1
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Lee PH, Anaya M, Ladinsky MS, Reitsma J, Zinn K. An extracellular vesicle targeting ligand that binds to Arc proteins and facilitates Arc transport in vivo. eLife 2023; 12:e82874. [PMID: 37326306 DOI: 10.7554/elife.82874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 06/15/2023] [Indexed: 06/17/2023] Open
Abstract
Communication between distant cells can be mediated by extracellular vesicles (EVs) that deliver proteins and RNAs to recipient cells. Little is known about how EVs are targeted to specific cell types. Here we identify the Drosophila cell-surface protein Stranded at second (Sas) as a targeting ligand for EVs. Full-length Sas is present in EV preparations from transfected Drosophila Schneider 2 (S2) cells. Sas is a binding partner for the Ptp10D receptor tyrosine phosphatase, and Sas-bearing EVs preferentially target to cells expressing Ptp10D. We used co-immunoprecipitation and peptide binding to show that the cytoplasmic domain (ICD) of Sas binds to dArc1 and mammalian Arc. dArc1 and Arc are related to retrotransposon Gag proteins. They form virus-like capsids which encapsulate Arc and other mRNAs and are transported between cells via EVs. The Sas ICD contains a motif required for dArc1 binding that is shared by the mammalian and Drosophila amyloid precursor protein (APP) orthologs, and the APP ICD also binds to mammalian Arc. Sas facilitates delivery of dArc1 capsids bearing dArc1 mRNA into distant Ptp10D-expressing recipient cells in vivo.
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Affiliation(s)
- Peter H Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Michael Anaya
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Mark S Ladinsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | | | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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2
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Ma D, Herndon N, Le JQ, Abruzzi KC, Zinn K, Rosbash M. Neural connectivity molecules best identify the heterogeneous clock and dopaminergic cell types in the Drosophila adult brain. Sci Adv 2023; 9:eade8500. [PMID: 36812309 PMCID: PMC9946362 DOI: 10.1126/sciadv.ade8500] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/26/2023] [Indexed: 05/25/2023]
Abstract
Our recent single-cell sequencing of most adult Drosophila circadian neurons indicated notable and unexpected heterogeneity. To address whether other populations are similar, we sequenced a large subset of adult brain dopaminergic neurons. Their gene expression heterogeneity is similar to that of clock neurons, i.e., both populations have two to three cells per neuron group. There was also unexpected cell-specific expression of neuron communication molecule messenger RNAs: G protein-coupled receptor or cell surface molecule (CSM) transcripts alone can define adult brain dopaminergic and circadian neuron cell type. Moreover, the adult expression of the CSM DIP-beta in a small group of clock neurons is important for sleep. We suggest that the common features of circadian and dopaminergic neurons are general, essential for neuronal identity and connectivity of the adult brain, and that these features underlie the complex behavioral repertoire of Drosophila.
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Affiliation(s)
- Dingbang Ma
- Howard Hughes Medical Institute and Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Nicholas Herndon
- Howard Hughes Medical Institute and Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Jasmine Quynh Le
- Howard Hughes Medical Institute and Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Katharine C. Abruzzi
- Howard Hughes Medical Institute and Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Michael Rosbash
- Howard Hughes Medical Institute and Department of Biology, Brandeis University, Waltham, MA 02454, USA
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3
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Siepe DH, Henneberg LT, Wilson SC, Hess GT, Bassik MC, Zinn K, Garcia KC. Identification of orphan ligand-receptor relationships using a cell-based CRISPRa enrichment screening platform. eLife 2022; 11:e81398. [PMID: 36178190 PMCID: PMC9578707 DOI: 10.7554/elife.81398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 09/29/2022] [Indexed: 11/20/2022] Open
Abstract
Secreted proteins, which include cytokines, hormones, and growth factors, are extracellular ligands that control key signaling pathways mediating cell-cell communication within and between tissues and organs. Many drugs target secreted ligands and their cell surface receptors. Still, there are hundreds of secreted human proteins that either have no identified receptors ('orphans') or are likely to act through cell surface receptors that have not yet been characterized. Discovery of secreted ligand-receptor interactions by high-throughput screening has been problematic, because the most commonly used high-throughput methods for protein-protein interaction (PPI) screening are not optimized for extracellular interactions. Cell-based screening is a promising technology for the deorphanization of ligand-receptor interactions, because multimerized ligands can enrich for cells expressing low affinity cell surface receptors, and such methods do not require purification of receptor extracellular domains. Here, we present a proteo-genomic cell-based CRISPR activation (CRISPRa) enrichment screening platform employing customized pooled cell surface receptor sgRNA libraries in combination with a magnetic bead selection-based enrichment workflow for rapid, parallel ligand-receptor deorphanization. We curated 80 potentially high-value orphan secreted proteins and ultimately screened 20 secreted ligands against two cell sgRNA libraries with targeted expression of all single-pass (TM1) or multi-pass transmembrane (TM2+) receptors by CRISPRa. We identified previously unknown interactions in 12 of these screens, and validated several of them using surface plasmon resonance and/or cell binding assays. The newly deorphanized ligands include three receptor protein tyrosine phosphatase (RPTP) ligands and a chemokine-like protein that binds to killer immunoglobulin-like receptors (KIRs). These new interactions provide a resource for future investigations of interactions between the human-secreted and membrane proteomes.
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Affiliation(s)
- Dirk H Siepe
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Lukas T Henneberg
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Steven C Wilson
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Gaelen T Hess
- Stanford ChEM-H, Department of Genetics, Stanford UniversityStanfordUnited States
| | - Michael C Bassik
- Stanford ChEM-H, Department of Genetics, Stanford UniversityStanfordUnited States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Howard Hughes Medical Institute, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
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4
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Jacobs M, Geiger M, Summers S, Janes T, Boyea R, Zinn K, Aburashed R, Spence D. Interferon-β Decreases the Hypermetabolic State of Red Blood Cells from Patients with Multiple Sclerosis. ACS Chem Neurosci 2022; 13:2658-2665. [PMID: 35946788 DOI: 10.1021/acschemneuro.2c00332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Multiple sclerosis (MS) is an inflammatory disease characterized by damage to the myelin sheath surrounding axons in the central nervous system. While the exact mechanism of this destruction is unknown, excess nitric oxide (NO) and adenosine triphosphate (ATP) have been measured in tissues and fluids obtained from people with MS. Here, incubation of interferon-beta (IFN-β), an MS drug with an unknown mechanism of action, with red blood cells (RBCs) obtained from people with MS provide evidence of a potential hypermetabolic state in the MS RBC that is decreased with IFN-β intervention. Specifically, binding of all three components of an albumin/C-peptide/Zn2+ complex to MS RBCs was significantly increased in comparison to control RBCs. For example, the binding of C-peptide to MS RBCs was significantly increased (3.4 ± 0.1 nM) compared to control RBCs (1.6 ± 0.2 nM). However, C-peptide binding to MS RBCs was reduced to a value (1.6 ± 0.3 nM) statistically equal to that of control RBCs in the presence of 2 nM IFN-β. Similar trends were measured for albumin and Zn2+ binding to RBCs when in the presence of IFN-β. RBC function was also affected by incubation of cells with IFN-β. Specifically, RBC-derived ATP and measurable membrane GLUT1 were both significantly decreased (56 and 24%, respectively) in the presence of IFN-β. Collectively, our results suggest that IFN-β inhibits albumin binding to the RBC, thereby reducing its ability to deliver ligands such as C-peptide and Zn2+ to the cell and normalizing the basal hypermetabolic state.
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Affiliation(s)
- M Jacobs
- Department of Comparative Medicine and Integrative Biology, Michigan State University, East Lansing, Michigan 48824, United States.,Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - M Geiger
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.,Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - S Summers
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, United States.,Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - T Janes
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - R Boyea
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - K Zinn
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, United States.,Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - R Aburashed
- Memorial Healthcare Institute for Neuroscience, Michigan State University, East Lansing, Michigan 48824, United States
| | - D Spence
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, United States.,Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
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5
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Xu S, Sergeeva AP, Katsamba PS, Mannepalli S, Bahna F, Bimela J, Zipursky SL, Shapiro L, Honig B, Zinn K. Affinity requirements for control of synaptic targeting and neuronal cell survival by heterophilic IgSF cell adhesion molecules. Cell Rep 2022; 39:110618. [PMID: 35385751 PMCID: PMC9078203 DOI: 10.1016/j.celrep.2022.110618] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 02/01/2022] [Accepted: 03/14/2022] [Indexed: 11/24/2022] Open
Abstract
Neurons in the developing brain express many different cell adhesion molecules (CAMs) on their surfaces. CAM-binding affinities can vary by more than 200-fold, but the significance of these variations is unknown. Interactions between the immunoglobulin superfamily CAM DIP-α and its binding partners, Dpr10 and Dpr6, control synaptic targeting and survival of Drosophila optic lobe neurons. We design mutations that systematically change interaction affinity and analyze function in vivo. Reducing affinity causes loss-of-function phenotypes whose severity scales with the magnitude of the change. Synaptic targeting is more sensitive to affinity reduction than is cell survival. Increasing affinity rescues neurons that would normally be culled by apoptosis. By manipulating CAM expression together with affinity, we show that the key parameter controlling circuit assembly is surface avidity, which is the strength of adherence between cell surfaces. We conclude that CAM binding affinities and expression levels are finely tuned for function during development.
