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Rinné S, Stallmeyer B, Pinggera A, Netter MF, Matschke LA, Dittmann S, Kirchhefer U, Neudorf U, Opp J, Striessnig J, Decher N, Schulze-Bahr E. Whole Exome Sequencing Identifies a Heterozygous Variant in the Cav1.3 Gene CACNA1D Associated with Familial Sinus Node Dysfunction and Focal Idiopathic Epilepsy. Int J Mol Sci 2022; 23:ijms232214215. [PMID: 36430690 PMCID: PMC9693521 DOI: 10.3390/ijms232214215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/04/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Cav1.3 voltage-gated L-type calcium channels (LTCCs) are involved in cardiac pacemaking, hearing and hormone secretion, but are also expressed postsynaptically in neurons. So far, homozygous loss of function mutations in CACNA1D encoding the Cav1.3 α1-subunit are described in congenital sinus node dysfunction and deafness. In addition, germline mutations in CACNA1D have been linked to neurodevelopmental syndromes including epileptic seizures, autism, intellectual disability and primary hyperaldosteronism. Here, a three-generation family with a syndromal phenotype of sinus node dysfunction, idiopathic epilepsy and attention deficit hyperactivity disorder (ADHD) is investigated. Whole genome sequencing and functional heterologous expression studies were used to identify the disease-causing mechanisms in this novel syndromal disorder. We identified a heterozygous non-synonymous variant (p.Arg930His) in the CACNA1D gene that cosegregated with the combined clinical phenotype in an autosomal dominant manner. Functional heterologous expression studies showed that the CACNA1D variant induces isoform-specific alterations of Cav1.3 channel gating: a gain of ion channel function was observed in the brain-specific short CACNA1D isoform (Cav1.3S), whereas a loss of ion channel function was seen in the long (Cav1.3L) isoform. The combined gain-of-function (GOF) and loss-of-function (LOF) induced by the R930H variant are likely to be associated with the rare combined clinical and syndromal phenotypes in the family. The GOF in the Cav1.3S variant with high neuronal expression is likely to result in epilepsy, whereas the LOF in the long Cav1.3L variant results in sinus node dysfunction.
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Affiliation(s)
- Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
| | - Birgit Stallmeyer
- Institute for Genetics of Heart Diseases (IfGH), University Hospital Muenster, 48149 Muenster, Germany
| | - Alexandra Pinggera
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Michael F. Netter
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
| | - Lina A. Matschke
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
| | - Sven Dittmann
- Institute for Genetics of Heart Diseases (IfGH), University Hospital Muenster, 48149 Muenster, Germany
| | - Uwe Kirchhefer
- Institute of Pharmacology and Toxicology, University Hospital Muenster, 48149 Muenster, Germany
| | - Ulrich Neudorf
- Zentrum für Kinder-und Jugendmedizin, Klinik für Kinderheilkunde III-Bereich Kardiologie, University Hospital Essen, 45147 Essen, Germany
| | - Joachim Opp
- Ev. Krankenhaus Oberhausen, 46047 Oberhausen, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
- Correspondence: (N.D.); (E.S.-B.); Tel.: +49-(0)6421/28-62148 (N.D.); +49-(0)251/83-55326 (E.S.-B.)
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), University Hospital Muenster, 48149 Muenster, Germany
- Correspondence: (N.D.); (E.S.-B.); Tel.: +49-(0)6421/28-62148 (N.D.); +49-(0)251/83-55326 (E.S.-B.)
