further refine the genotype-phenotype correlation in this syndrome. The most frequent reported clinical findings in the 101 cases consist of ID and/or global developmental delay (97%), speech disorders (92.1%), inability to walk (90.1%), spasticity (77.2%), and microcephaly (75.2%). Spastic tetraplegia has been reported in 72.3% of the investigated patients. The major brain imaging findings are abnormal corpus callosum morphology (63.4%) followed by ventriculomegaly (44.5%). Our result might suggest the AP-4 deficiency syndrome as a major differential diagnostic for unknown hereditary neurodegenerative disorders.
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Affiliation(s)
- Maryam Beheshtian
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Tara Akhtarkhavari
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Sepideh Mehvari
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Marzieh Mohseni
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Seyedeh Sedigheh Abedini
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Sanaz Arzhangi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mahsa Fadaee
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Payman Jamali
- Genetic Counseling Center, Shahroud Welfare Organization, Semnan, Iran
| | - Reza Najafipour
- Cellular and Molecular Research Centre, Genetic Department, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Vera M Kalscheuer
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Hao Hu
- Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Hans-Hilger Ropers
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany.,Institute for Human Genetics, University Medicine, Mainz, Germany
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.,Kariminejad - Najmabadi Pathology and Genetics Center, Molecular division, Tehran, Islamic Republic of Iran, Tehran, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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29
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Gadbery JE, Abraham A, Needle CD, Moth C, Sheehan J, Capra JA, Jackson LP. Integrating structural and evolutionary data to interpret variation and pathogenicity in adapter protein complex 4. Protein Sci 2020; 29:1535-1549. [PMID: 32285480 PMCID: PMC7255511 DOI: 10.1002/pro.3870] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/01/2020] [Accepted: 04/10/2020] [Indexed: 12/13/2022]
Abstract
Genetic variation in the membrane trafficking adapter protein complex 4 (AP-4) can result in pathogenic neurological phenotypes including microencephaly, spastic paraplegias, epilepsy, and other developmental defects. We lack molecular mechanisms responsible for impaired AP-4 function arising from genetic variation, because AP-4 remains poorly understood structurally. Here, we analyze patterns of AP-4 genetic evolution and conservation to identify regions that are likely important for function and thus more susceptible to pathogenic variation. We map known variants onto an AP-4 homology model and predict the likelihood of pathogenic variation at a given location on the structure of AP-4. We find significant clustering of likely pathogenic variants located at the interface between the β4 and N-μ4 subunits, as well as throughout the C-μ4 subunit. Our work offers an integrated perspective on how genetic and evolutionary forces affect AP-4 structure and function. As more individuals with uncharacterized AP-4 variants are identified, our work provides a foundation upon which their functional effects and disease relevance can be interpreted.
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Affiliation(s)
- John E. Gadbery
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Abin Abraham
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Carli D. Needle
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Christopher Moth
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - Jonathan Sheehan
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - John A. Capra
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of Biomedical InformaticsVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Lauren P. Jackson
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
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30
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Szczałuba K, Mierzewska H, Śmigiel R, Kosińska J, Koppolu A, Biernacka A, Stawiński P, Pollak A, Rydzanicz M, Płoski R. AP4B1-associated hereditary spastic paraplegia: expansion of phenotypic spectrum related to homozygous p.Thr387fs variant. J Appl Genet 2020; 61:213-218. [PMID: 32166732 PMCID: PMC7148264 DOI: 10.1007/s13353-020-00552-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/05/2020] [Accepted: 02/12/2020] [Indexed: 11/11/2022]
Abstract
Biallelic mutations in the AP4B1 gene, encoding adaptor-related protein complex 4 beta-1 subunit, have been recognized as an important cause of a group of conditions leading to adaptor-related protein complex 4 (AP4)-associated hereditary spastic paraplegia (SPG47). We describe a homozygous, known variant c.1160_1161delCA (p.Thr387fs) that was found in the largest ever group of patients coming from four families. The patients exhibited early hypotonia progressing to spastic paraplegia, microcephaly, epilepsy, and central nervous system (CNS) defects and global developmental delay that are consistent with the nature of SPG47. Our findings expand phenotypic spectrum of SPG47 to include polymorphic seizures, mild/moderate intellectual disability, and intracerebral cysts as well as point to founder mutation in AP4 deficiency disorders in apparently non-consanguineous Polish families without shared ancestry.
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Affiliation(s)
- Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Hanna Mierzewska
- Department of Child and Adolescent Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Robert Śmigiel
- Department of Paediatrics, Division of Paediatric Propaedeutics and Rare Disorders, Wroclawa Medical University, Wroclaw, Poland
| | - Joanna Kosińska
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Agnieszka Koppolu
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Warsaw, Poland
| | - Anna Biernacka
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Warsaw, Poland
| | - Piotr Stawiński
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Department of Genetics, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.
