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Yamada Y, Schaap P. The proppin Bcas3 and its interactor KinkyA localize to the early phagophore and regulate autophagy. Autophagy 2021; 17:640-655. [PMID: 32116088 PMCID: PMC8032249 DOI: 10.1080/15548627.2020.1725403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/23/2020] [Accepted: 01/29/2020] [Indexed: 11/11/2022] Open
Abstract
To resolve the signaling mechanisms that mediate the starvation-induced processes of Dictyostelium sporulation and encystation, we performed insertional mutagenesis on cells harboring an mRFP-tagged spore gene. We isolated a mutant in kinkyA (knkA), a gene without known function, which formed fruiting bodies with a kinked stalk and lacking viable spores. Immunoprecipitation of lysates of KnkA-YFP-transformed knkA- cells yielded a mammalian BCAS3 homolog as a KnkA interactor. bcas3- phenocopied knkA- and Bcas3 colocalized with KnkA to puncta. Bcas3 shares sequence similarity with proppins (beta-propellors that bind phosphoinositides). Mutation of 2 Bcas3 residues that are essential for PtdIns3P binding in proppins prevented Bcas3 binding to PtdIns3P as well as punctate Bcas3 and KnkA localization. KnkA puncta also colocalized with small but not large vesicles that contain the autophagy protein Atg8 and were contiguous with the endoplasmic reticulum. knkA- and bcas3- cells showed a pronounced decrease of RFP-GFP-Atg8 in neutral early autophagosomes, indicating that KnkA and Bcas3 are required for macroautophagy/autophagy. Knockouts in atg7, atg5 or atg9 substantiated this finding by showing similar sporulation defects as knkA- and bcas3-. Defective Dictyostelium sporulation is evidently a useful diagnostic tool for the discovery of novel autophagy genes.Abbreviations: Atg: Autophagy-related; BCAS3: BCAS3 microtubule associated cell migration factor; cAMP: 3',5'-cyclic adenosine monophosphate; ER: endoplasmic reticulum; GFP: green fluorescent protein; PAS: phagophore assembly site; PRKA/PKA: protein kinase cAMP-dependent; Proppin: beta-propellers that bind phosphoinositides; PtdIns3P: phosphatidylinositol 3-phosphate; REMI: restriction enzyme-mediated insertional mutagenesis; RFP: red fluorescent protein; RT-qPCR: reverse transcriptase - quantitative polymerase chain reaction; WIPI: WD repeat domain, phosphoinositide interacting; YFP: yellow fluorescent protein.
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Affiliation(s)
- Yoko Yamada
- School of Life Sciences, University of Dundee, Dundee, UK
- Department of Biology, Faculty of Science, Toho University, Funabashi, Japan
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee, UK
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2
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Muñoz-Braceras S, Tornero-Écija AR, Vincent O, Escalante R. VPS13A is closely associated with mitochondria and is required for efficient lysosomal degradation. Dis Model Mech 2019; 12:dmm036681. [PMID: 30709847 PMCID: PMC6398486 DOI: 10.1242/dmm.036681] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/22/2019] [Indexed: 12/11/2022] Open
Abstract
Members of the VPS13 family are associated with various human diseases. In particular, the loss of function of VPS13A leads to chorea-acanthocytosis (ChAc), a rare neurodegenerative disease without available curative treatments. Autophagy has been considered a promising therapeutic target because the absence of VPS13A causes a defective autophagy flux. However, the mechanistic details of this deficiency are unknown. Here, we identified Rab7A as an interactor of one of the VPS13 family members in Dictyostelium discoideum and showed that this interaction is conserved between the human homologs VPS13A and RAB7A in HeLa cells. As RAB7A is a key player in endosome trafficking, we addressed the possible function of VPS13A in endosome dynamics and lysosome degradation. Our results suggest that the decrease in autophagy observed in the absence of VPS13A may be the result of a more general defect in endocytic trafficking and lysosomal degradation. Unexpectedly, we found that VPS13A is closely localized to mitochondria, suggesting that the role of VPS13A in the endolysosomal pathway might be related to inter-organelle communication. We show that VPS13A localizes at the interface between mitochondria-endosomes and mitochondria-endoplasmic reticulum and that the presence of membrane contact sites is altered in the absence of VPS13A. Based on these findings, we propose that therapeutic strategies aimed at modulating the endolysosomal pathway could be beneficial in the treatment of ChAc.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sandra Muñoz-Braceras
- Instituto de Investigaciones Biomédicas Alberto Sols, Department of Experimental Models of Human Diseases, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma Madrid (UAM), 28029-Madrid, Spain
| | - Alba R Tornero-Écija
- Instituto de Investigaciones Biomédicas Alberto Sols, Department of Experimental Models of Human Diseases, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma Madrid (UAM), 28029-Madrid, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Alberto Sols, Department of Experimental Models of Human Diseases, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma Madrid (UAM), 28029-Madrid, Spain
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Alberto Sols, Department of Experimental Models of Human Diseases, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma Madrid (UAM), 28029-Madrid, Spain
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3
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Xiong Q, Li W, Li P, Yang M, Wu C, Eichinger L. The Role of ATG16 in Autophagy and The Ubiquitin Proteasome System. Cells 2018; 8:cells8010002. [PMID: 30577509 PMCID: PMC6356889 DOI: 10.3390/cells8010002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023] Open
Abstract
Autophagy and the ubiquitin proteasome system (UPS) are the two major cellular degradation pathways, which are critical for the maintenance of cell homeostasis. The two pathways differ in their mechanisms and clients. The evolutionary conserved ATG16 plays a key role in autophagy and appears to link autophagy with the UPS. Here, we review the role of ATG16 in different species. We summarize the current knowledge of its functions in autophagosome membrane expansion and autophagosome formation, in Crohn’s disease, and in bacterial sequestration. In addition, we provide information on its autophagy-independent functions and its role in the crosstalk between autophagy and the UPS.
