1
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Busby L, Serrano Nájera G, Steventon BJ. Intrinsic and extrinsic cues time somite progenitor contribution to the vertebrate primary body axis. eLife 2024; 13:e90499. [PMID: 38193440 PMCID: PMC10834026 DOI: 10.7554/elife.90499] [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: 06/26/2023] [Accepted: 01/08/2024] [Indexed: 01/10/2024] Open
Abstract
During embryonic development, the timing of events at the cellular level must be coordinated across multiple length scales to ensure the formation of a well-proportioned body plan. This is clear during somitogenesis, where progenitors must be allocated to the axis over time whilst maintaining a progenitor population for continued elaboration of the body plan. However, the relative importance of intrinsic and extrinsic signals in timing progenitor addition at the single-cell level is not yet understood. Heterochronic grafts from older to younger embryos have suggested a level of intrinsic timing whereby later staged cells contribute to more posterior portions of the axis. To determine the precise step at which cells are delayed, we performed single-cell transcriptomic analysis on heterochronic grafts of somite progenitors in the chicken embryo. This revealed a previously undescribed cell state within which heterochronic grafted cells are stalled. The delayed exit of older cells from this state correlates with expression of posterior Hox genes. Using grafting and explant culture, we find that both Hox gene expression and the migratory capabilities of progenitor populations are intrinsically regulated at the population level. However, by grafting varied sizes of tissue, we find that small heterochronic grafts disperse more readily and contribute to more anterior portions of the body axis while still maintaining Hox gene expression. This enhanced dispersion is not replicated in explant culture, suggesting that it is a consequence of interaction between host and donor tissue and thus extrinsic to the donor tissue. Therefore, we demonstrate that the timing of cell dispersion and resulting axis contribution is impacted by a combination of both intrinsic and extrinsic cues.
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Affiliation(s)
- Lara Busby
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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2
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Cabej NR. On the origin and nature of nongenetic information in eumetazoans. Ann N Y Acad Sci 2023. [PMID: 37154677 DOI: 10.1111/nyas.15001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nongenetic information implies all the forms of biological information not related to genes and DNA in general. Despite the deep scientific relevance of the concept, we currently lack reliable knowledge about its carriers and origins; hence, we still do not understand its true nature. Given that genes are the targets of nongenetic information, it appears that a parsimonious approach to find the ultimate source of that information is to trace back the sequential steps of the causal chain upstream of the target genes up to the ultimate link as the source of the nongenetic information. From this perspective, I examine seven nongenetically determined phenomena: placement of locus-specific epigenetic marks on DNA and histones, changes in snRNA expression patterns, neural induction of gene expression, site-specific alternative gene splicing, predator-induced morphological changes, and cultural inheritance. Based on the available evidence, I propose a general model of the common neural origin of all these forms of nongenetic information in eumetazoans.
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Affiliation(s)
- Nelson R Cabej
- Department of Biology, University of Tirana, Tirana, Albania
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3
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Chataigner LMP, Gogou C, den Boer MA, Frias CP, Thies-Weesie DME, Granneman JCM, Heck AJR, Meijer DH, Janssen BJC. Structural insights into the contactin 1 - neurofascin 155 adhesion complex. Nat Commun 2022; 13:6607. [PMID: 36329006 PMCID: PMC9633819 DOI: 10.1038/s41467-022-34302-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
Cell-surface expressed contactin 1 and neurofascin 155 control wiring of the nervous system and interact across cells to form and maintain paranodal myelin-axon junctions. The molecular mechanism of contactin 1 - neurofascin 155 adhesion complex formation is unresolved. Crystallographic structures of complexed and individual contactin 1 and neurofascin 155 binding regions presented here, provide a rich picture of how competing and complementary interfaces, post-translational glycosylation, splice differences and structural plasticity enable formation of diverse adhesion sites. Structural, biophysical, and cell-clustering analysis reveal how conserved Ig1-2 interfaces form competing heterophilic contactin 1 - neurofascin 155 and homophilic neurofascin 155 complexes whereas contactin 1 forms low-affinity clusters through interfaces on Ig3-6. The structures explain how the heterophilic Ig1-Ig4 horseshoe's in the contactin 1 - neurofascin 155 complex define the 7.4 nm paranodal spacing and how the remaining six domains enable bridging of distinct intercellular distances.
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Affiliation(s)
- Lucas M. P. Chataigner
- grid.5477.10000000120346234Structural Biochemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Christos Gogou
- grid.5292.c0000 0001 2097 4740Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Maurits A. den Boer
- grid.5477.10000000120346234Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Cátia P. Frias
- grid.5292.c0000 0001 2097 4740Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Dominique M. E. Thies-Weesie
- grid.5477.10000000120346234Van’t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute of Nanomaterials Science, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Joke C. M. Granneman
- grid.5477.10000000120346234Structural Biochemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Albert J. R. Heck
- grid.5477.10000000120346234Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Dimphna H. Meijer
- grid.5292.c0000 0001 2097 4740Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Bert J. C. Janssen
- grid.5477.10000000120346234Structural Biochemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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4
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Gao Y, Kong L, Liu S, Liu K, Zhu J. Impact of Neurofascin on Chronic Inflammatory Demyelinating Polyneuropathy via Changing the Node of Ranvier Function: A Review. Front Mol Neurosci 2021; 14:779385. [PMID: 34975399 PMCID: PMC8716720 DOI: 10.3389/fnmol.2021.779385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/15/2021] [Indexed: 11/18/2022] Open
Abstract
The effective conduction of action potential in the peripheral nervous system depends on the structural and functional integrity of the node of Ranvier and paranode. Neurofascin (NF) plays an important role in the conduction of action potential in a saltatory manner. Two subtypes of NF, NF186, and NF155, are involved in the structure of the node of Ranvier. In patients with chronic inflammatory demyelinating polyneuropathy (CIDP), anti-NF antibodies are produced when immunomodulatory dysfunction occurs, which interferes with the conduction of action potential and is considered the main pathogenic factor of CIDP. In this study, we describe the assembling mechanism and anatomical structure of the node of Ranvier and the necessary cell adhesion molecules for its physiological function. The main points of this study are that we summarized the recent studies on the role of anti-NF antibodies in the changes in the node of Ranvier function and its impact on clinical manifestations and analyzed the possible mechanisms underlying the pathogenesis of CIDP.
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Affiliation(s)
- Ying Gao
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Lingxin Kong
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Shan Liu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Kangding Liu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Jie Zhu
- Neuroscience Center, Department of Neurology, The First Hospital of Jilin University, Jilin University, Changchun, China
- Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Karolinska University Hospital Solna, Stockholm, Sweden
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5
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Dutta DJ, Fields RD. Deletion of the Thrombin Proteolytic Site in Neurofascin 155 Causes Disruption of Nodal and Paranodal Organization. Front Cell Neurosci 2021; 15:576609. [PMID: 33815060 PMCID: PMC8010152 DOI: 10.3389/fncel.2021.576609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 02/17/2021] [Indexed: 11/29/2022] Open
Abstract
In the central nervous system, myelin is attached to the axon in the paranodal region by a trimolecular complex of Neurofascin155 (NF155) in the myelin membrane, interacting with Caspr1 and Contactin1 on the axolemma. Alternative splicing of a single Neurofascin transcript generates several different Neurofascins expressed by several cell types, but NF155, which is expressed by oligodendrocytes, contains a domain in the third fibronectinIII-like region of the molecule that is unique. The immunoglobulin 5–6 domain of NF155 is essential for binding to Contactin1, but less is known about the functions of the NF155-unique third fibronectinIII-like domain. Mutations and autoantibodies to this region are associated with several neurodevelopmental and demyelinating nervous system disorders. Here we used Crispr-Cas9 gene editing to delete a 9 bp sequence of NF155 in this unique domain, which has recently been identified as a thrombin binding site and implicated in plasticity of the myelin sheath. This small deletion results in dysmyelination, eversion of paranodal loops of myelin, substantial enlargement of the nodal gap, a complete loss of paranodal septate junctions, and mislocalization of Caspr1 and nodal sodium channels. The animals exhibit tremor and ataxia, and biochemical and mass spectrometric analysis indicates that while NF155 is transcribed and spliced normally, the NF155 protein is subsequently degraded, resulting in loss of the full length 155 kDa native protein. These findings reveal that this 9 bp region of NF155 in its unique third fibronectinIII-like domain is essential for stability of the protein.