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31
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Behne R, Teinert J, Wimmer M, D’Amore A, Davies AK, Scarrott JM, Eberhardt K, Brechmann B, Chen IPF, Buttermore ED, Barrett L, Dwyer S, Chen T, Hirst J, Wiesener A, Segal D, Martinuzzi A, Duarte ST, Bennett JT, Bourinaris T, Houlden H, Roubertie A, Santorelli FM, Robinson M, Azzouz M, Lipton JO, Borner GHH, Sahin M, Ebrahimi-Fakhari D. Adaptor protein complex 4 deficiency: a paradigm of childhood-onset hereditary spastic paraplegia caused by defective protein trafficking. Hum Mol Genet 2020; 29:320-334. [PMID: 31915823 PMCID: PMC7001721 DOI: 10.1093/hmg/ddz310] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Accepted: 12/05/2019] [Indexed: 12/25/2022] Open
Abstract
Deficiency of the adaptor protein complex 4 (AP-4) leads to childhood-onset hereditary spastic paraplegia (AP-4-HSP): SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). This study aims to evaluate the impact of loss-of-function variants in AP-4 subunits on intracellular protein trafficking using patient-derived cells. We investigated 15 patient-derived fibroblast lines and generated six lines of induced pluripotent stem cell (iPSC)-derived neurons covering a wide range of AP-4 variants. All patient-derived fibroblasts showed reduced levels of the AP4E1 subunit, a surrogate for levels of the AP-4 complex. The autophagy protein ATG9A accumulated in the trans-Golgi network and was depleted from peripheral compartments. Western blot analysis demonstrated a 3-5-fold increase in ATG9A expression in patient lines. ATG9A was redistributed upon re-expression of AP4B1 arguing that mistrafficking of ATG9A is AP-4-dependent. Examining the downstream effects of ATG9A mislocalization, we found that autophagic flux was intact in patient-derived fibroblasts both under nutrient-rich conditions and when autophagy is stimulated. Mitochondrial metabolism and intracellular iron content remained unchanged. In iPSC-derived cortical neurons from patients with AP4B1-associated SPG47, AP-4 subunit levels were reduced while ATG9A accumulated in the trans-Golgi network. Levels of the autophagy marker LC3-II were reduced, suggesting a neuron-specific alteration in autophagosome turnover. Neurite outgrowth and branching were reduced in AP-4-HSP neurons pointing to a role of AP-4-mediated protein trafficking in neuronal development. Collectively, our results establish ATG9A mislocalization as a key marker of AP-4 deficiency in patient-derived cells, including the first human neuron model of AP-4-HSP, which will aid diagnostic and therapeutic studies.
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Affiliation(s)
- Robert Behne
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Julian Teinert
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Miriam Wimmer
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Molecular Medicine, IRCCS Fondazione Stella Maris, 56018 Pisa, Italy
| | - Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Joseph M Scarrott
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ivy Pin-Fang Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth D Buttermore
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sean Dwyer
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Teresa Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Antje Wiesener
- Institute of Human Genetics, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Devorah Segal
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York City, NY 10021, USA
| | - Andrea Martinuzzi
- Scientific Institute, IRCCS E. Medea, Unità Operativa Conegliano, 31015 Treviso, Italy
| | - Sofia T Duarte
- Department of Pediatric Neurology, Centro Hospitalar de Lisboa Central, 1169-050 Lisbon, Portugal
| | - James T Bennett
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Thomas Bourinaris
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | | | | | - Margaret Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mimoun Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Jonathan O Lipton
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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32
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Belgrad J, De Pace R, Fields RD. Autophagy in Myelinating Glia. J Neurosci 2020; 40:256-266. [PMID: 31744863 PMCID: PMC6948934 DOI: 10.1523/jneurosci.1066-19.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/17/2019] [Accepted: 11/08/2019] [Indexed: 12/14/2022] Open
Abstract
Autophagy is the cellular process involved in transportation and degradation of membrane, proteins, pathogens, and organelles. This fundamental cellular process is vital in development, plasticity, and response to disease and injury. Compared with neurons, little information is available on autophagy in glia, but it is paramount for glia to perform their critical responses to nervous system disease and injury, including active tissue remodeling and phagocytosis. In myelinating glia, autophagy has expanded roles, particularly in phagocytosis of mature myelin and in generating the vast amounts of membrane proteins and lipids that must be transported to form new myelin. Notably, autophagy plays important roles in removing excess cytoplasm to promote myelin compaction and development of oligodendrocytes, as well as in remyelination by Schwann cells after nerve trauma. This review summarizes the cell biology of autophagy, detailing the major pathways and proteins involved, as well as the roles of autophagy in Schwann cells and oligodendrocytes in development, plasticity, and diseases in which myelin is affected. This includes traumatic brain injury, Alexander's disease, Alzheimer's disease, hypoxia, multiple sclerosis, hereditary spastic paraplegia, and others. Promising areas for future research are highlighted.
