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Samata B, Doi D, Nishimura K, Kikuchi T, Watanabe A, Sakamoto Y, Kakuta J, Ono Y, Takahashi J. Purification of functional human ES and iPSC-derived midbrain dopaminergic progenitors using LRTM1. Nat Commun 2016; 7:13097. [PMID: 27739432 PMCID: PMC5067526 DOI: 10.1038/ncomms13097] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 09/02/2016] [Indexed: 12/11/2022] Open
Abstract
Human induced pluripotent stem cells (iPSCs) can provide a promising source of midbrain dopaminergic (mDA) neurons for cell replacement therapy for Parkinson's disease (PD). However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. To eliminate these unwanted cells, cell sorting using antibodies for specific markers such as CORIN or ALCAM has been developed, but neither marker is specific for ventral midbrain. Here we employ a double selection strategy for cells expressing both CORIN and LMX1A::GFP, and report a cell surface marker to enrich mDA progenitors, LRTM1. When transplanted into 6-OHDA-lesioned rats, human iPSC-derived LRTM1+ cells survive and differentiate into mDA neurons in vivo, resulting in a significant improvement in motor behaviour without tumour formation. In addition, there was marked survival of mDA neurons following transplantation of LRTM1+ cells into the brain of an MPTP-treated monkey. Thus, LRTM1 may provide a tool for efficient and safe cell therapy for PD patients.
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Affiliation(s)
- Bumpei Samata
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Daisuke Doi
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Kaneyasu Nishimura
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Tetsuhiro Kikuchi
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Akira Watanabe
- Department of Life Science Frontiers, Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan
| | - Yoshimasa Sakamoto
- Group for Antibody Engineering, KAN Research Institute Inc, Kobe 650-0047, Japan
| | - Jungo Kakuta
- Group for Seed Biologics, KAN Research Institute Inc., Kobe 650-0047, Japan
| | - Yuichi Ono
- Group for Neuronal Differentiation and Development, KAN Research Institute Inc., Kobe 650-0047, Japan.,Group for Regenerative Medicine, KAN Research Institute Inc., Kobe 650-0047, Japan
| | - Jun Takahashi
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.,Department of Neurosurgery, Kyoto University School of Medicine, Kyoto 606-8507, Japan
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52
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Abstract
Repeats are ubiquitous elements of proteins and they play important roles for cellular function and during evolution. Repeats are, however, also notoriously difficult to capture computationally and large scale studies so far had difficulties in linking genetic causes, structural properties and evolutionary trajectories of protein repeats. Here we apply recently developed methods for repeat detection and analysis to a large dataset comprising over hundred metazoan genomes. We find that repeats in larger protein families experience generally very few insertions or deletions (indels) of repeat units but there is also a significant fraction of noteworthy volatile outliers with very high indel rates. Analysis of structural data indicates that repeats with an open structure and independently folding units are more volatile and more likely to be intrinsically disordered. Such disordered repeats are also significantly enriched in sites with a high functional potential such as linear motifs. Furthermore, the most volatile repeats have a high sequence similarity between their units. Since many volatile repeats also show signs of recombination, we conclude they are often shaped by concerted evolution. Intriguingly, many of these conserved yet volatile repeats are involved in host-pathogen interactions where they might foster fast but subtle adaptation in biological arms races. KEY WORDS: protein evolution, domain rearrangements, protein repeats, concerted evolution.
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Affiliation(s)
- Andreas Schüler
- Institute for Evolution and Biodiversity, Westfalian Wilhelms University, Huefferstrasse 1, Muenster, Germany
| | - Erich Bornberg-Bauer
- Institute for Evolution and Biodiversity, Westfalian Wilhelms University, Huefferstrasse 1, Muenster, Germany
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53
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Epigenomic and metabolic responses of hypothalamic POMC neurons to gestational nicotine exposure in adult offspring. Genome Med 2016; 8:93. [PMID: 27609221 PMCID: PMC5015242 DOI: 10.1186/s13073-016-0348-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/23/2016] [Indexed: 01/06/2023] Open
Abstract
Background Epidemiological and animal studies have reported that prenatal nicotine exposure (PNE) leads to obesity and type-2 diabetes in offspring. Central leptin-melanocortin signaling via hypothalamic arcuate proopiomelanocortin (POMC) neurons is crucial for the regulation of energy and glucose balance. Furthermore, hypothalamic POMC neurons were recently found to mediate the anorectic effects of nicotine through activation of acetylcholine receptors. Here, we hypothesized that PNE impairs leptin-melanocortinergic regulation of energy balance in first-generation offspring by altering expression of long non-coding RNAs (lncRNAs) putatively regulating development and/or function of hypothalamic POMC neurons. Methods C57BL/6J females were exposed ad libitum to nicotine through drinking water and crossed with C57BL/6J males. Nicotine exposure was sustained during pregnancy and discontinued at parturition. Offspring development was monitored from birth into adulthood. From the age of 8 weeks, central leptin-melanocortin signaling, diabetes, and obesity susceptibility were assessed in male offspring fed a low-fat or high-fat diet for 16 weeks. Nicotine-exposed and non-exposed C57BL/6J females were also crossed with C57BL/6J males expressing the enhanced green fluorescent protein specifically in POMC neurons. Transgenic male offspring were subjected to laser microdissections and RNA sequencing (RNA-seq) analysis of POMC neurons for determination of nicotine-induced gene expression changes and regulatory lncRNA/protein-coding gene interactions. Results Contrary to expectation based on previous studies, PNE did not impair but rather enhanced leptin-melanocortinergic regulation of energy and glucose balance via POMC neurons in offspring. RNA-seq of laser microdissected POMC neurons revealed only one consistent change, upregulation of Gm15851, a lncRNA of yet unidentified function, in nicotine-exposed offspring. RNA-seq further suggested 82 cis-regulatory lncRNA/protein-coding gene interactions, 19 of which involved coding genes regulating neural development and/or function, and revealed expression of several previously unidentified metabolic, neuroendocrine, and neurodevelopment pathways in POMC neurons. Conclusions PNE does not result in obesity and type 2 diabetes but instead enhances leptin-melanocortinergic feeding and body weight regulation via POMC neurons in adult offspring. PNE leads to selective upregulation of Gm15851, a lncRNA, in adult offspring POMC neurons. POMC neurons express several lncRNAs and pathways possibly regulating POMC neuronal development and/or function. Electronic supplementary material The online version of this article (doi:10.1186/s13073-016-0348-2) contains supplementary material, which is available to authorized users.
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54
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Ledda F, Paratcha G. Assembly of Neuronal Connectivity by Neurotrophic Factors and Leucine-Rich Repeat Proteins. Front Cell Neurosci 2016; 10:199. [PMID: 27555809 PMCID: PMC4977320 DOI: 10.3389/fncel.2016.00199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/29/2016] [Indexed: 11/13/2022] Open
Abstract
Proper function of the nervous system critically relies on sophisticated neuronal networks interconnected in a highly specific pattern. The architecture of these connections arises from sequential developmental steps such as axonal growth and guidance, dendrite development, target determination, synapse formation and plasticity. Leucine-rich repeat (LRR) transmembrane proteins have been involved in cell-type specific signaling pathways that underlie these developmental processes. The members of this superfamily of proteins execute their functions acting as trans-synaptic cell adhesion molecules involved in target specificity and synapse formation or working in cis as cell-intrinsic modulators of neurotrophic factor receptor trafficking and signaling. In this review, we will focus on novel physiological mechanisms through which LRR proteins regulate neurotrophic factor receptor signaling, highlighting the importance of these modulatory events for proper axonal extension and guidance, tissue innervation and dendrite morphogenesis. Additionally, we discuss few examples linking this set of LRR proteins to neurodevelopmental and psychiatric disorders.
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Affiliation(s)
- Fernanda Ledda
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine-University of Buenos Aires (UBA) Buenos Aires, Argentina
| | - Gustavo Paratcha
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET, School of Medicine-University of Buenos Aires (UBA) Buenos Aires, Argentina
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55
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SALM4 suppresses excitatory synapse development by cis-inhibiting trans-synaptic SALM3-LAR adhesion. Nat Commun 2016; 7:12328. [PMID: 27480238 PMCID: PMC4974644 DOI: 10.1038/ncomms12328] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 06/23/2016] [Indexed: 12/01/2022] Open
Abstract
Synaptic adhesion molecules regulate various aspects of synapse development, function and plasticity. These functions mainly involve trans-synaptic interactions and positive regulations, whereas cis-interactions and negative regulation are less understood. Here we report that SALM4, a member of the SALM/Lrfn family of synaptic adhesion molecules, suppresses excitatory synapse development through cis inhibition of SALM3, another SALM family protein with synaptogenic activity. Salm4-mutant (Salm4−/−) mice show increased excitatory synapse numbers in the hippocampus. SALM4 cis-interacts with SALM3, inhibits trans-synaptic SALM3 interaction with presynaptic LAR family receptor tyrosine phosphatases and suppresses SALM3-dependent presynaptic differentiation. Importantly, deletion of Salm3 in Salm4−/− mice (Salm3−/−; Salm4−/−) normalizes the increased excitatory synapse number. These results suggest that SALM4 negatively regulates excitatory synapses via cis inhibition of the trans-synaptic SALM3–LAR adhesion. Synaptic adhesion molecules regulate synapse development and function by both cis and trans-interactions. Here, Lie et al. show that postsynaptic SALM4 regulates excitatory synapse numbers by cis inhibition of the SALM3-LAR transynaptic interaction.
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56
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Abstract
Neurons form precise patterns of connections. The cellular recognition mechanisms regulating the selection of synaptic partners are poorly understood. As final mediators of cell-cell interactions, cell surface and secreted molecules (CSMs) are expected to play important roles in this process. To gain insight into how neurons discriminate synaptic partners, we profiled the transcriptomes of 7 closely related neurons forming distinct synaptic connections in discrete layers in the medulla neuropil of the fly visual system. Our sequencing data revealed that each one of these neurons expresses a unique combination of hundreds of CSMs at the onset of synapse formation. We show that 21 paralogs of the defective proboscis extension response (Dpr) family are expressed in a unique cell-type-specific fashion, consistent with the distinct connectivity pattern of each neuron profiled. Expression analysis of their cognate binding partners, the 9 members of the Dpr interacting protein (DIP) family, revealed complementary layer-specific expression in the medulla, suggestive of interactions between neurons expressing Dpr and those expressing DIP in the same layer. Through coexpression analysis and correlation to connectome data, we identify neurons expressing DIP as a subset of the synaptic partners of the neurons expressing Dpr. We propose that Dpr-DIP interactions regulate patterns of connectivity between the neurons expressing them.
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Affiliation(s)
- Marta Morey
- a Department de Genètica , Facultat de Biologia and Institut de Biomedicina de la Universitat de Barcelona (IBUB) , Barcelona Spain
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57
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Tan L, Zhang KX, Pecot MY, Nagarkar-Jaiswal S, Lee PT, Takemura SY, McEwen JM, Nern A, Xu S, Tadros W, Chen Z, Zinn K, Bellen HJ, Morey M, Zipursky SL. Ig Superfamily Ligand and Receptor Pairs Expressed in Synaptic Partners in Drosophila. Cell 2016; 163:1756-69. [PMID: 26687360 DOI: 10.1016/j.cell.2015.11.021] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 09/27/2015] [Accepted: 11/10/2015] [Indexed: 12/30/2022]
Abstract
Information processing relies on precise patterns of synapses between neurons. The cellular recognition mechanisms regulating this specificity are poorly understood. In the medulla of the Drosophila visual system, different neurons form synaptic connections in different layers. Here, we sought to identify candidate cell recognition molecules underlying this specificity. Using RNA sequencing (RNA-seq), we show that neurons with different synaptic specificities express unique combinations of mRNAs encoding hundreds of cell surface and secreted proteins. Using RNA-seq and protein tagging, we demonstrate that 21 paralogs of the Dpr family, a subclass of immunoglobulin (Ig)-domain containing proteins, are expressed in unique combinations in homologous neurons with different layer-specific synaptic connections. Dpr interacting proteins (DIPs), comprising nine paralogs of another subclass of Ig-containing proteins, are expressed in a complementary layer-specific fashion in a subset of synaptic partners. We propose that pairs of Dpr/DIP paralogs contribute to layer-specific patterns of synaptic connectivity.