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Affiliation(s)
- Dipankar J Dutta
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - R Douglas Fields
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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6
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Chataigner LMP, Leloup N, Janssen BJC. Structural Perspectives on Extracellular Recognition and Conformational Changes of Several Type-I Transmembrane Receptors. Front Mol Biosci 2020; 7:129. [PMID: 32850948 PMCID: PMC7427315 DOI: 10.3389/fmolb.2020.00129] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
Type-I transmembrane proteins represent a large group of 1,412 proteins in humans with a multitude of functions in cells and tissues. They are characterized by an extracellular, or luminal, N-terminus followed by a single transmembrane helix and a cytosolic C-terminus. The domain composition and structures of the extracellular and intercellular segments differ substantially amongst its members. Most of the type-I transmembrane proteins have roles in cell signaling processes, as ligands or receptors, and in cellular adhesion. The extracellular segment often determines specificity and can control signaling and adhesion. Here we focus on recent structural understanding on how the extracellular segments of several diverse type-I transmembrane proteins engage in interactions and can undergo conformational changes for their function. Interactions at the extracellular side by proteins on the same cell or between cells are enhanced by the transmembrane setting. Extracellular conformational domain rearrangement and structural changes within domains alter the properties of the proteins and are used to regulate signaling events. The combination of structural properties and interactions can support the formation of larger-order assemblies on the membrane surface that are important for cellular adhesion and intercellular signaling.
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Affiliation(s)
- Lucas M. P. Chataigner
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Nadia Leloup
- Structural Biology and Protein Biochemistry, Morphic Therapeutic, Waltham, MA, United States
| | - Bert J. C. Janssen
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
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7
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Iijima T, Yoshimura T. A Perspective on the Role of Dynamic Alternative RNA Splicing in the Development, Specification, and Function of Axon Initial Segment. Front Mol Neurosci 2019; 12:295. [PMID: 31866821 PMCID: PMC6906172 DOI: 10.3389/fnmol.2019.00295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/15/2019] [Indexed: 11/13/2022] Open
Abstract
Alternative splicing is a powerful mechanism for molecular and functional diversification. In neurons, alternative splicing extensively controls various developmental steps as well as the plasticity and remodeling of neuronal activity in the adult brain. The axon initial segment (AIS) is the specialized compartment of proximal axons that initiates action potential (AP). At the AIS, the ion channels and cell adhesion molecules (CAMs) required for AP initiation are densely clustered via the scaffolding and cytoskeletal proteins. Notably, recent studies have elucidated that multiple AIS proteins are controlled by extensive alternative splicing in developing and adult brains. Here, we argue the potential role of dynamic regulation of alternative splicing in the development, specification, and functions of the AIS. In particular, we propose the novel concept that alternative splicing potentially modulates the structural and functional plasticity at the AIS.
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Affiliation(s)
- Takatoshi Iijima
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, Isehara, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita, Japan
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8
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Kvarnung M, Shahsavani M, Taylan F, Moslem M, Breeuwsma N, Laan L, Schuster J, Jin Z, Nilsson D, Lieden A, Anderlid BM, Nordenskjöld M, Syk Lundberg E, Birnir B, Dahl N, Nordgren A, Lindstrand A, Falk A. Ataxia in Patients With Bi-Allelic NFASC Mutations and Absence of Full-Length NF186. Front Genet 2019; 10:896. [PMID: 31608123 PMCID: PMC6769111 DOI: 10.3389/fgene.2019.00896] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/23/2019] [Indexed: 01/29/2023] Open
Abstract
The etiology of hereditary ataxia syndromes is heterogeneous, and the mechanisms underlying these disorders are often unknown. Here, we utilized exome sequencing in two siblings with progressive ataxia and muscular weakness and identified a novel homozygous splice mutation (c.3020-1G > A) in neurofascin (NFASC). In RNA extracted from fibroblasts, we showed that the mutation resulted in inframe skipping of exon 26, with a deprived expression of the full-length transcript that corresponds to NFASC isoform NF186. To further investigate the disease mechanisms, we reprogrammed fibroblasts from one affected sibling to induced pluripotent stem cells, directed them to neuroepithelial stem cells and finally differentiated to neurons. In early neurogenesis, differentiating cells with selective depletion of the NF186 isoform showed significantly reduced neurite outgrowth as well as fewer emerging neurites. Furthermore, whole-cell patch-clamp recordings of patient-derived neuronal cells revealed a lower threshold for openings, indicating altered Na+ channel kinetics, suggesting a lower threshold for openings as compared to neuronal cells without the NFASC mutation. Taken together, our results suggest that loss of the full-length NFASC isoform NF186 causes perturbed neurogenesis and impaired neuronal biophysical properties resulting in a novel early-onset autosomal recessive ataxia syndrome.
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Affiliation(s)
- Malin Kvarnung
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mansoureh Shahsavani
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, Sweden
| | - Fulya Taylan
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mohsen Moslem
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, Sweden
| | - Nicole Breeuwsma
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, Sweden
| | - Loora Laan
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Jens Schuster
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Zhe Jin
- Department of Neuroscience, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Daniel Nilsson
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Agne Lieden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Magnus Nordenskjöld
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Elisabeth Syk Lundberg
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Bryndis Birnir
- Department of Neuroscience, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Niklas Dahl
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Ann Nordgren
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Lindstrand
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Falk
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, Sweden
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9
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Suzuki S, Ayukawa N, Okada C, Tanaka M, Takekoshi S, Iijima Y, Iijima T. Spatio-temporal and dynamic regulation of neurofascin alternative splicing in mouse cerebellar neurons. Sci Rep 2017; 7:11405. [PMID: 28900163 PMCID: PMC5595909 DOI: 10.1038/s41598-017-11319-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022] Open
Abstract
Alternative splicing is crucial for molecular diversification, which greatly contributes to the complexity and specificity of neural functions in the central nervous system (CNS). Neurofascin (NF) is a polymorphic cell surface protein that has a number of splicing isoforms. As the alternative splicing of the neurofascin gene (Nfasc) is developmentally regulated, NF isoforms have distinct functions in immature and mature brains. However, the molecular mechanisms underlying the alternative splicing of Nfasc in neurons are not yet understood. Here, we demonstrate that, alongside developmental regulation, Nfasc alternative splicing is spatially controlled in the mouse brain. We then identified distinct Nfasc splicing patterns at the cell-type level in the cerebellum, with Nfasc186 being expressed in Purkinje cells and absent from granule cells (GCs). Furthermore, we show that high K+-induced depolarization triggers a shift in splicing from Nfasc140 to Nfasc186 in cerebellar GCs. Finally, we identified a neural RNA-binding protein, Rbfox, as a key player in neural NF isoform selection, specifically controlling splicing at exons 26−29. Together, our results show that Nfasc alternative splicing is spatio-temporally and dynamically regulated in cerebellar neurons. Our findings provide profound insight into the mechanisms underlying the functional diversity of neuronal cell-adhesive proteins in the mammalian CNS.
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Affiliation(s)
- Satoko Suzuki
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; and 411 Kitakaname, Hiratsuka City, Kanagawa, 259-1292, Japan
| | - Noriko Ayukawa
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; and 411 Kitakaname, Hiratsuka City, Kanagawa, 259-1292, Japan
| | - Chisa Okada
- Support Center for Medical Research and Education, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa, 259-1193, Japan
| | - Masami Tanaka
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; and 411 Kitakaname, Hiratsuka City, Kanagawa, 259-1292, Japan
| | - Susumu Takekoshi
- Department of Cell Biology, Division of Host Defense Mechanism, School of Medicine, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa, 259-1193, Japan
| | - Yoko Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; and 411 Kitakaname, Hiratsuka City, Kanagawa, 259-1292, Japan
| | - Takatoshi Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; and 411 Kitakaname, Hiratsuka City, Kanagawa, 259-1292, Japan.
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10
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Abstract
Parkinson's disease (PD) is an age-dependent neurodegenerative disease that often occurs in those over age 60. Although rodents and small animals have been used widely to model PD and investigate its pathology, their short life span makes it difficult to assess the aging-related pathology that is likely to occur in PD patient brains. Here, we used brain tissues from rhesus monkeys at 2-3, 7-8, and >15 years of age to examine the expression of Parkin, PINK1, and α-synuclein, which are known to cause PD via loss- or gain-of-function mechanisms. We found that α-synuclein is increased in the older monkey brains, whereas Parkin and PINK1 are decreased or remain unchanged. Because of the gain of toxicity of α-synuclein, we performed stereotaxic injection of lentiviral vectors expressing mutant α-synuclein (A53T) into the substantia nigra of monkeys and found that aging also increases the accumulation of A53T in neurites and its associated neuropathology. A53T also causes more extensive reactive astrocytes and axonal degeneration in monkey brain than in mouse brain. Using monkey brain tissues, we found that A53T interacts with neurofascin, an adhesion molecule involved in axon subcellular targeting and neurite outgrowth. Aged monkey brain tissues show an increased interaction of neurofascin with A53T. Overexpression of A53T causes neuritic toxicity in cultured neuronal cells, which can be attenuated by transfected neurofascin. These findings from nonhuman primate brains reveal age-dependent pathological and molecular changes that could contribute to the age-dependent neuropathology in PD.
