1
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Furia F, Levy AM, Theunis M, Bamshad MJ, Bartos MN, Bijlsma EK, Brancati F, Cejudo L, Chong JX, De Luca C, Dean SJ, Egense A, Goel H, Guenzel AJ, Hüffmeier U, Legius E, Mancini GMS, Marcos-Alcalde I, Niclass T, Planes M, Redon S, Ros-Pardo D, Rouault K, Schot R, Schuhmann S, Shen JJ, Tao AM, Thiffault I, Van Esch H, Wentzensen IM, Barakat TS, Møller RS, Gomez-Puertas P, Chung WK, Gardella E, Tümer Z. The phenotypic and genotypic spectrum of individuals with mono- or biallelic ANK3 variants. Clin Genet 2024. [PMID: 38988293 DOI: 10.1111/cge.14587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/12/2024]
Abstract
ANK3 encodes ankyrin-G, a protein involved in neuronal development and signaling. Alternative splicing gives rise to three ankyrin-G isoforms comprising different domains with distinct expression patterns. Mono- or biallelic ANK3 variants are associated with non-specific syndromic intellectual disability in 14 individuals (seven with monoallelic and seven with biallelic variants). In this study, we describe the clinical features of 13 additional individuals and review the data on a total of 27 individuals (16 individuals with monoallelic and 11 with biallelic ANK3 variants) and demonstrate that the phenotype for biallelic variants is more severe. The phenotypic features include language delay (92%), autism spectrum disorder (76%), intellectual disability (78%), hypotonia (65%), motor delay (68%), attention deficit disorder (ADD) or attention deficit hyperactivity disorder (ADHD) (57%), sleep disturbances (50%), aggressivity/self-injury (37.5%), and epilepsy (35%). A notable phenotypic difference was presence of ataxia in three individuals with biallelic variants, but in none of the individuals with monoallelic variants. While the majority of the monoallelic variants are predicted to result in a truncated protein, biallelic variants are almost exclusively missense. Moreover, mono- and biallelic variants appear to be localized differently across the three different ankyrin-G isoforms, suggesting isoform-specific pathological mechanisms.
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Affiliation(s)
- Francesca Furia
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark
- Faculty of Health Science, University of Southern Denmark (SDU), Odense, Denmark
| | - Amanda M Levy
- Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Copenhagen, Denmark
| | - Miel Theunis
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Michael J Bamshad
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, Washington, USA
- Brotman-Baty Institute for Precision Medicine, University of Washington, Seattle, Washington, USA
- Department of Pediatrics, Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington, USA
| | - Meghan N Bartos
- Department of Genetics, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Francesco Brancati
- Human Genetics, Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
- Human Functional Genetics Laboratory, Istituto di Ricovero e Cura a Carattere Scientifico San Raffaele Roma, Rome, Italy
| | - Lucile Cejudo
- CHU de Poitiers, Service de Génétique, Poitiers, France
| | - Jessica X Chong
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, Washington, USA
- Brotman-Baty Institute for Precision Medicine, University of Washington, Seattle, Washington, USA
| | - Chiara De Luca
- Human Genetics, Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Sarah Joy Dean
- Department of Genetics, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Alena Egense
- Division of Genomic Medicine, Department of Pediatrics, University of California Davis, Sacramento, California, USA
| | - Himanshu Goel
- General Genetics Service, Hunter Genetics, Waratah, New South Wales, Australia
- School of Medicine and Public Health, College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, New South Wales, Australia
| | | | - Ulrike Hüffmeier
- Institute of Human Genetics, Universitätsklinikum Erlangen, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Eric Legius
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Iñigo Marcos-Alcalde
- Molecular Modeling Group, Centro de Biología Molecular Severo Ochoa (CBM, CSIC-UAM), Madrid, Spain
| | | | - Marc Planes
- Service de Génétique Clinique, CHRU de Brest, Brest, France
| | - Sylvia Redon
- Service de Génétique Médicale et Biologie de la Reproduction, CHU de Brest, Brest, France
- Université de Brest, INSERM, Etablissement Français du Sang, UMR 1078, Brest, France
| | - David Ros-Pardo
- Molecular Modeling Group, Centro de Biología Molecular Severo Ochoa (CBM, CSIC-UAM), Madrid, Spain
| | - Karen Rouault
- Service de Génétique Médicale et Biologie de la Reproduction, CHU de Brest, Brest, France
- Université de Brest, INSERM, Etablissement Français du Sang, UMR 1078, Brest, France
| | - Rachel Schot
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Sarah Schuhmann
- Institute of Human Genetics, Universitätsklinikum Erlangen, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Joseph J Shen
- Division of Genomic Medicine, Department of Pediatrics, University of California Davis, Sacramento, California, USA
| | - Alice M Tao
- Vagelos School of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Isabelle Thiffault
- Department of Pathology, Children's Mercy Kansas City, Kansas City, Missouri, USA
- Genomic Medicine Center, Children's Mercy Kansas City, Kansas City, Missouri, USA
| | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
- Laboratory for the Genetics of Cognition, KU Leuven, Leuven, Belgium
| | | | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark
- Faculty of Health Science, University of Southern Denmark (SDU), Odense, Denmark
| | - Paulino Gomez-Puertas
- Molecular Modeling Group, Centro de Biología Molecular Severo Ochoa (CBM, CSIC-UAM), Madrid, Spain
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark
- Faculty of Health Science, University of Southern Denmark (SDU), Odense, Denmark
- Department of Neurophysiology, The Danish Epilepsy Centre, Dianalund, Denmark
| | - Zeynep Tümer
- Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Han Y, Li M, Zhao B, Wang H, Liu Y, Liu Z, Xu J, Yang R. MARK2 phosphorylates KIF13A at a 14-3-3 binding site to polarize vesicular transport of transferrin receptor within dendrites. Proc Natl Acad Sci U S A 2024; 121:e2316266121. [PMID: 38709923 PMCID: PMC11098127 DOI: 10.1073/pnas.2316266121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 03/19/2024] [Indexed: 05/08/2024] Open
Abstract
Neurons regulate the microtubule-based transport of certain vesicles selectively into axons or dendrites to ensure proper polarization of function. The mechanism of this polarized vesicle transport is still not fully elucidated, though it is known to involve kinesins, which drive anterograde transport on microtubules. Here, we explore how the kinesin-3 family member KIF13A is regulated such that vesicles containing transferrin receptor (TfR) travel only to dendrites. In experiments involving live-cell imaging, knockout of KIF13A, BioID assay, we found that the kinase MARK2 phosphorylates KIF13A at a 14-3-3 binding motif, strengthening interaction of KIF13A with 14-3-3 such that it dissociates from TfR-containing vesicles, which therefore cannot enter axons. Overexpression of KIF13A or knockout of MARK2 leads to axonal transport of TfR-containing vesicles. These results suggest a unique kinesin-based mechanism for polarized transport of vesicles to dendrites.