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Affiliation(s)
- Liming Tan
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kelvin Xi Zhang
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Matthew Y Pecot
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Sonal Nagarkar-Jaiswal
- Department of Molecular and Human Genetics, HHMI, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shin-Ya Takemura
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Jason M McEwen
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Shuwa Xu
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wael Tadros
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Zhenqing Chen
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, HHMI, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Marta Morey
- Departament de Genètica, Facultat de Biologia and Institut de Biomedicina (IBUB) de la Universitat de Barcelona, Barcelona 08028, Spain.
| | - S Lawrence Zipursky
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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58
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Alsina FC, Hita FJ, Fontanet PA, Irala D, Hedman H, Ledda F, Paratcha G. Lrig1 is a cell-intrinsic modulator of hippocampal dendrite complexity and BDNF signaling. EMBO Rep 2016; 17:601-16. [PMID: 26935556 DOI: 10.15252/embr.201541218] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/28/2016] [Indexed: 11/09/2022] Open
Abstract
Even though many extracellular factors have been identified as promoters of general dendritic growth and branching, little is known about the cell-intrinsic modulators that allow neurons to sculpt distinctive patterns of dendrite arborization. Here, we identify Lrig1, a nervous system-enriched LRR protein, as a key physiological regulator of dendrite complexity of hippocampal pyramidal neurons. Lrig1-deficient mice display morphological changes in proximal dendrite arborization and defects in social interaction. Specifically, knockdown of Lrig1 enhances both primary dendrite formation and proximal dendritic branching of hippocampal neurons, two phenotypes that resemble the effect of BDNF on these neurons. In addition, we show that Lrig1 physically interacts with TrkB and attenuates BDNF signaling. Gain and loss of function assays indicate that Lrig1 restricts BDNF-induced dendrite morphology. Together, our findings reveal a novel and essential role of Lrig1 in regulating morphogenic events that shape the hippocampal circuits and establish that the assembly of TrkB with Lrig1 represents a key mechanism for understanding how specific neuronal populations expand the repertoire of responses to BDNF during brain development.
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Affiliation(s)
- Fernando Cruz Alsina
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Francisco Javier Hita
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Paula Aldana Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Dolores Irala
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Håkan Hedman
- Oncology Research Laboratory, Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Fernanda Ledda
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Gustavo Paratcha
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
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59
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Maeda K, Enomoto A, Hara A, Asai N, Kobayashi T, Horinouchi A, Maruyama S, Ishikawa Y, Nishiyama T, Kiyoi H, Kato T, Ando K, Weng L, Mii S, Asai M, Mizutani Y, Watanabe O, Hirooka Y, Goto H, Takahashi M. Identification of Meflin as a Potential Marker for Mesenchymal Stromal Cells. Sci Rep 2016; 6:22288. [PMID: 26924503 PMCID: PMC4770287 DOI: 10.1038/srep22288] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/11/2016] [Indexed: 01/14/2023] Open
Abstract
Bone marrow-derived mesenchymal stromal cells (BM-MSCs) in culture are derived from BM stromal cells or skeletal stem cells. Whereas MSCs have been exploited in clinical medicine, the identification of MSC-specific markers has been limited. Here, we report that a cell surface and secreted protein, Meflin, is expressed in cultured MSCs, fibroblasts and pericytes, but not other types of cells including epithelial, endothelial and smooth muscle cells. In vivo, Meflin is expressed by immature osteoblasts and chondroblasts. In addition, Meflin is found on stromal cells distributed throughout the BM, and on pericytes and perivascular cells in multiple organs. Meflin maintains the undifferentiated state of cultured MSCs and is downregulated upon their differentiation, consistent with the observation that Meflin-deficient mice exhibit increased number of osteoblasts and accelerated bone development. In the bone and BM, Meflin is more highly expressed in primitive stromal cells that express platelet-derived growth factor receptor α and Sca-1 than the Sca-1-negative adipo-osteogenic progenitors, which create a niche for hematopoiesis. Those results are consistent with a decrease in the number of clonogenic colony-forming unit-fibroblasts within the BM of Meflin-deficient mice. These preliminary data suggest that Meflin is a potential marker for cultured MSCs and their source cells in vivo.
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Affiliation(s)
- Keiko Maeda
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.,Department of Gastroenterology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Atsushi Enomoto
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Akitoshi Hara
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Naoya Asai
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takeshi Kobayashi
- Department of Physiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Asuka Horinouchi
- Department of Nephrology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shoichi Maruyama
- Department of Nephrology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yuichi Ishikawa
- Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, , 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takahiro Nishiyama
- Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, , 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hitoshi Kiyoi
- Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, , 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takuya Kato
- Tumour Cell Biology Laboratory, The Francis-Crick Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, United Kingdom
| | - Kenju Ando
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Liang Weng
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shinji Mii
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Masato Asai
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yasuyuki Mizutani
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.,Department of Gastroenterology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Osamu Watanabe
- Department of Gastroenterology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshiki Hirooka
- Department of Gastroenterology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hidemi Goto
- Department of Gastroenterology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Masahide Takahashi
- Department of Pathology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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60
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Identification of repetitive units in protein structures with ReUPred. Amino Acids 2016; 48:1391-400. [PMID: 26898549 DOI: 10.1007/s00726-016-2187-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 01/23/2016] [Indexed: 01/02/2023]
Abstract
Over the last decade, numerous studies have demonstrated the fundamental importance of tandem repeat (TR) proteins in many biological processes. A plethora of new repeat structures have also been solved. The recently published RepeatsDB provides information on TR proteins. However, a detailed structural characterization of repetitive elements is largely missing, as repeat unit annotation is manually curated and currently covers only 3 % of the bona fide TR proteins. Repeat Protein Unit Predictor (ReUPred) is a novel method for the fast automatic prediction of repeat units and repeat classification using an extensive Structure Repeat Unit Library (SRUL) derived from RepeatsDB. ReUPred uses an iterative structural search against the SRUL to find repetitive units. On a test set of solenoid proteins, ReUPred is able to correctly detect 92 % of the proteins. Unlike previous methods, it is also able to correctly classify solenoid repeats in 89 % of cases. It also outperforms two recent state-of-the-art methods for the repeat unit identification problem. The accurate prediction of repeat units increases the number of annotated repeat units by an order of magnitude compared to the sequence-based Pfam classification. ReUPred is implemented in Python for Linux and freely available from the URL: http://protein.bio.unipd.it/reupred/ .
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61
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Jang S, Oh D, Lee Y, Hosy E, Shin H, van Riesen C, Whitcomb D, Warburton JM, Jo J, Kim D, Kim SG, Um SM, Kwon SK, Kim MH, Roh JD, Woo J, Jun H, Lee D, Mah W, Kim H, Kaang BK, Cho K, Rhee JS, Choquet D, Kim E. Synaptic adhesion molecule IgSF11 regulates synaptic transmission and plasticity. Nat Neurosci 2016; 19:84-93. [PMID: 26595655 PMCID: PMC5010778 DOI: 10.1038/nn.4176] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 10/20/2015] [Indexed: 12/11/2022]
Abstract
Synaptic adhesion molecules regulate synapse development and plasticity through mechanisms that include trans-synaptic adhesion and recruitment of diverse synaptic proteins. We found that the immunoglobulin superfamily member 11 (IgSF11), a homophilic adhesion molecule that preferentially expressed in the brain, is a dual-binding partner of the postsynaptic scaffolding protein PSD-95 and AMPA glutamate receptors (AMPARs). IgSF11 required PSD-95 binding for its excitatory synaptic localization. In addition, IgSF11 stabilized synaptic AMPARs, as determined by IgSF11 knockdown-induced suppression of AMPAR-mediated synaptic transmission and increased surface mobility of AMPARs, measured by high-throughput, single-molecule tracking. IgSF11 deletion in mice led to the suppression of AMPAR-mediated synaptic transmission in the dentate gyrus and long-term potentiation in the CA1 region of the hippocampus. IgSF11 did not regulate the functional characteristics of AMPARs, including desensitization, deactivation or recovery. These results suggest that IgSF11 regulates excitatory synaptic transmission and plasticity through its tripartite interactions with PSD-95 and AMPARs.
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Affiliation(s)
- Seil Jang
- Department of Biological Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Daeyoung Oh
- Department of Biomedical Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
- Department of Psychiatry, CHA Bundang Medical Center, CHA
University, Seoul, Korea
| | - Yeunkum Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science
(IBS), Daejeon 305-701, Korea
| | - Eric Hosy
- University of Bordeaux, Interdisciplinary Institute for
Neuroscience, France; CNRS UMR 5297, F-33000 Bordeaux, France
| | - Hyewon Shin
- Department of Biomedical Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Christoph van Riesen
- Department of Molecular Neurobiology, Max Planck Institute of
Experimental Medicine, D-37075 Göttingen, Germany
| | - Daniel Whitcomb
- School of Clinical Sciences, Faculty of Medicine and Dentistry,
University of Bristol, Whitson street, Bristol, UK
- Centre for Synaptic Plasticity, University of Bristol, Whitson
street, Bristol, UK
| | - Julia M. Warburton
- School of Clinical Sciences, Faculty of Medicine and Dentistry,
University of Bristol, Whitson street, Bristol, UK
| | - Jihoon Jo
- School of Clinical Sciences, Faculty of Medicine and Dentistry,
University of Bristol, Whitson street, Bristol, UK
- Department of Biomedical Sciences, Chonnam National University
Medical School, Gwangju, South Korea
| | - Doyoun Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science
(IBS), Daejeon 305-701, Korea
| | - Sun Gyun Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science
(IBS), Daejeon 305-701, Korea
| | - Seung Min Um
- Department of Biological Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Seok-kyu Kwon
- Department of Biological Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Myoung-Hwan Kim
- Department of Physiology, Seoul National University College of
Medicine, Seoul 110-799, Republic of Korea
- Seoul National University Bundang Hospital, Seongnam, Gyeonggi
463-707, Republic of Korea
| | - Junyeop Daniel Roh
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science
(IBS), Daejeon 305-701, Korea
| | - Jooyeon Woo
- Department of Biological Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Heejung Jun
- Brain and Cognitive Sciences, College of Natural Sciences, Seoul
National University, Seoul 151-747, Korea
| | - Dongmin Lee
- Department of Anatomy and Division of Brain Korea 21 Biomedical
Science, College of Medicine, Korea University, 126-1, 5-Ka, Anam-Dong, Seongbuk-Gu,
Seoul 136-705, Korea
| | - Won Mah
- Department of Anatomy and Neurobiology, School of Dentistry,
Kyungpook National University, Daegu 700-412, Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21 Biomedical
Science, College of Medicine, Korea University, 126-1, 5-Ka, Anam-Dong, Seongbuk-Gu,
Seoul 136-705, Korea
| | - Bong-Kiun Kaang
- Brain and Cognitive Sciences, College of Natural Sciences, Seoul
National University, Seoul 151-747, Korea
| | - Kwangwook Cho
- School of Clinical Sciences, Faculty of Medicine and Dentistry,
University of Bristol, Whitson street, Bristol, UK
- Centre for Synaptic Plasticity, University of Bristol, Whitson
street, Bristol, UK
| | - Jeong-Seop Rhee
- Department of Molecular Neurobiology, Max Planck Institute of
Experimental Medicine, D-37075 Göttingen, Germany
| | - Daniel Choquet
- University of Bordeaux, Interdisciplinary Institute for
Neuroscience, France; CNRS UMR 5297, F-33000 Bordeaux, France
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 305-701, Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science
(IBS), Daejeon 305-701, Korea
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de Wit J, Ghosh A. Specification of synaptic connectivity by cell surface interactions. Nat Rev Neurosci 2015; 17:22-35. [PMID: 26656254 DOI: 10.1038/nrn.2015.3] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The molecular diversification of cell surface molecules has long been postulated to impart specific surface identities on neuronal cell types. The existence of unique cell surface identities would allow neurons to distinguish one another and connect with their appropriate target cells. Although progress has been made in identifying cell type-specific surface molecule repertoires and in characterizing their extracellular interactions, determining how this molecular diversity contributes to the precise wiring of neural circuitry has proven challenging. Here, we review the role of the cadherin, neurexin, immunoglobulin and leucine-rich repeat protein superfamilies in the specification of connectivity. The emerging evidence suggests that the concerted actions of these proteins may critically contribute to the assembly of neural circuits.