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11
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Ebel J, Beuter S, Wuchter J, Kriebel M, Volkmer H. Organisation and Control of Neuronal Connectivity and Myelination by Cell Adhesion Molecule Neurofascin. ADVANCES IN NEUROBIOLOGY 2014; 8:231-47. [DOI: 10.1007/978-1-4614-8090-7_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Nagaraj K, Mualla R, Hortsch M. The L1 Family of Cell Adhesion Molecules: A Sickening Number of Mutations and Protein Functions. ADVANCES IN NEUROBIOLOGY 2014; 8:195-229. [DOI: 10.1007/978-1-4614-8090-7_9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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13
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Yamasaki R. Anti-neurofascin antibody in combined central and peripheral demyelination. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/cen3.12061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Ryo Yamasaki
- Department of Neurological Therapeutics; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
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14
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Volkmer H, Schreiber J, Rathjen FG. Regulation of adhesion by flexible ectodomains of IgCAMs. Neurochem Res 2012; 38:1092-9. [PMID: 23054071 DOI: 10.1007/s11064-012-0888-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 09/10/2012] [Indexed: 01/06/2023]
Abstract
To perform their diverse biological functions the adhesion activities of the cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) might be regulated by local clustering, proteolytical shedding of their ectodomains or rapid recycling to and from the plasma membrane. Another form of regulation of adhesion might be obtained through flexible ectodomains of IgCAMs which adopt distinct conformations and which in turn modulate their adhesion activity. Here, we discuss variations in the conformation of the extracellular domains of CEACAM1 and CAR that might influence their binding and signaling activities. Furthermore, we concentrate on alternative splicing of single domains and short segments in the extracellular regions of L1 subfamily members that might affect the organization of the N-terminal located Ig-like domains. In particular, we discuss variations of the linker sequence between Ig-like domains 2 and 3 (D2 and D3) that is required for the horseshoe conformation.
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Affiliation(s)
- Hansjürgen Volkmer
- Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Markwiesenstr. 55, 72770 Reutlingen, Germany
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15
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Mualla R, Nagaraj K, Hortsch M. A phylogenetic analysis of the L1 family of neural cell adhesion molecules. Neurochem Res 2012; 38:1196-207. [PMID: 23011207 DOI: 10.1007/s11064-012-0892-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/10/2012] [Accepted: 09/12/2012] [Indexed: 11/25/2022]
Abstract
L1-type genes form one of several distinct gene families that encode adhesive proteins, which are predominantly expressed in developing and mature metazoan nervous systems. These proteins have a multitude of different important cellular functions in neuronal and glial cells. L1-type gene products are transmembrane proteins with a characteristic extracellular domain structure consisting of six immunoglobulin and three to five fibronectin type III protein folds. As reported here, L1-type proteins can be identified in most metazoan phyla with the notable exception of Porifera (sponges). This puts the origin of L1-type genes at a point in time when primitive cellular neural networks emerged, approximately 1,200 to 1,500 million years ago. Subsequently, several independent gene duplication events generated multiple paralogous L1-type genes in some phyla, allowing for a considerable diversification of L1 structures and the emergence of new functional features and molecular interactions. One such evolutionary newer feature is the appearance of RGD integrin-binding motifs in some vertebrate L1 family members.
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Affiliation(s)
- Rula Mualla
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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16
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Rodrigues F, Thuma L, Klämbt C. The regulation of glial-specific splicing of Neurexin IV requires HOW and Cdk12 activity. Development 2012; 139:1765-76. [PMID: 22461565 DOI: 10.1242/dev.074070] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The differentiation of the blood-brain barrier (BBB) is an essential process in the development of a complex nervous system and depends on alternative splicing. In the fly BBB, glial cells establish intensive septate junctions that require the cell-adhesion molecule Neurexin IV. Alternative splicing generates two different Neurexin IV isoforms: Neurexin IV(exon3), which is found in cells that form septate junctions, and Neurexin IV(exon4), which is found in neurons that form no septate junctions. Here, we show that the formation of the BBB depends on the RNA-binding protein HOW (Held out wings), which triggers glial specific splicing of Neurexin IV(exon3). Using a set of splice reporters, we show that one HOW-binding site is needed to include one of the two mutually exclusive exons 3 and 4, whereas binding at the three further motifs is needed to exclude exon 4. The differential splicing is controlled by nuclear access of HOW and can be induced in neurons following expression of nuclear HOW. Using a novel in vivo two-color splicing detector, we then screened for genes required for full HOW activity. This approach identified Cyclin-dependent kinase 12 (Cdk12) and the splicesosomal component Prp40 as major determinants in regulating HOW-dependent splicing of Neurexin IV. Thus, in addition to the control of nuclear localization of HOW, the phosphorylation of the C-terminal domain of the RNA polymerase II by Cdk12 provides an elegant mechanism in regulating timed splicing of newly synthesized mRNA molecules.
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Affiliation(s)
- Floriano Rodrigues
- Institut für Neurobiologie, Universität Münster, Badestrasse 9, 48149 Münster, Germany
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Kriebel M, Wuchter J, Trinks S, Volkmer H. Neurofascin: a switch between neuronal plasticity and stability. Int J Biochem Cell Biol 2012; 44:694-7. [PMID: 22306302 DOI: 10.1016/j.biocel.2012.01.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/17/2012] [Accepted: 01/18/2012] [Indexed: 12/23/2022]
Abstract
Neurofascin (NF) is a cell surface protein belonging to the immunoglobulin superfamily (IgSF). Different polypeptides of 186, 180, 166 and 155 kDa are generated by alternative splicing. Expression of these isoforms is temporally and spatially regulated and can be roughly grouped into embryonic, adult and glial expression. NF interacts with many different interaction partners both extra- and intracellularly. Interactions of NF166 and NF180 selectively regulate mechanisms of plasticity like neurite outgrowth and the formation postsynaptic components. By contrast, NF155 and NF186 confer stabilization of neural structures by interaction with voltage-gated sodium channels and ankyrinG at axon initial segments (AIS) or nodes of Ranvier as well as neuron-glia interactions at the paranodes. Alternatively spliced isoforms of neurofascin may therefore balance dynamic and stabilizing mechanisms of the CNS.
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Affiliation(s)
- Martin Kriebel
- Dept. Molecular Biology, Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Markwiesenstr. 55, 72770 Reutlingen, Germany
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18
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Kriebel M, Metzger J, Trinks S, Chugh D, Harvey RJ, Harvey K, Volkmer H. The cell adhesion molecule neurofascin stabilizes axo-axonic GABAergic terminals at the axon initial segment. J Biol Chem 2011; 286:24385-93. [PMID: 21576239 DOI: 10.1074/jbc.m110.212191] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cell adhesion molecules regulate synapse formation and maintenance via transsynaptic contact stabilization involving both extracellular interactions and intracellular postsynaptic scaffold assembly. The cell adhesion molecule neurofascin is localized at the axon initial segment of granular cells in rat dentate gyrus, which is mainly targeted by chandelier cells. Lentiviral shRNA-mediated knockdown of neurofascin in adult rat brain indicates that neurofascin regulates the number and size of postsynaptic gephyrin scaffolds, the number of GABA(A) receptor clusters as well as presynaptic glutamate decarboxylase-positive terminals at the axon initial segment. By contrast, overexpression of neurofascin in hippocampal neurons increases gephyrin cluster size presumably via stimulation of fibroblast growth factor receptor 1 signaling pathways.
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Affiliation(s)
- Martin Kriebel
- Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, 72770 Reutlingen, Germany
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Thaxton C, Pillai AM, Pribisko AL, Dupree JL, Bhat MA. Nodes of Ranvier act as barriers to restrict invasion of flanking paranodal domains in myelinated axons. Neuron 2011; 69:244-57. [PMID: 21262464 DOI: 10.1016/j.neuron.2010.12.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2010] [Indexed: 11/16/2022]
Abstract
Accumulation of voltage-gated sodium (Na(v)) channels at nodes of Ranvier is paramount for action potential propagation along myelinated fibers, yet the mechanisms governing nodal development, organization, and stabilization remain unresolved. Here, we report that genetic ablation of the neuron-specific isoform of Neurofascin (Nfasc(NF¹⁸⁶)) in vivo results in nodal disorganization, including loss of Na(v) channel and ankyrin-G (AnkG) enrichment at nodes in the peripheral nervous system (PNS) and central nervous system (CNS). Interestingly, the presence of paranodal domains failed to rescue nodal organization in the PNS and the CNS. Most importantly, using ultrastructural analysis, we demonstrate that the paranodal domains invade the nodal space in Nfasc(NF¹⁸⁶) mutant axons and occlude node formation. Our results suggest that Nfasc(NF¹⁸⁶)-dependent assembly of the nodal complex acts as a molecular boundary to restrict the movement of flanking paranodal domains into the nodal area, thereby facilitating the stereotypic axonal domain organization and saltatory conduction along myelinated axons.