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Affiliation(s)
- Qiuhong Xiong
- Institute of Biomedical Sciences, Shanxi University, No.92 Wucheng Road, Taiyuan 030006, China.
| | - Wenjing Li
- Institute of Biomedical Sciences, Shanxi University, No.92 Wucheng Road, Taiyuan 030006, China.
| | - Ping Li
- Institute of Biomedical Sciences, Shanxi University, No.92 Wucheng Road, Taiyuan 030006, China.
| | - Min Yang
- Institute of Biomedical Sciences, Shanxi University, No.92 Wucheng Road, Taiyuan 030006, China.
| | - Changxin Wu
- Institute of Biomedical Sciences, Shanxi University, No.92 Wucheng Road, Taiyuan 030006, China.
| | - Ludwig Eichinger
- Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany.
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4
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Peikert K, Danek A, Hermann A. Current state of knowledge in Chorea-Acanthocytosis as core Neuroacanthocytosis syndrome. Eur J Med Genet 2018; 61:699-705. [DOI: 10.1016/j.ejmg.2017.12.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 12/01/2017] [Accepted: 12/14/2017] [Indexed: 11/30/2022]
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5
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Mesquita A, Cardenal-Muñoz E, Dominguez E, Muñoz-Braceras S, Nuñez-Corcuera B, Phillips BA, Tábara LC, Xiong Q, Coria R, Eichinger L, Golstein P, King JS, Soldati T, Vincent O, Escalante R. Autophagy in Dictyostelium: Mechanisms, regulation and disease in a simple biomedical model. Autophagy 2016; 13:24-40. [PMID: 27715405 DOI: 10.1080/15548627.2016.1226737] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Autophagy is a fast-moving field with an enormous impact on human health and disease. Understanding the complexity of the mechanism and regulation of this process often benefits from the use of simple experimental models such as the social amoeba Dictyostelium discoideum. Since the publication of the first review describing the potential of D. discoideum in autophagy, significant advances have been made that demonstrate both the experimental advantages and interest in using this model. Since our previous review, research in D. discoideum has shed light on the mechanisms that regulate autophagosome formation and contributed significantly to the study of autophagy-related pathologies. Here, we review these advances, as well as the current techniques to monitor autophagy in D. discoideum. The comprehensive bioinformatics search of autophagic proteins that was a substantial part of the previous review has not been revisited here except for those aspects that challenged previous predictions such as the composition of the Atg1 complex. In recent years our understanding of, and ability to investigate, autophagy in D. discoideum has evolved significantly and will surely enable and accelerate future research using this model.