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Affiliation(s)
- Yue Han
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Min Li
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Bingqing Zhao
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Huichao Wang
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Yan Liu
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Zhijun Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi Province710061, China
| | - Jiaxi Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
| | - Rui Yang
- Institute of Neuroscience, Translational Medicine Institute, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Health Science Center, Xi’an Jiaotong University, Xi’an710061, China
- The Jungers Center for Neurosciences Research, The Department of Neurology, Oregon Health & Science University, Portland, OR97239-3098
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Konietzny A, Han Y, Popp Y, van Bommel B, Sharma A, Delagrange P, Arbez N, Moutin MJ, Peris L, Mikhaylova M. Efficient axonal transport of endolysosomes relies on the balanced ratio of microtubule tyrosination and detyrosination. J Cell Sci 2024; 137:jcs261737. [PMID: 38525600 PMCID: PMC11112122 DOI: 10.1242/jcs.261737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 03/14/2024] [Indexed: 03/26/2024] Open
Abstract
In neurons, the microtubule (MT) cytoskeleton forms the basis for long-distance protein transport from the cell body into and out of dendrites and axons. To maintain neuronal polarity, the axon initial segment (AIS) serves as a physical barrier, separating the axon from the somatodendritic compartment and acting as a filter for axonal cargo. Selective trafficking is further instructed by axonal enrichment of MT post-translational modifications, which affect MT dynamics and the activity of motor proteins. Here, we compared two knockout mouse lines lacking the respective enzymes for MT tyrosination and detyrosination, and found that both knockouts led to a shortening of the AIS. Neurons from both lines also showed an increased immobile fraction of endolysosomes present in the axon, whereas mobile organelles displayed shortened run distances in the retrograde direction. Overall, our results highlight the importance of maintaining the balance of tyrosinated and detyrosinated MTs for proper AIS length and axonal transport processes.
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Affiliation(s)
- Anja Konietzny
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | - Yuhao Han
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Centre for Structural Systems Biology, Hamburg 22607, Germany
- Structural Cell Biology of Viruses, Leibniz Institute of Virology (LIV), Hamburg 20251, Germany
| | - Yannes Popp
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Charité – Universitätsmedizin Berlin, Einstein Center for Neurosciences Berlin, 10117 Berlin, Germany
| | - Bas van Bommel
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Aditi Sharma
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | | | - Nicolas Arbez
- Institut de Recherche Servier, Croissy 78290, France
| | - Marie-Jo Moutin
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Leticia Peris
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Marina Mikhaylova
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
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4
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Xu Z, Angstmann CN, Wu Y, Stefen H, Parić E, Fath T, Curmi PM. Location of the axon initial segment assembly can be predicted from neuronal shape. iScience 2024; 27:109264. [PMID: 38450155 PMCID: PMC10915628 DOI: 10.1016/j.isci.2024.109264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/21/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
The axon initial segment (AIS) is located at the proximal axon demarcating the boundary between axonal and somatodendritic compartments. The AIS facilitates the generation of action potentials and maintenance of neuronal polarity. In this study, we show that the location of AIS assembly, as marked by Ankyrin G, corresponds to the nodal plane of the lowest-order harmonic of the Laplace-Beltrami operator solved over the neuronal shape. This correlation establishes a coupling between location of AIS assembly and neuronal cell morphology. We validate this correlation for neurons with atypical morphology and neurons containing multiple AnkG clusters on distinct neurites, where the nodal plane selects the appropriate axon showing enriched Tau. Based on our findings, we propose that Turing patterning systems are candidates for dynamically governing AIS location. Overall, this study highlights the importance of neuronal cell morphology in determining the precise localization of the AIS within the proximal axon.
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Affiliation(s)
- Zhuang Xu
- School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Mathematics and Statistics, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Christopher N. Angstmann
- School of Mathematics and Statistics, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yuhuang Wu
- Infection Analytics Program, Kirby Institute for Infection and Immunity, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Holly Stefen
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Esmeralda Parić
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Thomas Fath
- Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Paul M.G. Curmi
- School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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Han Y, Li M, Zhao B, Wang H, Liu Y, Liu Z, Xu J, Yang R. MARK2 phosphorylates KIF13A at a 14-3-3 binding site to polarize vesicular transport of transferrin receptor within dendrites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.11.548513. [PMID: 38105964 PMCID: PMC10723257 DOI: 10.1101/2023.07.11.548513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Neurons regulate the microtubule-based transport of certain vesicles selectively into axons or dendrites to ensure proper polarization of function. The mechanism of this polarized vesicle transport is still not fully elucidated, though it is known to involve kinesins, which drive anterograde transport on microtubules. Here we explore how the kinesin-3 family member KIF13A is regulated such that vesicles containing transferrin receptor (TfR) travel only to dendrites. In experiments involving live-cell imaging, knockout of KIF13A, BioID assay, we found that the kinase MARK2 phosphorylates KIF13A at a 14-3-3 binding motif, strengthening interaction of KIF13A with 14-3-3 such that it dissociates from TfR-containing vesicles, which therefore cannot enter axons. Overexpression of KIF13A or knockout of MARK2 leads to axonal transport of TfR-containing vesicles. These results suggest a novel kinesin-based mechanism for polarized transport of vesicles to dendrites. Significance Our findings suggest that at least one type of vesicles, those containing transferrin receptor, travel exclusively to dendrites and are excluded from axons because the kinase MARK2 phosphorylates the kinesin KIF13A to promote its separation from vesicles at the proximal axon, preventing vesicle transport into axons, such that they travel only to dendrites. Future studies should explore how this mechanism of polarized vesicle transport supports neuronal function.
