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Han KA, Ko J. Orchestration of synaptic functions by WAVE regulatory complex-mediated actin reorganization. Exp Mol Med 2023; 55:1065-1075. [PMID: 37258575 PMCID: PMC10318009 DOI: 10.1038/s12276-023-01004-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 06/02/2023] Open
Abstract
The WAVE regulatory complex (WRC), composed of five components-Cyfip1/Sra1, WAVE/Scar, Abi, Nap1/Nckap1, and Brk1/HSPC300-is essential for proper actin cytoskeletal dynamics and remodeling in eukaryotic cells, likely by matching various patterned signals to Arp2/3-mediated actin nucleation. Accumulating evidence from recent studies has revealed diverse functions of the WRC in neurons, demonstrating its crucial role in dictating the assembly of molecular complexes for the patterning of various trans-synaptic signals. In this review, we discuss recent exciting findings on the physiological role of the WRC in regulating synaptic properties and highlight the involvement of WRC dysfunction in various brain disorders.
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Affiliation(s)
- Kyung Ah Han
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988, Korea
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988, Korea.
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea.
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2
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Schneider F, Metz I, Rust MB. Regulation of actin filament assembly and disassembly in growth cone motility and axon guidance. Brain Res Bull 2023; 192:21-35. [PMID: 36336143 DOI: 10.1016/j.brainresbull.2022.10.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Directed outgrowth of axons is fundamental for the establishment of neuronal networks. Axon outgrowth is guided by growth cones, highly motile structures enriched in filamentous actin (F-actin) located at the axons' distal tips. Growth cones exploit F-actin-based protrusions to scan the environment for guidance cues, and they contain the sensory apparatus to translate guidance cue information into intracellular signaling cascades. These cascades act upstream of actin-binding proteins (ABP) and thereby control assembly and disassembly of F-actin. Spatiotemporally controlled F-actin dis-/assembly in growth cones steers the axon towards attractants and away from repellents, and it thereby navigates the axon through the developing nervous system. Hence, ABP that control F-actin dynamics emerged as critical regulators of neuronal network formation. In the present review article, we will summarize and discuss current knowledge of the mechanisms that control remodeling of the actin cytoskeleton in growth cones, focusing on recent progress in the field. Further, we will introduce tools and techniques that allow to study actin regulatory mechanism in growth cones.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Molecular Urooncology, Department of Urology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032 Marburg, Germany.
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3
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Zhao Y, Hua X, Bian Q, Wang D. Nanoplastic Exposure at Predicted Environmental Concentrations Induces Activation of Germline Ephrin Signal Associated with Toxicity Formation in the Caenorhabditis elegans Offspring. TOXICS 2022; 10:toxics10110699. [PMID: 36422907 PMCID: PMC9696181 DOI: 10.3390/toxics10110699] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 05/04/2023]
Abstract
In nematode Caenorhabditis elegans, exposure to polystyrene nanoparticles (PS-NPs) at predicted environmental concentrations can cause induction of transgenerational toxicity. However, the underlying mechanisms for toxicity formation of PS-NP in the offspring remain largely unknown. In this study, based on high-throughput sequencing, Ephrin ligand EFN-3 was identified as a target of KSR-1/2 (two kinase suppressors of Ras) in the germline during the control of transgenerational PS-NP toxicity. At parental generation (P0-G), exposure to 0.1-10 μg/L PS-NP caused the increase in expression of germline efn-3, and this increase in germline efn-3 expression could be further detected in the offspring, such as F1-G and F2-G. Germline RNAi of efn-3 caused a resistance to transgenerational PS-NP toxicity, suggesting that the activation of germline EFN-3 at P0-G mediated transgenerational PS-NP toxicity. In the offspring, Ephrin receptor VAB-1 was further activated by the increased EFN-3 caused by PS-NP exposure at P0-G, and RNAi of vab-1 also resulted in resistance to transgenerational PS-NP toxicity. VAB-1 acted in both the neurons and the germline to control toxicity of PS-NP in the offspring. In the neurons, VAB-1 regulated PS-NP toxicity by suppressing expressions of DBL-1, JNK-1, MPK-1, and GLB-10. In the germline, VAB-1 regulated PS-NP toxicity by increasing NDK-1 and LIN-23 expressions and decreasing EGL-1 expression. Therefore, germline Ephrin ligand EFN-3 and its receptor VAB-1 acted together to mediate the formation of transgenerational PS-NP toxicity. Our data highlight the important role of activation in germline Ephrin signals in mediating transgenerational toxicity of nanoplastics at predicted environmental concentrations in organisms.
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Affiliation(s)
- Yue Zhao
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China
| | - Xin Hua
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Qian Bian
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China
- Correspondence: (Q.B.); (D.W.)
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
- Shenzhen Ruipuxun Academy for Stem Cell & Regenerative Medicine, Shenzhen 518122, China
- Correspondence: (Q.B.); (D.W.)
