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Strbak O, Balejcikova L, Kmetova M, Gombos J, Trancikova A, Pokusa M, Kopcansky P. Quantification of Iron Release from Native Ferritin and Magnetoferritin Induced by Vitamins B 2 and C. Int J Mol Sci 2020; 21:E6332. [PMID: 32878313 PMCID: PMC7504058 DOI: 10.3390/ijms21176332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/23/2020] [Accepted: 08/30/2020] [Indexed: 12/18/2022] Open
Abstract
Various pathological processes in humans are associated with biogenic iron accumulation and the mineralization of iron oxide nanoparticles, especially magnetite. Ferritin has been proposed as a precursor to pathological magnetite mineralization. This study quantifies spectroscopically the release of ferrous ions from native ferritin and magnetoferritin as a model system for pathological ferritin in the presence of potent natural reducing agents (vitamins C and B2) over time. Ferrous cations are required for the transformation of ferrihydrite (physiological) into a magnetite (pathological) mineral core and are considered toxic at elevated levels. The study shows a significant difference in the reduction and iron release from native ferritin compared to magnetoferritin for both vitamins. The amount of reduced iron formed from a magnetoferritin mineral core is two to five times higher than from native ferritin. Surprisingly, increasing the concentration of the reducing agent affects only iron release from native ferritin. Magnetoferritin cores with different loading factors seem to be insensitive to different concentrations of vitamins. An alternative hypothesis of human tissue magnetite mineralization and the process of iron-induced pathology is proposed. The results could contribute to evidence of the molecular mechanisms of various iron-related pathologies, including neurodegeneration.
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Affiliation(s)
- Oliver Strbak
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (A.T.); (M.P.)
| | - Lucia Balejcikova
- Institute of Hydrology, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovakia;
| | - Martina Kmetova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (M.K.); (J.G.)
| | - Jan Gombos
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (M.K.); (J.G.)
| | - Alzbeta Trancikova
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (A.T.); (M.P.)
| | - Michal Pokusa
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (A.T.); (M.P.)
| | - Peter Kopcansky
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia;
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Trancikova A, Kovacova E, Ru F, Varga K, Brozmanova M, Tatar M, Kollarik M. Distinct Expression of Phenotypic Markers in Placodes- and Neural Crest-Derived Afferent Neurons Innervating the Rat Stomach. Dig Dis Sci 2018; 63:383-394. [PMID: 29275446 DOI: 10.1007/s10620-017-4883-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 12/12/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Visceral pain is initiated by activation of primary afferent neurons among which the capsaicin-sensitive (TRPV1-positive) neurons play an important role. The stomach is a common source of visceral pain. Similar to other organs, the stomach receives dual spinal and vagal afferent innervation. Developmentally, spinal dorsal root ganglia (DRG) and vagal jugular neurons originate from embryonic neural crest and vagal nodose neurons originate from placodes. In thoracic organs the neural crest- and placodes-derived TRPV1-positive neurons have distinct phenotypes differing in activation profile, neurotrophic regulation and reflex responses. It is unknown to whether such distinction exists in the stomach. AIMS We hypothesized that gastric neural crest- and placodes-derived TRPV1-positive neurons express phenotypic markers indicative of placodes and neural crest phenotypes. METHODS Gastric DRG and vagal neurons were retrogradely traced by DiI injected into the rat stomach wall. Single-cell RT-PCR was performed on traced gastric neurons. RESULTS Retrograde tracing demonstrated that vagal gastric neurons locate exclusively into the nodose portion of the rat jugular/petrosal/nodose complex. Gastric DRG TRPV1-positive neurons preferentially expressed markers PPT-A, TrkA and GFRα3 typical for neural crest-derived TRPV1-positive visceral neurons. In contrast, gastric nodose TRPV1-positive neurons preferentially expressed markers P2X2 and TrkB typical for placodes-derived TRPV1-positive visceral neurons. Differential expression of neural crest and placodes markers was less pronounced in TRPV1-negative DRG and nodose populations. CONCLUSIONS There are phenotypic distinctions between the neural crest-derived DRG and placodes-derived vagal nodose TRPV1-positive neurons innervating the rat stomach that are similar to those described in thoracic organs.