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Iwahashi M, Yoshimura T, Harigai W, Takuma K, Hashimoto H, Katayama T, Hayata-Takano A. Pituitary adenylate cyclase-activating polypeptide deficient mice show length abnormalities of the axon initial segment. J Pharmacol Sci 2023; 153:175-182. [PMID: 37770159 DOI: 10.1016/j.jphs.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/25/2023] [Indexed: 10/03/2023] Open
Abstract
We previously found that pituitary adenylate cyclase-activating polypeptide (PACAP)-deficient (PACAP-/-) mice exhibit dendritic spine morphology impairment and neurodevelopmental disorder (NDD)-like behaviors such as hyperactivity, increased novelty-seeking behavior, and deficient pre-pulse inhibition. Recent studies have indicated that rodent models of NDDs (e.g., attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder) show abnormalities in the axon initial segment (AIS). Here, we revealed that PACAP-/- mice exhibited a longer AIS length in layer 2/3 pyramidal neurons of the primary somatosensory barrel field compared with wild-type control mice. Further, we previously showed that a single injection of atomoxetine, an ADHD drug, improved hyperactivity in PACAP-/- mice. In this study, we found that repeated treatments of atomoxetine significantly improved AIS abnormality along with hyperactivity in PACAP-/- mice. These results suggest that AIS abnormalities are associated with NDDs-like behaviors in PACAP-/- mice. Thus, improvement in AIS abnormalities will be a novel drug therapy for NDDs.
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Affiliation(s)
- Misaki Iwahashi
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Wakana Harigai
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuhiro Takuma
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hitoshi Hashimoto
- Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan; Division of Bioscience, Institute for Datability Science, Osaka University, 2-8 Yamadaoka, Suita, Osaka, 565-0871, Japan; Department of Molecular Pharmaceutical Science, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuko Hayata-Takano
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan; Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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7
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Hu A, Zhao R, Ren B, Li Y, Lu J, Tai Y. Projection-Specific Heterogeneity of the Axon Initial Segment of Pyramidal Neurons in the Prelimbic Cortex. Neurosci Bull 2023; 39:1050-1068. [PMID: 36849716 PMCID: PMC10313623 DOI: 10.1007/s12264-023-01038-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/22/2022] [Indexed: 03/01/2023] Open
Abstract
The axon initial segment (AIS) is a highly specialized axonal compartment where the action potential is initiated. The heterogeneity of AISs has been suggested to occur between interneurons and pyramidal neurons (PyNs), which likely contributes to their unique spiking properties. However, whether the various characteristics of AISs can be linked to specific PyN subtypes remains unknown. Here, we report that in the prelimbic cortex (PL) of the mouse, two types of PyNs with axon projections either to the contralateral PL or to the ipsilateral basal lateral amygdala, possess distinct AIS properties reflected by morphology, ion channel expression, action potential initiation, and axo-axonic synaptic inputs from chandelier cells. Furthermore, projection-specific AIS diversity is more prominent in the superficial layer than in the deep layer. Thus, our study reveals the cortical layer- and axon projection-specific heterogeneity of PyN AISs, which may endow the spiking of various PyN types with exquisite modulation.
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Affiliation(s)
- Ankang Hu
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
- School of Clinical Medicine, Fudan University, Shanghai, 200032, China
| | - Rui Zhao
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Baihui Ren
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yang Li
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Jiangteng Lu
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai, 201210, China.
| | - Yilin Tai
- The State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, and the Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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8
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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9
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Lorenzo DN, Edwards RJ, Slavutsky AL. Spectrins: molecular organizers and targets of neurological disorders. Nat Rev Neurosci 2023; 24:195-212. [PMID: 36697767 PMCID: PMC10598481 DOI: 10.1038/s41583-022-00674-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/26/2023]
Abstract
Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anastasia L Slavutsky
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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10
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Murphy KE, Wade SD, Sperringer JE, Mohan V, Duncan BW, Zhang EY, Pak Y, Lutz D, Schachner M, Maness PF. The L1 cell adhesion molecule constrains dendritic spine density in pyramidal neurons of the mouse cerebral cortex. Front Neuroanat 2023; 17:1111525. [PMID: 37007644 PMCID: PMC10062527 DOI: 10.3389/fnana.2023.1111525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/24/2023] [Indexed: 03/18/2023] Open
Abstract
A novel function for the L1 cell adhesion molecule, which binds the actin adaptor protein Ankyrin was identified in constraining dendritic spine density on pyramidal neurons in the mouse neocortex. In an L1-null mouse mutant increased spine density was observed on apical but not basal dendrites of pyramidal neurons in diverse cortical areas (prefrontal cortex layer 2/3, motor cortex layer 5, visual cortex layer 4. The Ankyrin binding motif (FIGQY) in the L1 cytoplasmic domain was critical for spine regulation, as demonstrated by increased spine density and altered spine morphology in the prefrontal cortex of a mouse knock-in mutant (L1YH) harboring a tyrosine (Y) to histidine (H) mutation in the FIGQY motif, which disrupted L1-Ankyrin association. This mutation is a known variant in the human L1 syndrome of intellectual disability. L1 was localized by immunofluorescence staining to spine heads and dendrites of cortical pyramidal neurons. L1 coimmunoprecipitated with Ankyrin B (220 kDa isoform) from lysates of wild type but not L1YH forebrain. This study provides insight into the molecular mechanism of spine regulation and underscores the potential for this adhesion molecule to regulate cognitive and other L1-related functions that are abnormal in the L1 syndrome.