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2
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Matschke LA, Komadowski MA, Stöhr A, Lee B, Henrich MT, Griesbach M, Rinné S, Geibl FF, Chiu WH, Koprich JB, Brotchie JM, Kiper AK, Dolga AM, Oertel WH, Decher N. Enhanced firing of locus coeruleus neurons and SK channel dysfunction are conserved in distinct models of prodromal Parkinson's disease. Sci Rep 2022; 12:3180. [PMID: 35210472 PMCID: PMC8873463 DOI: 10.1038/s41598-022-06832-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/07/2022] [Indexed: 12/21/2022] Open
Abstract
Parkinson's disease (PD) is clinically defined by the presence of the cardinal motor symptoms, which are associated with a loss of dopaminergic nigrostriatal neurons in the substantia nigra pars compacta (SNpc). While SNpc neurons serve as the prototypical cell-type to study cellular vulnerability in PD, there is an unmet need to extent our efforts to other neurons at risk. The noradrenergic locus coeruleus (LC) represents one of the first brain structures affected in Parkinson's disease (PD) and plays not only a crucial role for the evolving non-motor symptomatology, but it is also believed to contribute to disease progression by efferent noradrenergic deficiency. Therefore, we sought to characterize the electrophysiological properties of LC neurons in two distinct PD models: (1) in an in vivo mouse model of focal α-synuclein overexpression; and (2) in an in vitro rotenone-induced PD model. Despite the fundamental differences of these two PD models, α-synuclein overexpression as well as rotenone exposure led to an accelerated autonomous pacemaker frequency of LC neurons, accompanied by severe alterations of the afterhyperpolarization amplitude. On the mechanistic side, we suggest that Ca2+-activated K+ (SK) channels are mediators of the increased LC neuronal excitability, as pharmacological activation of these channels is sufficient to prevent increased LC pacemaking and subsequent neuronal loss in the LC following in vitro rotenone exposure. These findings suggest a role of SK channels in PD by linking α-synuclein- and rotenone-induced changes in LC firing rate to SK channel dysfunction.
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Affiliation(s)
- Lina A Matschke
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany.,Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany
| | - Marlene A Komadowski
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany
| | - Annette Stöhr
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany
| | - Bolam Lee
- Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany
| | - Martin T Henrich
- Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany
| | - Markus Griesbach
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany
| | - Fanni F Geibl
- Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany
| | - Wei-Hua Chiu
- Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany
| | - James B Koprich
- Krembil Research Institute, Toronto Western Hospital, University Health Network, 8KD402, Toronto, ON, M5T 2S8, Canada
| | - Jonathan M Brotchie
- Krembil Research Institute, Toronto Western Hospital, University Health Network, 8KD402, Toronto, ON, M5T 2S8, Canada
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany
| | - Amalia M Dolga
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Wolfgang H Oertel
- Clinic for Neurology, Philipps-University Marburg, 35043, Marburg, Germany.,Hertie Senior Research Professor of the Charitable Hertie Foundation, 60323, Frankfurt am Main, Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB, Philipps-University Marburg, 35037, Marburg, Germany.
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Ganjam GK, Bolte K, Matschke LA, Neitemeier S, Dolga AM, Höllerhage M, Höglinger GU, Adamczyk A, Decher N, Oertel WH, Culmsee C. Mitochondrial damage by α-synuclein causes cell death in human dopaminergic neurons. Cell Death Dis 2019; 10:865. [PMID: 31727879 PMCID: PMC6856124 DOI: 10.1038/s41419-019-2091-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/09/2019] [Accepted: 10/07/2019] [Indexed: 12/24/2022]
Abstract
Evolving concepts on Parkinson’s disease (PD) pathology suggest that α-synuclein (aSYN) promote dopaminergic neuron dysfunction and death through accumulating in the mitochondria. However, the consequence of mitochondrial aSYN localisation on mitochondrial structure and bioenergetic functions in neuronal cells are poorly understood. Therefore, we investigated deleterious effects of mitochondria-targeted aSYN in differentiated human dopaminergic neurons in comparison with wild-type (WT) aSYN overexpression and corresponding EGFP (enhanced green fluorescent protein)-expressing controls. Mitochondria-targeted aSYN enhanced mitochondrial reactive oxygen species (ROS) formation, reduced ATP levels and showed severely disrupted structure and function of the dendritic neural network, preceding neuronal death. Transmission electron microscopy illustrated distorted cristae and many fragmented mitochondria in response to WT-aSYN overexpression, and a complete loss of cristae structure and massively swollen mitochondria in neurons expressing mitochondria-targeted aSYN. Further, the analysis of mitochondrial bioenergetics in differentiated dopaminergic neurons, expressing WT or mitochondria-targeted aSYN, elicited a pronounced impairment of mitochondrial respiration. In a pharmacological compound screening, we found that the pan-caspase inhibitors QVD and zVAD-FMK, and a specific caspase-1 inhibitor significantly prevented aSYN-induced cell death. In addition, the caspase inhibitor QVD preserved mitochondrial function and neuronal network activity in the human dopaminergic neurons overexpressing aSYN. Overall, our findings indicated therapeutic effects by caspase-1 inhibition despite aSYN-mediated alterations in mitochondrial morphology and function.