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Affiliation(s)
- Ana Mesquita
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain.,b University of Cincinnati College of Medicine , Cincinnati , OH , USA
| | - Elena Cardenal-Muñoz
- c Départment de Biochimie , Faculté des Sciences, Université de Genève , Switzerland
| | - Eunice Dominguez
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain.,d Departamento de Genética Molecular , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico City , México
| | - Sandra Muñoz-Braceras
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain
| | | | - Ben A Phillips
- e Department of Biomedical Sciences , University of Sheffield , UK
| | - Luis C Tábara
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain
| | - Qiuhong Xiong
- f Center for Biochemistry, Medical Faculty, University of Cologne , Cologne , Germany
| | - Roberto Coria
- d Departamento de Genética Molecular , Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , Mexico City , México
| | - Ludwig Eichinger
- f Center for Biochemistry, Medical Faculty, University of Cologne , Cologne , Germany
| | - Pierre Golstein
- g Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2 , Inserm, U1104, CNRS UMR7280, Marseille , France
| | - Jason S King
- e Department of Biomedical Sciences , University of Sheffield , UK
| | - Thierry Soldati
- c Départment de Biochimie , Faculté des Sciences, Université de Genève , Switzerland
| | - Olivier Vincent
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain
| | - Ricardo Escalante
- a Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM) , Madrid , Spain
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6
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Sasaki N, Nakamura M, Kodama A, Urata Y, Shiokawa N, Hayashi T, Sano A. Chorein interacts with α‐tubulin and histone deacetylase 6, and overexpression preserves cell viability during nutrient deprivation in human embryonic kidney 293 cells. FASEB J 2016; 30:3726-3732. [DOI: 10.1096/fj.201500191rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 07/18/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Natsuki Sasaki
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Masayuki Nakamura
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Akiko Kodama
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Yuka Urata
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Nari Shiokawa
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Takehiro Hayashi
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
| | - Akira Sano
- Department of PsychiatryKagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
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7
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Loomis WF. Genetic control of morphogenesis in Dictyostelium. Dev Biol 2015; 402:146-61. [PMID: 25872182 PMCID: PMC4464777 DOI: 10.1016/j.ydbio.2015.03.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/12/2015] [Accepted: 03/25/2015] [Indexed: 01/06/2023]
Abstract
Cells grow, move, expand, shrink and die in the process of generating the characteristic shapes of organisms. Although the structures generated during development of the social amoeba Dictyostelium discoideum look nothing like the structures seen in metazoan embryogenesis, some of the morphogenetic processes used in their making are surprisingly similar. Recent advances in understanding the molecular basis for directed cell migration, cell type specific sorting, differential adhesion, secretion of matrix components, pattern formation, regulation and terminal differentiation are reviewed. Genes involved in Dictyostelium aggregation, slug formation, and culmination of fruiting bodies are discussed.
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Affiliation(s)
- William F Loomis
- Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, United States.
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8
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Abnormal red cell features associated with hereditary neurodegenerative disorders: the neuroacanthocytosis syndromes. Curr Opin Hematol 2015; 21:201-9. [PMID: 24626044 DOI: 10.1097/moh.0000000000000035] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This review discusses the mechanisms involved in the generation of thorny red blood cells (RBCs), known as acanthocytes, in patients with neuroacanthocytosis, a heterogenous group of neurodegenerative hereditary disorders that include chorea-acanthocytosis (ChAc) and McLeod syndrome (MLS). RECENT FINDINGS Although molecular defects associated with neuroacanthocytosis have been identified recently, their pathophysiology and the related RBC abnormalities are largely unknown. Studies in ChAc RBCs have shown an altered association between the cytoskeleton and the integral membrane protein compartment in the absence of major changes in RBC membrane composition. In ChAc RBCs, abnormal Lyn kinase activation in a Syk-independent fashion has been reported recently, resulting in increased band 3 tyrosine phosphorylation and perturbation of the stability of the multiprotein band 3-based complexes bridging the membrane to the spectrin-based membrane skeleton. Similarly, in MLS, the absence of XK-protein, which is associated with the spectrin-actin-4.1 junctional complex, is associated with an abnormal membrane protein phosphorylation state, with destabilization of the membrane skeletal network resulting in generation of acanthocytes. SUMMARY A novel mechanism in generation of acanthocytes involving abnormal Lyn activation, identified in ChAc, expands the acanthocytosis phenomenon toward protein-protein interactions, controlled by phosphorylation-related abnormal signaling.
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9
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Shiokawa N, Nakamura M, Sameshima M, Deguchi A, Hayashi T, Sasaki N, Sano A. Chorein, the protein responsible for chorea-acanthocytosis, interacts with β-adducin and β-actin. Biochem Biophys Res Commun 2013; 441:96-101. [PMID: 24129186 DOI: 10.1016/j.bbrc.2013.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022]
Abstract
Chorea-acanthocytosis (ChAc) is an autosomal, recessive hereditary disease characterized by striatal neurodegeneration and acanthocytosis, and caused by loss of function mutations in the vacuolar protein sorting 13 homolog A (VPS13A) gene. VPS13A encodes chorein whose physiological function at the molecular level is poorly understood. In this study, we show that chorein interacts with β-adducin and β-actin. We first compare protein expression in human erythrocyte membranes using proteomic analysis. Protein levels of β-adducin isoform 1 and β-actin are markedly decreased in erythrocyte membranes from a ChAc patient. Subsequent co-immunoprecipitation (co-IP) and reverse co-IP assays using extracts from chorein-overexpressing human embryonic kidney 293 (HEK293) cells, shows that β-adducin (isoforms 1 and 2) and β-actin interact with chorein. Immunocytochemical analysis using chorein-overexpressing HEK293 cells demonstrates co-localization of chorein with β-adducin and β-actin. In addition, immunoreactivity of β-adducin isoform 1 is significantly decreased in the striatum of gene-targeted ChAc-model mice. Adducin and actin are membrane cytoskeletal proteins, involved in synaptic function. Expression of β-adducin is restricted to the brain and hematopoietic tissues, corresponding to the main pathological lesions of ChAc, and thereby implicating β-adducin and β-actin in ChAc pathogenesis.