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4
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Bhatia S, Hunter CP. SID-4/NCK-1 is important for dsRNA import in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2022; 12:6722623. [PMID: 36165710 PMCID: PMC9635667 DOI: 10.1093/g3journal/jkac252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 08/25/2022] [Indexed: 12/24/2022]
Abstract
RNA interference is sequence-specific gene silencing triggered by double-stranded RNA. Systemic RNA interference is where double-stranded RNA, expressed or introduced into 1 cell, is transported to and initiates RNA interference in other cells. Systemic RNA interference is very efficient in Caenorhabditis elegans and genetic screens for systemic RNA interference-defective mutants have identified RNA transporters (SID-1, SID-2, and SID-5) and a signaling protein (SID-3). Here, we report that SID-4 is nck-1, a C. elegans NCK-like adaptor protein. sid-4 null mutations cause a weak, dose-sensitive, systemic RNA interference defect and can be effectively rescued by SID-4 expression in target tissues only, implying a role in double-stranded RNA import. SID-4 and SID-3 (ACK-1 kinase) homologs interact in mammals and insects, suggesting that they may function in a common signaling pathway; however, a sid-3; sid-4 double mutants showed additive resistance to RNA interference, suggesting that these proteins likely interact with other signaling pathways as well. A bioinformatic screen coupled to RNA interference sensitivity tests identified 23 additional signaling components with weak RNA interference-defective phenotypes. These observations suggest that environmental conditions may modulate systemic RNA interference efficacy, and indeed, sid-3 and sid-4 are required for growth temperature effects on systemic RNA interference silencing efficiency.
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Affiliation(s)
- Sonya Bhatia
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138, USA
| | - Craig P Hunter
- Corresponding author: Department of Molecular and Cellular Biology, 16 Divinity Avenue, Harvard University, Cambridge MA, 02138 USA.
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5
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Kaplan N, Liu M, Wang J, Yang W, Fiolek E, Peng H, Lavker RM. Eph signaling is regulated by miRNA-210: Implications for corneal epithelial repair. FASEB J 2022; 36:e22076. [PMID: 34856019 PMCID: PMC8647904 DOI: 10.1096/fj.202101423r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/25/2021] [Accepted: 11/17/2021] [Indexed: 01/03/2023]
Abstract
A distinct boundary exists between the progenitor cells in the basal limbal epithelium and the more differentiated corneal epithelial basal cells. We have shown that reciprocal expression patterns of EphA2 and Ephrin-A1 are likely to contribute to normal limbal-corneal epithelial compartmentalization as well as play a role in response to injury. How this signaling axis is regulated remains unclear. We have demonstrated that microRNAs (miRNAs) play critical roles in corneal epithelial wound healing and several miRNAs (e.g. miR-210) have been predicted to target ephrins. Previous expression profiling experiments demonstrated that miR-210 is prominently expressed in corneal epithelial cells. RNA-seq data acquired from miR-210-depleted HCECs showed up-regulation of genes involved in cellular migration. In addition, miR-210 is decreased after corneal injury while EphA2 is increased. Moreover, antago-210-treated HCECs markedly enhanced wound closure in a scratch wound assay. Antago-210 treatment resulted in increased EphA2 protein levels as well as pS897-EphA2, the pro-migratory form of EphA2. As expected, Ephrin-A1 levels were reduced, while levels of a well-known target of miR-210, Ephrin-A3, were increased by antago-210 treatment. The increase in migration with antago-210 could be inhibited by Ephrin-A1 overexpression, Ephrin-A1-Fc treatment or siRNA depletion of EphA2. However, depletion of Ephrin-A3 did not have effects on the antago-210-induced increase in migration. In addition, Ephrin-A1 overexpression and siEphA2 dampened EGFR signaling, which is increased by antago-210. Our data clearly demonstrate a link between miR-210 and EphA2/Ephrin-A1 signaling that regulates, in part, corneal epithelial migration. This interaction might potentially control the limbal-corneal epithelial boundary.
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Affiliation(s)
- Nihal Kaplan
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA
| | - Min Liu
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA
| | - Junyi Wang
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA,Department of Ophthalmology, Ophthalmology and Visual Science Key Lab of PLA, Chinese PLA General Hospital, Beijing, China
| | - Wending Yang
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA
| | - Elaina Fiolek
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA
| | - Han Peng
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA,Correspondence: Robert M. Lavker, Ph.D., Department of Dermatology, Northwestern University, 303 East Chicago Avenue, Ward 9-124, Chicago, IL 60611, USA;
| | - Robert M. Lavker
- Department of Dermatology, Northwestern University, Chicago, IL, 60611, USA,Correspondence: Han Peng, Ph.D., Department of Dermatology, Northwestern University, 303 East Chicago Avenue, Ward 9-120, Chicago, IL 60611, USA;
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6
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Chen Z, Oh D, Biswas KH, Zaidel-Bar R, Groves JT. Probing the effect of clustering on EphA2 receptor signaling efficiency by subcellular control of ligand-receptor mobility. eLife 2021; 10:67379. [PMID: 34414885 PMCID: PMC8397371 DOI: 10.7554/elife.67379] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 08/19/2021] [Indexed: 11/29/2022] Open
Abstract
Clustering of ligand:receptor complexes on the cell membrane is widely presumed to have functional consequences for subsequent signal transduction. However, it is experimentally challenging to selectively manipulate receptor clustering without altering other biochemical aspects of the cellular system. Here, we develop a microfabrication strategy to produce substrates displaying mobile and immobile ligands that are separated by roughly 1 µm, and thus experience an identical cytoplasmic signaling state, enabling precision comparison of downstream signaling reactions. Applying this approach to characterize the ephrinA1:EphA2 signaling system reveals that EphA2 clustering enhances both receptor phosphorylation and downstream signaling activity. Single-molecule imaging clearly resolves increased molecular binding dwell times at EphA2 clusters for both Grb2:SOS and NCK:N-WASP signaling modules. This type of intracellular comparison enables a substantially higher degree of quantitative analysis than is possible when comparisons must be made between different cells and essentially eliminates the effects of cellular response to ligand manipulation.
