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Dlg Is Required for Short-Term Memory and Interacts with NMDAR in the Drosophila Brain. Int J Mol Sci 2022; 23:ijms23169187. [PMID: 36012453 PMCID: PMC9409279 DOI: 10.3390/ijms23169187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/10/2022] [Accepted: 08/14/2022] [Indexed: 11/17/2022] Open
Abstract
The vertebrates’ scaffold proteins of the Dlg-MAGUK family are involved in the recruitment, clustering, and anchoring of glutamate receptors to the postsynaptic density, particularly the NMDA subtype glutamate-receptors (NRs), necessary for long-term memory and LTP. In Drosophila, the only gene of the subfamily generates two main products, dlgA, broadly expressed, and dlgS97, restricted to the nervous system. In the Drosophila brain, NRs are expressed in the adult brain and are involved in memory, however, the role of Dlg in these processes and its relationship with NRs has been scarcely explored. Here, we show that the dlg mutants display defects in short-term memory in the olfactory associative-learning paradigm. These defects are dependent on the presence of DlgS97 in the Mushroom Body (MB) synapses. Moreover, Dlg is immunoprecipitated with NRs in the adult brain. Dlg is also expressed in the larval neuromuscular junction (NMJ) pre and post-synaptically and is important for development and synaptic function, however, NR is absent in this synapse. Despite that, we found changes in the short-term plasticity paradigms in dlg mutant larval NMJ. Together our results show that larval NMJ and the adult brain relies on Dlg for short-term memory/plasticity, but the mechanisms differ in the two types of synapses.
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2
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Keane S, Martinsson T, Kogner P, Ejeskär K. The loss of DLG2 isoform 7/8, but not isoform 2, is critical in advanced staged neuroblastoma. Cancer Cell Int 2021; 21:170. [PMID: 33726762 PMCID: PMC7962242 DOI: 10.1186/s12935-021-01851-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 02/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neuroblastoma is a childhood neural crest tumor showing large clinical and genetic heterogeneity, one form displaying 11q-deletion is very aggressive. It has been shown that 11q-deletion results in decreased expression of DLG2, a gene residing in the deleted region. DLG2 has a number of different isoforms with the main difference is the presence or absence of a L27 domain. The L27 domain containing DLG proteins can form complexes with CASK/MPP and LIN7 protein family members, which will control cell polarity and signaling. METHODS We evaluated the DLG gene family and the LIN7 gene family for their expression in differently INSS staged neuroblastoma from publically available data and primary tumors, we included two distinct DLG1 and DLG2 N-terminal transcript isoforms encoding L27 domains for their expression. Functionality of DLG2 isoforms and of LIN7A were evaluated in the 11q-deleted neuroblastoma cell line SKNAS. RESULTS In neuroblastoma only two DLG2 isoforms were expressed: isoform 2 and isoform 7/8. Using the array data we could determine that higher expression of DLG members that contain L27 domains correlated to better survival and prognosis. Whilst DLG1 showed a decrease in both isoforms with increased INSS stage, only the full length L27 containing DLG2 transcripts DLG2-isoform 7/8 showed a decrease in expression in high stage neuroblastoma. We could show that the protein encoded by DLG2-isoform 7 could bind to LIN7A, and increased DLG2-isoform 7 gene expression increased the expression of LIN7A, this reduced neuroblastoma cell proliferation and viability, with increased BAX/BCL2 ratio indicating increased apoptosis. CONCLUSION We have provided evidence that gene expression of the L27 domain containing DLG2-isoform 7/8 but not L27 domain lacking DLG2-isoform 2 is disrupted in neuroblastoma, in particular in the aggressive subsets of tumors. The presence of the complete L27 domain allows for the binding to LIN7A, which will control cell polarity and signaling, thus affecting cancer cell viability.
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Affiliation(s)
- Simon Keane
- Translational Medicine, School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Tommy Martinsson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Per Kogner
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Katarina Ejeskär
- Translational Medicine, School of Health Sciences, University of Skövde, Skövde, Sweden.