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Affiliation(s)
- Shuwa Xu
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
| | - Alina P Sergeeva
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - Phinikoula S Katsamba
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Seetha Mannepalli
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Fabiana Bahna
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Jude Bimela
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Lawrence Shapiro
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Barry Honig
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA; Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Kai Zinn
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
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6
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Bali N, Lee HK(P, Zinn K. Sticks and Stones, a conserved cell surface ligand for the Type IIa RPTP Lar, regulates neural circuit wiring in Drosophila. eLife 2022; 11:e71469. [PMID: 35356892 PMCID: PMC9000958 DOI: 10.7554/elife.71469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Type IIa receptor-like protein tyrosine phosphatases (RPTPs) are essential for neural development. They have cell adhesion molecule (CAM)-like extracellular domains that interact with cell-surface ligands and coreceptors. We identified the immunoglobulin superfamily CAM Sticks and Stones (Sns) as a new partner for the Drosophila Type IIa RPTP Lar. Lar and Sns bind to each other in embryos and in vitro, and the human Sns ortholog, Nephrin, binds to human Type IIa RPTPs. Genetic analysis shows that Lar and Sns function together to regulate larval neuromuscular junction development, axon guidance in the mushroom body (MB), and innervation of the optic lobe (OL) medulla by R7 photoreceptors. In the neuromuscular system, Lar and Sns are both required in motor neurons, and may function as coreceptors. In the MB and OL, however, the relevant Lar-Sns interactions are in trans (between neurons), so Sns functions as a Lar ligand in these systems.
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Affiliation(s)
- Namrata Bali
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Hyung-Kook (Peter) Lee
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
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7
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Wojtowicz WM, Vielmetter J, Fernandes RA, Siepe DH, Eastman CL, Chisholm GB, Cox S, Klock H, Anderson PW, Rue SM, Miller JJ, Glaser SM, Bragstad ML, Vance J, Lam AW, Lesley SA, Zinn K, Garcia KC. A Human IgSF Cell-Surface Interactome Reveals a Complex Network of Protein-Protein Interactions. Cell 2021; 182:1027-1043.e17. [PMID: 32822567 PMCID: PMC7440162 DOI: 10.1016/j.cell.2020.07.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/19/2020] [Accepted: 07/17/2020] [Indexed: 12/17/2022]
Abstract
Cell-surface protein-protein interactions (PPIs) mediate cell-cell communication, recognition, and responses. We executed an interactome screen of 564 human cell-surface and secreted proteins, most of which are immunoglobulin superfamily (IgSF) proteins, using a high-throughput, automated ELISA-based screening platform employing a pooled-protein strategy to test all 318,096 PPI combinations. Screen results, augmented by phylogenetic homology analysis, revealed ∼380 previously unreported PPIs. We validated a subset using surface plasmon resonance and cell binding assays. Observed PPIs reveal a large and complex network of interactions both within and across biological systems. We identified new PPIs for receptors with well-characterized ligands and binding partners for “orphan” receptors. New PPIs include proteins expressed on multiple cell types and involved in diverse processes including immune and nervous system development and function, differentiation/proliferation, metabolism, vascularization, and reproduction. These PPIs provide a resource for further biological investigation into their functional relevance and may offer new therapeutic drug targets. Human IgSF interactome reveals complex network of cell-surface protein interactions Phylogenetic homology analysis predicts protein-protein interactions ∼380 previously unknown protein-protein interactions identified Deorphanization of receptors and new binding partners for well-studied receptors
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Affiliation(s)
- Woj M Wojtowicz
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Jost Vielmetter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ricardo A Fernandes
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dirk H Siepe
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Catharine L Eastman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gregory B Chisholm
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sarah Cox
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Heath Klock
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Paul W Anderson
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Sarah M Rue
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Jessica J Miller
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Scott M Glaser
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Melisa L Bragstad
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Julie Vance
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Annie W Lam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Scott A Lesley
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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8
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Brovero SG, Fortier JC, Hu H, Lovejoy PC, Newell NR, Palmateer CM, Tzeng RY, Lee PT, Zinn K, Arbeitman MN. Investigation of Drosophila fruitless neurons that express Dpr/DIP cell adhesion molecules. eLife 2021; 10:e63101. [PMID: 33616528 PMCID: PMC7972454 DOI: 10.7554/elife.63101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/22/2021] [Indexed: 12/16/2022] Open
Abstract
Drosophila reproductive behaviors are directed by fruitless neurons. A reanalysis of genomic studies shows that genes encoding dpr and DIP immunoglobulin superfamily (IgSF) members are expressed in fru P1 neurons. We find that each fru P1 and dpr/DIP (fru P1 ∩ dpr/DIP) overlapping expression pattern is similar in both sexes, but there are dimorphisms in neuronal morphology and cell number. Behavioral studies of fru P1 ∩ dpr/DIP perturbation genotypes indicate that the mushroom body functions together with the lateral protocerebral complex to direct courtship behavior. A single-cell RNA-seq analysis of fru P1 neurons shows that many DIPs have high expression in a small set of neurons, whereas the dprs are often expressed in a larger set of neurons at intermediate levels, with a myriad of dpr/DIP expression combinations. Functionally, we find that perturbations of sex hierarchy genes and of DIP-ε change the sex-specific morphologies of fru P1 ∩ DIP-α neurons.
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Affiliation(s)
- Savannah G Brovero
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Julia C Fortier
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Hongru Hu
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Pamela C Lovejoy
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Nicole R Newell
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Colleen M Palmateer
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Ruei-Ying Tzeng
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Michelle N Arbeitman
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
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9
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Affiliation(s)
- Namrata Bali
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, USA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, USA
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10
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Menon KP, Kulkarni V, Takemura SY, Anaya M, Zinn K. Interactions between Dpr11 and DIP-γ control selection of amacrine neurons in Drosophila color vision circuits. eLife 2019; 8:e48935. [PMID: 31692445 PMCID: PMC6879306 DOI: 10.7554/elife.48935] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/05/2019] [Indexed: 12/17/2022] Open
Abstract
Drosophila R7 UV photoreceptors (PRs) are divided into yellow (y) and pale (p) subtypes. yR7 PRs express the Dpr11 cell surface protein and are presynaptic to Dm8 amacrine neurons (yDm8) that express Dpr11's binding partner DIP-γ, while pR7 PRs synapse onto DIP-γ-negative pDm8. Dpr11 and DIP-γ expression patterns define 'yellow' and 'pale' color vision circuits. We examined Dm8 neurons in these circuits by electron microscopic reconstruction and expansion microscopy. DIP-γ and dpr11 mutations affect the morphologies of yDm8 distal ('home column') dendrites. yDm8 neurons are generated in excess during development and compete for presynaptic yR7 PRs, and interactions between Dpr11 and DIP-γ are required for yDm8 survival. These interactions also allow yDm8 neurons to select yR7 PRs as their appropriate home column partners. yDm8 and pDm8 neurons do not normally compete for survival signals or R7 partners, but can be forced to do so by manipulation of R7 subtype fate.
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Affiliation(s)
- Kaushiki P Menon
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Vivek Kulkarni
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Shin-ya Takemura
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
| | - Michael Anaya
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Kai Zinn
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
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11
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Bali N, Lee HK, Zinn K. Identification of four Drosophila Toll-related proteins as ligands for the PTP69D receptor tyrosine phosphatase. MicroPubl Biol 2019; 2019. [PMID: 32550457 PMCID: PMC7252352 DOI: 10.17912/micropub.biology.000159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Namrata Bali
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, USA
| | - Hyung-Kook Lee
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, USA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, USA
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12
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Ashley J, Sorrentino V, Lobb-Rabe M, Nagarkar-Jaiswal S, Tan L, Xu S, Xiao Q, Zinn K, Carrillo RA. Transsynaptic interactions between IgSF proteins DIP-α and Dpr10 are required for motor neuron targeting specificity. eLife 2019; 8:42690. [PMID: 30714906 PMCID: PMC6391064 DOI: 10.7554/elife.42690] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/31/2019] [Indexed: 12/27/2022] Open
Abstract
The Drosophila larval neuromuscular system provides an ideal context in which to study synaptic partner choice, because it contains a small number of pre- and postsynaptic cells connected in an invariant pattern. The discovery of interactions between two subfamilies of IgSF cell surface proteins, the Dprs and the DIPs, provided new candidates for cellular labels controlling synaptic specificity. Here we show that DIP-α is expressed by two identified motor neurons, while its binding partner Dpr10 is expressed by postsynaptic muscle targets. Removal of either DIP-α or Dpr10 results in loss of specific axonal branches and NMJs formed by one motor neuron, MNISN-1s, while other branches of the MNISN-1s axon develop normally. The temporal and spatial expression pattern of dpr10 correlates with muscle innervation by MNISN-1s during embryonic development. We propose a model whereby DIP-α and Dpr10 on opposing synaptic partners interact with each other to generate proper motor neuron connectivity.