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Affiliation(s)
- Zhongwen Chen
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China.,Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Dongmyung Oh
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch at Galveston, Galveston, United States.,Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Kabir Hassan Biswas
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
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7
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Javier-Torrent M, Marco S, Rocandio D, Pons-Vizcarra M, Janes PW, Lackmann M, Egea J, Saura CA. Presenilin/γ-secretase-dependent EphA3 processing mediates axon elongation through non-muscle myosin IIA. eLife 2019; 8:43646. [PMID: 31577226 PMCID: PMC6774734 DOI: 10.7554/elife.43646] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 09/18/2019] [Indexed: 01/08/2023] Open
Abstract
EphA/ephrin signaling regulates axon growth and guidance of neurons, but whether this process occurs also independently of ephrins is unclear. We show that presenilin-1 (PS1)/γ-secretase is required for axon growth in the developing mouse brain. PS1/γ-secretase mediates axon growth by inhibiting RhoA signaling and cleaving EphA3 independently of ligand to generate an intracellular domain (ICD) fragment that reverses axon defects in PS1/γ-secretase- and EphA3-deficient hippocampal neurons. Proteomic analysis revealed that EphA3 ICD binds to non-muscle myosin IIA (NMIIA) and increases its phosphorylation (Ser1943), which promotes NMIIA filament disassembly and cytoskeleton rearrangement. PS1/γ-secretase-deficient neurons show decreased phosphorylated NMIIA and NMIIA/actin colocalization. Moreover, pharmacological NMII inhibition reverses axon retraction in PS-deficient neurons suggesting that NMIIA mediates PS/EphA3-dependent axon elongation. In conclusion, PS/γ-secretase-dependent EphA3 cleavage mediates axon growth by regulating filament assembly through RhoA signaling and NMIIA, suggesting opposite roles of EphA3 on inhibiting (ligand-dependent) and promoting (receptor processing) axon growth in developing neurons.
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Affiliation(s)
- Míriam Javier-Torrent
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sergi Marco
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Daniel Rocandio
- Institut de Recerca Biomédica de Lleida, Universitat de Lleida, Lleida, Spain
| | - Maria Pons-Vizcarra
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Peter W Janes
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | - Martin Lackmann
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | - Joaquim Egea
- Institut de Recerca Biomédica de Lleida, Universitat de Lleida, Lleida, Spain
| | - Carlos A Saura
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Barcelona, Spain
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8
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Abstract
Cell surface transmembrane receptors often form nanometer- to micrometer-scale clusters to initiate signal transduction in response to environmental cues. Extracellular ligand oligomerization, domain-domain interactions, and binding to multivalent proteins all contribute to cluster formation. Here we review the current understanding of mechanisms driving cluster formation in a series of representative receptor systems: glycosylated receptors, immune receptors, cell adhesion receptors, Wnt receptors, and receptor tyrosine kinases. We suggest that these clusters share properties of systems that undergo liquid-liquid phase separation and could be investigated in this light.
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Affiliation(s)
- Lindsay B Case
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; , ,
| | - Jonathon A Ditlev
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; , ,
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; , ,
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9
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Spatially modulated ephrinA1:EphA2 signaling increases local contractility and global focal adhesion dynamics to promote cell motility. Proc Natl Acad Sci U S A 2018; 115:E5696-E5705. [PMID: 29866846 DOI: 10.1073/pnas.1719961115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent studies have revealed pronounced effects of the spatial distribution of EphA2 receptors on cellular response to receptor activation. However, little is known about molecular mechanisms underlying this spatial sensitivity, in part due to lack of experimental systems. Here, we introduce a hybrid live-cell patterned supported lipid bilayer experimental platform in which the sites of EphA2 activation and integrin adhesion are spatially controlled. Using a series of live-cell imaging and single-molecule tracking experiments, we map the transmission of signals from ephrinA1:EphA2 complexes. Results show that ligand-dependent EphA2 activation induces localized myosin-dependent contractions while simultaneously increasing focal adhesion dynamics throughout the cell. Mechanistically, Src kinase is activated at sites of ephrinA1:EphA2 clustering and subsequently diffuses on the membrane to focal adhesions, where it up-regulates FAK and paxillin tyrosine phosphorylation. EphrinA1:EphA2 signaling triggers multiple cellular responses with differing spatial dependencies to enable a directed migratory response to spatially resolved contact with ephrinA1 ligands.