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3
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Kobler O, Weiglein A, Hartung K, Chen YC, Gerber B, Thomas U. A quick and versatile protocol for the 3D visualization of transgene expression across the whole body of larval Drosophila. J Neurogenet 2021; 35:306-319. [PMID: 33688796 DOI: 10.1080/01677063.2021.1892096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Larval Drosophila are used as a genetically accessible study case in many areas of biological research. Here we report a fast, robust and user-friendly procedure for the whole-body multi-fluorescence imaging of Drosophila larvae; the protocol has been optimized specifically for larvae by systematically tackling the pitfalls associated with clearing this small but cuticularized organism. Tests on various fluorescent proteins reveal that the recently introduced monomeric infrared fluorescent protein (mIFP) is particularly suitable for our approach. This approach comprises an effective, low-cost clearing protocol with minimal handling time and reduced toxicity in the reagents employed. It combines a success rate high enough to allow for small-scale screening approaches and a resolution sufficient for cellular-level analyses with light sheet and confocal microscopy. Given that publications and database documentations typically specify expression patterns of transgenic driver lines only within a given organ system of interest, the present procedure should be versatile enough to extend such documentation systematically to the whole body. As examples, the expression patterns of transgenic driver lines covering the majority of neurons, or subsets of chemosensory, central brain or motor neurons, are documented in the context of whole larval body volumes (using nsyb-Gal4, IR76b-Gal4, APL-Gal4 and mushroom body Kenyon cells, or OK371-Gal4, respectively). Notably, the presented protocol allows for triple-color fluorescence imaging with near-infrared, red and yellow fluorescent proteins.
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Affiliation(s)
- Oliver Kobler
- Leibniz Institute for Neurobiology, Combinatorial NeuroImaging Core Facility (CNI), Magdeburg, Germany
| | - Aliće Weiglein
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Kathrin Hartung
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Yi-Chun Chen
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Bertram Gerber
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Institute of Biology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke University, Magdeburg, Germany
| | - Ulrich Thomas
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
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Poovathumkadavil P, Jagla K. Genetic Control of Muscle Diversification and Homeostasis: Insights from Drosophila. Cells 2020; 9:cells9061543. [PMID: 32630420 PMCID: PMC7349286 DOI: 10.3390/cells9061543] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/13/2022] Open
Abstract
In the fruit fly, Drosophila melanogaster, the larval somatic muscles or the adult thoracic flight and leg muscles are the major voluntary locomotory organs. They share several developmental and structural similarities with vertebrate skeletal muscles. To ensure appropriate activity levels for their functions such as hatching in the embryo, crawling in the larva, and jumping and flying in adult flies all muscle components need to be maintained in a functionally stable or homeostatic state despite constant strain. This requires that the muscles develop in a coordinated manner with appropriate connections to other cell types they communicate with. Various signaling pathways as well as extrinsic and intrinsic factors are known to play a role during Drosophila muscle development, diversification, and homeostasis. In this review, we discuss genetic control mechanisms of muscle contraction, development, and homeostasis with particular emphasis on the contractile unit of the muscle, the sarcomere.
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Rademacher N, Schmerl B, Lardong JA, Wahl MC, Shoichet SA. MPP2 is a postsynaptic MAGUK scaffold protein that links SynCAM1 cell adhesion molecules to core components of the postsynaptic density. Sci Rep 2016; 6:35283. [PMID: 27756895 PMCID: PMC5069480 DOI: 10.1038/srep35283] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/15/2016] [Indexed: 02/07/2023] Open
Abstract
At neuronal synapses, multiprotein complexes of trans-synaptic adhesion molecules, scaffold proteins and neurotransmitter receptors assemble to essential building blocks required for synapse formation and maintenance. Here we describe a novel role for the membrane-associated guanylate kinase (MAGUK) protein MPP2 (MAGUK p55 subfamily member 2) at synapses of rat central neurons. Through interactions mediated by its C-terminal SH3-GK domain module, MPP2 binds to the abundant postsynaptic scaffold proteins PSD-95 and GKAP and localises to postsynaptic sites in hippocampal neurons. MPP2 also colocalises with the synaptic adhesion molecule SynCAM1. We demonstrate that the SynCAM1 C-terminus interacts directly with the MPP2 PDZ domain and that MPP2 does not interact in this manner with other highly abundant postsynaptic transmembrane proteins. Our results highlight a previously unexplored role for MPP2 at postsynaptic sites as a scaffold that links SynCAM1 cell adhesion molecules to core proteins of the postsynaptic density.