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Affiliation(s)
- Kelsey E. Murphy
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah D. Wade
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Justin E. Sperringer
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Vishwa Mohan
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Bryce W. Duncan
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Erin Y. Zhang
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - Yubin Pak
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
| | - David Lutz
- Division of Neuroanatomy and Molecular Brain Research, Ruhr University-Bochum, Bochum, Germany
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscatawy, NJ, United States
| | - Patricia F. Maness
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- Carolina Institute of Developmental Disabilities, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, NC, United States
- *Correspondence: Patricia F. Maness
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11
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Impaired OTUD7A-dependent Ankyrin regulation mediates neuronal dysfunction in mouse and human models of the 15q13.3 microdeletion syndrome. Mol Psychiatry 2023; 28:1747-1769. [PMID: 36604605 DOI: 10.1038/s41380-022-01937-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023]
Abstract
Copy number variations (CNVs) are associated with psychiatric and neurodevelopmental disorders (NDDs), and most, including the recurrent 15q13.3 microdeletion disorder, have unknown disease mechanisms. We used a heterozygous 15q13.3 microdeletion mouse model and patient iPSC-derived neurons to reveal developmental defects in neuronal maturation and network activity. To identify the underlying molecular dysfunction, we developed a neuron-specific proximity-labeling proteomics (BioID2) pipeline, combined with patient mutations, to target the 15q13.3 CNV genetic driver OTUD7A. OTUD7A is an emerging independent NDD risk gene with no known function in the brain, but has putative deubiquitinase function. The OTUD7A protein-protein interaction network included synaptic, axonal, and cytoskeletal proteins and was enriched for ASD and epilepsy risk genes (Ank3, Ank2, SPTAN1, SPTBN1). The interactions between OTUD7A and Ankyrin-G (Ank3) and Ankyrin-B (Ank2) were disrupted by an epilepsy-associated OTUD7A L233F variant. Further investigation of Ankyrin-G in mouse and human 15q13.3 microdeletion and OTUD7AL233F/L233F models revealed protein instability, increased polyubiquitination, and decreased levels in the axon initial segment, while structured illumination microscopy identified reduced Ankyrin-G nanodomains in dendritic spines. Functional analysis of human 15q13.3 microdeletion and OTUD7AL233F/L233F models revealed shared and distinct impairments to axonal growth and intrinsic excitability. Importantly, restoring OTUD7A or Ankyrin-G expression in 15q13.3 microdeletion neurons led to a reversal of abnormalities. These data reveal a critical OTUD7A-Ankyrin pathway in neuronal development, which is impaired in the 15q13.3 microdeletion syndrome, leading to neuronal dysfunction. Furthermore, our study highlights the utility of targeting CNV genes using cell type-specific proteomics to identify shared and unexplored disease mechanisms across NDDs.
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12
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Baculis BC, Kesavan H, Weiss AC, Kim EH, Tracy GC, Ouyang W, Tsai NP, Chung HJ. Homeostatic regulation of extracellular signal-regulated kinase 1/2 activity and axonal K v7.3 expression by prolonged blockade of hippocampal neuronal activity. Front Cell Neurosci 2022; 16:838419. [PMID: 35966206 PMCID: PMC9366003 DOI: 10.3389/fncel.2022.838419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Homeostatic plasticity encompasses the mechanisms by which neurons stabilize their synaptic strength and excitability in response to prolonged and destabilizing changes in their network activity. Prolonged activity blockade leads to homeostatic scaling of action potential (AP) firing rate in hippocampal neurons in part by decreased activity of N-Methyl-D-Aspartate receptors and subsequent transcriptional down-regulation of potassium channel genes including KCNQ3 which encodes Kv7.3. Neuronal Kv7 channels are mostly heterotetramers of Kv7.2 and Kv7.3 subunits and are highly enriched at the axon initial segment (AIS) where their current potently inhibits repetitive and burst firing of APs. However, whether a decrease in Kv7.3 expression occurs at the AIS during homeostatic scaling of intrinsic excitability and what signaling pathway reduces KCNQ3 transcript upon prolonged activity blockade remain unknown. Here, we report that prolonged activity blockade in cultured hippocampal neurons reduces the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) followed by a decrease in the activation of brain-derived neurotrophic factor (BDNF) receptor, Tropomyosin receptor kinase B (TrkB). Furthermore, both prolonged activity blockade and prolonged pharmacological inhibition of ERK1/2 decrease KCNQ3 and BDNF transcripts as well as the density of Kv7.3 and ankyrin-G at the AIS. Collectively, our findings suggest that a reduction in the ERK1/2 activity and subsequent transcriptional down-regulation may serve as a potential signaling pathway that links prolonged activity blockade to homeostatic control of BDNF-TrkB signaling and Kv7.3 density at the AIS during homeostatic scaling of AP firing rate.
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Affiliation(s)
- Brian C. Baculis
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Harish Kesavan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Amanda C. Weiss
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Edward H. Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Gregory C. Tracy
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Wenhao Ouyang
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Nien-Pei Tsai
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Hee Jung Chung
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
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13
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Eichel K, Shen K. The function of the axon initial segment in neuronal polarity. Dev Biol 2022; 489:47-54. [DOI: 10.1016/j.ydbio.2022.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/09/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022]
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14
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Owen N, Toms M, Young RM, Eintracht J, Sarkar H, Brooks BP, Moosajee M. Identification of 4 novel human ocular coloboma genes ANK3, BMPR1B, PDGFRA, and CDH4 through evolutionary conserved vertebrate gene analysis. Genet Med 2022; 24:1073-1084. [PMID: 35034853 DOI: 10.1016/j.gim.2021.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Ocular coloboma arises from genetic or environmental perturbations that inhibit optic fissure (OF) fusion during early eye development. Despite high genetic heterogeneity, 70% to 85% of patients remain molecularly undiagnosed. In this study, we have identified new potential causative genes using cross-species comparative meta-analysis. METHODS Evolutionarily conserved differentially expressed genes were identified through in silico analysis, with in situ hybridization, gene knockdown, and rescue performed to confirm spatiotemporal gene expression and phenotype. Interrogation of the 100,000 Genomes Project for putative pathogenic variants was performed. RESULTS Nine conserved differentially expressed genes between zebrafish and mouse were identified. Expression of zebrafish ank3a, bmpr1ba/b, cdh4, and pdgfaa was localized to the OF, periocular mesenchyme cells, or ciliary marginal zone, regions traversed by the OF. Knockdown of ank3, bmpr1b, and pdgfaa revealed a coloboma and/or microphthalmia phenotype. Novel pathogenic variants in ANK3, BMPR1B, PDGFRA, and CDH4 were identified in 8 unrelated coloboma families. We showed BMPR1B rescued the knockdown phenotype but variant messenger RNAs failed, providing evidence of pathogenicity. CONCLUSION We show the utility of cross-species meta-analysis to identify several novel coloboma disease-causing genes. There is a potential to increase the diagnostic yield for new and unsolved patients while adding to our understanding of the genetic basis of OF morphogenesis.