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Affiliation(s)
- Joris de Wit
- VIB Center for the Biology of Disease and Center for Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Anirvan Ghosh
- Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffman-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
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Taguchi YH. Identification of aberrant gene expression associated with aberrant promoter methylation in primordial germ cells between E13 and E16 rat F3 generation vinclozolin lineage. BMC Bioinformatics 2015; 16 Suppl 18:S16. [PMID: 26677731 PMCID: PMC4682393 DOI: 10.1186/1471-2105-16-s18-s16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background Transgenerational epigenetics (TGE) are currently considered important in disease, but the mechanisms involved are not yet fully understood. TGE abnormalities expected to cause disease are likely to be initiated during development and to be mediated by aberrant gene expression associated with aberrant promoter methylation that is heritable between generations. However, because methylation is removed and then re-established during development, it is not easy to identify promoter methylation abnormalities by comparing normal lineages with those expected to exhibit TGE abnormalities. Methods This study applied the recently proposed principal component analysis (PCA)-based unsupervised feature extraction to previously reported and publically available gene expression/promoter methylation profiles of rat primordial germ cells, between E13 and E16 of the F3 generation vinclozolin lineage that are expected to exhibit TGE abnormalities, to identify multiple genes that exhibited aberrant gene expression/promoter methylation during development. Results The biological feasibility of the identified genes were tested via enrichment analyses of various biological concepts including pathway analysis, gene ontology terms and protein-protein interactions. All validations suggested superiority of the proposed method over three conventional and popular supervised methods that employed t test, limma and significance analysis of microarrays, respectively. The identified genes were globally related to tumors, the prostate, kidney, testis and the immune system and were previously reported to be related to various diseases caused by TGE. Conclusions Among the genes reported by PCA-based unsupervised feature extraction, we propose that chemokine signaling pathways and leucine rich repeat proteins are key factors that initiate transgenerational epigenetic-mediated diseases, because multiple genes included in these two categories were identified in this study.
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Panza P, Sitko AA, Maischein HM, Koch I, Flötenmeyer M, Wright GJ, Mandai K, Mason CA, Söllner C. The LRR receptor Islr2 is required for retinal axon routing at the vertebrate optic chiasm. Neural Dev 2015; 10:23. [PMID: 26492970 PMCID: PMC4618557 DOI: 10.1186/s13064-015-0050-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/01/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the visual system of most binocular vertebrates, the axons of retinal ganglion cells (RGCs) diverge at the diencephalic midline and extend to targets on both ipsi- and contralateral sides of the brain. While a molecular mechanism explaining ipsilateral guidance decisions has been characterized, less is known of how RGC axons cross the midline. RESULTS Here, we took advantage of the zebrafish, in which all RGC axons project contralaterally at the optic chiasm, to characterize Islr2 as an RGC receptor required for complete retinal axon midline crossing. We used a systematic extracellular protein-protein interaction screening assay to identify two Vasorin paralogs, Vasna and Vasnb, as specific Islr2 ligands. Antibodies against Vasna and Vasnb reveal cellular populations surrounding the retinal axon pathway, suggesting the involvement of these proteins in guidance decisions made by axons of the optic nerve. Specifically, Vasnb marks the membranes of a cellular barricade located anteriorly to the optic chiasm, a structure termed the "glial knot" in higher vertebrates. Loss of function mutations in either vasorin paralog, individually or combined, however, do not exhibit an overt retinal axon projection phenotype, suggesting that additional midline factors, acting either independently or redundantly, compensate for their loss. Analysis of Islr2 knockout mice supports a scenario in which Islr2 controls the coherence of RGC axons through the ventral midline and optic tract. CONCLUSIONS Although stereotypic guidance of RGC axons at the vertebrate optic chiasm is controlled by multiple, redundant mechanisms, and despite the differences in ventral diencephalic tissue architecture, we identify a novel role for the LRR receptor Islr2 in ensuring proper axon navigation at the optic chiasm of both zebrafish and mouse.
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Affiliation(s)
- Paolo Panza
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Genetik, Spemannstraße 35, 72076, Tübingen, Germany.
| | - Austen A Sitko
- Department of Neuroscience, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA
| | - Hans-Martin Maischein
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Genetik, Spemannstraße 35, 72076, Tübingen, Germany.,Present address: Max-Planck-Institut für Herz- und Lungenforschung, Abteilung Genetik der Entwicklung, Ludwigstraße 43, 61231, Bad Nauheim, Germany
| | - Iris Koch
- Max-Planck-Institut für Entwicklungsbiologie, Elektronenmikroskopie, Spemannstraße 35, 72076, Tübingen, Germany
| | - Matthias Flötenmeyer
- Max-Planck-Institut für Entwicklungsbiologie, Elektronenmikroskopie, Spemannstraße 35, 72076, Tübingen, Germany
| | - Gavin J Wright
- Wellcome Trust Sanger Institute, Cell Surface Signalling Laboratory, Hinxton, Cambridge, CB10 1HH, UK
| | - Kenji Mandai
- Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Carol A Mason
- Department of Pathology & Cell Biology, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA.,Department of Neuroscience, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA
| | - Christian Söllner
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Genetik, Spemannstraße 35, 72076, Tübingen, Germany
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Cao Y, Sarria I, Fehlhaber KE, Kamasawa N, Orlandi C, James KN, Hazen JL, Gardner MR, Farzan M, Lee A, Baker S, Baldwin K, Sampath AP, Martemyanov KA. Mechanism for Selective Synaptic Wiring of Rod Photoreceptors into the Retinal Circuitry and Its Role in Vision. Neuron 2015; 87:1248-1260. [PMID: 26402607 PMCID: PMC4583715 DOI: 10.1016/j.neuron.2015.09.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/11/2015] [Accepted: 08/31/2015] [Indexed: 01/06/2023]
Abstract
In the retina, rod and cone photoreceptors form distinct connections with different classes of downstream bipolar cells. However, the molecular mechanisms responsible for their selective connectivity are unknown. Here we identify a cell-adhesion protein, ELFN1, to be essential for the formation of synapses between rods and rod ON-bipolar cells in the primary rod pathway. ELFN1 is expressed selectively in rods where it is targeted to the axonal terminals by the synaptic release machinery. At the synapse, ELFN1 binds in trans to mGluR6, the postsynaptic receptor on rod ON-bipolar cells. Elimination of ELFN1 in mice prevents the formation of synaptic contacts involving rods, but not cones, allowing a dissection of the contributions of primary and secondary rod pathways to retinal circuit function and vision. We conclude that ELFN1 is necessary for the selective wiring of rods into the primary rod pathway and is required for high sensitivity of vision.
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Affiliation(s)
- Yan Cao
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Ignacio Sarria
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Katherine E Fehlhaber
- Jules Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, 100 Stein Plaza, Los Angeles, CA 90095, USA
| | - Naomi Kamasawa
- Electron Microscopy Core Facility, Max Planck Florida Institute, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Cesare Orlandi
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Kiely N James
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92121, USA
| | - Jennifer L Hazen
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92121, USA
| | - Matthew R Gardner
- Department of Infectious Disease, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Michael Farzan
- Department of Infectious Disease, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, 51 Newton Road, Iowa City, IA 52242, USA
| | - Sheila Baker
- Department of Biochemistry, University of Iowa, 51 Newton Road, Iowa City, IA 52242, USA
| | - Kristin Baldwin
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92121, USA
| | - Alapakkam P Sampath
- Jules Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles, 100 Stein Plaza, Los Angeles, CA 90095, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Splicing-Dependent Trans-synaptic SALM3-LAR-RPTP Interactions Regulate Excitatory Synapse Development and Locomotion. Cell Rep 2015; 12:1618-30. [PMID: 26321637 PMCID: PMC4578660 DOI: 10.1016/j.celrep.2015.08.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 06/10/2015] [Accepted: 07/31/2015] [Indexed: 12/02/2022] Open
Abstract
Synaptic adhesion molecules regulate diverse aspects of synapse development and plasticity. SALM3 is a PSD-95-interacting synaptic adhesion molecule known to induce presynaptic differentiation in contacting axons, but little is known about its presynaptic receptors and in vivo functions. Here, we identify an interaction between SALM3 and LAR family receptor protein tyrosine phosphatases (LAR-RPTPs) that requires the mini-exon B splice insert in LAR-RPTPs. In addition, SALM3-dependent presynaptic differentiation requires all three types of LAR-RPTPs. SALM3 mutant (Salm3−/−) mice display markedly reduced excitatory synapse number but normal synaptic plasticity in the hippocampal CA1 region. Salm3−/− mice exhibit hypoactivity in both novel and familiar environments but perform normally in learning and memory tests administered. These results suggest that SALM3 regulates excitatory synapse development and locomotion behavior.
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Choi SY, Han K, Cutforth T, Chung W, Park H, Lee D, Kim R, Kim MH, Choi Y, Shen K, Kim E. Mice lacking the synaptic adhesion molecule Neph2/Kirrel3 display moderate hyperactivity and defective novel object preference. Front Cell Neurosci 2015; 9:283. [PMID: 26283919 PMCID: PMC4517382 DOI: 10.3389/fncel.2015.00283] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/10/2015] [Indexed: 11/13/2022] Open
Abstract
Synaptic adhesion molecules regulate diverse aspects of neuronal synapse development, including synapse specificity, formation, and maturation. Neph2, also known as Kirrel3, is an immunoglobulin superfamily adhesion molecule implicated in intellectual disability, neurocognitive delay associated with Jacobsen syndrome, and autism spectrum disorders. We here report mice lacking Neph2 (Neph2(-/-) mice) display moderate hyperactivity in a familiar, but not novel, environment and defective novel object recognition with normal performances in Morris water maze spatial learning and memory, contextual fear conditioning and extinction, and pattern separation tests. These mice also show normal levels of anxiety-like behaviors, social interaction, and repetitive behaviors. At the synapse level, Neph2(-/-) dentate gyrus granule cells exhibit unaltered dendritic spine density and spontaneous excitatory synaptic transmission. These results suggest that Neph2 is important for normal locomotor activity and object recognition memory.