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Affiliation(s)
- James Ashley
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoUnited States
| | - Violet Sorrentino
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoUnited States
| | - Meike Lobb-Rabe
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoUnited States,Graduate Program in Cell and Molecular BiologyUniversity of ChicagoChicagoUnited States
| | - Sonal Nagarkar-Jaiswal
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Liming Tan
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Shuwa Xu
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Qi Xiao
- Department of Biological ChemistryUniversity of California, Los AngelesLos AngelesUnited States
| | - Kai Zinn
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Robert A Carrillo
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoUnited States,Graduate Program in Cell and Molecular BiologyUniversity of ChicagoChicagoUnited States
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13
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Al-Anzi B, Zinn K. Identification and characterization of mushroom body neurons that regulate fat storage in Drosophila. Neural Dev 2018; 13:18. [PMID: 30103787 PMCID: PMC6090720 DOI: 10.1186/s13064-018-0116-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 07/27/2018] [Indexed: 12/02/2022] Open
Abstract
Background In an earlier study, we identified two neuronal populations, c673a and Fru-GAL4, that regulate fat storage in fruit flies. Both populations partially overlap with a structure in the insect brain known as the mushroom body (MB), which plays a critical role in memory formation. This overlap prompted us to examine whether the MB is also involved in fat storage homeostasis. Methods Using a variety of transgenic agents, we selectively manipulated the neural activity of different portions of the MB and associated neurons to decipher their roles in fat storage regulation. Results Our data show that silencing of MB neurons that project into the α’β’ lobes decreases de novo fatty acid synthesis and causes leanness, while sustained hyperactivation of the same neurons causes overfeeding and produces obesity. The α’β’ neurons oppose and dominate the fat regulating functions of the c673a and Fru-GAL4 neurons. We also show that MB neurons that project into the γ lobe also regulate fat storage, probably because they are a subset of the Fru neurons. We were able to identify input and output neurons whose activity affects fat storage, feeding, and metabolism. The activity of cholinergic output neurons that innervating the β’2 compartment (MBON-β’2mp and MBON-γ5β’2a) regulates food consumption, while glutamatergic output neurons innervating α’ compartments (MBON-γ2α’1 and MBON-α’2) control fat metabolism. Conclusions We identified a new fat storage regulating center, the α’β’ lobes of the MB. We also delineated the neuronal circuits involved in the actions of the α’β’ lobes, and showed that food intake and fat metabolism are controlled by separate sets of postsynaptic neurons that are segregated into different output pathways. Electronic supplementary material The online version of this article (10.1186/s13064-018-0116-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bader Al-Anzi
- Food & Nutrition Program, Environment & Life Sciences Research Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109, Kuwait City, Kuwait.
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
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Abou-Sena A, Boccaccini L, Ghidersa B, Zinn K. Characterization of the cooling channels of First Wall Mock-up dedicated to the HCPB TBM qualification. Fusion Engineering and Design 2017. [DOI: 10.1016/j.fusengdes.2017.02.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Li H, Watson A, Olechwier A, Anaya M, Sorooshyari SK, Harnett DP, Lee HKP, Vielmetter J, Fares MA, Garcia KC, Özkan E, Labrador JP, Zinn K. Deconstruction of the beaten Path-Sidestep interaction network provides insights into neuromuscular system development. eLife 2017; 6:28111. [PMID: 28829740 PMCID: PMC5578738 DOI: 10.7554/elife.28111] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/28/2017] [Indexed: 12/16/2022] Open
Abstract
An ‘interactome’ screen of all Drosophila cell-surface and secreted proteins containing immunoglobulin superfamily (IgSF) domains discovered a network formed by paralogs of Beaten Path (Beat) and Sidestep (Side), a ligand-receptor pair that is central to motor axon guidance. Here we describe a new method for interactome screening, the Bio-Plex Interactome Assay (BPIA), which allows identification of many interactions in a single sample. Using the BPIA, we ‘deorphanized’ four more members of the Beat-Side network. We confirmed interactions using surface plasmon resonance. The expression patterns of beat and side genes suggest that Beats are neuronal receptors for Sides expressed on peripheral tissues. side-VI is expressed in muscle fibers targeted by the ISNb nerve, as well as at growth cone choice points and synaptic targets for the ISN and TN nerves. beat-V genes, encoding Side-VI receptors, are expressed in ISNb and ISN motor neurons. Within every organ of the body, cells must be able to recognise and communicate with one another in order to work together to perform a particular role. Each cell has a specific protein on its surface that acts like a molecular identity card, and which can form weak bonds with a complementary protein on another cell. There are thousands of different cell surface proteins, and the interactions between them – known collectively as the interactome – dictate the how cells interact with one another. Many cell surface proteins are similar across species. Humans and fruit flies, for example, both possess a family of cell surface proteins that contain a region called the Immunoglobulin Superfamily domain. This family can be further divided into subfamilies, two of which are known as “Beats” and “Sides” for short. As the nervous system develops, nerve cells carrying a particular Beat protein interact with nerve or muscle cells carrying a corresponding Side protein. Yet while experiments have matched up many Beats and Sides, the partners of others remain unknown. Li et al. have now developed a new technique called the Bio-Plex Interactome Assay to rapidly screen for interactions between multiple cell surface proteins in a single sample. Applying the technique to cells from fruit flies revealed new binding partners within the Beats and the Sides. After verifying several of these interactions, Li et al. explored the role of various Beats and Sides in the developing nervous system of fruit fly embryos by mapping the cells that display them on their surfaces. This increased knowledge of the Beat-Side binding network should provide further insights into how connections form between nerve cells. The new screening technique could also eventually be used to map the cell surface protein interactome in humans. A number of key drugs, including the breast cancer drug Herceptin, target cell surface proteins. Identifying interactions among cell surface proteins could thus provide additional leads for developing new therapies.
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Affiliation(s)
- Hanqing Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Ash Watson
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland.,Institute of Neuroscience, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Agnieszka Olechwier
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
| | - Michael Anaya
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | | | - Dermott P Harnett
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland.,Institute of Neuroscience, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Hyung-Kook Peter Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Jost Vielmetter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Mario A Fares
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland.,Department of Abiotic Stress, Group of Integrative and Systems Biology, Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, United States.,Department of Structural Biology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, United States
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
| | - Juan-Pablo Labrador
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland.,Institute of Neuroscience, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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16
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Zinn K, Özkan E. Neural immunoglobulin superfamily interaction networks. Curr Opin Neurobiol 2017; 45:99-105. [PMID: 28558267 DOI: 10.1016/j.conb.2017.05.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/24/2017] [Accepted: 05/15/2017] [Indexed: 12/31/2022]
Abstract
The immunoglobulin superfamily (IgSF) encompasses hundreds of cell surface proteins containing multiple immunoglobulin-like (Ig) domains. Among these are neural IgCAMs, which are cell adhesion molecules that mediate interactions between cells in the nervous system. IgCAMs in some vertebrate IgSF subfamilies bind to each other homophilically and heterophilically, forming small interaction networks. In Drosophila, a global 'interactome' screen identified two larger networks in which proteins in one IgSF subfamily selectively interact with proteins in a different subfamily. One of these networks, the 'Dpr-ome', includes 30 IgSF proteins, each of which is expressed in a unique subset of neurons. Recent evidence shows that one interacting protein pair within the Dpr-ome network is required for development of the brain and neuromuscular system.
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Affiliation(s)
- Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, United States
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17
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Al-Anzi B, Gerges S, Olsman N, Ormerod C, Piliouras G, Ormerod J, Zinn K. Modeling and analysis of modular structure in diverse biological networks. J Theor Biol 2017; 422:18-30. [PMID: 28396125 DOI: 10.1016/j.jtbi.2017.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 03/28/2017] [Accepted: 04/04/2017] [Indexed: 01/06/2023]
Abstract
Biological networks, like most engineered networks, are not the product of a singular design but rather are the result of a long process of refinement and optimization. Many large real-world networks are comprised of well-defined and meaningful smaller modules. While engineered networks are designed and refined by humans with particular goals in mind, biological networks are created by the selective pressures of evolution. In this paper, we seek to define aspects of network architecture that are shared among different types of evolved biological networks. First, we developed a new mathematical model, the Stochastic Block Model with Path Selection (SBM-PS) that simulates biological network formation based on the selection of edges that increase clustering. SBM-PS can produce modular networks whose properties resemble those of real networks. Second, we analyzed three real networks of very different types, and showed that all three can be fit well by the SBM-PS model. Third, we showed that modular elements within the three networks correspond to meaningful biological structures. The networks chosen for analysis were a proteomic network composed of all proteins required for mitochondrial function in budding yeast, a mesoscale anatomical network composed of axonal connections among regions of the mouse brain, and the connectome of individual neurons in the nematode C. elegans. We find that the three networks have common architectural features, and each can be divided into subnetworks with characteristic topologies that control specific phenotypic outputs.