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Affiliation(s)
- Nils Rademacher
- Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Bettina Schmerl
- Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Jennifer A. Lardong
- Institute of Chemistry and Biochemistry, Structural Biochemistry, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany
| | - Markus C. Wahl
- Institute of Chemistry and Biochemistry, Structural Biochemistry, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany
| | - Sarah A. Shoichet
- Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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Presynaptic DLG regulates synaptic function through the localization of voltage-activated Ca(2+) Channels. Sci Rep 2016; 6:32132. [PMID: 27573697 PMCID: PMC5004195 DOI: 10.1038/srep32132] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 08/03/2016] [Indexed: 12/15/2022] Open
Abstract
The DLG-MAGUK subfamily of proteins plays a role on the recycling and clustering of glutamate receptors (GLUR) at the postsynaptic density. discs-large1 (dlg) is the only DLG-MAGUK gene in Drosophila and originates two main products, DLGA and DLGS97 which differ by the presence of an L27 domain. Combining electrophysiology, immunostaining and genetic manipulation at the pre and postsynaptic compartments we study the DLG contribution to the basal synaptic-function at the Drosophila larval neuromuscular junction. Our results reveal a specific function of DLGS97 in the regulation of the size of GLUR fields and their subunit composition. Strikingly the absence of any of DLG proteins at the presynaptic terminal disrupts the clustering and localization of the calcium channel DmCa1A subunit (Cacophony), decreases the action potential-evoked release probability and alters short-term plasticity. Our results show for the first time a crucial role of DLG proteins in the presynaptic function in vivo.
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Harden N, Wang SJH, Krieger C. Making the connection – shared molecular machinery and evolutionary links underlie the formation and plasticity of occluding junctions and synapses. J Cell Sci 2016; 129:3067-76. [DOI: 10.1242/jcs.186627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
The pleated septate junction (pSJ), an ancient structure for cell–cell contact in invertebrate epithelia, has protein components that are found in three more-recent junctional structures, the neuronal synapse, the paranodal region of the myelinated axon and the vertebrate epithelial tight junction. These more-recent structures appear to have evolved through alterations of the ancestral septate junction. During its formation in the developing animal, the pSJ exhibits plasticity, although the final structure is extremely robust. Similar to the immature pSJ, the synapse and tight junctions both exhibit plasticity, and we consider evidence that this plasticity comes at least in part from the interaction of members of the immunoglobulin cell adhesion molecule superfamily with highly regulated membrane-associated guanylate kinases. This plasticity regulation probably arose in order to modulate the ancestral pSJ and is maintained in the derived structures; we suggest that it would be beneficial when studying plasticity of one of these structures to consider the literature on the others. Finally, looking beyond the junctions, we highlight parallels between epithelial and synaptic membranes, which both show a polarized distribution of many of the same proteins – evidence that determinants of apicobasal polarity in epithelia also participate in patterning of the synapse.
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Affiliation(s)
- Nicholas Harden
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon Ji Hau Wang
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
| | - Charles Krieger
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
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Bera S, Raghuram V, Mikhaylova M, Kreutz MR. A plasmid-based expression system to study protein-protein interactions at the Golgi in vivo. Anal Biochem 2016; 502:50-52. [PMID: 26973219 DOI: 10.1016/j.ab.2016.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/20/2016] [Accepted: 02/24/2016] [Indexed: 01/23/2023]
Abstract
There is still an unmet need for simple methods to verify, visualize, and confirm protein-protein interactions in vivo. Here we describe a plasmid-based system to study such interactions. The system is based on the transmembrane domain (TMD) of the EF-hand Ca(2+) sensor protein calneuron-2. We show that fusion of 28 amino acids that include the TMD of calneuron-2 to proteins of interest results in prominent localization on the cytoplasmic side of the Golgi. The recruitment of binding partners to the protein of interest fused to this sequence can then be easily visualized by fluorescent tags.