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Affiliation(s)
- Nicholas Owen
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Rodrigo M Young
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Jonathan Eintracht
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Hajrah Sarkar
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom; Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom; Ocular Genomics and Therapeutics, The Francis Crick Institute, London, United Kingdom.
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15
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Usui N, Tian X, Harigai W, Togawa S, Utsunomiya R, Doi T, Miyoshi K, Shinoda K, Tanaka J, Shimada S, Katayama T, Yoshimura T. Length impairments of the axon initial segment in rodent models of attention-deficit hyperactivity disorder and autism spectrum disorder. Neurochem Int 2021; 153:105273. [PMID: 34971749 DOI: 10.1016/j.neuint.2021.105273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 11/25/2022]
Abstract
The axon initial segment (AIS) is a structural neuronal compartment of the proximal axon that plays key roles in sodium channel clustering, action potential initiation, and signal propagation of neuronal outputs. Mutations in constitutive genes of the AIS, such as ANK3, have been identified in patients with neurodevelopmental disorders. Nevertheless, morphological changes in the AIS in neurodevelopmental disorders have not been characterized. In this study, we investigated the length of the AIS in rodent models of attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). We observed abnormalities in AIS length in both animal models. In ADHD model rodents, we observed shorter AIS length in layer 2/3 (L2/3) neurons of the medial prefrontal cortex (mPFC) and primary somatosensory barrel field (S1BF). Further, we observed shorter AIS length in S1BF L5 neurons. In ASD model mice, we observed shorter AIS length in L2/3 and L5 neurons of the S1BF. These results suggest that impairments in AIS length are common phenomena in neurodevelopmental disorders such as ADHD and ASD and may be conserved across species. Our findings provide novel insight into the potential contribution of the AIS to the pathophysiology and pathogenesis of neurodevelopmental disorders.
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Affiliation(s)
- Noriyoshi Usui
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, 565-0871, Japan; United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan; Global Center for Medical Engineering and Informatics, Osaka University, Suita, 565-0871, Japan; Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Hirakata, 573-0022, Japan.
| | - Xiaoye Tian
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan
| | - Wakana Harigai
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan
| | - Shogo Togawa
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, 565-0871, Japan; Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Yamaguchi, 755-8505, Japan
| | - Ryo Utsunomiya
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan
| | - Tomomi Doi
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan
| | - Ko Miyoshi
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan
| | - Koh Shinoda
- Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Yamaguchi, 755-8505, Japan
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, 565-0871, Japan; United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan; Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Hirakata, 573-0022, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, 565-0871, Japan.
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16
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The largest isoform of Ankyrin-G is required for lattice structure of the axon initial segment. Biochem Biophys Res Commun 2021; 578:28-34. [PMID: 34534742 DOI: 10.1016/j.bbrc.2021.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/18/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022]
Abstract
Alzheimer's disease (AD) is the most frequent neurodegenerative disease and a common dementia in elderly individuals. Previous studies found a strong correlation between axon initial segment (AIS) defects and AD, but it remains unclear whether AD itself changes the arrangement of AIS components, and the mechanisms by which adaptor proteins and ion channels in the AIS are disturbed in AD are not well understood. With super-resolution structured illumination microscopy (SIM) revealing axonal structures, here we imaged the lattice structure of completely assembled AIS in APP/PS1 neurons. By analyzing the images with Gaussian fitting and 1D mean autocorrelation, we found dual spacings (∼200 nm and ∼370 nm) of Ankyrin-G (AnkG), Nav1.2 and βIV-spectrin in AD model APP/PS1 mice due to the low-expressed 480-kDa AnkG. To identify the roles of each AnkG isoform, two isoforms were separately expressed in neurons from AnkG conditional knockout mice. Mice rescued with 270-kDa AnkG displayed dual spacings of AnkG components in cultured neurons and impaired in spatial memory, while transgenic mice expressing 480-kDa AnkG showed a normal molecular distribution in the AIS and normal cognitive performance. Our findings provide new insight into the mechanisms underlying impaired cognition associated with neurodegenerative diseases such as AD.
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17
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Fujitani M, Otani Y, Miyajima H. Pathophysiological Roles of Abnormal Axon Initial Segments in Neurodevelopmental Disorders. Cells 2021; 10:2110. [PMID: 34440880 PMCID: PMC8392614 DOI: 10.3390/cells10082110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 11/17/2022] Open
Abstract
The 20-60 μm axon initial segment (AIS) is proximally located at the interface between the axon and cell body. AIS has characteristic molecular and structural properties regulated by the crucial protein, ankyrin-G. The AIS contains a high density of Na+ channels relative to the cell body, which allows low thresholds for the initiation of action potential (AP). Molecular and physiological studies have shown that the AIS is also a key domain for the control of neuronal excitability by homeostatic mechanisms. The AIS has high plasticity in normal developmental processes and pathological activities, such as injury, neurodegeneration, and neurodevelopmental disorders (NDDs). In the first half of this review, we provide an overview of the molecular, structural, and ion-channel characteristics of AIS, AIS regulation through axo-axonic synapses, and axo-glial interactions. In the second half, to understand the relationship between NDDs and AIS, we discuss the activity-dependent plasticity of AIS, the human mutation of AIS regulatory genes, and the pathophysiological role of an abnormal AIS in NDD model animals and patients. We propose that the AIS may provide a potentially valuable structural biomarker in response to abnormal network activity in vivo as well as a new treatment concept at the neural circuit level.
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Affiliation(s)
- Masashi Fujitani
- Department of Anatomy and Neuroscience, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-shi 693-8501, Shimane, Japan; (Y.O.); (H.M.)