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Affiliation(s)
- Alzbeta Trancikova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Eva Kovacova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Fei Ru
- Department of Medicine, The Johns Hopkins University School of Medicine, Johns Hopkins Asthma Center, RM 1A.2, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA
| | - Kristian Varga
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Mariana Brozmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Milos Tatar
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Marian Kollarik
- Department of Medicine, The Johns Hopkins University School of Medicine, Johns Hopkins Asthma Center, RM 1A.2, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA.
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Hennel M, Harsanyiova J, Ru F, Zatko T, Brozmanova M, Trancikova A, Tatar M, Kollarik M. Structure of vagal afferent nerve terminal fibers in the mouse trachea. Respir Physiol Neurobiol 2018; 249:35-46. [PMID: 29306061 DOI: 10.1016/j.resp.2018.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 12/23/2017] [Accepted: 01/01/2018] [Indexed: 12/20/2022]
Abstract
The structure of primary afferent nerve terminals profoundly influences their function. While the complex vagal airway nerve terminals (stretch receptors, cough receptors and neuroepithelial bodies) were thoroughly characterized, much less is known about the structure of airway nerves that do not form distinct complex terminals (often termed free nerve fibers). We selectively induced expression of GFP in vagal afferent nerves in the mouse by transfection with AAV-GFP virus vector and visualized nerve terminals in the trachea by whole organ confocal imaging. Based on structural characteristics we identified four types of vagal afferent nerve fiber terminals in the trachea. Importantly, we found that distinct compartments of tracheal tissue are innervated by distinct nerve fiber terminal types in a non-overlapping manner. Thus, separate terminal types innervate tracheal epithelium vs. anterolateral tracheal wall containing cartilaginous rings and ligaments vs. dorsal wall containing smooth muscle. Our results will aid the study of structure-function relationships in vagal airway afferent nerves and regulation of respiratory reflexes.
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Affiliation(s)
- Michal Hennel
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Jana Harsanyiova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Fei Ru
- The Johns Hopkins University School of Medicine, Department of Medicine, Division of Allergy and Clinical Immunology, Baltimore, MD 21224, United States
| | - Tomas Zatko
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Mariana Brozmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Alzbeta Trancikova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Milos Tatar
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU and Biomedical Center Martin, 036 01 Martin, Slovakia
| | - Marian Kollarik
- The Johns Hopkins University School of Medicine, Department of Medicine, Division of Allergy and Clinical Immunology, Baltimore, MD 21224, United States.
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Biosa A, Trancikova A, Civiero L, Glauser L, Bubacco L, Greggio E, Moore DJ. GTPase activity regulates kinase activity and cellular phenotypes of Parkinson's disease-associated LRRK2. Hum Mol Genet 2012; 22:1140-56. [PMID: 23241358 DOI: 10.1093/hmg/dds522] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in the LRRK2 gene cause autosomal dominant Parkinson's disease. LRRK2 encodes a multi-domain protein containing a Ras-of-complex (Roc) GTPase domain, a C-terminal of Roc domain and a protein kinase domain. LRRK2 can function as a GTPase and protein kinase, although the interplay between these two enzymatic domains is poorly understood. Although guanine nucleotide binding is critically required for the kinase activity of LRRK2, the contribution of GTP hydrolysis is not known. In general, the molecular determinants regulating GTPase activity and how the GTPase domain contributes to the properties of LRRK2 remain to be clarified. Here, we identify a number of synthetic missense mutations in the GTPase domain that functionally modulate GTP binding and GTP hydrolysis and we employ these mutants to comprehensively explore the contribution of GTPase activity to the kinase activity and cellular phenotypes of LRRK2. Our data demonstrate that guanine nucleotide binding and, to a lesser extent, GTP hydrolysis are required for maintaining normal kinase activity and both activities contribute to the GTP-dependent activation of LRRK2 kinase activity. Guanine nucleotide binding but not GTP hydrolysis regulates the dimerization, structure and stability of LRRK2. Furthermore, GTP hydrolysis regulates the LRRK2-dependent inhibition of neurite outgrowth in primary cortical neurons but is unable to robustly modulate the effects of the familial G2019S mutation. Our study elucidates the role of GTPase activity in regulating kinase activity and cellular phenotypes of LRRK2 and has important implications for the validation of the GTPase domain as a molecular target for attenuating LRRK2-mediated neurodegeneration.