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Affiliation(s)
| | - Raffaella De Pace
- Section on Intracellular Protein Trafficking, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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Teinert J, Behne R, Wimmer M, Ebrahimi-Fakhari D. Novel insights into the clinical and molecular spectrum of congenital disorders of autophagy. J Inherit Metab Dis 2020; 43:51-62. [PMID: 30854657 DOI: 10.1002/jimd.12084] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/07/2019] [Indexed: 12/24/2022]
Abstract
Autophagy is a fundamental and conserved catabolic pathway that mediates the degradation of macromolecules and organelles in lysosomes. Autophagy is particularly important to postmitotic and metabolically active cells such as neurons. The complex architecture of neurons and their long axons pose additional challenges for efficient recycling of cargo. Not surprisingly autophagy is required for normal central nervous system development and function. Several single-gene disorders of the autophagy pathway have been discovered in recent years giving rise to a novel group of inborn errors of metabolism referred to as congenital disorders of autophagy. While these disorders are heterogeneous, they share several clinical and molecular characteristics including a prominent and progressive involvement of the central nervous system leading to brain malformations, developmental delay, intellectual disability, epilepsy, movement disorders, and cognitive decline. On brain magnetic resonance imaging a predominant involvement of the corpus callosum, the corticospinal tracts and the cerebellum are noted. A storage disease phenotype is present in some diseases, underscoring both clinical and molecular overlaps to lysosomal storage diseases. This review provides an update on the clinical, imaging, and genetic spectrum of congenital disorders of autophagy and highlights the importance of this pathway for neurometabolism and childhood-onset neurological diseases.
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Affiliation(s)
- Julian Teinert
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Robert Behne
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Miriam Wimmer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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34
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Makowski SL, Kuna RS, Field SJ. Induction of membrane curvature by proteins involved in Golgi trafficking. Adv Biol Regul 2019; 75:100661. [PMID: 31668661 PMCID: PMC7056495 DOI: 10.1016/j.jbior.2019.100661] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022]
Abstract
The Golgi apparatus serves a key role in processing and sorting lipids and proteins for delivery to their final cellular destinations. Vesicle exit from the Golgi initiates with directional deformation of the lipid bilayer to produce a bulge. Several mechanisms have been described by which lipids and proteins can induce directional membrane curvature to promote vesicle budding. Here we review some of the mechanisms implicated in inducing membrane curvature at the Golgi to promote vesicular trafficking to various cellular destinations.
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Affiliation(s)
- Stefanie L Makowski
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ramya S Kuna
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Seth J Field
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA, 92093, USA.
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35
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VPS53 gene is associated with a new phenotype of complicated hereditary spastic paraparesis. Neurogenetics 2019; 20:187-195. [DOI: 10.1007/s10048-019-00586-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/08/2019] [Indexed: 11/26/2022]
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36
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Cargo Sorting at the trans-Golgi Network for Shunting into Specific Transport Routes: Role of Arf Small G Proteins and Adaptor Complexes. Cells 2019; 8:cells8060531. [PMID: 31163688 PMCID: PMC6627992 DOI: 10.3390/cells8060531] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 01/27/2023] Open
Abstract
The trans-Golgi network (TGN) is responsible for selectively recruiting newly synthesized cargo into transport carriers for delivery to their appropriate destination. In addition, the TGN is responsible for receiving and recycling cargo from endosomes. The membrane organization of the TGN facilitates the sorting of cargoes into distinct populations of transport vesicles. There have been significant advances in defining the molecular mechanism involved in the recognition of membrane cargoes for recruitment into different populations of transport carriers. This machinery includes cargo adaptors of the adaptor protein (AP) complex family, and monomeric Golgi-localized γ ear-containing Arf-binding protein (GGA) family, small G proteins, coat proteins, as well as accessory factors to promote budding and fission of transport vesicles. Here, we review this literature with a particular focus on the transport pathway(s) mediated by the individual cargo adaptors and the cargo motifs recognized by these adaptors. Defects in these cargo adaptors lead to a wide variety of diseases.
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37
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Lobo-Alves SC, de Oliveira LA, Petzl-Erler ML. Region 1p13.2 including the RSBN1, PTPN22, AP4B1 and long non-coding RNA genes does not bear risk factors for endemic pemphigus foliaceus (fogo selvagem). Int J Immunogenet 2019; 46:139-145. [PMID: 30884100 DOI: 10.1111/iji.12423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 01/30/2019] [Accepted: 02/18/2019] [Indexed: 12/27/2022]
Abstract
Pemphigus foliaceus (PF) is an autoimmune skin disease characterized by autoantibodies directed mainly against desmoglein-1. The purpose of this study was to determine whether differential susceptibility to endemic PF in Brazil (fogo selvagem) is associated with polymorphisms at the cytogenetic location 1p13.2. Four single nucleotide polymorphisms that together tag 28 SNPs on a segment of approximately 312,000 bp encompassing the protein-coding genes MAGI3, PHTF1, RSBN1, PTPN22, BCL2L15, AP4B1, DCLRE1B, the pseudogenes MTND5P20, RPS2P14 (AL133517.1) and the long non-coding RNA genes AL137856.1, and AP4B1-AS1 were used as markers for association analysis in a case-control study. Allele, genotype and haplotype frequencies of rs33996649, rs2476601, rs3789604 and rs3195954 were compared between patient and control samples. No significant association was found. Lack of association with rs2476601 of the PTPN22 gene agrees with previous results for pemphigus vulgaris and the Tunisian form of endemic pemphigus foliaceus. The other three SNPs had never been analysed before in any form of pemphigus. We conclude that variants in structural and regulatory sites of region 1p13.2 are not susceptibility factors for fogo selvagem. We suggest careful investigation of this genomic region in diseases that had been previously associated with PTPN22, since there are several other genes relevant for immune-mediated diseases located in 1p13.2.