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18
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Cordner ZA, Khambadkone SG, Zhu S, Bai J, Forti RR, Goodman E, Tamashiro KL, Ross CA. Ankyrin-G Heterozygous Knockout Mice Display Increased Sensitivity to Social Defeat Stress. Complex Psychiatry 2021; 7:71-79. [DOI: 10.1159/000518819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 07/30/2021] [Indexed: 11/19/2022] Open
Abstract
The <i>ANK3</i> locus has been repeatedly found to confer an increased risk for bipolar disorder. <i>ANK3</i> codes for Ankyrin-G (Ank-G), a scaffold protein concentrated at axon initial segments, nodes of Ranvier, and dendritic spines, where it organizes voltage-gated sodium and potassium channels and cytoskeletal proteins. Mice with homozygous conditional knockout of Ank-G in the adult forebrain display hyperactivity and reduced anxiety-like behaviors, responsive to mood stabilizers. Their behavior switches to a depression-like phenotype when exposed to chronic social defeat stress (SDS), and then spontaneously reverts to baseline hyperactivity. Ank-G heterozygous conditional knockouts (Ank-G Het cKO) have not previously been characterized. Here, we describe the behavior of Ank-G Het cKO mice compared to littermate controls in the open field, elevated plus maze, and forced swim test, under both unstressed and stressed conditions. We found that Ank-G Het cKO is not significantly different from controls at baseline or after chronic SDS. The chronic stress-induced “depression-like” behavioral phenotype is persistent for at least 28 days and is responsive to fluoxetine. Strikingly, Ank-G Het cKO mice display increased sensitivity to a short duration SDS, which does not affect controls. The heterozygous Ank-G genetic model may provide novel insights into the role of Ank-G in the pathophysiology of stress sensitivity and “depression-like” phenotypes and could be useful for studying Ank-G-related gene-environment interactions.
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19
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Quistgaard EM, Nissen JD, Hansen S, Nissen P. Mind the Gap: Molecular Architecture of the Axon Initial Segment - From Fold Prediction to a Mechanistic Model of Function? J Mol Biol 2021; 433:167176. [PMID: 34303720 DOI: 10.1016/j.jmb.2021.167176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 11/28/2022]
Abstract
The axon initial segment (AIS) is a distinct neuronal domain, which is responsible for initiating action potentials, and therefore of key importance to neuronal signaling. To determine how it functions, it is necessary to establish which proteins reside there, how they are organized, and what the dynamic features are. Great strides have been made in recent years, and it is now clear that several AIS cytoskeletal and membrane proteins interact to form a higher-order periodic structure. Here we briefly describe AIS function, protein composition and molecular architecture, and discuss perspectives for future structural characterization, and if structure predictions will be able to model complex higher-order assemblies.
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Affiliation(s)
- Esben M Quistgaard
- DANDRITE - Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Dept. Molecular Biology and Genetics, DK - 8000 Aarhus C, Denmark
| | - Josephine Dannersø Nissen
- DANDRITE - Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Dept. Molecular Biology and Genetics, DK - 8000 Aarhus C, Denmark
| | - Sean Hansen
- DANDRITE - Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Dept. Molecular Biology and Genetics, DK - 8000 Aarhus C, Denmark
| | - Poul Nissen
- DANDRITE - Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Dept. Molecular Biology and Genetics, DK - 8000 Aarhus C, Denmark.
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20
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ANK3 related neurodevelopmental disorders: expanding the spectrum of heterozygous loss-of-function variants. Neurogenetics 2021; 22:263-269. [PMID: 34218362 PMCID: PMC8426245 DOI: 10.1007/s10048-021-00655-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 06/20/2021] [Indexed: 11/03/2022]
Abstract
ANK3 encodes multiple isoforms of ankyrin-G, resulting in variegated tissue expression and function, especially regarding its role in neuronal development. Based on the zygosity, location, and type, ANK3 variants result in different neurodevelopmental phenotypes. Autism spectrum disorder has been associated with heterozygous missense variants in ANK3, whereas a more severe neurodevelopmental phenotype is caused by isoform-dependent, autosomal-dominant, or autosomal-recessive loss-of-function variants. Here, we present four individuals affected by a variable neurodevelopmental phenotype harboring a heterozygous frameshift or nonsense variant affecting all ANK3 transcripts. Thus, we provide further evidence of an isoform-based phenotypic continuum underlying ANK3-associated pathologies and expand its phenotypic spectrum.
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21
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Di Re J, Hsu WCJ, Kayasandik CB, Fularczyk N, James TF, Nenov MN, Negi P, Marosi M, Scala F, Prasad S, Labate D, Laezza F. Inhibition of AKT Signaling Alters βIV Spectrin Distribution at the AIS and Increases Neuronal Excitability. Front Mol Neurosci 2021; 14:643860. [PMID: 34276302 PMCID: PMC8278006 DOI: 10.3389/fnmol.2021.643860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 05/27/2021] [Indexed: 11/24/2022] Open
Abstract
The axon initial segment (AIS) is a highly regulated subcellular domain required for neuronal firing. Changes in the AIS protein composition and distribution are a form of structural plasticity, which powerfully regulates neuronal activity and may underlie several neuropsychiatric and neurodegenerative disorders. Despite its physiological and pathophysiological relevance, the signaling pathways mediating AIS protein distribution are still poorly studied. Here, we used confocal imaging and whole-cell patch clamp electrophysiology in primary hippocampal neurons to study how AIS protein composition and neuronal firing varied in response to selected kinase inhibitors targeting the AKT/GSK3 pathway, which has previously been shown to phosphorylate AIS proteins. Image-based features representing the cellular pattern distribution of the voltage-gated Na+ (Nav) channel, ankyrin G, βIV spectrin, and the cell-adhesion molecule neurofascin were analyzed, revealing βIV spectrin as the most sensitive AIS protein to AKT/GSK3 pathway inhibition. Within this pathway, inhibition of AKT by triciribine has the greatest effect on βIV spectrin localization to the AIS and its subcellular distribution within neurons, a phenotype that Support Vector Machine classification was able to accurately distinguish from control. Treatment with triciribine also resulted in increased excitability in primary hippocampal neurons. Thus, perturbations to signaling mechanisms within the AKT pathway contribute to changes in βIV spectrin distribution and neuronal firing that may be associated with neuropsychiatric and neurodegenerative disorders.