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Affiliation(s)
- Alice Biosa
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fe´de´ rale de Lausanne (EPFL), Lausanne 1015, Switzerland
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Trancikova A, Mamais A, Webber PJ, Stafa K, Tsika E, Glauser L, West AB, Bandopadhyay R, Moore DJ. Phosphorylation of 4E-BP1 in the mammalian brain is not altered by LRRK2 expression or pathogenic mutations. PLoS One 2012; 7:e47784. [PMID: 23082216 PMCID: PMC3474772 DOI: 10.1371/journal.pone.0047784] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/17/2012] [Indexed: 12/20/2022] Open
Abstract
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are a common cause of autosomal dominant familial Parkinson's disease (PD). LRRK2 encodes a multi-domain protein containing GTPase and kinase enzymatic domains. Disease-associated mutations in LRRK2 variably influence enzymatic activity with the common G2019S variant leading to enhanced kinase activity. Mutant LRRK2 induces neuronal toxicity through a kinase-dependent mechanism suggesting that kinase activity is important for mediating the pathogenic effects of LRRK2 mutations. A number of LRRK2 kinase substrates have been identified in vitro but whether they represent authentic physiological substrates in mammalian cells or tissues is not yet clear. The eukaryotic initiation factor 4E (eIF4E)-binding protein, 4E-BP1, was recently identified as a potential substrate of LRRK2 kinase activity in vitro and in Drosophila with phosphorylation occurring at Thr37 and Thr46. Here, we explore a potential interaction of LRRK2 and 4E-BP1 in mammalian cells and brain. We find that LRRK2 can weakly phosphorylate 4E-BP1 in vitro but LRRK2 overexpression is not able to alter endogenous 4E-BP1 phosphorylation in mammalian cells. In mammalian neurons LRRK2 and 4E-BP1 display minimal co-localization, whereas the subcellular distribution, protein complex formation and covalent post-translational modification of endogenous 4E-BP1 are not altered in the brains of LRRK2 knockout or mutant LRRK2 transgenic mice. In the brain, the phosphorylation of 4E-BP1 at Thr37 and Thr46 does not change in LRRK2 knockout or mutant LRRK2 transgenic mice, nor is 4E-BP1 phosphorylation altered in idiopathic or G2019S mutant PD brains. Collectively, our results suggest that 4E-BP1 is neither a major nor robust physiological substrate of LRRK2 in mammalian cells or brain.