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Affiliation(s)
- Goutham K Ganjam
- Institute for Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, Marburg, Germany. .,Department of Neurology, University of Marburg, Marburg, Germany. .,Center for Mind, Brain and Behaviour - CMBB, Marburg, Germany.
| | - Kathrin Bolte
- Laboratory for Cell Biology I, Department of Biology, University of Marburg, Marburg, Germany
| | - Lina A Matschke
- Institute of Physiology and Pathophysiology, University of Marburg, Marburg, Germany
| | - Sandra Neitemeier
- Institute for Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, Marburg, Germany
| | - Amalia M Dolga
- Institute for Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, Marburg, Germany.,Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
| | | | | | - Agata Adamczyk
- Department of Cellular Signaling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Niels Decher
- Institute of Physiology and Pathophysiology, University of Marburg, Marburg, Germany
| | - Wolfgang H Oertel
- Department of Neurology, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behaviour - CMBB, Marburg, Germany
| | - Carsten Culmsee
- Institute for Pharmacology and Clinical Pharmacy, Biochemical-Pharmacological Center, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behaviour - CMBB, Marburg, Germany.,Department of Pediatrics, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Silbernagel N, Walecki M, Schäfer MKH, Kessler M, Zobeiri M, Rinné S, Kiper AK, Komadowski MA, Vowinkel KS, Wemhöner K, Fortmüller L, Schewe M, Dolga AM, Scekic-Zahirovic J, Matschke LA, Culmsee C, Baukrowitz T, Monassier L, Ullrich ND, Dupuis L, Just S, Budde T, Fabritz L, Decher N. The VAMP-associated protein VAPB is required for cardiac and neuronal pacemaker channel function. FASEB J 2018; 32:6159-6173. [PMID: 29879376 PMCID: PMC6629115 DOI: 10.1096/fj.201800246r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels encode neuronal and cardiac pacemaker currents. The composition of pacemaker channel complexes in different tissues is poorly understood, and the presence of additional HCN modulating subunits was speculated. Here we show that vesicle-associated membrane protein-associated protein B (VAPB), previously associated with a familial form of amyotrophic lateral sclerosis 8, is an essential HCN1 and HCN2 modulator. VAPB significantly increases HCN2 currents and surface expression and has a major influence on the dendritic neuronal distribution of HCN2. Severe cardiac bradycardias in VAPB-deficient zebrafish and VAPB-/- mice highlight that VAPB physiologically serves to increase cardiac pacemaker currents. An altered T-wave morphology observed in the ECGs of VAPB-/- mice supports the recently proposed role of HCN channels for ventricular repolarization. The critical function of VAPB in native pacemaker channel complexes will be relevant for our understanding of cardiac arrhythmias and epilepsies, and provides an unexpected link between these diseases and amyotrophic lateral sclerosis.-Silbernagel, N., Walecki, M., Schäfer, M.-K. H., Kessler, M., Zobeiri, M., Rinné, S., Kiper, A. K., Komadowski, M. A., Vowinkel, K. S., Wemhöner, K., Fortmüller, L., Schewe, M., Dolga, A. M., Scekic-Zahirovic, J., Matschke, L. A., Culmsee, C., Baukrowitz, T., Monassier, L., Ullrich, N. D., Dupuis, L., Just, S., Budde, T., Fabritz, L., Decher, N. The VAMP-associated protein VAPB is required for cardiac and neuronal pacemaker channel function.
