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Licheri V, Brigman JL. Altering Cell-Cell Interaction in Prenatal Alcohol Exposure Models: Insight on Cell-Adhesion Molecules During Brain Development. Front Mol Neurosci 2022; 14:753537. [PMID: 34975396 PMCID: PMC8715949 DOI: 10.3389/fnmol.2021.753537] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/11/2021] [Indexed: 11/17/2022] Open
Abstract
Alcohol exposure during pregnancy disrupts the development of the brain and produces long lasting behavioral and cognitive impairments collectively known as Fetal Alcohol Spectrum Disorders (FASDs). FASDs are characterized by alterations in learning, working memory, social behavior and executive function. A large body of literature using preclinical prenatal alcohol exposure models reports alcohol-induced changes in architecture and activity in specific brain regions affecting cognition. While multiple putative mechanisms of alcohol’s long-lasting effects on morphology and behavior have been investigated, an area that has received less attention is the effect of alcohol on cell adhesion molecules (CAMs). The embryo/fetal development represents a crucial period for Central Nervous System (CNS) development during which the cell-cell interaction plays an important role. CAMs play a critical role in neuronal migration and differentiation, synaptic organization and function which may be disrupted by alcohol. In this review, we summarize the physiological structure and role of CAMs involved in brain development, review the current literature on prenatal alcohol exposure effects on CAM function in different experimental models and pinpoint areas needed for future study to better understand how CAMs may mediate the morphological, sensory and behavioral outcomes in FASDs.
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Affiliation(s)
- Valentina Licheri
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, United States.,New Mexico Alcohol Research Center, UNM Health Sciences Center, Albuquerque, NM, United States
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2
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Cheng Q, He B, Zhao C, Bi H, Chen D, Han S, Gao H, Feng W. Prediction of functional microexons by transfer learning. BMC Genomics 2021; 22:855. [PMID: 34836511 PMCID: PMC8627023 DOI: 10.1186/s12864-021-08187-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
Background Microexons are a particular kind of exon of less than 30 nucleotides in length. More than 60% of annotated human microexons were found to have high levels of sequence conservation, suggesting their potential functions. There is thus a need to develop a method for predicting functional microexons. Results Given the lack of a publicly available functional label for microexons, we employed a transfer learning skill called Transfer Component Analysis (TCA) to transfer the knowledge obtained from feature mapping for the prediction of functional microexons. To provide reference knowledge, microindels were chosen because of their similarities to microexons. Then, Support Vector Machine (SVM) was used to train a classification model in the newly built feature space for the functional microindels. With the trained model, functional microexons were predicted. We also built a tool based on this model to predict other functional microexons. We then used this tool to predict a total of 19 functional microexons reported in the literature. This approach successfully predicted 16 out of 19 samples, giving accuracy greater than 80%. Conclusions In this study, we proposed a method for predicting functional microexons and applied it, with the predictive results being largely consistent with records in the literature.
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Affiliation(s)
- Qi Cheng
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Bo He
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China.
| | - Chengkui Zhao
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Hongyuan Bi
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Duojiao Chen
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Shuangze Han
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Haikuan Gao
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China
| | - Weixing Feng
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, China.
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3
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Jarahian M, Marofi F, Maashi MS, Ghaebi M, Khezri A, Berger MR. Re-Expression of Poly/Oligo-Sialylated Adhesion Molecules on the Surface of Tumor Cells Disrupts Their Interaction with Immune-Effector Cells and Contributes to Pathophysiological Immune Escape. Cancers (Basel) 2021; 13:5203. [PMID: 34680351 PMCID: PMC8534074 DOI: 10.3390/cancers13205203] [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: 09/07/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/28/2022] Open
Abstract
Glycans linked to surface proteins are the most complex biological macromolecules that play an active role in various cellular mechanisms. This diversity is the basis of cell-cell interaction and communication, cell growth, cell migration, as well as co-stimulatory or inhibitory signaling. Our review describes the importance of neuraminic acid and its derivatives as recognition elements, which are located at the outermost positions of carbohydrate chains linked to specific glycoproteins or glycolipids. Tumor cells, especially from solid tumors, mask themselves by re-expression of hypersialylated neural cell adhesion molecule (NCAM), neuropilin-2 (NRP-2), or synaptic cell adhesion molecule 1 (SynCAM 1) in order to protect themselves against the cytotoxic attack of the also highly sialylated immune effector cells. More particularly, we focus on α-2,8-linked polysialic acid chains, which characterize carrier glycoproteins such as NCAM, NRP-2, or SynCam-1. This characteristic property correlates with an aggressive clinical phenotype and endows them with multiple roles in biological processes that underlie all steps of cancer progression, including regulation of cell-cell and/or cell-extracellular matrix interactions, as well as increased proliferation, migration, reduced apoptosis rate of tumor cells, angiogenesis, and metastasis. Specifically, re-expression of poly/oligo-sialylated adhesion molecules on the surface of tumor cells disrupts their interaction with immune-effector cells and contributes to pathophysiological immune escape. Further, sialylated glycoproteins induce immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. We describe the processes, which modulate the interaction between sialylated carrier glycoproteins and their ligands, and illustrate that sialic acids could be targets of novel therapeutic strategies for treatment of cancer and immune diseases.
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Affiliation(s)
- Mostafa Jarahian
- German Cancer Research Center, Toxicology and Chemotherapy Unit Heidelberg, 69120 Heidelberg, Germany;
| | - Faroogh Marofi
- Department of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz 5165665931, Iran;
| | - Marwah Suliman Maashi
- Stem Cells and Regenerative Medicine Unit at King Fahad Medical Research Centre, Jeddah 11211, Saudi Arabia;
| | - Mahnaz Ghaebi
- Cancer Gene Therapy Research Center (CGRC), Zanjan University of Medical Sciences, Zanjan 4513956184, Iran;
| | - Abdolrahman Khezri
- Department of Biotechnology, Inland Norway University of Applied Sciences, 2418 Hamar, Norway;
| | - Martin R. Berger
- German Cancer Research Center, Toxicology and Chemotherapy Unit Heidelberg, 69120 Heidelberg, Germany;
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4
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Parada GE, Munita R, Georgakopoulos-Soares I, Fernandes HJR, Kedlian VR, Metzakopian E, Andres ME, Miska EA, Hemberg M. MicroExonator enables systematic discovery and quantification of microexons across mouse embryonic development. Genome Biol 2021; 22:43. [PMID: 33482885 PMCID: PMC7821500 DOI: 10.1186/s13059-020-02246-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microexons, exons that are ≤ 30 nucleotides, are a highly conserved and dynamically regulated set of cassette exons. They have key roles in nervous system development and function, as evidenced by recent results demonstrating the impact of microexons on behaviour and cognition. However, microexons are often overlooked due to the difficulty of detecting them using standard RNA-seq aligners. RESULTS Here, we present MicroExonator, a novel pipeline for reproducible de novo discovery and quantification of microexons. We process 289 RNA-seq datasets from eighteen mouse tissues corresponding to nine embryonic and postnatal stages, providing the most comprehensive survey of microexons available for mice. We detect 2984 microexons, 332 of which are differentially spliced throughout mouse embryonic brain development, including 29 that are not present in mouse transcript annotation databases. Unsupervised clustering of microexons based on their inclusion patterns segregates brain tissues by developmental time, and further analysis suggests a key function for microexons in axon growth and synapse formation. Finally, we analyse single-cell RNA-seq data from the mouse visual cortex, and for the first time, we report differential inclusion between neuronal subpopulations, suggesting that some microexons could be cell type-specific. CONCLUSIONS MicroExonator facilitates the investigation of microexons in transcriptome studies, particularly when analysing large volumes of data. As a proof of principle, we use MicroExonator to analyse a large collection of both mouse bulk and single-cell RNA-seq datasets. The analyses enabled the discovery of previously uncharacterized microexons, and our study provides a comprehensive microexon inclusion catalogue during mouse development.
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Affiliation(s)
- Guillermo E Parada
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Roberto Munita
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ilias Georgakopoulos-Soares
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Hugo J R Fernandes
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Veronika R Kedlian
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Emmanouil Metzakopian
- UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Maria Estela Andres
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eric A Miska
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
| | - Martin Hemberg
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
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5
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Microexons: at the nexus of nervous system development, behaviour and autism spectrum disorder. Curr Opin Genet Dev 2020; 65:22-33. [PMID: 32535349 DOI: 10.1016/j.gde.2020.03.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 12/19/2022]
Abstract
The discovery and characterization of a network of highly conserved neuronal microexons has provided fundamental new insight into mechanisms underlying nervous system development and function, as well as an important basis for pathway convergence in autism spectrum disorder. In the past few years, considerable progress has been made in comprehensively determining the repertoires of factors that control neuronal microexons. These results have illuminated molecular mechanisms that activate the splicing of microexons, including those that control gene expression programs critical for neurogenesis, as well as synaptic protein translation and neuronal activity. Remarkably, individual disruption of specific microexons in these pathways results in autism-like phenotypes and cognitive impairment in mice. This review discusses these findings and their implications for delivering new therapeutic strategies for neurological disorders.