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Affiliation(s)
- Courtney Thaxton
- Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, Chapel Hill, NC 27599-7545, USA
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20
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In vivo deletion of immunoglobulin domains 5 and 6 in neurofascin (Nfasc) reveals domain-specific requirements in myelinated axons. J Neurosci 2010; 30:4868-76. [PMID: 20371806 DOI: 10.1523/jneurosci.5951-09.2010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The formation of paranodal axo-glial junctions is critical for the rapid and efficient propagation of nerve impulses. Genetic ablation of genes encoding the critical paranodal proteins Caspr, contactin (Cont), and the myelinating glia-specific isoform of Neurofascin (Nfasc(NF155)) results in the disruption of the paranodal axo-glial junctions, loss of ion channel segregation, and impaired nerve conduction, but the mechanisms regulating their interactions remain elusive. Here, we report that loss of immunoglobulin (Ig) domains 5 and 6 in Nfasc(NF155) in mice phenocopies complete ablation of Nfasc(NF155). The mutant mice lack paranodal septate junctions, resulting in the diffusion of Caspr and Cont from the paranodes, and redistribution of the juxtaparanodal potassium channels toward the nodes. Although critical for Nfasc(NF155) function, we find that Ig5-6 are dispensable for nodal Nfasc(NF186) function. Moreover, in vitro binding assays using Ig5-6 deletion constructs reveal their importance for the association of Nfasc(NF155) with Cont. These findings provide the first molecular evidence demonstrating domain-specific requirements controlling the association of the paranodal tripartite complex in vivo. Our studies further emphasize that in vivo structure/function analysis is necessary to define the unique protein-protein interactions that differentially regulate the functions of Neurofascins during axonal domain organization.
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21
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Pomicter AD, Shroff SM, Fuss B, Sato-Bigbee C, Brophy PJ, Rasband MN, Bhat MA, Dupree JL. Novel forms of neurofascin 155 in the central nervous system: alterations in paranodal disruption models and multiple sclerosis. Brain 2010; 133:389-405. [PMID: 20129933 PMCID: PMC2822635 DOI: 10.1093/brain/awp341] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 12/14/2009] [Accepted: 12/16/2009] [Indexed: 01/08/2023] Open
Abstract
Stability of the myelin-axon unit is achieved, at least in part, by specialized paranodal junctions comprised of the neuronal heterocomplex of contactin and contactin-associated protein and the myelin protein neurofascin 155. In multiple sclerosis, normal distribution of these proteins is altered, resulting in the loss of the insulating myelin and consequently causing axonal dysfunction. Previously, this laboratory reported that mice lacking the myelin-enriched lipid sulphatide are characterized by a progressive deterioration of the paranodal structure. Here, it is shown that this deterioration is preceded by significant loss of neurofascin 155 clustering at the myelin paranode. Interestingly, prolonged electrophoretic separation revealed the existence of two neurofascin 155 bands, neurofascin 155 high and neurofascin 155 low, which are readily observed following N-linked deglycosylation. Neurofascin 155 high is observed at 7 days of age and reaches peak expression at one month of age, while neurofascin 155 low is first observed at 14 days of age and constantly increases until 5 months of age. Studies using conditional neurofascin knockout mice indicated that neurofascin 155 high and neurofascin 155 low are products of the neurofascin gene and are exclusively expressed by oligodendrocytes within the central nervous system. Neurofascin 155 high is a myelin paranodal protein while the distribution of neurofascin 155 low remains to be determined. While neurofascin 155 high levels are significantly reduced in the sulphatide null mice at 15 days, 30 days and 4 months of age, neurofascin 155 low levels remain unaltered. Although maintained at normal levels, neurofascin 155 low is incapable of preserving paranodal structure, thus indicating that neurofascin 155 high is required for paranodal stability. Additionally, comparisons between neurofascin 155 high and neurofascin 155 low in human samples revealed a significant alteration, specifically in multiple sclerosis plaques.
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Affiliation(s)
- Anthony D. Pomicter
- 1 Department of Anatomy and Neurobiology, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
| | - Seema M. Shroff
- 1 Department of Anatomy and Neurobiology, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
| | - Babette Fuss
- 1 Department of Anatomy and Neurobiology, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
| | - Carmen Sato-Bigbee
- 2 Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Peter J. Brophy
- 3 Centre for Neuroscience Research, University of Edinburgh, Edinburgh, Scotland, UK
| | - Matthew N. Rasband
- 4 Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
| | - Manzoor A. Bhat
- 5 Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Jeffrey L. Dupree
- 1 Department of Anatomy and Neurobiology, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
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Kirschbaum K, Kriebel M, Kranz EU, Pötz O, Volkmer H. Analysis of non-canonical fibroblast growth factor receptor 1 (FGFR1) interaction reveals regulatory and activating domains of neurofascin. J Biol Chem 2009; 284:28533-42. [PMID: 19666467 PMCID: PMC2781396 DOI: 10.1074/jbc.m109.004440] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/15/2009] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor receptors (FGFRs) are important for many different mechanisms, including cell migration, proliferation, differentiation, and survival. Here, we show a new link between FGFR1 and the cell adhesion molecule neurofascin, which is important for neurite outgrowth. After overexpression in HEK293 cells, embryonal neurofascin isoform NF166 was able to associate with FGFR1, whereas the adult isoform NF186, differing from NF166 in additional extracellular sequences, was deficient. Pharmacological inhibitors and overexpression of dominant negative components of the FGFR signaling pathway pointed to the activation of FGFR1 after association with neurofascin in neurite outgrowth assays in chick tectal neurons and rat PC12-E2 cells. Both extra- and intracellular domains of embryonal neurofascin isoform NF166 were able to form complexes with FGFR1 independently. However, the cytosolic domain was both necessary and sufficient for the activation of FGFR1. Cytosolic serine residues 56 and 100 were shown to be essential for the neurite outgrowth-promoting activity of neurofascin, whereas both amino acid residues were dispensable for FGFR1 association. In conclusion, the data suggest a neurofascin intracellular domain, which activates FGFR1 for neurite outgrowth, whereas the extracellular domain functions as an additional, regulatory FGFR1 interaction domain in the course of development.
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Affiliation(s)
| | | | | | - Oliver Pötz
- Biochemistry, Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
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23
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Thaxton C, Bhat MA. Myelination and regional domain differentiation of the axon. Results Probl Cell Differ 2009; 48:1-28. [PMID: 19343313 DOI: 10.1007/400_2009_3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During evolution, as organisms increased in complexity and function, the need for the ensheathment and insulation of axons by glia became vital for faster conductance of action potentials in nerves. Myelination, as the process is termed, facilitates the formation of discrete domains within the axolemma that are enriched in ion channels, and macromolecular complexes consisting of cell adhesion molecules and cytoskeletal regulators. While it is known that glia play a substantial role in the coordination and organization of these domains, the mechanisms involved and signals transduced between the axon and glia, as well as the proteins regulating axo-glial junction formation remain elusive. Emerging evidence has shed light on the processes regulating myelination and domain differentiation, and key molecules have been identified that are required for their assembly and maintenance. This review highlights these recent findings, and relates their significance to domain disorganization as seen in several demyelinating disorders and other neuropathies.
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Affiliation(s)
- Courtney Thaxton
- Department of Cell and Molecular Physiology, Curriculum in Neurobiology, UNC-Neuroscience Center and Neurodevelopmental Disorders Research Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7545, USA
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24
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Lasiecka ZM, Yap CC, Vakulenko M, Winckler B. Chapter 7 Compartmentalizing the Neuronal Plasma Membrane. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 272:303-89. [DOI: 10.1016/s1937-6448(08)01607-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Burkarth N, Kriebel M, Kranz EU, Volkmer H. Neurofascin regulates the formation of gephyrin clusters and their subsequent translocation to the axon hillock of hippocampal neurons. Mol Cell Neurosci 2007; 36:59-70. [PMID: 17681789 DOI: 10.1016/j.mcn.2007.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 05/25/2007] [Accepted: 06/01/2007] [Indexed: 10/23/2022] Open
Abstract
Little is known about the role of cell adhesion molecules (CAMs) in inhibitory synapse development. In particular, a functional link between CAMs and the clustering of postsynaptic scaffold component gephyrin, which is a critical determinant of gamma-aminobutyric acid A (GABA) receptor clustering, still needs to be elaborated. At early stages of inhibitory synapse formation, gephyrin and CAM neurofascin are diffusely expressed in the soma of hippocampal neurons. Subsequently, gephyrin clusters become localized to the axon hillock and neurofascin is observed all over the soma including the axon hillock suggesting a function for neurofascin in gephyrin clustering. Transfection of expression vectors for different isoforms and mutants of neurofascin revealed that neurofascin is required for the formation of gephyrin clusters presumably dependent on extracellular interactions. Furthermore, expression of neurofascin is necessary for the translocation of gephyrin clusters to the axon hillock of hippocampal neurons as shown by shRNA-mediated knockdown. In addition, overexpression of an embryonic neurofascin isoform is sufficient for functional rescue after knockdown of endogenous neurofascin.