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Affiliation(s)
- Nicole Silbernagel
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Magdalena Walecki
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Martin K-H Schäfer
- Institute of Anatomy and Cell Biology, Philipps University, Marburg, Germany
| | - Mirjam Kessler
- Molecular Cardiology, Department of Internal Medicine II, University Hospital Ulm, Ulm, Germany
| | | | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Aytug K Kiper
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Marlene A Komadowski
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany.,Institute of Anatomy and Cell Biology, Philipps University, Marburg, Germany
| | - Kirsty S Vowinkel
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Konstantin Wemhöner
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Lisa Fortmüller
- Department of Cardiology II - Electrophysiology, University Hospital Münster, University of Münster, Munster, Germany
| | - Marcus Schewe
- Institute of Physiology, Christian-Albrechts University, Kiel, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, Phillips University, Marburg, Germany
| | - Jelena Scekic-Zahirovic
- Laboratoire de Pharmacologie et Toxicologie NeuroCardiovasculaire, Faculté de Médecine, Université de Strasbourg, Strasbourg, France
| | - Lina A Matschke
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, Phillips University, Marburg, Germany
| | - Thomas Baukrowitz
- Institute of Physiology, Christian-Albrechts University, Kiel, Germany
| | - Laurent Monassier
- Laboratoire de Pharmacologie et Toxicologie NeuroCardiovasculaire, Faculté de Médecine, Université de Strasbourg, Strasbourg, France
| | - Nina D Ullrich
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Luc Dupuis
- Laboratoire de Neurobiologie et Pharmacologie Cardiovasculaire, Faculté de Médecine, Université de Strasbourg, Strasbourg, France.,INSERM, Faculté de Médecine, Université de Strasbourg, Strasbourg, France
| | - Steffen Just
- Molecular Cardiology, Department of Internal Medicine II, University Hospital Ulm, Ulm, Germany
| | - Thomas Budde
- Institute for Physiology I, University of Münster, Munster, Germany
| | - Larissa Fabritz
- Department of Cardiology II - Electrophysiology, University Hospital Münster, University of Münster, Munster, Germany.,Institute of Cardiovascular Sciences, University Hospital Birmingham, University of Birmingham, Birmingham, United Kingdom.,Department of Cardiology, University Hospital Birmingham, University of Birmingham, Birmingham, United Kingdom.,Division of Rhythmology, Department of Genetic Epidemiology, University Hospital Münster, University of Münster, Munster, Germany.,Institute of Human Genetics, Department of Genetic Epidemiology, University Hospital Münster, University of Münster, Munster, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Phillips University, Marburg, Germany
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5
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Stallmeyer B, Kuß J, Kotthoff S, Zumhagen S, Vowinkel K, Rinné S, Matschke LA, Friedrich C, Schulze-Bahr E, Rust S, Seebohm G, Decher N, Schulze-Bahr E. A Mutation in the G-Protein Gene GNB2 Causes Familial Sinus Node and Atrioventricular Conduction Dysfunction. Circ Res 2017; 120:e33-e44. [PMID: 28219978 DOI: 10.1161/circresaha.116.310112] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/16/2017] [Accepted: 02/20/2017] [Indexed: 11/16/2022]
Abstract
RATIONALE Familial sinus node and atrioventricular conduction dysfunction is a rare disorder that leads to paroxysmal dizziness, fatigue, and syncope because of a temporarily or permanently reduced heart rate. To date, only a few genes for familial sinus and atrioventricular conduction dysfunction are known, and the majority of cases remain pathogenically unresolved. OBJECTIVE We aim to identify the disease gene in a large 3-generation family (n=25) with autosomal dominant sinus node dysfunction (SND) and atrioventricular block (AVB) and to characterize the mutation-related pathomechanisms in familial SND+AVB. METHODS AND RESULTS Genome-wide linkage analysis mapped the SND+AVB disease locus to chromosome 7q21.1-q31.1 (2-point logarithm of the odds score: 4.64; θ=0); in this region, targeted exome sequencing identified a novel heterozygous mutation (p.Arg52Leu) in the GNB2 gene that strictly cosegregated with the SND+AVB phenotype. GNB2 encodes the β2 subunit (Gβ2) of the heterotrimeric G-protein complex that is being released from G-protein-coupled receptors on vagal stimulation. In 2 heterologous expression systems (HEK-293T cells and Xenopus laevis oocytes), an enhanced activation of the G-protein-activated K+ channel (GIRK; Kir3.1/Kir3.4) was shown when mutant Gβ2 was coexpressed with Gγ2; this was in contrast to coexpression of mutant Gβ2-Gγ2 with other cardiac ion channels (HCN4, HCN2, and Cav1.2). Molecular dynamics simulations suggested a reduced binding property of mutant Gβ2 to cardiac GIRK channels when compared with native Gβ2. CONCLUSIONS A GNB2 gene mutation is associated with familial SND+AVB and leads to a sustained activation of cardiac GIRK channels, which is likely to hyperpolarize the myocellular membrane potential and thus reduces their spontaneous activity. Our findings describe for the first time a role of a mutant G-protein in the nonsyndromic pacemaker disease because of GIRK channel activation.