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6
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Padmanabhan S, Burke RE. Induction of axon growth in the adult brain: A new approach to restoration in Parkinson's disease. Mov Disord 2017; 33:62-70. [PMID: 29205486 DOI: 10.1002/mds.27209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Affiliation(s)
| | - Robert E Burke
- Department of Neurology, Columbia University, New York, New York, USA.,Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
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7
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Kjaergaard M, Kragelund BB. Functions of intrinsic disorder in transmembrane proteins. Cell Mol Life Sci 2017; 74:3205-3224. [PMID: 28601983 PMCID: PMC11107515 DOI: 10.1007/s00018-017-2562-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022]
Abstract
Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine receptors. The functions of the disordered regions are many and varied. We will discuss selected examples including: (1) Organization of receptors, kinases, phosphatases and second messenger sources into signaling complexes. (2) Modulation of the membrane-embedded domain function by ball-and-chain like mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding protein disorder.
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Affiliation(s)
- Magnus Kjaergaard
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- The Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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8
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Gumy LF, Katrukha EA, Grigoriev I, Jaarsma D, Kapitein LC, Akhmanova A, Hoogenraad CC. MAP2 Defines a Pre-axonal Filtering Zone to Regulate KIF1- versus KIF5-Dependent Cargo Transport in Sensory Neurons. Neuron 2017; 94:347-362.e7. [PMID: 28426968 DOI: 10.1016/j.neuron.2017.03.046] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 01/17/2017] [Accepted: 03/29/2017] [Indexed: 11/15/2022]
Abstract
Polarized cargo transport is essential for neuronal function. However, the minimal basic components required for selective cargo sorting and distribution in neurons remain elusive. We found that in sensory neurons the axon initial segment is largely absent and that microtubule-associated protein 2 (MAP2) defines the cargo-filtering zone in the proximal axon. Here, MAP2 directs axonal cargo entry by coordinating the activities of molecular motors. We show that distinct kinesins differentially regulate cargo velocity: kinesin-3 drives fast axonal cargo trafficking, while kinesin-1 slows down axonal cargo transport. MAP2 inhibits "slow" kinesin-1 motor activity and allows kinesin-3 to drive robust cargo transport from the soma into the axon. In the distal axon, the inhibitory action of MAP2 decreases, leading to regained kinesin-1 activity and vesicle distribution. We propose that selective axonal cargo trafficking requires the MAP2-defined pre-axonal filtering zone and the ability of cargos to switch between distinct kinesin motor activities.
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Affiliation(s)
- Laura F Gumy
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Ilya Grigoriev
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Dick Jaarsma
- Department of Neuroscience, Erasmus Medical Center, 3015 CE Rotterdam, the Netherlands
| | - Lukas C Kapitein
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
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9
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Cornejo VH, Luarte A, Couve A. Global and local mechanisms sustain axonal proteostasis of transmembrane proteins. Traffic 2017; 18:255-266. [PMID: 28220989 DOI: 10.1111/tra.12472] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/02/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022]
Abstract
The control of neuronal protein homeostasis or proteostasis is tightly regulated both spatially and temporally, assuring accurate and integrated responses to external or intrinsic stimuli. Local or autonomous responses in dendritic and axonal compartments are crucial to sustain function during development, physiology and in response to damage or disease. Axons are responsible for generating and propagating electrical impulses in neurons, and the establishment and maintenance of their molecular composition are subject to extreme constraints exerted by length and size. Proteins that require the secretory pathway, such as receptors, transporters, ion channels or cell adhesion molecules, are fundamental for axonal function, but whether axons regulate their abundance autonomously and how they achieve this is not clear. Evidence supports the role of three complementary mechanisms to maintain proteostasis of these axonal proteins, namely vesicular transport, local translation and trafficking and transfer from supporting cells. Here, we review these mechanisms, their molecular machineries and contribution to neuronal function. We also examine the signaling pathways involved in local translation and their role during development and nerve injury. We discuss the relative contributions of a transport-controlled proteome directed by the soma (global regulation) versus a local-controlled proteome based on local translation or cell transfer (local regulation).
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Affiliation(s)
- Víctor Hugo Cornejo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Alejandro Luarte
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Andrés Couve
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
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10
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Ustianenko D, Weyn-Vanhentenryck SM, Zhang C. Microexons: discovery, regulation, and function. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28188674 DOI: 10.1002/wrna.1418] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 12/16/2022]
Abstract
The importance of RNA splicing in numerous cellular processes is well established. However, an underappreciated aspect is the ability of the spliceosome to recognize a set of very small (3-30 nucleotide, 1-10 amino acid) exons named microexons. Despite their small size, microexons and their regulation through alternative splicing have now been shown to play critical roles in protein and system function. Here we review the discovery of microexons over time and the mechanisms by which their splicing is regulated, including recent progress made through deep RNA sequencing. We also discuss the functional role of microexons in biology and disease. WIREs RNA 2017, 8:e1418. doi: 10.1002/wrna.1418 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Dmytro Ustianenko
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Sebastien M Weyn-Vanhentenryck
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
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11
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Samatov TR, Wicklein D, Tonevitsky AG. L1CAM: Cell adhesion and more. ACTA ACUST UNITED AC 2016; 51:25-32. [DOI: 10.1016/j.proghi.2016.05.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/20/2016] [Indexed: 12/17/2022]
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12
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Cell Adhesion Molecules and Ubiquitination-Functions and Significance. BIOLOGY 2015; 5:biology5010001. [PMID: 26703751 PMCID: PMC4810158 DOI: 10.3390/biology5010001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/02/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.
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13
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Itoh K, Fushiki S. The role of L1cam in murine corticogenesis, and the pathogenesis of hydrocephalus. Pathol Int 2015; 65:58-66. [DOI: 10.1111/pin.12245] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/21/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Kyoko Itoh
- Department of Pathology and Applied Neurobiology; Graduate School of Medical Science; Kyoto Prefectural University of Medicine; Kyoto Japan
| | - Shinji Fushiki
- Department of Pathology and Applied Neurobiology; Graduate School of Medical Science; Kyoto Prefectural University of Medicine; Kyoto Japan
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14
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Tonosaki M, Itoh K, Umekage M, Kishimoto T, Yaoi T, Lemmon VP, Fushiki S. L1cam is crucial for cell locomotion and terminal translocation of the Soma in radial migration during murine corticogenesis. PLoS One 2014; 9:e86186. [PMID: 24489698 PMCID: PMC3904877 DOI: 10.1371/journal.pone.0086186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 12/08/2013] [Indexed: 11/27/2022] Open
Abstract
L1cam (L1) is a cell adhesion molecule associated with a spectrum of human neurological diseases, the most well-known being X-linked hydrocephalus. Although we recently demonstrated that L1 plays an important role in neuronal migration during cortical histogenesis, the mechanisms of delayed migration have still not been clarified. In this study, we found that cell locomotion in the intermediate zone and terminal translocation in the primitive cortical zone (PCZ) were affected by L1-knockdown (L1-KD). Time-lapse analyses revealed that L1-KD neurons produced by in utero electroporation of shRNA targeting L1 (L1-shRNAs) molecules showed decreased locomotion velocity in the intermediate zone, compared with control neurons. Furthermore, L1-KD neurons showed longer and more undulated leading processes during translocation through the primitive cortical zone. The curvature index, a quantitative index for curvilinearity, as well as the length of the leading process, were increased, whereas the somal movement was decreased in L1-KD neurons during terminal translocation in the PCZ. These results suggest that L1 has a role in radial migration of cortical neurons.
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Affiliation(s)
- Madoka Tonosaki
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kyoko Itoh
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- * E-mail:
| | - Masafumi Umekage
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomokazu Kishimoto
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takeshi Yaoi
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Vance P. Lemmon
- The Miami Project to Cure Paralysis, University of Miami School of Medicine, Lois Pope LIFE Center, Miami, Florida, United States of America
| | - Shinji Fushiki
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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15
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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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16
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Abstract
Cell adhesion molecules of the immunoglobulin-super-family (IgSF-CAMs) do not only have a physical effect, mediating merely attachment between cell surfaces. For navigating axons, IgSF-CAMs also exert an instructive impact: Upon activation, they elicit intracellular signalling cascades in the tip of the axon, the growth cone, which regulate in a spatio-temporally concerted action both speed and direction of the axon. Density and distribution of IgSF-CAMs in the growth cone plasma membrane play important roles for the activation of IgSF-CAMs, their clustering, and the adhesive forces they acquire, as well as for the local restriction and effective propagation of their intracellular signals.