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Affiliation(s)
- Bader Al-Anzi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 USA.
| | - Sherif Gerges
- Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142 USA; Analytical and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Noah Olsman
- Control and Dynamical Systems Option, Division of Engineering and Applied Sciences, California Institute of Technology Pasadena, CA 91125 USA
| | - Christopher Ormerod
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 USA ; Department of Mathematics and Statistics, University of Maine, Orono, ME 04469-5752, USA
| | - Georgios Piliouras
- Singapore University of Technology and Design, Engineering Systems and Design (ESD), 8 Somapah Road, 487372 Singapore
| | - John Ormerod
- School of Mathematics and Statistics F07, University of Sydney, NSW 2006, Australia
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 USA.
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18
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Arbeiter F, Abou-Sena A, Averhals J, Böttcher T, Chen Y, Dolensky B, Fischer U, Heinzel A, Heinzel V, Heupel T, Jacquet P, Klein C, Klix A, Kondo K, Konrad J, Lindau R, Möslang A, Muche A, Piecha H, Rolli R, Schlindwein G, Schubert P, Schwab F, Zinn K. Design description and validation results for the IFMIF High Flux Test Module as outcome of the EVEDA phase. Nuclear Materials and Energy 2016. [DOI: 10.1016/j.nme.2016.04.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Carrillo RA, Özkan E, Menon KP, Nagarkar-Jaiswal S, Lee PT, Jeon M, Birnbaum ME, Bellen HJ, Garcia KC, Zinn K. Control of Synaptic Connectivity by a Network of Drosophila IgSF Cell Surface Proteins. Cell 2016; 163:1770-1782. [PMID: 26687361 DOI: 10.1016/j.cell.2015.11.022] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 09/27/2015] [Accepted: 11/10/2015] [Indexed: 12/16/2022]
Abstract
We have defined a network of interacting Drosophila cell surface proteins in which a 21-member IgSF subfamily, the Dprs, binds to a nine-member subfamily, the DIPs. The structural basis of the Dpr-DIP interaction code appears to be dictated by shape complementarity within the Dpr-DIP binding interface. Each of the six dpr and DIP genes examined here is expressed by a unique subset of larval and pupal neurons. In the neuromuscular system, interactions between Dpr11 and DIP-γ affect presynaptic terminal development, trophic factor responses, and neurotransmission. In the visual system, dpr11 is selectively expressed by R7 photoreceptors that use Rh4 opsin (yR7s). Their primary synaptic targets, Dm8 amacrine neurons, express DIP-γ. In dpr11 or DIP-γ mutants, yR7 terminals extend beyond their normal termination zones in layer M6 of the medulla. DIP-γ is also required for Dm8 survival or differentiation. Our findings suggest that Dpr-DIP interactions are important determinants of synaptic connectivity.
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Affiliation(s)
- Robert A Carrillo
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Engin Özkan
- Dept. of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL.,Howard Hughes Medical Institute, Depts. of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA
| | - Kaushiki P Menon
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
| | - Sonal Nagarkar-Jaiswal
- Howard Hughes Medical Institute, Program in Developmental Biology, Dept. of Molecular and Human Genetics, Jan and Dan Duncan Neurological Research Institute at TCH, Baylor College of Medicine, Houston, TX
| | - Pei-Tseng Lee
- Howard Hughes Medical Institute, Program in Developmental Biology, Dept. of Molecular and Human Genetics, Jan and Dan Duncan Neurological Research Institute at TCH, Baylor College of Medicine, Houston, TX
| | - Mili Jeon
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA.,Howard Hughes Medical Institute, Depts. of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA
| | - Michael E Birnbaum
- Howard Hughes Medical Institute, Depts. of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, Program in Developmental Biology, Dept. of Molecular and Human Genetics, Jan and Dan Duncan Neurological Research Institute at TCH, Baylor College of Medicine, Houston, TX
| | - K Christopher Garcia
- Howard Hughes Medical Institute, Depts. of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA
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20
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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: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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21
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Zinn K. Building a ladder to Hershey Heaven. eLife 2016; 5. [PMID: 27023744 PMCID: PMC4821801 DOI: 10.7554/elife.15591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 03/21/2016] [Indexed: 11/13/2022] Open
Abstract
A genome-wide resource looks set to turn an experimental ideal into a reality for the
Drosophila community.
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Affiliation(s)
- Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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22
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Abou-Sena A, Arbeiter F, Baumgaertner S, Boettcher T, Heinzel A, Piecha H, Zinn K. Chemical compatibility of Eurofer steel with sodium-potassium NaK-78 eutectic alloy. Fusion Engineering and Design 2016. [DOI: 10.1016/j.fusengdes.2015.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Ilić M, Messemer G, Zinn K, Meyder R, Kecskes S, Kiss B. Experimental and numerical investigations of heat transfer in the first wall of Helium-Cooled-Pebble-Bed Test Blanket Module—Part 2: Presentation of results. Fusion Engineering and Design 2015. [DOI: 10.1016/j.fusengdes.2014.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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24
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Bower DV, Lee HK, Lansford R, Zinn K, Warburton D, Fraser SE, Jesudason EC. Airway branching has conserved needs for local parasympathetic innervation but not neurotransmission. BMC Biol 2014; 12:92. [PMID: 25385196 PMCID: PMC4255442 DOI: 10.1186/s12915-014-0092-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 10/20/2014] [Indexed: 11/24/2022] Open
Abstract
Background Parasympathetic signaling has been inferred to regulate epithelial branching as well as organ regeneration and tumor development. However, the relative contribution of local nerve contact versus secreted signals remains unclear. Here, we show a conserved (vertebrates to invertebrates) requirement for intact local nerves in airway branching, persisting even when cholinergic neurotransmission is blocked. Results In the vertebrate lung, deleting enhanced green fluorescent protein (eGFP)-labeled intrinsic neurons using a two-photon laser leaves adjacent cells intact, but abolishes branching. Branching is unaffected by similar laser power delivered to the immediately adjacent non-neural mesodermal tissue, by blocking cholinergic receptors or by blocking synaptic transmission with botulinum toxin A. Because adjacent vasculature and epithelial proliferation also contribute to branching in the vertebrate lung, the direct dependence on nerves for airway branching was tested by deleting neurons in Drosophila embryos. A specific deletion of neurons in the Drosophila embryo by driving cell-autonomous RicinA under the pan-neuronal elav enhancer perturbed Drosophila airway development. This system confirmed that even in the absence of a vasculature or epithelial proliferation, airway branching is still disrupted by neural lesioning. Conclusions Together, this shows that airway morphogenesis requires local innervation in vertebrates and invertebrates, yet neurotransmission is dispensable. The need for innervation persists in the fly, wherein adjacent vasculature and epithelial proliferation are absent. Our novel, targeted laser ablation technique permitted the local function of parasympathetic innervation to be distinguished from neurotransmission. Electronic supplementary material The online version of this article (doi:10.1186/s12915-014-0092-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Danielle V Bower
- Division of Biological Sciences, California Institute of Technology, Pasadena, USA. .,The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, USA. .,Biological Imaging Center, California Institute of Technology, 1200 E. California Blvd, MC 139-74, Pasadena, CA, 91125, USA.
| | - Hyung-Kook Lee
- Division of Biological Sciences, California Institute of Technology, Pasadena, USA.
| | - Rusty Lansford
- The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, USA.
| | - Kai Zinn
- Division of Biological Sciences, California Institute of Technology, Pasadena, USA.
| | - David Warburton
- The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, USA.
| | - Scott E Fraser
- Division of Biological Sciences, California Institute of Technology, Pasadena, USA. .,Biological Sciences and Biomedical Engineering, University of Southern California, Los Angeles, USA. .,Biological Imaging Center, California Institute of Technology, 1200 E. California Blvd, MC 139-74, Pasadena, CA, 91125, USA.
| | - Edwin C Jesudason
- Division of Biological Sciences, California Institute of Technology, Pasadena, USA. .,The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, USA. .,Division of Child Health, University of Liverpool, Liverpool, UK. .,Biological Imaging Center, California Institute of Technology, 1200 E. California Blvd, MC 139-74, Pasadena, CA, 91125, USA.