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Affiliation(s)
- Nadine Burkarth
- NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Markwiesenstr 55, 72770, Reutlingen, Germany
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Basak S, Raju K, Babiarz J, Kane-Goldsmith N, Koticha D, Grumet M. Differential expression and functions of neuronal and glial neurofascin isoforms and splice variants during PNS development. Dev Biol 2007; 311:408-22. [PMID: 17936266 DOI: 10.1016/j.ydbio.2007.08.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 08/22/2007] [Accepted: 08/23/2007] [Indexed: 10/22/2022]
Abstract
The cell adhesion molecule neurofascin (NF) has a major neuronal isoform (NF186) containing a mucin-like domain followed by a fifth fibronectin type III repeat while these domains are absent from glial NF155. Neuronal NF isoforms lacking one or both of these domains are expressed transiently in embryonic dorsal root ganglia (DRG). These two domains are co-expressed in mature NF186, which peaks in expression prior to birth and then persists almost exclusively at nodes of Ranvier on myelinated axons. In contrast, glial NF155 is only detected postnatally with the onset of myelination. All these forms of NF bound homophilically and to Schwann cells but only the mature NF186 isoform inhibits cell adhesion, and this activity may be important in formation of the node of Ranvier. Schwann cells deficient in NF155 myelinated DRG axons in a delayed manner and they showed significantly decreased clustering of both NF and Caspr in regions where paranodes normally form. The combined results suggest that NF186 is expressed prenatally on DRG neurons and it may modulate their adhesive interactions with Schwann cells, which express NF155 postnatally and require it for development of axon-glial paranodal junctions.
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Affiliation(s)
- Sayantani Basak
- W. M. Keck Center for Collaborative Neuroscience and Dept. of Cell Biology and Neuroscience, Rutgers University, 604 Allison Rd., Piscataway, NJ 08854-8082, USA
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Katyal S, Gao Z, Liu RZ, Godbout R. Evolutionary conservation of alternative splicing in chicken. Cytogenet Genome Res 2007; 117:146-57. [PMID: 17675855 PMCID: PMC3726401 DOI: 10.1159/000103175] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 09/13/2006] [Indexed: 12/21/2022] Open
Abstract
Alternative splicing represents a source of great diversity for regulating protein expression and function. It has been estimated that one-third to two-thirds of mammalian genes are alternatively spliced. With the sequencing of the chicken genome and analysis of transcripts expressed in chicken tissues, we are now in a position to address evolutionary conservation of alternative splicing events in chicken and mammals. Here, we compare chicken and mammalian transcript sequences of 41 alternatively-spliced genes and 50 frequently accessed genes. Our results support a high frequency of splicing events in chicken, similar to that observed in mammals.
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Affiliation(s)
- S Katyal
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada
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28
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Koticha D, Maurel P, Zanazzi G, Kane-Goldsmith N, Basak S, Babiarz J, Salzer J, Grumet M. Neurofascin interactions play a critical role in clustering sodium channels, ankyrin G and beta IV spectrin at peripheral nodes of Ranvier. Dev Biol 2006; 293:1-12. [PMID: 16566914 DOI: 10.1016/j.ydbio.2005.05.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 05/06/2005] [Accepted: 05/11/2005] [Indexed: 01/06/2023]
Abstract
The Ig cell adhesion molecules (CAM) neurofascin (NF) and Nr-CAM are localized at developing nodes of Ranvier in peripheral myelinated axons prior to clustering of Na+ channels. Different isoforms of NF are expressed on neurons and glia, and NF binding on both cells has been suggested to play roles in node and paranode formation. To clarify the role of NF further, we analyzed effects of NF-Fc fusion proteins in Schwann cell-DRG neuron myelinating cocultures. NF-Fc significantly inhibited nodal clustering of Na+ channels, ankyrin G, and betaIV spectrin, and modestly reduced Caspr clustering at paranodal junctions; it did not significantly affect lengths or numbers of myelin-positive segments, axon initial segments, or accumulations of phosphorylated-ERM proteins in Schwann cell nodal microvilli. NF-Fc binds to Schwann cells but little or no binding to DRG neurons was detected. The results suggest a critical early role for axonal NF in clustering of Na+ channels at nodes of Ranvier via interactions with receptors on Schwann cells.
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Affiliation(s)
- Darshan Koticha
- W. M. Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
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29
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Godenschwege TA, Kristiansen LV, Uthaman SB, Hortsch M, Murphey RK. A conserved role for Drosophila Neuroglian and human L1-CAM in central-synapse formation. Curr Biol 2006; 16:12-23. [PMID: 16401420 DOI: 10.1016/j.cub.2005.11.062] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 11/21/2005] [Accepted: 11/22/2005] [Indexed: 11/22/2022]
Abstract
BACKGROUND Drosophila Neuroglian (Nrg) and its vertebrate homolog L1-CAM are cell-adhesion molecules (CAM) that have been well studied in early developmental processes. Mutations in the human gene result in a broad spectrum of phenotypes (the CRASH-syndrome) that include devastating neurological disorders such as spasticity and mental retardation. Although the role of L1-CAMs in neurite extension and axon pathfinding has been extensively studied, much less is known about their role in synapse formation. RESULTS We found that a single extracellular missense mutation in nrg(849) mutants disrupted the physiological function of a central synapse in Drosophila. The identified giant neuron in nrg(849) mutants made a synaptic terminal on the appropriate target, but ultrastructural analysis revealed in the synaptic terminal a dramatic microtubule reduction, which was likely to be the cause for disrupted active zones. Our results reveal that tyrosine phosphorylation of the intracellular ankyrin binding motif was reduced in mutants, and cell-autonomous rescue experiments demonstrated the indispensability of this tyrosine in giant-synapse formation. We also show that this function in giant-synapse formation was conserved in human L1-CAM but neither in human L1-CAM with a pathological missense mutation nor in two isoforms of the paralogs NrCAM and Neurofascin. CONCLUSIONS We conclude that Nrg has a function in synapse formation by organizing microtubules in the synaptic terminal. This novel synaptic function is conserved in human L1-CAM but is not common to all L1-type proteins. Finally, our findings suggest that some aspects of L1-CAM-related neurological disorders in humans may result from a disruption in synapse formation rather than in axon pathfinding.
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Affiliation(s)
- Tanja A Godenschwege
- Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, USA.
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30
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Pruss T, Kranz EU, Niere M, Volkmer H. A regulated switch of chick neurofascin isoforms modulates ligand recognition and neurite extension. Mol Cell Neurosci 2006; 31:354-65. [PMID: 16314110 DOI: 10.1016/j.mcn.2005.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 09/30/2005] [Accepted: 10/12/2005] [Indexed: 10/25/2022] Open
Abstract
Neural cell adhesion molecule neurofascin regulates the induction of neurite outgrowth, the establishment of synaptic connectivity and myelination. Neurofascin isoforms are generated by spatially and temporally controlled alternative splicing. Isoform NF166 is predominantly expressed in dorsal root ganglia from embryonal day 5 (E5) to E8, and a further neurofascin isoform NF185 appears at E9. Expression of neurofascin and its binding partner axonin-1 on sensory fibers implies functional interactions for neurite outgrowth. E7 sensory neurons require NF166-axonin-1 interactions for neurite extension, accordingly. The contribution of NF166-axonin-1 interaction for neurite outgrowth decreases in parallel with the appearance of NF185 on sensory neurons at E9. This finding may be explained by (1) alleviated intrinsic capability to use axonin-1 as a cellular receptor and (2) reduced binding of axonin-1 to NF185. Finally, NF166, but not NF185, serves as a cellular receptor for neurite induction via homophilic interactions with a neurofascin substrate.
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Affiliation(s)
- Thomas Pruss
- NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, NMI, Markwiesenstr. 55, 72770 Reutlingen, Germany
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31
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Maier O, van der Heide T, Johnson R, de Vries H, Baron W, Hoekstra D. The function of neurofascin155 in oligodendrocytes is regulated by metalloprotease-mediated cleavage and ectodomain shedding. Exp Cell Res 2006; 312:500-11. [PMID: 16360652 DOI: 10.1016/j.yexcr.2005.11.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 10/27/2005] [Accepted: 11/09/2005] [Indexed: 02/02/2023]
Abstract
Formation of the paranodal axo-glial junction requires the oligodendrocyte-specific 155-kDa isoform of neurofascin (NF155). Here, we report the presence of two peptides in cultured oligodendrocytes, which are recognized by distinct NF155-specific antibodies and correspond to a membrane anchor of 30 kDa and a 125 kDa peptide, which is shed from the cells, indicating that it consists of the NF155 ectodomain. Transfection of OLN-93 cells with NF155 verified that both peptides originate from NF155 cleavage, and we present evidence that metalloproteases mediate NF155 processing. Interestingly, metalloprotease activity is required for NF155 transport into oligodendrocyte processes supporting the functional significance of NF155 cleavage. To further characterize NF155 cleavage and function, we transfected MDCK cells with NF155. Although ectodomain shedding was observed in polarized and non-polarized MDCK cells, surface localization of NF155 was restricted to the lateral membrane of polarized cells consistent with a role in cell-cell adhesion. Aggregation assays performed with OLN-93 cells confirmed that NF155 accelerates cell-cell adhesion in a metalloprotease-dependent manner. The physiological relevance of NF155 processing is corroborated by the presence of NF155 cleavage products in heavy myelin, suggesting a role of NF155 ectodomain shedding for the generation and/or stabilization of the nodal/paranodal architecture.