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10
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Liao CP, Li H, Lee HH, Chien CT, Pan CL. Cell-Autonomous Regulation of Dendrite Self-Avoidance by the Wnt Secretory Factor MIG-14/Wntless. Neuron 2018; 98:320-334.e6. [DOI: 10.1016/j.neuron.2018.03.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/06/2018] [Accepted: 03/16/2018] [Indexed: 11/26/2022]
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11
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Borgen MA, Wang D, Grill B. RPM-1 regulates axon termination by affecting growth cone collapse and microtubule stability. Development 2017; 144:4658-4672. [PMID: 29084805 DOI: 10.1242/dev.154187] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 10/21/2017] [Indexed: 12/14/2022]
Abstract
Axon termination is essential for efficient and accurate nervous system construction. At present, relatively little is known about how growth cone collapse occurs prior to axon termination in vivo Using the mechanosensory neurons of C. elegans, we found collapse prior to axon termination is protracted, with the growth cone transitioning from a dynamic to a static state. Growth cone collapse prior to termination is facilitated by the signaling hub RPM-1. Given the prominence of the cytoskeleton in growth cone collapse, we assessed the relationship between RPM-1 and regulators of actin dynamics and microtubule stability. Our results reveal several important findings about how axon termination is orchestrated: (1) RPM-1 functions in parallel to RHO-1 and CRMP/UNC-33, but is suppressed by the Rac isoform MIG-2; (2) RPM-1 opposes the function of microtubule stabilizers, including tubulin acetyltransferases; and (3) genetic epistasis suggests the microtubule-stabilizing protein Tau/PTL-1 potentially inhibits RPM-1. These findings provide insight into how growth cone collapse is regulated during axon termination in vivo, and suggest that RPM-1 signaling destabilizes microtubules to facilitate growth cone collapse and axon termination.
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Affiliation(s)
- Melissa A Borgen
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Dandan Wang
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
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12
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Abstract
Many fundamental biological discoveries have been made in Caenorhabditis elegans. The discovery of Orsay virus has enabled studies of host-virus interactions in this model organism. To identify host factors critical for Orsay virus infection, we designed a forward genetic screen that utilizes a virally induced green fluorescent protein (GFP) reporter. Following chemical mutagenesis, two Viro (virus induced reporter off) mutants that failed to express GFP were mapped to sid-3, a nonreceptor tyrosine kinase, and B0280.13 (renamed viro-2), an ortholog of human Wiskott-Aldrich syndrome protein (WASP). Both mutants yielded Orsay virus RNA levels comparable to that of the residual input virus, suggesting that they are not permissive for Orsay virus replication. In addition, we demonstrated that both genes affect an early prereplication stage of Orsay virus infection. Furthermore, it is known that the human ortholog of SID-3, activated CDC42-associated kinase (ACK1/TNK2), is capable of phosphorylating human WASP, suggesting that VIRO-2 may be a substrate for SID-3 in C. elegans. A targeted RNA interference (RNAi) knockdown screen further identified the C. elegans gene nck-1, which has a human ortholog that interacts with TNK2 and WASP, as required for Orsay virus infection. Thus, genetic screening in C. elegans identified critical roles in virus infection for evolutionarily conserved genes in a known human pathway. Orsay virus is the only known virus capable of naturally infecting the model organism Caenorhabditis elegans, which shares many evolutionarily conserved genes with humans. We exploited the robust genetic tractability of C. elegans to identify three host genes, sid-3, viro-2, and nck-1, which are essential for Orsay virus infection. Mutant animals that lack these three genes are highly defective in viral replication. Strikingly, the human orthologs of these three genes, activated CDC42-associated kinase (TNK2), Wiskott-Aldrich syndrome protein (WASP), and noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) are part of a known signaling pathway in mammals. These results suggest that TNK2, WASP, and NCK1 may play important roles in mammalian virus infection.
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13
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Chisholm AD, Hutter H, Jin Y, Wadsworth WG. The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans. Genetics 2016; 204:849-882. [PMID: 28114100 PMCID: PMC5105865 DOI: 10.1534/genetics.115.186262] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
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Affiliation(s)
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, and
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
- Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and
| | - William G Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
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14
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Prospéri MT, Lépine P, Dingli F, Paul-Gilloteaux P, Martin R, Loew D, Knölker HJ, Coudrier E. Myosin 1b functions as an effector of EphB signaling to control cell repulsion. J Cell Biol 2016. [PMID: 26195670 PMCID: PMC4508888 DOI: 10.1083/jcb.201501018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myosin 1b functions as an effector of EphB2/ephrinB signaling and controls cell morphology and cell repulsion. Eph receptors and their membrane-tethered ligands, the ephrins, have important functions in embryo morphogenesis and in adult tissue homeostasis. Eph/ephrin signaling is essential for cell segregation and cell repulsion. This process is accompanied by morphological changes and actin remodeling that drives cell segregation and tissue patterning. The actin cortex must be mechanically coupled to the plasma membrane to orchestrate the cell morphology changes. Here, we demonstrate that myosin 1b that can mechanically link the membrane to the actin cytoskeleton interacts with EphB2 receptors via its tail and is tyrosine phosphorylated on its tail in an EphB2-dependent manner. Myosin 1b regulates the redistribution of myosin II in actomyosin fibers and the formation of filopodia at the interface of ephrinB1 and EphB2 cells, which are two processes mediated by EphB2 signaling that contribute to cell repulsion. Together, our results provide the first evidence that a myosin 1 functions as an effector of EphB2/ephrinB signaling, controls cell morphology, and thereby cell repulsion.