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17
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Kishimoto T, Itoh K, Umekage M, Tonosaki M, Yaoi T, Fukui K, Lemmon VP, Fushiki S. Downregulation of L1 perturbs neuronal migration and alters the expression of transcription factors in murine neocortex. J Neurosci Res 2012; 91:42-50. [PMID: 23073969 PMCID: PMC3533181 DOI: 10.1002/jnr.23141] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/15/2012] [Accepted: 08/21/2012] [Indexed: 01/12/2023]
Abstract
L1 is a cell adhesion molecule associated with a spectrum of human neurological diseases, the most well-known being X-linked hydrocephalus. L1 knockout (L1-KO) mice have revealed a variety of functions of L1 that were crucial in brain development in different brain regions. However; the function of L1 in neuronal migration during cortical histogenesis remains to be clarified. We therefore investigated the corticogenesis of mouse embryos in which L1 molecules were knocked down in selected neurons, by employing in utero electroporation with shRNAs targeting L1 (L1 shRNA). Although more than 50% of the cells transfected with no small hairpin RNA (shRNA; monster green fluorescent protein: MGFP only) vector at embryonic day 13 (E13) reached the cortical plate at E16, significantly fewer (27%) cells transfected with L1 shRNA migrated to the same extent. At E17, 22% of cells transfected with the MGFP-only vector were found in the intermediate zone, and significantly more (34%) cells transfected with L1 shRNA remained in the same zone. Furthermore, the directions of the leading process of neurons transfected with L1 shRNA became more dispersed compared with cells with the MGFP-only vector. In addition, two transcription factors expressed in the neurons, Satb2 and Tbr1, were shown to be reduced or aberrantly expressed in neurons transfected with L1 shRNA. These observations suggest that L1 plays an important role in regulating the locomotion and orientation of migrating neurons and the expression of transcription factors during neocortical development that might partially be responsible for the abnormal tract formation seen in L1-KO mice. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Tomokazu Kishimoto
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan
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Littner Y, Tang N, He M, Bearer CF. L1 cell adhesion molecule signaling is inhibited by ethanol in vivo. Alcohol Clin Exp Res 2012; 37:383-9. [PMID: 23050935 DOI: 10.1111/j.1530-0277.2012.01944.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/09/2012] [Indexed: 01/12/2023]
Abstract
BACKGROUND Fetal alcohol spectrum disorder is an immense public health problem. In vitro studies support the hypothesis that L1 cell adhesion molecule (L1) is a target for ethanol (EtOH) developmental neurotoxicity. L1 is critical for the development of the central nervous system. It functions through signal transduction leading to phosphorylation and dephosphorylation of tyrosines on its cytoplasmic domain. The function of L1 is also dependent on trafficking through lipid rafts (LRs). Our hypothesis is that L1 is a target for EtOH neurotoxicity in vivo. Our objective is to demonstrate changes in L1 phosphorylation/dephosphorylation and LR association in vivo. METHODS Rat pups on postnatal day 6 are administered 4.5, 5.25, and 6 g/kg of EtOH divided into 2 doses 2 hours apart, then killed. Cerebella are rapidly frozen for assay. Blood is analyzed for blood EtOH concentration. L1 tyrosine phosphorylation is determined by immunoprecipitation and dephosphorylation of tyrosine 1176 determined by immunoblot. LRs are isolated by sucrose density gradient, and the distribution of L1 in LRs is determined. RESULTS EtOH at all doses reduced the relative amount of Y1176 dephosphorylation as well as the relative amount of L1 phosphorylated on other tyrosines. The proportion of L1 present in LRs is significantly increased in pups who received 6 g/kg EtOH compared to intubated controls. CONCLUSIONS L1 is a target for EtOH developmental neurotoxicity in vivo.
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Affiliation(s)
- Yoav Littner
- Department of Neuroscience, Lerner Research Institute, Children's Hospital, The Cleveland Clinic, Cleveland, Ohio, USA
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19
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Dai J, Dalal JS, Thakar S, Henkemeyer M, Lemmon VP, Harunaga JS, Schlatter MC, Buhusi M, Maness PF. EphB regulates L1 phosphorylation during retinocollicular mapping. Mol Cell Neurosci 2012; 50:201-10. [PMID: 22579729 DOI: 10.1016/j.mcn.2012.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/10/2012] [Accepted: 05/02/2012] [Indexed: 01/24/2023] Open
Abstract
Interaction of the cell adhesion molecule L1 with the cytoskeletal adaptor ankyrin is essential for topographic mapping of retinal ganglion cell (RGC) axons to synaptic targets in the superior colliculus (SC). Mice mutated in the L1 ankyrin-binding motif (FIGQY(1229)H) display abnormal mapping of RGC axons along the mediolateral axis of the SC, resembling mouse mutant phenotypes in EphB receptor tyrosine kinases. To investigate whether L1 functionally interacts with EphBs, we investigated the role of EphB kinases in phosphorylating L1 using a phospho-specific antibody to the tyrosine phosphorylated FIGQY(1229) motif. EphB2, but not an EphB2 kinase dead mutant, induced tyrosine phosphorylation of L1 at FIGQY(1229) and perturbed ankyrin recruitment to the membrane in L1-transfected HEK293 cells. Src family kinases mediated L1 phosphorylation at FIGQY(1229) by EphB2. Other EphB receptors that regulate medial-lateral retinocollicular mapping, EphB1 and EphB3, also mediated phosphorylation of L1 at FIGQY(1229). Tyrosine(1176) in the cytoplasmic domain of L1, which regulates AP2/clathrin-mediated endocytosis and axonal trafficking, was not phosphorylated by EphB2. Accordingly mutation of Tyr(1176) to Ala in L1-Y(1176)A knock-in mice resulted in normal retinocollicular mapping of ventral RGC axons. Immunostaining of the mouse SC during retinotopic mapping showed that L1 colocalized with phospho-FIGQY in RGC axons in retinorecipient layers. Immunoblotting of SC lysates confirmed that L1 was phosphorylated at FIGQY(1229) in wild type but not L1-FIGQY(1229)H (L1Y(1229)H) mutant SC, and that L1 phosphorylation was decreased in the EphB2/B3 mutant SC. Inhibition of ankyrin binding in L1Y(1229)H mutant RGCs resulted in increased neurite outgrowth compared to WT RGCs in retinal explant cultures, suggesting that L1-ankyrin binding serves to constrain RGC axon growth. These findings are consistent with a model in which EphB kinases phosphorylate L1 at FIGQY(1229) in retinal axons to modulate L1-ankyrin binding important for mediolateral retinocollicular topography.
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Affiliation(s)
- Jinxia Dai
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
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Thelen K, Maier B, Faber M, Albrecht C, Fischer P, Pollerberg GE. Translation of the cell adhesion molecule ALCAM in axonal growth cones – regulation and functional importance. J Cell Sci 2012; 125:1003-14. [DOI: 10.1242/jcs.096149] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ALCAM is a cell adhesion molecule that is present on extending axons and has been shown to be crucial for elongation and navigation of retinal ganglion cell (RGC) axons. In the present study, we show that ALCAM mRNA is present in axonal growth cones of RGCs in vivo and in vitro, and that translation of ALCAM occurs in RGC growth cones separated from their soma. This growth cone translation is regulated by the 3′-untranslated region (3′-UTR) of ALCAM and depends on the activity of the kinases ERK and TOR (target of rapamycin). We also investigated the impact of the growth cone translation of ALCAM on axonal functions. Growth cone translation of ALCAM is crucial for the enhanced elongation of axons extending in contact with ALCAM protein. The local translation of ALCAM in the growth cone is able to rapidly counterbalance experimentally induced ALCAM internalization, thereby contributing to the maintenance of constant ALCAM levels in the plasma membrane. Assays where RGC axons have the choice to grow on laminin or both ALCAM and laminin – as is the case in the developing retina – reveal that the axonal preference for ALCAM-containing lanes depends on translation of ALCAM in growth cones. Taken together, these results show for the first time that translation of a cell adhesion molecule in growth cones, as well as the impact of this local translation on the behavior of axon and growth cone.
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Affiliation(s)
- Karsten Thelen
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
| | - Bettina Maier
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
| | - Marc Faber
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
| | - Christian Albrecht
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
| | - Paulina Fischer
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
| | - G. Elisabeth Pollerberg
- Department of Developmental Neurobiology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
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Abstract
Axon regeneration is a fundamental problem facing neuroscientists and clinicians. Failure of axon regeneration is caused by both extrinsic and intrinsic mechanisms. New techniques to examine gene expression such as Next Generation Sequencing of the Transcriptome (RNA-Seq) drastically increase our knowledge of both gene expression complexity (RNA isoforms) and gene expression regulation. By utilizing RNA-Seq, gene expression can now be defined at the level of isoforms, an essential step for understanding the mechanisms governing cell identity, growth and ultimately cellular responses to injury and disease.