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Affiliation(s)
- Olaf Maier
- University Medical Center Groningen, University of Groningen, Department of Cell Biology/Section Membrane Cell Biology, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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Biederer T. Bioinformatic characterization of the SynCAM family of immunoglobulin-like domain-containing adhesion molecules. Genomics 2006; 87:139-50. [PMID: 16311015 DOI: 10.1016/j.ygeno.2005.08.017] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 07/31/2005] [Accepted: 08/15/2005] [Indexed: 12/20/2022]
Abstract
SynCAM 1 (synaptic cell adhesion molecule 1, alternatively named Tslc1 and nectin-like protein 3) belongs to the immunoglobulin superfamily and is an adhesion molecule that operates in a variety of important contexts. Exemplary are its roles in adhesion at synapses in the central nervous system and as tumor suppressor. Here, I describe a family of genes homologous to SynCAM 1 comprising four genes found solely in vertebrates. All SynCAM genes encode proteins with three immunoglobulin-like domains of the V-set, C1-set, and I-set subclasses. Comparison of genomic with cDNA sequences provides their exon-intron structure. Alternative splicing generates isoforms of SynCAM proteins, and diverse SynCAM 1 and 2 isoforms are created in an extracellular region rich in predicted O-glycosylation sites. Protein interaction motifs in the cytosolic sequence are highly conserved among all four SynCAM proteins, indicating their critical functional role. These findings aim to facilitate the understanding of SynCAM genes and provide the framework to examine the physiological functions of this family of vertebrate-specific adhesion molecules.
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Affiliation(s)
- Thomas Biederer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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Camurri L, Mambetisaeva E, Davies D, Parnavelas J, Sundaresan V, Andrews W. Evidence for the existence of two Robo3 isoforms with divergent biochemical properties. Mol Cell Neurosci 2005; 30:485-93. [PMID: 16226035 DOI: 10.1016/j.mcn.2005.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 07/22/2005] [Accepted: 07/25/2005] [Indexed: 11/18/2022] Open
Abstract
Robo3 is a member of the roundabout (Robo) family of proteins that plays a key role in axon guidance and cell migration in the developing nervous system. Recent studies have shown that Robo3 plays a crucial role in controlling axon guidance at the midline of the CNS. Here we describe and compare two human Robo3 isoforms, Robo3A and Robo3B, which differ by the insertion of 26 amino acids at the N-terminus, and these forms appear to be evolutionary conserved. We investigated the bioactivity of these isoforms and show that they have different binding properties to Slit, and that orthologs of these forms are expressed in the mouse embryo. In addition, we show that, like other members of the Robo family, Robo3 can bind homophilically, but it is also capable of binding heterophilically to Robo1 and NCAM. We propose that these properties of Robo3 may contribute to its function at the midline of the CNS.
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Affiliation(s)
- Laura Camurri
- MRC Centre for Developmental Neurobiology, New Hunt's House, King's College, London, Guy's Campus, London SE1 1UL, UK
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Koticha D, Babiarz J, Kane-Goldsmith N, Jacob J, Raju K, Grumet M. Cell adhesion and neurite outgrowth are promoted by neurofascin NF155 and inhibited by NF186. Mol Cell Neurosci 2005; 30:137-48. [PMID: 16061393 DOI: 10.1016/j.mcn.2005.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 06/10/2005] [Accepted: 06/28/2005] [Indexed: 01/06/2023] Open
Abstract
Neurofascin (NF) is a neural cell adhesion molecule in the L1-family containing six Ig domains and multiple fibronectin type III (FnIII) repeats in its extracellular region. NF has many splicing variants and two of these are exemplars that have different cellular patterns of expression during development. NF186, which is expressed on neurons, contains an unusual mucin-like region and NF155, which is expressed on glia, contains a unique FnIII repeat with an RGD motif. Analysis of Fc fusion proteins representing different extracellular regions of NF indicate that NF186 inhibits cell adhesion and neurite outgrowth, and the inhibition is associated with the region containing the mucin-like domain. NF155 promotes neural cell adhesion and neurite outgrowth, and the RGD motif in its third FnIII repeat is critical for cell spreading and neurite outgrowth. The results suggest that different splicing variants of NF expressed on neurons and glia play distinct roles during neural development.
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Affiliation(s)
- Darshan Koticha
- W. M. Keck Center for Collaborative Neuroscience, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8082, USA
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35
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Pimenta AF, Levitt P. Characterization of the genomic structure of the mouse limbic system-associated membrane protein (Lsamp) gene. Genomics 2004; 83:790-801. [PMID: 15081109 DOI: 10.1016/j.ygeno.2003.11.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 10/15/2003] [Accepted: 11/17/2003] [Indexed: 12/12/2022]
Abstract
The Lsamp gene encodes the limbic system-associated membrane protein (LAMP) an immunoglobulin (Ig) superfamily member with three Ig domains and a glycosylphosphatidylinositol anchor. LAMP is expressed by neurons composing the limbic system, is highly conserved between rodents and human, and has structural and functional properties that substantiate its role in the formation of limbic circuits. We report here the genomic organization of the Lsamp gene. The Lsamp gene is composed of 11 exons distributed over 2.2 megabases (Mb). Two exons 1 are separated by approximately 1.6 Mb and contribute to the unusual large size of the gene. Alternative spliced Lsamp mRNAs are generated from distinct promoter regions associated with the two exons 1 that encode distinct signal peptides and thus generate identical native mature polypetides. Additional diversity is created by the use of two small exons to include an insertion of 23 amino acids within the polypeptide C-terminal region of the mature protein. The genomic features of the Lsamp gene described here indicate an intricate mechanism of gene expression regulation that may be relevant in the context of human neuropsychiatric and neurological disorders, where LAMP expression may be altered.
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Affiliation(s)
- Aurea F Pimenta
- John F. Kennedy Center for Research on Human Development and Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
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36
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Rougon G, Hobert O. New insights into the diversity and function of neuronal immunoglobulin superfamily molecules. Annu Rev Neurosci 2003; 26:207-38. [PMID: 12598678 DOI: 10.1146/annurev.neuro.26.041002.131014] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immunoglobulin superfamily (IgSF) proteins are implicated in diverse steps of brain development, including neuronal migration, axon pathfinding, target recognition and synapse formation, as well as in the maintenance and function of neuronal networks in the adult. We provide here a review of recent findings on the diversity and the role of transmembrane and secreted members of IgSF proteins in the nervous system. We illustrate that the complexity of IgSF protein function results from various different levels of regulation including regulation of gene expression, protein localization, and protein interactions.
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Affiliation(s)
- Genevieve Rougon
- Laboratoire NMDA CNRS UMR 6156, Universite de la Mediterranee, Institut de Biologie du Developpement (IBDM), Marseille Cedex 9, 13288 France.
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37
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De Vet ECJM, Aguado B, Campbell RD. Adaptor signalling proteins Grb2 and Grb7 are recruited by human G6f, a novel member of the immunoglobulin superfamily encoded in the MHC. Biochem J 2003; 375:207-13. [PMID: 12852788 PMCID: PMC1223670 DOI: 10.1042/bj20030293] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2003] [Revised: 07/08/2003] [Accepted: 07/09/2003] [Indexed: 11/17/2022]
Abstract
The human G6f protein, which is encoded by a gene in the MHC, is a putative cell-surface receptor belonging to the immunoglobulin superfamily. The intracellular tail of G6f is 40 amino acids in length and contains one tyrosine residue (Y281), which is phosphorylated after treatment of cells with pervanadate. This tyrosine residue is found in a consensus-binding motif (YXN) for the Src homology 2 domains of Grb2 and Grb7 (where Grb stands for growth-factor-receptor-bound protein). Glutathione S-transferase pull-down assays showed that the interaction of G6f with both Grb2 and Grb7 is mediated through the Src homology 2 domains of these two proteins and is dependent on the phosphorylation of G6f. Immunoprecipitation experiments showed the interaction of full-length phosphorylated G6f with both full-length Grb2 and Grb7. Antibody cross-linking of G6f expressed in K562 cells resulted in a transient phosphorylation of p42/44 MAP kinase (also known as extracellular-signal-regulated protein kinase-1/2; MAP stands for mitogen-activated protein) which could be prevented by MAP kinase kinase (MEK) inhibitors. These results suggest a coupling of G6f with downstream signal transduction pathways involving Grb2 and Grb7, including the Ras-MAP kinase pathway.
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Affiliation(s)
- Edwin C J M De Vet
- MRC Rosalind Franklin Centre for Genomics Research, Hinxton, Cambridge CB10 1SB, UK
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38
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Brümmendorf T, Lemmon V. Immunoglobulin superfamily receptors: cis-interactions, intracellular adapters and alternative splicing regulate adhesion. Curr Opin Cell Biol 2001; 13:611-8. [PMID: 11544031 DOI: 10.1016/s0955-0674(00)00259-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The immunoglobulin domain is a module found in vertebrates and invertebrates. Its ability to form linear rods when deployed in series, combined with its propensity to bind specifically to other proteins has made it ideal for building cell surface receptors and cell adhesion molecules. These features have resulted in the incorporation of immunoglobulin domains into many hundreds of cell surface molecules. Recently three major advances have been made in understanding immunoglobulin receptors. One is the recognition that their intracellular binding partners are likely to link to multiple cell surface molecules, allowing cross-talk or oligomeric complex formation. A second, but related phenomenon, is their participation in cis-interactions on the extracellular surface that regulate signaling or adhesion. The third is the dramatic ability to form dozens to thousands of different isoforms via alternative splicing. Although antibodies may have been the first example of immunoglobulin-domain-containing proteins using cis-interactions to form receptor like molecules, and the grandest instance of diversity production from limited genetic material, these are clearly old ideas in this superfamily.