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Affiliation(s)
| | - Priscilla Lépine
- Institut Curie, Centre de Recherche, F-75248 Paris, France Université Pierre et Marie Curie, F-75252 Paris, France
| | - Florent Dingli
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Centre de Recherche, F-75248 Paris, France
| | - Perrine Paul-Gilloteaux
- Institut Curie, Centre de Recherche, F-75248 Paris, France Cell and Tissue Imaging Facility (PICT-IBiSA), Centre National de la Recherche Scientifique, UMR 144, Paris F-75248, France
| | - René Martin
- Department of Chemistry, Technische Univesität, 01069 Dresden, Germany
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Centre de Recherche, F-75248 Paris, France
| | | | - Evelyne Coudrier
- Institut Curie, Centre de Recherche, F-75248 Paris, France Cell and Tissue Imaging Facility (PICT-IBiSA), Centre National de la Recherche Scientifique, UMR 144, Paris F-75248, France
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15
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Mariani L, Lussi YC, Vandamme J, Riveiro A, Salcini AE. The H3K4me3/2 histone demethylase RBR-2 controls axon guidance by repressing the actin-remodeling gene wsp-1. Development 2016; 143:851-63. [PMID: 26811384 DOI: 10.1242/dev.132985] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/16/2016] [Indexed: 12/25/2022]
Abstract
The dynamic regulation of histone modifications is important for modulating transcriptional programs during development. Aberrant H3K4 methylation is associated with neurological disorders, but how the levels and the recognition of this modification affect specific neuronal processes is unclear. Here, we show that RBR-2, the sole homolog of the KDM5 family of H3K4me3/2 demethylases in Caenorhabditis elegans, ensures correct axon guidance by controlling the expression of the actin regulator wsp-1. Loss of rbr-2 results in increased levels of H3K4me3 at the transcriptional start site of wsp-1, with concomitant higher wsp-1 expression responsible for defective axon guidance. In agreement, overexpression of WSP-1 mimics rbr-2 loss, and its depletion restores normal axon guidance in rbr-2 mutants. NURF-1, an H3K4me3-binding protein and member of the chromatin-remodeling complex NURF, is required for promoting aberrant wsp-1 transcription in rbr-2 mutants and its ablation restores wild-type expression of wsp-1 and axon guidance. Thus, our results establish a precise role for epigenetic regulation in neuronal development by demonstrating a functional link between RBR-2 activity, H3K4me3 levels, the NURF complex and the expression of WSP-1.
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Affiliation(s)
- Luca Mariani
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Yvonne C Lussi
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Julien Vandamme
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Alba Riveiro
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anna Elisabetta Salcini
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark
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16
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Abstract
Actin filament networks assemble on cellular membranes in response to signals that locally activate neural Wiskott-Aldrich-syndrome protein (N-WASP) and the Arp2/3 complex. An inactive conformation of N-WASP is stabilized by intramolecular contacts between the GTPase binding domain (GBD) and the C helix of the verprolin-homology, connector-helix, acidic motif (VCA) segment. Multiple SH3 domain-containing adapter proteins can bind and possibly activate N-WASP, but it remains unclear how such binding events relieve autoinhibition to unmask the VCA segment and activate the Arp2/3 complex. Here, we have used purified components to reconstitute a signaling cascade driven by membrane-localized Src homology 3 (SH3) adapters and N-WASP, resulting in the assembly of dynamic actin networks. Among six SH3 adapters tested, Nck was the most potent activator of N-WASP-driven actin assembly. We identify within Nck a previously unrecognized activation motif in a linker between the first two SH3 domains. This linker sequence, reminiscent of bacterial virulence factors, directly engages the N-WASP GBD and competes with VCA binding. Our results suggest that animals, like pathogenic bacteria, have evolved peptide motifs that allosterically activate N-WASP, leading to localized actin nucleation on cellular membranes.
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17
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Norris AD, Sundararajan L, Morgan DE, Roberts ZJ, Lundquist EA. The UNC-6/Netrin receptors UNC-40/DCC and UNC-5 inhibit growth cone filopodial protrusion via UNC-73/Trio, Rac-like GTPases and UNC-33/CRMP. Development 2015; 141:4395-405. [PMID: 25371370 PMCID: PMC4302909 DOI: 10.1242/dev.110437] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
UNC-6/Netrin is a conserved axon guidance cue that can mediate both attraction and repulsion. We previously discovered that attractive UNC-40/DCC receptor signaling stimulates growth cone filopodial protrusion and that repulsive UNC-40–UNC-5 heterodimers inhibit filopodial protrusion in C. elegans. Here, we identify cytoplasmic signaling molecules required for UNC-6-mediated inhibition of filopodial protrusion involved in axon repulsion. We show that the Rac-like GTPases CED-10 and MIG-2, the Rac GTP exchange factor UNC-73/Trio, UNC-44/Ankyrin and UNC-33/CRMP act in inhibitory UNC-6 signaling. These molecules were required for the normal limitation of filopodial protrusion in developing growth cones and for inhibition of growth cone filopodial protrusion caused by activated MYR::UNC-40 and MYR::UNC-5 receptor signaling. Epistasis studies using activated CED-10 and MIG-2 indicated that UNC-44 and UNC-33 act downstream of the Rac-like GTPases in filopodial inhibition. UNC-73, UNC-33 and UNC-44 did not affect the accumulation of full-length UNC-5::GFP and UNC-40::GFP in growth cones, consistent with a model in which UNC-73, UNC-33 and UNC-44 influence cytoskeletal function during growth cone filopodial inhibition.