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Affiliation(s)
- Jessica K Lerch
- The Miami Project to Cure Paralysis, The University of Miami, Miami, FL, USA
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22
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Winckler B, Yap CC. Endocytosis and endosomes at the crossroads of regulating trafficking of axon outgrowth-modifying receptors. Traffic 2011; 12:1099-108. [PMID: 21535338 DOI: 10.1111/j.1600-0854.2011.01213.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In neurons, many receptors must be localized correctly to axons or dendrites for proper function. During development, receptors for nerve growth and guidance are targeted to axons and localized to growth cones where receptor activation by ligands results in promotion or inhibition of axon growth. Signaling outcomes downstream of ligand binding are determined by the location, levels and residence times of receptors on the neuronal plasma membrane. Therefore, the mechanisms controlling the trafficking of these receptors are crucial to the proper wiring of circuits. Membrane proteins accumulate on the axonal surface by multiple routes, including polarized sorting in the trans Golgi network, sorting in endosomes and removal by endocytosis. Endosomes also play important roles in the signaling pathways for both growth-promoting and -inhibiting molecules: signaling endosomes derived from endocytosis are important for signaling from growth cones to cell bodies. Growth-promoting neurotrophins and growth-inhibiting Nogo-A can use EHD4/Pincher-dependent endocytosis at the growth cone for their respective retrograde signaling. In addition to retrograde transport of endosomes, anterograde transport to axons in endosomes also occurs for several receptors, including the axon outgrowth-promoting cell adhesion molecule L1/NgCAM and TrkA. L1/NgCAM also depends on EHD4/Pincher-dependent endocytosis for its axonal polarization. In this review, we will focus on receptors whose trafficking has been reported to be modulated by the EHD4/Pincher family of endosomal regulators, namely L1/NgCAM, Trk and Nogo-A. We will first summarize the pathways underlying the axonal transport of these proteins and then discuss the potential roles of EHD4/Pincher in mediating their endocytosis.
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Affiliation(s)
- Bettina Winckler
- Department of Neuroscience, University of Virginia Medical School, MR4-6115, 409 Lane Road Ext., Charlottesville, VA 22936, USA.
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23
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Rehnberg M, Jonasson J, Gunnarsson C. Novel L1CAM splice site mutation in a young male with L1 syndrome. Am J Med Genet A 2010; 155A:439-41. [PMID: 21271669 DOI: 10.1002/ajmg.a.33803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 10/18/2010] [Indexed: 01/21/2023]
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Ramser EM, Wolters G, Dityateva G, Dityatev A, Schachner M, Tilling T. The 14-3-3ζ protein binds to the cell adhesion molecule L1, promotes L1 phosphorylation by CKII and influences L1-dependent neurite outgrowth. PLoS One 2010; 5:e13462. [PMID: 20976158 PMCID: PMC2956685 DOI: 10.1371/journal.pone.0013462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 09/24/2010] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The cell adhesion molecule L1 is crucial for mammalian nervous system development. L1 acts as a mediator of signaling events through its intracellular domain, which comprises a putative binding site for 14-3-3 proteins. These regulators of diverse cellular processes are abundant in the brain and preferentially expressed by neurons. In this study, we investigated whether L1 interacts with 14-3-3 proteins, how this interaction is mediated, and whether 14-3-3 proteins influence the function of L1. METHODOLOGY/PRINCIPAL FINDINGS By immunoprecipitation, we demonstrated that 14-3-3 proteins are associated with L1 in mouse brain. The site of 14-3-3 interaction in the L1 intracellular domain (L1ICD), which was identified by site-directed mutagenesis and direct binding assays, is phosphorylated by casein kinase II (CKII), and CKII phosphorylation of the L1ICD enhances binding of the 14-3-3 zeta isoform (14-3-3ζ). Interestingly, in an in vitro phosphorylation assay, 14-3-3ζ promoted CKII-dependent phosphorylation of the L1ICD. Given that L1 phosphorylation by CKII has been implicated in L1-triggered axonal elongation, we investigated the influence of 14-3-3ζ on L1-dependent neurite outgrowth. We found that expression of a mutated form of 14-3-3ζ, which impairs interactions of 14-3-3ζ with its binding partners, stimulated neurite elongation from cultured rat hippocampal neurons, supporting a functional connection between L1 and 14-3-3ζ. CONCLUSIONS/SIGNIFICANCE Our results suggest that 14-3-3ζ, a novel direct binding partner of the L1ICD, promotes L1 phosphorylation by CKII in the central nervous system, and regulates neurite outgrowth, an important biological process triggered by L1.
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Affiliation(s)
- Elisa M. Ramser
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
| | - Gerrit Wolters
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
| | - Galina Dityateva
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
- Department of Neuroscience and Brain Technologies, Italian Institute of Technology, Genova, Italy
| | - Alexander Dityatev
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
- Department of Neuroscience and Brain Technologies, Italian Institute of Technology, Genova, Italy
| | - Melitta Schachner
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
| | - Thomas Tilling
- Zentrum für Molekulare Neurobiologie Hamburg, University of Hamburg, Hamburg, Germany
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25
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Nakamura Y, Lee S, Haddox CL, Weaver EJ, Lemmon VP. Role of the cytoplasmic domain of the L1 cell adhesion molecule in brain development. J Comp Neurol 2010; 518:1113-32. [PMID: 20127821 DOI: 10.1002/cne.22267] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mutations in the human L1CAM gene cause X-linked hydrocephalus and MASA (Mental retardation, Aphasia, Shuffling gait, Adducted thumbs) syndrome. In vitro studies have shown that the L1 cytoplasmic domain (L1CD) is involved in L1 trafficking, neurite branching, signaling, and interactions with the cytoskeleton. L1cam knockout (L1(KO)) mice have hydrocephalus, a small cerebellum, hyperfasciculation of corticothalamic tracts, and abnormal peripheral nerves. To explore the function of the L1CD, we made three new mice lines in which different parts of the L1CD have been altered. In all mutant lines L1 protein is expressed and transported into the axon. Interestingly, these new L1CD mutant lines display normal brain morphology. However, the expression of L1 protein in the adult is dramatically reduced in the two L1CD mutant lines that lack the ankyrin-binding region and they show defects in motor function. Therefore, the L1CD is not responsible for the major defects observed in L1(KO) mice, yet it is required for continued L1 protein expression and motor function in the adult.
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Affiliation(s)
- Yukiko Nakamura
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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26
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Chen MM, Lee CY, Leland HA, Lin GY, Montgomery AM, Silletti S. Inside-out regulation of L1 conformation, integrin binding, proteolysis, and concomitant cell migration. Mol Biol Cell 2010; 21:1671-85. [PMID: 20335502 PMCID: PMC2869374 DOI: 10.1091/mbc.e09-10-0900] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The ectodomain structure and function of the neural cell adhesion molecule L1 is shown to be regulated by the intracellular phosphorylation of a novel threonine, T1172. In pancreatic cancer cells, T1172 exhibits steady-state saturated phosphorylation, an event regulated by CKII and PKC, and which further regulates cell migration. Previous reports on the expression of the cell adhesion molecule L1 in pancreatic ductal adenocarcinoma (PDAC) cells range from absent to high. Our data demonstrate that L1 is expressed in poorly differentiated PDAC cells in situ and that threonine-1172 (T1172) in the L1 cytoplasmic domain exhibits steady-state saturated phosphorylation in PDAC cells in vitro and in situ. In vitro studies support roles for casein kinase II and PKC in this modification, consistent with our prior studies using recombinant proteins. Importantly, T1172 phosphorylation drives, or is associated with, a change in the extracellular structure of L1, consistent with a potential role in regulating the shift between the closed conformation and the open, multimerized conformation of L1. We further demonstrate that these distinct conformations exhibit differential binding to integrins αvβ3 and αvβ5 and that T1172 regulates cell migration in a matrix-specific manner and is required for a disintegrin and metalloproteinase-mediated shedding of the L1 ectodomain that has been shown to regulate cell migration. These data define a specific role for T1172 of L1 in regulating aspects of pancreatic adenocarcinoma cell phenotype and suggest the need for further studies to elucidate the specific ramifications of L1 expression and T1172 phosphorylation in the pathobiology of pancreatic cancer.
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Affiliation(s)
- Maxine M Chen
- Moores Cancer Center and Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA
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27
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Chen MM, Leland HA, Lee CY, Silletti S. Tyrosine and serine phosphorylation regulate the conformation and subsequent threonine phosphorylation of the L1 cytoplasmic domain. Biochem Biophys Res Commun 2009; 389:257-64. [PMID: 19720049 DOI: 10.1016/j.bbrc.2009.08.143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 08/22/2009] [Indexed: 12/20/2022]
Abstract
Previously we identified threonine-1172 (T1172) in the cytoplasmic domain of the cell adhesion molecule L1 as phosphorylated in pancreatic cancer cells. Although both CKII- and PKC-blockade suppressed this modification, only CKII was capable of phosphorylating T1172 of a recombinant L1 cytoplasmic domain, suggesting the requirement for additional events to facilitate availability of T1172 to PKC. In this study, we demonstrate that the region around T1172 exists in distinct conformations based on both T1172 phosphorylation and the integrity of surrounding residues. We further demonstrate the role of membrane-proximal and membrane-distal residues in regulating cytoplasmic domain conformation, and that modification of 3 of the 4 tyrosines in the L1 cytoplasmic domain promote conformational changes that facilitate other events. In particular, phenylalanine-substitution of tyrosine-1151 or tyrosine-1229 promote opening up of the cytoplasmic domain in a manner that facilitates phosphorylation of the other 3 tyrosines, as well as phosphorylation of T1172 by PKCalpha. Importantly, we show that phosphorylation of serine-1181 is required for T1172 phosphorylation by CKII. These data define a specific role for secondary structure in regulating the availability of T1172 that facilitates phosphorylation by PKC.