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Affiliation(s)
- Jessica Di Re
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Wei-Chun J. Hsu
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
- Biochemistry and Molecular Biology Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, Galveston, TX, United States
- M.D./Ph.D. Combined Degree Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, Galveston, TX, United States
| | - Cihan B. Kayasandik
- Department of Mathematics, University of Houston, Houston, TX, United States
- Department of Computer Engineering, Istanbul Medipol University, Istanbul, Turkey
| | - Nickolas Fularczyk
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - T. F. James
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Miroslav N. Nenov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Pooran Negi
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - Mate Marosi
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Federico Scala
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Saurabh Prasad
- Department of Electrical and Computer Engineering, University of Houston, Houston, TX, United States
| | - Demetrio Labate
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
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22
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Cavus O, Williams J, Musa H, El Refaey M, Gratz D, Shaheen R, Schwieterman NA, Koenig S, Antwi-Boasiako S, Young LJ, Xu X, Han M, Wold LE, Hund TJ, Mohler PJ, Bradley EA. Giant ankyrin-G regulates cardiac function. J Biol Chem 2021; 296:100507. [PMID: 33675749 PMCID: PMC8040283 DOI: 10.1016/j.jbc.2021.100507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 11/30/2022] Open
Abstract
Cardiovascular disease (CVD) remains the most common cause of adult morbidity and mortality in developed nations. As a result, predisposition for CVD is increasingly important to understand. Ankyrins are intracellular proteins required for the maintenance of membrane domains. Canonical ankyrin-G (AnkG) has been shown to be vital for normal cardiac function, specifically cardiac excitability, via targeting and regulation of the cardiac voltage-gated sodium channel. Noncanonical (giant) AnkG isoforms play a key role in neuronal membrane biogenesis and excitability, with evidence for human neurologic disease when aberrant. However, the role of giant AnkG in cardiovascular tissue has yet to be explored. Here, we identify giant AnkG in the myocardium and identify that it is enriched in 1-week-old mice. Using a new mouse model lacking giant AnkG expression in myocytes, we identify that young mice displayed a dilated cardiomyopathy phenotype with aberrant electrical conduction and enhanced arrhythmogenicity. Structural and electrical dysfunction occurred at 1 week of age, when giant AnkG was highly expressed and did not appreciably change in adulthood until advanced age. At a cellular level, loss of giant AnkG results in delayed and early afterdepolarizations. However, surprisingly, giant AnkG cKO myocytes display normal INa, but abnormal myocyte contractility, suggesting unique roles of the large isoform in the heart. Finally, transcript analysis provided evidence for unique pathways that may contribute to the structural and electrical findings shown in giant AnkG cKO animals. In summary, we identify a critical role for giant AnkG that adds to the diversity of ankyrin function in the heart.
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Affiliation(s)
- Omer Cavus
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jordan Williams
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Hassan Musa
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Mona El Refaey
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Dan Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Rebecca Shaheen
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Neill A Schwieterman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Sara Koenig
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Steve Antwi-Boasiako
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Lindsay J Young
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Xianyao Xu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Mei Han
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Loren E Wold
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Elisa A Bradley
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA.
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23
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Stevens SR, Rasband MN. Ankyrins and neurological disease. Curr Opin Neurobiol 2021; 69:51-57. [PMID: 33485190 DOI: 10.1016/j.conb.2021.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 12/11/2022]
Abstract
Ankyrins are scaffolding proteins widely expressed throughout the nervous system. Ankyrins recruit diverse membrane proteins, including ion channels and cell adhesion molecules, into specialized subcellular membrane domains. These domains are stabilized by ankyrins interacting with the spectrin cytoskeleton. Ankyrin genes are highly associated with a number of neurological disorders, including Alzheimer's disease, schizophrenia, autism spectrum disorders, and bipolar disorder. Here, we discuss ankyrin function and their role in neurological disease. We propose mutations in ankyrins contribute to disease through two primary mechanisms: 1) altered neuronal excitability by disrupting ion channel clustering at key excitable domains, and 2) altered neuronal connectivity via impaired stabilization of membrane proteins.
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Affiliation(s)
- Sharon R Stevens
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
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24
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Ji B, Skup M. Roles of palmitoylation in structural long-term synaptic plasticity. Mol Brain 2021; 14:8. [PMID: 33430908 PMCID: PMC7802216 DOI: 10.1186/s13041-020-00717-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/15/2020] [Indexed: 11/30/2022] Open
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are important cellular mechanisms underlying learning and memory processes. N-Methyl-d-aspartate receptor (NMDAR)-dependent LTP and LTD play especially crucial roles in these functions, and their expression depends on changes in the number and single channel conductance of the major ionotropic glutamate receptor α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) located on the postsynaptic membrane. Structural changes in dendritic spines comprise the morphological platform and support for molecular changes in the execution of synaptic plasticity and memory storage. At the molecular level, spine morphology is directly determined by actin cytoskeleton organization within the spine and indirectly stabilized and consolidated by scaffold proteins at the spine head. Palmitoylation, as a uniquely reversible lipid modification with the ability to regulate protein membrane localization and trafficking, plays significant roles in the structural and functional regulation of LTP and LTD. Altered structural plasticity of dendritic spines is also considered a hallmark of neurodevelopmental disorders, while genetic evidence strongly links abnormal brain function to impaired palmitoylation. Numerous studies have indicated that palmitoylation contributes to morphological spine modifications. In this review, we have gathered data showing that the regulatory proteins that modulate the actin network and scaffold proteins related to AMPAR-mediated neurotransmission also undergo palmitoylation and play roles in modifying spine architecture during structural plasticity.
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Affiliation(s)
- Benjun Ji
- Nencki Institute of Experimental Biology, 02-093, Warsaw, Poland.
| | - Małgorzata Skup
- Nencki Institute of Experimental Biology, 02-093, Warsaw, Poland.
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25
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Solé L, Tamkun MM. Trafficking mechanisms underlying Na v channel subcellular localization in neurons. Channels (Austin) 2020; 14:1-17. [PMID: 31841065 PMCID: PMC7039628 DOI: 10.1080/19336950.2019.1700082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 11/13/2019] [Indexed: 01/06/2023] Open
Abstract
Voltage gated sodium channels (Nav) play a crucial role in action potential initiation and propagation. Although the discovery of Nav channels dates back more than 65 years, and great advances in understanding their localization, biophysical properties, and links to disease have been made, there are still many questions to be answered regarding the cellular and molecular mechanisms involved in Nav channel trafficking, localization and regulation. This review summarizes the different trafficking mechanisms underlying the polarized Nav channel localization in neurons, with an emphasis on the axon initial segment (AIS), as well as discussing the latest advances regarding how neurons regulate their excitability by modifying AIS length and location. The importance of Nav channel localization is emphasized by the relationship between mutations, impaired trafficking and disease. While this review focuses on Nav1.6, other Nav isoforms are also discussed.