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Affiliation(s)
- Adam D Norris
- Programs in Genetics and Molecular, Cellular, and Developmental Biology, Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Lakshmi Sundararajan
- Programs in Genetics and Molecular, Cellular, and Developmental Biology, Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Dyan E Morgan
- Programs in Genetics and Molecular, Cellular, and Developmental Biology, Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Zachary J Roberts
- Programs in Genetics and Molecular, Cellular, and Developmental Biology, Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Erik A Lundquist
- Programs in Genetics and Molecular, Cellular, and Developmental Biology, Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
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18
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Cissé M, Checler F. Eph receptors: new players in Alzheimer's disease pathogenesis. Neurobiol Dis 2014; 73:137-49. [PMID: 25193466 DOI: 10.1016/j.nbd.2014.08.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/01/2014] [Accepted: 08/22/2014] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is devastating and leads to permanent losses of memory and other cognitive functions. Although recent genetic evidences strongly argue for a causative role of Aβ in AD onset and progression (Jonsson et al., 2012), its role in AD etiology remains a matter of debate. However, even if not the sole culprit or pathological trigger, genetic and anatomical evidences in conjunction with numerous pharmacological studies, suggest that Aβ peptides, at least contribute to the disease. How Aβ contributes to memory loss remains largely unknown. Soluble Aβ species referred to as Aβ oligomers have been shown to be neurotoxic and induce network failure and cognitive deficits in animal models of the disease. In recent years, several proteins were described as potential Aβ oligomers receptors, amongst which are the receptor tyrosine kinases of Eph family. These receptors together with their natural ligands referred to as ephrins have been involved in a plethora of physiological and pathological processes, including embryonic neurogenesis, learning and memory, diabetes, cancers and anxiety. Here we review recent discoveries on Eph receptors-mediated protection against Aβ oligomers neurotoxicity as well as their potential as therapeutic targets in AD pathogenesis.
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Affiliation(s)
- Moustapha Cissé
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275 CNRS/UNS, "Labex Distalz", 660 route des Lucioles, 06560, Sophia-Antipolis, Valbonne, France..
| | - Frédéric Checler
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275 CNRS/UNS, "Labex Distalz", 660 route des Lucioles, 06560, Sophia-Antipolis, Valbonne, France..
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19
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Klein R, Kania A. Ephrin signalling in the developing nervous system. Curr Opin Neurobiol 2014; 27:16-24. [PMID: 24608162 DOI: 10.1016/j.conb.2014.02.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/20/2014] [Accepted: 02/06/2014] [Indexed: 12/27/2022]
Abstract
Ephrin ligands and their Eph receptors hold our attention since their link to axon guidance almost twenty years ago. Since then, they have been shown to be critical for short distance cell-cell interactions in the nervous system. The interest in their function has not abated, leading to ever-more sophisticated studies generating as many surprising answers about their function as new questions. We discuss recent insights into their functions in the developing nervous system, including neuronal progenitor sorting, stochastic cell migration, guidance of neuronal growth cones, topographic map formation, as well as synaptic plasticity.
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Affiliation(s)
- Rüdiger Klein
- Department of Molecules - Signaling - Development, Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (Synergy), Munich, Germany.
| | - Artur Kania
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC, Canada H2W 1R7; Département de Médecine, Université de Montréal, Montréal, QC, Canada H3T 1J4; Division of Experimental Medicine, Departments of Biology, and, Anatomy and Cell Biology and Integrated Program in Neurosciences, McGill University, Montréal, QC, Canada H3A 1A3.
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20
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Marcette JD, Chen JJ, Nonet ML. The Caenorhabditis elegans microtubule minus-end binding homolog PTRN-1 stabilizes synapses and neurites. eLife 2014; 3:e01637. [PMID: 24569480 PMCID: PMC3930908 DOI: 10.7554/elife.01637] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Microtubule dynamics facilitate neurite growth and establish morphology, but the role of minus-end binding proteins in these processes is largely unexplored. CAMSAP homologs associate with microtubule minus-ends, and are important for the stability of epithelial cell adhesions. In this study, we report morphological defects in neurons and neuromuscular defects in mutants of the C. elegans CAMSAP, ptrn-1. Mechanosensory neurons initially extend wild-type neurites, and subsequently remodel by overextending neurites and retracting synaptic branches and presynaptic varicosities. This neuronal remodeling can be activated by mutations known to alter microtubules, and depends on a functioning DLK-1 MAP kinase pathway. We found that PTRN-1 localizes to both neurites and synapses, and our results suggest that alterations of microtubule structures caused by loss of PTRN-1 function activates a remodeling program leading to changes in neurite morphology. We propose a model whereby minus-end microtubule stabilization mediated by a functional PTRN-1 is necessary for morphological maintenance of neurons. DOI: http://dx.doi.org/10.7554/eLife.01637.001.