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Affiliation(s)
- Nari Shiokawa
- Department of Psychiatry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
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10
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Zhang L, Wang S, Lin J. Clinical and molecular research of neuroacanthocytosis. Neural Regen Res 2013; 8:833-42. [PMID: 25206731 PMCID: PMC4146083 DOI: 10.3969/j.issn.1673-5374.2013.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 12/23/2012] [Indexed: 11/18/2022] Open
Abstract
Neuroacanthocytosis is an autosomal recessive or dominant inherited disease characterized by widespread, non-specific nervous system symptoms, or spiculated "acanthocytic" red blood cells. The clinical manifestations typically involve chorea and dystonia, or a range of other movement disorders. Psychiatric and cognitive symptoms may also be present. The two core neuroacanthocytosis syndromes, in which acanthocytosis is atypical, are autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome. Acanthocytes are found in a smaller proportion of patients with Huntington's disease-like 2 and pantothenate kinase-associated neurodegeneration. Because the clinical manifestations are diverse and complicated, in this review we present features of inheritance, age of onset, neuroimaging and laboratory findings, as well as the spectrum of central and peripheral neurological abnormalities and extraneuronal involvement to help distinguish the four specific syndromes.
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Affiliation(s)
- Lihong Zhang
- Department of Neurology, Dalian Municipal Central Hospital, Affiliated Hospital of Dalian Medical University, Dalian 116033, Liaoning Province, China
| | - Suping Wang
- Department of Neurology, Dalian Municipal Central Hospital, Affiliated Hospital of Dalian Medical University, Dalian 116033, Liaoning Province, China
| | - Jianwen Lin
- Department of Neurology, Dalian Municipal Central Hospital, Affiliated Hospital of Dalian Medical University, Dalian 116033, Liaoning Province, China
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Jaiswal P, Singh SP, Aiyar P, Akkali R, Baskar R. Regulation of multiple tip formation by caffeine in cellular slime molds. BMC DEVELOPMENTAL BIOLOGY 2012; 12:26. [PMID: 22928977 PMCID: PMC3488011 DOI: 10.1186/1471-213x-12-26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/20/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND The multicellular slug in Dictyostelium has a single tip that acts as an organising centre patterning the rest of the slug. High adenosine levels at the tip are believed to be responsible for this tip dominance and the adenosine antagonist, caffeine overrides this dominance promoting multiple tip formation. RESULTS Caffeine induced multiple tip effect is conserved in all the Dictyostelids tested. Two key components of cAMP relay namely, cAMP phosphodiesterase (Pde4) and adenyl cyclase-A (AcaA) levels get reduced during secondary tip formation in Dictyostelium discoideum. Pharmacological inhibition of cAMP phosphodiesterase also resulted in multiple tips. Caffeine reduces cAMP levels by 16.4, 2.34, 4.71 and 6.30 folds, respectively in D. discoideum, D. aureostipes, D. minutum and Polysphondylium pallidum. We propose that altered cAMP levels, perturbed cAMP gradient and impaired signalling may be the critical factors for the origin of multiple tips in other Dictyostelids as well. In the presence of caffeine, slug cell movement gets impaired and restricted. The cell type specific markers, ecmA (prestalk) and pspA (prespore) cells are not equally contributing during additional tip formation. During additional tip emergence, prespore cells transdifferentiate to compensate the loss of prestalk cells. CONCLUSION Caffeine decreases adenyl cyclase-A (AcaA) levels and as a consequence low cAMP is synthesised altering the gradient. Further if cAMP phosphodiesterase (Pde4) levels go down in the presence of caffeine, the cAMP gradient breaks down. When there is no cAMP gradient, directional movement is inhibited and might favour re-differentiation of prespore to prestalk cells.