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Affiliation(s)
- Sara Cristina Lobo-Alves
- Laboratório de Genética Molecular Humana, Departamento de Genética, Universidade Federal do Paraná, Curitiba, Brazil
| | - Liana Alves de Oliveira
- Laboratório de Genética Molecular Humana, Departamento de Genética, Universidade Federal do Paraná, Curitiba, Brazil
| | - Maria Luiza Petzl-Erler
- Laboratório de Genética Molecular Humana, Departamento de Genética, Universidade Federal do Paraná, Curitiba, Brazil
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38
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Denton K, Mou Y, Xu CC, Shah D, Chang J, Blackstone C, Li XJ. Impaired mitochondrial dynamics underlie axonal defects in hereditary spastic paraplegias. Hum Mol Genet 2019; 27:2517-2530. [PMID: 29726929 DOI: 10.1093/hmg/ddy156] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/25/2018] [Indexed: 01/01/2023] Open
Abstract
Mechanisms by which long corticospinal axons degenerate in hereditary spastic paraplegia (HSP) are largely unknown. Here, we have generated induced pluripotent stem cells (iPSCs) from patients with two autosomal recessive forms of HSP, SPG15 and SPG48, which are caused by mutations in the ZFYVE26 and AP5Z1 genes encoding proteins in the same complex, the spastizin and AP5Z1 proteins, respectively. In patient iPSC-derived telencephalic glutamatergic and midbrain dopaminergic neurons, neurite number, length and branching are significantly reduced, recapitulating disease-specific phenotypes. We analyzed mitochondrial morphology and noted a significant reduction in both mitochondrial length and their densities within axons of these HSP neurons. Mitochondrial membrane potential was also decreased, confirming functional mitochondrial defects. Notably, mdivi-1, an inhibitor of the mitochondrial fission GTPase DRP1, rescues mitochondrial morphology defects and suppresses the impairment in neurite outgrowth and late-onset apoptosis in HSP neurons. Furthermore, knockdown of these HSP genes causes similar axonal defects, also mitigated by treatment with mdivi-1. Finally, neurite outgrowth defects in SPG15 and SPG48 cortical neurons can be rescued by knocking down DRP1 directly. Thus, abnormal mitochondrial morphology caused by an imbalance of mitochondrial fission and fusion underlies specific axonal defects and serves as a potential therapeutic target for SPG15 and SPG48.
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Affiliation(s)
- Kyle Denton
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Chong-Chong Xu
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Dhruvi Shah
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Jaerak Chang
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.,Departments of Biomedical Science, Brain Science, and Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
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39
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Seaman MNJ. Back From the Brink: Retrieval of Membrane Proteins From Terminal Compartments: Unexpected Pathways for Membrane Protein Retrieval From Vacuoles and Endolysosomes. Bioessays 2019; 41:e1800146. [PMID: 30706963 DOI: 10.1002/bies.201800146] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/03/2018] [Indexed: 11/12/2022]
Abstract
It has long been believed that membrane proteins present in degradative compartments such as endolysosomes or vacuoles would be destined for destruction. Now however, it appears that mechanisms and machinery exist in simple eukaryotes such as yeast and more complex organisms such as mammals that can rescue potentially "doomed" membrane proteins by retrieving them from these "late" compartments and recycling them back to the Golgi complex. In yeast, a sorting nexin dimer containing Snx4p can recognize and retrieve the Atg27p membrane protein while in mammals, the AP5 complex (with SPG11 and SPG15) directs the recycling of Golgi-localized proteins along with the cation-independent mannose 6-phosphate receptor (CIMPR). Although the respective machinery is different, there is much commonality between yeast and mammals regarding the mechanisms of retrieval and the physiological importance of these late recycling pathways.
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Affiliation(s)
- Matthew N J Seaman
- University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrookes Hospital, CB2 0XY, UK
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40
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Davies AK, Itzhak DN, Edgar JR, Archuleta TL, Hirst J, Jackson LP, Robinson MS, Borner GHH. AP-4 vesicles contribute to spatial control of autophagy via RUSC-dependent peripheral delivery of ATG9A. Nat Commun 2018; 9:3958. [PMID: 30262884 PMCID: PMC6160451 DOI: 10.1038/s41467-018-06172-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 08/17/2018] [Indexed: 12/03/2022] Open
Abstract
Adaptor protein 4 (AP-4) is an ancient membrane trafficking complex, whose function has largely remained elusive. In humans, AP-4 deficiency causes a severe neurological disorder of unknown aetiology. We apply unbiased proteomic methods, including 'Dynamic Organellar Maps', to find proteins whose subcellular localisation depends on AP-4. We identify three transmembrane cargo proteins, ATG9A, SERINC1 and SERINC3, and two AP-4 accessory proteins, RUSC1 and RUSC2. We demonstrate that AP-4 deficiency causes missorting of ATG9A in diverse cell types, including patient-derived cells, as well as dysregulation of autophagy. RUSC2 facilitates the transport of AP-4-derived, ATG9A-positive vesicles from the trans-Golgi network to the cell periphery. These vesicles cluster in close association with autophagosomes, suggesting they are the "ATG9A reservoir" required for autophagosome biogenesis. Our study uncovers ATG9A trafficking as a ubiquitous function of the AP-4 pathway. Furthermore, it provides a potential molecular pathomechanism of AP-4 deficiency, through dysregulated spatial control of autophagy.
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Affiliation(s)
- Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Daniel N Itzhak
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Tara L Archuleta
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany.