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Affiliation(s)
- Jana Dorfman Marcette
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, United States
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21
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Grossman EN, Giurumescu CA, Chisholm AD. Mechanisms of ephrin receptor protein kinase-independent signaling in amphid axon guidance in Caenorhabditis elegans. Genetics 2013; 195:899-913. [PMID: 23979582 PMCID: PMC3813872 DOI: 10.1534/genetics.113.154393] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/16/2013] [Indexed: 12/30/2022] Open
Abstract
Eph receptors and their ephrin ligands are key conserved regulators of axon guidance and can function in a variety of signaling modes. Here we analyze the genetic and cellular requirements for Eph signaling in a Caenorhabditis elegans axon guidance choice point, the ventral guidance of axons in the amphid commissure. The C. elegans Eph receptor EFN-1 has both kinase-dependent and kinase-independent roles in amphid ventral guidance. Of the four C. elegans ephrins, we find that only EFN-1 has a major role in amphid axon ventral guidance, and signals in both a receptor kinase-dependent and kinase-independent manner. Analysis of EFN-1 and EFN-1 expression and tissue-specific requirements is consistent with a model in which VAB-1 acts in amphid neurons, interacting with EFN-1 expressed on surrounding cells. Unexpectedly, left-hand neurons are more strongly affected than right-hand neurons by loss of Eph signaling, indicating a previously undetected left-right asymmetry in the requirement for Eph signaling. By screening candidate genes involved in Eph signaling, we find that the Eph kinase-independent pathway involves the ABL-1 nonreceptor tyrosine kinase and possibly the phosphatidylinositol 3-kinase pathway. Overexpression of ABL-1 is sufficient to rescue EFN-1 ventral guidance defects cell autonomously. Our results reveal new aspects of Eph signaling in a single axon guidance decision in vivo.
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Affiliation(s)
- Emily N. Grossman
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California 92093
| | - Claudiu A. Giurumescu
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California 92093
| | - Andrew D. Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California 92093
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22
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Insulin activates the insulin receptor to downregulate the PTEN tumour suppressor. Oncogene 2013; 33:3878-85. [DOI: 10.1038/onc.2013.347] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 07/09/2013] [Accepted: 07/15/2013] [Indexed: 12/26/2022]
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23
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Soreq L, Salomonis N, Bronstein M, Greenberg DS, Israel Z, Bergman H, Soreq H. Small RNA sequencing-microarray analyses in Parkinson leukocytes reveal deep brain stimulation-induced splicing changes that classify brain region transcriptomes. Front Mol Neurosci 2013; 6:10. [PMID: 23717260 PMCID: PMC3652308 DOI: 10.3389/fnmol.2013.00010] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/16/2013] [Indexed: 12/22/2022] Open
Abstract
MicroRNAs (miRNAs) are key post transcriptional regulators of their multiple target genes. However, the detailed profile of miRNA expression in Parkinson's disease, the second most common neurodegenerative disease worldwide and the first motor disorder has not been charted yet. Here, we report comprehensive miRNA profiling by next-generation small-RNA sequencing, combined with targets inspection by splice-junction and exon arrays interrogating leukocyte RNA in Parkinson's disease patients before and after deep brain stimulation (DBS) treatment and of matched healthy control volunteers (HC). RNA-Seq analysis identified 254 miRNAs and 79 passenger strand forms as expressed in blood leukocytes, 16 of which were modified in patients pre-treatment as compared to HC. 11 miRNAs were modified following brain stimulation 5 of which were changed inversely to the disease induced changes. Stimulation cessation further induced changes in 11 miRNAs. Transcript isoform abundance analysis yielded 332 changed isoforms in patients compared to HC, which classified brain transcriptomes of 47 PD and control independent microarrays. Functional enrichment analysis highlighted mitochondrion organization. DBS induced 155 splice changes, enriched in ubiquitin homeostasis. Cellular composition analysis revealed immune cell activity pre and post treatment. Overall, 217 disease and 74 treatment alternative isoforms were predictably targeted by modified miRNAs within both 3′ and 5′ untranslated ends and coding sequence sites. The stimulation-induced network sustained 4 miRNAs and 7 transcripts of the disease network. We believe that the presented dynamic networks provide a novel avenue for identifying disease and treatment-related therapeutic targets. Furthermore, the identification of these networks is a major step forward in the road for understanding the molecular basis for neurological and neurodegenerative diseases and assessment of the impact of brain stimulation on human diseases.
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Affiliation(s)
- Lilach Soreq
- Department of Medical Neurobiology, Hadassah Faculty of Medicine, The Hebrew University of Jerusalem Jerusalem, Israel
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24
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A systematic analysis of genomic changes in Tg2576 mice. Mol Neurobiol 2012; 47:883-91. [PMID: 23242760 DOI: 10.1007/s12035-012-8384-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 12/04/2012] [Indexed: 10/27/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by intelligence decline, behavioral disorders and cognitive disability. The purpose of this study was to investigate gene expression in AD, based on published microarray data on Tg2576 mice. Hierarchical Cluster Analysis and Gene Ontology were employed to group genes together on the basis of their product characteristics and annotation data. Genes with prominent alterations were clustered into apoptosis and axon guidance pathways. Based on our findings and those of previous studies, we propose that the mitochondria-mediated apoptotic pathway plays a crucial role in the neuronal loss and synaptic dysfunction associated with AD. Furthermore, based on the findings of Positional Gene Enrichment analysis and Gene Set Enrichment analysis, we propose that the regulation of transcription of AD genes may be an important pathogenic factor in this neurodegenerative disease. Our results highlight the importance of genes that could subsequently be examined for their potential as prognostic markers for AD.