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Affiliation(s)
- Sujoy Bera
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
| | - Vijeta Raghuram
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany; CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, 500007, India
| | - Marina Mikhaylova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany; Emmy Noether Group "Neuronal Protein Transport", Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany; Leibniz Group "Dendritic Organelles and Synaptic Function", Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
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9
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Harris KP, Littleton JT. Transmission, Development, and Plasticity of Synapses. Genetics 2015; 201:345-75. [PMID: 26447126 PMCID: PMC4596655 DOI: 10.1534/genetics.115.176529] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/28/2015] [Indexed: 01/03/2023] Open
Abstract
Chemical synapses are sites of contact and information transfer between a neuron and its partner cell. Each synapse is a specialized junction, where the presynaptic cell assembles machinery for the release of neurotransmitter, and the postsynaptic cell assembles components to receive and integrate this signal. Synapses also exhibit plasticity, during which synaptic function and/or structure are modified in response to activity. With a robust panel of genetic, imaging, and electrophysiology approaches, and strong evolutionary conservation of molecular components, Drosophila has emerged as an essential model system for investigating the mechanisms underlying synaptic assembly, function, and plasticity. We will discuss techniques for studying synapses in Drosophila, with a focus on the larval neuromuscular junction (NMJ), a well-established model glutamatergic synapse. Vesicle fusion, which underlies synaptic release of neurotransmitters, has been well characterized at this synapse. In addition, studies of synaptic assembly and organization of active zones and postsynaptic densities have revealed pathways that coordinate those events across the synaptic cleft. We will also review modes of synaptic growth and plasticity at the fly NMJ, and discuss how pre- and postsynaptic cells communicate to regulate plasticity in response to activity.
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Affiliation(s)
- Kathryn P Harris
- Department of Biology and Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - J Troy Littleton
- Department of Biology and Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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10
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Erdmann I, Marter K, Kobler O, Niehues S, Abele J, Müller A, Bussmann J, Storkebaum E, Ziv T, Thomas U, Dieterich DC. Cell-selective labelling of proteomes in Drosophila melanogaster. Nat Commun 2015; 6:7521. [PMID: 26138272 PMCID: PMC4507001 DOI: 10.1038/ncomms8521] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 05/16/2015] [Indexed: 01/06/2023] Open
Abstract
The specification and adaptability of cells rely on changes in protein composition. Nonetheless, uncovering proteome dynamics with cell-type-specific resolution remains challenging. Here we introduce a strategy for cell-specific analysis of newly synthesized proteomes by combining targeted expression of a mutated methionyl-tRNA synthetase (MetRS) with bioorthogonal or fluorescent non-canonical amino-acid-tagging techniques (BONCAT or FUNCAT). Substituting leucine by glycine within the MetRS-binding pocket (MetRSLtoG) enables incorporation of the non-canonical amino acid azidonorleucine (ANL) instead of methionine during translation. Newly synthesized proteins can thus be labelled by coupling the azide group of ANL to alkyne-bearing tags through ‘click chemistry'. To test these methods for applicability in vivo, we expressed MetRSLtoG cell specifically in Drosophila. FUNCAT and BONCAT reveal ANL incorporation into proteins selectively in cells expressing the mutated enzyme. Cell-type-specific FUNCAT and BONCAT, thus, constitute eligible techniques to study protein synthesis-dependent processes in complex and behaving organisms. Mutated tRNA synthetases can incorporate non-canonical amino acids into proteins. Erdmann et al. exploit this property to metabolically label newly synthesized proteins in selected cell types in Drosophila, and demonstrate their detection using proteomics (BONCAT) and fluorescence imaging (FUNCAT).