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41
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Altered distribution of ATG9A and accumulation of axonal aggregates in neurons from a mouse model of AP-4 deficiency syndrome. PLoS Genet 2018; 14:e1007363. [PMID: 29698489 PMCID: PMC5940238 DOI: 10.1371/journal.pgen.1007363] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/08/2018] [Accepted: 04/12/2018] [Indexed: 12/22/2022] Open
Abstract
The hereditary spastic paraplegias (HSP) are a clinically and genetically heterogeneous group of disorders characterized by progressive lower limb spasticity. Mutations in subunits of the heterotetrameric (ε-β4-μ4-σ4) adaptor protein 4 (AP-4) complex cause an autosomal recessive form of complicated HSP referred to as "AP-4 deficiency syndrome". In addition to lower limb spasticity, this syndrome features intellectual disability, microcephaly, seizures, thin corpus callosum and upper limb spasticity. The pathogenetic mechanism, however, remains poorly understood. Here we report the characterization of a knockout (KO) mouse for the AP4E1 gene encoding the ε subunit of AP-4. We find that AP-4 ε KO mice exhibit a range of neurological phenotypes, including hindlimb clasping, decreased motor coordination and weak grip strength. In addition, AP-4 ε KO mice display a thin corpus callosum and axonal swellings in various areas of the brain and spinal cord. Immunohistochemical analyses show that the transmembrane autophagy-related protein 9A (ATG9A) is more concentrated in the trans-Golgi network (TGN) and depleted from the peripheral cytoplasm both in skin fibroblasts from patients with mutations in the μ4 subunit of AP-4 and in various neuronal types in AP-4 ε KO mice. ATG9A mislocalization is associated with increased tendency to accumulate mutant huntingtin (HTT) aggregates in the axons of AP-4 ε KO neurons. These findings indicate that the AP-4 ε KO mouse is a suitable animal model for AP-4 deficiency syndrome, and that defective mobilization of ATG9A from the TGN and impaired autophagic degradation of protein aggregates might contribute to neuroaxonal dystrophy in this disorder.
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42
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Toth AE, Siupka P, P Augustine TJ, Venø ST, Thomsen LB, Moos T, Lohi HT, Madsen P, Lykke-Hartmann K, Nielsen MS. The Endo-Lysosomal System of Brain Endothelial Cells Is Influenced by Astrocytes In Vitro. Mol Neurobiol 2018; 55:8522-8537. [PMID: 29560581 DOI: 10.1007/s12035-018-0988-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/05/2018] [Indexed: 12/28/2022]
Abstract
Receptor- and adsorptive-mediated transport through brain endothelial cells (BEC) of the blood-brain barrier (BBB) involves a complex array of subcellular vesicular structures, the endo-lysosomal system. It consists of several types of vesicles, such as early, recycling, and late endosomes, retromer-positive structures, and lysosomes. Since this system is important for receptor-mediated transcytosis of drugs across brain capillaries, our aim was to characterise the endo-lysosomal system in BEC with emphasis on their interactions with astrocytes. We used primary porcine BEC in monoculture and in co-culture with primary rat astrocytes. The presence of astrocytes changed the intraendothelial vesicular network and significantly impacted vesicular number, morphology, and distribution. Additionally, gene set enrichment analysis revealed that 60 genes associated with vesicular trafficking showed altered expression in co-cultured BEC. Cytosolic proteins involved in subcellular trafficking were investigated to mark transport routes, such as RAB25 for transcytosis. Strikingly, the adaptor protein called AP1-μ1B, important for basolateral sorting in epithelial cells, was not expressed in BEC. Altogether, our data pin-point unique features of BEC trafficking network, essentially mapping the endo-lysosomal system of in vitro BBB models. Consequently, our findings constitute a valuable basis for planning the optimal route across the BBB when advancing drug delivery to the brain.
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Affiliation(s)
- Andrea E Toth
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Piotr Siupka
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Thomas J P Augustine
- Research Program for Molecular Neurology, Helsinki University, Haartmaninkatu 8, 00290, Helsinki, Finland
| | - Susanne T Venø
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark
| | - Louiza B Thomsen
- Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.,Laboratory of Neurobiology, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3, 9220, Aalborg, Denmark
| | - Torben Moos
- Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.,Laboratory of Neurobiology, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3, 9220, Aalborg, Denmark
| | - Hannes T Lohi
- Research Program for Molecular Neurology, Helsinki University, Haartmaninkatu 8, 00290, Helsinki, Finland
| | - Peder Madsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark.,Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgårdsvej 21, 8200, Aarhus, Denmark.,Department of Clinical Medicine, Faculty of Health, Aarhus University, Bartholins Alle 6, 8000, Aarhus, Denmark
| | - Morten S Nielsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark. .,Lundbeck Foundation, Research Initiative on Brain Barriers and Drug Delivery, Scherfigsvej 7, 2100, Copenhagen, Denmark.