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Affiliation(s)
- Su-Yeon Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Kihoon Han
- Department of Neuroscience and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University Seoul, South Korea
| | - Tyler Cutforth
- Department of Neurology, Columbia University Medical Center New York, NY, USA
| | - Woosuk Chung
- Department of Biomedical Sciences, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Haram Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Dongsoo Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, South Korea
| | - Ryunhee Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Myeong-Heui Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Yeeun Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Kang Shen
- Department of Biology, Stanford University Stanford, CA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology Daejeon, South Korea ; Center for Synaptic Brain Dysfunctions, Institute for Basic Science Daejeon, South Korea
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Wu H, Barik A, Lu Y, Shen C, Bowman A, Li L, Sathyamurthy A, Lin TW, Xiong WC, Mei L. Slit2 as a β-catenin/Ctnnb1-dependent retrograde signal for presynaptic differentiation. eLife 2015; 4. [PMID: 26159615 PMCID: PMC4498096 DOI: 10.7554/elife.07266] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 06/18/2015] [Indexed: 12/12/2022] Open
Abstract
Neuromuscular junction formation requires proper interaction between motoneurons and muscle cells. β-Catenin (Ctnnb1) in muscle is critical for motoneuron differentiation; however, little is known about the relevant retrograde signal. In this paper, we dissected which functions of muscle Ctnnb1 are critical by an in vivo transgenic approach. We show that Ctnnb1 mutant without the transactivation domain was unable to rescue presynaptic deficits of Ctnnb1 mutation, indicating the involvement of transcription regulation. On the other hand, the cell-adhesion function of Ctnnb1 is dispensable. We screened for proteins that may serve as a Ctnnb1-directed retrograde factor and identified Slit2. Transgenic expression of Slit2 specifically in the muscle was able to diminish presynaptic deficits by Ctnnb1 mutation in mice. Slit2 immobilized on beads was able to induce synaptophysin puncta in axons of spinal cord explants. Together, these observations suggest that Slit2 serves as a factor utilized by muscle Ctnnb1 to direct presynaptic differentiation. DOI:http://dx.doi.org/10.7554/eLife.07266.001 Motor nerves are like electrical wires that connect our spinal cord to the muscles in our body. These nerves communicate with muscles across a connection called the neuromuscular junction. To first form a neuromuscular junction, the motor nerves and muscles each produce molecular cues that tell each other to do their part to build a connection. Beta-catenin in the muscle is known to regulate motor nerve development. However, beta-catenin has two different roles: it helps to coordinate whether neighboring cells stick together, and it can regulate which genes are ‘transcribed’ to produce proteins. It was not known which of these roles is necessary for forming neuromuscular junctions. Wu, Barik et al. now investigate this question by creating mice with mutant forms of beta-catenin in their muscles. Some mice had muscle beta-catenin that could not help cells stick together, and others had beta-catenin that could not control gene transcription. Only mutations that affected the ability of beta-catenin to control transcription caused abnormalities in the neuromuscular junction. However, these problems could be fixed by adding either normal beta-catenin or the mutant form that cannot help cells stick together. Wu, Barik et al. then used molecular tools to explore which genes are turned on by beta-catenin. The experiments showed that beta-catenin causes muscle fibers to produce a protein called Slit2—a developmental cue that controls where neurons grow. Furthermore, the neuromuscular junction defects found in mice without beta-catenin in their muscles could be reduced by making the muscle fibers produce more Slit2. However, not all defects in beta-catenin mutant mice are rescued by Slit2. Future research is needed to identify other beta-catenin-controlled signals and to determine whether such a pathway is altered in neuromuscular disorders. DOI:http://dx.doi.org/10.7554/eLife.07266.002
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Affiliation(s)
- Haitao Wu
- Department of Neurobiology, Institute of Basic Medical Sciences, Beijing, China
| | - Arnab Barik
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Yisheng Lu
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Chengyong Shen
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Andrew Bowman
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Lei Li
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Anupama Sathyamurthy
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Thiri W Lin
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Wen-Cheng Xiong
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, United States
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Dabrowski A, Terauchi A, Strong C, Umemori H. Distinct sets of FGF receptors sculpt excitatory and inhibitory synaptogenesis. Development 2015; 142:1818-30. [PMID: 25926357 DOI: 10.1242/dev.115568] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 03/25/2015] [Indexed: 12/13/2022]
Abstract
Neurons in the brain must establish a balanced network of excitatory and inhibitory synapses during development for the brain to function properly. An imbalance between these synapses underlies various neurological and psychiatric disorders. The formation of excitatory and inhibitory synapses requires precise molecular control. In the hippocampus, the structure crucial for learning and memory, fibroblast growth factor 22 (FGF22) and FGF7 specifically promote excitatory or inhibitory synapse formation, respectively. Knockout of either Fgf gene leads to excitatory-inhibitory imbalance in the mouse hippocampus and manifests in an altered susceptibility to epileptic seizures, underscoring the importance of FGF-dependent synapse formation. However, the receptors and signaling mechanisms by which FGF22 and FGF7 induce excitatory and inhibitory synapse differentiation are unknown. Here, we show that distinct sets of overlapping FGF receptors (FGFRs), FGFR2b and FGFR1b, mediate excitatory or inhibitory presynaptic differentiation in response to FGF22 and FGF7. Excitatory presynaptic differentiation is impaired in Fgfr2b and Fgfr1b mutant mice; however, inhibitory presynaptic defects are only found in Fgfr2b mutants. FGFR2b and FGFR1b are required for an excitatory presynaptic response to FGF22, whereas only FGFR2b is required for an inhibitory presynaptic response to FGF7. We further find that FGFRs are required in the presynaptic neuron to respond to FGF22, and that FRS2 and PI3K, but not PLCγ, mediate FGF22-dependent presynaptic differentiation. Our results reveal the specific receptors and signaling pathways that mediate FGF-dependent presynaptic differentiation, and thereby provide a mechanistic understanding of precise excitatory and inhibitory synapse formation in the mammalian brain.
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Affiliation(s)
- Ania Dabrowski
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Akiko Terauchi
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Cameron Strong
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Hisashi Umemori
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
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Kurochkina NA, Iadarola MJ. Helical assemblies: structure determinants. J Theor Biol 2015; 369:80-84. [PMID: 25613414 DOI: 10.1016/j.jtbi.2015.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 11/30/2022]
Abstract
Protein structural motifs such as helical assemblies and α/β barrels combine secondary structure elements with various types of interactions. Helix-helix interfaces of assemblies - Ankyrin, ARM/HEAT, PUM, LRR, and TPR repeats - exhibit unique amino acid composition and patterns of interactions that correlate with curvature of solenoids, surface geometry and mutual orientation of the helical edges. Inner rows of ankyrin, ARM/HEAT, and PUM-HD repeats utilize edges (i-1, i) and (i+1, i+2) for the interaction of the given α-helix with preceding and following helices correspondingly, whereas outer rows of these proteins and LRR repeats invert this pattern and utilize edges (i-1, i) and (i-3, i-2). Arrangement of contacts observed in protein ligands that bind helical assemblies has to mimic the assembly pattern to provide the same curvature as a determinant of binding specificity. These characteristics are important for understanding fold recognition, specificity of protein-protein interactions, and design of new drugs and materials.
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Affiliation(s)
- Natalya A Kurochkina
- The School of Theoretical Modeling, 1629 K St NW s 300, Washington, DC 20006, United States.
| | - Michael J Iadarola
- Anesthesia Section, Department of Perioperative Medicine, Clinical Center, NIH, Building 10, Room 2C401, 10 Center Drive, MSC 1510, Bethesda, MD 20892, United States.
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Fagotto F. Regulation of Cell Adhesion and Cell Sorting at Embryonic Boundaries. Curr Top Dev Biol 2015; 112:19-64. [DOI: 10.1016/bs.ctdb.2014.11.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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72
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A positional Toll receptor code directs convergent extension in Drosophila. Nature 2014; 515:523-7. [PMID: 25363762 DOI: 10.1038/nature13953] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Elongation of the head-to-tail body axis by convergent extension is a conserved developmental process throughout metazoans. In Drosophila, patterns of transcription factor expression provide spatial cues that induce systematically oriented cell movements and promote tissue elongation. However, the mechanisms by which patterned transcriptional inputs control cell polarity and behaviour have long been elusive. We demonstrate that three Toll family receptors, Toll-2, Toll-6 and Toll-8, are expressed in overlapping transverse stripes along the anterior-posterior axis and act in combination to direct planar polarity and polarized cell rearrangements during convergent extension. Simultaneous disruption of all three receptors strongly reduces actomyosin-driven junctional remodelling and axis elongation, and an ectopic stripe of Toll receptor expression is sufficient to induce planar polarized actomyosin contractility. These results demonstrate that tissue-level patterns of Toll receptor expression provide spatial signals that link positional information from the anterior-posterior patterning system to the essential cell behaviours that drive convergent extension.
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Duan Y, Wang SH, Song J, Mironova Y, Ming GL, Kolodkin AL, Giger RJ. Semaphorin 5A inhibits synaptogenesis in early postnatal- and adult-born hippocampal dentate granule cells. eLife 2014; 3. [PMID: 25313870 PMCID: PMC4236683 DOI: 10.7554/elife.04390] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022] Open
Abstract
Human SEMAPHORIN 5A (SEMA5A) is an autism susceptibility gene; however, its function in brain development is unknown. In this study, we show that mouse Sema5A negatively regulates synaptogenesis in early, developmentally born, hippocampal dentate granule cells (GCs). Sema5A is strongly expressed by GCs and regulates dendritic spine density in a cell-autonomous manner. In the adult mouse brain, newly born Sema5A-/- GCs show an increase in dendritic spine density and increased AMPA-type synaptic responses. Sema5A signals through PlexinA2 co-expressed by GCs, and the PlexinA2-RasGAP activity is necessary to suppress spinogenesis. Like Sema5A-/- mutants, PlexinA2-/- mice show an increase in GC glutamatergic synapses, and we show that Sema5A and PlexinA2 genetically interact with respect to GC spine phenotypes. Sema5A-/- mice display deficits in social interaction, a hallmark of autism-spectrum-disorders. These experiments identify novel intra-dendritic Sema5A/PlexinA2 interactions that inhibit excitatory synapse formation in developmentally born and adult-born GCs, and they provide support for SEMA5A contributions to autism-spectrum-disorders.
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Affiliation(s)
- Yuntao Duan
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Shih-Hsiu Wang
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Juan Song
- Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Yevgeniya Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guo-li Ming
- Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Alex L Kolodkin
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
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74
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Abstract
Precise connections established between pre- and postsynaptic partners during development are essential for the proper function of the nervous system. The olfactory system detects a wide variety of odorants and processes the information in a precisely connected neural circuit. A common feature of the olfactory systems from insects to mammals is that the olfactory receptor neurons (ORNs) expressing the same odorant receptor make one-to-one connections with a single class of second-order olfactory projection neurons (PNs). This represents one of the most striking examples of targeting specificity in developmental neurobiology. Recent studies have uncovered central roles of transmembrane and secreted proteins in organizing this one-to-one connection specificity in the olfactory system. Here, we review recent advances in the understanding of how this wiring specificity is genetically controlled and focus on the mechanisms by which transmembrane and secreted proteins regulate different stages of the Drosophila olfactory circuit assembly in a coordinated manner. We also discuss how combinatorial coding, redundancy, and error-correcting ability could contribute to constructing a complex neural circuit in general.
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75
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de Wit J, Ghosh A. Control of neural circuit formation by leucine-rich repeat proteins. Trends Neurosci 2014; 37:539-50. [PMID: 25131359 DOI: 10.1016/j.tins.2014.07.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/02/2014] [Accepted: 07/24/2014] [Indexed: 01/19/2023]
Abstract
The function of neural circuits depends on the precise connectivity between populations of neurons. Increasing evidence indicates that disruptions in excitatory or inhibitory synapse formation or function lead to excitation/inhibition (E/I) imbalances and contribute to neurodevelopmental and psychiatric disorders. Leucine-rich repeat (LRR)-containing surface proteins have emerged as key organizers of excitatory and inhibitory synapses. Distinct LRR proteins are expressed in different cell types and interact with key pre- and postsynaptic proteins. These protein interaction networks allow LRR proteins to coordinate pre- and postsynaptic elements during synapse formation and differentiation, pathway-specific synapse development, and synaptic plasticity. LRR proteins, therefore, play a critical role in organizing synaptic connections into functional neural circuits, and their dysfunction may contribute to neuropsychiatric disorders.