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Szul T, Burgess J, Jeon M, Zinn K, Marques G, Brill JA, Sztul E. The Garz Sec7 domain guanine nucleotide exchange factor for Arf regulates salivary gland development in Drosophila. Cell Logist 2014; 1:69-76. [PMID: 21686256 DOI: 10.4161/cl.1.2.15512] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/11/2011] [Accepted: 03/17/2011] [Indexed: 12/22/2022]
Abstract
Surface delivery of proteins involved in cell-cell and cell-matrix interactions in cultured mammalian cells requires the GBF1 guanine nucleotide exchange factor. However, the role of GBF1 in delivery of adhesion proteins during organogenesis in intact animals has not been characterized. Here, we report the function of the fly GBF1 homolog, Gartenzwerg (Garz) in the development of the salivary gland in Drosophila melanogaster. We used the GAL4/UAS system to selectively deplete Garz from salivary gland cells. We show that depletion of Garz disrupts the secretory pathway as evidenced by the collapse of Golgi-localized Lava lamp (Lva) and the TGN-localized γ subunit of the clathrin-adaptor protein complex (AP-1). Additionally, Garz depletion inhibits trafficking of cell-cell adhesion proteins cadherin (DE-cad) and Flamingo to the cell surface. Disregulation of trafficking correlates with mistargeting of the tumor suppressor protein Discs large involved in epithelial polarity determination. Garz-depleted salivary cells are smaller and lack well-defined plasma membrane domains. Garz depletion also inhibits normal elongation and positioning of epithelial cells, resulting in a disorganized salivary gland that lacks a well defined luminal duct. Our findings suggest that Garz is essential for establishment of epithelial structures and demonstrate an absolute requirement for Garz during Drosophila development.
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Affiliation(s)
- Tomasz Szul
- Department of Cell Biology; University of Alabama at Birmingham; Birmingham, AL USA
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Jeon M, Zinn K. R3 receptor tyrosine phosphatases: conserved regulators of receptor tyrosine kinase signaling and tubular organ development. Semin Cell Dev Biol 2014; 37:119-26. [PMID: 25242281 DOI: 10.1016/j.semcdb.2014.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 09/04/2014] [Indexed: 12/25/2022]
Abstract
R3 receptor tyrosine phosphatases (RPTPs) are characterized by extracellular domains composed solely of long chains of fibronectin type III repeats, and by the presence of a single phosphatase domain. There are five proteins in mammals with this structure, two in Drosophila and one in Caenorhabditis elegans. R3 RPTPs are selective regulators of receptor tyrosine kinase (RTK) signaling, and a number of different RTKs have been shown to be direct targets for their phosphatase activities. Genetic studies in both invertebrate model systems and in mammals have shown that R3 RPTPs are essential for tubular organ development. They also have important functions during nervous system development. R3 RPTPs are likely to be tumor suppressors in a number of types of cancer.
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Affiliation(s)
- Mili Jeon
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States; Department of Molecular and Cellular Physiology and Structural Biology, Howard Hughes Medical Institute, Stanford School of Medicine, Palo Alto, CA 94305, United States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
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Lee HKP, Cording A, Vielmetter J, Zinn K. Interactions between a receptor tyrosine phosphatase and a cell surface ligand regulate axon guidance and glial-neuronal communication. Neuron 2013; 78:813-26. [PMID: 23764287 DOI: 10.1016/j.neuron.2013.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2013] [Indexed: 12/31/2022]
Abstract
We developed a screening method for orphan receptor ligands, in which cell-surface proteins are expressed in Drosophila embryos from GAL4-dependent insertion lines and ligand candidates identified by the presence of ectopic staining with receptor fusion proteins. Stranded at second (Sas) binds to the receptor tyrosine phosphatase Ptp10D in embryos and in vitro. Sas and Ptp10D can interact in trans when expressed in cultured cells. Interactions between Sas and Ptp10D on longitudinal axons are required to prevent them from abnormally crossing the midline. Sas is expressed on both neurons and glia, whereas Ptp10D is restricted to CNS axons. We conducted epistasis experiments by overexpressing Sas in glia and examining how the resulting phenotypes are changed by removal of Ptp10D from neurons. We find that neuronal Ptp10D restrains signaling by overexpressed glial Sas, which would otherwise produce strong glial and axonal phenotypes.
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Affiliation(s)
- Hyung-Kook Peter Lee
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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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: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Menon KP, Carrillo RA, Zinn K. Development and plasticity of the Drosophila larval neuromuscular junction. Wiley Interdiscip Rev Dev Biol 2013; 2:647-70. [PMID: 24014452 DOI: 10.1002/wdev.108] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Drosophila larval neuromuscular system is relatively simple, containing only 32 motor neurons in each abdominal hemisegment, and its neuromuscular junctions (NMJs) have been studied extensively. NMJ synapses exhibit developmental and functional plasticity while displaying stereotyped connectivity. Drosophila Type I NMJ synapses are glutamatergic, while the vertebrate NMJ uses acetylcholine as its primary neurotransmitter. The larval NMJ synapses use ionotropic glutamate receptors (GluRs) that are homologous to AMPA-type GluRs in the mammalian brain, and they have postsynaptic scaffolds that resemble those found in mammalian postsynaptic densities. These features make the Drosophila neuromuscular system an excellent genetic model for the study of excitatory synapses in the mammalian central nervous system. The first section of the review presents an overview of NMJ development. The second section describes genes that regulate NMJ development, including: (1) genes that positively and negatively regulate growth of the NMJ, (2) genes required for maintenance of NMJ bouton structure, (3) genes that modulate neuronal activity and alter NMJ growth, (4) genes involved in transsynaptic signaling at the NMJ. The third section describes genes that regulate acute plasticity, focusing on translational regulatory mechanisms. As this review is intended for a developmental biology audience, it does not cover NMJ electrophysiology in detail, and does not review genes for which mutations produce only electrophysiological but no structural phenotypes.
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Affiliation(s)
- Kaushiki P Menon
- Broad Center, Division of Biology, California Institute of Technology, Pasadena, CA, USA
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Jeon M, Scott MP, Zinn K. Interactions between Type III receptor tyrosine phosphatases and growth factor receptor tyrosine kinases regulate tracheal tube formation in Drosophila. Biol Open 2012; 1:548-58. [PMID: 23213447 PMCID: PMC3509443 DOI: 10.1242/bio.2012471] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The respiratory (tracheal) system of the Drosophila melanogaster larva is an intricate branched network of air-filled tubes. Its developmental logic is similar in some ways to that of the vertebrate vascular system. We previously described a unique embryonic tracheal tubulogenesis phenotype caused by loss of both of the Type III receptor tyrosine phosphatases (RPTPs), Ptp4E and Ptp10D. In Ptp4E Ptp10D double mutants, the linear tubes in unicellular and terminal tracheal branches are converted into bubble-like cysts that incorporate apical cell surface markers. This tube geometry phenotype is modulated by changes in the activity or expression of the epidermal growth factor receptor (Egfr) tyrosine kinase (TK). Ptp10D physically interacts with Egfr. Here we demonstrate that the Ptp4E Ptp10D phenotype is the consequence of the loss of negative regulation by the RPTPs of three growth factor receptor TKs: Egfr, Breathless and Pvr. Reducing the activity of any of the three kinases by tracheal expression of dominant-negative mutants suppresses cyst formation. By competing dominant-negative and constitutively active kinase mutants against each other, we show that the three RTKs have partially interchangeable activities, so that increasing the activity of one kinase can compensate for the effects of reducing the activity of another. This implies that SH2-domain downstream effectors that are required for the phenotype are likely to be able to interact with phosphotyrosine sites on all three receptor TKs. We also show that the phenotype involves increases in signaling through the MAP kinase and Rho GTPase pathways.
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Affiliation(s)
- Mili Jeon
- Division of Biology 114-96, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125 , USA ; Departments of Developmental Biology, Genetics, and Bioengineering, Howard Hughes Medical Institute, 318 Campus Drive, Stanford University School of Medicine , Palo Alto, CA 94305 , USA
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Kurusu M, Katsuki T, Zinn K, Suzuki E. Developmental changes in expression, subcellular distribution, and function of Drosophila N-cadherin, guided by a cell-intrinsic program during neuronal differentiation. Dev Biol 2012; 366:204-17. [PMID: 22542600 DOI: 10.1016/j.ydbio.2012.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 10/28/2022]
Abstract
Cell adhesion molecules (CAMs) perform numerous functions during neural development. An individual CAM can play different roles during each stage of neuronal differentiation; however, little is known about how such functional switching is accomplished. Here we show that Drosophila N-cadherin (CadN) is required at multiple developmental stages within the same neuronal population and that its sub-cellular expression pattern changes between the different stages. During development of mushroom body neurons and motoneurons, CadN is expressed at high levels on growing axons, whereas expression becomes downregulated and restricted to synaptic sites in mature neurons. Phenotypic analysis of CadN mutants reveals that developing axons require CadN for axon guidance and fasciculation, whereas mature neurons for terminal growth and receptor clustering. Furthermore, we demonstrate that CadN downregulation can be achieved in cultured neurons without synaptic contact with other cells. Neuronal silencing experiments using Kir(2.1) indicate that neuronal excitability is also dispensable for CadN downregulation in vivo. Interestingly, downregulation of CadN can be prematurely induced by ectopic expression of a nonselective cation channel, dTRPA1, in developing neurons. Together, we suggest that switching of CadN expression during neuronal differentiation involves regulated cation influx within neurons.