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Affiliation(s)
- Alzbeta Trancikova
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Adamantios Mamais
- Reta Lila Weston Institute of Neurological Disease, University College London Institute of Neurology, London, United Kingdom
| | - Philip J. Webber
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Klodjan Stafa
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Elpida Tsika
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Liliane Glauser
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Andrew B. West
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Rina Bandopadhyay
- Reta Lila Weston Institute of Neurological Disease, University College London Institute of Neurology, London, United Kingdom
| | - Darren J. Moore
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail:
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Abstract
UNLABELLED Mitochondria are highly dynamic, multifunctional organelles. Aside from their major role in energy metabolism, they are also crucial for many cellular processes including neurotransmission, synaptic maintenance, calcium homeostasis, cell death, and neuronal survival. SIGNIFICANCE Increasing evidence supports a role for abnormal mitochondrial function in the molecular pathophysiology of Parkinson's disease (PD). For three decades we have known that mitochondrial toxins are capable of producing clinical parkinsonism in humans. PD is the most common neurodegenerative movement disorder that is characterized by the progressive loss of substantia nigra dopaminergic neurons leading to a deficiency of striatal dopamine. Although the neuropathology underlying the disease is well defined, it remains unclear why nigral dopaminergic neurons degenerate and die. RECENT ADVANCES Most PD cases are idiopathic, but there are rare familial cases. Mutations in five genes are known to unambiguously cause monogenic familial PD: α-synuclein, parkin, DJ-1, PTEN-induced kinase 1 (PINK1), and leucine-rich repeat kinase 2 (LRRK2). These key molecular players are proteins of seemingly diverse function, but with potentially important roles in mitochondrial maintenance and function. Cell and animal-based genetic models have provided indispensable tools for understanding the molecular basis of PD, and have provided additional evidence implicating mitochondrial dysfunction as a primary pathogenic pathway leading to the demise of dopaminergic neurons in PD. CRITICAL ISSUES Here, we critically discuss the evidence for mitochondrial dysfunction in genetic animal models of PD, and evaluate whether abnormal mitochondrial function represents a cause or consequence of disease pathogenesis. FUTURE DIRECTIONS Mitochondria may represent a potential target for the development of disease-modifying therapies.
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Affiliation(s)
- Alzbeta Trancikova
- Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Stafa K, Trancikova A, Webber PJ, Glauser L, West AB, Moore DJ. GTPase activity and neuronal toxicity of Parkinson's disease-associated LRRK2 is regulated by ArfGAP1. PLoS Genet 2012; 8:e1002526. [PMID: 22363216 PMCID: PMC3280333 DOI: 10.1371/journal.pgen.1002526] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 12/11/2011] [Indexed: 11/18/2022] Open
Abstract
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of autosomal dominant familial Parkinson's disease (PD) and also contribute to idiopathic PD. LRRK2 encodes a large multi-domain protein with GTPase and kinase activity. Initial data indicates that an intact functional GTPase domain is critically required for LRRK2 kinase activity. PD–associated mutations in LRRK2, including the most common G2019S variant, have variable effects on enzymatic activity but commonly alter neuronal process morphology. The mechanisms underlying the intrinsic and extrinsic regulation of LRRK2 GTPase and kinase activity, and the pathogenic effects of familial mutations, are incompletely understood. Here, we identify a novel functional interaction between LRRK2 and ADP-ribosylation factor GTPase-activating protein 1 (ArfGAP1). LRRK2 and ArfGAP1 interact in vitro in mammalian cells and in vivo in brain, and co-localize in the cytoplasm and at Golgi membranes. PD–associated and functional mutations that alter the GTPase activity of LRRK2 modulate the interaction with ArfGAP1. The GTP hydrolysis activity of LRRK2 is markedly enhanced by ArfGAP1 supporting a role for ArfGAP1 as a GTPase-activating protein for LRRK2. Unexpectedly, ArfGAP1 promotes the kinase activity of LRRK2 suggesting a potential role for GTP hydrolysis in kinase activation. Furthermore, LRRK2 robustly and directly phosphorylates ArfGAP1 in vitro. Silencing of ArfGAP1 expression in primary cortical neurons rescues the neurite shortening phenotype induced by G2019S LRRK2 overexpression, whereas the co-expression of ArfGAP1 and LRRK2 synergistically promotes neurite shortening in a manner dependent upon LRRK2 