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Affiliation(s)
- Pundrik Jaiswal
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Shashi Prakash Singh
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Prasad Aiyar
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Rakhil Akkali
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Ramamurthy Baskar
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
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Hayashi T, Kishida M, Nishizawa Y, Iijima M, Koriyama C, Nakamura M, Sano A, Kishida S. Subcellular localization and putative role of VPS13A/chorein in dopaminergic neuronal cells. Biochem Biophys Res Commun 2012; 419:511-6. [PMID: 22366033 DOI: 10.1016/j.bbrc.2012.02.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 02/07/2012] [Indexed: 11/18/2022]
Abstract
Chorea-acanthocytosis (ChAc) is a rare hereditary neurodegenerative disorder caused by loss of function mutations in the vacuolar protein sorting 13 homolog A (VPS13A) gene encoding chorein. Although a deficiency in chorein function leads to apoptosis of striatal neurons in ChAc model mouse, its detailed subcellular localization and physiological role remain unclear. In this study, we produced two anti-chorein polyclonal antibodies and examined the intracellular localization of endogenous chorein in neuronal cells. Immunocytochemically, chorein was observed in the termini of extended neurites and partially colocalized with synaptotagmin I in differentiated PC12 cells. Subcellular localization analysis by sucrose density gradient fractionation showed that chorein and synaptotagmin I were located in dense-core vesicles (DCVs), which contain dopamine. In addition, PC12 cells stably expressing carboxyterminal fragment of chorein increased K(+)-induced dopamine release. Taken together, these results suggest that chorein is involved in exocytosis of DCV.
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Affiliation(s)
- Takehiro Hayashi
- Department of Biochemistry and Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Japan
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13
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Vacuolar protein sorting protein 13A, TtVPS13A, localizes to the tetrahymena thermophila phagosome membrane and is required for efficient phagocytosis. EUKARYOTIC CELL 2011; 10:1207-18. [PMID: 21764909 DOI: 10.1128/ec.05089-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Vacuolar protein sorting 13 (VPS13) proteins have been studied in a number of organisms, and mutations in VPS13 genes have been implicated in two human genetic disorders, but the function of these proteins is poorly understood. The TtVPS13A protein was previously identified in a mass spectrometry analysis of the Tetrahymena thermophila phagosome proteome (M. E. Jacobs et al., Eukaryot. Cell 5:1990-2000, 2006), suggesting that it is involved in phagocytosis. In this study, we analyzed the structure of the macronuclear TtVPS13A gene, which was found to be composed of 17 exons spanning 12.5 kb and was predicted to encode a protein of 3,475 amino acids (aa). A strain expressing a TtVPS13A-green fluorescent protein (GFP) fusion protein was constructed, and the protein was found to associate with the phagosome membrane during the entire cycle of phagocytosis. In addition, Tetrahymena cells with a TtVPS13A knockout mutation displayed impaired phagocytosis. Specifically, they grew slowly under conditions where phagocytosis is essential, they formed few phagosomes, and the digestion of phagosomal contents was delayed compared to wild-type cells. Overall, these results provide evidence that the TtVPS13A protein is required for efficient phagocytosis.
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Abstract
Cells need a constant supply of precursors to enable the production of macromolecules to sustain growth and survival. Unlike metazoans, unicellular eukaryotes depend exclusively on the extracellular medium for this supply. When environmental nutrients become depleted, existing cytoplasmic components will be catabolized by (macro)autophagy in order to re-use building blocks and to support ATP production. In many cases, autophagy takes care of cellular housekeeping to sustain cellular viability. Autophagy encompasses a multitude of related and often highly specific processes that are implicated in both biogenetic and catabolic processes. Recent data indicate that in some unicellular eukaryotes that undergo profound differentiation during their life cycle (e.g. kinetoplastid parasites and amoebes), autophagy is essential for the developmental change that allows the cell to adapt to a new host or form spores. This review summarizes the knowledge on the molecular mechanisms of autophagy as well as the cytoplasm-to-vacuole-targeting pathway, pexophagy, mitophagy, ER-phagy, ribophagy and piecemeal microautophagy of the nucleus, all highly selective forms of autophagy that have first been uncovered in yeast species. Additionally, a detailed analysis will be presented on the state of knowledge on autophagy in non-yeast unicellular eukaryotes with emphasis on the role of this process in differentiation.
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Affiliation(s)
- Jan A K W Kiel
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, PO Box 14, 9750 Haren, The Netherlands.