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Affiliation(s)
- Laura Solé
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO, USA
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Michael M. Tamkun
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO, USA
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
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26
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Ni H, Ding H, Tao J, Wang Y, Tao M, Huang L. [Effects of olfactory deprivation on action potential and ankyrin-G expression in glutamatergic neurons in the barrel cortex of mice]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2020; 40:262-267. [PMID: 32376530 DOI: 10.12122/j.issn.1673-4254.2020.02.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate effect of upregulated touch sensation induced by olfactory deprivation on action potentials and ankyrin-G expression in the glutamatergic neurons in the barrel cortex of mice. METHODS Chloroform (40 μL) was dropped into the unilateral nasal cavity to induce olfactory deprivation in 40 C57 mice (12 days old), whose glutamatergic neurons were genetically labeled with yellow fluorescent protein (YFP). Behavioral experiments were carried out to assess the effects of olfactory deprivation on whisker tactile of the mice. The action potentials of the glutamatergic neurons in the barrel cortex on the side with or without chloroform treatment (olfactory deprivation group and control group, respectively) were recorded by patch-clamp electrophysiological recording, and ankyrin-G expression in the proximal axonal segment of the neurons was detected with immunohistochemistry. RESULTS Compared with those on the control side, the inter-spike intervals of the barrel glutamatergic neurons were significantly decreased and the absolute refractory periods were significantly shortened on the side with olfactory deprivation (P < 0.01); the expression of ankyrin-G was also significantly increased in the proximal axonal segment of the glutamatergic neurons in the barrel cortex on the side with olfactory deprivation (P < 0.01). CONCLUSIONS Olfaction deprivation induces up-regulation of touch sensation in mice possibly as a result of functional enhancement of the glutamatergic neurons and increased ankyrin-G expression in the barrel cortex.
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Affiliation(s)
- Hong Ni
- Department of Functional Experiment Center, Bengbu Medical College, Bengbu 233030, China
| | - Haihu Ding
- Department of Functional Experiment Center, Bengbu Medical College, Bengbu 233030, China
| | - Jing Tao
- Department of Functional Experiment Center, Bengbu Medical College, Bengbu 233030, China
| | - Yuanyuan Wang
- Department of Functional Experiment Center, Bengbu Medical College, Bengbu 233030, China
| | - Mingfei Tao
- Department of Functional Experiment Center, Bengbu Medical College, Bengbu 233030, China
| | - Li Huang
- Department of Pathophysiology, Bengbu Medical College, Bengbu 233030, China
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27
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Lorenzo DN. Cargo hold and delivery: Ankyrins, spectrins, and their functional patterning of neurons. Cytoskeleton (Hoboken) 2020; 77:129-148. [PMID: 32034889 DOI: 10.1002/cm.21602] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 01/12/2023]
Abstract
The highly polarized, typically very long, and nonmitotic nature of neurons present them with unique challenges in the maintenance of their homeostasis. This architectural complexity serves a rich and tightly controlled set of functions that enables their fast communication with neighboring cells and endows them with exquisite plasticity. The submembrane neuronal cytoskeleton occupies a pivotal position in orchestrating the structural patterning that determines local and long-range subcellular specialization, membrane dynamics, and a wide range of signaling events. At its center is the partnership between ankyrins and spectrins, which self-assemble with both remarkable long-range regularity and micro- and nanoscale specificity to precisely position and stabilize cell adhesion molecules, membrane transporters, ion channels, and other cytoskeletal proteins. To accomplish these generally conserved, but often functionally divergent and spatially diverse, roles these partners use a combinatorial program of a couple of dozens interacting family members, whose code is not fully unraveled. In a departure from their scaffolding roles, ankyrins and spectrins also enable the delivery of material to the plasma membrane by facilitating intracellular transport. Thus, it is unsurprising that deficits in ankyrins and spectrins underlie several neurodevelopmental, neurodegenerative, and psychiatric disorders. Here, I summarize key aspects of the biology of spectrins and ankyrins in the mammalian neuron and provide a snapshot of the latest advances in decoding their roles in the nervous system.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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28
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Mechanistic insights into the interactions of dynein regulator Ndel1 with neuronal ankyrins and implications in polarity maintenance. Proc Natl Acad Sci U S A 2019; 117:1207-1215. [PMID: 31889000 DOI: 10.1073/pnas.1916987117] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ankyrin-G (AnkG), a highly enriched scaffold protein in the axon initial segment (AIS) of neurons, functions to maintain axonal polarity and the integrity of the AIS. At the AIS, AnkG regulates selective intracellular cargo trafficking between soma and axons via interaction with the dynein regulator protein Ndel1, but the molecular mechanism underlying this binding remains elusive. Here we report that Ndel1's C-terminal coiled-coil region (CT-CC) binds to giant neuron-specific insertion regions present in both AnkG and AnkB with 2:1 stoichiometry. The high-resolution crystal structure of AnkB in complex with Ndel1 CT-CC revealed the detailed molecular basis governing the AnkB/Ndel1 complex formation. Mechanistically, AnkB binds with Ndel1 by forming a stable 5-helix bundle dominated by hydrophobic interactions spread across 6 distinct interaction layers. Moreover, we found that AnkG is essential for Ndel1 accumulation at the AIS. Finally, we found that cargo sorting at the AIS can be disrupted by blocking the AnkG/Ndel1 complex formation using a peptide designed based on our structural data. Collectively, the atomic structure of the AnkB/Ndel1 complex together with studies of cargo sorting through the AIS establish the mechanistic basis for AnkG/Ndel1 complex formation and for the maintenance of axonal polarity. Our study will also be valuable for future studies of the interaction between AnkB and Ndel1 perhaps at distal axonal cargo transport.
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