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Affiliation(s)
- Joris de Wit
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium; KU Leuven, Center for Human Genetics, 3000 Leuven, Belgium.
| | - Anirvan Ghosh
- Neuroscience Discovery, F. Hoffman-La Roche, 4070 Basel, Switzerland
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76
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Zhao X, Kuja-Panula J, Sundvik M, Chen YC, Aho V, Peltola MA, Porkka-Heiskanen T, Panula P, Rauvala H. Amigo adhesion protein regulates development of neural circuits in zebrafish brain. J Biol Chem 2014; 289:19958-75. [PMID: 24904058 DOI: 10.1074/jbc.m113.545582] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Amigo protein family consists of three transmembrane proteins characterized by six leucine-rich repeat domains and one immunoglobulin-like domain in their extracellular moieties. Previous in vitro studies have suggested a role as homophilic adhesion molecules in brain neurons, but the in vivo functions remain unknown. Here we have cloned all three zebrafish amigos and show that amigo1 is the predominant family member expressed during nervous system development in zebrafish. Knockdown of amigo1 expression using morpholino oligonucleotides impairs the formation of fasciculated tracts in early fiber scaffolds of brain. A similar defect in fiber tract development is caused by mRNA-mediated expression of the Amigo1 ectodomain that inhibits adhesion mediated by the full-length protein. Analysis of differentiated neural circuits reveals defects in the catecholaminergic system. At the behavioral level, the disturbed formation of neural circuitry is reflected in enhanced locomotor activity and in the inability of the larvae to perform normal escape responses. We suggest that Amigo1 is essential for the development of neural circuits of zebrafish, where its mechanism involves homophilic interactions within the developing fiber tracts and regulation of the Kv2.1 potassium channel to form functional neural circuitry that controls locomotion.
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Affiliation(s)
| | | | - Maria Sundvik
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
| | - Yu-Chia Chen
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
| | - Vilma Aho
- Institute of Biomedicine/Physiology, University of Helsinki, Helsinki FIN-00014, Finland
| | | | - Tarja Porkka-Heiskanen
- Institute of Biomedicine/Physiology, University of Helsinki, Helsinki FIN-00014, Finland
| | - Pertti Panula
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
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77
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Glerup S, Olsen D, Vaegter CB, Gustafsen C, Sjoegaard SS, Hermey G, Kjolby M, Molgaard S, Ulrichsen M, Boggild S, Skeldal S, Fjorback AN, Nyengaard JR, Jacobsen J, Bender D, Bjarkam CR, Sørensen ES, Füchtbauer EM, Eichele G, Madsen P, Willnow TE, Petersen CM, Nykjaer A. SorCS2 regulates dopaminergic wiring and is processed into an apoptotic two-chain receptor in peripheral glia. Neuron 2014; 82:1074-87. [PMID: 24908487 DOI: 10.1016/j.neuron.2014.04.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2014] [Indexed: 01/12/2023]
Abstract
Balancing trophic and apoptotic cues is critical for development and regeneration of neuronal circuits. Here we identify SorCS2 as a proneurotrophin (proNT) receptor, mediating both trophic and apoptotic signals in conjunction with p75(NTR). CNS neurons, but not glia, express SorCS2 as a single-chain protein that is essential for proBDNF-induced growth cone collapse in developing dopaminergic processes. SorCS2- or p75(NTR)-deficient in mice caused reduced dopamine levels and metabolism and dopaminergic hyperinnervation of the frontal cortex. Accordingly, both knockout models displayed a paradoxical behavioral response to amphetamine reminiscent of ADHD. Contrary, in PNS glia, but not in neurons, proteolytic processing produced a two-chain SorCS2 isoform that mediated proNT-dependent Schwann cell apoptosis. Sciatic nerve injury triggered generation of two-chain SorCS2 in p75(NTR)-positive dying Schwann cells, with apoptosis being profoundly attenuated in Sorcs2(-/-) mice. In conclusion, we have demonstrated that two-chain processing of SorCS2 enables neurons and glia to respond differently to proneurotrophins.
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Affiliation(s)
- Simon Glerup
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
| | - Ditte Olsen
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Christian B Vaegter
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Camilla Gustafsen
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Susanne S Sjoegaard
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Guido Hermey
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Mads Kjolby
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Simon Molgaard
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; MIND Center, Stereology and Electron Microscopy Laboratory, Aarhus University, 8000 C Aarhus, Denmark
| | - Maj Ulrichsen
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Simon Boggild
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Sune Skeldal
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Anja N Fjorback
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Jens R Nyengaard
- MIND Center, Stereology and Electron Microscopy Laboratory, Aarhus University, 8000 C Aarhus, Denmark
| | - Jan Jacobsen
- PET Center, Aarhus University Hospital, 8000 C Aarhus, Denmark
| | - Dirk Bender
- PET Center, Aarhus University Hospital, 8000 C Aarhus, Denmark
| | - Carsten R Bjarkam
- Department of Neurosurgery, Aarhus University Hospital, 8000 C Aarhus, Denmark
| | - Esben S Sørensen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | | | - Gregor Eichele
- Department of Genes and Behaviour, Max Plack Institute, 37077 Göttingen, Germany
| | - Peder Madsen
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Thomas E Willnow
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Claus M Petersen
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark
| | - Anders Nykjaer
- The Lundbeck Foundation Research Center MIND, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Danish Research Institute of Translational Neuroscience DANDRITE Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 C Aarhus, Denmark; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
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78
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Genetic evidence for the adhesion protein IgSF9/Dasm1 to regulate inhibitory synapse development independent of its intracellular domain. J Neurosci 2014; 34:4187-99. [PMID: 24647940 DOI: 10.1523/jneurosci.3671-13.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Normal brain function requires balanced development of excitatory and inhibitory synapses. An imbalance in synaptic transmission underlies many brain disorders such as epilepsy, schizophrenia, and autism. Compared with excitatory synapses, relatively little is known about the molecular control of inhibitory synapse development. We used a genetic approach in mice to identify the Ig superfamily member IgSF9/Dasm1 as a candidate homophilic synaptic adhesion protein that regulates inhibitory synapse development. IgSF9 is expressed in pyramidal cells and subsets of interneurons in the CA1 region of hippocampus. Electrophysiological recordings of acute hippocampal slices revealed that genetic inactivation of the IgSF9 gene resulted in fewer functional inhibitory synapses; however, the strength of the remaining synapses was unaltered. These physiological abnormalities were correlated with decreased expression of inhibitory synapse markers in IgSF9(-/-) mice, providing anatomical evidence for a reduction in inhibitory synapse numbers, whereas excitatory synapse development was normal. Surprisingly, knock-in mice expressing a mutant isoform of IgSF9 lacking the entire cytoplasmic domain (IgSF9(ΔC/ΔC) mice) had no defects in inhibitory synapse development, providing genetic evidence that IgSF9 regulates synapse development via ectodomain interactions rather than acting itself as a signaling receptor. Further, we found that IgSF9 mediated homotypic binding and cell aggregation, but failed to induce synapse formation, suggesting that IgSF9 acts as a cell adhesion molecule (CAM) to maintain synapses. Juvenile IgSF9(-/-) mice exhibited increased seizure susceptibility indicative of an imbalance in synaptic excitation and inhibition. These results provide genetic evidence for a specific role of IgSF9 in inhibitory synapse development/maintenance, presumably by its CAM-like activity.
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79
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Schaper E, Gascuel O, Anisimova M. Deep conservation of human protein tandem repeats within the eukaryotes. Mol Biol Evol 2014; 31:1132-48. [PMID: 24497029 PMCID: PMC3995336 DOI: 10.1093/molbev/msu062] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Tandem repeats (TRs) are a major element of protein sequences in all domains of life. They are particularly abundant in mammals, where by conservative estimates one in three proteins contain a TR. High generation-scale duplication and deletion rates were reported for nucleic TR units. However, it is not known whether protein TR units can also be frequently lost or gained providing a source of variation for rapid adaptation of protein function, or alternatively, tend to have conserved TR unit configurations over long evolutionary times. To obtain a systematic picture, we performed a proteome-wide analysis of the mode of evolution for human protein TRs. For this purpose, we propose a novel method for the detection of orthologous TRs based on circular profile hidden Markov models. For all detected TRs, we reconstructed bispecies TR unit phylogenies across 61 eukaryotes ranging from human to yeast. Moreover, we performed additional analyses to correlate functional and structural annotations of human TRs with their mode of evolution. Surprisingly, we find that the vast majority of human TRs are ancient, with TR unit number and order preserved intact since distant speciation events. For example, ≥61% of all human TRs have been strongly conserved at least since the root of all mammals, approximately 300 Ma. Further, we find no human protein TR that shows evidence for strong recent duplications and deletions. The results are in contrast to the high generation-scale mutability of nucleic TRs. Presumably, most protein TRs fold into stable and conserved structures that are indispensable for the function of the TR-containing protein. All of our data and results are available for download from http://www.atgc-montpellier.fr/TRE.
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Affiliation(s)
- Elke Schaper
- Department of Computer Science, ETH Zürich, Zürich, Switzerland
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80
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Autoantibodies to epilepsy-related LGI1 in limbic encephalitis neutralize LGI1-ADAM22 interaction and reduce synaptic AMPA receptors. J Neurosci 2014; 33:18161-74. [PMID: 24227725 DOI: 10.1523/jneurosci.3506-13.2013] [Citation(s) in RCA: 228] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
More than 30 mutations in LGI1, a secreted neuronal protein, have been reported with autosomal dominant lateral temporal lobe epilepsy (ADLTE). Although LGI1 haploinsufficiency is thought to cause ADLTE, the underlying molecular mechanism that results in abnormal brain excitability remains mysterious. Here, we focused on a mode of action of LGI1 autoantibodies associated with limbic encephalitis (LE), which is one of acquired epileptic disorders characterized by subacute onset of amnesia and seizures. We comprehensively screened human sera from patients with immune-mediated neurological disorders for LGI1 autoantibodies, which also uncovered novel autoantibodies against six cell surface antigens including DCC, DPP10, and ADAM23. Our developed ELISA arrays revealed a specific role for LGI1 antibodies in LE and concomitant involvement of multiple antibodies, including LGI1 antibodies in neuromyotonia, a peripheral nerve disorder. LGI1 antibodies associated with LE specifically inhibited the ligand-receptor interaction between LGI1 and ADAM22/23 by targeting the EPTP repeat domain of LGI1 and reversibly reduced synaptic AMPA receptor clusters in rat hippocampal neurons. Furthermore, we found that disruption of LGI1-ADAM22 interaction by soluble extracellular domain of ADAM22 was sufficient to reduce synaptic AMPA receptors in rat hippocampal neurons and that levels of AMPA receptor were greatly reduced in the hippocampal dentate gyrus in the epileptic LGI1 knock-out mouse. Therefore, either genetic or acquired loss of the LGI1-ADAM22 interaction reduces the AMPA receptor function, causing epileptic disorders. These results suggest that by finely regulating the synaptic AMPA receptors, the LGI1-ADAM22 interaction maintains physiological brain excitability throughout life.
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81
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Di Domenico T, Potenza E, Walsh I, Parra RG, Giollo M, Minervini G, Piovesan D, Ihsan A, Ferrari C, Kajava AV, Tosatto SCE. RepeatsDB: a database of tandem repeat protein structures. Nucleic Acids Res 2013; 42:D352-7. [PMID: 24311564 PMCID: PMC3964956 DOI: 10.1093/nar/gkt1175] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
RepeatsDB (http://repeatsdb.bio.unipd.it/) is a database of annotated tandem repeat protein structures. Tandem repeats pose a difficult problem for the analysis of protein structures, as the underlying sequence can be highly degenerate. Several repeat types haven been studied over the years, but their annotation was done in a case-by-case basis, thus making large-scale analysis difficult. We developed RepeatsDB to fill this gap. Using state-of-the-art repeat detection methods and manual curation, we systematically annotated the Protein Data Bank, predicting 10 745 repeat structures. In all, 2797 structures were classified according to a recently proposed classification schema, which was expanded to accommodate new findings. In addition, detailed annotations were performed in a subset of 321 proteins. These annotations feature information on start and end positions for the repeat regions and units. RepeatsDB is an ongoing effort to systematically classify and annotate structural protein repeats in a consistent way. It provides users with the possibility to access and download high-quality datasets either interactively or programmatically through web services.