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15
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Sawai S, Guan XJ, Kuspa A, Cox EC. High-throughput analysis of spatio-temporal dynamics in Dictyostelium. Genome Biol 2007; 8:R144. [PMID: 17659086 PMCID: PMC2323234 DOI: 10.1186/gb-2007-8-7-r144] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 06/25/2007] [Accepted: 07/21/2007] [Indexed: 11/20/2022] Open
Abstract
We demonstrate a time-lapse video approach that allows rapid examination of the spatio-temporal dynamics of Dictyostelium cell populations. Quantitative information was gathered by sampling life histories of more than 2,000 mutant clones from a large mutagenesis collection. Approximately 4% of the clonal lines showed a mutant phenotype at one stage. Many of these could be ordered by clustering into functional groups. The dataset allows one to search and retrieve movies on a gene-by-gene and phenotype-by-phenotype basis.
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Affiliation(s)
- Satoshi Sawai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- ERATO Complex Systems Biology Project, JST, Tokyo 153-8902, Japan
| | - Xiao-Juan Guan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Adam Kuspa
- Departments of Biochemistry and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Edward C Cox
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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Kurano Y, Nakamura M, Ichiba M, Matsuda M, Mizuno E, Kato M, Agemura A, Izumo S, Sano A. In vivo distribution and localization of chorein. Biochem Biophys Res Commun 2006; 353:431-5. [PMID: 17188237 DOI: 10.1016/j.bbrc.2006.12.059] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 12/07/2006] [Indexed: 11/17/2022]
Abstract
Chorea-acanthocytosis (ChAc) is a hereditary neurodegenerative disorder caused by loss of function mutations in the VPS13A gene encoding chorein. In this study, we produced an antibody against chorein and examined its protein-level expression and localization in mouse. Immunoblot analysis revealed that chorein was expressed in a gene dose-dependent manner in the VPS13A deletion-mice that we recently developed, which confirms the sensitivity of the antibody. Chorein was highly expressed in testis, kidney, spleen, and brain, and was expressed ubiquitously in various brain regions. Subcellular analysis of the brain showed high levels of chorein in microsomal and synaptosomal fractions. Immunohistochemically, chorein-like immunoreactivity was ubiquitously observed in the brain in the neuronal perinuclear region, cytoplasm and fibers. In testis and kidney, clear cell-specific patterns of chorein-like immunoreactivity were detected. Our findings provide basic information on chorein in vivo and may contribute to taking the first step toward understanding molecular pathogenesis of ChAc.
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Affiliation(s)
- Yutaka Kurano
- Department of Psychiatry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
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17
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Tekinay T, Wu MY, Otto GP, Anderson OR, Kessin RH. Function of the Dictyostelium discoideum Atg1 kinase during autophagy and development. EUKARYOTIC CELL 2006; 5:1797-806. [PMID: 17031001 PMCID: PMC1595346 DOI: 10.1128/ec.00342-05] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
When starved, the amoebae of Dictyostelium discoideum initiate a developmental process that results in the formation of fruiting bodies in which stalks support balls of spores. The nutrients and energy necessary for development are provided by autophagy. Atg1 is a protein kinase that regulates the induction of autophagy in the budding yeast Saccharomyces cerevisiae. In addition to a conserved kinase domain, Dictyostelium Atg1 has a C-terminal region that has significant homology to the Caenorhabditis elegans and mammalian Atg1 homologues but not to the budding yeast Atg1. We investigated the function of the kinase and conserved C-terminal domains of D. discoideum Atg1 (DdAtg1) and showed that these domains are essential for autophagy and development. Kinase-negative DdAtg1 acts in a dominant-negative fashion, resulting in a mutant phenotype when expressed in the wild-type cells. Green fluorescent protein-tagged kinase-negative DdAtg1 colocalizes with red fluorescent protein (RFP)-tagged DdAtg8, a marker of preautophagosomal structures and autophagosomes. The conserved C-terminal region is essential for localization of kinase-negative DdAtg1 to autophagosomes labeled with RFP-tagged Dictyostelium Atg8. The dominant-negative effect of the kinase-defective mutant also depends on the C-terminal domain. In cells expressing dominant-negative DdAtg1, autophagosomes are formed and accumulate but seem not to be functional. By using a temperature-sensitive DdAtg1, we showed that DdAtg1 is required throughout development; development halts when the cells are shifted to the restrictive temperature, but resumes when cells are returned to the permissive temperature.