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43
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Guardia CM, De Pace R, Mattera R, Bonifacino JS. Neuronal functions of adaptor complexes involved in protein sorting. Curr Opin Neurobiol 2018; 51:103-110. [PMID: 29558740 DOI: 10.1016/j.conb.2018.02.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 11/30/2022]
Abstract
Selective transport of transmembrane proteins to different intracellular compartments often involves the recognition of sorting signals in the cytosolic domains of the proteins by components of membrane coats. Some of these coats have as their key components a family of heterotetrameric adaptor protein (AP) complexes named AP-1 through AP-5. AP complexes play important roles in all cells, but their functions are most critical in neurons because of the extreme compartmental complexity of these cells. Accordingly, various diseases caused by mutations in AP subunit genes exhibit a range of neurological abnormalities as their most salient features. In this article, we discuss the properties of the different AP complexes, with a focus on their roles in neuronal physiology and pathology.
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Affiliation(s)
- Carlos M Guardia
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Raffaella De Pace
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rafael Mattera
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Accogli A, Hamdan FF, Poulin C, Nassif C, Rouleau GA, Michaud JL, Srour M. A novel homozygous AP4B1 mutation in two brothers with AP-4 deficiency syndrome and ocular anomalies. Am J Med Genet A 2018; 176:985-991. [PMID: 29430868 DOI: 10.1002/ajmg.a.38628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 01/14/2018] [Accepted: 01/16/2018] [Indexed: 01/09/2023]
Abstract
Adaptor protein complex-4 (AP-4) is a heterotetrameric protein complex which plays a key role in vesicle trafficking in neurons. Mutations in genes affecting different subunits of AP-4, including AP4B1, AP4E1, AP4S1, and AP4M1, have been recently associated with an autosomal recessive phenotype, consisting of spastic tetraplegia, and intellectual disability (ID). The overlapping clinical picture among individuals carrying mutations in any of these genes has prompted the terms "AP-4 deficiency syndrome" for this clinically recognizable phenotype. Using whole-exome sequencing, we identified a novel homozygous mutation (c.991C>T, p.Q331*, NM_006594.4) in AP4B1 in two siblings from a consanguineous Pakistani couple, who presented with severe ID, progressive spastic tetraplegia, epilepsy, and microcephaly. Sanger sequencing confirmed the mutation was homozygous in the siblings and heterozygous in the parents. Similar to previously reported individuals with AP4B1 mutations, brain MRI revealed ventriculomegaly and white matter loss. Interestingly, in addition to the typical facial gestalt reported in other AP-4 deficiency cases, the older brother presented with congenital left Horner syndrome, bilateral optic nerve atrophy and cataract, which have not been previously reported in this condition. In summary, we report a novel AP4B1 homozygous mutation in two siblings and review the phenotype of AP-4 deficiency, speculating on a possible role of AP-4 complex in eye development.
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Affiliation(s)
- Andrea Accogli
- Department of Pediatrics, McGill University, Montreal, Canada.,Istituto Giannina Gaslini, Genova, Italy
| | - Fadi F Hamdan
- CHU Sainte-Justine Research Center, Montréal, Canada
| | - Chantal Poulin
- Department of Pediatrics, McGill University, Montreal, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | | | - Guy A Rouleau
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Jacques L Michaud
- CHU Sainte-Justine Research Center, Montréal, Canada.,Departments of Pediatrics and Neurosciences, Université de Montréal, Montreal, Canada
| | - Myriam Srour
- Department of Pediatrics, McGill University, Montreal, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
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Role of the AP-5 adaptor protein complex in late endosome-to-Golgi retrieval. PLoS Biol 2018; 16:e2004411. [PMID: 29381698 PMCID: PMC5806898 DOI: 10.1371/journal.pbio.2004411] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/09/2018] [Accepted: 01/12/2018] [Indexed: 01/17/2023] Open
Abstract
The AP-5 adaptor protein complex is presumed to function in membrane traffic, but so far nothing is known about its pathway or its cargo. We have used CRISPR-Cas9 to knock out the AP-5 ζ subunit gene, AP5Z1, in HeLa cells, and then analysed the phenotype by subcellular fractionation profiling and quantitative mass spectrometry. The retromer complex had an altered steady-state distribution in the knockout cells, and several Golgi proteins, including GOLIM4 and GOLM1, were depleted from vesicle-enriched fractions. Immunolocalisation showed that loss of AP-5 led to impaired retrieval of the cation-independent mannose 6-phosphate receptor (CIMPR), GOLIM4, and GOLM1 from endosomes back to the Golgi region. Knocking down the retromer complex exacerbated this phenotype. Both the CIMPR and sortilin interacted with the AP-5–associated protein SPG15 in pull-down assays, and we propose that sortilin may act as a link between Golgi proteins and the AP-5/SPG11/SPG15 complex. Together, our findings suggest that AP-5 functions in a novel sorting step out of late endosomes, acting as a backup pathway for retromer. This provides a mechanistic explanation for why mutations in AP-5/SPG11/SPG15 cause cells to accumulate aberrant endolysosomes, and highlights the role of endosome/lysosome dysfunction in the pathology of hereditary spastic paraplegia and other neurodegenerative disorders. Eukaryotic cells contain multiple membrane-bound compartments, each with a distinct function and molecular composition. Proteins are transported from one compartment to another by vesicular carriers. Formation of these carriers requires coat proteins, which both shape the membrane into a vesicle and select the proteins that are to be included as cargo. In many cases, cargo selection is facilitated by an adaptor protein (AP) complex, of which 5 have been identified. The most recently identified complex, AP-5, localises to a late endosomal/lysosomal compartment, and patients with mutations in AP-5 have a form of hereditary spastic paraplegia characterised by aberrant lysosomes. However, the precise function of AP-5, including its cargo and its pathway, has until now been unclear. In the present study, we have used unbiased subcellular proteomics to look for changes in the localisation of thousands of different proteins in cells from which AP-5 has been deleted by gene editing. We found that there are defects in the retrieval of several proteins from late endosomes back to the Golgi apparatus. Thus, we propose that AP-5 facilitates a novel late-acting retrieval pathway, which contributes to normal lysosomal homeostasis.