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Affiliation(s)
- Tomás Di Domenico
- Department of Biomedical Sciences, University of Padua, 35131 Padova, Italy, Department of Biological Chemistry, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina, Department of Information Engineering, University of Padua, 35121 Padova, Italy, Department of Biosciences, COMSATS Institute of Information Technology, Sahiwal, Pakistan, Centre de Recherches de Biochimie Macromoléculaire, CNRS, 34293 Montpellier Cedex 5, France and Institut de Biologie Computationnelle, 34293 Montpellier Cedex 5, France
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82
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Dolan J, Mitchell KJ. Mutation of Elfn1 in mice causes seizures and hyperactivity. PLoS One 2013; 8:e80491. [PMID: 24312227 PMCID: PMC3842350 DOI: 10.1371/journal.pone.0080491] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 10/12/2013] [Indexed: 02/02/2023] Open
Abstract
A growing number of proteins with extracellular leucine-rich repeats (eLRRs) have been implicated in directing neuronal connectivity. We previously identified a novel family of eLRR proteins in mammals: the Elfns are transmembrane proteins with 6 LRRs, a fibronectin type-3 domain and a long cytoplasmic tail. The recent discovery that Elfn1 protein, expressed postsynaptically, can direct the elaboration of specific electrochemical properties of synapses between particular cell types in the hippocampus strongly reinforces this hypothesis. Here, we present analyses of an Elfn1 mutant mouse line and demonstrate a functional requirement for this gene in vivo. We first carried out detailed expression analysis of Elfn1 using a β-galactosidase reporter gene in the knockout line. Elfn1 is expressed in distinct subsets of interneurons of the hippocampus and cortex, and also in discrete subsets of cells in the habenula, septum, globus pallidus, dorsal subiculum, amygdala and several other regions. Elfn1 is expressed in diverse cell types, including local GABAergic interneurons as well as long-range projecting GABAergic and glutamatergic neurons. Elfn1 protein localises to axons of excitatory neurons in the habenula, and long-range GABAergic neurons of the globus pallidus, suggesting the possibility of additional roles for Elfn1 in axons or presynaptically. While gross anatomical analyses did not reveal any obvious neuroanatomical abnormalities, behavioural analyses clearly illustrate functional effects of Elfn1 mutation. Elfn1 mutant mice exhibit seizures, subtle motor abnormalities, reduced thigmotaxis and hyperactivity. The hyperactivity is paradoxically reversible by treatment with the stimulant amphetamine, consistent with phenotypes observed in animals with habenular lesions. These analyses reveal a requirement for Elfn1 in brain function and are suggestive of possible relevance to the etiology and pathophysiology of epilepsy and attention-deficit hyperactivity disorder.
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Affiliation(s)
- Jackie Dolan
- Smurfit Institute of Genetics and Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Kevin J. Mitchell
- Smurfit Institute of Genetics and Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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83
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Soler-Llavina GJ, Arstikaitis P, Morishita W, Ahmad M, Südhof TC, Malenka RC. Leucine-rich repeat transmembrane proteins are essential for maintenance of long-term potentiation. Neuron 2013; 79:439-46. [PMID: 23931994 DOI: 10.1016/j.neuron.2013.06.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2013] [Indexed: 11/18/2022]
Abstract
Leucine-rich repeat transmembrane proteins (LRRTMs) are synaptic cell adhesion molecules that trigger excitatory synapse assembly in cultured neurons and influence synaptic function in vivo, but their role in synaptic plasticity is unknown. shRNA-mediated knockdown (KD) of LRRTM1 and LRRTM2 in vivo in CA1 pyramidal neurons of newborn mice blocked long-term potentiation (LTP) in acute hippocampal slices. Molecular replacement experiments revealed that the LRRTM2 extracellular domain is sufficient for LTP, probably because it mediates binding to neurexins (Nrxs). Examination of surface expression of endogenous AMPA receptors (AMPARs) in cultured neurons suggests that LRRTMs maintain newly delivered AMPARs at synapses after LTP induction. LRRTMs are also required for LTP of mature synapses on adult CA1 pyramidal neurons, indicating that the block of LTP in neonatal synapses by LRRTM1 and LRRTM2 KD is not due to impairment of synapse maturation.
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Affiliation(s)
- Gilberto J Soler-Llavina
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
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84
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Round J, Ross B, Angel M, Shields K, Lom B. Slitrk gene duplication and expression in the developing zebrafish nervous system. Dev Dyn 2013; 243:339-49. [PMID: 24123428 DOI: 10.1002/dvdy.24076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/03/2013] [Accepted: 10/03/2013] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The Slitrk family of leucine-rich repeat (LRR) transmembrane proteins bears structural similarity to the Slits and the Trk receptor families, which exert well-established roles in directing nervous system development. Slitrks are less well understood, although they are highly expressed in the developing vertebrate nervous system. Moreover, slitrk variants are associated with several sensory and neuropsychiatric disorders, including myopia, deafness, obsessive-compulsive disorder (OCD), schizophrenia, and Tourette syndrome. Loss-of-function studies in mice show that Slitrks modulate neurite outgrowth and inhibitory synapse formation, although the molecular mechanisms of Slitrk function remain poorly characterized. RESULTS As a prelude to examining the functional roles of Slitrks, we identified eight slitrk orthologs in zebrafish and observed that seven of the eight orthologs were actively transcribed in the nervous system at embryonic, larval, and adult stages. Similar to previous findings in mice and humans, zebrafish slitrks exhibited unique but overlapping spatial and temporal expression patterns in the developing brain, retina, and spinal cord. CONCLUSIONS Zebrafish express Slitrks in the developing central nervous system at times and locations important to neuronal morphogenesis and synaptogenesis. Future studies will use zebrafish as a convenient, cost-effective model organism to characterize the functional roles of Slitrks in nervous system development.
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Affiliation(s)
- Jennifer Round
- Department of Biology and Program in Neuroscience, Davidson College, Davidson, North Carolina
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85
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Baggio F, Bozzato A, Benna C, Leonardi E, Romoli O, Cognolato M, Tosatto SCE, Costa R, Sandrelli F. 2mit, an intronic gene of Drosophila melanogaster timeless2, is involved in behavioral plasticity. PLoS One 2013; 8:e76351. [PMID: 24098788 PMCID: PMC3786989 DOI: 10.1371/journal.pone.0076351] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 08/27/2013] [Indexed: 12/15/2022] Open
Abstract
Background Intronic genes represent ~6% of the total gene complement in Drosophila melanogaster and ~85% of them encode for proteins. We recently characterized the D. melanogastertimeless2 (tim2) gene, showing its active involvement in chromosomal stability and light synchronization of the adult circadian clock. The protein coding gene named 2mit maps on the 11thtim2 intron in the opposite transcriptional orientation. Methodology/Principal Findings Here we report the molecular and functional characterization of 2mit. The 2mit gene is expressed throughout Drosophila development, localizing mainly in the nervous system during embryogenesis and mostly in the mushroom bodies and ellipsoid body of the central complex in the adult brain. Insilico analyses revealed that 2mit encodes a putative leucine-Rich Repeat transmembrane receptor with intrinsically disordered regions, harboring several fully conserved functional interaction motifs in the cytosolic side. Using insertional mutations, tissue-specific over-expression, and down-regulation approaches, it was found that 2mit is implicated in adult short-term memory, assessed by a courtship conditioning assay. In D. melanogaster, tim2 and 2mit do not seem to be functionally related. Bioinformatic analyses identified 2MIT orthologs in 21 Drosophilidae, 4 Lepidoptera and in Apis mellifera. In addition, the tim2-2mit host-nested gene organization was shown to be present in A. mellifera and maintained among Drosophila species. Within the Drosophilidae 2mit-hosting tim2 intron, insilico approaches detected a neuronal specific transcriptional binding site which might have contributed to preserve the specific host-nested gene association across Drosophila species. Conclusions/Significance Taken together, these results indicate that 2mit, a gene mainly expressed in the nervous system, has a role in the behavioral plasticity of the adult Drosophila. The presence of a putative 2mit regulatory enhancer within the 2mit-hosting tim2 intron could be considered an evolutionary constraint potentially involved in maintaining the tim2-2mit host-nested chromosomal architecture during the evolution of Drosophila species.
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Affiliation(s)
- Francesca Baggio
- Dipartimento di Biologia, Università degli Studi di Padova Padova, Italy
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86
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NGL-2 regulates pathway-specific neurite growth and lamination, synapse formation, and signal transmission in the retina. J Neurosci 2013; 33:11949-59. [PMID: 23864682 DOI: 10.1523/jneurosci.1521-13.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Parallel processing is an organizing principle of many neural circuits. In the retina, parallel neuronal pathways process signals from rod and cone photoreceptors and support vision over a wide range of light levels. Toward this end, rods and cones form triad synapses with dendrites of distinct bipolar cell types, and the axons or dendrites, respectively, of horizontal cells (HCs). The molecular cues that promote the formation of specific neuronal pathways remain largely unknown. Here, we discover that developing and mature HCs express the leucine-rich repeat (LRR)-containing protein netrin-G ligand 2 (NGL-2). NGL-2 localizes selectively to the tips of HC axons, which form reciprocal connections with rods. In mice with null mutations in Ngl-2 (Ngl-2⁻/⁻), many branches of HC axons fail to stratify in the outer plexiform layer (OPL) and invade the outer nuclear layer. In addition, HC axons expand lateral territories and increase coverage of the OPL, but establish fewer synapses with rods. NGL-2 can form transsynaptic adhesion complexes with netrin-G2, which we show to be expressed by photoreceptors. In Ngl-2⁻/⁻ mice, we find specific defects in the assembly of presynaptic ribbons in rods, indicating that reverse signaling of complexes involving NGL-2 regulates presynaptic maturation. The development of HC dendrites and triad synapses of cone photoreceptors proceeds normally in the absence of NGL-2 and in vivo electrophysiology reveals selective defects in rod-mediated signal transmission in Ngl-2⁻/⁻ mice. Thus, our results identify NGL-2 as a central component of pathway-specific development in the outer retina.