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Affiliation(s)
- Turgay Tekinay
- Department of Anatomy and Cell Biology, P&S 12-517, Columbia University, 630 West 168th St., New York, NY 10032, USA
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Kurano Y, Nakamura M, Ichiba M, Matsuda M, Mizuno E, Kato M, Izumo S, Sano A. Chorein deficiency leads to upregulation of gephyrin and GABAA receptor. Biochem Biophys Res Commun 2006; 351:438-42. [PMID: 17070500 DOI: 10.1016/j.bbrc.2006.10.070] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 10/09/2006] [Indexed: 11/18/2022]
Abstract
Chorea-acanthocytosis (ChAc) is a hereditary neurodegenerative disorder caused by loss of function mutations in the VPS13A gene encoding chorein. Recently, using a gene-targeting technique to delete exons 60-61, we produced a ChAc-model mouse that corresponds to a human disease mutation. In this study, a comparative microarray analysis of gene expression in the striatum revealed an increased level of gephyrin gene expression in the ChAc-model mice compared with wild type mice. Since gephyrin is known as a GABA(A) receptor-anchoring protein, we compared the protein-level expression and localization of gephyrin and the GABA(A) receptor alpha1 (GABRA1) and gamma2 (GABRG2) subunits. Gephyrin and GABRG2 immunoreactivities in the striatum and hippocampus of the ChAc-model mice were significantly higher than those in the wild types. Our results suggest that chorein functional loss may lead to a compensatory upregulation of gephyrin and GABRG2 in the pathologic condition in ChAc.
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Affiliation(s)
- Yutaka Kurano
- Department of Psychiatry, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8520, Japan
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Mendoza MC, Du F, Iranfar N, Tang N, Ma H, Loomis WF, Firtel RA. Loss of SMEK, a novel, conserved protein, suppresses MEK1 null cell polarity, chemotaxis, and gene expression defects. Mol Cell Biol 2005; 25:7839-53. [PMID: 16107728 PMCID: PMC1190274 DOI: 10.1128/mcb.25.17.7839-7853.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
MEK/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase signaling is imperative for proper chemotaxis. Dictyostelium mek1(-) (MEK1 null) and erk1(-) cells exhibit severe defects in cell polarization and directional movement, but the molecules responsible for the mek1(-) and erk1(-) chemotaxis defects are unknown. Here, we describe a novel, evolutionarily conserved gene and protein (smkA and SMEK, respectively), whose loss partially suppresses the mek1(-) chemotaxis phenotypes. SMEK also has MEK1-independent functions: SMEK, but not MEK1, is required for proper cytokinesis during vegetative growth, timely exit from the mound stage during development, and myosin II assembly. SMEK localizes to the cell cortex through an EVH1 domain at its N terminus during vegetative growth. At the onset of development, SMEK translocates to the nucleus via a nuclear localization signal (NLS) at its C terminus. The importance of SMEK's nuclear localization is demonstrated by our findings that a mutant lacking the EVH1 domain complements SMEK deficiency, whereas a mutant lacking the NLS does not. Microarray analysis reveals that some genes are precociously expressed in mek1(-) and erk1(-) cells. The misexpression of some of these genes is suppressed in the smkA deletion. These data suggest that loss of MEK1/ERK1 signaling compromises gene expression and chemotaxis in a SMEK-dependent manner.
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Affiliation(s)
- Michelle C Mendoza
- Section of Cell and Developmental Biology, Division of Biological Sciences, Center for Molecular Genetics, University of California, San Diego, La Jolla, 92093-0380, USA
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Neuroacanthocytosis. NEURODEGENER DIS 2005. [DOI: 10.1017/cbo9780511544873.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Mattei S, Ryves WJ, Blot B, Sadoul R, Harwood AJ, Satre M, Klein G, Aubry L. Dd-Alix, a conserved endosome-associated protein, controls Dictyostelium development. Dev Biol 2005; 279:99-113. [PMID: 15708561 DOI: 10.1016/j.ydbio.2004.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 11/30/2004] [Accepted: 12/03/2004] [Indexed: 11/21/2022]
Abstract
We have characterized the Dictyostelium homolog of the mammalian protein Alix. Dd-Alix is encoded by a single gene and is expressed during vegetative growth and multicellular development. We showed that the alx null strain fails to complete its developmental program. Past the tight aggregate stage, morphogenesis is impaired, leading to markedly aberrant structures containing vacuolated and undifferentiated cells but no mature spores. The developmental defect is cell-autonomous as most cells remain of the PstB type even when mixed with wild-type cells. Complementation analysis with different Alix constructs allowed the identification of a 101-residue stretch containing a coiled-coil domain essential for Alix function. In addition, we showed that the protein associates in part with vesicular structures and that its distribution on a Percoll gradient overlaps that of the endocytic marker Vamp7. Dd-Alix also co-localizes with Dd-Vps32. In view of our data, and given the role of Vps32 proteins in membrane protein sorting and multivesicular body formation in yeast and mammals, we hypothesize that the developmental defects of the alx null strain result from abnormal trafficking of cell-surface receptors.