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Affiliation(s)
- Mitsuhiko Kurusu
- Structural Biology Center, National Institute of Genetics and Department of Genetics, The Graduate University for Advanced Studies, Mishima 411-8540, Japan.
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Affiliation(s)
- Bader Al-Anzi
- Division of Biology, California Institute of Technology Pasadena, CA, USA
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Kim K, Wang M, Barnes M, O'Malley J, You Z, Preuss M, Siegal G, Zinn K, Curiel D, Alvarez R. A phase I clinical trial of a novel infectivity-enhanced suicide gene adenovirus with gene transfer imaging capacity in patients with recurrent gynecologic cancer. Gynecol Oncol 2011. [DOI: 10.1016/j.ygyno.2010.12.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Al-Anzi B, Zinn K. Colorimetric measurement of triglycerides cannot provide an accurate measure of stored fat content in Drosophila. PLoS One 2010; 5:e12353. [PMID: 20808765 PMCID: PMC2927426 DOI: 10.1371/journal.pone.0012353] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 07/18/2010] [Indexed: 11/18/2022] Open
Abstract
Drosophila melanogaster has recently emerged as a useful model system in which to study the genetic basis of regulation of fat storage. One of the most frequently used methods for evaluating the levels of stored fat (triglycerides) in flies is a coupled colorimetric assay available as a kit from several manufacturers. This is an aqueous-based enzymatic assay that is normally used for measurement of mammalian serum triglycerides, which are present in soluble lipoprotein complexes. In this short communication, we show that coupled colorimetric assay kits cannot accurately measure stored triglycerides in Drosophila. First, they fail to give accurate readings when tested on insoluble triglyceride mixtures with compositions like that of stored fat, or on fat extracted from flies with organic solvents. This is probably due to an inability of the lipase used in the kits to efficiently cleave off the glycerol head group from fat molecules in insoluble samples. Second, the measured final products of the kits are quinoneimines, which absorb visible light in the same wavelength range as Drosophila eye pigments. Thus, when extracts from crushed flies are assayed, much of the measured signal is actually due to eye pigments. Finally, the lipoprotein lipases used in colorimetric assays also cleave non-fat glycerides. The glycerol backbones liberated from all classes of glycerides are measured through the remaining reactions in the assay. As a consequence, when these assay kits are used to evaluate tissue extracts, the observed signal actually represents the amount of free glycerols together with all types of glycerides. For these reasons, findings obtained through use of coupled colorimetric assays on Drosophila samples must be interpreted with caution. We also show here that using thin-layer chromatography to measure stored triglycerides in flies eliminates all of these problems.
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Affiliation(s)
- Bader Al-Anzi
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- * E-mail: (KZ); (BA-A)
| | - Kai Zinn
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- * E-mail: (KZ); (BA-A)
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35
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Wright AP, Fox AN, Johnson KG, Zinn K. Systematic screening of Drosophila deficiency mutations for embryonic phenotypes and orphan receptor ligands. PLoS One 2010; 5:e12288. [PMID: 20808815 PMCID: PMC2924397 DOI: 10.1371/journal.pone.0012288] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/21/2010] [Indexed: 11/18/2022] Open
Abstract
This paper defines a collection of Drosophila deletion mutations (deficiencies) that can be systematically screened for embryonic phenotypes, orphan receptor ligands, and genes affecting protein localization. It reports the results of deficiency screens we have conducted that have revealed new axon guidance phenotypes in the central nervous system and neuromuscular system and permitted a quantitative assessment of the number of potential genes involved in regulating guidance of specific motor axon branches. Deficiency “kits” that cover the genome with a minimum number of lines have been established to facilitate gene mapping. These kits cannot be systematically analyzed for phenotypes, however, since embryos homozygous for many deficiencies in these kits fail to develop due to the loss of key gene products encoded within the deficiency. To create new kits that can be screened for phenotype, we have examined the development of the nervous system in embryos homozygous for more than 700 distinct deficiency mutations. A kit of ∼400 deficiency lines for which homozygotes have a recognizable nervous system and intact body walls encompasses >80% of the genome. Here we show examples of screens of this kit for orphan receptor ligands and neuronal antigen expression. It can also be used to find genes involved in expression, patterning, and subcellular localization of any protein that can be visualized by antibody staining. A subset kit of 233 deficiency lines, for which homozygotes develop relatively normally to late stage 16, covers ∼50% of the genome. We have screened it for axon guidance phenotypes, and we present examples of new phenotypes we have identified. The subset kit can be used to screen for phenotypes affecting all embryonic organs. In the future, these deficiency kits will allow Drosophila researchers to rapidly and efficiently execute genome-wide anatomical screens that require examination of individual embryos at high magnification.
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Affiliation(s)
- Ashley P. Wright
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - A. Nicole Fox
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Karl G. Johnson
- Department of Biology and Program in Neuroscience, Pomona College, Claremont, California, United States of America
| | - Kai Zinn
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- * E-mail:
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36
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Al-Anzi B, Armand E, Nagamei P, Olszewski M, Sapin V, Waters C, Zinn K, Wyman RJ, Benzer S. The leucokinin pathway and its neurons regulate meal size in Drosophila. Curr Biol 2010; 20:969-78. [PMID: 20493701 DOI: 10.1016/j.cub.2010.04.039] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/12/2010] [Accepted: 04/19/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Total food intake is a function of meal size and meal frequency, and adjustments to these parameters allow animals to maintain a stable energy balance in changing environmental conditions. The physiological mechanisms that regulate meal size have been studied in blowflies but have not been previously examined in Drosophila. RESULTS Here we show that mutations in the leucokinin neuropeptide (leuc) and leucokinin receptor (lkr) genes cause phenotypes in which Drosophila adults have an increase in meal size and a compensatory reduction in meal frequency. Because mutant flies take larger but fewer meals, their caloric intake is the same as that of wild-type flies. The expression patterns of the leuc and lkr genes identify small groups of brain neurons that regulate this behavior. Leuc-containing presynaptic terminals are found close to Lkr neurons in the brain and ventral ganglia, suggesting that they deliver Leuc peptide to these neurons. Lkr neurons innervate the foregut. Flies in which Leuc or Lkr neurons are ablated have defects identical to those of leucokinin pathway mutants. CONCLUSIONS Our data suggest that the increase in meal size in leuc and lkr mutants is due to a meal termination defect, perhaps arising from impaired communication of gut distension signals to the brain. Leucokinin and the leucokinin receptor are homologous to vertebrate tachykinin and its receptor, and injection of tachykinins reduces food consumption. Our results suggest that the roles of the tachykinin system in regulating food intake might be evolutionarily conserved between insects and vertebrates.
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Affiliation(s)
- Bader Al-Anzi
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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37
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Lee HKP, Wright AP, Zinn K. Live dissection of Drosophila embryos: streamlined methods for screening mutant collections by antibody staining. J Vis Exp 2009:1647. [PMID: 20040910 DOI: 10.3791/1647] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Drosophila embryos between stages 14 and 17 of embryonic development can be readily dissected to generate "fillet" preparations. In these preparations, the central nervous system runs down the middle, and is flanked by the body walls. Many different phenotypes have been examined using such preparations. In most cases, the fillets were generated by dissection of antibody-stained fixed whole-mount embryos. These "fixed dissections" have some disadvantages, however. They are time-consuming to execute, and it is difficult to sort mutant (GFP-negative) embryos from stocks in which mutations are maintained over GFP balancer chromosomes. Since 2002, our group has been conducting deficiency and ectopic expression screens to identify ligands for orphan receptors. In order to do this, we developed streamlined protocols for live embryo dissection and antibody staining of collections containing hundreds of balanced lines. We have concluded that it is considerably more efficient to examine phenotypes in large collections of stocks by live dissection than by fixed dissection. Using the protocol described here, a single trained individual can screen up to 10 lines per day for phenotypes, examining 4-7 mutant embryos from each line under a compound microscope. This allows the identification of mutations conferring subtle, low-penetrance phenotypes, since up to 70 hemisegments per line are scored at high magnification with a 40X water-immersion lens.