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Affiliation(s)
- Maxine M Chen
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0803, USA
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28
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Bel C, Oguievetskaia K, Pitaval C, Goutebroze L, Faivre-Sarrailh C. Axonal targeting of Caspr2 in hippocampal neurons via selective somatodendritic endocytosis. J Cell Sci 2009; 122:3403-13. [PMID: 19706678 DOI: 10.1242/jcs.050526] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Contactin-associated protein 2 (Caspr2) is a neuronal membrane protein that is mutated in autism and related disorders. Although it is highly enriched at juxtaparanodes of Ranvier where it is essential for Shaker-type K(+) channel clustering, little is known about its function and regulation. In the present study, we examined the polarized expression of Caspr2 in hippocampal neurons using extracellular hemagglutinin (HA)-tagged Caspr2 constructs. We found that Caspr2 was targeted to the axonal surface, but colocalized with early endosomes in the somatodendritic compartment. The inhibition of endocytosis using a Dynamin-1 mutant or treatment with Dynasore prevented Caspr2 internalization from the dendrites and cell body. We identified a short sequence included into the 4.1B-binding domain that is required for the endocytosis of Caspr2. This sequence contains a protein kinase C (PKC) substrate motif on Thr1292, and point mutation of this residue or treatment with a PKC inhibitor prevented the somatodendritic internalization of Caspr2. Thus, the PKC-dependent trafficking of Caspr2 underlies its polarized expression in hippocampal neurons.
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Affiliation(s)
- Christophe Bel
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 6231 CNRS, Université de la Méditerranée Aix-Marseille II, Marseille 13916, France
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29
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Zhang Q, Wang F, Cao J, Shen Y, Huang Q, Bao L, Zhu X. Nudel promotes axonal lysosome clearance and endo-lysosome formation via dynein-mediated transport. Traffic 2009; 10:1337-49. [PMID: 19522757 DOI: 10.1111/j.1600-0854.2009.00945.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Axonal transport is critical for neuronal function and survival. Cytoplasmic dynein and its accessory complex dynactin form a microtubule minus end-directed motor in charge of retrograde transport. In this study, we show that Nudel, a dynein regulator, was highly expressed in dorsal root ganglion (DRG) neurons. Microinjection of anti-Nudel antibody into cultured DRG neurons abolished retrograde transport of membranous organelles in the axon and led to dispersions of Golgi cisternae in the soma. As a result, lysosomes, which are normally enriched in the soma, moved persistently into and thus accumulated in axons. Endo-lysosome formation was also markedly delayed. As anterograde motility of mitochondria was not inhibited, the antibody apparently did not abolish retrograde transport by destructing axonal microtubule tracks. Similar results were obtained by microinjecting N-terminal Nudel, anti-dynein antibody or a p150(Glued) mutant capable of abrogating the dynein-dynactin association. These results indicate a critical role of Nudel in dynein-mediated axonal transport. Moreover, the effects of dynein on endolysosome formation and regional sequestration of lysosomes may contribute to defects in the endocytic pathway seen in neurons of patients or animals with malfunction of dynein.
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Affiliation(s)
- Qiangge Zhang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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30
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Yeaney NK, He M, Tang N, Malouf AT, O'Riordan MA, Lemmon V, Bearer CF. Ethanol inhibits L1 cell adhesion molecule tyrosine phosphorylation and dephosphorylation and activation of pp60(src). J Neurochem 2009; 110:779-90. [PMID: 19457108 DOI: 10.1111/j.1471-4159.2009.06143.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fetal alcohol syndrome is a leading cause of mental retardation. The neuropathology found in patients with fetal alcohol syndrome overlaps with those with mutations in the gene for cell adhesion molecule (L1). We have previously shown that L1-mediated neurite outgrowth and L1 activation of extracellular receptor kinases 1/2 are inhibited at low concentrations of ethanol. One possible mechanism for this effect is through disruption of a tyrosine-based sorting signal, Y(1176)RSLE, on the cytoplasmic domain of L1. Our goal was to determine if ethanol inhibited the sorting signal or its phosphorylation state. Using cerebellar granule neurons and dorsal root ganglion neurons, we found that ethanol had no effect on L1 distribution to the growth cone or its ability to be expressed on the cell surface as determined by confocal microscopy. In cerebellar granule neurons, clustering of L1 resulted in increased dephosphorylation of Y(1176), increased L1 tyrosine phosphorylation, and an increase in the activation of pp60(src) as measured by immunoblot. All changes were inhibited by 25 mM ethanol. Using PP2 to inhibit pp60(src) activation resulted in inhibition of increases in L1 tyrosine and extracellular receptor kinases 1/2 phosphorylation, and Y(1176) dephosphorylation. We conclude that ethanol disrupts L1 trafficking/signaling following its expression on the surface of the growth cone, and prior to its activation of pp60(src).
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Abstract
The L1 family of CAMs (cell adhesion molecules) has long aroused the interest of researchers, but primarily the extracellular interactions of these proteins have been elucidated. More recently, attention has turned to the intracellular signalling potentiated by transmembrane proteins and the cytoplasmic proteins with which they can interact. The present review brings up to date the current body of published knowledge for the intracellular interactions of L1-CAM family proteins and the potential importance of these interactions for the mechanisms of L1-CAM action.
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32
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Allen J, Chilton JK. The specific targeting of guidance receptors within neurons: who directs the directors? Dev Biol 2008; 327:4-11. [PMID: 19121301 DOI: 10.1016/j.ydbio.2008.12.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 11/27/2008] [Accepted: 12/09/2008] [Indexed: 02/04/2023]
Abstract
Guidance molecules present in both axonal and dendritic growth cones mediate neuronal responses to extracellular cues thereby ensuring correct neurite pathfinding and development of the nervous system. Little is known though about the mechanisms employed by neurons to deliver these receptors, specifically and efficiently, to the extending growth cone. A deeper understanding of this process is crucial if guidance receptors are to be manipulated to promote nervous system repair. Studies in other polarised cells, notably epithelial, have elucidated fundamental routes to the intracellular segregation of molecules mediated by endosomal pathways. Due to their extreme complexity and specialisation, neurons appear to have built upon these generic systems to evolve sophisticated trafficking networks. A striking feature is the axon initial segment which acts like a valve to tightly regulate the flux of molecules both entering and leaving the axon. Once in the growth cone, further controls operate to enhance the retention or rejection, as appropriate, of membrane receptors. We discuss the current state of knowledge regarding the intracellular trafficking of axon guidance receptors and how this relates to their developmental roles. We highlight the various facets still to be properly elucidated and by building on existing data regarding neuronal polarity and intracellular sorting mechanisms suggest ways to fill these gaps.
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Affiliation(s)
- James Allen
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Research Way, Plymouth PL6 8BU, UK
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33
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Thelen K, Georg T, Bertuch S, Zelina P, Pollerberg GE. Ubiquitination and endocytosis of cell adhesion molecule DM-GRASP regulate its cell surface presence and affect its role for axon navigation. J Biol Chem 2008; 283:32792-801. [PMID: 18790729 DOI: 10.1074/jbc.m805896200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
DM-GRASP, cell adhesion molecule of the immunoglobulin superfamily, has been shown to promote growth and navigation of axons. We here demonstrate that clustering of DM-GRASP in the plasma membrane induces its rapid internalization via dynamin- and clathrin-dependent endocytosis, which is controlled by phosphatidylinositol 3-kinase and mitogen-activated protein kinase ERK. The clustering of DM-GRASP activates ERK; the intensity and duration of ERK activation by DM-GRASP do not depend on rapid clathrin-mediated internalization of DM-GRASP. Moreover, the preference of retinal ganglion cell axons for DM-GRASP-coated micro-lanes requires clathrin-mediated endocytosis for the appropriate axonal turning reactions at substrate borders. Because the intracellular domain of DM-GRASP does not contain motifs for direct interactions with the endocytosis machinery, we performed a yeast two-hybrid screen to identify intracellular proteins mediating the uptake of DM-GRASP and isolated ubiquitin. Immunoprecipitation of DM-GRASP coexpressed with ubiquitin revealed that one or two ubiquitin(s) are attached to the intracellular domain of cell surface-resident DM-GRASP. Furthermore, elevated ubiquitination levels result in a decrease of cell surface-resident DM-GRASP as well as in the amount of total DM-GRASP. The endocytosis rate is not affected, but the delivery to multivesicular bodies is increased, indicating that DM-GRASP ubiquitination enhances its sorting into the degradation pathway. Together, our data show that ubiquitination and endocytosis of DM-GRASP in concert regulate its cell surface concentration, which is crucial for its function in axon navigation.