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Ebrahimi-Fakhari D, Cheng C, Dies K, Diplock A, Pier DB, Ryan CS, Lanpher BC, Hirst J, Chung WK, Sahin M, Rosser E, Darras B, Bennett JT. Clinical and genetic characterization of AP4B1-associated SPG47. Am J Med Genet A 2017; 176:311-318. [PMID: 29193663 DOI: 10.1002/ajmg.a.38561] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/05/2017] [Accepted: 11/07/2017] [Indexed: 11/12/2022]
Abstract
The hereditary spastic paraplegias (HSPs) are a heterogeneous group of disorders characterized by degeneration of the corticospinal and spinocerebellar tracts leading to progressive spasticity. One subtype, spastic paraplegia type 47 (SPG47 or HSP-AP4B1), is due to bi-allelic loss-of-function mutations in the AP4B1 gene. AP4B1 is a subunit of the adapter protein complex 4 (AP-4), a heterotetrameric protein complex that regulates the transport of membrane proteins. Since 2011, 11 individuals from six families with AP4B1 mutations have been reported, nine of whom had homozygous mutations and were from consanguineous families. Here we report eight patients with AP4B1-associated SPG47, the majority born to non-consanguineous parents and carrying compound heterozygous mutations. Core clinical features in this cohort and previously published patients include neonatal hypotonia that progresses to spasticity, early onset developmental delay with prominent motor delay and severely impaired or absent speech development, episodes of stereotypic laughter, seizures including frequent febrile seizures, thinning of the corpus callosum, and delayed myelination/white matter loss. Given that some of the features of AP-4 deficiency overlap with those of cerebral palsy, and the discovery of the disorder in non-consanguineous populations, we believe that AP-4 deficiency may be more common than previously appreciated.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.,Division of General Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Chi Cheng
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Kira Dies
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amelia Diplock
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Danielle B Pier
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.,Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts
| | - Conor S Ryan
- Department of Child and Adolescent Neurology, Mayo Clinic, Rochester, Minnesota
| | | | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Wendy K Chung
- Department of Pediatrics and Medicine, Columbia University Medical Center, New York, New York
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elisabeth Rosser
- Department of Clinical Genetics, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Basil Darras
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - James T Bennett
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, and Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington
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Archuleta TL, Frazier MN, Monken AE, Kendall AK, Harp J, McCoy AJ, Creanza N, Jackson LP. Structure and evolution of ENTH and VHS/ENTH-like domains in tepsin. Traffic 2017; 18:590-603. [PMID: 28691777 PMCID: PMC5567745 DOI: 10.1111/tra.12499] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/02/2017] [Accepted: 07/06/2017] [Indexed: 12/28/2022]
Abstract
Tepsin is currently the only accessory trafficking protein identified in adaptor-related protein 4 (AP4)-coated vesicles originating at the trans-Golgi network (TGN). The molecular basis for interactions between AP4 subunits and motifs in the tepsin C-terminus have been characterized, but the biological role of tepsin remains unknown. We determined X-ray crystal structures of the tepsin epsin N-terminal homology (ENTH) and VHS/ENTH-like domains. Our data reveal unexpected structural features that suggest key functional differences between these and similar domains in other trafficking proteins. The tepsin ENTH domain lacks helix0, helix8 and a lipid binding pocket found in epsin1/2/3. These results explain why tepsin requires AP4 for its membrane recruitment and further suggest ENTH domains cannot be defined solely as lipid binding modules. The VHS domain lacks helix8 and thus contains fewer helices than other VHS domains. Structural data explain biochemical and biophysical evidence that tepsin VHS does not mediate known VHS functions, including recognition of dileucine-based cargo motifs or ubiquitin. Structural comparisons indicate the domains are very similar to each other, and phylogenetic analysis reveals their evolutionary pattern within the domain superfamily. Phylogenetics and comparative genomics further show tepsin within a monophyletic clade that diverged away from epsins early in evolutionary history (~1500 million years ago). Together, these data provide the first detailed molecular view of tepsin and suggest tepsin structure and function diverged away from other epsins. More broadly, these data highlight the challenges inherent in classifying and understanding protein function based only on sequence and structure.