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Hong W, Zhu H, Potter CJ, Barsh G, Kurusu M, Zinn K, Luo L. Leucine-rich repeat transmembrane proteins instruct discrete dendrite targeting in an olfactory map. Nat Neurosci 2009; 12:1542-50. [PMID: 19915565 PMCID: PMC2826190 DOI: 10.1038/nn.2442] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/01/2009] [Indexed: 11/09/2022]
Abstract
Olfactory systems utilize discrete neural pathways to process and integrate odorant information. In Drosophila, axons of first-order olfactory receptor neurons (ORNs) and dendrites of second-order projection neurons (PNs) form class-specific synaptic connections at approximately 50 glomeruli. The mechanisms underlying PN dendrite targeting to distinct glomeruli in a three-dimensional discrete neural map are unclear. We found that the leucine-rich repeat (LRR) transmembrane protein Capricious (Caps) was differentially expressed in different classes of PNs. Loss-of-function and gain-of-function studies indicated that Caps instructs the segregation of Caps-positive and Caps-negative PN dendrites to discrete glomerular targets. Moreover, Caps-mediated PN dendrite targeting was independent of presynaptic ORNs and did not involve homophilic interactions. The closely related protein Tartan was partially redundant with Caps. These LRR proteins are probably part of a combinatorial cell-surface code that instructs discrete olfactory map formation.
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Affiliation(s)
- Weizhe Hong
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, California, USA
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39
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Wright AP, Zinn K. Guidance receptors find their places in the axonal order. Neuron 2009; 64:150-2. [PMID: 19874780 DOI: 10.1016/j.neuron.2009.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this issue of Neuron, Katsuki and colleagues show that cell-autonomous mechanisms divide Drosophila axons into proximal and distal compartments. Axon guidance receptors selectively localize to one compartment. A diffusion barrier exists near the compartment boundary, suggesting that it may have properties like those of the axon initial segment in mammalian neurons.
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Affiliation(s)
- Ashley P Wright
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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40
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Abstract
The formation of epithelial tubes with defined shapes and sizes is essential for organ development. We describe a unique tracheal tubulogenesis phenotype caused by loss of both Drosophila type III receptor tyrosine phosphatases (RPTPs), Ptp4E and Ptp10D. Ptp4E is the only widely expressed Drosophila RPTP, and is the last of the six fly RPTPs to be genetically characterized. We recently isolated mutations in Ptp4E, and discovered that, although Ptp4E null mutants have no detectable phenotypes, double mutants lacking both Ptp4E and Ptp10D display synthetic lethality at hatching owing to respiratory failure. In these double mutants, unicellular and terminal tracheal branches develop large bubble-like cysts that selectively incorporate apical cell surface markers. Cysts in unicellular branches are enlargements of the lumen that are sealed by adherens junctions, whereas cysts in terminal branches are cytoplasmic vacuoles. Cyst size and number are increased by tracheal expression of activated Egfr tyrosine kinase, and decreased by reducing Egfr levels. Ptp10D forms a complex with Egfr in transfected cells. Downregulation of Egfr signaling by the RPTPs is required for the construction of tubular lumens, whether extracellular or intracellular, by cells that undergo remodeling during branch morphogenesis. The Ptp4E Ptp10D phenotype represents the first evidence of an essential role for RPTPs in epithelial organ development. These findings might be relevant to organ development and disease in mammals, because PTPRJ (DEP-1), an ortholog of Ptp4E/Ptp10D, interacts with the hepatocyte growth factor receptor tyrosine kinase. PTPRJ corresponds to the murine Scc1 (suppressor of colon cancer) gene.
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Affiliation(s)
- Mili Jeon
- Broad Center, Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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41
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Abstract
In this issue of Genes & Development, Siebert and colleagues (pp. 1052-1062) define a ligand-receptor system that controls motor axon guidance and target recognition in the Drosophila embryo. The beaten path (beat) and sidestep (side) genes were known to be important regulators of motor axon guidance. Siebert and colleagues now show that Beat and Side are cell surface proteins that physically interact with each other, and that Beat-expressing motor axon growth cones reach their targets via recognition of Side-expressing pathways.
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Affiliation(s)
- Kai Zinn
- Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
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Withrow KP, Newman JR, Skipper JB, Gleysteen JP, Magnuson JS, Zinn K, Rosenthal EL. Assessment of bevacizumab conjugated to Cy5.5 for detection of head and neck cancer xenografts. Technol Cancer Res Treat 2008; 7:61-6. [PMID: 18198926 DOI: 10.1177/153303460800700108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Optical fluorescent technology has the potential to deliver real time imaging of cancer into the operating room and the clinic. To determine the efficacy of fluorescently labeled anti-vascular endothelial growth factor (VEGF) antibody to be used as a cancer specific optical contrast agent to guide surgical resections, we evaluated the sensitivity and specificity of this agent to detect microscopic residual disease in a preclinical model of head and neck squamous cell carcinoma (HNSCC). Using a flank murine model, mice were xenografted with SCC-1 tumor cells and injected with anti-VEGF antibody (bevacizumab) conjugated to an optically active fluorophore (Cy5.5). Tumors underwent sub-total resections and were assessed for the presence of residual disease by fluorescent stereomicroscopy. Expected positive and negative biopsies were taken according to the presence or absence of fluorescence, respectively. Histology was used to confirm the presence or absence of disease. Biopsies taken from areas of fluorescence within the wound bed (n=18) were found to be histologically malignant in all but one biopsy. Samples taken from a non-fluorescing tumor bed (n=15) were found to be histologically benign in 11 of 15. These findings correlated with a sensitivity and specificity of 80.9% and 91.7%, respectively. This data supports previous data presented by this group and supports further investigation of fluorescently labeled anti-tumor antibodies to detect disease in the surgical setting.
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Affiliation(s)
- K P Withrow
- Department of Surgery, Division of Otolaryngology - Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
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Kurusu M, Zinn K. Receptor tyrosine phosphatases regulate birth order-dependent axonal fasciculation and midline repulsion during development of the Drosophila mushroom body. Mol Cell Neurosci 2008; 38:53-65. [PMID: 18356078 DOI: 10.1016/j.mcn.2008.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 01/18/2008] [Accepted: 01/25/2008] [Indexed: 01/05/2023] Open
Abstract
Receptor tyrosine phosphatases (RPTPs) are required for axon guidance during embryonic development in Drosophila. Here we examine the roles of four RPTPs during development of the larval mushroom body (MB). MB neurons extend axons into parallel tracts known as the peduncle and lobes. The temporal order of neuronal birth is reflected in the organization of axons within these tracts. Axons of the youngest neurons, known as core fibers, extend within a single bundle at the center, while those of older neurons fill the outer layers. RPTPs are selectively expressed on the core fibers of the MB. Ptp10D and Ptp69D regulate segregation of the young axons into a single core bundle. Ptp69D signaling is required for axonal extension beyond the peduncle. Lar and Ptp69D are necessary for the axonal branching decisions that create the lobes. Avoidance of the brain midline by extending medial lobe axons involves signaling through Lar.
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Affiliation(s)
- Mitsuhiko Kurusu
- Broad Center, Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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44
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Jeon M, Nguyen H, Bahri S, Zinn K. Redundancy and compensation in axon guidance: genetic analysis of the Drosophila Ptp10D/Ptp4E receptor tyrosine phosphatase subfamily. Neural Dev 2008; 3:3. [PMID: 18237413 PMCID: PMC2270841 DOI: 10.1186/1749-8104-3-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 01/31/2008] [Indexed: 12/27/2022] Open
Abstract
Background Drosophila has six receptor protein tyrosine phosphatases (RPTPs), five of which are expressed primarily in neurons. Mutations in all five affect axon guidance, either alone or in combination. Highly penetrant central nervous system (CNS) and motor axon guidance alterations are usually observed only when specific combinations of two or more RPTPs are removed. Here, we examine the sixth RPTP, Ptp4E, which is broadly expressed. Results Ptp4E and Ptp10D are closely related type III RPTPs. Non-drosophilid insect species have only one type III RPTP, which is closest to Ptp10D. We found that Ptp4E mutants are viable and fertile. We then examined Ptp4E Ptp10D double mutants. These die before the larval stage, and have a mild CNS phenotype in which the outer longitudinal 1D4 bundle is frayed. Ptp10D Ptp69D double mutants have a strong CNS phenotype in which 1D4 axons abnormally cross the midline and the outer and middle longitudinal bundles are fused to the inner bundle. To examine if Ptp4E also exhibits synthetic phenotypes in combination with Ptp69D, we made Ptp4E Ptp69D double mutants and Ptp4E Ptp10D Ptp69D triple mutants. No phenotype was observed in the double mutant. The triple mutant phenotype differs from the Ptp10D Ptp69D phenotype in two ways. First, the longitudinal tracts appear more normal than in the double mutant; two or three bundles are observed, although they are disorganized and fused. Second, axons labelled by the SemaIIB-τMyc marker often cross in the wrong commissure. We also examined motor axon guidance, and found that no phenotypes are observed in any Ptp4E double mutant combination. However, triple mutants in which Ptp4E Ptp10D was combined with Ptp69D or Ptp52F exhibited stronger phenotypes than the corresponding Ptp10D double mutants. Conclusion Type III RPTPs are required for viability in Drosophila, since Ptp4E Ptp10D double mutants die before the larval stage. Unlike Ptp10D, Ptp4E appears to be a relatively minor player in the control of axon guidance. Strong phenotypes are only observed in triple mutants in which both type III RPTPs are eliminated together with Ptp69D or Ptp52F. Our results allow us to construct a complete genetic interaction matrix for all six of the RPTPs.