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25
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Miller MA, Chin-Sang ID. Eph receptor signaling in C. elegans. WORMBOOK : THE ONLINE REVIEW OF C. ELEGANS BIOLOGY 2012. [PMID: 23197476 DOI: 10.1895/wormbook.1.151.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Eph receptor protein-tyrosine kinases are among the oldest known animal receptors and have greatly expanded in number during vertebrate evolution. Their complex transduction mechanisms are capable of bidirectional and bimodal (multi-response) signaling. Eph receptors are expressed in almost every cell type in the human body, yet their roles in development, physiology, and disease are incompletely understood. Studies in C. elegans have helped identify biological functions of these receptors, as well as transduction mechanisms. Here we review advances in our understanding of Eph receptor signaling made using the C. elegans model system.
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Affiliation(s)
- Michael A Miller
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA.
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26
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Pesti S, Balázs A, Udupa R, Szabó B, Fekete A, Bőgel G, Buday L. Complex formation of EphB1/Nck/Caskin1 leads to tyrosine phosphorylation and structural changes of the Caskin1 SH3 domain. Cell Commun Signal 2012. [PMID: 23181695 PMCID: PMC3549760 DOI: 10.1186/1478-811x-10-36] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Scaffold proteins have an important role in the regulation of signal propagation. These proteins do not possess any enzymatic activity but can contribute to the formation of multiprotein complexes. Although scaffold proteins are present in all cell types, the nervous system contains them in the largest amount. Caskin proteins are typically present in neuronal cells, particularly, in the synapses. However, the signaling mechanisms by which Caskin proteins are regulated are largely unknown. Results Here we demonstrate that EphB1 receptor tyrosine kinase can recruit Caskin1 through the adaptor protein Nck. Upon activation of the receptor kinase, the SH2 domain of Nck binds to one of its tyrosine residues, while Nck SH3 domains interact with the proline-rich domain of Caskin1. Complex formation of the receptor, adaptor and scaffold proteins results in the tyrosine phosphorylation of Caskin1 on its SH3 domain. The phosphorylation sites were identified by mass-spectrometry as tyrosines 296 and 336. To reveal the structural consequence of this phosphorylation, CD spectroscopy was performed. This measurement suggests that upon tyrosine phosphorylation the structure of the Caskin1 SH3 domain changes significantly. Conclusion Taken together, we propose that the scaffold protein Caskin1 can form a complex with the EphB1 tyrosine kinase via the Nck protein as a linker. Complex formation results in tyrosine phosphorylation of the Caskin1 SH3 domain. Although we were not able to identify any physiological partner of the SH3 domain so far, we could demonstrate that phosphorylation on conserved tyrosine residues results in marked changes in the structure of the SH3 domain.
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Affiliation(s)
- Szabolcs Pesti
- From the Department of Medical Chemistry, Semmelweis University Medical School, Budapest, 1094, Hungary.
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27
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Bernadskaya YY, Wallace A, Nguyen J, Mohler WA, Soto MC. UNC-40/DCC, SAX-3/Robo, and VAB-1/Eph polarize F-actin during embryonic morphogenesis by regulating the WAVE/SCAR actin nucleation complex. PLoS Genet 2012; 8:e1002863. [PMID: 22876199 PMCID: PMC3410845 DOI: 10.1371/journal.pgen.1002863] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 06/12/2012] [Indexed: 01/10/2023] Open
Abstract
Many cells in a developing embryo, including neurons and their axons and growth cones, must integrate multiple guidance cues to undergo directed growth and migration. The UNC-6/netrin, SLT-1/slit, and VAB-2/Ephrin guidance cues, and their receptors, UNC-40/DCC, SAX-3/Robo, and VAB-1/Eph, are known to be major regulators of cellular growth and migration. One important area of research is identifying the molecules that interpret this guidance information downstream of the guidance receptors to reorganize the actin cytoskeleton. However, how guidance cues regulate the actin cytoskeleton is not well understood. We report here that UNC-40/DCC, SAX-3/Robo, and VAB-1/Eph differentially regulate the abundance and subcellular localization of the WAVE/SCAR actin nucleation complex and its activator, Rac1/CED-10, in the Caenorhabditis elegans embryonic epidermis. Loss of any of these three pathways results in embryos that fail embryonic morphogenesis. Similar defects in epidermal enclosure have been observed when CED-10/Rac1 or the WAVE/SCAR actin nucleation complex are missing during embryonic development in C. elegans. Genetic and molecular experiments demonstrate that in fact, these three axonal guidance proteins differentially regulate the levels and membrane enrichment of the WAVE/SCAR complex and its activator, Rac1/CED-10, in the epidermis. Live imaging of filamentous actin (F-actin) in embryos developing in the absence of individual guidance receptors shows that high levels of F-actin are not essential for polarized cell migrations, but that properly polarized distribution of F-actin is essential. These results suggest that proper membrane recruitment and activation of CED-10/Rac1 and of WAVE/SCAR by signals at the plasma membrane result in polarized F-actin that permits directed movements and suggest how multiple guidance cues can result in distinct changes in actin nucleation during morphogenesis.
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Affiliation(s)
- Yelena Y. Bernadskaya
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry New Jersey, Piscataway, New Jersey, United States of America
| | - Andre Wallace
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry New Jersey, Piscataway, New Jersey, United States of America
| | - Jillian Nguyen
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry New Jersey, Piscataway, New Jersey, United States of America
| | - William A. Mohler
- Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Martha C. Soto
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry New Jersey, Piscataway, New Jersey, United States of America
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