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In vivo analysis of Lrig genes reveals redundant and independent functions in the inner ear. PLoS Genet 2013; 9:e1003824. [PMID: 24086156 PMCID: PMC3784559 DOI: 10.1371/journal.pgen.1003824] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/08/2013] [Indexed: 02/06/2023] Open
Abstract
Lrig proteins are conserved transmembrane proteins that modulate a variety of signaling pathways from worm to humans. In mammals, there are three family members – Lrig1, Lrig2, and Lrig3 – that are defined by closely related extracellular domains with a similar arrangement of leucine rich repeats and immunoglobulin domains. However, the intracellular domains show little homology. Lrig1 inhibits EGF signaling through internalization and degradation of ErbB receptors. Although Lrig3 can also bind ErbB receptors in vitro, it is unclear whether Lrig2 and Lrig3 exhibit similar functions to Lrig1. To gain insights into Lrig gene functions in vivo, we compared the expression and function of the Lrigs in the inner ear, which offers a sensitive system for detecting effects on morphogenesis and function. We find that all three family members are expressed in the inner ear throughout development, with Lrig1 and Lrig3 restricted to subsets of cells and Lrig2 expressed more broadly. Lrig1 and Lrig3 overlap prominently in the developing vestibular apparatus and simultaneous removal of both genes disrupts inner ear morphogenesis. This suggests that these two family members act redundantly in the otic epithelium. In contrast, although Lrig1 and Lrig2 are frequently co-expressed, Lrig1−/−;Lrig2−/− double mutant ears show no enhanced structural abnormalities. At later stages, Lrig1 expression is sustained in non-sensory tissues, whereas Lrig2 levels are enhanced in neurons and sensory epithelia. Consistent with these distinct expression patterns, Lrig1 and Lrig2 mutant mice exhibit different forms of impaired auditory responsiveness. Notably, Lrig1−/−;Lrig2−/− double mutant mice display vestibular deficits and suffer from a more severe auditory defect that is accompanied by a cochlear innervation phenotype not present in single mutants. Thus, Lrig genes appear to act both redundantly and independently, with Lrig2 emerging as the most functionally distinct family member. The mammalian genome encodes three Lrig family members - Lrig1, Lrig2, and Lrig3. Lrig proteins share a characteristic extracellular domain that can bind to a variety of signaling receptors, but the three family members show little homology in the cytoplasmic domain. Lrig1 is a tumor suppressor gene required for normal EGF signaling. Whether Lrig2 and Lrig3 play similar roles is not known. To address this gap in knowledge, we compared the expression and function of Lrigs in the mouse inner ear, which is responsible for hearing and balance. Even subtle changes in the inner ear cause easily detected deficits in hearing and balance, making it an ideal system for analysis of gene function. We find that Lrigs can act both redundantly and independently in the inner ear, with Lrig1 and Lrig3 cooperating to control morphogenesis and Lrig1 and Lrig2 acting independently to ensure proper cochlear function. However, loss of both Lrig1 and Lrig2 causes a more severe auditory response deficit and additionally causes a vestibular defect, suggesting some overlapping activities. Our findings provide new insights into the in vivo functions for the Lrig genes, which play important roles in vertebrate development and disease.
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88
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Li X, Roszko I, Sepich DS, Ni M, Hamm HE, Marlow FL, Solnica-Krezel L. Gpr125 modulates Dishevelled distribution and planar cell polarity signaling. Development 2013; 140:3028-39. [PMID: 23821037 DOI: 10.1242/dev.094839] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During vertebrate gastrulation, Wnt/planar cell polarity (PCP) signaling orchestrates polarized cell behaviors underlying convergence and extension (C&E) movements to narrow embryonic tissues mediolaterally and lengthen them anteroposteriorly. Here, we have identified Gpr125, an adhesion G protein-coupled receptor, as a novel modulator of the Wnt/PCP signaling system. Excess Gpr125 impaired C&E movements and the underlying cell and molecular polarities. Reduced Gpr125 function exacerbated the C&E and facial branchiomotor neuron (FBMN) migration defects of embryos with reduced Wnt/PCP signaling. At the molecular level, Gpr125 recruited Dishevelled to the cell membrane, a prerequisite for Wnt/PCP activation. Moreover, Gpr125 and Dvl mutually clustered one another to form discrete membrane subdomains, and the Gpr125 intracellular domain directly interacted with Dvl in pull-down assays. Intriguingly, Dvl and Gpr125 were able to recruit a subset of PCP components into membrane subdomains, suggesting that Gpr125 may modulate the composition of Wnt/PCP membrane complexes. Our study reveals a role for Gpr125 in PCP-mediated processes and provides mechanistic insight into Wnt/PCP signaling.
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Affiliation(s)
- Xin Li
- Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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89
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Pizzo E, Sarcinelli C, Sheng J, Fusco S, Formiggini F, Netti P, Yu W, D'Alessio G, Hu GF. Ribonuclease/angiogenin inhibitor 1 regulates stress-induced subcellular localization of angiogenin to control growth and survival. J Cell Sci 2013; 126:4308-19. [PMID: 23843625 DOI: 10.1242/jcs.134551] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Angiogenin (ANG) promotes cell growth and survival. Under growth conditions, ANG undergoes nuclear translocation and accumulates in the nucleolus where it stimulates rRNA transcription. When cells are stressed, ANG mediates the production of tRNA-derived stress-induced small RNA (tiRNA), which reprograms protein translation into a survival mechanism. The ribonucleolytic activity of ANG is essential for both processes but how this activity is regulated is unknown. We report here that ribonuclease/angiogenin inhibitor 1 (RNH1) controls both the localization and activity of ANG. Under growth conditions, ANG is located in the nucleus and is not associated with RNH1 so that the ribonucleolytic activity is retained to ensure rRNA transcription. Cytoplasmic ANG is associated with and inhibited by RNH1 so that random cleavage of cellular RNA is prevented. Under stress conditions, ANG is localized to the cytoplasm and is concentrated in stress granules where it is not associated with RNH1 and thus remains enzymatically active for tiRNA production. By contrast, nuclear ANG is associated with RNH1 in stressed cells to ensure that the enzymatic activity is inhibited and no unnecessary rRNA is produced to save anabolic energy. Knockdown of RNH1 abolished stress-induced relocalization of ANG and decreased cell growth and survival.
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Affiliation(s)
- Elio Pizzo
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, via Cintia, Naples 80126, Italy
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90
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Özkan E, Carrillo RA, Eastman CL, Weiszmann R, Waghray D, Johnson KG, Zinn K, Celniker SE, Garcia KC. An extracellular interactome of immunoglobulin and LRR proteins reveals receptor-ligand networks. Cell 2013; 154:228-39. [PMID: 23827685 PMCID: PMC3756661 DOI: 10.1016/j.cell.2013.06.006] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 04/02/2013] [Accepted: 06/05/2013] [Indexed: 10/26/2022]
Abstract
Extracellular domains of cell surface receptors and ligands mediate cell-cell communication, adhesion, and initiation of signaling events, but most existing protein-protein "interactome" data sets lack information for extracellular interactions. We probed interactions between receptor extracellular domains, focusing on a set of 202 proteins composed of the Drosophila melanogaster immunoglobulin superfamily (IgSF), fibronectin type III (FnIII), and leucine-rich repeat (LRR) families, which are known to be important in neuronal and developmental functions. Out of 20,503 candidate protein pairs tested, we observed 106 interactions, 83 of which were previously unknown. We "deorphanized" the 20 member subfamily of defective-in-proboscis-response IgSF proteins, showing that they selectively interact with an 11 member subfamily of previously uncharacterized IgSF proteins. Both subfamilies interact with a single common "orphan" LRR protein. We also observed interactions between Hedgehog and EGFR pathway components. Several of these interactions could be visualized in live-dissected embryos, demonstrating that this approach can identify physiologically relevant receptor-ligand pairs.
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Affiliation(s)
- Engin Özkan
- Department of Molecular and Cellular Physiology, and Structural Biology, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert A. Carrillo
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - Catharine L. Eastman
- Department of Molecular and Cellular Physiology, and Structural Biology, Stanford, CA 94305, USA
| | - Richard Weiszmann
- Department of Genome Dynamics, Berkeley Genome Project, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Deepa Waghray
- Department of Molecular and Cellular Physiology, and Structural Biology, Stanford, CA 94305, USA
| | - Karl G. Johnson
- Department of Biology, and Neuroscience, Pomona College, Claremont, CA 91711, USA
| | - Kai Zinn
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - Susan E. Celniker
- Department of Genome Dynamics, Berkeley Genome Project, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - K. Christopher Garcia
- Department of Molecular and Cellular Physiology, and Structural Biology, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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91
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Gissendanner CR, Kelley TD. The C. elegans gene pan-1 encodes novel transmembrane and cytoplasmic leucine-rich repeat proteins and promotes molting and the larva to adult transition. BMC DEVELOPMENTAL BIOLOGY 2013; 13:21. [PMID: 23682709 PMCID: PMC3679943 DOI: 10.1186/1471-213x-13-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 05/02/2013] [Indexed: 01/06/2023]
Abstract
Background Extracellular leucine-rich repeat (eLRR) proteins are a highly diverse superfamily of membrane-associated or secreted proteins. In the membrane-associated eLRR proteins, the leucine-rich repeat motifs interact with the extracellular matrix and other ligands. Characterizing their functions in animal model systems is key to deciphering their activities in various developmental processes. Results In this study, we identify pan-1 as a critical regulator of C. elegans larval development. pan-1 encodes both transmembrane and cytoplasmic isoforms that vary in the presence and number of leucine-rich repeats. RNAi experiments reveal that pan-1 is required for developmental processes that occur during the mid to late larval stages. Specifically, pan-1 loss of function causes a late larval arrest with a failure to complete development of the gonad, vulva, and hypodermis. pan-1 is also required for early larval ecdysis and execution of the molting cycle at the adult molt. We also provide evidence that pan-1 functionally interacts with the heterochronic gene lin-29 during the molting process. Conclusions We show that PAN-1 is a critical regulator of larval development. Our data suggests that PAN-1 promotes developmental progression of multiple tissues during the transition from a larva to a reproductive adult. We further demonstrate that the activity of PAN-1 is complex with diverse roles in the regulation of animal development.
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Affiliation(s)
- Chris R Gissendanner
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA.
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92
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Mironova YA, Giger RJ. Where no synapses go: gatekeepers of circuit remodeling and synaptic strength. Trends Neurosci 2013; 36:363-73. [PMID: 23642707 DOI: 10.1016/j.tins.2013.04.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 02/07/2023]
Abstract
Growth inhibitory molecules in the adult mammalian central nervous system (CNS) have been implicated in the blocking of axonal sprouting and regeneration following injury. Prominent CNS regeneration inhibitors include Nogo-A, oligodendrocyte myelin glycoprotein (OMgp), and chondroitin sulfate proteoglycans (CSPGs), and a key question concerns their physiological role in the naïve CNS. Emerging evidence suggests novel functions in dendrites and at synapses of glutamatergic neurons. CNS regeneration inhibitors target the neuronal actin cytoskeleton to regulate dendritic spine maturation, long-term synapse stability, and Hebbian forms of synaptic plasticity. This is accomplished in part by antagonizing plasticity-promoting signaling pathways activated by neurotrophic factors. Altered function of CNS regeneration inhibitors is associated with mental illness and loss of long-lasting memory, suggesting unexpected and novel physiological roles for these molecules in brain health.