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Affiliation(s)
- Karsten Thelen
- Department of Developmental Neurobiology, University of Heidelberg, D-69120 Heidelberg, Germany
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Wang PY, Seabold GK, Wenthold RJ. Synaptic adhesion-like molecules (SALMs) promote neurite outgrowth. Mol Cell Neurosci 2008; 39:83-94. [PMID: 18585462 DOI: 10.1016/j.mcn.2008.05.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/12/2008] [Accepted: 05/26/2008] [Indexed: 11/15/2022] Open
Abstract
SALMs are a family of five adhesion molecules whose expression is largely restricted to the CNS. Initial reports showed that SALM1 functions in neurite outgrowth while SALM2 is involved in synapse formation. To investigate the function of SALMs in detail, we asked if all five are involved in neurite outgrowth. Expression of epitope-tagged proteins in cultured hippocampal neurons showed that SALMs are distributed throughout neurons, including axons, dendrites, and growth cones. Over-expression of each SALM resulted in enhanced neurite outgrowth, but with different phenotypes. Neurite outgrowth could be reduced by applying antibodies targeting the extracellular leucine rich regions of SALMs and with RNAi. Through over-expression of deletion constructs, we found that the C-terminal PDZ binding domains of SALMs 1-3 are required for most aspects of neurite outgrowth. In addition, by using a chimera of SALMs 2 and 4, we found that the N-terminus is also involved in neurite outgrowth.
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Affiliation(s)
- Philip Y Wang
- Laboratory of Neurochemistry, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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Yap CC, Nokes RL, Wisco D, Anderson E, Fölsch H, Winckler B. Pathway selection to the axon depends on multiple targeting signals in NgCAM. J Cell Sci 2008; 121:1514-25. [PMID: 18411247 DOI: 10.1242/jcs.022442] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Similar to most differentiated cells, both neurons and epithelial cells elaborate distinct plasma membrane domains that contain different membrane proteins. We have previously shown that the axonal cell-adhesion molecule L1/NgCAM accumulates on the axonal surface by an indirect transcytotic pathway via somatodendritic endosomes. MDCK epithelial cells similarly traffic NgCAM to the apical surface by transcytosis. In this study, we map the signals in NgCAM required for routing via the multi-step transcytotic pathway. We identify both a previously mapped tyrosine-based signal as a sufficient somatodendritic targeting signal, as well as a novel axonal targeting signal in the cytoplasmic tail of NgCAM. The axonal signal is glycine and serine rich, but only the glycine residues are required for activity. The somatodendritic signal is cis-dominant and needs to be inactivated in order for the axonal signal to be executed. Additionally, we show that the axonal cytoplasmic signal promotes apical targeting in MDCK cells. Transcytosis of NgCAM to the axon thus requires the sequential regulated execution of multiple targeting signals.
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Affiliation(s)
- Chan Choo Yap
- University of Virginia Medical School, Department of Neuroscience, Charlottesville, VA 22908, USA
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36
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Yap CC, Wisco D, Kujala P, Lasiecka ZM, Cannon JT, Chang MC, Hirling H, Klumperman J, Winckler B. The somatodendritic endosomal regulator NEEP21 facilitates axonal targeting of L1/NgCAM. ACTA ACUST UNITED AC 2008; 180:827-42. [PMID: 18299352 PMCID: PMC2265569 DOI: 10.1083/jcb.200707143] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Correct targeting of proteins to axons and dendrites is crucial for neuronal function. We showed previously that axonal accumulation of the cell adhesion molecule L1/neuron-glia cell adhesion molecule (NgCAM) depends on endocytosis (Wisco, D., E.D. Anderson, M.C. Chang, C. Norden, T. Boiko, H. Folsch, and B. Winckler. 2003. J. Cell Biol. 162:1317–1328). Two endocytosis-dependent pathways to the axon have been proposed: transcytosis and selective retrieval/retention. We show here that axonal accumulation of L1/NgCAM occurs via nondegradative somatodendritic endosomes and subsequent anterograde axonal transport, which is consistent with transcytosis. Additionally, we identify the neuronal-specific endosomal protein NEEP21 (neuron-enriched endosomal protein of 21 kD) as a regulator of L1/NgCAM sorting in somatodendritic endosomes. Down-regulation of NEEP21 leads to missorting of L1/NgCAM to the somatodendritic surface as well as to lysosomes. Importantly, the axonal accumulation of endogenous L1 in young neurons is also sensitive to NEEP21 depletion. We propose that small endosomal carriers derived from somatodendritic recycling endosomes can serve to redistribute a distinct set of membrane proteins from dendrites to axons.
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Affiliation(s)
- Chan Choo Yap
- Department of Neuroscience, University of Virginia Medical School, Charlottesville, VA 22908, USA
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Diestel S, Schaefer D, Cremer H, Schmitz B. NCAM is ubiquitylated, endocytosed and recycled in neurons. J Cell Sci 2007; 120:4035-49. [DOI: 10.1242/jcs.019729] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The neural cell adhesion molecule NCAM plays an important role during neural development and in the adult brain. To study the intracellular trafficking of NCAM in neurons, two major isoforms, NCAM140 or NCAM180, were expressed in primary cortical neurons and in the rat B35 neuroblastoma cell line. NCAM was endocytosed and subsequently recycled to the plasma membrane, whereas only a minor fraction was degraded in lysosomes. In cortical neurons, endocytosis of NCAM was detected in the soma, neurites and growth cones in a developmentally regulated fashion. Furthermore, we found that NCAM is mono-ubiquitylated at the plasma membrane and endocytosis was significantly increased in cells overexpressing ubiquitin. Therefore, we propose that ubiquitylation represents an endocytosis signal for NCAM.
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Affiliation(s)
- Simone Diestel
- Institute of Animal Sciences, Department of Biochemistry, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany
| | - Daniel Schaefer
- Institute of Animal Sciences, Department of Biochemistry, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany
| | - Harold Cremer
- Institut de Biologie du Développement de Marseille-Luminy, UMR 6216, CNRS/Université de la Méditeranée, Campus de Luminy-case 907, 13288 Marseille cedex 9, France
| | - Brigitte Schmitz
- Institute of Animal Sciences, Department of Biochemistry, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany
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Nakata A, Kamiguchi H. Serine phosphorylation by casein kinase II controls endocytic L1 trafficking and axon growth. J Neurosci Res 2007; 85:723-34. [PMID: 17253643 DOI: 10.1002/jnr.21185] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The cell adhesion molecule L1 plays crucial roles in axon tract development. In vitro, L1 presented as a culture substrate stimulates axon elongation by binding to L1 expressed on the growth cone. In migrating growth cones, L1 is endocytosed via the AP-2/clathrin-mediated pathway at the central domain, followed by anterograde vesicular transport and recycling to the plasma membrane of the leading front. It has previously been shown that this endocytic trafficking of L1 is critical for axon elongation (Kamiguchi and Yoshihara [2001] J. Neurosci. 21:9194-9203). Adjacent to the AP-2 recognition site, the L1 cytoplasmic domain has a cluster of acidic amino acids containing Ser1181 that can be phosphorylated by casein kinase II (CKII; Wong et al. [1996a] J. Neurochem. 66:779-786). In this paper, we demonstrate that Ser1181 phosphorylation by CKII is implicated in both normal endocytic trafficking of L1 and L1-stimulated axon growth. Whereas L1 is sorted into transferrin-positive endosomes after endocytosis, pharmacological inhibition of CKII caused some population of L1 to be internalized into transferrin-negative compartments. Single-amino-acid mutations at Ser1181, which either prevent or mimic phosphorylation by CKII, caused similar missorting of internalized L1. Furthermore, dorsal root ganglion neurons that had been treated with a CKII inhibitor or transfected with the L1 mutants showed impaired ability to extend axons on an L1 substrate but not on other control substrates. These results demonstrate the novel role of CKII in L1-mediated axon elongation and stress the importance of functional linkage between L1 phosphorylation and L1 trafficking in migrating growth cones.
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Affiliation(s)
- Asuka Nakata
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, Wako, Saitama, Japan
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Nishimura K, Akiyama H, Komada M, Kamiguchi H. betaIV-spectrin forms a diffusion barrier against L1CAM at the axon initial segment. Mol Cell Neurosci 2007; 34:422-30. [PMID: 17223356 DOI: 10.1016/j.mcn.2006.11.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 11/15/2006] [Accepted: 11/20/2006] [Indexed: 11/17/2022] Open
Abstract
Axonal and somatodendritic plasma membranes of polarized neurons express distinct sets of functional molecules. It is known that the neuronal polarity can be maintained by a barrier that impedes diffusional mixing of membrane components between the two domains. Using betaIV-spectrin knockout mice, we demonstrate the involvement of this cytoskeletal protein in the formation of a barrier that selectively blocks lateral mobility of L1 cell adhesion molecule (L1CAM) at the axon initial segment of hippocampal neurons. We also show that the betaIV-spectrin-based barrier is required for the axon-specific distribution of L1CAM both in vitro and in vivo. The barrier activity against L1CAM may depend on direct interactions of L1CAM with ankyrinG, a protein binding to betaIV-spectrin, rather than on steric hindrance by other transmembrane proteins clustered at the axon initial segment. Our results highlight the role of betaIV-spectrin and ankyrinG as critical components of a selective barrier against L1CAM.