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Affiliation(s)
- Birgit Stallmeyer
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Johanna Kuß
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Stefan Kotthoff
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Sven Zumhagen
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Kirsty Vowinkel
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Susanne Rinné
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Lina A Matschke
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Corinna Friedrich
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Ellen Schulze-Bahr
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Stephan Rust
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Guiscard Seebohm
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Niels Decher
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.)
| | - Eric Schulze-Bahr
- From the Institute for Genetics of Heart Diseases, Department of Cardiology and Angiology, University Hospital Muenster, Germany (B.S., J.K., S.Z., C.F., E.S.-B., G.S., E.S.-B.); Department of Pediatric Cardiology (S.K.) and Department of General Pediatrics (S.R.), University Children's Hospital Muenster, Germany; and Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps University of Marburg, Germany (K.V., S.R., L.A.M., N.D.).
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6
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Streit AK, Matschke LA, Dolga AM, Rinné S, Decher N. RNA editing in the central cavity as a mechanism to regulate surface expression of the voltage-gated potassium channel Kv1.1. J Biol Chem 2014; 289:26762-26771. [PMID: 25100718 DOI: 10.1074/jbc.m113.545731] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Voltage-gated potassium (Kv) 1.1 channels undergo a specific enzymatic RNA deamination, generating a channel with a single amino acid exchange located in the inner pore cavity (Kv1.1(I400V)). We studied I400V-edited Kv1.1 channels in more detail and found that Kv1.1(I400V) gave rise to much smaller whole-cell currents than Kv1.1. To elucidate the mechanism behind this current reduction, we conducted electrophysiological recordings on single-channel level and did not find any differences. Next we examined channel surface expression in Xenopus oocytes and HeLa cells using a chemiluminescence assay and found the edited channels to be less readily expressed at the surface membrane. This reduction in surface expression was verified by fluorescence imaging experiments. Western blot analysis for comparison of protein abundances and glycosylation patterns did not show any difference between Kv1.1 and Kv1.1(I400V), further indicating that changed trafficking of Kv1.1(I400V) is causing the current reduction. Block of endocytosis by dynasore or AP180C did not abolish the differences in current amplitudes between Kv1.1 and Kv1.1(I400V), suggesting that backward trafficking is not affected. Therefore, our data suggest that I400V RNA editing of Kv1.1 leads to a reduced current size by a decreased forward trafficking of the channel to the surface membrane. This effect is specific for Kv1.1 because coexpression of Kv1.4 channel subunits with Kv1.1(I400V) abolishes these trafficking effects. Taken together, we identified RNA editing as a novel mechanism to regulate homomeric Kv1.1 channel trafficking. Fine-tuning of Kv1.1 surface expression by RNA editing might contribute to the complexity of neuronal Kv channel regulation.
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Affiliation(s)
- Anne K Streit
- Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Lina A Matschke
- Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Amalia M Dolga
- Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Susanne Rinné
- Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Niels Decher
- Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany.
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