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Affiliation(s)
- Ines Erdmann
- 1] Research Group Neuronal Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg 39120, Germany [2] Research Group Neuralomics, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Kathrin Marter
- 1] Research Group Neuronal Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg 39120, Germany [2] Research Group Neuralomics, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Oliver Kobler
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Sven Niehues
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster 48149, Germany [2] Faculty of Medicine, University of Münster, Münster 48149, Germany
| | - Julia Abele
- 1] Research Group Neuronal Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg 39120, Germany [2] Research Group Neuralomics, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Anke Müller
- 1] Research Group Neuronal Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg 39120, Germany [2] Research Group Neuralomics, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Julia Bussmann
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster 48149, Germany [2] Faculty of Medicine, University of Münster, Münster 48149, Germany
| | - Erik Storkebaum
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster 48149, Germany [2] Faculty of Medicine, University of Münster, Münster 48149, Germany
| | - Tamar Ziv
- Smoler Proteomics Center, Faculty of Biology, Technion, Haifa 32000, Israel
| | - Ulrich Thomas
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Daniela C Dieterich
- 1] Research Group Neuronal Plasticity and Communication, Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg 39120, Germany [2] Research Group Neuralomics, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany [3] Center for Behavioral Brain Sciences, Magdeburg 39118, Germany
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Depner H, Lützkendorf J, Babkir HA, Sigrist SJ, Holt MG. Differential centrifugation-based biochemical fractionation of the Drosophila adult CNS. Nat Protoc 2014; 9:2796-808. [PMID: 25393777 DOI: 10.1038/nprot.2014.192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Drosophila is widely used as a genetic model in questions of development, cellular function and disease. Genetic screens in flies have proven to be incredibly powerful in identifying crucial components for synapse formation and function, particularly in the case of the presynaptic release machinery. Although modern biochemical methods can identify individual proteins and lipids (and their binding partners), they have typically been excluded from use in Drosophila for technical reasons. To bridge this essential gap between genetics and biochemistry, we developed a fractionation method to isolate various parts of the synaptic machinery from Drosophila, thus allowing it to be studied in unprecedented biochemical detail. This is only possible because our protocol has unique advantages in terms of enriching and preserving endogenous protein complexes. The procedure involves decapitation of adult flies, homogenization and differential centrifugation of fly heads, which allow subsequent purification of presynaptic (and to a limited degree postsynaptic) components. It is designed to require only a rudimentary knowledge of biochemical fractionation, and it takes ∼3.5 h. The yield is typically 4 mg of synaptic membrane protein per gram of Drosophila heads.
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Affiliation(s)
- Harald Depner
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Janine Lützkendorf
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Husam A Babkir
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Stephan J Sigrist
- 1] Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany. [2] NeuroCure Cluster of Excellence, Charité, Berlin, Germany
| | - Matthew G Holt
- Laboratory of Glia Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for the Biology of Disease, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
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12
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McDermott SM, Yang L, Halstead JM, Hamilton RS, Meignin C, Davis I. Drosophila Syncrip modulates the expression of mRNAs encoding key synaptic proteins required for morphology at the neuromuscular junction. RNA (NEW YORK, N.Y.) 2014; 20:1593-606. [PMID: 25171822 PMCID: PMC4174441 DOI: 10.1261/rna.045849.114] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 06/09/2014] [Indexed: 05/24/2023]
Abstract
Localized mRNA translation is thought to play a key role in synaptic plasticity, but the identity of the transcripts and the molecular mechanism underlying their function are still poorly understood. Here, we show that Syncrip, a regulator of localized translation in the Drosophila oocyte and a component of mammalian neuronal mRNA granules, is also expressed in the Drosophila larval neuromuscular junction, where it regulates synaptic growth. We use RNA-immunoprecipitation followed by high-throughput sequencing and qRT-PCR to show that Syncrip associates with a number of mRNAs encoding proteins with key synaptic functions, including msp-300, syd-1, neurexin-1, futsch, highwire, discs large, and α-spectrin. The protein levels of MSP-300, Discs large, and a number of others are significantly affected in syncrip null mutants. Furthermore, syncrip mutants show a reduction in MSP-300 protein levels and defects in muscle nuclear distribution characteristic of msp-300 mutants. Our results highlight a number of potential new players in localized translation during synaptic plasticity in the neuromuscular junction. We propose that Syncrip acts as a modulator of synaptic plasticity by regulating the translation of these key mRNAs encoding synaptic scaffolding proteins and other important components involved in synaptic growth and function.