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, 3065 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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93
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Li P, Collins KM, Koelle MR, Shen K. LIN-12/Notch signaling instructs postsynaptic muscle arm development by regulating UNC-40/DCC and MADD-2 in Caenorhabditis elegans. eLife 2013; 2:e00378. [PMID: 23539368 PMCID: PMC3601818 DOI: 10.7554/elife.00378] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/07/2013] [Indexed: 12/22/2022] Open
Abstract
The diverse cell types and the precise synaptic connectivity between them are the cardinal features of the nervous system. Little is known about how cell fate diversification is linked to synaptic target choices. Here we investigate how presynaptic neurons select one type of muscles, vm2, as a synaptic target and form synapses on its dendritic spine-like muscle arms. We found that the Notch-Delta pathway was required to distinguish target from non-target muscles. APX-1/Delta acts in surrounding cells including the non-target vm1 to activate LIN-12/Notch in the target vm2. LIN-12 functions cell-autonomously to up-regulate the expression of UNC-40/DCC and MADD-2 in vm2, which in turn function together to promote muscle arm formation and guidance. Ectopic expression of UNC-40/DCC in non-target vm1 muscle is sufficient to induce muscle arm extension from these cells. Therefore, the LIN-12/Notch signaling specifies target selection by selectively up-regulating guidance molecules and forming muscle arms in target cells. DOI:http://dx.doi.org/10.7554/eLife.00378.001 The development of the nervous system involves the formation of complex networks of connections between diverse cell types, such as motor neurons, interneurons and pyramidal cells. However, the mechanisms by which individual cells are programmed to acquire particular identities, and how they are instructed to form connections with other specific cells, remain unclear. In many species, the Notch signaling pathway has a role in setting up these networks. Notch is a transmembrane protein, which means that it has one component inside the cell and another outside. When a ligand binds to the extracellular part of Notch, this causes the receptor to break in two. The intracellular domain then travels to the nucleus where it can influence gene expression. The nematode worm (C. elegans), which has two Notch receptors, is often used to study the formation of neuronal networks because each worm has only around 300 neurons, and they are connected in roughly the same way in each worm. C. elegans relies on two types of cell that are very similar to each other—type-1 and type-2 vulval muscle cells—to lay eggs, and the neurons that trigger egg-laying form synaptic connections on specialized structures called muscle arms. However, these structures are found only in type-2 vulval muscle. To investigate the mechanisms underlying the formation of the egg-laying circuit, Li et al. screened large numbers of mutant worms to find animals that lacked muscle arms. They identified a number of such mutants, which laid fewer eggs compared to wild-type worms, and found that they all had mutations in genes that encode for proteins or ligands that are involved in the LIN-12/Notch pathway. This pathway mediates cell–cell interactions that help to specify cell fates. Li et al. showed that type-2 vulval muscle cells develop muscle arms when their neighbors—type-1 vulval muscle cells and vulval epithelial cells—produce enough ligand to activate the LIN-12 Notch receptor on the type-2 vulval muscle cells. They also identified two of the downstream targets of LIN-12, and found that artificially expressing one of these in type-1 vulval muscle cells is sufficient to trigger the formation of muscle arms. The work of Li et al. provides further evidence that the Notch signalling pathway, which is well known for its role in early development, also acts at later developmental stages to determine cell fate and patterns of connectivity. DOI:http://dx.doi.org/10.7554/eLife.00378.002
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Affiliation(s)
- Pengpeng Li
- Department of Biology , Howard Hughes Medical Institute, Stanford University , Stanford , United States
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94
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Yim YS, Kwon Y, Nam J, Yoon HI, Lee K, Kim DG, Kim E, Kim CH, Ko J. Slitrks control excitatory and inhibitory synapse formation with LAR receptor protein tyrosine phosphatases. Proc Natl Acad Sci U S A 2013; 110:4057-62. [PMID: 23345436 PMCID: PMC3593915 DOI: 10.1073/pnas.1209881110] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The balance between excitatory and inhibitory synaptic inputs, which is governed by multiple synapse organizers, controls neural circuit functions and behaviors. Slit- and Trk-like proteins (Slitrks) are a family of synapse organizers, whose emerging synaptic roles are incompletely understood. Here, we report that Slitrks are enriched in postsynaptic densities in rat brains. Overexpression of Slitrks promoted synapse formation, whereas RNAi-mediated knockdown of Slitrks decreased synapse density. Intriguingly, Slitrks were required for both excitatory and inhibitory synapse formation in an isoform-dependent manner. Moreover, Slitrks required distinct members of the leukocyte antigen-related receptor protein tyrosine phosphatase (LAR-RPTP) family to trigger synapse formation. Protein tyrosine phosphatase σ (PTPσ), in particular, was specifically required for excitatory synaptic differentiation by Slitrks, whereas PTPδ was necessary for inhibitory synapse differentiation. Taken together, these data suggest that combinatorial interactions of Slitrks with LAR-RPTP family members maintain synapse formation to coordinate excitatory-inhibitory balance.
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Affiliation(s)
- Yeong Shin Yim
- Department of Pharmacology, Brain Research Institute, Brain Korea 21 Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Younghee Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea; and
| | - Jungyong Nam
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Hong In Yoon
- Department of Pharmacology, Brain Research Institute, Brain Korea 21 Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Kangduk Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea; and
| | - Dong Goo Kim
- Department of Pharmacology, Brain Research Institute, Brain Korea 21 Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Chul Hoon Kim
- Department of Pharmacology, Brain Research Institute, Brain Korea 21 Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Jaewon Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea; and
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95
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Abstract
An important organizing feature of the CNS is that individual neurons receive input from many different sources. Independent regulation of synaptic input is critical for the function and adaptive responses of the nervous system, but the underlying molecular mechanisms are not well understood. We identify the leucine-rich repeat (LRR)-containing protein NGL-2 (Lrrc4) as a key regulator of input-specific synapse development in the hippocampus. Using genetic deletion and shRNA-mediated knockdown, we demonstrate a role for NGL-2 in regulating the strength of synaptic transmission and spine density specifically at Schaffer collateral synapses in the stratum radiatum (SR) in CA1. NGL-2 protein is restricted to SR and spine regulation requires NGL-2's LRR and PDZ-binding domains. Finally, loss of NGL-2 disrupts cooperative interactions between distal and proximal synapses in CA1 pyramidal cells. These results demonstrate that NGL-2 is critical for pathway-specific synapse development and functional integration of distinct inputs.
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96
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Zeitz C, Jacobson S, Hamel C, Bujakowska K, Neuillé M, Orhan E, Zanlonghi X, Lancelot ME, Michiels C, Schwartz S, Bocquet B, Antonio A, Audier C, Letexier M, Saraiva JP, Luu T, Sennlaub F, Nguyen H, Poch O, Dollfus H, Lecompte O, Kohl S, Sahel JA, Bhattacharya S, Audo I, Audo I. Whole-exome sequencing identifies LRIT3 mutations as a cause of autosomal-recessive complete congenital stationary night blindness. Am J Hum Genet 2013; 92:67-75. [PMID: 23246293 DOI: 10.1016/j.ajhg.2012.10.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/12/2012] [Accepted: 10/25/2012] [Indexed: 11/25/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous retinal disorder. Two forms can be distinguished clinically: complete CSNB (cCSNB) and incomplete CSNB. Individuals with cCSNB have visual impairment under low-light conditions and show a characteristic electroretinogram (ERG). The b-wave amplitude is severely reduced in the dark-adapted state of the ERG, representing abnormal function of ON bipolar cells. Furthermore, individuals with cCSNB can show other ocular features such as nystagmus, myopia, and strabismus and can have reduced visual acuity and abnormalities of the cone ERG waveform. The mode of inheritance of this form can be X-linked or autosomal recessive, and the dysfunction of four genes (NYX, GRM6, TRPM1, and GPR179) has been described so far. Whole-exome sequencing in one simplex cCSNB case lacking mutations in the known genes led to the identification of a missense mutation (c.983G>A [p.Cys328Tyr]) and a nonsense mutation (c.1318C>T [p.Arg440(∗)]) in LRIT3, encoding leucine-rich-repeat (LRR), immunoglobulin-like, and transmembrane-domain 3 (LRIT3). Subsequent Sanger sequencing of 89 individuals with CSNB identified another cCSNB case harboring a nonsense mutation (c.1151C>G [p.Ser384(∗)]) and a deletion predicted to lead to a premature stop codon (c.1538_1539del [p.Ser513Cysfs(∗)59]) in the same gene. Human LRIT3 antibody staining revealed in the outer plexiform layer of the human retina a punctate-labeling pattern resembling the dendritic tips of bipolar cells; similar patterns have been observed for other proteins implicated in cCSNB. The exact role of this LRR protein in cCSNB remains to be elucidated.
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97
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Fox AS, Oler JA, Shelton SE, Nanda SA, Davidson RJ, Roseboom PH, Kalin NH. Central amygdala nucleus (Ce) gene expression linked to increased trait-like Ce metabolism and anxious temperament in young primates. Proc Natl Acad Sci U S A 2012; 109:18108-13. [PMID: 23071305 PMCID: PMC3497741 DOI: 10.1073/pnas.1206723109] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Children with anxious temperament (AT) are particularly sensitive to new social experiences and have increased risk for developing anxiety and depression. The young rhesus monkey is optimal for studying the origin of human AT because it shares with humans the genetic, neural, and phenotypic underpinnings of complex social and emotional functioning. In vivo imaging in young monkeys demonstrated that central nucleus of the amygdala (Ce) metabolism is relatively stable across development and predicts AT. Transcriptome-wide gene expression, which reflects combined genetic and environmental influences, was assessed within the Ce. Results support a maladaptive neurodevelopmental hypothesis linking decreased amygdala neuroplasticity to early-life dispositional anxiety. For example, high AT individuals had decreased mRNA expression of neurotrophic tyrosine kinase, receptor, type 3 (NTRK3). Moreover, variation in Ce NTRK3 expression was inversely correlated with Ce metabolism and other AT-substrates. These data suggest that altered amygdala neuroplasticity may play a role the early dispositional risk to develop anxiety and depression.
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Affiliation(s)
- Andrew S. Fox
- Departments of Psychology and
- HealthEmotions Research Institute, University of Wisconsin, Madison, WI 53719; and
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin, Madison, WI 53705
| | - Jonathan A. Oler
- Psychiatry and
- HealthEmotions Research Institute, University of Wisconsin, Madison, WI 53719; and
| | - Steven E. Shelton
- Psychiatry and
- HealthEmotions Research Institute, University of Wisconsin, Madison, WI 53719; and
| | | | - Richard J. Davidson
- Departments of Psychology and
- Psychiatry and
- HealthEmotions Research Institute, University of Wisconsin, Madison, WI 53719; and
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin, Madison, WI 53705
| | | | - Ned H. Kalin
- Departments of Psychology and
- Psychiatry and
- HealthEmotions Research Institute, University of Wisconsin, Madison, WI 53719; and
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin, Madison, WI 53705
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98
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Abstract
Identification of a postsynaptic protein in the hippocampus reveals how neurotransmitter release from one neuron is tailored to different target cells.
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Affiliation(s)
- Chris J McBain
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Porter Neuroscience Center, Room 3C903, Lincoln Drive, Bethesda, MD 20892, USA.
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99
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Sylwestrak EL, Ghosh A. Elfn1 regulates target-specific release probability at CA1-interneuron synapses. Science 2012; 338:536-40. [PMID: 23042292 DOI: 10.1126/science.1222482] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although synaptic transmission may be unidirectional, the establishment of synaptic connections with specific properties can involve bidirectional signaling. Pyramidal neurons in the hippocampus form functionally distinct synapses onto two types of interneurons. Excitatory synapses onto oriens-lacunosum moleculare (O-LM) interneurons are facilitating and have a low release probability, whereas synapses onto parvalbumin interneurons are depressing and have a high release probability. Here, we show that the extracellular leucine-rich repeat fibronectin containing 1 (Elfn1) protein is selectively expressed by O-LM interneurons and regulates presynaptic release probability to direct the formation of highly facilitating pyramidal-O-LM synapses. Thus, postsynaptic expression of Elfn1 in O-LM interneurons regulates presynaptic release probability, which confers target-specific synaptic properties to pyramidal cell axons.
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Affiliation(s)
- Emily L Sylwestrak
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0366, USA
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100
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Ko J. The leucine-rich repeat superfamily of synaptic adhesion molecules: LRRTMs and Slitrks. Mol Cells 2012; 34:335-40. [PMID: 22767246 PMCID: PMC3887770 DOI: 10.1007/s10059-012-0113-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/05/2012] [Accepted: 06/05/2012] [Indexed: 11/29/2022] Open
Abstract
Synapses are asymmetric intercellular junctions connected by multiple synaptic cell adhesion molecules (CAMs). Synaptic CAMs function in various stages of synaptogenesis - the process of synapse creation - encompassing synapse formation, maturation, refinement, plasticity, and elimination. The list of synaptic CAMs has rapidly grown, although their precise functions of most CAMs at synapses remain incomplete. Members of an emerging class of transmembrane proteins containing leucine-rich repeat (LRR) domains have received considerable recent research attention. In this minireview, I discuss recent findings on LRR-containing synaptic CAMs that impact synapse development and circuit formation, focusing on two families of LRR synaptic CAMs: leucine-rich transmembrane proteins (LRRTMs) and Slit and Trk-like family (Slitrks). Their basic biochemical properties, proposed functions at synapses, physiological significances, and open questions are summarized.
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Affiliation(s)
- Jaewon Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea.
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