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Affiliation(s)
- Kazunari Nishimura
- Laboratory for Neuronal Growth Mechanisms, Brain Science Institute, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Schultheis M, Diestel S, Schmitz B. The role of cytoplasmic serine residues of the cell adhesion molecule L1 in neurite outgrowth, endocytosis, and cell migration. Cell Mol Neurobiol 2006; 27:11-31. [PMID: 17151951 DOI: 10.1007/s10571-006-9113-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 07/14/2006] [Indexed: 10/23/2022]
Abstract
1. The cell adhesion molecule L1 has been implicated in adhesion and migration of cells, in axon growth, guidance, and fasciculation, in myelination and synaptic plasticity. The cytoplasmic domain of neuronal L1 is highly conserved between species and has been shown to be phosphorylated at serine and tyrosine residues. 2. To investigate the significance of L1 serine phosphorylation, mutants of L1 were generated in which ser-1152, ser-1181, ser-1204, and ser-1248 were exchanged for leucine and rat B35 neuroblastoma cells were stably transfected with the L1-cDNA constructs. 3. Neurite outgrowth on poly-L-lysine (PLL) as substrate was determined either with or without differentiation into a neuronal phenotype with dbcAMP. In addition, antibody-induced endocytosis and cell migration were examined. 4. Our observations indicate that phosphorylation of single serine residues of the cytoplasmic domain of L1 contributes to neurite outgrowth through different mechanisms. Neurite growth is increased when ser-1152 or ser-1181 is replaced by a non-phosphorylatable leucine and decreased when ser-1204 or ser-1248 is mutated to leucine. Furthermore, mutation of ser-1181 to leucine results in strongly enhanced antibody-induced endocytosis of L1 and also in enhanced cell migration.
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Affiliation(s)
- M Schultheis
- Department of Biochemistry, Institute of Animal Sciences, University of Bonn, Katzenburgweg 9a, 53115, Bonn, Germany
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Chaudhry N, de Silva U, Smith GM. Cell adhesion molecule L1 modulates nerve-growth-factor-induced CGRP-IR fiber sprouting. Exp Neurol 2006; 202:238-49. [PMID: 16860320 DOI: 10.1016/j.expneurol.2006.06.001] [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: 03/07/2006] [Revised: 05/16/2006] [Accepted: 06/02/2006] [Indexed: 10/24/2022]
Abstract
Overexpression of nerve growth factor (NGF) using adenoviruses (Adts) after spinal cord injury induces extensive regeneration and sprouting of calcitonin-gene-related peptide immunoreactive (CGRP-IR) fibers, whereas overexpression of cell adhesion molecules (CAMs) has no effect on the normal distribution of these fibers. Interestingly, co-expression of cell adhesion molecule L1 and NGF significantly decreases (p<0.0001) CGRP-IR fiber sprouting within the spinal cord, when compared to NGF alone. Co-expression of cell adhesion molecules NCAM or N-cadherin had no effect on NGF-induced CGRP-IR fiber sprouting. These data demonstrate that reduced sprouting is specific to L1 co-expression and not other cell adhesion molecules. In vitro studies carried out to address potential mechanisms show that neurite outgrowth over astrocytes overexpressing L1 in the presence of NGF is comparable to controls, indicating that other factors present in vivo might be involved in the L1-mediated reduction in sprouting. One potential factor is semaphorin 3A (sema3A), which mediates growth cone collapse of CGRP-positive axons. Recent studies have shown that L1 is important in sema3A receptor signaling for cortical neurons. In our study, co-expression of sema3A indeed reduces neurite outgrowth from DRG neurons by about 40% on L1-expressing astrocytes. Based on these results, we hypothesize that overexpression of L1 potentiates sema3A signaling resulting in reduced sprouting.
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Affiliation(s)
- Nagarathnamma Chaudhry
- Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, KY 40536-0298, USA
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Nasu-Nishimura Y, Hayashi T, Ohishi T, Okabe T, Ohwada S, Hasegawa Y, Senda T, Toyoshima C, Nakamura T, Akiyama T. Role of the Rho GTPase-activating protein RICS in neurite outgrowth. Genes Cells 2006; 11:607-14. [PMID: 16716191 DOI: 10.1111/j.1365-2443.2006.00966.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The Rho family of small GTPases, including RhoA, Rac1 and Cdc42, are critical regulators of the actin cytoskeleton. In neuronal systems, Rho GTPase-activating proteins (RhoGAPs) and their substrates, Rho GTPases, have been implicated in regulating multiple processes in the morphological development of neurons, including axonal growth and guidance, dendritic elaboration and formation of synapses. RICS is mainly expressed in the brain and functions as a RhoGAP protein for Cdc42 and Rac1 in vitro. To examine the biological function of RICS, we disrupted the RICS gene in mice. RICS knockout mice developed normally and were fertile. However, when cultured in vitro, Cdc42 activity in RICS(-/-) neurons was higher than that in wild-type neurons. Consistent with this finding, hippocampal and cerebellar granule neurons derived from RICS(-/-) mice bore longer neurites than those from wild-type mice. These findings suggest that RICS plays an important role in neurite extension by regulating Cdc42 in vivo.
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Affiliation(s)
- Yukiko Nasu-Nishimura
- Laboratory of Molecular and Genetic Information, Institute for Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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Dirks P, Thomas U, Montag D. The cytoplasmic domain of NrCAM binds to PDZ domains of synapse-associated proteins SAP90/PSD95 and SAP97. Eur J Neurosci 2006; 24:25-31. [PMID: 16882004 DOI: 10.1111/j.1460-9568.2006.04899.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
NrCAM, a member of the L1 family of cell adhesion molecules, serves important functions during the development of the nervous system, e.g. in adhesion-dependent processes such as neurite outgrowth and axonal pathfinding. Complex homo- and heterophilic binding and several extracellular ligands of NrCAM have been described, but less is known about intracellular interaction partners. The cytoplasmic carboxy-terminus of NrCAM contains a typical sequence motif for binding to PDZ domains, making interactions with PDZ domain-containing scaffolding proteins quite conceivable. In this study, we identified specific interactions of the intracellular domain of NrCAM with class I PDZ domains of the membrane-associated guanylate kinases SAP90/PSD95 and SAP97. In contrast to NrCAM, the intracellular domains of the other mammalian L1 family molecules, e.g. L1, CHL1 and Neurofascin, did not interact with these PDZ domains. In transfected COS-7 cells, NrCAM-mediated recruitment of SAP97 to the plasma membrane was dependent on the PDZ binding motif. We show that NrCAM and SAP97 are colocalized, e.g. within photoreceptor terminals of the mammalian retina. In summary, our results confirm a functional PDZ domain binding motif at the carboxy-terminus of NrCAM and support potential functions of NrCAM during the assembly of highly organized protein complexes at the cell membrane.
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Affiliation(s)
- Petra Dirks
- Neurogenetics Research Group, Leibniz Institute for Neurobiology, Brenneckestr. 6, D-39118 Magdeburg, Germany
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Lindsley TA, Miller MW, Littner Y, Bearer CF. Signaling pathways regulating cell motility: a role in ethanol teratogenicity? Alcohol Clin Exp Res 2006; 30:1445-50. [PMID: 16899049 PMCID: PMC4199580 DOI: 10.1111/j.1530-0277.2006.00173.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This article summarizes the proceedings of a symposium presented at the 2005 annual meeting of the Research Society on Alcoholism in Santa Barbara, California. The organizer and chair was Tara A. Lindsley. The presentations were (1) Ethanol and Neuron Migration in the CNS, by Michael W. Miller; (2) Ethanol and L1-mediated Neurite Outgrowth, by Yoav Littner and Cynthia F. Bearer; and (3) Ethanol and Axon Guidance, by Tara A. Lindsley.
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Affiliation(s)
- Tara A Lindsley
- Center for Neuropharmacology & Neuroscience, MC-136, Albany Medical College, 47 New Scotland Ave., Albany NY 12208, USA.
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Cheng L, Lemmon S, Lemmon V. RanBPM is an L1-interacting protein that regulates L1-mediated mitogen-activated protein kinase activation. J Neurochem 2005; 94:1102-10. [PMID: 16000162 PMCID: PMC2424128 DOI: 10.1111/j.1471-4159.2005.03254.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A yeast two-hybrid screen using the last 28 amino acids of the cytoplasmic domain of the neural cell adhesion molecule L1 identified RanBPM as an L1-interacting protein. RanBPM associates with L1 in vivo and the N-terminal region of RanBPM (N-RanBPM), containing the SPRY domain, is sufficient for the interaction with L1 in a glutathione S-transferase pull-down assay. L1 antibody patching dramatically changes the subcellular localization of N-RanBPM in transfected COS cells. Overexpression of N-RanBPM in COS cells reduces L1-triggered extracellular signal-regulated kinase 1/2 activation by 50% and overexpression of N-RanBPM in primary neurons inhibits L1-mediated neurite outgrowth and branching. These data suggest that RanBPM is an adaptor protein that links L1 to the extracellular signal-regulated kinase/MAPK pathway.