GTPase activity. Neurite shortening induced by ArfGAP1 overexpression is also attenuated by silencing of LRRK2. Our data reveal a novel role for ArfGAP1 in regulating the GTPase activity and neuronal toxicity of LRRK2; reciprocally, LRRK2 phosphorylates ArfGAP1 and is required for ArfGAP1 neuronal toxicity. ArfGAP1 may represent a promising target for interfering with LRRK2-dependent neurodegeneration in familial and sporadic PD. Parkinson's disease (PD) is the most common neurodegenerative movement disorder. Current therapies for treating PD are symptomatic and rely on restoring dopamine signaling. There is presently no cure for PD. PD is typically a sporadic disease, although 5%–10% of cases are known to have a familial origin. Mutations in at least seven genes are known to cause familial forms of PD, with mutations in the leucine-rich repeat kinase 2 (LRRK2) gene at the PARK8 locus representing the most common cause of familial and sporadic PD. The LRRK2 gene encodes a multi-domain protein with two enzymatic activities, GTPase and kinase, and familial mutations are known to variably influence these activities. Familial mutations in LRRK2 promote toxicity in cultured neurons, which is dependent on both GTPase and kinase activity. The factors regulating the GTPase activity of LRRK2 are poorly understood. Here, we identify the ArfGAP1 protein as a novel regulator of LRRK2 GTPase and kinase activity as well as neuronal toxicity induced by LRRK2. ArfGAP1 also serves as a novel substrate for phosphorylation mediated by LRRK2 kinase activity. ArfGAP1 may therefore represent a promising molecular target for interfering with neurodegeneration due to LRRK2 mutations in familial and sporadic forms of PD.
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Affiliation(s)
- Klodjan Stafa
- Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Alzbeta Trancikova
- Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Philip J. Webber
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Liliane Glauser
- Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Andrew B. West
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Darren J. Moore
- Laboratory of Molecular Neurodegenerative Research, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- * E-mail:
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Ramonet D, Podhajska A, Stafa K, Sonnay S, Trancikova A, Tsika E, Pletnikova O, Troncoso JC, Glauser L, Moore DJ. PARK9-associated ATP13A2 localizes to intracellular acidic vesicles and regulates cation homeostasis and neuronal integrity. Hum Mol Genet 2011; 21:1725-43. [PMID: 22186024 DOI: 10.1093/hmg/ddr606] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in the ATP13A2 gene (PARK9, OMIM 610513) cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome and early-onset parkinsonism. ATP13A2 is an uncharacterized protein belonging to the P(5)-type ATPase subfamily that is predicted to regulate the membrane transport of cations. The physiological function of ATP13A2 in the mammalian brain is poorly understood. Here, we demonstrate that ATP13A2 is localized to intracellular acidic vesicular compartments in cultured neurons. In the human brain, ATP13A2 is localized to pyramidal neurons within the cerebral cortex and dopaminergic neurons of the substantia nigra. ATP13A2 protein levels are increased in nigral dopaminergic and cortical pyramidal neurons of Parkinson's disease brains compared with normal control brains. ATP13A2 levels are increased in cortical neurons bearing Lewy bodies (LBs) compared with neurons without LBs. Using short hairpin RNA-mediated silencing or overexpression to explore the function of ATP13A2, we find that modulating the expression of ATP13A2 reduces the neurite outgrowth of cultured midbrain dopaminergic neurons. We also find that silencing of ATP13A2 expression in cortical neurons alters the kinetics of intracellular pH in response to cadmium exposure. Furthermore, modulation of ATP13A2 expression leads to reduced intracellular calcium levels in cortical neurons. Finally, we demonstrate that silencing of ATP13A2 expression induces mitochondrial fragmentation in neurons. Oppositely, overexpression of ATP13A2 delays cadmium-induced mitochondrial fragmentation in neurons consistent with a neuroprotective effect. Collectively, this study reveals a number of intriguing neuronal phenotypes due to the loss- or gain-of-function of ATP13A2 that support a role for this protein in regulating intracellular cation homeostasis and neuronal integrity.
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Affiliation(s)
- David Ramonet
- Laboratory of Molecular Neurodegenerative Research, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Trancikova A, Ramonet D, Moore DJ. Genetic Mouse Models of Neurodegenerative Diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 100:419-82. [DOI: 10.1016/b978-0-12-384878-9.00012-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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