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Affiliation(s)
- Sara Mattei
- The Laboratoire de Biochimie et Biophysique des Systèmes Intégrés (UMR 5092 CNRS-CEA-UJF), DRDC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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Velayos-Baeza A, Vettori A, Copley RR, Dobson-Stone C, Monaco AP. Analysis of the human VPS13 gene family. Genomics 2005; 84:536-49. [PMID: 15498460 DOI: 10.1016/j.ygeno.2004.04.012] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Accepted: 04/19/2004] [Indexed: 01/11/2023]
Abstract
The gene mutated in chorea-acanthocytosis (CHAC; approved gene symbol VPS13A) encodes chorein, a protein similar to yeast Vps13p. We detected several similar putative human proteins by BLAST analysis of chorein. We characterized the structure of three new genes encoding these CHAC-similar proteins, located on chromosomes 1p36, 8q22, and 15q21. The most similar gene in yeast to all four human genes is Vps13, and therefore the human genes were named VPS13A (CHAC, 9q21), VPS13B (8q22), VPS13C (15q21), and VPS13D (1p36). VPS13B has recently been reported as COH1, altered in Cohen syndrome. For each gene, we describe several alternative splicing variants; at least two transcripts per gene are major forms. The expression pattern of these genes is ubiquitous, with some tissue-specific differences between several transcript variants. Protein sequence comparisons suggest that intramolecular duplications have played an important role in the evolution of this gene family.
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Affiliation(s)
- Antonio Velayos-Baeza
- Wellcome Trust Centre for Human Genetics, University of Oxford, Headington, OX3 7BN Oxford, UK
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Dobson-Stone C, Danek A, Rampoldi L, Hardie RJ, Chalmers RM, Wood NW, Bohlega S, Dotti MT, Federico A, Shizuka M, Tanaka M, Watanabe M, Ikeda Y, Brin M, Goldfarb LG, Karp BI, Mohiddin S, Fananapazir L, Storch A, Fryer AE, Maddison P, Sibon I, Trevisol-Bittencourt PC, Singer C, Caballero IR, Aasly JO, Schmierer K, Dengler R, Hiersemenzel LP, Zeviani M, Meiner V, Lossos A, Johnson S, Mercado FC, Sorrentino G, Dupré N, Rouleau GA, Volkmann J, Arpa J, Lees A, Geraud G, Chouinard S, Németh A, Monaco AP. Mutational spectrum of the CHAC gene in patients with chorea-acanthocytosis. Eur J Hum Genet 2002; 10:773-81. [PMID: 12404112 DOI: 10.1038/sj.ejhg.5200866] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2002] [Revised: 06/28/2002] [Accepted: 07/01/2002] [Indexed: 11/09/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) is an autosomal recessive neurological disorder whose characteristic features include hyperkinetic movements and abnormal red blood cell morphology. Mutations in the CHAC gene on 9q21 were recently found to cause chorea-acanthocytosis. CHAC encodes a large, novel protein with a yeast homologue implicated in protein sorting. In this study, all 73 exons plus flanking intronic sequence in CHAC were screened for mutations by denaturing high-performance liquid chromatography in 43 probands with ChAc. We identified 57 different mutations, 54 of which have not previously been reported, in 39 probands. The novel mutations comprise 15 nonsense, 22 insertion/deletion, 15 splice-site and two missense mutations and are distributed throughout the CHAC gene. Three mutations were found in multiple families within this or our previous study. The preponderance of mutations that are predicted to cause absence of gene product is consistent with the recessive inheritance of this disease. The high proportion of splice-site mutations found is probably a reflection of the large number of exons that comprise the CHAC gene. The CHAC protein product, chorein, appears to have a certain tolerance to amino-acid substitutions since only two out of nine substitutions described here appear to be pathogenic.
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Affiliation(s)
- C Dobson-Stone
- The Wellcome Trust Centre For Human Genetics, University of Oxford, UK
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Ueno S, Maruki Y, Nakamura M, Tomemori Y, Kamae K, Tanabe H, Yamashita Y, Matsuda S, Kaneko S, Sano A. The gene encoding a newly discovered protein, chorein, is mutated in chorea-acanthocytosis. Nat Genet 2001; 28:121-2. [PMID: 11381254 DOI: 10.1038/88825] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chorea-acanthocytosis is a neurodegenerative disorder with peripheral red cell acanthocytosis. Linkage of chorea-acanthocytosis to chromosome 9q21 has been found. We refined the locus region and identified a previously unknown, full-length cDNA encoding a presumably structural protein, which we called chorein. We found a deletion in the coding region of the cDNA leading to a frame shift resulting in the production of a truncated protein in both alleles of patients and in single alleles of obligate carriers.
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Affiliation(s)
- S Ueno
- Department of Neuropsychiatry, Ehime University School of Medicine, Shigenobu, Ehime, Japan
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