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Affiliation(s)
- Ling Cheng
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
- The Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA
| | - Sandra Lemmon
- Department of Molecular and Cellular Pharmacology, University of Miami, Miami, Florida, USA
| | - Vance Lemmon
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
- The Miami Project to Cure Paralysis, University of Miami, Miami, Florida, USA
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Kanemura Y, Takuma Y, Kamiguchi H, Yamasaki M. First case of L1CAM gene mutation identified in MASA syndrome in Asia. Congenit Anom (Kyoto) 2005; 45:67-9. [PMID: 15904436 DOI: 10.1111/j.1741-4520.2005.00067.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here the first case of an L1CAM gene mutation identified in mental retardation, adducted thumbs, shuffling gait, and aphasia (MASA) syndrome in Japan. The patient was a 10-year-old boy with mild mental retardation, bilateral adducted thumbs and corpus callosum hypoplasia. His family had no history of MASA syndrome. The L1CAM gene contained a nonsense mutation (R1166X) in exon 26 in the cytoplasmic domain. No mutation was found in the extracellular and transmembrane domains of L1CAM. The abnormal development of axon tracts resulting in the corpus callosum hypoplasia and adducted thumbs appears to be caused by malfunction of the cytoplasmic domain of L1CAM.
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Affiliation(s)
- Yonehiro Kanemura
- Institute for Clinical Research, Osaka National Hospital, National Hospital Organization, Osaka 540-0006, Japan
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47
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Gutwein P, Stoeck A, Riedle S, Gast D, Runz S, Condon TP, Marmé A, Phong MC, Linderkamp O, Skorokhod A, Altevogt P. Cleavage of L1 in exosomes and apoptotic membrane vesicles released from ovarian carcinoma cells. Clin Cancer Res 2005; 11:2492-501. [PMID: 15814625 DOI: 10.1158/1078-0432.ccr-04-1688] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The L1 adhesion molecule (CD171) is overexpressed in human ovarian and endometrial carcinomas and is associated with bad prognosis. Although expressed as a transmembrane molecule, L1 is released from carcinoma cells in a soluble form. Soluble L1 is present in serum and ascites of ovarian carcinoma patients. We investigated the mode of L1 cleavage and the function of soluble L1. EXPERIMENTAL DESIGN We used ovarian carcinoma cell lines and ascites from ovarian carcinoma patients to analyze soluble L1 and L1 cleavage by Western blot analysis and ELISA. RESULTS We find that in ovarian carcinoma cells the constitutive cleavage of L1 proceeds in secretory vesicles. We show that apoptotic stimuli like C2-ceramide, staurosporine, UV irradiation, and hypoxic conditions enhance L1-vesicle release resulting in elevated levels of soluble L1. Constitutive cleavage of L1 is mediated by a disintegrin and metalloproteinase 10, but under apoptotic conditions multiple metalloproteinases are involved. L1 cleavage occurs in two types of vesicles with distinct density features: constitutively released vesicles with similarity to exosomes and apoptotic vesicles. Both types of L1-containing vesicles are present in the ascites fluids of ovarian carcinoma patients. Soluble L1 from ascites is a potent inducer of cell migration and can trigger extracellular signal-regulated kinase phosphorylation. CONCLUSIONS We suggest that tumor-derived vesicles may be an important source for soluble L1 that could regulate tumor cell function in an autocrine/paracrine fashion.
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Affiliation(s)
- Paul Gutwein
- Tumor Immunology Programme, D010, German Cancer Research Center, Heidelberg, Germany
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Cheng L, Lemmon V. Pathological missense mutations of neural cell adhesion molecule L1 affect neurite outgrowth and branching on an L1 substrate. Mol Cell Neurosci 2005; 27:522-30. [PMID: 15555929 DOI: 10.1016/j.mcn.2004.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Revised: 08/10/2004] [Accepted: 08/11/2004] [Indexed: 11/22/2022] Open
Abstract
A number of pathological missense mutations of L1CAM have been shown to disrupt L1-L1 homophilic binding and/or affect surface expression. To investigate whether these mutations disrupt L1-mediated neurite outgrowth, cerebellar neurons from L1 knockout mice are transfected with WT human L1 or L1 mutant constructs, and grown on an L1 substrate. Various parameters of neurite growth are quantified. Most L1 mutations do not affect neurite length significantly but several mutations cause a significant decrease in branching. Comparison of these data with data on L1 expression levels and homophilic binding strength show that changes in neurite growth cannot be simply explained by reductions in either of these parameters. Our results suggest that a coreceptor is involved in L1-mediated neurite outgrowth. Some pathological mutations have little effect on L1 mediated neurite growth, so it is unlikely that a failure of L1-mediated neurite outgrowth is the principle cause of brain defects in patients with L1 mutations.
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Affiliation(s)
- Ling Cheng
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
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49
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Kristiansen LV, Velasquez E, Romani S, Baars S, Berezin V, Bock E, Hortsch M, Garcia-Alonso L. Genetic analysis of an overlapping functional requirement for L1- and NCAM-type proteins during sensory axon guidance in Drosophila. Mol Cell Neurosci 2005; 28:141-52. [PMID: 15607949 DOI: 10.1016/j.mcn.2004.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 08/30/2004] [Accepted: 09/02/2004] [Indexed: 10/26/2022] Open
Abstract
L1- and NCAM-type cell adhesion molecules represent distinct protein families that function as specific receptors for different axon guidance cues. However, both L1 and NCAM proteins promote axonal growth by inducing neuronal tyrosine kinase activity and are coexpressed in subsets of axon tracts in arthropods and vertebrates. We have studied the functional requirements for the Drosophila L1- and NCAM-type proteins, Neuroglian (Nrg) and Fasciclin II (FasII), during postembryonic sensory axon guidance. The rescue of the Neuroglian loss-of-function (LOF) phenotype by transgenically expressed L1- and NCAM-type proteins demonstrates a functional interchangeability between these proteins in Drosophila photoreceptor pioneer axons, where both proteins are normally coexpressed. In contrast, the ectopic expression of Fasciclin II in mechanosensory neurons causes a strong enhancement of the axonal misguidance phenotype. Moreover, our findings demonstrate that this functionally redundant specificity to mediate axon guidance has been conserved in their vertebrate homologs, L1-CAM and NCAM.
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MESH Headings
- Animals
- Cell Adhesion Molecules, Neuronal/genetics
- Cell Adhesion Molecules, Neuronal/metabolism
- Cell Communication/genetics
- Drosophila/embryology
- Drosophila/genetics
- Drosophila/metabolism
- Drosophila Proteins
- Eye/cytology
- Eye/embryology
- Eye/metabolism
- Gene Expression Regulation, Developmental/genetics
- Growth Cones/metabolism
- Growth Cones/ultrastructure
- Mechanoreceptors/cytology
- Mechanoreceptors/embryology
- Mechanoreceptors/metabolism
- Nervous System/cytology
- Nervous System/embryology
- Nervous System/metabolism
- Neural Cell Adhesion Molecule L1/genetics
- Neural Cell Adhesion Molecule L1/metabolism
- Neural Cell Adhesion Molecules/genetics
- Neural Cell Adhesion Molecules/metabolism
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Phenotype
- Photoreceptor Cells, Invertebrate/cytology
- Photoreceptor Cells, Invertebrate/embryology
- Photoreceptor Cells, Invertebrate/metabolism
- Transgenes/genetics
- Wings, Animal/cytology
- Wings, Animal/embryology
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Affiliation(s)
- Lars V Kristiansen
- Instituto de Neurociencias CSIC-UMH, Universidad Miguel Hernandez, Sant Joan d'Alacant, 03550 Spain
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Malhotra JD, Thyagarajan V, Chen C, Isom LL. Tyrosine-phosphorylated and Nonphosphorylated Sodium Channel β1 Subunits Are Differentially Localized in Cardiac Myocytes. J Biol Chem 2004; 279:40748-54. [PMID: 15272007 DOI: 10.1074/jbc.m407243200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Voltage-gated sodium channel alpha and beta subunits expressed in mammalian heart are differentially localized to t-tubules and intercalated disks. Sodium channel beta subunits are multifunctional molecules that participate in channel modulation and cell adhesion. Reversible, receptor-mediated changes in beta1 tyrosine phosphorylation modulate its ability to recruit and associate with ankyrin. The purpose of the present study was to test our hypothesis that tyrosine-phosphorylated beta1 (pYbeta1) and nonphosphorylated beta1 subunits may be differentially localized in heart and thus interact with different cytoskeletal and signaling proteins. We developed an antibody that specifically recognizes pYbeta1 and investigated the differential subcellular localization of beta1 and pYbeta1 in mouse ventricular myocytes. We found that pYbeta1 colocalized with connexin-43, N-cadherin, and Nav1.5 at intercalated disks but was not detected at the t-tubules. Anti-pYbeta1 immunoprecipitates N-cadherin from heart membranes and from cells transfected with beta1 and N-cadherin in the absence of other sodium channel subunits. pYbeta1 does not associate with ankyrinB in heart membranes. N-cadherin and connexin-43 associate with Nav1.5 in heart membranes as assessed by co-immunoprecipitation assays. We propose that sodium channel complexes at intercalated disks of ventricular myocytes are composed of Nav1.5 and pYbeta1 and that these complexes are in close association with both N-cadherin and connexin-43. beta1 phosphorylation appears to regulate its localization to differential subcellular domains.
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Affiliation(s)
- Jyoti D Malhotra
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109-0632, USA
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