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Affiliation(s)
- Mili Jeon
- Broad Center, Division of Biology, California Institute of Technology Pasadena, California 91125, USA.
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Kruessmann R, Messemer G, Norajitra P, Weggen J, Zinn K. Validation of computational fluid dynamics (CFD) tools for the development of a helium-cooled divertor. Fusion Engineering and Design 2007. [DOI: 10.1016/j.fusengdes.2007.03.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ratnaparkhi A, Zinn K. The secreted cell signal Folded Gastrulation regulates glial morphogenesis and axon guidance in Drosophila. Dev Biol 2007; 308:158-68. [PMID: 17560973 PMCID: PMC2041958 DOI: 10.1016/j.ydbio.2007.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 05/11/2007] [Accepted: 05/16/2007] [Indexed: 11/29/2022]
Abstract
During gastrulation in Drosophila, ventral cells change shape, undergoing synchronous apical constriction, to create the ventral furrow (VF). This process is affected in mutant embryos lacking zygotic function of the folded gastrulation (fog) gene, which encodes a putative secreted protein. Fog is an essential autocrine signal that induces cytoskeletal changes in invaginating VF cells. Here we show that Fog is also required for nervous system development. Fog is expressed by longitudinal glia in the central nervous system (CNS), and reducing its expression in glia causes defects in process extension and axon ensheathment. Glial Fog overexpression produces a disorganized glial lattice. Fog has a distinct set of functions in CNS neurons. Our data show that reduction or overexpression of Fog in these neurons produces axon guidance phenotypes. Interestingly, these phenotypes closely resemble those seen in embryos with altered expression of the receptor tyrosine phosphatase PTP52F. We conducted epistasis experiments to define the genetic relationships between Fog and PTP52F, and the results suggest that PTP52F is a downstream component of the Fog signaling pathway in CNS neurons. We also found that Ptp52F mutants have early VF phenotypes like those seen in fog mutants.
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Affiliation(s)
| | - Kai Zinn
- Corresponding author (, 626-395-8352, 626-568-0631 (fax))
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Fox AN, Zinn K. The heparan sulfate proteoglycan syndecan is an in vivo ligand for the Drosophila LAR receptor tyrosine phosphatase. Curr Biol 2006; 15:1701-11. [PMID: 16213816 DOI: 10.1016/j.cub.2005.08.035] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 08/04/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Receptor tyrosine phosphatases (RPTPs) are essential for axon guidance and synaptogenesis in Drosophila. Each guidance decision made by embryonic motor axons during outgrowth to their muscle targets requires a specific subset of the five neural RPTPs. The logic underlying these requirements, however, is still unclear, partially because the ligands recognized by RPTPs at growth cone choice points have not been identified. RPTPs in general are still "orphan receptors" because, while they have been found to interact in vitro with many different proteins, their in vivo ligands are unknown. RESULTS Here we use a new type of deficiency screen to identify the transmembrane heparan sulfate proteoglycan Syndecan (Sdc) as a ligand for the neuronal RPTP LAR. LAR interacts with the glycosaminoglycan chains of Syndecan in vitro with nanomolar affinity. Genetic interaction studies using Sdc and Lar LOF mutations demonstrate that Sdc contributes to LAR's function in motor axon guidance. We also show that overexpression of Sdc on muscles generates the same phenotype as overexpression of LAR in neurons and that genetic removal of LAR suppresses the phenotype produced by ectopic muscle Sdc. Finally, we show that there is at least one additional, nonproteoglycan, ligand for LAR encoded in the genome. CONCLUSIONS Taken together, our results demonstrate that Sdc on muscles can interact with neuronal LAR in vivo and that binding to Sdc increases LAR's signaling efficacy. Thus, Sdc is a ligand that can act in trans to positively regulate signal transduction through LAR within neuronal growth cones.
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Affiliation(s)
- A Nicole Fox
- Broad Center, Division of Biology, California Institute of Technology, Pasadena 91125, USA
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Menon KP, Sanyal S, Habara Y, Sanchez R, Wharton RP, Ramaswami M, Zinn K. The translational repressor Pumilio regulates presynaptic morphology and controls postsynaptic accumulation of translation factor eIF-4E. Neuron 2005; 44:663-76. [PMID: 15541314 DOI: 10.1016/j.neuron.2004.10.028] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Revised: 06/26/2004] [Accepted: 10/06/2004] [Indexed: 11/21/2022]
Abstract
Translational repression by Drosophila Pumilio (Pum) protein controls posterior patterning during embryonic development. Here, we show that Pum is an important mediator of synaptic growth and plasticity at the neuromuscular junction (NMJ). Pum is localized to the postsynaptic side of the NMJ in third instar larvae and is also expressed in larval neurons. Neuronal Pum regulates synaptic growth. In its absence, NMJ boutons are larger and fewer in number, while Pum overexpression increases bouton number and decreases bouton size. Postsynaptic Pum negatively regulates expression of the translation factor eIF-4E at the NMJ, and Pum binds selectively to the 3'UTR of eIF-4E mRNA. The GluRIIa glutamate receptor is upregulated in pum mutants. These results, together with genetic epistasis studies, suggest that postsynaptic Pum modulates synaptic function via direct control of eIF-4E expression.
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Affiliation(s)
- Kaushiki P Menon
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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Abstract
Two papers in the current issues of Neuron (Gallegos and Bargmann) and Cell (Emoto et al.) identify a conserved kinase, SAX-1/Trc, and a large protein required for Trc activity, SAX-2/Fry, as essential elements in the control of dendritic branching and tiling in Drosophila and C. elegans. The tiling and ectopic branching phenotypes of trc mutants appear to be independently generated. Thus, this kinase is the first signaling protein to be associated specifically with tiling.
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Affiliation(s)
- Kai Zinn
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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Sherwood NT, Sun Q, Xue M, Zhang B, Zinn K. Drosophila spastin regulates synaptic microtubule networks and is required for normal motor function. PLoS Biol 2004; 2:e429. [PMID: 15562320 PMCID: PMC532392 DOI: 10.1371/journal.pbio.0020429] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Accepted: 10/12/2004] [Indexed: 11/19/2022] Open
Abstract
The most common form of human autosomal dominant hereditary spastic paraplegia (AD-HSP) is caused by mutations in the SPG4 (spastin) gene, which encodes an AAA ATPase closely related in sequence to the microtubule-severing protein Katanin. Patients with AD-HSP exhibit degeneration of the distal regions of the longest axons in the spinal cord. Loss-of-function mutations in the Drosophila spastin gene produce larval neuromuscular junction (NMJ) phenotypes. NMJ synaptic boutons in spastin mutants are more numerous and more clustered than in wild-type, and transmitter release is impaired. spastin-null adult flies have severe movement defects. They do not fly or jump, they climb poorly, and they have short lifespans. spastin hypomorphs have weaker behavioral phenotypes. Overexpression of Spastin erases the muscle microtubule network. This gain-of-function phenotype is consistent with the hypothesis that Spastin has microtubule-severing activity, and implies that spastin loss-of-function mutants should have an increased number of microtubules. Surprisingly, however, we observed the opposite phenotype: in spastin-null mutants, there are fewer microtubule bundles within the NMJ, especially in its distal boutons. The Drosophila NMJ is a glutamatergic synapse that resembles excitatory synapses in the mammalian spinal cord, so the reduction of organized presynaptic microtubules that we observe in spastin mutants may be relevant to an understanding of human Spastin's role in maintenance of axon terminals in the spinal cord.
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Affiliation(s)
- Nina Tang Sherwood
- 1Broad Center, Division of Biology, California Institute of TechnologyPasadena, CaliforniaUnited States of America
| | - Qi Sun
- 1Broad Center, Division of Biology, California Institute of TechnologyPasadena, CaliforniaUnited States of America
| | - Mingshan Xue
- 2Section of Neurobiology, University of TexasAustin, TexasUnited States of America
| | - Bing Zhang
- 2Section of Neurobiology, University of TexasAustin, TexasUnited States of America
| | - Kai Zinn
- 1Broad Center, Division of Biology, California Institute of TechnologyPasadena, CaliforniaUnited States of America
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