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Affiliation(s)
- Suzanne M McDermott
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Lu Yang
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - James M Halstead
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Russell S Hamilton
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Carine Meignin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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13
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Blunk AD, Akbergenova Y, Cho RW, Lee J, Walldorf U, Xu K, Zhong G, Zhuang X, Littleton JT. Postsynaptic actin regulates active zone spacing and glutamate receptor apposition at the Drosophila neuromuscular junction. Mol Cell Neurosci 2014; 61:241-54. [PMID: 25066865 PMCID: PMC4134997 DOI: 10.1016/j.mcn.2014.07.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/14/2014] [Accepted: 07/23/2014] [Indexed: 12/26/2022] Open
Abstract
Synaptic communication requires precise alignment of presynaptic active zones with postsynaptic receptors to enable rapid and efficient neurotransmitter release. How transsynaptic signaling between connected partners organizes this synaptic apparatus is poorly understood. To further define the mechanisms that mediate synapse assembly, we carried out a chemical mutagenesis screen in Drosophila to identify mutants defective in the alignment of active zones with postsynaptic glutamate receptor fields at the larval neuromuscular junction. From this screen we identified a mutation in Actin 57B that disrupted synaptic morphology and presynaptic active zone organization. Actin 57B, one of six actin genes in Drosophila, is expressed within the postsynaptic bodywall musculature. The isolated allele, act(E84K), harbors a point mutation in a highly conserved glutamate residue in subdomain 1 that binds members of the Calponin Homology protein family, including spectrin. Homozygous act(E84K) mutants show impaired alignment and spacing of presynaptic active zones, as well as defects in apposition of active zones to postsynaptic glutamate receptor fields. act(E84K) mutants have disrupted postsynaptic actin networks surrounding presynaptic boutons, with the formation of aberrant actin swirls previously observed following disruption of postsynaptic spectrin. Consistent with a disruption of the postsynaptic actin cytoskeleton, spectrin, adducin and the PSD-95 homolog Discs-Large are all mislocalized in act(E84K) mutants. Genetic interactions between act(E84K) and neurexin mutants suggest that the postsynaptic actin cytoskeleton may function together with the Neurexin-Neuroligin transsynaptic signaling complex to mediate normal synapse development and presynaptic active zone organization.
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Affiliation(s)
- Aline D Blunk
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Richard W Cho
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Jihye Lee
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; The Department of Oral Pathology, School of Dentistry, Pusan National University, Republic of Korea
| | - Uwe Walldorf
- Department of Developmental Biology, University of Saarland, Homburg, Saar, Germany
| | - Ke Xu
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Guisheng Zhong
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States; Department of Physics, Harvard University, Cambridge, MA 02138, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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14
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Soukup SF, Pocha SM, Yuan M, Knust E. DLin-7 is required in postsynaptic lamina neurons to prevent light-induced photoreceptor degeneration in Drosophila. Curr Biol 2013; 23:1349-54. [PMID: 23850283 DOI: 10.1016/j.cub.2013.05.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 05/21/2013] [Accepted: 05/30/2013] [Indexed: 10/26/2022]
Abstract
Inherited retinal degeneration in humans is caused by mutations in a wide spectrum of genes that regulate photoreceptor development and homeostasis. Many of these genes are structurally and functionally conserved in Drosophila, making the fly eye an ideal system in which to study the cellular and molecular basis of blindness. DLin-7, the ortholog of vertebrate MALS/Veli, is a core component of the evolutionarily conserved Crumbs complex. Mutations in any core member of the Crb complex lead to retinal degeneration in Drosophila. Strikingly, mutations in the human ortholog, CRB1, result in retinitis pigmentosa 12 (RP12) and Leber congenital amaurosis, two severe retinal dystrophies. Unlike Crumbs, DLin-7 is expressed not only in photoreceptor cells but also in postsynaptic lamina neurons. Here, we show that DLin-7 is required in postsynaptic neurons, but not in photoreceptors such as Crumbs, to prevent light-dependent retinal degeneration. At the photoreceptor synapse, DLin-7 acts as part of a conserved DLin-7/CASK/DlgS97 complex required to control the number of capitate projections and active zones, important specializations in the photoreceptor synapse that are essential for proper neurotransmission. These results are the first to demonstrate that a postsynaptically acting protein prevents light-dependent photoreceptor degeneration and describe a novel, Crumbs-independent mechanism for photoreceptor degeneration.