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Affiliation(s)
- T Brümmendorf
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, D-13092 Berlin, Germany.
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39
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Chen L, Ong B, Bennett V. LAD-1, the Caenorhabditis elegans L1CAM homologue, participates in embryonic and gonadal morphogenesis and is a substrate for fibroblast growth factor receptor pathway-dependent phosphotyrosine-based signaling. J Cell Biol 2001; 154:841-55. [PMID: 11502758 PMCID: PMC2196473 DOI: 10.1083/jcb.200009004] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2000] [Revised: 07/11/2001] [Accepted: 07/12/2001] [Indexed: 11/30/2022] Open
Abstract
This study shows that L1-like adhesion (LAD-1), the sole Caenorhabditis elegans homologue of the L1 family of neuronal adhesion molecules, is required for proper development of the germline and the early embryo and embryonic and gonadal morphogenesis. In addition, the ubiquitously expressed LAD-1, which binds to ankyrin-G, colocalizes with the C. elegans ankyrin, UNC-44, in multiple tissues at sites of cell-cell contact. Finally, we show that LAD-1 is phosphorylated in a fibroblast growth factor receptor (FGFR) pathway-dependent manner on a tyrosine residue in the highly conserved ankyrin-binding motif, FIGQY, which was shown previously to abolish the L1 family of cell adhesion molecule (L1CAM) binding to ankyrin in cultured cells. Immunofluorescence studies revealed that FIGQY-tyrosine-phosphorylated LAD-1 does not colocalize with nonphosphorylated LAD-1 or UNC-44 ankyrin but instead is localized to sites that undergo mechanical stress in polarized epithelia and axon-body wall muscle junctions. These findings suggest a novel ankyrin-independent role for LAD-1 related to FGFR signaling. Taken together, these results indicate that L1CAMs constitute a family of ubiquitous adhesion molecules, which participate in tissue morphogenesis and maintaining tissue integrity in metazoans.
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Affiliation(s)
- L Chen
- Howard Hughes Medical Institute, Department of Cell Biology, and Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
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40
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Bennett V, Baines AJ. Spectrin and ankyrin-based pathways: metazoan inventions for integrating cells into tissues. Physiol Rev 2001; 81:1353-92. [PMID: 11427698 DOI: 10.1152/physrev.2001.81.3.1353] [Citation(s) in RCA: 718] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The spectrin-based membrane skeleton of the humble mammalian erythrocyte has provided biologists with a set of interacting proteins with diverse roles in organization and survival of cells in metazoan organisms. This review deals with the molecular physiology of spectrin, ankyrin, which links spectrin to the anion exchanger, and two spectrin-associated proteins that promote spectrin interactions with actin: adducin and protein 4.1. The lack of essential functions for these proteins in generic cells grown in culture and the absence of their genes in the yeast genome have, until recently, limited advances in understanding their roles outside of erythrocytes. However, completion of the genomes of simple metazoans and application of homologous recombination in mice now are providing the first glimpses of the full scope of physiological roles for spectrin, ankyrin, and their associated proteins. These functions now include targeting of ion channels and cell adhesion molecules to specialized compartments within the plasma membrane and endoplasmic reticulum of striated muscle and the nervous system, mechanical stabilization at the tissue level based on transcellular protein assemblies, participation in epithelial morphogenesis, and orientation of mitotic spindles in asymmetric cell divisions. These studies, in addition to stretching the erythrocyte paradigm beyond recognition, also are revealing novel cellular pathways essential for metazoan life. Examples are ankyrin-dependent targeting of proteins to excitable membrane domains in the plasma membrane and the Ca(2+) homeostasis compartment of the endoplasmic reticulum. Exciting questions for the future relate to the molecular basis for these pathways and their roles in a clinical context, either as the basis for disease or more positively as therapeutic targets.
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Affiliation(s)
- V Bennett
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
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41
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Koroll M, Rathjen FG, Volkmer H. The neural cell recognition molecule neurofascin interacts with syntenin-1 but not with syntenin-2, both of which reveal self-associating activity. J Biol Chem 2001; 276:10646-54. [PMID: 11152476 DOI: 10.1074/jbc.m010647200] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurofascin belongs to the L1 subgroup of the immunoglobulin superfamily of cell adhesion molecules and is implicated in axonal growth and fasciculation. We used yeast two-hybrid screening to identify proteins that interact with neurofascin intracellularly and therefore might link it to trafficking, spatial targeting, or signaling pathways. Here, we demonstrate that rat syntenin-1, previously published as syntenin, mda-9, or TACIP18 in human, is a neurofascin-binding protein that exhibits a wide-spread tissue expression pattern with a relative maximum in brain. Syntenin-1 was found not to interact with other vertebrate members of the L1 subgroup such as L1 itself or NrCAM. We confirmed the specificity of the neurofascin-syntenin-1 interaction by ligand-overlay assay, surface plasmon resonance analysis, and colocalization of both proteins in heterologous cells. The COOH terminus of neurofascin was mapped to interact with the second PDZ domain of syntenin-1. Furthermore, we isolated syntenin-2 that may be expressed in two isoforms. Despite their high sequence similarity to syntenin-1, syntenin-2alpha, which interacts with neurexin I, and syntenin-2beta do not bind to neurofascin or several other transmembrane proteins that are binding partners of syntenin-1. Finally, we report that syntenin-1 and -2 both form homodimers and can interact with each other.
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Affiliation(s)
- M Koroll
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, Berlin D-13092, Germany
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42
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Tait S, Gunn-Moore F, Collinson JM, Huang J, Lubetzki C, Pedraza L, Sherman DL, Colman DR, Brophy PJ. An oligodendrocyte cell adhesion molecule at the site of assembly of the paranodal axo-glial junction. J Cell Biol 2000; 150:657-66. [PMID: 10931875 PMCID: PMC2175192 DOI: 10.1083/jcb.150.3.657] [Citation(s) in RCA: 238] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2000] [Accepted: 06/15/2000] [Indexed: 11/22/2022] Open
Abstract
Two major isoforms of the cell adhesion molecule neurofascin NF186 and NF155 are expressed in the central nervous system (CNS). We have investigated their roles in the assembly of the node of Ranvier and show that they are targeted to distinct domains at the node. At the onset of myelination, NF186 is restricted to neurons, whereas NF155 localizes to oligodendrocytes, the myelin-forming glia of the CNS. Coincident with axon ensheathment, NF155 clusters at the paranodal regions of the myelin sheath where it localizes in apposition to the axonal adhesion molecule paranodin/contactin-associated protein (Caspr1), which is a constituent of the septate junction-like axo-glial adhesion zone. Immunoelectron microscopy confirmed that neurofascin is a glial component of the paranodal axo-glial junction. Concentration of NF155 with Caspr1 at the paranodal junctions of peripheral nerves is also a feature of Schwann cells. In Shiverer mutant mice, which assemble neither compact CNS myelin nor normal paranodes, NF155 (though largely retained at the cell body) is also distributed at ectopic sites along axons, where it colocalizes with Caspr1. Hence, NF155 is the first glial cell adhesion molecule to be identified in the paranodal axo-glial junction, where it likely interacts with axonal proteins in close association with Caspr1.
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Affiliation(s)
- Steven Tait
- Department of Preclinical Veterinary Sciences, University of Edinburgh, Edinburgh EH9 1QH, United Kingdom
| | - Frank Gunn-Moore
- Department of Preclinical Veterinary Sciences, University of Edinburgh, Edinburgh EH9 1QH, United Kingdom
| | - J. Martin Collinson
- Department of Preclinical Veterinary Sciences, University of Edinburgh, Edinburgh EH9 1QH, United Kingdom
| | - Jeffery Huang
- Department of Biochemistry and Molecular Biology, Program in Cell Adhesion, Mount Sinai School of Medicine, New York, New York 10029
| | - Catherine Lubetzki
- INSERM U-495, Biologie des Interactions Neurones/Glie, Hôpital de la Salpetrière, 75651 Paris Cedex 13, France
| | - Liliana Pedraza
- Department of Biochemistry and Molecular Biology, Program in Cell Adhesion, Mount Sinai School of Medicine, New York, New York 10029
| | - Diane L. Sherman
- Department of Preclinical Veterinary Sciences, University of Edinburgh, Edinburgh EH9 1QH, United Kingdom
| | - David R. Colman
- Department of Biochemistry and Molecular Biology, Program in Cell Adhesion, Mount Sinai School of Medicine, New York, New York 10029
| | - Peter J. Brophy
- Department of Preclinical Veterinary Sciences, University of Edinburgh, Edinburgh EH9 1QH, United Kingdom
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43
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Salbaum JM, Kappen C. Cloning and expression of nope, a new mouse gene of the immunoglobulin superfamily related to guidance receptors. Genomics 2000; 64:15-23. [PMID: 10708514 DOI: 10.1006/geno.2000.6114] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The novel mouse gene Nope was identified due to its proximity to the Punc gene on chromosome 9. With a domain structure of four immunoglobulin domains, five fibronectin type III repeats, a single transmembrane domain, and a cytoplasmic domain, Nope encodes a new member of the immunoglobulin superfamily of cell surface proteins. It displays a high level of similarity to Punc, as well as to guidance receptors such as the Deleted in Colorectal Cancer protein and Neogenin. Nope is expressed during embryonic development in the notochord, in developing skeletal muscles, and later in the ventricular zone of the nervous system. In the adult brain, Nope can be detected in the hippocampus. Radiation hybrid mapping of Nope, Punc, and Neogenin placed all three genes in close vicinity on mouse chromosome 9.