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Affiliation(s)
- Tara L. Archuleta
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
| | - Meredith N. Frazier
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
| | - Anderson E. Monken
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
| | - Amy K. Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
| | - Joel Harp
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
| | - Airlie J. McCoy
- Cambridge Institute for Medical Research, Department of Clinical
Biochemistry, University of Cambridge, Hills Road, Cambridge, United Kingdom
| | - Nicole Creanza
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
| | - Lauren P. Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville,
TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN,
USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN,
USA
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Martzoukou O, Amillis S, Zervakou A, Christoforidis S, Diallinas G. The AP-2 complex has a specialized clathrin-independent role in apical endocytosis and polar growth in fungi. eLife 2017; 6. [PMID: 28220754 PMCID: PMC5338921 DOI: 10.7554/elife.20083] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 02/07/2017] [Indexed: 12/26/2022] Open
Abstract
Filamentous fungi provide excellent systems for investigating the role of the AP-2 complex in polar growth. Using Aspergillus nidulans, we show that AP-2 has a clathrin-independent essential role in polarity maintenance and growth. This is in line with a sequence analysis showing that the AP-2 β subunit (β2) of higher fungi lacks a clathrin-binding domain, and experiments showing that AP-2 does not co-localize with clathrin. We provide genetic and cellular evidence that AP-2 interacts with endocytic markers SlaBEnd4 and SagAEnd3 and the lipid flippases DnfA and DnfB in the sub-apical collar region of hyphae. The role of AP-2 in the maintenance of proper apical membrane lipid and cell wall composition is further supported by its functional interaction with BasA (sphingolipid biosynthesis) and StoA (apical sterol-rich membrane domains), and its essentiality in polar deposition of chitin. Our findings support that the AP-2 complex of dikarya has acquired, in the course of evolution, a specialized clathrin-independent function necessary for fungal polar growth. DOI:http://dx.doi.org/10.7554/eLife.20083.001
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Affiliation(s)
- Olga Martzoukou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Amalia Zervakou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Savvas Christoforidis
- Institute of Molecular Biology and Biotechnology-Biomedical Research, Foundation for Research and Technology, Ioannina, Greece.,Laboratory of Biological Chemistry, Department of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
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Subcellular Trafficking of Mammalian Lysosomal Proteins: An Extended View. Int J Mol Sci 2016; 18:ijms18010047. [PMID: 28036022 PMCID: PMC5297682 DOI: 10.3390/ijms18010047] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/15/2016] [Accepted: 12/18/2016] [Indexed: 01/02/2023] Open
Abstract
Lysosomes clear macromolecules, maintain nutrient and cholesterol homeostasis, participate in tissue repair, and in many other cellular functions. To assume these tasks, lysosomes rely on their large arsenal of acid hydrolases, transmembrane proteins and membrane-associated proteins. It is therefore imperative that, post-synthesis, these proteins are specifically recognized as lysosomal components and are correctly sorted to this organelle through the endosomes. Lysosomal transmembrane proteins contain consensus motifs in their cytosolic regions (tyrosine- or dileucine-based) that serve as sorting signals to the endosomes, whereas most lysosomal acid hydrolases acquire mannose 6-phosphate (Man-6-P) moieties that mediate binding to two membrane receptors with endosomal sorting motifs in their cytosolic tails. These tyrosine- and dileucine-based motifs are tickets for boarding in clathrin-coated carriers that transport their cargo from the trans-Golgi network and plasma membrane to the endosomes. However, increasing evidence points to additional mechanisms participating in the biogenesis of lysosomes. In some cell types, for example, there are alternatives to the Man-6-P receptors for the transport of some acid hydrolases. In addition, several “non-consensus” sorting motifs have been identified, and atypical transport routes to endolysosomes have been brought to light. These “unconventional” or “less known” transport mechanisms are the focus of this review.
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50
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Traffic Through the Trans-Golgi Network and the Endosomal System Requires Collaboration Between Exomer and Clathrin Adaptors in Fission Yeast. Genetics 2016; 205:673-690. [PMID: 27974503 DOI: 10.1534/genetics.116.193458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 12/09/2016] [Indexed: 11/18/2022] Open
Abstract
Despite its biological and medical relevance, traffic from the Golgi to the plasma membrane (PM) is one of the least understood steps of secretion. Exomer is a protein complex that mediates the trafficking of certain cargoes from the trans-Golgi network/early endosomes to the PM in budding yeast. Here, we show that in Schizosaccharomyces pombe the Cfr1 and Bch1 proteins constitute the simplest form of an exomer. Cfr1 co-immunoprecipitates with Assembly Polypeptide adaptor 1 (AP-1), AP-2, and Golgi-localized, gamma-adaptin ear domain homology, ARF-binding (GGA) subunits, and cfr1+ interacts genetically with AP-1 and GGA genes. Exomer-defective cells exhibit multiple mild defects, including alterations in the morphology of Golgi stacks and the distribution of the synaptobrevin-like Syb1 protein, carboxypeptidase missorting, and stress sensitivity. S. pombe apm1Δ cells exhibit a defect in trafficking through the early endosomes that is severely aggravated in the absence of exomer. apm1Δ cfr1Δ cells exhibit a dramatic disorganization of intracellular compartments, including massive accumulation of electron-dense tubulovesicular structures. While the trans-Golgi network/early endosomes are severely disorganized in the apm1Δ cfr1Δ strain, gga21Δ gga22Δ cfr1Δ cells exhibit a significant disturbance of the prevacuolar/vacuolar compartments. Our findings show that exomer collaborates with clathrin adaptors in trafficking through diverse cellular compartments, and that this collaboration is important to maintain their integrity. These results indicate that the effect of eliminating exomer is more pervasive than that described to date, and suggest that exomer complexes might participate in diverse steps of vesicle transport in other organisms.
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