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Affiliation(s)
- Sandra-Fausia Soukup
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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15
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Maiya R, Lee S, Berger KH, Kong EC, Slawson JB, Griffith LC, Takamiya K, Huganir RL, Margolis B, Heberlein U. DlgS97/SAP97, a neuronal isoform of discs large, regulates ethanol tolerance. PLoS One 2012; 7:e48967. [PMID: 23145041 PMCID: PMC3492131 DOI: 10.1371/journal.pone.0048967] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/01/2012] [Indexed: 11/19/2022] Open
Abstract
From a genetic screen for Drosophila melanogaster mutants with altered ethanol tolerance, we identified intolerant (intol), a novel allele of discs large 1 (dlg1). Dlg1 encodes Discs Large 1, a MAGUK (Membrane Associated Guanylate Kinase) family member that is the highly conserved homolog of mammalian PSD-95 and SAP97. The intol mutation disrupted specifically the expression of DlgS97, a SAP97 homolog, and one of two major protein isoforms encoded by dlg1 via alternative splicing. Expression of the major isoform, DlgA, a PSD-95 homolog, appeared unaffected. Ethanol tolerance in the intol mutant could be partially restored by transgenic expression of DlgS97, but not DlgA, in specific neurons of the fly's brain. Based on co-immunoprecipitation, DlgS97 forms a complex with N-methyl-D-aspartate (NMDA) receptors, a known target of ethanol. Consistent with these observations, flies expressing reduced levels of the essential NMDA receptor subunit dNR1 also showed reduced ethanol tolerance, as did mutants in the gene calcium/calmodulin-dependent protein kinase (caki), encoding the fly homolog of mammalian CASK, a known binding partner of DlgS97. Lastly, mice in which SAP97, the mammalian homolog of DlgS97, was conditionally deleted in adults failed to develop rapid tolerance to ethanol's sedative/hypnotic effects. We propose that DlgS97/SAP97 plays an important and conserved role in the development of tolerance to ethanol via NMDA receptor-mediated synaptic plasticity.
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Affiliation(s)
- Rajani Maiya
- Ernest Gallo Clinic and Research Center, Emeryville, California, United States of America
| | - Seonok Lee
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Karen H. Berger
- Ernest Gallo Clinic and Research Center, Emeryville, California, United States of America
| | - Eric C. Kong
- Ernest Gallo Clinic and Research Center, Emeryville, California, United States of America
| | - Justin B. Slawson
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Leslie C. Griffith
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Kogo Takamiya
- Department of Neuroscience, Faculty of Medicine, Graduate School of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
| | - Richard L. Huganir
- Department of Neuroscience and the Howard Hughes Medical Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Ben Margolis
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Ulrike Heberlein
- Ernest Gallo Clinic and Research Center, Emeryville, California, United States of America
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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16
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Oliva C, Escobedo P, Astorga C, Molina C, Sierralta J. Role of the MAGUK protein family in synapse formation and function. Dev Neurobiol 2012; 72:57-72. [PMID: 21739617 DOI: 10.1002/dneu.20949] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Synaptic function is crucially dependent on the spatial organization of the presynaptic and postsynaptic apparatuses and the juxtaposition of both membrane compartments. This precise arrangement is achieved by a protein network at the submembrane region of each cell that is built around scaffold proteins. The membrane-associated guanylate kinase (MAGUK) family of proteins is a widely expressed and well-conserved group of proteins that plays an essential role in the formation and regulation of this scaffolding. Here, we review general features of this protein family, focusing on the discs large and calcium/calmodulin-dependent serine protein kinase subfamilies of MAGUKs in the formation, function, and plasticity of synapses.
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Affiliation(s)
- Carlos Oliva
- Program of Physiology and Biophysics, Institute of Biomedical Sciences and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
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17
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Glutamate receptors in synaptic assembly and plasticity: case studies on fly NMJs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:3-28. [PMID: 22351049 DOI: 10.1007/978-3-7091-0932-8_1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The molecular and cellular mechanisms that control the composition and functionality of ionotropic glutamate receptors may be considered as most important "set screws" for adjusting excitatory transmission in the course of developmental and experience-dependent changes within neural networks. The Drosophila larval neuromuscular junction has emerged as one important invertebrate model system to study the formation, maintenance, and plasticity-related remodeling of glutamatergic synapses in vivo. By exploiting the unique genetic accessibility of this organism combined with diverse tools for manipulation and analysis including electrophysiology and state of the art imaging, considerable progress has been made to characterize the role of glutamate receptors during the orchestration of junctional development, synaptic activity, and synaptogenesis. Following an introduction to basic features of this model system, we will mainly focus on conceptually important findings such as the selective impact of glutamate receptor subtypes on the formation of new synapses, the coordination of presynaptic maturation and receptor subtype composition, the role of nonvesicularly released glutamate on the synaptic localization of receptors, or the homeostatic feedback of receptor functionality on presynaptic transmitter release.