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Affiliation(s)
- J M Salbaum
- The Neurosciences Institute, 10640 John J. Hopkins Drive, San Diego, CA 92121, USA.
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44
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Hortsch M. Structural and functional evolution of the L1 family: are four adhesion molecules better than one? Mol Cell Neurosci 2000; 15:1-10. [PMID: 10662501 DOI: 10.1006/mcne.1999.0809] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- M Hortsch
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, 48109-0616, USA
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45
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Schaefer AW, Kamiguchi H, Wong EV, Beach CM, Landreth G, Lemmon V. Activation of the MAPK signal cascade by the neural cell adhesion molecule L1 requires L1 internalization. J Biol Chem 1999; 274:37965-73. [PMID: 10608864 DOI: 10.1074/jbc.274.53.37965] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
L1-mediated axon growth involves intracellular signaling, but the precise mechanisms involved are not yet clear. We report a role for the mitogen-activated protein kinase (MAPK) cascade in L1 signaling. L1 physically associates with the MAPK cascade components Raf-1, ERK2, and the previously identified p90(rsk) in brain. In vitro, ERK2 can phosphorylate L1 at Ser(1204) and Ser(1248) of the L1 cytoplasmic domain. These two serines are conserved in the L1 family of cell adhesion molecules, also being found in neurofascin and NrCAM. The ability of ERK2 to phosphorylate L1 suggests that L1 signaling could directly regulate L1 function by phosphorylation of the L1 cytoplasmic domain. In L1-expressing 3T3 cells, L1 cross-linking can activate ERK2. Remarkably, the activated ERK localizes with endocytosed vesicular L1 rather than cell surface L1, indicating that L1 internalization and signaling are coupled. Inhibition of L1 internalization with dominant-negative dynamin prevents activation of ERK. These results show that L1-generated signals activate the MAPK cascade in a manner most likely to be important in regulating L1 intracellular trafficking.
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Affiliation(s)
- A W Schaefer
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106-4975, USA
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46
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Scotland P, Zhou D, Benveniste H, Bennett V. Nervous system defects of AnkyrinB (-/-) mice suggest functional overlap between the cell adhesion molecule L1 and 440-kD AnkyrinB in premyelinated axons. J Cell Biol 1998; 143:1305-15. [PMID: 9832558 PMCID: PMC2133070 DOI: 10.1083/jcb.143.5.1305] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Revised: 10/19/1998] [Indexed: 11/23/2022] Open
Abstract
The L1 CAM family of cell adhesion molecules and the ankyrin family of spectrin-binding proteins are candidates to collaborate in transcellular complexes used in diverse contexts in nervous systems of vertebrates and invertebrates. This report presents evidence for functional coupling between L1 and 440-kD ankyrinB in premyelinated axons in the mouse nervous system. L1 and 440-kD ankyrinB are colocalized in premyelinated axon tracts in the developing nervous system and are both down-regulated after myelination. AnkyrinB (-/-) mice exhibit a phenotype similar to, but more severe, than L1 (-/-) mice and share features of human patients with L1 mutations. AnkyrinB (-/-) mice exhibit hypoplasia of the corpus callosum and pyramidal tracts, dilated ventricles, and extensive degeneration of the optic nerve, and they die by postnatal day 21. AnkyrinB (-/-) mice have reduced L1 in premyelinated axons of long fiber tracts, including the corpus callosum, fimbria, and internal capsule in the brain, and pyramidal tracts and lateral columns of the spinal cord. L1 was evident in the optic nerve at postnatal day 1 but disappeared by postnatal day 7 in mutant mice while NCAM was unchanged. Optic nerve axons of ankyrinB (-/-) mice become dilated with diameters up to eightfold greater than normal, and they degenerated by day 20. These findings provide the first evidence for a role of ankyrinB in the nervous system and support an interaction between 440-kD ankyrinB and L1 that is essential for maintenance of premyelinated axons in vivo.
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Affiliation(s)
- P Scotland
- Howard Hughes Medical Institute, Departments of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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47
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Volkmer H, Zacharias U, Nörenberg U, Rathjen FG. Dissection of complex molecular interactions of neurofascin with axonin-1, F11, and tenascin-R, which promote attachment and neurite formation of tectal cells. J Cell Biol 1998; 142:1083-93. [PMID: 9722619 PMCID: PMC2132869 DOI: 10.1083/jcb.142.4.1083] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/1998] [Revised: 07/13/1998] [Indexed: 02/08/2023] Open
Abstract
Neurofascin is a member of the L1 subgroup of the Ig superfamily that promotes axon outgrowth by interactions with neuronal NgCAM-related cell adhesion molecule (NrCAM). We used a combination of cellular binding assays and neurite outgrowth experiments to investigate mechanisms that might modulate the interactions of neurofascin. In addition to NrCAM, we here demonstrate that neurofascin also binds to the extracellular matrix glycoprotein tenascin-R (TN-R) and to the Ig superfamily members axonin-1 and F11. Isoforms of neurofascin that are generated by alternative splicing show different preferences in ligand binding. While interactions of neurofascin with F11 are only slightly modulated, binding to axonin-1 and TN-R is strongly regulated by alternatively spliced stretches located in the NH2-terminal half, and by the proline-alanine-threonine-rich segment. In vitro neurite outgrowth and cell attachment assays on a neurofascin-Fc substrate reveal a shift of cellular receptor usage from NrCAM to axonin-1, F11, and at least one additional protein in the presence of TN-R, presumably due to competition of the neurofascin- NrCAM interaction. Thereby, F11 binds to TN-R of the neurofascin/TN-R complex, but not to neurofascin, whereas axonin-1 is not able to bind directly to the neurofascin/TN-R complex as shown by competition binding assays. In conclusion, these investigations indicate that the molecular interactions of neurofascin are regulated at different levels, including alternative splicing and by the presence of interacting proteins.
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Affiliation(s)
- H Volkmer
- Max-Delbrück-Centrum für Molekulare Medizin, D-13122 Berlin, Germany
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48
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Zhao G, Hortsch M. The analysis of genomic structures in the L1 family of cell adhesion molecules provides no evidence for exon shuffling events after the separation of arthropod and chordate lineages. Gene X 1998; 215:47-55. [PMID: 9666073 DOI: 10.1016/s0378-1119(98)00273-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Members of the L1 family of neural cell adhesion molecules consist of multiple extracellular immunoglobulin and fibronectin type III domains that mediate the adhesive properties of this group of transmembrane proteins. In vertebrate genomes, these protein domains are separated by introns, and it has been suggested that L1-type genes might have been subject to exon-shuffling events during evolution. However, comparison of the human L1-CAM and the chicken neurofascin gene with the genomic structure of their Drosophila homologue, neuroglian, indicates that no major rearrangement of protein domains has taken place subsequent to the split of the arthropod and chordate phyla. The Drosophila neuroglian gene appears to have lost most of the introns that have been conserved in the human L1-CAM and the chicken neurofascin gene. Nevertheless, exon shuffling or the generation of new exons by mutational changes might have been responsible for the generation of additional, alternatively spliced exons in L1-type genes.
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Affiliation(s)
- G Zhao
- University of Michigan, Department of Anatomy, Cell Biology, Ann Arbor, MI 48109-0616, USA
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49
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Brümmendorf T, Kenwrick S, Rathjen FG. Neural cell recognition molecule L1: from cell biology to human hereditary brain malformations. Curr Opin Neurobiol 1998; 8:87-97. [PMID: 9568396 DOI: 10.1016/s0959-4388(98)80012-3] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The neural cell recognition molecule L1 is a member of the immunoglobulin superfamily implicated in embryonic brain development. L1 is engaged in complex extracellular interactions, with multiple binding partners on cell surfaces and in the extracellular matrix. It is the founder of a neural group of related cell surface receptors that share with L1 a highly conserved cytoplasmic domain that associates with the cytoskeleton. Phenotypic analyses of human patients with mutations in the L1 gene and characterizations of L1-deficient mice suggest that L1 is important for embryonic brain histogenesis, in particular the development of axon tracts.
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Affiliation(s)
- T Brümmendorf
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.
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