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18
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Chen Y, Yang M, Deng J, Chen X, Ye Y, Zhu L, Liu J, Ye H, Shen Y, Li Y, Rao EJ, Fushimi K, Zhou X, Bigio EH, Mesulam M, Xu Q, Wu JY. Expression of human FUS protein in Drosophila leads to progressive neurodegeneration. Protein Cell 2011; 2:477-86. [PMID: 21748598 DOI: 10.1007/s13238-011-1065-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 06/23/2011] [Indexed: 12/12/2022] Open
Abstract
Mutations in the Fused in sarcoma/Translated in liposarcoma gene (FUS/TLS, FUS) have been identified among patients with amyotrophic lateral sclerosis (ALS). FUS protein aggregation is a major pathological hallmark of FUS proteinopathy, a group of neurodegenerative diseases characterized by FUS-immunoreactive inclusion bodies. We prepared transgenic Drosophila expressing either the wild type (Wt) or ALS-mutant human FUS protein (hFUS) using the UAS-Gal4 system. When expressing Wt, R524S or P525L mutant FUS in photoreceptors, mushroom bodies (MBs) or motor neurons (MNs), transgenic flies show age-dependent progressive neural damages, including axonal loss in MB neurons, morphological changes and functional impairment in MNs. The transgenic flies expressing the hFUS gene recapitulate key features of FUS proteinopathy, representing the first stable animal model for this group of devastating diseases.
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Affiliation(s)
- Yanbo Chen
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Science and Peking Union Medical College, Tsinghua University, Beijing, China
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19
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Bulgakova NA, Rentsch M, Knust E. Antagonistic functions of two stardust isoforms in Drosophila photoreceptor cells. Mol Biol Cell 2010; 21:3915-25. [PMID: 20861315 PMCID: PMC2982133 DOI: 10.1091/mbc.e09-10-0917] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Two Stardust isoforms are expressed in adult Drosophila photoreceptors, which associate with Crumbs and PATJ, but form distinct complexes. Sdt-H and Sdt-D have antagonistic functions on stalk membrane length and light-dependent retinal degeneration, suggesting a fine-tuned balance of different Crumbs complexes regulating photoreceptor homeostasis. Membrane-associated guanylate kinases (MAGUKs) are scaffolding proteins that organize supramolecular protein complexes, thereby partitioning the plasma membrane into spatially and functionally distinct subdomains. Their modular organization is ideally suited to organize protein complexes with cell type- or stage-specific composition, or both. Often more than one MAGUK isoform is expressed by one gene in the same cell, yet very little is known about their individual in vivo functions. Here, we show that two isoforms of Drosophila stardust, Sdt-H (formerly called Sdt-B2) and Sdt-D, which differ in their N terminus, are expressed in adult photoreceptors. Both isoforms associate with Crumbs and PATJ, constituents of the conserved Crumbs–Stardust complex. However, they form distinct complexes, localized at the stalk, a restricted region of the apical plasma membrane. Strikingly, Sdt-H and Sdt-D have antagonistic functions. While Sdt-H overexpression increases stalk membrane length and prevents light-dependent retinal degeneration, Sdt-D overexpression reduces stalk length and enhances light-dependent retinal degeneration. These results suggest that a fine-tuned balance of different Crumbs complexes regulates photoreceptor homeostasis.
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Affiliation(s)
- Natalia A Bulgakova
- Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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20
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Thomas U, Kobler O, Gundelfinger ED. TheDrosophilaLarval Neuromuscular Junction as a Model for Scaffold Complexes at Glutamatergic Synapses: Benefits and Limitations. J Neurogenet 2010; 24:109-19. [DOI: 10.3109/01677063.2010.493589] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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